diff options
Diffstat (limited to 'fs/btrfs/export.c')
| -rw-r--r-- | fs/btrfs/export.c | 133 |
1 files changed, 85 insertions, 48 deletions
diff --git a/fs/btrfs/export.c b/fs/btrfs/export.c index 9596b40..ba5c3fd 100644 --- a/fs/btrfs/export.c +++ b/fs/btrfs/export.c @@ -28,7 +28,7 @@ static int btrfs_encode_fh(struct dentry *dentry, u32 *fh, int *max_len, len = BTRFS_FID_SIZE_NON_CONNECTABLE; type = FILEID_BTRFS_WITHOUT_PARENT; - fid->objectid = BTRFS_I(inode)->location.objectid; + fid->objectid = inode->i_ino; fid->root_objectid = BTRFS_I(inode)->root->objectid; fid->gen = inode->i_generation; @@ -60,34 +60,61 @@ static int btrfs_encode_fh(struct dentry *dentry, u32 *fh, int *max_len, } static struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid, - u64 root_objectid, u32 generation) + u64 root_objectid, u32 generation, + int check_generation) { + struct btrfs_fs_info *fs_info = btrfs_sb(sb)->fs_info; struct btrfs_root *root; + struct dentry *dentry; struct inode *inode; struct btrfs_key key; + int index; + int err = 0; + + if (objectid < BTRFS_FIRST_FREE_OBJECTID) + return ERR_PTR(-ESTALE); key.objectid = root_objectid; btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY); key.offset = (u64)-1; - root = btrfs_read_fs_root_no_name(btrfs_sb(sb)->fs_info, &key); - if (IS_ERR(root)) - return ERR_CAST(root); + index = srcu_read_lock(&fs_info->subvol_srcu); + + root = btrfs_read_fs_root_no_name(fs_info, &key); + if (IS_ERR(root)) { + err = PTR_ERR(root); + goto fail; + } + + if (btrfs_root_refs(&root->root_item) == 0) { + err = -ENOENT; + goto fail; + } key.objectid = objectid; btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY); key.offset = 0; inode = btrfs_iget(sb, &key, root); - if (IS_ERR(inode)) - return (void *)inode; + if (IS_ERR(inode)) { + err = PTR_ERR(inode); + goto fail; + } + + srcu_read_unlock(&fs_info->subvol_srcu, index); - if (generation != inode->i_generation) { + if (check_generation && generation != inode->i_generation) { iput(inode); return ERR_PTR(-ESTALE); } - return d_obtain_alias(inode); + dentry = d_obtain_alias(inode); + if (!IS_ERR(dentry)) + dentry->d_op = &btrfs_dentry_operations; + return dentry; +fail: + srcu_read_unlock(&fs_info->subvol_srcu, index); + return ERR_PTR(err); } static struct dentry *btrfs_fh_to_parent(struct super_block *sb, struct fid *fh, @@ -111,7 +138,7 @@ static struct dentry *btrfs_fh_to_parent(struct super_block *sb, struct fid *fh, objectid = fid->parent_objectid; generation = fid->parent_gen; - return btrfs_get_dentry(sb, objectid, root_objectid, generation); + return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1); } static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh, @@ -133,66 +160,76 @@ static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh, root_objectid = fid->root_objectid; generation = fid->gen; - return btrfs_get_dentry(sb, objectid, root_objectid, generation); + return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1); } static struct dentry *btrfs_get_parent(struct dentry *child) { struct inode *dir = child->d_inode; + static struct dentry *dentry; struct btrfs_root *root = BTRFS_I(dir)->root; - struct btrfs_key key; struct btrfs_path *path; struct extent_buffer *leaf; - int slot; - u64 objectid; + struct btrfs_root_ref *ref; + struct btrfs_key key; + struct btrfs_key found_key; int ret; path = btrfs_alloc_path(); - key.objectid = dir->i_ino; - btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY); - key.offset = (u64)-1; + if (dir->i_ino == BTRFS_FIRST_FREE_OBJECTID) { + key.objectid = root->root_key.objectid; + key.type = BTRFS_ROOT_BACKREF_KEY; + key.offset = (u64)-1; + root = root->fs_info->tree_root; + } else { + key.objectid = dir->i_ino; + key.type = BTRFS_INODE_REF_KEY; + key.offset = (u64)-1; + } ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); - if (ret < 0) { - /* Error */ - btrfs_free_path(path); - return ERR_PTR(ret); + if (ret < 0) + goto fail; + + BUG_ON(ret == 0); + if (path->slots[0] == 0) { + ret = -ENOENT; + goto fail; } + + path->slots[0]--; leaf = path->nodes[0]; - slot = path->slots[0]; - if (ret) { - /* btrfs_search_slot() returns the slot where we'd want to - insert a backref for parent inode #0xFFFFFFFFFFFFFFFF. - The _real_ backref, telling us what the parent inode - _actually_ is, will be in the slot _before_ the one - that btrfs_search_slot() returns. */ - if (!slot) { - /* Unless there is _no_ key in the tree before... */ - btrfs_free_path(path); - return ERR_PTR(-EIO); - } - slot--; + + btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]); + if (found_key.objectid != key.objectid || found_key.type != key.type) { + ret = -ENOENT; + goto fail; } - btrfs_item_key_to_cpu(leaf, &key, slot); + if (found_key.type == BTRFS_ROOT_BACKREF_KEY) { + ref = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_root_ref); + key.objectid = btrfs_root_ref_dirid(leaf, ref); + } else { + key.objectid = found_key.offset; + } btrfs_free_path(path); - if (key.objectid != dir->i_ino || key.type != BTRFS_INODE_REF_KEY) - return ERR_PTR(-EINVAL); - - objectid = key.offset; - - /* If we are already at the root of a subvol, return the real root */ - if (objectid == dir->i_ino) - return dget(dir->i_sb->s_root); + if (found_key.type == BTRFS_ROOT_BACKREF_KEY) { + return btrfs_get_dentry(root->fs_info->sb, key.objectid, + found_key.offset, 0, 0); + } - /* Build a new key for the inode item */ - key.objectid = objectid; - btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY); + key.type = BTRFS_INODE_ITEM_KEY; key.offset = 0; - - return d_obtain_alias(btrfs_iget(root->fs_info->sb, &key, root)); + dentry = d_obtain_alias(btrfs_iget(root->fs_info->sb, &key, root)); + if (!IS_ERR(dentry)) + dentry->d_op = &btrfs_dentry_operations; + return dentry; +fail: + btrfs_free_path(path); + return ERR_PTR(ret); } const struct export_operations btrfs_export_ops = { |