diff options
Diffstat (limited to 'fs/btrfs/super.c')
| -rw-r--r-- | fs/btrfs/super.c | 1305 |
1 files changed, 1305 insertions, 0 deletions
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c new file mode 100644 index 00000000..15634d46 --- /dev/null +++ b/fs/btrfs/super.c @@ -0,0 +1,1305 @@ +/* + * Copyright (C) 2007 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 v2 as published by the Free Software Foundation. + * + * 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. + */ + +#include <linux/blkdev.h> +#include <linux/module.h> +#include <linux/buffer_head.h> +#include <linux/fs.h> +#include <linux/pagemap.h> +#include <linux/highmem.h> +#include <linux/time.h> +#include <linux/init.h> +#include <linux/seq_file.h> +#include <linux/string.h> +#include <linux/backing-dev.h> +#include <linux/mount.h> +#include <linux/mpage.h> +#include <linux/swap.h> +#include <linux/writeback.h> +#include <linux/statfs.h> +#include <linux/compat.h> +#include <linux/parser.h> +#include <linux/ctype.h> +#include <linux/namei.h> +#include <linux/miscdevice.h> +#include <linux/magic.h> +#include <linux/slab.h> +#include <linux/cleancache.h> +#include "compat.h" +#include "delayed-inode.h" +#include "ctree.h" +#include "disk-io.h" +#include "transaction.h" +#include "btrfs_inode.h" +#include "ioctl.h" +#include "print-tree.h" +#include "xattr.h" +#include "volumes.h" +#include "version.h" +#include "export.h" +#include "compression.h" + +#define CREATE_TRACE_POINTS +#include <trace/events/btrfs.h> + +static const struct super_operations btrfs_super_ops; + +static const char *btrfs_decode_error(struct btrfs_fs_info *fs_info, int errno, + char nbuf[16]) +{ + char *errstr = NULL; + + switch (errno) { + case -EIO: + errstr = "IO failure"; + break; + case -ENOMEM: + errstr = "Out of memory"; + break; + case -EROFS: + errstr = "Readonly filesystem"; + break; + default: + if (nbuf) { + if (snprintf(nbuf, 16, "error %d", -errno) >= 0) + errstr = nbuf; + } + break; + } + + return errstr; +} + +static void __save_error_info(struct btrfs_fs_info *fs_info) +{ + /* + * today we only save the error info into ram. Long term we'll + * also send it down to the disk + */ + fs_info->fs_state = BTRFS_SUPER_FLAG_ERROR; +} + +/* NOTE: + * We move write_super stuff at umount in order to avoid deadlock + * for umount hold all lock. + */ +static void save_error_info(struct btrfs_fs_info *fs_info) +{ + __save_error_info(fs_info); +} + +/* btrfs handle error by forcing the filesystem readonly */ +static void btrfs_handle_error(struct btrfs_fs_info *fs_info) +{ + struct super_block *sb = fs_info->sb; + + if (sb->s_flags & MS_RDONLY) + return; + + if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) { + sb->s_flags |= MS_RDONLY; + printk(KERN_INFO "btrfs is forced readonly\n"); + } +} + +/* + * __btrfs_std_error decodes expected errors from the caller and + * invokes the approciate error response. + */ +void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function, + unsigned int line, int errno) +{ + struct super_block *sb = fs_info->sb; + char nbuf[16]; + const char *errstr; + + /* + * Special case: if the error is EROFS, and we're already + * under MS_RDONLY, then it is safe here. + */ + if (errno == -EROFS && (sb->s_flags & MS_RDONLY)) + return; + + errstr = btrfs_decode_error(fs_info, errno, nbuf); + printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: %s\n", + sb->s_id, function, line, errstr); + save_error_info(fs_info); + + btrfs_handle_error(fs_info); +} + +static void btrfs_put_super(struct super_block *sb) +{ + struct btrfs_root *root = btrfs_sb(sb); + int ret; + + ret = close_ctree(root); + sb->s_fs_info = NULL; + + (void)ret; /* FIXME: need to fix VFS to return error? */ +} + +enum { + Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum, + Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd, + Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress, + Opt_compress_type, Opt_compress_force, Opt_compress_force_type, + Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard, + Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed, + Opt_enospc_debug, Opt_subvolrootid, Opt_defrag, + Opt_inode_cache, Opt_err, +}; + +static match_table_t tokens = { + {Opt_degraded, "degraded"}, + {Opt_subvol, "subvol=%s"}, + {Opt_subvolid, "subvolid=%d"}, + {Opt_device, "device=%s"}, + {Opt_nodatasum, "nodatasum"}, + {Opt_nodatacow, "nodatacow"}, + {Opt_nobarrier, "nobarrier"}, + {Opt_max_inline, "max_inline=%s"}, + {Opt_alloc_start, "alloc_start=%s"}, + {Opt_thread_pool, "thread_pool=%d"}, + {Opt_compress, "compress"}, + {Opt_compress_type, "compress=%s"}, + {Opt_compress_force, "compress-force"}, + {Opt_compress_force_type, "compress-force=%s"}, + {Opt_ssd, "ssd"}, + {Opt_ssd_spread, "ssd_spread"}, + {Opt_nossd, "nossd"}, + {Opt_noacl, "noacl"}, + {Opt_notreelog, "notreelog"}, + {Opt_flushoncommit, "flushoncommit"}, + {Opt_ratio, "metadata_ratio=%d"}, + {Opt_discard, "discard"}, + {Opt_space_cache, "space_cache"}, + {Opt_clear_cache, "clear_cache"}, + {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"}, + {Opt_enospc_debug, "enospc_debug"}, + {Opt_subvolrootid, "subvolrootid=%d"}, + {Opt_defrag, "autodefrag"}, + {Opt_inode_cache, "inode_cache"}, + {Opt_err, NULL}, +}; + +/* + * Regular mount options parser. Everything that is needed only when + * reading in a new superblock is parsed here. + */ +int btrfs_parse_options(struct btrfs_root *root, char *options) +{ + struct btrfs_fs_info *info = root->fs_info; + substring_t args[MAX_OPT_ARGS]; + char *p, *num, *orig; + int intarg; + int ret = 0; + char *compress_type; + bool compress_force = false; + + if (!options) + return 0; + + /* + * strsep changes the string, duplicate it because parse_options + * gets called twice + */ + options = kstrdup(options, GFP_NOFS); + if (!options) + return -ENOMEM; + + orig = options; + + while ((p = strsep(&options, ",")) != NULL) { + int token; + if (!*p) + continue; + + token = match_token(p, tokens, args); + switch (token) { + case Opt_degraded: + printk(KERN_INFO "btrfs: allowing degraded mounts\n"); + btrfs_set_opt(info->mount_opt, DEGRADED); + break; + case Opt_subvol: + case Opt_subvolid: + case Opt_subvolrootid: + case Opt_device: + /* + * These are parsed by btrfs_parse_early_options + * and can be happily ignored here. + */ + break; + case Opt_nodatasum: + printk(KERN_INFO "btrfs: setting nodatasum\n"); + btrfs_set_opt(info->mount_opt, NODATASUM); + break; + case Opt_nodatacow: + printk(KERN_INFO "btrfs: setting nodatacow\n"); + btrfs_set_opt(info->mount_opt, NODATACOW); + btrfs_set_opt(info->mount_opt, NODATASUM); + break; + case Opt_compress_force: + case Opt_compress_force_type: + compress_force = true; + case Opt_compress: + case Opt_compress_type: + if (token == Opt_compress || + token == Opt_compress_force || + strcmp(args[0].from, "zlib") == 0) { + compress_type = "zlib"; + info->compress_type = BTRFS_COMPRESS_ZLIB; + } else if (strcmp(args[0].from, "lzo") == 0) { + compress_type = "lzo"; + info->compress_type = BTRFS_COMPRESS_LZO; + } else { + ret = -EINVAL; + goto out; + } + + btrfs_set_opt(info->mount_opt, COMPRESS); + if (compress_force) { + btrfs_set_opt(info->mount_opt, FORCE_COMPRESS); + pr_info("btrfs: force %s compression\n", + compress_type); + } else + pr_info("btrfs: use %s compression\n", + compress_type); + break; + case Opt_ssd: + printk(KERN_INFO "btrfs: use ssd allocation scheme\n"); + btrfs_set_opt(info->mount_opt, SSD); + break; + case Opt_ssd_spread: + printk(KERN_INFO "btrfs: use spread ssd " + "allocation scheme\n"); + btrfs_set_opt(info->mount_opt, SSD); + btrfs_set_opt(info->mount_opt, SSD_SPREAD); + break; + case Opt_nossd: + printk(KERN_INFO "btrfs: not using ssd allocation " + "scheme\n"); + btrfs_set_opt(info->mount_opt, NOSSD); + btrfs_clear_opt(info->mount_opt, SSD); + btrfs_clear_opt(info->mount_opt, SSD_SPREAD); + break; + case Opt_nobarrier: + printk(KERN_INFO "btrfs: turning off barriers\n"); + btrfs_set_opt(info->mount_opt, NOBARRIER); + break; + case Opt_thread_pool: + intarg = 0; + match_int(&args[0], &intarg); + if (intarg) { + info->thread_pool_size = intarg; + printk(KERN_INFO "btrfs: thread pool %d\n", + info->thread_pool_size); + } + break; + case Opt_max_inline: + num = match_strdup(&args[0]); + if (num) { + info->max_inline = memparse(num, NULL); + kfree(num); + + if (info->max_inline) { + info->max_inline = max_t(u64, + info->max_inline, + root->sectorsize); + } + printk(KERN_INFO "btrfs: max_inline at %llu\n", + (unsigned long long)info->max_inline); + } + break; + case Opt_alloc_start: + num = match_strdup(&args[0]); + if (num) { + info->alloc_start = memparse(num, NULL); + kfree(num); + printk(KERN_INFO + "btrfs: allocations start at %llu\n", + (unsigned long long)info->alloc_start); + } + break; + case Opt_noacl: + root->fs_info->sb->s_flags &= ~MS_POSIXACL; + break; + case Opt_notreelog: + printk(KERN_INFO "btrfs: disabling tree log\n"); + btrfs_set_opt(info->mount_opt, NOTREELOG); + break; + case Opt_flushoncommit: + printk(KERN_INFO "btrfs: turning on flush-on-commit\n"); + btrfs_set_opt(info->mount_opt, FLUSHONCOMMIT); + break; + case Opt_ratio: + intarg = 0; + match_int(&args[0], &intarg); + if (intarg) { + info->metadata_ratio = intarg; + printk(KERN_INFO "btrfs: metadata ratio %d\n", + info->metadata_ratio); + } + break; + case Opt_discard: + btrfs_set_opt(info->mount_opt, DISCARD); + break; + case Opt_space_cache: + printk(KERN_INFO "btrfs: enabling disk space caching\n"); + btrfs_set_opt(info->mount_opt, SPACE_CACHE); + break; + case Opt_inode_cache: + printk(KERN_INFO "btrfs: enabling inode map caching\n"); + btrfs_set_opt(info->mount_opt, INODE_MAP_CACHE); + break; + case Opt_clear_cache: + printk(KERN_INFO "btrfs: force clearing of disk cache\n"); + btrfs_set_opt(info->mount_opt, CLEAR_CACHE); + break; + case Opt_user_subvol_rm_allowed: + btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED); + break; + case Opt_enospc_debug: + btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG); + break; + case Opt_defrag: + printk(KERN_INFO "btrfs: enabling auto defrag"); + btrfs_set_opt(info->mount_opt, AUTO_DEFRAG); + break; + case Opt_err: + printk(KERN_INFO "btrfs: unrecognized mount option " + "'%s'\n", p); + ret = -EINVAL; + goto out; + default: + break; + } + } +out: + kfree(orig); + return ret; +} + +/* + * Parse mount options that are required early in the mount process. + * + * All other options will be parsed on much later in the mount process and + * only when we need to allocate a new super block. + */ +static int btrfs_parse_early_options(const char *options, fmode_t flags, + void *holder, char **subvol_name, u64 *subvol_objectid, + u64 *subvol_rootid, struct btrfs_fs_devices **fs_devices) +{ + substring_t args[MAX_OPT_ARGS]; + char *opts, *orig, *p; + int error = 0; + int intarg; + + if (!options) + goto out; + + /* + * strsep changes the string, duplicate it because parse_options + * gets called twice + */ + opts = kstrdup(options, GFP_KERNEL); + if (!opts) + return -ENOMEM; + orig = opts; + + while ((p = strsep(&opts, ",")) != NULL) { + int token; + if (!*p) + continue; + + token = match_token(p, tokens, args); + switch (token) { + case Opt_subvol: + *subvol_name = match_strdup(&args[0]); + break; + case Opt_subvolid: + intarg = 0; + error = match_int(&args[0], &intarg); + if (!error) { + /* we want the original fs_tree */ + if (!intarg) + *subvol_objectid = + BTRFS_FS_TREE_OBJECTID; + else + *subvol_objectid = intarg; + } + break; + case Opt_subvolrootid: + intarg = 0; + error = match_int(&args[0], &intarg); + if (!error) { + /* we want the original fs_tree */ + if (!intarg) + *subvol_rootid = + BTRFS_FS_TREE_OBJECTID; + else + *subvol_rootid = intarg; + } + break; + case Opt_device: + error = btrfs_scan_one_device(match_strdup(&args[0]), + flags, holder, fs_devices); + if (error) + goto out_free_opts; + break; + default: + break; + } + } + + out_free_opts: + kfree(orig); + out: + /* + * If no subvolume name is specified we use the default one. Allocate + * a copy of the string "." here so that code later in the + * mount path doesn't care if it's the default volume or another one. + */ + if (!*subvol_name) { + *subvol_name = kstrdup(".", GFP_KERNEL); + if (!*subvol_name) + return -ENOMEM; + } + return error; +} + +static struct dentry *get_default_root(struct super_block *sb, + u64 subvol_objectid) +{ + struct btrfs_root *root = sb->s_fs_info; + struct btrfs_root *new_root; + struct btrfs_dir_item *di; + struct btrfs_path *path; + struct btrfs_key location; + struct inode *inode; + struct dentry *dentry; + u64 dir_id; + int new = 0; + + /* + * We have a specific subvol we want to mount, just setup location and + * go look up the root. + */ + if (subvol_objectid) { + location.objectid = subvol_objectid; + location.type = BTRFS_ROOT_ITEM_KEY; + location.offset = (u64)-1; + goto find_root; + } + + path = btrfs_alloc_path(); + if (!path) + return ERR_PTR(-ENOMEM); + path->leave_spinning = 1; + + /* + * Find the "default" dir item which points to the root item that we + * will mount by default if we haven't been given a specific subvolume + * to mount. + */ + dir_id = btrfs_super_root_dir(&root->fs_info->super_copy); + di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0); + if (IS_ERR(di)) { + btrfs_free_path(path); + return ERR_CAST(di); + } + if (!di) { + /* + * Ok the default dir item isn't there. This is weird since + * it's always been there, but don't freak out, just try and + * mount to root most subvolume. + */ + btrfs_free_path(path); + dir_id = BTRFS_FIRST_FREE_OBJECTID; + new_root = root->fs_info->fs_root; + goto setup_root; + } + + btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location); + btrfs_free_path(path); + +find_root: + new_root = btrfs_read_fs_root_no_name(root->fs_info, &location); + if (IS_ERR(new_root)) + return ERR_CAST(new_root); + + if (btrfs_root_refs(&new_root->root_item) == 0) + return ERR_PTR(-ENOENT); + + dir_id = btrfs_root_dirid(&new_root->root_item); +setup_root: + location.objectid = dir_id; + location.type = BTRFS_INODE_ITEM_KEY; + location.offset = 0; + + inode = btrfs_iget(sb, &location, new_root, &new); + if (IS_ERR(inode)) + return ERR_CAST(inode); + + /* + * If we're just mounting the root most subvol put the inode and return + * a reference to the dentry. We will have already gotten a reference + * to the inode in btrfs_fill_super so we're good to go. + */ + if (!new && sb->s_root->d_inode == inode) { + iput(inode); + return dget(sb->s_root); + } + + if (new) { + const struct qstr name = { .name = "/", .len = 1 }; + + /* + * New inode, we need to make the dentry a sibling of s_root so + * everything gets cleaned up properly on unmount. + */ + dentry = d_alloc(sb->s_root, &name); + if (!dentry) { + iput(inode); + return ERR_PTR(-ENOMEM); + } + d_splice_alias(inode, dentry); + } else { + /* + * We found the inode in cache, just find a dentry for it and + * put the reference to the inode we just got. + */ + dentry = d_find_alias(inode); + iput(inode); + } + + return dentry; +} + +static int btrfs_fill_super(struct super_block *sb, + struct btrfs_fs_devices *fs_devices, + void *data, int silent) +{ + struct inode *inode; + struct dentry *root_dentry; + struct btrfs_root *tree_root; + struct btrfs_key key; + int err; + + sb->s_maxbytes = MAX_LFS_FILESIZE; + sb->s_magic = BTRFS_SUPER_MAGIC; + sb->s_op = &btrfs_super_ops; + sb->s_d_op = &btrfs_dentry_operations; + sb->s_export_op = &btrfs_export_ops; + sb->s_xattr = btrfs_xattr_handlers; + sb->s_time_gran = 1; +#ifdef CONFIG_BTRFS_FS_POSIX_ACL + sb->s_flags |= MS_POSIXACL; +#endif + + tree_root = open_ctree(sb, fs_devices, (char *)data); + + if (IS_ERR(tree_root)) { + printk("btrfs: open_ctree failed\n"); + return PTR_ERR(tree_root); + } + sb->s_fs_info = tree_root; + + key.objectid = BTRFS_FIRST_FREE_OBJECTID; + key.type = BTRFS_INODE_ITEM_KEY; + key.offset = 0; + inode = btrfs_iget(sb, &key, tree_root->fs_info->fs_root, NULL); + if (IS_ERR(inode)) { + err = PTR_ERR(inode); + goto fail_close; + } + + root_dentry = d_alloc_root(inode); + if (!root_dentry) { + iput(inode); + err = -ENOMEM; + goto fail_close; + } + + sb->s_root = root_dentry; + + save_mount_options(sb, data); + cleancache_init_fs(sb); + return 0; + +fail_close: + close_ctree(tree_root); + return err; +} + +int btrfs_sync_fs(struct super_block *sb, int wait) +{ + struct btrfs_trans_handle *trans; + struct btrfs_root *root = btrfs_sb(sb); + int ret; + + trace_btrfs_sync_fs(wait); + + if (!wait) { + filemap_flush(root->fs_info->btree_inode->i_mapping); + return 0; + } + + btrfs_start_delalloc_inodes(root, 0); + btrfs_wait_ordered_extents(root, 0, 0); + + trans = btrfs_start_transaction(root, 0); + if (IS_ERR(trans)) + return PTR_ERR(trans); + ret = btrfs_commit_transaction(trans, root); + return ret; +} + +static int btrfs_show_options(struct seq_file *seq, struct vfsmount *vfs) +{ + struct btrfs_root *root = btrfs_sb(vfs->mnt_sb); + struct btrfs_fs_info *info = root->fs_info; + char *compress_type; + + if (btrfs_test_opt(root, DEGRADED)) + seq_puts(seq, ",degraded"); + if (btrfs_test_opt(root, NODATASUM)) + seq_puts(seq, ",nodatasum"); + if (btrfs_test_opt(root, NODATACOW)) + seq_puts(seq, ",nodatacow"); + if (btrfs_test_opt(root, NOBARRIER)) + seq_puts(seq, ",nobarrier"); + if (info->max_inline != 8192 * 1024) + seq_printf(seq, ",max_inline=%llu", + (unsigned long long)info->max_inline); + if (info->alloc_start != 0) + seq_printf(seq, ",alloc_start=%llu", + (unsigned long long)info->alloc_start); + if (info->thread_pool_size != min_t(unsigned long, + num_online_cpus() + 2, 8)) + seq_printf(seq, ",thread_pool=%d", info->thread_pool_size); + if (btrfs_test_opt(root, COMPRESS)) { + if (info->compress_type == BTRFS_COMPRESS_ZLIB) + compress_type = "zlib"; + else + compress_type = "lzo"; + if (btrfs_test_opt(root, FORCE_COMPRESS)) + seq_printf(seq, ",compress-force=%s", compress_type); + else + seq_printf(seq, ",compress=%s", compress_type); + } + if (btrfs_test_opt(root, NOSSD)) + seq_puts(seq, ",nossd"); + if (btrfs_test_opt(root, SSD_SPREAD)) + seq_puts(seq, ",ssd_spread"); + else if (btrfs_test_opt(root, SSD)) + seq_puts(seq, ",ssd"); + if (btrfs_test_opt(root, NOTREELOG)) + seq_puts(seq, ",notreelog"); + if (btrfs_test_opt(root, FLUSHONCOMMIT)) + seq_puts(seq, ",flushoncommit"); + if (btrfs_test_opt(root, DISCARD)) + seq_puts(seq, ",discard"); + if (!(root->fs_info->sb->s_flags & MS_POSIXACL)) + seq_puts(seq, ",noacl"); + if (btrfs_test_opt(root, SPACE_CACHE)) + seq_puts(seq, ",space_cache"); + if (btrfs_test_opt(root, CLEAR_CACHE)) + seq_puts(seq, ",clear_cache"); + if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED)) + seq_puts(seq, ",user_subvol_rm_allowed"); + if (btrfs_test_opt(root, ENOSPC_DEBUG)) + seq_puts(seq, ",enospc_debug"); + if (btrfs_test_opt(root, AUTO_DEFRAG)) + seq_puts(seq, ",autodefrag"); + if (btrfs_test_opt(root, INODE_MAP_CACHE)) + seq_puts(seq, ",inode_cache"); + return 0; +} + +static int btrfs_test_super(struct super_block *s, void *data) +{ + struct btrfs_root *test_root = data; + struct btrfs_root *root = btrfs_sb(s); + + /* + * If this super block is going away, return false as it + * can't match as an existing super block. + */ + if (!atomic_read(&s->s_active)) + return 0; + return root->fs_info->fs_devices == test_root->fs_info->fs_devices; +} + +static int btrfs_set_super(struct super_block *s, void *data) +{ + s->s_fs_info = data; + + return set_anon_super(s, data); +} + + +/* + * Find a superblock for the given device / mount point. + * + * Note: This is based on get_sb_bdev from fs/super.c with a few additions + * for multiple device setup. Make sure to keep it in sync. + */ +static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags, + const char *device_name, void *data) +{ + struct block_device *bdev = NULL; + struct super_block *s; + struct dentry *root; + struct btrfs_fs_devices *fs_devices = NULL; + struct btrfs_root *tree_root = NULL; + struct btrfs_fs_info *fs_info = NULL; + fmode_t mode = FMODE_READ; + char *subvol_name = NULL; + u64 subvol_objectid = 0; + u64 subvol_rootid = 0; + int error = 0; + + if (!(flags & MS_RDONLY)) + mode |= FMODE_WRITE; + + error = btrfs_parse_early_options(data, mode, fs_type, + &subvol_name, &subvol_objectid, + &subvol_rootid, &fs_devices); + if (error) + return ERR_PTR(error); + + error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices); + if (error) + goto error_free_subvol_name; + + error = btrfs_open_devices(fs_devices, mode, fs_type); + if (error) + goto error_free_subvol_name; + + if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) { + error = -EACCES; + goto error_close_devices; + } + + /* + * Setup a dummy root and fs_info for test/set super. This is because + * we don't actually fill this stuff out until open_ctree, but we need + * it for searching for existing supers, so this lets us do that and + * then open_ctree will properly initialize everything later. + */ + fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS); + tree_root = kzalloc(sizeof(struct btrfs_root), GFP_NOFS); + if (!fs_info || !tree_root) { + error = -ENOMEM; + goto error_close_devices; + } + fs_info->tree_root = tree_root; + fs_info->fs_devices = fs_devices; + tree_root->fs_info = fs_info; + + bdev = fs_devices->latest_bdev; + s = sget(fs_type, btrfs_test_super, btrfs_set_super, tree_root); + if (IS_ERR(s)) + goto error_s; + + if (s->s_root) { + if ((flags ^ s->s_flags) & MS_RDONLY) { + deactivate_locked_super(s); + error = -EBUSY; + goto error_close_devices; + } + + btrfs_close_devices(fs_devices); + kfree(fs_info); + kfree(tree_root); + } else { + char b[BDEVNAME_SIZE]; + + s->s_flags = flags | MS_NOSEC; + strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id)); + error = btrfs_fill_super(s, fs_devices, data, + flags & MS_SILENT ? 1 : 0); + if (error) { + deactivate_locked_super(s); + goto error_free_subvol_name; + } + + btrfs_sb(s)->fs_info->bdev_holder = fs_type; + s->s_flags |= MS_ACTIVE; + } + + /* if they gave us a subvolume name bind mount into that */ + if (strcmp(subvol_name, ".")) { + struct dentry *new_root; + + root = get_default_root(s, subvol_rootid); + if (IS_ERR(root)) { + error = PTR_ERR(root); + deactivate_locked_super(s); + goto error_free_subvol_name; + } + + mutex_lock(&root->d_inode->i_mutex); + new_root = lookup_one_len(subvol_name, root, + strlen(subvol_name)); + mutex_unlock(&root->d_inode->i_mutex); + + if (IS_ERR(new_root)) { + dput(root); + deactivate_locked_super(s); + error = PTR_ERR(new_root); + goto error_free_subvol_name; + } + if (!new_root->d_inode) { + dput(root); + dput(new_root); + deactivate_locked_super(s); + error = -ENXIO; + goto error_free_subvol_name; + } + dput(root); + root = new_root; + } else { + root = get_default_root(s, subvol_objectid); + if (IS_ERR(root)) { + error = PTR_ERR(root); + deactivate_locked_super(s); + goto error_free_subvol_name; + } + } + + kfree(subvol_name); + return root; + +error_s: + error = PTR_ERR(s); +error_close_devices: + btrfs_close_devices(fs_devices); + kfree(fs_info); + kfree(tree_root); +error_free_subvol_name: + kfree(subvol_name); + return ERR_PTR(error); +} + +static int btrfs_remount(struct super_block *sb, int *flags, char *data) +{ + struct btrfs_root *root = btrfs_sb(sb); + int ret; + + ret = btrfs_parse_options(root, data); + if (ret) + return -EINVAL; + + if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) + return 0; + + if (*flags & MS_RDONLY) { + sb->s_flags |= MS_RDONLY; + + ret = btrfs_commit_super(root); + WARN_ON(ret); + } else { + if (root->fs_info->fs_devices->rw_devices == 0) + return -EACCES; + + if (btrfs_super_log_root(&root->fs_info->super_copy) != 0) + return -EINVAL; + + ret = btrfs_cleanup_fs_roots(root->fs_info); + WARN_ON(ret); + + /* recover relocation */ + ret = btrfs_recover_relocation(root); + WARN_ON(ret); + + sb->s_flags &= ~MS_RDONLY; + } + + return 0; +} + +/* Used to sort the devices by max_avail(descending sort) */ +static int btrfs_cmp_device_free_bytes(const void *dev_info1, + const void *dev_info2) +{ + if (((struct btrfs_device_info *)dev_info1)->max_avail > + ((struct btrfs_device_info *)dev_info2)->max_avail) + return -1; + else if (((struct btrfs_device_info *)dev_info1)->max_avail < + ((struct btrfs_device_info *)dev_info2)->max_avail) + return 1; + else + return 0; +} + +/* + * sort the devices by max_avail, in which max free extent size of each device + * is stored.(Descending Sort) + */ +static inline void btrfs_descending_sort_devices( + struct btrfs_device_info *devices, + size_t nr_devices) +{ + sort(devices, nr_devices, sizeof(struct btrfs_device_info), + btrfs_cmp_device_free_bytes, NULL); +} + +/* + * The helper to calc the free space on the devices that can be used to store + * file data. + */ +static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes) +{ + struct btrfs_fs_info *fs_info = root->fs_info; + struct btrfs_device_info *devices_info; + struct btrfs_fs_devices *fs_devices = fs_info->fs_devices; + struct btrfs_device *device; + u64 skip_space; + u64 type; + u64 avail_space; + u64 used_space; + u64 min_stripe_size; + int min_stripes = 1; + int i = 0, nr_devices; + int ret; + + nr_devices = fs_info->fs_devices->rw_devices; + BUG_ON(!nr_devices); + + devices_info = kmalloc(sizeof(*devices_info) * nr_devices, + GFP_NOFS); + if (!devices_info) + return -ENOMEM; + + /* calc min stripe number for data space alloction */ + type = btrfs_get_alloc_profile(root, 1); + if (type & BTRFS_BLOCK_GROUP_RAID0) + min_stripes = 2; + else if (type & BTRFS_BLOCK_GROUP_RAID1) + min_stripes = 2; + else if (type & BTRFS_BLOCK_GROUP_RAID10) + min_stripes = 4; + + if (type & BTRFS_BLOCK_GROUP_DUP) + min_stripe_size = 2 * BTRFS_STRIPE_LEN; + else + min_stripe_size = BTRFS_STRIPE_LEN; + + list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) { + if (!device->in_fs_metadata) + continue; + + avail_space = device->total_bytes - device->bytes_used; + + /* align with stripe_len */ + do_div(avail_space, BTRFS_STRIPE_LEN); + avail_space *= BTRFS_STRIPE_LEN; + + /* + * In order to avoid overwritting the superblock on the drive, + * btrfs starts at an offset of at least 1MB when doing chunk + * allocation. + */ + skip_space = 1024 * 1024; + + /* user can set the offset in fs_info->alloc_start. */ + if (fs_info->alloc_start + BTRFS_STRIPE_LEN <= + device->total_bytes) + skip_space = max(fs_info->alloc_start, skip_space); + + /* + * btrfs can not use the free space in [0, skip_space - 1], + * we must subtract it from the total. In order to implement + * it, we account the used space in this range first. + */ + ret = btrfs_account_dev_extents_size(device, 0, skip_space - 1, + &used_space); + if (ret) { + kfree(devices_info); + return ret; + } + + /* calc the free space in [0, skip_space - 1] */ + skip_space -= used_space; + + /* + * we can use the free space in [0, skip_space - 1], subtract + * it from the total. + */ + if (avail_space && avail_space >= skip_space) + avail_space -= skip_space; + else + avail_space = 0; + + if (avail_space < min_stripe_size) + continue; + + devices_info[i].dev = device; + devices_info[i].max_avail = avail_space; + + i++; + } + + nr_devices = i; + + btrfs_descending_sort_devices(devices_info, nr_devices); + + i = nr_devices - 1; + avail_space = 0; + while (nr_devices >= min_stripes) { + if (devices_info[i].max_avail >= min_stripe_size) { + int j; + u64 alloc_size; + + avail_space += devices_info[i].max_avail * min_stripes; + alloc_size = devices_info[i].max_avail; + for (j = i + 1 - min_stripes; j <= i; j++) + devices_info[j].max_avail -= alloc_size; + } + i--; + nr_devices--; + } + + kfree(devices_info); + *free_bytes = avail_space; + return 0; +} + +static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf) +{ + struct btrfs_root *root = btrfs_sb(dentry->d_sb); + struct btrfs_super_block *disk_super = &root->fs_info->super_copy; + struct list_head *head = &root->fs_info->space_info; + struct btrfs_space_info *found; + u64 total_used = 0; + u64 total_free_data = 0; + int bits = dentry->d_sb->s_blocksize_bits; + __be32 *fsid = (__be32 *)root->fs_info->fsid; + int ret; + + /* holding chunk_muext to avoid allocating new chunks */ + mutex_lock(&root->fs_info->chunk_mutex); + rcu_read_lock(); + list_for_each_entry_rcu(found, head, list) { + if (found->flags & BTRFS_BLOCK_GROUP_DATA) { + total_free_data += found->disk_total - found->disk_used; + total_free_data -= + btrfs_account_ro_block_groups_free_space(found); + } + + total_used += found->disk_used; + } + rcu_read_unlock(); + + buf->f_namelen = BTRFS_NAME_LEN; + buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits; + buf->f_bfree = buf->f_blocks - (total_used >> bits); + buf->f_bsize = dentry->d_sb->s_blocksize; + buf->f_type = BTRFS_SUPER_MAGIC; + buf->f_bavail = total_free_data; + ret = btrfs_calc_avail_data_space(root, &total_free_data); + if (ret) { + mutex_unlock(&root->fs_info->chunk_mutex); + return ret; + } + buf->f_bavail += total_free_data; + buf->f_bavail = buf->f_bavail >> bits; + mutex_unlock(&root->fs_info->chunk_mutex); + + /* We treat it as constant endianness (it doesn't matter _which_) + because we want the fsid to come out the same whether mounted + on a big-endian or little-endian host */ + buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]); + buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]); + /* Mask in the root object ID too, to disambiguate subvols */ + buf->f_fsid.val[0] ^= BTRFS_I(dentry->d_inode)->root->objectid >> 32; + buf->f_fsid.val[1] ^= BTRFS_I(dentry->d_inode)->root->objectid; + + return 0; +} + +static struct file_system_type btrfs_fs_type = { + .owner = THIS_MODULE, + .name = "btrfs", + .mount = btrfs_mount, + .kill_sb = kill_anon_super, + .fs_flags = FS_REQUIRES_DEV, +}; + +/* + * used by btrfsctl to scan devices when no FS is mounted + */ +static long btrfs_control_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + struct btrfs_ioctl_vol_args *vol; + struct btrfs_fs_devices *fs_devices; + int ret = -ENOTTY; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + vol = memdup_user((void __user *)arg, sizeof(*vol)); + if (IS_ERR(vol)) + return PTR_ERR(vol); + + switch (cmd) { + case BTRFS_IOC_SCAN_DEV: + ret = btrfs_scan_one_device(vol->name, FMODE_READ, + &btrfs_fs_type, &fs_devices); + break; + } + + kfree(vol); + return ret; +} + +static int btrfs_freeze(struct super_block *sb) +{ + struct btrfs_root *root = btrfs_sb(sb); + mutex_lock(&root->fs_info->transaction_kthread_mutex); + mutex_lock(&root->fs_info->cleaner_mutex); + return 0; +} + +static int btrfs_unfreeze(struct super_block *sb) +{ + struct btrfs_root *root = btrfs_sb(sb); + mutex_unlock(&root->fs_info->cleaner_mutex); + mutex_unlock(&root->fs_info->transaction_kthread_mutex); + return 0; +} + +static const struct super_operations btrfs_super_ops = { + .drop_inode = btrfs_drop_inode, + .evict_inode = btrfs_evict_inode, + .put_super = btrfs_put_super, + .sync_fs = btrfs_sync_fs, + .show_options = btrfs_show_options, + .write_inode = btrfs_write_inode, + .dirty_inode = btrfs_dirty_inode, + .alloc_inode = btrfs_alloc_inode, + .destroy_inode = btrfs_destroy_inode, + .statfs = btrfs_statfs, + .remount_fs = btrfs_remount, + .freeze_fs = btrfs_freeze, + .unfreeze_fs = btrfs_unfreeze, +}; + +static const struct file_operations btrfs_ctl_fops = { + .unlocked_ioctl = btrfs_control_ioctl, + .compat_ioctl = btrfs_control_ioctl, + .owner = THIS_MODULE, + .llseek = noop_llseek, +}; + +static struct miscdevice btrfs_misc = { + .minor = BTRFS_MINOR, + .name = "btrfs-control", + .fops = &btrfs_ctl_fops +}; + +MODULE_ALIAS_MISCDEV(BTRFS_MINOR); +MODULE_ALIAS("devname:btrfs-control"); + +static int btrfs_interface_init(void) +{ + return misc_register(&btrfs_misc); +} + +static void btrfs_interface_exit(void) +{ + if (misc_deregister(&btrfs_misc) < 0) + printk(KERN_INFO "misc_deregister failed for control device"); +} + +static int __init init_btrfs_fs(void) +{ + int err; + + err = btrfs_init_sysfs(); + if (err) + return err; + + err = btrfs_init_compress(); + if (err) + goto free_sysfs; + + err = btrfs_init_cachep(); + if (err) + goto free_compress; + + err = extent_io_init(); + if (err) + goto free_cachep; + + err = extent_map_init(); + if (err) + goto free_extent_io; + + err = btrfs_delayed_inode_init(); + if (err) + goto free_extent_map; + + err = btrfs_interface_init(); + if (err) + goto free_delayed_inode; + + err = register_filesystem(&btrfs_fs_type); + if (err) + goto unregister_ioctl; + + printk(KERN_INFO "%s loaded\n", BTRFS_BUILD_VERSION); + return 0; + +unregister_ioctl: + btrfs_interface_exit(); +free_delayed_inode: + btrfs_delayed_inode_exit(); +free_extent_map: + extent_map_exit(); +free_extent_io: + extent_io_exit(); +free_cachep: + btrfs_destroy_cachep(); +free_compress: + btrfs_exit_compress(); +free_sysfs: + btrfs_exit_sysfs(); + return err; +} + +static void __exit exit_btrfs_fs(void) +{ + btrfs_destroy_cachep(); + btrfs_delayed_inode_exit(); + extent_map_exit(); + extent_io_exit(); + btrfs_interface_exit(); + unregister_filesystem(&btrfs_fs_type); + btrfs_exit_sysfs(); + btrfs_cleanup_fs_uuids(); + btrfs_exit_compress(); +} + +module_init(init_btrfs_fs) +module_exit(exit_btrfs_fs) + +MODULE_LICENSE("GPL"); |