diff options
Diffstat (limited to 'fs/ocfs2/dlmfs/dlmfs.c')
| -rw-r--r-- | fs/ocfs2/dlmfs/dlmfs.c | 715 |
1 files changed, 715 insertions, 0 deletions
diff --git a/fs/ocfs2/dlmfs/dlmfs.c b/fs/ocfs2/dlmfs/dlmfs.c new file mode 100644 index 00000000000..1b0de157a08 --- /dev/null +++ b/fs/ocfs2/dlmfs/dlmfs.c @@ -0,0 +1,715 @@ +/* -*- mode: c; c-basic-offset: 8; -*- + * vim: noexpandtab sw=8 ts=8 sts=0: + * + * dlmfs.c + * + * Code which implements the kernel side of a minimal userspace + * interface to our DLM. This file handles the virtual file system + * used for communication with userspace. Credit should go to ramfs, + * which was a template for the fs side of this module. + * + * Copyright (C) 2003, 2004 Oracle. All rights reserved. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public + * License along with this program; if not, write to the + * Free Software Foundation, Inc., 59 Temple Place - Suite 330, + * Boston, MA 021110-1307, USA. + */ + +/* Simple VFS hooks based on: */ +/* + * Resizable simple ram filesystem for Linux. + * + * Copyright (C) 2000 Linus Torvalds. + * 2000 Transmeta Corp. + */ + +#include <linux/module.h> +#include <linux/fs.h> +#include <linux/pagemap.h> +#include <linux/types.h> +#include <linux/slab.h> +#include <linux/highmem.h> +#include <linux/init.h> +#include <linux/string.h> +#include <linux/backing-dev.h> +#include <linux/poll.h> + +#include <asm/uaccess.h> + +#include "stackglue.h" +#include "userdlm.h" +#include "dlmfsver.h" + +#define MLOG_MASK_PREFIX ML_DLMFS +#include "cluster/masklog.h" + + +static const struct super_operations dlmfs_ops; +static const struct file_operations dlmfs_file_operations; +static const struct inode_operations dlmfs_dir_inode_operations; +static const struct inode_operations dlmfs_root_inode_operations; +static const struct inode_operations dlmfs_file_inode_operations; +static struct kmem_cache *dlmfs_inode_cache; + +struct workqueue_struct *user_dlm_worker; + + + +/* + * These are the ABI capabilities of dlmfs. + * + * Over time, dlmfs has added some features that were not part of the + * initial ABI. Unfortunately, some of these features are not detectable + * via standard usage. For example, Linux's default poll always returns + * POLLIN, so there is no way for a caller of poll(2) to know when dlmfs + * added poll support. Instead, we provide this list of new capabilities. + * + * Capabilities is a read-only attribute. We do it as a module parameter + * so we can discover it whether dlmfs is built in, loaded, or even not + * loaded. + * + * The ABI features are local to this machine's dlmfs mount. This is + * distinct from the locking protocol, which is concerned with inter-node + * interaction. + * + * Capabilities: + * - bast : POLLIN against the file descriptor of a held lock + * signifies a bast fired on the lock. + */ +#define DLMFS_CAPABILITIES "bast stackglue" +extern int param_set_dlmfs_capabilities(const char *val, + struct kernel_param *kp) +{ + printk(KERN_ERR "%s: readonly parameter\n", kp->name); + return -EINVAL; +} +static int param_get_dlmfs_capabilities(char *buffer, + struct kernel_param *kp) +{ + return strlcpy(buffer, DLMFS_CAPABILITIES, + strlen(DLMFS_CAPABILITIES) + 1); +} +module_param_call(capabilities, param_set_dlmfs_capabilities, + param_get_dlmfs_capabilities, NULL, 0444); +MODULE_PARM_DESC(capabilities, DLMFS_CAPABILITIES); + + +/* + * decodes a set of open flags into a valid lock level and a set of flags. + * returns < 0 if we have invalid flags + * flags which mean something to us: + * O_RDONLY -> PRMODE level + * O_WRONLY -> EXMODE level + * + * O_NONBLOCK -> LKM_NOQUEUE + */ +static int dlmfs_decode_open_flags(int open_flags, + int *level, + int *flags) +{ + if (open_flags & (O_WRONLY|O_RDWR)) + *level = LKM_EXMODE; + else + *level = LKM_PRMODE; + + *flags = 0; + if (open_flags & O_NONBLOCK) + *flags |= LKM_NOQUEUE; + + return 0; +} + +static int dlmfs_file_open(struct inode *inode, + struct file *file) +{ + int status, level, flags; + struct dlmfs_filp_private *fp = NULL; + struct dlmfs_inode_private *ip; + + if (S_ISDIR(inode->i_mode)) + BUG(); + + mlog(0, "open called on inode %lu, flags 0x%x\n", inode->i_ino, + file->f_flags); + + status = dlmfs_decode_open_flags(file->f_flags, &level, &flags); + if (status < 0) + goto bail; + + /* We don't want to honor O_APPEND at read/write time as it + * doesn't make sense for LVB writes. */ + file->f_flags &= ~O_APPEND; + + fp = kmalloc(sizeof(*fp), GFP_NOFS); + if (!fp) { + status = -ENOMEM; + goto bail; + } + fp->fp_lock_level = level; + + ip = DLMFS_I(inode); + + status = user_dlm_cluster_lock(&ip->ip_lockres, level, flags); + if (status < 0) { + /* this is a strange error to return here but I want + * to be able userspace to be able to distinguish a + * valid lock request from one that simply couldn't be + * granted. */ + if (flags & LKM_NOQUEUE && status == -EAGAIN) + status = -ETXTBSY; + kfree(fp); + goto bail; + } + + file->private_data = fp; +bail: + return status; +} + +static int dlmfs_file_release(struct inode *inode, + struct file *file) +{ + int level, status; + struct dlmfs_inode_private *ip = DLMFS_I(inode); + struct dlmfs_filp_private *fp = + (struct dlmfs_filp_private *) file->private_data; + + if (S_ISDIR(inode->i_mode)) + BUG(); + + mlog(0, "close called on inode %lu\n", inode->i_ino); + + status = 0; + if (fp) { + level = fp->fp_lock_level; + if (level != LKM_IVMODE) + user_dlm_cluster_unlock(&ip->ip_lockres, level); + + kfree(fp); + file->private_data = NULL; + } + + return 0; +} + +/* + * We do ->setattr() just to override size changes. Our size is the size + * of the LVB and nothing else. + */ +static int dlmfs_file_setattr(struct dentry *dentry, struct iattr *attr) +{ + int error; + struct inode *inode = dentry->d_inode; + + attr->ia_valid &= ~ATTR_SIZE; + error = inode_change_ok(inode, attr); + if (!error) + error = inode_setattr(inode, attr); + + return error; +} + +static unsigned int dlmfs_file_poll(struct file *file, poll_table *wait) +{ + int event = 0; + struct inode *inode = file->f_path.dentry->d_inode; + struct dlmfs_inode_private *ip = DLMFS_I(inode); + + poll_wait(file, &ip->ip_lockres.l_event, wait); + + spin_lock(&ip->ip_lockres.l_lock); + if (ip->ip_lockres.l_flags & USER_LOCK_BLOCKED) + event = POLLIN | POLLRDNORM; + spin_unlock(&ip->ip_lockres.l_lock); + + return event; +} + +static ssize_t dlmfs_file_read(struct file *filp, + char __user *buf, + size_t count, + loff_t *ppos) +{ + int bytes_left; + ssize_t readlen, got; + char *lvb_buf; + struct inode *inode = filp->f_path.dentry->d_inode; + + mlog(0, "inode %lu, count = %zu, *ppos = %llu\n", + inode->i_ino, count, *ppos); + + if (*ppos >= i_size_read(inode)) + return 0; + + if (!count) + return 0; + + if (!access_ok(VERIFY_WRITE, buf, count)) + return -EFAULT; + + /* don't read past the lvb */ + if ((count + *ppos) > i_size_read(inode)) + readlen = i_size_read(inode) - *ppos; + else + readlen = count - *ppos; + + lvb_buf = kmalloc(readlen, GFP_NOFS); + if (!lvb_buf) + return -ENOMEM; + + got = user_dlm_read_lvb(inode, lvb_buf, readlen); + if (got) { + BUG_ON(got != readlen); + bytes_left = __copy_to_user(buf, lvb_buf, readlen); + readlen -= bytes_left; + } else + readlen = 0; + + kfree(lvb_buf); + + *ppos = *ppos + readlen; + + mlog(0, "read %zd bytes\n", readlen); + return readlen; +} + +static ssize_t dlmfs_file_write(struct file *filp, + const char __user *buf, + size_t count, + loff_t *ppos) +{ + int bytes_left; + ssize_t writelen; + char *lvb_buf; + struct inode *inode = filp->f_path.dentry->d_inode; + + mlog(0, "inode %lu, count = %zu, *ppos = %llu\n", + inode->i_ino, count, *ppos); + + if (*ppos >= i_size_read(inode)) + return -ENOSPC; + + if (!count) + return 0; + + if (!access_ok(VERIFY_READ, buf, count)) + return -EFAULT; + + /* don't write past the lvb */ + if ((count + *ppos) > i_size_read(inode)) + writelen = i_size_read(inode) - *ppos; + else + writelen = count - *ppos; + + lvb_buf = kmalloc(writelen, GFP_NOFS); + if (!lvb_buf) + return -ENOMEM; + + bytes_left = copy_from_user(lvb_buf, buf, writelen); + writelen -= bytes_left; + if (writelen) + user_dlm_write_lvb(inode, lvb_buf, writelen); + + kfree(lvb_buf); + + *ppos = *ppos + writelen; + mlog(0, "wrote %zd bytes\n", writelen); + return writelen; +} + +static void dlmfs_init_once(void *foo) +{ + struct dlmfs_inode_private *ip = + (struct dlmfs_inode_private *) foo; + + ip->ip_conn = NULL; + ip->ip_parent = NULL; + + inode_init_once(&ip->ip_vfs_inode); +} + +static struct inode *dlmfs_alloc_inode(struct super_block *sb) +{ + struct dlmfs_inode_private *ip; + + ip = kmem_cache_alloc(dlmfs_inode_cache, GFP_NOFS); + if (!ip) + return NULL; + + return &ip->ip_vfs_inode; +} + +static void dlmfs_destroy_inode(struct inode *inode) +{ + kmem_cache_free(dlmfs_inode_cache, DLMFS_I(inode)); +} + +static void dlmfs_clear_inode(struct inode *inode) +{ + int status; + struct dlmfs_inode_private *ip; + + if (!inode) + return; + + mlog(0, "inode %lu\n", inode->i_ino); + + ip = DLMFS_I(inode); + + if (S_ISREG(inode->i_mode)) { + status = user_dlm_destroy_lock(&ip->ip_lockres); + if (status < 0) + mlog_errno(status); + iput(ip->ip_parent); + goto clear_fields; + } + + mlog(0, "we're a directory, ip->ip_conn = 0x%p\n", ip->ip_conn); + /* we must be a directory. If required, lets unregister the + * dlm context now. */ + if (ip->ip_conn) + user_dlm_unregister(ip->ip_conn); +clear_fields: + ip->ip_parent = NULL; + ip->ip_conn = NULL; +} + +static struct backing_dev_info dlmfs_backing_dev_info = { + .name = "ocfs2-dlmfs", + .ra_pages = 0, /* No readahead */ + .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK, +}; + +static struct inode *dlmfs_get_root_inode(struct super_block *sb) +{ + struct inode *inode = new_inode(sb); + int mode = S_IFDIR | 0755; + struct dlmfs_inode_private *ip; + + if (inode) { + ip = DLMFS_I(inode); + + inode->i_mode = mode; + inode->i_uid = current_fsuid(); + inode->i_gid = current_fsgid(); + inode->i_mapping->backing_dev_info = &dlmfs_backing_dev_info; + inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; + inc_nlink(inode); + + inode->i_fop = &simple_dir_operations; + inode->i_op = &dlmfs_root_inode_operations; + } + + return inode; +} + +static struct inode *dlmfs_get_inode(struct inode *parent, + struct dentry *dentry, + int mode) +{ + struct super_block *sb = parent->i_sb; + struct inode * inode = new_inode(sb); + struct dlmfs_inode_private *ip; + + if (!inode) + return NULL; + + inode->i_mode = mode; + inode->i_uid = current_fsuid(); + inode->i_gid = current_fsgid(); + inode->i_mapping->backing_dev_info = &dlmfs_backing_dev_info; + inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; + + ip = DLMFS_I(inode); + ip->ip_conn = DLMFS_I(parent)->ip_conn; + + switch (mode & S_IFMT) { + default: + /* for now we don't support anything other than + * directories and regular files. */ + BUG(); + break; + case S_IFREG: + inode->i_op = &dlmfs_file_inode_operations; + inode->i_fop = &dlmfs_file_operations; + + i_size_write(inode, DLM_LVB_LEN); + + user_dlm_lock_res_init(&ip->ip_lockres, dentry); + + /* released at clear_inode time, this insures that we + * get to drop the dlm reference on each lock *before* + * we call the unregister code for releasing parent + * directories. */ + ip->ip_parent = igrab(parent); + BUG_ON(!ip->ip_parent); + break; + case S_IFDIR: + inode->i_op = &dlmfs_dir_inode_operations; + inode->i_fop = &simple_dir_operations; + + /* directory inodes start off with i_nlink == + * 2 (for "." entry) */ + inc_nlink(inode); + break; + } + + if (parent->i_mode & S_ISGID) { + inode->i_gid = parent->i_gid; + if (S_ISDIR(mode)) + inode->i_mode |= S_ISGID; + } + + return inode; +} + +/* + * File creation. Allocate an inode, and we're done.. + */ +/* SMP-safe */ +static int dlmfs_mkdir(struct inode * dir, + struct dentry * dentry, + int mode) +{ + int status; + struct inode *inode = NULL; + struct qstr *domain = &dentry->d_name; + struct dlmfs_inode_private *ip; + struct ocfs2_cluster_connection *conn; + + mlog(0, "mkdir %.*s\n", domain->len, domain->name); + + /* verify that we have a proper domain */ + if (domain->len >= GROUP_NAME_MAX) { + status = -EINVAL; + mlog(ML_ERROR, "invalid domain name for directory.\n"); + goto bail; + } + + inode = dlmfs_get_inode(dir, dentry, mode | S_IFDIR); + if (!inode) { + status = -ENOMEM; + mlog_errno(status); + goto bail; + } + + ip = DLMFS_I(inode); + + conn = user_dlm_register(domain); + if (IS_ERR(conn)) { + status = PTR_ERR(conn); + mlog(ML_ERROR, "Error %d could not register domain \"%.*s\"\n", + status, domain->len, domain->name); + goto bail; + } + ip->ip_conn = conn; + + inc_nlink(dir); + d_instantiate(dentry, inode); + dget(dentry); /* Extra count - pin the dentry in core */ + + status = 0; +bail: + if (status < 0) + iput(inode); + return status; +} + +static int dlmfs_create(struct inode *dir, + struct dentry *dentry, + int mode, + struct nameidata *nd) +{ + int status = 0; + struct inode *inode; + struct qstr *name = &dentry->d_name; + + mlog(0, "create %.*s\n", name->len, name->name); + + /* verify name is valid and doesn't contain any dlm reserved + * characters */ + if (name->len >= USER_DLM_LOCK_ID_MAX_LEN || + name->name[0] == '$') { + status = -EINVAL; + mlog(ML_ERROR, "invalid lock name, %.*s\n", name->len, + name->name); + goto bail; + } + + inode = dlmfs_get_inode(dir, dentry, mode | S_IFREG); + if (!inode) { + status = -ENOMEM; + mlog_errno(status); + goto bail; + } + + d_instantiate(dentry, inode); + dget(dentry); /* Extra count - pin the dentry in core */ +bail: + return status; +} + +static int dlmfs_unlink(struct inode *dir, + struct dentry *dentry) +{ + int status; + struct inode *inode = dentry->d_inode; + + mlog(0, "unlink inode %lu\n", inode->i_ino); + + /* if there are no current holders, or none that are waiting + * to acquire a lock, this basically destroys our lockres. */ + status = user_dlm_destroy_lock(&DLMFS_I(inode)->ip_lockres); + if (status < 0) { + mlog(ML_ERROR, "unlink %.*s, error %d from destroy\n", + dentry->d_name.len, dentry->d_name.name, status); + goto bail; + } + status = simple_unlink(dir, dentry); +bail: + return status; +} + +static int dlmfs_fill_super(struct super_block * sb, + void * data, + int silent) +{ + struct inode * inode; + struct dentry * root; + + sb->s_maxbytes = MAX_LFS_FILESIZE; + sb->s_blocksize = PAGE_CACHE_SIZE; + sb->s_blocksize_bits = PAGE_CACHE_SHIFT; + sb->s_magic = DLMFS_MAGIC; + sb->s_op = &dlmfs_ops; + inode = dlmfs_get_root_inode(sb); + if (!inode) + return -ENOMEM; + + root = d_alloc_root(inode); + if (!root) { + iput(inode); + return -ENOMEM; + } + sb->s_root = root; + return 0; +} + +static const struct file_operations dlmfs_file_operations = { + .open = dlmfs_file_open, + .release = dlmfs_file_release, + .poll = dlmfs_file_poll, + .read = dlmfs_file_read, + .write = dlmfs_file_write, +}; + +static const struct inode_operations dlmfs_dir_inode_operations = { + .create = dlmfs_create, + .lookup = simple_lookup, + .unlink = dlmfs_unlink, +}; + +/* this way we can restrict mkdir to only the toplevel of the fs. */ +static const struct inode_operations dlmfs_root_inode_operations = { + .lookup = simple_lookup, + .mkdir = dlmfs_mkdir, + .rmdir = simple_rmdir, +}; + +static const struct super_operations dlmfs_ops = { + .statfs = simple_statfs, + .alloc_inode = dlmfs_alloc_inode, + .destroy_inode = dlmfs_destroy_inode, + .clear_inode = dlmfs_clear_inode, + .drop_inode = generic_delete_inode, +}; + +static const struct inode_operations dlmfs_file_inode_operations = { + .getattr = simple_getattr, + .setattr = dlmfs_file_setattr, +}; + +static int dlmfs_get_sb(struct file_system_type *fs_type, + int flags, const char *dev_name, void *data, struct vfsmount *mnt) +{ + return get_sb_nodev(fs_type, flags, data, dlmfs_fill_super, mnt); +} + +static struct file_system_type dlmfs_fs_type = { + .owner = THIS_MODULE, + .name = "ocfs2_dlmfs", + .get_sb = dlmfs_get_sb, + .kill_sb = kill_litter_super, +}; + +static int __init init_dlmfs_fs(void) +{ + int status; + int cleanup_inode = 0, cleanup_worker = 0; + + dlmfs_print_version(); + + status = bdi_init(&dlmfs_backing_dev_info); + if (status) + return status; + + dlmfs_inode_cache = kmem_cache_create("dlmfs_inode_cache", + sizeof(struct dlmfs_inode_private), + 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| + SLAB_MEM_SPREAD), + dlmfs_init_once); + if (!dlmfs_inode_cache) { + status = -ENOMEM; + goto bail; + } + cleanup_inode = 1; + + user_dlm_worker = create_singlethread_workqueue("user_dlm"); + if (!user_dlm_worker) { + status = -ENOMEM; + goto bail; + } + cleanup_worker = 1; + + user_dlm_set_locking_protocol(); + status = register_filesystem(&dlmfs_fs_type); +bail: + if (status) { + if (cleanup_inode) + kmem_cache_destroy(dlmfs_inode_cache); + if (cleanup_worker) + destroy_workqueue(user_dlm_worker); + bdi_destroy(&dlmfs_backing_dev_info); + } else + printk("OCFS2 User DLM kernel interface loaded\n"); + return status; +} + +static void __exit exit_dlmfs_fs(void) +{ + unregister_filesystem(&dlmfs_fs_type); + + flush_workqueue(user_dlm_worker); + destroy_workqueue(user_dlm_worker); + + kmem_cache_destroy(dlmfs_inode_cache); + + bdi_destroy(&dlmfs_backing_dev_info); +} + +MODULE_AUTHOR("Oracle"); +MODULE_LICENSE("GPL"); + +module_init(init_dlmfs_fs) +module_exit(exit_dlmfs_fs) |