From bf5e74204e5d40545cc97a9a79d340b1615003a4 Mon Sep 17 00:00:00 2001 From: Lu Fengqi Date: Sun, 24 Apr 2016 13:33:47 +0800 Subject: [PATCH] btrfs-progs: check: introduce function to check shared data backref 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 Reviewed-by: Josef Bacik Signed-off-by: David Sterba --- cmds-check.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) diff --git a/cmds-check.c b/cmds-check.c index 3bf1b35..32e2e12 100644 --- a/cmds-check.c +++ b/cmds-check.c @@ -9177,6 +9177,50 @@ 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 REFERENCER_MISSING; + } + return 0; +} + static int btrfs_fsck_reinit_root(struct btrfs_trans_handle *trans, struct btrfs_root *root, int overwrite) { -- 2.7.4