From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cn.fujitsu.com ([222.73.24.84]:53791 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752145AbcDZDtq (ORCPT ); Mon, 25 Apr 2016 23:49:46 -0400 From: Qu Wenruo To: linux-btrfs@vger.kernel.org Cc: dsterba@suse.cz, Lu Fengqi Subject: [PATCH RFC 07/16] btrfs-progs: fsck: Introduce function to check shared data backref Date: Tue, 26 Apr 2016 11:48:54 +0800 Message-Id: <1461642543-4621-8-git-send-email-quwenruo@cn.fujitsu.com> 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 Sender: linux-btrfs-owner@vger.kernel.org List-ID: From: Lu Fengqi Introduce the function check_shared_data_backref() to check the referencer of a given shared data backref. Signed-off-by: Lu Fengqi Signed-off-by: Qu Wenruo --- cmds-check.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) diff --git a/cmds-check.c b/cmds-check.c index 8f971b9..5588898 100644 --- a/cmds-check.c +++ b/cmds-check.c @@ -8969,6 +8969,50 @@ out: return 0; } +/* + * Check if the referencer of a shared data backref exists + */ +static int check_shared_data_backref(struct btrfs_fs_info *fs_info, + u64 parent, u64 bytenr) +{ + struct extent_buffer *eb; + struct btrfs_key key; + struct btrfs_file_extent_item *fi; + u32 nodesize = btrfs_super_nodesize(fs_info->super_copy); + u32 nr; + int found_parent = 0; + int i; + + eb = read_tree_block_fs_info(fs_info, parent, nodesize, 0); + if (!extent_buffer_uptodate(eb)) + goto out; + + nr = btrfs_header_nritems(eb); + for (i = 0; i < nr; i++) { + btrfs_item_key_to_cpu(eb, &key, i); + if (key.type != BTRFS_EXTENT_DATA_KEY) + continue; + + fi = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item); + if (btrfs_file_extent_type(eb, fi) == BTRFS_FILE_EXTENT_INLINE) + continue; + + if (btrfs_file_extent_disk_bytenr(eb, fi) == bytenr) { + found_parent = 1; + break; + } + } + +out: + free_extent_buffer(eb); + if (!found_parent) { + error("Shared extent %llu referencer lost(parent: %llu)", + bytenr, parent); + return -MISSING_REFERENCER; + } + return 0; +} + static int btrfs_fsck_reinit_root(struct btrfs_trans_handle *trans, struct btrfs_root *root, int overwrite) { -- 2.8.0