From 266cf658efcf6ac33541a46740f74f50c79d2b6b Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:36 +0100 Subject: FS-Cache: Recruit a page flags for cache management Recruit a page flag to aid in cache management. The following extra flag is defined: (1) PG_fscache (PG_private_2) The marked page is backed by a local cache and is pinning resources in the cache driver. If PG_fscache is set, then things that checked for PG_private will now also check for that. This includes things like truncation and page invalidation. The function page_has_private() had been added to make the checks for both PG_private and PG_private_2 at the same time. Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Rik van Riel Acked-by: Al Viro Tested-by: Daire Byrne --- fs/splice.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'fs') diff --git a/fs/splice.c b/fs/splice.c index 4ed0ba44a96..dd727d43e5b 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -59,7 +59,8 @@ static int page_cache_pipe_buf_steal(struct pipe_inode_info *pipe, */ wait_on_page_writeback(page); - if (PagePrivate(page) && !try_to_release_page(page, GFP_KERNEL)) + if (page_has_private(page) && + !try_to_release_page(page, GFP_KERNEL)) goto out_unlock; /* -- cgit v1.2.3-70-g09d2 From 06b3db1b9bccdc8c2c743122a89745279e5ecc46 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:36 +0100 Subject: FS-Cache: Add main configuration option, module entry points and debugging Add the main configuration option, allowing FS-Cache to be selected; the module entry and exit functions and the debugging stuff used by these patches. The two configuration options added are: CONFIG_FSCACHE CONFIG_FSCACHE_DEBUG The first enables the facility, and the second makes the debugging statements enableable through the "debug" module parameter. The value of this parameter is a bitmask as described in: Documentation/filesystems/caching/fscache.txt The module can be loaded at this point, but all it will do at this point in the patch series is to start up the slow work facility and shut it down again. Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Al Viro Tested-by: Daire Byrne --- fs/Kconfig | 6 ++ fs/Makefile | 1 + fs/fscache/Kconfig | 22 +++++++ fs/fscache/Makefile | 8 +++ fs/fscache/internal.h | 165 ++++++++++++++++++++++++++++++++++++++++++++++++++ fs/fscache/main.c | 75 +++++++++++++++++++++++ 6 files changed, 277 insertions(+) create mode 100644 fs/fscache/Kconfig create mode 100644 fs/fscache/Makefile create mode 100644 fs/fscache/internal.h create mode 100644 fs/fscache/main.c (limited to 'fs') diff --git a/fs/Kconfig b/fs/Kconfig index cef8b18ceaa..3942df6ad04 100644 --- a/fs/Kconfig +++ b/fs/Kconfig @@ -66,6 +66,12 @@ config GENERIC_ACL bool select FS_POSIX_ACL +menu "Caches" + +source "fs/fscache/Kconfig" + +endmenu + if BLOCK menu "CD-ROM/DVD Filesystems" diff --git a/fs/Makefile b/fs/Makefile index b5cd8e18dd9..ff5a10d898c 100644 --- a/fs/Makefile +++ b/fs/Makefile @@ -63,6 +63,7 @@ obj-$(CONFIG_PROFILING) += dcookies.o obj-$(CONFIG_DLM) += dlm/ # Do not add any filesystems before this line +obj-$(CONFIG_FSCACHE) += fscache/ obj-$(CONFIG_REISERFS_FS) += reiserfs/ obj-$(CONFIG_EXT3_FS) += ext3/ # Before ext2 so root fs can be ext3 obj-$(CONFIG_EXT2_FS) += ext2/ diff --git a/fs/fscache/Kconfig b/fs/fscache/Kconfig new file mode 100644 index 00000000000..7c7bccd5eee --- /dev/null +++ b/fs/fscache/Kconfig @@ -0,0 +1,22 @@ + +config FSCACHE + tristate "General filesystem local caching manager" + depends on EXPERIMENTAL + select SLOW_WORK + help + This option enables a generic filesystem caching manager that can be + used by various network and other filesystems to cache data locally. + Different sorts of caches can be plugged in, depending on the + resources available. + + See Documentation/filesystems/caching/fscache.txt for more information. + +config FSCACHE_DEBUG + bool "Debug FS-Cache" + depends on FSCACHE + help + This permits debugging to be dynamically enabled in the local caching + management module. If this is set, the debugging output may be + enabled by setting bits in /sys/modules/fscache/parameter/debug. + + See Documentation/filesystems/caching/fscache.txt for more information. diff --git a/fs/fscache/Makefile b/fs/fscache/Makefile new file mode 100644 index 00000000000..f8038b83e0e --- /dev/null +++ b/fs/fscache/Makefile @@ -0,0 +1,8 @@ +# +# Makefile for general filesystem caching code +# + +fscache-y := \ + main.o + +obj-$(CONFIG_FSCACHE) := fscache.o diff --git a/fs/fscache/internal.h b/fs/fscache/internal.h new file mode 100644 index 00000000000..95dc92da715 --- /dev/null +++ b/fs/fscache/internal.h @@ -0,0 +1,165 @@ +/* Internal definitions for FS-Cache + * + * Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +/* + * Lock order, in the order in which multiple locks should be obtained: + * - fscache_addremove_sem + * - cookie->lock + * - cookie->parent->lock + * - cache->object_list_lock + * - object->lock + * - object->parent->lock + * - fscache_thread_lock + * + */ + +#include +#include + +#define FSCACHE_MIN_THREADS 4 +#define FSCACHE_MAX_THREADS 32 + +/* + * fsc-main.c + */ +extern unsigned fscache_defer_lookup; +extern unsigned fscache_defer_create; +extern unsigned fscache_debug; +extern struct kobject *fscache_root; + +/*****************************************************************************/ +/* + * debug tracing + */ +#define dbgprintk(FMT, ...) \ + printk(KERN_DEBUG "[%-6.6s] "FMT"\n", current->comm, ##__VA_ARGS__) + +/* make sure we maintain the format strings, even when debugging is disabled */ +static inline __attribute__((format(printf, 1, 2))) +void _dbprintk(const char *fmt, ...) +{ +} + +#define kenter(FMT, ...) dbgprintk("==> %s("FMT")", __func__, ##__VA_ARGS__) +#define kleave(FMT, ...) dbgprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__) +#define kdebug(FMT, ...) dbgprintk(FMT, ##__VA_ARGS__) + +#define kjournal(FMT, ...) _dbprintk(FMT, ##__VA_ARGS__) + +#ifdef __KDEBUG +#define _enter(FMT, ...) kenter(FMT, ##__VA_ARGS__) +#define _leave(FMT, ...) kleave(FMT, ##__VA_ARGS__) +#define _debug(FMT, ...) kdebug(FMT, ##__VA_ARGS__) + +#elif defined(CONFIG_FSCACHE_DEBUG) +#define _enter(FMT, ...) \ +do { \ + if (__do_kdebug(ENTER)) \ + kenter(FMT, ##__VA_ARGS__); \ +} while (0) + +#define _leave(FMT, ...) \ +do { \ + if (__do_kdebug(LEAVE)) \ + kleave(FMT, ##__VA_ARGS__); \ +} while (0) + +#define _debug(FMT, ...) \ +do { \ + if (__do_kdebug(DEBUG)) \ + kdebug(FMT, ##__VA_ARGS__); \ +} while (0) + +#else +#define _enter(FMT, ...) _dbprintk("==> %s("FMT")", __func__, ##__VA_ARGS__) +#define _leave(FMT, ...) _dbprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__) +#define _debug(FMT, ...) _dbprintk(FMT, ##__VA_ARGS__) +#endif + +/* + * determine whether a particular optional debugging point should be logged + * - we need to go through three steps to persuade cpp to correctly join the + * shorthand in FSCACHE_DEBUG_LEVEL with its prefix + */ +#define ____do_kdebug(LEVEL, POINT) \ + unlikely((fscache_debug & \ + (FSCACHE_POINT_##POINT << (FSCACHE_DEBUG_ ## LEVEL * 3)))) +#define ___do_kdebug(LEVEL, POINT) \ + ____do_kdebug(LEVEL, POINT) +#define __do_kdebug(POINT) \ + ___do_kdebug(FSCACHE_DEBUG_LEVEL, POINT) + +#define FSCACHE_DEBUG_CACHE 0 +#define FSCACHE_DEBUG_COOKIE 1 +#define FSCACHE_DEBUG_PAGE 2 +#define FSCACHE_DEBUG_OPERATION 3 + +#define FSCACHE_POINT_ENTER 1 +#define FSCACHE_POINT_LEAVE 2 +#define FSCACHE_POINT_DEBUG 4 + +#ifndef FSCACHE_DEBUG_LEVEL +#define FSCACHE_DEBUG_LEVEL CACHE +#endif + +/* + * assertions + */ +#if 1 /* defined(__KDEBUGALL) */ + +#define ASSERT(X) \ +do { \ + if (unlikely(!(X))) { \ + printk(KERN_ERR "\n"); \ + printk(KERN_ERR "FS-Cache: Assertion failed\n"); \ + BUG(); \ + } \ +} while (0) + +#define ASSERTCMP(X, OP, Y) \ +do { \ + if (unlikely(!((X) OP (Y)))) { \ + printk(KERN_ERR "\n"); \ + printk(KERN_ERR "FS-Cache: Assertion failed\n"); \ + printk(KERN_ERR "%lx " #OP " %lx is false\n", \ + (unsigned long)(X), (unsigned long)(Y)); \ + BUG(); \ + } \ +} while (0) + +#define ASSERTIF(C, X) \ +do { \ + if (unlikely((C) && !(X))) { \ + printk(KERN_ERR "\n"); \ + printk(KERN_ERR "FS-Cache: Assertion failed\n"); \ + BUG(); \ + } \ +} while (0) + +#define ASSERTIFCMP(C, X, OP, Y) \ +do { \ + if (unlikely((C) && !((X) OP (Y)))) { \ + printk(KERN_ERR "\n"); \ + printk(KERN_ERR "FS-Cache: Assertion failed\n"); \ + printk(KERN_ERR "%lx " #OP " %lx is false\n", \ + (unsigned long)(X), (unsigned long)(Y)); \ + BUG(); \ + } \ +} while (0) + +#else + +#define ASSERT(X) do {} while (0) +#define ASSERTCMP(X, OP, Y) do {} while (0) +#define ASSERTIF(C, X) do {} while (0) +#define ASSERTIFCMP(C, X, OP, Y) do {} while (0) + +#endif /* assert or not */ diff --git a/fs/fscache/main.c b/fs/fscache/main.c new file mode 100644 index 00000000000..76f7c69079c --- /dev/null +++ b/fs/fscache/main.c @@ -0,0 +1,75 @@ +/* General filesystem local caching manager + * + * Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#define FSCACHE_DEBUG_LEVEL CACHE +#include +#include +#include +#include +#include +#include "internal.h" + +MODULE_DESCRIPTION("FS Cache Manager"); +MODULE_AUTHOR("Red Hat, Inc."); +MODULE_LICENSE("GPL"); + +unsigned fscache_defer_lookup = 1; +module_param_named(defer_lookup, fscache_defer_lookup, uint, + S_IWUSR | S_IRUGO); +MODULE_PARM_DESC(fscache_defer_lookup, + "Defer cookie lookup to background thread"); + +unsigned fscache_defer_create = 1; +module_param_named(defer_create, fscache_defer_create, uint, + S_IWUSR | S_IRUGO); +MODULE_PARM_DESC(fscache_defer_create, + "Defer cookie creation to background thread"); + +unsigned fscache_debug; +module_param_named(debug, fscache_debug, uint, + S_IWUSR | S_IRUGO); +MODULE_PARM_DESC(fscache_debug, + "FS-Cache debugging mask"); + +struct kobject *fscache_root; + +/* + * initialise the fs caching module + */ +static int __init fscache_init(void) +{ + int ret; + + ret = slow_work_register_user(); + if (ret < 0) + goto error_slow_work; + + printk(KERN_NOTICE "FS-Cache: Loaded\n"); + return 0; + +error_slow_work: + return ret; +} + +fs_initcall(fscache_init); + +/* + * clean up on module removal + */ +static void __exit fscache_exit(void) +{ + _enter(""); + + slow_work_unregister_user(); + printk(KERN_NOTICE "FS-Cache: Unloaded\n"); +} + +module_exit(fscache_exit); -- cgit v1.2.3-70-g09d2 From 7394daa8c61dfda4baa687f133748fa0b599b017 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:37 +0100 Subject: FS-Cache: Add use of /proc and presentation of statistics Make FS-Cache create its /proc interface and present various statistical information through it. Also provide the functions for updating this information. These features are enabled by: CONFIG_FSCACHE_PROC CONFIG_FSCACHE_STATS CONFIG_FSCACHE_HISTOGRAM The /proc directory for FS-Cache is also exported so that caching modules can add their own statistics there too. The FS-Cache module is loadable at this point, and the statistics files can be examined by userspace: cat /proc/fs/fscache/stats cat /proc/fs/fscache/histogram Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Al Viro Tested-by: Daire Byrne --- Documentation/filesystems/caching/backend-api.txt | 6 - Documentation/filesystems/caching/fscache.txt | 12 +- fs/fscache/Kconfig | 34 ++++ fs/fscache/Makefile | 4 + fs/fscache/histogram.c | 109 +++++++++++ fs/fscache/internal.h | 127 +++++++++++++ fs/fscache/main.c | 7 + fs/fscache/proc.c | 68 +++++++ fs/fscache/stats.c | 212 ++++++++++++++++++++++ include/linux/fscache-cache.h | 4 - 10 files changed, 566 insertions(+), 17 deletions(-) create mode 100644 fs/fscache/histogram.c create mode 100644 fs/fscache/proc.c create mode 100644 fs/fscache/stats.c (limited to 'fs') diff --git a/Documentation/filesystems/caching/backend-api.txt b/Documentation/filesystems/caching/backend-api.txt index 17723053aa9..382d52cdaf2 100644 --- a/Documentation/filesystems/caching/backend-api.txt +++ b/Documentation/filesystems/caching/backend-api.txt @@ -100,12 +100,6 @@ A sysfs directory called /sys/fs/fscache// is created if CONFIG_SYSFS is enabled. This is accessible through the kobject struct fscache_cache::kobj and is for use by the cache as it sees fit. -The cache driver may create itself a directory named for the cache type in the -/proc/fs/fscache/ directory. This is available if CONFIG_FSCACHE_PROC is -enabled and is accessible through: - - struct proc_dir_entry *proc_fscache; - ======================== RELEVANT DATA STRUCTURES diff --git a/Documentation/filesystems/caching/fscache.txt b/Documentation/filesystems/caching/fscache.txt index a759d916273..0a751f3c2c7 100644 --- a/Documentation/filesystems/caching/fscache.txt +++ b/Documentation/filesystems/caching/fscache.txt @@ -195,7 +195,6 @@ STATISTICAL INFORMATION If FS-Cache is compiled with the following options enabled: - CONFIG_FSCACHE_PROC=y (implied by the following two) CONFIG_FSCACHE_STATS=y CONFIG_FSCACHE_HISTOGRAM=y @@ -275,7 +274,7 @@ proc files. (*) /proc/fs/fscache/histogram cat /proc/fs/fscache/histogram - +HZ +TIME OBJ INST OP RUNS OBJ RUNS RETRV DLY RETRIEVLS + JIFS SECS OBJ INST OP RUNS OBJ RUNS RETRV DLY RETRIEVLS ===== ===== ========= ========= ========= ========= ========= This shows the breakdown of the number of times each amount of time @@ -291,16 +290,16 @@ proc files. RETRIEVLS Time between beginning and end of a retrieval Each row shows the number of events that took a particular range of times. - Each step is 1 jiffy in size. The +HZ column indicates the particular - jiffy range covered, and the +TIME field the equivalent number of seconds. + Each step is 1 jiffy in size. The JIFS column indicates the particular + jiffy range covered, and the SECS field the equivalent number of seconds. ========= DEBUGGING ========= -The FS-Cache facility can have runtime debugging enabled by adjusting the value -in: +If CONFIG_FSCACHE_DEBUG is enabled, the FS-Cache facility can have runtime +debugging enabled by adjusting the value in: /sys/module/fscache/parameters/debug @@ -327,4 +326,3 @@ the control file. For example: echo $((1|8|64)) >/sys/module/fscache/parameters/debug will turn on all function entry debugging. - diff --git a/fs/fscache/Kconfig b/fs/fscache/Kconfig index 7c7bccd5eee..9bbb8ce7bea 100644 --- a/fs/fscache/Kconfig +++ b/fs/fscache/Kconfig @@ -11,6 +11,40 @@ config FSCACHE See Documentation/filesystems/caching/fscache.txt for more information. +config FSCACHE_STATS + bool "Gather statistical information on local caching" + depends on FSCACHE && PROC_FS + help + This option causes statistical information to be gathered on local + caching and exported through file: + + /proc/fs/fscache/stats + + The gathering of statistics adds a certain amount of overhead to + execution as there are a quite a few stats gathered, and on a + multi-CPU system these may be on cachelines that keep bouncing + between CPUs. On the other hand, the stats are very useful for + debugging purposes. Saying 'Y' here is recommended. + + See Documentation/filesystems/caching/fscache.txt for more information. + +config FSCACHE_HISTOGRAM + bool "Gather latency information on local caching" + depends on FSCACHE && PROC_FS + help + This option causes latency information to be gathered on local + caching and exported through file: + + /proc/fs/fscache/histogram + + The generation of this histogram adds a certain amount of overhead to + execution as there are a number of points at which data is gathered, + and on a multi-CPU system these may be on cachelines that keep + bouncing between CPUs. On the other hand, the histogram may be + useful for debugging purposes. Saying 'N' here is recommended. + + See Documentation/filesystems/caching/fscache.txt for more information. + config FSCACHE_DEBUG bool "Debug FS-Cache" depends on FSCACHE diff --git a/fs/fscache/Makefile b/fs/fscache/Makefile index f8038b83e0e..1384823a160 100644 --- a/fs/fscache/Makefile +++ b/fs/fscache/Makefile @@ -5,4 +5,8 @@ fscache-y := \ main.o +fscache-$(CONFIG_PROC_FS) += proc.o +fscache-$(CONFIG_FSCACHE_STATS) += stats.o +fscache-$(CONFIG_FSCACHE_HISTOGRAM) += histogram.o + obj-$(CONFIG_FSCACHE) := fscache.o diff --git a/fs/fscache/histogram.c b/fs/fscache/histogram.c new file mode 100644 index 00000000000..bad496748a5 --- /dev/null +++ b/fs/fscache/histogram.c @@ -0,0 +1,109 @@ +/* FS-Cache latency histogram + * + * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#define FSCACHE_DEBUG_LEVEL THREAD +#include +#include +#include +#include "internal.h" + +atomic_t fscache_obj_instantiate_histogram[HZ]; +atomic_t fscache_objs_histogram[HZ]; +atomic_t fscache_ops_histogram[HZ]; +atomic_t fscache_retrieval_delay_histogram[HZ]; +atomic_t fscache_retrieval_histogram[HZ]; + +/* + * display the time-taken histogram + */ +static int fscache_histogram_show(struct seq_file *m, void *v) +{ + unsigned long index; + unsigned n[5], t; + + switch ((unsigned long) v) { + case 1: + seq_puts(m, "JIFS SECS OBJ INST OP RUNS OBJ RUNS " + " RETRV DLY RETRIEVLS\n"); + return 0; + case 2: + seq_puts(m, "===== ===== ========= ========= =========" + " ========= =========\n"); + return 0; + default: + index = (unsigned long) v - 3; + n[0] = atomic_read(&fscache_obj_instantiate_histogram[index]); + n[1] = atomic_read(&fscache_ops_histogram[index]); + n[2] = atomic_read(&fscache_objs_histogram[index]); + n[3] = atomic_read(&fscache_retrieval_delay_histogram[index]); + n[4] = atomic_read(&fscache_retrieval_histogram[index]); + if (!(n[0] | n[1] | n[2] | n[3] | n[4])) + return 0; + + t = (index * 1000) / HZ; + + seq_printf(m, "%4lu 0.%03u %9u %9u %9u %9u %9u\n", + index, t, n[0], n[1], n[2], n[3], n[4]); + return 0; + } +} + +/* + * set up the iterator to start reading from the first line + */ +static void *fscache_histogram_start(struct seq_file *m, loff_t *_pos) +{ + if ((unsigned long long)*_pos >= HZ + 2) + return NULL; + if (*_pos == 0) + *_pos = 1; + return (void *)(unsigned long) *_pos; +} + +/* + * move to the next line + */ +static void *fscache_histogram_next(struct seq_file *m, void *v, loff_t *pos) +{ + (*pos)++; + return (unsigned long long)*pos > HZ + 2 ? + NULL : (void *)(unsigned long) *pos; +} + +/* + * clean up after reading + */ +static void fscache_histogram_stop(struct seq_file *m, void *v) +{ +} + +static const struct seq_operations fscache_histogram_ops = { + .start = fscache_histogram_start, + .stop = fscache_histogram_stop, + .next = fscache_histogram_next, + .show = fscache_histogram_show, +}; + +/* + * open "/proc/fs/fscache/histogram" to provide latency data + */ +static int fscache_histogram_open(struct inode *inode, struct file *file) +{ + return seq_open(file, &fscache_histogram_ops); +} + +const struct file_operations fscache_histogram_fops = { + .owner = THIS_MODULE, + .open = fscache_histogram_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, +}; diff --git a/fs/fscache/internal.h b/fs/fscache/internal.h index 95dc92da715..16f9f1f46e4 100644 --- a/fs/fscache/internal.h +++ b/fs/fscache/internal.h @@ -27,6 +27,30 @@ #define FSCACHE_MIN_THREADS 4 #define FSCACHE_MAX_THREADS 32 +/* + * fsc-histogram.c + */ +#ifdef CONFIG_FSCACHE_HISTOGRAM +extern atomic_t fscache_obj_instantiate_histogram[HZ]; +extern atomic_t fscache_objs_histogram[HZ]; +extern atomic_t fscache_ops_histogram[HZ]; +extern atomic_t fscache_retrieval_delay_histogram[HZ]; +extern atomic_t fscache_retrieval_histogram[HZ]; + +static inline void fscache_hist(atomic_t histogram[], unsigned long start_jif) +{ + unsigned long jif = jiffies - start_jif; + if (jif >= HZ) + jif = HZ - 1; + atomic_inc(&histogram[jif]); +} + +extern const struct file_operations fscache_histogram_fops; + +#else +#define fscache_hist(hist, start_jif) do {} while (0) +#endif + /* * fsc-main.c */ @@ -35,6 +59,109 @@ extern unsigned fscache_defer_create; extern unsigned fscache_debug; extern struct kobject *fscache_root; +/* + * fsc-proc.c + */ +#ifdef CONFIG_PROC_FS +extern int __init fscache_proc_init(void); +extern void fscache_proc_cleanup(void); +#else +#define fscache_proc_init() (0) +#define fscache_proc_cleanup() do {} while (0) +#endif + +/* + * fsc-stats.c + */ +#ifdef CONFIG_FSCACHE_STATS +extern atomic_t fscache_n_ops_processed[FSCACHE_MAX_THREADS]; +extern atomic_t fscache_n_objs_processed[FSCACHE_MAX_THREADS]; + +extern atomic_t fscache_n_op_pend; +extern atomic_t fscache_n_op_run; +extern atomic_t fscache_n_op_enqueue; +extern atomic_t fscache_n_op_deferred_release; +extern atomic_t fscache_n_op_release; +extern atomic_t fscache_n_op_gc; + +extern atomic_t fscache_n_attr_changed; +extern atomic_t fscache_n_attr_changed_ok; +extern atomic_t fscache_n_attr_changed_nobufs; +extern atomic_t fscache_n_attr_changed_nomem; +extern atomic_t fscache_n_attr_changed_calls; + +extern atomic_t fscache_n_allocs; +extern atomic_t fscache_n_allocs_ok; +extern atomic_t fscache_n_allocs_wait; +extern atomic_t fscache_n_allocs_nobufs; +extern atomic_t fscache_n_alloc_ops; +extern atomic_t fscache_n_alloc_op_waits; + +extern atomic_t fscache_n_retrievals; +extern atomic_t fscache_n_retrievals_ok; +extern atomic_t fscache_n_retrievals_wait; +extern atomic_t fscache_n_retrievals_nodata; +extern atomic_t fscache_n_retrievals_nobufs; +extern atomic_t fscache_n_retrievals_intr; +extern atomic_t fscache_n_retrievals_nomem; +extern atomic_t fscache_n_retrieval_ops; +extern atomic_t fscache_n_retrieval_op_waits; + +extern atomic_t fscache_n_stores; +extern atomic_t fscache_n_stores_ok; +extern atomic_t fscache_n_stores_again; +extern atomic_t fscache_n_stores_nobufs; +extern atomic_t fscache_n_stores_oom; +extern atomic_t fscache_n_store_ops; +extern atomic_t fscache_n_store_calls; + +extern atomic_t fscache_n_marks; +extern atomic_t fscache_n_uncaches; + +extern atomic_t fscache_n_acquires; +extern atomic_t fscache_n_acquires_null; +extern atomic_t fscache_n_acquires_no_cache; +extern atomic_t fscache_n_acquires_ok; +extern atomic_t fscache_n_acquires_nobufs; +extern atomic_t fscache_n_acquires_oom; + +extern atomic_t fscache_n_updates; +extern atomic_t fscache_n_updates_null; +extern atomic_t fscache_n_updates_run; + +extern atomic_t fscache_n_relinquishes; +extern atomic_t fscache_n_relinquishes_null; +extern atomic_t fscache_n_relinquishes_waitcrt; + +extern atomic_t fscache_n_cookie_index; +extern atomic_t fscache_n_cookie_data; +extern atomic_t fscache_n_cookie_special; + +extern atomic_t fscache_n_object_alloc; +extern atomic_t fscache_n_object_no_alloc; +extern atomic_t fscache_n_object_lookups; +extern atomic_t fscache_n_object_lookups_negative; +extern atomic_t fscache_n_object_lookups_positive; +extern atomic_t fscache_n_object_created; +extern atomic_t fscache_n_object_avail; +extern atomic_t fscache_n_object_dead; + +extern atomic_t fscache_n_checkaux_none; +extern atomic_t fscache_n_checkaux_okay; +extern atomic_t fscache_n_checkaux_update; +extern atomic_t fscache_n_checkaux_obsolete; + +static inline void fscache_stat(atomic_t *stat) +{ + atomic_inc(stat); +} + +extern const struct file_operations fscache_stats_fops; +#else + +#define fscache_stat(stat) do {} while (0) +#endif + /*****************************************************************************/ /* * debug tracing diff --git a/fs/fscache/main.c b/fs/fscache/main.c index 76f7c69079c..7c734b7fb18 100644 --- a/fs/fscache/main.c +++ b/fs/fscache/main.c @@ -52,9 +52,15 @@ static int __init fscache_init(void) if (ret < 0) goto error_slow_work; + ret = fscache_proc_init(); + if (ret < 0) + goto error_proc; + printk(KERN_NOTICE "FS-Cache: Loaded\n"); return 0; +error_proc: + slow_work_unregister_user(); error_slow_work: return ret; } @@ -68,6 +74,7 @@ static void __exit fscache_exit(void) { _enter(""); + fscache_proc_cleanup(); slow_work_unregister_user(); printk(KERN_NOTICE "FS-Cache: Unloaded\n"); } diff --git a/fs/fscache/proc.c b/fs/fscache/proc.c new file mode 100644 index 00000000000..beeab44bc31 --- /dev/null +++ b/fs/fscache/proc.c @@ -0,0 +1,68 @@ +/* FS-Cache statistics viewing interface + * + * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#define FSCACHE_DEBUG_LEVEL OPERATION +#include +#include +#include +#include "internal.h" + +/* + * initialise the /proc/fs/fscache/ directory + */ +int __init fscache_proc_init(void) +{ + _enter(""); + + if (!proc_mkdir("fs/fscache", NULL)) + goto error_dir; + +#ifdef CONFIG_FSCACHE_STATS + if (!proc_create("fs/fscache/stats", S_IFREG | 0444, NULL, + &fscache_stats_fops)) + goto error_stats; +#endif + +#ifdef CONFIG_FSCACHE_HISTOGRAM + if (!proc_create("fs/fscache/histogram", S_IFREG | 0444, NULL, + &fscache_histogram_fops)) + goto error_histogram; +#endif + + _leave(" = 0"); + return 0; + +#ifdef CONFIG_FSCACHE_HISTOGRAM +error_histogram: +#endif +#ifdef CONFIG_FSCACHE_STATS + remove_proc_entry("fs/fscache/stats", NULL); +error_stats: +#endif + remove_proc_entry("fs/fscache", NULL); +error_dir: + _leave(" = -ENOMEM"); + return -ENOMEM; +} + +/* + * clean up the /proc/fs/fscache/ directory + */ +void fscache_proc_cleanup(void) +{ +#ifdef CONFIG_FSCACHE_HISTOGRAM + remove_proc_entry("fs/fscache/histogram", NULL); +#endif +#ifdef CONFIG_FSCACHE_STATS + remove_proc_entry("fs/fscache/stats", NULL); +#endif + remove_proc_entry("fs/fscache", NULL); +} diff --git a/fs/fscache/stats.c b/fs/fscache/stats.c new file mode 100644 index 00000000000..65deb99e756 --- /dev/null +++ b/fs/fscache/stats.c @@ -0,0 +1,212 @@ +/* FS-Cache statistics + * + * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#define FSCACHE_DEBUG_LEVEL THREAD +#include +#include +#include +#include "internal.h" + +/* + * operation counters + */ +atomic_t fscache_n_op_pend; +atomic_t fscache_n_op_run; +atomic_t fscache_n_op_enqueue; +atomic_t fscache_n_op_requeue; +atomic_t fscache_n_op_deferred_release; +atomic_t fscache_n_op_release; +atomic_t fscache_n_op_gc; + +atomic_t fscache_n_attr_changed; +atomic_t fscache_n_attr_changed_ok; +atomic_t fscache_n_attr_changed_nobufs; +atomic_t fscache_n_attr_changed_nomem; +atomic_t fscache_n_attr_changed_calls; + +atomic_t fscache_n_allocs; +atomic_t fscache_n_allocs_ok; +atomic_t fscache_n_allocs_wait; +atomic_t fscache_n_allocs_nobufs; +atomic_t fscache_n_alloc_ops; +atomic_t fscache_n_alloc_op_waits; + +atomic_t fscache_n_retrievals; +atomic_t fscache_n_retrievals_ok; +atomic_t fscache_n_retrievals_wait; +atomic_t fscache_n_retrievals_nodata; +atomic_t fscache_n_retrievals_nobufs; +atomic_t fscache_n_retrievals_intr; +atomic_t fscache_n_retrievals_nomem; +atomic_t fscache_n_retrieval_ops; +atomic_t fscache_n_retrieval_op_waits; + +atomic_t fscache_n_stores; +atomic_t fscache_n_stores_ok; +atomic_t fscache_n_stores_again; +atomic_t fscache_n_stores_nobufs; +atomic_t fscache_n_stores_oom; +atomic_t fscache_n_store_ops; +atomic_t fscache_n_store_calls; + +atomic_t fscache_n_marks; +atomic_t fscache_n_uncaches; + +atomic_t fscache_n_acquires; +atomic_t fscache_n_acquires_null; +atomic_t fscache_n_acquires_no_cache; +atomic_t fscache_n_acquires_ok; +atomic_t fscache_n_acquires_nobufs; +atomic_t fscache_n_acquires_oom; + +atomic_t fscache_n_updates; +atomic_t fscache_n_updates_null; +atomic_t fscache_n_updates_run; + +atomic_t fscache_n_relinquishes; +atomic_t fscache_n_relinquishes_null; +atomic_t fscache_n_relinquishes_waitcrt; + +atomic_t fscache_n_cookie_index; +atomic_t fscache_n_cookie_data; +atomic_t fscache_n_cookie_special; + +atomic_t fscache_n_object_alloc; +atomic_t fscache_n_object_no_alloc; +atomic_t fscache_n_object_lookups; +atomic_t fscache_n_object_lookups_negative; +atomic_t fscache_n_object_lookups_positive; +atomic_t fscache_n_object_created; +atomic_t fscache_n_object_avail; +atomic_t fscache_n_object_dead; + +atomic_t fscache_n_checkaux_none; +atomic_t fscache_n_checkaux_okay; +atomic_t fscache_n_checkaux_update; +atomic_t fscache_n_checkaux_obsolete; + +/* + * display the general statistics + */ +static int fscache_stats_show(struct seq_file *m, void *v) +{ + seq_puts(m, "FS-Cache statistics\n"); + + seq_printf(m, "Cookies: idx=%u dat=%u spc=%u\n", + atomic_read(&fscache_n_cookie_index), + atomic_read(&fscache_n_cookie_data), + atomic_read(&fscache_n_cookie_special)); + + seq_printf(m, "Objects: alc=%u nal=%u avl=%u ded=%u\n", + atomic_read(&fscache_n_object_alloc), + atomic_read(&fscache_n_object_no_alloc), + atomic_read(&fscache_n_object_avail), + atomic_read(&fscache_n_object_dead)); + seq_printf(m, "ChkAux : non=%u ok=%u upd=%u obs=%u\n", + atomic_read(&fscache_n_checkaux_none), + atomic_read(&fscache_n_checkaux_okay), + atomic_read(&fscache_n_checkaux_update), + atomic_read(&fscache_n_checkaux_obsolete)); + + seq_printf(m, "Pages : mrk=%u unc=%u\n", + atomic_read(&fscache_n_marks), + atomic_read(&fscache_n_uncaches)); + + seq_printf(m, "Acquire: n=%u nul=%u noc=%u ok=%u nbf=%u" + " oom=%u\n", + atomic_read(&fscache_n_acquires), + atomic_read(&fscache_n_acquires_null), + atomic_read(&fscache_n_acquires_no_cache), + atomic_read(&fscache_n_acquires_ok), + atomic_read(&fscache_n_acquires_nobufs), + atomic_read(&fscache_n_acquires_oom)); + + seq_printf(m, "Lookups: n=%u neg=%u pos=%u crt=%u\n", + atomic_read(&fscache_n_object_lookups), + atomic_read(&fscache_n_object_lookups_negative), + atomic_read(&fscache_n_object_lookups_positive), + atomic_read(&fscache_n_object_created)); + + seq_printf(m, "Updates: n=%u nul=%u run=%u\n", + atomic_read(&fscache_n_updates), + atomic_read(&fscache_n_updates_null), + atomic_read(&fscache_n_updates_run)); + + seq_printf(m, "Relinqs: n=%u nul=%u wcr=%u\n", + atomic_read(&fscache_n_relinquishes), + atomic_read(&fscache_n_relinquishes_null), + atomic_read(&fscache_n_relinquishes_waitcrt)); + + seq_printf(m, "AttrChg: n=%u ok=%u nbf=%u oom=%u run=%u\n", + atomic_read(&fscache_n_attr_changed), + atomic_read(&fscache_n_attr_changed_ok), + atomic_read(&fscache_n_attr_changed_nobufs), + atomic_read(&fscache_n_attr_changed_nomem), + atomic_read(&fscache_n_attr_changed_calls)); + + seq_printf(m, "Allocs : n=%u ok=%u wt=%u nbf=%u\n", + atomic_read(&fscache_n_allocs), + atomic_read(&fscache_n_allocs_ok), + atomic_read(&fscache_n_allocs_wait), + atomic_read(&fscache_n_allocs_nobufs)); + seq_printf(m, "Allocs : ops=%u owt=%u\n", + atomic_read(&fscache_n_alloc_ops), + atomic_read(&fscache_n_alloc_op_waits)); + + seq_printf(m, "Retrvls: n=%u ok=%u wt=%u nod=%u nbf=%u" + " int=%u oom=%u\n", + atomic_read(&fscache_n_retrievals), + atomic_read(&fscache_n_retrievals_ok), + atomic_read(&fscache_n_retrievals_wait), + atomic_read(&fscache_n_retrievals_nodata), + atomic_read(&fscache_n_retrievals_nobufs), + atomic_read(&fscache_n_retrievals_intr), + atomic_read(&fscache_n_retrievals_nomem)); + seq_printf(m, "Retrvls: ops=%u owt=%u\n", + atomic_read(&fscache_n_retrieval_ops), + atomic_read(&fscache_n_retrieval_op_waits)); + + seq_printf(m, "Stores : n=%u ok=%u agn=%u nbf=%u oom=%u\n", + atomic_read(&fscache_n_stores), + atomic_read(&fscache_n_stores_ok), + atomic_read(&fscache_n_stores_again), + atomic_read(&fscache_n_stores_nobufs), + atomic_read(&fscache_n_stores_oom)); + seq_printf(m, "Stores : ops=%u run=%u\n", + atomic_read(&fscache_n_store_ops), + atomic_read(&fscache_n_store_calls)); + + seq_printf(m, "Ops : pend=%u run=%u enq=%u\n", + atomic_read(&fscache_n_op_pend), + atomic_read(&fscache_n_op_run), + atomic_read(&fscache_n_op_enqueue)); + seq_printf(m, "Ops : dfr=%u rel=%u gc=%u\n", + atomic_read(&fscache_n_op_deferred_release), + atomic_read(&fscache_n_op_release), + atomic_read(&fscache_n_op_gc)); + return 0; +} + +/* + * open "/proc/fs/fscache/stats" allowing provision of a statistical summary + */ +static int fscache_stats_open(struct inode *inode, struct file *file) +{ + return single_open(file, fscache_stats_show, NULL); +} + +const struct file_operations fscache_stats_fops = { + .owner = THIS_MODULE, + .open = fscache_stats_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, +}; diff --git a/include/linux/fscache-cache.h b/include/linux/fscache-cache.h index b2a9a484c4c..84d3532dd3e 100644 --- a/include/linux/fscache-cache.h +++ b/include/linux/fscache-cache.h @@ -29,10 +29,6 @@ struct fscache_cache_ops; struct fscache_object; struct fscache_operation; -#ifdef CONFIG_FSCACHE_PROC -extern struct proc_dir_entry *proc_fscache; -#endif - /* * cache tag definition */ -- cgit v1.2.3-70-g09d2 From a6891645cf2ddd4778096848a864580e7258faba Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:37 +0100 Subject: FS-Cache: Root index definition Add a description of the root index of the cache for later patches to make use of. The root index is owned by FS-Cache itself. When a netfs requests caching facilities, FS-Cache will, if one doesn't already exist, create an entry in the root index with the key being the name of the netfs ("AFS" for example), and the auxiliary data holding the index structure version supplied by the netfs: FSDEF | +-----------+ | | NFS AFS [v=1] [v=1] If an entry with the appropriate name does already exist, the version is compared. If the version is different, the entire subtree from that entry will be discarded and a new entry created. The new entry will be an index, and a cookie referring to it will be passed to the netfs. This is then the root handle by which the netfs accesses the cache. It can create whatever objects it likes in that index, including further indices. Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Al Viro Tested-by: Daire Byrne --- fs/fscache/Makefile | 1 + fs/fscache/fsdef.c | 144 ++++++++++++++++++++++++++++++++++++++++++++++++++ fs/fscache/internal.h | 6 +++ 3 files changed, 151 insertions(+) create mode 100644 fs/fscache/fsdef.c (limited to 'fs') diff --git a/fs/fscache/Makefile b/fs/fscache/Makefile index 1384823a160..bc1f3b9d811 100644 --- a/fs/fscache/Makefile +++ b/fs/fscache/Makefile @@ -3,6 +3,7 @@ # fscache-y := \ + fsdef.o \ main.o fscache-$(CONFIG_PROC_FS) += proc.o diff --git a/fs/fscache/fsdef.c b/fs/fscache/fsdef.c new file mode 100644 index 00000000000..f5b4baee735 --- /dev/null +++ b/fs/fscache/fsdef.c @@ -0,0 +1,144 @@ +/* Filesystem index definition + * + * Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#define FSCACHE_DEBUG_LEVEL CACHE +#include +#include "internal.h" + +static uint16_t fscache_fsdef_netfs_get_key(const void *cookie_netfs_data, + void *buffer, uint16_t bufmax); + +static uint16_t fscache_fsdef_netfs_get_aux(const void *cookie_netfs_data, + void *buffer, uint16_t bufmax); + +static +enum fscache_checkaux fscache_fsdef_netfs_check_aux(void *cookie_netfs_data, + const void *data, + uint16_t datalen); + +/* + * The root index is owned by FS-Cache itself. + * + * When a netfs requests caching facilities, FS-Cache will, if one doesn't + * already exist, create an entry in the root index with the key being the name + * of the netfs ("AFS" for example), and the auxiliary data holding the index + * structure version supplied by the netfs: + * + * FSDEF + * | + * +-----------+ + * | | + * NFS AFS + * [v=1] [v=1] + * + * If an entry with the appropriate name does already exist, the version is + * compared. If the version is different, the entire subtree from that entry + * will be discarded and a new entry created. + * + * The new entry will be an index, and a cookie referring to it will be passed + * to the netfs. This is then the root handle by which the netfs accesses the + * cache. It can create whatever objects it likes in that index, including + * further indices. + */ +static struct fscache_cookie_def fscache_fsdef_index_def = { + .name = ".FS-Cache", + .type = FSCACHE_COOKIE_TYPE_INDEX, +}; + +struct fscache_cookie fscache_fsdef_index = { + .usage = ATOMIC_INIT(1), + .lock = __SPIN_LOCK_UNLOCKED(fscache_fsdef_index.lock), + .backing_objects = HLIST_HEAD_INIT, + .def = &fscache_fsdef_index_def, +}; +EXPORT_SYMBOL(fscache_fsdef_index); + +/* + * Definition of an entry in the root index. Each entry is an index, keyed to + * a specific netfs and only applicable to a particular version of the index + * structure used by that netfs. + */ +struct fscache_cookie_def fscache_fsdef_netfs_def = { + .name = "FSDEF.netfs", + .type = FSCACHE_COOKIE_TYPE_INDEX, + .get_key = fscache_fsdef_netfs_get_key, + .get_aux = fscache_fsdef_netfs_get_aux, + .check_aux = fscache_fsdef_netfs_check_aux, +}; + +/* + * get the key data for an FSDEF index record - this is the name of the netfs + * for which this entry is created + */ +static uint16_t fscache_fsdef_netfs_get_key(const void *cookie_netfs_data, + void *buffer, uint16_t bufmax) +{ + const struct fscache_netfs *netfs = cookie_netfs_data; + unsigned klen; + + _enter("{%s.%u},", netfs->name, netfs->version); + + klen = strlen(netfs->name); + if (klen > bufmax) + return 0; + + memcpy(buffer, netfs->name, klen); + return klen; +} + +/* + * get the auxiliary data for an FSDEF index record - this is the index + * structure version number of the netfs for which this version is created + */ +static uint16_t fscache_fsdef_netfs_get_aux(const void *cookie_netfs_data, + void *buffer, uint16_t bufmax) +{ + const struct fscache_netfs *netfs = cookie_netfs_data; + unsigned dlen; + + _enter("{%s.%u},", netfs->name, netfs->version); + + dlen = sizeof(uint32_t); + if (dlen > bufmax) + return 0; + + memcpy(buffer, &netfs->version, dlen); + return dlen; +} + +/* + * check that the index structure version number stored in the auxiliary data + * matches the one the netfs gave us + */ +static enum fscache_checkaux fscache_fsdef_netfs_check_aux( + void *cookie_netfs_data, + const void *data, + uint16_t datalen) +{ + struct fscache_netfs *netfs = cookie_netfs_data; + uint32_t version; + + _enter("{%s},,%hu", netfs->name, datalen); + + if (datalen != sizeof(version)) { + _leave(" = OBSOLETE [dl=%d v=%zu]", datalen, sizeof(version)); + return FSCACHE_CHECKAUX_OBSOLETE; + } + + memcpy(&version, data, sizeof(version)); + if (version != netfs->version) { + _leave(" = OBSOLETE [ver=%x net=%x]", version, netfs->version); + return FSCACHE_CHECKAUX_OBSOLETE; + } + + _leave(" = OKAY"); + return FSCACHE_CHECKAUX_OKAY; +} diff --git a/fs/fscache/internal.h b/fs/fscache/internal.h index 16f9f1f46e4..4113af8d166 100644 --- a/fs/fscache/internal.h +++ b/fs/fscache/internal.h @@ -27,6 +27,12 @@ #define FSCACHE_MIN_THREADS 4 #define FSCACHE_MAX_THREADS 32 +/* + * fsc-fsdef.c + */ +extern struct fscache_cookie fscache_fsdef_index; +extern struct fscache_cookie_def fscache_fsdef_netfs_def; + /* * fsc-histogram.c */ -- cgit v1.2.3-70-g09d2 From 0e04d4cefcf4d8fbbdb2c50e93ad541582933fd2 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:37 +0100 Subject: FS-Cache: Add cache tag handling Implement two features of FS-Cache: (1) The ability to request and release cache tags - names by which a cache may be known to a netfs, and thus selected for use. (2) An internal function by which a cache is selected by consulting the netfs, if the netfs wishes to be consulted. Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Al Viro Tested-by: Daire Byrne --- fs/fscache/Makefile | 1 + fs/fscache/cache.c | 166 ++++++++++++++++++++++++++++++++++++++++++++++++ fs/fscache/internal.h | 20 ++++++ include/linux/fscache.h | 9 ++- 4 files changed, 195 insertions(+), 1 deletion(-) create mode 100644 fs/fscache/cache.c (limited to 'fs') diff --git a/fs/fscache/Makefile b/fs/fscache/Makefile index bc1f3b9d811..556708bb979 100644 --- a/fs/fscache/Makefile +++ b/fs/fscache/Makefile @@ -3,6 +3,7 @@ # fscache-y := \ + cache.o \ fsdef.o \ main.o diff --git a/fs/fscache/cache.c b/fs/fscache/cache.c new file mode 100644 index 00000000000..1a28df36dd9 --- /dev/null +++ b/fs/fscache/cache.c @@ -0,0 +1,166 @@ +/* FS-Cache cache handling + * + * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#define FSCACHE_DEBUG_LEVEL CACHE +#include +#include +#include "internal.h" + +LIST_HEAD(fscache_cache_list); +DECLARE_RWSEM(fscache_addremove_sem); + +static LIST_HEAD(fscache_cache_tag_list); + +/* + * look up a cache tag + */ +struct fscache_cache_tag *__fscache_lookup_cache_tag(const char *name) +{ + struct fscache_cache_tag *tag, *xtag; + + /* firstly check for the existence of the tag under read lock */ + down_read(&fscache_addremove_sem); + + list_for_each_entry(tag, &fscache_cache_tag_list, link) { + if (strcmp(tag->name, name) == 0) { + atomic_inc(&tag->usage); + up_read(&fscache_addremove_sem); + return tag; + } + } + + up_read(&fscache_addremove_sem); + + /* the tag does not exist - create a candidate */ + xtag = kzalloc(sizeof(*xtag) + strlen(name) + 1, GFP_KERNEL); + if (!xtag) + /* return a dummy tag if out of memory */ + return ERR_PTR(-ENOMEM); + + atomic_set(&xtag->usage, 1); + strcpy(xtag->name, name); + + /* write lock, search again and add if still not present */ + down_write(&fscache_addremove_sem); + + list_for_each_entry(tag, &fscache_cache_tag_list, link) { + if (strcmp(tag->name, name) == 0) { + atomic_inc(&tag->usage); + up_write(&fscache_addremove_sem); + kfree(xtag); + return tag; + } + } + + list_add_tail(&xtag->link, &fscache_cache_tag_list); + up_write(&fscache_addremove_sem); + return xtag; +} + +/* + * release a reference to a cache tag + */ +void __fscache_release_cache_tag(struct fscache_cache_tag *tag) +{ + if (tag != ERR_PTR(-ENOMEM)) { + down_write(&fscache_addremove_sem); + + if (atomic_dec_and_test(&tag->usage)) + list_del_init(&tag->link); + else + tag = NULL; + + up_write(&fscache_addremove_sem); + + kfree(tag); + } +} + +/* + * select a cache in which to store an object + * - the cache addremove semaphore must be at least read-locked by the caller + * - the object will never be an index + */ +struct fscache_cache *fscache_select_cache_for_object( + struct fscache_cookie *cookie) +{ + struct fscache_cache_tag *tag; + struct fscache_object *object; + struct fscache_cache *cache; + + _enter(""); + + if (list_empty(&fscache_cache_list)) { + _leave(" = NULL [no cache]"); + return NULL; + } + + /* we check the parent to determine the cache to use */ + spin_lock(&cookie->lock); + + /* the first in the parent's backing list should be the preferred + * cache */ + if (!hlist_empty(&cookie->backing_objects)) { + object = hlist_entry(cookie->backing_objects.first, + struct fscache_object, cookie_link); + + cache = object->cache; + if (object->state >= FSCACHE_OBJECT_DYING || + test_bit(FSCACHE_IOERROR, &cache->flags)) + cache = NULL; + + spin_unlock(&cookie->lock); + _leave(" = %p [parent]", cache); + return cache; + } + + /* the parent is unbacked */ + if (cookie->def->type != FSCACHE_COOKIE_TYPE_INDEX) { + /* cookie not an index and is unbacked */ + spin_unlock(&cookie->lock); + _leave(" = NULL [cookie ub,ni]"); + return NULL; + } + + spin_unlock(&cookie->lock); + + if (!cookie->def->select_cache) + goto no_preference; + + /* ask the netfs for its preference */ + tag = cookie->def->select_cache(cookie->parent->netfs_data, + cookie->netfs_data); + if (!tag) + goto no_preference; + + if (tag == ERR_PTR(-ENOMEM)) { + _leave(" = NULL [nomem tag]"); + return NULL; + } + + if (!tag->cache) { + _leave(" = NULL [unbacked tag]"); + return NULL; + } + + if (test_bit(FSCACHE_IOERROR, &tag->cache->flags)) + return NULL; + + _leave(" = %p [specific]", tag->cache); + return tag->cache; + +no_preference: + /* netfs has no preference - just select first cache */ + cache = list_entry(fscache_cache_list.next, + struct fscache_cache, link); + _leave(" = %p [first]", cache); + return cache; +} diff --git a/fs/fscache/internal.h b/fs/fscache/internal.h index 4113af8d166..0a2069afa41 100644 --- a/fs/fscache/internal.h +++ b/fs/fscache/internal.h @@ -27,6 +27,15 @@ #define FSCACHE_MIN_THREADS 4 #define FSCACHE_MAX_THREADS 32 +/* + * fsc-cache.c + */ +extern struct list_head fscache_cache_list; +extern struct rw_semaphore fscache_addremove_sem; + +extern struct fscache_cache *fscache_select_cache_for_object( + struct fscache_cookie *); + /* * fsc-fsdef.c */ @@ -168,6 +177,17 @@ extern const struct file_operations fscache_stats_fops; #define fscache_stat(stat) do {} while (0) #endif +/* + * raise an event on an object + * - if the event is not masked for that object, then the object is + * queued for attention by the thread pool. + */ +static inline void fscache_raise_event(struct fscache_object *object, + unsigned event) +{ + BUG(); // TODO +} + /*****************************************************************************/ /* * debug tracing diff --git a/include/linux/fscache.h b/include/linux/fscache.h index feb3b0e0af4..9584c094d69 100644 --- a/include/linux/fscache.h +++ b/include/linux/fscache.h @@ -173,6 +173,8 @@ struct fscache_netfs { * - these are undefined symbols when FS-Cache is not configured and the * optimiser takes care of not using them */ +extern struct fscache_cache_tag *__fscache_lookup_cache_tag(const char *); +extern void __fscache_release_cache_tag(struct fscache_cache_tag *); /** * fscache_register_netfs - Register a filesystem as desiring caching services @@ -218,7 +220,10 @@ void fscache_unregister_netfs(struct fscache_netfs *netfs) static inline struct fscache_cache_tag *fscache_lookup_cache_tag(const char *name) { - return NULL; + if (fscache_available()) + return __fscache_lookup_cache_tag(name); + else + return NULL; } /** @@ -233,6 +238,8 @@ struct fscache_cache_tag *fscache_lookup_cache_tag(const char *name) static inline void fscache_release_cache_tag(struct fscache_cache_tag *tag) { + if (fscache_available()) + __fscache_release_cache_tag(tag); } /** -- cgit v1.2.3-70-g09d2 From 4c515dd47ab41be3f89e757d441661795470b376 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:37 +0100 Subject: FS-Cache: Add cache management Implement the entry points by which a cache backend may initialise, add, declare an error upon and withdraw a cache. Further, an object is created in sysfs under which each cache added will get an object created: /sys/fs/fscache// All of this is described in Documentation/filesystems/caching/backend-api.txt added by a previous patch. Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Al Viro Tested-by: Daire Byrne --- fs/fscache/cache.c | 249 +++++++++++++++++++++++++++++++++++++++++++++++++++++ fs/fscache/main.c | 7 ++ 2 files changed, 256 insertions(+) (limited to 'fs') diff --git a/fs/fscache/cache.c b/fs/fscache/cache.c index 1a28df36dd9..355172f785f 100644 --- a/fs/fscache/cache.c +++ b/fs/fscache/cache.c @@ -16,6 +16,8 @@ LIST_HEAD(fscache_cache_list); DECLARE_RWSEM(fscache_addremove_sem); +DECLARE_WAIT_QUEUE_HEAD(fscache_cache_cleared_wq); +EXPORT_SYMBOL(fscache_cache_cleared_wq); static LIST_HEAD(fscache_cache_tag_list); @@ -164,3 +166,250 @@ no_preference: _leave(" = %p [first]", cache); return cache; } + +/** + * fscache_init_cache - Initialise a cache record + * @cache: The cache record to be initialised + * @ops: The cache operations to be installed in that record + * @idfmt: Format string to define identifier + * @...: sprintf-style arguments + * + * Initialise a record of a cache and fill in the name. + * + * See Documentation/filesystems/caching/backend-api.txt for a complete + * description. + */ +void fscache_init_cache(struct fscache_cache *cache, + const struct fscache_cache_ops *ops, + const char *idfmt, + ...) +{ + va_list va; + + memset(cache, 0, sizeof(*cache)); + + cache->ops = ops; + + va_start(va, idfmt); + vsnprintf(cache->identifier, sizeof(cache->identifier), idfmt, va); + va_end(va); + + INIT_WORK(&cache->op_gc, NULL); + INIT_LIST_HEAD(&cache->link); + INIT_LIST_HEAD(&cache->object_list); + INIT_LIST_HEAD(&cache->op_gc_list); + spin_lock_init(&cache->object_list_lock); + spin_lock_init(&cache->op_gc_list_lock); +} +EXPORT_SYMBOL(fscache_init_cache); + +/** + * fscache_add_cache - Declare a cache as being open for business + * @cache: The record describing the cache + * @ifsdef: The record of the cache object describing the top-level index + * @tagname: The tag describing this cache + * + * Add a cache to the system, making it available for netfs's to use. + * + * See Documentation/filesystems/caching/backend-api.txt for a complete + * description. + */ +int fscache_add_cache(struct fscache_cache *cache, + struct fscache_object *ifsdef, + const char *tagname) +{ + struct fscache_cache_tag *tag; + + BUG_ON(!cache->ops); + BUG_ON(!ifsdef); + + cache->flags = 0; + ifsdef->event_mask = ULONG_MAX & ~(1 << FSCACHE_OBJECT_EV_CLEARED); + ifsdef->state = FSCACHE_OBJECT_ACTIVE; + + if (!tagname) + tagname = cache->identifier; + + BUG_ON(!tagname[0]); + + _enter("{%s.%s},,%s", cache->ops->name, cache->identifier, tagname); + + /* we use the cache tag to uniquely identify caches */ + tag = __fscache_lookup_cache_tag(tagname); + if (IS_ERR(tag)) + goto nomem; + + if (test_and_set_bit(FSCACHE_TAG_RESERVED, &tag->flags)) + goto tag_in_use; + + cache->kobj = kobject_create_and_add(tagname, fscache_root); + if (!cache->kobj) + goto error; + + ifsdef->cookie = &fscache_fsdef_index; + ifsdef->cache = cache; + cache->fsdef = ifsdef; + + down_write(&fscache_addremove_sem); + + tag->cache = cache; + cache->tag = tag; + + /* add the cache to the list */ + list_add(&cache->link, &fscache_cache_list); + + /* add the cache's netfs definition index object to the cache's + * list */ + spin_lock(&cache->object_list_lock); + list_add_tail(&ifsdef->cache_link, &cache->object_list); + spin_unlock(&cache->object_list_lock); + + /* add the cache's netfs definition index object to the top level index + * cookie as a known backing object */ + spin_lock(&fscache_fsdef_index.lock); + + hlist_add_head(&ifsdef->cookie_link, + &fscache_fsdef_index.backing_objects); + + atomic_inc(&fscache_fsdef_index.usage); + + /* done */ + spin_unlock(&fscache_fsdef_index.lock); + up_write(&fscache_addremove_sem); + + printk(KERN_NOTICE "FS-Cache: Cache \"%s\" added (type %s)\n", + cache->tag->name, cache->ops->name); + kobject_uevent(cache->kobj, KOBJ_ADD); + + _leave(" = 0 [%s]", cache->identifier); + return 0; + +tag_in_use: + printk(KERN_ERR "FS-Cache: Cache tag '%s' already in use\n", tagname); + __fscache_release_cache_tag(tag); + _leave(" = -EXIST"); + return -EEXIST; + +error: + __fscache_release_cache_tag(tag); + _leave(" = -EINVAL"); + return -EINVAL; + +nomem: + _leave(" = -ENOMEM"); + return -ENOMEM; +} +EXPORT_SYMBOL(fscache_add_cache); + +/** + * fscache_io_error - Note a cache I/O error + * @cache: The record describing the cache + * + * Note that an I/O error occurred in a cache and that it should no longer be + * used for anything. This also reports the error into the kernel log. + * + * See Documentation/filesystems/caching/backend-api.txt for a complete + * description. + */ +void fscache_io_error(struct fscache_cache *cache) +{ + set_bit(FSCACHE_IOERROR, &cache->flags); + + printk(KERN_ERR "FS-Cache: Cache %s stopped due to I/O error\n", + cache->ops->name); +} +EXPORT_SYMBOL(fscache_io_error); + +/* + * request withdrawal of all the objects in a cache + * - all the objects being withdrawn are moved onto the supplied list + */ +static void fscache_withdraw_all_objects(struct fscache_cache *cache, + struct list_head *dying_objects) +{ + struct fscache_object *object; + + spin_lock(&cache->object_list_lock); + + while (!list_empty(&cache->object_list)) { + object = list_entry(cache->object_list.next, + struct fscache_object, cache_link); + list_move_tail(&object->cache_link, dying_objects); + + _debug("withdraw %p", object->cookie); + + spin_lock(&object->lock); + spin_unlock(&cache->object_list_lock); + fscache_raise_event(object, FSCACHE_OBJECT_EV_WITHDRAW); + spin_unlock(&object->lock); + + cond_resched(); + spin_lock(&cache->object_list_lock); + } + + spin_unlock(&cache->object_list_lock); +} + +/** + * fscache_withdraw_cache - Withdraw a cache from the active service + * @cache: The record describing the cache + * + * Withdraw a cache from service, unbinding all its cache objects from the + * netfs cookies they're currently representing. + * + * See Documentation/filesystems/caching/backend-api.txt for a complete + * description. + */ +void fscache_withdraw_cache(struct fscache_cache *cache) +{ + LIST_HEAD(dying_objects); + + _enter(""); + + printk(KERN_NOTICE "FS-Cache: Withdrawing cache \"%s\"\n", + cache->tag->name); + + /* make the cache unavailable for cookie acquisition */ + if (test_and_set_bit(FSCACHE_CACHE_WITHDRAWN, &cache->flags)) + BUG(); + + down_write(&fscache_addremove_sem); + list_del_init(&cache->link); + cache->tag->cache = NULL; + up_write(&fscache_addremove_sem); + + /* make sure all pages pinned by operations on behalf of the netfs are + * written to disk */ + cache->ops->sync_cache(cache); + + /* dissociate all the netfs pages backed by this cache from the block + * mappings in the cache */ + cache->ops->dissociate_pages(cache); + + /* we now have to destroy all the active objects pertaining to this + * cache - which we do by passing them off to thread pool to be + * disposed of */ + _debug("destroy"); + + fscache_withdraw_all_objects(cache, &dying_objects); + + /* wait for all extant objects to finish their outstanding operations + * and go away */ + _debug("wait for finish"); + wait_event(fscache_cache_cleared_wq, + atomic_read(&cache->object_count) == 0); + _debug("wait for clearance"); + wait_event(fscache_cache_cleared_wq, + list_empty(&cache->object_list)); + _debug("cleared"); + ASSERT(list_empty(&dying_objects)); + + kobject_put(cache->kobj); + + clear_bit(FSCACHE_TAG_RESERVED, &cache->tag->flags); + fscache_release_cache_tag(cache->tag); + cache->tag = NULL; + + _leave(""); +} +EXPORT_SYMBOL(fscache_withdraw_cache); diff --git a/fs/fscache/main.c b/fs/fscache/main.c index 7c734b7fb18..c2f3e637725 100644 --- a/fs/fscache/main.c +++ b/fs/fscache/main.c @@ -56,9 +56,15 @@ static int __init fscache_init(void) if (ret < 0) goto error_proc; + fscache_root = kobject_create_and_add("fscache", kernel_kobj); + if (!fscache_root) + goto error_kobj; + printk(KERN_NOTICE "FS-Cache: Loaded\n"); return 0; +error_kobj: + fscache_proc_cleanup(); error_proc: slow_work_unregister_user(); error_slow_work: @@ -74,6 +80,7 @@ static void __exit fscache_exit(void) { _enter(""); + kobject_put(fscache_root); fscache_proc_cleanup(); slow_work_unregister_user(); printk(KERN_NOTICE "FS-Cache: Unloaded\n"); -- cgit v1.2.3-70-g09d2 From 955d00917f0c094e0f2fb88df967e980ab66b8ca Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:38 +0100 Subject: FS-Cache: Provide a slab for cookie allocation Provide a slab from which can be allocated the FS-Cache cookies that will be presented to the netfs. Also provide a slab constructor and a function to recursively discard a cookie and its ancestor chain. Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Al Viro Tested-by: Daire Byrne --- fs/fscache/Makefile | 1 + fs/fscache/cookie.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++++++ fs/fscache/internal.h | 8 ++++++++ fs/fscache/main.c | 15 ++++++++++++++ 4 files changed, 80 insertions(+) create mode 100644 fs/fscache/cookie.c (limited to 'fs') diff --git a/fs/fscache/Makefile b/fs/fscache/Makefile index 556708bb979..f88ac1764ce 100644 --- a/fs/fscache/Makefile +++ b/fs/fscache/Makefile @@ -4,6 +4,7 @@ fscache-y := \ cache.o \ + cookie.o \ fsdef.o \ main.o diff --git a/fs/fscache/cookie.c b/fs/fscache/cookie.c new file mode 100644 index 00000000000..47fd75b832e --- /dev/null +++ b/fs/fscache/cookie.c @@ -0,0 +1,56 @@ +/* netfs cookie management + * + * Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#define FSCACHE_DEBUG_LEVEL COOKIE +#include +#include +#include "internal.h" + +struct kmem_cache *fscache_cookie_jar; + +/* + * initialise an cookie jar slab element prior to any use + */ +void fscache_cookie_init_once(void *_cookie) +{ + struct fscache_cookie *cookie = _cookie; + + memset(cookie, 0, sizeof(*cookie)); + spin_lock_init(&cookie->lock); + INIT_HLIST_HEAD(&cookie->backing_objects); +} + +/* + * destroy a cookie + */ +void __fscache_cookie_put(struct fscache_cookie *cookie) +{ + struct fscache_cookie *parent; + + _enter("%p", cookie); + + for (;;) { + _debug("FREE COOKIE %p", cookie); + parent = cookie->parent; + BUG_ON(!hlist_empty(&cookie->backing_objects)); + kmem_cache_free(fscache_cookie_jar, cookie); + + if (!parent) + break; + + cookie = parent; + BUG_ON(atomic_read(&cookie->usage) <= 0); + if (!atomic_dec_and_test(&cookie->usage)) + break; + } + + _leave(""); +} diff --git a/fs/fscache/internal.h b/fs/fscache/internal.h index 0a2069afa41..4c6ba561e96 100644 --- a/fs/fscache/internal.h +++ b/fs/fscache/internal.h @@ -36,6 +36,14 @@ extern struct rw_semaphore fscache_addremove_sem; extern struct fscache_cache *fscache_select_cache_for_object( struct fscache_cookie *); +/* + * fsc-cookie.c + */ +extern struct kmem_cache *fscache_cookie_jar; + +extern void fscache_cookie_init_once(void *); +extern void __fscache_cookie_put(struct fscache_cookie *); + /* * fsc-fsdef.c */ diff --git a/fs/fscache/main.c b/fs/fscache/main.c index c2f3e637725..48b79d2deac 100644 --- a/fs/fscache/main.c +++ b/fs/fscache/main.c @@ -56,6 +56,18 @@ static int __init fscache_init(void) if (ret < 0) goto error_proc; + fscache_cookie_jar = kmem_cache_create("fscache_cookie_jar", + sizeof(struct fscache_cookie), + 0, + 0, + fscache_cookie_init_once); + if (!fscache_cookie_jar) { + printk(KERN_NOTICE + "FS-Cache: Failed to allocate a cookie jar\n"); + ret = -ENOMEM; + goto error_cookie_jar; + } + fscache_root = kobject_create_and_add("fscache", kernel_kobj); if (!fscache_root) goto error_kobj; @@ -64,6 +76,8 @@ static int __init fscache_init(void) return 0; error_kobj: + kmem_cache_destroy(fscache_cookie_jar); +error_cookie_jar: fscache_proc_cleanup(); error_proc: slow_work_unregister_user(); @@ -81,6 +95,7 @@ static void __exit fscache_exit(void) _enter(""); kobject_put(fscache_root); + kmem_cache_destroy(fscache_cookie_jar); fscache_proc_cleanup(); slow_work_unregister_user(); printk(KERN_NOTICE "FS-Cache: Unloaded\n"); -- cgit v1.2.3-70-g09d2 From 726dd7ff10c217dd74329c94643dc8ebea27334b Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:38 +0100 Subject: FS-Cache: Add netfs registration Add functions to register and unregister a network filesystem or other client of the FS-Cache service. This allocates and releases the cookie representing the top-level index for a netfs, and makes it available to the netfs. If the FS-Cache facility is disabled, then the calls are optimised away at compile time. Note that whilst this patch may appear to work with FS-Cache enabled and a netfs attempting to use it, it will leak the cookie it allocates for the netfs as fscache_relinquish_cookie() is implemented in a later patch. This will cause the slab code to emit a warning when the module is removed. Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Al Viro Tested-by: Daire Byrne --- fs/fscache/Makefile | 3 +- fs/fscache/netfs.c | 103 ++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/fscache.h | 9 ++++- 3 files changed, 113 insertions(+), 2 deletions(-) create mode 100644 fs/fscache/netfs.c (limited to 'fs') diff --git a/fs/fscache/Makefile b/fs/fscache/Makefile index f88ac1764ce..ecf6946eaeb 100644 --- a/fs/fscache/Makefile +++ b/fs/fscache/Makefile @@ -6,7 +6,8 @@ fscache-y := \ cache.o \ cookie.o \ fsdef.o \ - main.o + main.o \ + netfs.o fscache-$(CONFIG_PROC_FS) += proc.o fscache-$(CONFIG_FSCACHE_STATS) += stats.o diff --git a/fs/fscache/netfs.c b/fs/fscache/netfs.c new file mode 100644 index 00000000000..e028b8eb1c4 --- /dev/null +++ b/fs/fscache/netfs.c @@ -0,0 +1,103 @@ +/* FS-Cache netfs (client) registration + * + * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#define FSCACHE_DEBUG_LEVEL COOKIE +#include +#include +#include "internal.h" + +static LIST_HEAD(fscache_netfs_list); + +/* + * register a network filesystem for caching + */ +int __fscache_register_netfs(struct fscache_netfs *netfs) +{ + struct fscache_netfs *ptr; + int ret; + + _enter("{%s}", netfs->name); + + INIT_LIST_HEAD(&netfs->link); + + /* allocate a cookie for the primary index */ + netfs->primary_index = + kmem_cache_zalloc(fscache_cookie_jar, GFP_KERNEL); + + if (!netfs->primary_index) { + _leave(" = -ENOMEM"); + return -ENOMEM; + } + + /* initialise the primary index cookie */ + atomic_set(&netfs->primary_index->usage, 1); + atomic_set(&netfs->primary_index->n_children, 0); + + netfs->primary_index->def = &fscache_fsdef_netfs_def; + netfs->primary_index->parent = &fscache_fsdef_index; + netfs->primary_index->netfs_data = netfs; + + atomic_inc(&netfs->primary_index->parent->usage); + atomic_inc(&netfs->primary_index->parent->n_children); + + spin_lock_init(&netfs->primary_index->lock); + INIT_HLIST_HEAD(&netfs->primary_index->backing_objects); + + /* check the netfs type is not already present */ + down_write(&fscache_addremove_sem); + + ret = -EEXIST; + list_for_each_entry(ptr, &fscache_netfs_list, link) { + if (strcmp(ptr->name, netfs->name) == 0) + goto already_registered; + } + + list_add(&netfs->link, &fscache_netfs_list); + ret = 0; + + printk(KERN_NOTICE "FS-Cache: Netfs '%s' registered for caching\n", + netfs->name); + +already_registered: + up_write(&fscache_addremove_sem); + + if (ret < 0) { + netfs->primary_index->parent = NULL; + __fscache_cookie_put(netfs->primary_index); + netfs->primary_index = NULL; + } + + _leave(" = %d", ret); + return ret; +} +EXPORT_SYMBOL(__fscache_register_netfs); + +/* + * unregister a network filesystem from the cache + * - all cookies must have been released first + */ +void __fscache_unregister_netfs(struct fscache_netfs *netfs) +{ + _enter("{%s.%u}", netfs->name, netfs->version); + + down_write(&fscache_addremove_sem); + + list_del(&netfs->link); + fscache_relinquish_cookie(netfs->primary_index, 0); + + up_write(&fscache_addremove_sem); + + printk(KERN_NOTICE "FS-Cache: Netfs '%s' unregistered from caching\n", + netfs->name); + + _leave(""); +} +EXPORT_SYMBOL(__fscache_unregister_netfs); diff --git a/include/linux/fscache.h b/include/linux/fscache.h index 9584c094d69..b195c2e1ef6 100644 --- a/include/linux/fscache.h +++ b/include/linux/fscache.h @@ -173,6 +173,8 @@ struct fscache_netfs { * - these are undefined symbols when FS-Cache is not configured and the * optimiser takes care of not using them */ +extern int __fscache_register_netfs(struct fscache_netfs *); +extern void __fscache_unregister_netfs(struct fscache_netfs *); extern struct fscache_cache_tag *__fscache_lookup_cache_tag(const char *); extern void __fscache_release_cache_tag(struct fscache_cache_tag *); @@ -188,7 +190,10 @@ extern void __fscache_release_cache_tag(struct fscache_cache_tag *); static inline int fscache_register_netfs(struct fscache_netfs *netfs) { - return 0; + if (fscache_available()) + return __fscache_register_netfs(netfs); + else + return 0; } /** @@ -205,6 +210,8 @@ int fscache_register_netfs(struct fscache_netfs *netfs) static inline void fscache_unregister_netfs(struct fscache_netfs *netfs) { + if (fscache_available()) + __fscache_unregister_netfs(netfs); } /** -- cgit v1.2.3-70-g09d2 From 2868cbea72dc89ae0eb17693596b1dedaafff1c5 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:38 +0100 Subject: FS-Cache: Bit waiting helpers Add helpers for use with wait_on_bit(). Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Al Viro Tested-by: Daire Byrne --- fs/fscache/internal.h | 3 +++ fs/fscache/main.c | 20 ++++++++++++++++++++ 2 files changed, 23 insertions(+) (limited to 'fs') diff --git a/fs/fscache/internal.h b/fs/fscache/internal.h index 4c6ba561e96..16389942a54 100644 --- a/fs/fscache/internal.h +++ b/fs/fscache/internal.h @@ -82,6 +82,9 @@ extern unsigned fscache_defer_create; extern unsigned fscache_debug; extern struct kobject *fscache_root; +extern int fscache_wait_bit(void *); +extern int fscache_wait_bit_interruptible(void *); + /* * fsc-proc.c */ diff --git a/fs/fscache/main.c b/fs/fscache/main.c index 48b79d2deac..4de41b59749 100644 --- a/fs/fscache/main.c +++ b/fs/fscache/main.c @@ -102,3 +102,23 @@ static void __exit fscache_exit(void) } module_exit(fscache_exit); + +/* + * wait_on_bit() sleep function for uninterruptible waiting + */ +int fscache_wait_bit(void *flags) +{ + schedule(); + return 0; +} +EXPORT_SYMBOL(fscache_wait_bit); + +/* + * wait_on_bit() sleep function for interruptible waiting + */ +int fscache_wait_bit_interruptible(void *flags) +{ + schedule(); + return signal_pending(current); +} +EXPORT_SYMBOL(fscache_wait_bit_interruptible); -- cgit v1.2.3-70-g09d2 From 36c9559022850f919269564a74bf17fdabf4bb30 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:38 +0100 Subject: FS-Cache: Object management state machine Implement the cache object management state machine. The following documentation is added to illuminate the working of this state machine. It will also be added as: Documentation/filesystems/caching/object.txt ==================================================== IN-KERNEL CACHE OBJECT REPRESENTATION AND MANAGEMENT ==================================================== ============== REPRESENTATION ============== FS-Cache maintains an in-kernel representation of each object that a netfs is currently interested in. Such objects are represented by the fscache_cookie struct and are referred to as cookies. FS-Cache also maintains a separate in-kernel representation of the objects that a cache backend is currently actively caching. Such objects are represented by the fscache_object struct. The cache backends allocate these upon request, and are expected to embed them in their own representations. These are referred to as objects. There is a 1:N relationship between cookies and objects. A cookie may be represented by multiple objects - an index may exist in more than one cache - or even by no objects (it may not be cached). Furthermore, both cookies and objects are hierarchical. The two hierarchies correspond, but the cookies tree is a superset of the union of the object trees of multiple caches: NETFS INDEX TREE : CACHE 1 : CACHE 2 : : : +-----------+ : +----------->| IObject | : +-----------+ | : +-----------+ : | ICookie |-------+ : | : +-----------+ | : | : +-----------+ | +------------------------------>| IObject | | : | : +-----------+ | : V : | | : +-----------+ : | V +----------->| IObject | : | +-----------+ | : +-----------+ : | | ICookie |-------+ : | : V +-----------+ | : | : +-----------+ | +------------------------------>| IObject | +-----+-----+ : | : +-----------+ | | : | : | V | : V : | +-----------+ | : +-----------+ : | | ICookie |------------------------->| IObject | : | +-----------+ | : +-----------+ : | | V : | : V | +-----------+ : | : +-----------+ | | ICookie |-------------------------------->| IObject | | +-----------+ : | : +-----------+ V | : V : | +-----------+ | : +-----------+ : | | DCookie |------------------------->| DObject | : | +-----------+ | : +-----------+ : | | : : | +-------+-------+ : : | | | : : | V V : : V +-----------+ +-----------+ : : +-----------+ | DCookie | | DCookie |------------------------>| DObject | +-----------+ +-----------+ : : +-----------+ : : In the above illustration, ICookie and IObject represent indices and DCookie and DObject represent data storage objects. Indices may have representation in multiple caches, but currently, non-index objects may not. Objects of any type may also be entirely unrepresented. As far as the netfs API goes, the netfs is only actually permitted to see pointers to the cookies. The cookies themselves and any objects attached to those cookies are hidden from it. =============================== OBJECT MANAGEMENT STATE MACHINE =============================== Within FS-Cache, each active object is managed by its own individual state machine. The state for an object is kept in the fscache_object struct, in object->state. A cookie may point to a set of objects that are in different states. Each state has an action associated with it that is invoked when the machine wakes up in that state. There are four logical sets of states: (1) Preparation: states that wait for the parent objects to become ready. The representations are hierarchical, and it is expected that an object must be created or accessed with respect to its parent object. (2) Initialisation: states that perform lookups in the cache and validate what's found and that create on disk any missing metadata. (3) Normal running: states that allow netfs operations on objects to proceed and that update the state of objects. (4) Termination: states that detach objects from their netfs cookies, that delete objects from disk, that handle disk and system errors and that free up in-memory resources. In most cases, transitioning between states is in response to signalled events. When a state has finished processing, it will usually set the mask of events in which it is interested (object->event_mask) and relinquish the worker thread. Then when an event is raised (by calling fscache_raise_event()), if the event is not masked, the object will be queued for processing (by calling fscache_enqueue_object()). PROVISION OF CPU TIME --------------------- The work to be done by the various states is given CPU time by the threads of the slow work facility (see Documentation/slow-work.txt). This is used in preference to the workqueue facility because: (1) Threads may be completely occupied for very long periods of time by a particular work item. These state actions may be doing sequences of synchronous, journalled disk accesses (lookup, mkdir, create, setxattr, getxattr, truncate, unlink, rmdir, rename). (2) Threads may do little actual work, but may rather spend a lot of time sleeping on I/O. This means that single-threaded and 1-per-CPU-threaded workqueues don't necessarily have the right numbers of threads. LOCKING SIMPLIFICATION ---------------------- Because only one worker thread may be operating on any particular object's state machine at once, this simplifies the locking, particularly with respect to disconnecting the netfs's representation of a cache object (fscache_cookie) from the cache backend's representation (fscache_object) - which may be requested from either end. ================= THE SET OF STATES ================= The object state machine has a set of states that it can be in. There are preparation states in which the object sets itself up and waits for its parent object to transit to a state that allows access to its children: (1) State FSCACHE_OBJECT_INIT. Initialise the object and wait for the parent object to become active. In the cache, it is expected that it will not be possible to look an object up from the parent object, until that parent object itself has been looked up. There are initialisation states in which the object sets itself up and accesses disk for the object metadata: (2) State FSCACHE_OBJECT_LOOKING_UP. Look up the object on disk, using the parent as a starting point. FS-Cache expects the cache backend to probe the cache to see whether this object is represented there, and if it is, to see if it's valid (coherency management). The cache should call fscache_object_lookup_negative() to indicate lookup failure for whatever reason, and should call fscache_obtained_object() to indicate success. At the completion of lookup, FS-Cache will let the netfs go ahead with read operations, no matter whether the file is yet cached. If not yet cached, read operations will be immediately rejected with ENODATA until the first known page is uncached - as to that point there can be no data to be read out of the cache for that file that isn't currently also held in the pagecache. (3) State FSCACHE_OBJECT_CREATING. Create an object on disk, using the parent as a starting point. This happens if the lookup failed to find the object, or if the object's coherency data indicated what's on disk is out of date. In this state, FS-Cache expects the cache to create The cache should call fscache_obtained_object() if creation completes successfully, fscache_object_lookup_negative() otherwise. At the completion of creation, FS-Cache will start processing write operations the netfs has queued for an object. If creation failed, the write ops will be transparently discarded, and nothing recorded in the cache. There are some normal running states in which the object spends its time servicing netfs requests: (4) State FSCACHE_OBJECT_AVAILABLE. A transient state in which pending operations are started, child objects are permitted to advance from FSCACHE_OBJECT_INIT state, and temporary lookup data is freed. (5) State FSCACHE_OBJECT_ACTIVE. The normal running state. In this state, requests the netfs makes will be passed on to the cache. (6) State FSCACHE_OBJECT_UPDATING. The state machine comes here to update the object in the cache from the netfs's records. This involves updating the auxiliary data that is used to maintain coherency. And there are terminal states in which an object cleans itself up, deallocates memory and potentially deletes stuff from disk: (7) State FSCACHE_OBJECT_LC_DYING. The object comes here if it is dying because of a lookup or creation error. This would be due to a disk error or system error of some sort. Temporary data is cleaned up, and the parent is released. (8) State FSCACHE_OBJECT_DYING. The object comes here if it is dying due to an error, because its parent cookie has been relinquished by the netfs or because the cache is being withdrawn. Any child objects waiting on this one are given CPU time so that they too can destroy themselves. This object waits for all its children to go away before advancing to the next state. (9) State FSCACHE_OBJECT_ABORT_INIT. The object comes to this state if it was waiting on its parent in FSCACHE_OBJECT_INIT, but its parent died. The object will destroy itself so that the parent may proceed from the FSCACHE_OBJECT_DYING state. (10) State FSCACHE_OBJECT_RELEASING. (11) State FSCACHE_OBJECT_RECYCLING. The object comes to one of these two states when dying once it is rid of all its children, if it is dying because the netfs relinquished its cookie. In the first state, the cached data is expected to persist, and in the second it will be deleted. (12) State FSCACHE_OBJECT_WITHDRAWING. The object transits to this state if the cache decides it wants to withdraw the object from service, perhaps to make space, but also due to error or just because the whole cache is being withdrawn. (13) State FSCACHE_OBJECT_DEAD. The object transits to this state when the in-memory object record is ready to be deleted. The object processor shouldn't ever see an object in this state. THE SET OF EVENTS ----------------- There are a number of events that can be raised to an object state machine: (*) FSCACHE_OBJECT_EV_UPDATE The netfs requested that an object be updated. The state machine will ask the cache backend to update the object, and the cache backend will ask the netfs for details of the change through its cookie definition ops. (*) FSCACHE_OBJECT_EV_CLEARED This is signalled in two circumstances: (a) when an object's last child object is dropped and (b) when the last operation outstanding on an object is completed. This is used to proceed from the dying state. (*) FSCACHE_OBJECT_EV_ERROR This is signalled when an I/O error occurs during the processing of some object. (*) FSCACHE_OBJECT_EV_RELEASE (*) FSCACHE_OBJECT_EV_RETIRE These are signalled when the netfs relinquishes a cookie it was using. The event selected depends on whether the netfs asks for the backing object to be retired (deleted) or retained. (*) FSCACHE_OBJECT_EV_WITHDRAW This is signalled when the cache backend wants to withdraw an object. This means that the object will have to be detached from the netfs's cookie. Because the withdrawing releasing/retiring events are all handled by the object state machine, it doesn't matter if there's a collision with both ends trying to sever the connection at the same time. The state machine can just pick which one it wants to honour, and that effects the other. Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Al Viro Tested-by: Daire Byrne --- Documentation/filesystems/caching/fscache.txt | 5 + Documentation/filesystems/caching/object.txt | 313 ++++++++++ fs/fscache/Makefile | 3 +- fs/fscache/internal.h | 26 +- fs/fscache/object.c | 810 ++++++++++++++++++++++++++ 5 files changed, 1155 insertions(+), 2 deletions(-) create mode 100644 Documentation/filesystems/caching/object.txt create mode 100644 fs/fscache/object.c (limited to 'fs') diff --git a/Documentation/filesystems/caching/fscache.txt b/Documentation/filesystems/caching/fscache.txt index 0a751f3c2c7..9e94b9491d8 100644 --- a/Documentation/filesystems/caching/fscache.txt +++ b/Documentation/filesystems/caching/fscache.txt @@ -188,6 +188,11 @@ The cache backend API to FS-Cache can be found in: Documentation/filesystems/caching/backend-api.txt +A description of the internal representations and object state machine can be +found in: + + Documentation/filesystems/caching/object.txt + ======================= STATISTICAL INFORMATION diff --git a/Documentation/filesystems/caching/object.txt b/Documentation/filesystems/caching/object.txt new file mode 100644 index 00000000000..e8b0a35d8fe --- /dev/null +++ b/Documentation/filesystems/caching/object.txt @@ -0,0 +1,313 @@ + ==================================================== + IN-KERNEL CACHE OBJECT REPRESENTATION AND MANAGEMENT + ==================================================== + +By: David Howells + +Contents: + + (*) Representation + + (*) Object management state machine. + + - Provision of cpu time. + - Locking simplification. + + (*) The set of states. + + (*) The set of events. + + +============== +REPRESENTATION +============== + +FS-Cache maintains an in-kernel representation of each object that a netfs is +currently interested in. Such objects are represented by the fscache_cookie +struct and are referred to as cookies. + +FS-Cache also maintains a separate in-kernel representation of the objects that +a cache backend is currently actively caching. Such objects are represented by +the fscache_object struct. The cache backends allocate these upon request, and +are expected to embed them in their own representations. These are referred to +as objects. + +There is a 1:N relationship between cookies and objects. A cookie may be +represented by multiple objects - an index may exist in more than one cache - +or even by no objects (it may not be cached). + +Furthermore, both cookies and objects are hierarchical. The two hierarchies +correspond, but the cookies tree is a superset of the union of the object trees +of multiple caches: + + NETFS INDEX TREE : CACHE 1 : CACHE 2 + : : + : +-----------+ : + +----------->| IObject | : + +-----------+ | : +-----------+ : + | ICookie |-------+ : | : + +-----------+ | : | : +-----------+ + | +------------------------------>| IObject | + | : | : +-----------+ + | : V : | + | : +-----------+ : | + V +----------->| IObject | : | + +-----------+ | : +-----------+ : | + | ICookie |-------+ : | : V + +-----------+ | : | : +-----------+ + | +------------------------------>| IObject | + +-----+-----+ : | : +-----------+ + | | : | : | + V | : V : | + +-----------+ | : +-----------+ : | + | ICookie |------------------------->| IObject | : | + +-----------+ | : +-----------+ : | + | V : | : V + | +-----------+ : | : +-----------+ + | | ICookie |-------------------------------->| IObject | + | +-----------+ : | : +-----------+ + V | : V : | + +-----------+ | : +-----------+ : | + | DCookie |------------------------->| DObject | : | + +-----------+ | : +-----------+ : | + | : : | + +-------+-------+ : : | + | | : : | + V V : : V + +-----------+ +-----------+ : : +-----------+ + | DCookie | | DCookie |------------------------>| DObject | + +-----------+ +-----------+ : : +-----------+ + : : + +In the above illustration, ICookie and IObject represent indices and DCookie +and DObject represent data storage objects. Indices may have representation in +multiple caches, but currently, non-index objects may not. Objects of any type +may also be entirely unrepresented. + +As far as the netfs API goes, the netfs is only actually permitted to see +pointers to the cookies. The cookies themselves and any objects attached to +those cookies are hidden from it. + + +=============================== +OBJECT MANAGEMENT STATE MACHINE +=============================== + +Within FS-Cache, each active object is managed by its own individual state +machine. The state for an object is kept in the fscache_object struct, in +object->state. A cookie may point to a set of objects that are in different +states. + +Each state has an action associated with it that is invoked when the machine +wakes up in that state. There are four logical sets of states: + + (1) Preparation: states that wait for the parent objects to become ready. The + representations are hierarchical, and it is expected that an object must + be created or accessed with respect to its parent object. + + (2) Initialisation: states that perform lookups in the cache and validate + what's found and that create on disk any missing metadata. + + (3) Normal running: states that allow netfs operations on objects to proceed + and that update the state of objects. + + (4) Termination: states that detach objects from their netfs cookies, that + delete objects from disk, that handle disk and system errors and that free + up in-memory resources. + + +In most cases, transitioning between states is in response to signalled events. +When a state has finished processing, it will usually set the mask of events in +which it is interested (object->event_mask) and relinquish the worker thread. +Then when an event is raised (by calling fscache_raise_event()), if the event +is not masked, the object will be queued for processing (by calling +fscache_enqueue_object()). + + +PROVISION OF CPU TIME +--------------------- + +The work to be done by the various states is given CPU time by the threads of +the slow work facility (see Documentation/slow-work.txt). This is used in +preference to the workqueue facility because: + + (1) Threads may be completely occupied for very long periods of time by a + particular work item. These state actions may be doing sequences of + synchronous, journalled disk accesses (lookup, mkdir, create, setxattr, + getxattr, truncate, unlink, rmdir, rename). + + (2) Threads may do little actual work, but may rather spend a lot of time + sleeping on I/O. This means that single-threaded and 1-per-CPU-threaded + workqueues don't necessarily have the right numbers of threads. + + +LOCKING SIMPLIFICATION +---------------------- + +Because only one worker thread may be operating on any particular object's +state machine at once, this simplifies the locking, particularly with respect +to disconnecting the netfs's representation of a cache object (fscache_cookie) +from the cache backend's representation (fscache_object) - which may be +requested from either end. + + +================= +THE SET OF STATES +================= + +The object state machine has a set of states that it can be in. There are +preparation states in which the object sets itself up and waits for its parent +object to transit to a state that allows access to its children: + + (1) State FSCACHE_OBJECT_INIT. + + Initialise the object and wait for the parent object to become active. In + the cache, it is expected that it will not be possible to look an object + up from the parent object, until that parent object itself has been looked + up. + +There are initialisation states in which the object sets itself up and accesses +disk for the object metadata: + + (2) State FSCACHE_OBJECT_LOOKING_UP. + + Look up the object on disk, using the parent as a starting point. + FS-Cache expects the cache backend to probe the cache to see whether this + object is represented there, and if it is, to see if it's valid (coherency + management). + + The cache should call fscache_object_lookup_negative() to indicate lookup + failure for whatever reason, and should call fscache_obtained_object() to + indicate success. + + At the completion of lookup, FS-Cache will let the netfs go ahead with + read operations, no matter whether the file is yet cached. If not yet + cached, read operations will be immediately rejected with ENODATA until + the first known page is uncached - as to that point there can be no data + to be read out of the cache for that file that isn't currently also held + in the pagecache. + + (3) State FSCACHE_OBJECT_CREATING. + + Create an object on disk, using the parent as a starting point. This + happens if the lookup failed to find the object, or if the object's + coherency data indicated what's on disk is out of date. In this state, + FS-Cache expects the cache to create + + The cache should call fscache_obtained_object() if creation completes + successfully, fscache_object_lookup_negative() otherwise. + + At the completion of creation, FS-Cache will start processing write + operations the netfs has queued for an object. If creation failed, the + write ops will be transparently discarded, and nothing recorded in the + cache. + +There are some normal running states in which the object spends its time +servicing netfs requests: + + (4) State FSCACHE_OBJECT_AVAILABLE. + + A transient state in which pending operations are started, child objects + are permitted to advance from FSCACHE_OBJECT_INIT state, and temporary + lookup data is freed. + + (5) State FSCACHE_OBJECT_ACTIVE. + + The normal running state. In this state, requests the netfs makes will be + passed on to the cache. + + (6) State FSCACHE_OBJECT_UPDATING. + + The state machine comes here to update the object in the cache from the + netfs's records. This involves updating the auxiliary data that is used + to maintain coherency. + +And there are terminal states in which an object cleans itself up, deallocates +memory and potentially deletes stuff from disk: + + (7) State FSCACHE_OBJECT_LC_DYING. + + The object comes here if it is dying because of a lookup or creation + error. This would be due to a disk error or system error of some sort. + Temporary data is cleaned up, and the parent is released. + + (8) State FSCACHE_OBJECT_DYING. + + The object comes here if it is dying due to an error, because its parent + cookie has been relinquished by the netfs or because the cache is being + withdrawn. + + Any child objects waiting on this one are given CPU time so that they too + can destroy themselves. This object waits for all its children to go away + before advancing to the next state. + + (9) State FSCACHE_OBJECT_ABORT_INIT. + + The object comes to this state if it was waiting on its parent in + FSCACHE_OBJECT_INIT, but its parent died. The object will destroy itself + so that the parent may proceed from the FSCACHE_OBJECT_DYING state. + +(10) State FSCACHE_OBJECT_RELEASING. +(11) State FSCACHE_OBJECT_RECYCLING. + + The object comes to one of these two states when dying once it is rid of + all its children, if it is dying because the netfs relinquished its + cookie. In the first state, the cached data is expected to persist, and + in the second it will be deleted. + +(12) State FSCACHE_OBJECT_WITHDRAWING. + + The object transits to this state if the cache decides it wants to + withdraw the object from service, perhaps to make space, but also due to + error or just because the whole cache is being withdrawn. + +(13) State FSCACHE_OBJECT_DEAD. + + The object transits to this state when the in-memory object record is + ready to be deleted. The object processor shouldn't ever see an object in + this state. + + +THE SET OF EVENTS +----------------- + +There are a number of events that can be raised to an object state machine: + + (*) FSCACHE_OBJECT_EV_UPDATE + + The netfs requested that an object be updated. The state machine will ask + the cache backend to update the object, and the cache backend will ask the + netfs for details of the change through its cookie definition ops. + + (*) FSCACHE_OBJECT_EV_CLEARED + + This is signalled in two circumstances: + + (a) when an object's last child object is dropped and + + (b) when the last operation outstanding on an object is completed. + + This is used to proceed from the dying state. + + (*) FSCACHE_OBJECT_EV_ERROR + + This is signalled when an I/O error occurs during the processing of some + object. + + (*) FSCACHE_OBJECT_EV_RELEASE + (*) FSCACHE_OBJECT_EV_RETIRE + + These are signalled when the netfs relinquishes a cookie it was using. + The event selected depends on whether the netfs asks for the backing + object to be retired (deleted) or retained. + + (*) FSCACHE_OBJECT_EV_WITHDRAW + + This is signalled when the cache backend wants to withdraw an object. + This means that the object will have to be detached from the netfs's + cookie. + +Because the withdrawing releasing/retiring events are all handled by the object +state machine, it doesn't matter if there's a collision with both ends trying +to sever the connection at the same time. The state machine can just pick +which one it wants to honour, and that effects the other. diff --git a/fs/fscache/Makefile b/fs/fscache/Makefile index ecf6946eaeb..4420ac6ea10 100644 --- a/fs/fscache/Makefile +++ b/fs/fscache/Makefile @@ -7,7 +7,8 @@ fscache-y := \ cookie.o \ fsdef.o \ main.o \ - netfs.o + netfs.o \ + object.o fscache-$(CONFIG_PROC_FS) += proc.o fscache-$(CONFIG_FSCACHE_STATS) += stats.o diff --git a/fs/fscache/internal.h b/fs/fscache/internal.h index 16389942a54..529f4de328c 100644 --- a/fs/fscache/internal.h +++ b/fs/fscache/internal.h @@ -85,6 +85,18 @@ extern struct kobject *fscache_root; extern int fscache_wait_bit(void *); extern int fscache_wait_bit_interruptible(void *); +/* + * fsc-object.c + */ +extern void fscache_withdrawing_object(struct fscache_cache *, + struct fscache_object *); +extern void fscache_enqueue_object(struct fscache_object *); + +/* + * fsc-operation.c + */ +#define fscache_start_operations(obj) BUG() + /* * fsc-proc.c */ @@ -196,7 +208,19 @@ extern const struct file_operations fscache_stats_fops; static inline void fscache_raise_event(struct fscache_object *object, unsigned event) { - BUG(); // TODO + if (!test_and_set_bit(event, &object->events) && + test_bit(event, &object->event_mask)) + fscache_enqueue_object(object); +} + +/* + * drop a reference to a cookie + */ +static inline void fscache_cookie_put(struct fscache_cookie *cookie) +{ + BUG_ON(atomic_read(&cookie->usage) <= 0); + if (atomic_dec_and_test(&cookie->usage)) + __fscache_cookie_put(cookie); } /*****************************************************************************/ diff --git a/fs/fscache/object.c b/fs/fscache/object.c new file mode 100644 index 00000000000..392a41b1b79 --- /dev/null +++ b/fs/fscache/object.c @@ -0,0 +1,810 @@ +/* FS-Cache object state machine handler + * + * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + * See Documentation/filesystems/caching/object.txt for a description of the + * object state machine and the in-kernel representations. + */ + +#define FSCACHE_DEBUG_LEVEL COOKIE +#include +#include "internal.h" + +const char *fscache_object_states[] = { + [FSCACHE_OBJECT_INIT] = "OBJECT_INIT", + [FSCACHE_OBJECT_LOOKING_UP] = "OBJECT_LOOKING_UP", + [FSCACHE_OBJECT_CREATING] = "OBJECT_CREATING", + [FSCACHE_OBJECT_AVAILABLE] = "OBJECT_AVAILABLE", + [FSCACHE_OBJECT_ACTIVE] = "OBJECT_ACTIVE", + [FSCACHE_OBJECT_UPDATING] = "OBJECT_UPDATING", + [FSCACHE_OBJECT_DYING] = "OBJECT_DYING", + [FSCACHE_OBJECT_LC_DYING] = "OBJECT_LC_DYING", + [FSCACHE_OBJECT_ABORT_INIT] = "OBJECT_ABORT_INIT", + [FSCACHE_OBJECT_RELEASING] = "OBJECT_RELEASING", + [FSCACHE_OBJECT_RECYCLING] = "OBJECT_RECYCLING", + [FSCACHE_OBJECT_WITHDRAWING] = "OBJECT_WITHDRAWING", + [FSCACHE_OBJECT_DEAD] = "OBJECT_DEAD", +}; +EXPORT_SYMBOL(fscache_object_states); + +static void fscache_object_slow_work_put_ref(struct slow_work *); +static int fscache_object_slow_work_get_ref(struct slow_work *); +static void fscache_object_slow_work_execute(struct slow_work *); +static void fscache_initialise_object(struct fscache_object *); +static void fscache_lookup_object(struct fscache_object *); +static void fscache_object_available(struct fscache_object *); +static void fscache_release_object(struct fscache_object *); +static void fscache_withdraw_object(struct fscache_object *); +static void fscache_enqueue_dependents(struct fscache_object *); +static void fscache_dequeue_object(struct fscache_object *); + +const struct slow_work_ops fscache_object_slow_work_ops = { + .get_ref = fscache_object_slow_work_get_ref, + .put_ref = fscache_object_slow_work_put_ref, + .execute = fscache_object_slow_work_execute, +}; +EXPORT_SYMBOL(fscache_object_slow_work_ops); + +/* + * we need to notify the parent when an op completes that we had outstanding + * upon it + */ +static inline void fscache_done_parent_op(struct fscache_object *object) +{ + struct fscache_object *parent = object->parent; + + _enter("OBJ%x {OBJ%x,%x}", + object->debug_id, parent->debug_id, parent->n_ops); + + spin_lock_nested(&parent->lock, 1); + parent->n_ops--; + parent->n_obj_ops--; + if (parent->n_ops == 0) + fscache_raise_event(parent, FSCACHE_OBJECT_EV_CLEARED); + spin_unlock(&parent->lock); +} + +/* + * process events that have been sent to an object's state machine + * - initiates parent lookup + * - does object lookup + * - does object creation + * - does object recycling and retirement + * - does object withdrawal + */ +static void fscache_object_state_machine(struct fscache_object *object) +{ + enum fscache_object_state new_state; + + ASSERT(object != NULL); + + _enter("{OBJ%x,%s,%lx}", + object->debug_id, fscache_object_states[object->state], + object->events); + + switch (object->state) { + /* wait for the parent object to become ready */ + case FSCACHE_OBJECT_INIT: + object->event_mask = + ULONG_MAX & ~(1 << FSCACHE_OBJECT_EV_CLEARED); + fscache_initialise_object(object); + goto done; + + /* look up the object metadata on disk */ + case FSCACHE_OBJECT_LOOKING_UP: + fscache_lookup_object(object); + goto lookup_transit; + + /* create the object metadata on disk */ + case FSCACHE_OBJECT_CREATING: + fscache_lookup_object(object); + goto lookup_transit; + + /* handle an object becoming available; start pending + * operations and queue dependent operations for processing */ + case FSCACHE_OBJECT_AVAILABLE: + fscache_object_available(object); + goto active_transit; + + /* normal running state */ + case FSCACHE_OBJECT_ACTIVE: + goto active_transit; + + /* update the object metadata on disk */ + case FSCACHE_OBJECT_UPDATING: + clear_bit(FSCACHE_OBJECT_EV_UPDATE, &object->events); + fscache_stat(&fscache_n_updates_run); + object->cache->ops->update_object(object); + goto active_transit; + + /* handle an object dying during lookup or creation */ + case FSCACHE_OBJECT_LC_DYING: + object->event_mask &= ~(1 << FSCACHE_OBJECT_EV_UPDATE); + object->cache->ops->lookup_complete(object); + + spin_lock(&object->lock); + object->state = FSCACHE_OBJECT_DYING; + if (test_and_clear_bit(FSCACHE_COOKIE_CREATING, + &object->cookie->flags)) + wake_up_bit(&object->cookie->flags, + FSCACHE_COOKIE_CREATING); + spin_unlock(&object->lock); + + fscache_done_parent_op(object); + + /* wait for completion of all active operations on this object + * and the death of all child objects of this object */ + case FSCACHE_OBJECT_DYING: + dying: + clear_bit(FSCACHE_OBJECT_EV_CLEARED, &object->events); + spin_lock(&object->lock); + _debug("dying OBJ%x {%d,%d}", + object->debug_id, object->n_ops, object->n_children); + if (object->n_ops == 0 && object->n_children == 0) { + object->event_mask &= + ~(1 << FSCACHE_OBJECT_EV_CLEARED); + object->event_mask |= + (1 << FSCACHE_OBJECT_EV_WITHDRAW) | + (1 << FSCACHE_OBJECT_EV_RETIRE) | + (1 << FSCACHE_OBJECT_EV_RELEASE) | + (1 << FSCACHE_OBJECT_EV_ERROR); + } else { + object->event_mask &= + ~((1 << FSCACHE_OBJECT_EV_WITHDRAW) | + (1 << FSCACHE_OBJECT_EV_RETIRE) | + (1 << FSCACHE_OBJECT_EV_RELEASE) | + (1 << FSCACHE_OBJECT_EV_ERROR)); + object->event_mask |= + 1 << FSCACHE_OBJECT_EV_CLEARED; + } + spin_unlock(&object->lock); + fscache_enqueue_dependents(object); + goto terminal_transit; + + /* handle an abort during initialisation */ + case FSCACHE_OBJECT_ABORT_INIT: + _debug("handle abort init %lx", object->events); + object->event_mask &= ~(1 << FSCACHE_OBJECT_EV_UPDATE); + + spin_lock(&object->lock); + fscache_dequeue_object(object); + + object->state = FSCACHE_OBJECT_DYING; + if (test_and_clear_bit(FSCACHE_COOKIE_CREATING, + &object->cookie->flags)) + wake_up_bit(&object->cookie->flags, + FSCACHE_COOKIE_CREATING); + spin_unlock(&object->lock); + goto dying; + + /* handle the netfs releasing an object and possibly marking it + * obsolete too */ + case FSCACHE_OBJECT_RELEASING: + case FSCACHE_OBJECT_RECYCLING: + object->event_mask &= + ~((1 << FSCACHE_OBJECT_EV_WITHDRAW) | + (1 << FSCACHE_OBJECT_EV_RETIRE) | + (1 << FSCACHE_OBJECT_EV_RELEASE) | + (1 << FSCACHE_OBJECT_EV_ERROR)); + fscache_release_object(object); + spin_lock(&object->lock); + object->state = FSCACHE_OBJECT_DEAD; + spin_unlock(&object->lock); + fscache_stat(&fscache_n_object_dead); + goto terminal_transit; + + /* handle the parent cache of this object being withdrawn from + * active service */ + case FSCACHE_OBJECT_WITHDRAWING: + object->event_mask &= + ~((1 << FSCACHE_OBJECT_EV_WITHDRAW) | + (1 << FSCACHE_OBJECT_EV_RETIRE) | + (1 << FSCACHE_OBJECT_EV_RELEASE) | + (1 << FSCACHE_OBJECT_EV_ERROR)); + fscache_withdraw_object(object); + spin_lock(&object->lock); + object->state = FSCACHE_OBJECT_DEAD; + spin_unlock(&object->lock); + fscache_stat(&fscache_n_object_dead); + goto terminal_transit; + + /* complain about the object being woken up once it is + * deceased */ + case FSCACHE_OBJECT_DEAD: + printk(KERN_ERR "FS-Cache:" + " Unexpected event in dead state %lx\n", + object->events & object->event_mask); + BUG(); + + default: + printk(KERN_ERR "FS-Cache: Unknown object state %u\n", + object->state); + BUG(); + } + + /* determine the transition from a lookup state */ +lookup_transit: + switch (fls(object->events & object->event_mask) - 1) { + case FSCACHE_OBJECT_EV_WITHDRAW: + case FSCACHE_OBJECT_EV_RETIRE: + case FSCACHE_OBJECT_EV_RELEASE: + case FSCACHE_OBJECT_EV_ERROR: + new_state = FSCACHE_OBJECT_LC_DYING; + goto change_state; + case FSCACHE_OBJECT_EV_REQUEUE: + goto done; + case -1: + goto done; /* sleep until event */ + default: + goto unsupported_event; + } + + /* determine the transition from an active state */ +active_transit: + switch (fls(object->events & object->event_mask) - 1) { + case FSCACHE_OBJECT_EV_WITHDRAW: + case FSCACHE_OBJECT_EV_RETIRE: + case FSCACHE_OBJECT_EV_RELEASE: + case FSCACHE_OBJECT_EV_ERROR: + new_state = FSCACHE_OBJECT_DYING; + goto change_state; + case FSCACHE_OBJECT_EV_UPDATE: + new_state = FSCACHE_OBJECT_UPDATING; + goto change_state; + case -1: + new_state = FSCACHE_OBJECT_ACTIVE; + goto change_state; /* sleep until event */ + default: + goto unsupported_event; + } + + /* determine the transition from a terminal state */ +terminal_transit: + switch (fls(object->events & object->event_mask) - 1) { + case FSCACHE_OBJECT_EV_WITHDRAW: + new_state = FSCACHE_OBJECT_WITHDRAWING; + goto change_state; + case FSCACHE_OBJECT_EV_RETIRE: + new_state = FSCACHE_OBJECT_RECYCLING; + goto change_state; + case FSCACHE_OBJECT_EV_RELEASE: + new_state = FSCACHE_OBJECT_RELEASING; + goto change_state; + case FSCACHE_OBJECT_EV_ERROR: + new_state = FSCACHE_OBJECT_WITHDRAWING; + goto change_state; + case FSCACHE_OBJECT_EV_CLEARED: + new_state = FSCACHE_OBJECT_DYING; + goto change_state; + case -1: + goto done; /* sleep until event */ + default: + goto unsupported_event; + } + +change_state: + spin_lock(&object->lock); + object->state = new_state; + spin_unlock(&object->lock); + +done: + _leave(" [->%s]", fscache_object_states[object->state]); + return; + +unsupported_event: + printk(KERN_ERR "FS-Cache:" + " Unsupported event %lx [mask %lx] in state %s\n", + object->events, object->event_mask, + fscache_object_states[object->state]); + BUG(); +} + +/* + * execute an object + */ +static void fscache_object_slow_work_execute(struct slow_work *work) +{ + struct fscache_object *object = + container_of(work, struct fscache_object, work); + unsigned long start; + + _enter("{OBJ%x}", object->debug_id); + + clear_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events); + + start = jiffies; + fscache_object_state_machine(object); + fscache_hist(fscache_objs_histogram, start); + if (object->events & object->event_mask) + fscache_enqueue_object(object); +} + +/* + * initialise an object + * - check the specified object's parent to see if we can make use of it + * immediately to do a creation + * - we may need to start the process of creating a parent and we need to wait + * for the parent's lookup and creation to complete if it's not there yet + * - an object's cookie is pinned until we clear FSCACHE_COOKIE_CREATING on the + * leaf-most cookies of the object and all its children + */ +static void fscache_initialise_object(struct fscache_object *object) +{ + struct fscache_object *parent; + + _enter(""); + ASSERT(object->cookie != NULL); + ASSERT(object->cookie->parent != NULL); + ASSERT(list_empty(&object->work.link)); + + if (object->events & ((1 << FSCACHE_OBJECT_EV_ERROR) | + (1 << FSCACHE_OBJECT_EV_RELEASE) | + (1 << FSCACHE_OBJECT_EV_RETIRE) | + (1 << FSCACHE_OBJECT_EV_WITHDRAW))) { + _debug("abort init %lx", object->events); + spin_lock(&object->lock); + object->state = FSCACHE_OBJECT_ABORT_INIT; + spin_unlock(&object->lock); + return; + } + + spin_lock(&object->cookie->lock); + spin_lock_nested(&object->cookie->parent->lock, 1); + + parent = object->parent; + if (!parent) { + _debug("no parent"); + set_bit(FSCACHE_OBJECT_EV_WITHDRAW, &object->events); + } else { + spin_lock(&object->lock); + spin_lock_nested(&parent->lock, 1); + _debug("parent %s", fscache_object_states[parent->state]); + + if (parent->state >= FSCACHE_OBJECT_DYING) { + _debug("bad parent"); + set_bit(FSCACHE_OBJECT_EV_WITHDRAW, &object->events); + } else if (parent->state < FSCACHE_OBJECT_AVAILABLE) { + _debug("wait"); + + /* we may get woken up in this state by child objects + * binding on to us, so we need to make sure we don't + * add ourself to the list multiple times */ + if (list_empty(&object->dep_link)) { + object->cache->ops->grab_object(object); + list_add(&object->dep_link, + &parent->dependents); + + /* fscache_acquire_non_index_cookie() uses this + * to wake the chain up */ + if (parent->state == FSCACHE_OBJECT_INIT) + fscache_enqueue_object(parent); + } + } else { + _debug("go"); + parent->n_ops++; + parent->n_obj_ops++; + object->lookup_jif = jiffies; + object->state = FSCACHE_OBJECT_LOOKING_UP; + set_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events); + } + + spin_unlock(&parent->lock); + spin_unlock(&object->lock); + } + + spin_unlock(&object->cookie->parent->lock); + spin_unlock(&object->cookie->lock); + _leave(""); +} + +/* + * look an object up in the cache from which it was allocated + * - we hold an "access lock" on the parent object, so the parent object cannot + * be withdrawn by either party till we've finished + * - an object's cookie is pinned until we clear FSCACHE_COOKIE_CREATING on the + * leaf-most cookies of the object and all its children + */ +static void fscache_lookup_object(struct fscache_object *object) +{ + struct fscache_cookie *cookie = object->cookie; + struct fscache_object *parent; + + _enter(""); + + parent = object->parent; + ASSERT(parent != NULL); + ASSERTCMP(parent->n_ops, >, 0); + ASSERTCMP(parent->n_obj_ops, >, 0); + + /* make sure the parent is still available */ + ASSERTCMP(parent->state, >=, FSCACHE_OBJECT_AVAILABLE); + + if (parent->state >= FSCACHE_OBJECT_DYING || + test_bit(FSCACHE_IOERROR, &object->cache->flags)) { + _debug("unavailable"); + set_bit(FSCACHE_OBJECT_EV_WITHDRAW, &object->events); + _leave(""); + return; + } + + _debug("LOOKUP \"%s/%s\" in \"%s\"", + parent->cookie->def->name, cookie->def->name, + object->cache->tag->name); + + fscache_stat(&fscache_n_object_lookups); + object->cache->ops->lookup_object(object); + + if (test_bit(FSCACHE_OBJECT_EV_ERROR, &object->events)) + set_bit(FSCACHE_COOKIE_UNAVAILABLE, &cookie->flags); + + _leave(""); +} + +/** + * fscache_object_lookup_negative - Note negative cookie lookup + * @object: Object pointing to cookie to mark + * + * Note negative lookup, permitting those waiting to read data from an already + * existing backing object to continue as there's no data for them to read. + */ +void fscache_object_lookup_negative(struct fscache_object *object) +{ + struct fscache_cookie *cookie = object->cookie; + + _enter("{OBJ%x,%s}", + object->debug_id, fscache_object_states[object->state]); + + spin_lock(&object->lock); + if (object->state == FSCACHE_OBJECT_LOOKING_UP) { + fscache_stat(&fscache_n_object_lookups_negative); + + /* transit here to allow write requests to begin stacking up + * and read requests to begin returning ENODATA */ + object->state = FSCACHE_OBJECT_CREATING; + spin_unlock(&object->lock); + + set_bit(FSCACHE_COOKIE_PENDING_FILL, &cookie->flags); + set_bit(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags); + + _debug("wake up lookup %p", &cookie->flags); + smp_mb__before_clear_bit(); + clear_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags); + smp_mb__after_clear_bit(); + wake_up_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP); + set_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events); + } else { + ASSERTCMP(object->state, ==, FSCACHE_OBJECT_CREATING); + spin_unlock(&object->lock); + } + + _leave(""); +} +EXPORT_SYMBOL(fscache_object_lookup_negative); + +/** + * fscache_obtained_object - Note successful object lookup or creation + * @object: Object pointing to cookie to mark + * + * Note successful lookup and/or creation, permitting those waiting to write + * data to a backing object to continue. + * + * Note that after calling this, an object's cookie may be relinquished by the + * netfs, and so must be accessed with object lock held. + */ +void fscache_obtained_object(struct fscache_object *object) +{ + struct fscache_cookie *cookie = object->cookie; + + _enter("{OBJ%x,%s}", + object->debug_id, fscache_object_states[object->state]); + + /* if we were still looking up, then we must have a positive lookup + * result, in which case there may be data available */ + spin_lock(&object->lock); + if (object->state == FSCACHE_OBJECT_LOOKING_UP) { + fscache_stat(&fscache_n_object_lookups_positive); + + clear_bit(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags); + + object->state = FSCACHE_OBJECT_AVAILABLE; + spin_unlock(&object->lock); + + smp_mb__before_clear_bit(); + clear_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags); + smp_mb__after_clear_bit(); + wake_up_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP); + set_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events); + } else { + ASSERTCMP(object->state, ==, FSCACHE_OBJECT_CREATING); + fscache_stat(&fscache_n_object_created); + + object->state = FSCACHE_OBJECT_AVAILABLE; + spin_unlock(&object->lock); + set_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events); + smp_wmb(); + } + + if (test_and_clear_bit(FSCACHE_COOKIE_CREATING, &cookie->flags)) + wake_up_bit(&cookie->flags, FSCACHE_COOKIE_CREATING); + + _leave(""); +} +EXPORT_SYMBOL(fscache_obtained_object); + +/* + * handle an object that has just become available + */ +static void fscache_object_available(struct fscache_object *object) +{ + _enter("{OBJ%x}", object->debug_id); + + spin_lock(&object->lock); + + if (test_and_clear_bit(FSCACHE_COOKIE_CREATING, &object->cookie->flags)) + wake_up_bit(&object->cookie->flags, FSCACHE_COOKIE_CREATING); + + fscache_done_parent_op(object); + if (object->n_in_progress == 0) { + if (object->n_ops > 0) { + ASSERTCMP(object->n_ops, >=, object->n_obj_ops); + ASSERTIF(object->n_ops > object->n_obj_ops, + !list_empty(&object->pending_ops)); + fscache_start_operations(object); + } else { + ASSERT(list_empty(&object->pending_ops)); + } + } + spin_unlock(&object->lock); + + object->cache->ops->lookup_complete(object); + fscache_enqueue_dependents(object); + + fscache_hist(fscache_obj_instantiate_histogram, object->lookup_jif); + fscache_stat(&fscache_n_object_avail); + + _leave(""); +} + +/* + * drop an object's attachments + */ +static void fscache_drop_object(struct fscache_object *object) +{ + struct fscache_object *parent = object->parent; + struct fscache_cache *cache = object->cache; + + _enter("{OBJ%x,%d}", object->debug_id, object->n_children); + + spin_lock(&cache->object_list_lock); + list_del_init(&object->cache_link); + spin_unlock(&cache->object_list_lock); + + cache->ops->drop_object(object); + + if (parent) { + _debug("release parent OBJ%x {%d}", + parent->debug_id, parent->n_children); + + spin_lock(&parent->lock); + parent->n_children--; + if (parent->n_children == 0) + fscache_raise_event(parent, FSCACHE_OBJECT_EV_CLEARED); + spin_unlock(&parent->lock); + object->parent = NULL; + } + + /* this just shifts the object release to the slow work processor */ + object->cache->ops->put_object(object); + + _leave(""); +} + +/* + * release or recycle an object that the netfs has discarded + */ +static void fscache_release_object(struct fscache_object *object) +{ + _enter(""); + + fscache_drop_object(object); +} + +/* + * withdraw an object from active service + */ +static void fscache_withdraw_object(struct fscache_object *object) +{ + struct fscache_cookie *cookie; + bool detached; + + _enter(""); + + spin_lock(&object->lock); + cookie = object->cookie; + if (cookie) { + /* need to get the cookie lock before the object lock, starting + * from the object pointer */ + atomic_inc(&cookie->usage); + spin_unlock(&object->lock); + + detached = false; + spin_lock(&cookie->lock); + spin_lock(&object->lock); + + if (object->cookie == cookie) { + hlist_del_init(&object->cookie_link); + object->cookie = NULL; + detached = true; + } + spin_unlock(&cookie->lock); + fscache_cookie_put(cookie); + if (detached) + fscache_cookie_put(cookie); + } + + spin_unlock(&object->lock); + + fscache_drop_object(object); +} + +/* + * withdraw an object from active service at the behest of the cache + * - need break the links to a cached object cookie + * - called under two situations: + * (1) recycler decides to reclaim an in-use object + * (2) a cache is unmounted + * - have to take care as the cookie can be being relinquished by the netfs + * simultaneously + * - the object is pinned by the caller holding a refcount on it + */ +void fscache_withdrawing_object(struct fscache_cache *cache, + struct fscache_object *object) +{ + bool enqueue = false; + + _enter(",OBJ%x", object->debug_id); + + spin_lock(&object->lock); + if (object->state < FSCACHE_OBJECT_WITHDRAWING) { + object->state = FSCACHE_OBJECT_WITHDRAWING; + enqueue = true; + } + spin_unlock(&object->lock); + + if (enqueue) + fscache_enqueue_object(object); + + _leave(""); +} + +/* + * allow the slow work item processor to get a ref on an object + */ +static int fscache_object_slow_work_get_ref(struct slow_work *work) +{ + struct fscache_object *object = + container_of(work, struct fscache_object, work); + + return object->cache->ops->grab_object(object) ? 0 : -EAGAIN; +} + +/* + * allow the slow work item processor to discard a ref on a work item + */ +static void fscache_object_slow_work_put_ref(struct slow_work *work) +{ + struct fscache_object *object = + container_of(work, struct fscache_object, work); + + return object->cache->ops->put_object(object); +} + +/* + * enqueue an object for metadata-type processing + */ +void fscache_enqueue_object(struct fscache_object *object) +{ + _enter("{OBJ%x}", object->debug_id); + + slow_work_enqueue(&object->work); +} + +/* + * enqueue the dependents of an object for metadata-type processing + * - the caller must hold the object's lock + * - this may cause an already locked object to wind up being processed again + */ +static void fscache_enqueue_dependents(struct fscache_object *object) +{ + struct fscache_object *dep; + + _enter("{OBJ%x}", object->debug_id); + + if (list_empty(&object->dependents)) + return; + + spin_lock(&object->lock); + + while (!list_empty(&object->dependents)) { + dep = list_entry(object->dependents.next, + struct fscache_object, dep_link); + list_del_init(&dep->dep_link); + + + /* sort onto appropriate lists */ + fscache_enqueue_object(dep); + dep->cache->ops->put_object(dep); + + if (!list_empty(&object->dependents)) + cond_resched_lock(&object->lock); + } + + spin_unlock(&object->lock); +} + +/* + * remove an object from whatever queue it's waiting on + * - the caller must hold object->lock + */ +void fscache_dequeue_object(struct fscache_object *object) +{ + _enter("{OBJ%x}", object->debug_id); + + if (!list_empty(&object->dep_link)) { + spin_lock(&object->parent->lock); + list_del_init(&object->dep_link); + spin_unlock(&object->parent->lock); + } + + _leave(""); +} + +/** + * fscache_check_aux - Ask the netfs whether an object on disk is still valid + * @object: The object to ask about + * @data: The auxiliary data for the object + * @datalen: The size of the auxiliary data + * + * This function consults the netfs about the coherency state of an object + */ +enum fscache_checkaux fscache_check_aux(struct fscache_object *object, + const void *data, uint16_t datalen) +{ + enum fscache_checkaux result; + + if (!object->cookie->def->check_aux) { + fscache_stat(&fscache_n_checkaux_none); + return FSCACHE_CHECKAUX_OKAY; + } + + result = object->cookie->def->check_aux(object->cookie->netfs_data, + data, datalen); + switch (result) { + /* entry okay as is */ + case FSCACHE_CHECKAUX_OKAY: + fscache_stat(&fscache_n_checkaux_okay); + break; + + /* entry requires update */ + case FSCACHE_CHECKAUX_NEEDS_UPDATE: + fscache_stat(&fscache_n_checkaux_update); + break; + + /* entry requires deletion */ + case FSCACHE_CHECKAUX_OBSOLETE: + fscache_stat(&fscache_n_checkaux_obsolete); + break; + + default: + BUG(); + } + + return result; +} +EXPORT_SYMBOL(fscache_check_aux); -- cgit v1.2.3-70-g09d2 From ccc4fc3d11e91477036d1f82bfa2d442f6ce77f0 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:38 +0100 Subject: FS-Cache: Implement the cookie management part of the netfs API Implement the cookie management part of the FS-Cache netfs client API. The documentation and API header file were added in a previous patch. This patch implements the following three functions: (1) fscache_acquire_cookie(). Acquire a cookie to represent an object to the netfs. If the object in question is a non-index object, then that object and its parent indices will be created on disk at this point if they don't already exist. Index creation is deferred because an index may reside in multiple caches. (2) fscache_relinquish_cookie(). Retire or release a cookie previously acquired. At this point, the object on disk may be destroyed. (3) fscache_update_cookie(). Update the in-cache representation of a cookie. This is used to update the auxiliary data for coherency management purposes. With this patch it is possible to have a netfs instruct a cache backend to look up, validate and create metadata on disk and to destroy it again. The ability to actually store and retrieve data in the objects so created is added in later patches. Note that these functions will never return an error. _All_ errors are handled internally to FS-Cache. The worst that can happen is that fscache_acquire_cookie() may return a NULL pointer - which is considered a negative cookie pointer and can be passed back to any function that takes a cookie without harm. A negative cookie pointer merely suppresses caching at that level. The stub in linux/fscache.h will detect inline the negative cookie pointer and abort the operation as fast as possible. This means that the compiler doesn't have to set up for a call in that case. See the documentation in Documentation/filesystems/caching/netfs-api.txt for more information. Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Al Viro Tested-by: Daire Byrne --- fs/fscache/cookie.c | 444 ++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/fscache.h | 16 +- 2 files changed, 459 insertions(+), 1 deletion(-) (limited to 'fs') diff --git a/fs/fscache/cookie.c b/fs/fscache/cookie.c index 47fd75b832e..72fd18f6c71 100644 --- a/fs/fscache/cookie.c +++ b/fs/fscache/cookie.c @@ -7,6 +7,9 @@ * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. + * + * See Documentation/filesystems/caching/netfs-api.txt for more information on + * the netfs API. */ #define FSCACHE_DEBUG_LEVEL COOKIE @@ -16,6 +19,14 @@ struct kmem_cache *fscache_cookie_jar; +static atomic_t fscache_object_debug_id = ATOMIC_INIT(0); + +static int fscache_acquire_non_index_cookie(struct fscache_cookie *cookie); +static int fscache_alloc_object(struct fscache_cache *cache, + struct fscache_cookie *cookie); +static int fscache_attach_object(struct fscache_cookie *cookie, + struct fscache_object *object); + /* * initialise an cookie jar slab element prior to any use */ @@ -28,6 +39,439 @@ void fscache_cookie_init_once(void *_cookie) INIT_HLIST_HEAD(&cookie->backing_objects); } +/* + * request a cookie to represent an object (index, datafile, xattr, etc) + * - parent specifies the parent object + * - the top level index cookie for each netfs is stored in the fscache_netfs + * struct upon registration + * - def points to the definition + * - the netfs_data will be passed to the functions pointed to in *def + * - all attached caches will be searched to see if they contain this object + * - index objects aren't stored on disk until there's a dependent file that + * needs storing + * - other objects are stored in a selected cache immediately, and all the + * indices forming the path to it are instantiated if necessary + * - we never let on to the netfs about errors + * - we may set a negative cookie pointer, but that's okay + */ +struct fscache_cookie *__fscache_acquire_cookie( + struct fscache_cookie *parent, + const struct fscache_cookie_def *def, + void *netfs_data) +{ + struct fscache_cookie *cookie; + + BUG_ON(!def); + + _enter("{%s},{%s},%p", + parent ? (char *) parent->def->name : "", + def->name, netfs_data); + + fscache_stat(&fscache_n_acquires); + + /* if there's no parent cookie, then we don't create one here either */ + if (!parent) { + fscache_stat(&fscache_n_acquires_null); + _leave(" [no parent]"); + return NULL; + } + + /* validate the definition */ + BUG_ON(!def->get_key); + BUG_ON(!def->name[0]); + + BUG_ON(def->type == FSCACHE_COOKIE_TYPE_INDEX && + parent->def->type != FSCACHE_COOKIE_TYPE_INDEX); + + /* allocate and initialise a cookie */ + cookie = kmem_cache_alloc(fscache_cookie_jar, GFP_KERNEL); + if (!cookie) { + fscache_stat(&fscache_n_acquires_oom); + _leave(" [ENOMEM]"); + return NULL; + } + + atomic_set(&cookie->usage, 1); + atomic_set(&cookie->n_children, 0); + + atomic_inc(&parent->usage); + atomic_inc(&parent->n_children); + + cookie->def = def; + cookie->parent = parent; + cookie->netfs_data = netfs_data; + cookie->flags = 0; + + INIT_RADIX_TREE(&cookie->stores, GFP_NOFS); + + switch (cookie->def->type) { + case FSCACHE_COOKIE_TYPE_INDEX: + fscache_stat(&fscache_n_cookie_index); + break; + case FSCACHE_COOKIE_TYPE_DATAFILE: + fscache_stat(&fscache_n_cookie_data); + break; + default: + fscache_stat(&fscache_n_cookie_special); + break; + } + + /* if the object is an index then we need do nothing more here - we + * create indices on disk when we need them as an index may exist in + * multiple caches */ + if (cookie->def->type != FSCACHE_COOKIE_TYPE_INDEX) { + if (fscache_acquire_non_index_cookie(cookie) < 0) { + atomic_dec(&parent->n_children); + __fscache_cookie_put(cookie); + fscache_stat(&fscache_n_acquires_nobufs); + _leave(" = NULL"); + return NULL; + } + } + + fscache_stat(&fscache_n_acquires_ok); + _leave(" = %p", cookie); + return cookie; +} +EXPORT_SYMBOL(__fscache_acquire_cookie); + +/* + * acquire a non-index cookie + * - this must make sure the index chain is instantiated and instantiate the + * object representation too + */ +static int fscache_acquire_non_index_cookie(struct fscache_cookie *cookie) +{ + struct fscache_object *object; + struct fscache_cache *cache; + uint64_t i_size; + int ret; + + _enter(""); + + cookie->flags = 1 << FSCACHE_COOKIE_UNAVAILABLE; + + /* now we need to see whether the backing objects for this cookie yet + * exist, if not there'll be nothing to search */ + down_read(&fscache_addremove_sem); + + if (list_empty(&fscache_cache_list)) { + up_read(&fscache_addremove_sem); + _leave(" = 0 [no caches]"); + return 0; + } + + /* select a cache in which to store the object */ + cache = fscache_select_cache_for_object(cookie->parent); + if (!cache) { + up_read(&fscache_addremove_sem); + fscache_stat(&fscache_n_acquires_no_cache); + _leave(" = -ENOMEDIUM [no cache]"); + return -ENOMEDIUM; + } + + _debug("cache %s", cache->tag->name); + + cookie->flags = + (1 << FSCACHE_COOKIE_LOOKING_UP) | + (1 << FSCACHE_COOKIE_CREATING) | + (1 << FSCACHE_COOKIE_NO_DATA_YET); + + /* ask the cache to allocate objects for this cookie and its parent + * chain */ + ret = fscache_alloc_object(cache, cookie); + if (ret < 0) { + up_read(&fscache_addremove_sem); + _leave(" = %d", ret); + return ret; + } + + /* pass on how big the object we're caching is supposed to be */ + cookie->def->get_attr(cookie->netfs_data, &i_size); + + spin_lock(&cookie->lock); + if (hlist_empty(&cookie->backing_objects)) { + spin_unlock(&cookie->lock); + goto unavailable; + } + + object = hlist_entry(cookie->backing_objects.first, + struct fscache_object, cookie_link); + + fscache_set_store_limit(object, i_size); + + /* initiate the process of looking up all the objects in the chain + * (done by fscache_initialise_object()) */ + fscache_enqueue_object(object); + + spin_unlock(&cookie->lock); + + /* we may be required to wait for lookup to complete at this point */ + if (!fscache_defer_lookup) { + _debug("non-deferred lookup %p", &cookie->flags); + wait_on_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP, + fscache_wait_bit, TASK_UNINTERRUPTIBLE); + _debug("complete"); + if (test_bit(FSCACHE_COOKIE_UNAVAILABLE, &cookie->flags)) + goto unavailable; + } + + up_read(&fscache_addremove_sem); + _leave(" = 0 [deferred]"); + return 0; + +unavailable: + up_read(&fscache_addremove_sem); + _leave(" = -ENOBUFS"); + return -ENOBUFS; +} + +/* + * recursively allocate cache object records for a cookie/cache combination + * - caller must be holding the addremove sem + */ +static int fscache_alloc_object(struct fscache_cache *cache, + struct fscache_cookie *cookie) +{ + struct fscache_object *object; + struct hlist_node *_n; + int ret; + + _enter("%p,%p{%s}", cache, cookie, cookie->def->name); + + spin_lock(&cookie->lock); + hlist_for_each_entry(object, _n, &cookie->backing_objects, + cookie_link) { + if (object->cache == cache) + goto object_already_extant; + } + spin_unlock(&cookie->lock); + + /* ask the cache to allocate an object (we may end up with duplicate + * objects at this stage, but we sort that out later) */ + object = cache->ops->alloc_object(cache, cookie); + if (IS_ERR(object)) { + fscache_stat(&fscache_n_object_no_alloc); + ret = PTR_ERR(object); + goto error; + } + + fscache_stat(&fscache_n_object_alloc); + + object->debug_id = atomic_inc_return(&fscache_object_debug_id); + + _debug("ALLOC OBJ%x: %s {%lx}", + object->debug_id, cookie->def->name, object->events); + + ret = fscache_alloc_object(cache, cookie->parent); + if (ret < 0) + goto error_put; + + /* only attach if we managed to allocate all we needed, otherwise + * discard the object we just allocated and instead use the one + * attached to the cookie */ + if (fscache_attach_object(cookie, object) < 0) + cache->ops->put_object(object); + + _leave(" = 0"); + return 0; + +object_already_extant: + ret = -ENOBUFS; + if (object->state >= FSCACHE_OBJECT_DYING) { + spin_unlock(&cookie->lock); + goto error; + } + spin_unlock(&cookie->lock); + _leave(" = 0 [found]"); + return 0; + +error_put: + cache->ops->put_object(object); +error: + _leave(" = %d", ret); + return ret; +} + +/* + * attach a cache object to a cookie + */ +static int fscache_attach_object(struct fscache_cookie *cookie, + struct fscache_object *object) +{ + struct fscache_object *p; + struct fscache_cache *cache = object->cache; + struct hlist_node *_n; + int ret; + + _enter("{%s},{OBJ%x}", cookie->def->name, object->debug_id); + + spin_lock(&cookie->lock); + + /* there may be multiple initial creations of this object, but we only + * want one */ + ret = -EEXIST; + hlist_for_each_entry(p, _n, &cookie->backing_objects, cookie_link) { + if (p->cache == object->cache) { + if (p->state >= FSCACHE_OBJECT_DYING) + ret = -ENOBUFS; + goto cant_attach_object; + } + } + + /* pin the parent object */ + spin_lock_nested(&cookie->parent->lock, 1); + hlist_for_each_entry(p, _n, &cookie->parent->backing_objects, + cookie_link) { + if (p->cache == object->cache) { + if (p->state >= FSCACHE_OBJECT_DYING) { + ret = -ENOBUFS; + spin_unlock(&cookie->parent->lock); + goto cant_attach_object; + } + object->parent = p; + spin_lock(&p->lock); + p->n_children++; + spin_unlock(&p->lock); + break; + } + } + spin_unlock(&cookie->parent->lock); + + /* attach to the cache's object list */ + if (list_empty(&object->cache_link)) { + spin_lock(&cache->object_list_lock); + list_add(&object->cache_link, &cache->object_list); + spin_unlock(&cache->object_list_lock); + } + + /* attach to the cookie */ + object->cookie = cookie; + atomic_inc(&cookie->usage); + hlist_add_head(&object->cookie_link, &cookie->backing_objects); + ret = 0; + +cant_attach_object: + spin_unlock(&cookie->lock); + _leave(" = %d", ret); + return ret; +} + +/* + * update the index entries backing a cookie + */ +void __fscache_update_cookie(struct fscache_cookie *cookie) +{ + struct fscache_object *object; + struct hlist_node *_p; + + fscache_stat(&fscache_n_updates); + + if (!cookie) { + fscache_stat(&fscache_n_updates_null); + _leave(" [no cookie]"); + return; + } + + _enter("{%s}", cookie->def->name); + + BUG_ON(!cookie->def->get_aux); + + spin_lock(&cookie->lock); + + /* update the index entry on disk in each cache backing this cookie */ + hlist_for_each_entry(object, _p, + &cookie->backing_objects, cookie_link) { + fscache_raise_event(object, FSCACHE_OBJECT_EV_UPDATE); + } + + spin_unlock(&cookie->lock); + _leave(""); +} +EXPORT_SYMBOL(__fscache_update_cookie); + +/* + * release a cookie back to the cache + * - the object will be marked as recyclable on disk if retire is true + * - all dependents of this cookie must have already been unregistered + * (indices/files/pages) + */ +void __fscache_relinquish_cookie(struct fscache_cookie *cookie, int retire) +{ + struct fscache_cache *cache; + struct fscache_object *object; + unsigned long event; + + fscache_stat(&fscache_n_relinquishes); + + if (!cookie) { + fscache_stat(&fscache_n_relinquishes_null); + _leave(" [no cookie]"); + return; + } + + _enter("%p{%s,%p},%d", + cookie, cookie->def->name, cookie->netfs_data, retire); + + if (atomic_read(&cookie->n_children) != 0) { + printk(KERN_ERR "FS-Cache: Cookie '%s' still has children\n", + cookie->def->name); + BUG(); + } + + /* wait for the cookie to finish being instantiated (or to fail) */ + if (test_bit(FSCACHE_COOKIE_CREATING, &cookie->flags)) { + fscache_stat(&fscache_n_relinquishes_waitcrt); + wait_on_bit(&cookie->flags, FSCACHE_COOKIE_CREATING, + fscache_wait_bit, TASK_UNINTERRUPTIBLE); + } + + event = retire ? FSCACHE_OBJECT_EV_RETIRE : FSCACHE_OBJECT_EV_RELEASE; + + /* detach pointers back to the netfs */ + spin_lock(&cookie->lock); + + cookie->netfs_data = NULL; + cookie->def = NULL; + + /* break links with all the active objects */ + while (!hlist_empty(&cookie->backing_objects)) { + object = hlist_entry(cookie->backing_objects.first, + struct fscache_object, + cookie_link); + + _debug("RELEASE OBJ%x", object->debug_id); + + /* detach each cache object from the object cookie */ + spin_lock(&object->lock); + hlist_del_init(&object->cookie_link); + + cache = object->cache; + object->cookie = NULL; + fscache_raise_event(object, event); + spin_unlock(&object->lock); + + if (atomic_dec_and_test(&cookie->usage)) + /* the cookie refcount shouldn't be reduced to 0 yet */ + BUG(); + } + + spin_unlock(&cookie->lock); + + if (cookie->parent) { + ASSERTCMP(atomic_read(&cookie->parent->usage), >, 0); + ASSERTCMP(atomic_read(&cookie->parent->n_children), >, 0); + atomic_dec(&cookie->parent->n_children); + } + + /* finally dispose of the cookie */ + ASSERTCMP(atomic_read(&cookie->usage), >, 0); + fscache_cookie_put(cookie); + + _leave(""); +} +EXPORT_SYMBOL(__fscache_relinquish_cookie); + /* * destroy a cookie */ diff --git a/include/linux/fscache.h b/include/linux/fscache.h index b195c2e1ef6..245b48646ef 100644 --- a/include/linux/fscache.h +++ b/include/linux/fscache.h @@ -178,6 +178,13 @@ extern void __fscache_unregister_netfs(struct fscache_netfs *); extern struct fscache_cache_tag *__fscache_lookup_cache_tag(const char *); extern void __fscache_release_cache_tag(struct fscache_cache_tag *); +extern struct fscache_cookie *__fscache_acquire_cookie( + struct fscache_cookie *, + const struct fscache_cookie_def *, + void *); +extern void __fscache_relinquish_cookie(struct fscache_cookie *, int); +extern void __fscache_update_cookie(struct fscache_cookie *); + /** * fscache_register_netfs - Register a filesystem as desiring caching services * @netfs: The description of the filesystem @@ -269,7 +276,10 @@ struct fscache_cookie *fscache_acquire_cookie( const struct fscache_cookie_def *def, void *netfs_data) { - return NULL; + if (fscache_cookie_valid(parent)) + return __fscache_acquire_cookie(parent, def, netfs_data); + else + return NULL; } /** @@ -287,6 +297,8 @@ struct fscache_cookie *fscache_acquire_cookie( static inline void fscache_relinquish_cookie(struct fscache_cookie *cookie, int retire) { + if (fscache_cookie_valid(cookie)) + __fscache_relinquish_cookie(cookie, retire); } /** @@ -302,6 +314,8 @@ void fscache_relinquish_cookie(struct fscache_cookie *cookie, int retire) static inline void fscache_update_cookie(struct fscache_cookie *cookie) { + if (fscache_cookie_valid(cookie)) + __fscache_update_cookie(cookie); } /** -- cgit v1.2.3-70-g09d2 From 952efe7b7840e1c726ae88222245e4efe6bd88f3 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:39 +0100 Subject: FS-Cache: Add and document asynchronous operation handling Add and document asynchronous operation handling for use by FS-Cache's data storage and retrieval routines. The following documentation is added to: Documentation/filesystems/caching/operations.txt ================================ ASYNCHRONOUS OPERATIONS HANDLING ================================ ======== OVERVIEW ======== FS-Cache has an asynchronous operations handling facility that it uses for its data storage and retrieval routines. Its operations are represented by fscache_operation structs, though these are usually embedded into some other structure. This facility is available to and expected to be be used by the cache backends, and FS-Cache will create operations and pass them off to the appropriate cache backend for completion. To make use of this facility, should be #included. =============================== OPERATION RECORD INITIALISATION =============================== An operation is recorded in an fscache_operation struct: struct fscache_operation { union { struct work_struct fast_work; struct slow_work slow_work; }; unsigned long flags; fscache_operation_processor_t processor; ... }; Someone wanting to issue an operation should allocate something with this struct embedded in it. They should initialise it by calling: void fscache_operation_init(struct fscache_operation *op, fscache_operation_release_t release); with the operation to be initialised and the release function to use. The op->flags parameter should be set to indicate the CPU time provision and the exclusivity (see the Parameters section). The op->fast_work, op->slow_work and op->processor flags should be set as appropriate for the CPU time provision (see the Parameters section). FSCACHE_OP_WAITING may be set in op->flags prior to each submission of the operation and waited for afterwards. ========== PARAMETERS ========== There are a number of parameters that can be set in the operation record's flag parameter. There are three options for the provision of CPU time in these operations: (1) The operation may be done synchronously (FSCACHE_OP_MYTHREAD). A thread may decide it wants to handle an operation itself without deferring it to another thread. This is, for example, used in read operations for calling readpages() on the backing filesystem in CacheFiles. Although readpages() does an asynchronous data fetch, the determination of whether pages exist is done synchronously - and the netfs does not proceed until this has been determined. If this option is to be used, FSCACHE_OP_WAITING must be set in op->flags before submitting the operation, and the operating thread must wait for it to be cleared before proceeding: wait_on_bit(&op->flags, FSCACHE_OP_WAITING, fscache_wait_bit, TASK_UNINTERRUPTIBLE); (2) The operation may be fast asynchronous (FSCACHE_OP_FAST), in which case it will be given to keventd to process. Such an operation is not permitted to sleep on I/O. This is, for example, used by CacheFiles to copy data from a backing fs page to a netfs page after the backing fs has read the page in. If this option is used, op->fast_work and op->processor must be initialised before submitting the operation: INIT_WORK(&op->fast_work, do_some_work); (3) The operation may be slow asynchronous (FSCACHE_OP_SLOW), in which case it will be given to the slow work facility to process. Such an operation is permitted to sleep on I/O. This is, for example, used by FS-Cache to handle background writes of pages that have just been fetched from a remote server. If this option is used, op->slow_work and op->processor must be initialised before submitting the operation: fscache_operation_init_slow(op, processor) Furthermore, operations may be one of two types: (1) Exclusive (FSCACHE_OP_EXCLUSIVE). Operations of this type may not run in conjunction with any other operation on the object being operated upon. An example of this is the attribute change operation, in which the file being written to may need truncation. (2) Shareable. Operations of this type may be running simultaneously. It's up to the operation implementation to prevent interference between other operations running at the same time. ========= PROCEDURE ========= Operations are used through the following procedure: (1) The submitting thread must allocate the operation and initialise it itself. Normally this would be part of a more specific structure with the generic op embedded within. (2) The submitting thread must then submit the operation for processing using one of the following two functions: int fscache_submit_op(struct fscache_object *object, struct fscache_operation *op); int fscache_submit_exclusive_op(struct fscache_object *object, struct fscache_operation *op); The first function should be used to submit non-exclusive ops and the second to submit exclusive ones. The caller must still set the FSCACHE_OP_EXCLUSIVE flag. If successful, both functions will assign the operation to the specified object and return 0. -ENOBUFS will be returned if the object specified is permanently unavailable. The operation manager will defer operations on an object that is still undergoing lookup or creation. The operation will also be deferred if an operation of conflicting exclusivity is in progress on the object. If the operation is asynchronous, the manager will retain a reference to it, so the caller should put their reference to it by passing it to: void fscache_put_operation(struct fscache_operation *op); (3) If the submitting thread wants to do the work itself, and has marked the operation with FSCACHE_OP_MYTHREAD, then it should monitor FSCACHE_OP_WAITING as described above and check the state of the object if necessary (the object might have died whilst the thread was waiting). When it has finished doing its processing, it should call fscache_put_operation() on it. (4) The operation holds an effective lock upon the object, preventing other exclusive ops conflicting until it is released. The operation can be enqueued for further immediate asynchronous processing by adjusting the CPU time provisioning option if necessary, eg: op->flags &= ~FSCACHE_OP_TYPE; op->flags |= ~FSCACHE_OP_FAST; and calling: void fscache_enqueue_operation(struct fscache_operation *op) This can be used to allow other things to have use of the worker thread pools. ===================== ASYNCHRONOUS CALLBACK ===================== When used in asynchronous mode, the worker thread pool will invoke the processor method with a pointer to the operation. This should then get at the container struct by using container_of(): static void fscache_write_op(struct fscache_operation *_op) { struct fscache_storage *op = container_of(_op, struct fscache_storage, op); ... } The caller holds a reference on the operation, and will invoke fscache_put_operation() when the processor function returns. The processor function is at liberty to call fscache_enqueue_operation() or to take extra references. Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Al Viro Tested-by: Daire Byrne --- Documentation/filesystems/caching/operations.txt | 213 +++++++++++ fs/fscache/Makefile | 3 +- fs/fscache/cache.c | 2 +- fs/fscache/internal.h | 8 +- fs/fscache/operation.c | 459 +++++++++++++++++++++++ 5 files changed, 682 insertions(+), 3 deletions(-) create mode 100644 Documentation/filesystems/caching/operations.txt create mode 100644 fs/fscache/operation.c (limited to 'fs') diff --git a/Documentation/filesystems/caching/operations.txt b/Documentation/filesystems/caching/operations.txt new file mode 100644 index 00000000000..b6b070c57cb --- /dev/null +++ b/Documentation/filesystems/caching/operations.txt @@ -0,0 +1,213 @@ + ================================ + ASYNCHRONOUS OPERATIONS HANDLING + ================================ + +By: David Howells + +Contents: + + (*) Overview. + + (*) Operation record initialisation. + + (*) Parameters. + + (*) Procedure. + + (*) Asynchronous callback. + + +======== +OVERVIEW +======== + +FS-Cache has an asynchronous operations handling facility that it uses for its +data storage and retrieval routines. Its operations are represented by +fscache_operation structs, though these are usually embedded into some other +structure. + +This facility is available to and expected to be be used by the cache backends, +and FS-Cache will create operations and pass them off to the appropriate cache +backend for completion. + +To make use of this facility, should be #included. + + +=============================== +OPERATION RECORD INITIALISATION +=============================== + +An operation is recorded in an fscache_operation struct: + + struct fscache_operation { + union { + struct work_struct fast_work; + struct slow_work slow_work; + }; + unsigned long flags; + fscache_operation_processor_t processor; + ... + }; + +Someone wanting to issue an operation should allocate something with this +struct embedded in it. They should initialise it by calling: + + void fscache_operation_init(struct fscache_operation *op, + fscache_operation_release_t release); + +with the operation to be initialised and the release function to use. + +The op->flags parameter should be set to indicate the CPU time provision and +the exclusivity (see the Parameters section). + +The op->fast_work, op->slow_work and op->processor flags should be set as +appropriate for the CPU time provision (see the Parameters section). + +FSCACHE_OP_WAITING may be set in op->flags prior to each submission of the +operation and waited for afterwards. + + +========== +PARAMETERS +========== + +There are a number of parameters that can be set in the operation record's flag +parameter. There are three options for the provision of CPU time in these +operations: + + (1) The operation may be done synchronously (FSCACHE_OP_MYTHREAD). A thread + may decide it wants to handle an operation itself without deferring it to + another thread. + + This is, for example, used in read operations for calling readpages() on + the backing filesystem in CacheFiles. Although readpages() does an + asynchronous data fetch, the determination of whether pages exist is done + synchronously - and the netfs does not proceed until this has been + determined. + + If this option is to be used, FSCACHE_OP_WAITING must be set in op->flags + before submitting the operation, and the operating thread must wait for it + to be cleared before proceeding: + + wait_on_bit(&op->flags, FSCACHE_OP_WAITING, + fscache_wait_bit, TASK_UNINTERRUPTIBLE); + + + (2) The operation may be fast asynchronous (FSCACHE_OP_FAST), in which case it + will be given to keventd to process. Such an operation is not permitted + to sleep on I/O. + + This is, for example, used by CacheFiles to copy data from a backing fs + page to a netfs page after the backing fs has read the page in. + + If this option is used, op->fast_work and op->processor must be + initialised before submitting the operation: + + INIT_WORK(&op->fast_work, do_some_work); + + + (3) The operation may be slow asynchronous (FSCACHE_OP_SLOW), in which case it + will be given to the slow work facility to process. Such an operation is + permitted to sleep on I/O. + + This is, for example, used by FS-Cache to handle background writes of + pages that have just been fetched from a remote server. + + If this option is used, op->slow_work and op->processor must be + initialised before submitting the operation: + + fscache_operation_init_slow(op, processor) + + +Furthermore, operations may be one of two types: + + (1) Exclusive (FSCACHE_OP_EXCLUSIVE). Operations of this type may not run in + conjunction with any other operation on the object being operated upon. + + An example of this is the attribute change operation, in which the file + being written to may need truncation. + + (2) Shareable. Operations of this type may be running simultaneously. It's + up to the operation implementation to prevent interference between other + operations running at the same time. + + +========= +PROCEDURE +========= + +Operations are used through the following procedure: + + (1) The submitting thread must allocate the operation and initialise it + itself. Normally this would be part of a more specific structure with the + generic op embedded within. + + (2) The submitting thread must then submit the operation for processing using + one of the following two functions: + + int fscache_submit_op(struct fscache_object *object, + struct fscache_operation *op); + + int fscache_submit_exclusive_op(struct fscache_object *object, + struct fscache_operation *op); + + The first function should be used to submit non-exclusive ops and the + second to submit exclusive ones. The caller must still set the + FSCACHE_OP_EXCLUSIVE flag. + + If successful, both functions will assign the operation to the specified + object and return 0. -ENOBUFS will be returned if the object specified is + permanently unavailable. + + The operation manager will defer operations on an object that is still + undergoing lookup or creation. The operation will also be deferred if an + operation of conflicting exclusivity is in progress on the object. + + If the operation is asynchronous, the manager will retain a reference to + it, so the caller should put their reference to it by passing it to: + + void fscache_put_operation(struct fscache_operation *op); + + (3) If the submitting thread wants to do the work itself, and has marked the + operation with FSCACHE_OP_MYTHREAD, then it should monitor + FSCACHE_OP_WAITING as described above and check the state of the object if + necessary (the object might have died whilst the thread was waiting). + + When it has finished doing its processing, it should call + fscache_put_operation() on it. + + (4) The operation holds an effective lock upon the object, preventing other + exclusive ops conflicting until it is released. The operation can be + enqueued for further immediate asynchronous processing by adjusting the + CPU time provisioning option if necessary, eg: + + op->flags &= ~FSCACHE_OP_TYPE; + op->flags |= ~FSCACHE_OP_FAST; + + and calling: + + void fscache_enqueue_operation(struct fscache_operation *op) + + This can be used to allow other things to have use of the worker thread + pools. + + +===================== +ASYNCHRONOUS CALLBACK +===================== + +When used in asynchronous mode, the worker thread pool will invoke the +processor method with a pointer to the operation. This should then get at the +container struct by using container_of(): + + static void fscache_write_op(struct fscache_operation *_op) + { + struct fscache_storage *op = + container_of(_op, struct fscache_storage, op); + ... + } + +The caller holds a reference on the operation, and will invoke +fscache_put_operation() when the processor function returns. The processor +function is at liberty to call fscache_enqueue_operation() or to take extra +references. diff --git a/fs/fscache/Makefile b/fs/fscache/Makefile index 4420ac6ea10..6f82da2aa9d 100644 --- a/fs/fscache/Makefile +++ b/fs/fscache/Makefile @@ -8,7 +8,8 @@ fscache-y := \ fsdef.o \ main.o \ netfs.o \ - object.o + object.o \ + operation.o fscache-$(CONFIG_PROC_FS) += proc.o fscache-$(CONFIG_FSCACHE_STATS) += stats.o diff --git a/fs/fscache/cache.c b/fs/fscache/cache.c index 355172f785f..e21985bbb1f 100644 --- a/fs/fscache/cache.c +++ b/fs/fscache/cache.c @@ -194,7 +194,7 @@ void fscache_init_cache(struct fscache_cache *cache, vsnprintf(cache->identifier, sizeof(cache->identifier), idfmt, va); va_end(va); - INIT_WORK(&cache->op_gc, NULL); + INIT_WORK(&cache->op_gc, fscache_operation_gc); INIT_LIST_HEAD(&cache->link); INIT_LIST_HEAD(&cache->object_list); INIT_LIST_HEAD(&cache->op_gc_list); diff --git a/fs/fscache/internal.h b/fs/fscache/internal.h index 529f4de328c..014a830c8b3 100644 --- a/fs/fscache/internal.h +++ b/fs/fscache/internal.h @@ -95,7 +95,13 @@ extern void fscache_enqueue_object(struct fscache_object *); /* * fsc-operation.c */ -#define fscache_start_operations(obj) BUG() +extern int fscache_submit_exclusive_op(struct fscache_object *, + struct fscache_operation *); +extern int fscache_submit_op(struct fscache_object *, + struct fscache_operation *); +extern void fscache_abort_object(struct fscache_object *); +extern void fscache_start_operations(struct fscache_object *); +extern void fscache_operation_gc(struct work_struct *); /* * fsc-proc.c diff --git a/fs/fscache/operation.c b/fs/fscache/operation.c new file mode 100644 index 00000000000..e7f8d53b8b6 --- /dev/null +++ b/fs/fscache/operation.c @@ -0,0 +1,459 @@ +/* FS-Cache worker operation management routines + * + * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + * See Documentation/filesystems/caching/operations.txt + */ + +#define FSCACHE_DEBUG_LEVEL OPERATION +#include +#include "internal.h" + +atomic_t fscache_op_debug_id; +EXPORT_SYMBOL(fscache_op_debug_id); + +/** + * fscache_enqueue_operation - Enqueue an operation for processing + * @op: The operation to enqueue + * + * Enqueue an operation for processing by the FS-Cache thread pool. + * + * This will get its own ref on the object. + */ +void fscache_enqueue_operation(struct fscache_operation *op) +{ + _enter("{OBJ%x OP%x,%u}", + op->object->debug_id, op->debug_id, atomic_read(&op->usage)); + + ASSERT(op->processor != NULL); + ASSERTCMP(op->object->state, >=, FSCACHE_OBJECT_AVAILABLE); + ASSERTCMP(atomic_read(&op->usage), >, 0); + + if (list_empty(&op->pend_link)) { + switch (op->flags & FSCACHE_OP_TYPE) { + case FSCACHE_OP_FAST: + _debug("queue fast"); + atomic_inc(&op->usage); + if (!schedule_work(&op->fast_work)) + fscache_put_operation(op); + break; + case FSCACHE_OP_SLOW: + _debug("queue slow"); + slow_work_enqueue(&op->slow_work); + break; + case FSCACHE_OP_MYTHREAD: + _debug("queue for caller's attention"); + break; + default: + printk(KERN_ERR "FS-Cache: Unexpected op type %lx", + op->flags); + BUG(); + break; + } + fscache_stat(&fscache_n_op_enqueue); + } +} +EXPORT_SYMBOL(fscache_enqueue_operation); + +/* + * start an op running + */ +static void fscache_run_op(struct fscache_object *object, + struct fscache_operation *op) +{ + object->n_in_progress++; + if (test_and_clear_bit(FSCACHE_OP_WAITING, &op->flags)) + wake_up_bit(&op->flags, FSCACHE_OP_WAITING); + if (op->processor) + fscache_enqueue_operation(op); + fscache_stat(&fscache_n_op_run); +} + +/* + * submit an exclusive operation for an object + * - other ops are excluded from running simultaneously with this one + * - this gets any extra refs it needs on an op + */ +int fscache_submit_exclusive_op(struct fscache_object *object, + struct fscache_operation *op) +{ + int ret; + + _enter("{OBJ%x OP%x},", object->debug_id, op->debug_id); + + spin_lock(&object->lock); + ASSERTCMP(object->n_ops, >=, object->n_in_progress); + ASSERTCMP(object->n_ops, >=, object->n_exclusive); + + ret = -ENOBUFS; + if (fscache_object_is_active(object)) { + op->object = object; + object->n_ops++; + object->n_exclusive++; /* reads and writes must wait */ + + if (object->n_ops > 0) { + atomic_inc(&op->usage); + list_add_tail(&op->pend_link, &object->pending_ops); + fscache_stat(&fscache_n_op_pend); + } else if (!list_empty(&object->pending_ops)) { + atomic_inc(&op->usage); + list_add_tail(&op->pend_link, &object->pending_ops); + fscache_stat(&fscache_n_op_pend); + fscache_start_operations(object); + } else { + ASSERTCMP(object->n_in_progress, ==, 0); + fscache_run_op(object, op); + } + + /* need to issue a new write op after this */ + clear_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags); + ret = 0; + } else if (object->state == FSCACHE_OBJECT_CREATING) { + op->object = object; + object->n_ops++; + object->n_exclusive++; /* reads and writes must wait */ + atomic_inc(&op->usage); + list_add_tail(&op->pend_link, &object->pending_ops); + fscache_stat(&fscache_n_op_pend); + ret = 0; + } else { + /* not allowed to submit ops in any other state */ + BUG(); + } + + spin_unlock(&object->lock); + return ret; +} + +/* + * report an unexpected submission + */ +static void fscache_report_unexpected_submission(struct fscache_object *object, + struct fscache_operation *op, + unsigned long ostate) +{ + static bool once_only; + struct fscache_operation *p; + unsigned n; + + if (once_only) + return; + once_only = true; + + kdebug("unexpected submission OP%x [OBJ%x %s]", + op->debug_id, object->debug_id, + fscache_object_states[object->state]); + kdebug("objstate=%s [%s]", + fscache_object_states[object->state], + fscache_object_states[ostate]); + kdebug("objflags=%lx", object->flags); + kdebug("objevent=%lx [%lx]", object->events, object->event_mask); + kdebug("ops=%u inp=%u exc=%u", + object->n_ops, object->n_in_progress, object->n_exclusive); + + if (!list_empty(&object->pending_ops)) { + n = 0; + list_for_each_entry(p, &object->pending_ops, pend_link) { + ASSERTCMP(p->object, ==, object); + kdebug("%p %p", op->processor, op->release); + n++; + } + + kdebug("n=%u", n); + } + + dump_stack(); +} + +/* + * submit an operation for an object + * - objects may be submitted only in the following states: + * - during object creation (write ops may be submitted) + * - whilst the object is active + * - after an I/O error incurred in one of the two above states (op rejected) + * - this gets any extra refs it needs on an op + */ +int fscache_submit_op(struct fscache_object *object, + struct fscache_operation *op) +{ + unsigned long ostate; + int ret; + + _enter("{OBJ%x OP%x},{%u}", + object->debug_id, op->debug_id, atomic_read(&op->usage)); + + ASSERTCMP(atomic_read(&op->usage), >, 0); + + spin_lock(&object->lock); + ASSERTCMP(object->n_ops, >=, object->n_in_progress); + ASSERTCMP(object->n_ops, >=, object->n_exclusive); + + ostate = object->state; + smp_rmb(); + + if (fscache_object_is_active(object)) { + op->object = object; + object->n_ops++; + + if (object->n_exclusive > 0) { + atomic_inc(&op->usage); + list_add_tail(&op->pend_link, &object->pending_ops); + fscache_stat(&fscache_n_op_pend); + } else if (!list_empty(&object->pending_ops)) { + atomic_inc(&op->usage); + list_add_tail(&op->pend_link, &object->pending_ops); + fscache_stat(&fscache_n_op_pend); + fscache_start_operations(object); + } else { + ASSERTCMP(object->n_exclusive, ==, 0); + fscache_run_op(object, op); + } + ret = 0; + } else if (object->state == FSCACHE_OBJECT_CREATING) { + op->object = object; + object->n_ops++; + atomic_inc(&op->usage); + list_add_tail(&op->pend_link, &object->pending_ops); + fscache_stat(&fscache_n_op_pend); + ret = 0; + } else if (!test_bit(FSCACHE_IOERROR, &object->cache->flags)) { + fscache_report_unexpected_submission(object, op, ostate); + ASSERT(!fscache_object_is_active(object)); + ret = -ENOBUFS; + } else { + ret = -ENOBUFS; + } + + spin_unlock(&object->lock); + return ret; +} + +/* + * queue an object for withdrawal on error, aborting all following asynchronous + * operations + */ +void fscache_abort_object(struct fscache_object *object) +{ + _enter("{OBJ%x}", object->debug_id); + + fscache_raise_event(object, FSCACHE_OBJECT_EV_ERROR); +} + +/* + * jump start the operation processing on an object + * - caller must hold object->lock + */ +void fscache_start_operations(struct fscache_object *object) +{ + struct fscache_operation *op; + bool stop = false; + + while (!list_empty(&object->pending_ops) && !stop) { + op = list_entry(object->pending_ops.next, + struct fscache_operation, pend_link); + + if (test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags)) { + if (object->n_in_progress > 0) + break; + stop = true; + } + list_del_init(&op->pend_link); + object->n_in_progress++; + + if (test_and_clear_bit(FSCACHE_OP_WAITING, &op->flags)) + wake_up_bit(&op->flags, FSCACHE_OP_WAITING); + if (op->processor) + fscache_enqueue_operation(op); + + /* the pending queue was holding a ref on the object */ + fscache_put_operation(op); + } + + ASSERTCMP(object->n_in_progress, <=, object->n_ops); + + _debug("woke %d ops on OBJ%x", + object->n_in_progress, object->debug_id); +} + +/* + * release an operation + * - queues pending ops if this is the last in-progress op + */ +void fscache_put_operation(struct fscache_operation *op) +{ + struct fscache_object *object; + struct fscache_cache *cache; + + _enter("{OBJ%x OP%x,%d}", + op->object->debug_id, op->debug_id, atomic_read(&op->usage)); + + ASSERTCMP(atomic_read(&op->usage), >, 0); + + if (!atomic_dec_and_test(&op->usage)) + return; + + _debug("PUT OP"); + if (test_and_set_bit(FSCACHE_OP_DEAD, &op->flags)) + BUG(); + + fscache_stat(&fscache_n_op_release); + + if (op->release) { + op->release(op); + op->release = NULL; + } + + object = op->object; + + /* now... we may get called with the object spinlock held, so we + * complete the cleanup here only if we can immediately acquire the + * lock, and defer it otherwise */ + if (!spin_trylock(&object->lock)) { + _debug("defer put"); + fscache_stat(&fscache_n_op_deferred_release); + + cache = object->cache; + spin_lock(&cache->op_gc_list_lock); + list_add_tail(&op->pend_link, &cache->op_gc_list); + spin_unlock(&cache->op_gc_list_lock); + schedule_work(&cache->op_gc); + _leave(" [defer]"); + return; + } + + if (test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags)) { + ASSERTCMP(object->n_exclusive, >, 0); + object->n_exclusive--; + } + + ASSERTCMP(object->n_in_progress, >, 0); + object->n_in_progress--; + if (object->n_in_progress == 0) + fscache_start_operations(object); + + ASSERTCMP(object->n_ops, >, 0); + object->n_ops--; + if (object->n_ops == 0) + fscache_raise_event(object, FSCACHE_OBJECT_EV_CLEARED); + + spin_unlock(&object->lock); + + kfree(op); + _leave(" [done]"); +} +EXPORT_SYMBOL(fscache_put_operation); + +/* + * garbage collect operations that have had their release deferred + */ +void fscache_operation_gc(struct work_struct *work) +{ + struct fscache_operation *op; + struct fscache_object *object; + struct fscache_cache *cache = + container_of(work, struct fscache_cache, op_gc); + int count = 0; + + _enter(""); + + do { + spin_lock(&cache->op_gc_list_lock); + if (list_empty(&cache->op_gc_list)) { + spin_unlock(&cache->op_gc_list_lock); + break; + } + + op = list_entry(cache->op_gc_list.next, + struct fscache_operation, pend_link); + list_del(&op->pend_link); + spin_unlock(&cache->op_gc_list_lock); + + object = op->object; + + _debug("GC DEFERRED REL OBJ%x OP%x", + object->debug_id, op->debug_id); + fscache_stat(&fscache_n_op_gc); + + ASSERTCMP(atomic_read(&op->usage), ==, 0); + + spin_lock(&object->lock); + if (test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags)) { + ASSERTCMP(object->n_exclusive, >, 0); + object->n_exclusive--; + } + + ASSERTCMP(object->n_in_progress, >, 0); + object->n_in_progress--; + if (object->n_in_progress == 0) + fscache_start_operations(object); + + ASSERTCMP(object->n_ops, >, 0); + object->n_ops--; + if (object->n_ops == 0) + fscache_raise_event(object, FSCACHE_OBJECT_EV_CLEARED); + + spin_unlock(&object->lock); + + } while (count++ < 20); + + if (!list_empty(&cache->op_gc_list)) + schedule_work(&cache->op_gc); + + _leave(""); +} + +/* + * allow the slow work item processor to get a ref on an operation + */ +static int fscache_op_get_ref(struct slow_work *work) +{ + struct fscache_operation *op = + container_of(work, struct fscache_operation, slow_work); + + atomic_inc(&op->usage); + return 0; +} + +/* + * allow the slow work item processor to discard a ref on an operation + */ +static void fscache_op_put_ref(struct slow_work *work) +{ + struct fscache_operation *op = + container_of(work, struct fscache_operation, slow_work); + + fscache_put_operation(op); +} + +/* + * execute an operation using the slow thread pool to provide processing context + * - the caller holds a ref to this object, so we don't need to hold one + */ +static void fscache_op_execute(struct slow_work *work) +{ + struct fscache_operation *op = + container_of(work, struct fscache_operation, slow_work); + unsigned long start; + + _enter("{OBJ%x OP%x,%d}", + op->object->debug_id, op->debug_id, atomic_read(&op->usage)); + + ASSERT(op->processor != NULL); + start = jiffies; + op->processor(op); + fscache_hist(fscache_ops_histogram, start); + + _leave(""); +} + +const struct slow_work_ops fscache_op_slow_work_ops = { + .get_ref = fscache_op_get_ref, + .put_ref = fscache_op_put_ref, + .execute = fscache_op_execute, +}; -- cgit v1.2.3-70-g09d2 From b510882281d56873e1194021643b7c325336f84f Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:39 +0100 Subject: FS-Cache: Implement data I/O part of netfs API Implement the data I/O part of the FS-Cache netfs API. The documentation and API header file were added in a previous patch. This patch implements the following functions for the netfs to call: (*) fscache_attr_changed(). Indicate that the object has changed its attributes. The only attribute currently recorded is the file size. Only pages within the set file size will be stored in the cache. This operation is submitted for asynchronous processing, and will return immediately. It will return -ENOMEM if an out of memory error is encountered, -ENOBUFS if the object is not actually cached, or 0 if the operation is successfully queued. (*) fscache_read_or_alloc_page(). (*) fscache_read_or_alloc_pages(). Request data be fetched from the disk, and allocate internal metadata to track the netfs pages and reserve disk space for unknown pages. These operations perform semi-asynchronous data reads. Upon returning they will indicate which pages they think can be retrieved from disk, and will have set in progress attempts to retrieve those pages. These will return, in order of preference, -ENOMEM on memory allocation error, -ERESTARTSYS if a signal interrupted proceedings, -ENODATA if one or more requested pages are not yet cached, -ENOBUFS if the object is not actually cached or if there isn't space for future pages to be cached on this object, or 0 if successful. In the case of the multipage function, the pages for which reads are set in progress will be removed from the list and the page count decreased appropriately. If any read operations should fail, the completion function will be given an error, and will also be passed contextual information to allow the netfs to fall back to querying the server for the absent pages. For each successful read, the page completion function will also be called. Any pages subsequently tracked by the cache will have PG_fscache set upon them on return. fscache_uncache_page() must be called for such pages. If supplied by the netfs, the mark_pages_cached() cookie op will be invoked for any pages now tracked. (*) fscache_alloc_page(). Allocate internal metadata to track a netfs page and reserve disk space. This will return -ENOMEM on memory allocation error, -ERESTARTSYS on signal, -ENOBUFS if the object isn't cached, or there isn't enough space in the cache, or 0 if successful. Any pages subsequently tracked by the cache will have PG_fscache set upon them on return. fscache_uncache_page() must be called for such pages. If supplied by the netfs, the mark_pages_cached() cookie op will be invoked for any pages now tracked. (*) fscache_write_page(). Request data be stored to disk. This may only be called on pages that have been read or alloc'd by the above three functions and have not yet been uncached. This will return -ENOMEM on memory allocation error, -ERESTARTSYS on signal, -ENOBUFS if the object isn't cached, or there isn't immediately enough space in the cache, or 0 if successful. On a successful return, this operation will have queued the page for asynchronous writing to the cache. The page will be returned with PG_fscache_write set until the write completes one way or another. The caller will not be notified if the write fails due to an I/O error. If that happens, the object will become available and all pending writes will be aborted. Note that the cache may batch up page writes, and so it may take a while to get around to writing them out. The caller must assume that until PG_fscache_write is cleared the page is use by the cache. Any changes made to the page may be reflected on disk. The page may even be under DMA. (*) fscache_uncache_page(). Indicate that the cache should stop tracking a page previously read or alloc'd from the cache. If the page was alloc'd only, but unwritten, it will not appear on disk. Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Al Viro Tested-by: Daire Byrne --- fs/fscache/Makefile | 3 +- fs/fscache/internal.h | 21 ++ fs/fscache/page.c | 816 ++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/fscache.h | 52 ++- 4 files changed, 886 insertions(+), 6 deletions(-) create mode 100644 fs/fscache/page.c (limited to 'fs') diff --git a/fs/fscache/Makefile b/fs/fscache/Makefile index 6f82da2aa9d..91571b95aac 100644 --- a/fs/fscache/Makefile +++ b/fs/fscache/Makefile @@ -9,7 +9,8 @@ fscache-y := \ main.o \ netfs.o \ object.o \ - operation.o + operation.o \ + page.o fscache-$(CONFIG_PROC_FS) += proc.o fscache-$(CONFIG_FSCACHE_STATS) += stats.o diff --git a/fs/fscache/internal.h b/fs/fscache/internal.h index 014a830c8b3..e0cbd16f6dc 100644 --- a/fs/fscache/internal.h +++ b/fs/fscache/internal.h @@ -229,6 +229,27 @@ static inline void fscache_cookie_put(struct fscache_cookie *cookie) __fscache_cookie_put(cookie); } +/* + * get an extra reference to a netfs retrieval context + */ +static inline +void *fscache_get_context(struct fscache_cookie *cookie, void *context) +{ + if (cookie->def->get_context) + cookie->def->get_context(cookie->netfs_data, context); + return context; +} + +/* + * release a reference to a netfs retrieval context + */ +static inline +void fscache_put_context(struct fscache_cookie *cookie, void *context) +{ + if (cookie->def->put_context) + cookie->def->put_context(cookie->netfs_data, context); +} + /*****************************************************************************/ /* * debug tracing diff --git a/fs/fscache/page.c b/fs/fscache/page.c new file mode 100644 index 00000000000..2568e0eb644 --- /dev/null +++ b/fs/fscache/page.c @@ -0,0 +1,816 @@ +/* Cache page management and data I/O routines + * + * Copyright (C) 2004-2008 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#define FSCACHE_DEBUG_LEVEL PAGE +#include +#include +#include +#include +#include "internal.h" + +/* + * check to see if a page is being written to the cache + */ +bool __fscache_check_page_write(struct fscache_cookie *cookie, struct page *page) +{ + void *val; + + rcu_read_lock(); + val = radix_tree_lookup(&cookie->stores, page->index); + rcu_read_unlock(); + + return val != NULL; +} +EXPORT_SYMBOL(__fscache_check_page_write); + +/* + * wait for a page to finish being written to the cache + */ +void __fscache_wait_on_page_write(struct fscache_cookie *cookie, struct page *page) +{ + wait_queue_head_t *wq = bit_waitqueue(&cookie->flags, 0); + + wait_event(*wq, !__fscache_check_page_write(cookie, page)); +} +EXPORT_SYMBOL(__fscache_wait_on_page_write); + +/* + * note that a page has finished being written to the cache + */ +static void fscache_end_page_write(struct fscache_cookie *cookie, struct page *page) +{ + struct page *xpage; + + spin_lock(&cookie->lock); + xpage = radix_tree_delete(&cookie->stores, page->index); + spin_unlock(&cookie->lock); + ASSERT(xpage != NULL); + + wake_up_bit(&cookie->flags, 0); +} + +/* + * actually apply the changed attributes to a cache object + */ +static void fscache_attr_changed_op(struct fscache_operation *op) +{ + struct fscache_object *object = op->object; + + _enter("{OBJ%x OP%x}", object->debug_id, op->debug_id); + + fscache_stat(&fscache_n_attr_changed_calls); + + if (fscache_object_is_active(object) && + object->cache->ops->attr_changed(object) < 0) + fscache_abort_object(object); + + _leave(""); +} + +/* + * notification that the attributes on an object have changed + */ +int __fscache_attr_changed(struct fscache_cookie *cookie) +{ + struct fscache_operation *op; + struct fscache_object *object; + + _enter("%p", cookie); + + ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX); + + fscache_stat(&fscache_n_attr_changed); + + op = kzalloc(sizeof(*op), GFP_KERNEL); + if (!op) { + fscache_stat(&fscache_n_attr_changed_nomem); + _leave(" = -ENOMEM"); + return -ENOMEM; + } + + fscache_operation_init(op, NULL); + fscache_operation_init_slow(op, fscache_attr_changed_op); + op->flags = FSCACHE_OP_SLOW | (1 << FSCACHE_OP_EXCLUSIVE); + + spin_lock(&cookie->lock); + + if (hlist_empty(&cookie->backing_objects)) + goto nobufs; + object = hlist_entry(cookie->backing_objects.first, + struct fscache_object, cookie_link); + + if (fscache_submit_exclusive_op(object, op) < 0) + goto nobufs; + spin_unlock(&cookie->lock); + fscache_stat(&fscache_n_attr_changed_ok); + fscache_put_operation(op); + _leave(" = 0"); + return 0; + +nobufs: + spin_unlock(&cookie->lock); + kfree(op); + fscache_stat(&fscache_n_attr_changed_nobufs); + _leave(" = %d", -ENOBUFS); + return -ENOBUFS; +} +EXPORT_SYMBOL(__fscache_attr_changed); + +/* + * handle secondary execution given to a retrieval op on behalf of the + * cache + */ +static void fscache_retrieval_work(struct work_struct *work) +{ + struct fscache_retrieval *op = + container_of(work, struct fscache_retrieval, op.fast_work); + unsigned long start; + + _enter("{OP%x}", op->op.debug_id); + + start = jiffies; + op->op.processor(&op->op); + fscache_hist(fscache_ops_histogram, start); + fscache_put_operation(&op->op); +} + +/* + * release a retrieval op reference + */ +static void fscache_release_retrieval_op(struct fscache_operation *_op) +{ + struct fscache_retrieval *op = + container_of(_op, struct fscache_retrieval, op); + + _enter("{OP%x}", op->op.debug_id); + + fscache_hist(fscache_retrieval_histogram, op->start_time); + if (op->context) + fscache_put_context(op->op.object->cookie, op->context); + + _leave(""); +} + +/* + * allocate a retrieval op + */ +static struct fscache_retrieval *fscache_alloc_retrieval( + struct address_space *mapping, + fscache_rw_complete_t end_io_func, + void *context) +{ + struct fscache_retrieval *op; + + /* allocate a retrieval operation and attempt to submit it */ + op = kzalloc(sizeof(*op), GFP_NOIO); + if (!op) { + fscache_stat(&fscache_n_retrievals_nomem); + return NULL; + } + + fscache_operation_init(&op->op, fscache_release_retrieval_op); + op->op.flags = FSCACHE_OP_MYTHREAD | (1 << FSCACHE_OP_WAITING); + op->mapping = mapping; + op->end_io_func = end_io_func; + op->context = context; + op->start_time = jiffies; + INIT_WORK(&op->op.fast_work, fscache_retrieval_work); + INIT_LIST_HEAD(&op->to_do); + return op; +} + +/* + * wait for a deferred lookup to complete + */ +static int fscache_wait_for_deferred_lookup(struct fscache_cookie *cookie) +{ + unsigned long jif; + + _enter(""); + + if (!test_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags)) { + _leave(" = 0 [imm]"); + return 0; + } + + fscache_stat(&fscache_n_retrievals_wait); + + jif = jiffies; + if (wait_on_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP, + fscache_wait_bit_interruptible, + TASK_INTERRUPTIBLE) != 0) { + fscache_stat(&fscache_n_retrievals_intr); + _leave(" = -ERESTARTSYS"); + return -ERESTARTSYS; + } + + ASSERT(!test_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags)); + + smp_rmb(); + fscache_hist(fscache_retrieval_delay_histogram, jif); + _leave(" = 0 [dly]"); + return 0; +} + +/* + * read a page from the cache or allocate a block in which to store it + * - we return: + * -ENOMEM - out of memory, nothing done + * -ERESTARTSYS - interrupted + * -ENOBUFS - no backing object available in which to cache the block + * -ENODATA - no data available in the backing object for this block + * 0 - dispatched a read - it'll call end_io_func() when finished + */ +int __fscache_read_or_alloc_page(struct fscache_cookie *cookie, + struct page *page, + fscache_rw_complete_t end_io_func, + void *context, + gfp_t gfp) +{ + struct fscache_retrieval *op; + struct fscache_object *object; + int ret; + + _enter("%p,%p,,,", cookie, page); + + fscache_stat(&fscache_n_retrievals); + + if (hlist_empty(&cookie->backing_objects)) + goto nobufs; + + ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX); + ASSERTCMP(page, !=, NULL); + + if (fscache_wait_for_deferred_lookup(cookie) < 0) + return -ERESTARTSYS; + + op = fscache_alloc_retrieval(page->mapping, end_io_func, context); + if (!op) { + _leave(" = -ENOMEM"); + return -ENOMEM; + } + + spin_lock(&cookie->lock); + + if (hlist_empty(&cookie->backing_objects)) + goto nobufs_unlock; + object = hlist_entry(cookie->backing_objects.first, + struct fscache_object, cookie_link); + + ASSERTCMP(object->state, >, FSCACHE_OBJECT_LOOKING_UP); + + if (fscache_submit_op(object, &op->op) < 0) + goto nobufs_unlock; + spin_unlock(&cookie->lock); + + fscache_stat(&fscache_n_retrieval_ops); + + /* pin the netfs read context in case we need to do the actual netfs + * read because we've encountered a cache read failure */ + fscache_get_context(object->cookie, op->context); + + /* we wait for the operation to become active, and then process it + * *here*, in this thread, and not in the thread pool */ + if (test_bit(FSCACHE_OP_WAITING, &op->op.flags)) { + _debug(">>> WT"); + fscache_stat(&fscache_n_retrieval_op_waits); + wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING, + fscache_wait_bit, TASK_UNINTERRUPTIBLE); + _debug("<<< GO"); + } + + /* ask the cache to honour the operation */ + if (test_bit(FSCACHE_COOKIE_NO_DATA_YET, &object->cookie->flags)) { + ret = object->cache->ops->allocate_page(op, page, gfp); + if (ret == 0) + ret = -ENODATA; + } else { + ret = object->cache->ops->read_or_alloc_page(op, page, gfp); + } + + if (ret == -ENOMEM) + fscache_stat(&fscache_n_retrievals_nomem); + else if (ret == -ERESTARTSYS) + fscache_stat(&fscache_n_retrievals_intr); + else if (ret == -ENODATA) + fscache_stat(&fscache_n_retrievals_nodata); + else if (ret < 0) + fscache_stat(&fscache_n_retrievals_nobufs); + else + fscache_stat(&fscache_n_retrievals_ok); + + fscache_put_retrieval(op); + _leave(" = %d", ret); + return ret; + +nobufs_unlock: + spin_unlock(&cookie->lock); + kfree(op); +nobufs: + fscache_stat(&fscache_n_retrievals_nobufs); + _leave(" = -ENOBUFS"); + return -ENOBUFS; +} +EXPORT_SYMBOL(__fscache_read_or_alloc_page); + +/* + * read a list of page from the cache or allocate a block in which to store + * them + * - we return: + * -ENOMEM - out of memory, some pages may be being read + * -ERESTARTSYS - interrupted, some pages may be being read + * -ENOBUFS - no backing object or space available in which to cache any + * pages not being read + * -ENODATA - no data available in the backing object for some or all of + * the pages + * 0 - dispatched a read on all pages + * + * end_io_func() will be called for each page read from the cache as it is + * finishes being read + * + * any pages for which a read is dispatched will be removed from pages and + * nr_pages + */ +int __fscache_read_or_alloc_pages(struct fscache_cookie *cookie, + struct address_space *mapping, + struct list_head *pages, + unsigned *nr_pages, + fscache_rw_complete_t end_io_func, + void *context, + gfp_t gfp) +{ + fscache_pages_retrieval_func_t func; + struct fscache_retrieval *op; + struct fscache_object *object; + int ret; + + _enter("%p,,%d,,,", cookie, *nr_pages); + + fscache_stat(&fscache_n_retrievals); + + if (hlist_empty(&cookie->backing_objects)) + goto nobufs; + + ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX); + ASSERTCMP(*nr_pages, >, 0); + ASSERT(!list_empty(pages)); + + if (fscache_wait_for_deferred_lookup(cookie) < 0) + return -ERESTARTSYS; + + op = fscache_alloc_retrieval(mapping, end_io_func, context); + if (!op) + return -ENOMEM; + + spin_lock(&cookie->lock); + + if (hlist_empty(&cookie->backing_objects)) + goto nobufs_unlock; + object = hlist_entry(cookie->backing_objects.first, + struct fscache_object, cookie_link); + + if (fscache_submit_op(object, &op->op) < 0) + goto nobufs_unlock; + spin_unlock(&cookie->lock); + + fscache_stat(&fscache_n_retrieval_ops); + + /* pin the netfs read context in case we need to do the actual netfs + * read because we've encountered a cache read failure */ + fscache_get_context(object->cookie, op->context); + + /* we wait for the operation to become active, and then process it + * *here*, in this thread, and not in the thread pool */ + if (test_bit(FSCACHE_OP_WAITING, &op->op.flags)) { + _debug(">>> WT"); + fscache_stat(&fscache_n_retrieval_op_waits); + wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING, + fscache_wait_bit, TASK_UNINTERRUPTIBLE); + _debug("<<< GO"); + } + + /* ask the cache to honour the operation */ + if (test_bit(FSCACHE_COOKIE_NO_DATA_YET, &object->cookie->flags)) + func = object->cache->ops->allocate_pages; + else + func = object->cache->ops->read_or_alloc_pages; + ret = func(op, pages, nr_pages, gfp); + + if (ret == -ENOMEM) + fscache_stat(&fscache_n_retrievals_nomem); + else if (ret == -ERESTARTSYS) + fscache_stat(&fscache_n_retrievals_intr); + else if (ret == -ENODATA) + fscache_stat(&fscache_n_retrievals_nodata); + else if (ret < 0) + fscache_stat(&fscache_n_retrievals_nobufs); + else + fscache_stat(&fscache_n_retrievals_ok); + + fscache_put_retrieval(op); + _leave(" = %d", ret); + return ret; + +nobufs_unlock: + spin_unlock(&cookie->lock); + kfree(op); +nobufs: + fscache_stat(&fscache_n_retrievals_nobufs); + _leave(" = -ENOBUFS"); + return -ENOBUFS; +} +EXPORT_SYMBOL(__fscache_read_or_alloc_pages); + +/* + * allocate a block in the cache on which to store a page + * - we return: + * -ENOMEM - out of memory, nothing done + * -ERESTARTSYS - interrupted + * -ENOBUFS - no backing object available in which to cache the block + * 0 - block allocated + */ +int __fscache_alloc_page(struct fscache_cookie *cookie, + struct page *page, + gfp_t gfp) +{ + struct fscache_retrieval *op; + struct fscache_object *object; + int ret; + + _enter("%p,%p,,,", cookie, page); + + fscache_stat(&fscache_n_allocs); + + if (hlist_empty(&cookie->backing_objects)) + goto nobufs; + + ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX); + ASSERTCMP(page, !=, NULL); + + if (fscache_wait_for_deferred_lookup(cookie) < 0) + return -ERESTARTSYS; + + op = fscache_alloc_retrieval(page->mapping, NULL, NULL); + if (!op) + return -ENOMEM; + + spin_lock(&cookie->lock); + + if (hlist_empty(&cookie->backing_objects)) + goto nobufs_unlock; + object = hlist_entry(cookie->backing_objects.first, + struct fscache_object, cookie_link); + + if (fscache_submit_op(object, &op->op) < 0) + goto nobufs_unlock; + spin_unlock(&cookie->lock); + + fscache_stat(&fscache_n_alloc_ops); + + if (test_bit(FSCACHE_OP_WAITING, &op->op.flags)) { + _debug(">>> WT"); + fscache_stat(&fscache_n_alloc_op_waits); + wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING, + fscache_wait_bit, TASK_UNINTERRUPTIBLE); + _debug("<<< GO"); + } + + /* ask the cache to honour the operation */ + ret = object->cache->ops->allocate_page(op, page, gfp); + + if (ret < 0) + fscache_stat(&fscache_n_allocs_nobufs); + else + fscache_stat(&fscache_n_allocs_ok); + + fscache_put_retrieval(op); + _leave(" = %d", ret); + return ret; + +nobufs_unlock: + spin_unlock(&cookie->lock); + kfree(op); +nobufs: + fscache_stat(&fscache_n_allocs_nobufs); + _leave(" = -ENOBUFS"); + return -ENOBUFS; +} +EXPORT_SYMBOL(__fscache_alloc_page); + +/* + * release a write op reference + */ +static void fscache_release_write_op(struct fscache_operation *_op) +{ + _enter("{OP%x}", _op->debug_id); +} + +/* + * perform the background storage of a page into the cache + */ +static void fscache_write_op(struct fscache_operation *_op) +{ + struct fscache_storage *op = + container_of(_op, struct fscache_storage, op); + struct fscache_object *object = op->op.object; + struct fscache_cookie *cookie = object->cookie; + struct page *page; + unsigned n; + void *results[1]; + int ret; + + _enter("{OP%x,%d}", op->op.debug_id, atomic_read(&op->op.usage)); + + spin_lock(&cookie->lock); + spin_lock(&object->lock); + + if (!fscache_object_is_active(object)) { + spin_unlock(&object->lock); + spin_unlock(&cookie->lock); + _leave(""); + return; + } + + fscache_stat(&fscache_n_store_calls); + + /* find a page to store */ + page = NULL; + n = radix_tree_gang_lookup_tag(&cookie->stores, results, 0, 1, + FSCACHE_COOKIE_PENDING_TAG); + if (n != 1) + goto superseded; + page = results[0]; + _debug("gang %d [%lx]", n, page->index); + if (page->index > op->store_limit) + goto superseded; + + radix_tree_tag_clear(&cookie->stores, page->index, + FSCACHE_COOKIE_PENDING_TAG); + + spin_unlock(&object->lock); + spin_unlock(&cookie->lock); + + if (page) { + ret = object->cache->ops->write_page(op, page); + fscache_end_page_write(cookie, page); + page_cache_release(page); + if (ret < 0) + fscache_abort_object(object); + else + fscache_enqueue_operation(&op->op); + } + + _leave(""); + return; + +superseded: + /* this writer is going away and there aren't any more things to + * write */ + _debug("cease"); + clear_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags); + spin_unlock(&object->lock); + spin_unlock(&cookie->lock); + _leave(""); +} + +/* + * request a page be stored in the cache + * - returns: + * -ENOMEM - out of memory, nothing done + * -ENOBUFS - no backing object available in which to cache the page + * 0 - dispatched a write - it'll call end_io_func() when finished + * + * if the cookie still has a backing object at this point, that object can be + * in one of a few states with respect to storage processing: + * + * (1) negative lookup, object not yet created (FSCACHE_COOKIE_CREATING is + * set) + * + * (a) no writes yet (set FSCACHE_COOKIE_PENDING_FILL and queue deferred + * fill op) + * + * (b) writes deferred till post-creation (mark page for writing and + * return immediately) + * + * (2) negative lookup, object created, initial fill being made from netfs + * (FSCACHE_COOKIE_INITIAL_FILL is set) + * + * (a) fill point not yet reached this page (mark page for writing and + * return) + * + * (b) fill point passed this page (queue op to store this page) + * + * (3) object extant (queue op to store this page) + * + * any other state is invalid + */ +int __fscache_write_page(struct fscache_cookie *cookie, + struct page *page, + gfp_t gfp) +{ + struct fscache_storage *op; + struct fscache_object *object; + int ret; + + _enter("%p,%x,", cookie, (u32) page->flags); + + ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX); + ASSERT(PageFsCache(page)); + + fscache_stat(&fscache_n_stores); + + op = kzalloc(sizeof(*op), GFP_NOIO); + if (!op) + goto nomem; + + fscache_operation_init(&op->op, fscache_release_write_op); + fscache_operation_init_slow(&op->op, fscache_write_op); + op->op.flags = FSCACHE_OP_SLOW | (1 << FSCACHE_OP_WAITING); + + ret = radix_tree_preload(gfp & ~__GFP_HIGHMEM); + if (ret < 0) + goto nomem_free; + + ret = -ENOBUFS; + spin_lock(&cookie->lock); + + if (hlist_empty(&cookie->backing_objects)) + goto nobufs; + object = hlist_entry(cookie->backing_objects.first, + struct fscache_object, cookie_link); + if (test_bit(FSCACHE_IOERROR, &object->cache->flags)) + goto nobufs; + + /* add the page to the pending-storage radix tree on the backing + * object */ + spin_lock(&object->lock); + + _debug("store limit %llx", (unsigned long long) object->store_limit); + + ret = radix_tree_insert(&cookie->stores, page->index, page); + if (ret < 0) { + if (ret == -EEXIST) + goto already_queued; + _debug("insert failed %d", ret); + goto nobufs_unlock_obj; + } + + radix_tree_tag_set(&cookie->stores, page->index, + FSCACHE_COOKIE_PENDING_TAG); + page_cache_get(page); + + /* we only want one writer at a time, but we do need to queue new + * writers after exclusive ops */ + if (test_and_set_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags)) + goto already_pending; + + spin_unlock(&object->lock); + + op->op.debug_id = atomic_inc_return(&fscache_op_debug_id); + op->store_limit = object->store_limit; + + if (fscache_submit_op(object, &op->op) < 0) + goto submit_failed; + + spin_unlock(&cookie->lock); + radix_tree_preload_end(); + fscache_stat(&fscache_n_store_ops); + fscache_stat(&fscache_n_stores_ok); + + /* the slow work queue now carries its own ref on the object */ + fscache_put_operation(&op->op); + _leave(" = 0"); + return 0; + +already_queued: + fscache_stat(&fscache_n_stores_again); +already_pending: + spin_unlock(&object->lock); + spin_unlock(&cookie->lock); + radix_tree_preload_end(); + kfree(op); + fscache_stat(&fscache_n_stores_ok); + _leave(" = 0"); + return 0; + +submit_failed: + radix_tree_delete(&cookie->stores, page->index); + page_cache_release(page); + ret = -ENOBUFS; + goto nobufs; + +nobufs_unlock_obj: + spin_unlock(&object->lock); +nobufs: + spin_unlock(&cookie->lock); + radix_tree_preload_end(); + kfree(op); + fscache_stat(&fscache_n_stores_nobufs); + _leave(" = -ENOBUFS"); + return -ENOBUFS; + +nomem_free: + kfree(op); +nomem: + fscache_stat(&fscache_n_stores_oom); + _leave(" = -ENOMEM"); + return -ENOMEM; +} +EXPORT_SYMBOL(__fscache_write_page); + +/* + * remove a page from the cache + */ +void __fscache_uncache_page(struct fscache_cookie *cookie, struct page *page) +{ + struct fscache_object *object; + + _enter(",%p", page); + + ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX); + ASSERTCMP(page, !=, NULL); + + fscache_stat(&fscache_n_uncaches); + + /* cache withdrawal may beat us to it */ + if (!PageFsCache(page)) + goto done; + + /* get the object */ + spin_lock(&cookie->lock); + + if (hlist_empty(&cookie->backing_objects)) { + ClearPageFsCache(page); + goto done_unlock; + } + + object = hlist_entry(cookie->backing_objects.first, + struct fscache_object, cookie_link); + + /* there might now be stuff on disk we could read */ + clear_bit(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags); + + /* only invoke the cache backend if we managed to mark the page + * uncached here; this deals with synchronisation vs withdrawal */ + if (TestClearPageFsCache(page) && + object->cache->ops->uncache_page) { + /* the cache backend releases the cookie lock */ + object->cache->ops->uncache_page(object, page); + goto done; + } + +done_unlock: + spin_unlock(&cookie->lock); +done: + _leave(""); +} +EXPORT_SYMBOL(__fscache_uncache_page); + +/** + * fscache_mark_pages_cached - Mark pages as being cached + * @op: The retrieval op pages are being marked for + * @pagevec: The pages to be marked + * + * Mark a bunch of netfs pages as being cached. After this is called, + * the netfs must call fscache_uncache_page() to remove the mark. + */ +void fscache_mark_pages_cached(struct fscache_retrieval *op, + struct pagevec *pagevec) +{ + struct fscache_cookie *cookie = op->op.object->cookie; + unsigned long loop; + +#ifdef CONFIG_FSCACHE_STATS + atomic_add(pagevec->nr, &fscache_n_marks); +#endif + + for (loop = 0; loop < pagevec->nr; loop++) { + struct page *page = pagevec->pages[loop]; + + _debug("- mark %p{%lx}", page, page->index); + if (TestSetPageFsCache(page)) { + static bool once_only; + if (!once_only) { + once_only = true; + printk(KERN_WARNING "FS-Cache:" + " Cookie type %s marked page %lx" + " multiple times\n", + cookie->def->name, page->index); + } + } + } + + if (cookie->def->mark_pages_cached) + cookie->def->mark_pages_cached(cookie->netfs_data, + op->mapping, pagevec); + pagevec_reinit(pagevec); +} +EXPORT_SYMBOL(fscache_mark_pages_cached); diff --git a/include/linux/fscache.h b/include/linux/fscache.h index 245b48646ef..6d8ee466e0a 100644 --- a/include/linux/fscache.h +++ b/include/linux/fscache.h @@ -184,6 +184,24 @@ extern struct fscache_cookie *__fscache_acquire_cookie( void *); extern void __fscache_relinquish_cookie(struct fscache_cookie *, int); extern void __fscache_update_cookie(struct fscache_cookie *); +extern int __fscache_attr_changed(struct fscache_cookie *); +extern int __fscache_read_or_alloc_page(struct fscache_cookie *, + struct page *, + fscache_rw_complete_t, + void *, + gfp_t); +extern int __fscache_read_or_alloc_pages(struct fscache_cookie *, + struct address_space *, + struct list_head *, + unsigned *, + fscache_rw_complete_t, + void *, + gfp_t); +extern int __fscache_alloc_page(struct fscache_cookie *, struct page *, gfp_t); +extern int __fscache_write_page(struct fscache_cookie *, struct page *, gfp_t); +extern void __fscache_uncache_page(struct fscache_cookie *, struct page *); +extern bool __fscache_check_page_write(struct fscache_cookie *, struct page *); +extern void __fscache_wait_on_page_write(struct fscache_cookie *, struct page *); /** * fscache_register_netfs - Register a filesystem as desiring caching services @@ -361,7 +379,10 @@ void fscache_unpin_cookie(struct fscache_cookie *cookie) static inline int fscache_attr_changed(struct fscache_cookie *cookie) { - return -ENOBUFS; + if (fscache_cookie_valid(cookie)) + return __fscache_attr_changed(cookie); + else + return -ENOBUFS; } /** @@ -418,7 +439,11 @@ int fscache_read_or_alloc_page(struct fscache_cookie *cookie, void *context, gfp_t gfp) { - return -ENOBUFS; + if (fscache_cookie_valid(cookie)) + return __fscache_read_or_alloc_page(cookie, page, end_io_func, + context, gfp); + else + return -ENOBUFS; } /** @@ -464,7 +489,12 @@ int fscache_read_or_alloc_pages(struct fscache_cookie *cookie, void *context, gfp_t gfp) { - return -ENOBUFS; + if (fscache_cookie_valid(cookie)) + return __fscache_read_or_alloc_pages(cookie, mapping, pages, + nr_pages, end_io_func, + context, gfp); + else + return -ENOBUFS; } /** @@ -490,7 +520,10 @@ int fscache_alloc_page(struct fscache_cookie *cookie, struct page *page, gfp_t gfp) { - return -ENOBUFS; + if (fscache_cookie_valid(cookie)) + return __fscache_alloc_page(cookie, page, gfp); + else + return -ENOBUFS; } /** @@ -516,7 +549,10 @@ int fscache_write_page(struct fscache_cookie *cookie, struct page *page, gfp_t gfp) { - return -ENOBUFS; + if (fscache_cookie_valid(cookie)) + return __fscache_write_page(cookie, page, gfp); + else + return -ENOBUFS; } /** @@ -537,6 +573,8 @@ static inline void fscache_uncache_page(struct fscache_cookie *cookie, struct page *page) { + if (fscache_cookie_valid(cookie)) + __fscache_uncache_page(cookie, page); } /** @@ -553,6 +591,8 @@ static inline bool fscache_check_page_write(struct fscache_cookie *cookie, struct page *page) { + if (fscache_cookie_valid(cookie)) + return __fscache_check_page_write(cookie, page); return false; } @@ -571,6 +611,8 @@ static inline void fscache_wait_on_page_write(struct fscache_cookie *cookie, struct page *page) { + if (fscache_cookie_valid(cookie)) + __fscache_wait_on_page_write(cookie, page); } #endif /* _LINUX_FSCACHE_H */ -- cgit v1.2.3-70-g09d2 From 800a964787faef3509d194fa33268628c3d1daa9 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:40 +0100 Subject: CacheFiles: Export things for CacheFiles Export a number of functions for CacheFiles's use. Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Rik van Riel Acked-by: Al Viro Tested-by: Daire Byrne --- fs/super.c | 1 + security/security.c | 2 ++ 2 files changed, 3 insertions(+) (limited to 'fs') diff --git a/fs/super.c b/fs/super.c index 2ba481518ba..77cb4ec919b 100644 --- a/fs/super.c +++ b/fs/super.c @@ -287,6 +287,7 @@ int fsync_super(struct super_block *sb) __fsync_super(sb); return sync_blockdev(sb->s_bdev); } +EXPORT_SYMBOL_GPL(fsync_super); /** * generic_shutdown_super - common helper for ->kill_sb() diff --git a/security/security.c b/security/security.c index 206e53844d2..5284255c5cd 100644 --- a/security/security.c +++ b/security/security.c @@ -445,6 +445,7 @@ int security_inode_create(struct inode *dir, struct dentry *dentry, int mode) return 0; return security_ops->inode_create(dir, dentry, mode); } +EXPORT_SYMBOL_GPL(security_inode_create); int security_inode_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry) @@ -475,6 +476,7 @@ int security_inode_mkdir(struct inode *dir, struct dentry *dentry, int mode) return 0; return security_ops->inode_mkdir(dir, dentry, mode); } +EXPORT_SYMBOL_GPL(security_inode_mkdir); int security_inode_rmdir(struct inode *dir, struct dentry *dentry) { -- cgit v1.2.3-70-g09d2 From 9ae326a69004dea8af2dae4fde58de27db700a8d Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:41 +0100 Subject: CacheFiles: A cache that backs onto a mounted filesystem Add an FS-Cache cache-backend that permits a mounted filesystem to be used as a backing store for the cache. CacheFiles uses a userspace daemon to do some of the cache management - such as reaping stale nodes and culling. This is called cachefilesd and lives in /sbin. The source for the daemon can be downloaded from: http://people.redhat.com/~dhowells/cachefs/cachefilesd.c And an example configuration from: http://people.redhat.com/~dhowells/cachefs/cachefilesd.conf The filesystem and data integrity of the cache are only as good as those of the filesystem providing the backing services. Note that CacheFiles does not attempt to journal anything since the journalling interfaces of the various filesystems are very specific in nature. CacheFiles creates a misc character device - "/dev/cachefiles" - that is used to communication with the daemon. Only one thing may have this open at once, and whilst it is open, a cache is at least partially in existence. The daemon opens this and sends commands down it to control the cache. CacheFiles is currently limited to a single cache. CacheFiles attempts to maintain at least a certain percentage of free space on the filesystem, shrinking the cache by culling the objects it contains to make space if necessary - see the "Cache Culling" section. This means it can be placed on the same medium as a live set of data, and will expand to make use of spare space and automatically contract when the set of data requires more space. ============ REQUIREMENTS ============ The use of CacheFiles and its daemon requires the following features to be available in the system and in the cache filesystem: - dnotify. - extended attributes (xattrs). - openat() and friends. - bmap() support on files in the filesystem (FIBMAP ioctl). - The use of bmap() to detect a partial page at the end of the file. It is strongly recommended that the "dir_index" option is enabled on Ext3 filesystems being used as a cache. ============= CONFIGURATION ============= The cache is configured by a script in /etc/cachefilesd.conf. These commands set up cache ready for use. The following script commands are available: (*) brun % (*) bcull % (*) bstop % (*) frun % (*) fcull % (*) fstop % Configure the culling limits. Optional. See the section on culling The defaults are 7% (run), 5% (cull) and 1% (stop) respectively. The commands beginning with a 'b' are file space (block) limits, those beginning with an 'f' are file count limits. (*) dir Specify the directory containing the root of the cache. Mandatory. (*) tag Specify a tag to FS-Cache to use in distinguishing multiple caches. Optional. The default is "CacheFiles". (*) debug Specify a numeric bitmask to control debugging in the kernel module. Optional. The default is zero (all off). The following values can be OR'd into the mask to collect various information: 1 Turn on trace of function entry (_enter() macros) 2 Turn on trace of function exit (_leave() macros) 4 Turn on trace of internal debug points (_debug()) This mask can also be set through sysfs, eg: echo 5 >/sys/modules/cachefiles/parameters/debug ================== STARTING THE CACHE ================== The cache is started by running the daemon. The daemon opens the cache device, configures the cache and tells it to begin caching. At that point the cache binds to fscache and the cache becomes live. The daemon is run as follows: /sbin/cachefilesd [-d]* [-s] [-n] [-f ] The flags are: (*) -d Increase the debugging level. This can be specified multiple times and is cumulative with itself. (*) -s Send messages to stderr instead of syslog. (*) -n Don't daemonise and go into background. (*) -f Use an alternative configuration file rather than the default one. =============== THINGS TO AVOID =============== Do not mount other things within the cache as this will cause problems. The kernel module contains its own very cut-down path walking facility that ignores mountpoints, but the daemon can't avoid them. Do not create, rename or unlink files and directories in the cache whilst the cache is active, as this may cause the state to become uncertain. Renaming files in the cache might make objects appear to be other objects (the filename is part of the lookup key). Do not change or remove the extended attributes attached to cache files by the cache as this will cause the cache state management to get confused. Do not create files or directories in the cache, lest the cache get confused or serve incorrect data. Do not chmod files in the cache. The module creates things with minimal permissions to prevent random users being able to access them directly. ============= CACHE CULLING ============= The cache may need culling occasionally to make space. This involves discarding objects from the cache that have been used less recently than anything else. Culling is based on the access time of data objects. Empty directories are culled if not in use. Cache culling is done on the basis of the percentage of blocks and the percentage of files available in the underlying filesystem. There are six "limits": (*) brun (*) frun If the amount of free space and the number of available files in the cache rises above both these limits, then culling is turned off. (*) bcull (*) fcull If the amount of available space or the number of available files in the cache falls below either of these limits, then culling is started. (*) bstop (*) fstop If the amount of available space or the number of available files in the cache falls below either of these limits, then no further allocation of disk space or files is permitted until culling has raised things above these limits again. These must be configured thusly: 0 <= bstop < bcull < brun < 100 0 <= fstop < fcull < frun < 100 Note that these are percentages of available space and available files, and do _not_ appear as 100 minus the percentage displayed by the "df" program. The userspace daemon scans the cache to build up a table of cullable objects. These are then culled in least recently used order. A new scan of the cache is started as soon as space is made in the table. Objects will be skipped if their atimes have changed or if the kernel module says it is still using them. =============== CACHE STRUCTURE =============== The CacheFiles module will create two directories in the directory it was given: (*) cache/ (*) graveyard/ The active cache objects all reside in the first directory. The CacheFiles kernel module moves any retired or culled objects that it can't simply unlink to the graveyard from which the daemon will actually delete them. The daemon uses dnotify to monitor the graveyard directory, and will delete anything that appears therein. The module represents index objects as directories with the filename "I..." or "J...". Note that the "cache/" directory is itself a special index. Data objects are represented as files if they have no children, or directories if they do. Their filenames all begin "D..." or "E...". If represented as a directory, data objects will have a file in the directory called "data" that actually holds the data. Special objects are similar to data objects, except their filenames begin "S..." or "T...". If an object has children, then it will be represented as a directory. Immediately in the representative directory are a collection of directories named for hash values of the child object keys with an '@' prepended. Into this directory, if possible, will be placed the representations of the child objects: INDEX INDEX INDEX DATA FILES ========= ========== ================================= ================ cache/@4a/I03nfs/@30/Ji000000000000000--fHg8hi8400 cache/@4a/I03nfs/@30/Ji000000000000000--fHg8hi8400/@75/Es0g000w...DB1ry cache/@4a/I03nfs/@30/Ji000000000000000--fHg8hi8400/@75/Es0g000w...N22ry cache/@4a/I03nfs/@30/Ji000000000000000--fHg8hi8400/@75/Es0g000w...FP1ry If the key is so long that it exceeds NAME_MAX with the decorations added on to it, then it will be cut into pieces, the first few of which will be used to make a nest of directories, and the last one of which will be the objects inside the last directory. The names of the intermediate directories will have '+' prepended: J1223/@23/+xy...z/+kl...m/Epqr Note that keys are raw data, and not only may they exceed NAME_MAX in size, they may also contain things like '/' and NUL characters, and so they may not be suitable for turning directly into a filename. To handle this, CacheFiles will use a suitably printable filename directly and "base-64" encode ones that aren't directly suitable. The two versions of object filenames indicate the encoding: OBJECT TYPE PRINTABLE ENCODED =============== =============== =============== Index "I..." "J..." Data "D..." "E..." Special "S..." "T..." Intermediate directories are always "@" or "+" as appropriate. Each object in the cache has an extended attribute label that holds the object type ID (required to distinguish special objects) and the auxiliary data from the netfs. The latter is used to detect stale objects in the cache and update or retire them. Note that CacheFiles will erase from the cache any file it doesn't recognise or any file of an incorrect type (such as a FIFO file or a device file). ========================== SECURITY MODEL AND SELINUX ========================== CacheFiles is implemented to deal properly with the LSM security features of the Linux kernel and the SELinux facility. One of the problems that CacheFiles faces is that it is generally acting on behalf of a process, and running in that process's context, and that includes a security context that is not appropriate for accessing the cache - either because the files in the cache are inaccessible to that process, or because if the process creates a file in the cache, that file may be inaccessible to other processes. The way CacheFiles works is to temporarily change the security context (fsuid, fsgid and actor security label) that the process acts as - without changing the security context of the process when it the target of an operation performed by some other process (so signalling and suchlike still work correctly). When the CacheFiles module is asked to bind to its cache, it: (1) Finds the security label attached to the root cache directory and uses that as the security label with which it will create files. By default, this is: cachefiles_var_t (2) Finds the security label of the process which issued the bind request (presumed to be the cachefilesd daemon), which by default will be: cachefilesd_t and asks LSM to supply a security ID as which it should act given the daemon's label. By default, this will be: cachefiles_kernel_t SELinux transitions the daemon's security ID to the module's security ID based on a rule of this form in the policy. type_transition kernel_t : process ; For instance: type_transition cachefilesd_t kernel_t : process cachefiles_kernel_t; The module's security ID gives it permission to create, move and remove files and directories in the cache, to find and access directories and files in the cache, to set and access extended attributes on cache objects, and to read and write files in the cache. The daemon's security ID gives it only a very restricted set of permissions: it may scan directories, stat files and erase files and directories. It may not read or write files in the cache, and so it is precluded from accessing the data cached therein; nor is it permitted to create new files in the cache. There are policy source files available in: http://people.redhat.com/~dhowells/fscache/cachefilesd-0.8.tar.bz2 and later versions. In that tarball, see the files: cachefilesd.te cachefilesd.fc cachefilesd.if They are built and installed directly by the RPM. If a non-RPM based system is being used, then copy the above files to their own directory and run: make -f /usr/share/selinux/devel/Makefile semodule -i cachefilesd.pp You will need checkpolicy and selinux-policy-devel installed prior to the build. By default, the cache is located in /var/fscache, but if it is desirable that it should be elsewhere, than either the above policy files must be altered, or an auxiliary policy must be installed to label the alternate location of the cache. For instructions on how to add an auxiliary policy to enable the cache to be located elsewhere when SELinux is in enforcing mode, please see: /usr/share/doc/cachefilesd-*/move-cache.txt When the cachefilesd rpm is installed; alternatively, the document can be found in the sources. ================== A NOTE ON SECURITY ================== CacheFiles makes use of the split security in the task_struct. It allocates its own task_security structure, and redirects current->act_as to point to it when it acts on behalf of another process, in that process's context. The reason it does this is that it calls vfs_mkdir() and suchlike rather than bypassing security and calling inode ops directly. Therefore the VFS and LSM may deny the CacheFiles access to the cache data because under some circumstances the caching code is running in the security context of whatever process issued the original syscall on the netfs. Furthermore, should CacheFiles create a file or directory, the security parameters with that object is created (UID, GID, security label) would be derived from that process that issued the system call, thus potentially preventing other processes from accessing the cache - including CacheFiles's cache management daemon (cachefilesd). What is required is to temporarily override the security of the process that issued the system call. We can't, however, just do an in-place change of the security data as that affects the process as an object, not just as a subject. This means it may lose signals or ptrace events for example, and affects what the process looks like in /proc. So CacheFiles makes use of a logical split in the security between the objective security (task->sec) and the subjective security (task->act_as). The objective security holds the intrinsic security properties of a process and is never overridden. This is what appears in /proc, and is what is used when a process is the target of an operation by some other process (SIGKILL for example). The subjective security holds the active security properties of a process, and may be overridden. This is not seen externally, and is used whan a process acts upon another object, for example SIGKILLing another process or opening a file. LSM hooks exist that allow SELinux (or Smack or whatever) to reject a request for CacheFiles to run in a context of a specific security label, or to create files and directories with another security label. This documentation is added by the patch to: Documentation/filesystems/caching/cachefiles.txt Signed-Off-By: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Al Viro Tested-by: Daire Byrne --- Documentation/filesystems/caching/cachefiles.txt | 501 +++++++++++++ fs/Kconfig | 1 + fs/Makefile | 1 + fs/cachefiles/Kconfig | 39 + fs/cachefiles/Makefile | 18 + fs/cachefiles/bind.c | 286 ++++++++ fs/cachefiles/daemon.c | 755 +++++++++++++++++++ fs/cachefiles/interface.c | 449 ++++++++++++ fs/cachefiles/internal.h | 360 ++++++++++ fs/cachefiles/key.c | 159 ++++ fs/cachefiles/main.c | 106 +++ fs/cachefiles/namei.c | 771 ++++++++++++++++++++ fs/cachefiles/proc.c | 134 ++++ fs/cachefiles/rdwr.c | 879 +++++++++++++++++++++++ fs/cachefiles/security.c | 116 +++ fs/cachefiles/xattr.c | 291 ++++++++ 16 files changed, 4866 insertions(+) create mode 100644 Documentation/filesystems/caching/cachefiles.txt create mode 100644 fs/cachefiles/Kconfig create mode 100644 fs/cachefiles/Makefile create mode 100644 fs/cachefiles/bind.c create mode 100644 fs/cachefiles/daemon.c create mode 100644 fs/cachefiles/interface.c create mode 100644 fs/cachefiles/internal.h create mode 100644 fs/cachefiles/key.c create mode 100644 fs/cachefiles/main.c create mode 100644 fs/cachefiles/namei.c create mode 100644 fs/cachefiles/proc.c create mode 100644 fs/cachefiles/rdwr.c create mode 100644 fs/cachefiles/security.c create mode 100644 fs/cachefiles/xattr.c (limited to 'fs') diff --git a/Documentation/filesystems/caching/cachefiles.txt b/Documentation/filesystems/caching/cachefiles.txt new file mode 100644 index 00000000000..c78a49b7bba --- /dev/null +++ b/Documentation/filesystems/caching/cachefiles.txt @@ -0,0 +1,501 @@ + =============================================== + CacheFiles: CACHE ON ALREADY MOUNTED FILESYSTEM + =============================================== + +Contents: + + (*) Overview. + + (*) Requirements. + + (*) Configuration. + + (*) Starting the cache. + + (*) Things to avoid. + + (*) Cache culling. + + (*) Cache structure. + + (*) Security model and SELinux. + + (*) A note on security. + + (*) Statistical information. + + (*) Debugging. + + +======== +OVERVIEW +======== + +CacheFiles is a caching backend that's meant to use as a cache a directory on +an already mounted filesystem of a local type (such as Ext3). + +CacheFiles uses a userspace daemon to do some of the cache management - such as +reaping stale nodes and culling. This is called cachefilesd and lives in +/sbin. + +The filesystem and data integrity of the cache are only as good as those of the +filesystem providing the backing services. Note that CacheFiles does not +attempt to journal anything since the journalling interfaces of the various +filesystems are very specific in nature. + +CacheFiles creates a misc character device - "/dev/cachefiles" - that is used +to communication with the daemon. Only one thing may have this open at once, +and whilst it is open, a cache is at least partially in existence. The daemon +opens this and sends commands down it to control the cache. + +CacheFiles is currently limited to a single cache. + +CacheFiles attempts to maintain at least a certain percentage of free space on +the filesystem, shrinking the cache by culling the objects it contains to make +space if necessary - see the "Cache Culling" section. This means it can be +placed on the same medium as a live set of data, and will expand to make use of +spare space and automatically contract when the set of data requires more +space. + + +============ +REQUIREMENTS +============ + +The use of CacheFiles and its daemon requires the following features to be +available in the system and in the cache filesystem: + + - dnotify. + + - extended attributes (xattrs). + + - openat() and friends. + + - bmap() support on files in the filesystem (FIBMAP ioctl). + + - The use of bmap() to detect a partial page at the end of the file. + +It is strongly recommended that the "dir_index" option is enabled on Ext3 +filesystems being used as a cache. + + +============= +CONFIGURATION +============= + +The cache is configured by a script in /etc/cachefilesd.conf. These commands +set up cache ready for use. The following script commands are available: + + (*) brun % + (*) bcull % + (*) bstop % + (*) frun % + (*) fcull % + (*) fstop % + + Configure the culling limits. Optional. See the section on culling + The defaults are 7% (run), 5% (cull) and 1% (stop) respectively. + + The commands beginning with a 'b' are file space (block) limits, those + beginning with an 'f' are file count limits. + + (*) dir + + Specify the directory containing the root of the cache. Mandatory. + + (*) tag + + Specify a tag to FS-Cache to use in distinguishing multiple caches. + Optional. The default is "CacheFiles". + + (*) debug + + Specify a numeric bitmask to control debugging in the kernel module. + Optional. The default is zero (all off). The following values can be + OR'd into the mask to collect various information: + + 1 Turn on trace of function entry (_enter() macros) + 2 Turn on trace of function exit (_leave() macros) + 4 Turn on trace of internal debug points (_debug()) + + This mask can also be set through sysfs, eg: + + echo 5 >/sys/modules/cachefiles/parameters/debug + + +================== +STARTING THE CACHE +================== + +The cache is started by running the daemon. The daemon opens the cache device, +configures the cache and tells it to begin caching. At that point the cache +binds to fscache and the cache becomes live. + +The daemon is run as follows: + + /sbin/cachefilesd [-d]* [-s] [-n] [-f ] + +The flags are: + + (*) -d + + Increase the debugging level. This can be specified multiple times and + is cumulative with itself. + + (*) -s + + Send messages to stderr instead of syslog. + + (*) -n + + Don't daemonise and go into background. + + (*) -f + + Use an alternative configuration file rather than the default one. + + +=============== +THINGS TO AVOID +=============== + +Do not mount other things within the cache as this will cause problems. The +kernel module contains its own very cut-down path walking facility that ignores +mountpoints, but the daemon can't avoid them. + +Do not create, rename or unlink files and directories in the cache whilst the +cache is active, as this may cause the state to become uncertain. + +Renaming files in the cache might make objects appear to be other objects (the +filename is part of the lookup key). + +Do not change or remove the extended attributes attached to cache files by the +cache as this will cause the cache state management to get confused. + +Do not create files or directories in the cache, lest the cache get confused or +serve incorrect data. + +Do not chmod files in the cache. The module creates things with minimal +permissions to prevent random users being able to access them directly. + + +============= +CACHE CULLING +============= + +The cache may need culling occasionally to make space. This involves +discarding objects from the cache that have been used less recently than +anything else. Culling is based on the access time of data objects. Empty +directories are culled if not in use. + +Cache culling is done on the basis of the percentage of blocks and the +percentage of files available in the underlying filesystem. There are six +"limits": + + (*) brun + (*) frun + + If the amount of free space and the number of available files in the cache + rises above both these limits, then culling is turned off. + + (*) bcull + (*) fcull + + If the amount of available space or the number of available files in the + cache falls below either of these limits, then culling is started. + + (*) bstop + (*) fstop + + If the amount of available space or the number of available files in the + cache falls below either of these limits, then no further allocation of + disk space or files is permitted until culling has raised things above + these limits again. + +These must be configured thusly: + + 0 <= bstop < bcull < brun < 100 + 0 <= fstop < fcull < frun < 100 + +Note that these are percentages of available space and available files, and do +_not_ appear as 100 minus the percentage displayed by the "df" program. + +The userspace daemon scans the cache to build up a table of cullable objects. +These are then culled in least recently used order. A new scan of the cache is +started as soon as space is made in the table. Objects will be skipped if +their atimes have changed or if the kernel module says it is still using them. + + +=============== +CACHE STRUCTURE +=============== + +The CacheFiles module will create two directories in the directory it was +given: + + (*) cache/ + + (*) graveyard/ + +The active cache objects all reside in the first directory. The CacheFiles +kernel module moves any retired or culled objects that it can't simply unlink +to the graveyard from which the daemon will actually delete them. + +The daemon uses dnotify to monitor the graveyard directory, and will delete +anything that appears therein. + + +The module represents index objects as directories with the filename "I..." or +"J...". Note that the "cache/" directory is itself a special index. + +Data objects are represented as files if they have no children, or directories +if they do. Their filenames all begin "D..." or "E...". If represented as a +directory, data objects will have a file in the directory called "data" that +actually holds the data. + +Special objects are similar to data objects, except their filenames begin +"S..." or "T...". + + +If an object has children, then it will be represented as a directory. +Immediately in the representative directory are a collection of directories +named for hash values of the child object keys with an '@' prepended. Into +this directory, if possible, will be placed the representations of the child +objects: + + INDEX INDEX INDEX DATA FILES + ========= ========== ================================= ================ + cache/@4a/I03nfs/@30/Ji000000000000000--fHg8hi8400 + cache/@4a/I03nfs/@30/Ji000000000000000--fHg8hi8400/@75/Es0g000w...DB1ry + cache/@4a/I03nfs/@30/Ji000000000000000--fHg8hi8400/@75/Es0g000w...N22ry + cache/@4a/I03nfs/@30/Ji000000000000000--fHg8hi8400/@75/Es0g000w...FP1ry + + +If the key is so long that it exceeds NAME_MAX with the decorations added on to +it, then it will be cut into pieces, the first few of which will be used to +make a nest of directories, and the last one of which will be the objects +inside the last directory. The names of the intermediate directories will have +'+' prepended: + + J1223/@23/+xy...z/+kl...m/Epqr + + +Note that keys are raw data, and not only may they exceed NAME_MAX in size, +they may also contain things like '/' and NUL characters, and so they may not +be suitable for turning directly into a filename. + +To handle this, CacheFiles will use a suitably printable filename directly and +"base-64" encode ones that aren't directly suitable. The two versions of +object filenames indicate the encoding: + + OBJECT TYPE PRINTABLE ENCODED + =============== =============== =============== + Index "I..." "J..." + Data "D..." "E..." + Special "S..." "T..." + +Intermediate directories are always "@" or "+" as appropriate. + + +Each object in the cache has an extended attribute label that holds the object +type ID (required to distinguish special objects) and the auxiliary data from +the netfs. The latter is used to detect stale objects in the cache and update +or retire them. + + +Note that CacheFiles will erase from the cache any file it doesn't recognise or +any file of an incorrect type (such as a FIFO file or a device file). + + +========================== +SECURITY MODEL AND SELINUX +========================== + +CacheFiles is implemented to deal properly with the LSM security features of +the Linux kernel and the SELinux facility. + +One of the problems that CacheFiles faces is that it is generally acting on +behalf of a process, and running in that process's context, and that includes a +security context that is not appropriate for accessing the cache - either +because the files in the cache are inaccessible to that process, or because if +the process creates a file in the cache, that file may be inaccessible to other +processes. + +The way CacheFiles works is to temporarily change the security context (fsuid, +fsgid and actor security label) that the process acts as - without changing the +security context of the process when it the target of an operation performed by +some other process (so signalling and suchlike still work correctly). + + +When the CacheFiles module is asked to bind to its cache, it: + + (1) Finds the security label attached to the root cache directory and uses + that as the security label with which it will create files. By default, + this is: + + cachefiles_var_t + + (2) Finds the security label of the process which issued the bind request + (presumed to be the cachefilesd daemon), which by default will be: + + cachefilesd_t + + and asks LSM to supply a security ID as which it should act given the + daemon's label. By default, this will be: + + cachefiles_kernel_t + + SELinux transitions the daemon's security ID to the module's security ID + based on a rule of this form in the policy. + + type_transition kernel_t : process ; + + For instance: + + type_transition cachefilesd_t kernel_t : process cachefiles_kernel_t; + + +The module's security ID gives it permission to create, move and remove files +and directories in the cache, to find and access directories and files in the +cache, to set and access extended attributes on cache objects, and to read and +write files in the cache. + +The daemon's security ID gives it only a very restricted set of permissions: it +may scan directories, stat files and erase files and directories. It may +not read or write files in the cache, and so it is precluded from accessing the +data cached therein; nor is it permitted to create new files in the cache. + + +There are policy source files available in: + + http://people.redhat.com/~dhowells/fscache/cachefilesd-0.8.tar.bz2 + +and later versions. In that tarball, see the files: + + cachefilesd.te + cachefilesd.fc + cachefilesd.if + +They are built and installed directly by the RPM. + +If a non-RPM based system is being used, then copy the above files to their own +directory and run: + + make -f /usr/share/selinux/devel/Makefile + semodule -i cachefilesd.pp + +You will need checkpolicy and selinux-policy-devel installed prior to the +build. + + +By default, the cache is located in /var/fscache, but if it is desirable that +it should be elsewhere, than either the above policy files must be altered, or +an auxiliary policy must be installed to label the alternate location of the +cache. + +For instructions on how to add an auxiliary policy to enable the cache to be +located elsewhere when SELinux is in enforcing mode, please see: + + /usr/share/doc/cachefilesd-*/move-cache.txt + +When the cachefilesd rpm is installed; alternatively, the document can be found +in the sources. + + +================== +A NOTE ON SECURITY +================== + +CacheFiles makes use of the split security in the task_struct. It allocates +its own task_security structure, and redirects current->act_as to point to it +when it acts on behalf of another process, in that process's context. + +The reason it does this is that it calls vfs_mkdir() and suchlike rather than +bypassing security and calling inode ops directly. Therefore the VFS and LSM +may deny the CacheFiles access to the cache data because under some +circumstances the caching code is running in the security context of whatever +process issued the original syscall on the netfs. + +Furthermore, should CacheFiles create a file or directory, the security +parameters with that object is created (UID, GID, security label) would be +derived from that process that issued the system call, thus potentially +preventing other processes from accessing the cache - including CacheFiles's +cache management daemon (cachefilesd). + +What is required is to temporarily override the security of the process that +issued the system call. We can't, however, just do an in-place change of the +security data as that affects the process as an object, not just as a subject. +This means it may lose signals or ptrace events for example, and affects what +the process looks like in /proc. + +So CacheFiles makes use of a logical split in the security between the +objective security (task->sec) and the subjective security (task->act_as). The +objective security holds the intrinsic security properties of a process and is +never overridden. This is what appears in /proc, and is what is used when a +process is the target of an operation by some other process (SIGKILL for +example). + +The subjective security holds the active security properties of a process, and +may be overridden. This is not seen externally, and is used whan a process +acts upon another object, for example SIGKILLing another process or opening a +file. + +LSM hooks exist that allow SELinux (or Smack or whatever) to reject a request +for CacheFiles to run in a context of a specific security label, or to create +files and directories with another security label. + + +======================= +STATISTICAL INFORMATION +======================= + +If FS-Cache is compiled with the following option enabled: + + CONFIG_CACHEFILES_HISTOGRAM=y + +then it will gather certain statistics and display them through a proc file. + + (*) /proc/fs/cachefiles/histogram + + cat /proc/fs/cachefiles/histogram + JIFS SECS LOOKUPS MKDIRS CREATES + ===== ===== ========= ========= ========= + + This shows the breakdown of the number of times each amount of time + between 0 jiffies and HZ-1 jiffies a variety of tasks took to run. The + columns are as follows: + + COLUMN TIME MEASUREMENT + ======= ======================================================= + LOOKUPS Length of time to perform a lookup on the backing fs + MKDIRS Length of time to perform a mkdir on the backing fs + CREATES Length of time to perform a create on the backing fs + + Each row shows the number of events that took a particular range of times. + Each step is 1 jiffy in size. The JIFS column indicates the particular + jiffy range covered, and the SECS field the equivalent number of seconds. + + +========= +DEBUGGING +========= + +If CONFIG_CACHEFILES_DEBUG is enabled, the CacheFiles facility can have runtime +debugging enabled by adjusting the value in: + + /sys/module/cachefiles/parameters/debug + +This is a bitmask of debugging streams to enable: + + BIT VALUE STREAM POINT + ======= ======= =============================== ======================= + 0 1 General Function entry trace + 1 2 Function exit trace + 2 4 General + +The appropriate set of values should be OR'd together and the result written to +the control file. For example: + + echo $((1|4|8)) >/sys/module/cachefiles/parameters/debug + +will turn on all function entry debugging. diff --git a/fs/Kconfig b/fs/Kconfig index 3942df6ad04..c0022b1d587 100644 --- a/fs/Kconfig +++ b/fs/Kconfig @@ -69,6 +69,7 @@ config GENERIC_ACL menu "Caches" source "fs/fscache/Kconfig" +source "fs/cachefiles/Kconfig" endmenu diff --git a/fs/Makefile b/fs/Makefile index ff5a10d898c..055d5237b10 100644 --- a/fs/Makefile +++ b/fs/Makefile @@ -117,6 +117,7 @@ obj-$(CONFIG_AFS_FS) += afs/ obj-$(CONFIG_BEFS_FS) += befs/ obj-$(CONFIG_HOSTFS) += hostfs/ obj-$(CONFIG_HPPFS) += hppfs/ +obj-$(CONFIG_CACHEFILES) += cachefiles/ obj-$(CONFIG_DEBUG_FS) += debugfs/ obj-$(CONFIG_OCFS2_FS) += ocfs2/ obj-$(CONFIG_BTRFS_FS) += btrfs/ diff --git a/fs/cachefiles/Kconfig b/fs/cachefiles/Kconfig new file mode 100644 index 00000000000..80e9c6167f0 --- /dev/null +++ b/fs/cachefiles/Kconfig @@ -0,0 +1,39 @@ + +config CACHEFILES + tristate "Filesystem caching on files" + depends on FSCACHE && BLOCK + help + This permits use of a mounted filesystem as a cache for other + filesystems - primarily networking filesystems - thus allowing fast + local disk to enhance the speed of slower devices. + + See Documentation/filesystems/caching/cachefiles.txt for more + information. + +config CACHEFILES_DEBUG + bool "Debug CacheFiles" + depends on CACHEFILES + help + This permits debugging to be dynamically enabled in the filesystem + caching on files module. If this is set, the debugging output may be + enabled by setting bits in /sys/modules/cachefiles/parameter/debug or + by including a debugging specifier in /etc/cachefilesd.conf. + +config CACHEFILES_HISTOGRAM + bool "Gather latency information on CacheFiles" + depends on CACHEFILES && PROC_FS + help + + This option causes latency information to be gathered on CacheFiles + operation and exported through file: + + /proc/fs/cachefiles/histogram + + The generation of this histogram adds a certain amount of overhead to + execution as there are a number of points at which data is gathered, + and on a multi-CPU system these may be on cachelines that keep + bouncing between CPUs. On the other hand, the histogram may be + useful for debugging purposes. Saying 'N' here is recommended. + + See Documentation/filesystems/caching/cachefiles.txt for more + information. diff --git a/fs/cachefiles/Makefile b/fs/cachefiles/Makefile new file mode 100644 index 00000000000..32cbab0ffce --- /dev/null +++ b/fs/cachefiles/Makefile @@ -0,0 +1,18 @@ +# +# Makefile for caching in a mounted filesystem +# + +cachefiles-y := \ + bind.o \ + daemon.o \ + interface.o \ + key.o \ + main.o \ + namei.o \ + rdwr.o \ + security.o \ + xattr.o + +cachefiles-$(CONFIG_CACHEFILES_HISTOGRAM) += proc.o + +obj-$(CONFIG_CACHEFILES) := cachefiles.o diff --git a/fs/cachefiles/bind.c b/fs/cachefiles/bind.c new file mode 100644 index 00000000000..3797e0077b3 --- /dev/null +++ b/fs/cachefiles/bind.c @@ -0,0 +1,286 @@ +/* Bind and unbind a cache from the filesystem backing it + * + * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "internal.h" + +static int cachefiles_daemon_add_cache(struct cachefiles_cache *caches); + +/* + * bind a directory as a cache + */ +int cachefiles_daemon_bind(struct cachefiles_cache *cache, char *args) +{ + _enter("{%u,%u,%u,%u,%u,%u},%s", + cache->frun_percent, + cache->fcull_percent, + cache->fstop_percent, + cache->brun_percent, + cache->bcull_percent, + cache->bstop_percent, + args); + + /* start by checking things over */ + ASSERT(cache->fstop_percent >= 0 && + cache->fstop_percent < cache->fcull_percent && + cache->fcull_percent < cache->frun_percent && + cache->frun_percent < 100); + + ASSERT(cache->bstop_percent >= 0 && + cache->bstop_percent < cache->bcull_percent && + cache->bcull_percent < cache->brun_percent && + cache->brun_percent < 100); + + if (*args) { + kerror("'bind' command doesn't take an argument"); + return -EINVAL; + } + + if (!cache->rootdirname) { + kerror("No cache directory specified"); + return -EINVAL; + } + + /* don't permit already bound caches to be re-bound */ + if (test_bit(CACHEFILES_READY, &cache->flags)) { + kerror("Cache already bound"); + return -EBUSY; + } + + /* make sure we have copies of the tag and dirname strings */ + if (!cache->tag) { + /* the tag string is released by the fops->release() + * function, so we don't release it on error here */ + cache->tag = kstrdup("CacheFiles", GFP_KERNEL); + if (!cache->tag) + return -ENOMEM; + } + + /* add the cache */ + return cachefiles_daemon_add_cache(cache); +} + +/* + * add a cache + */ +static int cachefiles_daemon_add_cache(struct cachefiles_cache *cache) +{ + struct cachefiles_object *fsdef; + struct nameidata nd; + struct kstatfs stats; + struct dentry *graveyard, *cachedir, *root; + const struct cred *saved_cred; + int ret; + + _enter(""); + + /* we want to work under the module's security ID */ + ret = cachefiles_get_security_ID(cache); + if (ret < 0) + return ret; + + cachefiles_begin_secure(cache, &saved_cred); + + /* allocate the root index object */ + ret = -ENOMEM; + + fsdef = kmem_cache_alloc(cachefiles_object_jar, GFP_KERNEL); + if (!fsdef) + goto error_root_object; + + ASSERTCMP(fsdef->backer, ==, NULL); + + atomic_set(&fsdef->usage, 1); + fsdef->type = FSCACHE_COOKIE_TYPE_INDEX; + + _debug("- fsdef %p", fsdef); + + /* look up the directory at the root of the cache */ + memset(&nd, 0, sizeof(nd)); + + ret = path_lookup(cache->rootdirname, LOOKUP_DIRECTORY, &nd); + if (ret < 0) + goto error_open_root; + + cache->mnt = mntget(nd.path.mnt); + root = dget(nd.path.dentry); + path_put(&nd.path); + + /* check parameters */ + ret = -EOPNOTSUPP; + if (!root->d_inode || + !root->d_inode->i_op || + !root->d_inode->i_op->lookup || + !root->d_inode->i_op->mkdir || + !root->d_inode->i_op->setxattr || + !root->d_inode->i_op->getxattr || + !root->d_sb || + !root->d_sb->s_op || + !root->d_sb->s_op->statfs || + !root->d_sb->s_op->sync_fs) + goto error_unsupported; + + ret = -EROFS; + if (root->d_sb->s_flags & MS_RDONLY) + goto error_unsupported; + + /* determine the security of the on-disk cache as this governs + * security ID of files we create */ + ret = cachefiles_determine_cache_security(cache, root, &saved_cred); + if (ret < 0) + goto error_unsupported; + + /* get the cache size and blocksize */ + ret = vfs_statfs(root, &stats); + if (ret < 0) + goto error_unsupported; + + ret = -ERANGE; + if (stats.f_bsize <= 0) + goto error_unsupported; + + ret = -EOPNOTSUPP; + if (stats.f_bsize > PAGE_SIZE) + goto error_unsupported; + + cache->bsize = stats.f_bsize; + cache->bshift = 0; + if (stats.f_bsize < PAGE_SIZE) + cache->bshift = PAGE_SHIFT - ilog2(stats.f_bsize); + + _debug("blksize %u (shift %u)", + cache->bsize, cache->bshift); + + _debug("size %llu, avail %llu", + (unsigned long long) stats.f_blocks, + (unsigned long long) stats.f_bavail); + + /* set up caching limits */ + do_div(stats.f_files, 100); + cache->fstop = stats.f_files * cache->fstop_percent; + cache->fcull = stats.f_files * cache->fcull_percent; + cache->frun = stats.f_files * cache->frun_percent; + + _debug("limits {%llu,%llu,%llu} files", + (unsigned long long) cache->frun, + (unsigned long long) cache->fcull, + (unsigned long long) cache->fstop); + + stats.f_blocks >>= cache->bshift; + do_div(stats.f_blocks, 100); + cache->bstop = stats.f_blocks * cache->bstop_percent; + cache->bcull = stats.f_blocks * cache->bcull_percent; + cache->brun = stats.f_blocks * cache->brun_percent; + + _debug("limits {%llu,%llu,%llu} blocks", + (unsigned long long) cache->brun, + (unsigned long long) cache->bcull, + (unsigned long long) cache->bstop); + + /* get the cache directory and check its type */ + cachedir = cachefiles_get_directory(cache, root, "cache"); + if (IS_ERR(cachedir)) { + ret = PTR_ERR(cachedir); + goto error_unsupported; + } + + fsdef->dentry = cachedir; + fsdef->fscache.cookie = NULL; + + ret = cachefiles_check_object_type(fsdef); + if (ret < 0) + goto error_unsupported; + + /* get the graveyard directory */ + graveyard = cachefiles_get_directory(cache, root, "graveyard"); + if (IS_ERR(graveyard)) { + ret = PTR_ERR(graveyard); + goto error_unsupported; + } + + cache->graveyard = graveyard; + + /* publish the cache */ + fscache_init_cache(&cache->cache, + &cachefiles_cache_ops, + "%s", + fsdef->dentry->d_sb->s_id); + + fscache_object_init(&fsdef->fscache, NULL, &cache->cache); + + ret = fscache_add_cache(&cache->cache, &fsdef->fscache, cache->tag); + if (ret < 0) + goto error_add_cache; + + /* done */ + set_bit(CACHEFILES_READY, &cache->flags); + dput(root); + + printk(KERN_INFO "CacheFiles:" + " File cache on %s registered\n", + cache->cache.identifier); + + /* check how much space the cache has */ + cachefiles_has_space(cache, 0, 0); + cachefiles_end_secure(cache, saved_cred); + return 0; + +error_add_cache: + dput(cache->graveyard); + cache->graveyard = NULL; +error_unsupported: + mntput(cache->mnt); + cache->mnt = NULL; + dput(fsdef->dentry); + fsdef->dentry = NULL; + dput(root); +error_open_root: + kmem_cache_free(cachefiles_object_jar, fsdef); +error_root_object: + cachefiles_end_secure(cache, saved_cred); + kerror("Failed to register: %d", ret); + return ret; +} + +/* + * unbind a cache on fd release + */ +void cachefiles_daemon_unbind(struct cachefiles_cache *cache) +{ + _enter(""); + + if (test_bit(CACHEFILES_READY, &cache->flags)) { + printk(KERN_INFO "CacheFiles:" + " File cache on %s unregistering\n", + cache->cache.identifier); + + fscache_withdraw_cache(&cache->cache); + } + + dput(cache->graveyard); + mntput(cache->mnt); + + kfree(cache->rootdirname); + kfree(cache->secctx); + kfree(cache->tag); + + _leave(""); +} diff --git a/fs/cachefiles/daemon.c b/fs/cachefiles/daemon.c new file mode 100644 index 00000000000..4618516dd99 --- /dev/null +++ b/fs/cachefiles/daemon.c @@ -0,0 +1,755 @@ +/* Daemon interface + * + * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "internal.h" + +static int cachefiles_daemon_open(struct inode *, struct file *); +static int cachefiles_daemon_release(struct inode *, struct file *); +static ssize_t cachefiles_daemon_read(struct file *, char __user *, size_t, + loff_t *); +static ssize_t cachefiles_daemon_write(struct file *, const char __user *, + size_t, loff_t *); +static unsigned int cachefiles_daemon_poll(struct file *, + struct poll_table_struct *); +static int cachefiles_daemon_frun(struct cachefiles_cache *, char *); +static int cachefiles_daemon_fcull(struct cachefiles_cache *, char *); +static int cachefiles_daemon_fstop(struct cachefiles_cache *, char *); +static int cachefiles_daemon_brun(struct cachefiles_cache *, char *); +static int cachefiles_daemon_bcull(struct cachefiles_cache *, char *); +static int cachefiles_daemon_bstop(struct cachefiles_cache *, char *); +static int cachefiles_daemon_cull(struct cachefiles_cache *, char *); +static int cachefiles_daemon_debug(struct cachefiles_cache *, char *); +static int cachefiles_daemon_dir(struct cachefiles_cache *, char *); +static int cachefiles_daemon_inuse(struct cachefiles_cache *, char *); +static int cachefiles_daemon_secctx(struct cachefiles_cache *, char *); +static int cachefiles_daemon_tag(struct cachefiles_cache *, char *); + +static unsigned long cachefiles_open; + +const struct file_operations cachefiles_daemon_fops = { + .owner = THIS_MODULE, + .open = cachefiles_daemon_open, + .release = cachefiles_daemon_release, + .read = cachefiles_daemon_read, + .write = cachefiles_daemon_write, + .poll = cachefiles_daemon_poll, +}; + +struct cachefiles_daemon_cmd { + char name[8]; + int (*handler)(struct cachefiles_cache *cache, char *args); +}; + +static const struct cachefiles_daemon_cmd cachefiles_daemon_cmds[] = { + { "bind", cachefiles_daemon_bind }, + { "brun", cachefiles_daemon_brun }, + { "bcull", cachefiles_daemon_bcull }, + { "bstop", cachefiles_daemon_bstop }, + { "cull", cachefiles_daemon_cull }, + { "debug", cachefiles_daemon_debug }, + { "dir", cachefiles_daemon_dir }, + { "frun", cachefiles_daemon_frun }, + { "fcull", cachefiles_daemon_fcull }, + { "fstop", cachefiles_daemon_fstop }, + { "inuse", cachefiles_daemon_inuse }, + { "secctx", cachefiles_daemon_secctx }, + { "tag", cachefiles_daemon_tag }, + { "", NULL } +}; + + +/* + * do various checks + */ +static int cachefiles_daemon_open(struct inode *inode, struct file *file) +{ + struct cachefiles_cache *cache; + + _enter(""); + + /* only the superuser may do this */ + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + /* the cachefiles device may only be open once at a time */ + if (xchg(&cachefiles_open, 1) == 1) + return -EBUSY; + + /* allocate a cache record */ + cache = kzalloc(sizeof(struct cachefiles_cache), GFP_KERNEL); + if (!cache) { + cachefiles_open = 0; + return -ENOMEM; + } + + mutex_init(&cache->daemon_mutex); + cache->active_nodes = RB_ROOT; + rwlock_init(&cache->active_lock); + init_waitqueue_head(&cache->daemon_pollwq); + + /* set default caching limits + * - limit at 1% free space and/or free files + * - cull below 5% free space and/or free files + * - cease culling above 7% free space and/or free files + */ + cache->frun_percent = 7; + cache->fcull_percent = 5; + cache->fstop_percent = 1; + cache->brun_percent = 7; + cache->bcull_percent = 5; + cache->bstop_percent = 1; + + file->private_data = cache; + cache->cachefilesd = file; + return 0; +} + +/* + * release a cache + */ +static int cachefiles_daemon_release(struct inode *inode, struct file *file) +{ + struct cachefiles_cache *cache = file->private_data; + + _enter(""); + + ASSERT(cache); + + set_bit(CACHEFILES_DEAD, &cache->flags); + + cachefiles_daemon_unbind(cache); + + ASSERT(!cache->active_nodes.rb_node); + + /* clean up the control file interface */ + cache->cachefilesd = NULL; + file->private_data = NULL; + cachefiles_open = 0; + + kfree(cache); + + _leave(""); + return 0; +} + +/* + * read the cache state + */ +static ssize_t cachefiles_daemon_read(struct file *file, char __user *_buffer, + size_t buflen, loff_t *pos) +{ + struct cachefiles_cache *cache = file->private_data; + char buffer[256]; + int n; + + //_enter(",,%zu,", buflen); + + if (!test_bit(CACHEFILES_READY, &cache->flags)) + return 0; + + /* check how much space the cache has */ + cachefiles_has_space(cache, 0, 0); + + /* summarise */ + clear_bit(CACHEFILES_STATE_CHANGED, &cache->flags); + + n = snprintf(buffer, sizeof(buffer), + "cull=%c" + " frun=%llx" + " fcull=%llx" + " fstop=%llx" + " brun=%llx" + " bcull=%llx" + " bstop=%llx", + test_bit(CACHEFILES_CULLING, &cache->flags) ? '1' : '0', + (unsigned long long) cache->frun, + (unsigned long long) cache->fcull, + (unsigned long long) cache->fstop, + (unsigned long long) cache->brun, + (unsigned long long) cache->bcull, + (unsigned long long) cache->bstop + ); + + if (n > buflen) + return -EMSGSIZE; + + if (copy_to_user(_buffer, buffer, n) != 0) + return -EFAULT; + + return n; +} + +/* + * command the cache + */ +static ssize_t cachefiles_daemon_write(struct file *file, + const char __user *_data, + size_t datalen, + loff_t *pos) +{ + const struct cachefiles_daemon_cmd *cmd; + struct cachefiles_cache *cache = file->private_data; + ssize_t ret; + char *data, *args, *cp; + + //_enter(",,%zu,", datalen); + + ASSERT(cache); + + if (test_bit(CACHEFILES_DEAD, &cache->flags)) + return -EIO; + + if (datalen < 0 || datalen > PAGE_SIZE - 1) + return -EOPNOTSUPP; + + /* drag the command string into the kernel so we can parse it */ + data = kmalloc(datalen + 1, GFP_KERNEL); + if (!data) + return -ENOMEM; + + ret = -EFAULT; + if (copy_from_user(data, _data, datalen) != 0) + goto error; + + data[datalen] = '\0'; + + ret = -EINVAL; + if (memchr(data, '\0', datalen)) + goto error; + + /* strip any newline */ + cp = memchr(data, '\n', datalen); + if (cp) { + if (cp == data) + goto error; + + *cp = '\0'; + } + + /* parse the command */ + ret = -EOPNOTSUPP; + + for (args = data; *args; args++) + if (isspace(*args)) + break; + if (*args) { + if (args == data) + goto error; + *args = '\0'; + for (args++; isspace(*args); args++) + continue; + } + + /* run the appropriate command handler */ + for (cmd = cachefiles_daemon_cmds; cmd->name[0]; cmd++) + if (strcmp(cmd->name, data) == 0) + goto found_command; + +error: + kfree(data); + //_leave(" = %zd", ret); + return ret; + +found_command: + mutex_lock(&cache->daemon_mutex); + + ret = -EIO; + if (!test_bit(CACHEFILES_DEAD, &cache->flags)) + ret = cmd->handler(cache, args); + + mutex_unlock(&cache->daemon_mutex); + + if (ret == 0) + ret = datalen; + goto error; +} + +/* + * poll for culling state + * - use POLLOUT to indicate culling state + */ +static unsigned int cachefiles_daemon_poll(struct file *file, + struct poll_table_struct *poll) +{ + struct cachefiles_cache *cache = file->private_data; + unsigned int mask; + + poll_wait(file, &cache->daemon_pollwq, poll); + mask = 0; + + if (test_bit(CACHEFILES_STATE_CHANGED, &cache->flags)) + mask |= POLLIN; + + if (test_bit(CACHEFILES_CULLING, &cache->flags)) + mask |= POLLOUT; + + return mask; +} + +/* + * give a range error for cache space constraints + * - can be tail-called + */ +static int cachefiles_daemon_range_error(struct cachefiles_cache *cache, + char *args) +{ + kerror("Free space limits must be in range" + " 0%%<=stop%" + */ +static int cachefiles_daemon_frun(struct cachefiles_cache *cache, char *args) +{ + unsigned long frun; + + _enter(",%s", args); + + if (!*args) + return -EINVAL; + + frun = simple_strtoul(args, &args, 10); + if (args[0] != '%' || args[1] != '\0') + return -EINVAL; + + if (frun <= cache->fcull_percent || frun >= 100) + return cachefiles_daemon_range_error(cache, args); + + cache->frun_percent = frun; + return 0; +} + +/* + * set the percentage of files at which to start culling + * - command: "fcull %" + */ +static int cachefiles_daemon_fcull(struct cachefiles_cache *cache, char *args) +{ + unsigned long fcull; + + _enter(",%s", args); + + if (!*args) + return -EINVAL; + + fcull = simple_strtoul(args, &args, 10); + if (args[0] != '%' || args[1] != '\0') + return -EINVAL; + + if (fcull <= cache->fstop_percent || fcull >= cache->frun_percent) + return cachefiles_daemon_range_error(cache, args); + + cache->fcull_percent = fcull; + return 0; +} + +/* + * set the percentage of files at which to stop allocating + * - command: "fstop %" + */ +static int cachefiles_daemon_fstop(struct cachefiles_cache *cache, char *args) +{ + unsigned long fstop; + + _enter(",%s", args); + + if (!*args) + return -EINVAL; + + fstop = simple_strtoul(args, &args, 10); + if (args[0] != '%' || args[1] != '\0') + return -EINVAL; + + if (fstop < 0 || fstop >= cache->fcull_percent) + return cachefiles_daemon_range_error(cache, args); + + cache->fstop_percent = fstop; + return 0; +} + +/* + * set the percentage of blocks at which to stop culling + * - command: "brun %" + */ +static int cachefiles_daemon_brun(struct cachefiles_cache *cache, char *args) +{ + unsigned long brun; + + _enter(",%s", args); + + if (!*args) + return -EINVAL; + + brun = simple_strtoul(args, &args, 10); + if (args[0] != '%' || args[1] != '\0') + return -EINVAL; + + if (brun <= cache->bcull_percent || brun >= 100) + return cachefiles_daemon_range_error(cache, args); + + cache->brun_percent = brun; + return 0; +} + +/* + * set the percentage of blocks at which to start culling + * - command: "bcull %" + */ +static int cachefiles_daemon_bcull(struct cachefiles_cache *cache, char *args) +{ + unsigned long bcull; + + _enter(",%s", args); + + if (!*args) + return -EINVAL; + + bcull = simple_strtoul(args, &args, 10); + if (args[0] != '%' || args[1] != '\0') + return -EINVAL; + + if (bcull <= cache->bstop_percent || bcull >= cache->brun_percent) + return cachefiles_daemon_range_error(cache, args); + + cache->bcull_percent = bcull; + return 0; +} + +/* + * set the percentage of blocks at which to stop allocating + * - command: "bstop %" + */ +static int cachefiles_daemon_bstop(struct cachefiles_cache *cache, char *args) +{ + unsigned long bstop; + + _enter(",%s", args); + + if (!*args) + return -EINVAL; + + bstop = simple_strtoul(args, &args, 10); + if (args[0] != '%' || args[1] != '\0') + return -EINVAL; + + if (bstop < 0 || bstop >= cache->bcull_percent) + return cachefiles_daemon_range_error(cache, args); + + cache->bstop_percent = bstop; + return 0; +} + +/* + * set the cache directory + * - command: "dir " + */ +static int cachefiles_daemon_dir(struct cachefiles_cache *cache, char *args) +{ + char *dir; + + _enter(",%s", args); + + if (!*args) { + kerror("Empty directory specified"); + return -EINVAL; + } + + if (cache->rootdirname) { + kerror("Second cache directory specified"); + return -EEXIST; + } + + dir = kstrdup(args, GFP_KERNEL); + if (!dir) + return -ENOMEM; + + cache->rootdirname = dir; + return 0; +} + +/* + * set the cache security context + * - command: "secctx " + */ +static int cachefiles_daemon_secctx(struct cachefiles_cache *cache, char *args) +{ + char *secctx; + + _enter(",%s", args); + + if (!*args) { + kerror("Empty security context specified"); + return -EINVAL; + } + + if (cache->secctx) { + kerror("Second security context specified"); + return -EINVAL; + } + + secctx = kstrdup(args, GFP_KERNEL); + if (!secctx) + return -ENOMEM; + + cache->secctx = secctx; + return 0; +} + +/* + * set the cache tag + * - command: "tag " + */ +static int cachefiles_daemon_tag(struct cachefiles_cache *cache, char *args) +{ + char *tag; + + _enter(",%s", args); + + if (!*args) { + kerror("Empty tag specified"); + return -EINVAL; + } + + if (cache->tag) + return -EEXIST; + + tag = kstrdup(args, GFP_KERNEL); + if (!tag) + return -ENOMEM; + + cache->tag = tag; + return 0; +} + +/* + * request a node in the cache be culled from the current working directory + * - command: "cull " + */ +static int cachefiles_daemon_cull(struct cachefiles_cache *cache, char *args) +{ + struct fs_struct *fs; + struct dentry *dir; + const struct cred *saved_cred; + int ret; + + _enter(",%s", args); + + if (strchr(args, '/')) + goto inval; + + if (!test_bit(CACHEFILES_READY, &cache->flags)) { + kerror("cull applied to unready cache"); + return -EIO; + } + + if (test_bit(CACHEFILES_DEAD, &cache->flags)) { + kerror("cull applied to dead cache"); + return -EIO; + } + + /* extract the directory dentry from the cwd */ + fs = current->fs; + read_lock(&fs->lock); + dir = dget(fs->pwd.dentry); + read_unlock(&fs->lock); + + if (!S_ISDIR(dir->d_inode->i_mode)) + goto notdir; + + cachefiles_begin_secure(cache, &saved_cred); + ret = cachefiles_cull(cache, dir, args); + cachefiles_end_secure(cache, saved_cred); + + dput(dir); + _leave(" = %d", ret); + return ret; + +notdir: + dput(dir); + kerror("cull command requires dirfd to be a directory"); + return -ENOTDIR; + +inval: + kerror("cull command requires dirfd and filename"); + return -EINVAL; +} + +/* + * set debugging mode + * - command: "debug " + */ +static int cachefiles_daemon_debug(struct cachefiles_cache *cache, char *args) +{ + unsigned long mask; + + _enter(",%s", args); + + mask = simple_strtoul(args, &args, 0); + if (args[0] != '\0') + goto inval; + + cachefiles_debug = mask; + _leave(" = 0"); + return 0; + +inval: + kerror("debug command requires mask"); + return -EINVAL; +} + +/* + * find out whether an object in the current working directory is in use or not + * - command: "inuse " + */ +static int cachefiles_daemon_inuse(struct cachefiles_cache *cache, char *args) +{ + struct fs_struct *fs; + struct dentry *dir; + const struct cred *saved_cred; + int ret; + + //_enter(",%s", args); + + if (strchr(args, '/')) + goto inval; + + if (!test_bit(CACHEFILES_READY, &cache->flags)) { + kerror("inuse applied to unready cache"); + return -EIO; + } + + if (test_bit(CACHEFILES_DEAD, &cache->flags)) { + kerror("inuse applied to dead cache"); + return -EIO; + } + + /* extract the directory dentry from the cwd */ + fs = current->fs; + read_lock(&fs->lock); + dir = dget(fs->pwd.dentry); + read_unlock(&fs->lock); + + if (!S_ISDIR(dir->d_inode->i_mode)) + goto notdir; + + cachefiles_begin_secure(cache, &saved_cred); + ret = cachefiles_check_in_use(cache, dir, args); + cachefiles_end_secure(cache, saved_cred); + + dput(dir); + //_leave(" = %d", ret); + return ret; + +notdir: + dput(dir); + kerror("inuse command requires dirfd to be a directory"); + return -ENOTDIR; + +inval: + kerror("inuse command requires dirfd and filename"); + return -EINVAL; +} + +/* + * see if we have space for a number of pages and/or a number of files in the + * cache + */ +int cachefiles_has_space(struct cachefiles_cache *cache, + unsigned fnr, unsigned bnr) +{ + struct kstatfs stats; + int ret; + + //_enter("{%llu,%llu,%llu,%llu,%llu,%llu},%u,%u", + // (unsigned long long) cache->frun, + // (unsigned long long) cache->fcull, + // (unsigned long long) cache->fstop, + // (unsigned long long) cache->brun, + // (unsigned long long) cache->bcull, + // (unsigned long long) cache->bstop, + // fnr, bnr); + + /* find out how many pages of blockdev are available */ + memset(&stats, 0, sizeof(stats)); + + ret = vfs_statfs(cache->mnt->mnt_root, &stats); + if (ret < 0) { + if (ret == -EIO) + cachefiles_io_error(cache, "statfs failed"); + _leave(" = %d", ret); + return ret; + } + + stats.f_bavail >>= cache->bshift; + + //_debug("avail %llu,%llu", + // (unsigned long long) stats.f_ffree, + // (unsigned long long) stats.f_bavail); + + /* see if there is sufficient space */ + if (stats.f_ffree > fnr) + stats.f_ffree -= fnr; + else + stats.f_ffree = 0; + + if (stats.f_bavail > bnr) + stats.f_bavail -= bnr; + else + stats.f_bavail = 0; + + ret = -ENOBUFS; + if (stats.f_ffree < cache->fstop || + stats.f_bavail < cache->bstop) + goto begin_cull; + + ret = 0; + if (stats.f_ffree < cache->fcull || + stats.f_bavail < cache->bcull) + goto begin_cull; + + if (test_bit(CACHEFILES_CULLING, &cache->flags) && + stats.f_ffree >= cache->frun && + stats.f_bavail >= cache->brun && + test_and_clear_bit(CACHEFILES_CULLING, &cache->flags) + ) { + _debug("cease culling"); + cachefiles_state_changed(cache); + } + + //_leave(" = 0"); + return 0; + +begin_cull: + if (!test_and_set_bit(CACHEFILES_CULLING, &cache->flags)) { + _debug("### CULL CACHE ###"); + cachefiles_state_changed(cache); + } + + _leave(" = %d", ret); + return ret; +} diff --git a/fs/cachefiles/interface.c b/fs/cachefiles/interface.c new file mode 100644 index 00000000000..1e962348d11 --- /dev/null +++ b/fs/cachefiles/interface.c @@ -0,0 +1,449 @@ +/* FS-Cache interface to CacheFiles + * + * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#include +#include +#include "internal.h" + +#define list_to_page(head) (list_entry((head)->prev, struct page, lru)) + +struct cachefiles_lookup_data { + struct cachefiles_xattr *auxdata; /* auxiliary data */ + char *key; /* key path */ +}; + +static int cachefiles_attr_changed(struct fscache_object *_object); + +/* + * allocate an object record for a cookie lookup and prepare the lookup data + */ +static struct fscache_object *cachefiles_alloc_object( + struct fscache_cache *_cache, + struct fscache_cookie *cookie) +{ + struct cachefiles_lookup_data *lookup_data; + struct cachefiles_object *object; + struct cachefiles_cache *cache; + struct cachefiles_xattr *auxdata; + unsigned keylen, auxlen; + void *buffer; + char *key; + + cache = container_of(_cache, struct cachefiles_cache, cache); + + _enter("{%s},%p,", cache->cache.identifier, cookie); + + lookup_data = kmalloc(sizeof(*lookup_data), GFP_KERNEL); + if (!lookup_data) + goto nomem_lookup_data; + + /* create a new object record and a temporary leaf image */ + object = kmem_cache_alloc(cachefiles_object_jar, GFP_KERNEL); + if (!object) + goto nomem_object; + + ASSERTCMP(object->backer, ==, NULL); + + BUG_ON(test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags)); + atomic_set(&object->usage, 1); + + fscache_object_init(&object->fscache, cookie, &cache->cache); + + object->type = cookie->def->type; + + /* get hold of the raw key + * - stick the length on the front and leave space on the back for the + * encoder + */ + buffer = kmalloc((2 + 512) + 3, GFP_KERNEL); + if (!buffer) + goto nomem_buffer; + + keylen = cookie->def->get_key(cookie->netfs_data, buffer + 2, 512); + ASSERTCMP(keylen, <, 512); + + *(uint16_t *)buffer = keylen; + ((char *)buffer)[keylen + 2] = 0; + ((char *)buffer)[keylen + 3] = 0; + ((char *)buffer)[keylen + 4] = 0; + + /* turn the raw key into something that can work with as a filename */ + key = cachefiles_cook_key(buffer, keylen + 2, object->type); + if (!key) + goto nomem_key; + + /* get hold of the auxiliary data and prepend the object type */ + auxdata = buffer; + auxlen = 0; + if (cookie->def->get_aux) { + auxlen = cookie->def->get_aux(cookie->netfs_data, + auxdata->data, 511); + ASSERTCMP(auxlen, <, 511); + } + + auxdata->len = auxlen + 1; + auxdata->type = cookie->def->type; + + lookup_data->auxdata = auxdata; + lookup_data->key = key; + object->lookup_data = lookup_data; + + _leave(" = %p [%p]", &object->fscache, lookup_data); + return &object->fscache; + +nomem_key: + kfree(buffer); +nomem_buffer: + BUG_ON(test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags)); + kmem_cache_free(cachefiles_object_jar, object); + fscache_object_destroyed(&cache->cache); +nomem_object: + kfree(lookup_data); +nomem_lookup_data: + _leave(" = -ENOMEM"); + return ERR_PTR(-ENOMEM); +} + +/* + * attempt to look up the nominated node in this cache + */ +static void cachefiles_lookup_object(struct fscache_object *_object) +{ + struct cachefiles_lookup_data *lookup_data; + struct cachefiles_object *parent, *object; + struct cachefiles_cache *cache; + const struct cred *saved_cred; + int ret; + + _enter("{OBJ%x}", _object->debug_id); + + cache = container_of(_object->cache, struct cachefiles_cache, cache); + parent = container_of(_object->parent, + struct cachefiles_object, fscache); + object = container_of(_object, struct cachefiles_object, fscache); + lookup_data = object->lookup_data; + + ASSERTCMP(lookup_data, !=, NULL); + + /* look up the key, creating any missing bits */ + cachefiles_begin_secure(cache, &saved_cred); + ret = cachefiles_walk_to_object(parent, object, + lookup_data->key, + lookup_data->auxdata); + cachefiles_end_secure(cache, saved_cred); + + /* polish off by setting the attributes of non-index files */ + if (ret == 0 && + object->fscache.cookie->def->type != FSCACHE_COOKIE_TYPE_INDEX) + cachefiles_attr_changed(&object->fscache); + + if (ret < 0) { + printk(KERN_WARNING "CacheFiles: Lookup failed error %d\n", + ret); + fscache_object_lookup_error(&object->fscache); + } + + _leave(" [%d]", ret); +} + +/* + * indication of lookup completion + */ +static void cachefiles_lookup_complete(struct fscache_object *_object) +{ + struct cachefiles_object *object; + + object = container_of(_object, struct cachefiles_object, fscache); + + _enter("{OBJ%x,%p}", object->fscache.debug_id, object->lookup_data); + + if (object->lookup_data) { + kfree(object->lookup_data->key); + kfree(object->lookup_data->auxdata); + kfree(object->lookup_data); + object->lookup_data = NULL; + } +} + +/* + * increment the usage count on an inode object (may fail if unmounting) + */ +static +struct fscache_object *cachefiles_grab_object(struct fscache_object *_object) +{ + struct cachefiles_object *object = + container_of(_object, struct cachefiles_object, fscache); + + _enter("{OBJ%x,%d}", _object->debug_id, atomic_read(&object->usage)); + +#ifdef CACHEFILES_DEBUG_SLAB + ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000); +#endif + + atomic_inc(&object->usage); + return &object->fscache; +} + +/* + * update the auxilliary data for an object object on disk + */ +static void cachefiles_update_object(struct fscache_object *_object) +{ + struct cachefiles_object *object; + struct cachefiles_xattr *auxdata; + struct cachefiles_cache *cache; + struct fscache_cookie *cookie; + const struct cred *saved_cred; + unsigned auxlen; + + _enter("{OBJ%x}", _object->debug_id); + + object = container_of(_object, struct cachefiles_object, fscache); + cache = container_of(object->fscache.cache, struct cachefiles_cache, + cache); + cookie = object->fscache.cookie; + + if (!cookie->def->get_aux) { + _leave(" [no aux]"); + return; + } + + auxdata = kmalloc(2 + 512 + 3, GFP_KERNEL); + if (!auxdata) { + _leave(" [nomem]"); + return; + } + + auxlen = cookie->def->get_aux(cookie->netfs_data, auxdata->data, 511); + ASSERTCMP(auxlen, <, 511); + + auxdata->len = auxlen + 1; + auxdata->type = cookie->def->type; + + cachefiles_begin_secure(cache, &saved_cred); + cachefiles_update_object_xattr(object, auxdata); + cachefiles_end_secure(cache, saved_cred); + kfree(auxdata); + _leave(""); +} + +/* + * discard the resources pinned by an object and effect retirement if + * requested + */ +static void cachefiles_drop_object(struct fscache_object *_object) +{ + struct cachefiles_object *object; + struct cachefiles_cache *cache; + const struct cred *saved_cred; + + ASSERT(_object); + + object = container_of(_object, struct cachefiles_object, fscache); + + _enter("{OBJ%x,%d}", + object->fscache.debug_id, atomic_read(&object->usage)); + + cache = container_of(object->fscache.cache, + struct cachefiles_cache, cache); + +#ifdef CACHEFILES_DEBUG_SLAB + ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000); +#endif + + /* delete retired objects */ + if (object->fscache.state == FSCACHE_OBJECT_RECYCLING && + _object != cache->cache.fsdef + ) { + _debug("- retire object OBJ%x", object->fscache.debug_id); + cachefiles_begin_secure(cache, &saved_cred); + cachefiles_delete_object(cache, object); + cachefiles_end_secure(cache, saved_cred); + } + + /* close the filesystem stuff attached to the object */ + if (object->backer != object->dentry) + dput(object->backer); + object->backer = NULL; + + /* note that the object is now inactive */ + if (test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags)) { + write_lock(&cache->active_lock); + if (!test_and_clear_bit(CACHEFILES_OBJECT_ACTIVE, + &object->flags)) + BUG(); + rb_erase(&object->active_node, &cache->active_nodes); + wake_up_bit(&object->flags, CACHEFILES_OBJECT_ACTIVE); + write_unlock(&cache->active_lock); + } + + dput(object->dentry); + object->dentry = NULL; + + _leave(""); +} + +/* + * dispose of a reference to an object + */ +static void cachefiles_put_object(struct fscache_object *_object) +{ + struct cachefiles_object *object; + struct fscache_cache *cache; + + ASSERT(_object); + + object = container_of(_object, struct cachefiles_object, fscache); + + _enter("{OBJ%x,%d}", + object->fscache.debug_id, atomic_read(&object->usage)); + +#ifdef CACHEFILES_DEBUG_SLAB + ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000); +#endif + + ASSERTIFCMP(object->fscache.parent, + object->fscache.parent->n_children, >, 0); + + if (atomic_dec_and_test(&object->usage)) { + _debug("- kill object OBJ%x", object->fscache.debug_id); + + ASSERT(!test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags)); + ASSERTCMP(object->fscache.parent, ==, NULL); + ASSERTCMP(object->backer, ==, NULL); + ASSERTCMP(object->dentry, ==, NULL); + ASSERTCMP(object->fscache.n_ops, ==, 0); + ASSERTCMP(object->fscache.n_children, ==, 0); + + if (object->lookup_data) { + kfree(object->lookup_data->key); + kfree(object->lookup_data->auxdata); + kfree(object->lookup_data); + object->lookup_data = NULL; + } + + cache = object->fscache.cache; + kmem_cache_free(cachefiles_object_jar, object); + fscache_object_destroyed(cache); + } + + _leave(""); +} + +/* + * sync a cache + */ +static void cachefiles_sync_cache(struct fscache_cache *_cache) +{ + struct cachefiles_cache *cache; + const struct cred *saved_cred; + int ret; + + _enter("%p", _cache); + + cache = container_of(_cache, struct cachefiles_cache, cache); + + /* make sure all pages pinned by operations on behalf of the netfs are + * written to disc */ + cachefiles_begin_secure(cache, &saved_cred); + ret = fsync_super(cache->mnt->mnt_sb); + cachefiles_end_secure(cache, saved_cred); + + if (ret == -EIO) + cachefiles_io_error(cache, + "Attempt to sync backing fs superblock" + " returned error %d", + ret); +} + +/* + * notification the attributes on an object have changed + * - called with reads/writes excluded by FS-Cache + */ +static int cachefiles_attr_changed(struct fscache_object *_object) +{ + struct cachefiles_object *object; + struct cachefiles_cache *cache; + const struct cred *saved_cred; + struct iattr newattrs; + uint64_t ni_size; + loff_t oi_size; + int ret; + + _object->cookie->def->get_attr(_object->cookie->netfs_data, &ni_size); + + _enter("{OBJ%x},[%llu]", + _object->debug_id, (unsigned long long) ni_size); + + object = container_of(_object, struct cachefiles_object, fscache); + cache = container_of(object->fscache.cache, + struct cachefiles_cache, cache); + + if (ni_size == object->i_size) + return 0; + + if (!object->backer) + return -ENOBUFS; + + ASSERT(S_ISREG(object->backer->d_inode->i_mode)); + + fscache_set_store_limit(&object->fscache, ni_size); + + oi_size = i_size_read(object->backer->d_inode); + if (oi_size == ni_size) + return 0; + + newattrs.ia_size = ni_size; + newattrs.ia_valid = ATTR_SIZE; + + cachefiles_begin_secure(cache, &saved_cred); + mutex_lock(&object->backer->d_inode->i_mutex); + ret = notify_change(object->backer, &newattrs); + mutex_unlock(&object->backer->d_inode->i_mutex); + cachefiles_end_secure(cache, saved_cred); + + if (ret == -EIO) { + fscache_set_store_limit(&object->fscache, 0); + cachefiles_io_error_obj(object, "Size set failed"); + ret = -ENOBUFS; + } + + _leave(" = %d", ret); + return ret; +} + +/* + * dissociate a cache from all the pages it was backing + */ +static void cachefiles_dissociate_pages(struct fscache_cache *cache) +{ + _enter(""); +} + +const struct fscache_cache_ops cachefiles_cache_ops = { + .name = "cachefiles", + .alloc_object = cachefiles_alloc_object, + .lookup_object = cachefiles_lookup_object, + .lookup_complete = cachefiles_lookup_complete, + .grab_object = cachefiles_grab_object, + .update_object = cachefiles_update_object, + .drop_object = cachefiles_drop_object, + .put_object = cachefiles_put_object, + .sync_cache = cachefiles_sync_cache, + .attr_changed = cachefiles_attr_changed, + .read_or_alloc_page = cachefiles_read_or_alloc_page, + .read_or_alloc_pages = cachefiles_read_or_alloc_pages, + .allocate_page = cachefiles_allocate_page, + .allocate_pages = cachefiles_allocate_pages, + .write_page = cachefiles_write_page, + .uncache_page = cachefiles_uncache_page, + .dissociate_pages = cachefiles_dissociate_pages, +}; diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h new file mode 100644 index 00000000000..19218e1463d --- /dev/null +++ b/fs/cachefiles/internal.h @@ -0,0 +1,360 @@ +/* General netfs cache on cache files internal defs + * + * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#include +#include +#include +#include +#include + +struct cachefiles_cache; +struct cachefiles_object; + +extern unsigned cachefiles_debug; +#define CACHEFILES_DEBUG_KENTER 1 +#define CACHEFILES_DEBUG_KLEAVE 2 +#define CACHEFILES_DEBUG_KDEBUG 4 + +/* + * node records + */ +struct cachefiles_object { + struct fscache_object fscache; /* fscache handle */ + struct cachefiles_lookup_data *lookup_data; /* cached lookup data */ + struct dentry *dentry; /* the file/dir representing this object */ + struct dentry *backer; /* backing file */ + loff_t i_size; /* object size */ + unsigned long flags; +#define CACHEFILES_OBJECT_ACTIVE 0 /* T if marked active */ + atomic_t usage; /* object usage count */ + uint8_t type; /* object type */ + uint8_t new; /* T if object new */ + spinlock_t work_lock; + struct rb_node active_node; /* link in active tree (dentry is key) */ +}; + +extern struct kmem_cache *cachefiles_object_jar; + +/* + * Cache files cache definition + */ +struct cachefiles_cache { + struct fscache_cache cache; /* FS-Cache record */ + struct vfsmount *mnt; /* mountpoint holding the cache */ + struct dentry *graveyard; /* directory into which dead objects go */ + struct file *cachefilesd; /* manager daemon handle */ + const struct cred *cache_cred; /* security override for accessing cache */ + struct mutex daemon_mutex; /* command serialisation mutex */ + wait_queue_head_t daemon_pollwq; /* poll waitqueue for daemon */ + struct rb_root active_nodes; /* active nodes (can't be culled) */ + rwlock_t active_lock; /* lock for active_nodes */ + atomic_t gravecounter; /* graveyard uniquifier */ + unsigned frun_percent; /* when to stop culling (% files) */ + unsigned fcull_percent; /* when to start culling (% files) */ + unsigned fstop_percent; /* when to stop allocating (% files) */ + unsigned brun_percent; /* when to stop culling (% blocks) */ + unsigned bcull_percent; /* when to start culling (% blocks) */ + unsigned bstop_percent; /* when to stop allocating (% blocks) */ + unsigned bsize; /* cache's block size */ + unsigned bshift; /* min(ilog2(PAGE_SIZE / bsize), 0) */ + uint64_t frun; /* when to stop culling */ + uint64_t fcull; /* when to start culling */ + uint64_t fstop; /* when to stop allocating */ + sector_t brun; /* when to stop culling */ + sector_t bcull; /* when to start culling */ + sector_t bstop; /* when to stop allocating */ + unsigned long flags; +#define CACHEFILES_READY 0 /* T if cache prepared */ +#define CACHEFILES_DEAD 1 /* T if cache dead */ +#define CACHEFILES_CULLING 2 /* T if cull engaged */ +#define CACHEFILES_STATE_CHANGED 3 /* T if state changed (poll trigger) */ + char *rootdirname; /* name of cache root directory */ + char *secctx; /* LSM security context */ + char *tag; /* cache binding tag */ +}; + +/* + * backing file read tracking + */ +struct cachefiles_one_read { + wait_queue_t monitor; /* link into monitored waitqueue */ + struct page *back_page; /* backing file page we're waiting for */ + struct page *netfs_page; /* netfs page we're going to fill */ + struct fscache_retrieval *op; /* retrieval op covering this */ + struct list_head op_link; /* link in op's todo list */ +}; + +/* + * backing file write tracking + */ +struct cachefiles_one_write { + struct page *netfs_page; /* netfs page to copy */ + struct cachefiles_object *object; + struct list_head obj_link; /* link in object's lists */ + fscache_rw_complete_t end_io_func; + void *context; +}; + +/* + * auxiliary data xattr buffer + */ +struct cachefiles_xattr { + uint16_t len; + uint8_t type; + uint8_t data[]; +}; + +/* + * note change of state for daemon + */ +static inline void cachefiles_state_changed(struct cachefiles_cache *cache) +{ + set_bit(CACHEFILES_STATE_CHANGED, &cache->flags); + wake_up_all(&cache->daemon_pollwq); +} + +/* + * cf-bind.c + */ +extern int cachefiles_daemon_bind(struct cachefiles_cache *cache, char *args); +extern void cachefiles_daemon_unbind(struct cachefiles_cache *cache); + +/* + * cf-daemon.c + */ +extern const struct file_operations cachefiles_daemon_fops; + +extern int cachefiles_has_space(struct cachefiles_cache *cache, + unsigned fnr, unsigned bnr); + +/* + * cf-interface.c + */ +extern const struct fscache_cache_ops cachefiles_cache_ops; + +/* + * cf-key.c + */ +extern char *cachefiles_cook_key(const u8 *raw, int keylen, uint8_t type); + +/* + * cf-namei.c + */ +extern int cachefiles_delete_object(struct cachefiles_cache *cache, + struct cachefiles_object *object); +extern int cachefiles_walk_to_object(struct cachefiles_object *parent, + struct cachefiles_object *object, + const char *key, + struct cachefiles_xattr *auxdata); +extern struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache, + struct dentry *dir, + const char *name); + +extern int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir, + char *filename); + +extern int cachefiles_check_in_use(struct cachefiles_cache *cache, + struct dentry *dir, char *filename); + +/* + * cf-proc.c + */ +#ifdef CONFIG_CACHEFILES_HISTOGRAM +extern atomic_t cachefiles_lookup_histogram[HZ]; +extern atomic_t cachefiles_mkdir_histogram[HZ]; +extern atomic_t cachefiles_create_histogram[HZ]; + +extern int __init cachefiles_proc_init(void); +extern void cachefiles_proc_cleanup(void); +static inline +void cachefiles_hist(atomic_t histogram[], unsigned long start_jif) +{ + unsigned long jif = jiffies - start_jif; + if (jif >= HZ) + jif = HZ - 1; + atomic_inc(&histogram[jif]); +} + +#else +#define cachefiles_proc_init() (0) +#define cachefiles_proc_cleanup() do {} while (0) +#define cachefiles_hist(hist, start_jif) do {} while (0) +#endif + +/* + * cf-rdwr.c + */ +extern int cachefiles_read_or_alloc_page(struct fscache_retrieval *, + struct page *, gfp_t); +extern int cachefiles_read_or_alloc_pages(struct fscache_retrieval *, + struct list_head *, unsigned *, + gfp_t); +extern int cachefiles_allocate_page(struct fscache_retrieval *, struct page *, + gfp_t); +extern int cachefiles_allocate_pages(struct fscache_retrieval *, + struct list_head *, unsigned *, gfp_t); +extern int cachefiles_write_page(struct fscache_storage *, struct page *); +extern void cachefiles_uncache_page(struct fscache_object *, struct page *); + +/* + * cf-security.c + */ +extern int cachefiles_get_security_ID(struct cachefiles_cache *cache); +extern int cachefiles_determine_cache_security(struct cachefiles_cache *cache, + struct dentry *root, + const struct cred **_saved_cred); + +static inline void cachefiles_begin_secure(struct cachefiles_cache *cache, + const struct cred **_saved_cred) +{ + *_saved_cred = override_creds(cache->cache_cred); +} + +static inline void cachefiles_end_secure(struct cachefiles_cache *cache, + const struct cred *saved_cred) +{ + revert_creds(saved_cred); +} + +/* + * cf-xattr.c + */ +extern int cachefiles_check_object_type(struct cachefiles_object *object); +extern int cachefiles_set_object_xattr(struct cachefiles_object *object, + struct cachefiles_xattr *auxdata); +extern int cachefiles_update_object_xattr(struct cachefiles_object *object, + struct cachefiles_xattr *auxdata); +extern int cachefiles_check_object_xattr(struct cachefiles_object *object, + struct cachefiles_xattr *auxdata); +extern int cachefiles_remove_object_xattr(struct cachefiles_cache *cache, + struct dentry *dentry); + + +/* + * error handling + */ +#define kerror(FMT, ...) printk(KERN_ERR "CacheFiles: "FMT"\n", ##__VA_ARGS__) + +#define cachefiles_io_error(___cache, FMT, ...) \ +do { \ + kerror("I/O Error: " FMT, ##__VA_ARGS__); \ + fscache_io_error(&(___cache)->cache); \ + set_bit(CACHEFILES_DEAD, &(___cache)->flags); \ +} while (0) + +#define cachefiles_io_error_obj(object, FMT, ...) \ +do { \ + struct cachefiles_cache *___cache; \ + \ + ___cache = container_of((object)->fscache.cache, \ + struct cachefiles_cache, cache); \ + cachefiles_io_error(___cache, FMT, ##__VA_ARGS__); \ +} while (0) + + +/* + * debug tracing + */ +#define dbgprintk(FMT, ...) \ + printk(KERN_DEBUG "[%-6.6s] "FMT"\n", current->comm, ##__VA_ARGS__) + +/* make sure we maintain the format strings, even when debugging is disabled */ +static inline void _dbprintk(const char *fmt, ...) + __attribute__((format(printf, 1, 2))); +static inline void _dbprintk(const char *fmt, ...) +{ +} + +#define kenter(FMT, ...) dbgprintk("==> %s("FMT")", __func__, ##__VA_ARGS__) +#define kleave(FMT, ...) dbgprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__) +#define kdebug(FMT, ...) dbgprintk(FMT, ##__VA_ARGS__) + + +#if defined(__KDEBUG) +#define _enter(FMT, ...) kenter(FMT, ##__VA_ARGS__) +#define _leave(FMT, ...) kleave(FMT, ##__VA_ARGS__) +#define _debug(FMT, ...) kdebug(FMT, ##__VA_ARGS__) + +#elif defined(CONFIG_CACHEFILES_DEBUG) +#define _enter(FMT, ...) \ +do { \ + if (cachefiles_debug & CACHEFILES_DEBUG_KENTER) \ + kenter(FMT, ##__VA_ARGS__); \ +} while (0) + +#define _leave(FMT, ...) \ +do { \ + if (cachefiles_debug & CACHEFILES_DEBUG_KLEAVE) \ + kleave(FMT, ##__VA_ARGS__); \ +} while (0) + +#define _debug(FMT, ...) \ +do { \ + if (cachefiles_debug & CACHEFILES_DEBUG_KDEBUG) \ + kdebug(FMT, ##__VA_ARGS__); \ +} while (0) + +#else +#define _enter(FMT, ...) _dbprintk("==> %s("FMT")", __func__, ##__VA_ARGS__) +#define _leave(FMT, ...) _dbprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__) +#define _debug(FMT, ...) _dbprintk(FMT, ##__VA_ARGS__) +#endif + +#if 1 /* defined(__KDEBUGALL) */ + +#define ASSERT(X) \ +do { \ + if (unlikely(!(X))) { \ + printk(KERN_ERR "\n"); \ + printk(KERN_ERR "CacheFiles: Assertion failed\n"); \ + BUG(); \ + } \ +} while (0) + +#define ASSERTCMP(X, OP, Y) \ +do { \ + if (unlikely(!((X) OP (Y)))) { \ + printk(KERN_ERR "\n"); \ + printk(KERN_ERR "CacheFiles: Assertion failed\n"); \ + printk(KERN_ERR "%lx " #OP " %lx is false\n", \ + (unsigned long)(X), (unsigned long)(Y)); \ + BUG(); \ + } \ +} while (0) + +#define ASSERTIF(C, X) \ +do { \ + if (unlikely((C) && !(X))) { \ + printk(KERN_ERR "\n"); \ + printk(KERN_ERR "CacheFiles: Assertion failed\n"); \ + BUG(); \ + } \ +} while (0) + +#define ASSERTIFCMP(C, X, OP, Y) \ +do { \ + if (unlikely((C) && !((X) OP (Y)))) { \ + printk(KERN_ERR "\n"); \ + printk(KERN_ERR "CacheFiles: Assertion failed\n"); \ + printk(KERN_ERR "%lx " #OP " %lx is false\n", \ + (unsigned long)(X), (unsigned long)(Y)); \ + BUG(); \ + } \ +} while (0) + +#else + +#define ASSERT(X) do {} while (0) +#define ASSERTCMP(X, OP, Y) do {} while (0) +#define ASSERTIF(C, X) do {} while (0) +#define ASSERTIFCMP(C, X, OP, Y) do {} while (0) + +#endif diff --git a/fs/cachefiles/key.c b/fs/cachefiles/key.c new file mode 100644 index 00000000000..81b8b2b3a67 --- /dev/null +++ b/fs/cachefiles/key.c @@ -0,0 +1,159 @@ +/* Key to pathname encoder + * + * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#include +#include "internal.h" + +static const char cachefiles_charmap[64] = + "0123456789" /* 0 - 9 */ + "abcdefghijklmnopqrstuvwxyz" /* 10 - 35 */ + "ABCDEFGHIJKLMNOPQRSTUVWXYZ" /* 36 - 61 */ + "_-" /* 62 - 63 */ + ; + +static const char cachefiles_filecharmap[256] = { + /* we skip space and tab and control chars */ + [33 ... 46] = 1, /* '!' -> '.' */ + /* we skip '/' as it's significant to pathwalk */ + [48 ... 127] = 1, /* '0' -> '~' */ +}; + +/* + * turn the raw key into something cooked + * - the raw key should include the length in the two bytes at the front + * - the key may be up to 514 bytes in length (including the length word) + * - "base64" encode the strange keys, mapping 3 bytes of raw to four of + * cooked + * - need to cut the cooked key into 252 char lengths (189 raw bytes) + */ +char *cachefiles_cook_key(const u8 *raw, int keylen, uint8_t type) +{ + unsigned char csum, ch; + unsigned int acc; + char *key; + int loop, len, max, seg, mark, print; + + _enter(",%d", keylen); + + BUG_ON(keylen < 2 || keylen > 514); + + csum = raw[0] + raw[1]; + print = 1; + for (loop = 2; loop < keylen; loop++) { + ch = raw[loop]; + csum += ch; + print &= cachefiles_filecharmap[ch]; + } + + if (print) { + /* if the path is usable ASCII, then we render it directly */ + max = keylen - 2; + max += 2; /* two base64'd length chars on the front */ + max += 5; /* @checksum/M */ + max += 3 * 2; /* maximum number of segment dividers (".../M") + * is ((514 + 251) / 252) = 3 + */ + max += 1; /* NUL on end */ + } else { + /* calculate the maximum length of the cooked key */ + keylen = (keylen + 2) / 3; + + max = keylen * 4; + max += 5; /* @checksum/M */ + max += 3 * 2; /* maximum number of segment dividers (".../M") + * is ((514 + 188) / 189) = 3 + */ + max += 1; /* NUL on end */ + } + + max += 1; /* 2nd NUL on end */ + + _debug("max: %d", max); + + key = kmalloc(max, GFP_KERNEL); + if (!key) + return NULL; + + len = 0; + + /* build the cooked key */ + sprintf(key, "@%02x%c+", (unsigned) csum, 0); + len = 5; + mark = len - 1; + + if (print) { + acc = *(uint16_t *) raw; + raw += 2; + + key[len + 1] = cachefiles_charmap[acc & 63]; + acc >>= 6; + key[len] = cachefiles_charmap[acc & 63]; + len += 2; + + seg = 250; + for (loop = keylen; loop > 0; loop--) { + if (seg <= 0) { + key[len++] = '\0'; + mark = len; + key[len++] = '+'; + seg = 252; + } + + key[len++] = *raw++; + ASSERT(len < max); + } + + switch (type) { + case FSCACHE_COOKIE_TYPE_INDEX: type = 'I'; break; + case FSCACHE_COOKIE_TYPE_DATAFILE: type = 'D'; break; + default: type = 'S'; break; + } + } else { + seg = 252; + for (loop = keylen; loop > 0; loop--) { + if (seg <= 0) { + key[len++] = '\0'; + mark = len; + key[len++] = '+'; + seg = 252; + } + + acc = *raw++; + acc |= *raw++ << 8; + acc |= *raw++ << 16; + + _debug("acc: %06x", acc); + + key[len++] = cachefiles_charmap[acc & 63]; + acc >>= 6; + key[len++] = cachefiles_charmap[acc & 63]; + acc >>= 6; + key[len++] = cachefiles_charmap[acc & 63]; + acc >>= 6; + key[len++] = cachefiles_charmap[acc & 63]; + + ASSERT(len < max); + } + + switch (type) { + case FSCACHE_COOKIE_TYPE_INDEX: type = 'J'; break; + case FSCACHE_COOKIE_TYPE_DATAFILE: type = 'E'; break; + default: type = 'T'; break; + } + } + + key[mark] = type; + key[len++] = 0; + key[len] = 0; + + _leave(" = %p %d", key, len); + return key; +} diff --git a/fs/cachefiles/main.c b/fs/cachefiles/main.c new file mode 100644 index 00000000000..4bfa8cf43bf --- /dev/null +++ b/fs/cachefiles/main.c @@ -0,0 +1,106 @@ +/* Network filesystem caching backend to use cache files on a premounted + * filesystem + * + * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "internal.h" + +unsigned cachefiles_debug; +module_param_named(debug, cachefiles_debug, uint, S_IWUSR | S_IRUGO); +MODULE_PARM_DESC(cachefiles_debug, "CacheFiles debugging mask"); + +MODULE_DESCRIPTION("Mounted-filesystem based cache"); +MODULE_AUTHOR("Red Hat, Inc."); +MODULE_LICENSE("GPL"); + +struct kmem_cache *cachefiles_object_jar; + +static struct miscdevice cachefiles_dev = { + .minor = MISC_DYNAMIC_MINOR, + .name = "cachefiles", + .fops = &cachefiles_daemon_fops, +}; + +static void cachefiles_object_init_once(void *_object) +{ + struct cachefiles_object *object = _object; + + memset(object, 0, sizeof(*object)); + spin_lock_init(&object->work_lock); +} + +/* + * initialise the fs caching module + */ +static int __init cachefiles_init(void) +{ + int ret; + + ret = misc_register(&cachefiles_dev); + if (ret < 0) + goto error_dev; + + /* create an object jar */ + ret = -ENOMEM; + cachefiles_object_jar = + kmem_cache_create("cachefiles_object_jar", + sizeof(struct cachefiles_object), + 0, + SLAB_HWCACHE_ALIGN, + cachefiles_object_init_once); + if (!cachefiles_object_jar) { + printk(KERN_NOTICE + "CacheFiles: Failed to allocate an object jar\n"); + goto error_object_jar; + } + + ret = cachefiles_proc_init(); + if (ret < 0) + goto error_proc; + + printk(KERN_INFO "CacheFiles: Loaded\n"); + return 0; + +error_proc: + kmem_cache_destroy(cachefiles_object_jar); +error_object_jar: + misc_deregister(&cachefiles_dev); +error_dev: + kerror("failed to register: %d", ret); + return ret; +} + +fs_initcall(cachefiles_init); + +/* + * clean up on module removal + */ +static void __exit cachefiles_exit(void) +{ + printk(KERN_INFO "CacheFiles: Unloading\n"); + + cachefiles_proc_cleanup(); + kmem_cache_destroy(cachefiles_object_jar); + misc_deregister(&cachefiles_dev); +} + +module_exit(cachefiles_exit); diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c new file mode 100644 index 00000000000..4ce818ae39e --- /dev/null +++ b/fs/cachefiles/namei.c @@ -0,0 +1,771 @@ +/* CacheFiles path walking and related routines + * + * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "internal.h" + +static int cachefiles_wait_bit(void *flags) +{ + schedule(); + return 0; +} + +/* + * record the fact that an object is now active + */ +static void cachefiles_mark_object_active(struct cachefiles_cache *cache, + struct cachefiles_object *object) +{ + struct cachefiles_object *xobject; + struct rb_node **_p, *_parent = NULL; + struct dentry *dentry; + + _enter(",%p", object); + +try_again: + write_lock(&cache->active_lock); + + if (test_and_set_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags)) + BUG(); + + dentry = object->dentry; + _p = &cache->active_nodes.rb_node; + while (*_p) { + _parent = *_p; + xobject = rb_entry(_parent, + struct cachefiles_object, active_node); + + ASSERT(xobject != object); + + if (xobject->dentry > dentry) + _p = &(*_p)->rb_left; + else if (xobject->dentry < dentry) + _p = &(*_p)->rb_right; + else + goto wait_for_old_object; + } + + rb_link_node(&object->active_node, _parent, _p); + rb_insert_color(&object->active_node, &cache->active_nodes); + + write_unlock(&cache->active_lock); + _leave(""); + return; + + /* an old object from a previous incarnation is hogging the slot - we + * need to wait for it to be destroyed */ +wait_for_old_object: + if (xobject->fscache.state < FSCACHE_OBJECT_DYING) { + printk(KERN_ERR "\n"); + printk(KERN_ERR "CacheFiles: Error:" + " Unexpected object collision\n"); + printk(KERN_ERR "xobject: OBJ%x\n", + xobject->fscache.debug_id); + printk(KERN_ERR "xobjstate=%s\n", + fscache_object_states[xobject->fscache.state]); + printk(KERN_ERR "xobjflags=%lx\n", xobject->fscache.flags); + printk(KERN_ERR "xobjevent=%lx [%lx]\n", + xobject->fscache.events, xobject->fscache.event_mask); + printk(KERN_ERR "xops=%u inp=%u exc=%u\n", + xobject->fscache.n_ops, xobject->fscache.n_in_progress, + xobject->fscache.n_exclusive); + printk(KERN_ERR "xcookie=%p [pr=%p nd=%p fl=%lx]\n", + xobject->fscache.cookie, + xobject->fscache.cookie->parent, + xobject->fscache.cookie->netfs_data, + xobject->fscache.cookie->flags); + printk(KERN_ERR "xparent=%p\n", + xobject->fscache.parent); + printk(KERN_ERR "object: OBJ%x\n", + object->fscache.debug_id); + printk(KERN_ERR "cookie=%p [pr=%p nd=%p fl=%lx]\n", + object->fscache.cookie, + object->fscache.cookie->parent, + object->fscache.cookie->netfs_data, + object->fscache.cookie->flags); + printk(KERN_ERR "parent=%p\n", + object->fscache.parent); + BUG(); + } + atomic_inc(&xobject->usage); + write_unlock(&cache->active_lock); + + _debug(">>> wait"); + wait_on_bit(&xobject->flags, CACHEFILES_OBJECT_ACTIVE, + cachefiles_wait_bit, TASK_UNINTERRUPTIBLE); + _debug("<<< waited"); + + cache->cache.ops->put_object(&xobject->fscache); + goto try_again; +} + +/* + * delete an object representation from the cache + * - file backed objects are unlinked + * - directory backed objects are stuffed into the graveyard for userspace to + * delete + * - unlocks the directory mutex + */ +static int cachefiles_bury_object(struct cachefiles_cache *cache, + struct dentry *dir, + struct dentry *rep) +{ + struct dentry *grave, *trap; + char nbuffer[8 + 8 + 1]; + int ret; + + _enter(",'%*.*s','%*.*s'", + dir->d_name.len, dir->d_name.len, dir->d_name.name, + rep->d_name.len, rep->d_name.len, rep->d_name.name); + + /* non-directories can just be unlinked */ + if (!S_ISDIR(rep->d_inode->i_mode)) { + _debug("unlink stale object"); + ret = vfs_unlink(dir->d_inode, rep); + + mutex_unlock(&dir->d_inode->i_mutex); + + if (ret == -EIO) + cachefiles_io_error(cache, "Unlink failed"); + + _leave(" = %d", ret); + return ret; + } + + /* directories have to be moved to the graveyard */ + _debug("move stale object to graveyard"); + mutex_unlock(&dir->d_inode->i_mutex); + +try_again: + /* first step is to make up a grave dentry in the graveyard */ + sprintf(nbuffer, "%08x%08x", + (uint32_t) get_seconds(), + (uint32_t) atomic_inc_return(&cache->gravecounter)); + + /* do the multiway lock magic */ + trap = lock_rename(cache->graveyard, dir); + + /* do some checks before getting the grave dentry */ + if (rep->d_parent != dir) { + /* the entry was probably culled when we dropped the parent dir + * lock */ + unlock_rename(cache->graveyard, dir); + _leave(" = 0 [culled?]"); + return 0; + } + + if (!S_ISDIR(cache->graveyard->d_inode->i_mode)) { + unlock_rename(cache->graveyard, dir); + cachefiles_io_error(cache, "Graveyard no longer a directory"); + return -EIO; + } + + if (trap == rep) { + unlock_rename(cache->graveyard, dir); + cachefiles_io_error(cache, "May not make directory loop"); + return -EIO; + } + + if (d_mountpoint(rep)) { + unlock_rename(cache->graveyard, dir); + cachefiles_io_error(cache, "Mountpoint in cache"); + return -EIO; + } + + grave = lookup_one_len(nbuffer, cache->graveyard, strlen(nbuffer)); + if (IS_ERR(grave)) { + unlock_rename(cache->graveyard, dir); + + if (PTR_ERR(grave) == -ENOMEM) { + _leave(" = -ENOMEM"); + return -ENOMEM; + } + + cachefiles_io_error(cache, "Lookup error %ld", + PTR_ERR(grave)); + return -EIO; + } + + if (grave->d_inode) { + unlock_rename(cache->graveyard, dir); + dput(grave); + grave = NULL; + cond_resched(); + goto try_again; + } + + if (d_mountpoint(grave)) { + unlock_rename(cache->graveyard, dir); + dput(grave); + cachefiles_io_error(cache, "Mountpoint in graveyard"); + return -EIO; + } + + /* target should not be an ancestor of source */ + if (trap == grave) { + unlock_rename(cache->graveyard, dir); + dput(grave); + cachefiles_io_error(cache, "May not make directory loop"); + return -EIO; + } + + /* attempt the rename */ + ret = vfs_rename(dir->d_inode, rep, cache->graveyard->d_inode, grave); + if (ret != 0 && ret != -ENOMEM) + cachefiles_io_error(cache, "Rename failed with error %d", ret); + + unlock_rename(cache->graveyard, dir); + dput(grave); + _leave(" = 0"); + return 0; +} + +/* + * delete an object representation from the cache + */ +int cachefiles_delete_object(struct cachefiles_cache *cache, + struct cachefiles_object *object) +{ + struct dentry *dir; + int ret; + + _enter(",{%p}", object->dentry); + + ASSERT(object->dentry); + ASSERT(object->dentry->d_inode); + ASSERT(object->dentry->d_parent); + + dir = dget_parent(object->dentry); + + mutex_lock(&dir->d_inode->i_mutex); + ret = cachefiles_bury_object(cache, dir, object->dentry); + + dput(dir); + _leave(" = %d", ret); + return ret; +} + +/* + * walk from the parent object to the child object through the backing + * filesystem, creating directories as we go + */ +int cachefiles_walk_to_object(struct cachefiles_object *parent, + struct cachefiles_object *object, + const char *key, + struct cachefiles_xattr *auxdata) +{ + struct cachefiles_cache *cache; + struct dentry *dir, *next = NULL; + unsigned long start; + const char *name; + int ret, nlen; + + _enter("{%p},,%s,", parent->dentry, key); + + cache = container_of(parent->fscache.cache, + struct cachefiles_cache, cache); + + ASSERT(parent->dentry); + ASSERT(parent->dentry->d_inode); + + if (!(S_ISDIR(parent->dentry->d_inode->i_mode))) { + // TODO: convert file to dir + _leave("looking up in none directory"); + return -ENOBUFS; + } + + dir = dget(parent->dentry); + +advance: + /* attempt to transit the first directory component */ + name = key; + nlen = strlen(key); + + /* key ends in a double NUL */ + key = key + nlen + 1; + if (!*key) + key = NULL; + +lookup_again: + /* search the current directory for the element name */ + _debug("lookup '%s'", name); + + mutex_lock(&dir->d_inode->i_mutex); + + start = jiffies; + next = lookup_one_len(name, dir, nlen); + cachefiles_hist(cachefiles_lookup_histogram, start); + if (IS_ERR(next)) + goto lookup_error; + + _debug("next -> %p %s", next, next->d_inode ? "positive" : "negative"); + + if (!key) + object->new = !next->d_inode; + + /* if this element of the path doesn't exist, then the lookup phase + * failed, and we can release any readers in the certain knowledge that + * there's nothing for them to actually read */ + if (!next->d_inode) + fscache_object_lookup_negative(&object->fscache); + + /* we need to create the object if it's negative */ + if (key || object->type == FSCACHE_COOKIE_TYPE_INDEX) { + /* index objects and intervening tree levels must be subdirs */ + if (!next->d_inode) { + ret = cachefiles_has_space(cache, 1, 0); + if (ret < 0) + goto create_error; + + start = jiffies; + ret = vfs_mkdir(dir->d_inode, next, 0); + cachefiles_hist(cachefiles_mkdir_histogram, start); + if (ret < 0) + goto create_error; + + ASSERT(next->d_inode); + + _debug("mkdir -> %p{%p{ino=%lu}}", + next, next->d_inode, next->d_inode->i_ino); + + } else if (!S_ISDIR(next->d_inode->i_mode)) { + kerror("inode %lu is not a directory", + next->d_inode->i_ino); + ret = -ENOBUFS; + goto error; + } + + } else { + /* non-index objects start out life as files */ + if (!next->d_inode) { + ret = cachefiles_has_space(cache, 1, 0); + if (ret < 0) + goto create_error; + + start = jiffies; + ret = vfs_create(dir->d_inode, next, S_IFREG, NULL); + cachefiles_hist(cachefiles_create_histogram, start); + if (ret < 0) + goto create_error; + + ASSERT(next->d_inode); + + _debug("create -> %p{%p{ino=%lu}}", + next, next->d_inode, next->d_inode->i_ino); + + } else if (!S_ISDIR(next->d_inode->i_mode) && + !S_ISREG(next->d_inode->i_mode) + ) { + kerror("inode %lu is not a file or directory", + next->d_inode->i_ino); + ret = -ENOBUFS; + goto error; + } + } + + /* process the next component */ + if (key) { + _debug("advance"); + mutex_unlock(&dir->d_inode->i_mutex); + dput(dir); + dir = next; + next = NULL; + goto advance; + } + + /* we've found the object we were looking for */ + object->dentry = next; + + /* if we've found that the terminal object exists, then we need to + * check its attributes and delete it if it's out of date */ + if (!object->new) { + _debug("validate '%*.*s'", + next->d_name.len, next->d_name.len, next->d_name.name); + + ret = cachefiles_check_object_xattr(object, auxdata); + if (ret == -ESTALE) { + /* delete the object (the deleter drops the directory + * mutex) */ + object->dentry = NULL; + + ret = cachefiles_bury_object(cache, dir, next); + dput(next); + next = NULL; + + if (ret < 0) + goto delete_error; + + _debug("redo lookup"); + goto lookup_again; + } + } + + /* note that we're now using this object */ + cachefiles_mark_object_active(cache, object); + + mutex_unlock(&dir->d_inode->i_mutex); + dput(dir); + dir = NULL; + + _debug("=== OBTAINED_OBJECT ==="); + + if (object->new) { + /* attach data to a newly constructed terminal object */ + ret = cachefiles_set_object_xattr(object, auxdata); + if (ret < 0) + goto check_error; + } else { + /* always update the atime on an object we've just looked up + * (this is used to keep track of culling, and atimes are only + * updated by read, write and readdir but not lookup or + * open) */ + touch_atime(cache->mnt, next); + } + + /* open a file interface onto a data file */ + if (object->type != FSCACHE_COOKIE_TYPE_INDEX) { + if (S_ISREG(object->dentry->d_inode->i_mode)) { + const struct address_space_operations *aops; + + ret = -EPERM; + aops = object->dentry->d_inode->i_mapping->a_ops; + if (!aops->bmap) + goto check_error; + + object->backer = object->dentry; + } else { + BUG(); // TODO: open file in data-class subdir + } + } + + object->new = 0; + fscache_obtained_object(&object->fscache); + + _leave(" = 0 [%lu]", object->dentry->d_inode->i_ino); + return 0; + +create_error: + _debug("create error %d", ret); + if (ret == -EIO) + cachefiles_io_error(cache, "Create/mkdir failed"); + goto error; + +check_error: + _debug("check error %d", ret); + write_lock(&cache->active_lock); + rb_erase(&object->active_node, &cache->active_nodes); + clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags); + wake_up_bit(&object->flags, CACHEFILES_OBJECT_ACTIVE); + write_unlock(&cache->active_lock); + + dput(object->dentry); + object->dentry = NULL; + goto error_out; + +delete_error: + _debug("delete error %d", ret); + goto error_out2; + +lookup_error: + _debug("lookup error %ld", PTR_ERR(next)); + ret = PTR_ERR(next); + if (ret == -EIO) + cachefiles_io_error(cache, "Lookup failed"); + next = NULL; +error: + mutex_unlock(&dir->d_inode->i_mutex); + dput(next); +error_out2: + dput(dir); +error_out: + if (ret == -ENOSPC) + ret = -ENOBUFS; + + _leave(" = error %d", -ret); + return ret; +} + +/* + * get a subdirectory + */ +struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache, + struct dentry *dir, + const char *dirname) +{ + struct dentry *subdir; + unsigned long start; + int ret; + + _enter(",,%s", dirname); + + /* search the current directory for the element name */ + mutex_lock(&dir->d_inode->i_mutex); + + start = jiffies; + subdir = lookup_one_len(dirname, dir, strlen(dirname)); + cachefiles_hist(cachefiles_lookup_histogram, start); + if (IS_ERR(subdir)) { + if (PTR_ERR(subdir) == -ENOMEM) + goto nomem_d_alloc; + goto lookup_error; + } + + _debug("subdir -> %p %s", + subdir, subdir->d_inode ? "positive" : "negative"); + + /* we need to create the subdir if it doesn't exist yet */ + if (!subdir->d_inode) { + ret = cachefiles_has_space(cache, 1, 0); + if (ret < 0) + goto mkdir_error; + + _debug("attempt mkdir"); + + ret = vfs_mkdir(dir->d_inode, subdir, 0700); + if (ret < 0) + goto mkdir_error; + + ASSERT(subdir->d_inode); + + _debug("mkdir -> %p{%p{ino=%lu}}", + subdir, + subdir->d_inode, + subdir->d_inode->i_ino); + } + + mutex_unlock(&dir->d_inode->i_mutex); + + /* we need to make sure the subdir is a directory */ + ASSERT(subdir->d_inode); + + if (!S_ISDIR(subdir->d_inode->i_mode)) { + kerror("%s is not a directory", dirname); + ret = -EIO; + goto check_error; + } + + ret = -EPERM; + if (!subdir->d_inode->i_op || + !subdir->d_inode->i_op->setxattr || + !subdir->d_inode->i_op->getxattr || + !subdir->d_inode->i_op->lookup || + !subdir->d_inode->i_op->mkdir || + !subdir->d_inode->i_op->create || + !subdir->d_inode->i_op->rename || + !subdir->d_inode->i_op->rmdir || + !subdir->d_inode->i_op->unlink) + goto check_error; + + _leave(" = [%lu]", subdir->d_inode->i_ino); + return subdir; + +check_error: + dput(subdir); + _leave(" = %d [check]", ret); + return ERR_PTR(ret); + +mkdir_error: + mutex_unlock(&dir->d_inode->i_mutex); + dput(subdir); + kerror("mkdir %s failed with error %d", dirname, ret); + return ERR_PTR(ret); + +lookup_error: + mutex_unlock(&dir->d_inode->i_mutex); + ret = PTR_ERR(subdir); + kerror("Lookup %s failed with error %d", dirname, ret); + return ERR_PTR(ret); + +nomem_d_alloc: + mutex_unlock(&dir->d_inode->i_mutex); + _leave(" = -ENOMEM"); + return ERR_PTR(-ENOMEM); +} + +/* + * find out if an object is in use or not + * - if finds object and it's not in use: + * - returns a pointer to the object and a reference on it + * - returns with the directory locked + */ +static struct dentry *cachefiles_check_active(struct cachefiles_cache *cache, + struct dentry *dir, + char *filename) +{ + struct cachefiles_object *object; + struct rb_node *_n; + struct dentry *victim; + unsigned long start; + int ret; + + //_enter(",%*.*s/,%s", + // dir->d_name.len, dir->d_name.len, dir->d_name.name, filename); + + /* look up the victim */ + mutex_lock_nested(&dir->d_inode->i_mutex, 1); + + start = jiffies; + victim = lookup_one_len(filename, dir, strlen(filename)); + cachefiles_hist(cachefiles_lookup_histogram, start); + if (IS_ERR(victim)) + goto lookup_error; + + //_debug("victim -> %p %s", + // victim, victim->d_inode ? "positive" : "negative"); + + /* if the object is no longer there then we probably retired the object + * at the netfs's request whilst the cull was in progress + */ + if (!victim->d_inode) { + mutex_unlock(&dir->d_inode->i_mutex); + dput(victim); + _leave(" = -ENOENT [absent]"); + return ERR_PTR(-ENOENT); + } + + /* check to see if we're using this object */ + read_lock(&cache->active_lock); + + _n = cache->active_nodes.rb_node; + + while (_n) { + object = rb_entry(_n, struct cachefiles_object, active_node); + + if (object->dentry > victim) + _n = _n->rb_left; + else if (object->dentry < victim) + _n = _n->rb_right; + else + goto object_in_use; + } + + read_unlock(&cache->active_lock); + + //_leave(" = %p", victim); + return victim; + +object_in_use: + read_unlock(&cache->active_lock); + mutex_unlock(&dir->d_inode->i_mutex); + dput(victim); + //_leave(" = -EBUSY [in use]"); + return ERR_PTR(-EBUSY); + +lookup_error: + mutex_unlock(&dir->d_inode->i_mutex); + ret = PTR_ERR(victim); + if (ret == -ENOENT) { + /* file or dir now absent - probably retired by netfs */ + _leave(" = -ESTALE [absent]"); + return ERR_PTR(-ESTALE); + } + + if (ret == -EIO) { + cachefiles_io_error(cache, "Lookup failed"); + } else if (ret != -ENOMEM) { + kerror("Internal error: %d", ret); + ret = -EIO; + } + + _leave(" = %d", ret); + return ERR_PTR(ret); +} + +/* + * cull an object if it's not in use + * - called only by cache manager daemon + */ +int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir, + char *filename) +{ + struct dentry *victim; + int ret; + + _enter(",%*.*s/,%s", + dir->d_name.len, dir->d_name.len, dir->d_name.name, filename); + + victim = cachefiles_check_active(cache, dir, filename); + if (IS_ERR(victim)) + return PTR_ERR(victim); + + _debug("victim -> %p %s", + victim, victim->d_inode ? "positive" : "negative"); + + /* okay... the victim is not being used so we can cull it + * - start by marking it as stale + */ + _debug("victim is cullable"); + + ret = cachefiles_remove_object_xattr(cache, victim); + if (ret < 0) + goto error_unlock; + + /* actually remove the victim (drops the dir mutex) */ + _debug("bury"); + + ret = cachefiles_bury_object(cache, dir, victim); + if (ret < 0) + goto error; + + dput(victim); + _leave(" = 0"); + return 0; + +error_unlock: + mutex_unlock(&dir->d_inode->i_mutex); +error: + dput(victim); + if (ret == -ENOENT) { + /* file or dir now absent - probably retired by netfs */ + _leave(" = -ESTALE [absent]"); + return -ESTALE; + } + + if (ret != -ENOMEM) { + kerror("Internal error: %d", ret); + ret = -EIO; + } + + _leave(" = %d", ret); + return ret; +} + +/* + * find out if an object is in use or not + * - called only by cache manager daemon + * - returns -EBUSY or 0 to indicate whether an object is in use or not + */ +int cachefiles_check_in_use(struct cachefiles_cache *cache, struct dentry *dir, + char *filename) +{ + struct dentry *victim; + + //_enter(",%*.*s/,%s", + // dir->d_name.len, dir->d_name.len, dir->d_name.name, filename); + + victim = cachefiles_check_active(cache, dir, filename); + if (IS_ERR(victim)) + return PTR_ERR(victim); + + mutex_unlock(&dir->d_inode->i_mutex); + dput(victim); + //_leave(" = 0"); + return 0; +} diff --git a/fs/cachefiles/proc.c b/fs/cachefiles/proc.c new file mode 100644 index 00000000000..eccd3394119 --- /dev/null +++ b/fs/cachefiles/proc.c @@ -0,0 +1,134 @@ +/* CacheFiles statistics + * + * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#include +#include +#include +#include "internal.h" + +atomic_t cachefiles_lookup_histogram[HZ]; +atomic_t cachefiles_mkdir_histogram[HZ]; +atomic_t cachefiles_create_histogram[HZ]; + +/* + * display the latency histogram + */ +static int cachefiles_histogram_show(struct seq_file *m, void *v) +{ + unsigned long index; + unsigned x, y, z, t; + + switch ((unsigned long) v) { + case 1: + seq_puts(m, "JIFS SECS LOOKUPS MKDIRS CREATES\n"); + return 0; + case 2: + seq_puts(m, "===== ===== ========= ========= =========\n"); + return 0; + default: + index = (unsigned long) v - 3; + x = atomic_read(&cachefiles_lookup_histogram[index]); + y = atomic_read(&cachefiles_mkdir_histogram[index]); + z = atomic_read(&cachefiles_create_histogram[index]); + if (x == 0 && y == 0 && z == 0) + return 0; + + t = (index * 1000) / HZ; + + seq_printf(m, "%4lu 0.%03u %9u %9u %9u\n", index, t, x, y, z); + return 0; + } +} + +/* + * set up the iterator to start reading from the first line + */ +static void *cachefiles_histogram_start(struct seq_file *m, loff_t *_pos) +{ + if ((unsigned long long)*_pos >= HZ + 2) + return NULL; + if (*_pos == 0) + *_pos = 1; + return (void *)(unsigned long) *_pos; +} + +/* + * move to the next line + */ +static void *cachefiles_histogram_next(struct seq_file *m, void *v, loff_t *pos) +{ + (*pos)++; + return (unsigned long long)*pos > HZ + 2 ? + NULL : (void *)(unsigned long) *pos; +} + +/* + * clean up after reading + */ +static void cachefiles_histogram_stop(struct seq_file *m, void *v) +{ +} + +static const struct seq_operations cachefiles_histogram_ops = { + .start = cachefiles_histogram_start, + .stop = cachefiles_histogram_stop, + .next = cachefiles_histogram_next, + .show = cachefiles_histogram_show, +}; + +/* + * open "/proc/fs/cachefiles/XXX" which provide statistics summaries + */ +static int cachefiles_histogram_open(struct inode *inode, struct file *file) +{ + return seq_open(file, &cachefiles_histogram_ops); +} + +static const struct file_operations cachefiles_histogram_fops = { + .owner = THIS_MODULE, + .open = cachefiles_histogram_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, +}; + +/* + * initialise the /proc/fs/cachefiles/ directory + */ +int __init cachefiles_proc_init(void) +{ + _enter(""); + + if (!proc_mkdir("fs/cachefiles", NULL)) + goto error_dir; + + if (!proc_create("fs/cachefiles/histogram", S_IFREG | 0444, NULL, + &cachefiles_histogram_fops)) + goto error_histogram; + + _leave(" = 0"); + return 0; + +error_histogram: + remove_proc_entry("fs/cachefiles", NULL); +error_dir: + _leave(" = -ENOMEM"); + return -ENOMEM; +} + +/* + * clean up the /proc/fs/cachefiles/ directory + */ +void cachefiles_proc_cleanup(void) +{ + remove_proc_entry("fs/cachefiles/histogram", NULL); + remove_proc_entry("fs/cachefiles", NULL); +} diff --git a/fs/cachefiles/rdwr.c b/fs/cachefiles/rdwr.c new file mode 100644 index 00000000000..a69787e7dd9 --- /dev/null +++ b/fs/cachefiles/rdwr.c @@ -0,0 +1,879 @@ +/* Storage object read/write + * + * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#include +#include +#include "internal.h" + +/* + * detect wake up events generated by the unlocking of pages in which we're + * interested + * - we use this to detect read completion of backing pages + * - the caller holds the waitqueue lock + */ +static int cachefiles_read_waiter(wait_queue_t *wait, unsigned mode, + int sync, void *_key) +{ + struct cachefiles_one_read *monitor = + container_of(wait, struct cachefiles_one_read, monitor); + struct cachefiles_object *object; + struct wait_bit_key *key = _key; + struct page *page = wait->private; + + ASSERT(key); + + _enter("{%lu},%u,%d,{%p,%u}", + monitor->netfs_page->index, mode, sync, + key->flags, key->bit_nr); + + if (key->flags != &page->flags || + key->bit_nr != PG_locked) + return 0; + + _debug("--- monitor %p %lx ---", page, page->flags); + + if (!PageUptodate(page) && !PageError(page)) + dump_stack(); + + /* remove from the waitqueue */ + list_del(&wait->task_list); + + /* move onto the action list and queue for FS-Cache thread pool */ + ASSERT(monitor->op); + + object = container_of(monitor->op->op.object, + struct cachefiles_object, fscache); + + spin_lock(&object->work_lock); + list_add_tail(&monitor->op_link, &monitor->op->to_do); + spin_unlock(&object->work_lock); + + fscache_enqueue_retrieval(monitor->op); + return 0; +} + +/* + * copy data from backing pages to netfs pages to complete a read operation + * - driven by FS-Cache's thread pool + */ +static void cachefiles_read_copier(struct fscache_operation *_op) +{ + struct cachefiles_one_read *monitor; + struct cachefiles_object *object; + struct fscache_retrieval *op; + struct pagevec pagevec; + int error, max; + + op = container_of(_op, struct fscache_retrieval, op); + object = container_of(op->op.object, + struct cachefiles_object, fscache); + + _enter("{ino=%lu}", object->backer->d_inode->i_ino); + + pagevec_init(&pagevec, 0); + + max = 8; + spin_lock_irq(&object->work_lock); + + while (!list_empty(&op->to_do)) { + monitor = list_entry(op->to_do.next, + struct cachefiles_one_read, op_link); + list_del(&monitor->op_link); + + spin_unlock_irq(&object->work_lock); + + _debug("- copy {%lu}", monitor->back_page->index); + + error = -EIO; + if (PageUptodate(monitor->back_page)) { + copy_highpage(monitor->netfs_page, monitor->back_page); + + pagevec_add(&pagevec, monitor->netfs_page); + fscache_mark_pages_cached(monitor->op, &pagevec); + error = 0; + } + + if (error) + cachefiles_io_error_obj( + object, + "Readpage failed on backing file %lx", + (unsigned long) monitor->back_page->flags); + + page_cache_release(monitor->back_page); + + fscache_end_io(op, monitor->netfs_page, error); + page_cache_release(monitor->netfs_page); + fscache_put_retrieval(op); + kfree(monitor); + + /* let the thread pool have some air occasionally */ + max--; + if (max < 0 || need_resched()) { + if (!list_empty(&op->to_do)) + fscache_enqueue_retrieval(op); + _leave(" [maxed out]"); + return; + } + + spin_lock_irq(&object->work_lock); + } + + spin_unlock_irq(&object->work_lock); + _leave(""); +} + +/* + * read the corresponding page to the given set from the backing file + * - an uncertain page is simply discarded, to be tried again another time + */ +static int cachefiles_read_backing_file_one(struct cachefiles_object *object, + struct fscache_retrieval *op, + struct page *netpage, + struct pagevec *pagevec) +{ + struct cachefiles_one_read *monitor; + struct address_space *bmapping; + struct page *newpage, *backpage; + int ret; + + _enter(""); + + pagevec_reinit(pagevec); + + _debug("read back %p{%lu,%d}", + netpage, netpage->index, page_count(netpage)); + + monitor = kzalloc(sizeof(*monitor), GFP_KERNEL); + if (!monitor) + goto nomem; + + monitor->netfs_page = netpage; + monitor->op = fscache_get_retrieval(op); + + init_waitqueue_func_entry(&monitor->monitor, cachefiles_read_waiter); + + /* attempt to get hold of the backing page */ + bmapping = object->backer->d_inode->i_mapping; + newpage = NULL; + + for (;;) { + backpage = find_get_page(bmapping, netpage->index); + if (backpage) + goto backing_page_already_present; + + if (!newpage) { + newpage = page_cache_alloc_cold(bmapping); + if (!newpage) + goto nomem_monitor; + } + + ret = add_to_page_cache(newpage, bmapping, + netpage->index, GFP_KERNEL); + if (ret == 0) + goto installed_new_backing_page; + if (ret != -EEXIST) + goto nomem_page; + } + + /* we've installed a new backing page, so now we need to add it + * to the LRU list and start it reading */ +installed_new_backing_page: + _debug("- new %p", newpage); + + backpage = newpage; + newpage = NULL; + + page_cache_get(backpage); + pagevec_add(pagevec, backpage); + __pagevec_lru_add_file(pagevec); + +read_backing_page: + ret = bmapping->a_ops->readpage(NULL, backpage); + if (ret < 0) + goto read_error; + + /* set the monitor to transfer the data across */ +monitor_backing_page: + _debug("- monitor add"); + + /* install the monitor */ + page_cache_get(monitor->netfs_page); + page_cache_get(backpage); + monitor->back_page = backpage; + monitor->monitor.private = backpage; + add_page_wait_queue(backpage, &monitor->monitor); + monitor = NULL; + + /* but the page may have been read before the monitor was installed, so + * the monitor may miss the event - so we have to ensure that we do get + * one in such a case */ + if (trylock_page(backpage)) { + _debug("jumpstart %p {%lx}", backpage, backpage->flags); + unlock_page(backpage); + } + goto success; + + /* if the backing page is already present, it can be in one of + * three states: read in progress, read failed or read okay */ +backing_page_already_present: + _debug("- present"); + + if (newpage) { + page_cache_release(newpage); + newpage = NULL; + } + + if (PageError(backpage)) + goto io_error; + + if (PageUptodate(backpage)) + goto backing_page_already_uptodate; + + if (!trylock_page(backpage)) + goto monitor_backing_page; + _debug("read %p {%lx}", backpage, backpage->flags); + goto read_backing_page; + + /* the backing page is already up to date, attach the netfs + * page to the pagecache and LRU and copy the data across */ +backing_page_already_uptodate: + _debug("- uptodate"); + + pagevec_add(pagevec, netpage); + fscache_mark_pages_cached(op, pagevec); + + copy_highpage(netpage, backpage); + fscache_end_io(op, netpage, 0); + +success: + _debug("success"); + ret = 0; + +out: + if (backpage) + page_cache_release(backpage); + if (monitor) { + fscache_put_retrieval(monitor->op); + kfree(monitor); + } + _leave(" = %d", ret); + return ret; + +read_error: + _debug("read error %d", ret); + if (ret == -ENOMEM) + goto out; +io_error: + cachefiles_io_error_obj(object, "Page read error on backing file"); + ret = -ENOBUFS; + goto out; + +nomem_page: + page_cache_release(newpage); +nomem_monitor: + fscache_put_retrieval(monitor->op); + kfree(monitor); +nomem: + _leave(" = -ENOMEM"); + return -ENOMEM; +} + +/* + * read a page from the cache or allocate a block in which to store it + * - cache withdrawal is prevented by the caller + * - returns -EINTR if interrupted + * - returns -ENOMEM if ran out of memory + * - returns -ENOBUFS if no buffers can be made available + * - returns -ENOBUFS if page is beyond EOF + * - if the page is backed by a block in the cache: + * - a read will be started which will call the callback on completion + * - 0 will be returned + * - else if the page is unbacked: + * - the metadata will be retained + * - -ENODATA will be returned + */ +int cachefiles_read_or_alloc_page(struct fscache_retrieval *op, + struct page *page, + gfp_t gfp) +{ + struct cachefiles_object *object; + struct cachefiles_cache *cache; + struct pagevec pagevec; + struct inode *inode; + sector_t block0, block; + unsigned shift; + int ret; + + object = container_of(op->op.object, + struct cachefiles_object, fscache); + cache = container_of(object->fscache.cache, + struct cachefiles_cache, cache); + + _enter("{%p},{%lx},,,", object, page->index); + + if (!object->backer) + return -ENOBUFS; + + inode = object->backer->d_inode; + ASSERT(S_ISREG(inode->i_mode)); + ASSERT(inode->i_mapping->a_ops->bmap); + ASSERT(inode->i_mapping->a_ops->readpages); + + /* calculate the shift required to use bmap */ + if (inode->i_sb->s_blocksize > PAGE_SIZE) + return -ENOBUFS; + + shift = PAGE_SHIFT - inode->i_sb->s_blocksize_bits; + + op->op.flags = FSCACHE_OP_FAST; + op->op.processor = cachefiles_read_copier; + + pagevec_init(&pagevec, 0); + + /* we assume the absence or presence of the first block is a good + * enough indication for the page as a whole + * - TODO: don't use bmap() for this as it is _not_ actually good + * enough for this as it doesn't indicate errors, but it's all we've + * got for the moment + */ + block0 = page->index; + block0 <<= shift; + + block = inode->i_mapping->a_ops->bmap(inode->i_mapping, block0); + _debug("%llx -> %llx", + (unsigned long long) block0, + (unsigned long long) block); + + if (block) { + /* submit the apparently valid page to the backing fs to be + * read from disk */ + ret = cachefiles_read_backing_file_one(object, op, page, + &pagevec); + } else if (cachefiles_has_space(cache, 0, 1) == 0) { + /* there's space in the cache we can use */ + pagevec_add(&pagevec, page); + fscache_mark_pages_cached(op, &pagevec); + ret = -ENODATA; + } else { + ret = -ENOBUFS; + } + + _leave(" = %d", ret); + return ret; +} + +/* + * read the corresponding pages to the given set from the backing file + * - any uncertain pages are simply discarded, to be tried again another time + */ +static int cachefiles_read_backing_file(struct cachefiles_object *object, + struct fscache_retrieval *op, + struct list_head *list, + struct pagevec *mark_pvec) +{ + struct cachefiles_one_read *monitor = NULL; + struct address_space *bmapping = object->backer->d_inode->i_mapping; + struct pagevec lru_pvec; + struct page *newpage = NULL, *netpage, *_n, *backpage = NULL; + int ret = 0; + + _enter(""); + + pagevec_init(&lru_pvec, 0); + + list_for_each_entry_safe(netpage, _n, list, lru) { + list_del(&netpage->lru); + + _debug("read back %p{%lu,%d}", + netpage, netpage->index, page_count(netpage)); + + if (!monitor) { + monitor = kzalloc(sizeof(*monitor), GFP_KERNEL); + if (!monitor) + goto nomem; + + monitor->op = fscache_get_retrieval(op); + init_waitqueue_func_entry(&monitor->monitor, + cachefiles_read_waiter); + } + + for (;;) { + backpage = find_get_page(bmapping, netpage->index); + if (backpage) + goto backing_page_already_present; + + if (!newpage) { + newpage = page_cache_alloc_cold(bmapping); + if (!newpage) + goto nomem; + } + + ret = add_to_page_cache(newpage, bmapping, + netpage->index, GFP_KERNEL); + if (ret == 0) + goto installed_new_backing_page; + if (ret != -EEXIST) + goto nomem; + } + + /* we've installed a new backing page, so now we need to add it + * to the LRU list and start it reading */ + installed_new_backing_page: + _debug("- new %p", newpage); + + backpage = newpage; + newpage = NULL; + + page_cache_get(backpage); + if (!pagevec_add(&lru_pvec, backpage)) + __pagevec_lru_add_file(&lru_pvec); + + reread_backing_page: + ret = bmapping->a_ops->readpage(NULL, backpage); + if (ret < 0) + goto read_error; + + /* add the netfs page to the pagecache and LRU, and set the + * monitor to transfer the data across */ + monitor_backing_page: + _debug("- monitor add"); + + ret = add_to_page_cache(netpage, op->mapping, netpage->index, + GFP_KERNEL); + if (ret < 0) { + if (ret == -EEXIST) { + page_cache_release(netpage); + continue; + } + goto nomem; + } + + page_cache_get(netpage); + if (!pagevec_add(&lru_pvec, netpage)) + __pagevec_lru_add_file(&lru_pvec); + + /* install a monitor */ + page_cache_get(netpage); + monitor->netfs_page = netpage; + + page_cache_get(backpage); + monitor->back_page = backpage; + monitor->monitor.private = backpage; + add_page_wait_queue(backpage, &monitor->monitor); + monitor = NULL; + + /* but the page may have been read before the monitor was + * installed, so the monitor may miss the event - so we have to + * ensure that we do get one in such a case */ + if (trylock_page(backpage)) { + _debug("2unlock %p {%lx}", backpage, backpage->flags); + unlock_page(backpage); + } + + page_cache_release(backpage); + backpage = NULL; + + page_cache_release(netpage); + netpage = NULL; + continue; + + /* if the backing page is already present, it can be in one of + * three states: read in progress, read failed or read okay */ + backing_page_already_present: + _debug("- present %p", backpage); + + if (PageError(backpage)) + goto io_error; + + if (PageUptodate(backpage)) + goto backing_page_already_uptodate; + + _debug("- not ready %p{%lx}", backpage, backpage->flags); + + if (!trylock_page(backpage)) + goto monitor_backing_page; + + if (PageError(backpage)) { + _debug("error %lx", backpage->flags); + unlock_page(backpage); + goto io_error; + } + + if (PageUptodate(backpage)) + goto backing_page_already_uptodate_unlock; + + /* we've locked a page that's neither up to date nor erroneous, + * so we need to attempt to read it again */ + goto reread_backing_page; + + /* the backing page is already up to date, attach the netfs + * page to the pagecache and LRU and copy the data across */ + backing_page_already_uptodate_unlock: + _debug("uptodate %lx", backpage->flags); + unlock_page(backpage); + backing_page_already_uptodate: + _debug("- uptodate"); + + ret = add_to_page_cache(netpage, op->mapping, netpage->index, + GFP_KERNEL); + if (ret < 0) { + if (ret == -EEXIST) { + page_cache_release(netpage); + continue; + } + goto nomem; + } + + copy_highpage(netpage, backpage); + + page_cache_release(backpage); + backpage = NULL; + + if (!pagevec_add(mark_pvec, netpage)) + fscache_mark_pages_cached(op, mark_pvec); + + page_cache_get(netpage); + if (!pagevec_add(&lru_pvec, netpage)) + __pagevec_lru_add_file(&lru_pvec); + + fscache_end_io(op, netpage, 0); + page_cache_release(netpage); + netpage = NULL; + continue; + } + + netpage = NULL; + + _debug("out"); + +out: + /* tidy up */ + pagevec_lru_add_file(&lru_pvec); + + if (newpage) + page_cache_release(newpage); + if (netpage) + page_cache_release(netpage); + if (backpage) + page_cache_release(backpage); + if (monitor) { + fscache_put_retrieval(op); + kfree(monitor); + } + + list_for_each_entry_safe(netpage, _n, list, lru) { + list_del(&netpage->lru); + page_cache_release(netpage); + } + + _leave(" = %d", ret); + return ret; + +nomem: + _debug("nomem"); + ret = -ENOMEM; + goto out; + +read_error: + _debug("read error %d", ret); + if (ret == -ENOMEM) + goto out; +io_error: + cachefiles_io_error_obj(object, "Page read error on backing file"); + ret = -ENOBUFS; + goto out; +} + +/* + * read a list of pages from the cache or allocate blocks in which to store + * them + */ +int cachefiles_read_or_alloc_pages(struct fscache_retrieval *op, + struct list_head *pages, + unsigned *nr_pages, + gfp_t gfp) +{ + struct cachefiles_object *object; + struct cachefiles_cache *cache; + struct list_head backpages; + struct pagevec pagevec; + struct inode *inode; + struct page *page, *_n; + unsigned shift, nrbackpages; + int ret, ret2, space; + + object = container_of(op->op.object, + struct cachefiles_object, fscache); + cache = container_of(object->fscache.cache, + struct cachefiles_cache, cache); + + _enter("{OBJ%x,%d},,%d,,", + object->fscache.debug_id, atomic_read(&op->op.usage), + *nr_pages); + + if (!object->backer) + return -ENOBUFS; + + space = 1; + if (cachefiles_has_space(cache, 0, *nr_pages) < 0) + space = 0; + + inode = object->backer->d_inode; + ASSERT(S_ISREG(inode->i_mode)); + ASSERT(inode->i_mapping->a_ops->bmap); + ASSERT(inode->i_mapping->a_ops->readpages); + + /* calculate the shift required to use bmap */ + if (inode->i_sb->s_blocksize > PAGE_SIZE) + return -ENOBUFS; + + shift = PAGE_SHIFT - inode->i_sb->s_blocksize_bits; + + pagevec_init(&pagevec, 0); + + op->op.flags = FSCACHE_OP_FAST; + op->op.processor = cachefiles_read_copier; + + INIT_LIST_HEAD(&backpages); + nrbackpages = 0; + + ret = space ? -ENODATA : -ENOBUFS; + list_for_each_entry_safe(page, _n, pages, lru) { + sector_t block0, block; + + /* we assume the absence or presence of the first block is a + * good enough indication for the page as a whole + * - TODO: don't use bmap() for this as it is _not_ actually + * good enough for this as it doesn't indicate errors, but + * it's all we've got for the moment + */ + block0 = page->index; + block0 <<= shift; + + block = inode->i_mapping->a_ops->bmap(inode->i_mapping, + block0); + _debug("%llx -> %llx", + (unsigned long long) block0, + (unsigned long long) block); + + if (block) { + /* we have data - add it to the list to give to the + * backing fs */ + list_move(&page->lru, &backpages); + (*nr_pages)--; + nrbackpages++; + } else if (space && pagevec_add(&pagevec, page) == 0) { + fscache_mark_pages_cached(op, &pagevec); + ret = -ENODATA; + } + } + + if (pagevec_count(&pagevec) > 0) + fscache_mark_pages_cached(op, &pagevec); + + if (list_empty(pages)) + ret = 0; + + /* submit the apparently valid pages to the backing fs to be read from + * disk */ + if (nrbackpages > 0) { + ret2 = cachefiles_read_backing_file(object, op, &backpages, + &pagevec); + if (ret2 == -ENOMEM || ret2 == -EINTR) + ret = ret2; + } + + if (pagevec_count(&pagevec) > 0) + fscache_mark_pages_cached(op, &pagevec); + + _leave(" = %d [nr=%u%s]", + ret, *nr_pages, list_empty(pages) ? " empty" : ""); + return ret; +} + +/* + * allocate a block in the cache in which to store a page + * - cache withdrawal is prevented by the caller + * - returns -EINTR if interrupted + * - returns -ENOMEM if ran out of memory + * - returns -ENOBUFS if no buffers can be made available + * - returns -ENOBUFS if page is beyond EOF + * - otherwise: + * - the metadata will be retained + * - 0 will be returned + */ +int cachefiles_allocate_page(struct fscache_retrieval *op, + struct page *page, + gfp_t gfp) +{ + struct cachefiles_object *object; + struct cachefiles_cache *cache; + struct pagevec pagevec; + int ret; + + object = container_of(op->op.object, + struct cachefiles_object, fscache); + cache = container_of(object->fscache.cache, + struct cachefiles_cache, cache); + + _enter("%p,{%lx},", object, page->index); + + ret = cachefiles_has_space(cache, 0, 1); + if (ret == 0) { + pagevec_init(&pagevec, 0); + pagevec_add(&pagevec, page); + fscache_mark_pages_cached(op, &pagevec); + } else { + ret = -ENOBUFS; + } + + _leave(" = %d", ret); + return ret; +} + +/* + * allocate blocks in the cache in which to store a set of pages + * - cache withdrawal is prevented by the caller + * - returns -EINTR if interrupted + * - returns -ENOMEM if ran out of memory + * - returns -ENOBUFS if some buffers couldn't be made available + * - returns -ENOBUFS if some pages are beyond EOF + * - otherwise: + * - -ENODATA will be returned + * - metadata will be retained for any page marked + */ +int cachefiles_allocate_pages(struct fscache_retrieval *op, + struct list_head *pages, + unsigned *nr_pages, + gfp_t gfp) +{ + struct cachefiles_object *object; + struct cachefiles_cache *cache; + struct pagevec pagevec; + struct page *page; + int ret; + + object = container_of(op->op.object, + struct cachefiles_object, fscache); + cache = container_of(object->fscache.cache, + struct cachefiles_cache, cache); + + _enter("%p,,,%d,", object, *nr_pages); + + ret = cachefiles_has_space(cache, 0, *nr_pages); + if (ret == 0) { + pagevec_init(&pagevec, 0); + + list_for_each_entry(page, pages, lru) { + if (pagevec_add(&pagevec, page) == 0) + fscache_mark_pages_cached(op, &pagevec); + } + + if (pagevec_count(&pagevec) > 0) + fscache_mark_pages_cached(op, &pagevec); + ret = -ENODATA; + } else { + ret = -ENOBUFS; + } + + _leave(" = %d", ret); + return ret; +} + +/* + * request a page be stored in the cache + * - cache withdrawal is prevented by the caller + * - this request may be ignored if there's no cache block available, in which + * case -ENOBUFS will be returned + * - if the op is in progress, 0 will be returned + */ +int cachefiles_write_page(struct fscache_storage *op, struct page *page) +{ + struct cachefiles_object *object; + struct cachefiles_cache *cache; + mm_segment_t old_fs; + struct file *file; + loff_t pos; + void *data; + int ret; + + ASSERT(op != NULL); + ASSERT(page != NULL); + + object = container_of(op->op.object, + struct cachefiles_object, fscache); + + _enter("%p,%p{%lx},,,", object, page, page->index); + + if (!object->backer) { + _leave(" = -ENOBUFS"); + return -ENOBUFS; + } + + ASSERT(S_ISREG(object->backer->d_inode->i_mode)); + + cache = container_of(object->fscache.cache, + struct cachefiles_cache, cache); + + /* write the page to the backing filesystem and let it store it in its + * own time */ + dget(object->backer); + mntget(cache->mnt); + file = dentry_open(object->backer, cache->mnt, O_RDWR, + cache->cache_cred); + if (IS_ERR(file)) { + ret = PTR_ERR(file); + } else { + ret = -EIO; + if (file->f_op->write) { + pos = (loff_t) page->index << PAGE_SHIFT; + data = kmap(page); + old_fs = get_fs(); + set_fs(KERNEL_DS); + ret = file->f_op->write( + file, (const void __user *) data, PAGE_SIZE, + &pos); + set_fs(old_fs); + kunmap(page); + if (ret != PAGE_SIZE) + ret = -EIO; + } + fput(file); + } + + if (ret < 0) { + if (ret == -EIO) + cachefiles_io_error_obj( + object, "Write page to backing file failed"); + ret = -ENOBUFS; + } + + _leave(" = %d", ret); + return ret; +} + +/* + * detach a backing block from a page + * - cache withdrawal is prevented by the caller + */ +void cachefiles_uncache_page(struct fscache_object *_object, struct page *page) +{ + struct cachefiles_object *object; + struct cachefiles_cache *cache; + + object = container_of(_object, struct cachefiles_object, fscache); + cache = container_of(object->fscache.cache, + struct cachefiles_cache, cache); + + _enter("%p,{%lu}", object, page->index); + + spin_unlock(&object->fscache.cookie->lock); +} diff --git a/fs/cachefiles/security.c b/fs/cachefiles/security.c new file mode 100644 index 00000000000..b5808cdb223 --- /dev/null +++ b/fs/cachefiles/security.c @@ -0,0 +1,116 @@ +/* CacheFiles security management + * + * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#include +#include +#include "internal.h" + +/* + * determine the security context within which we access the cache from within + * the kernel + */ +int cachefiles_get_security_ID(struct cachefiles_cache *cache) +{ + struct cred *new; + int ret; + + _enter("{%s}", cache->secctx); + + new = prepare_kernel_cred(current); + if (!new) { + ret = -ENOMEM; + goto error; + } + + if (cache->secctx) { + ret = set_security_override_from_ctx(new, cache->secctx); + if (ret < 0) { + put_cred(new); + printk(KERN_ERR "CacheFiles:" + " Security denies permission to nominate" + " security context: error %d\n", + ret); + goto error; + } + } + + cache->cache_cred = new; + ret = 0; +error: + _leave(" = %d", ret); + return ret; +} + +/* + * see if mkdir and create can be performed in the root directory + */ +static int cachefiles_check_cache_dir(struct cachefiles_cache *cache, + struct dentry *root) +{ + int ret; + + ret = security_inode_mkdir(root->d_inode, root, 0); + if (ret < 0) { + printk(KERN_ERR "CacheFiles:" + " Security denies permission to make dirs: error %d", + ret); + return ret; + } + + ret = security_inode_create(root->d_inode, root, 0); + if (ret < 0) + printk(KERN_ERR "CacheFiles:" + " Security denies permission to create files: error %d", + ret); + + return ret; +} + +/* + * check the security details of the on-disk cache + * - must be called with security override in force + */ +int cachefiles_determine_cache_security(struct cachefiles_cache *cache, + struct dentry *root, + const struct cred **_saved_cred) +{ + struct cred *new; + int ret; + + _enter(""); + + /* duplicate the cache creds for COW (the override is currently in + * force, so we can use prepare_creds() to do this) */ + new = prepare_creds(); + if (!new) + return -ENOMEM; + + cachefiles_end_secure(cache, *_saved_cred); + + /* use the cache root dir's security context as the basis with + * which create files */ + ret = set_create_files_as(new, root->d_inode); + if (ret < 0) { + _leave(" = %d [cfa]", ret); + return ret; + } + + put_cred(cache->cache_cred); + cache->cache_cred = new; + + cachefiles_begin_secure(cache, _saved_cred); + ret = cachefiles_check_cache_dir(cache, root); + + if (ret == -EOPNOTSUPP) + ret = 0; + _leave(" = %d", ret); + return ret; +} diff --git a/fs/cachefiles/xattr.c b/fs/cachefiles/xattr.c new file mode 100644 index 00000000000..f3e7a0bf068 --- /dev/null +++ b/fs/cachefiles/xattr.c @@ -0,0 +1,291 @@ +/* CacheFiles extended attribute management + * + * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#include +#include +#include +#include +#include +#include +#include +#include "internal.h" + +static const char cachefiles_xattr_cache[] = + XATTR_USER_PREFIX "CacheFiles.cache"; + +/* + * check the type label on an object + * - done using xattrs + */ +int cachefiles_check_object_type(struct cachefiles_object *object) +{ + struct dentry *dentry = object->dentry; + char type[3], xtype[3]; + int ret; + + ASSERT(dentry); + ASSERT(dentry->d_inode); + + if (!object->fscache.cookie) + strcpy(type, "C3"); + else + snprintf(type, 3, "%02x", object->fscache.cookie->def->type); + + _enter("%p{%s}", object, type); + + /* attempt to install a type label directly */ + ret = vfs_setxattr(dentry, cachefiles_xattr_cache, type, 2, + XATTR_CREATE); + if (ret == 0) { + _debug("SET"); /* we succeeded */ + goto error; + } + + if (ret != -EEXIST) { + kerror("Can't set xattr on %*.*s [%lu] (err %d)", + dentry->d_name.len, dentry->d_name.len, + dentry->d_name.name, dentry->d_inode->i_ino, + -ret); + goto error; + } + + /* read the current type label */ + ret = vfs_getxattr(dentry, cachefiles_xattr_cache, xtype, 3); + if (ret < 0) { + if (ret == -ERANGE) + goto bad_type_length; + + kerror("Can't read xattr on %*.*s [%lu] (err %d)", + dentry->d_name.len, dentry->d_name.len, + dentry->d_name.name, dentry->d_inode->i_ino, + -ret); + goto error; + } + + /* check the type is what we're expecting */ + if (ret != 2) + goto bad_type_length; + + if (xtype[0] != type[0] || xtype[1] != type[1]) + goto bad_type; + + ret = 0; + +error: + _leave(" = %d", ret); + return ret; + +bad_type_length: + kerror("Cache object %lu type xattr length incorrect", + dentry->d_inode->i_ino); + ret = -EIO; + goto error; + +bad_type: + xtype[2] = 0; + kerror("Cache object %*.*s [%lu] type %s not %s", + dentry->d_name.len, dentry->d_name.len, + dentry->d_name.name, dentry->d_inode->i_ino, + xtype, type); + ret = -EIO; + goto error; +} + +/* + * set the state xattr on a cache file + */ +int cachefiles_set_object_xattr(struct cachefiles_object *object, + struct cachefiles_xattr *auxdata) +{ + struct dentry *dentry = object->dentry; + int ret; + + ASSERT(object->fscache.cookie); + ASSERT(dentry); + + _enter("%p,#%d", object, auxdata->len); + + /* attempt to install the cache metadata directly */ + _debug("SET %s #%u", object->fscache.cookie->def->name, auxdata->len); + + ret = vfs_setxattr(dentry, cachefiles_xattr_cache, + &auxdata->type, auxdata->len, + XATTR_CREATE); + if (ret < 0 && ret != -ENOMEM) + cachefiles_io_error_obj( + object, + "Failed to set xattr with error %d", ret); + + _leave(" = %d", ret); + return ret; +} + +/* + * update the state xattr on a cache file + */ +int cachefiles_update_object_xattr(struct cachefiles_object *object, + struct cachefiles_xattr *auxdata) +{ + struct dentry *dentry = object->dentry; + int ret; + + ASSERT(object->fscache.cookie); + ASSERT(dentry); + + _enter("%p,#%d", object, auxdata->len); + + /* attempt to install the cache metadata directly */ + _debug("SET %s #%u", object->fscache.cookie->def->name, auxdata->len); + + ret = vfs_setxattr(dentry, cachefiles_xattr_cache, + &auxdata->type, auxdata->len, + XATTR_REPLACE); + if (ret < 0 && ret != -ENOMEM) + cachefiles_io_error_obj( + object, + "Failed to update xattr with error %d", ret); + + _leave(" = %d", ret); + return ret; +} + +/* + * check the state xattr on a cache file + * - return -ESTALE if the object should be deleted + */ +int cachefiles_check_object_xattr(struct cachefiles_object *object, + struct cachefiles_xattr *auxdata) +{ + struct cachefiles_xattr *auxbuf; + struct dentry *dentry = object->dentry; + int ret; + + _enter("%p,#%d", object, auxdata->len); + + ASSERT(dentry); + ASSERT(dentry->d_inode); + + auxbuf = kmalloc(sizeof(struct cachefiles_xattr) + 512, GFP_KERNEL); + if (!auxbuf) { + _leave(" = -ENOMEM"); + return -ENOMEM; + } + + /* read the current type label */ + ret = vfs_getxattr(dentry, cachefiles_xattr_cache, + &auxbuf->type, 512 + 1); + if (ret < 0) { + if (ret == -ENODATA) + goto stale; /* no attribute - power went off + * mid-cull? */ + + if (ret == -ERANGE) + goto bad_type_length; + + cachefiles_io_error_obj(object, + "Can't read xattr on %lu (err %d)", + dentry->d_inode->i_ino, -ret); + goto error; + } + + /* check the on-disk object */ + if (ret < 1) + goto bad_type_length; + + if (auxbuf->type != auxdata->type) + goto stale; + + auxbuf->len = ret; + + /* consult the netfs */ + if (object->fscache.cookie->def->check_aux) { + enum fscache_checkaux result; + unsigned int dlen; + + dlen = auxbuf->len - 1; + + _debug("checkaux %s #%u", + object->fscache.cookie->def->name, dlen); + + result = fscache_check_aux(&object->fscache, + &auxbuf->data, dlen); + + switch (result) { + /* entry okay as is */ + case FSCACHE_CHECKAUX_OKAY: + goto okay; + + /* entry requires update */ + case FSCACHE_CHECKAUX_NEEDS_UPDATE: + break; + + /* entry requires deletion */ + case FSCACHE_CHECKAUX_OBSOLETE: + goto stale; + + default: + BUG(); + } + + /* update the current label */ + ret = vfs_setxattr(dentry, cachefiles_xattr_cache, + &auxdata->type, auxdata->len, + XATTR_REPLACE); + if (ret < 0) { + cachefiles_io_error_obj(object, + "Can't update xattr on %lu" + " (error %d)", + dentry->d_inode->i_ino, -ret); + goto error; + } + } + +okay: + ret = 0; + +error: + kfree(auxbuf); + _leave(" = %d", ret); + return ret; + +bad_type_length: + kerror("Cache object %lu xattr length incorrect", + dentry->d_inode->i_ino); + ret = -EIO; + goto error; + +stale: + ret = -ESTALE; + goto error; +} + +/* + * remove the object's xattr to mark it stale + */ +int cachefiles_remove_object_xattr(struct cachefiles_cache *cache, + struct dentry *dentry) +{ + int ret; + + ret = vfs_removexattr(dentry, cachefiles_xattr_cache); + if (ret < 0) { + if (ret == -ENOENT || ret == -ENODATA) + ret = 0; + else if (ret != -ENOMEM) + cachefiles_io_error(cache, + "Can't remove xattr from %lu" + " (error %d)", + dentry->d_inode->i_ino, -ret); + } + + _leave(" = %d", ret); + return ret; +} -- cgit v1.2.3-70-g09d2 From 9b3f26c9110dcea62716aca9b8c68ceb482227ef Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:41 +0100 Subject: FS-Cache: Make kAFS use FS-Cache The attached patch makes the kAFS filesystem in fs/afs/ use FS-Cache, and through it any attached caches. The kAFS filesystem will use caching automatically if it's available. Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Al Viro Tested-by: Daire Byrne --- fs/afs/Kconfig | 8 + fs/afs/Makefile | 3 + fs/afs/cache.c | 503 ++++++++++++++++++++++++++++++++++------------------- fs/afs/cache.h | 15 +- fs/afs/cell.c | 16 +- fs/afs/file.c | 220 +++++++++++++++-------- fs/afs/inode.c | 31 ++-- fs/afs/internal.h | 53 +++--- fs/afs/main.c | 27 +-- fs/afs/mntpt.c | 4 +- fs/afs/vlocation.c | 25 +-- fs/afs/volume.c | 14 +- fs/afs/write.c | 21 +++ 13 files changed, 582 insertions(+), 358 deletions(-) (limited to 'fs') diff --git a/fs/afs/Kconfig b/fs/afs/Kconfig index e7b522fe15e..5c4e61d3c77 100644 --- a/fs/afs/Kconfig +++ b/fs/afs/Kconfig @@ -19,3 +19,11 @@ config AFS_DEBUG See for more information. If unsure, say N. + +config AFS_FSCACHE + bool "Provide AFS client caching support (EXPERIMENTAL)" + depends on EXPERIMENTAL + depends on AFS_FS=m && FSCACHE || AFS_FS=y && FSCACHE=y + help + Say Y here if you want AFS data to be cached locally on disk through + the generic filesystem cache manager diff --git a/fs/afs/Makefile b/fs/afs/Makefile index a66671082cf..4f64b95d57b 100644 --- a/fs/afs/Makefile +++ b/fs/afs/Makefile @@ -2,7 +2,10 @@ # Makefile for Red Hat Linux AFS client. # +afs-cache-$(CONFIG_AFS_FSCACHE) := cache.o + kafs-objs := \ + $(afs-cache-y) \ callback.o \ cell.o \ cmservice.o \ diff --git a/fs/afs/cache.c b/fs/afs/cache.c index de0d7de69ed..e2b1d3f1651 100644 --- a/fs/afs/cache.c +++ b/fs/afs/cache.c @@ -1,6 +1,6 @@ /* AFS caching stuff * - * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. + * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * * This program is free software; you can redistribute it and/or @@ -9,248 +9,395 @@ * 2 of the License, or (at your option) any later version. */ -#ifdef AFS_CACHING_SUPPORT -static cachefs_match_val_t afs_cell_cache_match(void *target, - const void *entry); -static void afs_cell_cache_update(void *source, void *entry); - -struct cachefs_index_def afs_cache_cell_index_def = { - .name = "cell_ix", - .data_size = sizeof(struct afs_cache_cell), - .keys[0] = { CACHEFS_INDEX_KEYS_ASCIIZ, 64 }, - .match = afs_cell_cache_match, - .update = afs_cell_cache_update, +#include +#include +#include "internal.h" + +static uint16_t afs_cell_cache_get_key(const void *cookie_netfs_data, + void *buffer, uint16_t buflen); +static uint16_t afs_cell_cache_get_aux(const void *cookie_netfs_data, + void *buffer, uint16_t buflen); +static enum fscache_checkaux afs_cell_cache_check_aux(void *cookie_netfs_data, + const void *buffer, + uint16_t buflen); + +static uint16_t afs_vlocation_cache_get_key(const void *cookie_netfs_data, + void *buffer, uint16_t buflen); +static uint16_t afs_vlocation_cache_get_aux(const void *cookie_netfs_data, + void *buffer, uint16_t buflen); +static enum fscache_checkaux afs_vlocation_cache_check_aux( + void *cookie_netfs_data, const void *buffer, uint16_t buflen); + +static uint16_t afs_volume_cache_get_key(const void *cookie_netfs_data, + void *buffer, uint16_t buflen); + +static uint16_t afs_vnode_cache_get_key(const void *cookie_netfs_data, + void *buffer, uint16_t buflen); +static void afs_vnode_cache_get_attr(const void *cookie_netfs_data, + uint64_t *size); +static uint16_t afs_vnode_cache_get_aux(const void *cookie_netfs_data, + void *buffer, uint16_t buflen); +static enum fscache_checkaux afs_vnode_cache_check_aux(void *cookie_netfs_data, + const void *buffer, + uint16_t buflen); +static void afs_vnode_cache_now_uncached(void *cookie_netfs_data); + +struct fscache_netfs afs_cache_netfs = { + .name = "afs", + .version = 0, +}; + +struct fscache_cookie_def afs_cell_cache_index_def = { + .name = "AFS.cell", + .type = FSCACHE_COOKIE_TYPE_INDEX, + .get_key = afs_cell_cache_get_key, + .get_aux = afs_cell_cache_get_aux, + .check_aux = afs_cell_cache_check_aux, +}; + +struct fscache_cookie_def afs_vlocation_cache_index_def = { + .name = "AFS.vldb", + .type = FSCACHE_COOKIE_TYPE_INDEX, + .get_key = afs_vlocation_cache_get_key, + .get_aux = afs_vlocation_cache_get_aux, + .check_aux = afs_vlocation_cache_check_aux, +}; + +struct fscache_cookie_def afs_volume_cache_index_def = { + .name = "AFS.volume", + .type = FSCACHE_COOKIE_TYPE_INDEX, + .get_key = afs_volume_cache_get_key, +}; + +struct fscache_cookie_def afs_vnode_cache_index_def = { + .name = "AFS.vnode", + .type = FSCACHE_COOKIE_TYPE_DATAFILE, + .get_key = afs_vnode_cache_get_key, + .get_attr = afs_vnode_cache_get_attr, + .get_aux = afs_vnode_cache_get_aux, + .check_aux = afs_vnode_cache_check_aux, + .now_uncached = afs_vnode_cache_now_uncached, }; -#endif /* - * match a cell record obtained from the cache + * set the key for the index entry */ -#ifdef AFS_CACHING_SUPPORT -static cachefs_match_val_t afs_cell_cache_match(void *target, - const void *entry) +static uint16_t afs_cell_cache_get_key(const void *cookie_netfs_data, + void *buffer, uint16_t bufmax) { - const struct afs_cache_cell *ccell = entry; - struct afs_cell *cell = target; + const struct afs_cell *cell = cookie_netfs_data; + uint16_t klen; - _enter("{%s},{%s}", ccell->name, cell->name); + _enter("%p,%p,%u", cell, buffer, bufmax); - if (strncmp(ccell->name, cell->name, sizeof(ccell->name)) == 0) { - _leave(" = SUCCESS"); - return CACHEFS_MATCH_SUCCESS; - } + klen = strlen(cell->name); + if (klen > bufmax) + return 0; - _leave(" = FAILED"); - return CACHEFS_MATCH_FAILED; + memcpy(buffer, cell->name, klen); + return klen; } -#endif /* - * update a cell record in the cache + * provide new auxilliary cache data */ -#ifdef AFS_CACHING_SUPPORT -static void afs_cell_cache_update(void *source, void *entry) +static uint16_t afs_cell_cache_get_aux(const void *cookie_netfs_data, + void *buffer, uint16_t bufmax) { - struct afs_cache_cell *ccell = entry; - struct afs_cell *cell = source; + const struct afs_cell *cell = cookie_netfs_data; + uint16_t dlen; - _enter("%p,%p", source, entry); + _enter("%p,%p,%u", cell, buffer, bufmax); - strncpy(ccell->name, cell->name, sizeof(ccell->name)); + dlen = cell->vl_naddrs * sizeof(cell->vl_addrs[0]); + dlen = min(dlen, bufmax); + dlen &= ~(sizeof(cell->vl_addrs[0]) - 1); - memcpy(ccell->vl_servers, - cell->vl_addrs, - min(sizeof(ccell->vl_servers), sizeof(cell->vl_addrs))); + memcpy(buffer, cell->vl_addrs, dlen); + return dlen; +} +/* + * check that the auxilliary data indicates that the entry is still valid + */ +static enum fscache_checkaux afs_cell_cache_check_aux(void *cookie_netfs_data, + const void *buffer, + uint16_t buflen) +{ + _leave(" = OKAY"); + return FSCACHE_CHECKAUX_OKAY; } -#endif - -#ifdef AFS_CACHING_SUPPORT -static cachefs_match_val_t afs_vlocation_cache_match(void *target, - const void *entry); -static void afs_vlocation_cache_update(void *source, void *entry); - -struct cachefs_index_def afs_vlocation_cache_index_def = { - .name = "vldb", - .data_size = sizeof(struct afs_cache_vlocation), - .keys[0] = { CACHEFS_INDEX_KEYS_ASCIIZ, 64 }, - .match = afs_vlocation_cache_match, - .update = afs_vlocation_cache_update, -}; -#endif +/*****************************************************************************/ /* - * match a VLDB record stored in the cache - * - may also load target from entry + * set the key for the index entry */ -#ifdef AFS_CACHING_SUPPORT -static cachefs_match_val_t afs_vlocation_cache_match(void *target, - const void *entry) +static uint16_t afs_vlocation_cache_get_key(const void *cookie_netfs_data, + void *buffer, uint16_t bufmax) { - const struct afs_cache_vlocation *vldb = entry; - struct afs_vlocation *vlocation = target; + const struct afs_vlocation *vlocation = cookie_netfs_data; + uint16_t klen; + + _enter("{%s},%p,%u", vlocation->vldb.name, buffer, bufmax); + + klen = strnlen(vlocation->vldb.name, sizeof(vlocation->vldb.name)); + if (klen > bufmax) + return 0; - _enter("{%s},{%s}", vlocation->vldb.name, vldb->name); + memcpy(buffer, vlocation->vldb.name, klen); - if (strncmp(vlocation->vldb.name, vldb->name, sizeof(vldb->name)) == 0 - ) { - if (!vlocation->valid || - vlocation->vldb.rtime == vldb->rtime + _leave(" = %u", klen); + return klen; +} + +/* + * provide new auxilliary cache data + */ +static uint16_t afs_vlocation_cache_get_aux(const void *cookie_netfs_data, + void *buffer, uint16_t bufmax) +{ + const struct afs_vlocation *vlocation = cookie_netfs_data; + uint16_t dlen; + + _enter("{%s},%p,%u", vlocation->vldb.name, buffer, bufmax); + + dlen = sizeof(struct afs_cache_vlocation); + dlen -= offsetof(struct afs_cache_vlocation, nservers); + if (dlen > bufmax) + return 0; + + memcpy(buffer, (uint8_t *)&vlocation->vldb.nservers, dlen); + + _leave(" = %u", dlen); + return dlen; +} + +/* + * check that the auxilliary data indicates that the entry is still valid + */ +static +enum fscache_checkaux afs_vlocation_cache_check_aux(void *cookie_netfs_data, + const void *buffer, + uint16_t buflen) +{ + const struct afs_cache_vlocation *cvldb; + struct afs_vlocation *vlocation = cookie_netfs_data; + uint16_t dlen; + + _enter("{%s},%p,%u", vlocation->vldb.name, buffer, buflen); + + /* check the size of the data is what we're expecting */ + dlen = sizeof(struct afs_cache_vlocation); + dlen -= offsetof(struct afs_cache_vlocation, nservers); + if (dlen != buflen) + return FSCACHE_CHECKAUX_OBSOLETE; + + cvldb = container_of(buffer, struct afs_cache_vlocation, nservers); + + /* if what's on disk is more valid than what's in memory, then use the + * VL record from the cache */ + if (!vlocation->valid || vlocation->vldb.rtime == cvldb->rtime) { + memcpy((uint8_t *)&vlocation->vldb.nservers, buffer, dlen); + vlocation->valid = 1; + _leave(" = SUCCESS [c->m]"); + return FSCACHE_CHECKAUX_OKAY; + } + + /* need to update the cache if the cached info differs */ + if (memcmp(&vlocation->vldb, buffer, dlen) != 0) { + /* delete if the volume IDs for this name differ */ + if (memcmp(&vlocation->vldb.vid, &cvldb->vid, + sizeof(cvldb->vid)) != 0 ) { - vlocation->vldb = *vldb; - vlocation->valid = 1; - _leave(" = SUCCESS [c->m]"); - return CACHEFS_MATCH_SUCCESS; - } else if (memcmp(&vlocation->vldb, vldb, sizeof(*vldb)) != 0) { - /* delete if VIDs for this name differ */ - if (memcmp(&vlocation->vldb.vid, - &vldb->vid, - sizeof(vldb->vid)) != 0) { - _leave(" = DELETE"); - return CACHEFS_MATCH_SUCCESS_DELETE; - } - - _leave(" = UPDATE"); - return CACHEFS_MATCH_SUCCESS_UPDATE; - } else { - _leave(" = SUCCESS"); - return CACHEFS_MATCH_SUCCESS; + _leave(" = OBSOLETE"); + return FSCACHE_CHECKAUX_OBSOLETE; } + + _leave(" = UPDATE"); + return FSCACHE_CHECKAUX_NEEDS_UPDATE; } - _leave(" = FAILED"); - return CACHEFS_MATCH_FAILED; + _leave(" = OKAY"); + return FSCACHE_CHECKAUX_OKAY; } -#endif +/*****************************************************************************/ /* - * update a VLDB record stored in the cache + * set the key for the volume index entry */ -#ifdef AFS_CACHING_SUPPORT -static void afs_vlocation_cache_update(void *source, void *entry) +static uint16_t afs_volume_cache_get_key(const void *cookie_netfs_data, + void *buffer, uint16_t bufmax) { - struct afs_cache_vlocation *vldb = entry; - struct afs_vlocation *vlocation = source; + const struct afs_volume *volume = cookie_netfs_data; + uint16_t klen; + + _enter("{%u},%p,%u", volume->type, buffer, bufmax); + + klen = sizeof(volume->type); + if (klen > bufmax) + return 0; - _enter(""); + memcpy(buffer, &volume->type, sizeof(volume->type)); + + _leave(" = %u", klen); + return klen; - *vldb = vlocation->vldb; } -#endif - -#ifdef AFS_CACHING_SUPPORT -static cachefs_match_val_t afs_volume_cache_match(void *target, - const void *entry); -static void afs_volume_cache_update(void *source, void *entry); - -struct cachefs_index_def afs_volume_cache_index_def = { - .name = "volume", - .data_size = sizeof(struct afs_cache_vhash), - .keys[0] = { CACHEFS_INDEX_KEYS_BIN, 1 }, - .keys[1] = { CACHEFS_INDEX_KEYS_BIN, 1 }, - .match = afs_volume_cache_match, - .update = afs_volume_cache_update, -}; -#endif +/*****************************************************************************/ /* - * match a volume hash record stored in the cache + * set the key for the index entry */ -#ifdef AFS_CACHING_SUPPORT -static cachefs_match_val_t afs_volume_cache_match(void *target, - const void *entry) +static uint16_t afs_vnode_cache_get_key(const void *cookie_netfs_data, + void *buffer, uint16_t bufmax) { - const struct afs_cache_vhash *vhash = entry; - struct afs_volume *volume = target; + const struct afs_vnode *vnode = cookie_netfs_data; + uint16_t klen; - _enter("{%u},{%u}", volume->type, vhash->vtype); + _enter("{%x,%x,%llx},%p,%u", + vnode->fid.vnode, vnode->fid.unique, vnode->status.data_version, + buffer, bufmax); - if (volume->type == vhash->vtype) { - _leave(" = SUCCESS"); - return CACHEFS_MATCH_SUCCESS; - } + klen = sizeof(vnode->fid.vnode); + if (klen > bufmax) + return 0; + + memcpy(buffer, &vnode->fid.vnode, sizeof(vnode->fid.vnode)); - _leave(" = FAILED"); - return CACHEFS_MATCH_FAILED; + _leave(" = %u", klen); + return klen; } -#endif /* - * update a volume hash record stored in the cache + * provide updated file attributes */ -#ifdef AFS_CACHING_SUPPORT -static void afs_volume_cache_update(void *source, void *entry) +static void afs_vnode_cache_get_attr(const void *cookie_netfs_data, + uint64_t *size) { - struct afs_cache_vhash *vhash = entry; - struct afs_volume *volume = source; + const struct afs_vnode *vnode = cookie_netfs_data; - _enter(""); + _enter("{%x,%x,%llx},", + vnode->fid.vnode, vnode->fid.unique, + vnode->status.data_version); - vhash->vtype = volume->type; + *size = vnode->status.size; } -#endif - -#ifdef AFS_CACHING_SUPPORT -static cachefs_match_val_t afs_vnode_cache_match(void *target, - const void *entry); -static void afs_vnode_cache_update(void *source, void *entry); - -struct cachefs_index_def afs_vnode_cache_index_def = { - .name = "vnode", - .data_size = sizeof(struct afs_cache_vnode), - .keys[0] = { CACHEFS_INDEX_KEYS_BIN, 4 }, - .match = afs_vnode_cache_match, - .update = afs_vnode_cache_update, -}; -#endif /* - * match a vnode record stored in the cache + * provide new auxilliary cache data + */ +static uint16_t afs_vnode_cache_get_aux(const void *cookie_netfs_data, + void *buffer, uint16_t bufmax) +{ + const struct afs_vnode *vnode = cookie_netfs_data; + uint16_t dlen; + + _enter("{%x,%x,%Lx},%p,%u", + vnode->fid.vnode, vnode->fid.unique, vnode->status.data_version, + buffer, bufmax); + + dlen = sizeof(vnode->fid.unique) + sizeof(vnode->status.data_version); + if (dlen > bufmax) + return 0; + + memcpy(buffer, &vnode->fid.unique, sizeof(vnode->fid.unique)); + buffer += sizeof(vnode->fid.unique); + memcpy(buffer, &vnode->status.data_version, + sizeof(vnode->status.data_version)); + + _leave(" = %u", dlen); + return dlen; +} + +/* + * check that the auxilliary data indicates that the entry is still valid */ -#ifdef AFS_CACHING_SUPPORT -static cachefs_match_val_t afs_vnode_cache_match(void *target, - const void *entry) +static enum fscache_checkaux afs_vnode_cache_check_aux(void *cookie_netfs_data, + const void *buffer, + uint16_t buflen) { - const struct afs_cache_vnode *cvnode = entry; - struct afs_vnode *vnode = target; - - _enter("{%x,%x,%Lx},{%x,%x,%Lx}", - vnode->fid.vnode, - vnode->fid.unique, - vnode->status.version, - cvnode->vnode_id, - cvnode->vnode_unique, - cvnode->data_version); - - if (vnode->fid.vnode != cvnode->vnode_id) { - _leave(" = FAILED"); - return CACHEFS_MATCH_FAILED; + struct afs_vnode *vnode = cookie_netfs_data; + uint16_t dlen; + + _enter("{%x,%x,%llx},%p,%u", + vnode->fid.vnode, vnode->fid.unique, vnode->status.data_version, + buffer, buflen); + + /* check the size of the data is what we're expecting */ + dlen = sizeof(vnode->fid.unique) + sizeof(vnode->status.data_version); + if (dlen != buflen) { + _leave(" = OBSOLETE [len %hx != %hx]", dlen, buflen); + return FSCACHE_CHECKAUX_OBSOLETE; } - if (vnode->fid.unique != cvnode->vnode_unique || - vnode->status.version != cvnode->data_version) { - _leave(" = DELETE"); - return CACHEFS_MATCH_SUCCESS_DELETE; + if (memcmp(buffer, + &vnode->fid.unique, + sizeof(vnode->fid.unique) + ) != 0) { + unsigned unique; + + memcpy(&unique, buffer, sizeof(unique)); + + _leave(" = OBSOLETE [uniq %x != %x]", + unique, vnode->fid.unique); + return FSCACHE_CHECKAUX_OBSOLETE; + } + + if (memcmp(buffer + sizeof(vnode->fid.unique), + &vnode->status.data_version, + sizeof(vnode->status.data_version) + ) != 0) { + afs_dataversion_t version; + + memcpy(&version, buffer + sizeof(vnode->fid.unique), + sizeof(version)); + + _leave(" = OBSOLETE [vers %llx != %llx]", + version, vnode->status.data_version); + return FSCACHE_CHECKAUX_OBSOLETE; } _leave(" = SUCCESS"); - return CACHEFS_MATCH_SUCCESS; + return FSCACHE_CHECKAUX_OKAY; } -#endif /* - * update a vnode record stored in the cache + * indication the cookie is no longer uncached + * - this function is called when the backing store currently caching a cookie + * is removed + * - the netfs should use this to clean up any markers indicating cached pages + * - this is mandatory for any object that may have data */ -#ifdef AFS_CACHING_SUPPORT -static void afs_vnode_cache_update(void *source, void *entry) +static void afs_vnode_cache_now_uncached(void *cookie_netfs_data) { - struct afs_cache_vnode *cvnode = entry; - struct afs_vnode *vnode = source; + struct afs_vnode *vnode = cookie_netfs_data; + struct pagevec pvec; + pgoff_t first; + int loop, nr_pages; + + _enter("{%x,%x,%Lx}", + vnode->fid.vnode, vnode->fid.unique, vnode->status.data_version); + + pagevec_init(&pvec, 0); + first = 0; + + for (;;) { + /* grab a bunch of pages to clean */ + nr_pages = pagevec_lookup(&pvec, vnode->vfs_inode.i_mapping, + first, + PAGEVEC_SIZE - pagevec_count(&pvec)); + if (!nr_pages) + break; - _enter(""); + for (loop = 0; loop < nr_pages; loop++) + ClearPageFsCache(pvec.pages[loop]); + + first = pvec.pages[nr_pages - 1]->index + 1; + + pvec.nr = nr_pages; + pagevec_release(&pvec); + cond_resched(); + } - cvnode->vnode_id = vnode->fid.vnode; - cvnode->vnode_unique = vnode->fid.unique; - cvnode->data_version = vnode->status.version; + _leave(""); } -#endif diff --git a/fs/afs/cache.h b/fs/afs/cache.h index 36a3642cf90..5c4f6b499e9 100644 --- a/fs/afs/cache.h +++ b/fs/afs/cache.h @@ -1,6 +1,6 @@ /* AFS local cache management interface * - * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved. + * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * * This program is free software; you can redistribute it and/or @@ -9,15 +9,4 @@ * 2 of the License, or (at your option) any later version. */ -#ifndef AFS_CACHE_H -#define AFS_CACHE_H - -#undef AFS_CACHING_SUPPORT - -#include -#ifdef AFS_CACHING_SUPPORT -#include -#endif -#include "types.h" - -#endif /* AFS_CACHE_H */ +#include diff --git a/fs/afs/cell.c b/fs/afs/cell.c index 5e1df14e16b..e19c13f059e 100644 --- a/fs/afs/cell.c +++ b/fs/afs/cell.c @@ -147,12 +147,11 @@ struct afs_cell *afs_cell_create(const char *name, char *vllist) if (ret < 0) goto error; -#ifdef AFS_CACHING_SUPPORT - /* put it up for caching */ - cachefs_acquire_cookie(afs_cache_netfs.primary_index, - &afs_vlocation_cache_index_def, - cell, - &cell->cache); +#ifdef CONFIG_AFS_FSCACHE + /* put it up for caching (this never returns an error) */ + cell->cache = fscache_acquire_cookie(afs_cache_netfs.primary_index, + &afs_cell_cache_index_def, + cell); #endif /* add to the cell lists */ @@ -362,10 +361,9 @@ static void afs_cell_destroy(struct afs_cell *cell) list_del_init(&cell->proc_link); up_write(&afs_proc_cells_sem); -#ifdef AFS_CACHING_SUPPORT - cachefs_relinquish_cookie(cell->cache, 0); +#ifdef CONFIG_AFS_FSCACHE + fscache_relinquish_cookie(cell->cache, 0); #endif - key_put(cell->anonymous_key); kfree(cell); diff --git a/fs/afs/file.c b/fs/afs/file.c index a3901769a96..7a1d942ef68 100644 --- a/fs/afs/file.c +++ b/fs/afs/file.c @@ -23,6 +23,9 @@ static void afs_invalidatepage(struct page *page, unsigned long offset); static int afs_releasepage(struct page *page, gfp_t gfp_flags); static int afs_launder_page(struct page *page); +static int afs_readpages(struct file *filp, struct address_space *mapping, + struct list_head *pages, unsigned nr_pages); + const struct file_operations afs_file_operations = { .open = afs_open, .release = afs_release, @@ -46,6 +49,7 @@ const struct inode_operations afs_file_inode_operations = { const struct address_space_operations afs_fs_aops = { .readpage = afs_readpage, + .readpages = afs_readpages, .set_page_dirty = afs_set_page_dirty, .launder_page = afs_launder_page, .releasepage = afs_releasepage, @@ -101,37 +105,18 @@ int afs_release(struct inode *inode, struct file *file) /* * deal with notification that a page was read from the cache */ -#ifdef AFS_CACHING_SUPPORT -static void afs_readpage_read_complete(void *cookie_data, - struct page *page, - void *data, - int error) +static void afs_file_readpage_read_complete(struct page *page, + void *data, + int error) { - _enter("%p,%p,%p,%d", cookie_data, page, data, error); + _enter("%p,%p,%d", page, data, error); - if (error) - SetPageError(page); - else + /* if the read completes with an error, we just unlock the page and let + * the VM reissue the readpage */ + if (!error) SetPageUptodate(page); unlock_page(page); - } -#endif - -/* - * deal with notification that a page was written to the cache - */ -#ifdef AFS_CACHING_SUPPORT -static void afs_readpage_write_complete(void *cookie_data, - struct page *page, - void *data, - int error) -{ - _enter("%p,%p,%p,%d", cookie_data, page, data, error); - - unlock_page(page); -} -#endif /* * AFS read page from file, directory or symlink @@ -161,9 +146,9 @@ static int afs_readpage(struct file *file, struct page *page) if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) goto error; -#ifdef AFS_CACHING_SUPPORT /* is it cached? */ - ret = cachefs_read_or_alloc_page(vnode->cache, +#ifdef CONFIG_AFS_FSCACHE + ret = fscache_read_or_alloc_page(vnode->cache, page, afs_file_readpage_read_complete, NULL, @@ -171,20 +156,21 @@ static int afs_readpage(struct file *file, struct page *page) #else ret = -ENOBUFS; #endif - switch (ret) { - /* read BIO submitted and wb-journal entry found */ - case 1: - BUG(); // TODO - handle wb-journal match - /* read BIO submitted (page in cache) */ case 0: break; - /* no page available in cache */ - case -ENOBUFS: + /* page not yet cached */ case -ENODATA: + _debug("cache said ENODATA"); + goto go_on; + + /* page will not be cached */ + case -ENOBUFS: + _debug("cache said ENOBUFS"); default: + go_on: offset = page->index << PAGE_CACHE_SHIFT; len = min_t(size_t, i_size_read(inode) - offset, PAGE_SIZE); @@ -198,27 +184,25 @@ static int afs_readpage(struct file *file, struct page *page) set_bit(AFS_VNODE_DELETED, &vnode->flags); ret = -ESTALE; } -#ifdef AFS_CACHING_SUPPORT - cachefs_uncache_page(vnode->cache, page); + +#ifdef CONFIG_AFS_FSCACHE + fscache_uncache_page(vnode->cache, page); #endif + BUG_ON(PageFsCache(page)); goto error; } SetPageUptodate(page); -#ifdef AFS_CACHING_SUPPORT - if (cachefs_write_page(vnode->cache, - page, - afs_file_readpage_write_complete, - NULL, - GFP_KERNEL) != 0 - ) { - cachefs_uncache_page(vnode->cache, page); - unlock_page(page); + /* send the page to the cache */ +#ifdef CONFIG_AFS_FSCACHE + if (PageFsCache(page) && + fscache_write_page(vnode->cache, page, GFP_KERNEL) != 0) { + fscache_uncache_page(vnode->cache, page); + BUG_ON(PageFsCache(page)); } -#else - unlock_page(page); #endif + unlock_page(page); } _leave(" = 0"); @@ -232,34 +216,59 @@ error: } /* - * invalidate part or all of a page + * read a set of pages */ -static void afs_invalidatepage(struct page *page, unsigned long offset) +static int afs_readpages(struct file *file, struct address_space *mapping, + struct list_head *pages, unsigned nr_pages) { - int ret = 1; + struct afs_vnode *vnode; + int ret = 0; - _enter("{%lu},%lu", page->index, offset); + _enter(",{%lu},,%d", mapping->host->i_ino, nr_pages); - BUG_ON(!PageLocked(page)); + vnode = AFS_FS_I(mapping->host); + if (vnode->flags & AFS_VNODE_DELETED) { + _leave(" = -ESTALE"); + return -ESTALE; + } - if (PagePrivate(page)) { - /* We release buffers only if the entire page is being - * invalidated. - * The get_block cached value has been unconditionally - * invalidated, so real IO is not possible anymore. - */ - if (offset == 0) { - BUG_ON(!PageLocked(page)); - - ret = 0; - if (!PageWriteback(page)) - ret = page->mapping->a_ops->releasepage(page, - 0); - /* possibly should BUG_ON(!ret); - neilb */ - } + /* attempt to read as many of the pages as possible */ +#ifdef CONFIG_AFS_FSCACHE + ret = fscache_read_or_alloc_pages(vnode->cache, + mapping, + pages, + &nr_pages, + afs_file_readpage_read_complete, + NULL, + mapping_gfp_mask(mapping)); +#else + ret = -ENOBUFS; +#endif + + switch (ret) { + /* all pages are being read from the cache */ + case 0: + BUG_ON(!list_empty(pages)); + BUG_ON(nr_pages != 0); + _leave(" = 0 [reading all]"); + return 0; + + /* there were pages that couldn't be read from the cache */ + case -ENODATA: + case -ENOBUFS: + break; + + /* other error */ + default: + _leave(" = %d", ret); + return ret; } - _leave(" = %d", ret); + /* load the missing pages from the network */ + ret = read_cache_pages(mapping, pages, (void *) afs_readpage, file); + + _leave(" = %d [netting]", ret); + return ret; } /* @@ -273,25 +282,82 @@ static int afs_launder_page(struct page *page) } /* - * release a page and cleanup its private data + * invalidate part or all of a page + * - release a page and clean up its private data if offset is 0 (indicating + * the entire page) + */ +static void afs_invalidatepage(struct page *page, unsigned long offset) +{ + struct afs_writeback *wb = (struct afs_writeback *) page_private(page); + + _enter("{%lu},%lu", page->index, offset); + + BUG_ON(!PageLocked(page)); + + /* we clean up only if the entire page is being invalidated */ + if (offset == 0) { +#ifdef CONFIG_AFS_FSCACHE + if (PageFsCache(page)) { + struct afs_vnode *vnode = AFS_FS_I(page->mapping->host); + fscache_wait_on_page_write(vnode->cache, page); + fscache_uncache_page(vnode->cache, page); + ClearPageFsCache(page); + } +#endif + + if (PagePrivate(page)) { + if (wb && !PageWriteback(page)) { + set_page_private(page, 0); + afs_put_writeback(wb); + } + + if (!page_private(page)) + ClearPagePrivate(page); + } + } + + _leave(""); +} + +/* + * release a page and clean up its private state if it's not busy + * - return true if the page can now be released, false if not */ static int afs_releasepage(struct page *page, gfp_t gfp_flags) { + struct afs_writeback *wb = (struct afs_writeback *) page_private(page); struct afs_vnode *vnode = AFS_FS_I(page->mapping->host); - struct afs_writeback *wb; _enter("{{%x:%u}[%lu],%lx},%x", vnode->fid.vid, vnode->fid.vnode, page->index, page->flags, gfp_flags); + /* deny if page is being written to the cache and the caller hasn't + * elected to wait */ +#ifdef CONFIG_AFS_FSCACHE + if (PageFsCache(page)) { + if (fscache_check_page_write(vnode->cache, page)) { + if (!(gfp_flags & __GFP_WAIT)) { + _leave(" = F [cache busy]"); + return 0; + } + fscache_wait_on_page_write(vnode->cache, page); + } + + fscache_uncache_page(vnode->cache, page); + ClearPageFsCache(page); + } +#endif + if (PagePrivate(page)) { - wb = (struct afs_writeback *) page_private(page); - ASSERT(wb != NULL); - set_page_private(page, 0); + if (wb) { + set_page_private(page, 0); + afs_put_writeback(wb); + } ClearPagePrivate(page); - afs_put_writeback(wb); } - _leave(" = 0"); - return 0; + /* indicate that the page can be released */ + _leave(" = T"); + return 1; } diff --git a/fs/afs/inode.c b/fs/afs/inode.c index bb47217f6a1..c048f065875 100644 --- a/fs/afs/inode.c +++ b/fs/afs/inode.c @@ -61,6 +61,11 @@ static int afs_inode_map_status(struct afs_vnode *vnode, struct key *key) return -EBADMSG; } +#ifdef CONFIG_AFS_FSCACHE + if (vnode->status.size != inode->i_size) + fscache_attr_changed(vnode->cache); +#endif + inode->i_nlink = vnode->status.nlink; inode->i_uid = vnode->status.owner; inode->i_gid = 0; @@ -149,15 +154,6 @@ struct inode *afs_iget(struct super_block *sb, struct key *key, return inode; } -#ifdef AFS_CACHING_SUPPORT - /* set up caching before reading the status, as fetch-status reads the - * first page of symlinks to see if they're really mntpts */ - cachefs_acquire_cookie(vnode->volume->cache, - NULL, - vnode, - &vnode->cache); -#endif - if (!status) { /* it's a remotely extant inode */ set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags); @@ -183,6 +179,15 @@ struct inode *afs_iget(struct super_block *sb, struct key *key, } } + /* set up caching before mapping the status, as map-status reads the + * first page of symlinks to see if they're really mountpoints */ + inode->i_size = vnode->status.size; +#ifdef CONFIG_AFS_FSCACHE + vnode->cache = fscache_acquire_cookie(vnode->volume->cache, + &afs_vnode_cache_index_def, + vnode); +#endif + ret = afs_inode_map_status(vnode, key); if (ret < 0) goto bad_inode; @@ -196,6 +201,10 @@ struct inode *afs_iget(struct super_block *sb, struct key *key, /* failure */ bad_inode: +#ifdef CONFIG_AFS_FSCACHE + fscache_relinquish_cookie(vnode->cache, 0); + vnode->cache = NULL; +#endif iget_failed(inode); _leave(" = %d [bad]", ret); return ERR_PTR(ret); @@ -340,8 +349,8 @@ void afs_clear_inode(struct inode *inode) ASSERT(list_empty(&vnode->writebacks)); ASSERT(!vnode->cb_promised); -#ifdef AFS_CACHING_SUPPORT - cachefs_relinquish_cookie(vnode->cache, 0); +#ifdef CONFIG_AFS_FSCACHE + fscache_relinquish_cookie(vnode->cache, 0); vnode->cache = NULL; #endif diff --git a/fs/afs/internal.h b/fs/afs/internal.h index 67f259d99cd..106be66dafd 100644 --- a/fs/afs/internal.h +++ b/fs/afs/internal.h @@ -21,6 +21,7 @@ #include "afs.h" #include "afs_vl.h" +#include "cache.h" #define AFS_CELL_MAX_ADDRS 15 @@ -193,8 +194,8 @@ struct afs_cell { struct key *anonymous_key; /* anonymous user key for this cell */ struct list_head proc_link; /* /proc cell list link */ struct proc_dir_entry *proc_dir; /* /proc dir for this cell */ -#ifdef AFS_CACHING_SUPPORT - struct cachefs_cookie *cache; /* caching cookie */ +#ifdef CONFIG_AFS_FSCACHE + struct fscache_cookie *cache; /* caching cookie */ #endif /* server record management */ @@ -249,8 +250,8 @@ struct afs_vlocation { struct list_head grave; /* link in master graveyard list */ struct list_head update; /* link in master update list */ struct afs_cell *cell; /* cell to which volume belongs */ -#ifdef AFS_CACHING_SUPPORT - struct cachefs_cookie *cache; /* caching cookie */ +#ifdef CONFIG_AFS_FSCACHE + struct fscache_cookie *cache; /* caching cookie */ #endif struct afs_cache_vlocation vldb; /* volume information DB record */ struct afs_volume *vols[3]; /* volume access record pointer (index by type) */ @@ -302,8 +303,8 @@ struct afs_volume { atomic_t usage; struct afs_cell *cell; /* cell to which belongs (unrefd ptr) */ struct afs_vlocation *vlocation; /* volume location */ -#ifdef AFS_CACHING_SUPPORT - struct cachefs_cookie *cache; /* caching cookie */ +#ifdef CONFIG_AFS_FSCACHE + struct fscache_cookie *cache; /* caching cookie */ #endif afs_volid_t vid; /* volume ID */ afs_voltype_t type; /* type of volume */ @@ -333,8 +334,8 @@ struct afs_vnode { struct afs_server *server; /* server currently supplying this file */ struct afs_fid fid; /* the file identifier for this inode */ struct afs_file_status status; /* AFS status info for this file */ -#ifdef AFS_CACHING_SUPPORT - struct cachefs_cookie *cache; /* caching cookie */ +#ifdef CONFIG_AFS_FSCACHE + struct fscache_cookie *cache; /* caching cookie */ #endif struct afs_permits *permits; /* cache of permits so far obtained */ struct mutex permits_lock; /* lock for altering permits list */ @@ -427,6 +428,22 @@ struct afs_uuid { }; /*****************************************************************************/ +/* + * cache.c + */ +#ifdef CONFIG_AFS_FSCACHE +extern struct fscache_netfs afs_cache_netfs; +extern struct fscache_cookie_def afs_cell_cache_index_def; +extern struct fscache_cookie_def afs_vlocation_cache_index_def; +extern struct fscache_cookie_def afs_volume_cache_index_def; +extern struct fscache_cookie_def afs_vnode_cache_index_def; +#else +#define afs_cell_cache_index_def (*(struct fscache_cookie_def *) NULL) +#define afs_vlocation_cache_index_def (*(struct fscache_cookie_def *) NULL) +#define afs_volume_cache_index_def (*(struct fscache_cookie_def *) NULL) +#define afs_vnode_cache_index_def (*(struct fscache_cookie_def *) NULL) +#endif + /* * callback.c */ @@ -446,9 +463,6 @@ extern void afs_callback_update_kill(void); */ extern struct rw_semaphore afs_proc_cells_sem; extern struct list_head afs_proc_cells; -#ifdef AFS_CACHING_SUPPORT -extern struct cachefs_index_def afs_cache_cell_index_def; -#endif #define afs_get_cell(C) do { atomic_inc(&(C)->usage); } while(0) extern int afs_cell_init(char *); @@ -554,9 +568,6 @@ extern void afs_clear_inode(struct inode *); * main.c */ extern struct afs_uuid afs_uuid; -#ifdef AFS_CACHING_SUPPORT -extern struct cachefs_netfs afs_cache_netfs; -#endif /* * misc.c @@ -637,10 +648,6 @@ extern int afs_get_MAC_address(u8 *, size_t); /* * vlclient.c */ -#ifdef AFS_CACHING_SUPPORT -extern struct cachefs_index_def afs_vlocation_cache_index_def; -#endif - extern int afs_vl_get_entry_by_name(struct in_addr *, struct key *, const char *, struct afs_cache_vlocation *, const struct afs_wait_mode *); @@ -664,12 +671,6 @@ extern void afs_vlocation_purge(void); /* * vnode.c */ -#ifdef AFS_CACHING_SUPPORT -extern struct cachefs_index_def afs_vnode_cache_index_def; -#endif - -extern struct afs_timer_ops afs_vnode_cb_timed_out_ops; - static inline struct afs_vnode *AFS_FS_I(struct inode *inode) { return container_of(inode, struct afs_vnode, vfs_inode); @@ -711,10 +712,6 @@ extern int afs_vnode_release_lock(struct afs_vnode *, struct key *); /* * volume.c */ -#ifdef AFS_CACHING_SUPPORT -extern struct cachefs_index_def afs_volume_cache_index_def; -#endif - #define afs_get_volume(V) do { atomic_inc(&(V)->usage); } while(0) extern void afs_put_volume(struct afs_volume *); diff --git a/fs/afs/main.c b/fs/afs/main.c index 2d3e5d4fb9f..66d54d348c5 100644 --- a/fs/afs/main.c +++ b/fs/afs/main.c @@ -1,6 +1,6 @@ /* AFS client file system * - * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved. + * Copyright (C) 2002,5 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * * This program is free software; you can redistribute it and/or @@ -29,18 +29,6 @@ static char *rootcell; module_param(rootcell, charp, 0); MODULE_PARM_DESC(rootcell, "root AFS cell name and VL server IP addr list"); -#ifdef AFS_CACHING_SUPPORT -static struct cachefs_netfs_operations afs_cache_ops = { - .get_page_cookie = afs_cache_get_page_cookie, -}; - -struct cachefs_netfs afs_cache_netfs = { - .name = "afs", - .version = 0, - .ops = &afs_cache_ops, -}; -#endif - struct afs_uuid afs_uuid; /* @@ -104,10 +92,9 @@ static int __init afs_init(void) if (ret < 0) return ret; -#ifdef AFS_CACHING_SUPPORT +#ifdef CONFIG_AFS_FSCACHE /* we want to be able to cache */ - ret = cachefs_register_netfs(&afs_cache_netfs, - &afs_cache_cell_index_def); + ret = fscache_register_netfs(&afs_cache_netfs); if (ret < 0) goto error_cache; #endif @@ -142,8 +129,8 @@ error_fs: error_open_socket: error_vl_update_init: error_cell_init: -#ifdef AFS_CACHING_SUPPORT - cachefs_unregister_netfs(&afs_cache_netfs); +#ifdef CONFIG_AFS_FSCACHE + fscache_unregister_netfs(&afs_cache_netfs); error_cache: #endif afs_callback_update_kill(); @@ -175,8 +162,8 @@ static void __exit afs_exit(void) afs_vlocation_purge(); flush_scheduled_work(); afs_cell_purge(); -#ifdef AFS_CACHING_SUPPORT - cachefs_unregister_netfs(&afs_cache_netfs); +#ifdef CONFIG_AFS_FSCACHE + fscache_unregister_netfs(&afs_cache_netfs); #endif afs_proc_cleanup(); rcu_barrier(); diff --git a/fs/afs/mntpt.c b/fs/afs/mntpt.c index 78db4953a80..2b9e2d03a39 100644 --- a/fs/afs/mntpt.c +++ b/fs/afs/mntpt.c @@ -173,9 +173,9 @@ static struct vfsmount *afs_mntpt_do_automount(struct dentry *mntpt) if (PageError(page)) goto error; - buf = kmap(page); + buf = kmap_atomic(page, KM_USER0); memcpy(devname, buf, size); - kunmap(page); + kunmap_atomic(buf, KM_USER0); page_cache_release(page); page = NULL; diff --git a/fs/afs/vlocation.c b/fs/afs/vlocation.c index 849fc3160cb..ec2a7431e45 100644 --- a/fs/afs/vlocation.c +++ b/fs/afs/vlocation.c @@ -281,9 +281,8 @@ static void afs_vlocation_apply_update(struct afs_vlocation *vl, vl->vldb = *vldb; -#ifdef AFS_CACHING_SUPPORT - /* update volume entry in local cache */ - cachefs_update_cookie(vl->cache); +#ifdef CONFIG_AFS_FSCACHE + fscache_update_cookie(vl->cache); #endif } @@ -304,11 +303,9 @@ static int afs_vlocation_fill_in_record(struct afs_vlocation *vl, memset(&vldb, 0, sizeof(vldb)); /* see if we have an in-cache copy (will set vl->valid if there is) */ -#ifdef AFS_CACHING_SUPPORT - cachefs_acquire_cookie(cell->cache, - &afs_volume_cache_index_def, - vlocation, - &vl->cache); +#ifdef CONFIG_AFS_FSCACHE + vl->cache = fscache_acquire_cookie(vl->cell->cache, + &afs_vlocation_cache_index_def, vl); #endif if (vl->valid) { @@ -420,6 +417,11 @@ fill_in_record: spin_unlock(&vl->lock); wake_up(&vl->waitq); + /* update volume entry in local cache */ +#ifdef CONFIG_AFS_FSCACHE + fscache_update_cookie(vl->cache); +#endif + /* schedule for regular updates */ afs_vlocation_queue_for_updates(vl); goto success; @@ -465,7 +467,7 @@ found_in_memory: spin_unlock(&vl->lock); success: - _leave(" = %p",vl); + _leave(" = %p", vl); return vl; error_abandon: @@ -523,10 +525,9 @@ static void afs_vlocation_destroy(struct afs_vlocation *vl) { _enter("%p", vl); -#ifdef AFS_CACHING_SUPPORT - cachefs_relinquish_cookie(vl->cache, 0); +#ifdef CONFIG_AFS_FSCACHE + fscache_relinquish_cookie(vl->cache, 0); #endif - afs_put_cell(vl->cell); kfree(vl); } diff --git a/fs/afs/volume.c b/fs/afs/volume.c index 8bab0e3437f..a353e69e239 100644 --- a/fs/afs/volume.c +++ b/fs/afs/volume.c @@ -124,13 +124,11 @@ struct afs_volume *afs_volume_lookup(struct afs_mount_params *params) } /* attach the cache and volume location */ -#ifdef AFS_CACHING_SUPPORT - cachefs_acquire_cookie(vlocation->cache, - &afs_vnode_cache_index_def, - volume, - &volume->cache); +#ifdef CONFIG_AFS_FSCACHE + volume->cache = fscache_acquire_cookie(vlocation->cache, + &afs_volume_cache_index_def, + volume); #endif - afs_get_vlocation(vlocation); volume->vlocation = vlocation; @@ -194,8 +192,8 @@ void afs_put_volume(struct afs_volume *volume) up_write(&vlocation->cell->vl_sem); /* finish cleaning up the volume */ -#ifdef AFS_CACHING_SUPPORT - cachefs_relinquish_cookie(volume->cache, 0); +#ifdef CONFIG_AFS_FSCACHE + fscache_relinquish_cookie(volume->cache, 0); #endif afs_put_vlocation(vlocation); diff --git a/fs/afs/write.c b/fs/afs/write.c index 3fb36d43362..c2e7a7ff008 100644 --- a/fs/afs/write.c +++ b/fs/afs/write.c @@ -780,3 +780,24 @@ int afs_fsync(struct file *file, struct dentry *dentry, int datasync) _leave(" = %d", ret); return ret; } + +/* + * notification that a previously read-only page is about to become writable + * - if it returns an error, the caller will deliver a bus error signal + */ +int afs_page_mkwrite(struct vm_area_struct *vma, struct page *page) +{ + struct afs_vnode *vnode = AFS_FS_I(vma->vm_file->f_mapping->host); + + _enter("{{%x:%u}},{%lx}", + vnode->fid.vid, vnode->fid.vnode, page->index); + + /* wait for the page to be written to the cache before we allow it to + * be modified */ +#ifdef CONFIG_AFS_FSCACHE + fscache_wait_on_page_write(vnode->cache, page); +#endif + + _leave(" = 0"); + return 0; +} -- cgit v1.2.3-70-g09d2 From 6b9b3514aa188183e74049853be43380ad49314f Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:41 +0100 Subject: NFS: Add comment banners to some NFS functions Add comment banners to some NFS functions so that they can be modified by the NFS fscache patches for further information. Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Al Viro Tested-by: Daire Byrne --- fs/nfs/file.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) (limited to 'fs') diff --git a/fs/nfs/file.c b/fs/nfs/file.c index 0abf3f331f5..f5bc54dccec 100644 --- a/fs/nfs/file.c +++ b/fs/nfs/file.c @@ -409,6 +409,13 @@ static int nfs_write_end(struct file *file, struct address_space *mapping, return copied; } +/* + * Partially or wholly invalidate a page + * - Release the private state associated with a page if undergoing complete + * page invalidation + * - Called if either PG_private or PG_private_2 is set on the page + * - Caller holds page lock + */ static void nfs_invalidate_page(struct page *page, unsigned long offset) { dfprintk(PAGECACHE, "NFS: invalidate_page(%p, %lu)\n", page, offset); @@ -419,6 +426,12 @@ static void nfs_invalidate_page(struct page *page, unsigned long offset) nfs_wb_page_cancel(page->mapping->host, page); } +/* + * Attempt to release the private state associated with a page + * - Called if either PG_private or PG_private_2 is set on the page + * - Caller holds page lock + * - Return true (may release page) or false (may not) + */ static int nfs_release_page(struct page *page, gfp_t gfp) { dfprintk(PAGECACHE, "NFS: release_page(%p)\n", page); @@ -427,6 +440,14 @@ static int nfs_release_page(struct page *page, gfp_t gfp) return 0; } +/* + * Attempt to clear the private state associated with a page when an error + * occurs that requires the cached contents of an inode to be written back or + * destroyed + * - Called if either PG_private or PG_private_2 is set on the page + * - Caller holds page lock + * - Return 0 if successful, -error otherwise + */ static int nfs_launder_page(struct page *page) { struct inode *inode = page->mapping->host; @@ -451,6 +472,11 @@ const struct address_space_operations nfs_file_aops = { .launder_page = nfs_launder_page, }; +/* + * Notification that a PTE pointing to an NFS page is about to be made + * writable, implying that someone is about to modify the page through a + * shared-writable mapping + */ static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) { struct page *page = vmf->page; -- cgit v1.2.3-70-g09d2 From 3b9ce977b2f31b6c396b6fb620df9881a30fac9d Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:42 +0100 Subject: NFS: Permit local filesystem caching to be enabled for NFS Permit local filesystem caching to be enabled for NFS in the kernel configuration. Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Al Viro Tested-by: Daire Byrne --- fs/nfs/Kconfig | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'fs') diff --git a/fs/nfs/Kconfig b/fs/nfs/Kconfig index 36fe20d6eba..e67f3ec0773 100644 --- a/fs/nfs/Kconfig +++ b/fs/nfs/Kconfig @@ -84,3 +84,11 @@ config ROOT_NFS . Most people say N here. + +config NFS_FSCACHE + bool "Provide NFS client caching support (EXPERIMENTAL)" + depends on EXPERIMENTAL + depends on NFS_FS=m && FSCACHE || NFS_FS=y && FSCACHE=y + help + Say Y here if you want NFS data to be cached locally on disc through + the general filesystem cache manager -- cgit v1.2.3-70-g09d2 From 8ec442ae4c6577ed181682e534d4eef524e30b3c Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:42 +0100 Subject: NFS: Register NFS for caching and retrieve the top-level index Register NFS for caching and retrieve the top-level cache index object cookie. Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Al Viro Tested-by: Daire Byrne --- fs/nfs/Makefile | 1 + fs/nfs/fscache-index.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++ fs/nfs/fscache.h | 35 +++++++++++++++++++++++++++++++++++ fs/nfs/inode.c | 8 ++++++++ 4 files changed, 93 insertions(+) create mode 100644 fs/nfs/fscache-index.c create mode 100644 fs/nfs/fscache.h (limited to 'fs') diff --git a/fs/nfs/Makefile b/fs/nfs/Makefile index ac6170c594a..0e0bb6c17a8 100644 --- a/fs/nfs/Makefile +++ b/fs/nfs/Makefile @@ -15,3 +15,4 @@ nfs-$(CONFIG_NFS_V4) += nfs4proc.o nfs4xdr.o nfs4state.o nfs4renewd.o \ callback.o callback_xdr.o callback_proc.o \ nfs4namespace.o nfs-$(CONFIG_SYSCTL) += sysctl.o +nfs-$(CONFIG_NFS_FSCACHE) += fscache-index.o diff --git a/fs/nfs/fscache-index.c b/fs/nfs/fscache-index.c new file mode 100644 index 00000000000..6d5bb5c6904 --- /dev/null +++ b/fs/nfs/fscache-index.c @@ -0,0 +1,49 @@ +/* NFS FS-Cache index structure definition + * + * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#include +#include +#include +#include +#include +#include +#include + +#include "internal.h" +#include "fscache.h" + +#define NFSDBG_FACILITY NFSDBG_FSCACHE + +/* + * Define the NFS filesystem for FS-Cache. Upon registration FS-Cache sticks + * the cookie for the top-level index object for NFS into here. The top-level + * index can than have other cache objects inserted into it. + */ +struct fscache_netfs nfs_fscache_netfs = { + .name = "nfs", + .version = 0, +}; + +/* + * Register NFS for caching + */ +int nfs_fscache_register(void) +{ + return fscache_register_netfs(&nfs_fscache_netfs); +} + +/* + * Unregister NFS for caching + */ +void nfs_fscache_unregister(void) +{ + fscache_unregister_netfs(&nfs_fscache_netfs); +} diff --git a/fs/nfs/fscache.h b/fs/nfs/fscache.h new file mode 100644 index 00000000000..ccfcdc58066 --- /dev/null +++ b/fs/nfs/fscache.h @@ -0,0 +1,35 @@ +/* NFS filesystem cache interface definitions + * + * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#ifndef _NFS_FSCACHE_H +#define _NFS_FSCACHE_H + +#include +#include +#include +#include + +#ifdef CONFIG_NFS_FSCACHE + +/* + * fscache-index.c + */ +extern struct fscache_netfs nfs_fscache_netfs; + +extern int nfs_fscache_register(void); +extern void nfs_fscache_unregister(void); + +#else /* CONFIG_NFS_FSCACHE */ +static inline int nfs_fscache_register(void) { return 0; } +static inline void nfs_fscache_unregister(void) {} + +#endif /* CONFIG_NFS_FSCACHE */ +#endif /* _NFS_FSCACHE_H */ diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c index a834d1d850b..cd29f410e94 100644 --- a/fs/nfs/inode.c +++ b/fs/nfs/inode.c @@ -46,6 +46,7 @@ #include "delegation.h" #include "iostat.h" #include "internal.h" +#include "fscache.h" #define NFSDBG_FACILITY NFSDBG_VFS @@ -1436,6 +1437,10 @@ static int __init init_nfs_fs(void) { int err; + err = nfs_fscache_register(); + if (err < 0) + goto out7; + err = nfsiod_start(); if (err) goto out6; @@ -1488,6 +1493,8 @@ out4: out5: nfsiod_stop(); out6: + nfs_fscache_unregister(); +out7: return err; } @@ -1498,6 +1505,7 @@ static void __exit exit_nfs_fs(void) nfs_destroy_readpagecache(); nfs_destroy_inodecache(); nfs_destroy_nfspagecache(); + nfs_fscache_unregister(); #ifdef CONFIG_PROC_FS rpc_proc_unregister("nfs"); #endif -- cgit v1.2.3-70-g09d2 From 147272813e043fb44bd112527951da70c1e663de Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:42 +0100 Subject: NFS: Define and create server-level objects Define and create server-level cache index objects (as managed by nfs_client structs). Each server object is created in the NFS top-level index object and is itself an index into which superblock-level objects are inserted. Ideally there would be one superblock-level object per server, and the former would be folded into the latter; however, since the "nosharecache" option exists this isn't possible. The server object key is a sequence consisting of: (1) NFS version (2) Server address family (eg: AF_INET or AF_INET6) (3) Server port. (4) Server IP address. The key blob is of variable length, depending on the length of (4). The server object is given no coherency data to carry in the auxiliary data permitted by the cache. Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Al Viro Tested-by: Daire Byrne --- fs/nfs/Makefile | 2 +- fs/nfs/client.c | 5 ++++ fs/nfs/fscache-index.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++ fs/nfs/fscache.c | 52 +++++++++++++++++++++++++++++++++++++ fs/nfs/fscache.h | 10 ++++++++ include/linux/nfs_fs_sb.h | 4 +++ 6 files changed, 137 insertions(+), 1 deletion(-) create mode 100644 fs/nfs/fscache.c (limited to 'fs') diff --git a/fs/nfs/Makefile b/fs/nfs/Makefile index 0e0bb6c17a8..845159814de 100644 --- a/fs/nfs/Makefile +++ b/fs/nfs/Makefile @@ -15,4 +15,4 @@ nfs-$(CONFIG_NFS_V4) += nfs4proc.o nfs4xdr.o nfs4state.o nfs4renewd.o \ callback.o callback_xdr.o callback_proc.o \ nfs4namespace.o nfs-$(CONFIG_SYSCTL) += sysctl.o -nfs-$(CONFIG_NFS_FSCACHE) += fscache-index.o +nfs-$(CONFIG_NFS_FSCACHE) += fscache.o fscache-index.o diff --git a/fs/nfs/client.c b/fs/nfs/client.c index aba38017bde..aa04da8748a 100644 --- a/fs/nfs/client.c +++ b/fs/nfs/client.c @@ -45,6 +45,7 @@ #include "delegation.h" #include "iostat.h" #include "internal.h" +#include "fscache.h" #define NFSDBG_FACILITY NFSDBG_CLIENT @@ -154,6 +155,8 @@ static struct nfs_client *nfs_alloc_client(const struct nfs_client_initdata *cl_ if (!IS_ERR(cred)) clp->cl_machine_cred = cred; + nfs_fscache_get_client_cookie(clp); + return clp; error_3: @@ -187,6 +190,8 @@ static void nfs_free_client(struct nfs_client *clp) nfs4_shutdown_client(clp); + nfs_fscache_release_client_cookie(clp); + /* -EIO all pending I/O */ if (!IS_ERR(clp->cl_rpcclient)) rpc_shutdown_client(clp->cl_rpcclient); diff --git a/fs/nfs/fscache-index.c b/fs/nfs/fscache-index.c index 6d5bb5c6904..ff14b032459 100644 --- a/fs/nfs/fscache-index.c +++ b/fs/nfs/fscache-index.c @@ -47,3 +47,68 @@ void nfs_fscache_unregister(void) { fscache_unregister_netfs(&nfs_fscache_netfs); } + +/* + * Layout of the key for an NFS server cache object. + */ +struct nfs_server_key { + uint16_t nfsversion; /* NFS protocol version */ + uint16_t family; /* address family */ + uint16_t port; /* IP port */ + union { + struct in_addr ipv4_addr; /* IPv4 address */ + struct in6_addr ipv6_addr; /* IPv6 address */ + } addr[0]; +}; + +/* + * Generate a key to describe a server in the main NFS index + * - We return the length of the key, or 0 if we can't generate one + */ +static uint16_t nfs_server_get_key(const void *cookie_netfs_data, + void *buffer, uint16_t bufmax) +{ + const struct nfs_client *clp = cookie_netfs_data; + const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) &clp->cl_addr; + const struct sockaddr_in *sin = (struct sockaddr_in *) &clp->cl_addr; + struct nfs_server_key *key = buffer; + uint16_t len = sizeof(struct nfs_server_key); + + key->nfsversion = clp->rpc_ops->version; + key->family = clp->cl_addr.ss_family; + + memset(key, 0, len); + + switch (clp->cl_addr.ss_family) { + case AF_INET: + key->port = sin->sin_port; + key->addr[0].ipv4_addr = sin->sin_addr; + len += sizeof(key->addr[0].ipv4_addr); + break; + + case AF_INET6: + key->port = sin6->sin6_port; + key->addr[0].ipv6_addr = sin6->sin6_addr; + len += sizeof(key->addr[0].ipv6_addr); + break; + + default: + printk(KERN_WARNING "NFS: Unknown network family '%d'\n", + clp->cl_addr.ss_family); + len = 0; + break; + } + + return len; +} + +/* + * Define the server object for FS-Cache. This is used to describe a server + * object to fscache_acquire_cookie(). It is keyed by the NFS protocol and + * server address parameters. + */ +const struct fscache_cookie_def nfs_fscache_server_index_def = { + .name = "NFS.server", + .type = FSCACHE_COOKIE_TYPE_INDEX, + .get_key = nfs_server_get_key, +}; diff --git a/fs/nfs/fscache.c b/fs/nfs/fscache.c new file mode 100644 index 00000000000..c3f056f8947 --- /dev/null +++ b/fs/nfs/fscache.c @@ -0,0 +1,52 @@ +/* NFS filesystem cache interface + * + * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#include "internal.h" +#include "fscache.h" + +#define NFSDBG_FACILITY NFSDBG_FSCACHE + +/* + * Get the per-client index cookie for an NFS client if the appropriate mount + * flag was set + * - We always try and get an index cookie for the client, but get filehandle + * cookies on a per-superblock basis, depending on the mount flags + */ +void nfs_fscache_get_client_cookie(struct nfs_client *clp) +{ + /* create a cache index for looking up filehandles */ + clp->fscache = fscache_acquire_cookie(nfs_fscache_netfs.primary_index, + &nfs_fscache_server_index_def, + clp); + dfprintk(FSCACHE, "NFS: get client cookie (0x%p/0x%p)\n", + clp, clp->fscache); +} + +/* + * Dispose of a per-client cookie + */ +void nfs_fscache_release_client_cookie(struct nfs_client *clp) +{ + dfprintk(FSCACHE, "NFS: releasing client cookie (0x%p/0x%p)\n", + clp, clp->fscache); + + fscache_relinquish_cookie(clp->fscache, 0); + clp->fscache = NULL; +} diff --git a/fs/nfs/fscache.h b/fs/nfs/fscache.h index ccfcdc58066..1d864bedf15 100644 --- a/fs/nfs/fscache.h +++ b/fs/nfs/fscache.h @@ -23,13 +23,23 @@ * fscache-index.c */ extern struct fscache_netfs nfs_fscache_netfs; +extern const struct fscache_cookie_def nfs_fscache_server_index_def; extern int nfs_fscache_register(void); extern void nfs_fscache_unregister(void); +/* + * fscache.c + */ +extern void nfs_fscache_get_client_cookie(struct nfs_client *); +extern void nfs_fscache_release_client_cookie(struct nfs_client *); + #else /* CONFIG_NFS_FSCACHE */ static inline int nfs_fscache_register(void) { return 0; } static inline void nfs_fscache_unregister(void) {} +static inline void nfs_fscache_get_client_cookie(struct nfs_client *clp) {} +static inline void nfs_fscache_release_client_cookie(struct nfs_client *clp) {} + #endif /* CONFIG_NFS_FSCACHE */ #endif /* _NFS_FSCACHE_H */ diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h index a749f8564aa..0a374b9c509 100644 --- a/include/linux/nfs_fs_sb.h +++ b/include/linux/nfs_fs_sb.h @@ -64,6 +64,10 @@ struct nfs_client { char cl_ipaddr[48]; unsigned char cl_id_uniquifier; #endif + +#ifdef CONFIG_NFS_FSCACHE + struct fscache_cookie *fscache; /* client index cache cookie */ +#endif }; /* -- cgit v1.2.3-70-g09d2 From 08734048b380103f0412f58b84c2f76a2c8b599f Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:42 +0100 Subject: NFS: Define and create superblock-level objects Define and create superblock-level cache index objects (as managed by nfs_server structs). Each superblock object is created in a server level index object and is itself an index into which inode-level objects are inserted. Ideally there would be one superblock-level object per server, and the former would be folded into the latter; however, since the "nosharecache" option exists this isn't possible. The superblock object key is a sequence consisting of: (1) Certain superblock s_flags. (2) Various connection parameters that serve to distinguish superblocks for sget(). (3) The volume FSID. (4) The security flavour. (5) The uniquifier length. (6) The uniquifier text. This is normally an empty string, unless the fsc=xyz mount option was used to explicitly specify a uniquifier. The key blob is of variable length, depending on the length of (6). The superblock object is given no coherency data to carry in the auxiliary data permitted by the cache. It is assumed that the superblock is always coherent. This patch also adds uniquification handling such that two otherwise identical superblocks, at least one of which is marked "nosharecache", won't end up trying to share the on-disk cache. It will be possible to manually provide a uniquifier through a mount option with a later patch to avoid the error otherwise produced. Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Al Viro Tested-by: Daire Byrne --- fs/nfs/fscache-index.c | 34 ++++++++++++++ fs/nfs/fscache.c | 116 ++++++++++++++++++++++++++++++++++++++++++++++ fs/nfs/fscache.h | 49 ++++++++++++++++++++ fs/nfs/internal.h | 3 ++ fs/nfs/super.c | 9 +++- include/linux/nfs_fs_sb.h | 5 ++ 6 files changed, 214 insertions(+), 2 deletions(-) (limited to 'fs') diff --git a/fs/nfs/fscache-index.c b/fs/nfs/fscache-index.c index ff14b032459..a824050be80 100644 --- a/fs/nfs/fscache-index.c +++ b/fs/nfs/fscache-index.c @@ -112,3 +112,37 @@ const struct fscache_cookie_def nfs_fscache_server_index_def = { .type = FSCACHE_COOKIE_TYPE_INDEX, .get_key = nfs_server_get_key, }; + +/* + * Generate a key to describe a superblock key in the main NFS index + */ +static uint16_t nfs_super_get_key(const void *cookie_netfs_data, + void *buffer, uint16_t bufmax) +{ + const struct nfs_fscache_key *key; + const struct nfs_server *nfss = cookie_netfs_data; + uint16_t len; + + key = nfss->fscache_key; + len = sizeof(key->key) + key->key.uniq_len; + if (len > bufmax) { + len = 0; + } else { + memcpy(buffer, &key->key, sizeof(key->key)); + memcpy(buffer + sizeof(key->key), + key->key.uniquifier, key->key.uniq_len); + } + + return len; +} + +/* + * Define the superblock object for FS-Cache. This is used to describe a + * superblock object to fscache_acquire_cookie(). It is keyed by all the NFS + * parameters that might cause a separate superblock. + */ +const struct fscache_cookie_def nfs_fscache_super_index_def = { + .name = "NFS.super", + .type = FSCACHE_COOKIE_TYPE_INDEX, + .get_key = nfs_super_get_key, +}; diff --git a/fs/nfs/fscache.c b/fs/nfs/fscache.c index c3f056f8947..ab2de2c92b2 100644 --- a/fs/nfs/fscache.c +++ b/fs/nfs/fscache.c @@ -23,6 +23,9 @@ #define NFSDBG_FACILITY NFSDBG_FSCACHE +static struct rb_root nfs_fscache_keys = RB_ROOT; +static DEFINE_SPINLOCK(nfs_fscache_keys_lock); + /* * Get the per-client index cookie for an NFS client if the appropriate mount * flag was set @@ -50,3 +53,116 @@ void nfs_fscache_release_client_cookie(struct nfs_client *clp) fscache_relinquish_cookie(clp->fscache, 0); clp->fscache = NULL; } + +/* + * Get the cache cookie for an NFS superblock. We have to handle + * uniquification here because the cache doesn't do it for us. + */ +void nfs_fscache_get_super_cookie(struct super_block *sb, + struct nfs_parsed_mount_data *data) +{ + struct nfs_fscache_key *key, *xkey; + struct nfs_server *nfss = NFS_SB(sb); + struct rb_node **p, *parent; + const char *uniq = data->fscache_uniq ?: ""; + int diff, ulen; + + ulen = strlen(uniq); + key = kzalloc(sizeof(*key) + ulen, GFP_KERNEL); + if (!key) + return; + + key->nfs_client = nfss->nfs_client; + key->key.super.s_flags = sb->s_flags & NFS_MS_MASK; + key->key.nfs_server.flags = nfss->flags; + key->key.nfs_server.rsize = nfss->rsize; + key->key.nfs_server.wsize = nfss->wsize; + key->key.nfs_server.acregmin = nfss->acregmin; + key->key.nfs_server.acregmax = nfss->acregmax; + key->key.nfs_server.acdirmin = nfss->acdirmin; + key->key.nfs_server.acdirmax = nfss->acdirmax; + key->key.nfs_server.fsid = nfss->fsid; + key->key.rpc_auth.au_flavor = nfss->client->cl_auth->au_flavor; + + key->key.uniq_len = ulen; + memcpy(key->key.uniquifier, uniq, ulen); + + spin_lock(&nfs_fscache_keys_lock); + p = &nfs_fscache_keys.rb_node; + parent = NULL; + while (*p) { + parent = *p; + xkey = rb_entry(parent, struct nfs_fscache_key, node); + + if (key->nfs_client < xkey->nfs_client) + goto go_left; + if (key->nfs_client > xkey->nfs_client) + goto go_right; + + diff = memcmp(&key->key, &xkey->key, sizeof(key->key)); + if (diff < 0) + goto go_left; + if (diff > 0) + goto go_right; + + if (key->key.uniq_len == 0) + goto non_unique; + diff = memcmp(key->key.uniquifier, + xkey->key.uniquifier, + key->key.uniq_len); + if (diff < 0) + goto go_left; + if (diff > 0) + goto go_right; + goto non_unique; + + go_left: + p = &(*p)->rb_left; + continue; + go_right: + p = &(*p)->rb_right; + } + + rb_link_node(&key->node, parent, p); + rb_insert_color(&key->node, &nfs_fscache_keys); + spin_unlock(&nfs_fscache_keys_lock); + nfss->fscache_key = key; + + /* create a cache index for looking up filehandles */ + nfss->fscache = fscache_acquire_cookie(nfss->nfs_client->fscache, + &nfs_fscache_super_index_def, + nfss); + dfprintk(FSCACHE, "NFS: get superblock cookie (0x%p/0x%p)\n", + nfss, nfss->fscache); + return; + +non_unique: + spin_unlock(&nfs_fscache_keys_lock); + kfree(key); + nfss->fscache_key = NULL; + nfss->fscache = NULL; + printk(KERN_WARNING "NFS:" + " Cache request denied due to non-unique superblock keys\n"); +} + +/* + * release a per-superblock cookie + */ +void nfs_fscache_release_super_cookie(struct super_block *sb) +{ + struct nfs_server *nfss = NFS_SB(sb); + + dfprintk(FSCACHE, "NFS: releasing superblock cookie (0x%p/0x%p)\n", + nfss, nfss->fscache); + + fscache_relinquish_cookie(nfss->fscache, 0); + nfss->fscache = NULL; + + if (nfss->fscache_key) { + spin_lock(&nfs_fscache_keys_lock); + rb_erase(&nfss->fscache_key->node, &nfs_fscache_keys); + spin_unlock(&nfs_fscache_keys_lock); + kfree(nfss->fscache_key); + nfss->fscache_key = NULL; + } +} diff --git a/fs/nfs/fscache.h b/fs/nfs/fscache.h index 1d864bedf15..22b971e8b38 100644 --- a/fs/nfs/fscache.h +++ b/fs/nfs/fscache.h @@ -19,11 +19,49 @@ #ifdef CONFIG_NFS_FSCACHE +/* + * set of NFS FS-Cache objects that form a superblock key + */ +struct nfs_fscache_key { + struct rb_node node; + struct nfs_client *nfs_client; /* the server */ + + /* the elements of the unique key - as used by nfs_compare_super() and + * nfs_compare_mount_options() to distinguish superblocks */ + struct { + struct { + unsigned long s_flags; /* various flags + * (& NFS_MS_MASK) */ + } super; + + struct { + struct nfs_fsid fsid; + int flags; + unsigned int rsize; /* read size */ + unsigned int wsize; /* write size */ + unsigned int acregmin; /* attr cache timeouts */ + unsigned int acregmax; + unsigned int acdirmin; + unsigned int acdirmax; + } nfs_server; + + struct { + rpc_authflavor_t au_flavor; + } rpc_auth; + + /* uniquifier - can be used if nfs_server.flags includes + * NFS_MOUNT_UNSHARED */ + u8 uniq_len; + char uniquifier[0]; + } key; +}; + /* * fscache-index.c */ extern struct fscache_netfs nfs_fscache_netfs; extern const struct fscache_cookie_def nfs_fscache_server_index_def; +extern const struct fscache_cookie_def nfs_fscache_super_index_def; extern int nfs_fscache_register(void); extern void nfs_fscache_unregister(void); @@ -34,6 +72,10 @@ extern void nfs_fscache_unregister(void); extern void nfs_fscache_get_client_cookie(struct nfs_client *); extern void nfs_fscache_release_client_cookie(struct nfs_client *); +extern void nfs_fscache_get_super_cookie(struct super_block *, + struct nfs_parsed_mount_data *); +extern void nfs_fscache_release_super_cookie(struct super_block *); + #else /* CONFIG_NFS_FSCACHE */ static inline int nfs_fscache_register(void) { return 0; } static inline void nfs_fscache_unregister(void) {} @@ -41,5 +83,12 @@ static inline void nfs_fscache_unregister(void) {} static inline void nfs_fscache_get_client_cookie(struct nfs_client *clp) {} static inline void nfs_fscache_release_client_cookie(struct nfs_client *clp) {} +static inline void nfs_fscache_get_super_cookie( + struct super_block *sb, + struct nfs_parsed_mount_data *data) +{ +} +static inline void nfs_fscache_release_super_cookie(struct super_block *sb) {} + #endif /* CONFIG_NFS_FSCACHE */ #endif /* _NFS_FSCACHE_H */ diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h index 2041f68ff1c..013070000c3 100644 --- a/fs/nfs/internal.h +++ b/fs/nfs/internal.h @@ -5,6 +5,8 @@ #include #include +#define NFS_MS_MASK (MS_RDONLY|MS_NOSUID|MS_NODEV|MS_NOEXEC|MS_SYNCHRONOUS) + struct nfs_string; /* Maximum number of readahead requests @@ -41,6 +43,7 @@ struct nfs_parsed_mount_data { unsigned int auth_flavor_len; rpc_authflavor_t auth_flavors[1]; char *client_address; + char *fscache_uniq; struct { struct sockaddr_storage address; diff --git a/fs/nfs/super.c b/fs/nfs/super.c index 0942fcbbad3..87f65ae07f3 100644 --- a/fs/nfs/super.c +++ b/fs/nfs/super.c @@ -60,6 +60,7 @@ #include "delegation.h" #include "iostat.h" #include "internal.h" +#include "fscache.h" #define NFSDBG_FACILITY NFSDBG_VFS @@ -1870,8 +1871,6 @@ static void nfs_clone_super(struct super_block *sb, nfs_initialise_sb(sb); } -#define NFS_MS_MASK (MS_RDONLY|MS_NOSUID|MS_NODEV|MS_NOEXEC|MS_SYNCHRONOUS) - static int nfs_compare_mount_options(const struct super_block *s, const struct nfs_server *b, int flags) { const struct nfs_server *a = s->s_fs_info; @@ -2036,6 +2035,7 @@ static int nfs_get_sb(struct file_system_type *fs_type, if (!s->s_root) { /* initial superblock/root creation */ nfs_fill_super(s, data); + nfs_fscache_get_super_cookie(s, data); } mntroot = nfs_get_root(s, mntfh); @@ -2056,6 +2056,7 @@ static int nfs_get_sb(struct file_system_type *fs_type, out: kfree(data->nfs_server.hostname); kfree(data->mount_server.hostname); + kfree(data->fscache_uniq); security_free_mnt_opts(&data->lsm_opts); out_free_fh: kfree(mntfh); @@ -2083,6 +2084,7 @@ static void nfs_kill_super(struct super_block *s) bdi_unregister(&server->backing_dev_info); kill_anon_super(s); + nfs_fscache_release_super_cookie(s); nfs_free_server(server); } @@ -2390,6 +2392,7 @@ static int nfs4_get_sb(struct file_system_type *fs_type, if (!s->s_root) { /* initial superblock/root creation */ nfs4_fill_super(s); + nfs_fscache_get_super_cookie(s, data); } mntroot = nfs4_get_root(s, mntfh); @@ -2411,6 +2414,7 @@ out: kfree(data->client_address); kfree(data->nfs_server.export_path); kfree(data->nfs_server.hostname); + kfree(data->fscache_uniq); security_free_mnt_opts(&data->lsm_opts); out_free_fh: kfree(mntfh); @@ -2437,6 +2441,7 @@ static void nfs4_kill_super(struct super_block *sb) kill_anon_super(sb); nfs4_renewd_prepare_shutdown(server); + nfs_fscache_release_super_cookie(sb); nfs_free_server(server); } diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h index 0a374b9c509..6ad75948cbf 100644 --- a/include/linux/nfs_fs_sb.h +++ b/include/linux/nfs_fs_sb.h @@ -108,6 +108,11 @@ struct nfs_server { unsigned long mount_time; /* when this fs was mounted */ dev_t s_dev; /* superblock dev numbers */ +#ifdef CONFIG_NFS_FSCACHE + struct nfs_fscache_key *fscache_key; /* unique key for superblock */ + struct fscache_cookie *fscache; /* superblock cookie */ +#endif + #ifdef CONFIG_NFS_V4 u32 attr_bitmask[2];/* V4 bitmask representing the set of attributes supported on this -- cgit v1.2.3-70-g09d2 From 10329a5d48f5abc14a37d30b706e330f8598297a Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:43 +0100 Subject: NFS: Define and create inode-level cache objects Define and create inode-level cache data storage objects (as managed by nfs_inode structs). Each inode-level object is created in a superblock-level index object and is itself a data storage object into which pages from the inode are stored. The inode object key is the NFS file handle for the inode. The inode object is given coherency data to carry in the auxiliary data permitted by the cache. This is a sequence made up of: (1) i_mtime from the NFS inode. (2) i_ctime from the NFS inode. (3) i_size from the NFS inode. (4) change_attr from the NFSv4 attribute data. As the cache is a persistent cache, the auxiliary data is checked when a new NFS in-memory inode is set up that matches an already existing data storage object in the cache. If the coherency data is the same, the on-disk object is retained and used; if not, it is scrapped and a new one created. Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Al Viro Tested-by: Daire Byrne --- fs/nfs/fscache-index.c | 123 +++++++++++++++++++++++++++++++++++++++++++++++++ fs/nfs/fscache.h | 1 + 2 files changed, 124 insertions(+) (limited to 'fs') diff --git a/fs/nfs/fscache-index.c b/fs/nfs/fscache-index.c index a824050be80..7bc54acb7b0 100644 --- a/fs/nfs/fscache-index.c +++ b/fs/nfs/fscache-index.c @@ -146,3 +146,126 @@ const struct fscache_cookie_def nfs_fscache_super_index_def = { .type = FSCACHE_COOKIE_TYPE_INDEX, .get_key = nfs_super_get_key, }; + +/* + * Definition of the auxiliary data attached to NFS inode storage objects + * within the cache. + * + * The contents of this struct are recorded in the on-disk local cache in the + * auxiliary data attached to the data storage object backing an inode. This + * permits coherency to be managed when a new inode binds to an already extant + * cache object. + */ +struct nfs_fscache_inode_auxdata { + struct timespec mtime; + struct timespec ctime; + loff_t size; + u64 change_attr; +}; + +/* + * Generate a key to describe an NFS inode in an NFS server's index + */ +static uint16_t nfs_fscache_inode_get_key(const void *cookie_netfs_data, + void *buffer, uint16_t bufmax) +{ + const struct nfs_inode *nfsi = cookie_netfs_data; + uint16_t nsize; + + /* use the inode's NFS filehandle as the key */ + nsize = nfsi->fh.size; + memcpy(buffer, nfsi->fh.data, nsize); + return nsize; +} + +/* + * Get certain file attributes from the netfs data + * - This function can be absent for an index + * - Not permitted to return an error + * - The netfs data from the cookie being used as the source is presented + */ +static void nfs_fscache_inode_get_attr(const void *cookie_netfs_data, + uint64_t *size) +{ + const struct nfs_inode *nfsi = cookie_netfs_data; + + *size = nfsi->vfs_inode.i_size; +} + +/* + * Get the auxiliary data from netfs data + * - This function can be absent if the index carries no state data + * - Should store the auxiliary data in the buffer + * - Should return the amount of amount stored + * - Not permitted to return an error + * - The netfs data from the cookie being used as the source is presented + */ +static uint16_t nfs_fscache_inode_get_aux(const void *cookie_netfs_data, + void *buffer, uint16_t bufmax) +{ + struct nfs_fscache_inode_auxdata auxdata; + const struct nfs_inode *nfsi = cookie_netfs_data; + + memset(&auxdata, 0, sizeof(auxdata)); + auxdata.size = nfsi->vfs_inode.i_size; + auxdata.mtime = nfsi->vfs_inode.i_mtime; + auxdata.ctime = nfsi->vfs_inode.i_ctime; + + if (NFS_SERVER(&nfsi->vfs_inode)->nfs_client->rpc_ops->version == 4) + auxdata.change_attr = nfsi->change_attr; + + if (bufmax > sizeof(auxdata)) + bufmax = sizeof(auxdata); + + memcpy(buffer, &auxdata, bufmax); + return bufmax; +} + +/* + * Consult the netfs about the state of an object + * - This function can be absent if the index carries no state data + * - The netfs data from the cookie being used as the target is + * presented, as is the auxiliary data + */ +static +enum fscache_checkaux nfs_fscache_inode_check_aux(void *cookie_netfs_data, + const void *data, + uint16_t datalen) +{ + struct nfs_fscache_inode_auxdata auxdata; + struct nfs_inode *nfsi = cookie_netfs_data; + + if (datalen != sizeof(auxdata)) + return FSCACHE_CHECKAUX_OBSOLETE; + + memset(&auxdata, 0, sizeof(auxdata)); + auxdata.size = nfsi->vfs_inode.i_size; + auxdata.mtime = nfsi->vfs_inode.i_mtime; + auxdata.ctime = nfsi->vfs_inode.i_ctime; + + if (NFS_SERVER(&nfsi->vfs_inode)->nfs_client->rpc_ops->version == 4) + auxdata.change_attr = nfsi->change_attr; + + if (memcmp(data, &auxdata, datalen) != 0) + return FSCACHE_CHECKAUX_OBSOLETE; + + return FSCACHE_CHECKAUX_OKAY; +} + +/* + * Define the inode object for FS-Cache. This is used to describe an inode + * object to fscache_acquire_cookie(). It is keyed by the NFS file handle for + * an inode. + * + * Coherency is managed by comparing the copies of i_size, i_mtime and i_ctime + * held in the cache auxiliary data for the data storage object with those in + * the inode struct in memory. + */ +const struct fscache_cookie_def nfs_fscache_inode_object_def = { + .name = "NFS.fh", + .type = FSCACHE_COOKIE_TYPE_DATAFILE, + .get_key = nfs_fscache_inode_get_key, + .get_attr = nfs_fscache_inode_get_attr, + .get_aux = nfs_fscache_inode_get_aux, + .check_aux = nfs_fscache_inode_check_aux, +}; diff --git a/fs/nfs/fscache.h b/fs/nfs/fscache.h index 22b971e8b38..d21b5906ccf 100644 --- a/fs/nfs/fscache.h +++ b/fs/nfs/fscache.h @@ -62,6 +62,7 @@ struct nfs_fscache_key { extern struct fscache_netfs nfs_fscache_netfs; extern const struct fscache_cookie_def nfs_fscache_server_index_def; extern const struct fscache_cookie_def nfs_fscache_super_index_def; +extern const struct fscache_cookie_def nfs_fscache_inode_object_def; extern int nfs_fscache_register(void); extern void nfs_fscache_unregister(void); -- cgit v1.2.3-70-g09d2 From ef79c097bbe9724e13937271b3457df560e00370 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:43 +0100 Subject: NFS: Use local disk inode cache Bind data storage objects in the local cache to NFS inodes. Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Al Viro Tested-by: Daire Byrne --- fs/nfs/fscache.c | 162 +++++++++++++++++++++++++++++++++++++++++++++++++ fs/nfs/fscache.h | 13 ++++ fs/nfs/inode.c | 6 ++ include/linux/nfs_fs.h | 10 +++ 4 files changed, 191 insertions(+) (limited to 'fs') diff --git a/fs/nfs/fscache.c b/fs/nfs/fscache.c index ab2de2c92b2..e3816eb53fb 100644 --- a/fs/nfs/fscache.c +++ b/fs/nfs/fscache.c @@ -166,3 +166,165 @@ void nfs_fscache_release_super_cookie(struct super_block *sb) nfss->fscache_key = NULL; } } + +/* + * Initialise the per-inode cache cookie pointer for an NFS inode. + */ +void nfs_fscache_init_inode_cookie(struct inode *inode) +{ + NFS_I(inode)->fscache = NULL; + if (S_ISREG(inode->i_mode)) + set_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags); +} + +/* + * Get the per-inode cache cookie for an NFS inode. + */ +static void nfs_fscache_enable_inode_cookie(struct inode *inode) +{ + struct super_block *sb = inode->i_sb; + struct nfs_inode *nfsi = NFS_I(inode); + + if (nfsi->fscache || !NFS_FSCACHE(inode)) + return; + + if ((NFS_SB(sb)->options & NFS_OPTION_FSCACHE)) { + nfsi->fscache = fscache_acquire_cookie( + NFS_SB(sb)->fscache, + &nfs_fscache_inode_object_def, + nfsi); + + dfprintk(FSCACHE, "NFS: get FH cookie (0x%p/0x%p/0x%p)\n", + sb, nfsi, nfsi->fscache); + } +} + +/* + * Release a per-inode cookie. + */ +void nfs_fscache_release_inode_cookie(struct inode *inode) +{ + struct nfs_inode *nfsi = NFS_I(inode); + + dfprintk(FSCACHE, "NFS: clear cookie (0x%p/0x%p)\n", + nfsi, nfsi->fscache); + + fscache_relinquish_cookie(nfsi->fscache, 0); + nfsi->fscache = NULL; +} + +/* + * Retire a per-inode cookie, destroying the data attached to it. + */ +void nfs_fscache_zap_inode_cookie(struct inode *inode) +{ + struct nfs_inode *nfsi = NFS_I(inode); + + dfprintk(FSCACHE, "NFS: zapping cookie (0x%p/0x%p)\n", + nfsi, nfsi->fscache); + + fscache_relinquish_cookie(nfsi->fscache, 1); + nfsi->fscache = NULL; +} + +/* + * Turn off the cache with regard to a per-inode cookie if opened for writing, + * invalidating all the pages in the page cache relating to the associated + * inode to clear the per-page caching. + */ +static void nfs_fscache_disable_inode_cookie(struct inode *inode) +{ + clear_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags); + + if (NFS_I(inode)->fscache) { + dfprintk(FSCACHE, + "NFS: nfsi 0x%p turning cache off\n", NFS_I(inode)); + + /* Need to invalidate any mapped pages that were read in before + * turning off the cache. + */ + if (inode->i_mapping && inode->i_mapping->nrpages) + invalidate_inode_pages2(inode->i_mapping); + + nfs_fscache_zap_inode_cookie(inode); + } +} + +/* + * wait_on_bit() sleep function for uninterruptible waiting + */ +static int nfs_fscache_wait_bit(void *flags) +{ + schedule(); + return 0; +} + +/* + * Lock against someone else trying to also acquire or relinquish a cookie + */ +static inline void nfs_fscache_inode_lock(struct inode *inode) +{ + struct nfs_inode *nfsi = NFS_I(inode); + + while (test_and_set_bit(NFS_INO_FSCACHE_LOCK, &nfsi->flags)) + wait_on_bit(&nfsi->flags, NFS_INO_FSCACHE_LOCK, + nfs_fscache_wait_bit, TASK_UNINTERRUPTIBLE); +} + +/* + * Unlock cookie management lock + */ +static inline void nfs_fscache_inode_unlock(struct inode *inode) +{ + struct nfs_inode *nfsi = NFS_I(inode); + + smp_mb__before_clear_bit(); + clear_bit(NFS_INO_FSCACHE_LOCK, &nfsi->flags); + smp_mb__after_clear_bit(); + wake_up_bit(&nfsi->flags, NFS_INO_FSCACHE_LOCK); +} + +/* + * Decide if we should enable or disable local caching for this inode. + * - For now, with NFS, only regular files that are open read-only will be able + * to use the cache. + * - May be invoked multiple times in parallel by parallel nfs_open() functions. + */ +void nfs_fscache_set_inode_cookie(struct inode *inode, struct file *filp) +{ + if (NFS_FSCACHE(inode)) { + nfs_fscache_inode_lock(inode); + if ((filp->f_flags & O_ACCMODE) != O_RDONLY) + nfs_fscache_disable_inode_cookie(inode); + else + nfs_fscache_enable_inode_cookie(inode); + nfs_fscache_inode_unlock(inode); + } +} + +/* + * Replace a per-inode cookie due to revalidation detecting a file having + * changed on the server. + */ +void nfs_fscache_reset_inode_cookie(struct inode *inode) +{ + struct nfs_inode *nfsi = NFS_I(inode); + struct nfs_server *nfss = NFS_SERVER(inode); + struct fscache_cookie *old = nfsi->fscache; + + nfs_fscache_inode_lock(inode); + if (nfsi->fscache) { + /* retire the current fscache cache and get a new one */ + fscache_relinquish_cookie(nfsi->fscache, 1); + + nfsi->fscache = fscache_acquire_cookie( + nfss->nfs_client->fscache, + &nfs_fscache_inode_object_def, + nfsi); + + dfprintk(FSCACHE, + "NFS: revalidation new cookie (0x%p/0x%p/0x%p/0x%p)\n", + nfss, nfsi, old, nfsi->fscache); + } + nfs_fscache_inode_unlock(inode); +} diff --git a/fs/nfs/fscache.h b/fs/nfs/fscache.h index d21b5906ccf..8b4299a0ad6 100644 --- a/fs/nfs/fscache.h +++ b/fs/nfs/fscache.h @@ -77,6 +77,12 @@ extern void nfs_fscache_get_super_cookie(struct super_block *, struct nfs_parsed_mount_data *); extern void nfs_fscache_release_super_cookie(struct super_block *); +extern void nfs_fscache_init_inode_cookie(struct inode *); +extern void nfs_fscache_release_inode_cookie(struct inode *); +extern void nfs_fscache_zap_inode_cookie(struct inode *); +extern void nfs_fscache_set_inode_cookie(struct inode *, struct file *); +extern void nfs_fscache_reset_inode_cookie(struct inode *); + #else /* CONFIG_NFS_FSCACHE */ static inline int nfs_fscache_register(void) { return 0; } static inline void nfs_fscache_unregister(void) {} @@ -91,5 +97,12 @@ static inline void nfs_fscache_get_super_cookie( } static inline void nfs_fscache_release_super_cookie(struct super_block *sb) {} +static inline void nfs_fscache_init_inode_cookie(struct inode *inode) {} +static inline void nfs_fscache_release_inode_cookie(struct inode *inode) {} +static inline void nfs_fscache_zap_inode_cookie(struct inode *inode) {} +static inline void nfs_fscache_set_inode_cookie(struct inode *inode, + struct file *filp) {} +static inline void nfs_fscache_reset_inode_cookie(struct inode *inode) {} + #endif /* CONFIG_NFS_FSCACHE */ #endif /* _NFS_FSCACHE_H */ diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c index cd29f410e94..64f87194d39 100644 --- a/fs/nfs/inode.c +++ b/fs/nfs/inode.c @@ -122,6 +122,7 @@ void nfs_clear_inode(struct inode *inode) BUG_ON(!list_empty(&NFS_I(inode)->open_files)); nfs_zap_acl_cache(inode); nfs_access_zap_cache(inode); + nfs_fscache_release_inode_cookie(inode); } /** @@ -356,6 +357,8 @@ nfs_fhget(struct super_block *sb, struct nfs_fh *fh, struct nfs_fattr *fattr) nfsi->attrtimeo_timestamp = now; nfsi->access_cache = RB_ROOT; + nfs_fscache_init_inode_cookie(inode); + unlock_new_inode(inode); } else nfs_refresh_inode(inode, fattr); @@ -687,6 +690,7 @@ int nfs_open(struct inode *inode, struct file *filp) ctx->mode = filp->f_mode; nfs_file_set_open_context(filp, ctx); put_nfs_open_context(ctx); + nfs_fscache_set_inode_cookie(inode, filp); return 0; } @@ -787,6 +791,7 @@ static int nfs_invalidate_mapping_nolock(struct inode *inode, struct address_spa memset(nfsi->cookieverf, 0, sizeof(nfsi->cookieverf)); spin_unlock(&inode->i_lock); nfs_inc_stats(inode, NFSIOS_DATAINVALIDATE); + nfs_fscache_reset_inode_cookie(inode); dfprintk(PAGECACHE, "NFS: (%s/%Ld) data cache invalidated\n", inode->i_sb->s_id, (long long)NFS_FILEID(inode)); return 0; @@ -1031,6 +1036,7 @@ int nfs_refresh_inode(struct inode *inode, struct nfs_fattr *fattr) spin_lock(&inode->i_lock); status = nfs_refresh_inode_locked(inode, fattr); spin_unlock(&inode->i_lock); + return status; } diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h index fd3e7f9c6fd..8a99e79d5ea 100644 --- a/include/linux/nfs_fs.h +++ b/include/linux/nfs_fs.h @@ -185,6 +185,9 @@ struct nfs_inode { fmode_t delegation_state; struct rw_semaphore rwsem; #endif /* CONFIG_NFS_V4*/ +#ifdef CONFIG_NFS_FSCACHE + struct fscache_cookie *fscache; +#endif struct inode vfs_inode; }; @@ -207,6 +210,8 @@ struct nfs_inode { #define NFS_INO_ACL_LRU_SET (2) /* Inode is on the LRU list */ #define NFS_INO_MOUNTPOINT (3) /* inode is remote mountpoint */ #define NFS_INO_FLUSHING (4) /* inode is flushing out data */ +#define NFS_INO_FSCACHE (5) /* inode can be cached by FS-Cache */ +#define NFS_INO_FSCACHE_LOCK (6) /* FS-Cache cookie management lock */ static inline struct nfs_inode *NFS_I(const struct inode *inode) { @@ -260,6 +265,11 @@ static inline int NFS_STALE(const struct inode *inode) return test_bit(NFS_INO_STALE, &NFS_I(inode)->flags); } +static inline int NFS_FSCACHE(const struct inode *inode) +{ + return test_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags); +} + static inline __u64 NFS_FILEID(const struct inode *inode) { return NFS_I(inode)->fileid; -- cgit v1.2.3-70-g09d2 From d599064a1bca7bcbaabe54b94fa73ea86952cae3 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:43 +0100 Subject: NFS: Invalidate FsCache page flags when cache removed Invalidate the FsCache page flags on the pages belonging to an inode when the cache backing that NFS inode is removed. This allows a live cache to be withdrawn. Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Al Viro Tested-by: Daire Byrne --- fs/nfs/fscache-index.c | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) (limited to 'fs') diff --git a/fs/nfs/fscache-index.c b/fs/nfs/fscache-index.c index 7bc54acb7b0..a119b5691e7 100644 --- a/fs/nfs/fscache-index.c +++ b/fs/nfs/fscache-index.c @@ -252,6 +252,45 @@ enum fscache_checkaux nfs_fscache_inode_check_aux(void *cookie_netfs_data, return FSCACHE_CHECKAUX_OKAY; } +/* + * Indication from FS-Cache that the cookie is no longer cached + * - This function is called when the backing store currently caching a cookie + * is removed + * - The netfs should use this to clean up any markers indicating cached pages + * - This is mandatory for any object that may have data + */ +static void nfs_fscache_inode_now_uncached(void *cookie_netfs_data) +{ + struct nfs_inode *nfsi = cookie_netfs_data; + struct pagevec pvec; + pgoff_t first; + int loop, nr_pages; + + pagevec_init(&pvec, 0); + first = 0; + + dprintk("NFS: nfs_inode_now_uncached: nfs_inode 0x%p\n", nfsi); + + for (;;) { + /* grab a bunch of pages to unmark */ + nr_pages = pagevec_lookup(&pvec, + nfsi->vfs_inode.i_mapping, + first, + PAGEVEC_SIZE - pagevec_count(&pvec)); + if (!nr_pages) + break; + + for (loop = 0; loop < nr_pages; loop++) + ClearPageFsCache(pvec.pages[loop]); + + first = pvec.pages[nr_pages - 1]->index + 1; + + pvec.nr = nr_pages; + pagevec_release(&pvec); + cond_resched(); + } +} + /* * Define the inode object for FS-Cache. This is used to describe an inode * object to fscache_acquire_cookie(). It is keyed by the NFS file handle for @@ -268,4 +307,5 @@ const struct fscache_cookie_def nfs_fscache_inode_object_def = { .get_attr = nfs_fscache_inode_get_attr, .get_aux = nfs_fscache_inode_get_aux, .check_aux = nfs_fscache_inode_check_aux, + .now_uncached = nfs_fscache_inode_now_uncached, }; -- cgit v1.2.3-70-g09d2 From 6a51091d0775cdc4a923f2172c61925ad416aa32 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:43 +0100 Subject: NFS: Add some new I/O counters for FS-Cache doing things for NFS Add some new NFS I/O counters for FS-Cache doing things for NFS. A new line is emitted into /proc/pid/mountstats if caching is enabled that looks like: fsc: Where is the number of pages read successfully from the cache, is the number of failed page reads against the cache, is the number of successful page writes to the cache, is the number of failed page writes to the cache, and is the number of NFS pages that have been disconnected from the cache. Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Al Viro Tested-by: Daire Byrne --- fs/nfs/iostat.h | 18 ++++++++++++++++++ fs/nfs/super.c | 11 +++++++++++ include/linux/nfs_iostat.h | 12 ++++++++++++ 3 files changed, 41 insertions(+) (limited to 'fs') diff --git a/fs/nfs/iostat.h b/fs/nfs/iostat.h index a3695281003..a2ab2529b5c 100644 --- a/fs/nfs/iostat.h +++ b/fs/nfs/iostat.h @@ -16,6 +16,9 @@ struct nfs_iostats { unsigned long long bytes[__NFSIOS_BYTESMAX]; +#ifdef CONFIG_NFS_FSCACHE + unsigned long long fscache[__NFSIOS_FSCACHEMAX]; +#endif unsigned long events[__NFSIOS_COUNTSMAX]; } ____cacheline_aligned; @@ -57,6 +60,21 @@ static inline void nfs_add_stats(const struct inode *inode, nfs_add_server_stats(NFS_SERVER(inode), stat, addend); } +#ifdef CONFIG_NFS_FSCACHE +static inline void nfs_add_fscache_stats(struct inode *inode, + enum nfs_stat_fscachecounters stat, + unsigned long addend) +{ + struct nfs_iostats *iostats; + int cpu; + + cpu = get_cpu(); + iostats = per_cpu_ptr(NFS_SERVER(inode)->io_stats, cpu); + iostats->fscache[stat] += addend; + put_cpu_no_resched(); +} +#endif + static inline struct nfs_iostats *nfs_alloc_iostats(void) { return alloc_percpu(struct nfs_iostats); diff --git a/fs/nfs/super.c b/fs/nfs/super.c index 87f65ae07f3..b5fea776a0d 100644 --- a/fs/nfs/super.c +++ b/fs/nfs/super.c @@ -642,6 +642,10 @@ static int nfs_show_stats(struct seq_file *m, struct vfsmount *mnt) totals.events[i] += stats->events[i]; for (i = 0; i < __NFSIOS_BYTESMAX; i++) totals.bytes[i] += stats->bytes[i]; +#ifdef CONFIG_NFS_FSCACHE + for (i = 0; i < __NFSIOS_FSCACHEMAX; i++) + totals.fscache[i] += stats->fscache[i]; +#endif preempt_enable(); } @@ -652,6 +656,13 @@ static int nfs_show_stats(struct seq_file *m, struct vfsmount *mnt) seq_printf(m, "\n\tbytes:\t"); for (i = 0; i < __NFSIOS_BYTESMAX; i++) seq_printf(m, "%Lu ", totals.bytes[i]); +#ifdef CONFIG_NFS_FSCACHE + if (nfss->options & NFS_OPTION_FSCACHE) { + seq_printf(m, "\n\tfsc:\t"); + for (i = 0; i < __NFSIOS_FSCACHEMAX; i++) + seq_printf(m, "%Lu ", totals.bytes[i]); + } +#endif seq_printf(m, "\n"); rpc_print_iostats(m, nfss->client); diff --git a/include/linux/nfs_iostat.h b/include/linux/nfs_iostat.h index 1cb9a3fed2b..68b10f5f890 100644 --- a/include/linux/nfs_iostat.h +++ b/include/linux/nfs_iostat.h @@ -116,4 +116,16 @@ enum nfs_stat_eventcounters { __NFSIOS_COUNTSMAX, }; +/* + * NFS local caching servicing counters + */ +enum nfs_stat_fscachecounters { + NFSIOS_FSCACHE_PAGES_READ_OK, + NFSIOS_FSCACHE_PAGES_READ_FAIL, + NFSIOS_FSCACHE_PAGES_WRITTEN_OK, + NFSIOS_FSCACHE_PAGES_WRITTEN_FAIL, + NFSIOS_FSCACHE_PAGES_UNCACHED, + __NFSIOS_FSCACHEMAX, +}; + #endif /* _LINUX_NFS_IOSTAT */ -- cgit v1.2.3-70-g09d2 From 545db45f0fc0d4203b045047798ce156972a3056 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:44 +0100 Subject: NFS: FS-Cache page management FS-Cache page management for NFS. This includes hooking the releasing and invalidation of pages marked with PG_fscache (aka PG_private_2) and waiting for completion of the write-to-cache flag (PG_fscache_write aka PG_owner_priv_2). Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Al Viro Tested-by: Daire Byrne --- fs/nfs/file.c | 18 ++++++++++++++---- fs/nfs/fscache.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++ fs/nfs/fscache.h | 34 ++++++++++++++++++++++++++++++++++ 3 files changed, 101 insertions(+), 4 deletions(-) (limited to 'fs') diff --git a/fs/nfs/file.c b/fs/nfs/file.c index f5bc54dccec..3523b895eb4 100644 --- a/fs/nfs/file.c +++ b/fs/nfs/file.c @@ -35,6 +35,7 @@ #include "delegation.h" #include "internal.h" #include "iostat.h" +#include "fscache.h" #define NFSDBG_FACILITY NFSDBG_FILE @@ -413,7 +414,7 @@ static int nfs_write_end(struct file *file, struct address_space *mapping, * Partially or wholly invalidate a page * - Release the private state associated with a page if undergoing complete * page invalidation - * - Called if either PG_private or PG_private_2 is set on the page + * - Called if either PG_private or PG_fscache is set on the page * - Caller holds page lock */ static void nfs_invalidate_page(struct page *page, unsigned long offset) @@ -424,11 +425,13 @@ static void nfs_invalidate_page(struct page *page, unsigned long offset) return; /* Cancel any unstarted writes on this page */ nfs_wb_page_cancel(page->mapping->host, page); + + nfs_fscache_invalidate_page(page, page->mapping->host); } /* * Attempt to release the private state associated with a page - * - Called if either PG_private or PG_private_2 is set on the page + * - Called if either PG_private or PG_fscache is set on the page * - Caller holds page lock * - Return true (may release page) or false (may not) */ @@ -437,24 +440,28 @@ static int nfs_release_page(struct page *page, gfp_t gfp) dfprintk(PAGECACHE, "NFS: release_page(%p)\n", page); /* If PagePrivate() is set, then the page is not freeable */ - return 0; + if (PagePrivate(page)) + return 0; + return nfs_fscache_release_page(page, gfp); } /* * Attempt to clear the private state associated with a page when an error * occurs that requires the cached contents of an inode to be written back or * destroyed - * - Called if either PG_private or PG_private_2 is set on the page + * - Called if either PG_private or fscache is set on the page * - Caller holds page lock * - Return 0 if successful, -error otherwise */ static int nfs_launder_page(struct page *page) { struct inode *inode = page->mapping->host; + struct nfs_inode *nfsi = NFS_I(inode); dfprintk(PAGECACHE, "NFS: launder_page(%ld, %llu)\n", inode->i_ino, (long long)page_offset(page)); + nfs_fscache_wait_on_page_write(nfsi, page); return nfs_wb_page(inode, page); } @@ -491,6 +498,9 @@ static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) filp->f_mapping->host->i_ino, (long long)page_offset(page)); + /* make sure the cache has finished storing the page */ + nfs_fscache_wait_on_page_write(NFS_I(dentry->d_inode), page); + lock_page(page); mapping = page->mapping; if (mapping != dentry->d_inode->i_mapping) diff --git a/fs/nfs/fscache.c b/fs/nfs/fscache.c index e3816eb53fb..f673d35d8b8 100644 --- a/fs/nfs/fscache.c +++ b/fs/nfs/fscache.c @@ -19,6 +19,7 @@ #include #include "internal.h" +#include "iostat.h" #include "fscache.h" #define NFSDBG_FACILITY NFSDBG_FSCACHE @@ -328,3 +329,55 @@ void nfs_fscache_reset_inode_cookie(struct inode *inode) } nfs_fscache_inode_unlock(inode); } + +/* + * Release the caching state associated with a page, if the page isn't busy + * interacting with the cache. + * - Returns true (can release page) or false (page busy). + */ +int nfs_fscache_release_page(struct page *page, gfp_t gfp) +{ + struct nfs_inode *nfsi = NFS_I(page->mapping->host); + struct fscache_cookie *cookie = nfsi->fscache; + + BUG_ON(!cookie); + + if (fscache_check_page_write(cookie, page)) { + if (!(gfp & __GFP_WAIT)) + return 0; + fscache_wait_on_page_write(cookie, page); + } + + if (PageFsCache(page)) { + dfprintk(FSCACHE, "NFS: fscache releasepage (0x%p/0x%p/0x%p)\n", + cookie, page, nfsi); + + fscache_uncache_page(cookie, page); + nfs_add_fscache_stats(page->mapping->host, + NFSIOS_FSCACHE_PAGES_UNCACHED, 1); + } + + return 1; +} + +/* + * Release the caching state associated with a page if undergoing complete page + * invalidation. + */ +void __nfs_fscache_invalidate_page(struct page *page, struct inode *inode) +{ + struct nfs_inode *nfsi = NFS_I(inode); + struct fscache_cookie *cookie = nfsi->fscache; + + BUG_ON(!cookie); + + dfprintk(FSCACHE, "NFS: fscache invalidatepage (0x%p/0x%p/0x%p)\n", + cookie, page, nfsi); + + fscache_wait_on_page_write(cookie, page); + + BUG_ON(!PageLocked(page)); + fscache_uncache_page(cookie, page); + nfs_add_fscache_stats(page->mapping->host, + NFSIOS_FSCACHE_PAGES_UNCACHED, 1); +} diff --git a/fs/nfs/fscache.h b/fs/nfs/fscache.h index 8b4299a0ad6..e29613a8cbd 100644 --- a/fs/nfs/fscache.h +++ b/fs/nfs/fscache.h @@ -83,6 +83,31 @@ extern void nfs_fscache_zap_inode_cookie(struct inode *); extern void nfs_fscache_set_inode_cookie(struct inode *, struct file *); extern void nfs_fscache_reset_inode_cookie(struct inode *); +extern void __nfs_fscache_invalidate_page(struct page *, struct inode *); +extern int nfs_fscache_release_page(struct page *, gfp_t); + +/* + * wait for a page to complete writing to the cache + */ +static inline void nfs_fscache_wait_on_page_write(struct nfs_inode *nfsi, + struct page *page) +{ + if (PageFsCache(page)) + fscache_wait_on_page_write(nfsi->fscache, page); +} + +/* + * release the caching state associated with a page if undergoing complete page + * invalidation + */ +static inline void nfs_fscache_invalidate_page(struct page *page, + struct inode *inode) +{ + if (PageFsCache(page)) + __nfs_fscache_invalidate_page(page, inode); +} + + #else /* CONFIG_NFS_FSCACHE */ static inline int nfs_fscache_register(void) { return 0; } static inline void nfs_fscache_unregister(void) {} @@ -104,5 +129,14 @@ static inline void nfs_fscache_set_inode_cookie(struct inode *inode, struct file *filp) {} static inline void nfs_fscache_reset_inode_cookie(struct inode *inode) {} +static inline int nfs_fscache_release_page(struct page *page, gfp_t gfp) +{ + return 1; /* True: may release page */ +} +static inline void nfs_fscache_invalidate_page(struct page *page, + struct inode *inode) {} +static inline void nfs_fscache_wait_on_page_write(struct nfs_inode *nfsi, + struct page *page) {} + #endif /* CONFIG_NFS_FSCACHE */ #endif /* _NFS_FSCACHE_H */ -- cgit v1.2.3-70-g09d2 From 1fcdf534885b65e6d39780a5a89e9dfc5431cf68 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:44 +0100 Subject: NFS: Add read context retention for FS-Cache to call back with Add read context retention so that FS-Cache can call back into NFS when a read operation on the cache fails EIO rather than reading data. This permits NFS to then fetch the data from the server instead using the appropriate security context. Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Al Viro Tested-by: Daire Byrne --- fs/nfs/fscache-index.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) (limited to 'fs') diff --git a/fs/nfs/fscache-index.c b/fs/nfs/fscache-index.c index a119b5691e7..5b1006480bc 100644 --- a/fs/nfs/fscache-index.c +++ b/fs/nfs/fscache-index.c @@ -291,6 +291,30 @@ static void nfs_fscache_inode_now_uncached(void *cookie_netfs_data) } } +/* + * Get an extra reference on a read context. + * - This function can be absent if the completion function doesn't require a + * context. + * - The read context is passed back to NFS in the event that a data read on the + * cache fails with EIO - in which case the server must be contacted to + * retrieve the data, which requires the read context for security. + */ +static void nfs_fh_get_context(void *cookie_netfs_data, void *context) +{ + get_nfs_open_context(context); +} + +/* + * Release an extra reference on a read context. + * - This function can be absent if the completion function doesn't require a + * context. + */ +static void nfs_fh_put_context(void *cookie_netfs_data, void *context) +{ + if (context) + put_nfs_open_context(context); +} + /* * Define the inode object for FS-Cache. This is used to describe an inode * object to fscache_acquire_cookie(). It is keyed by the NFS file handle for @@ -308,4 +332,6 @@ const struct fscache_cookie_def nfs_fscache_inode_object_def = { .get_aux = nfs_fscache_inode_get_aux, .check_aux = nfs_fscache_inode_check_aux, .now_uncached = nfs_fscache_inode_now_uncached, + .get_context = nfs_fh_get_context, + .put_context = nfs_fh_put_context, }; -- cgit v1.2.3-70-g09d2 From f42b293d6d5259043a8944b556eeab427c695d57 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:44 +0100 Subject: NFS: nfs_readpage_async() needs to be accessible as a fallback for local caching nfs_readpage_async() needs to be non-static so that it can be used as a fallback for the local on-disk caching should an EIO crop up when reading the cache. Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Al Viro Tested-by: Daire Byrne --- fs/nfs/read.c | 4 ++-- include/linux/nfs_fs.h | 2 ++ 2 files changed, 4 insertions(+), 2 deletions(-) (limited to 'fs') diff --git a/fs/nfs/read.c b/fs/nfs/read.c index f856004bb7f..98b74009c9d 100644 --- a/fs/nfs/read.c +++ b/fs/nfs/read.c @@ -111,8 +111,8 @@ static void nfs_readpage_truncate_uninitialised_page(struct nfs_read_data *data) } } -static int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode, - struct page *page) +int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode, + struct page *page) { LIST_HEAD(one_request); struct nfs_page *new; diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h index 8a99e79d5ea..fdffb413b19 100644 --- a/include/linux/nfs_fs.h +++ b/include/linux/nfs_fs.h @@ -516,6 +516,8 @@ extern int nfs_readpages(struct file *, struct address_space *, struct list_head *, unsigned); extern int nfs_readpage_result(struct rpc_task *, struct nfs_read_data *); extern void nfs_readdata_release(void *data); +extern int nfs_readpage_async(struct nfs_open_context *, struct inode *, + struct page *); /* * Allocate nfs_read_data structures -- cgit v1.2.3-70-g09d2 From 9a9fc1c03315f1606596e55b4096d39e2079a041 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:44 +0100 Subject: NFS: Read pages from FS-Cache into an NFS inode Read pages from an FS-Cache data storage object representing an inode into an NFS inode. Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Al Viro Tested-by: Daire Byrne --- fs/nfs/fscache.c | 112 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ fs/nfs/fscache.h | 47 +++++++++++++++++++++++ fs/nfs/read.c | 18 +++++++++ 3 files changed, 177 insertions(+) (limited to 'fs') diff --git a/fs/nfs/fscache.c b/fs/nfs/fscache.c index f673d35d8b8..3a305665785 100644 --- a/fs/nfs/fscache.c +++ b/fs/nfs/fscache.c @@ -381,3 +381,115 @@ void __nfs_fscache_invalidate_page(struct page *page, struct inode *inode) nfs_add_fscache_stats(page->mapping->host, NFSIOS_FSCACHE_PAGES_UNCACHED, 1); } + +/* + * Handle completion of a page being read from the cache. + * - Called in process (keventd) context. + */ +static void nfs_readpage_from_fscache_complete(struct page *page, + void *context, + int error) +{ + dfprintk(FSCACHE, + "NFS: readpage_from_fscache_complete (0x%p/0x%p/%d)\n", + page, context, error); + + /* if the read completes with an error, we just unlock the page and let + * the VM reissue the readpage */ + if (!error) { + SetPageUptodate(page); + unlock_page(page); + } else { + error = nfs_readpage_async(context, page->mapping->host, page); + if (error) + unlock_page(page); + } +} + +/* + * Retrieve a page from fscache + */ +int __nfs_readpage_from_fscache(struct nfs_open_context *ctx, + struct inode *inode, struct page *page) +{ + int ret; + + dfprintk(FSCACHE, + "NFS: readpage_from_fscache(fsc:%p/p:%p(i:%lx f:%lx)/0x%p)\n", + NFS_I(inode)->fscache, page, page->index, page->flags, inode); + + ret = fscache_read_or_alloc_page(NFS_I(inode)->fscache, + page, + nfs_readpage_from_fscache_complete, + ctx, + GFP_KERNEL); + + switch (ret) { + case 0: /* read BIO submitted (page in fscache) */ + dfprintk(FSCACHE, + "NFS: readpage_from_fscache: BIO submitted\n"); + nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK, 1); + return ret; + + case -ENOBUFS: /* inode not in cache */ + case -ENODATA: /* page not in cache */ + nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL, 1); + dfprintk(FSCACHE, + "NFS: readpage_from_fscache %d\n", ret); + return 1; + + default: + dfprintk(FSCACHE, "NFS: readpage_from_fscache %d\n", ret); + nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL, 1); + } + return ret; +} + +/* + * Retrieve a set of pages from fscache + */ +int __nfs_readpages_from_fscache(struct nfs_open_context *ctx, + struct inode *inode, + struct address_space *mapping, + struct list_head *pages, + unsigned *nr_pages) +{ + int ret, npages = *nr_pages; + + dfprintk(FSCACHE, "NFS: nfs_getpages_from_fscache (0x%p/%u/0x%p)\n", + NFS_I(inode)->fscache, npages, inode); + + ret = fscache_read_or_alloc_pages(NFS_I(inode)->fscache, + mapping, pages, nr_pages, + nfs_readpage_from_fscache_complete, + ctx, + mapping_gfp_mask(mapping)); + if (*nr_pages < npages) + nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK, + npages); + if (*nr_pages > 0) + nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL, + *nr_pages); + + switch (ret) { + case 0: /* read submitted to the cache for all pages */ + BUG_ON(!list_empty(pages)); + BUG_ON(*nr_pages != 0); + dfprintk(FSCACHE, + "NFS: nfs_getpages_from_fscache: submitted\n"); + + return ret; + + case -ENOBUFS: /* some pages aren't cached and can't be */ + case -ENODATA: /* some pages aren't cached */ + dfprintk(FSCACHE, + "NFS: nfs_getpages_from_fscache: no page: %d\n", ret); + return 1; + + default: + dfprintk(FSCACHE, + "NFS: nfs_getpages_from_fscache: ret %d\n", ret); + } + + return ret; +} diff --git a/fs/nfs/fscache.h b/fs/nfs/fscache.h index e29613a8cbd..099349c171c 100644 --- a/fs/nfs/fscache.h +++ b/fs/nfs/fscache.h @@ -86,6 +86,12 @@ extern void nfs_fscache_reset_inode_cookie(struct inode *); extern void __nfs_fscache_invalidate_page(struct page *, struct inode *); extern int nfs_fscache_release_page(struct page *, gfp_t); +extern int __nfs_readpage_from_fscache(struct nfs_open_context *, + struct inode *, struct page *); +extern int __nfs_readpages_from_fscache(struct nfs_open_context *, + struct inode *, struct address_space *, + struct list_head *, unsigned *); + /* * wait for a page to complete writing to the cache */ @@ -107,6 +113,32 @@ static inline void nfs_fscache_invalidate_page(struct page *page, __nfs_fscache_invalidate_page(page, inode); } +/* + * Retrieve a page from an inode data storage object. + */ +static inline int nfs_readpage_from_fscache(struct nfs_open_context *ctx, + struct inode *inode, + struct page *page) +{ + if (NFS_I(inode)->fscache) + return __nfs_readpage_from_fscache(ctx, inode, page); + return -ENOBUFS; +} + +/* + * Retrieve a set of pages from an inode data storage object. + */ +static inline int nfs_readpages_from_fscache(struct nfs_open_context *ctx, + struct inode *inode, + struct address_space *mapping, + struct list_head *pages, + unsigned *nr_pages) +{ + if (NFS_I(inode)->fscache) + return __nfs_readpages_from_fscache(ctx, inode, mapping, pages, + nr_pages); + return -ENOBUFS; +} #else /* CONFIG_NFS_FSCACHE */ static inline int nfs_fscache_register(void) { return 0; } @@ -138,5 +170,20 @@ static inline void nfs_fscache_invalidate_page(struct page *page, static inline void nfs_fscache_wait_on_page_write(struct nfs_inode *nfsi, struct page *page) {} +static inline int nfs_readpage_from_fscache(struct nfs_open_context *ctx, + struct inode *inode, + struct page *page) +{ + return -ENOBUFS; +} +static inline int nfs_readpages_from_fscache(struct nfs_open_context *ctx, + struct inode *inode, + struct address_space *mapping, + struct list_head *pages, + unsigned *nr_pages) +{ + return -ENOBUFS; +} + #endif /* CONFIG_NFS_FSCACHE */ #endif /* _NFS_FSCACHE_H */ diff --git a/fs/nfs/read.c b/fs/nfs/read.c index 98b74009c9d..e18ba792872 100644 --- a/fs/nfs/read.c +++ b/fs/nfs/read.c @@ -24,6 +24,7 @@ #include "internal.h" #include "iostat.h" +#include "fscache.h" #define NFSDBG_FACILITY NFSDBG_PAGECACHE @@ -510,8 +511,15 @@ int nfs_readpage(struct file *file, struct page *page) } else ctx = get_nfs_open_context(nfs_file_open_context(file)); + if (!IS_SYNC(inode)) { + error = nfs_readpage_from_fscache(ctx, inode, page); + if (error == 0) + goto out; + } + error = nfs_readpage_async(ctx, inode, page); +out: put_nfs_open_context(ctx); return error; out_unlock: @@ -584,6 +592,15 @@ int nfs_readpages(struct file *filp, struct address_space *mapping, return -EBADF; } else desc.ctx = get_nfs_open_context(nfs_file_open_context(filp)); + + /* attempt to read as many of the pages as possible from the cache + * - this returns -ENOBUFS immediately if the cookie is negative + */ + ret = nfs_readpages_from_fscache(desc.ctx, inode, mapping, + pages, &nr_pages); + if (ret == 0) + goto read_complete; /* all pages were read */ + if (rsize < PAGE_CACHE_SIZE) nfs_pageio_init(&pgio, inode, nfs_pagein_multi, rsize, 0); else @@ -594,6 +611,7 @@ int nfs_readpages(struct file *filp, struct address_space *mapping, nfs_pageio_complete(&pgio); npages = (pgio.pg_bytes_written + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; nfs_add_stats(inode, NFSIOS_READPAGES, npages); +read_complete: put_nfs_open_context(desc.ctx); out: return ret; -- cgit v1.2.3-70-g09d2 From 7f8e05f60c87646e12c761fef61dd71a7e67112e Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:45 +0100 Subject: NFS: Store pages from an NFS inode into a local cache Store pages from an NFS inode into the cache data storage object associated with that inode. Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Al Viro Tested-by: Daire Byrne --- fs/nfs/fscache.c | 28 ++++++++++++++++++++++++++++ fs/nfs/fscache.h | 16 ++++++++++++++++ fs/nfs/read.c | 5 +++++ 3 files changed, 49 insertions(+) (limited to 'fs') diff --git a/fs/nfs/fscache.c b/fs/nfs/fscache.c index 3a305665785..379be678cb7 100644 --- a/fs/nfs/fscache.c +++ b/fs/nfs/fscache.c @@ -493,3 +493,31 @@ int __nfs_readpages_from_fscache(struct nfs_open_context *ctx, return ret; } + +/* + * Store a newly fetched page in fscache + * - PG_fscache must be set on the page + */ +void __nfs_readpage_to_fscache(struct inode *inode, struct page *page, int sync) +{ + int ret; + + dfprintk(FSCACHE, + "NFS: readpage_to_fscache(fsc:%p/p:%p(i:%lx f:%lx)/%d)\n", + NFS_I(inode)->fscache, page, page->index, page->flags, sync); + + ret = fscache_write_page(NFS_I(inode)->fscache, page, GFP_KERNEL); + dfprintk(FSCACHE, + "NFS: readpage_to_fscache: p:%p(i:%lu f:%lx) ret %d\n", + page, page->index, page->flags, ret); + + if (ret != 0) { + fscache_uncache_page(NFS_I(inode)->fscache, page); + nfs_add_fscache_stats(inode, + NFSIOS_FSCACHE_PAGES_WRITTEN_FAIL, 1); + nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_UNCACHED, 1); + } else { + nfs_add_fscache_stats(inode, + NFSIOS_FSCACHE_PAGES_WRITTEN_OK, 1); + } +} diff --git a/fs/nfs/fscache.h b/fs/nfs/fscache.h index 099349c171c..1ec3ebb0efc 100644 --- a/fs/nfs/fscache.h +++ b/fs/nfs/fscache.h @@ -91,6 +91,7 @@ extern int __nfs_readpage_from_fscache(struct nfs_open_context *, extern int __nfs_readpages_from_fscache(struct nfs_open_context *, struct inode *, struct address_space *, struct list_head *, unsigned *); +extern void __nfs_readpage_to_fscache(struct inode *, struct page *, int); /* * wait for a page to complete writing to the cache @@ -140,6 +141,19 @@ static inline int nfs_readpages_from_fscache(struct nfs_open_context *ctx, return -ENOBUFS; } +/* + * Store a page newly fetched from the server in an inode data storage object + * in the cache. + */ +static inline void nfs_readpage_to_fscache(struct inode *inode, + struct page *page, + int sync) +{ + if (PageFsCache(page)) + __nfs_readpage_to_fscache(inode, page, sync); +} + + #else /* CONFIG_NFS_FSCACHE */ static inline int nfs_fscache_register(void) { return 0; } static inline void nfs_fscache_unregister(void) {} @@ -184,6 +198,8 @@ static inline int nfs_readpages_from_fscache(struct nfs_open_context *ctx, { return -ENOBUFS; } +static inline void nfs_readpage_to_fscache(struct inode *inode, + struct page *page, int sync) {} #endif /* CONFIG_NFS_FSCACHE */ #endif /* _NFS_FSCACHE_H */ diff --git a/fs/nfs/read.c b/fs/nfs/read.c index e18ba792872..4ace3c50a8e 100644 --- a/fs/nfs/read.c +++ b/fs/nfs/read.c @@ -140,6 +140,11 @@ int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode, static void nfs_readpage_release(struct nfs_page *req) { + struct inode *d_inode = req->wb_context->path.dentry->d_inode; + + if (PageUptodate(req->wb_page)) + nfs_readpage_to_fscache(d_inode, req->wb_page, 0); + unlock_page(req->wb_page); dprintk("NFS: read done (%s/%Ld %d@%Ld)\n", -- cgit v1.2.3-70-g09d2 From 5d1acff159730770cbab68b19443518c92ab1000 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:47 +0100 Subject: NFS: Display local caching state Display the local caching state in /proc/fs/nfsfs/volumes. Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Al Viro Tested-by: Daire Byrne --- fs/nfs/client.c | 7 ++++--- fs/nfs/fscache.h | 15 +++++++++++++++ 2 files changed, 19 insertions(+), 3 deletions(-) (limited to 'fs') diff --git a/fs/nfs/client.c b/fs/nfs/client.c index aa04da8748a..726fe5a845b 100644 --- a/fs/nfs/client.c +++ b/fs/nfs/client.c @@ -1564,7 +1564,7 @@ static int nfs_volume_list_show(struct seq_file *m, void *v) /* display header on line 1 */ if (v == &nfs_volume_list) { - seq_puts(m, "NV SERVER PORT DEV FSID\n"); + seq_puts(m, "NV SERVER PORT DEV FSID FSC\n"); return 0; } /* display one transport per line on subsequent lines */ @@ -1578,12 +1578,13 @@ static int nfs_volume_list_show(struct seq_file *m, void *v) (unsigned long long) server->fsid.major, (unsigned long long) server->fsid.minor); - seq_printf(m, "v%u %s %s %-7s %-17s\n", + seq_printf(m, "v%u %s %s %-7s %-17s %s\n", clp->rpc_ops->version, rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_ADDR), rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_PORT), dev, - fsid); + fsid, + nfs_server_fscache_state(server)); return 0; } diff --git a/fs/nfs/fscache.h b/fs/nfs/fscache.h index 1ec3ebb0efc..6e809bb0ff0 100644 --- a/fs/nfs/fscache.h +++ b/fs/nfs/fscache.h @@ -153,6 +153,16 @@ static inline void nfs_readpage_to_fscache(struct inode *inode, __nfs_readpage_to_fscache(inode, page, sync); } +/* + * indicate the client caching state as readable text + */ +static inline const char *nfs_server_fscache_state(struct nfs_server *server) +{ + if (server->fscache && (server->options & NFS_OPTION_FSCACHE)) + return "yes"; + return "no "; +} + #else /* CONFIG_NFS_FSCACHE */ static inline int nfs_fscache_register(void) { return 0; } @@ -201,5 +211,10 @@ static inline int nfs_readpages_from_fscache(struct nfs_open_context *ctx, static inline void nfs_readpage_to_fscache(struct inode *inode, struct page *page, int sync) {} +static inline const char *nfs_server_fscache_state(struct nfs_server *server) +{ + return "no "; +} + #endif /* CONFIG_NFS_FSCACHE */ #endif /* _NFS_FSCACHE_H */ -- cgit v1.2.3-70-g09d2 From b797cac7487dee6bfddeb161631c1bbc54fa3cdb Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:48 +0100 Subject: NFS: Add mount options to enable local caching on NFS Add NFS mount options to allow the local caching support to be enabled. The attached patch makes it possible for the NFS filesystem to be told to make use of the network filesystem local caching service (FS-Cache). To be able to use this, a recent nfsutils package is required. There are three variant NFS mount options that can be added to a mount command to control caching for a mount. Only the last one specified takes effect: (*) Adding "fsc" will request caching. (*) Adding "fsc=" will request caching and also specify a uniquifier. (*) Adding "nofsc" will disable caching. For example: mount warthog:/ /a -o fsc The cache of a particular superblock (NFS FSID) will be shared between all mounts of that volume, provided they have the same connection parameters and are not marked 'nosharecache'. Where it is otherwise impossible to distinguish superblocks because all the parameters are identical, but the 'nosharecache' option is supplied, a uniquifying string must be supplied, else only the first mount will be permitted to use the cache. If there's a key collision, then the second mount will disable caching and give a warning into the kernel log. Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Al Viro Tested-by: Daire Byrne --- fs/nfs/client.c | 2 ++ fs/nfs/internal.h | 1 + fs/nfs/super.c | 25 +++++++++++++++++++++++++ 3 files changed, 28 insertions(+) (limited to 'fs') diff --git a/fs/nfs/client.c b/fs/nfs/client.c index 726fe5a845b..75c9cd2aa11 100644 --- a/fs/nfs/client.c +++ b/fs/nfs/client.c @@ -765,6 +765,7 @@ static int nfs_init_server(struct nfs_server *server, /* Initialise the client representation from the mount data */ server->flags = data->flags; + server->options = data->options; if (data->rsize) server->rsize = nfs_block_size(data->rsize, NULL); @@ -1153,6 +1154,7 @@ static int nfs4_init_server(struct nfs_server *server, /* Initialise the client representation from the mount data */ server->flags = data->flags; server->caps |= NFS_CAP_ATOMIC_OPEN; + server->options = data->options; /* Get a client record */ error = nfs4_set_client(server, diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h index 013070000c3..e4d6a8348ad 100644 --- a/fs/nfs/internal.h +++ b/fs/nfs/internal.h @@ -39,6 +39,7 @@ struct nfs_parsed_mount_data { int acregmin, acregmax, acdirmin, acdirmax; int namlen; + unsigned int options; unsigned int bsize; unsigned int auth_flavor_len; rpc_authflavor_t auth_flavors[1]; diff --git a/fs/nfs/super.c b/fs/nfs/super.c index b5fea776a0d..82eaadbff40 100644 --- a/fs/nfs/super.c +++ b/fs/nfs/super.c @@ -77,6 +77,7 @@ enum { Opt_rdirplus, Opt_nordirplus, Opt_sharecache, Opt_nosharecache, Opt_resvport, Opt_noresvport, + Opt_fscache, Opt_nofscache, /* Mount options that take integer arguments */ Opt_port, @@ -94,6 +95,7 @@ enum { Opt_sec, Opt_proto, Opt_mountproto, Opt_mounthost, Opt_addr, Opt_mountaddr, Opt_clientaddr, Opt_lookupcache, + Opt_fscache_uniq, /* Special mount options */ Opt_userspace, Opt_deprecated, Opt_sloppy, @@ -133,6 +135,9 @@ static const match_table_t nfs_mount_option_tokens = { { Opt_nosharecache, "nosharecache" }, { Opt_resvport, "resvport" }, { Opt_noresvport, "noresvport" }, + { Opt_fscache, "fsc" }, + { Opt_fscache_uniq, "fsc=%s" }, + { Opt_nofscache, "nofsc" }, { Opt_port, "port=%u" }, { Opt_rsize, "rsize=%u" }, @@ -564,6 +569,8 @@ static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss, if (clp->rpc_ops->version == 4) seq_printf(m, ",clientaddr=%s", clp->cl_ipaddr); #endif + if (nfss->options & NFS_OPTION_FSCACHE) + seq_printf(m, ",fsc"); } /* @@ -1056,6 +1063,24 @@ static int nfs_parse_mount_options(char *raw, case Opt_noresvport: mnt->flags |= NFS_MOUNT_NORESVPORT; break; + case Opt_fscache: + mnt->options |= NFS_OPTION_FSCACHE; + kfree(mnt->fscache_uniq); + mnt->fscache_uniq = NULL; + break; + case Opt_nofscache: + mnt->options &= ~NFS_OPTION_FSCACHE; + kfree(mnt->fscache_uniq); + mnt->fscache_uniq = NULL; + break; + case Opt_fscache_uniq: + string = match_strdup(args); + if (!string) + goto out_nomem; + kfree(mnt->fscache_uniq); + mnt->fscache_uniq = string; + mnt->options |= NFS_OPTION_FSCACHE; + break; /* * options that take numeric values -- cgit v1.2.3-70-g09d2