diff options
Diffstat (limited to 'fs/btrfs/super.c')
-rw-r--r-- | fs/btrfs/super.c | 172 |
1 files changed, 147 insertions, 25 deletions
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index f8b4521de90..f878337cee6 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -63,10 +63,10 @@ static void btrfs_put_super(struct super_block *sb) } enum { - Opt_degraded, Opt_subvol, Opt_device, Opt_nodatasum, Opt_nodatacow, - Opt_max_extent, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, - Opt_ssd, Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, - Opt_compress, Opt_compress_force, Opt_notreelog, Opt_ratio, + Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum, + Opt_nodatacow, Opt_max_extent, Opt_max_inline, Opt_alloc_start, + Opt_nobarrier, Opt_ssd, Opt_nossd, Opt_ssd_spread, Opt_thread_pool, + Opt_noacl, Opt_compress, Opt_compress_force, Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard, Opt_err, }; @@ -74,6 +74,7 @@ enum { 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"}, @@ -157,6 +158,7 @@ int btrfs_parse_options(struct btrfs_root *root, char *options) btrfs_set_opt(info->mount_opt, DEGRADED); break; case Opt_subvol: + case Opt_subvolid: case Opt_device: /* * These are parsed by btrfs_parse_early_options @@ -292,12 +294,13 @@ out: * 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, + void *holder, char **subvol_name, u64 *subvol_objectid, struct btrfs_fs_devices **fs_devices) { substring_t args[MAX_OPT_ARGS]; char *opts, *p; int error = 0; + int intarg; if (!options) goto out; @@ -320,6 +323,12 @@ static int btrfs_parse_early_options(const char *options, fmode_t flags, case Opt_subvol: *subvol_name = match_strdup(&args[0]); break; + case Opt_subvolid: + intarg = 0; + match_int(&args[0], &intarg); + if (intarg) + *subvol_objectid = intarg; + break; case Opt_device: error = btrfs_scan_one_device(match_strdup(&args[0]), flags, holder, fs_devices); @@ -347,6 +356,110 @@ static int btrfs_parse_early_options(const char *options, fmode_t flags, 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 (!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_PTR(PTR_ERR(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 (!inode) + return ERR_PTR(-ENOMEM); + + /* + * 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) @@ -380,7 +493,7 @@ static int btrfs_fill_super(struct super_block *sb, 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); + inode = btrfs_iget(sb, &key, tree_root->fs_info->fs_root, NULL); if (IS_ERR(inode)) { err = PTR_ERR(inode); goto fail_close; @@ -392,12 +505,6 @@ static int btrfs_fill_super(struct super_block *sb, err = -ENOMEM; goto fail_close; } -#if 0 - /* this does the super kobj at the same time */ - err = btrfs_sysfs_add_super(tree_root->fs_info); - if (err) - goto fail_close; -#endif sb->s_root = root_dentry; @@ -489,19 +596,22 @@ static int btrfs_test_super(struct super_block *s, void *data) static int btrfs_get_sb(struct file_system_type *fs_type, int flags, const char *dev_name, void *data, struct vfsmount *mnt) { - char *subvol_name = NULL; struct block_device *bdev = NULL; struct super_block *s; struct dentry *root; struct btrfs_fs_devices *fs_devices = NULL; fmode_t mode = FMODE_READ; + char *subvol_name = NULL; + u64 subvol_objectid = 0; int error = 0; + int found = 0; if (!(flags & MS_RDONLY)) mode |= FMODE_WRITE; error = btrfs_parse_early_options(data, mode, fs_type, - &subvol_name, &fs_devices); + &subvol_name, &subvol_objectid, + &fs_devices); if (error) return error; @@ -530,6 +640,7 @@ static int btrfs_get_sb(struct file_system_type *fs_type, int flags, goto error_close_devices; } + found = 1; btrfs_close_devices(fs_devices); } else { char b[BDEVNAME_SIZE]; @@ -547,25 +658,35 @@ static int btrfs_get_sb(struct file_system_type *fs_type, int flags, s->s_flags |= MS_ACTIVE; } - if (!strcmp(subvol_name, ".")) - root = dget(s->s_root); - else { - mutex_lock(&s->s_root->d_inode->i_mutex); - root = lookup_one_len(subvol_name, s->s_root, + root = get_default_root(s, subvol_objectid); + if (IS_ERR(root)) { + error = PTR_ERR(root); + deactivate_locked_super(s); + goto error; + } + /* if they gave us a subvolume name bind mount into that */ + if (strcmp(subvol_name, ".")) { + struct dentry *new_root; + mutex_lock(&root->d_inode->i_mutex); + new_root = lookup_one_len(subvol_name, root, strlen(subvol_name)); - mutex_unlock(&s->s_root->d_inode->i_mutex); + mutex_unlock(&root->d_inode->i_mutex); - if (IS_ERR(root)) { + if (IS_ERR(new_root)) { deactivate_locked_super(s); - error = PTR_ERR(root); - goto error_free_subvol_name; + error = PTR_ERR(new_root); + dput(root); + goto error_close_devices; } - if (!root->d_inode) { + if (!new_root->d_inode) { dput(root); + dput(new_root); deactivate_locked_super(s); error = -ENXIO; - goto error_free_subvol_name; + goto error_close_devices; } + dput(root); + root = new_root; } mnt->mnt_sb = s; @@ -580,6 +701,7 @@ error_close_devices: btrfs_close_devices(fs_devices); error_free_subvol_name: kfree(subvol_name); +error: return error; } |