btrfs-progs: Fix a bug in reset_nlink() which may deletes the recovered file

In reset_nlink(), we believe rec->found_link as accurate number of the
valid links. However it only records the number of found DIR_ITEM, so we
can't use it as reliable value.

Before this patch, in some case, leaf corruption recovery will believe
there is a valid backref but don't add_link() since it can't find any
valid one and don't put it into the lost+found dir.
So the recovered inode will be considered as an orphan item without
orphan item and repair_inode_orphan_item() will add orphan item for it,
causing all the filename/filetype we recovered being a waste of time.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>

diff --git a/cmds-check.c b/cmds-check.c
index 3e7a4eb..e74b116 100644 (file)
--- a/cmds-check.c
+++ b/cmds-check.c
@@ -1959,6 +1959,9 @@ static int reset_nlink(struct btrfs_trans_handle *trans,
        struct btrfs_inode_item *inode_item;
        int ret = 0;
 
+       /* We don't believe this either, reset it and iterate backref */
+       rec->found_link = 0;
+
        /* Remove all backref including the valid ones */
        list_for_each_entry_safe(backref, tmp, &rec->backrefs, list) {
                ret = btrfs_unlink(trans, root, rec->ino, backref->dir,
@@ -1973,6 +1976,8 @@ static int reset_nlink(struct btrfs_trans_handle *trans,
                      backref->found_inode_ref)) {
                        list_del(&backref->list);
                        free(backref);
+               } else {
+                       rec->found_link++;
                }
        }