btrfs: handle invalid root reference found in btrfs_init_root_free_objectid()

The btrfs_init_root_free_objectid() looks up a root by a key, allowing
to do an inexact search when key->offset is -1.  It's never expected to
find such item, as it would break the allowed range of a root id.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index d43b5d5df4b4ddfcde2e14557f22de3f04b4636d..b056b7d0e526804db922465e1b9467de6cf44c21 100644 (file)
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -4927,7 +4927,14 @@ int btrfs_init_root_free_objectid(struct btrfs_root *root)
        ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
        if (ret < 0)
                goto error;
-       BUG_ON(ret == 0); /* Corruption */
+       if (ret == 0) {
+               /*
+                * Key with offset -1 found, there would have to exist a root
+                * with such id, but this is out of valid range.
+                */
+               ret = -EUCLEAN;
+               goto error;
+       }
        if (path->slots[0] > 0) {
                slot = path->slots[0] - 1;
                l = path->nodes[0];