From patchwork Fri Nov 17 14:48:30 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Filipe Manana X-Patchwork-Id: 10073969 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id AB82D6037F for ; Fri, 24 Nov 2017 11:31:16 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 947E32A3CA for ; Fri, 24 Nov 2017 11:31:16 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 89A782A3D1; Fri, 24 Nov 2017 11:31:16 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.5 required=2.0 tests=BAYES_00, DATE_IN_PAST_96_XX, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D5F912A3CF for ; Fri, 24 Nov 2017 11:31:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753431AbdKXLbN (ORCPT ); Fri, 24 Nov 2017 06:31:13 -0500 Received: from mail.kernel.org ([198.145.29.99]:50126 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753239AbdKXLbM (ORCPT ); Fri, 24 Nov 2017 06:31:12 -0500 Received: from debian3.lan (bl12-226-64.dsl.telepac.pt [85.245.226.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A9C9121996 for ; Fri, 24 Nov 2017 11:31:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A9C9121996 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=fdmanana@kernel.org From: fdmanana@kernel.org To: linux-btrfs@vger.kernel.org Subject: [PATCH] Btrfs: incremental send, fix wrong unlink path after renaming file Date: Fri, 17 Nov 2017 14:48:30 +0000 Message-Id: <20171117144830.17839-1-fdmanana@kernel.org> X-Mailer: git-send-email 2.11.0 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Filipe Manana Under some circumstances, an incremental send operation can issue wrong paths for unlink commands related to files that have multiple hard links and some (or all) of those links were renamed between the parent and send snapshots. Consider the following example: Parent snapshot . (ino 256) |---- a/ (ino 257) | |---- b/ (ino 259) | | |---- c/ (ino 260) | | |---- f2 (ino 261) | | | |---- f2l1 (ino 261) | |---- d/ (ino 262) |---- f1l1_2 (ino 258) |---- f2l2 (ino 261) |---- f1_2 (ino 258) Send snapshot . (ino 256) |---- a/ (ino 257) | |---- f2l1/ (ino 263) | |---- b2/ (ino 259) | |---- c/ (ino 260) | | |---- d3 (ino 262) | | |---- f1l1_2 (ino 258) | | |---- f2l2_2 (ino 261) | | |---- f1_2 (ino 258) | | | |---- f2 (ino 261) | |---- f1l2 (ino 258) | |---- d (ino 261) When computing the incremental send stream the following steps happen: 1) When processing inode 261, a rename operation is issued that renames inode 262, which currently as a path of "d", to an orphan name of "o262-7-0". This is done because in the send snapshot, inode 261 has of its hard links with a path of "d" as well. 2) Two link operations are issued that create the new hard links for inode 261, whose names are "d" and "f2l2_2", at paths "/" and "o262-7-0/" respectively. 3) Still while processing inode 261, unlink operations are issued to remove the old hard links of inode 261, with names "f2l1" and "f2l2", at paths "a/" and "d/". However path "d/" does not correspond anymore to the directory inode 262 but corresponds instead to a hard link of inode 261 (link command issued in the previous step). This makes the receiver fail with a ENOTDIR error when attempting the unlink operation. The problem happens because before sending the unlink operation, we failed to detect that inode 262 was one of ancestors for inode 261 in the parent snapshot, and therefore we didn't recompute the path for inode 262 before issuing the unlink operation for the link named "f2l2" of inode 262. The detection failed because the function "is_ancestor()" only follows the first hard link it finds for an inode instead of all of its hard links (as it was originally created for being used with directories only, for which only one hard link exists). So fix this by making "is_ancestor()" follow all hard links of the input inode. A test case for fstests follows soon. Signed-off-by: Filipe Manana --- fs/btrfs/send.c | 124 ++++++++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 106 insertions(+), 18 deletions(-) diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c index 8fd195cfe81b..2c35717a3470 100644 --- a/fs/btrfs/send.c +++ b/fs/btrfs/send.c @@ -3527,7 +3527,40 @@ static int wait_for_dest_dir_move(struct send_ctx *sctx, } /* - * Check if ino ino1 is an ancestor of inode ino2 in the given root. + * Check if inode ino2, or any of its ancestors, is inode ino1. + * Return 1 if true, 0 if false and < 0 on error. + */ +static int check_ino_in_path(struct btrfs_root *root, + const u64 ino1, + const u64 ino1_gen, + const u64 ino2, + const u64 ino2_gen, + struct fs_path *fs_path) +{ + u64 ino = ino2; + + if (ino1 == ino2) + return ino1_gen == ino2_gen; + + while (ino > BTRFS_FIRST_FREE_OBJECTID) { + u64 parent; + u64 parent_gen; + int ret; + + fs_path_reset(fs_path); + ret = get_first_ref(root, ino, &parent, &parent_gen, fs_path); + if (ret < 0) + return ret; + if (parent == ino1) + return parent_gen == ino1_gen; + ino = parent; + } + return 0; +} + +/* + * Check if ino ino1 is an ancestor of inode ino2 in the given root for any + * possible path (in case ino2 is not a directory and has multiple hard links). * Return 1 if true, 0 if false and < 0 on error. */ static int is_ancestor(struct btrfs_root *root, @@ -3536,36 +3569,91 @@ static int is_ancestor(struct btrfs_root *root, const u64 ino2, struct fs_path *fs_path) { - u64 ino = ino2; - bool free_path = false; + bool free_fs_path = false; int ret = 0; + struct btrfs_path *path = NULL; + struct btrfs_key key; if (!fs_path) { fs_path = fs_path_alloc(); if (!fs_path) return -ENOMEM; - free_path = true; + free_fs_path = true; } - while (ino > BTRFS_FIRST_FREE_OBJECTID) { - u64 parent; - u64 parent_gen; + path = alloc_path_for_send(); + if (!path) { + ret = -ENOMEM; + goto out; + } - fs_path_reset(fs_path); - ret = get_first_ref(root, ino, &parent, &parent_gen, fs_path); - if (ret < 0) { - if (ret == -ENOENT && ino == ino2) - ret = 0; - goto out; + key.objectid = ino2; + key.type = BTRFS_INODE_REF_KEY; + key.offset = 0; + + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); + if (ret < 0) + goto out; + + while (true) { + struct extent_buffer *leaf = path->nodes[0]; + int slot = path->slots[0]; + u32 cur_offset = 0; + u32 item_size; + + if (slot >= btrfs_header_nritems(leaf)) { + ret = btrfs_next_leaf(root, path); + if (ret < 0) + goto out; + if (ret > 0) + break; + continue; } - if (parent == ino1) { - ret = parent_gen == ino1_gen ? 1 : 0; - goto out; + + btrfs_item_key_to_cpu(leaf, &key, slot); + if (key.objectid != ino2) + break; + if (key.type != BTRFS_INODE_REF_KEY && + key.type != BTRFS_INODE_EXTREF_KEY) + break; + + item_size = btrfs_item_size_nr(leaf, slot); + while (cur_offset < item_size) { + u64 parent; + u64 parent_gen; + + if (key.type == BTRFS_INODE_EXTREF_KEY) { + unsigned long ptr; + struct btrfs_inode_extref *extref; + + ptr = btrfs_item_ptr_offset(leaf, slot); + extref = (struct btrfs_inode_extref *) + (ptr + cur_offset); + parent = btrfs_inode_extref_parent(leaf, + extref); + cur_offset += sizeof(*extref); + cur_offset += btrfs_inode_extref_name_len(leaf, + extref); + } else { + parent = key.offset; + cur_offset = item_size; + } + + ret = get_inode_info(root, parent, NULL, &parent_gen, + NULL, NULL, NULL, NULL); + if (ret < 0) + goto out; + ret = check_ino_in_path(root, ino1, ino1_gen, + parent, parent_gen, fs_path); + if (ret) + goto out; } - ino = parent; + path->slots[0]++; } + ret = 0; out: - if (free_path) + btrfs_free_path(path); + if (free_fs_path) fs_path_free(fs_path); return ret; }