diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c index 4b6ce5cab444..a86fc723aad9 100644 --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -955,6 +955,8 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root *parent_root; struct btrfs_block_rsv *rsv; struct inode *parent_inode; + struct btrfs_path *path; + struct btrfs_dir_item *dir_item; struct dentry *parent; struct dentry *dentry; struct extent_buffer *tmp; @@ -967,6 +969,12 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans, u64 root_flags; uuid_le new_uuid; + path = btrfs_alloc_path(); + if (!path) { + ret = pending->error = -ENOMEM; + goto path_alloc_fail; + } + new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS); if (!new_root_item) { ret = pending->error = -ENOMEM; @@ -1015,23 +1023,20 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans, */ ret = btrfs_set_inode_index(parent_inode, &index); BUG_ON(ret); /* -ENOMEM */ - ret = btrfs_insert_dir_item(trans, parent_root, - dentry->d_name.name, dentry->d_name.len, - parent_inode, &key, - BTRFS_FT_DIR, index); - if (ret == -EEXIST) { + + /* check if there is a file/dir which has the same name. */ + dir_item = btrfs_lookup_dir_item(NULL, parent_root, path, + btrfs_ino(parent_inode), + dentry->d_name.name, + dentry->d_name.len, 0); + if (dir_item != NULL && !IS_ERR(dir_item)) { pending->error = -EEXIST; goto fail; - } else if (ret) { + } else if (IS_ERR(dir_item)) { + ret = PTR_ERR(dir_item); goto abort_trans; } - - btrfs_i_size_write(parent_inode, parent_inode->i_size + - dentry->d_name.len * 2); - parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME; - ret = btrfs_update_inode(trans, parent_root, parent_inode); - if (ret) - goto abort_trans; + btrfs_release_path(path); /* * pull in the delayed directory update @@ -1123,12 +1128,30 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans, ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1); if (ret) goto abort_trans; + + ret = btrfs_insert_dir_item(trans, parent_root, + dentry->d_name.name, dentry->d_name.len, + parent_inode, &key, + BTRFS_FT_DIR, index); + /* We have check then name at the beginning, so it is impossible. */ + BUG_ON(ret == -EEXIST); + if (ret) + goto abort_trans; + + btrfs_i_size_write(parent_inode, parent_inode->i_size + + dentry->d_name.len * 2); + parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME; + ret = btrfs_update_inode(trans, parent_root, parent_inode); + if (ret) + goto abort_trans; fail: dput(parent); trans->block_rsv = rsv; no_free_objectid: kfree(new_root_item); root_item_alloc_fail: + btrfs_free_path(path); +path_alloc_fail: btrfs_block_rsv_release(root, &pending->block_rsv, (u64)-1); return ret; @@ -1472,13 +1495,28 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans, */ mutex_lock(&root->fs_info->reloc_mutex); - ret = btrfs_run_delayed_items(trans, root); + /* + * We needn't worry about the delayed items because we will + * deal with them in create_pending_snapshot(), which is the + * core function of the snapshot creation. + */ + ret = create_pending_snapshots(trans, root->fs_info); if (ret) { mutex_unlock(&root->fs_info->reloc_mutex); goto cleanup_transaction; } - ret = create_pending_snapshots(trans, root->fs_info); + /* + * We insert the dir indexes of the snapshots and update the inode + * of the snapshots' parents after the snapshot creation, so there + * are some delayed items which are not dealt with. Now deal with + * them. + * + * We needn't worry that this operation will corrupt the snapshots, + * because all the tree which are snapshoted will be forced to COW + * the nodes and leaves. + */ + ret = btrfs_run_delayed_items(trans, root); if (ret) { mutex_unlock(&root->fs_info->reloc_mutex); goto cleanup_transaction;