From patchwork Tue Apr 26 03:48:53 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qu Wenruo X-Patchwork-Id: 8934671 Return-Path: X-Original-To: patchwork-linux-btrfs@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id BA22B9F372 for ; Tue, 26 Apr 2016 03:50:31 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id C9B102015A for ; Tue, 26 Apr 2016 03:50:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CDBA420120 for ; Tue, 26 Apr 2016 03:50:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752189AbcDZDuY (ORCPT ); Mon, 25 Apr 2016 23:50:24 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:39542 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751964AbcDZDtj (ORCPT ); Mon, 25 Apr 2016 23:49:39 -0400 X-IronPort-AV: E=Sophos;i="5.20,367,1444665600"; d="scan'208";a="455029" Received: from unknown (HELO cn.fujitsu.com) ([10.167.250.3]) by song.cn.fujitsu.com with ESMTP; 26 Apr 2016 11:49:09 +0800 Received: from adam-work.localdomain (unknown [10.167.226.34]) by cn.fujitsu.com (Postfix) with ESMTP id 8348E4056409; Tue, 26 Apr 2016 11:49:04 +0800 (CST) From: Qu Wenruo To: linux-btrfs@vger.kernel.org Cc: dsterba@suse.cz, Lu Fengqi Subject: [PATCH RFC 06/16] btrfs-progs: fsck: Introduce function to check referencer for data backref Date: Tue, 26 Apr 2016 11:48:53 +0800 Message-Id: <1461642543-4621-7-git-send-email-quwenruo@cn.fujitsu.com> X-Mailer: git-send-email 2.8.0 In-Reply-To: <1461642543-4621-1-git-send-email-quwenruo@cn.fujitsu.com> References: <1461642543-4621-1-git-send-email-quwenruo@cn.fujitsu.com> MIME-Version: 1.0 X-yoursite-MailScanner-ID: 8348E4056409.A95D6 X-yoursite-MailScanner: Found to be clean X-yoursite-MailScanner-From: quwenruo@cn.fujitsu.com X-Spam-Status: No, score=-7.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Lu Fengqi Introduce new function check_extent_data_backref() to search referencer for a given data backref. Signed-off-by: Lu Fengqi Signed-off-by: Qu Wenruo Reviewed-by: Josef Bacik --- cmds-check.c | 96 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 96 insertions(+) diff --git a/cmds-check.c b/cmds-check.c index 1d1b198..8f971b9 100644 --- a/cmds-check.c +++ b/cmds-check.c @@ -8873,6 +8873,102 @@ out: return 0; } +/* + * Check referencer for normal(inlined) data ref + * If len == 0, it will be resolved by searching in extent tree + */ +static int check_extent_data_backref(struct btrfs_fs_info *fs_info, + u64 root_id, u64 objectid, u64 offset, + u64 bytenr, u64 len) +{ + struct btrfs_root *root; + struct btrfs_root *extent_root = fs_info->extent_root; + struct btrfs_key key; + struct btrfs_path path; + struct extent_buffer *leaf; + struct btrfs_file_extent_item *fi; + int slot; + int found_referencer = 0; + int ret = 0; + + if (!len) { + key.objectid = bytenr; + key.type = BTRFS_EXTENT_ITEM_KEY; + key.offset = (u64)-1; + + btrfs_init_path(&path); + ret = btrfs_search_slot(NULL, extent_root, &key, &path, 0, 0); + if (ret < 0) + goto out; + ret = btrfs_previous_extent_item(extent_root, &path, bytenr); + if (ret) + goto out; + btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]); + if (key.objectid != bytenr || + key.type != BTRFS_EXTENT_ITEM_KEY) + goto out; + len = key.offset; + btrfs_release_path(&path); + } + key.objectid = root_id; + btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY); + key.offset = (u64)-1; + + root = btrfs_read_fs_root(fs_info, &key); + if (IS_ERR(root)) + goto out; + + btrfs_init_path(&path); + key.objectid = objectid; + key.type = BTRFS_EXTENT_DATA_KEY; + /* + * It can be nasty as data backref offset is + * file offset - file extent offset, which is smaller or + * equal to original backref offset. + * The only special case is overflow. + * So we need to special judgement and do further search + */ + key.offset = offset & (1ULL << 63) ? 0 : offset; + + ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0); + if (ret < 0) + goto out; + + /* Search afterwards to get correct one */ + while (1) { + leaf = path.nodes[0]; + slot = path.slots[0]; + + btrfs_item_key_to_cpu(leaf, &key, slot); + if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY) + break; + fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item); + /* + * Except normal disk bytenr and disk num bytes, we still + * need to do extra check on dbackref offset as + * dbackref offset = file_offset - file_extent_offset + */ + if (btrfs_file_extent_disk_bytenr(leaf, fi) == bytenr && + btrfs_file_extent_disk_num_bytes(leaf, fi) == len && + (u64)(key.offset - btrfs_file_extent_offset(leaf, fi)) == + offset) { + found_referencer = 1; + break; + } + ret = btrfs_next_item(root, &path); + if (ret) + break; + } +out: + btrfs_release_path(&path); + if (!found_referencer) { + error("Extent[%llu, %llu] lost referencer(root: %llu, owner: %llu, offset: %llu)", + bytenr, len, root_id, objectid, offset); + return -MISSING_REFERENCER; + } + return 0; +} + static int btrfs_fsck_reinit_root(struct btrfs_trans_handle *trans, struct btrfs_root *root, int overwrite) {