diff options
Diffstat (limited to 'drivers/md')
51 files changed, 11723 insertions, 104 deletions
diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig index f75a66e7d31..faa4741df6d 100644 --- a/drivers/md/Kconfig +++ b/drivers/md/Kconfig @@ -208,6 +208,16 @@ config DM_DEBUG If unsure, say N. +config DM_BUFIO + tristate + depends on BLK_DEV_DM && EXPERIMENTAL + ---help--- + This interface allows you to do buffered I/O on a device and acts + as a cache, holding recently-read blocks in memory and performing + delayed writes. + +source "drivers/md/persistent-data/Kconfig" + config DM_CRYPT tristate "Crypt target support" depends on BLK_DEV_DM @@ -233,6 +243,32 @@ config DM_SNAPSHOT ---help--- Allow volume managers to take writable snapshots of a device. +config DM_THIN_PROVISIONING + tristate "Thin provisioning target (EXPERIMENTAL)" + depends on BLK_DEV_DM && EXPERIMENTAL + select DM_PERSISTENT_DATA + ---help--- + Provides thin provisioning and snapshots that share a data store. + +config DM_DEBUG_BLOCK_STACK_TRACING + boolean "Keep stack trace of thin provisioning block lock holders" + depends on STACKTRACE_SUPPORT && DM_THIN_PROVISIONING + select STACKTRACE + ---help--- + Enable this for messages that may help debug problems with the + block manager locking used by thin provisioning. + + If unsure, say N. + +config DM_DEBUG_SPACE_MAPS + boolean "Extra validation for thin provisioning space maps" + depends on DM_THIN_PROVISIONING + ---help--- + Enable this for messages that may help debug problems with the + space maps used by thin provisioning. + + If unsure, say N. + config DM_MIRROR tristate "Mirror target" depends on BLK_DEV_DM diff --git a/drivers/md/Makefile b/drivers/md/Makefile index 448838b1f92..046860c7a16 100644 --- a/drivers/md/Makefile +++ b/drivers/md/Makefile @@ -10,6 +10,7 @@ dm-snapshot-y += dm-snap.o dm-exception-store.o dm-snap-transient.o \ dm-mirror-y += dm-raid1.o dm-log-userspace-y \ += dm-log-userspace-base.o dm-log-userspace-transfer.o +dm-thin-pool-y += dm-thin.o dm-thin-metadata.o md-mod-y += md.o bitmap.o raid456-y += raid5.o @@ -27,6 +28,7 @@ obj-$(CONFIG_MD_MULTIPATH) += multipath.o obj-$(CONFIG_MD_FAULTY) += faulty.o obj-$(CONFIG_BLK_DEV_MD) += md-mod.o obj-$(CONFIG_BLK_DEV_DM) += dm-mod.o +obj-$(CONFIG_DM_BUFIO) += dm-bufio.o obj-$(CONFIG_DM_CRYPT) += dm-crypt.o obj-$(CONFIG_DM_DELAY) += dm-delay.o obj-$(CONFIG_DM_FLAKEY) += dm-flakey.o @@ -34,10 +36,12 @@ obj-$(CONFIG_DM_MULTIPATH) += dm-multipath.o dm-round-robin.o obj-$(CONFIG_DM_MULTIPATH_QL) += dm-queue-length.o obj-$(CONFIG_DM_MULTIPATH_ST) += dm-service-time.o obj-$(CONFIG_DM_SNAPSHOT) += dm-snapshot.o +obj-$(CONFIG_DM_PERSISTENT_DATA) += persistent-data/ obj-$(CONFIG_DM_MIRROR) += dm-mirror.o dm-log.o dm-region-hash.o obj-$(CONFIG_DM_LOG_USERSPACE) += dm-log-userspace.o obj-$(CONFIG_DM_ZERO) += dm-zero.o obj-$(CONFIG_DM_RAID) += dm-raid.o +obj-$(CONFIG_DM_THIN_PROVISIONING) += dm-thin-pool.o ifeq ($(CONFIG_DM_UEVENT),y) dm-mod-objs += dm-uevent.o diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c new file mode 100644 index 00000000000..cb246667dd5 --- /dev/null +++ b/drivers/md/dm-bufio.c @@ -0,0 +1,1699 @@ +/* + * Copyright (C) 2009-2011 Red Hat, Inc. + * + * Author: Mikulas Patocka <mpatocka@redhat.com> + * + * This file is released under the GPL. + */ + +#include "dm-bufio.h" + +#include <linux/device-mapper.h> +#include <linux/dm-io.h> +#include <linux/slab.h> +#include <linux/vmalloc.h> +#include <linux/version.h> +#include <linux/shrinker.h> + +#define DM_MSG_PREFIX "bufio" + +/* + * Memory management policy: + * Limit the number of buffers to DM_BUFIO_MEMORY_PERCENT of main memory + * or DM_BUFIO_VMALLOC_PERCENT of vmalloc memory (whichever is lower). + * Always allocate at least DM_BUFIO_MIN_BUFFERS buffers. + * Start background writeback when there are DM_BUFIO_WRITEBACK_PERCENT + * dirty buffers. + */ +#define DM_BUFIO_MIN_BUFFERS 8 + +#define DM_BUFIO_MEMORY_PERCENT 2 +#define DM_BUFIO_VMALLOC_PERCENT 25 +#define DM_BUFIO_WRITEBACK_PERCENT 75 + +/* + * Check buffer ages in this interval (seconds) + */ +#define DM_BUFIO_WORK_TIMER_SECS 10 + +/* + * Free buffers when they are older than this (seconds) + */ +#define DM_BUFIO_DEFAULT_AGE_SECS 60 + +/* + * The number of bvec entries that are embedded directly in the buffer. + * If the chunk size is larger, dm-io is used to do the io. + */ +#define DM_BUFIO_INLINE_VECS 16 + +/* + * Buffer hash + */ +#define DM_BUFIO_HASH_BITS 20 +#define DM_BUFIO_HASH(block) \ + ((((block) >> DM_BUFIO_HASH_BITS) ^ (block)) & \ + ((1 << DM_BUFIO_HASH_BITS) - 1)) + +/* + * Don't try to use kmem_cache_alloc for blocks larger than this. + * For explanation, see alloc_buffer_data below. + */ +#define DM_BUFIO_BLOCK_SIZE_SLAB_LIMIT (PAGE_SIZE >> 1) +#define DM_BUFIO_BLOCK_SIZE_GFP_LIMIT (PAGE_SIZE << (MAX_ORDER - 1)) + +/* + * dm_buffer->list_mode + */ +#define LIST_CLEAN 0 +#define LIST_DIRTY 1 +#define LIST_SIZE 2 + +/* + * Linking of buffers: + * All buffers are linked to cache_hash with their hash_list field. + * + * Clean buffers that are not being written (B_WRITING not set) + * are linked to lru[LIST_CLEAN] with their lru_list field. + * + * Dirty and clean buffers that are being written are linked to + * lru[LIST_DIRTY] with their lru_list field. When the write + * finishes, the buffer cannot be relinked immediately (because we + * are in an interrupt context and relinking requires process + * context), so some clean-not-writing buffers can be held on + * dirty_lru too. They are later added to lru in the process + * context. + */ +struct dm_bufio_client { + struct mutex lock; + + struct list_head lru[LIST_SIZE]; + unsigned long n_buffers[LIST_SIZE]; + + struct block_device *bdev; + unsigned block_size; + unsigned char sectors_per_block_bits; + unsigned char pages_per_block_bits; + unsigned char blocks_per_page_bits; + unsigned aux_size; + void (*alloc_callback)(struct dm_buffer *); + void (*write_callback)(struct dm_buffer *); + + struct dm_io_client *dm_io; + + struct list_head reserved_buffers; + unsigned need_reserved_buffers; + + struct hlist_head *cache_hash; + wait_queue_head_t free_buffer_wait; + + int async_write_error; + + struct list_head client_list; + struct shrinker shrinker; +}; + +/* + * Buffer state bits. + */ +#define B_READING 0 +#define B_WRITING 1 +#define B_DIRTY 2 + +/* + * Describes how the block was allocated: + * kmem_cache_alloc(), __get_free_pages() or vmalloc(). + * See the comment at alloc_buffer_data. + */ +enum data_mode { + DATA_MODE_SLAB = 0, + DATA_MODE_GET_FREE_PAGES = 1, + DATA_MODE_VMALLOC = 2, + DATA_MODE_LIMIT = 3 +}; + +struct dm_buffer { + struct hlist_node hash_list; + struct list_head lru_list; + sector_t block; + void *data; + enum data_mode data_mode; + unsigned char list_mode; /* LIST_* */ + unsigned hold_count; + int read_error; + int write_error; + unsigned long state; + unsigned long last_accessed; + struct dm_bufio_client *c; + struct bio bio; + struct bio_vec bio_vec[DM_BUFIO_INLINE_VECS]; +}; + +/*----------------------------------------------------------------*/ + +static struct kmem_cache *dm_bufio_caches[PAGE_SHIFT - SECTOR_SHIFT]; +static char *dm_bufio_cache_names[PAGE_SHIFT - SECTOR_SHIFT]; + +static inline int dm_bufio_cache_index(struct dm_bufio_client *c) +{ + unsigned ret = c->blocks_per_page_bits - 1; + + BUG_ON(ret >= ARRAY_SIZE(dm_bufio_caches)); + + return ret; +} + +#define DM_BUFIO_CACHE(c) (dm_bufio_caches[dm_bufio_cache_index(c)]) +#define DM_BUFIO_CACHE_NAME(c) (dm_bufio_cache_names[dm_bufio_cache_index(c)]) + +#define dm_bufio_in_request() (!!current->bio_list) + +static void dm_bufio_lock(struct dm_bufio_client *c) +{ + mutex_lock_nested(&c->lock, dm_bufio_in_request()); +} + +static int dm_bufio_trylock(struct dm_bufio_client *c) +{ + return mutex_trylock(&c->lock); +} + +static void dm_bufio_unlock(struct dm_bufio_client *c) +{ + mutex_unlock(&c->lock); +} + +/* + * FIXME Move to sched.h? + */ +#ifdef CONFIG_PREEMPT_VOLUNTARY +# define dm_bufio_cond_resched() \ +do { \ + if (unlikely(need_resched())) \ + _cond_resched(); \ +} while (0) +#else +# define dm_bufio_cond_resched() do { } while (0) +#endif + +/*----------------------------------------------------------------*/ + +/* + * Default cache size: available memory divided by the ratio. + */ +static unsigned long dm_bufio_default_cache_size; + +/* + * Total cache size set by the user. + */ +static unsigned long dm_bufio_cache_size; + +/* + * A copy of dm_bufio_cache_size because dm_bufio_cache_size can change + * at any time. If it disagrees, the user has changed cache size. + */ +static unsigned long dm_bufio_cache_size_latch; + +static DEFINE_SPINLOCK(param_spinlock); + +/* + * Buffers are freed after this timeout + */ +static unsigned dm_bufio_max_age = DM_BUFIO_DEFAULT_AGE_SECS; + +static unsigned long dm_bufio_peak_allocated; +static unsigned long dm_bufio_allocated_kmem_cache; +static unsigned long dm_bufio_allocated_get_free_pages; +static unsigned long dm_bufio_allocated_vmalloc; +static unsigned long dm_bufio_current_allocated; + +/*----------------------------------------------------------------*/ + +/* + * Per-client cache: dm_bufio_cache_size / dm_bufio_client_count + */ +static unsigned long dm_bufio_cache_size_per_client; + +/* + * The current number of clients. + */ +static int dm_bufio_client_count; + +/* + * The list of all clients. + */ +static LIST_HEAD(dm_bufio_all_clients); + +/* + * This mutex protects dm_bufio_cache_size_latch, + * dm_bufio_cache_size_per_client and dm_bufio_client_count + */ +static DEFINE_MUTEX(dm_bufio_clients_lock); + +/*----------------------------------------------------------------*/ + +static void adjust_total_allocated(enum data_mode data_mode, long diff) +{ + static unsigned long * const class_ptr[DATA_MODE_LIMIT] = { + &dm_bufio_allocated_kmem_cache, + &dm_bufio_allocated_get_free_pages, + &dm_bufio_allocated_vmalloc, + }; + + spin_lock(¶m_spinlock); + + *class_ptr[data_mode] += diff; + + dm_bufio_current_allocated += diff; + + if (dm_bufio_current_allocated > dm_bufio_peak_allocated) + dm_bufio_peak_allocated = dm_bufio_current_allocated; + + spin_unlock(¶m_spinlock); +} + +/* + * Change the number of clients and recalculate per-client limit. + */ +static void __cache_size_refresh(void) +{ + BUG_ON(!mutex_is_locked(&dm_bufio_clients_lock)); + BUG_ON(dm_bufio_client_count < 0); + + dm_bufio_cache_size_latch = dm_bufio_cache_size; + + barrier(); + + /* + * Use default if set to 0 and report the actual cache size used. + */ + if (!dm_bufio_cache_size_latch) { + (void)cmpxchg(&dm_bufio_cache_size, 0, + dm_bufio_default_cache_size); + dm_bufio_cache_size_latch = dm_bufio_default_cache_size; + } + + dm_bufio_cache_size_per_client = dm_bufio_cache_size_latch / + (dm_bufio_client_count ? : 1); +} + +/* + * Allocating buffer data. + * + * Small buffers are allocated with kmem_cache, to use space optimally. + * + * For large buffers, we choose between get_free_pages and vmalloc. + * Each has advantages and disadvantages. + * + * __get_free_pages can randomly fail if the memory is fragmented. + * __vmalloc won't randomly fail, but vmalloc space is limited (it may be + * as low as 128M) so using it for caching is not appropriate. + * + * If the allocation may fail we use __get_free_pages. Memory fragmentation + * won't have a fatal effect here, but it just causes flushes of some other + * buffers and more I/O will be performed. Don't use __get_free_pages if it + * always fails (i.e. order >= MAX_ORDER). + * + * If the allocation shouldn't fail we use __vmalloc. This is only for the + * initial reserve allocation, so there's no risk of wasting all vmalloc + * space. + */ +static void *alloc_buffer_data(struct dm_bufio_client *c, gfp_t gfp_mask, + enum data_mode *data_mode) +{ + if (c->block_size <= DM_BUFIO_BLOCK_SIZE_SLAB_LIMIT) { + *data_mode = DATA_MODE_SLAB; + return kmem_cache_alloc(DM_BUFIO_CACHE(c), gfp_mask); + } + + if (c->block_size <= DM_BUFIO_BLOCK_SIZE_GFP_LIMIT && + gfp_mask & __GFP_NORETRY) { + *data_mode = DATA_MODE_GET_FREE_PAGES; + return (void *)__get_free_pages(gfp_mask, + c->pages_per_block_bits); + } + + *data_mode = DATA_MODE_VMALLOC; + return __vmalloc(c->block_size, gfp_mask, PAGE_KERNEL); +} + +/* + * Free buffer's data. + */ +static void free_buffer_data(struct dm_bufio_client *c, + void *data, enum data_mode data_mode) +{ + switch (data_mode) { + case DATA_MODE_SLAB: + kmem_cache_free(DM_BUFIO_CACHE(c), data); + break; + + case DATA_MODE_GET_FREE_PAGES: + free_pages((unsigned long)data, c->pages_per_block_bits); + break; + + case DATA_MODE_VMALLOC: + vfree(data); + break; + + default: + DMCRIT("dm_bufio_free_buffer_data: bad data mode: %d", + data_mode); + BUG(); + } +} + +/* + * Allocate buffer and its data. + */ +static struct dm_buffer *alloc_buffer(struct dm_bufio_client *c, gfp_t gfp_mask) +{ + struct dm_buffer *b = kmalloc(sizeof(struct dm_buffer) + c->aux_size, + gfp_mask); + + if (!b) + return NULL; + + b->c = c; + + b->data = alloc_buffer_data(c, gfp_mask, &b->data_mode); + if (!b->data) { + kfree(b); + return NULL; + } + + adjust_total_allocated(b->data_mode, (long)c->block_size); + + return b; +} + +/* + * Free buffer and its data. + */ +static void free_buffer(struct dm_buffer *b) +{ + struct dm_bufio_client *c = b->c; + + adjust_total_allocated(b->data_mode, -(long)c->block_size); + + free_buffer_data(c, b->data, b->data_mode); + kfree(b); +} + +/* + * Link buffer to the hash list and clean or dirty queue. + */ +static void __link_buffer(struct dm_buffer *b, sector_t block, int dirty) +{ + struct dm_bufio_client *c = b->c; + + c->n_buffers[dirty]++; + b->block = block; + b->list_mode = dirty; + list_add(&b->lru_list, &c->lru[dirty]); + hlist_add_head(&b->hash_list, &c->cache_hash[DM_BUFIO_HASH(block)]); + b->last_accessed = jiffies; +} + +/* + * Unlink buffer from the hash list and dirty or clean queue. + */ +static void __unlink_buffer(struct dm_buffer *b) +{ + struct dm_bufio_client *c = b->c; + + BUG_ON(!c->n_buffers[b->list_mode]); + + c->n_buffers[b->list_mode]--; + hlist_del(&b->hash_list); + list_del(&b->lru_list); +} + +/* + * Place the buffer to the head of dirty or clean LRU queue. + */ +static void __relink_lru(struct dm_buffer *b, int dirty) +{ + struct dm_bufio_client *c = b->c; + + BUG_ON(!c->n_buffers[b->list_mode]); + + c->n_buffers[b->list_mode]--; + c->n_buffers[dirty]++; + b->list_mode = dirty; + list_del(&b->lru_list); + list_add(&b->lru_list, &c->lru[dirty]); +} + +/*---------------------------------------------------------------- + * Submit I/O on the buffer. + * + * Bio interface is faster but it has some problems: + * the vector list is limited (increasing this limit increases + * memory-consumption per buffer, so it is not viable); + * + * the memory must be direct-mapped, not vmalloced; + * + * the I/O driver can reject requests spuriously if it thinks that + * the requests are too big for the device or if they cross a + * controller-defined memory boundary. + * + * If the buffer is small enough (up to DM_BUFIO_INLINE_VECS pages) and + * it is not vmalloced, try using the bio interface. + * + * If the buffer is big, if it is vmalloced or if the underlying device + * rejects the bio because it is too large, use dm-io layer to do the I/O. + * The dm-io layer splits the I/O into multiple requests, avoiding the above + * shortcomings. + *--------------------------------------------------------------*/ + +/* + * dm-io completion routine. It just calls b->bio.bi_end_io, pretending + * that the request was handled directly with bio interface. + */ +static void dmio_complete(unsigned long error, void *context) +{ + struct dm_buffer *b = context; + + b->bio.bi_end_io(&b->bio, error ? -EIO : 0); +} + +static void use_dmio(struct dm_buffer *b, int rw, sector_t block, + bio_end_io_t *end_io) +{ + int r; + struct dm_io_request io_req = { + .bi_rw = rw, + .notify.fn = dmio_complete, + .notify.context = b, + .client = b->c->dm_io, + }; + struct dm_io_region region = { + .bdev = b->c->bdev, + .sector = block << b->c->sectors_per_block_bits, + .count = b->c->block_size >> SECTOR_SHIFT, + }; + + if (b->data_mode != DATA_MODE_VMALLOC) { + io_req.mem.type = DM_IO_KMEM; + io_req.mem.ptr.addr = b->data; + } else { + io_req.mem.type = DM_IO_VMA; + io_req.mem.ptr.vma = b->data; + } + + b->bio.bi_end_io = end_io; + + r = dm_io(&io_req, 1, ®ion, NULL); + if (r) + end_io(&b->bio, r); +} + +static void use_inline_bio(struct dm_buffer *b, int rw, sector_t block, + bio_end_io_t *end_io) +{ + char *ptr; + int len; + + bio_init(&b->bio); + b->bio.bi_io_vec = b->bio_vec; + b->bio.bi_max_vecs = DM_BUFIO_INLINE_VECS; + b->bio.bi_sector = block << b->c->sectors_per_block_bits; + b->bio.bi_bdev = b->c->bdev; + b->bio.bi_end_io = end_io; + + /* + * We assume that if len >= PAGE_SIZE ptr is page-aligned. + * If len < PAGE_SIZE the buffer doesn't cross page boundary. + */ + ptr = b->data; + len = b->c->block_size; + + if (len >= PAGE_SIZE) + BUG_ON((unsigned long)ptr & (PAGE_SIZE - 1)); + else + BUG_ON((unsigned long)ptr & (len - 1)); + + do { + if (!bio_add_page(&b->bio, virt_to_page(ptr), + len < PAGE_SIZE ? len : PAGE_SIZE, + virt_to_phys(ptr) & (PAGE_SIZE - 1))) { + BUG_ON(b->c->block_size <= PAGE_SIZE); + use_dmio(b, rw, block, end_io); + return; + } + + len -= PAGE_SIZE; + ptr += PAGE_SIZE; + } while (len > 0); + + submit_bio(rw, &b->bio); +} + +static void submit_io(struct dm_buffer *b, int rw, sector_t block, + bio_end_io_t *end_io) +{ + if (rw == WRITE && b->c->write_callback) + b->c->write_callback(b); + + if (b->c->block_size <= DM_BUFIO_INLINE_VECS * PAGE_SIZE && + b->data_mode != DATA_MODE_VMALLOC) + use_inline_bio(b, rw, block, end_io); + else + use_dmio(b, rw, block, end_io); +} + +/*---------------------------------------------------------------- + * Writing dirty buffers + *--------------------------------------------------------------*/ + +/* + * The endio routine for write. + * + * Set the error, clear B_WRITING bit and wake anyone who was waiting on + * it. + */ +static void write_endio(struct bio *bio, int error) +{ + struct dm_buffer *b = container_of(bio, struct dm_buffer, bio); + + b->write_error = error; + if (error) { + struct dm_bufio_client *c = b->c; + (void)cmpxchg(&c->async_write_error, 0, error); + } + + BUG_ON(!test_bit(B_WRITING, &b->state)); + + smp_mb__before_clear_bit(); + clear_bit(B_WRITING, &b->state); + smp_mb__after_clear_bit(); + + wake_up_bit(&b->state, B_WRITING); +} + +/* + * This function is called when wait_on_bit is actually waiting. + */ +static int do_io_schedule(void *word) +{ + io_schedule(); + + return 0; +} + +/* + * Initiate a write on a dirty buffer, but don't wait for it. + * + * - If the buffer is not dirty, exit. + * - If there some previous write going on, wait for it to finish (we can't + * have two writes on the same buffer simultaneously). + * - Submit our write and don't wait on it. We set B_WRITING indicating + * that there is a write in progress. + */ +static void __write_dirty_buffer(struct dm_buffer *b) +{ + if (!test_bit(B_DIRTY, &b->state)) + return; + + clear_bit(B_DIRTY, &b->state); + wait_on_bit_lock(&b->state, B_WRITING, + do_io_schedule, TASK_UNINTERRUPTIBLE); + + submit_io(b, WRITE, b->block, write_endio); +} + +/* + * Wait until any activity on the buffer finishes. Possibly write the + * buffer if it is dirty. When this function finishes, there is no I/O + * running on the buffer and the buffer is not dirty. + */ +static void __make_buffer_clean(struct dm_buffer *b) +{ + BUG_ON(b->hold_count); + + if (!b->state) /* fast case */ + return; + + wait_on_bit(&b->state, B_READING, do_io_schedule, TASK_UNINTERRUPTIBLE); + __write_dirty_buffer(b); + wait_on_bit(&b->state, B_WRITING, do_io_schedule, TASK_UNINTERRUPTIBLE); +} + +/* + * Find some buffer that is not held by anybody, clean it, unlink it and + * return it. + */ +static struct dm_buffer *__get_unclaimed_buffer(struct dm_bufio_client *c) +{ + struct dm_buffer *b; + + list_for_each_entry_reverse(b, &c->lru[LIST_CLEAN], lru_list) { + BUG_ON(test_bit(B_WRITING, &b->state)); + BUG_ON(test_bit(B_DIRTY, &b->state)); + + if (!b->hold_count) { + __make_buffer_clean(b); + __unlink_buffer(b); + return b; + } + dm_bufio_cond_resched(); + } + + list_for_each_entry_reverse(b, &c->lru[LIST_DIRTY], lru_list) { + BUG_ON(test_bit(B_READING, &b->state)); + + if (!b->hold_count) { + __make_buffer_clean(b); + __unlink_buffer(b); + return b; + } + dm_bufio_cond_resched(); + } + + return NULL; +} + +/* + * Wait until some other threads free some buffer or release hold count on + * some buffer. + * + * This function is entered with c->lock held, drops it and regains it + * before exiting. + */ +static void __wait_for_free_buffer(struct dm_bufio_client *c) +{ + DECLARE_WAITQUEUE(wait, current); + + add_wait_queue(&c->free_buffer_wait, &wait); + set_task_state(current, TASK_UNINTERRUPTIBLE); + dm_bufio_unlock(c); + + io_schedule(); + + set_task_state(current, TASK_RUNNING); + remove_wait_queue(&c->free_buffer_wait, &wait); + + dm_bufio_lock(c); +} + +/* + * Allocate a new buffer. If the allocation is not possible, wait until + * some other thread frees a buffer. + * + * May drop the lock and regain it. + */ +static struct dm_buffer *__alloc_buffer_wait_no_callback(struct dm_bufio_client *c) +{ + struct dm_buffer *b; + + /* + * dm-bufio is resistant to allocation failures (it just keeps + * one buffer reserved in cases all the allocations fail). + * So set flags to not try too hard: + * GFP_NOIO: don't recurse into the I/O layer + * __GFP_NORETRY: don't retry and rather return failure + * __GFP_NOMEMALLOC: don't use emergency reserves + * __GFP_NOWARN: don't print a warning in case of failure + * + * For debugging, if we set the cache size to 1, no new buffers will + * be allocated. + */ + while (1) { + if (dm_bufio_cache_size_latch != 1) { + b = alloc_buffer(c, GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN); + if (b) + return b; + } + + if (!list_empty(&c->reserved_buffers)) { + b = list_entry(c->reserved_buffers.next, + struct dm_buffer, lru_list); + list_del(&b->lru_list); + c->need_reserved_buffers++; + + return b; + } + + b = __get_unclaimed_buffer(c); + if (b) + return b; + + __wait_for_free_buffer(c); + } +} + +static struct dm_buffer *__alloc_buffer_wait(struct dm_bufio_client *c) +{ + struct dm_buffer *b = __alloc_buffer_wait_no_callback(c); + + if (c->alloc_callback) + c->alloc_callback(b); + + return b; +} + +/* + * Free a buffer and wake other threads waiting for free buffers. + */ +static void __free_buffer_wake(struct dm_buffer *b) +{ + struct dm_bufio_client *c = b->c; + + if (!c->need_reserved_buffers) + free_buffer(b); + else { + list_add(&b->lru_list, &c->reserved_buffers); + c->need_reserved_buffers--; + } + + wake_up(&c->free_buffer_wait); +} + +static void __write_dirty_buffers_async(struct dm_bufio_client *c, int no_wait) +{ + struct dm_buffer *b, *tmp; + + list_for_each_entry_safe_reverse(b, tmp, &c->lru[LIST_DIRTY], lru_list) { + BUG_ON(test_bit(B_READING, &b->state)); + + if (!test_bit(B_DIRTY, &b->state) && + !test_bit(B_WRITING, &b->state)) { + __relink_lru(b, LIST_CLEAN); + continue; + } + + if (no_wait && test_bit(B_WRITING, &b->state)) + return; + + __write_dirty_buffer(b); + dm_bufio_cond_resched(); + } +} + +/* + * Get writeback threshold and buffer limit for a given client. + */ +static void __get_memory_limit(struct dm_bufio_client *c, + unsigned long *threshold_buffers, + unsigned long *limit_buffers) +{ + unsigned long buffers; + + if (dm_bufio_cache_size != dm_bufio_cache_size_latch) { + mutex_lock(&dm_bufio_clients_lock); + __cache_size_refresh(); + mutex_unlock(&dm_bufio_clients_lock); + } + + buffers = dm_bufio_cache_size_per_client >> + (c->sectors_per_block_bits + SECTOR_SHIFT); + + if (buffers < DM_BUFIO_MIN_BUFFERS) + buffers = DM_BUFIO_MIN_BUFFERS; + + *limit_buffers = buffers; + *threshold_buffers = buffers * DM_BUFIO_WRITEBACK_PERCENT / 100; +} + +/* + * Check if we're over watermark. + * If we are over threshold_buffers, start freeing buffers. + * If we're over "limit_buffers", block until we get under the limit. + */ +static void __check_watermark(struct dm_bufio_client *c) +{ + unsigned long threshold_buffers, limit_buffers; + + __get_memory_limit(c, &threshold_buffers, &limit_buffers); + + while (c->n_buffers[LIST_CLEAN] + c->n_buffers[LIST_DIRTY] > + limit_buffers) { + + struct dm_buffer *b = __get_unclaimed_buffer(c); + + if (!b) + return; + + __free_buffer_wake(b); + dm_bufio_cond_resched(); + } + + if (c->n_buffers[LIST_DIRTY] > threshold_buffers) + __write_dirty_buffers_async(c, 1); +} + +/* + * Find a buffer in the hash. + */ +static struct dm_buffer *__find(struct dm_bufio_client *c, sector_t block) +{ + struct dm_buffer *b; + struct hlist_node *hn; + + hlist_for_each_entry(b, hn, &c->cache_hash[DM_BUFIO_HASH(block)], + hash_list) { + dm_bufio_cond_resched(); + if (b->block == block) + return b; + } + + return NULL; +} + +/*---------------------------------------------------------------- + * Getting a buffer + *--------------------------------------------------------------*/ + +enum new_flag { + NF_FRESH = 0, + NF_READ = 1, + NF_GET = 2 +}; + +static struct dm_buffer *__bufio_new(struct dm_bufio_client *c, sector_t block, + enum new_flag nf, struct dm_buffer **bp, + int *need_submit) +{ + struct dm_buffer *b, *new_b = NULL; + + *need_submit = 0; + + b = __find(c, block); + if (b) { + b->hold_count++; + __relink_lru(b, test_bit(B_DIRTY, &b->state) || + test_bit(B_WRITING, &b->state)); + return b; + } + + if (nf == NF_GET) + return NULL; + + new_b = __alloc_buffer_wait(c); + + /* + * We've had a period where the mutex was unlocked, so need to + * recheck the hash table. + */ + b = __find(c, block); + if (b) { + __free_buffer_wake(new_b); + b->hold_count++; + __relink_lru(b, test_bit(B_DIRTY, &b->state) || + test_bit(B_WRITING, &b->state)); + return b; + } + + __check_watermark(c); + + b = new_b; + b->hold_count = 1; + b->read_error = 0; + b->write_error = 0; + __link_buffer(b, block, LIST_CLEAN); + + if (nf == NF_FRESH) { + b->state = 0; + return b; + } + + b->state = 1 << B_READING; + *need_submit = 1; + + return b; +} + +/* + * The endio routine for reading: set the error, clear the bit and wake up + * anyone waiting on the buffer. + */ +static void read_endio(struct bio *bio, int error) +{ + struct dm_buffer *b = container_of(bio, struct dm_buffer, bio); + + b->read_error = error; + + BUG_ON(!test_bit(B_READING, &b->state)); + + smp_mb__before_clear_bit(); + clear_bit(B_READING, &b->state); + smp_mb__after_clear_bit(); + + wake_up_bit(&b->state, B_READING); +} + +/* + * A common routine for dm_bufio_new and dm_bufio_read. Operation of these + * functions is similar except that dm_bufio_new doesn't read the + * buffer from the disk (assuming that the caller overwrites all the data + * and uses dm_bufio_mark_buffer_dirty to write new data back). + */ +static void *new_read(struct dm_bufio_client *c, sector_t block, + enum new_flag nf, struct dm_buffer **bp) +{ + int need_submit; + struct dm_buffer *b; + + dm_bufio_lock(c); + b = __bufio_new(c, block, nf, bp, &need_submit); + dm_bufio_unlock(c); + + if (!b || IS_ERR(b)) + return b; + + if (need_submit) + submit_io(b, READ, b->block, read_endio); + + wait_on_bit(&b->state, B_READING, do_io_schedule, TASK_UNINTERRUPTIBLE); + + if (b->read_error) { + int error = b->read_error; + + dm_bufio_release(b); + + return ERR_PTR(error); + } + + *bp = b; + + return b->data; +} + +void *dm_bufio_get(struct dm_bufio_client *c, sector_t block, + struct dm_buffer **bp) +{ + return new_read(c, block, NF_GET, bp); +} +EXPORT_SYMBOL_GPL(dm_bufio_get); + +void *dm_bufio_read(struct dm_bufio_client *c, sector_t block, + struct dm_buffer **bp) +{ + BUG_ON(dm_bufio_in_request()); + + return new_read(c, block, NF_READ, bp); +} +EXPORT_SYMBOL_GPL(dm_bufio_read); + +void *dm_bufio_new(struct dm_bufio_client *c, sector_t block, + struct dm_buffer **bp) +{ + BUG_ON(dm_bufio_in_request()); + + return new_read(c, block, NF_FRESH, bp); +} +EXPORT_SYMBOL_GPL(dm_bufio_new); + +void dm_bufio_release(struct dm_buffer *b) +{ + struct dm_bufio_client *c = b->c; + + dm_bufio_lock(c); + + BUG_ON(test_bit(B_READING, &b->state)); + BUG_ON(!b->hold_count); + + b->hold_count--; + if (!b->hold_count) { + wake_up(&c->free_buffer_wait); + + /* + * If there were errors on the buffer, and the buffer is not + * to be written, free the buffer. There is no point in caching + * invalid buffer. + */ + if ((b->read_error || b->write_error) && + !test_bit(B_WRITING, &b->state) && + !test_bit(B_DIRTY, &b->state)) { + __unlink_buffer(b); + __free_buffer_wake(b); + } + } + + dm_bufio_unlock(c); +} +EXPORT_SYMBOL_GPL(dm_bufio_release); + +void dm_bufio_mark_buffer_dirty(struct dm_buffer *b) +{ + struct dm_bufio_client *c = b->c; + + dm_bufio_lock(c); + + if (!test_and_set_bit(B_DIRTY, &b->state)) + __relink_lru(b, LIST_DIRTY); + + dm_bufio_unlock(c); +} +EXPORT_SYMBOL_GPL(dm_bufio_mark_buffer_dirty); + +void dm_bufio_write_dirty_buffers_async(struct dm_bufio_client *c) +{ + BUG_ON(dm_bufio_in_request()); + + dm_bufio_lock(c); + __write_dirty_buffers_async(c, 0); + dm_bufio_unlock(c); +} +EXPORT_SYMBOL_GPL(dm_bufio_write_dirty_buffers_async); + +/* + * For performance, it is essential that the buffers are written asynchronously + * and simultaneously (so that the block layer can merge the writes) and then + * waited upon. + * + * Finally, we flush hardware disk cache. + */ +int dm_bufio_write_dirty_buffers(struct dm_bufio_client *c) +{ + int a, f; + unsigned long buffers_processed = 0; + struct dm_buffer *b, *tmp; + + dm_bufio_lock(c); + __write_dirty_buffers_async(c, 0); + +again: + list_for_each_entry_safe_reverse(b, tmp, &c->lru[LIST_DIRTY], lru_list) { + int dropped_lock = 0; + + if (buffers_processed < c->n_buffers[LIST_DIRTY]) + buffers_processed++; + + BUG_ON(test_bit(B_READING, &b->state)); + + if (test_bit(B_WRITING, &b->state)) { + if (buffers_processed < c->n_buffers[LIST_DIRTY]) { + dropped_lock = 1; + b->hold_count++; + dm_bufio_unlock(c); + wait_on_bit(&b->state, B_WRITING, + do_io_schedule, + TASK_UNINTERRUPTIBLE); + dm_bufio_lock(c); + b->hold_count--; + } else + wait_on_bit(&b->state, B_WRITING, + do_io_schedule, + TASK_UNINTERRUPTIBLE); + } + + if (!test_bit(B_DIRTY, &b->state) && + !test_bit(B_WRITING, &b->state)) + __relink_lru(b, LIST_CLEAN); + + dm_bufio_cond_resched(); + + /* + * If we dropped the lock, the list is no longer consistent, + * so we must restart the search. + * + * In the most common case, the buffer just processed is + * relinked to the clean list, so we won't loop scanning the + * same buffer again and again. + * + * This may livelock if there is another thread simultaneously + * dirtying buffers, so we count the number of buffers walked + * and if it exceeds the total number of buffers, it means that + * someone is doing some writes simultaneously with us. In + * this case, stop, dropping the lock. + */ + if (dropped_lock) + goto again; + } + wake_up(&c->free_buffer_wait); + dm_bufio_unlock(c); + + a = xchg(&c->async_write_error, 0); + f = dm_bufio_issue_flush(c); + if (a) + return a; + + return f; +} +EXPORT_SYMBOL_GPL(dm_bufio_write_dirty_buffers); + +/* + * Use dm-io to send and empty barrier flush the device. + */ +int dm_bufio_issue_flush(struct dm_bufio_client *c) +{ + struct dm_io_request io_req = { + .bi_rw = REQ_FLUSH, + .mem.type = DM_IO_KMEM, + .mem.ptr.addr = NULL, + .client = c->dm_io, + }; + struct dm_io_region io_reg = { + .bdev = c->bdev, + .sector = 0, + .count = 0, + }; + + BUG_ON(dm_bufio_in_request()); + + return dm_io(&io_req, 1, &io_reg, NULL); +} +EXPORT_SYMBOL_GPL(dm_bufio_issue_flush); + +/* + * We first delete any other buffer that may be at that new location. + * + * Then, we write the buffer to the original location if it was dirty. + * + * Then, if we are the only one who is holding the buffer, relink the buffer + * in the hash queue for the new location. + * + * If there was someone else holding the buffer, we write it to the new + * location but not relink it, because that other user needs to have the buffer + * at the same place. + */ +void dm_bufio_release_move(struct dm_buffer *b, sector_t new_block) +{ + struct dm_bufio_client *c = b->c; + struct dm_buffer *new; + + BUG_ON(dm_bufio_in_request()); + + dm_bufio_lock(c); + +retry: + new = __find(c, new_block); + if (new) { + if (new->hold_count) { + __wait_for_free_buffer(c); + goto retry; + } + + /* + * FIXME: Is there any point waiting for a write that's going + * to be overwritten in a bit? + */ + __make_buffer_clean(new); + __unlink_buffer(new); + __free_buffer_wake(new); + } + + BUG_ON(!b->hold_count); + BUG_ON(test_bit(B_READING, &b->state)); + + __write_dirty_buffer(b); + if (b->hold_count == 1) { + wait_on_bit(&b->state, B_WRITING, + do_io_schedule, TASK_UNINTERRUPTIBLE); + set_bit(B_DIRTY, &b->state); + __unlink_buffer(b); + __link_buffer(b, new_block, LIST_DIRTY); + } else { + sector_t old_block; + wait_on_bit_lock(&b->state, B_WRITING, + do_io_schedule, TASK_UNINTERRUPTIBLE); + /* + * Relink buffer to "new_block" so that write_callback + * sees "new_block" as a block number. + * After the write, link the buffer back to old_block. + * All this must be done in bufio lock, so that block number + * change isn't visible to other threads. + */ + old_block = b->block; + __unlink_buffer(b); + __link_buffer(b, new_block, b->list_mode); + submit_io(b, WRITE, new_block, write_endio); + wait_on_bit(&b->state, B_WRITING, + do_io_schedule, TASK_UNINTERRUPTIBLE); + __unlink_buffer(b); + __link_buffer(b, old_block, b->list_mode); + } + + dm_bufio_unlock(c); + dm_bufio_release(b); +} +EXPORT_SYMBOL_GPL(dm_bufio_release_move); + +unsigned dm_bufio_get_block_size(struct dm_bufio_client *c) +{ + return c->block_size; +} +EXPORT_SYMBOL_GPL(dm_bufio_get_block_size); + +sector_t dm_bufio_get_device_size(struct dm_bufio_client *c) +{ + return i_size_read(c->bdev->bd_inode) >> + (SECTOR_SHIFT + c->sectors_per_block_bits); +} +EXPORT_SYMBOL_GPL(dm_bufio_get_device_size); + +sector_t dm_bufio_get_block_number(struct dm_buffer *b) +{ + return b->block; +} +EXPORT_SYMBOL_GPL(dm_bufio_get_block_number); + +void *dm_bufio_get_block_data(struct dm_buffer *b) +{ + return b->data; +} +EXPORT_SYMBOL_GPL(dm_bufio_get_block_data); + +void *dm_bufio_get_aux_data(struct dm_buffer *b) +{ + return b + 1; +} +EXPORT_SYMBOL_GPL(dm_bufio_get_aux_data); + +struct dm_bufio_client *dm_bufio_get_client(struct dm_buffer *b) +{ + return b->c; +} +EXPORT_SYMBOL_GPL(dm_bufio_get_client); + +static void drop_buffers(struct dm_bufio_client *c) +{ + struct dm_buffer *b; + int i; + + BUG_ON(dm_bufio_in_request()); + + /* + * An optimization so that the buffers are not written one-by-one. + */ + dm_bufio_write_dirty_buffers_async(c); + + dm_bufio_lock(c); + + while ((b = __get_unclaimed_buffer(c))) + __free_buffer_wake(b); + + for (i = 0; i < LIST_SIZE; i++) + list_for_each_entry(b, &c->lru[i], lru_list) + DMERR("leaked buffer %llx, hold count %u, list %d", + (unsigned long long)b->block, b->hold_count, i); + + for (i = 0; i < LIST_SIZE; i++) + BUG_ON(!list_empty(&c->lru[i])); + + dm_bufio_unlock(c); +} + +/* + * Test if the buffer is unused and too old, and commit it. + * At if noio is set, we must not do any I/O because we hold + * dm_bufio_clients_lock and we would risk deadlock if the I/O gets rerouted to + * different bufio client. + */ +static int __cleanup_old_buffer(struct dm_buffer *b, gfp_t gfp, + unsigned long max_jiffies) +{ + if (jiffies - b->last_accessed < max_jiffies) + return 1; + + if (!(gfp & __GFP_IO)) { + if (test_bit(B_READING, &b->state) || + test_bit(B_WRITING, &b->state) || + test_bit(B_DIRTY, &b->state)) + return 1; + } + + if (b->hold_count) + return 1; + + __make_buffer_clean(b); + __unlink_buffer(b); + __free_buffer_wake(b); + + return 0; +} + +static void __scan(struct dm_bufio_client *c, unsigned long nr_to_scan, + struct shrink_control *sc) +{ + int l; + struct dm_buffer *b, *tmp; + + for (l = 0; l < LIST_SIZE; l++) { + list_for_each_entry_safe_reverse(b, tmp, &c->lru[l], lru_list) + if (!__cleanup_old_buffer(b, sc->gfp_mask, 0) && + !--nr_to_scan) + return; + dm_bufio_cond_resched(); + } +} + +static int shrink(struct shrinker *shrinker, struct shrink_control *sc) +{ + struct dm_bufio_client *c = + container_of(shrinker, struct dm_bufio_client, shrinker); + unsigned long r; + unsigned long nr_to_scan = sc->nr_to_scan; + + if (sc->gfp_mask & __GFP_IO) + dm_bufio_lock(c); + else if (!dm_bufio_trylock(c)) + return !nr_to_scan ? 0 : -1; + + if (nr_to_scan) + __scan(c, nr_to_scan, sc); + + r = c->n_buffers[LIST_CLEAN] + c->n_buffers[LIST_DIRTY]; + if (r > INT_MAX) + r = INT_MAX; + + dm_bufio_unlock(c); + + return r; +} + +/* + * Create the buffering interface + */ +struct dm_bufio_client *dm_bufio_client_create(struct block_device *bdev, unsigned block_size, + unsigned reserved_buffers, unsigned aux_size, + void (*alloc_callback)(struct dm_buffer *), + void (*write_callback)(struct dm_buffer *)) +{ + int r; + struct dm_bufio_client *c; + unsigned i; + + BUG_ON(block_size < 1 << SECTOR_SHIFT || + (block_size & (block_size - 1))); + + c = kmalloc(sizeof(*c), GFP_KERNEL); + if (!c) { + r = -ENOMEM; + goto bad_client; + } + c->cache_hash = vmalloc(sizeof(struct hlist_head) << DM_BUFIO_HASH_BITS); + if (!c->cache_hash) { + r = -ENOMEM; + goto bad_hash; + } + + c->bdev = bdev; + c->block_size = block_size; + c->sectors_per_block_bits = ffs(block_size) - 1 - SECTOR_SHIFT; + c->pages_per_block_bits = (ffs(block_size) - 1 >= PAGE_SHIFT) ? + ffs(block_size) - 1 - PAGE_SHIFT : 0; + c->blocks_per_page_bits = (ffs(block_size) - 1 < PAGE_SHIFT ? + PAGE_SHIFT - (ffs(block_size) - 1) : 0); + + c->aux_size = aux_size; + c->alloc_callback = alloc_callback; + c->write_callback = write_callback; + + for (i = 0; i < LIST_SIZE; i++) { + INIT_LIST_HEAD(&c->lru[i]); + c->n_buffers[i] = 0; + } + + for (i = 0; i < 1 << DM_BUFIO_HASH_BITS; i++) + INIT_HLIST_HEAD(&c->cache_hash[i]); + + mutex_init(&c->lock); + INIT_LIST_HEAD(&c->reserved_buffers); + c->need_reserved_buffers = reserved_buffers; + + init_waitqueue_head(&c->free_buffer_wait); + c->async_write_error = 0; + + c->dm_io = dm_io_client_create(); + if (IS_ERR(c->dm_io)) { + r = PTR_ERR(c->dm_io); + goto bad_dm_io; + } + + mutex_lock(&dm_bufio_clients_lock); + if (c->blocks_per_page_bits) { + if (!DM_BUFIO_CACHE_NAME(c)) { + DM_BUFIO_CACHE_NAME(c) = kasprintf(GFP_KERNEL, "dm_bufio_cache-%u", c->block_size); + if (!DM_BUFIO_CACHE_NAME(c)) { + r = -ENOMEM; + mutex_unlock(&dm_bufio_clients_lock); + goto bad_cache; + } + } + + if (!DM_BUFIO_CACHE(c)) { + DM_BUFIO_CACHE(c) = kmem_cache_create(DM_BUFIO_CACHE_NAME(c), + c->block_size, + c->block_size, 0, NULL); + if (!DM_BUFIO_CACHE(c)) { + r = -ENOMEM; + mutex_unlock(&dm_bufio_clients_lock); + goto bad_cache; + } + } + } + mutex_unlock(&dm_bufio_clients_lock); + + while (c->need_reserved_buffers) { + struct dm_buffer *b = alloc_buffer(c, GFP_KERNEL); + + if (!b) { + r = -ENOMEM; + goto bad_buffer; + } + __free_buffer_wake(b); + } + + mutex_lock(&dm_bufio_clients_lock); + dm_bufio_client_count++; + list_add(&c->client_list, &dm_bufio_all_clients); + __cache_size_refresh(); + mutex_unlock(&dm_bufio_clients_lock); + + c->shrinker.shrink = shrink; + c->shrinker.seeks = 1; + c->shrinker.batch = 0; + register_shrinker(&c->shrinker); + + return c; + +bad_buffer: +bad_cache: + while (!list_empty(&c->reserved_buffers)) { + struct dm_buffer *b = list_entry(c->reserved_buffers.next, + struct dm_buffer, lru_list); + list_del(&b->lru_list); + free_buffer(b); + } + dm_io_client_destroy(c->dm_io); +bad_dm_io: + vfree(c->cache_hash); +bad_hash: + kfree(c); +bad_client: + return ERR_PTR(r); +} +EXPORT_SYMBOL_GPL(dm_bufio_client_create); + +/* + * Free the buffering interface. + * It is required that there are no references on any buffers. + */ +void dm_bufio_client_destroy(struct dm_bufio_client *c) +{ + unsigned i; + + drop_buffers(c); + + unregister_shrinker(&c->shrinker); + + mutex_lock(&dm_bufio_clients_lock); + + list_del(&c->client_list); + dm_bufio_client_count--; + __cache_size_refresh(); + + mutex_unlock(&dm_bufio_clients_lock); + + for (i = 0; i < 1 << DM_BUFIO_HASH_BITS; i++) + BUG_ON(!hlist_empty(&c->cache_hash[i])); + + BUG_ON(c->need_reserved_buffers); + + while (!list_empty(&c->reserved_buffers)) { + struct dm_buffer *b = list_entry(c->reserved_buffers.next, + struct dm_buffer, lru_list); + list_del(&b->lru_list); + free_buffer(b); + } + + for (i = 0; i < LIST_SIZE; i++) + if (c->n_buffers[i]) + DMERR("leaked buffer count %d: %ld", i, c->n_buffers[i]); + + for (i = 0; i < LIST_SIZE; i++) + BUG_ON(c->n_buffers[i]); + + dm_io_client_destroy(c->dm_io); + vfree(c->cache_hash); + kfree(c); +} +EXPORT_SYMBOL_GPL(dm_bufio_client_destroy); + +static void cleanup_old_buffers(void) +{ + unsigned long max_age = dm_bufio_max_age; + struct dm_bufio_client *c; + + barrier(); + + if (max_age > ULONG_MAX / HZ) + max_age = ULONG_MAX / HZ; + + mutex_lock(&dm_bufio_clients_lock); + list_for_each_entry(c, &dm_bufio_all_clients, client_list) { + if (!dm_bufio_trylock(c)) + continue; + + while (!list_empty(&c->lru[LIST_CLEAN])) { + struct dm_buffer *b; + b = list_entry(c->lru[LIST_CLEAN].prev, + struct dm_buffer, lru_list); + if (__cleanup_old_buffer(b, 0, max_age * HZ)) + break; + dm_bufio_cond_resched(); + } + + dm_bufio_unlock(c); + dm_bufio_cond_resched(); + } + mutex_unlock(&dm_bufio_clients_lock); +} + +static struct workqueue_struct *dm_bufio_wq; +static struct delayed_work dm_bufio_work; + +static void work_fn(struct work_struct *w) +{ + cleanup_old_buffers(); + + queue_delayed_work(dm_bufio_wq, &dm_bufio_work, + DM_BUFIO_WORK_TIMER_SECS * HZ); +} + +/*---------------------------------------------------------------- + * Module setup + *--------------------------------------------------------------*/ + +/* + * This is called only once for the whole dm_bufio module. + * It initializes memory limit. + */ +static int __init dm_bufio_init(void) +{ + __u64 mem; + + memset(&dm_bufio_caches, 0, sizeof dm_bufio_caches); + memset(&dm_bufio_cache_names, 0, sizeof dm_bufio_cache_names); + + mem = (__u64)((totalram_pages - totalhigh_pages) * + DM_BUFIO_MEMORY_PERCENT / 100) << PAGE_SHIFT; + + if (mem > ULONG_MAX) + mem = ULONG_MAX; + +#ifdef CONFIG_MMU + /* + * Get the size of vmalloc space the same way as VMALLOC_TOTAL + * in fs/proc/internal.h + */ + if (mem > (VMALLOC_END - VMALLOC_START) * DM_BUFIO_VMALLOC_PERCENT / 100) + mem = (VMALLOC_END - VMALLOC_START) * DM_BUFIO_VMALLOC_PERCENT / 100; +#endif + + dm_bufio_default_cache_size = mem; + + mutex_lock(&dm_bufio_clients_lock); + __cache_size_refresh(); + mutex_unlock(&dm_bufio_clients_lock); + + dm_bufio_wq = create_singlethread_workqueue("dm_bufio_cache"); + if (!dm_bufio_wq) + return -ENOMEM; + + INIT_DELAYED_WORK(&dm_bufio_work, work_fn); + queue_delayed_work(dm_bufio_wq, &dm_bufio_work, + DM_BUFIO_WORK_TIMER_SECS * HZ); + + return 0; +} + +/* + * This is called once when unloading the dm_bufio module. + */ +static void __exit dm_bufio_exit(void) +{ + int bug = 0; + int i; + + cancel_delayed_work_sync(&dm_bufio_work); + destroy_workqueue(dm_bufio_wq); + + for (i = 0; i < ARRAY_SIZE(dm_bufio_caches); i++) { + struct kmem_cache *kc = dm_bufio_caches[i]; + + if (kc) + kmem_cache_destroy(kc); + } + + for (i = 0; i < ARRAY_SIZE(dm_bufio_cache_names); i++) + kfree(dm_bufio_cache_names[i]); + + if (dm_bufio_client_count) { + DMCRIT("%s: dm_bufio_client_count leaked: %d", + __func__, dm_bufio_client_count); + bug = 1; + } + + if (dm_bufio_current_allocated) { + DMCRIT("%s: dm_bufio_current_allocated leaked: %lu", + __func__, dm_bufio_current_allocated); + bug = 1; + } + + if (dm_bufio_allocated_get_free_pages) { + DMCRIT("%s: dm_bufio_allocated_get_free_pages leaked: %lu", + __func__, dm_bufio_allocated_get_free_pages); + bug = 1; + } + + if (dm_bufio_allocated_vmalloc) { + DMCRIT("%s: dm_bufio_vmalloc leaked: %lu", + __func__, dm_bufio_allocated_vmalloc); + bug = 1; + } + + if (bug) + BUG(); +} + +module_init(dm_bufio_init) +module_exit(dm_bufio_exit) + +module_param_named(max_cache_size_bytes, dm_bufio_cache_size, ulong, S_IRUGO | S_IWUSR); +MODULE_PARM_DESC(max_cache_size_bytes, "Size of metadata cache"); + +module_param_named(max_age_seconds, dm_bufio_max_age, uint, S_IRUGO | S_IWUSR); +MODULE_PARM_DESC(max_age_seconds, "Max age of a buffer in seconds"); + +module_param_named(peak_allocated_bytes, dm_bufio_peak_allocated, ulong, S_IRUGO | S_IWUSR); +MODULE_PARM_DESC(peak_allocated_bytes, "Tracks the maximum allocated memory"); + +module_param_named(allocated_kmem_cache_bytes, dm_bufio_allocated_kmem_cache, ulong, S_IRUGO); +MODULE_PARM_DESC(allocated_kmem_cache_bytes, "Memory allocated with kmem_cache_alloc"); + +module_param_named(allocated_get_free_pages_bytes, dm_bufio_allocated_get_free_pages, ulong, S_IRUGO); +MODULE_PARM_DESC(allocated_get_free_pages_bytes, "Memory allocated with get_free_pages"); + +module_param_named(allocated_vmalloc_bytes, dm_bufio_allocated_vmalloc, ulong, S_IRUGO); +MODULE_PARM_DESC(allocated_vmalloc_bytes, "Memory allocated with vmalloc"); + +module_param_named(current_allocated_bytes, dm_bufio_current_allocated, ulong, S_IRUGO); +MODULE_PARM_DESC(current_allocated_bytes, "Memory currently used by the cache"); + +MODULE_AUTHOR("Mikulas Patocka <dm-devel@redhat.com>"); +MODULE_DESCRIPTION(DM_NAME " buffered I/O library"); +MODULE_LICENSE("GPL"); diff --git a/drivers/md/dm-bufio.h b/drivers/md/dm-bufio.h new file mode 100644 index 00000000000..5c4c3a04e38 --- /dev/null +++ b/drivers/md/dm-bufio.h @@ -0,0 +1,112 @@ +/* + * Copyright (C) 2009-2011 Red Hat, Inc. + * + * Author: Mikulas Patocka <mpatocka@redhat.com> + * + * This file is released under the GPL. + */ + +#ifndef DM_BUFIO_H +#define DM_BUFIO_H + +#include <linux/blkdev.h> +#include <linux/types.h> + +/*----------------------------------------------------------------*/ + +struct dm_bufio_client; +struct dm_buffer; + +/* + * Create a buffered IO cache on a given device + */ +struct dm_bufio_client * +dm_bufio_client_create(struct block_device *bdev, unsigned block_size, + unsigned reserved_buffers, unsigned aux_size, + void (*alloc_callback)(struct dm_buffer *), + void (*write_callback)(struct dm_buffer *)); + +/* + * Release a buffered IO cache. + */ +void dm_bufio_client_destroy(struct dm_bufio_client *c); + +/* + * WARNING: to avoid deadlocks, these conditions are observed: + * + * - At most one thread can hold at most "reserved_buffers" simultaneously. + * - Each other threads can hold at most one buffer. + * - Threads which call only dm_bufio_get can hold unlimited number of + * buffers. + */ + +/* + * Read a given block from disk. Returns pointer to data. Returns a + * pointer to dm_buffer that can be used to release the buffer or to make + * it dirty. + */ +void *dm_bufio_read(struct dm_bufio_client *c, sector_t block, + struct dm_buffer **bp); + +/* + * Like dm_bufio_read, but return buffer from cache, don't read + * it. If the buffer is not in the cache, return NULL. + */ +void *dm_bufio_get(struct dm_bufio_client *c, sector_t block, + struct dm_buffer **bp); + +/* + * Like dm_bufio_read, but don't read anything from the disk. It is + * expected that the caller initializes the buffer and marks it dirty. + */ +void *dm_bufio_new(struct dm_bufio_client *c, sector_t block, + struct dm_buffer **bp); + +/* + * Release a reference obtained with dm_bufio_{read,get,new}. The data + * pointer and dm_buffer pointer is no longer valid after this call. + */ +void dm_bufio_release(struct dm_buffer *b); + +/* + * Mark a buffer dirty. It should be called after the buffer is modified. + * + * In case of memory pressure, the buffer may be written after + * dm_bufio_mark_buffer_dirty, but before dm_bufio_write_dirty_buffers. So + * dm_bufio_write_dirty_buffers guarantees that the buffer is on-disk but + * the actual writing may occur earlier. + */ +void dm_bufio_mark_buffer_dirty(struct dm_buffer *b); + +/* + * Initiate writing of dirty buffers, without waiting for completion. + */ +void dm_bufio_write_dirty_buffers_async(struct dm_bufio_client *c); + +/* + * Write all dirty buffers. Guarantees that all dirty buffers created prior + * to this call are on disk when this call exits. + */ +int dm_bufio_write_dirty_buffers(struct dm_bufio_client *c); + +/* + * Send an empty write barrier to the device to flush hardware disk cache. + */ +int dm_bufio_issue_flush(struct dm_bufio_client *c); + +/* + * Like dm_bufio_release but also move the buffer to the new + * block. dm_bufio_write_dirty_buffers is needed to commit the new block. + */ +void dm_bufio_release_move(struct dm_buffer *b, sector_t new_block); + +unsigned dm_bufio_get_block_size(struct dm_bufio_client *c); +sector_t dm_bufio_get_device_size(struct dm_bufio_client *c); +sector_t dm_bufio_get_block_number(struct dm_buffer *b); +void *dm_bufio_get_block_data(struct dm_buffer *b); +void *dm_bufio_get_aux_data(struct dm_buffer *b); +struct dm_bufio_client *dm_bufio_get_client(struct dm_buffer *b); + +/*----------------------------------------------------------------*/ + +#endif diff --git a/drivers/md/dm-exception-store.c b/drivers/md/dm-exception-store.c index 0bdb201c2c2..042e7199656 100644 --- a/drivers/md/dm-exception-store.c +++ b/drivers/md/dm-exception-store.c @@ -11,6 +11,7 @@ #include <linux/mm.h> #include <linux/pagemap.h> #include <linux/vmalloc.h> +#include <linux/module.h> #include <linux/slab.h> #define DM_MSG_PREFIX "snapshot exception stores" diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c index 2e9a3ca37bd..31c2dc25886 100644 --- a/drivers/md/dm-ioctl.c +++ b/drivers/md/dm-ioctl.c @@ -1215,6 +1215,7 @@ static int table_load(struct dm_ioctl *param, size_t param_size) struct hash_cell *hc; struct dm_table *t; struct mapped_device *md; + struct target_type *immutable_target_type; md = find_device(param); if (!md) @@ -1230,6 +1231,16 @@ static int table_load(struct dm_ioctl *param, size_t param_size) goto out; } + immutable_target_type = dm_get_immutable_target_type(md); + if (immutable_target_type && + (immutable_target_type != dm_table_get_immutable_target_type(t))) { + DMWARN("can't replace immutable target type %s", + immutable_target_type->name); + dm_table_destroy(t); + r = -EINVAL; + goto out; + } + /* Protect md->type and md->queue against concurrent table loads. */ dm_lock_md_type(md); if (dm_get_md_type(md) == DM_TYPE_NONE) diff --git a/drivers/md/dm-kcopyd.c b/drivers/md/dm-kcopyd.c index 32ac70861d6..bed444c93d8 100644 --- a/drivers/md/dm-kcopyd.c +++ b/drivers/md/dm-kcopyd.c @@ -66,6 +66,8 @@ struct dm_kcopyd_client { struct list_head pages_jobs; }; +static struct page_list zero_page_list; + static void wake(struct dm_kcopyd_client *kc) { queue_work(kc->kcopyd_wq, &kc->kcopyd_work); @@ -254,6 +256,9 @@ int __init dm_kcopyd_init(void) if (!_job_cache) return -ENOMEM; + zero_page_list.next = &zero_page_list; + zero_page_list.page = ZERO_PAGE(0); + return 0; } @@ -322,7 +327,7 @@ static int run_complete_job(struct kcopyd_job *job) dm_kcopyd_notify_fn fn = job->fn; struct dm_kcopyd_client *kc = job->kc; - if (job->pages) + if (job->pages && job->pages != &zero_page_list) kcopyd_put_pages(kc, job->pages); /* * If this is the master job, the sub jobs have already @@ -484,6 +489,8 @@ static void dispatch_job(struct kcopyd_job *job) atomic_inc(&kc->nr_jobs); if (unlikely(!job->source.count)) push(&kc->complete_jobs, job); + else if (job->pages == &zero_page_list) + push(&kc->io_jobs, job); else push(&kc->pages_jobs, job); wake(kc); @@ -592,14 +599,20 @@ int dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from, job->flags = flags; job->read_err = 0; job->write_err = 0; - job->rw = READ; - - job->source = *from; job->num_dests = num_dests; memcpy(&job->dests, dests, sizeof(*dests) * num_dests); - job->pages = NULL; + if (from) { + job->source = *from; + job->pages = NULL; + job->rw = READ; + } else { + memset(&job->source, 0, sizeof job->source); + job->source.count = job->dests[0].count; + job->pages = &zero_page_list; + job->rw = WRITE; + } job->fn = fn; job->context = context; @@ -617,6 +630,14 @@ int dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from, } EXPORT_SYMBOL(dm_kcopyd_copy); +int dm_kcopyd_zero(struct dm_kcopyd_client *kc, + unsigned num_dests, struct dm_io_region *dests, + unsigned flags, dm_kcopyd_notify_fn fn, void *context) +{ + return dm_kcopyd_copy(kc, NULL, num_dests, dests, flags, fn, context); +} +EXPORT_SYMBOL(dm_kcopyd_zero); + void *dm_kcopyd_prepare_callback(struct dm_kcopyd_client *kc, dm_kcopyd_notify_fn fn, void *context) { diff --git a/drivers/md/dm-log-userspace-base.c b/drivers/md/dm-log-userspace-base.c index 1021c898601..9429159d9ee 100644 --- a/drivers/md/dm-log-userspace-base.c +++ b/drivers/md/dm-log-userspace-base.c @@ -9,6 +9,7 @@ #include <linux/dm-dirty-log.h> #include <linux/device-mapper.h> #include <linux/dm-log-userspace.h> +#include <linux/module.h> #include "dm-log-userspace-transfer.h" @@ -30,6 +31,7 @@ struct flush_entry { struct log_c { struct dm_target *ti; + struct dm_dev *log_dev; uint32_t region_size; region_t region_count; uint64_t luid; @@ -146,7 +148,7 @@ static int build_constructor_string(struct dm_target *ti, * <UUID> <other args> * Where 'other args' is the userspace implementation specific log * arguments. An example might be: - * <UUID> clustered_disk <arg count> <log dev> <region_size> [[no]sync] + * <UUID> clustered-disk <arg count> <log dev> <region_size> [[no]sync] * * So, this module will strip off the <UUID> for identification purposes * when communicating with userspace about a log; but will pass on everything @@ -161,13 +163,15 @@ static int userspace_ctr(struct dm_dirty_log *log, struct dm_target *ti, struct log_c *lc = NULL; uint64_t rdata; size_t rdata_size = sizeof(rdata); + char *devices_rdata = NULL; + size_t devices_rdata_size = DM_NAME_LEN; if (argc < 3) { DMWARN("Too few arguments to userspace dirty log"); return -EINVAL; } - lc = kmalloc(sizeof(*lc), GFP_KERNEL); + lc = kzalloc(sizeof(*lc), GFP_KERNEL); if (!lc) { DMWARN("Unable to allocate userspace log context."); return -ENOMEM; @@ -195,9 +199,19 @@ static int userspace_ctr(struct dm_dirty_log *log, struct dm_target *ti, return str_size; } - /* Send table string */ + devices_rdata = kzalloc(devices_rdata_size, GFP_KERNEL); + if (!devices_rdata) { + DMERR("Failed to allocate memory for device information"); + r = -ENOMEM; + goto out; + } + + /* + * Send table string and get back any opened device. + */ r = dm_consult_userspace(lc->uuid, lc->luid, DM_ULOG_CTR, - ctr_str, str_size, NULL, NULL); + ctr_str, str_size, + devices_rdata, &devices_rdata_size); if (r < 0) { if (r == -ESRCH) @@ -220,7 +234,20 @@ static int userspace_ctr(struct dm_dirty_log *log, struct dm_target *ti, lc->region_size = (uint32_t)rdata; lc->region_count = dm_sector_div_up(ti->len, lc->region_size); + if (devices_rdata_size) { + if (devices_rdata[devices_rdata_size - 1] != '\0') { + DMERR("DM_ULOG_CTR device return string not properly terminated"); + r = -EINVAL; + goto out; + } + r = dm_get_device(ti, devices_rdata, + dm_table_get_mode(ti->table), &lc->log_dev); + if (r) + DMERR("Failed to register %s with device-mapper", + devices_rdata); + } out: + kfree(devices_rdata); if (r) { kfree(lc); kfree(ctr_str); @@ -241,6 +268,9 @@ static void userspace_dtr(struct dm_dirty_log *log) NULL, 0, NULL, NULL); + if (lc->log_dev) + dm_put_device(lc->ti, lc->log_dev); + kfree(lc->usr_argv_str); kfree(lc); diff --git a/drivers/md/dm-path-selector.c b/drivers/md/dm-path-selector.c index 42c04f04a0c..fa0ccc585cb 100644 --- a/drivers/md/dm-path-selector.c +++ b/drivers/md/dm-path-selector.c @@ -10,6 +10,7 @@ */ #include <linux/device-mapper.h> +#include <linux/module.h> #include "dm-path-selector.h" diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c index 37a37266a1e..c2907d836e4 100644 --- a/drivers/md/dm-raid.c +++ b/drivers/md/dm-raid.c @@ -6,6 +6,7 @@ */ #include <linux/slab.h> +#include <linux/module.h> #include "md.h" #include "raid1.h" @@ -1017,30 +1018,56 @@ static int raid_status(struct dm_target *ti, status_type_t type, struct raid_set *rs = ti->private; unsigned raid_param_cnt = 1; /* at least 1 for chunksize */ unsigned sz = 0; - int i; + int i, array_in_sync = 0; sector_t sync; switch (type) { case STATUSTYPE_INFO: DMEMIT("%s %d ", rs->raid_type->name, rs->md.raid_disks); - for (i = 0; i < rs->md.raid_disks; i++) { - if (test_bit(Faulty, &rs->dev[i].rdev.flags)) - DMEMIT("D"); - else if (test_bit(In_sync, &rs->dev[i].rdev.flags)) - DMEMIT("A"); - else - DMEMIT("a"); - } - if (test_bit(MD_RECOVERY_RUNNING, &rs->md.recovery)) sync = rs->md.curr_resync_completed; else sync = rs->md.recovery_cp; - if (sync > rs->md.resync_max_sectors) + if (sync >= rs->md.resync_max_sectors) { + array_in_sync = 1; sync = rs->md.resync_max_sectors; + } else { + /* + * The array may be doing an initial sync, or it may + * be rebuilding individual components. If all the + * devices are In_sync, then it is the array that is + * being initialized. + */ + for (i = 0; i < rs->md.raid_disks; i++) + if (!test_bit(In_sync, &rs->dev[i].rdev.flags)) + array_in_sync = 1; + } + /* + * Status characters: + * 'D' = Dead/Failed device + * 'a' = Alive but not in-sync + * 'A' = Alive and in-sync + */ + for (i = 0; i < rs->md.raid_disks; i++) { + if (test_bit(Faulty, &rs->dev[i].rdev.flags)) + DMEMIT("D"); + else if (!array_in_sync || + !test_bit(In_sync, &rs->dev[i].rdev.flags)) + DMEMIT("a"); + else + DMEMIT("A"); + } + /* + * In-sync ratio: + * The in-sync ratio shows the progress of: + * - Initializing the array + * - Rebuilding a subset of devices of the array + * The user can distinguish between the two by referring + * to the status characters. + */ DMEMIT(" %llu/%llu", (unsigned long long) sync, (unsigned long long) rs->md.resync_max_sectors); diff --git a/drivers/md/dm-round-robin.c b/drivers/md/dm-round-robin.c index 24752f449be..27f1d423b76 100644 --- a/drivers/md/dm-round-robin.c +++ b/drivers/md/dm-round-robin.c @@ -14,6 +14,7 @@ #include "dm-path-selector.h" #include <linux/slab.h> +#include <linux/module.h> #define DM_MSG_PREFIX "multipath round-robin" diff --git a/drivers/md/dm-service-time.c b/drivers/md/dm-service-time.c index 9c6c2e47ad6..59883bd7821 100644 --- a/drivers/md/dm-service-time.c +++ b/drivers/md/dm-service-time.c @@ -12,6 +12,7 @@ #include "dm-path-selector.h" #include <linux/slab.h> +#include <linux/module.h> #define DM_MSG_PREFIX "multipath service-time" #define ST_MIN_IO 1 diff --git a/drivers/md/dm-snap-persistent.c b/drivers/md/dm-snap-persistent.c index d1f1d701710..3ac415675b6 100644 --- a/drivers/md/dm-snap-persistent.c +++ b/drivers/md/dm-snap-persistent.c @@ -10,6 +10,7 @@ #include <linux/mm.h> #include <linux/pagemap.h> #include <linux/vmalloc.h> +#include <linux/export.h> #include <linux/slab.h> #include <linux/dm-io.h> diff --git a/drivers/md/dm-snap-transient.c b/drivers/md/dm-snap-transient.c index a0898a66a2f..1ce9a2586e4 100644 --- a/drivers/md/dm-snap-transient.c +++ b/drivers/md/dm-snap-transient.c @@ -10,6 +10,7 @@ #include <linux/mm.h> #include <linux/pagemap.h> #include <linux/vmalloc.h> +#include <linux/export.h> #include <linux/slab.h> #include <linux/dm-io.h> diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index bc04518e9d8..8e913213014 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -54,7 +54,9 @@ struct dm_table { sector_t *highs; struct dm_target *targets; + struct target_type *immutable_target_type; unsigned integrity_supported:1; + unsigned singleton:1; /* * Indicates the rw permissions for the new logical @@ -740,6 +742,12 @@ int dm_table_add_target(struct dm_table *t, const char *type, char **argv; struct dm_target *tgt; + if (t->singleton) { + DMERR("%s: target type %s must appear alone in table", + dm_device_name(t->md), t->targets->type->name); + return -EINVAL; + } + if ((r = check_space(t))) return r; @@ -758,6 +766,36 @@ int dm_table_add_target(struct dm_table *t, const char *type, return -EINVAL; } + if (dm_target_needs_singleton(tgt->type)) { + if (t->num_targets) { + DMERR("%s: target type %s must appear alone in table", + dm_device_name(t->md), type); + return -EINVAL; + } + t->singleton = 1; + } + + if (dm_target_always_writeable(tgt->type) && !(t->mode & FMODE_WRITE)) { + DMERR("%s: target type %s may not be included in read-only tables", + dm_device_name(t->md), type); + return -EINVAL; + } + + if (t->immutable_target_type) { + if (t->immutable_target_type != tgt->type) { + DMERR("%s: immutable target type %s cannot be mixed with other target types", + dm_device_name(t->md), t->immutable_target_type->name); + return -EINVAL; + } + } else if (dm_target_is_immutable(tgt->type)) { + if (t->num_targets) { + DMERR("%s: immutable target type %s cannot be mixed with other target types", + dm_device_name(t->md), tgt->type->name); + return -EINVAL; + } + t->immutable_target_type = tgt->type; + } + tgt->table = t; tgt->begin = start; tgt->len = len; @@ -915,6 +953,11 @@ unsigned dm_table_get_type(struct dm_table *t) return t->type; } +struct target_type *dm_table_get_immutable_target_type(struct dm_table *t) +{ + return t->immutable_target_type; +} + bool dm_table_request_based(struct dm_table *t) { return dm_table_get_type(t) == DM_TYPE_REQUEST_BASED; @@ -1299,6 +1342,31 @@ static bool dm_table_discard_zeroes_data(struct dm_table *t) return 1; } +static int device_is_nonrot(struct dm_target *ti, struct dm_dev *dev, + sector_t start, sector_t len, void *data) +{ + struct request_queue *q = bdev_get_queue(dev->bdev); + + return q && blk_queue_nonrot(q); +} + +static bool dm_table_is_nonrot(struct dm_table *t) +{ + struct dm_target *ti; + unsigned i = 0; + + /* Ensure that all underlying device are non-rotational. */ + while (i < dm_table_get_num_targets(t)) { + ti = dm_table_get_target(t, i++); + + if (!ti->type->iterate_devices || + !ti->type->iterate_devices(ti, device_is_nonrot, NULL)) + return 0; + } + + return 1; +} + void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q, struct queue_limits *limits) { @@ -1324,6 +1392,11 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q, if (!dm_table_discard_zeroes_data(t)) q->limits.discard_zeroes_data = 0; + if (dm_table_is_nonrot(t)) + queue_flag_set_unlocked(QUEUE_FLAG_NONROT, q); + else + queue_flag_clear_unlocked(QUEUE_FLAG_NONROT, q); + dm_table_set_integrity(t); /* diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c new file mode 100644 index 00000000000..59c4f0446ff --- /dev/null +++ b/drivers/md/dm-thin-metadata.c @@ -0,0 +1,1391 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#include "dm-thin-metadata.h" +#include "persistent-data/dm-btree.h" +#include "persistent-data/dm-space-map.h" +#include "persistent-data/dm-space-map-disk.h" +#include "persistent-data/dm-transaction-manager.h" + +#include <linux/list.h> +#include <linux/device-mapper.h> +#include <linux/workqueue.h> + +/*-------------------------------------------------------------------------- + * As far as the metadata goes, there is: + * + * - A superblock in block zero, taking up fewer than 512 bytes for + * atomic writes. + * + * - A space map managing the metadata blocks. + * + * - A space map managing the data blocks. + * + * - A btree mapping our internal thin dev ids onto struct disk_device_details. + * + * - A hierarchical btree, with 2 levels which effectively maps (thin + * dev id, virtual block) -> block_time. Block time is a 64-bit + * field holding the time in the low 24 bits, and block in the top 48 + * bits. + * + * BTrees consist solely of btree_nodes, that fill a block. Some are + * internal nodes, as such their values are a __le64 pointing to other + * nodes. Leaf nodes can store data of any reasonable size (ie. much + * smaller than the block size). The nodes consist of the header, + * followed by an array of keys, followed by an array of values. We have + * to binary search on the keys so they're all held together to help the + * cpu cache. + * + * Space maps have 2 btrees: + * + * - One maps a uint64_t onto a struct index_entry. Which points to a + * bitmap block, and has some details about how many free entries there + * are etc. + * + * - The bitmap blocks have a header (for the checksum). Then the rest + * of the block is pairs of bits. With the meaning being: + * + * 0 - ref count is 0 + * 1 - ref count is 1 + * 2 - ref count is 2 + * 3 - ref count is higher than 2 + * + * - If the count is higher than 2 then the ref count is entered in a + * second btree that directly maps the block_address to a uint32_t ref + * count. + * + * The space map metadata variant doesn't have a bitmaps btree. Instead + * it has one single blocks worth of index_entries. This avoids + * recursive issues with the bitmap btree needing to allocate space in + * order to insert. With a small data block size such as 64k the + * metadata support data devices that are hundreds of terrabytes. + * + * The space maps allocate space linearly from front to back. Space that + * is freed in a transaction is never recycled within that transaction. + * To try and avoid fragmenting _free_ space the allocator always goes + * back and fills in gaps. + * + * All metadata io is in THIN_METADATA_BLOCK_SIZE sized/aligned chunks + * from the block manager. + *--------------------------------------------------------------------------*/ + +#define DM_MSG_PREFIX "thin metadata" + +#define THIN_SUPERBLOCK_MAGIC 27022010 +#define THIN_SUPERBLOCK_LOCATION 0 +#define THIN_VERSION 1 +#define THIN_METADATA_CACHE_SIZE 64 +#define SECTOR_TO_BLOCK_SHIFT 3 + +/* This should be plenty */ +#define SPACE_MAP_ROOT_SIZE 128 + +/* + * Little endian on-disk superblock and device details. + */ +struct thin_disk_superblock { + __le32 csum; /* Checksum of superblock except for this field. */ + __le32 flags; + __le64 blocknr; /* This block number, dm_block_t. */ + + __u8 uuid[16]; + __le64 magic; + __le32 version; + __le32 time; + + __le64 trans_id; + + /* + * Root held by userspace transactions. + */ + __le64 held_root; + + __u8 data_space_map_root[SPACE_MAP_ROOT_SIZE]; + __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE]; + + /* + * 2-level btree mapping (dev_id, (dev block, time)) -> data block + */ + __le64 data_mapping_root; + + /* + * Device detail root mapping dev_id -> device_details + */ + __le64 device_details_root; + + __le32 data_block_size; /* In 512-byte sectors. */ + + __le32 metadata_block_size; /* In 512-byte sectors. */ + __le64 metadata_nr_blocks; + + __le32 compat_flags; + __le32 compat_ro_flags; + __le32 incompat_flags; +} __packed; + +struct disk_device_details { + __le64 mapped_blocks; + __le64 transaction_id; /* When created. */ + __le32 creation_time; + __le32 snapshotted_time; +} __packed; + +struct dm_pool_metadata { + struct hlist_node hash; + + struct block_device *bdev; + struct dm_block_manager *bm; + struct dm_space_map *metadata_sm; + struct dm_space_map *data_sm; + struct dm_transaction_manager *tm; + struct dm_transaction_manager *nb_tm; + + /* + * Two-level btree. + * First level holds thin_dev_t. + * Second level holds mappings. + */ + struct dm_btree_info info; + + /* + * Non-blocking version of the above. + */ + struct dm_btree_info nb_info; + + /* + * Just the top level for deleting whole devices. + */ + struct dm_btree_info tl_info; + + /* + * Just the bottom level for creating new devices. + */ + struct dm_btree_info bl_info; + + /* + * Describes the device details btree. + */ + struct dm_btree_info details_info; + + struct rw_semaphore root_lock; + uint32_t time; + int need_commit; + dm_block_t root; + dm_block_t details_root; + struct list_head thin_devices; + uint64_t trans_id; + unsigned long flags; + sector_t data_block_size; +}; + +struct dm_thin_device { + struct list_head list; + struct dm_pool_metadata *pmd; + dm_thin_id id; + + int open_count; + int changed; + uint64_t mapped_blocks; + uint64_t transaction_id; + uint32_t creation_time; + uint32_t snapshotted_time; +}; + +/*---------------------------------------------------------------- + * superblock validator + *--------------------------------------------------------------*/ + +#define SUPERBLOCK_CSUM_XOR 160774 + +static void sb_prepare_for_write(struct dm_block_validator *v, + struct dm_block *b, + size_t block_size) +{ + struct thin_disk_superblock *disk_super = dm_block_data(b); + + disk_super->blocknr = cpu_to_le64(dm_block_location(b)); + disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags, + block_size - sizeof(__le32), + SUPERBLOCK_CSUM_XOR)); +} + +static int sb_check(struct dm_block_validator *v, + struct dm_block *b, + size_t block_size) +{ + struct thin_disk_superblock *disk_super = dm_block_data(b); + __le32 csum_le; + + if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) { + DMERR("sb_check failed: blocknr %llu: " + "wanted %llu", le64_to_cpu(disk_super->blocknr), + (unsigned long long)dm_block_location(b)); + return -ENOTBLK; + } + + if (le64_to_cpu(disk_super->magic) != THIN_SUPERBLOCK_MAGIC) { + DMERR("sb_check failed: magic %llu: " + "wanted %llu", le64_to_cpu(disk_super->magic), + (unsigned long long)THIN_SUPERBLOCK_MAGIC); + return -EILSEQ; + } + + csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags, + block_size - sizeof(__le32), + SUPERBLOCK_CSUM_XOR)); + if (csum_le != disk_super->csum) { + DMERR("sb_check failed: csum %u: wanted %u", + le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum)); + return -EILSEQ; + } + + return 0; +} + +static struct dm_block_validator sb_validator = { + .name = "superblock", + .prepare_for_write = sb_prepare_for_write, + .check = sb_check +}; + +/*---------------------------------------------------------------- + * Methods for the btree value types + *--------------------------------------------------------------*/ + +static uint64_t pack_block_time(dm_block_t b, uint32_t t) +{ + return (b << 24) | t; +} + +static void unpack_block_time(uint64_t v, dm_block_t *b, uint32_t *t) +{ + *b = v >> 24; + *t = v & ((1 << 24) - 1); +} + +static void data_block_inc(void *context, void *value_le) +{ + struct dm_space_map *sm = context; + __le64 v_le; + uint64_t b; + uint32_t t; + + memcpy(&v_le, value_le, sizeof(v_le)); + unpack_block_time(le64_to_cpu(v_le), &b, &t); + dm_sm_inc_block(sm, b); +} + +static void data_block_dec(void *context, void *value_le) +{ + struct dm_space_map *sm = context; + __le64 v_le; + uint64_t b; + uint32_t t; + + memcpy(&v_le, value_le, sizeof(v_le)); + unpack_block_time(le64_to_cpu(v_le), &b, &t); + dm_sm_dec_block(sm, b); +} + +static int data_block_equal(void *context, void *value1_le, void *value2_le) +{ + __le64 v1_le, v2_le; + uint64_t b1, b2; + uint32_t t; + + memcpy(&v1_le, value1_le, sizeof(v1_le)); + memcpy(&v2_le, value2_le, sizeof(v2_le)); + unpack_block_time(le64_to_cpu(v1_le), &b1, &t); + unpack_block_time(le64_to_cpu(v2_le), &b2, &t); + + return b1 == b2; +} + +static void subtree_inc(void *context, void *value) +{ + struct dm_btree_info *info = context; + __le64 root_le; + uint64_t root; + + memcpy(&root_le, value, sizeof(root_le)); + root = le64_to_cpu(root_le); + dm_tm_inc(info->tm, root); +} + +static void subtree_dec(void *context, void *value) +{ + struct dm_btree_info *info = context; + __le64 root_le; + uint64_t root; + + memcpy(&root_le, value, sizeof(root_le)); + root = le64_to_cpu(root_le); + if (dm_btree_del(info, root)) + DMERR("btree delete failed\n"); +} + +static int subtree_equal(void *context, void *value1_le, void *value2_le) +{ + __le64 v1_le, v2_le; + memcpy(&v1_le, value1_le, sizeof(v1_le)); + memcpy(&v2_le, value2_le, sizeof(v2_le)); + + return v1_le == v2_le; +} + +/*----------------------------------------------------------------*/ + +static int superblock_all_zeroes(struct dm_block_manager *bm, int *result) +{ + int r; + unsigned i; + struct dm_block *b; + __le64 *data_le, zero = cpu_to_le64(0); + unsigned block_size = dm_bm_block_size(bm) / sizeof(__le64); + + /* + * We can't use a validator here - it may be all zeroes. + */ + r = dm_bm_read_lock(bm, THIN_SUPERBLOCK_LOCATION, NULL, &b); + if (r) + return r; + + data_le = dm_block_data(b); + *result = 1; + for (i = 0; i < block_size; i++) { + if (data_le[i] != zero) { + *result = 0; + break; + } + } + + return dm_bm_unlock(b); +} + +static int init_pmd(struct dm_pool_metadata *pmd, + struct dm_block_manager *bm, + dm_block_t nr_blocks, int create) +{ + int r; + struct dm_space_map *sm, *data_sm; + struct dm_transaction_manager *tm; + struct dm_block *sblock; + + if (create) { + r = dm_tm_create_with_sm(bm, THIN_SUPERBLOCK_LOCATION, + &sb_validator, &tm, &sm, &sblock); + if (r < 0) { + DMERR("tm_create_with_sm failed"); + return r; + } + + data_sm = dm_sm_disk_create(tm, nr_blocks); + if (IS_ERR(data_sm)) { + DMERR("sm_disk_create failed"); + r = PTR_ERR(data_sm); + goto bad; + } + } else { + struct thin_disk_superblock *disk_super = NULL; + size_t space_map_root_offset = + offsetof(struct thin_disk_superblock, metadata_space_map_root); + + r = dm_tm_open_with_sm(bm, THIN_SUPERBLOCK_LOCATION, + &sb_validator, space_map_root_offset, + SPACE_MAP_ROOT_SIZE, &tm, &sm, &sblock); + if (r < 0) { + DMERR("tm_open_with_sm failed"); + return r; + } + + disk_super = dm_block_data(sblock); + data_sm = dm_sm_disk_open(tm, disk_super->data_space_map_root, + sizeof(disk_super->data_space_map_root)); + if (IS_ERR(data_sm)) { + DMERR("sm_disk_open failed"); + r = PTR_ERR(data_sm); + goto bad; + } + } + + + r = dm_tm_unlock(tm, sblock); + if (r < 0) { + DMERR("couldn't unlock superblock"); + goto bad_data_sm; + } + + pmd->bm = bm; + pmd->metadata_sm = sm; + pmd->data_sm = data_sm; + pmd->tm = tm; + pmd->nb_tm = dm_tm_create_non_blocking_clone(tm); + if (!pmd->nb_tm) { + DMERR("could not create clone tm"); + r = -ENOMEM; + goto bad_data_sm; + } + + pmd->info.tm = tm; + pmd->info.levels = 2; + pmd->info.value_type.context = pmd->data_sm; + pmd->info.value_type.size = sizeof(__le64); + pmd->info.value_type.inc = data_block_inc; + pmd->info.value_type.dec = data_block_dec; + pmd->info.value_type.equal = data_block_equal; + + memcpy(&pmd->nb_info, &pmd->info, sizeof(pmd->nb_info)); + pmd->nb_info.tm = pmd->nb_tm; + + pmd->tl_info.tm = tm; + pmd->tl_info.levels = 1; + pmd->tl_info.value_type.context = &pmd->info; + pmd->tl_info.value_type.size = sizeof(__le64); + pmd->tl_info.value_type.inc = subtree_inc; + pmd->tl_info.value_type.dec = subtree_dec; + pmd->tl_info.value_type.equal = subtree_equal; + + pmd->bl_info.tm = tm; + pmd->bl_info.levels = 1; + pmd->bl_info.value_type.context = pmd->data_sm; + pmd->bl_info.value_type.size = sizeof(__le64); + pmd->bl_info.value_type.inc = data_block_inc; + pmd->bl_info.value_type.dec = data_block_dec; + pmd->bl_info.value_type.equal = data_block_equal; + + pmd->details_info.tm = tm; + pmd->details_info.levels = 1; + pmd->details_info.value_type.context = NULL; + pmd->details_info.value_type.size = sizeof(struct disk_device_details); + pmd->details_info.value_type.inc = NULL; + pmd->details_info.value_type.dec = NULL; + pmd->details_info.value_type.equal = NULL; + + pmd->root = 0; + + init_rwsem(&pmd->root_lock); + pmd->time = 0; + pmd->need_commit = 0; + pmd->details_root = 0; + pmd->trans_id = 0; + pmd->flags = 0; + INIT_LIST_HEAD(&pmd->thin_devices); + + return 0; + +bad_data_sm: + dm_sm_destroy(data_sm); +bad: + dm_tm_destroy(tm); + dm_sm_destroy(sm); + + return r; +} + +static int __begin_transaction(struct dm_pool_metadata *pmd) +{ + int r; + u32 features; + struct thin_disk_superblock *disk_super; + struct dm_block *sblock; + + /* + * __maybe_commit_transaction() resets these + */ + WARN_ON(pmd->need_commit); + + /* + * We re-read the superblock every time. Shouldn't need to do this + * really. + */ + r = dm_bm_read_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION, + &sb_validator, &sblock); + if (r) + return r; + + disk_super = dm_block_data(sblock); + pmd->time = le32_to_cpu(disk_super->time); + pmd->root = le64_to_cpu(disk_super->data_mapping_root); + pmd->details_root = le64_to_cpu(disk_super->device_details_root); + pmd->trans_id = le64_to_cpu(disk_super->trans_id); + pmd->flags = le32_to_cpu(disk_super->flags); + pmd->data_block_size = le32_to_cpu(disk_super->data_block_size); + + features = le32_to_cpu(disk_super->incompat_flags) & ~THIN_FEATURE_INCOMPAT_SUPP; + if (features) { + DMERR("could not access metadata due to " + "unsupported optional features (%lx).", + (unsigned long)features); + r = -EINVAL; + goto out; + } + + /* + * Check for read-only metadata to skip the following RDWR checks. + */ + if (get_disk_ro(pmd->bdev->bd_disk)) + goto out; + + features = le32_to_cpu(disk_super->compat_ro_flags) & ~THIN_FEATURE_COMPAT_RO_SUPP; + if (features) { + DMERR("could not access metadata RDWR due to " + "unsupported optional features (%lx).", + (unsigned long)features); + r = -EINVAL; + } + +out: + dm_bm_unlock(sblock); + return r; +} + +static int __write_changed_details(struct dm_pool_metadata *pmd) +{ + int r; + struct dm_thin_device *td, *tmp; + struct disk_device_details details; + uint64_t key; + + list_for_each_entry_safe(td, tmp, &pmd->thin_devices, list) { + if (!td->changed) + continue; + + key = td->id; + + details.mapped_blocks = cpu_to_le64(td->mapped_blocks); + details.transaction_id = cpu_to_le64(td->transaction_id); + details.creation_time = cpu_to_le32(td->creation_time); + details.snapshotted_time = cpu_to_le32(td->snapshotted_time); + __dm_bless_for_disk(&details); + + r = dm_btree_insert(&pmd->details_info, pmd->details_root, + &key, &details, &pmd->details_root); + if (r) + return r; + + if (td->open_count) + td->changed = 0; + else { + list_del(&td->list); + kfree(td); + } + + pmd->need_commit = 1; + } + + return 0; +} + +static int __commit_transaction(struct dm_pool_metadata *pmd) +{ + /* + * FIXME: Associated pool should be made read-only on failure. + */ + int r; + size_t metadata_len, data_len; + struct thin_disk_superblock *disk_super; + struct dm_block *sblock; + + /* + * We need to know if the thin_disk_superblock exceeds a 512-byte sector. + */ + BUILD_BUG_ON(sizeof(struct thin_disk_superblock) > 512); + + r = __write_changed_details(pmd); + if (r < 0) + goto out; + + if (!pmd->need_commit) + goto out; + + r = dm_sm_commit(pmd->data_sm); + if (r < 0) + goto out; + + r = dm_tm_pre_commit(pmd->tm); + if (r < 0) + goto out; + + r = dm_sm_root_size(pmd->metadata_sm, &metadata_len); + if (r < 0) + goto out; + + r = dm_sm_root_size(pmd->metadata_sm, &data_len); + if (r < 0) + goto out; + + r = dm_bm_write_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION, + &sb_validator, &sblock); + if (r) + goto out; + + disk_super = dm_block_data(sblock); + disk_super->time = cpu_to_le32(pmd->time); + disk_super->data_mapping_root = cpu_to_le64(pmd->root); + disk_super->device_details_root = cpu_to_le64(pmd->details_root); + disk_super->trans_id = cpu_to_le64(pmd->trans_id); + disk_super->flags = cpu_to_le32(pmd->flags); + + r = dm_sm_copy_root(pmd->metadata_sm, &disk_super->metadata_space_map_root, + metadata_len); + if (r < 0) + goto out_locked; + + r = dm_sm_copy_root(pmd->data_sm, &disk_super->data_space_map_root, + data_len); + if (r < 0) + goto out_locked; + + r = dm_tm_commit(pmd->tm, sblock); + if (!r) + pmd->need_commit = 0; + +out: + return r; + +out_locked: + dm_bm_unlock(sblock); + return r; +} + +struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev, + sector_t data_block_size) +{ + int r; + struct thin_disk_superblock *disk_super; + struct dm_pool_metadata *pmd; + sector_t bdev_size = i_size_read(bdev->bd_inode) >> SECTOR_SHIFT; + struct dm_block_manager *bm; + int create; + struct dm_block *sblock; + + pmd = kmalloc(sizeof(*pmd), GFP_KERNEL); + if (!pmd) { + DMERR("could not allocate metadata struct"); + return ERR_PTR(-ENOMEM); + } + + /* + * Max hex locks: + * 3 for btree insert + + * 2 for btree lookup used within space map + */ + bm = dm_block_manager_create(bdev, THIN_METADATA_BLOCK_SIZE, + THIN_METADATA_CACHE_SIZE, 5); + if (!bm) { + DMERR("could not create block manager"); + kfree(pmd); + return ERR_PTR(-ENOMEM); + } + + r = superblock_all_zeroes(bm, &create); + if (r) { + dm_block_manager_destroy(bm); + kfree(pmd); + return ERR_PTR(r); + } + + + r = init_pmd(pmd, bm, 0, create); + if (r) { + dm_block_manager_destroy(bm); + kfree(pmd); + return ERR_PTR(r); + } + pmd->bdev = bdev; + + if (!create) { + r = __begin_transaction(pmd); + if (r < 0) + goto bad; + return pmd; + } + + /* + * Create. + */ + r = dm_bm_write_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION, + &sb_validator, &sblock); + if (r) + goto bad; + + disk_super = dm_block_data(sblock); + disk_super->magic = cpu_to_le64(THIN_SUPERBLOCK_MAGIC); + disk_super->version = cpu_to_le32(THIN_VERSION); + disk_super->time = 0; + disk_super->metadata_block_size = cpu_to_le32(THIN_METADATA_BLOCK_SIZE >> SECTOR_SHIFT); + disk_super->metadata_nr_blocks = cpu_to_le64(bdev_size >> SECTOR_TO_BLOCK_SHIFT); + disk_super->data_block_size = cpu_to_le32(data_block_size); + + r = dm_bm_unlock(sblock); + if (r < 0) + goto bad; + + r = dm_btree_empty(&pmd->info, &pmd->root); + if (r < 0) + goto bad; + + r = dm_btree_empty(&pmd->details_info, &pmd->details_root); + if (r < 0) { + DMERR("couldn't create devices root"); + goto bad; + } + + pmd->flags = 0; + pmd->need_commit = 1; + r = dm_pool_commit_metadata(pmd); + if (r < 0) { + DMERR("%s: dm_pool_commit_metadata() failed, error = %d", + __func__, r); + goto bad; + } + + return pmd; + +bad: + if (dm_pool_metadata_close(pmd) < 0) + DMWARN("%s: dm_pool_metadata_close() failed.", __func__); + return ERR_PTR(r); +} + +int dm_pool_metadata_close(struct dm_pool_metadata *pmd) +{ + int r; + unsigned open_devices = 0; + struct dm_thin_device *td, *tmp; + + down_read(&pmd->root_lock); + list_for_each_entry_safe(td, tmp, &pmd->thin_devices, list) { + if (td->open_count) + open_devices++; + else { + list_del(&td->list); + kfree(td); + } + } + up_read(&pmd->root_lock); + + if (open_devices) { + DMERR("attempt to close pmd when %u device(s) are still open", + open_devices); + return -EBUSY; + } + + r = __commit_transaction(pmd); + if (r < 0) + DMWARN("%s: __commit_transaction() failed, error = %d", + __func__, r); + + dm_tm_destroy(pmd->tm); + dm_tm_destroy(pmd->nb_tm); + dm_block_manager_destroy(pmd->bm); + dm_sm_destroy(pmd->metadata_sm); + dm_sm_destroy(pmd->data_sm); + kfree(pmd); + + return 0; +} + +static int __open_device(struct dm_pool_metadata *pmd, + dm_thin_id dev, int create, + struct dm_thin_device **td) +{ + int r, changed = 0; + struct dm_thin_device *td2; + uint64_t key = dev; + struct disk_device_details details_le; + + /* + * Check the device isn't already open. + */ + list_for_each_entry(td2, &pmd->thin_devices, list) + if (td2->id == dev) { + td2->open_count++; + *td = td2; + return 0; + } + + /* + * Check the device exists. + */ + r = dm_btree_lookup(&pmd->details_info, pmd->details_root, + &key, &details_le); + if (r) { + if (r != -ENODATA || !create) + return r; + + changed = 1; + details_le.mapped_blocks = 0; + details_le.transaction_id = cpu_to_le64(pmd->trans_id); + details_le.creation_time = cpu_to_le32(pmd->time); + details_le.snapshotted_time = cpu_to_le32(pmd->time); + } + + *td = kmalloc(sizeof(**td), GFP_NOIO); + if (!*td) + return -ENOMEM; + + (*td)->pmd = pmd; + (*td)->id = dev; + (*td)->open_count = 1; + (*td)->changed = changed; + (*td)->mapped_blocks = le64_to_cpu(details_le.mapped_blocks); + (*td)->transaction_id = le64_to_cpu(details_le.transaction_id); + (*td)->creation_time = le32_to_cpu(details_le.creation_time); + (*td)->snapshotted_time = le32_to_cpu(details_le.snapshotted_time); + + list_add(&(*td)->list, &pmd->thin_devices); + + return 0; +} + +static void __close_device(struct dm_thin_device *td) +{ + --td->open_count; +} + +static int __create_thin(struct dm_pool_metadata *pmd, + dm_thin_id dev) +{ + int r; + dm_block_t dev_root; + uint64_t key = dev; + struct disk_device_details details_le; + struct dm_thin_device *td; + __le64 value; + + r = dm_btree_lookup(&pmd->details_info, pmd->details_root, + &key, &details_le); + if (!r) + return -EEXIST; + + /* + * Create an empty btree for the mappings. + */ + r = dm_btree_empty(&pmd->bl_info, &dev_root); + if (r) + return r; + + /* + * Insert it into the main mapping tree. + */ + value = cpu_to_le64(dev_root); + __dm_bless_for_disk(&value); + r = dm_btree_insert(&pmd->tl_info, pmd->root, &key, &value, &pmd->root); + if (r) { + dm_btree_del(&pmd->bl_info, dev_root); + return r; + } + + r = __open_device(pmd, dev, 1, &td); + if (r) { + __close_device(td); + dm_btree_remove(&pmd->tl_info, pmd->root, &key, &pmd->root); + dm_btree_del(&pmd->bl_info, dev_root); + return r; + } + td->changed = 1; + __close_device(td); + + return r; +} + +int dm_pool_create_thin(struct dm_pool_metadata *pmd, dm_thin_id dev) +{ + int r; + + down_write(&pmd->root_lock); + r = __create_thin(pmd, dev); + up_write(&pmd->root_lock); + + return r; +} + +static int __set_snapshot_details(struct dm_pool_metadata *pmd, + struct dm_thin_device *snap, + dm_thin_id origin, uint32_t time) +{ + int r; + struct dm_thin_device *td; + + r = __open_device(pmd, origin, 0, &td); + if (r) + return r; + + td->changed = 1; + td->snapshotted_time = time; + + snap->mapped_blocks = td->mapped_blocks; + snap->snapshotted_time = time; + __close_device(td); + + return 0; +} + +static int __create_snap(struct dm_pool_metadata *pmd, + dm_thin_id dev, dm_thin_id origin) +{ + int r; + dm_block_t origin_root; + uint64_t key = origin, dev_key = dev; + struct dm_thin_device *td; + struct disk_device_details details_le; + __le64 value; + + /* check this device is unused */ + r = dm_btree_lookup(&pmd->details_info, pmd->details_root, + &dev_key, &details_le); + if (!r) + return -EEXIST; + + /* find the mapping tree for the origin */ + r = dm_btree_lookup(&pmd->tl_info, pmd->root, &key, &value); + if (r) + return r; + origin_root = le64_to_cpu(value); + + /* clone the origin, an inc will do */ + dm_tm_inc(pmd->tm, origin_root); + + /* insert into the main mapping tree */ + value = cpu_to_le64(origin_root); + __dm_bless_for_disk(&value); + key = dev; + r = dm_btree_insert(&pmd->tl_info, pmd->root, &key, &value, &pmd->root); + if (r) { + dm_tm_dec(pmd->tm, origin_root); + return r; + } + + pmd->time++; + + r = __open_device(pmd, dev, 1, &td); + if (r) + goto bad; + + r = __set_snapshot_details(pmd, td, origin, pmd->time); + if (r) + goto bad; + + __close_device(td); + return 0; + +bad: + __close_device(td); + dm_btree_remove(&pmd->tl_info, pmd->root, &key, &pmd->root); + dm_btree_remove(&pmd->details_info, pmd->details_root, + &key, &pmd->details_root); + return r; +} + +int dm_pool_create_snap(struct dm_pool_metadata *pmd, + dm_thin_id dev, + dm_thin_id origin) +{ + int r; + + down_write(&pmd->root_lock); + r = __create_snap(pmd, dev, origin); + up_write(&pmd->root_lock); + + return r; +} + +static int __delete_device(struct dm_pool_metadata *pmd, dm_thin_id dev) +{ + int r; + uint64_t key = dev; + struct dm_thin_device *td; + + /* TODO: failure should mark the transaction invalid */ + r = __open_device(pmd, dev, 0, &td); + if (r) + return r; + + if (td->open_count > 1) { + __close_device(td); + return -EBUSY; + } + + list_del(&td->list); + kfree(td); + r = dm_btree_remove(&pmd->details_info, pmd->details_root, + &key, &pmd->details_root); + if (r) + return r; + + r = dm_btree_remove(&pmd->tl_info, pmd->root, &key, &pmd->root); + if (r) + return r; + + pmd->need_commit = 1; + + return 0; +} + +int dm_pool_delete_thin_device(struct dm_pool_metadata *pmd, + dm_thin_id dev) +{ + int r; + + down_write(&pmd->root_lock); + r = __delete_device(pmd, dev); + up_write(&pmd->root_lock); + + return r; +} + +int dm_pool_set_metadata_transaction_id(struct dm_pool_metadata *pmd, + uint64_t current_id, + uint64_t new_id) +{ + down_write(&pmd->root_lock); + if (pmd->trans_id != current_id) { + up_write(&pmd->root_lock); + DMERR("mismatched transaction id"); + return -EINVAL; + } + + pmd->trans_id = new_id; + pmd->need_commit = 1; + up_write(&pmd->root_lock); + + return 0; +} + +int dm_pool_get_metadata_transaction_id(struct dm_pool_metadata *pmd, + uint64_t *result) +{ + down_read(&pmd->root_lock); + *result = pmd->trans_id; + up_read(&pmd->root_lock); + + return 0; +} + +static int __get_held_metadata_root(struct dm_pool_metadata *pmd, + dm_block_t *result) +{ + int r; + struct thin_disk_superblock *disk_super; + struct dm_block *sblock; + + r = dm_bm_write_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION, + &sb_validator, &sblock); + if (r) + return r; + + disk_super = dm_block_data(sblock); + *result = le64_to_cpu(disk_super->held_root); + + return dm_bm_unlock(sblock); +} + +int dm_pool_get_held_metadata_root(struct dm_pool_metadata *pmd, + dm_block_t *result) +{ + int r; + + down_read(&pmd->root_lock); + r = __get_held_metadata_root(pmd, result); + up_read(&pmd->root_lock); + + return r; +} + +int dm_pool_open_thin_device(struct dm_pool_metadata *pmd, dm_thin_id dev, + struct dm_thin_device **td) +{ + int r; + + down_write(&pmd->root_lock); + r = __open_device(pmd, dev, 0, td); + up_write(&pmd->root_lock); + + return r; +} + +int dm_pool_close_thin_device(struct dm_thin_device *td) +{ + down_write(&td->pmd->root_lock); + __close_device(td); + up_write(&td->pmd->root_lock); + + return 0; +} + +dm_thin_id dm_thin_dev_id(struct dm_thin_device *td) +{ + return td->id; +} + +static int __snapshotted_since(struct dm_thin_device *td, uint32_t time) +{ + return td->snapshotted_time > time; +} + +int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block, + int can_block, struct dm_thin_lookup_result *result) +{ + int r; + uint64_t block_time = 0; + __le64 value; + struct dm_pool_metadata *pmd = td->pmd; + dm_block_t keys[2] = { td->id, block }; + + if (can_block) { + down_read(&pmd->root_lock); + r = dm_btree_lookup(&pmd->info, pmd->root, keys, &value); + if (!r) + block_time = le64_to_cpu(value); + up_read(&pmd->root_lock); + + } else if (down_read_trylock(&pmd->root_lock)) { + r = dm_btree_lookup(&pmd->nb_info, pmd->root, keys, &value); + if (!r) + block_time = le64_to_cpu(value); + up_read(&pmd->root_lock); + + } else + return -EWOULDBLOCK; + + if (!r) { + dm_block_t exception_block; + uint32_t exception_time; + unpack_block_time(block_time, &exception_block, + &exception_time); + result->block = exception_block; + result->shared = __snapshotted_since(td, exception_time); + } + + return r; +} + +static int __insert(struct dm_thin_device *td, dm_block_t block, + dm_block_t data_block) +{ + int r, inserted; + __le64 value; + struct dm_pool_metadata *pmd = td->pmd; + dm_block_t keys[2] = { td->id, block }; + + pmd->need_commit = 1; + value = cpu_to_le64(pack_block_time(data_block, pmd->time)); + __dm_bless_for_disk(&value); + + r = dm_btree_insert_notify(&pmd->info, pmd->root, keys, &value, + &pmd->root, &inserted); + if (r) + return r; + + if (inserted) { + td->mapped_blocks++; + td->changed = 1; + } + + return 0; +} + +int dm_thin_insert_block(struct dm_thin_device *td, dm_block_t block, + dm_block_t data_block) +{ + int r; + + down_write(&td->pmd->root_lock); + r = __insert(td, block, data_block); + up_write(&td->pmd->root_lock); + + return r; +} + +static int __remove(struct dm_thin_device *td, dm_block_t block) +{ + int r; + struct dm_pool_metadata *pmd = td->pmd; + dm_block_t keys[2] = { td->id, block }; + + r = dm_btree_remove(&pmd->info, pmd->root, keys, &pmd->root); + if (r) + return r; + + pmd->need_commit = 1; + + return 0; +} + +int dm_thin_remove_block(struct dm_thin_device *td, dm_block_t block) +{ + int r; + + down_write(&td->pmd->root_lock); + r = __remove(td, block); + up_write(&td->pmd->root_lock); + + return r; +} + +int dm_pool_alloc_data_block(struct dm_pool_metadata *pmd, dm_block_t *result) +{ + int r; + + down_write(&pmd->root_lock); + + r = dm_sm_new_block(pmd->data_sm, result); + pmd->need_commit = 1; + + up_write(&pmd->root_lock); + + return r; +} + +int dm_pool_commit_metadata(struct dm_pool_metadata *pmd) +{ + int r; + + down_write(&pmd->root_lock); + + r = __commit_transaction(pmd); + if (r <= 0) + goto out; + + /* + * Open the next transaction. + */ + r = __begin_transaction(pmd); +out: + up_write(&pmd->root_lock); + return r; +} + +int dm_pool_get_free_block_count(struct dm_pool_metadata *pmd, dm_block_t *result) +{ + int r; + + down_read(&pmd->root_lock); + r = dm_sm_get_nr_free(pmd->data_sm, result); + up_read(&pmd->root_lock); + + return r; +} + +int dm_pool_get_free_metadata_block_count(struct dm_pool_metadata *pmd, + dm_block_t *result) +{ + int r; + + down_read(&pmd->root_lock); + r = dm_sm_get_nr_free(pmd->metadata_sm, result); + up_read(&pmd->root_lock); + + return r; +} + +int dm_pool_get_metadata_dev_size(struct dm_pool_metadata *pmd, + dm_block_t *result) +{ + int r; + + down_read(&pmd->root_lock); + r = dm_sm_get_nr_blocks(pmd->metadata_sm, result); + up_read(&pmd->root_lock); + + return r; +} + +int dm_pool_get_data_block_size(struct dm_pool_metadata *pmd, sector_t *result) +{ + down_read(&pmd->root_lock); + *result = pmd->data_block_size; + up_read(&pmd->root_lock); + + return 0; +} + +int dm_pool_get_data_dev_size(struct dm_pool_metadata *pmd, dm_block_t *result) +{ + int r; + + down_read(&pmd->root_lock); + r = dm_sm_get_nr_blocks(pmd->data_sm, result); + up_read(&pmd->root_lock); + + return r; +} + +int dm_thin_get_mapped_count(struct dm_thin_device *td, dm_block_t *result) +{ + struct dm_pool_metadata *pmd = td->pmd; + + down_read(&pmd->root_lock); + *result = td->mapped_blocks; + up_read(&pmd->root_lock); + + return 0; +} + +static int __highest_block(struct dm_thin_device *td, dm_block_t *result) +{ + int r; + __le64 value_le; + dm_block_t thin_root; + struct dm_pool_metadata *pmd = td->pmd; + + r = dm_btree_lookup(&pmd->tl_info, pmd->root, &td->id, &value_le); + if (r) + return r; + + thin_root = le64_to_cpu(value_le); + + return dm_btree_find_highest_key(&pmd->bl_info, thin_root, result); +} + +int dm_thin_get_highest_mapped_block(struct dm_thin_device *td, + dm_block_t *result) +{ + int r; + struct dm_pool_metadata *pmd = td->pmd; + + down_read(&pmd->root_lock); + r = __highest_block(td, result); + up_read(&pmd->root_lock); + + return r; +} + +static int __resize_data_dev(struct dm_pool_metadata *pmd, dm_block_t new_count) +{ + int r; + dm_block_t old_count; + + r = dm_sm_get_nr_blocks(pmd->data_sm, &old_count); + if (r) + return r; + + if (new_count == old_count) + return 0; + + if (new_count < old_count) { + DMERR("cannot reduce size of data device"); + return -EINVAL; + } + + r = dm_sm_extend(pmd->data_sm, new_count - old_count); + if (!r) + pmd->need_commit = 1; + + return r; +} + +int dm_pool_resize_data_dev(struct dm_pool_metadata *pmd, dm_block_t new_count) +{ + int r; + + down_write(&pmd->root_lock); + r = __resize_data_dev(pmd, new_count); + up_write(&pmd->root_lock); + + return r; +} diff --git a/drivers/md/dm-thin-metadata.h b/drivers/md/dm-thin-metadata.h new file mode 100644 index 00000000000..859c1689687 --- /dev/null +++ b/drivers/md/dm-thin-metadata.h @@ -0,0 +1,156 @@ +/* + * Copyright (C) 2010-2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#ifndef DM_THIN_METADATA_H +#define DM_THIN_METADATA_H + +#include "persistent-data/dm-block-manager.h" + +#define THIN_METADATA_BLOCK_SIZE 4096 + +/*----------------------------------------------------------------*/ + +struct dm_pool_metadata; +struct dm_thin_device; + +/* + * Device identifier + */ +typedef uint64_t dm_thin_id; + +/* + * Reopens or creates a new, empty metadata volume. + */ +struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev, + sector_t data_block_size); + +int dm_pool_metadata_close(struct dm_pool_metadata *pmd); + +/* + * Compat feature flags. Any incompat flags beyond the ones + * specified below will prevent use of the thin metadata. + */ +#define THIN_FEATURE_COMPAT_SUPP 0UL +#define THIN_FEATURE_COMPAT_RO_SUPP 0UL +#define THIN_FEATURE_INCOMPAT_SUPP 0UL + +/* + * Device creation/deletion. + */ +int dm_pool_create_thin(struct dm_pool_metadata *pmd, dm_thin_id dev); + +/* + * An internal snapshot. + * + * You can only snapshot a quiesced origin i.e. one that is either + * suspended or not instanced at all. + */ +int dm_pool_create_snap(struct dm_pool_metadata *pmd, dm_thin_id dev, + dm_thin_id origin); + +/* + * Deletes a virtual device from the metadata. It _is_ safe to call this + * when that device is open. Operations on that device will just start + * failing. You still need to call close() on the device. + */ +int dm_pool_delete_thin_device(struct dm_pool_metadata *pmd, + dm_thin_id dev); + +/* + * Commits _all_ metadata changes: device creation, deletion, mapping + * updates. + */ +int dm_pool_commit_metadata(struct dm_pool_metadata *pmd); + +/* + * Set/get userspace transaction id. + */ +int dm_pool_set_metadata_transaction_id(struct dm_pool_metadata *pmd, + uint64_t current_id, + uint64_t new_id); + +int dm_pool_get_metadata_transaction_id(struct dm_pool_metadata *pmd, + uint64_t *result); + +/* + * Hold/get root for userspace transaction. + */ +int dm_pool_hold_metadata_root(struct dm_pool_metadata *pmd); + +int dm_pool_get_held_metadata_root(struct dm_pool_metadata *pmd, + dm_block_t *result); + +/* + * Actions on a single virtual device. + */ + +/* + * Opening the same device more than once will fail with -EBUSY. + */ +int dm_pool_open_thin_device(struct dm_pool_metadata *pmd, dm_thin_id dev, + struct dm_thin_device **td); + +int dm_pool_close_thin_device(struct dm_thin_device *td); + +dm_thin_id dm_thin_dev_id(struct dm_thin_device *td); + +struct dm_thin_lookup_result { + dm_block_t block; + int shared; +}; + +/* + * Returns: + * -EWOULDBLOCK iff @can_block is set and would block. + * -ENODATA iff that mapping is not present. + * 0 success + */ +int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block, + int can_block, struct dm_thin_lookup_result *result); + +/* + * Obtain an unused block. + */ +int dm_pool_alloc_data_block(struct dm_pool_metadata *pmd, dm_block_t *result); + +/* + * Insert or remove block. + */ +int dm_thin_insert_block(struct dm_thin_device *td, dm_block_t block, + dm_block_t data_block); + +int dm_thin_remove_block(struct dm_thin_device *td, dm_block_t block); + +/* + * Queries. + */ +int dm_thin_get_highest_mapped_block(struct dm_thin_device *td, + dm_block_t *highest_mapped); + +int dm_thin_get_mapped_count(struct dm_thin_device *td, dm_block_t *result); + +int dm_pool_get_free_block_count(struct dm_pool_metadata *pmd, + dm_block_t *result); + +int dm_pool_get_free_metadata_block_count(struct dm_pool_metadata *pmd, + dm_block_t *result); + +int dm_pool_get_metadata_dev_size(struct dm_pool_metadata *pmd, + dm_block_t *result); + +int dm_pool_get_data_block_size(struct dm_pool_metadata *pmd, sector_t *result); + +int dm_pool_get_data_dev_size(struct dm_pool_metadata *pmd, dm_block_t *result); + +/* + * Returns -ENOSPC if the new size is too small and already allocated + * blocks would be lost. + */ +int dm_pool_resize_data_dev(struct dm_pool_metadata *pmd, dm_block_t new_size); + +/*----------------------------------------------------------------*/ + +#endif diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c new file mode 100644 index 00000000000..c3087575fef --- /dev/null +++ b/drivers/md/dm-thin.c @@ -0,0 +1,2428 @@ +/* + * Copyright (C) 2011 Red Hat UK. + * + * This file is released under the GPL. + */ + +#include "dm-thin-metadata.h" + +#include <linux/device-mapper.h> +#include <linux/dm-io.h> +#include <linux/dm-kcopyd.h> +#include <linux/list.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/slab.h> + +#define DM_MSG_PREFIX "thin" + +/* + * Tunable constants + */ +#define ENDIO_HOOK_POOL_SIZE 10240 +#define DEFERRED_SET_SIZE 64 +#define MAPPING_POOL_SIZE 1024 +#define PRISON_CELLS 1024 + +/* + * The block size of the device holding pool data must be + * between 64KB and 1GB. + */ +#define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (64 * 1024 >> SECTOR_SHIFT) +#define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT) + +/* + * The metadata device is currently limited in size. The limitation is + * checked lower down in dm-space-map-metadata, but we also check it here + * so we can fail early. + * + * We have one block of index, which can hold 255 index entries. Each + * index entry contains allocation info about 16k metadata blocks. + */ +#define METADATA_DEV_MAX_SECTORS (255 * (1 << 14) * (THIN_METADATA_BLOCK_SIZE / (1 << SECTOR_SHIFT))) + +/* + * Device id is restricted to 24 bits. + */ +#define MAX_DEV_ID ((1 << 24) - 1) + +/* + * How do we handle breaking sharing of data blocks? + * ================================================= + * + * We use a standard copy-on-write btree to store the mappings for the + * devices (note I'm talking about copy-on-write of the metadata here, not + * the data). When you take an internal snapshot you clone the root node + * of the origin btree. After this there is no concept of an origin or a + * snapshot. They are just two device trees that happen to point to the + * same data blocks. + * + * When we get a write in we decide if it's to a shared data block using + * some timestamp magic. If it is, we have to break sharing. + * + * Let's say we write to a shared block in what was the origin. The + * steps are: + * + * i) plug io further to this physical block. (see bio_prison code). + * + * ii) quiesce any read io to that shared data block. Obviously + * including all devices that share this block. (see deferred_set code) + * + * iii) copy the data block to a newly allocate block. This step can be + * missed out if the io covers the block. (schedule_copy). + * + * iv) insert the new mapping into the origin's btree + * (process_prepared_mappings). This act of inserting breaks some + * sharing of btree nodes between the two devices. Breaking sharing only + * effects the btree of that specific device. Btrees for the other + * devices that share the block never change. The btree for the origin + * device as it was after the last commit is untouched, ie. we're using + * persistent data structures in the functional programming sense. + * + * v) unplug io to this physical block, including the io that triggered + * the breaking of sharing. + * + * Steps (ii) and (iii) occur in parallel. + * + * The metadata _doesn't_ need to be committed before the io continues. We + * get away with this because the io is always written to a _new_ block. + * If there's a crash, then: + * + * - The origin mapping will point to the old origin block (the shared + * one). This will contain the data as it was before the io that triggered + * the breaking of sharing came in. + * + * - The snap mapping still points to the old block. As it would after + * the commit. + * + * The downside of this scheme is the timestamp magic isn't perfect, and + * will continue to think that data block in the snapshot device is shared + * even after the write to the origin has broken sharing. I suspect data + * blocks will typically be shared by many different devices, so we're + * breaking sharing n + 1 times, rather than n, where n is the number of + * devices that reference this data block. At the moment I think the + * benefits far, far outweigh the disadvantages. + */ + +/*----------------------------------------------------------------*/ + +/* + * Sometimes we can't deal with a bio straight away. We put them in prison + * where they can't cause any mischief. Bios are put in a cell identified + * by a key, multiple bios can be in the same cell. When the cell is + * subsequently unlocked the bios become available. + */ +struct bio_prison; + +struct cell_key { + int virtual; + dm_thin_id dev; + dm_block_t block; +}; + +struct cell { + struct hlist_node list; + struct bio_prison *prison; + struct cell_key key; + unsigned count; + struct bio_list bios; +}; + +struct bio_prison { + spinlock_t lock; + mempool_t *cell_pool; + + unsigned nr_buckets; + unsigned hash_mask; + struct hlist_head *cells; +}; + +static uint32_t calc_nr_buckets(unsigned nr_cells) +{ + uint32_t n = 128; + + nr_cells /= 4; + nr_cells = min(nr_cells, 8192u); + + while (n < nr_cells) + n <<= 1; + + return n; +} + +/* + * @nr_cells should be the number of cells you want in use _concurrently_. + * Don't confuse it with the number of distinct keys. + */ +static struct bio_prison *prison_create(unsigned nr_cells) +{ + unsigned i; + uint32_t nr_buckets = calc_nr_buckets(nr_cells); + size_t len = sizeof(struct bio_prison) + + (sizeof(struct hlist_head) * nr_buckets); + struct bio_prison *prison = kmalloc(len, GFP_KERNEL); + + if (!prison) + return NULL; + + spin_lock_init(&prison->lock); + prison->cell_pool = mempool_create_kmalloc_pool(nr_cells, + sizeof(struct cell)); + if (!prison->cell_pool) { + kfree(prison); + return NULL; + } + + prison->nr_buckets = nr_buckets; + prison->hash_mask = nr_buckets - 1; + prison->cells = (struct hlist_head *) (prison + 1); + for (i = 0; i < nr_buckets; i++) + INIT_HLIST_HEAD(prison->cells + i); + + return prison; +} + +static void prison_destroy(struct bio_prison *prison) +{ + mempool_destroy(prison->cell_pool); + kfree(prison); +} + +static uint32_t hash_key(struct bio_prison *prison, struct cell_key *key) +{ + const unsigned long BIG_PRIME = 4294967291UL; + uint64_t hash = key->block * BIG_PRIME; + + return (uint32_t) (hash & prison->hash_mask); +} + +static int keys_equal(struct cell_key *lhs, struct cell_key *rhs) +{ + return (lhs->virtual == rhs->virtual) && + (lhs->dev == rhs->dev) && + (lhs->block == rhs->block); +} + +static struct cell *__search_bucket(struct hlist_head *bucket, + struct cell_key *key) +{ + struct cell *cell; + struct hlist_node *tmp; + + hlist_for_each_entry(cell, tmp, bucket, list) + if (keys_equal(&cell->key, key)) + return cell; + + return NULL; +} + +/* + * This may block if a new cell needs allocating. You must ensure that + * cells will be unlocked even if the calling thread is blocked. + * + * Returns the number of entries in the cell prior to the new addition + * or < 0 on failure. + */ +static int bio_detain(struct bio_prison *prison, struct cell_key *key, + struct bio *inmate, struct cell **ref) +{ + int r; + unsigned long flags; + uint32_t hash = hash_key(prison, key); + struct cell *uninitialized_var(cell), *cell2 = NULL; + + BUG_ON(hash > prison->nr_buckets); + + spin_lock_irqsave(&prison->lock, flags); + cell = __search_bucket(prison->cells + hash, key); + + if (!cell) { + /* + * Allocate a new cell + */ + spin_unlock_irqrestore(&prison->lock, flags); + cell2 = mempool_alloc(prison->cell_pool, GFP_NOIO); + spin_lock_irqsave(&prison->lock, flags); + + /* + * We've been unlocked, so we have to double check that + * nobody else has inserted this cell in the meantime. + */ + cell = __search_bucket(prison->cells + hash, key); + + if (!cell) { + cell = cell2; + cell2 = NULL; + + cell->prison = prison; + memcpy(&cell->key, key, sizeof(cell->key)); + cell->count = 0; + bio_list_init(&cell->bios); + hlist_add_head(&cell->list, prison->cells + hash); + } + } + + r = cell->count++; + bio_list_add(&cell->bios, inmate); + spin_unlock_irqrestore(&prison->lock, flags); + + if (cell2) + mempool_free(cell2, prison->cell_pool); + + *ref = cell; + + return r; +} + +/* + * @inmates must have been initialised prior to this call + */ +static void __cell_release(struct cell *cell, struct bio_list *inmates) +{ + struct bio_prison *prison = cell->prison; + + hlist_del(&cell->list); + + if (inmates) + bio_list_merge(inmates, &cell->bios); + + mempool_free(cell, prison->cell_pool); +} + +static void cell_release(struct cell *cell, struct bio_list *bios) +{ + unsigned long flags; + struct bio_prison *prison = cell->prison; + + spin_lock_irqsave(&prison->lock, flags); + __cell_release(cell, bios); + spin_unlock_irqrestore(&prison->lock, flags); +} + +/* + * There are a couple of places where we put a bio into a cell briefly + * before taking it out again. In these situations we know that no other + * bio may be in the cell. This function releases the cell, and also does + * a sanity check. + */ +static void cell_release_singleton(struct cell *cell, struct bio *bio) +{ + struct bio_prison *prison = cell->prison; + struct bio_list bios; + struct bio *b; + unsigned long flags; + + bio_list_init(&bios); + + spin_lock_irqsave(&prison->lock, flags); + __cell_release(cell, &bios); + spin_unlock_irqrestore(&prison->lock, flags); + + b = bio_list_pop(&bios); + BUG_ON(b != bio); + BUG_ON(!bio_list_empty(&bios)); +} + +static void cell_error(struct cell *cell) +{ + struct bio_prison *prison = cell->prison; + struct bio_list bios; + struct bio *bio; + unsigned long flags; + + bio_list_init(&bios); + + spin_lock_irqsave(&prison->lock, flags); + __cell_release(cell, &bios); + spin_unlock_irqrestore(&prison->lock, flags); + + while ((bio = bio_list_pop(&bios))) + bio_io_error(bio); +} + +/*----------------------------------------------------------------*/ + +/* + * We use the deferred set to keep track of pending reads to shared blocks. + * We do this to ensure the new mapping caused by a write isn't performed + * until these prior reads have completed. Otherwise the insertion of the + * new mapping could free the old block that the read bios are mapped to. + */ + +struct deferred_set; +struct deferred_entry { + struct deferred_set *ds; + unsigned count; + struct list_head work_items; +}; + +struct deferred_set { + spinlock_t lock; + unsigned current_entry; + unsigned sweeper; + struct deferred_entry entries[DEFERRED_SET_SIZE]; +}; + +static void ds_init(struct deferred_set *ds) +{ + int i; + + spin_lock_init(&ds->lock); + ds->current_entry = 0; + ds->sweeper = 0; + for (i = 0; i < DEFERRED_SET_SIZE; i++) { + ds->entries[i].ds = ds; + ds->entries[i].count = 0; + INIT_LIST_HEAD(&ds->entries[i].work_items); + } +} + +static struct deferred_entry *ds_inc(struct deferred_set *ds) +{ + unsigned long flags; + struct deferred_entry *entry; + + spin_lock_irqsave(&ds->lock, flags); + entry = ds->entries + ds->current_entry; + entry->count++; + spin_unlock_irqrestore(&ds->lock, flags); + + return entry; +} + +static unsigned ds_next(unsigned index) +{ + return (index + 1) % DEFERRED_SET_SIZE; +} + +static void __sweep(struct deferred_set *ds, struct list_head *head) +{ + while ((ds->sweeper != ds->current_entry) && + !ds->entries[ds->sweeper].count) { + list_splice_init(&ds->entries[ds->sweeper].work_items, head); + ds->sweeper = ds_next(ds->sweeper); + } + + if ((ds->sweeper == ds->current_entry) && !ds->entries[ds->sweeper].count) + list_splice_init(&ds->entries[ds->sweeper].work_items, head); +} + +static void ds_dec(struct deferred_entry *entry, struct list_head *head) +{ + unsigned long flags; + + spin_lock_irqsave(&entry->ds->lock, flags); + BUG_ON(!entry->count); + --entry->count; + __sweep(entry->ds, head); + spin_unlock_irqrestore(&entry->ds->lock, flags); +} + +/* + * Returns 1 if deferred or 0 if no pending items to delay job. + */ +static int ds_add_work(struct deferred_set *ds, struct list_head *work) +{ + int r = 1; + unsigned long flags; + unsigned next_entry; + + spin_lock_irqsave(&ds->lock, flags); + if ((ds->sweeper == ds->current_entry) && + !ds->entries[ds->current_entry].count) + r = 0; + else { + list_add(work, &ds->entries[ds->current_entry].work_items); + next_entry = ds_next(ds->current_entry); + if (!ds->entries[next_entry].count) + ds->current_entry = next_entry; + } + spin_unlock_irqrestore(&ds->lock, flags); + + return r; +} + +/*----------------------------------------------------------------*/ + +/* + * Key building. + */ +static void build_data_key(struct dm_thin_device *td, + dm_block_t b, struct cell_key *key) +{ + key->virtual = 0; + key->dev = dm_thin_dev_id(td); + key->block = b; +} + +static void build_virtual_key(struct dm_thin_device *td, dm_block_t b, + struct cell_key *key) +{ + key->virtual = 1; + key->dev = dm_thin_dev_id(td); + key->block = b; +} + +/*----------------------------------------------------------------*/ + +/* + * A pool device ties together a metadata device and a data device. It + * also provides the interface for creating and destroying internal + * devices. + */ +struct new_mapping; +struct pool { + struct list_head list; + struct dm_target *ti; /* Only set if a pool target is bound */ + + struct mapped_device *pool_md; + struct block_device *md_dev; + struct dm_pool_metadata *pmd; + + uint32_t sectors_per_block; + unsigned block_shift; + dm_block_t offset_mask; + dm_block_t low_water_blocks; + + unsigned zero_new_blocks:1; + unsigned low_water_triggered:1; /* A dm event has been sent */ + unsigned no_free_space:1; /* A -ENOSPC warning has been issued */ + + struct bio_prison *prison; + struct dm_kcopyd_client *copier; + + struct workqueue_struct *wq; + struct work_struct worker; + + unsigned ref_count; + + spinlock_t lock; + struct bio_list deferred_bios; + struct bio_list deferred_flush_bios; + struct list_head prepared_mappings; + + struct bio_list retry_on_resume_list; + + struct deferred_set ds; /* FIXME: move to thin_c */ + + struct new_mapping *next_mapping; + mempool_t *mapping_pool; + mempool_t *endio_hook_pool; +}; + +/* + * Target context for a pool. + */ +struct pool_c { + struct dm_target *ti; + struct pool *pool; + struct dm_dev *data_dev; + struct dm_dev *metadata_dev; + struct dm_target_callbacks callbacks; + + dm_block_t low_water_blocks; + unsigned zero_new_blocks:1; +}; + +/* + * Target context for a thin. + */ +struct thin_c { + struct dm_dev *pool_dev; + dm_thin_id dev_id; + + struct pool *pool; + struct dm_thin_device *td; +}; + +/*----------------------------------------------------------------*/ + +/* + * A global list of pools that uses a struct mapped_device as a key. + */ +static struct dm_thin_pool_table { + struct mutex mutex; + struct list_head pools; +} dm_thin_pool_table; + +static void pool_table_init(void) +{ + mutex_init(&dm_thin_pool_table.mutex); + INIT_LIST_HEAD(&dm_thin_pool_table.pools); +} + +static void __pool_table_insert(struct pool *pool) +{ + BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); + list_add(&pool->list, &dm_thin_pool_table.pools); +} + +static void __pool_table_remove(struct pool *pool) +{ + BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); + list_del(&pool->list); +} + +static struct pool *__pool_table_lookup(struct mapped_device *md) +{ + struct pool *pool = NULL, *tmp; + + BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); + + list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) { + if (tmp->pool_md == md) { + pool = tmp; + break; + } + } + + return pool; +} + +static struct pool *__pool_table_lookup_metadata_dev(struct block_device *md_dev) +{ + struct pool *pool = NULL, *tmp; + + BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); + + list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) { + if (tmp->md_dev == md_dev) { + pool = tmp; + break; + } + } + + return pool; +} + +/*----------------------------------------------------------------*/ + +static void __requeue_bio_list(struct thin_c *tc, struct bio_list *master) +{ + struct bio *bio; + struct bio_list bios; + + bio_list_init(&bios); + bio_list_merge(&bios, master); + bio_list_init(master); + + while ((bio = bio_list_pop(&bios))) { + if (dm_get_mapinfo(bio)->ptr == tc) + bio_endio(bio, DM_ENDIO_REQUEUE); + else + bio_list_add(master, bio); + } +} + +static void requeue_io(struct thin_c *tc) +{ + struct pool *pool = tc->pool; + unsigned long flags; + + spin_lock_irqsave(&pool->lock, flags); + __requeue_bio_list(tc, &pool->deferred_bios); + __requeue_bio_list(tc, &pool->retry_on_resume_list); + spin_unlock_irqrestore(&pool->lock, flags); +} + +/* + * This section of code contains the logic for processing a thin device's IO. + * Much of the code depends on pool object resources (lists, workqueues, etc) + * but most is exclusively called from the thin target rather than the thin-pool + * target. + */ + +static dm_block_t get_bio_block(struct thin_c *tc, struct bio *bio) +{ + return bio->bi_sector >> tc->pool->block_shift; +} + +static void remap(struct thin_c *tc, struct bio *bio, dm_block_t block) +{ + struct pool *pool = tc->pool; + + bio->bi_bdev = tc->pool_dev->bdev; + bio->bi_sector = (block << pool->block_shift) + + (bio->bi_sector & pool->offset_mask); +} + +static void remap_and_issue(struct thin_c *tc, struct bio *bio, + dm_block_t block) +{ + struct pool *pool = tc->pool; + unsigned long flags; + + remap(tc, bio, block); + + /* + * Batch together any FUA/FLUSH bios we find and then issue + * a single commit for them in process_deferred_bios(). + */ + if (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) { + spin_lock_irqsave(&pool->lock, flags); + bio_list_add(&pool->deferred_flush_bios, bio); + spin_unlock_irqrestore(&pool->lock, flags); + } else + generic_make_request(bio); +} + +/* + * wake_worker() is used when new work is queued and when pool_resume is + * ready to continue deferred IO processing. + */ +static void wake_worker(struct pool *pool) +{ + queue_work(pool->wq, &pool->worker); +} + +/*----------------------------------------------------------------*/ + +/* + * Bio endio functions. + */ +struct endio_hook { + struct thin_c *tc; + bio_end_io_t *saved_bi_end_io; + struct deferred_entry *entry; +}; + +struct new_mapping { + struct list_head list; + + int prepared; + + struct thin_c *tc; + dm_block_t virt_block; + dm_block_t data_block; + struct cell *cell; + int err; + + /* + * If the bio covers the whole area of a block then we can avoid + * zeroing or copying. Instead this bio is hooked. The bio will + * still be in the cell, so care has to be taken to avoid issuing + * the bio twice. + */ + struct bio *bio; + bio_end_io_t *saved_bi_end_io; +}; + +static void __maybe_add_mapping(struct new_mapping *m) +{ + struct pool *pool = m->tc->pool; + + if (list_empty(&m->list) && m->prepared) { + list_add(&m->list, &pool->prepared_mappings); + wake_worker(pool); + } +} + +static void copy_complete(int read_err, unsigned long write_err, void *context) +{ + unsigned long flags; + struct new_mapping *m = context; + struct pool *pool = m->tc->pool; + + m->err = read_err || write_err ? -EIO : 0; + + spin_lock_irqsave(&pool->lock, flags); + m->prepared = 1; + __maybe_add_mapping(m); + spin_unlock_irqrestore(&pool->lock, flags); +} + +static void overwrite_endio(struct bio *bio, int err) +{ + unsigned long flags; + struct new_mapping *m = dm_get_mapinfo(bio)->ptr; + struct pool *pool = m->tc->pool; + + m->err = err; + + spin_lock_irqsave(&pool->lock, flags); + m->prepared = 1; + __maybe_add_mapping(m); + spin_unlock_irqrestore(&pool->lock, flags); +} + +static void shared_read_endio(struct bio *bio, int err) +{ + struct list_head mappings; + struct new_mapping *m, *tmp; + struct endio_hook *h = dm_get_mapinfo(bio)->ptr; + unsigned long flags; + struct pool *pool = h->tc->pool; + + bio->bi_end_io = h->saved_bi_end_io; + bio_endio(bio, err); + + INIT_LIST_HEAD(&mappings); + ds_dec(h->entry, &mappings); + + spin_lock_irqsave(&pool->lock, flags); + list_for_each_entry_safe(m, tmp, &mappings, list) { + list_del(&m->list); + INIT_LIST_HEAD(&m->list); + __maybe_add_mapping(m); + } + spin_unlock_irqrestore(&pool->lock, flags); + + mempool_free(h, pool->endio_hook_pool); +} + +/*----------------------------------------------------------------*/ + +/* + * Workqueue. + */ + +/* + * Prepared mapping jobs. + */ + +/* + * This sends the bios in the cell back to the deferred_bios list. + */ +static void cell_defer(struct thin_c *tc, struct cell *cell, + dm_block_t data_block) +{ + struct pool *pool = tc->pool; + unsigned long flags; + + spin_lock_irqsave(&pool->lock, flags); + cell_release(cell, &pool->deferred_bios); + spin_unlock_irqrestore(&tc->pool->lock, flags); + + wake_worker(pool); +} + +/* + * Same as cell_defer above, except it omits one particular detainee, + * a write bio that covers the block and has already been processed. + */ +static void cell_defer_except(struct thin_c *tc, struct cell *cell, + struct bio *exception) +{ + struct bio_list bios; + struct bio *bio; + struct pool *pool = tc->pool; + unsigned long flags; + + bio_list_init(&bios); + cell_release(cell, &bios); + + spin_lock_irqsave(&pool->lock, flags); + while ((bio = bio_list_pop(&bios))) + if (bio != exception) + bio_list_add(&pool->deferred_bios, bio); + spin_unlock_irqrestore(&pool->lock, flags); + + wake_worker(pool); +} + +static void process_prepared_mapping(struct new_mapping *m) +{ + struct thin_c *tc = m->tc; + struct bio *bio; + int r; + + bio = m->bio; + if (bio) + bio->bi_end_io = m->saved_bi_end_io; + + if (m->err) { + cell_error(m->cell); + return; + } + + /* + * Commit the prepared block into the mapping btree. + * Any I/O for this block arriving after this point will get + * remapped to it directly. + */ + r = dm_thin_insert_block(tc->td, m->virt_block, m->data_block); + if (r) { + DMERR("dm_thin_insert_block() failed"); + cell_error(m->cell); + return; + } + + /* + * Release any bios held while the block was being provisioned. + * If we are processing a write bio that completely covers the block, + * we already processed it so can ignore it now when processing + * the bios in the cell. + */ + if (bio) { + cell_defer_except(tc, m->cell, bio); + bio_endio(bio, 0); + } else + cell_defer(tc, m->cell, m->data_block); + + list_del(&m->list); + mempool_free(m, tc->pool->mapping_pool); +} + +static void process_prepared_mappings(struct pool *pool) +{ + unsigned long flags; + struct list_head maps; + struct new_mapping *m, *tmp; + + INIT_LIST_HEAD(&maps); + spin_lock_irqsave(&pool->lock, flags); + list_splice_init(&pool->prepared_mappings, &maps); + spin_unlock_irqrestore(&pool->lock, flags); + + list_for_each_entry_safe(m, tmp, &maps, list) + process_prepared_mapping(m); +} + +/* + * Deferred bio jobs. + */ +static int io_overwrites_block(struct pool *pool, struct bio *bio) +{ + return ((bio_data_dir(bio) == WRITE) && + !(bio->bi_sector & pool->offset_mask)) && + (bio->bi_size == (pool->sectors_per_block << SECTOR_SHIFT)); +} + +static void save_and_set_endio(struct bio *bio, bio_end_io_t **save, + bio_end_io_t *fn) +{ + *save = bio->bi_end_io; + bio->bi_end_io = fn; +} + +static int ensure_next_mapping(struct pool *pool) +{ + if (pool->next_mapping) + return 0; + + pool->next_mapping = mempool_alloc(pool->mapping_pool, GFP_ATOMIC); + + return pool->next_mapping ? 0 : -ENOMEM; +} + +static struct new_mapping *get_next_mapping(struct pool *pool) +{ + struct new_mapping *r = pool->next_mapping; + + BUG_ON(!pool->next_mapping); + + pool->next_mapping = NULL; + + return r; +} + +static void schedule_copy(struct thin_c *tc, dm_block_t virt_block, + dm_block_t data_origin, dm_block_t data_dest, + struct cell *cell, struct bio *bio) +{ + int r; + struct pool *pool = tc->pool; + struct new_mapping *m = get_next_mapping(pool); + + INIT_LIST_HEAD(&m->list); + m->prepared = 0; + m->tc = tc; + m->virt_block = virt_block; + m->data_block = data_dest; + m->cell = cell; + m->err = 0; + m->bio = NULL; + + ds_add_work(&pool->ds, &m->list); + + /* + * IO to pool_dev remaps to the pool target's data_dev. + * + * If the whole block of data is being overwritten, we can issue the + * bio immediately. Otherwise we use kcopyd to clone the data first. + */ + if (io_overwrites_block(pool, bio)) { + m->bio = bio; + save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio); + dm_get_mapinfo(bio)->ptr = m; + remap_and_issue(tc, bio, data_dest); + } else { + struct dm_io_region from, to; + + from.bdev = tc->pool_dev->bdev; + from.sector = data_origin * pool->sectors_per_block; + from.count = pool->sectors_per_block; + + to.bdev = tc->pool_dev->bdev; + to.sector = data_dest * pool->sectors_per_block; + to.count = pool->sectors_per_block; + + r = dm_kcopyd_copy(pool->copier, &from, 1, &to, + 0, copy_complete, m); + if (r < 0) { + mempool_free(m, pool->mapping_pool); + DMERR("dm_kcopyd_copy() failed"); + cell_error(cell); + } + } +} + +static void schedule_zero(struct thin_c *tc, dm_block_t virt_block, + dm_block_t data_block, struct cell *cell, + struct bio *bio) +{ + struct pool *pool = tc->pool; + struct new_mapping *m = get_next_mapping(pool); + + INIT_LIST_HEAD(&m->list); + m->prepared = 0; + m->tc = tc; + m->virt_block = virt_block; + m->data_block = data_block; + m->cell = cell; + m->err = 0; + m->bio = NULL; + + /* + * If the whole block of data is being overwritten or we are not + * zeroing pre-existing data, we can issue the bio immediately. + * Otherwise we use kcopyd to zero the data first. + */ + if (!pool->zero_new_blocks) + process_prepared_mapping(m); + + else if (io_overwrites_block(pool, bio)) { + m->bio = bio; + save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio); + dm_get_mapinfo(bio)->ptr = m; + remap_and_issue(tc, bio, data_block); + + } else { + int r; + struct dm_io_region to; + + to.bdev = tc->pool_dev->bdev; + to.sector = data_block * pool->sectors_per_block; + to.count = pool->sectors_per_block; + + r = dm_kcopyd_zero(pool->copier, 1, &to, 0, copy_complete, m); + if (r < 0) { + mempool_free(m, pool->mapping_pool); + DMERR("dm_kcopyd_zero() failed"); + cell_error(cell); + } + } +} + +static int alloc_data_block(struct thin_c *tc, dm_block_t *result) +{ + int r; + dm_block_t free_blocks; + unsigned long flags; + struct pool *pool = tc->pool; + + r = dm_pool_get_free_block_count(pool->pmd, &free_blocks); + if (r) + return r; + + if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) { + DMWARN("%s: reached low water mark, sending event.", + dm_device_name(pool->pool_md)); + spin_lock_irqsave(&pool->lock, flags); + pool->low_water_triggered = 1; + spin_unlock_irqrestore(&pool->lock, flags); + dm_table_event(pool->ti->table); + } + + if (!free_blocks) { + if (pool->no_free_space) + return -ENOSPC; + else { + /* + * Try to commit to see if that will free up some + * more space. + */ + r = dm_pool_commit_metadata(pool->pmd); + if (r) { + DMERR("%s: dm_pool_commit_metadata() failed, error = %d", + __func__, r); + return r; + } + + r = dm_pool_get_free_block_count(pool->pmd, &free_blocks); + if (r) + return r; + + /* + * If we still have no space we set a flag to avoid + * doing all this checking and return -ENOSPC. + */ + if (!free_blocks) { + DMWARN("%s: no free space available.", + dm_device_name(pool->pool_md)); + spin_lock_irqsave(&pool->lock, flags); + pool->no_free_space = 1; + spin_unlock_irqrestore(&pool->lock, flags); + return -ENOSPC; + } + } + } + + r = dm_pool_alloc_data_block(pool->pmd, result); + if (r) + return r; + + return 0; +} + +/* + * If we have run out of space, queue bios until the device is + * resumed, presumably after having been reloaded with more space. + */ +static void retry_on_resume(struct bio *bio) +{ + struct thin_c *tc = dm_get_mapinfo(bio)->ptr; + struct pool *pool = tc->pool; + unsigned long flags; + + spin_lock_irqsave(&pool->lock, flags); + bio_list_add(&pool->retry_on_resume_list, bio); + spin_unlock_irqrestore(&pool->lock, flags); +} + +static void no_space(struct cell *cell) +{ + struct bio *bio; + struct bio_list bios; + + bio_list_init(&bios); + cell_release(cell, &bios); + + while ((bio = bio_list_pop(&bios))) + retry_on_resume(bio); +} + +static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block, + struct cell_key *key, + struct dm_thin_lookup_result *lookup_result, + struct cell *cell) +{ + int r; + dm_block_t data_block; + + r = alloc_data_block(tc, &data_block); + switch (r) { + case 0: + schedule_copy(tc, block, lookup_result->block, + data_block, cell, bio); + break; + + case -ENOSPC: + no_space(cell); + break; + + default: + DMERR("%s: alloc_data_block() failed, error = %d", __func__, r); + cell_error(cell); + break; + } +} + +static void process_shared_bio(struct thin_c *tc, struct bio *bio, + dm_block_t block, + struct dm_thin_lookup_result *lookup_result) +{ + struct cell *cell; + struct pool *pool = tc->pool; + struct cell_key key; + + /* + * If cell is already occupied, then sharing is already in the process + * of being broken so we have nothing further to do here. + */ + build_data_key(tc->td, lookup_result->block, &key); + if (bio_detain(pool->prison, &key, bio, &cell)) + return; + + if (bio_data_dir(bio) == WRITE) + break_sharing(tc, bio, block, &key, lookup_result, cell); + else { + struct endio_hook *h; + h = mempool_alloc(pool->endio_hook_pool, GFP_NOIO); + + h->tc = tc; + h->entry = ds_inc(&pool->ds); + save_and_set_endio(bio, &h->saved_bi_end_io, shared_read_endio); + dm_get_mapinfo(bio)->ptr = h; + + cell_release_singleton(cell, bio); + remap_and_issue(tc, bio, lookup_result->block); + } +} + +static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block, + struct cell *cell) +{ + int r; + dm_block_t data_block; + + /* + * Remap empty bios (flushes) immediately, without provisioning. + */ + if (!bio->bi_size) { + cell_release_singleton(cell, bio); + remap_and_issue(tc, bio, 0); + return; + } + + /* + * Fill read bios with zeroes and complete them immediately. + */ + if (bio_data_dir(bio) == READ) { + zero_fill_bio(bio); + cell_release_singleton(cell, bio); + bio_endio(bio, 0); + return; + } + + r = alloc_data_block(tc, &data_block); + switch (r) { + case 0: + schedule_zero(tc, block, data_block, cell, bio); + break; + + case -ENOSPC: + no_space(cell); + break; + + default: + DMERR("%s: alloc_data_block() failed, error = %d", __func__, r); + cell_error(cell); + break; + } +} + +static void process_bio(struct thin_c *tc, struct bio *bio) +{ + int r; + dm_block_t block = get_bio_block(tc, bio); + struct cell *cell; + struct cell_key key; + struct dm_thin_lookup_result lookup_result; + + /* + * If cell is already occupied, then the block is already + * being provisioned so we have nothing further to do here. + */ + build_virtual_key(tc->td, block, &key); + if (bio_detain(tc->pool->prison, &key, bio, &cell)) + return; + + r = dm_thin_find_block(tc->td, block, 1, &lookup_result); + switch (r) { + case 0: + /* + * We can release this cell now. This thread is the only + * one that puts bios into a cell, and we know there were + * no preceding bios. + */ + /* + * TODO: this will probably have to change when discard goes + * back in. + */ + cell_release_singleton(cell, bio); + + if (lookup_result.shared) + process_shared_bio(tc, bio, block, &lookup_result); + else + remap_and_issue(tc, bio, lookup_result.block); + break; + + case -ENODATA: + provision_block(tc, bio, block, cell); + break; + + default: + DMERR("dm_thin_find_block() failed, error = %d", r); + bio_io_error(bio); + break; + } +} + +static void process_deferred_bios(struct pool *pool) +{ + unsigned long flags; + struct bio *bio; + struct bio_list bios; + int r; + + bio_list_init(&bios); + + spin_lock_irqsave(&pool->lock, flags); + bio_list_merge(&bios, &pool->deferred_bios); + bio_list_init(&pool->deferred_bios); + spin_unlock_irqrestore(&pool->lock, flags); + + while ((bio = bio_list_pop(&bios))) { + struct thin_c *tc = dm_get_mapinfo(bio)->ptr; + /* + * If we've got no free new_mapping structs, and processing + * this bio might require one, we pause until there are some + * prepared mappings to process. + */ + if (ensure_next_mapping(pool)) { + spin_lock_irqsave(&pool->lock, flags); + bio_list_merge(&pool->deferred_bios, &bios); + spin_unlock_irqrestore(&pool->lock, flags); + + break; + } + process_bio(tc, bio); + } + + /* + * If there are any deferred flush bios, we must commit + * the metadata before issuing them. + */ + bio_list_init(&bios); + spin_lock_irqsave(&pool->lock, flags); + bio_list_merge(&bios, &pool->deferred_flush_bios); + bio_list_init(&pool->deferred_flush_bios); + spin_unlock_irqrestore(&pool->lock, flags); + + if (bio_list_empty(&bios)) + return; + + r = dm_pool_commit_metadata(pool->pmd); + if (r) { + DMERR("%s: dm_pool_commit_metadata() failed, error = %d", + __func__, r); + while ((bio = bio_list_pop(&bios))) + bio_io_error(bio); + return; + } + + while ((bio = bio_list_pop(&bios))) + generic_make_request(bio); +} + +static void do_worker(struct work_struct *ws) +{ + struct pool *pool = container_of(ws, struct pool, worker); + + process_prepared_mappings(pool); + process_deferred_bios(pool); +} + +/*----------------------------------------------------------------*/ + +/* + * Mapping functions. + */ + +/* + * Called only while mapping a thin bio to hand it over to the workqueue. + */ +static void thin_defer_bio(struct thin_c *tc, struct bio *bio) +{ + unsigned long flags; + struct pool *pool = tc->pool; + + spin_lock_irqsave(&pool->lock, flags); + bio_list_add(&pool->deferred_bios, bio); + spin_unlock_irqrestore(&pool->lock, flags); + + wake_worker(pool); +} + +/* + * Non-blocking function called from the thin target's map function. + */ +static int thin_bio_map(struct dm_target *ti, struct bio *bio, + union map_info *map_context) +{ + int r; + struct thin_c *tc = ti->private; + dm_block_t block = get_bio_block(tc, bio); + struct dm_thin_device *td = tc->td; + struct dm_thin_lookup_result result; + + /* + * Save the thin context for easy access from the deferred bio later. + */ + map_context->ptr = tc; + + if (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) { + thin_defer_bio(tc, bio); + return DM_MAPIO_SUBMITTED; + } + + r = dm_thin_find_block(td, block, 0, &result); + + /* + * Note that we defer readahead too. + */ + switch (r) { + case 0: + if (unlikely(result.shared)) { + /* + * We have a race condition here between the + * result.shared value returned by the lookup and + * snapshot creation, which may cause new + * sharing. + * + * To avoid this always quiesce the origin before + * taking the snap. You want to do this anyway to + * ensure a consistent application view + * (i.e. lockfs). + * + * More distant ancestors are irrelevant. The + * shared flag will be set in their case. + */ + thin_defer_bio(tc, bio); + r = DM_MAPIO_SUBMITTED; + } else { + remap(tc, bio, result.block); + r = DM_MAPIO_REMAPPED; + } + break; + + case -ENODATA: + /* + * In future, the failed dm_thin_find_block above could + * provide the hint to load the metadata into cache. + */ + case -EWOULDBLOCK: + thin_defer_bio(tc, bio); + r = DM_MAPIO_SUBMITTED; + break; + } + + return r; +} + +static int pool_is_congested(struct dm_target_callbacks *cb, int bdi_bits) +{ + int r; + unsigned long flags; + struct pool_c *pt = container_of(cb, struct pool_c, callbacks); + + spin_lock_irqsave(&pt->pool->lock, flags); + r = !bio_list_empty(&pt->pool->retry_on_resume_list); + spin_unlock_irqrestore(&pt->pool->lock, flags); + + if (!r) { + struct request_queue *q = bdev_get_queue(pt->data_dev->bdev); + r = bdi_congested(&q->backing_dev_info, bdi_bits); + } + + return r; +} + +static void __requeue_bios(struct pool *pool) +{ + bio_list_merge(&pool->deferred_bios, &pool->retry_on_resume_list); + bio_list_init(&pool->retry_on_resume_list); +} + +/*---------------------------------------------------------------- + * Binding of control targets to a pool object + *--------------------------------------------------------------*/ +static int bind_control_target(struct pool *pool, struct dm_target *ti) +{ + struct pool_c *pt = ti->private; + + pool->ti = ti; + pool->low_water_blocks = pt->low_water_blocks; + pool->zero_new_blocks = pt->zero_new_blocks; + + return 0; +} + +static void unbind_control_target(struct pool *pool, struct dm_target *ti) +{ + if (pool->ti == ti) + pool->ti = NULL; +} + +/*---------------------------------------------------------------- + * Pool creation + *--------------------------------------------------------------*/ +static void __pool_destroy(struct pool *pool) +{ + __pool_table_remove(pool); + + if (dm_pool_metadata_close(pool->pmd) < 0) + DMWARN("%s: dm_pool_metadata_close() failed.", __func__); + + prison_destroy(pool->prison); + dm_kcopyd_client_destroy(pool->copier); + + if (pool->wq) + destroy_workqueue(pool->wq); + + if (pool->next_mapping) + mempool_free(pool->next_mapping, pool->mapping_pool); + mempool_destroy(pool->mapping_pool); + mempool_destroy(pool->endio_hook_pool); + kfree(pool); +} + +static struct pool *pool_create(struct mapped_device *pool_md, + struct block_device *metadata_dev, + unsigned long block_size, char **error) +{ + int r; + void *err_p; + struct pool *pool; + struct dm_pool_metadata *pmd; + + pmd = dm_pool_metadata_open(metadata_dev, block_size); + if (IS_ERR(pmd)) { + *error = "Error creating metadata object"; + return (struct pool *)pmd; + } + + pool = kmalloc(sizeof(*pool), GFP_KERNEL); + if (!pool) { + *error = "Error allocating memory for pool"; + err_p = ERR_PTR(-ENOMEM); + goto bad_pool; + } + + pool->pmd = pmd; + pool->sectors_per_block = block_size; + pool->block_shift = ffs(block_size) - 1; + pool->offset_mask = block_size - 1; + pool->low_water_blocks = 0; + pool->zero_new_blocks = 1; + pool->prison = prison_create(PRISON_CELLS); + if (!pool->prison) { + *error = "Error creating pool's bio prison"; + err_p = ERR_PTR(-ENOMEM); + goto bad_prison; + } + + pool->copier = dm_kcopyd_client_create(); + if (IS_ERR(pool->copier)) { + r = PTR_ERR(pool->copier); + *error = "Error creating pool's kcopyd client"; + err_p = ERR_PTR(r); + goto bad_kcopyd_client; + } + + /* + * Create singlethreaded workqueue that will service all devices + * that use this metadata. + */ + pool->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM); + if (!pool->wq) { + *error = "Error creating pool's workqueue"; + err_p = ERR_PTR(-ENOMEM); + goto bad_wq; + } + + INIT_WORK(&pool->worker, do_worker); + spin_lock_init(&pool->lock); + bio_list_init(&pool->deferred_bios); + bio_list_init(&pool->deferred_flush_bios); + INIT_LIST_HEAD(&pool->prepared_mappings); + pool->low_water_triggered = 0; + pool->no_free_space = 0; + bio_list_init(&pool->retry_on_resume_list); + ds_init(&pool->ds); + + pool->next_mapping = NULL; + pool->mapping_pool = + mempool_create_kmalloc_pool(MAPPING_POOL_SIZE, sizeof(struct new_mapping)); + if (!pool->mapping_pool) { + *error = "Error creating pool's mapping mempool"; + err_p = ERR_PTR(-ENOMEM); + goto bad_mapping_pool; + } + + pool->endio_hook_pool = + mempool_create_kmalloc_pool(ENDIO_HOOK_POOL_SIZE, sizeof(struct endio_hook)); + if (!pool->endio_hook_pool) { + *error = "Error creating pool's endio_hook mempool"; + err_p = ERR_PTR(-ENOMEM); + goto bad_endio_hook_pool; + } + pool->ref_count = 1; + pool->pool_md = pool_md; + pool->md_dev = metadata_dev; + __pool_table_insert(pool); + + return pool; + +bad_endio_hook_pool: + mempool_destroy(pool->mapping_pool); +bad_mapping_pool: + destroy_workqueue(pool->wq); +bad_wq: + dm_kcopyd_client_destroy(pool->copier); +bad_kcopyd_client: + prison_destroy(pool->prison); +bad_prison: + kfree(pool); +bad_pool: + if (dm_pool_metadata_close(pmd)) + DMWARN("%s: dm_pool_metadata_close() failed.", __func__); + + return err_p; +} + +static void __pool_inc(struct pool *pool) +{ + BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); + pool->ref_count++; +} + +static void __pool_dec(struct pool *pool) +{ + BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); + BUG_ON(!pool->ref_count); + if (!--pool->ref_count) + __pool_destroy(pool); +} + +static struct pool *__pool_find(struct mapped_device *pool_md, + struct block_device *metadata_dev, + unsigned long block_size, char **error) +{ + struct pool *pool = __pool_table_lookup_metadata_dev(metadata_dev); + + if (pool) { + if (pool->pool_md != pool_md) + return ERR_PTR(-EBUSY); + __pool_inc(pool); + + } else { + pool = __pool_table_lookup(pool_md); + if (pool) { + if (pool->md_dev != metadata_dev) + return ERR_PTR(-EINVAL); + __pool_inc(pool); + + } else + pool = pool_create(pool_md, metadata_dev, block_size, error); + } + + return pool; +} + +/*---------------------------------------------------------------- + * Pool target methods + *--------------------------------------------------------------*/ +static void pool_dtr(struct dm_target *ti) +{ + struct pool_c *pt = ti->private; + + mutex_lock(&dm_thin_pool_table.mutex); + + unbind_control_target(pt->pool, ti); + __pool_dec(pt->pool); + dm_put_device(ti, pt->metadata_dev); + dm_put_device(ti, pt->data_dev); + kfree(pt); + + mutex_unlock(&dm_thin_pool_table.mutex); +} + +struct pool_features { + unsigned zero_new_blocks:1; +}; + +static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf, + struct dm_target *ti) +{ + int r; + unsigned argc; + const char *arg_name; + + static struct dm_arg _args[] = { + {0, 1, "Invalid number of pool feature arguments"}, + }; + + /* + * No feature arguments supplied. + */ + if (!as->argc) + return 0; + + r = dm_read_arg_group(_args, as, &argc, &ti->error); + if (r) + return -EINVAL; + + while (argc && !r) { + arg_name = dm_shift_arg(as); + argc--; + + if (!strcasecmp(arg_name, "skip_block_zeroing")) { + pf->zero_new_blocks = 0; + continue; + } + + ti->error = "Unrecognised pool feature requested"; + r = -EINVAL; + } + + return r; +} + +/* + * thin-pool <metadata dev> <data dev> + * <data block size (sectors)> + * <low water mark (blocks)> + * [<#feature args> [<arg>]*] + * + * Optional feature arguments are: + * skip_block_zeroing: skips the zeroing of newly-provisioned blocks. + */ +static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv) +{ + int r; + struct pool_c *pt; + struct pool *pool; + struct pool_features pf; + struct dm_arg_set as; + struct dm_dev *data_dev; + unsigned long block_size; + dm_block_t low_water_blocks; + struct dm_dev *metadata_dev; + sector_t metadata_dev_size; + + /* + * FIXME Remove validation from scope of lock. + */ + mutex_lock(&dm_thin_pool_table.mutex); + + if (argc < 4) { + ti->error = "Invalid argument count"; + r = -EINVAL; + goto out_unlock; + } + as.argc = argc; + as.argv = argv; + + r = dm_get_device(ti, argv[0], FMODE_READ | FMODE_WRITE, &metadata_dev); + if (r) { + ti->error = "Error opening metadata block device"; + goto out_unlock; + } + + metadata_dev_size = i_size_read(metadata_dev->bdev->bd_inode) >> SECTOR_SHIFT; + if (metadata_dev_size > METADATA_DEV_MAX_SECTORS) { + ti->error = "Metadata device is too large"; + r = -EINVAL; + goto out_metadata; + } + + r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &data_dev); + if (r) { + ti->error = "Error getting data device"; + goto out_metadata; + } + + if (kstrtoul(argv[2], 10, &block_size) || !block_size || + block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS || + block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS || + !is_power_of_2(block_size)) { + ti->error = "Invalid block size"; + r = -EINVAL; + goto out; + } + + if (kstrtoull(argv[3], 10, (unsigned long long *)&low_water_blocks)) { + ti->error = "Invalid low water mark"; + r = -EINVAL; + goto out; + } + + /* + * Set default pool features. + */ + memset(&pf, 0, sizeof(pf)); + pf.zero_new_blocks = 1; + + dm_consume_args(&as, 4); + r = parse_pool_features(&as, &pf, ti); + if (r) + goto out; + + pt = kzalloc(sizeof(*pt), GFP_KERNEL); + if (!pt) { + r = -ENOMEM; + goto out; + } + + pool = __pool_find(dm_table_get_md(ti->table), metadata_dev->bdev, + block_size, &ti->error); + if (IS_ERR(pool)) { + r = PTR_ERR(pool); + goto out_free_pt; + } + + pt->pool = pool; + pt->ti = ti; + pt->metadata_dev = metadata_dev; + pt->data_dev = data_dev; + pt->low_water_blocks = low_water_blocks; + pt->zero_new_blocks = pf.zero_new_blocks; + ti->num_flush_requests = 1; + ti->num_discard_requests = 0; + ti->private = pt; + + pt->callbacks.congested_fn = pool_is_congested; + dm_table_add_target_callbacks(ti->table, &pt->callbacks); + + mutex_unlock(&dm_thin_pool_table.mutex); + + return 0; + +out_free_pt: + kfree(pt); +out: + dm_put_device(ti, data_dev); +out_metadata: + dm_put_device(ti, metadata_dev); +out_unlock: + mutex_unlock(&dm_thin_pool_table.mutex); + + return r; +} + +static int pool_map(struct dm_target *ti, struct bio *bio, + union map_info *map_context) +{ + int r; + struct pool_c *pt = ti->private; + struct pool *pool = pt->pool; + unsigned long flags; + + /* + * As this is a singleton target, ti->begin is always zero. + */ + spin_lock_irqsave(&pool->lock, flags); + bio->bi_bdev = pt->data_dev->bdev; + r = DM_MAPIO_REMAPPED; + spin_unlock_irqrestore(&pool->lock, flags); + + return r; +} + +/* + * Retrieves the number of blocks of the data device from + * the superblock and compares it to the actual device size, + * thus resizing the data device in case it has grown. + * + * This both copes with opening preallocated data devices in the ctr + * being followed by a resume + * -and- + * calling the resume method individually after userspace has + * grown the data device in reaction to a table event. + */ +static int pool_preresume(struct dm_target *ti) +{ + int r; + struct pool_c *pt = ti->private; + struct pool *pool = pt->pool; + dm_block_t data_size, sb_data_size; + + /* + * Take control of the pool object. + */ + r = bind_control_target(pool, ti); + if (r) + return r; + + data_size = ti->len >> pool->block_shift; + r = dm_pool_get_data_dev_size(pool->pmd, &sb_data_size); + if (r) { + DMERR("failed to retrieve data device size"); + return r; + } + + if (data_size < sb_data_size) { + DMERR("pool target too small, is %llu blocks (expected %llu)", + data_size, sb_data_size); + return -EINVAL; + + } else if (data_size > sb_data_size) { + r = dm_pool_resize_data_dev(pool->pmd, data_size); + if (r) { + DMERR("failed to resize data device"); + return r; + } + + r = dm_pool_commit_metadata(pool->pmd); + if (r) { + DMERR("%s: dm_pool_commit_metadata() failed, error = %d", + __func__, r); + return r; + } + } + + return 0; +} + +static void pool_resume(struct dm_target *ti) +{ + struct pool_c *pt = ti->private; + struct pool *pool = pt->pool; + unsigned long flags; + + spin_lock_irqsave(&pool->lock, flags); + pool->low_water_triggered = 0; + pool->no_free_space = 0; + __requeue_bios(pool); + spin_unlock_irqrestore(&pool->lock, flags); + + wake_worker(pool); +} + +static void pool_postsuspend(struct dm_target *ti) +{ + int r; + struct pool_c *pt = ti->private; + struct pool *pool = pt->pool; + + flush_workqueue(pool->wq); + + r = dm_pool_commit_metadata(pool->pmd); + if (r < 0) { + DMERR("%s: dm_pool_commit_metadata() failed, error = %d", + __func__, r); + /* FIXME: invalidate device? error the next FUA or FLUSH bio ?*/ + } +} + +static int check_arg_count(unsigned argc, unsigned args_required) +{ + if (argc != args_required) { + DMWARN("Message received with %u arguments instead of %u.", + argc, args_required); + return -EINVAL; + } + + return 0; +} + +static int read_dev_id(char *arg, dm_thin_id *dev_id, int warning) +{ + if (!kstrtoull(arg, 10, (unsigned long long *)dev_id) && + *dev_id <= MAX_DEV_ID) + return 0; + + if (warning) + DMWARN("Message received with invalid device id: %s", arg); + + return -EINVAL; +} + +static int process_create_thin_mesg(unsigned argc, char **argv, struct pool *pool) +{ + dm_thin_id dev_id; + int r; + + r = check_arg_count(argc, 2); + if (r) + return r; + + r = read_dev_id(argv[1], &dev_id, 1); + if (r) + return r; + + r = dm_pool_create_thin(pool->pmd, dev_id); + if (r) { + DMWARN("Creation of new thinly-provisioned device with id %s failed.", + argv[1]); + return r; + } + + return 0; +} + +static int process_create_snap_mesg(unsigned argc, char **argv, struct pool *pool) +{ + dm_thin_id dev_id; + dm_thin_id origin_dev_id; + int r; + + r = check_arg_count(argc, 3); + if (r) + return r; + + r = read_dev_id(argv[1], &dev_id, 1); + if (r) + return r; + + r = read_dev_id(argv[2], &origin_dev_id, 1); + if (r) + return r; + + r = dm_pool_create_snap(pool->pmd, dev_id, origin_dev_id); + if (r) { + DMWARN("Creation of new snapshot %s of device %s failed.", + argv[1], argv[2]); + return r; + } + + return 0; +} + +static int process_delete_mesg(unsigned argc, char **argv, struct pool *pool) +{ + dm_thin_id dev_id; + int r; + + r = check_arg_count(argc, 2); + if (r) + return r; + + r = read_dev_id(argv[1], &dev_id, 1); + if (r) + return r; + + r = dm_pool_delete_thin_device(pool->pmd, dev_id); + if (r) + DMWARN("Deletion of thin device %s failed.", argv[1]); + + return r; +} + +static int process_set_transaction_id_mesg(unsigned argc, char **argv, struct pool *pool) +{ + dm_thin_id old_id, new_id; + int r; + + r = check_arg_count(argc, 3); + if (r) + return r; + + if (kstrtoull(argv[1], 10, (unsigned long long *)&old_id)) { + DMWARN("set_transaction_id message: Unrecognised id %s.", argv[1]); + return -EINVAL; + } + + if (kstrtoull(argv[2], 10, (unsigned long long *)&new_id)) { + DMWARN("set_transaction_id message: Unrecognised new id %s.", argv[2]); + return -EINVAL; + } + + r = dm_pool_set_metadata_transaction_id(pool->pmd, old_id, new_id); + if (r) { + DMWARN("Failed to change transaction id from %s to %s.", + argv[1], argv[2]); + return r; + } + + return 0; +} + +/* + * Messages supported: + * create_thin <dev_id> + * create_snap <dev_id> <origin_id> + * delete <dev_id> + * trim <dev_id> <new_size_in_sectors> + * set_transaction_id <current_trans_id> <new_trans_id> + */ +static int pool_message(struct dm_target *ti, unsigned argc, char **argv) +{ + int r = -EINVAL; + struct pool_c *pt = ti->private; + struct pool *pool = pt->pool; + + if (!strcasecmp(argv[0], "create_thin")) + r = process_create_thin_mesg(argc, argv, pool); + + else if (!strcasecmp(argv[0], "create_snap")) + r = process_create_snap_mesg(argc, argv, pool); + + else if (!strcasecmp(argv[0], "delete")) + r = process_delete_mesg(argc, argv, pool); + + else if (!strcasecmp(argv[0], "set_transaction_id")) + r = process_set_transaction_id_mesg(argc, argv, pool); + + else + DMWARN("Unrecognised thin pool target message received: %s", argv[0]); + + if (!r) { + r = dm_pool_commit_metadata(pool->pmd); + if (r) + DMERR("%s message: dm_pool_commit_metadata() failed, error = %d", + argv[0], r); + } + + return r; +} + +/* + * Status line is: + * <transaction id> <used metadata sectors>/<total metadata sectors> + * <used data sectors>/<total data sectors> <held metadata root> + */ +static int pool_status(struct dm_target *ti, status_type_t type, + char *result, unsigned maxlen) +{ + int r; + unsigned sz = 0; + uint64_t transaction_id; + dm_block_t nr_free_blocks_data; + dm_block_t nr_free_blocks_metadata; + dm_block_t nr_blocks_data; + dm_block_t nr_blocks_metadata; + dm_block_t held_root; + char buf[BDEVNAME_SIZE]; + char buf2[BDEVNAME_SIZE]; + struct pool_c *pt = ti->private; + struct pool *pool = pt->pool; + + switch (type) { + case STATUSTYPE_INFO: + r = dm_pool_get_metadata_transaction_id(pool->pmd, + &transaction_id); + if (r) + return r; + + r = dm_pool_get_free_metadata_block_count(pool->pmd, + &nr_free_blocks_metadata); + if (r) + return r; + + r = dm_pool_get_metadata_dev_size(pool->pmd, &nr_blocks_metadata); + if (r) + return r; + + r = dm_pool_get_free_block_count(pool->pmd, + &nr_free_blocks_data); + if (r) + return r; + + r = dm_pool_get_data_dev_size(pool->pmd, &nr_blocks_data); + if (r) + return r; + + r = dm_pool_get_held_metadata_root(pool->pmd, &held_root); + if (r) + return r; + + DMEMIT("%llu %llu/%llu %llu/%llu ", + (unsigned long long)transaction_id, + (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata), + (unsigned long long)nr_blocks_metadata, + (unsigned long long)(nr_blocks_data - nr_free_blocks_data), + (unsigned long long)nr_blocks_data); + + if (held_root) + DMEMIT("%llu", held_root); + else + DMEMIT("-"); + + break; + + case STATUSTYPE_TABLE: + DMEMIT("%s %s %lu %llu ", + format_dev_t(buf, pt->metadata_dev->bdev->bd_dev), + format_dev_t(buf2, pt->data_dev->bdev->bd_dev), + (unsigned long)pool->sectors_per_block, + (unsigned long long)pt->low_water_blocks); + + DMEMIT("%u ", !pool->zero_new_blocks); + + if (!pool->zero_new_blocks) + DMEMIT("skip_block_zeroing "); + break; + } + + return 0; +} + +static int pool_iterate_devices(struct dm_target *ti, + iterate_devices_callout_fn fn, void *data) +{ + struct pool_c *pt = ti->private; + + return fn(ti, pt->data_dev, 0, ti->len, data); +} + +static int pool_merge(struct dm_target *ti, struct bvec_merge_data *bvm, + struct bio_vec *biovec, int max_size) +{ + struct pool_c *pt = ti->private; + struct request_queue *q = bdev_get_queue(pt->data_dev->bdev); + + if (!q->merge_bvec_fn) + return max_size; + + bvm->bi_bdev = pt->data_dev->bdev; + + return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); +} + +static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits) +{ + struct pool_c *pt = ti->private; + struct pool *pool = pt->pool; + + blk_limits_io_min(limits, 0); + blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT); +} + +static struct target_type pool_target = { + .name = "thin-pool", + .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE | + DM_TARGET_IMMUTABLE, + .version = {1, 0, 0}, + .module = THIS_MODULE, + .ctr = pool_ctr, + .dtr = pool_dtr, + .map = pool_map, + .postsuspend = pool_postsuspend, + .preresume = pool_preresume, + .resume = pool_resume, + .message = pool_message, + .status = pool_status, + .merge = pool_merge, + .iterate_devices = pool_iterate_devices, + .io_hints = pool_io_hints, +}; + +/*---------------------------------------------------------------- + * Thin target methods + *--------------------------------------------------------------*/ +static void thin_dtr(struct dm_target *ti) +{ + struct thin_c *tc = ti->private; + + mutex_lock(&dm_thin_pool_table.mutex); + + __pool_dec(tc->pool); + dm_pool_close_thin_device(tc->td); + dm_put_device(ti, tc->pool_dev); + kfree(tc); + + mutex_unlock(&dm_thin_pool_table.mutex); +} + +/* + * Thin target parameters: + * + * <pool_dev> <dev_id> + * + * pool_dev: the path to the pool (eg, /dev/mapper/my_pool) + * dev_id: the internal device identifier + */ +static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv) +{ + int r; + struct thin_c *tc; + struct dm_dev *pool_dev; + struct mapped_device *pool_md; + + mutex_lock(&dm_thin_pool_table.mutex); + + if (argc != 2) { + ti->error = "Invalid argument count"; + r = -EINVAL; + goto out_unlock; + } + + tc = ti->private = kzalloc(sizeof(*tc), GFP_KERNEL); + if (!tc) { + ti->error = "Out of memory"; + r = -ENOMEM; + goto out_unlock; + } + + r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &pool_dev); + if (r) { + ti->error = "Error opening pool device"; + goto bad_pool_dev; + } + tc->pool_dev = pool_dev; + + if (read_dev_id(argv[1], (unsigned long long *)&tc->dev_id, 0)) { + ti->error = "Invalid device id"; + r = -EINVAL; + goto bad_common; + } + + pool_md = dm_get_md(tc->pool_dev->bdev->bd_dev); + if (!pool_md) { + ti->error = "Couldn't get pool mapped device"; + r = -EINVAL; + goto bad_common; + } + + tc->pool = __pool_table_lookup(pool_md); + if (!tc->pool) { + ti->error = "Couldn't find pool object"; + r = -EINVAL; + goto bad_pool_lookup; + } + __pool_inc(tc->pool); + + r = dm_pool_open_thin_device(tc->pool->pmd, tc->dev_id, &tc->td); + if (r) { + ti->error = "Couldn't open thin internal device"; + goto bad_thin_open; + } + + ti->split_io = tc->pool->sectors_per_block; + ti->num_flush_requests = 1; + ti->num_discard_requests = 0; + ti->discards_supported = 0; + + dm_put(pool_md); + + mutex_unlock(&dm_thin_pool_table.mutex); + + return 0; + +bad_thin_open: + __pool_dec(tc->pool); +bad_pool_lookup: + dm_put(pool_md); +bad_common: + dm_put_device(ti, tc->pool_dev); +bad_pool_dev: + kfree(tc); +out_unlock: + mutex_unlock(&dm_thin_pool_table.mutex); + + return r; +} + +static int thin_map(struct dm_target *ti, struct bio *bio, + union map_info *map_context) +{ + bio->bi_sector -= ti->begin; + + return thin_bio_map(ti, bio, map_context); +} + +static void thin_postsuspend(struct dm_target *ti) +{ + if (dm_noflush_suspending(ti)) + requeue_io((struct thin_c *)ti->private); +} + +/* + * <nr mapped sectors> <highest mapped sector> + */ +static int thin_status(struct dm_target *ti, status_type_t type, + char *result, unsigned maxlen) +{ + int r; + ssize_t sz = 0; + dm_block_t mapped, highest; + char buf[BDEVNAME_SIZE]; + struct thin_c *tc = ti->private; + + if (!tc->td) + DMEMIT("-"); + else { + switch (type) { + case STATUSTYPE_INFO: + r = dm_thin_get_mapped_count(tc->td, &mapped); + if (r) + return r; + + r = dm_thin_get_highest_mapped_block(tc->td, &highest); + if (r < 0) + return r; + + DMEMIT("%llu ", mapped * tc->pool->sectors_per_block); + if (r) + DMEMIT("%llu", ((highest + 1) * + tc->pool->sectors_per_block) - 1); + else + DMEMIT("-"); + break; + + case STATUSTYPE_TABLE: + DMEMIT("%s %lu", + format_dev_t(buf, tc->pool_dev->bdev->bd_dev), + (unsigned long) tc->dev_id); + break; + } + } + + return 0; +} + +static int thin_iterate_devices(struct dm_target *ti, + iterate_devices_callout_fn fn, void *data) +{ + dm_block_t blocks; + struct thin_c *tc = ti->private; + + /* + * We can't call dm_pool_get_data_dev_size() since that blocks. So + * we follow a more convoluted path through to the pool's target. + */ + if (!tc->pool->ti) + return 0; /* nothing is bound */ + + blocks = tc->pool->ti->len >> tc->pool->block_shift; + if (blocks) + return fn(ti, tc->pool_dev, 0, tc->pool->sectors_per_block * blocks, data); + + return 0; +} + +static void thin_io_hints(struct dm_target *ti, struct queue_limits *limits) +{ + struct thin_c *tc = ti->private; + + blk_limits_io_min(limits, 0); + blk_limits_io_opt(limits, tc->pool->sectors_per_block << SECTOR_SHIFT); +} + +static struct target_type thin_target = { + .name = "thin", + .version = {1, 0, 0}, + .module = THIS_MODULE, + .ctr = thin_ctr, + .dtr = thin_dtr, + .map = thin_map, + .postsuspend = thin_postsuspend, + .status = thin_status, + .iterate_devices = thin_iterate_devices, + .io_hints = thin_io_hints, +}; + +/*----------------------------------------------------------------*/ + +static int __init dm_thin_init(void) +{ + int r; + + pool_table_init(); + + r = dm_register_target(&thin_target); + if (r) + return r; + + r = dm_register_target(&pool_target); + if (r) + dm_unregister_target(&thin_target); + + return r; +} + +static void dm_thin_exit(void) +{ + dm_unregister_target(&thin_target); + dm_unregister_target(&pool_target); +} + +module_init(dm_thin_init); +module_exit(dm_thin_exit); + +MODULE_DESCRIPTION(DM_NAME "device-mapper thin provisioning target"); +MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>"); +MODULE_LICENSE("GPL"); diff --git a/drivers/md/dm-uevent.c b/drivers/md/dm-uevent.c index 6b1e3b61b25..8efe033bab5 100644 --- a/drivers/md/dm-uevent.c +++ b/drivers/md/dm-uevent.c @@ -22,6 +22,7 @@ #include <linux/slab.h> #include <linux/kobject.h> #include <linux/dm-ioctl.h> +#include <linux/export.h> #include "dm.h" #include "dm-uevent.h" diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 52b39f335bb..4720f68f817 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -25,6 +25,16 @@ #define DM_MSG_PREFIX "core" +#ifdef CONFIG_PRINTK +/* + * ratelimit state to be used in DMXXX_LIMIT(). + */ +DEFINE_RATELIMIT_STATE(dm_ratelimit_state, + DEFAULT_RATELIMIT_INTERVAL, + DEFAULT_RATELIMIT_BURST); +EXPORT_SYMBOL(dm_ratelimit_state); +#endif + /* * Cookies are numeric values sent with CHANGE and REMOVE * uevents while resuming, removing or renaming the device. @@ -130,6 +140,8 @@ struct mapped_device { /* Protect queue and type against concurrent access. */ struct mutex type_lock; + struct target_type *immutable_target_type; + struct gendisk *disk; char name[16]; @@ -180,9 +192,6 @@ struct mapped_device { /* forced geometry settings */ struct hd_geometry geometry; - /* For saving the address of __make_request for request based dm */ - make_request_fn *saved_make_request_fn; - /* sysfs handle */ struct kobject kobj; @@ -1391,7 +1400,7 @@ out: * The request function that just remaps the bio built up by * dm_merge_bvec. */ -static int _dm_request(struct request_queue *q, struct bio *bio) +static void _dm_request(struct request_queue *q, struct bio *bio) { int rw = bio_data_dir(bio); struct mapped_device *md = q->queuedata; @@ -1412,19 +1421,12 @@ static int _dm_request(struct request_queue *q, struct bio *bio) queue_io(md, bio); else bio_io_error(bio); - return 0; + return; } __split_and_process_bio(md, bio); up_read(&md->io_lock); - return 0; -} - -static int dm_make_request(struct request_queue *q, struct bio *bio) -{ - struct mapped_device *md = q->queuedata; - - return md->saved_make_request_fn(q, bio); /* call __make_request() */ + return; } static int dm_request_based(struct mapped_device *md) @@ -1432,14 +1434,14 @@ static int dm_request_based(struct mapped_device *md) return blk_queue_stackable(md->queue); } -static int dm_request(struct request_queue *q, struct bio *bio) +static void dm_request(struct request_queue *q, struct bio *bio) { struct mapped_device *md = q->queuedata; if (dm_request_based(md)) - return dm_make_request(q, bio); - - return _dm_request(q, bio); + blk_queue_bio(q, bio); + else + _dm_request(q, bio); } void dm_dispatch_request(struct request *rq) @@ -2086,6 +2088,8 @@ static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t, write_lock_irqsave(&md->map_lock, flags); old_map = md->map; md->map = t; + md->immutable_target_type = dm_table_get_immutable_target_type(t); + dm_table_set_restrictions(t, q, limits); if (merge_is_optional) set_bit(DMF_MERGE_IS_OPTIONAL, &md->flags); @@ -2156,6 +2160,11 @@ unsigned dm_get_md_type(struct mapped_device *md) return md->type; } +struct target_type *dm_get_immutable_target_type(struct mapped_device *md) +{ + return md->immutable_target_type; +} + /* * Fully initialize a request-based queue (->elevator, ->request_fn, etc). */ @@ -2172,7 +2181,6 @@ static int dm_init_request_based_queue(struct mapped_device *md) return 0; md->queue = q; - md->saved_make_request_fn = md->queue->make_request_fn; dm_init_md_queue(md); blk_queue_softirq_done(md->queue, dm_softirq_done); blk_queue_prep_rq(md->queue, dm_prep_fn); @@ -2231,6 +2239,7 @@ struct mapped_device *dm_get_md(dev_t dev) return md; } +EXPORT_SYMBOL_GPL(dm_get_md); void *dm_get_mdptr(struct mapped_device *md) { @@ -2316,7 +2325,6 @@ static int dm_wait_for_completion(struct mapped_device *md, int interruptible) while (1) { set_current_state(interruptible); - smp_mb(); if (!md_in_flight(md)) break; diff --git a/drivers/md/dm.h b/drivers/md/dm.h index 6745dbd278a..b7dacd59d8d 100644 --- a/drivers/md/dm.h +++ b/drivers/md/dm.h @@ -60,6 +60,7 @@ int dm_table_resume_targets(struct dm_table *t); int dm_table_any_congested(struct dm_table *t, int bdi_bits); int dm_table_any_busy_target(struct dm_table *t); unsigned dm_table_get_type(struct dm_table *t); +struct target_type *dm_table_get_immutable_target_type(struct dm_table *t); bool dm_table_request_based(struct dm_table *t); bool dm_table_supports_discards(struct dm_table *t); int dm_table_alloc_md_mempools(struct dm_table *t); @@ -72,6 +73,7 @@ void dm_lock_md_type(struct mapped_device *md); void dm_unlock_md_type(struct mapped_device *md); void dm_set_md_type(struct mapped_device *md, unsigned type); unsigned dm_get_md_type(struct mapped_device *md); +struct target_type *dm_get_immutable_target_type(struct mapped_device *md); int dm_setup_md_queue(struct mapped_device *md); diff --git a/drivers/md/faulty.c b/drivers/md/faulty.c index 60816b132c2..feb2c3c7bb4 100644 --- a/drivers/md/faulty.c +++ b/drivers/md/faulty.c @@ -63,6 +63,7 @@ #define MaxFault 50 #include <linux/blkdev.h> +#include <linux/module.h> #include <linux/raid/md_u.h> #include <linux/slab.h> #include "md.h" @@ -169,7 +170,7 @@ static void add_sector(struct faulty_conf *conf, sector_t start, int mode) conf->nfaults = n+1; } -static int make_request(struct mddev *mddev, struct bio *bio) +static void make_request(struct mddev *mddev, struct bio *bio) { struct faulty_conf *conf = mddev->private; int failit = 0; @@ -181,7 +182,7 @@ static int make_request(struct mddev *mddev, struct bio *bio) * just fail immediately */ bio_endio(bio, -EIO); - return 0; + return; } if (check_sector(conf, bio->bi_sector, bio->bi_sector+(bio->bi_size>>9), @@ -211,15 +212,15 @@ static int make_request(struct mddev *mddev, struct bio *bio) } if (failit) { struct bio *b = bio_clone_mddev(bio, GFP_NOIO, mddev); + b->bi_bdev = conf->rdev->bdev; b->bi_private = bio; b->bi_end_io = faulty_fail; - generic_make_request(b); - return 0; - } else { + bio = b; + } else bio->bi_bdev = conf->rdev->bdev; - return 1; - } + + generic_make_request(bio); } static void status(struct seq_file *seq, struct mddev *mddev) diff --git a/drivers/md/linear.c b/drivers/md/linear.c index 10c5844460c..c3273efd08c 100644 --- a/drivers/md/linear.c +++ b/drivers/md/linear.c @@ -19,6 +19,7 @@ #include <linux/blkdev.h> #include <linux/raid/md_u.h> #include <linux/seq_file.h> +#include <linux/module.h> #include <linux/slab.h> #include "md.h" #include "linear.h" @@ -264,14 +265,14 @@ static int linear_stop (struct mddev *mddev) return 0; } -static int linear_make_request (struct mddev *mddev, struct bio *bio) +static void linear_make_request(struct mddev *mddev, struct bio *bio) { struct dev_info *tmp_dev; sector_t start_sector; if (unlikely(bio->bi_rw & REQ_FLUSH)) { md_flush_request(mddev, bio); - return 0; + return; } rcu_read_lock(); @@ -293,7 +294,7 @@ static int linear_make_request (struct mddev *mddev, struct bio *bio) (unsigned long long)start_sector); rcu_read_unlock(); bio_io_error(bio); - return 0; + return; } if (unlikely(bio->bi_sector + (bio->bi_size >> 9) > tmp_dev->end_sector)) { @@ -307,20 +308,17 @@ static int linear_make_request (struct mddev *mddev, struct bio *bio) bp = bio_split(bio, end_sector - bio->bi_sector); - if (linear_make_request(mddev, &bp->bio1)) - generic_make_request(&bp->bio1); - if (linear_make_request(mddev, &bp->bio2)) - generic_make_request(&bp->bio2); + linear_make_request(mddev, &bp->bio1); + linear_make_request(mddev, &bp->bio2); bio_pair_release(bp); - return 0; + return; } bio->bi_bdev = tmp_dev->rdev->bdev; bio->bi_sector = bio->bi_sector - start_sector + tmp_dev->rdev->data_offset; rcu_read_unlock(); - - return 1; + generic_make_request(bio); } static void linear_status (struct seq_file *seq, struct mddev *mddev) diff --git a/drivers/md/md.c b/drivers/md/md.c index 266e82ebaf1..84acfe7d10e 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -44,6 +44,7 @@ #include <linux/hdreg.h> #include <linux/proc_fs.h> #include <linux/random.h> +#include <linux/module.h> #include <linux/reboot.h> #include <linux/file.h> #include <linux/compat.h> @@ -332,18 +333,17 @@ static DEFINE_SPINLOCK(all_mddevs_lock); * call has finished, the bio has been linked into some internal structure * and so is visible to ->quiesce(), so we don't need the refcount any more. */ -static int md_make_request(struct request_queue *q, struct bio *bio) +static void md_make_request(struct request_queue *q, struct bio *bio) { const int rw = bio_data_dir(bio); struct mddev *mddev = q->queuedata; - int rv; int cpu; unsigned int sectors; if (mddev == NULL || mddev->pers == NULL || !mddev->ready) { bio_io_error(bio); - return 0; + return; } smp_rmb(); /* Ensure implications of 'active' are visible */ rcu_read_lock(); @@ -368,7 +368,7 @@ static int md_make_request(struct request_queue *q, struct bio *bio) * go away inside make_request */ sectors = bio_sectors(bio); - rv = mddev->pers->make_request(mddev, bio); + mddev->pers->make_request(mddev, bio); cpu = part_stat_lock(); part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]); @@ -377,8 +377,6 @@ static int md_make_request(struct request_queue *q, struct bio *bio) if (atomic_dec_and_test(&mddev->active_io) && mddev->suspended) wake_up(&mddev->sb_wait); - - return rv; } /* mddev_suspend makes sure no new requests are submitted @@ -477,8 +475,7 @@ static void md_submit_flush_data(struct work_struct *ws) bio_endio(bio, 0); else { bio->bi_rw &= ~REQ_FLUSH; - if (mddev->pers->make_request(mddev, bio)) - generic_make_request(bio); + mddev->pers->make_request(mddev, bio); } mddev->flush_bio = NULL; diff --git a/drivers/md/md.h b/drivers/md/md.h index 51c1d91557e..cf742d9306e 100644 --- a/drivers/md/md.h +++ b/drivers/md/md.h @@ -419,7 +419,7 @@ struct md_personality int level; struct list_head list; struct module *owner; - int (*make_request)(struct mddev *mddev, struct bio *bio); + void (*make_request)(struct mddev *mddev, struct bio *bio); int (*run)(struct mddev *mddev); int (*stop)(struct mddev *mddev); void (*status)(struct seq_file *seq, struct mddev *mddev); diff --git a/drivers/md/multipath.c b/drivers/md/multipath.c index d32c785e17d..5899246fa37 100644 --- a/drivers/md/multipath.c +++ b/drivers/md/multipath.c @@ -20,6 +20,7 @@ */ #include <linux/blkdev.h> +#include <linux/module.h> #include <linux/raid/md_u.h> #include <linux/seq_file.h> #include <linux/slab.h> @@ -106,7 +107,7 @@ static void multipath_end_request(struct bio *bio, int error) rdev_dec_pending(rdev, conf->mddev); } -static int multipath_make_request(struct mddev *mddev, struct bio * bio) +static void multipath_make_request(struct mddev *mddev, struct bio * bio) { struct mpconf *conf = mddev->private; struct multipath_bh * mp_bh; @@ -114,7 +115,7 @@ static int multipath_make_request(struct mddev *mddev, struct bio * bio) if (unlikely(bio->bi_rw & REQ_FLUSH)) { md_flush_request(mddev, bio); - return 0; + return; } mp_bh = mempool_alloc(conf->pool, GFP_NOIO); @@ -126,7 +127,7 @@ static int multipath_make_request(struct mddev *mddev, struct bio * bio) if (mp_bh->path < 0) { bio_endio(bio, -EIO); mempool_free(mp_bh, conf->pool); - return 0; + return; } multipath = conf->multipaths + mp_bh->path; @@ -137,7 +138,7 @@ static int multipath_make_request(struct mddev *mddev, struct bio * bio) mp_bh->bio.bi_end_io = multipath_end_request; mp_bh->bio.bi_private = mp_bh; generic_make_request(&mp_bh->bio); - return 0; + return; } static void multipath_status (struct seq_file *seq, struct mddev *mddev) diff --git a/drivers/md/persistent-data/Kconfig b/drivers/md/persistent-data/Kconfig new file mode 100644 index 00000000000..ceb359050a5 --- /dev/null +++ b/drivers/md/persistent-data/Kconfig @@ -0,0 +1,8 @@ +config DM_PERSISTENT_DATA + tristate + depends on BLK_DEV_DM && EXPERIMENTAL + select LIBCRC32C + select DM_BUFIO + ---help--- + Library providing immutable on-disk data structure support for + device-mapper targets such as the thin provisioning target. diff --git a/drivers/md/persistent-data/Makefile b/drivers/md/persistent-data/Makefile new file mode 100644 index 00000000000..cfa95f66223 --- /dev/null +++ b/drivers/md/persistent-data/Makefile @@ -0,0 +1,11 @@ +obj-$(CONFIG_DM_PERSISTENT_DATA) += dm-persistent-data.o +dm-persistent-data-objs := \ + dm-block-manager.o \ + dm-space-map-checker.o \ + dm-space-map-common.o \ + dm-space-map-disk.o \ + dm-space-map-metadata.o \ + dm-transaction-manager.o \ + dm-btree.o \ + dm-btree-remove.o \ + dm-btree-spine.o diff --git a/drivers/md/persistent-data/dm-block-manager.c b/drivers/md/persistent-data/dm-block-manager.c new file mode 100644 index 00000000000..0317ecdc6e5 --- /dev/null +++ b/drivers/md/persistent-data/dm-block-manager.c @@ -0,0 +1,620 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ +#include "dm-block-manager.h" +#include "dm-persistent-data-internal.h" +#include "../dm-bufio.h" + +#include <linux/crc32c.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/rwsem.h> +#include <linux/device-mapper.h> +#include <linux/stacktrace.h> + +#define DM_MSG_PREFIX "block manager" + +/*----------------------------------------------------------------*/ + +/* + * This is a read/write semaphore with a couple of differences. + * + * i) There is a restriction on the number of concurrent read locks that + * may be held at once. This is just an implementation detail. + * + * ii) Recursive locking attempts are detected and return EINVAL. A stack + * trace is also emitted for the previous lock aquisition. + * + * iii) Priority is given to write locks. + */ +#define MAX_HOLDERS 4 +#define MAX_STACK 10 + +typedef unsigned long stack_entries[MAX_STACK]; + +struct block_lock { + spinlock_t lock; + __s32 count; + struct list_head waiters; + struct task_struct *holders[MAX_HOLDERS]; + +#ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING + struct stack_trace traces[MAX_HOLDERS]; + stack_entries entries[MAX_HOLDERS]; +#endif +}; + +struct waiter { + struct list_head list; + struct task_struct *task; + int wants_write; +}; + +static unsigned __find_holder(struct block_lock *lock, + struct task_struct *task) +{ + unsigned i; + + for (i = 0; i < MAX_HOLDERS; i++) + if (lock->holders[i] == task) + break; + + BUG_ON(i == MAX_HOLDERS); + return i; +} + +/* call this *after* you increment lock->count */ +static void __add_holder(struct block_lock *lock, struct task_struct *task) +{ + unsigned h = __find_holder(lock, NULL); +#ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING + struct stack_trace *t; +#endif + + get_task_struct(task); + lock->holders[h] = task; + +#ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING + t = lock->traces + h; + t->nr_entries = 0; + t->max_entries = MAX_STACK; + t->entries = lock->entries[h]; + t->skip = 2; + save_stack_trace(t); +#endif +} + +/* call this *before* you decrement lock->count */ +static void __del_holder(struct block_lock *lock, struct task_struct *task) +{ + unsigned h = __find_holder(lock, task); + lock->holders[h] = NULL; + put_task_struct(task); +} + +static int __check_holder(struct block_lock *lock) +{ + unsigned i; +#ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING + static struct stack_trace t; + static stack_entries entries; +#endif + + for (i = 0; i < MAX_HOLDERS; i++) { + if (lock->holders[i] == current) { + DMERR("recursive lock detected in pool metadata"); +#ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING + DMERR("previously held here:"); + print_stack_trace(lock->traces + i, 4); + + DMERR("subsequent aquisition attempted here:"); + t.nr_entries = 0; + t.max_entries = MAX_STACK; + t.entries = entries; + t.skip = 3; + save_stack_trace(&t); + print_stack_trace(&t, 4); +#endif + return -EINVAL; + } + } + + return 0; +} + +static void __wait(struct waiter *w) +{ + for (;;) { + set_task_state(current, TASK_UNINTERRUPTIBLE); + + if (!w->task) + break; + + schedule(); + } + + set_task_state(current, TASK_RUNNING); +} + +static void __wake_waiter(struct waiter *w) +{ + struct task_struct *task; + + list_del(&w->list); + task = w->task; + smp_mb(); + w->task = NULL; + wake_up_process(task); +} + +/* + * We either wake a few readers or a single writer. + */ +static void __wake_many(struct block_lock *lock) +{ + struct waiter *w, *tmp; + + BUG_ON(lock->count < 0); + list_for_each_entry_safe(w, tmp, &lock->waiters, list) { + if (lock->count >= MAX_HOLDERS) + return; + + if (w->wants_write) { + if (lock->count > 0) + return; /* still read locked */ + + lock->count = -1; + __add_holder(lock, w->task); + __wake_waiter(w); + return; + } + + lock->count++; + __add_holder(lock, w->task); + __wake_waiter(w); + } +} + +static void bl_init(struct block_lock *lock) +{ + int i; + + spin_lock_init(&lock->lock); + lock->count = 0; + INIT_LIST_HEAD(&lock->waiters); + for (i = 0; i < MAX_HOLDERS; i++) + lock->holders[i] = NULL; +} + +static int __available_for_read(struct block_lock *lock) +{ + return lock->count >= 0 && + lock->count < MAX_HOLDERS && + list_empty(&lock->waiters); +} + +static int bl_down_read(struct block_lock *lock) +{ + int r; + struct waiter w; + + spin_lock(&lock->lock); + r = __check_holder(lock); + if (r) { + spin_unlock(&lock->lock); + return r; + } + + if (__available_for_read(lock)) { + lock->count++; + __add_holder(lock, current); + spin_unlock(&lock->lock); + return 0; + } + + get_task_struct(current); + + w.task = current; + w.wants_write = 0; + list_add_tail(&w.list, &lock->waiters); + spin_unlock(&lock->lock); + + __wait(&w); + put_task_struct(current); + return 0; +} + +static int bl_down_read_nonblock(struct block_lock *lock) +{ + int r; + + spin_lock(&lock->lock); + r = __check_holder(lock); + if (r) + goto out; + + if (__available_for_read(lock)) { + lock->count++; + __add_holder(lock, current); + r = 0; + } else + r = -EWOULDBLOCK; + +out: + spin_unlock(&lock->lock); + return r; +} + +static void bl_up_read(struct block_lock *lock) +{ + spin_lock(&lock->lock); + BUG_ON(lock->count <= 0); + __del_holder(lock, current); + --lock->count; + if (!list_empty(&lock->waiters)) + __wake_many(lock); + spin_unlock(&lock->lock); +} + +static int bl_down_write(struct block_lock *lock) +{ + int r; + struct waiter w; + + spin_lock(&lock->lock); + r = __check_holder(lock); + if (r) { + spin_unlock(&lock->lock); + return r; + } + + if (lock->count == 0 && list_empty(&lock->waiters)) { + lock->count = -1; + __add_holder(lock, current); + spin_unlock(&lock->lock); + return 0; + } + + get_task_struct(current); + w.task = current; + w.wants_write = 1; + + /* + * Writers given priority. We know there's only one mutator in the + * system, so ignoring the ordering reversal. + */ + list_add(&w.list, &lock->waiters); + spin_unlock(&lock->lock); + + __wait(&w); + put_task_struct(current); + + return 0; +} + +static void bl_up_write(struct block_lock *lock) +{ + spin_lock(&lock->lock); + __del_holder(lock, current); + lock->count = 0; + if (!list_empty(&lock->waiters)) + __wake_many(lock); + spin_unlock(&lock->lock); +} + +static void report_recursive_bug(dm_block_t b, int r) +{ + if (r == -EINVAL) + DMERR("recursive acquisition of block %llu requested.", + (unsigned long long) b); +} + +/*----------------------------------------------------------------*/ + +/* + * Block manager is currently implemented using dm-bufio. struct + * dm_block_manager and struct dm_block map directly onto a couple of + * structs in the bufio interface. I want to retain the freedom to move + * away from bufio in the future. So these structs are just cast within + * this .c file, rather than making it through to the public interface. + */ +static struct dm_buffer *to_buffer(struct dm_block *b) +{ + return (struct dm_buffer *) b; +} + +static struct dm_bufio_client *to_bufio(struct dm_block_manager *bm) +{ + return (struct dm_bufio_client *) bm; +} + +dm_block_t dm_block_location(struct dm_block *b) +{ + return dm_bufio_get_block_number(to_buffer(b)); +} +EXPORT_SYMBOL_GPL(dm_block_location); + +void *dm_block_data(struct dm_block *b) +{ + return dm_bufio_get_block_data(to_buffer(b)); +} +EXPORT_SYMBOL_GPL(dm_block_data); + +struct buffer_aux { + struct dm_block_validator *validator; + struct block_lock lock; + int write_locked; +}; + +static void dm_block_manager_alloc_callback(struct dm_buffer *buf) +{ + struct buffer_aux *aux = dm_bufio_get_aux_data(buf); + aux->validator = NULL; + bl_init(&aux->lock); +} + +static void dm_block_manager_write_callback(struct dm_buffer *buf) +{ + struct buffer_aux *aux = dm_bufio_get_aux_data(buf); + if (aux->validator) { + aux->validator->prepare_for_write(aux->validator, (struct dm_block *) buf, + dm_bufio_get_block_size(dm_bufio_get_client(buf))); + } +} + +/*---------------------------------------------------------------- + * Public interface + *--------------------------------------------------------------*/ +struct dm_block_manager *dm_block_manager_create(struct block_device *bdev, + unsigned block_size, + unsigned cache_size, + unsigned max_held_per_thread) +{ + return (struct dm_block_manager *) + dm_bufio_client_create(bdev, block_size, max_held_per_thread, + sizeof(struct buffer_aux), + dm_block_manager_alloc_callback, + dm_block_manager_write_callback); +} +EXPORT_SYMBOL_GPL(dm_block_manager_create); + +void dm_block_manager_destroy(struct dm_block_manager *bm) +{ + return dm_bufio_client_destroy(to_bufio(bm)); +} +EXPORT_SYMBOL_GPL(dm_block_manager_destroy); + +unsigned dm_bm_block_size(struct dm_block_manager *bm) +{ + return dm_bufio_get_block_size(to_bufio(bm)); +} +EXPORT_SYMBOL_GPL(dm_bm_block_size); + +dm_block_t dm_bm_nr_blocks(struct dm_block_manager *bm) +{ + return dm_bufio_get_device_size(to_bufio(bm)); +} + +static int dm_bm_validate_buffer(struct dm_block_manager *bm, + struct dm_buffer *buf, + struct buffer_aux *aux, + struct dm_block_validator *v) +{ + if (unlikely(!aux->validator)) { + int r; + if (!v) + return 0; + r = v->check(v, (struct dm_block *) buf, dm_bufio_get_block_size(to_bufio(bm))); + if (unlikely(r)) + return r; + aux->validator = v; + } else { + if (unlikely(aux->validator != v)) { + DMERR("validator mismatch (old=%s vs new=%s) for block %llu", + aux->validator->name, v ? v->name : "NULL", + (unsigned long long) + dm_bufio_get_block_number(buf)); + return -EINVAL; + } + } + + return 0; +} +int dm_bm_read_lock(struct dm_block_manager *bm, dm_block_t b, + struct dm_block_validator *v, + struct dm_block **result) +{ + struct buffer_aux *aux; + void *p; + int r; + + p = dm_bufio_read(to_bufio(bm), b, (struct dm_buffer **) result); + if (unlikely(IS_ERR(p))) + return PTR_ERR(p); + + aux = dm_bufio_get_aux_data(to_buffer(*result)); + r = bl_down_read(&aux->lock); + if (unlikely(r)) { + dm_bufio_release(to_buffer(*result)); + report_recursive_bug(b, r); + return r; + } + + aux->write_locked = 0; + + r = dm_bm_validate_buffer(bm, to_buffer(*result), aux, v); + if (unlikely(r)) { + bl_up_read(&aux->lock); + dm_bufio_release(to_buffer(*result)); + return r; + } + + return 0; +} +EXPORT_SYMBOL_GPL(dm_bm_read_lock); + +int dm_bm_write_lock(struct dm_block_manager *bm, + dm_block_t b, struct dm_block_validator *v, + struct dm_block **result) +{ + struct buffer_aux *aux; + void *p; + int r; + + p = dm_bufio_read(to_bufio(bm), b, (struct dm_buffer **) result); + if (unlikely(IS_ERR(p))) + return PTR_ERR(p); + + aux = dm_bufio_get_aux_data(to_buffer(*result)); + r = bl_down_write(&aux->lock); + if (r) { + dm_bufio_release(to_buffer(*result)); + report_recursive_bug(b, r); + return r; + } + + aux->write_locked = 1; + + r = dm_bm_validate_buffer(bm, to_buffer(*result), aux, v); + if (unlikely(r)) { + bl_up_write(&aux->lock); + dm_bufio_release(to_buffer(*result)); + return r; + } + + return 0; +} +EXPORT_SYMBOL_GPL(dm_bm_write_lock); + +int dm_bm_read_try_lock(struct dm_block_manager *bm, + dm_block_t b, struct dm_block_validator *v, + struct dm_block **result) +{ + struct buffer_aux *aux; + void *p; + int r; + + p = dm_bufio_get(to_bufio(bm), b, (struct dm_buffer **) result); + if (unlikely(IS_ERR(p))) + return PTR_ERR(p); + if (unlikely(!p)) + return -EWOULDBLOCK; + + aux = dm_bufio_get_aux_data(to_buffer(*result)); + r = bl_down_read_nonblock(&aux->lock); + if (r < 0) { + dm_bufio_release(to_buffer(*result)); + report_recursive_bug(b, r); + return r; + } + aux->write_locked = 0; + + r = dm_bm_validate_buffer(bm, to_buffer(*result), aux, v); + if (unlikely(r)) { + bl_up_read(&aux->lock); + dm_bufio_release(to_buffer(*result)); + return r; + } + + return 0; +} + +int dm_bm_write_lock_zero(struct dm_block_manager *bm, + dm_block_t b, struct dm_block_validator *v, + struct dm_block **result) +{ + int r; + struct buffer_aux *aux; + void *p; + + p = dm_bufio_new(to_bufio(bm), b, (struct dm_buffer **) result); + if (unlikely(IS_ERR(p))) + return PTR_ERR(p); + + memset(p, 0, dm_bm_block_size(bm)); + + aux = dm_bufio_get_aux_data(to_buffer(*result)); + r = bl_down_write(&aux->lock); + if (r) { + dm_bufio_release(to_buffer(*result)); + return r; + } + + aux->write_locked = 1; + aux->validator = v; + + return 0; +} + +int dm_bm_unlock(struct dm_block *b) +{ + struct buffer_aux *aux; + aux = dm_bufio_get_aux_data(to_buffer(b)); + + if (aux->write_locked) { + dm_bufio_mark_buffer_dirty(to_buffer(b)); + bl_up_write(&aux->lock); + } else + bl_up_read(&aux->lock); + + dm_bufio_release(to_buffer(b)); + + return 0; +} +EXPORT_SYMBOL_GPL(dm_bm_unlock); + +int dm_bm_unlock_move(struct dm_block *b, dm_block_t n) +{ + struct buffer_aux *aux; + + aux = dm_bufio_get_aux_data(to_buffer(b)); + + if (aux->write_locked) { + dm_bufio_mark_buffer_dirty(to_buffer(b)); + bl_up_write(&aux->lock); + } else + bl_up_read(&aux->lock); + + dm_bufio_release_move(to_buffer(b), n); + return 0; +} + +int dm_bm_flush_and_unlock(struct dm_block_manager *bm, + struct dm_block *superblock) +{ + int r; + + r = dm_bufio_write_dirty_buffers(to_bufio(bm)); + if (unlikely(r)) + return r; + r = dm_bufio_issue_flush(to_bufio(bm)); + if (unlikely(r)) + return r; + + dm_bm_unlock(superblock); + + r = dm_bufio_write_dirty_buffers(to_bufio(bm)); + if (unlikely(r)) + return r; + r = dm_bufio_issue_flush(to_bufio(bm)); + if (unlikely(r)) + return r; + + return 0; +} + +u32 dm_bm_checksum(const void *data, size_t len, u32 init_xor) +{ + return crc32c(~(u32) 0, data, len) ^ init_xor; +} +EXPORT_SYMBOL_GPL(dm_bm_checksum); + +/*----------------------------------------------------------------*/ + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>"); +MODULE_DESCRIPTION("Immutable metadata library for dm"); + +/*----------------------------------------------------------------*/ diff --git a/drivers/md/persistent-data/dm-block-manager.h b/drivers/md/persistent-data/dm-block-manager.h new file mode 100644 index 00000000000..924833d2dfa --- /dev/null +++ b/drivers/md/persistent-data/dm-block-manager.h @@ -0,0 +1,123 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#ifndef _LINUX_DM_BLOCK_MANAGER_H +#define _LINUX_DM_BLOCK_MANAGER_H + +#include <linux/types.h> +#include <linux/blkdev.h> + +/*----------------------------------------------------------------*/ + +/* + * Block number. + */ +typedef uint64_t dm_block_t; +struct dm_block; + +dm_block_t dm_block_location(struct dm_block *b); +void *dm_block_data(struct dm_block *b); + +/*----------------------------------------------------------------*/ + +/* + * @name should be a unique identifier for the block manager, no longer + * than 32 chars. + * + * @max_held_per_thread should be the maximum number of locks, read or + * write, that an individual thread holds at any one time. + */ +struct dm_block_manager; +struct dm_block_manager *dm_block_manager_create( + struct block_device *bdev, unsigned block_size, + unsigned cache_size, unsigned max_held_per_thread); +void dm_block_manager_destroy(struct dm_block_manager *bm); + +unsigned dm_bm_block_size(struct dm_block_manager *bm); +dm_block_t dm_bm_nr_blocks(struct dm_block_manager *bm); + +/*----------------------------------------------------------------*/ + +/* + * The validator allows the caller to verify newly-read data and modify + * the data just before writing, e.g. to calculate checksums. It's + * important to be consistent with your use of validators. The only time + * you can change validators is if you call dm_bm_write_lock_zero. + */ +struct dm_block_validator { + const char *name; + void (*prepare_for_write)(struct dm_block_validator *v, struct dm_block *b, size_t block_size); + + /* + * Return 0 if the checksum is valid or < 0 on error. + */ + int (*check)(struct dm_block_validator *v, struct dm_block *b, size_t block_size); +}; + +/*----------------------------------------------------------------*/ + +/* + * You can have multiple concurrent readers or a single writer holding a + * block lock. + */ + +/* + * dm_bm_lock() locks a block and returns through @result a pointer to + * memory that holds a copy of that block. If you have write-locked the + * block then any changes you make to memory pointed to by @result will be + * written back to the disk sometime after dm_bm_unlock is called. + */ +int dm_bm_read_lock(struct dm_block_manager *bm, dm_block_t b, + struct dm_block_validator *v, + struct dm_block **result); + +int dm_bm_write_lock(struct dm_block_manager *bm, dm_block_t b, + struct dm_block_validator *v, + struct dm_block **result); + +/* + * The *_try_lock variants return -EWOULDBLOCK if the block isn't + * available immediately. + */ +int dm_bm_read_try_lock(struct dm_block_manager *bm, dm_block_t b, + struct dm_block_validator *v, + struct dm_block **result); + +/* + * Use dm_bm_write_lock_zero() when you know you're going to + * overwrite the block completely. It saves a disk read. + */ +int dm_bm_write_lock_zero(struct dm_block_manager *bm, dm_block_t b, + struct dm_block_validator *v, + struct dm_block **result); + +int dm_bm_unlock(struct dm_block *b); + +/* + * An optimisation; we often want to copy a block's contents to a new + * block. eg, as part of the shadowing operation. It's far better for + * bufio to do this move behind the scenes than hold 2 locks and memcpy the + * data. + */ +int dm_bm_unlock_move(struct dm_block *b, dm_block_t n); + +/* + * It's a common idiom to have a superblock that should be committed last. + * + * @superblock should be write-locked on entry. It will be unlocked during + * this function. All dirty blocks are guaranteed to be written and flushed + * before the superblock. + * + * This method always blocks. + */ +int dm_bm_flush_and_unlock(struct dm_block_manager *bm, + struct dm_block *superblock); + +u32 dm_bm_checksum(const void *data, size_t len, u32 init_xor); + +/*----------------------------------------------------------------*/ + +#endif /* _LINUX_DM_BLOCK_MANAGER_H */ diff --git a/drivers/md/persistent-data/dm-btree-internal.h b/drivers/md/persistent-data/dm-btree-internal.h new file mode 100644 index 00000000000..d279c768f8f --- /dev/null +++ b/drivers/md/persistent-data/dm-btree-internal.h @@ -0,0 +1,137 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#ifndef DM_BTREE_INTERNAL_H +#define DM_BTREE_INTERNAL_H + +#include "dm-btree.h" + +/*----------------------------------------------------------------*/ + +/* + * We'll need 2 accessor functions for n->csum and n->blocknr + * to support dm-btree-spine.c in that case. + */ + +enum node_flags { + INTERNAL_NODE = 1, + LEAF_NODE = 1 << 1 +}; + +/* + * Every btree node begins with this structure. Make sure it's a multiple + * of 8-bytes in size, otherwise the 64bit keys will be mis-aligned. + */ +struct node_header { + __le32 csum; + __le32 flags; + __le64 blocknr; /* Block this node is supposed to live in. */ + + __le32 nr_entries; + __le32 max_entries; + __le32 value_size; + __le32 padding; +} __packed; + +struct node { + struct node_header header; + __le64 keys[0]; +} __packed; + + +void inc_children(struct dm_transaction_manager *tm, struct node *n, + struct dm_btree_value_type *vt); + +int new_block(struct dm_btree_info *info, struct dm_block **result); +int unlock_block(struct dm_btree_info *info, struct dm_block *b); + +/* + * Spines keep track of the rolling locks. There are 2 variants, read-only + * and one that uses shadowing. These are separate structs to allow the + * type checker to spot misuse, for example accidentally calling read_lock + * on a shadow spine. + */ +struct ro_spine { + struct dm_btree_info *info; + + int count; + struct dm_block *nodes[2]; +}; + +void init_ro_spine(struct ro_spine *s, struct dm_btree_info *info); +int exit_ro_spine(struct ro_spine *s); +int ro_step(struct ro_spine *s, dm_block_t new_child); +struct node *ro_node(struct ro_spine *s); + +struct shadow_spine { + struct dm_btree_info *info; + + int count; + struct dm_block *nodes[2]; + + dm_block_t root; +}; + +void init_shadow_spine(struct shadow_spine *s, struct dm_btree_info *info); +int exit_shadow_spine(struct shadow_spine *s); + +int shadow_step(struct shadow_spine *s, dm_block_t b, + struct dm_btree_value_type *vt); + +/* + * The spine must have at least one entry before calling this. + */ +struct dm_block *shadow_current(struct shadow_spine *s); + +/* + * The spine must have at least two entries before calling this. + */ +struct dm_block *shadow_parent(struct shadow_spine *s); + +int shadow_has_parent(struct shadow_spine *s); + +int shadow_root(struct shadow_spine *s); + +/* + * Some inlines. + */ +static inline __le64 *key_ptr(struct node *n, uint32_t index) +{ + return n->keys + index; +} + +static inline void *value_base(struct node *n) +{ + return &n->keys[le32_to_cpu(n->header.max_entries)]; +} + +/* + * FIXME: Now that value size is stored in node we don't need the third parm. + */ +static inline void *value_ptr(struct node *n, uint32_t index, size_t value_size) +{ + BUG_ON(value_size != le32_to_cpu(n->header.value_size)); + return value_base(n) + (value_size * index); +} + +/* + * Assumes the values are suitably-aligned and converts to core format. + */ +static inline uint64_t value64(struct node *n, uint32_t index) +{ + __le64 *values_le = value_base(n); + + return le64_to_cpu(values_le[index]); +} + +/* + * Searching for a key within a single node. + */ +int lower_bound(struct node *n, uint64_t key); + +extern struct dm_block_validator btree_node_validator; + +#endif /* DM_BTREE_INTERNAL_H */ diff --git a/drivers/md/persistent-data/dm-btree-remove.c b/drivers/md/persistent-data/dm-btree-remove.c new file mode 100644 index 00000000000..65fd85ec651 --- /dev/null +++ b/drivers/md/persistent-data/dm-btree-remove.c @@ -0,0 +1,566 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#include "dm-btree.h" +#include "dm-btree-internal.h" +#include "dm-transaction-manager.h" + +#include <linux/module.h> + +/* + * Removing an entry from a btree + * ============================== + * + * A very important constraint for our btree is that no node, except the + * root, may have fewer than a certain number of entries. + * (MIN_ENTRIES <= nr_entries <= MAX_ENTRIES). + * + * Ensuring this is complicated by the way we want to only ever hold the + * locks on 2 nodes concurrently, and only change nodes in a top to bottom + * fashion. + * + * Each node may have a left or right sibling. When decending the spine, + * if a node contains only MIN_ENTRIES then we try and increase this to at + * least MIN_ENTRIES + 1. We do this in the following ways: + * + * [A] No siblings => this can only happen if the node is the root, in which + * case we copy the childs contents over the root. + * + * [B] No left sibling + * ==> rebalance(node, right sibling) + * + * [C] No right sibling + * ==> rebalance(left sibling, node) + * + * [D] Both siblings, total_entries(left, node, right) <= DEL_THRESHOLD + * ==> delete node adding it's contents to left and right + * + * [E] Both siblings, total_entries(left, node, right) > DEL_THRESHOLD + * ==> rebalance(left, node, right) + * + * After these operations it's possible that the our original node no + * longer contains the desired sub tree. For this reason this rebalancing + * is performed on the children of the current node. This also avoids + * having a special case for the root. + * + * Once this rebalancing has occurred we can then step into the child node + * for internal nodes. Or delete the entry for leaf nodes. + */ + +/* + * Some little utilities for moving node data around. + */ +static void node_shift(struct node *n, int shift) +{ + uint32_t nr_entries = le32_to_cpu(n->header.nr_entries); + uint32_t value_size = le32_to_cpu(n->header.value_size); + + if (shift < 0) { + shift = -shift; + BUG_ON(shift > nr_entries); + BUG_ON((void *) key_ptr(n, shift) >= value_ptr(n, shift, value_size)); + memmove(key_ptr(n, 0), + key_ptr(n, shift), + (nr_entries - shift) * sizeof(__le64)); + memmove(value_ptr(n, 0, value_size), + value_ptr(n, shift, value_size), + (nr_entries - shift) * value_size); + } else { + BUG_ON(nr_entries + shift > le32_to_cpu(n->header.max_entries)); + memmove(key_ptr(n, shift), + key_ptr(n, 0), + nr_entries * sizeof(__le64)); + memmove(value_ptr(n, shift, value_size), + value_ptr(n, 0, value_size), + nr_entries * value_size); + } +} + +static void node_copy(struct node *left, struct node *right, int shift) +{ + uint32_t nr_left = le32_to_cpu(left->header.nr_entries); + uint32_t value_size = le32_to_cpu(left->header.value_size); + BUG_ON(value_size != le32_to_cpu(right->header.value_size)); + + if (shift < 0) { + shift = -shift; + BUG_ON(nr_left + shift > le32_to_cpu(left->header.max_entries)); + memcpy(key_ptr(left, nr_left), + key_ptr(right, 0), + shift * sizeof(__le64)); + memcpy(value_ptr(left, nr_left, value_size), + value_ptr(right, 0, value_size), + shift * value_size); + } else { + BUG_ON(shift > le32_to_cpu(right->header.max_entries)); + memcpy(key_ptr(right, 0), + key_ptr(left, nr_left - shift), + shift * sizeof(__le64)); + memcpy(value_ptr(right, 0, value_size), + value_ptr(left, nr_left - shift, value_size), + shift * value_size); + } +} + +/* + * Delete a specific entry from a leaf node. + */ +static void delete_at(struct node *n, unsigned index) +{ + unsigned nr_entries = le32_to_cpu(n->header.nr_entries); + unsigned nr_to_copy = nr_entries - (index + 1); + uint32_t value_size = le32_to_cpu(n->header.value_size); + BUG_ON(index >= nr_entries); + + if (nr_to_copy) { + memmove(key_ptr(n, index), + key_ptr(n, index + 1), + nr_to_copy * sizeof(__le64)); + + memmove(value_ptr(n, index, value_size), + value_ptr(n, index + 1, value_size), + nr_to_copy * value_size); + } + + n->header.nr_entries = cpu_to_le32(nr_entries - 1); +} + +static unsigned del_threshold(struct node *n) +{ + return le32_to_cpu(n->header.max_entries) / 3; +} + +static unsigned merge_threshold(struct node *n) +{ + /* + * The extra one is because we know we're potentially going to + * delete an entry. + */ + return 2 * (le32_to_cpu(n->header.max_entries) / 3) + 1; +} + +struct child { + unsigned index; + struct dm_block *block; + struct node *n; +}; + +static struct dm_btree_value_type le64_type = { + .context = NULL, + .size = sizeof(__le64), + .inc = NULL, + .dec = NULL, + .equal = NULL +}; + +static int init_child(struct dm_btree_info *info, struct node *parent, + unsigned index, struct child *result) +{ + int r, inc; + dm_block_t root; + + result->index = index; + root = value64(parent, index); + + r = dm_tm_shadow_block(info->tm, root, &btree_node_validator, + &result->block, &inc); + if (r) + return r; + + result->n = dm_block_data(result->block); + + if (inc) + inc_children(info->tm, result->n, &le64_type); + + *((__le64 *) value_ptr(parent, index, sizeof(__le64))) = + cpu_to_le64(dm_block_location(result->block)); + + return 0; +} + +static int exit_child(struct dm_btree_info *info, struct child *c) +{ + return dm_tm_unlock(info->tm, c->block); +} + +static void shift(struct node *left, struct node *right, int count) +{ + if (!count) + return; + + if (count > 0) { + node_shift(right, count); + node_copy(left, right, count); + } else { + node_copy(left, right, count); + node_shift(right, count); + } + + left->header.nr_entries = + cpu_to_le32(le32_to_cpu(left->header.nr_entries) - count); + BUG_ON(le32_to_cpu(left->header.nr_entries) > le32_to_cpu(left->header.max_entries)); + + right->header.nr_entries = + cpu_to_le32(le32_to_cpu(right->header.nr_entries) + count); + BUG_ON(le32_to_cpu(right->header.nr_entries) > le32_to_cpu(right->header.max_entries)); +} + +static void __rebalance2(struct dm_btree_info *info, struct node *parent, + struct child *l, struct child *r) +{ + struct node *left = l->n; + struct node *right = r->n; + uint32_t nr_left = le32_to_cpu(left->header.nr_entries); + uint32_t nr_right = le32_to_cpu(right->header.nr_entries); + + if (nr_left + nr_right <= merge_threshold(left)) { + /* + * Merge + */ + node_copy(left, right, -nr_right); + left->header.nr_entries = cpu_to_le32(nr_left + nr_right); + delete_at(parent, r->index); + + /* + * We need to decrement the right block, but not it's + * children, since they're still referenced by left. + */ + dm_tm_dec(info->tm, dm_block_location(r->block)); + } else { + /* + * Rebalance. + */ + unsigned target_left = (nr_left + nr_right) / 2; + unsigned shift_ = nr_left - target_left; + BUG_ON(le32_to_cpu(left->header.max_entries) <= nr_left - shift_); + BUG_ON(le32_to_cpu(right->header.max_entries) <= nr_right + shift_); + shift(left, right, nr_left - target_left); + *key_ptr(parent, r->index) = right->keys[0]; + } +} + +static int rebalance2(struct shadow_spine *s, struct dm_btree_info *info, + unsigned left_index) +{ + int r; + struct node *parent; + struct child left, right; + + parent = dm_block_data(shadow_current(s)); + + r = init_child(info, parent, left_index, &left); + if (r) + return r; + + r = init_child(info, parent, left_index + 1, &right); + if (r) { + exit_child(info, &left); + return r; + } + + __rebalance2(info, parent, &left, &right); + + r = exit_child(info, &left); + if (r) { + exit_child(info, &right); + return r; + } + + return exit_child(info, &right); +} + +static void __rebalance3(struct dm_btree_info *info, struct node *parent, + struct child *l, struct child *c, struct child *r) +{ + struct node *left = l->n; + struct node *center = c->n; + struct node *right = r->n; + + uint32_t nr_left = le32_to_cpu(left->header.nr_entries); + uint32_t nr_center = le32_to_cpu(center->header.nr_entries); + uint32_t nr_right = le32_to_cpu(right->header.nr_entries); + uint32_t max_entries = le32_to_cpu(left->header.max_entries); + + unsigned target; + + BUG_ON(left->header.max_entries != center->header.max_entries); + BUG_ON(center->header.max_entries != right->header.max_entries); + + if (((nr_left + nr_center + nr_right) / 2) < merge_threshold(center)) { + /* + * Delete center node: + * + * We dump as many entries from center as possible into + * left, then the rest in right, then rebalance2. This + * wastes some cpu, but I want something simple atm. + */ + unsigned shift = min(max_entries - nr_left, nr_center); + + BUG_ON(nr_left + shift > max_entries); + node_copy(left, center, -shift); + left->header.nr_entries = cpu_to_le32(nr_left + shift); + + if (shift != nr_center) { + shift = nr_center - shift; + BUG_ON((nr_right + shift) >= max_entries); + node_shift(right, shift); + node_copy(center, right, shift); + right->header.nr_entries = cpu_to_le32(nr_right + shift); + } + *key_ptr(parent, r->index) = right->keys[0]; + + delete_at(parent, c->index); + r->index--; + + dm_tm_dec(info->tm, dm_block_location(c->block)); + __rebalance2(info, parent, l, r); + + return; + } + + /* + * Rebalance + */ + target = (nr_left + nr_center + nr_right) / 3; + BUG_ON(target > max_entries); + + /* + * Adjust the left node + */ + shift(left, center, nr_left - target); + + /* + * Adjust the right node + */ + shift(center, right, target - nr_right); + *key_ptr(parent, c->index) = center->keys[0]; + *key_ptr(parent, r->index) = right->keys[0]; +} + +static int rebalance3(struct shadow_spine *s, struct dm_btree_info *info, + unsigned left_index) +{ + int r; + struct node *parent = dm_block_data(shadow_current(s)); + struct child left, center, right; + + /* + * FIXME: fill out an array? + */ + r = init_child(info, parent, left_index, &left); + if (r) + return r; + + r = init_child(info, parent, left_index + 1, ¢er); + if (r) { + exit_child(info, &left); + return r; + } + + r = init_child(info, parent, left_index + 2, &right); + if (r) { + exit_child(info, &left); + exit_child(info, ¢er); + return r; + } + + __rebalance3(info, parent, &left, ¢er, &right); + + r = exit_child(info, &left); + if (r) { + exit_child(info, ¢er); + exit_child(info, &right); + return r; + } + + r = exit_child(info, ¢er); + if (r) { + exit_child(info, &right); + return r; + } + + r = exit_child(info, &right); + if (r) + return r; + + return 0; +} + +static int get_nr_entries(struct dm_transaction_manager *tm, + dm_block_t b, uint32_t *result) +{ + int r; + struct dm_block *block; + struct node *n; + + r = dm_tm_read_lock(tm, b, &btree_node_validator, &block); + if (r) + return r; + + n = dm_block_data(block); + *result = le32_to_cpu(n->header.nr_entries); + + return dm_tm_unlock(tm, block); +} + +static int rebalance_children(struct shadow_spine *s, + struct dm_btree_info *info, uint64_t key) +{ + int i, r, has_left_sibling, has_right_sibling; + uint32_t child_entries; + struct node *n; + + n = dm_block_data(shadow_current(s)); + + if (le32_to_cpu(n->header.nr_entries) == 1) { + struct dm_block *child; + dm_block_t b = value64(n, 0); + + r = dm_tm_read_lock(info->tm, b, &btree_node_validator, &child); + if (r) + return r; + + memcpy(n, dm_block_data(child), + dm_bm_block_size(dm_tm_get_bm(info->tm))); + r = dm_tm_unlock(info->tm, child); + if (r) + return r; + + dm_tm_dec(info->tm, dm_block_location(child)); + return 0; + } + + i = lower_bound(n, key); + if (i < 0) + return -ENODATA; + + r = get_nr_entries(info->tm, value64(n, i), &child_entries); + if (r) + return r; + + if (child_entries > del_threshold(n)) + return 0; + + has_left_sibling = i > 0; + has_right_sibling = i < (le32_to_cpu(n->header.nr_entries) - 1); + + if (!has_left_sibling) + r = rebalance2(s, info, i); + + else if (!has_right_sibling) + r = rebalance2(s, info, i - 1); + + else + r = rebalance3(s, info, i - 1); + + return r; +} + +static int do_leaf(struct node *n, uint64_t key, unsigned *index) +{ + int i = lower_bound(n, key); + + if ((i < 0) || + (i >= le32_to_cpu(n->header.nr_entries)) || + (le64_to_cpu(n->keys[i]) != key)) + return -ENODATA; + + *index = i; + + return 0; +} + +/* + * Prepares for removal from one level of the hierarchy. The caller must + * call delete_at() to remove the entry at index. + */ +static int remove_raw(struct shadow_spine *s, struct dm_btree_info *info, + struct dm_btree_value_type *vt, dm_block_t root, + uint64_t key, unsigned *index) +{ + int i = *index, r; + struct node *n; + + for (;;) { + r = shadow_step(s, root, vt); + if (r < 0) + break; + + /* + * We have to patch up the parent node, ugly, but I don't + * see a way to do this automatically as part of the spine + * op. + */ + if (shadow_has_parent(s)) { + __le64 location = cpu_to_le64(dm_block_location(shadow_current(s))); + memcpy(value_ptr(dm_block_data(shadow_parent(s)), i, sizeof(__le64)), + &location, sizeof(__le64)); + } + + n = dm_block_data(shadow_current(s)); + + if (le32_to_cpu(n->header.flags) & LEAF_NODE) + return do_leaf(n, key, index); + + r = rebalance_children(s, info, key); + if (r) + break; + + n = dm_block_data(shadow_current(s)); + if (le32_to_cpu(n->header.flags) & LEAF_NODE) + return do_leaf(n, key, index); + + i = lower_bound(n, key); + + /* + * We know the key is present, or else + * rebalance_children would have returned + * -ENODATA + */ + root = value64(n, i); + } + + return r; +} + +int dm_btree_remove(struct dm_btree_info *info, dm_block_t root, + uint64_t *keys, dm_block_t *new_root) +{ + unsigned level, last_level = info->levels - 1; + int index = 0, r = 0; + struct shadow_spine spine; + struct node *n; + + init_shadow_spine(&spine, info); + for (level = 0; level < info->levels; level++) { + r = remove_raw(&spine, info, + (level == last_level ? + &info->value_type : &le64_type), + root, keys[level], (unsigned *)&index); + if (r < 0) + break; + + n = dm_block_data(shadow_current(&spine)); + if (level != last_level) { + root = value64(n, index); + continue; + } + + BUG_ON(index < 0 || index >= le32_to_cpu(n->header.nr_entries)); + + if (info->value_type.dec) + info->value_type.dec(info->value_type.context, + value_ptr(n, index, info->value_type.size)); + + delete_at(n, index); + } + + *new_root = shadow_root(&spine); + exit_shadow_spine(&spine); + + return r; +} +EXPORT_SYMBOL_GPL(dm_btree_remove); diff --git a/drivers/md/persistent-data/dm-btree-spine.c b/drivers/md/persistent-data/dm-btree-spine.c new file mode 100644 index 00000000000..d9a7912ee8e --- /dev/null +++ b/drivers/md/persistent-data/dm-btree-spine.c @@ -0,0 +1,244 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#include "dm-btree-internal.h" +#include "dm-transaction-manager.h" + +#include <linux/device-mapper.h> + +#define DM_MSG_PREFIX "btree spine" + +/*----------------------------------------------------------------*/ + +#define BTREE_CSUM_XOR 121107 + +static int node_check(struct dm_block_validator *v, + struct dm_block *b, + size_t block_size); + +static void node_prepare_for_write(struct dm_block_validator *v, + struct dm_block *b, + size_t block_size) +{ + struct node *n = dm_block_data(b); + struct node_header *h = &n->header; + + h->blocknr = cpu_to_le64(dm_block_location(b)); + h->csum = cpu_to_le32(dm_bm_checksum(&h->flags, + block_size - sizeof(__le32), + BTREE_CSUM_XOR)); + + BUG_ON(node_check(v, b, 4096)); +} + +static int node_check(struct dm_block_validator *v, + struct dm_block *b, + size_t block_size) +{ + struct node *n = dm_block_data(b); + struct node_header *h = &n->header; + size_t value_size; + __le32 csum_disk; + uint32_t flags; + + if (dm_block_location(b) != le64_to_cpu(h->blocknr)) { + DMERR("node_check failed blocknr %llu wanted %llu", + le64_to_cpu(h->blocknr), dm_block_location(b)); + return -ENOTBLK; + } + + csum_disk = cpu_to_le32(dm_bm_checksum(&h->flags, + block_size - sizeof(__le32), + BTREE_CSUM_XOR)); + if (csum_disk != h->csum) { + DMERR("node_check failed csum %u wanted %u", + le32_to_cpu(csum_disk), le32_to_cpu(h->csum)); + return -EILSEQ; + } + + value_size = le32_to_cpu(h->value_size); + + if (sizeof(struct node_header) + + (sizeof(__le64) + value_size) * le32_to_cpu(h->max_entries) > block_size) { + DMERR("node_check failed: max_entries too large"); + return -EILSEQ; + } + + if (le32_to_cpu(h->nr_entries) > le32_to_cpu(h->max_entries)) { + DMERR("node_check failed, too many entries"); + return -EILSEQ; + } + + /* + * The node must be either INTERNAL or LEAF. + */ + flags = le32_to_cpu(h->flags); + if (!(flags & INTERNAL_NODE) && !(flags & LEAF_NODE)) { + DMERR("node_check failed, node is neither INTERNAL or LEAF"); + return -EILSEQ; + } + + return 0; +} + +struct dm_block_validator btree_node_validator = { + .name = "btree_node", + .prepare_for_write = node_prepare_for_write, + .check = node_check +}; + +/*----------------------------------------------------------------*/ + +static int bn_read_lock(struct dm_btree_info *info, dm_block_t b, + struct dm_block **result) +{ + return dm_tm_read_lock(info->tm, b, &btree_node_validator, result); +} + +static int bn_shadow(struct dm_btree_info *info, dm_block_t orig, + struct dm_btree_value_type *vt, + struct dm_block **result) +{ + int r, inc; + + r = dm_tm_shadow_block(info->tm, orig, &btree_node_validator, + result, &inc); + if (!r && inc) + inc_children(info->tm, dm_block_data(*result), vt); + + return r; +} + +int new_block(struct dm_btree_info *info, struct dm_block **result) +{ + return dm_tm_new_block(info->tm, &btree_node_validator, result); +} + +int unlock_block(struct dm_btree_info *info, struct dm_block *b) +{ + return dm_tm_unlock(info->tm, b); +} + +/*----------------------------------------------------------------*/ + +void init_ro_spine(struct ro_spine *s, struct dm_btree_info *info) +{ + s->info = info; + s->count = 0; + s->nodes[0] = NULL; + s->nodes[1] = NULL; +} + +int exit_ro_spine(struct ro_spine *s) +{ + int r = 0, i; + + for (i = 0; i < s->count; i++) { + int r2 = unlock_block(s->info, s->nodes[i]); + if (r2 < 0) + r = r2; + } + + return r; +} + +int ro_step(struct ro_spine *s, dm_block_t new_child) +{ + int r; + + if (s->count == 2) { + r = unlock_block(s->info, s->nodes[0]); + if (r < 0) + return r; + s->nodes[0] = s->nodes[1]; + s->count--; + } + + r = bn_read_lock(s->info, new_child, s->nodes + s->count); + if (!r) + s->count++; + + return r; +} + +struct node *ro_node(struct ro_spine *s) +{ + struct dm_block *block; + + BUG_ON(!s->count); + block = s->nodes[s->count - 1]; + + return dm_block_data(block); +} + +/*----------------------------------------------------------------*/ + +void init_shadow_spine(struct shadow_spine *s, struct dm_btree_info *info) +{ + s->info = info; + s->count = 0; +} + +int exit_shadow_spine(struct shadow_spine *s) +{ + int r = 0, i; + + for (i = 0; i < s->count; i++) { + int r2 = unlock_block(s->info, s->nodes[i]); + if (r2 < 0) + r = r2; + } + + return r; +} + +int shadow_step(struct shadow_spine *s, dm_block_t b, + struct dm_btree_value_type *vt) +{ + int r; + + if (s->count == 2) { + r = unlock_block(s->info, s->nodes[0]); + if (r < 0) + return r; + s->nodes[0] = s->nodes[1]; + s->count--; + } + + r = bn_shadow(s->info, b, vt, s->nodes + s->count); + if (!r) { + if (!s->count) + s->root = dm_block_location(s->nodes[0]); + + s->count++; + } + + return r; +} + +struct dm_block *shadow_current(struct shadow_spine *s) +{ + BUG_ON(!s->count); + + return s->nodes[s->count - 1]; +} + +struct dm_block *shadow_parent(struct shadow_spine *s) +{ + BUG_ON(s->count != 2); + + return s->count == 2 ? s->nodes[0] : NULL; +} + +int shadow_has_parent(struct shadow_spine *s) +{ + return s->count >= 2; +} + +int shadow_root(struct shadow_spine *s) +{ + return s->root; +} diff --git a/drivers/md/persistent-data/dm-btree.c b/drivers/md/persistent-data/dm-btree.c new file mode 100644 index 00000000000..e0638be53ea --- /dev/null +++ b/drivers/md/persistent-data/dm-btree.c @@ -0,0 +1,805 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#include "dm-btree-internal.h" +#include "dm-space-map.h" +#include "dm-transaction-manager.h" + +#include <linux/module.h> +#include <linux/device-mapper.h> + +#define DM_MSG_PREFIX "btree" + +/*---------------------------------------------------------------- + * Array manipulation + *--------------------------------------------------------------*/ +static void memcpy_disk(void *dest, const void *src, size_t len) + __dm_written_to_disk(src) +{ + memcpy(dest, src, len); + __dm_unbless_for_disk(src); +} + +static void array_insert(void *base, size_t elt_size, unsigned nr_elts, + unsigned index, void *elt) + __dm_written_to_disk(elt) +{ + if (index < nr_elts) + memmove(base + (elt_size * (index + 1)), + base + (elt_size * index), + (nr_elts - index) * elt_size); + + memcpy_disk(base + (elt_size * index), elt, elt_size); +} + +/*----------------------------------------------------------------*/ + +/* makes the assumption that no two keys are the same. */ +static int bsearch(struct node *n, uint64_t key, int want_hi) +{ + int lo = -1, hi = le32_to_cpu(n->header.nr_entries); + + while (hi - lo > 1) { + int mid = lo + ((hi - lo) / 2); + uint64_t mid_key = le64_to_cpu(n->keys[mid]); + + if (mid_key == key) + return mid; + + if (mid_key < key) + lo = mid; + else + hi = mid; + } + + return want_hi ? hi : lo; +} + +int lower_bound(struct node *n, uint64_t key) +{ + return bsearch(n, key, 0); +} + +void inc_children(struct dm_transaction_manager *tm, struct node *n, + struct dm_btree_value_type *vt) +{ + unsigned i; + uint32_t nr_entries = le32_to_cpu(n->header.nr_entries); + + if (le32_to_cpu(n->header.flags) & INTERNAL_NODE) + for (i = 0; i < nr_entries; i++) + dm_tm_inc(tm, value64(n, i)); + else if (vt->inc) + for (i = 0; i < nr_entries; i++) + vt->inc(vt->context, + value_ptr(n, i, vt->size)); +} + +static int insert_at(size_t value_size, struct node *node, unsigned index, + uint64_t key, void *value) + __dm_written_to_disk(value) +{ + uint32_t nr_entries = le32_to_cpu(node->header.nr_entries); + __le64 key_le = cpu_to_le64(key); + + if (index > nr_entries || + index >= le32_to_cpu(node->header.max_entries)) { + DMERR("too many entries in btree node for insert"); + __dm_unbless_for_disk(value); + return -ENOMEM; + } + + __dm_bless_for_disk(&key_le); + + array_insert(node->keys, sizeof(*node->keys), nr_entries, index, &key_le); + array_insert(value_base(node), value_size, nr_entries, index, value); + node->header.nr_entries = cpu_to_le32(nr_entries + 1); + + return 0; +} + +/*----------------------------------------------------------------*/ + +/* + * We want 3n entries (for some n). This works more nicely for repeated + * insert remove loops than (2n + 1). + */ +static uint32_t calc_max_entries(size_t value_size, size_t block_size) +{ + uint32_t total, n; + size_t elt_size = sizeof(uint64_t) + value_size; /* key + value */ + + block_size -= sizeof(struct node_header); + total = block_size / elt_size; + n = total / 3; /* rounds down */ + + return 3 * n; +} + +int dm_btree_empty(struct dm_btree_info *info, dm_block_t *root) +{ + int r; + struct dm_block *b; + struct node *n; + size_t block_size; + uint32_t max_entries; + + r = new_block(info, &b); + if (r < 0) + return r; + + block_size = dm_bm_block_size(dm_tm_get_bm(info->tm)); + max_entries = calc_max_entries(info->value_type.size, block_size); + + n = dm_block_data(b); + memset(n, 0, block_size); + n->header.flags = cpu_to_le32(LEAF_NODE); + n->header.nr_entries = cpu_to_le32(0); + n->header.max_entries = cpu_to_le32(max_entries); + n->header.value_size = cpu_to_le32(info->value_type.size); + + *root = dm_block_location(b); + return unlock_block(info, b); +} +EXPORT_SYMBOL_GPL(dm_btree_empty); + +/*----------------------------------------------------------------*/ + +/* + * Deletion uses a recursive algorithm, since we have limited stack space + * we explicitly manage our own stack on the heap. + */ +#define MAX_SPINE_DEPTH 64 +struct frame { + struct dm_block *b; + struct node *n; + unsigned level; + unsigned nr_children; + unsigned current_child; +}; + +struct del_stack { + struct dm_transaction_manager *tm; + int top; + struct frame spine[MAX_SPINE_DEPTH]; +}; + +static int top_frame(struct del_stack *s, struct frame **f) +{ + if (s->top < 0) { + DMERR("btree deletion stack empty"); + return -EINVAL; + } + + *f = s->spine + s->top; + + return 0; +} + +static int unprocessed_frames(struct del_stack *s) +{ + return s->top >= 0; +} + +static int push_frame(struct del_stack *s, dm_block_t b, unsigned level) +{ + int r; + uint32_t ref_count; + + if (s->top >= MAX_SPINE_DEPTH - 1) { + DMERR("btree deletion stack out of memory"); + return -ENOMEM; + } + + r = dm_tm_ref(s->tm, b, &ref_count); + if (r) + return r; + + if (ref_count > 1) + /* + * This is a shared node, so we can just decrement it's + * reference counter and leave the children. + */ + dm_tm_dec(s->tm, b); + + else { + struct frame *f = s->spine + ++s->top; + + r = dm_tm_read_lock(s->tm, b, &btree_node_validator, &f->b); + if (r) { + s->top--; + return r; + } + + f->n = dm_block_data(f->b); + f->level = level; + f->nr_children = le32_to_cpu(f->n->header.nr_entries); + f->current_child = 0; + } + + return 0; +} + +static void pop_frame(struct del_stack *s) +{ + struct frame *f = s->spine + s->top--; + + dm_tm_dec(s->tm, dm_block_location(f->b)); + dm_tm_unlock(s->tm, f->b); +} + +int dm_btree_del(struct dm_btree_info *info, dm_block_t root) +{ + int r; + struct del_stack *s; + + s = kmalloc(sizeof(*s), GFP_KERNEL); + if (!s) + return -ENOMEM; + s->tm = info->tm; + s->top = -1; + + r = push_frame(s, root, 1); + if (r) + goto out; + + while (unprocessed_frames(s)) { + uint32_t flags; + struct frame *f; + dm_block_t b; + + r = top_frame(s, &f); + if (r) + goto out; + + if (f->current_child >= f->nr_children) { + pop_frame(s); + continue; + } + + flags = le32_to_cpu(f->n->header.flags); + if (flags & INTERNAL_NODE) { + b = value64(f->n, f->current_child); + f->current_child++; + r = push_frame(s, b, f->level); + if (r) + goto out; + + } else if (f->level != (info->levels - 1)) { + b = value64(f->n, f->current_child); + f->current_child++; + r = push_frame(s, b, f->level + 1); + if (r) + goto out; + + } else { + if (info->value_type.dec) { + unsigned i; + + for (i = 0; i < f->nr_children; i++) + info->value_type.dec(info->value_type.context, + value_ptr(f->n, i, info->value_type.size)); + } + f->current_child = f->nr_children; + } + } + +out: + kfree(s); + return r; +} +EXPORT_SYMBOL_GPL(dm_btree_del); + +/*----------------------------------------------------------------*/ + +static int btree_lookup_raw(struct ro_spine *s, dm_block_t block, uint64_t key, + int (*search_fn)(struct node *, uint64_t), + uint64_t *result_key, void *v, size_t value_size) +{ + int i, r; + uint32_t flags, nr_entries; + + do { + r = ro_step(s, block); + if (r < 0) + return r; + + i = search_fn(ro_node(s), key); + + flags = le32_to_cpu(ro_node(s)->header.flags); + nr_entries = le32_to_cpu(ro_node(s)->header.nr_entries); + if (i < 0 || i >= nr_entries) + return -ENODATA; + + if (flags & INTERNAL_NODE) + block = value64(ro_node(s), i); + + } while (!(flags & LEAF_NODE)); + + *result_key = le64_to_cpu(ro_node(s)->keys[i]); + memcpy(v, value_ptr(ro_node(s), i, value_size), value_size); + + return 0; +} + +int dm_btree_lookup(struct dm_btree_info *info, dm_block_t root, + uint64_t *keys, void *value_le) +{ + unsigned level, last_level = info->levels - 1; + int r = -ENODATA; + uint64_t rkey; + __le64 internal_value_le; + struct ro_spine spine; + + init_ro_spine(&spine, info); + for (level = 0; level < info->levels; level++) { + size_t size; + void *value_p; + + if (level == last_level) { + value_p = value_le; + size = info->value_type.size; + + } else { + value_p = &internal_value_le; + size = sizeof(uint64_t); + } + + r = btree_lookup_raw(&spine, root, keys[level], + lower_bound, &rkey, + value_p, size); + + if (!r) { + if (rkey != keys[level]) { + exit_ro_spine(&spine); + return -ENODATA; + } + } else { + exit_ro_spine(&spine); + return r; + } + + root = le64_to_cpu(internal_value_le); + } + exit_ro_spine(&spine); + + return r; +} +EXPORT_SYMBOL_GPL(dm_btree_lookup); + +/* + * Splits a node by creating a sibling node and shifting half the nodes + * contents across. Assumes there is a parent node, and it has room for + * another child. + * + * Before: + * +--------+ + * | Parent | + * +--------+ + * | + * v + * +----------+ + * | A ++++++ | + * +----------+ + * + * + * After: + * +--------+ + * | Parent | + * +--------+ + * | | + * v +------+ + * +---------+ | + * | A* +++ | v + * +---------+ +-------+ + * | B +++ | + * +-------+ + * + * Where A* is a shadow of A. + */ +static int btree_split_sibling(struct shadow_spine *s, dm_block_t root, + unsigned parent_index, uint64_t key) +{ + int r; + size_t size; + unsigned nr_left, nr_right; + struct dm_block *left, *right, *parent; + struct node *ln, *rn, *pn; + __le64 location; + + left = shadow_current(s); + + r = new_block(s->info, &right); + if (r < 0) + return r; + + ln = dm_block_data(left); + rn = dm_block_data(right); + + nr_left = le32_to_cpu(ln->header.nr_entries) / 2; + nr_right = le32_to_cpu(ln->header.nr_entries) - nr_left; + + ln->header.nr_entries = cpu_to_le32(nr_left); + + rn->header.flags = ln->header.flags; + rn->header.nr_entries = cpu_to_le32(nr_right); + rn->header.max_entries = ln->header.max_entries; + rn->header.value_size = ln->header.value_size; + memcpy(rn->keys, ln->keys + nr_left, nr_right * sizeof(rn->keys[0])); + + size = le32_to_cpu(ln->header.flags) & INTERNAL_NODE ? + sizeof(uint64_t) : s->info->value_type.size; + memcpy(value_ptr(rn, 0, size), value_ptr(ln, nr_left, size), + size * nr_right); + + /* + * Patch up the parent + */ + parent = shadow_parent(s); + + pn = dm_block_data(parent); + location = cpu_to_le64(dm_block_location(left)); + __dm_bless_for_disk(&location); + memcpy_disk(value_ptr(pn, parent_index, sizeof(__le64)), + &location, sizeof(__le64)); + + location = cpu_to_le64(dm_block_location(right)); + __dm_bless_for_disk(&location); + + r = insert_at(sizeof(__le64), pn, parent_index + 1, + le64_to_cpu(rn->keys[0]), &location); + if (r) + return r; + + if (key < le64_to_cpu(rn->keys[0])) { + unlock_block(s->info, right); + s->nodes[1] = left; + } else { + unlock_block(s->info, left); + s->nodes[1] = right; + } + + return 0; +} + +/* + * Splits a node by creating two new children beneath the given node. + * + * Before: + * +----------+ + * | A ++++++ | + * +----------+ + * + * + * After: + * +------------+ + * | A (shadow) | + * +------------+ + * | | + * +------+ +----+ + * | | + * v v + * +-------+ +-------+ + * | B +++ | | C +++ | + * +-------+ +-------+ + */ +static int btree_split_beneath(struct shadow_spine *s, uint64_t key) +{ + int r; + size_t size; + unsigned nr_left, nr_right; + struct dm_block *left, *right, *new_parent; + struct node *pn, *ln, *rn; + __le64 val; + + new_parent = shadow_current(s); + + r = new_block(s->info, &left); + if (r < 0) + return r; + + r = new_block(s->info, &right); + if (r < 0) { + /* FIXME: put left */ + return r; + } + + pn = dm_block_data(new_parent); + ln = dm_block_data(left); + rn = dm_block_data(right); + + nr_left = le32_to_cpu(pn->header.nr_entries) / 2; + nr_right = le32_to_cpu(pn->header.nr_entries) - nr_left; + + ln->header.flags = pn->header.flags; + ln->header.nr_entries = cpu_to_le32(nr_left); + ln->header.max_entries = pn->header.max_entries; + ln->header.value_size = pn->header.value_size; + + rn->header.flags = pn->header.flags; + rn->header.nr_entries = cpu_to_le32(nr_right); + rn->header.max_entries = pn->header.max_entries; + rn->header.value_size = pn->header.value_size; + + memcpy(ln->keys, pn->keys, nr_left * sizeof(pn->keys[0])); + memcpy(rn->keys, pn->keys + nr_left, nr_right * sizeof(pn->keys[0])); + + size = le32_to_cpu(pn->header.flags) & INTERNAL_NODE ? + sizeof(__le64) : s->info->value_type.size; + memcpy(value_ptr(ln, 0, size), value_ptr(pn, 0, size), nr_left * size); + memcpy(value_ptr(rn, 0, size), value_ptr(pn, nr_left, size), + nr_right * size); + + /* new_parent should just point to l and r now */ + pn->header.flags = cpu_to_le32(INTERNAL_NODE); + pn->header.nr_entries = cpu_to_le32(2); + pn->header.max_entries = cpu_to_le32( + calc_max_entries(sizeof(__le64), + dm_bm_block_size( + dm_tm_get_bm(s->info->tm)))); + pn->header.value_size = cpu_to_le32(sizeof(__le64)); + + val = cpu_to_le64(dm_block_location(left)); + __dm_bless_for_disk(&val); + pn->keys[0] = ln->keys[0]; + memcpy_disk(value_ptr(pn, 0, sizeof(__le64)), &val, sizeof(__le64)); + + val = cpu_to_le64(dm_block_location(right)); + __dm_bless_for_disk(&val); + pn->keys[1] = rn->keys[0]; + memcpy_disk(value_ptr(pn, 1, sizeof(__le64)), &val, sizeof(__le64)); + + /* + * rejig the spine. This is ugly, since it knows too + * much about the spine + */ + if (s->nodes[0] != new_parent) { + unlock_block(s->info, s->nodes[0]); + s->nodes[0] = new_parent; + } + if (key < le64_to_cpu(rn->keys[0])) { + unlock_block(s->info, right); + s->nodes[1] = left; + } else { + unlock_block(s->info, left); + s->nodes[1] = right; + } + s->count = 2; + + return 0; +} + +static int btree_insert_raw(struct shadow_spine *s, dm_block_t root, + struct dm_btree_value_type *vt, + uint64_t key, unsigned *index) +{ + int r, i = *index, top = 1; + struct node *node; + + for (;;) { + r = shadow_step(s, root, vt); + if (r < 0) + return r; + + node = dm_block_data(shadow_current(s)); + + /* + * We have to patch up the parent node, ugly, but I don't + * see a way to do this automatically as part of the spine + * op. + */ + if (shadow_has_parent(s) && i >= 0) { /* FIXME: second clause unness. */ + __le64 location = cpu_to_le64(dm_block_location(shadow_current(s))); + + __dm_bless_for_disk(&location); + memcpy_disk(value_ptr(dm_block_data(shadow_parent(s)), i, sizeof(uint64_t)), + &location, sizeof(__le64)); + } + + node = dm_block_data(shadow_current(s)); + + if (node->header.nr_entries == node->header.max_entries) { + if (top) + r = btree_split_beneath(s, key); + else + r = btree_split_sibling(s, root, i, key); + + if (r < 0) + return r; + } + + node = dm_block_data(shadow_current(s)); + + i = lower_bound(node, key); + + if (le32_to_cpu(node->header.flags) & LEAF_NODE) + break; + + if (i < 0) { + /* change the bounds on the lowest key */ + node->keys[0] = cpu_to_le64(key); + i = 0; + } + + root = value64(node, i); + top = 0; + } + + if (i < 0 || le64_to_cpu(node->keys[i]) != key) + i++; + + *index = i; + return 0; +} + +static int insert(struct dm_btree_info *info, dm_block_t root, + uint64_t *keys, void *value, dm_block_t *new_root, + int *inserted) + __dm_written_to_disk(value) +{ + int r, need_insert; + unsigned level, index = -1, last_level = info->levels - 1; + dm_block_t block = root; + struct shadow_spine spine; + struct node *n; + struct dm_btree_value_type le64_type; + + le64_type.context = NULL; + le64_type.size = sizeof(__le64); + le64_type.inc = NULL; + le64_type.dec = NULL; + le64_type.equal = NULL; + + init_shadow_spine(&spine, info); + + for (level = 0; level < (info->levels - 1); level++) { + r = btree_insert_raw(&spine, block, &le64_type, keys[level], &index); + if (r < 0) + goto bad; + + n = dm_block_data(shadow_current(&spine)); + need_insert = ((index >= le32_to_cpu(n->header.nr_entries)) || + (le64_to_cpu(n->keys[index]) != keys[level])); + + if (need_insert) { + dm_block_t new_tree; + __le64 new_le; + + r = dm_btree_empty(info, &new_tree); + if (r < 0) + goto bad; + + new_le = cpu_to_le64(new_tree); + __dm_bless_for_disk(&new_le); + + r = insert_at(sizeof(uint64_t), n, index, + keys[level], &new_le); + if (r) + goto bad; + } + + if (level < last_level) + block = value64(n, index); + } + + r = btree_insert_raw(&spine, block, &info->value_type, + keys[level], &index); + if (r < 0) + goto bad; + + n = dm_block_data(shadow_current(&spine)); + need_insert = ((index >= le32_to_cpu(n->header.nr_entries)) || + (le64_to_cpu(n->keys[index]) != keys[level])); + + if (need_insert) { + if (inserted) + *inserted = 1; + + r = insert_at(info->value_type.size, n, index, + keys[level], value); + if (r) + goto bad_unblessed; + } else { + if (inserted) + *inserted = 0; + + if (info->value_type.dec && + (!info->value_type.equal || + !info->value_type.equal( + info->value_type.context, + value_ptr(n, index, info->value_type.size), + value))) { + info->value_type.dec(info->value_type.context, + value_ptr(n, index, info->value_type.size)); + } + memcpy_disk(value_ptr(n, index, info->value_type.size), + value, info->value_type.size); + } + + *new_root = shadow_root(&spine); + exit_shadow_spine(&spine); + + return 0; + +bad: + __dm_unbless_for_disk(value); +bad_unblessed: + exit_shadow_spine(&spine); + return r; +} + +int dm_btree_insert(struct dm_btree_info *info, dm_block_t root, + uint64_t *keys, void *value, dm_block_t *new_root) + __dm_written_to_disk(value) +{ + return insert(info, root, keys, value, new_root, NULL); +} +EXPORT_SYMBOL_GPL(dm_btree_insert); + +int dm_btree_insert_notify(struct dm_btree_info *info, dm_block_t root, + uint64_t *keys, void *value, dm_block_t *new_root, + int *inserted) + __dm_written_to_disk(value) +{ + return insert(info, root, keys, value, new_root, inserted); +} +EXPORT_SYMBOL_GPL(dm_btree_insert_notify); + +/*----------------------------------------------------------------*/ + +static int find_highest_key(struct ro_spine *s, dm_block_t block, + uint64_t *result_key, dm_block_t *next_block) +{ + int i, r; + uint32_t flags; + + do { + r = ro_step(s, block); + if (r < 0) + return r; + + flags = le32_to_cpu(ro_node(s)->header.flags); + i = le32_to_cpu(ro_node(s)->header.nr_entries); + if (!i) + return -ENODATA; + else + i--; + + *result_key = le64_to_cpu(ro_node(s)->keys[i]); + if (next_block || flags & INTERNAL_NODE) + block = value64(ro_node(s), i); + + } while (flags & INTERNAL_NODE); + + if (next_block) + *next_block = block; + return 0; +} + +int dm_btree_find_highest_key(struct dm_btree_info *info, dm_block_t root, + uint64_t *result_keys) +{ + int r = 0, count = 0, level; + struct ro_spine spine; + + init_ro_spine(&spine, info); + for (level = 0; level < info->levels; level++) { + r = find_highest_key(&spine, root, result_keys + level, + level == info->levels - 1 ? NULL : &root); + if (r == -ENODATA) { + r = 0; + break; + + } else if (r) + break; + + count++; + } + exit_ro_spine(&spine); + + return r ? r : count; +} +EXPORT_SYMBOL_GPL(dm_btree_find_highest_key); diff --git a/drivers/md/persistent-data/dm-btree.h b/drivers/md/persistent-data/dm-btree.h new file mode 100644 index 00000000000..ae02c84410f --- /dev/null +++ b/drivers/md/persistent-data/dm-btree.h @@ -0,0 +1,145 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ +#ifndef _LINUX_DM_BTREE_H +#define _LINUX_DM_BTREE_H + +#include "dm-block-manager.h" + +struct dm_transaction_manager; + +/*----------------------------------------------------------------*/ + +/* + * Annotations used to check on-disk metadata is handled as little-endian. + */ +#ifdef __CHECKER__ +# define __dm_written_to_disk(x) __releases(x) +# define __dm_reads_from_disk(x) __acquires(x) +# define __dm_bless_for_disk(x) __acquire(x) +# define __dm_unbless_for_disk(x) __release(x) +#else +# define __dm_written_to_disk(x) +# define __dm_reads_from_disk(x) +# define __dm_bless_for_disk(x) +# define __dm_unbless_for_disk(x) +#endif + +/*----------------------------------------------------------------*/ + +/* + * Manipulates hierarchical B+ trees with 64-bit keys and arbitrary-sized + * values. + */ + +/* + * Infomation about the values stored within the btree. + */ +struct dm_btree_value_type { + void *context; + + /* + * The size in bytes of each value. + */ + uint32_t size; + + /* + * Any of these methods can be safely set to NULL if you do not + * need the corresponding feature. + */ + + /* + * The btree is making a duplicate of the value, for instance + * because previously-shared btree nodes have now diverged. + * @value argument is the new copy that the copy function may modify. + * (Probably it just wants to increment a reference count + * somewhere.) This method is _not_ called for insertion of a new + * value: It is assumed the ref count is already 1. + */ + void (*inc)(void *context, void *value); + + /* + * This value is being deleted. The btree takes care of freeing + * the memory pointed to by @value. Often the del function just + * needs to decrement a reference count somewhere. + */ + void (*dec)(void *context, void *value); + + /* + * A test for equality between two values. When a value is + * overwritten with a new one, the old one has the dec method + * called _unless_ the new and old value are deemed equal. + */ + int (*equal)(void *context, void *value1, void *value2); +}; + +/* + * The shape and contents of a btree. + */ +struct dm_btree_info { + struct dm_transaction_manager *tm; + + /* + * Number of nested btrees. (Not the depth of a single tree.) + */ + unsigned levels; + struct dm_btree_value_type value_type; +}; + +/* + * Set up an empty tree. O(1). + */ +int dm_btree_empty(struct dm_btree_info *info, dm_block_t *root); + +/* + * Delete a tree. O(n) - this is the slow one! It can also block, so + * please don't call it on an IO path. + */ +int dm_btree_del(struct dm_btree_info *info, dm_block_t root); + +/* + * All the lookup functions return -ENODATA if the key cannot be found. + */ + +/* + * Tries to find a key that matches exactly. O(ln(n)) + */ +int dm_btree_lookup(struct dm_btree_info *info, dm_block_t root, + uint64_t *keys, void *value_le); + +/* + * Insertion (or overwrite an existing value). O(ln(n)) + */ +int dm_btree_insert(struct dm_btree_info *info, dm_block_t root, + uint64_t *keys, void *value, dm_block_t *new_root) + __dm_written_to_disk(value); + +/* + * A variant of insert that indicates whether it actually inserted or just + * overwrote. Useful if you're keeping track of the number of entries in a + * tree. + */ +int dm_btree_insert_notify(struct dm_btree_info *info, dm_block_t root, + uint64_t *keys, void *value, dm_block_t *new_root, + int *inserted) + __dm_written_to_disk(value); + +/* + * Remove a key if present. This doesn't remove empty sub trees. Normally + * subtrees represent a separate entity, like a snapshot map, so this is + * correct behaviour. O(ln(n)). + */ +int dm_btree_remove(struct dm_btree_info *info, dm_block_t root, + uint64_t *keys, dm_block_t *new_root); + +/* + * Returns < 0 on failure. Otherwise the number of key entries that have + * been filled out. Remember trees can have zero entries, and as such have + * no highest key. + */ +int dm_btree_find_highest_key(struct dm_btree_info *info, dm_block_t root, + uint64_t *result_keys); + +#endif /* _LINUX_DM_BTREE_H */ diff --git a/drivers/md/persistent-data/dm-persistent-data-internal.h b/drivers/md/persistent-data/dm-persistent-data-internal.h new file mode 100644 index 00000000000..c49e26fff36 --- /dev/null +++ b/drivers/md/persistent-data/dm-persistent-data-internal.h @@ -0,0 +1,19 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#ifndef _DM_PERSISTENT_DATA_INTERNAL_H +#define _DM_PERSISTENT_DATA_INTERNAL_H + +#include "dm-block-manager.h" + +static inline unsigned dm_hash_block(dm_block_t b, unsigned hash_mask) +{ + const unsigned BIG_PRIME = 4294967291UL; + + return (((unsigned) b) * BIG_PRIME) & hash_mask; +} + +#endif /* _PERSISTENT_DATA_INTERNAL_H */ diff --git a/drivers/md/persistent-data/dm-space-map-checker.c b/drivers/md/persistent-data/dm-space-map-checker.c new file mode 100644 index 00000000000..bb44a937fe6 --- /dev/null +++ b/drivers/md/persistent-data/dm-space-map-checker.c @@ -0,0 +1,437 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#include "dm-space-map-checker.h" + +#include <linux/device-mapper.h> + +#ifdef CONFIG_DM_DEBUG_SPACE_MAPS + +#define DM_MSG_PREFIX "space map checker" + +/*----------------------------------------------------------------*/ + +struct count_array { + dm_block_t nr; + dm_block_t nr_free; + + uint32_t *counts; +}; + +static int ca_get_count(struct count_array *ca, dm_block_t b, uint32_t *count) +{ + if (b >= ca->nr) + return -EINVAL; + + *count = ca->counts[b]; + return 0; +} + +static int ca_count_more_than_one(struct count_array *ca, dm_block_t b, int *r) +{ + if (b >= ca->nr) + return -EINVAL; + + *r = ca->counts[b] > 1; + return 0; +} + +static int ca_set_count(struct count_array *ca, dm_block_t b, uint32_t count) +{ + uint32_t old_count; + + if (b >= ca->nr) + return -EINVAL; + + old_count = ca->counts[b]; + + if (!count && old_count) + ca->nr_free++; + + else if (count && !old_count) + ca->nr_free--; + + ca->counts[b] = count; + return 0; +} + +static int ca_inc_block(struct count_array *ca, dm_block_t b) +{ + if (b >= ca->nr) + return -EINVAL; + + ca_set_count(ca, b, ca->counts[b] + 1); + return 0; +} + +static int ca_dec_block(struct count_array *ca, dm_block_t b) +{ + if (b >= ca->nr) + return -EINVAL; + + BUG_ON(ca->counts[b] == 0); + ca_set_count(ca, b, ca->counts[b] - 1); + return 0; +} + +static int ca_create(struct count_array *ca, struct dm_space_map *sm) +{ + int r; + dm_block_t nr_blocks; + + r = dm_sm_get_nr_blocks(sm, &nr_blocks); + if (r) + return r; + + ca->nr = nr_blocks; + ca->nr_free = nr_blocks; + ca->counts = kzalloc(sizeof(*ca->counts) * nr_blocks, GFP_KERNEL); + if (!ca->counts) + return -ENOMEM; + + return 0; +} + +static int ca_load(struct count_array *ca, struct dm_space_map *sm) +{ + int r; + uint32_t count; + dm_block_t nr_blocks, i; + + r = dm_sm_get_nr_blocks(sm, &nr_blocks); + if (r) + return r; + + BUG_ON(ca->nr != nr_blocks); + + DMWARN("Loading debug space map from disk. This may take some time"); + for (i = 0; i < nr_blocks; i++) { + r = dm_sm_get_count(sm, i, &count); + if (r) { + DMERR("load failed"); + return r; + } + + ca_set_count(ca, i, count); + } + DMWARN("Load complete"); + + return 0; +} + +static int ca_extend(struct count_array *ca, dm_block_t extra_blocks) +{ + dm_block_t nr_blocks = ca->nr + extra_blocks; + uint32_t *counts = kzalloc(sizeof(*counts) * nr_blocks, GFP_KERNEL); + if (!counts) + return -ENOMEM; + + memcpy(counts, ca->counts, sizeof(*counts) * ca->nr); + kfree(ca->counts); + ca->nr = nr_blocks; + ca->nr_free += extra_blocks; + ca->counts = counts; + return 0; +} + +static int ca_commit(struct count_array *old, struct count_array *new) +{ + if (old->nr != new->nr) { + BUG_ON(old->nr > new->nr); + ca_extend(old, new->nr - old->nr); + } + + BUG_ON(old->nr != new->nr); + old->nr_free = new->nr_free; + memcpy(old->counts, new->counts, sizeof(*old->counts) * old->nr); + return 0; +} + +static void ca_destroy(struct count_array *ca) +{ + kfree(ca->counts); +} + +/*----------------------------------------------------------------*/ + +struct sm_checker { + struct dm_space_map sm; + + struct count_array old_counts; + struct count_array counts; + + struct dm_space_map *real_sm; +}; + +static void sm_checker_destroy(struct dm_space_map *sm) +{ + struct sm_checker *smc = container_of(sm, struct sm_checker, sm); + + dm_sm_destroy(smc->real_sm); + ca_destroy(&smc->old_counts); + ca_destroy(&smc->counts); + kfree(smc); +} + +static int sm_checker_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count) +{ + struct sm_checker *smc = container_of(sm, struct sm_checker, sm); + int r = dm_sm_get_nr_blocks(smc->real_sm, count); + if (!r) + BUG_ON(smc->old_counts.nr != *count); + return r; +} + +static int sm_checker_get_nr_free(struct dm_space_map *sm, dm_block_t *count) +{ + struct sm_checker *smc = container_of(sm, struct sm_checker, sm); + int r = dm_sm_get_nr_free(smc->real_sm, count); + if (!r) { + /* + * Slow, but we know it's correct. + */ + dm_block_t b, n = 0; + for (b = 0; b < smc->old_counts.nr; b++) + if (smc->old_counts.counts[b] == 0 && + smc->counts.counts[b] == 0) + n++; + + if (n != *count) + DMERR("free block counts differ, checker %u, sm-disk:%u", + (unsigned) n, (unsigned) *count); + } + return r; +} + +static int sm_checker_new_block(struct dm_space_map *sm, dm_block_t *b) +{ + struct sm_checker *smc = container_of(sm, struct sm_checker, sm); + int r = dm_sm_new_block(smc->real_sm, b); + + if (!r) { + BUG_ON(*b >= smc->old_counts.nr); + BUG_ON(smc->old_counts.counts[*b] != 0); + BUG_ON(*b >= smc->counts.nr); + BUG_ON(smc->counts.counts[*b] != 0); + ca_set_count(&smc->counts, *b, 1); + } + + return r; +} + +static int sm_checker_inc_block(struct dm_space_map *sm, dm_block_t b) +{ + struct sm_checker *smc = container_of(sm, struct sm_checker, sm); + int r = dm_sm_inc_block(smc->real_sm, b); + int r2 = ca_inc_block(&smc->counts, b); + BUG_ON(r != r2); + return r; +} + +static int sm_checker_dec_block(struct dm_space_map *sm, dm_block_t b) +{ + struct sm_checker *smc = container_of(sm, struct sm_checker, sm); + int r = dm_sm_dec_block(smc->real_sm, b); + int r2 = ca_dec_block(&smc->counts, b); + BUG_ON(r != r2); + return r; +} + +static int sm_checker_get_count(struct dm_space_map *sm, dm_block_t b, uint32_t *result) +{ + struct sm_checker *smc = container_of(sm, struct sm_checker, sm); + uint32_t result2 = 0; + int r = dm_sm_get_count(smc->real_sm, b, result); + int r2 = ca_get_count(&smc->counts, b, &result2); + + BUG_ON(r != r2); + if (!r) + BUG_ON(*result != result2); + return r; +} + +static int sm_checker_count_more_than_one(struct dm_space_map *sm, dm_block_t b, int *result) +{ + struct sm_checker *smc = container_of(sm, struct sm_checker, sm); + int result2 = 0; + int r = dm_sm_count_is_more_than_one(smc->real_sm, b, result); + int r2 = ca_count_more_than_one(&smc->counts, b, &result2); + + BUG_ON(r != r2); + if (!r) + BUG_ON(!(*result) && result2); + return r; +} + +static int sm_checker_set_count(struct dm_space_map *sm, dm_block_t b, uint32_t count) +{ + struct sm_checker *smc = container_of(sm, struct sm_checker, sm); + uint32_t old_rc; + int r = dm_sm_set_count(smc->real_sm, b, count); + int r2; + + BUG_ON(b >= smc->counts.nr); + old_rc = smc->counts.counts[b]; + r2 = ca_set_count(&smc->counts, b, count); + BUG_ON(r != r2); + + return r; +} + +static int sm_checker_commit(struct dm_space_map *sm) +{ + struct sm_checker *smc = container_of(sm, struct sm_checker, sm); + int r; + + r = dm_sm_commit(smc->real_sm); + if (r) + return r; + + r = ca_commit(&smc->old_counts, &smc->counts); + if (r) + return r; + + return 0; +} + +static int sm_checker_extend(struct dm_space_map *sm, dm_block_t extra_blocks) +{ + struct sm_checker *smc = container_of(sm, struct sm_checker, sm); + int r = dm_sm_extend(smc->real_sm, extra_blocks); + if (r) + return r; + + return ca_extend(&smc->counts, extra_blocks); +} + +static int sm_checker_root_size(struct dm_space_map *sm, size_t *result) +{ + struct sm_checker *smc = container_of(sm, struct sm_checker, sm); + return dm_sm_root_size(smc->real_sm, result); +} + +static int sm_checker_copy_root(struct dm_space_map *sm, void *copy_to_here_le, size_t len) +{ + struct sm_checker *smc = container_of(sm, struct sm_checker, sm); + return dm_sm_copy_root(smc->real_sm, copy_to_here_le, len); +} + +/*----------------------------------------------------------------*/ + +static struct dm_space_map ops_ = { + .destroy = sm_checker_destroy, + .get_nr_blocks = sm_checker_get_nr_blocks, + .get_nr_free = sm_checker_get_nr_free, + .inc_block = sm_checker_inc_block, + .dec_block = sm_checker_dec_block, + .new_block = sm_checker_new_block, + .get_count = sm_checker_get_count, + .count_is_more_than_one = sm_checker_count_more_than_one, + .set_count = sm_checker_set_count, + .commit = sm_checker_commit, + .extend = sm_checker_extend, + .root_size = sm_checker_root_size, + .copy_root = sm_checker_copy_root +}; + +struct dm_space_map *dm_sm_checker_create(struct dm_space_map *sm) +{ + int r; + struct sm_checker *smc; + + if (!sm) + return NULL; + + smc = kmalloc(sizeof(*smc), GFP_KERNEL); + if (!smc) + return NULL; + + memcpy(&smc->sm, &ops_, sizeof(smc->sm)); + r = ca_create(&smc->old_counts, sm); + if (r) { + kfree(smc); + return NULL; + } + + r = ca_create(&smc->counts, sm); + if (r) { + ca_destroy(&smc->old_counts); + kfree(smc); + return NULL; + } + + smc->real_sm = sm; + + r = ca_load(&smc->counts, sm); + if (r) { + ca_destroy(&smc->counts); + ca_destroy(&smc->old_counts); + kfree(smc); + return NULL; + } + + r = ca_commit(&smc->old_counts, &smc->counts); + if (r) { + ca_destroy(&smc->counts); + ca_destroy(&smc->old_counts); + kfree(smc); + return NULL; + } + + return &smc->sm; +} +EXPORT_SYMBOL_GPL(dm_sm_checker_create); + +struct dm_space_map *dm_sm_checker_create_fresh(struct dm_space_map *sm) +{ + int r; + struct sm_checker *smc; + + if (!sm) + return NULL; + + smc = kmalloc(sizeof(*smc), GFP_KERNEL); + if (!smc) + return NULL; + + memcpy(&smc->sm, &ops_, sizeof(smc->sm)); + r = ca_create(&smc->old_counts, sm); + if (r) { + kfree(smc); + return NULL; + } + + r = ca_create(&smc->counts, sm); + if (r) { + ca_destroy(&smc->old_counts); + kfree(smc); + return NULL; + } + + smc->real_sm = sm; + return &smc->sm; +} +EXPORT_SYMBOL_GPL(dm_sm_checker_create_fresh); + +/*----------------------------------------------------------------*/ + +#else + +struct dm_space_map *dm_sm_checker_create(struct dm_space_map *sm) +{ + return sm; +} +EXPORT_SYMBOL_GPL(dm_sm_checker_create); + +struct dm_space_map *dm_sm_checker_create_fresh(struct dm_space_map *sm) +{ + return sm; +} +EXPORT_SYMBOL_GPL(dm_sm_checker_create_fresh); + +/*----------------------------------------------------------------*/ + +#endif diff --git a/drivers/md/persistent-data/dm-space-map-checker.h b/drivers/md/persistent-data/dm-space-map-checker.h new file mode 100644 index 00000000000..444dccf6688 --- /dev/null +++ b/drivers/md/persistent-data/dm-space-map-checker.h @@ -0,0 +1,26 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#ifndef SNAPSHOTS_SPACE_MAP_CHECKER_H +#define SNAPSHOTS_SPACE_MAP_CHECKER_H + +#include "dm-space-map.h" + +/*----------------------------------------------------------------*/ + +/* + * This space map wraps a real on-disk space map, and verifies all of its + * operations. It uses a lot of memory, so only use if you have a specific + * problem that you're debugging. + * + * Ownership of @sm passes. + */ +struct dm_space_map *dm_sm_checker_create(struct dm_space_map *sm); +struct dm_space_map *dm_sm_checker_create_fresh(struct dm_space_map *sm); + +/*----------------------------------------------------------------*/ + +#endif diff --git a/drivers/md/persistent-data/dm-space-map-common.c b/drivers/md/persistent-data/dm-space-map-common.c new file mode 100644 index 00000000000..df2494c06cd --- /dev/null +++ b/drivers/md/persistent-data/dm-space-map-common.c @@ -0,0 +1,705 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#include "dm-space-map-common.h" +#include "dm-transaction-manager.h" + +#include <linux/bitops.h> +#include <linux/device-mapper.h> + +#define DM_MSG_PREFIX "space map common" + +/*----------------------------------------------------------------*/ + +/* + * Index validator. + */ +#define INDEX_CSUM_XOR 160478 + +static void index_prepare_for_write(struct dm_block_validator *v, + struct dm_block *b, + size_t block_size) +{ + struct disk_metadata_index *mi_le = dm_block_data(b); + + mi_le->blocknr = cpu_to_le64(dm_block_location(b)); + mi_le->csum = cpu_to_le32(dm_bm_checksum(&mi_le->padding, + block_size - sizeof(__le32), + INDEX_CSUM_XOR)); +} + +static int index_check(struct dm_block_validator *v, + struct dm_block *b, + size_t block_size) +{ + struct disk_metadata_index *mi_le = dm_block_data(b); + __le32 csum_disk; + + if (dm_block_location(b) != le64_to_cpu(mi_le->blocknr)) { + DMERR("index_check failed blocknr %llu wanted %llu", + le64_to_cpu(mi_le->blocknr), dm_block_location(b)); + return -ENOTBLK; + } + + csum_disk = cpu_to_le32(dm_bm_checksum(&mi_le->padding, + block_size - sizeof(__le32), + INDEX_CSUM_XOR)); + if (csum_disk != mi_le->csum) { + DMERR("index_check failed csum %u wanted %u", + le32_to_cpu(csum_disk), le32_to_cpu(mi_le->csum)); + return -EILSEQ; + } + + return 0; +} + +static struct dm_block_validator index_validator = { + .name = "index", + .prepare_for_write = index_prepare_for_write, + .check = index_check +}; + +/*----------------------------------------------------------------*/ + +/* + * Bitmap validator + */ +#define BITMAP_CSUM_XOR 240779 + +static void bitmap_prepare_for_write(struct dm_block_validator *v, + struct dm_block *b, + size_t block_size) +{ + struct disk_bitmap_header *disk_header = dm_block_data(b); + + disk_header->blocknr = cpu_to_le64(dm_block_location(b)); + disk_header->csum = cpu_to_le32(dm_bm_checksum(&disk_header->not_used, + block_size - sizeof(__le32), + BITMAP_CSUM_XOR)); +} + +static int bitmap_check(struct dm_block_validator *v, + struct dm_block *b, + size_t block_size) +{ + struct disk_bitmap_header *disk_header = dm_block_data(b); + __le32 csum_disk; + + if (dm_block_location(b) != le64_to_cpu(disk_header->blocknr)) { + DMERR("bitmap check failed blocknr %llu wanted %llu", + le64_to_cpu(disk_header->blocknr), dm_block_location(b)); + return -ENOTBLK; + } + + csum_disk = cpu_to_le32(dm_bm_checksum(&disk_header->not_used, + block_size - sizeof(__le32), + BITMAP_CSUM_XOR)); + if (csum_disk != disk_header->csum) { + DMERR("bitmap check failed csum %u wanted %u", + le32_to_cpu(csum_disk), le32_to_cpu(disk_header->csum)); + return -EILSEQ; + } + + return 0; +} + +static struct dm_block_validator dm_sm_bitmap_validator = { + .name = "sm_bitmap", + .prepare_for_write = bitmap_prepare_for_write, + .check = bitmap_check +}; + +/*----------------------------------------------------------------*/ + +#define ENTRIES_PER_WORD 32 +#define ENTRIES_SHIFT 5 + +static void *dm_bitmap_data(struct dm_block *b) +{ + return dm_block_data(b) + sizeof(struct disk_bitmap_header); +} + +#define WORD_MASK_HIGH 0xAAAAAAAAAAAAAAAAULL + +static unsigned bitmap_word_used(void *addr, unsigned b) +{ + __le64 *words_le = addr; + __le64 *w_le = words_le + (b >> ENTRIES_SHIFT); + + uint64_t bits = le64_to_cpu(*w_le); + uint64_t mask = (bits + WORD_MASK_HIGH + 1) & WORD_MASK_HIGH; + + return !(~bits & mask); +} + +static unsigned sm_lookup_bitmap(void *addr, unsigned b) +{ + __le64 *words_le = addr; + __le64 *w_le = words_le + (b >> ENTRIES_SHIFT); + unsigned hi, lo; + + b = (b & (ENTRIES_PER_WORD - 1)) << 1; + hi = !!test_bit_le(b, (void *) w_le); + lo = !!test_bit_le(b + 1, (void *) w_le); + return (hi << 1) | lo; +} + +static void sm_set_bitmap(void *addr, unsigned b, unsigned val) +{ + __le64 *words_le = addr; + __le64 *w_le = words_le + (b >> ENTRIES_SHIFT); + + b = (b & (ENTRIES_PER_WORD - 1)) << 1; + + if (val & 2) + __set_bit_le(b, (void *) w_le); + else + __clear_bit_le(b, (void *) w_le); + + if (val & 1) + __set_bit_le(b + 1, (void *) w_le); + else + __clear_bit_le(b + 1, (void *) w_le); +} + +static int sm_find_free(void *addr, unsigned begin, unsigned end, + unsigned *result) +{ + while (begin < end) { + if (!(begin & (ENTRIES_PER_WORD - 1)) && + bitmap_word_used(addr, begin)) { + begin += ENTRIES_PER_WORD; + continue; + } + + if (!sm_lookup_bitmap(addr, begin)) { + *result = begin; + return 0; + } + + begin++; + } + + return -ENOSPC; +} + +/*----------------------------------------------------------------*/ + +static int sm_ll_init(struct ll_disk *ll, struct dm_transaction_manager *tm) +{ + ll->tm = tm; + + ll->bitmap_info.tm = tm; + ll->bitmap_info.levels = 1; + + /* + * Because the new bitmap blocks are created via a shadow + * operation, the old entry has already had its reference count + * decremented and we don't need the btree to do any bookkeeping. + */ + ll->bitmap_info.value_type.size = sizeof(struct disk_index_entry); + ll->bitmap_info.value_type.inc = NULL; + ll->bitmap_info.value_type.dec = NULL; + ll->bitmap_info.value_type.equal = NULL; + + ll->ref_count_info.tm = tm; + ll->ref_count_info.levels = 1; + ll->ref_count_info.value_type.size = sizeof(uint32_t); + ll->ref_count_info.value_type.inc = NULL; + ll->ref_count_info.value_type.dec = NULL; + ll->ref_count_info.value_type.equal = NULL; + + ll->block_size = dm_bm_block_size(dm_tm_get_bm(tm)); + + if (ll->block_size > (1 << 30)) { + DMERR("block size too big to hold bitmaps"); + return -EINVAL; + } + + ll->entries_per_block = (ll->block_size - sizeof(struct disk_bitmap_header)) * + ENTRIES_PER_BYTE; + ll->nr_blocks = 0; + ll->bitmap_root = 0; + ll->ref_count_root = 0; + + return 0; +} + +int sm_ll_extend(struct ll_disk *ll, dm_block_t extra_blocks) +{ + int r; + dm_block_t i, nr_blocks, nr_indexes; + unsigned old_blocks, blocks; + + nr_blocks = ll->nr_blocks + extra_blocks; + old_blocks = dm_sector_div_up(ll->nr_blocks, ll->entries_per_block); + blocks = dm_sector_div_up(nr_blocks, ll->entries_per_block); + + nr_indexes = dm_sector_div_up(nr_blocks, ll->entries_per_block); + if (nr_indexes > ll->max_entries(ll)) { + DMERR("space map too large"); + return -EINVAL; + } + + for (i = old_blocks; i < blocks; i++) { + struct dm_block *b; + struct disk_index_entry idx; + + r = dm_tm_new_block(ll->tm, &dm_sm_bitmap_validator, &b); + if (r < 0) + return r; + idx.blocknr = cpu_to_le64(dm_block_location(b)); + + r = dm_tm_unlock(ll->tm, b); + if (r < 0) + return r; + + idx.nr_free = cpu_to_le32(ll->entries_per_block); + idx.none_free_before = 0; + + r = ll->save_ie(ll, i, &idx); + if (r < 0) + return r; + } + + ll->nr_blocks = nr_blocks; + return 0; +} + +int sm_ll_lookup_bitmap(struct ll_disk *ll, dm_block_t b, uint32_t *result) +{ + int r; + dm_block_t index = b; + struct disk_index_entry ie_disk; + struct dm_block *blk; + + b = do_div(index, ll->entries_per_block); + r = ll->load_ie(ll, index, &ie_disk); + if (r < 0) + return r; + + r = dm_tm_read_lock(ll->tm, le64_to_cpu(ie_disk.blocknr), + &dm_sm_bitmap_validator, &blk); + if (r < 0) + return r; + + *result = sm_lookup_bitmap(dm_bitmap_data(blk), b); + + return dm_tm_unlock(ll->tm, blk); +} + +int sm_ll_lookup(struct ll_disk *ll, dm_block_t b, uint32_t *result) +{ + __le32 le_rc; + int r = sm_ll_lookup_bitmap(ll, b, result); + + if (r) + return r; + + if (*result != 3) + return r; + + r = dm_btree_lookup(&ll->ref_count_info, ll->ref_count_root, &b, &le_rc); + if (r < 0) + return r; + + *result = le32_to_cpu(le_rc); + + return r; +} + +int sm_ll_find_free_block(struct ll_disk *ll, dm_block_t begin, + dm_block_t end, dm_block_t *result) +{ + int r; + struct disk_index_entry ie_disk; + dm_block_t i, index_begin = begin; + dm_block_t index_end = dm_sector_div_up(end, ll->entries_per_block); + + /* + * FIXME: Use shifts + */ + begin = do_div(index_begin, ll->entries_per_block); + end = do_div(end, ll->entries_per_block); + + for (i = index_begin; i < index_end; i++, begin = 0) { + struct dm_block *blk; + unsigned position; + uint32_t bit_end; + + r = ll->load_ie(ll, i, &ie_disk); + if (r < 0) + return r; + + if (le32_to_cpu(ie_disk.nr_free) == 0) + continue; + + r = dm_tm_read_lock(ll->tm, le64_to_cpu(ie_disk.blocknr), + &dm_sm_bitmap_validator, &blk); + if (r < 0) + return r; + + bit_end = (i == index_end - 1) ? end : ll->entries_per_block; + + r = sm_find_free(dm_bitmap_data(blk), + max_t(unsigned, begin, le32_to_cpu(ie_disk.none_free_before)), + bit_end, &position); + if (r == -ENOSPC) { + /* + * This might happen because we started searching + * part way through the bitmap. + */ + dm_tm_unlock(ll->tm, blk); + continue; + + } else if (r < 0) { + dm_tm_unlock(ll->tm, blk); + return r; + } + + r = dm_tm_unlock(ll->tm, blk); + if (r < 0) + return r; + + *result = i * ll->entries_per_block + (dm_block_t) position; + return 0; + } + + return -ENOSPC; +} + +int sm_ll_insert(struct ll_disk *ll, dm_block_t b, + uint32_t ref_count, enum allocation_event *ev) +{ + int r; + uint32_t bit, old; + struct dm_block *nb; + dm_block_t index = b; + struct disk_index_entry ie_disk; + void *bm_le; + int inc; + + bit = do_div(index, ll->entries_per_block); + r = ll->load_ie(ll, index, &ie_disk); + if (r < 0) + return r; + + r = dm_tm_shadow_block(ll->tm, le64_to_cpu(ie_disk.blocknr), + &dm_sm_bitmap_validator, &nb, &inc); + if (r < 0) { + DMERR("dm_tm_shadow_block() failed"); + return r; + } + ie_disk.blocknr = cpu_to_le64(dm_block_location(nb)); + + bm_le = dm_bitmap_data(nb); + old = sm_lookup_bitmap(bm_le, bit); + + if (ref_count <= 2) { + sm_set_bitmap(bm_le, bit, ref_count); + + r = dm_tm_unlock(ll->tm, nb); + if (r < 0) + return r; + +#if 0 + /* FIXME: dm_btree_remove doesn't handle this yet */ + if (old > 2) { + r = dm_btree_remove(&ll->ref_count_info, + ll->ref_count_root, + &b, &ll->ref_count_root); + if (r) + return r; + } +#endif + + } else { + __le32 le_rc = cpu_to_le32(ref_count); + + sm_set_bitmap(bm_le, bit, 3); + r = dm_tm_unlock(ll->tm, nb); + if (r < 0) + return r; + + __dm_bless_for_disk(&le_rc); + r = dm_btree_insert(&ll->ref_count_info, ll->ref_count_root, + &b, &le_rc, &ll->ref_count_root); + if (r < 0) { + DMERR("ref count insert failed"); + return r; + } + } + + if (ref_count && !old) { + *ev = SM_ALLOC; + ll->nr_allocated++; + ie_disk.nr_free = cpu_to_le32(le32_to_cpu(ie_disk.nr_free) - 1); + if (le32_to_cpu(ie_disk.none_free_before) == bit) + ie_disk.none_free_before = cpu_to_le32(bit + 1); + + } else if (old && !ref_count) { + *ev = SM_FREE; + ll->nr_allocated--; + ie_disk.nr_free = cpu_to_le32(le32_to_cpu(ie_disk.nr_free) + 1); + ie_disk.none_free_before = cpu_to_le32(min(le32_to_cpu(ie_disk.none_free_before), bit)); + } + + return ll->save_ie(ll, index, &ie_disk); +} + +int sm_ll_inc(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev) +{ + int r; + uint32_t rc; + + r = sm_ll_lookup(ll, b, &rc); + if (r) + return r; + + return sm_ll_insert(ll, b, rc + 1, ev); +} + +int sm_ll_dec(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev) +{ + int r; + uint32_t rc; + + r = sm_ll_lookup(ll, b, &rc); + if (r) + return r; + + if (!rc) + return -EINVAL; + + return sm_ll_insert(ll, b, rc - 1, ev); +} + +int sm_ll_commit(struct ll_disk *ll) +{ + return ll->commit(ll); +} + +/*----------------------------------------------------------------*/ + +static int metadata_ll_load_ie(struct ll_disk *ll, dm_block_t index, + struct disk_index_entry *ie) +{ + memcpy(ie, ll->mi_le.index + index, sizeof(*ie)); + return 0; +} + +static int metadata_ll_save_ie(struct ll_disk *ll, dm_block_t index, + struct disk_index_entry *ie) +{ + memcpy(ll->mi_le.index + index, ie, sizeof(*ie)); + return 0; +} + +static int metadata_ll_init_index(struct ll_disk *ll) +{ + int r; + struct dm_block *b; + + r = dm_tm_new_block(ll->tm, &index_validator, &b); + if (r < 0) + return r; + + memcpy(dm_block_data(b), &ll->mi_le, sizeof(ll->mi_le)); + ll->bitmap_root = dm_block_location(b); + + return dm_tm_unlock(ll->tm, b); +} + +static int metadata_ll_open(struct ll_disk *ll) +{ + int r; + struct dm_block *block; + + r = dm_tm_read_lock(ll->tm, ll->bitmap_root, + &index_validator, &block); + if (r) + return r; + + memcpy(&ll->mi_le, dm_block_data(block), sizeof(ll->mi_le)); + return dm_tm_unlock(ll->tm, block); +} + +static dm_block_t metadata_ll_max_entries(struct ll_disk *ll) +{ + return MAX_METADATA_BITMAPS; +} + +static int metadata_ll_commit(struct ll_disk *ll) +{ + int r, inc; + struct dm_block *b; + + r = dm_tm_shadow_block(ll->tm, ll->bitmap_root, &index_validator, &b, &inc); + if (r) + return r; + + memcpy(dm_block_data(b), &ll->mi_le, sizeof(ll->mi_le)); + ll->bitmap_root = dm_block_location(b); + + return dm_tm_unlock(ll->tm, b); +} + +int sm_ll_new_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm) +{ + int r; + + r = sm_ll_init(ll, tm); + if (r < 0) + return r; + + ll->load_ie = metadata_ll_load_ie; + ll->save_ie = metadata_ll_save_ie; + ll->init_index = metadata_ll_init_index; + ll->open_index = metadata_ll_open; + ll->max_entries = metadata_ll_max_entries; + ll->commit = metadata_ll_commit; + + ll->nr_blocks = 0; + ll->nr_allocated = 0; + + r = ll->init_index(ll); + if (r < 0) + return r; + + r = dm_btree_empty(&ll->ref_count_info, &ll->ref_count_root); + if (r < 0) + return r; + + return 0; +} + +int sm_ll_open_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm, + void *root_le, size_t len) +{ + int r; + struct disk_sm_root *smr = root_le; + + if (len < sizeof(struct disk_sm_root)) { + DMERR("sm_metadata root too small"); + return -ENOMEM; + } + + r = sm_ll_init(ll, tm); + if (r < 0) + return r; + + ll->load_ie = metadata_ll_load_ie; + ll->save_ie = metadata_ll_save_ie; + ll->init_index = metadata_ll_init_index; + ll->open_index = metadata_ll_open; + ll->max_entries = metadata_ll_max_entries; + ll->commit = metadata_ll_commit; + + ll->nr_blocks = le64_to_cpu(smr->nr_blocks); + ll->nr_allocated = le64_to_cpu(smr->nr_allocated); + ll->bitmap_root = le64_to_cpu(smr->bitmap_root); + ll->ref_count_root = le64_to_cpu(smr->ref_count_root); + + return ll->open_index(ll); +} + +/*----------------------------------------------------------------*/ + +static int disk_ll_load_ie(struct ll_disk *ll, dm_block_t index, + struct disk_index_entry *ie) +{ + return dm_btree_lookup(&ll->bitmap_info, ll->bitmap_root, &index, ie); +} + +static int disk_ll_save_ie(struct ll_disk *ll, dm_block_t index, + struct disk_index_entry *ie) +{ + __dm_bless_for_disk(ie); + return dm_btree_insert(&ll->bitmap_info, ll->bitmap_root, + &index, ie, &ll->bitmap_root); +} + +static int disk_ll_init_index(struct ll_disk *ll) +{ + return dm_btree_empty(&ll->bitmap_info, &ll->bitmap_root); +} + +static int disk_ll_open(struct ll_disk *ll) +{ + /* nothing to do */ + return 0; +} + +static dm_block_t disk_ll_max_entries(struct ll_disk *ll) +{ + return -1ULL; +} + +static int disk_ll_commit(struct ll_disk *ll) +{ + return 0; +} + +int sm_ll_new_disk(struct ll_disk *ll, struct dm_transaction_manager *tm) +{ + int r; + + r = sm_ll_init(ll, tm); + if (r < 0) + return r; + + ll->load_ie = disk_ll_load_ie; + ll->save_ie = disk_ll_save_ie; + ll->init_index = disk_ll_init_index; + ll->open_index = disk_ll_open; + ll->max_entries = disk_ll_max_entries; + ll->commit = disk_ll_commit; + + ll->nr_blocks = 0; + ll->nr_allocated = 0; + + r = ll->init_index(ll); + if (r < 0) + return r; + + r = dm_btree_empty(&ll->ref_count_info, &ll->ref_count_root); + if (r < 0) + return r; + + return 0; +} + +int sm_ll_open_disk(struct ll_disk *ll, struct dm_transaction_manager *tm, + void *root_le, size_t len) +{ + int r; + struct disk_sm_root *smr = root_le; + + if (len < sizeof(struct disk_sm_root)) { + DMERR("sm_metadata root too small"); + return -ENOMEM; + } + + r = sm_ll_init(ll, tm); + if (r < 0) + return r; + + ll->load_ie = disk_ll_load_ie; + ll->save_ie = disk_ll_save_ie; + ll->init_index = disk_ll_init_index; + ll->open_index = disk_ll_open; + ll->max_entries = disk_ll_max_entries; + ll->commit = disk_ll_commit; + + ll->nr_blocks = le64_to_cpu(smr->nr_blocks); + ll->nr_allocated = le64_to_cpu(smr->nr_allocated); + ll->bitmap_root = le64_to_cpu(smr->bitmap_root); + ll->ref_count_root = le64_to_cpu(smr->ref_count_root); + + return ll->open_index(ll); +} + +/*----------------------------------------------------------------*/ diff --git a/drivers/md/persistent-data/dm-space-map-common.h b/drivers/md/persistent-data/dm-space-map-common.h new file mode 100644 index 00000000000..8f220821a9a --- /dev/null +++ b/drivers/md/persistent-data/dm-space-map-common.h @@ -0,0 +1,126 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#ifndef DM_SPACE_MAP_COMMON_H +#define DM_SPACE_MAP_COMMON_H + +#include "dm-btree.h" + +/*----------------------------------------------------------------*/ + +/* + * Low level disk format + * + * Bitmap btree + * ------------ + * + * Each value stored in the btree is an index_entry. This points to a + * block that is used as a bitmap. Within the bitmap hold 2 bits per + * entry, which represent UNUSED = 0, REF_COUNT = 1, REF_COUNT = 2 and + * REF_COUNT = many. + * + * Refcount btree + * -------------- + * + * Any entry that has a ref count higher than 2 gets entered in the ref + * count tree. The leaf values for this tree is the 32-bit ref count. + */ + +struct disk_index_entry { + __le64 blocknr; + __le32 nr_free; + __le32 none_free_before; +} __packed; + + +#define MAX_METADATA_BITMAPS 255 +struct disk_metadata_index { + __le32 csum; + __le32 padding; + __le64 blocknr; + + struct disk_index_entry index[MAX_METADATA_BITMAPS]; +} __packed; + +struct ll_disk; + +typedef int (*load_ie_fn)(struct ll_disk *ll, dm_block_t index, struct disk_index_entry *result); +typedef int (*save_ie_fn)(struct ll_disk *ll, dm_block_t index, struct disk_index_entry *ie); +typedef int (*init_index_fn)(struct ll_disk *ll); +typedef int (*open_index_fn)(struct ll_disk *ll); +typedef dm_block_t (*max_index_entries_fn)(struct ll_disk *ll); +typedef int (*commit_fn)(struct ll_disk *ll); + +struct ll_disk { + struct dm_transaction_manager *tm; + struct dm_btree_info bitmap_info; + struct dm_btree_info ref_count_info; + + uint32_t block_size; + uint32_t entries_per_block; + dm_block_t nr_blocks; + dm_block_t nr_allocated; + + /* + * bitmap_root may be a btree root or a simple index. + */ + dm_block_t bitmap_root; + + dm_block_t ref_count_root; + + struct disk_metadata_index mi_le; + load_ie_fn load_ie; + save_ie_fn save_ie; + init_index_fn init_index; + open_index_fn open_index; + max_index_entries_fn max_entries; + commit_fn commit; +}; + +struct disk_sm_root { + __le64 nr_blocks; + __le64 nr_allocated; + __le64 bitmap_root; + __le64 ref_count_root; +} __packed; + +#define ENTRIES_PER_BYTE 4 + +struct disk_bitmap_header { + __le32 csum; + __le32 not_used; + __le64 blocknr; +} __packed; + +enum allocation_event { + SM_NONE, + SM_ALLOC, + SM_FREE, +}; + +/*----------------------------------------------------------------*/ + +int sm_ll_extend(struct ll_disk *ll, dm_block_t extra_blocks); +int sm_ll_lookup_bitmap(struct ll_disk *ll, dm_block_t b, uint32_t *result); +int sm_ll_lookup(struct ll_disk *ll, dm_block_t b, uint32_t *result); +int sm_ll_find_free_block(struct ll_disk *ll, dm_block_t begin, + dm_block_t end, dm_block_t *result); +int sm_ll_insert(struct ll_disk *ll, dm_block_t b, uint32_t ref_count, enum allocation_event *ev); +int sm_ll_inc(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev); +int sm_ll_dec(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev); +int sm_ll_commit(struct ll_disk *ll); + +int sm_ll_new_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm); +int sm_ll_open_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm, + void *root_le, size_t len); + +int sm_ll_new_disk(struct ll_disk *ll, struct dm_transaction_manager *tm); +int sm_ll_open_disk(struct ll_disk *ll, struct dm_transaction_manager *tm, + void *root_le, size_t len); + +/*----------------------------------------------------------------*/ + +#endif /* DM_SPACE_MAP_COMMON_H */ diff --git a/drivers/md/persistent-data/dm-space-map-disk.c b/drivers/md/persistent-data/dm-space-map-disk.c new file mode 100644 index 00000000000..aeff7852cf7 --- /dev/null +++ b/drivers/md/persistent-data/dm-space-map-disk.c @@ -0,0 +1,335 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#include "dm-space-map-checker.h" +#include "dm-space-map-common.h" +#include "dm-space-map-disk.h" +#include "dm-space-map.h" +#include "dm-transaction-manager.h" + +#include <linux/list.h> +#include <linux/slab.h> +#include <linux/module.h> +#include <linux/device-mapper.h> + +#define DM_MSG_PREFIX "space map disk" + +/*----------------------------------------------------------------*/ + +/* + * Space map interface. + */ +struct sm_disk { + struct dm_space_map sm; + + struct ll_disk ll; + struct ll_disk old_ll; + + dm_block_t begin; + dm_block_t nr_allocated_this_transaction; +}; + +static void sm_disk_destroy(struct dm_space_map *sm) +{ + struct sm_disk *smd = container_of(sm, struct sm_disk, sm); + + kfree(smd); +} + +static int sm_disk_extend(struct dm_space_map *sm, dm_block_t extra_blocks) +{ + struct sm_disk *smd = container_of(sm, struct sm_disk, sm); + + return sm_ll_extend(&smd->ll, extra_blocks); +} + +static int sm_disk_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count) +{ + struct sm_disk *smd = container_of(sm, struct sm_disk, sm); + *count = smd->old_ll.nr_blocks; + + return 0; +} + +static int sm_disk_get_nr_free(struct dm_space_map *sm, dm_block_t *count) +{ + struct sm_disk *smd = container_of(sm, struct sm_disk, sm); + *count = (smd->old_ll.nr_blocks - smd->old_ll.nr_allocated) - smd->nr_allocated_this_transaction; + + return 0; +} + +static int sm_disk_get_count(struct dm_space_map *sm, dm_block_t b, + uint32_t *result) +{ + struct sm_disk *smd = container_of(sm, struct sm_disk, sm); + return sm_ll_lookup(&smd->ll, b, result); +} + +static int sm_disk_count_is_more_than_one(struct dm_space_map *sm, dm_block_t b, + int *result) +{ + int r; + uint32_t count; + + r = sm_disk_get_count(sm, b, &count); + if (r) + return r; + + return count > 1; +} + +static int sm_disk_set_count(struct dm_space_map *sm, dm_block_t b, + uint32_t count) +{ + int r; + uint32_t old_count; + enum allocation_event ev; + struct sm_disk *smd = container_of(sm, struct sm_disk, sm); + + r = sm_ll_insert(&smd->ll, b, count, &ev); + if (!r) { + switch (ev) { + case SM_NONE: + break; + + case SM_ALLOC: + /* + * This _must_ be free in the prior transaction + * otherwise we've lost atomicity. + */ + smd->nr_allocated_this_transaction++; + break; + + case SM_FREE: + /* + * It's only free if it's also free in the last + * transaction. + */ + r = sm_ll_lookup(&smd->old_ll, b, &old_count); + if (r) + return r; + + if (!old_count) + smd->nr_allocated_this_transaction--; + break; + } + } + + return r; +} + +static int sm_disk_inc_block(struct dm_space_map *sm, dm_block_t b) +{ + int r; + enum allocation_event ev; + struct sm_disk *smd = container_of(sm, struct sm_disk, sm); + + r = sm_ll_inc(&smd->ll, b, &ev); + if (!r && (ev == SM_ALLOC)) + /* + * This _must_ be free in the prior transaction + * otherwise we've lost atomicity. + */ + smd->nr_allocated_this_transaction++; + + return r; +} + +static int sm_disk_dec_block(struct dm_space_map *sm, dm_block_t b) +{ + int r; + uint32_t old_count; + enum allocation_event ev; + struct sm_disk *smd = container_of(sm, struct sm_disk, sm); + + r = sm_ll_dec(&smd->ll, b, &ev); + if (!r && (ev == SM_FREE)) { + /* + * It's only free if it's also free in the last + * transaction. + */ + r = sm_ll_lookup(&smd->old_ll, b, &old_count); + if (r) + return r; + + if (!old_count) + smd->nr_allocated_this_transaction--; + } + + return r; +} + +static int sm_disk_new_block(struct dm_space_map *sm, dm_block_t *b) +{ + int r; + enum allocation_event ev; + struct sm_disk *smd = container_of(sm, struct sm_disk, sm); + + /* FIXME: we should loop round a couple of times */ + r = sm_ll_find_free_block(&smd->old_ll, smd->begin, smd->old_ll.nr_blocks, b); + if (r) + return r; + + smd->begin = *b + 1; + r = sm_ll_inc(&smd->ll, *b, &ev); + if (!r) { + BUG_ON(ev != SM_ALLOC); + smd->nr_allocated_this_transaction++; + } + + return r; +} + +static int sm_disk_commit(struct dm_space_map *sm) +{ + int r; + dm_block_t nr_free; + struct sm_disk *smd = container_of(sm, struct sm_disk, sm); + + r = sm_disk_get_nr_free(sm, &nr_free); + if (r) + return r; + + r = sm_ll_commit(&smd->ll); + if (r) + return r; + + memcpy(&smd->old_ll, &smd->ll, sizeof(smd->old_ll)); + smd->begin = 0; + smd->nr_allocated_this_transaction = 0; + + r = sm_disk_get_nr_free(sm, &nr_free); + if (r) + return r; + + return 0; +} + +static int sm_disk_root_size(struct dm_space_map *sm, size_t *result) +{ + *result = sizeof(struct disk_sm_root); + + return 0; +} + +static int sm_disk_copy_root(struct dm_space_map *sm, void *where_le, size_t max) +{ + struct sm_disk *smd = container_of(sm, struct sm_disk, sm); + struct disk_sm_root root_le; + + root_le.nr_blocks = cpu_to_le64(smd->ll.nr_blocks); + root_le.nr_allocated = cpu_to_le64(smd->ll.nr_allocated); + root_le.bitmap_root = cpu_to_le64(smd->ll.bitmap_root); + root_le.ref_count_root = cpu_to_le64(smd->ll.ref_count_root); + + if (max < sizeof(root_le)) + return -ENOSPC; + + memcpy(where_le, &root_le, sizeof(root_le)); + + return 0; +} + +/*----------------------------------------------------------------*/ + +static struct dm_space_map ops = { + .destroy = sm_disk_destroy, + .extend = sm_disk_extend, + .get_nr_blocks = sm_disk_get_nr_blocks, + .get_nr_free = sm_disk_get_nr_free, + .get_count = sm_disk_get_count, + .count_is_more_than_one = sm_disk_count_is_more_than_one, + .set_count = sm_disk_set_count, + .inc_block = sm_disk_inc_block, + .dec_block = sm_disk_dec_block, + .new_block = sm_disk_new_block, + .commit = sm_disk_commit, + .root_size = sm_disk_root_size, + .copy_root = sm_disk_copy_root +}; + +static struct dm_space_map *dm_sm_disk_create_real( + struct dm_transaction_manager *tm, + dm_block_t nr_blocks) +{ + int r; + struct sm_disk *smd; + + smd = kmalloc(sizeof(*smd), GFP_KERNEL); + if (!smd) + return ERR_PTR(-ENOMEM); + + smd->begin = 0; + smd->nr_allocated_this_transaction = 0; + memcpy(&smd->sm, &ops, sizeof(smd->sm)); + + r = sm_ll_new_disk(&smd->ll, tm); + if (r) + goto bad; + + r = sm_ll_extend(&smd->ll, nr_blocks); + if (r) + goto bad; + + r = sm_disk_commit(&smd->sm); + if (r) + goto bad; + + return &smd->sm; + +bad: + kfree(smd); + return ERR_PTR(r); +} + +struct dm_space_map *dm_sm_disk_create(struct dm_transaction_manager *tm, + dm_block_t nr_blocks) +{ + struct dm_space_map *sm = dm_sm_disk_create_real(tm, nr_blocks); + return dm_sm_checker_create_fresh(sm); +} +EXPORT_SYMBOL_GPL(dm_sm_disk_create); + +static struct dm_space_map *dm_sm_disk_open_real( + struct dm_transaction_manager *tm, + void *root_le, size_t len) +{ + int r; + struct sm_disk *smd; + + smd = kmalloc(sizeof(*smd), GFP_KERNEL); + if (!smd) + return ERR_PTR(-ENOMEM); + + smd->begin = 0; + smd->nr_allocated_this_transaction = 0; + memcpy(&smd->sm, &ops, sizeof(smd->sm)); + + r = sm_ll_open_disk(&smd->ll, tm, root_le, len); + if (r) + goto bad; + + r = sm_disk_commit(&smd->sm); + if (r) + goto bad; + + return &smd->sm; + +bad: + kfree(smd); + return ERR_PTR(r); +} + +struct dm_space_map *dm_sm_disk_open(struct dm_transaction_manager *tm, + void *root_le, size_t len) +{ + return dm_sm_checker_create( + dm_sm_disk_open_real(tm, root_le, len)); +} +EXPORT_SYMBOL_GPL(dm_sm_disk_open); + +/*----------------------------------------------------------------*/ diff --git a/drivers/md/persistent-data/dm-space-map-disk.h b/drivers/md/persistent-data/dm-space-map-disk.h new file mode 100644 index 00000000000..447a0a9a2d9 --- /dev/null +++ b/drivers/md/persistent-data/dm-space-map-disk.h @@ -0,0 +1,25 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#ifndef _LINUX_DM_SPACE_MAP_DISK_H +#define _LINUX_DM_SPACE_MAP_DISK_H + +#include "dm-block-manager.h" + +struct dm_space_map; +struct dm_transaction_manager; + +/* + * Unfortunately we have to use two-phase construction due to the cycle + * between the tm and sm. + */ +struct dm_space_map *dm_sm_disk_create(struct dm_transaction_manager *tm, + dm_block_t nr_blocks); + +struct dm_space_map *dm_sm_disk_open(struct dm_transaction_manager *tm, + void *root, size_t len); + +#endif /* _LINUX_DM_SPACE_MAP_DISK_H */ diff --git a/drivers/md/persistent-data/dm-space-map-metadata.c b/drivers/md/persistent-data/dm-space-map-metadata.c new file mode 100644 index 00000000000..e89ae5e7a51 --- /dev/null +++ b/drivers/md/persistent-data/dm-space-map-metadata.c @@ -0,0 +1,596 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#include "dm-space-map.h" +#include "dm-space-map-common.h" +#include "dm-space-map-metadata.h" + +#include <linux/list.h> +#include <linux/slab.h> +#include <linux/device-mapper.h> + +#define DM_MSG_PREFIX "space map metadata" + +/*----------------------------------------------------------------*/ + +/* + * Space map interface. + * + * The low level disk format is written using the standard btree and + * transaction manager. This means that performing disk operations may + * cause us to recurse into the space map in order to allocate new blocks. + * For this reason we have a pool of pre-allocated blocks large enough to + * service any metadata_ll_disk operation. + */ + +/* + * FIXME: we should calculate this based on the size of the device. + * Only the metadata space map needs this functionality. + */ +#define MAX_RECURSIVE_ALLOCATIONS 1024 + +enum block_op_type { + BOP_INC, + BOP_DEC +}; + +struct block_op { + enum block_op_type type; + dm_block_t block; +}; + +struct sm_metadata { + struct dm_space_map sm; + + struct ll_disk ll; + struct ll_disk old_ll; + + dm_block_t begin; + + unsigned recursion_count; + unsigned allocated_this_transaction; + unsigned nr_uncommitted; + struct block_op uncommitted[MAX_RECURSIVE_ALLOCATIONS]; +}; + +static int add_bop(struct sm_metadata *smm, enum block_op_type type, dm_block_t b) +{ + struct block_op *op; + + if (smm->nr_uncommitted == MAX_RECURSIVE_ALLOCATIONS) { + DMERR("too many recursive allocations"); + return -ENOMEM; + } + + op = smm->uncommitted + smm->nr_uncommitted++; + op->type = type; + op->block = b; + + return 0; +} + +static int commit_bop(struct sm_metadata *smm, struct block_op *op) +{ + int r = 0; + enum allocation_event ev; + + switch (op->type) { + case BOP_INC: + r = sm_ll_inc(&smm->ll, op->block, &ev); + break; + + case BOP_DEC: + r = sm_ll_dec(&smm->ll, op->block, &ev); + break; + } + + return r; +} + +static void in(struct sm_metadata *smm) +{ + smm->recursion_count++; +} + +static int out(struct sm_metadata *smm) +{ + int r = 0; + + /* + * If we're not recursing then very bad things are happening. + */ + if (!smm->recursion_count) { + DMERR("lost track of recursion depth"); + return -ENOMEM; + } + + if (smm->recursion_count == 1 && smm->nr_uncommitted) { + while (smm->nr_uncommitted && !r) { + smm->nr_uncommitted--; + r = commit_bop(smm, smm->uncommitted + + smm->nr_uncommitted); + if (r) + break; + } + } + + smm->recursion_count--; + + return r; +} + +/* + * When using the out() function above, we often want to combine an error + * code for the operation run in the recursive context with that from + * out(). + */ +static int combine_errors(int r1, int r2) +{ + return r1 ? r1 : r2; +} + +static int recursing(struct sm_metadata *smm) +{ + return smm->recursion_count; +} + +static void sm_metadata_destroy(struct dm_space_map *sm) +{ + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + kfree(smm); +} + +static int sm_metadata_extend(struct dm_space_map *sm, dm_block_t extra_blocks) +{ + DMERR("doesn't support extend"); + return -EINVAL; +} + +static int sm_metadata_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count) +{ + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + *count = smm->ll.nr_blocks; + + return 0; +} + +static int sm_metadata_get_nr_free(struct dm_space_map *sm, dm_block_t *count) +{ + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + *count = smm->old_ll.nr_blocks - smm->old_ll.nr_allocated - + smm->allocated_this_transaction; + + return 0; +} + +static int sm_metadata_get_count(struct dm_space_map *sm, dm_block_t b, + uint32_t *result) +{ + int r, i; + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + unsigned adjustment = 0; + + /* + * We may have some uncommitted adjustments to add. This list + * should always be really short. + */ + for (i = 0; i < smm->nr_uncommitted; i++) { + struct block_op *op = smm->uncommitted + i; + + if (op->block != b) + continue; + + switch (op->type) { + case BOP_INC: + adjustment++; + break; + + case BOP_DEC: + adjustment--; + break; + } + } + + r = sm_ll_lookup(&smm->ll, b, result); + if (r) + return r; + + *result += adjustment; + + return 0; +} + +static int sm_metadata_count_is_more_than_one(struct dm_space_map *sm, + dm_block_t b, int *result) +{ + int r, i, adjustment = 0; + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + uint32_t rc; + + /* + * We may have some uncommitted adjustments to add. This list + * should always be really short. + */ + for (i = 0; i < smm->nr_uncommitted; i++) { + struct block_op *op = smm->uncommitted + i; + + if (op->block != b) + continue; + + switch (op->type) { + case BOP_INC: + adjustment++; + break; + + case BOP_DEC: + adjustment--; + break; + } + } + + if (adjustment > 1) { + *result = 1; + return 0; + } + + r = sm_ll_lookup_bitmap(&smm->ll, b, &rc); + if (r) + return r; + + if (rc == 3) + /* + * We err on the side of caution, and always return true. + */ + *result = 1; + else + *result = rc + adjustment > 1; + + return 0; +} + +static int sm_metadata_set_count(struct dm_space_map *sm, dm_block_t b, + uint32_t count) +{ + int r, r2; + enum allocation_event ev; + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + if (smm->recursion_count) { + DMERR("cannot recurse set_count()"); + return -EINVAL; + } + + in(smm); + r = sm_ll_insert(&smm->ll, b, count, &ev); + r2 = out(smm); + + return combine_errors(r, r2); +} + +static int sm_metadata_inc_block(struct dm_space_map *sm, dm_block_t b) +{ + int r, r2 = 0; + enum allocation_event ev; + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + if (recursing(smm)) + r = add_bop(smm, BOP_INC, b); + else { + in(smm); + r = sm_ll_inc(&smm->ll, b, &ev); + r2 = out(smm); + } + + return combine_errors(r, r2); +} + +static int sm_metadata_dec_block(struct dm_space_map *sm, dm_block_t b) +{ + int r, r2 = 0; + enum allocation_event ev; + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + if (recursing(smm)) + r = add_bop(smm, BOP_DEC, b); + else { + in(smm); + r = sm_ll_dec(&smm->ll, b, &ev); + r2 = out(smm); + } + + return combine_errors(r, r2); +} + +static int sm_metadata_new_block_(struct dm_space_map *sm, dm_block_t *b) +{ + int r, r2 = 0; + enum allocation_event ev; + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + r = sm_ll_find_free_block(&smm->old_ll, smm->begin, smm->old_ll.nr_blocks, b); + if (r) + return r; + + smm->begin = *b + 1; + + if (recursing(smm)) + r = add_bop(smm, BOP_INC, *b); + else { + in(smm); + r = sm_ll_inc(&smm->ll, *b, &ev); + r2 = out(smm); + } + + if (!r) + smm->allocated_this_transaction++; + + return combine_errors(r, r2); +} + +static int sm_metadata_new_block(struct dm_space_map *sm, dm_block_t *b) +{ + int r = sm_metadata_new_block_(sm, b); + if (r) + DMERR("out of metadata space"); + return r; +} + +static int sm_metadata_commit(struct dm_space_map *sm) +{ + int r; + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + r = sm_ll_commit(&smm->ll); + if (r) + return r; + + memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll)); + smm->begin = 0; + smm->allocated_this_transaction = 0; + + return 0; +} + +static int sm_metadata_root_size(struct dm_space_map *sm, size_t *result) +{ + *result = sizeof(struct disk_sm_root); + + return 0; +} + +static int sm_metadata_copy_root(struct dm_space_map *sm, void *where_le, size_t max) +{ + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + struct disk_sm_root root_le; + + root_le.nr_blocks = cpu_to_le64(smm->ll.nr_blocks); + root_le.nr_allocated = cpu_to_le64(smm->ll.nr_allocated); + root_le.bitmap_root = cpu_to_le64(smm->ll.bitmap_root); + root_le.ref_count_root = cpu_to_le64(smm->ll.ref_count_root); + + if (max < sizeof(root_le)) + return -ENOSPC; + + memcpy(where_le, &root_le, sizeof(root_le)); + + return 0; +} + +static struct dm_space_map ops = { + .destroy = sm_metadata_destroy, + .extend = sm_metadata_extend, + .get_nr_blocks = sm_metadata_get_nr_blocks, + .get_nr_free = sm_metadata_get_nr_free, + .get_count = sm_metadata_get_count, + .count_is_more_than_one = sm_metadata_count_is_more_than_one, + .set_count = sm_metadata_set_count, + .inc_block = sm_metadata_inc_block, + .dec_block = sm_metadata_dec_block, + .new_block = sm_metadata_new_block, + .commit = sm_metadata_commit, + .root_size = sm_metadata_root_size, + .copy_root = sm_metadata_copy_root +}; + +/*----------------------------------------------------------------*/ + +/* + * When a new space map is created that manages its own space. We use + * this tiny bootstrap allocator. + */ +static void sm_bootstrap_destroy(struct dm_space_map *sm) +{ +} + +static int sm_bootstrap_extend(struct dm_space_map *sm, dm_block_t extra_blocks) +{ + DMERR("boostrap doesn't support extend"); + + return -EINVAL; +} + +static int sm_bootstrap_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count) +{ + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + return smm->ll.nr_blocks; +} + +static int sm_bootstrap_get_nr_free(struct dm_space_map *sm, dm_block_t *count) +{ + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + *count = smm->ll.nr_blocks - smm->begin; + + return 0; +} + +static int sm_bootstrap_get_count(struct dm_space_map *sm, dm_block_t b, + uint32_t *result) +{ + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + return b < smm->begin ? 1 : 0; +} + +static int sm_bootstrap_count_is_more_than_one(struct dm_space_map *sm, + dm_block_t b, int *result) +{ + *result = 0; + + return 0; +} + +static int sm_bootstrap_set_count(struct dm_space_map *sm, dm_block_t b, + uint32_t count) +{ + DMERR("boostrap doesn't support set_count"); + + return -EINVAL; +} + +static int sm_bootstrap_new_block(struct dm_space_map *sm, dm_block_t *b) +{ + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + /* + * We know the entire device is unused. + */ + if (smm->begin == smm->ll.nr_blocks) + return -ENOSPC; + + *b = smm->begin++; + + return 0; +} + +static int sm_bootstrap_inc_block(struct dm_space_map *sm, dm_block_t b) +{ + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + return add_bop(smm, BOP_INC, b); +} + +static int sm_bootstrap_dec_block(struct dm_space_map *sm, dm_block_t b) +{ + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + return add_bop(smm, BOP_DEC, b); +} + +static int sm_bootstrap_commit(struct dm_space_map *sm) +{ + return 0; +} + +static int sm_bootstrap_root_size(struct dm_space_map *sm, size_t *result) +{ + DMERR("boostrap doesn't support root_size"); + + return -EINVAL; +} + +static int sm_bootstrap_copy_root(struct dm_space_map *sm, void *where, + size_t max) +{ + DMERR("boostrap doesn't support copy_root"); + + return -EINVAL; +} + +static struct dm_space_map bootstrap_ops = { + .destroy = sm_bootstrap_destroy, + .extend = sm_bootstrap_extend, + .get_nr_blocks = sm_bootstrap_get_nr_blocks, + .get_nr_free = sm_bootstrap_get_nr_free, + .get_count = sm_bootstrap_get_count, + .count_is_more_than_one = sm_bootstrap_count_is_more_than_one, + .set_count = sm_bootstrap_set_count, + .inc_block = sm_bootstrap_inc_block, + .dec_block = sm_bootstrap_dec_block, + .new_block = sm_bootstrap_new_block, + .commit = sm_bootstrap_commit, + .root_size = sm_bootstrap_root_size, + .copy_root = sm_bootstrap_copy_root +}; + +/*----------------------------------------------------------------*/ + +struct dm_space_map *dm_sm_metadata_init(void) +{ + struct sm_metadata *smm; + + smm = kmalloc(sizeof(*smm), GFP_KERNEL); + if (!smm) + return ERR_PTR(-ENOMEM); + + memcpy(&smm->sm, &ops, sizeof(smm->sm)); + + return &smm->sm; +} + +int dm_sm_metadata_create(struct dm_space_map *sm, + struct dm_transaction_manager *tm, + dm_block_t nr_blocks, + dm_block_t superblock) +{ + int r; + dm_block_t i; + enum allocation_event ev; + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + smm->begin = superblock + 1; + smm->recursion_count = 0; + smm->allocated_this_transaction = 0; + smm->nr_uncommitted = 0; + + memcpy(&smm->sm, &bootstrap_ops, sizeof(smm->sm)); + + r = sm_ll_new_metadata(&smm->ll, tm); + if (r) + return r; + + r = sm_ll_extend(&smm->ll, nr_blocks); + if (r) + return r; + + memcpy(&smm->sm, &ops, sizeof(smm->sm)); + + /* + * Now we need to update the newly created data structures with the + * allocated blocks that they were built from. + */ + for (i = superblock; !r && i < smm->begin; i++) + r = sm_ll_inc(&smm->ll, i, &ev); + + if (r) + return r; + + return sm_metadata_commit(sm); +} + +int dm_sm_metadata_open(struct dm_space_map *sm, + struct dm_transaction_manager *tm, + void *root_le, size_t len) +{ + int r; + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + r = sm_ll_open_metadata(&smm->ll, tm, root_le, len); + if (r) + return r; + + smm->begin = 0; + smm->recursion_count = 0; + smm->allocated_this_transaction = 0; + smm->nr_uncommitted = 0; + + memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll)); + return 0; +} diff --git a/drivers/md/persistent-data/dm-space-map-metadata.h b/drivers/md/persistent-data/dm-space-map-metadata.h new file mode 100644 index 00000000000..39bba0801cf --- /dev/null +++ b/drivers/md/persistent-data/dm-space-map-metadata.h @@ -0,0 +1,33 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#ifndef DM_SPACE_MAP_METADATA_H +#define DM_SPACE_MAP_METADATA_H + +#include "dm-transaction-manager.h" + +/* + * Unfortunately we have to use two-phase construction due to the cycle + * between the tm and sm. + */ +struct dm_space_map *dm_sm_metadata_init(void); + +/* + * Create a fresh space map. + */ +int dm_sm_metadata_create(struct dm_space_map *sm, + struct dm_transaction_manager *tm, + dm_block_t nr_blocks, + dm_block_t superblock); + +/* + * Open from a previously-recorded root. + */ +int dm_sm_metadata_open(struct dm_space_map *sm, + struct dm_transaction_manager *tm, + void *root_le, size_t len); + +#endif /* DM_SPACE_MAP_METADATA_H */ diff --git a/drivers/md/persistent-data/dm-space-map.h b/drivers/md/persistent-data/dm-space-map.h new file mode 100644 index 00000000000..1cbfc6b1638 --- /dev/null +++ b/drivers/md/persistent-data/dm-space-map.h @@ -0,0 +1,134 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#ifndef _LINUX_DM_SPACE_MAP_H +#define _LINUX_DM_SPACE_MAP_H + +#include "dm-block-manager.h" + +/* + * struct dm_space_map keeps a record of how many times each block in a device + * is referenced. It needs to be fixed on disk as part of the transaction. + */ +struct dm_space_map { + void (*destroy)(struct dm_space_map *sm); + + /* + * You must commit before allocating the newly added space. + */ + int (*extend)(struct dm_space_map *sm, dm_block_t extra_blocks); + + /* + * Extensions do not appear in this count until after commit has + * been called. + */ + int (*get_nr_blocks)(struct dm_space_map *sm, dm_block_t *count); + + /* + * Space maps must never allocate a block from the previous + * transaction, in case we need to rollback. This complicates the + * semantics of get_nr_free(), it should return the number of blocks + * that are available for allocation _now_. For instance you may + * have blocks with a zero reference count that will not be + * available for allocation until after the next commit. + */ + int (*get_nr_free)(struct dm_space_map *sm, dm_block_t *count); + + int (*get_count)(struct dm_space_map *sm, dm_block_t b, uint32_t *result); + int (*count_is_more_than_one)(struct dm_space_map *sm, dm_block_t b, + int *result); + int (*set_count)(struct dm_space_map *sm, dm_block_t b, uint32_t count); + + int (*commit)(struct dm_space_map *sm); + + int (*inc_block)(struct dm_space_map *sm, dm_block_t b); + int (*dec_block)(struct dm_space_map *sm, dm_block_t b); + + /* + * new_block will increment the returned block. + */ + int (*new_block)(struct dm_space_map *sm, dm_block_t *b); + + /* + * The root contains all the information needed to fix the space map. + * Generally this info is small, so squirrel it away in a disk block + * along with other info. + */ + int (*root_size)(struct dm_space_map *sm, size_t *result); + int (*copy_root)(struct dm_space_map *sm, void *copy_to_here_le, size_t len); +}; + +/*----------------------------------------------------------------*/ + +static inline void dm_sm_destroy(struct dm_space_map *sm) +{ + sm->destroy(sm); +} + +static inline int dm_sm_extend(struct dm_space_map *sm, dm_block_t extra_blocks) +{ + return sm->extend(sm, extra_blocks); +} + +static inline int dm_sm_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count) +{ + return sm->get_nr_blocks(sm, count); +} + +static inline int dm_sm_get_nr_free(struct dm_space_map *sm, dm_block_t *count) +{ + return sm->get_nr_free(sm, count); +} + +static inline int dm_sm_get_count(struct dm_space_map *sm, dm_block_t b, + uint32_t *result) +{ + return sm->get_count(sm, b, result); +} + +static inline int dm_sm_count_is_more_than_one(struct dm_space_map *sm, + dm_block_t b, int *result) +{ + return sm->count_is_more_than_one(sm, b, result); +} + +static inline int dm_sm_set_count(struct dm_space_map *sm, dm_block_t b, + uint32_t count) +{ + return sm->set_count(sm, b, count); +} + +static inline int dm_sm_commit(struct dm_space_map *sm) +{ + return sm->commit(sm); +} + +static inline int dm_sm_inc_block(struct dm_space_map *sm, dm_block_t b) +{ + return sm->inc_block(sm, b); +} + +static inline int dm_sm_dec_block(struct dm_space_map *sm, dm_block_t b) +{ + return sm->dec_block(sm, b); +} + +static inline int dm_sm_new_block(struct dm_space_map *sm, dm_block_t *b) +{ + return sm->new_block(sm, b); +} + +static inline int dm_sm_root_size(struct dm_space_map *sm, size_t *result) +{ + return sm->root_size(sm, result); +} + +static inline int dm_sm_copy_root(struct dm_space_map *sm, void *copy_to_here_le, size_t len) +{ + return sm->copy_root(sm, copy_to_here_le, len); +} + +#endif /* _LINUX_DM_SPACE_MAP_H */ diff --git a/drivers/md/persistent-data/dm-transaction-manager.c b/drivers/md/persistent-data/dm-transaction-manager.c new file mode 100644 index 00000000000..728e89a3f97 --- /dev/null +++ b/drivers/md/persistent-data/dm-transaction-manager.c @@ -0,0 +1,400 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ +#include "dm-transaction-manager.h" +#include "dm-space-map.h" +#include "dm-space-map-checker.h" +#include "dm-space-map-disk.h" +#include "dm-space-map-metadata.h" +#include "dm-persistent-data-internal.h" + +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/device-mapper.h> + +#define DM_MSG_PREFIX "transaction manager" + +/*----------------------------------------------------------------*/ + +struct shadow_info { + struct hlist_node hlist; + dm_block_t where; +}; + +/* + * It would be nice if we scaled with the size of transaction. + */ +#define HASH_SIZE 256 +#define HASH_MASK (HASH_SIZE - 1) + +struct dm_transaction_manager { + int is_clone; + struct dm_transaction_manager *real; + + struct dm_block_manager *bm; + struct dm_space_map *sm; + + spinlock_t lock; + struct hlist_head buckets[HASH_SIZE]; +}; + +/*----------------------------------------------------------------*/ + +static int is_shadow(struct dm_transaction_manager *tm, dm_block_t b) +{ + int r = 0; + unsigned bucket = dm_hash_block(b, HASH_MASK); + struct shadow_info *si; + struct hlist_node *n; + + spin_lock(&tm->lock); + hlist_for_each_entry(si, n, tm->buckets + bucket, hlist) + if (si->where == b) { + r = 1; + break; + } + spin_unlock(&tm->lock); + + return r; +} + +/* + * This can silently fail if there's no memory. We're ok with this since + * creating redundant shadows causes no harm. + */ +static void insert_shadow(struct dm_transaction_manager *tm, dm_block_t b) +{ + unsigned bucket; + struct shadow_info *si; + + si = kmalloc(sizeof(*si), GFP_NOIO); + if (si) { + si->where = b; + bucket = dm_hash_block(b, HASH_MASK); + spin_lock(&tm->lock); + hlist_add_head(&si->hlist, tm->buckets + bucket); + spin_unlock(&tm->lock); + } +} + +static void wipe_shadow_table(struct dm_transaction_manager *tm) +{ + struct shadow_info *si; + struct hlist_node *n, *tmp; + struct hlist_head *bucket; + int i; + + spin_lock(&tm->lock); + for (i = 0; i < HASH_SIZE; i++) { + bucket = tm->buckets + i; + hlist_for_each_entry_safe(si, n, tmp, bucket, hlist) + kfree(si); + + INIT_HLIST_HEAD(bucket); + } + + spin_unlock(&tm->lock); +} + +/*----------------------------------------------------------------*/ + +static struct dm_transaction_manager *dm_tm_create(struct dm_block_manager *bm, + struct dm_space_map *sm) +{ + int i; + struct dm_transaction_manager *tm; + + tm = kmalloc(sizeof(*tm), GFP_KERNEL); + if (!tm) + return ERR_PTR(-ENOMEM); + + tm->is_clone = 0; + tm->real = NULL; + tm->bm = bm; + tm->sm = sm; + + spin_lock_init(&tm->lock); + for (i = 0; i < HASH_SIZE; i++) + INIT_HLIST_HEAD(tm->buckets + i); + + return tm; +} + +struct dm_transaction_manager *dm_tm_create_non_blocking_clone(struct dm_transaction_manager *real) +{ + struct dm_transaction_manager *tm; + + tm = kmalloc(sizeof(*tm), GFP_KERNEL); + if (tm) { + tm->is_clone = 1; + tm->real = real; + } + + return tm; +} +EXPORT_SYMBOL_GPL(dm_tm_create_non_blocking_clone); + +void dm_tm_destroy(struct dm_transaction_manager *tm) +{ + kfree(tm); +} +EXPORT_SYMBOL_GPL(dm_tm_destroy); + +int dm_tm_pre_commit(struct dm_transaction_manager *tm) +{ + int r; + + if (tm->is_clone) + return -EWOULDBLOCK; + + r = dm_sm_commit(tm->sm); + if (r < 0) + return r; + + return 0; +} +EXPORT_SYMBOL_GPL(dm_tm_pre_commit); + +int dm_tm_commit(struct dm_transaction_manager *tm, struct dm_block *root) +{ + if (tm->is_clone) + return -EWOULDBLOCK; + + wipe_shadow_table(tm); + + return dm_bm_flush_and_unlock(tm->bm, root); +} +EXPORT_SYMBOL_GPL(dm_tm_commit); + +int dm_tm_new_block(struct dm_transaction_manager *tm, + struct dm_block_validator *v, + struct dm_block **result) +{ + int r; + dm_block_t new_block; + + if (tm->is_clone) + return -EWOULDBLOCK; + + r = dm_sm_new_block(tm->sm, &new_block); + if (r < 0) + return r; + + r = dm_bm_write_lock_zero(tm->bm, new_block, v, result); + if (r < 0) { + dm_sm_dec_block(tm->sm, new_block); + return r; + } + + /* + * New blocks count as shadows in that they don't need to be + * shadowed again. + */ + insert_shadow(tm, new_block); + + return 0; +} + +static int __shadow_block(struct dm_transaction_manager *tm, dm_block_t orig, + struct dm_block_validator *v, + struct dm_block **result) +{ + int r; + dm_block_t new; + struct dm_block *orig_block; + + r = dm_sm_new_block(tm->sm, &new); + if (r < 0) + return r; + + r = dm_sm_dec_block(tm->sm, orig); + if (r < 0) + return r; + + r = dm_bm_read_lock(tm->bm, orig, v, &orig_block); + if (r < 0) + return r; + + r = dm_bm_unlock_move(orig_block, new); + if (r < 0) { + dm_bm_unlock(orig_block); + return r; + } + + return dm_bm_write_lock(tm->bm, new, v, result); +} + +int dm_tm_shadow_block(struct dm_transaction_manager *tm, dm_block_t orig, + struct dm_block_validator *v, struct dm_block **result, + int *inc_children) +{ + int r; + + if (tm->is_clone) + return -EWOULDBLOCK; + + r = dm_sm_count_is_more_than_one(tm->sm, orig, inc_children); + if (r < 0) + return r; + + if (is_shadow(tm, orig) && !*inc_children) + return dm_bm_write_lock(tm->bm, orig, v, result); + + r = __shadow_block(tm, orig, v, result); + if (r < 0) + return r; + insert_shadow(tm, dm_block_location(*result)); + + return r; +} + +int dm_tm_read_lock(struct dm_transaction_manager *tm, dm_block_t b, + struct dm_block_validator *v, + struct dm_block **blk) +{ + if (tm->is_clone) + return dm_bm_read_try_lock(tm->real->bm, b, v, blk); + + return dm_bm_read_lock(tm->bm, b, v, blk); +} + +int dm_tm_unlock(struct dm_transaction_manager *tm, struct dm_block *b) +{ + return dm_bm_unlock(b); +} +EXPORT_SYMBOL_GPL(dm_tm_unlock); + +void dm_tm_inc(struct dm_transaction_manager *tm, dm_block_t b) +{ + /* + * The non-blocking clone doesn't support this. + */ + BUG_ON(tm->is_clone); + + dm_sm_inc_block(tm->sm, b); +} +EXPORT_SYMBOL_GPL(dm_tm_inc); + +void dm_tm_dec(struct dm_transaction_manager *tm, dm_block_t b) +{ + /* + * The non-blocking clone doesn't support this. + */ + BUG_ON(tm->is_clone); + + dm_sm_dec_block(tm->sm, b); +} +EXPORT_SYMBOL_GPL(dm_tm_dec); + +int dm_tm_ref(struct dm_transaction_manager *tm, dm_block_t b, + uint32_t *result) +{ + if (tm->is_clone) + return -EWOULDBLOCK; + + return dm_sm_get_count(tm->sm, b, result); +} + +struct dm_block_manager *dm_tm_get_bm(struct dm_transaction_manager *tm) +{ + return tm->bm; +} + +/*----------------------------------------------------------------*/ + +static int dm_tm_create_internal(struct dm_block_manager *bm, + dm_block_t sb_location, + struct dm_block_validator *sb_validator, + size_t root_offset, size_t root_max_len, + struct dm_transaction_manager **tm, + struct dm_space_map **sm, + struct dm_block **sblock, + int create) +{ + int r; + struct dm_space_map *inner; + + inner = dm_sm_metadata_init(); + if (IS_ERR(inner)) + return PTR_ERR(inner); + + *tm = dm_tm_create(bm, inner); + if (IS_ERR(*tm)) { + dm_sm_destroy(inner); + return PTR_ERR(*tm); + } + + if (create) { + r = dm_bm_write_lock_zero(dm_tm_get_bm(*tm), sb_location, + sb_validator, sblock); + if (r < 0) { + DMERR("couldn't lock superblock"); + goto bad1; + } + + r = dm_sm_metadata_create(inner, *tm, dm_bm_nr_blocks(bm), + sb_location); + if (r) { + DMERR("couldn't create metadata space map"); + goto bad2; + } + + *sm = dm_sm_checker_create(inner); + if (!*sm) + goto bad2; + + } else { + r = dm_bm_write_lock(dm_tm_get_bm(*tm), sb_location, + sb_validator, sblock); + if (r < 0) { + DMERR("couldn't lock superblock"); + goto bad1; + } + + r = dm_sm_metadata_open(inner, *tm, + dm_block_data(*sblock) + root_offset, + root_max_len); + if (r) { + DMERR("couldn't open metadata space map"); + goto bad2; + } + + *sm = dm_sm_checker_create(inner); + if (!*sm) + goto bad2; + } + + return 0; + +bad2: + dm_tm_unlock(*tm, *sblock); +bad1: + dm_tm_destroy(*tm); + dm_sm_destroy(inner); + return r; +} + +int dm_tm_create_with_sm(struct dm_block_manager *bm, dm_block_t sb_location, + struct dm_block_validator *sb_validator, + struct dm_transaction_manager **tm, + struct dm_space_map **sm, struct dm_block **sblock) +{ + return dm_tm_create_internal(bm, sb_location, sb_validator, + 0, 0, tm, sm, sblock, 1); +} +EXPORT_SYMBOL_GPL(dm_tm_create_with_sm); + +int dm_tm_open_with_sm(struct dm_block_manager *bm, dm_block_t sb_location, + struct dm_block_validator *sb_validator, + size_t root_offset, size_t root_max_len, + struct dm_transaction_manager **tm, + struct dm_space_map **sm, struct dm_block **sblock) +{ + return dm_tm_create_internal(bm, sb_location, sb_validator, root_offset, + root_max_len, tm, sm, sblock, 0); +} +EXPORT_SYMBOL_GPL(dm_tm_open_with_sm); + +/*----------------------------------------------------------------*/ diff --git a/drivers/md/persistent-data/dm-transaction-manager.h b/drivers/md/persistent-data/dm-transaction-manager.h new file mode 100644 index 00000000000..6da784871db --- /dev/null +++ b/drivers/md/persistent-data/dm-transaction-manager.h @@ -0,0 +1,130 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#ifndef _LINUX_DM_TRANSACTION_MANAGER_H +#define _LINUX_DM_TRANSACTION_MANAGER_H + +#include "dm-block-manager.h" + +struct dm_transaction_manager; +struct dm_space_map; + +/*----------------------------------------------------------------*/ + +/* + * This manages the scope of a transaction. It also enforces immutability + * of the on-disk data structures by limiting access to writeable blocks. + * + * Clients should not fiddle with the block manager directly. + */ + +void dm_tm_destroy(struct dm_transaction_manager *tm); + +/* + * The non-blocking version of a transaction manager is intended for use in + * fast path code that needs to do lookups e.g. a dm mapping function. + * You create the non-blocking variant from a normal tm. The interface is + * the same, except that most functions will just return -EWOULDBLOCK. + * Methods that return void yet may block should not be called on a clone + * viz. dm_tm_inc, dm_tm_dec. Call dm_tm_destroy() as you would with a normal + * tm when you've finished with it. You may not destroy the original prior + * to clones. + */ +struct dm_transaction_manager *dm_tm_create_non_blocking_clone(struct dm_transaction_manager *real); + +/* + * We use a 2-phase commit here. + * + * i) In the first phase the block manager is told to start flushing, and + * the changes to the space map are written to disk. You should interrogate + * your particular space map to get detail of its root node etc. to be + * included in your superblock. + * + * ii) @root will be committed last. You shouldn't use more than the + * first 512 bytes of @root if you wish the transaction to survive a power + * failure. You *must* have a write lock held on @root for both stage (i) + * and (ii). The commit will drop the write lock. + */ +int dm_tm_pre_commit(struct dm_transaction_manager *tm); +int dm_tm_commit(struct dm_transaction_manager *tm, struct dm_block *root); + +/* + * These methods are the only way to get hold of a writeable block. + */ + +/* + * dm_tm_new_block() is pretty self-explanatory. Make sure you do actually + * write to the whole of @data before you unlock, otherwise you could get + * a data leak. (The other option is for tm_new_block() to zero new blocks + * before handing them out, which will be redundant in most, if not all, + * cases). + * Zeroes the new block and returns with write lock held. + */ +int dm_tm_new_block(struct dm_transaction_manager *tm, + struct dm_block_validator *v, + struct dm_block **result); + +/* + * dm_tm_shadow_block() allocates a new block and copies the data from @orig + * to it. It then decrements the reference count on original block. Use + * this to update the contents of a block in a data structure, don't + * confuse this with a clone - you shouldn't access the orig block after + * this operation. Because the tm knows the scope of the transaction it + * can optimise requests for a shadow of a shadow to a no-op. Don't forget + * to unlock when you've finished with the shadow. + * + * The @inc_children flag is used to tell the caller whether it needs to + * adjust reference counts for children. (Data in the block may refer to + * other blocks.) + * + * Shadowing implicitly drops a reference on @orig so you must not have + * it locked when you call this. + */ +int dm_tm_shadow_block(struct dm_transaction_manager *tm, dm_block_t orig, + struct dm_block_validator *v, + struct dm_block **result, int *inc_children); + +/* + * Read access. You can lock any block you want. If there's a write lock + * on it outstanding then it'll block. + */ +int dm_tm_read_lock(struct dm_transaction_manager *tm, dm_block_t b, + struct dm_block_validator *v, + struct dm_block **result); + +int dm_tm_unlock(struct dm_transaction_manager *tm, struct dm_block *b); + +/* + * Functions for altering the reference count of a block directly. + */ +void dm_tm_inc(struct dm_transaction_manager *tm, dm_block_t b); + +void dm_tm_dec(struct dm_transaction_manager *tm, dm_block_t b); + +int dm_tm_ref(struct dm_transaction_manager *tm, dm_block_t b, + uint32_t *result); + +struct dm_block_manager *dm_tm_get_bm(struct dm_transaction_manager *tm); + +/* + * A little utility that ties the knot by producing a transaction manager + * that has a space map managed by the transaction manager... + * + * Returns a tm that has an open transaction to write the new disk sm. + * Caller should store the new sm root and commit. + */ +int dm_tm_create_with_sm(struct dm_block_manager *bm, dm_block_t sb_location, + struct dm_block_validator *sb_validator, + struct dm_transaction_manager **tm, + struct dm_space_map **sm, struct dm_block **sblock); + +int dm_tm_open_with_sm(struct dm_block_manager *bm, dm_block_t sb_location, + struct dm_block_validator *sb_validator, + size_t root_offset, size_t root_max_len, + struct dm_transaction_manager **tm, + struct dm_space_map **sm, struct dm_block **sblock); + +#endif /* _LINUX_DM_TRANSACTION_MANAGER_H */ diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c index 0eb08a4df75..7294bd115e3 100644 --- a/drivers/md/raid0.c +++ b/drivers/md/raid0.c @@ -20,6 +20,7 @@ #include <linux/blkdev.h> #include <linux/seq_file.h> +#include <linux/module.h> #include <linux/slab.h> #include "md.h" #include "raid0.h" @@ -468,7 +469,7 @@ static inline int is_io_in_chunk_boundary(struct mddev *mddev, } } -static int raid0_make_request(struct mddev *mddev, struct bio *bio) +static void raid0_make_request(struct mddev *mddev, struct bio *bio) { unsigned int chunk_sects; sector_t sector_offset; @@ -477,7 +478,7 @@ static int raid0_make_request(struct mddev *mddev, struct bio *bio) if (unlikely(bio->bi_rw & REQ_FLUSH)) { md_flush_request(mddev, bio); - return 0; + return; } chunk_sects = mddev->chunk_sectors; @@ -497,13 +498,10 @@ static int raid0_make_request(struct mddev *mddev, struct bio *bio) else bp = bio_split(bio, chunk_sects - sector_div(sector, chunk_sects)); - if (raid0_make_request(mddev, &bp->bio1)) - generic_make_request(&bp->bio1); - if (raid0_make_request(mddev, &bp->bio2)) - generic_make_request(&bp->bio2); - + raid0_make_request(mddev, &bp->bio1); + raid0_make_request(mddev, &bp->bio2); bio_pair_release(bp); - return 0; + return; } sector_offset = bio->bi_sector; @@ -513,10 +511,9 @@ static int raid0_make_request(struct mddev *mddev, struct bio *bio) bio->bi_bdev = tmp_dev->bdev; bio->bi_sector = sector_offset + zone->dev_start + tmp_dev->data_offset; - /* - * Let the main block layer submit the IO and resolve recursion: - */ - return 1; + + generic_make_request(bio); + return; bad_map: printk("md/raid0:%s: make_request bug: can't convert block across chunks" @@ -525,7 +522,7 @@ bad_map: (unsigned long long)bio->bi_sector, bio->bi_size >> 10); bio_io_error(bio); - return 0; + return; } static void raid0_status(struct seq_file *seq, struct mddev *mddev) diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index 4602fc57c96..ede2461e79c 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -34,6 +34,7 @@ #include <linux/slab.h> #include <linux/delay.h> #include <linux/blkdev.h> +#include <linux/module.h> #include <linux/seq_file.h> #include <linux/ratelimit.h> #include "md.h" @@ -807,7 +808,7 @@ do_sync_io: pr_debug("%dB behind alloc failed, doing sync I/O\n", bio->bi_size); } -static int make_request(struct mddev *mddev, struct bio * bio) +static void make_request(struct mddev *mddev, struct bio * bio) { struct r1conf *conf = mddev->private; struct mirror_info *mirror; @@ -892,7 +893,7 @@ read_again: if (rdisk < 0) { /* couldn't find anywhere to read from */ raid_end_bio_io(r1_bio); - return 0; + return; } mirror = conf->mirrors + rdisk; @@ -950,7 +951,7 @@ read_again: goto read_again; } else generic_make_request(read_bio); - return 0; + return; } /* @@ -1151,8 +1152,6 @@ read_again: if (do_sync || !bitmap || !plugged) md_wakeup_thread(mddev->thread); - - return 0; } static void status(struct seq_file *seq, struct mddev *mddev) @@ -2193,7 +2192,6 @@ static sector_t sync_request(struct mddev *mddev, sector_t sector_nr, int *skipp bio->bi_next = NULL; bio->bi_flags &= ~(BIO_POOL_MASK-1); bio->bi_flags |= 1 << BIO_UPTODATE; - bio->bi_comp_cpu = -1; bio->bi_rw = READ; bio->bi_vcnt = 0; bio->bi_idx = 0; diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index c025a8276dc..685ddf325ee 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -21,6 +21,7 @@ #include <linux/slab.h> #include <linux/delay.h> #include <linux/blkdev.h> +#include <linux/module.h> #include <linux/seq_file.h> #include <linux/ratelimit.h> #include "md.h" @@ -842,7 +843,7 @@ static void unfreeze_array(struct r10conf *conf) spin_unlock_irq(&conf->resync_lock); } -static int make_request(struct mddev *mddev, struct bio * bio) +static void make_request(struct mddev *mddev, struct bio * bio) { struct r10conf *conf = mddev->private; struct mirror_info *mirror; @@ -861,7 +862,7 @@ static int make_request(struct mddev *mddev, struct bio * bio) if (unlikely(bio->bi_rw & REQ_FLUSH)) { md_flush_request(mddev, bio); - return 0; + return; } /* If this request crosses a chunk boundary, we need to @@ -893,10 +894,8 @@ static int make_request(struct mddev *mddev, struct bio * bio) conf->nr_waiting++; spin_unlock_irq(&conf->resync_lock); - if (make_request(mddev, &bp->bio1)) - generic_make_request(&bp->bio1); - if (make_request(mddev, &bp->bio2)) - generic_make_request(&bp->bio2); + make_request(mddev, &bp->bio1); + make_request(mddev, &bp->bio2); spin_lock_irq(&conf->resync_lock); conf->nr_waiting--; @@ -904,14 +903,14 @@ static int make_request(struct mddev *mddev, struct bio * bio) spin_unlock_irq(&conf->resync_lock); bio_pair_release(bp); - return 0; + return; bad_map: printk("md/raid10:%s: make_request bug: can't convert block across chunks" " or bigger than %dk %llu %d\n", mdname(mddev), chunk_sects/2, (unsigned long long)bio->bi_sector, bio->bi_size >> 10); bio_io_error(bio); - return 0; + return; } md_write_start(mddev, bio); @@ -954,7 +953,7 @@ read_again: slot = r10_bio->read_slot; if (disk < 0) { raid_end_bio_io(r10_bio); - return 0; + return; } mirror = conf->mirrors + disk; @@ -1002,7 +1001,7 @@ read_again: goto read_again; } else generic_make_request(read_bio); - return 0; + return; } /* @@ -1176,7 +1175,6 @@ retry_write: if (do_sync || !mddev->bitmap || !plugged) md_wakeup_thread(mddev->thread); - return 0; } static void status(struct seq_file *seq, struct mddev *mddev) diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index f6fe053a5be..472aedfb07c 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -47,6 +47,7 @@ #include <linux/kthread.h> #include <linux/raid/pq.h> #include <linux/async_tx.h> +#include <linux/module.h> #include <linux/async.h> #include <linux/seq_file.h> #include <linux/cpu.h> @@ -3688,7 +3689,7 @@ static struct stripe_head *__get_priority_stripe(struct r5conf *conf) return sh; } -static int make_request(struct mddev *mddev, struct bio * bi) +static void make_request(struct mddev *mddev, struct bio * bi) { struct r5conf *conf = mddev->private; int dd_idx; @@ -3701,7 +3702,7 @@ static int make_request(struct mddev *mddev, struct bio * bi) if (unlikely(bi->bi_rw & REQ_FLUSH)) { md_flush_request(mddev, bi); - return 0; + return; } md_write_start(mddev, bi); @@ -3709,7 +3710,7 @@ static int make_request(struct mddev *mddev, struct bio * bi) if (rw == READ && mddev->reshape_position == MaxSector && chunk_aligned_read(mddev,bi)) - return 0; + return; logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1); last_sector = bi->bi_sector + (bi->bi_size>>9); @@ -3844,8 +3845,6 @@ static int make_request(struct mddev *mddev, struct bio * bi) bio_endio(bi, 0); } - - return 0; } static sector_t raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks); |