Btrfs: do not BUG_ON in prepare_to_reloc

We can bail out from here gracefully instead of a cold BUG_ON.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 7d1654cf9d485c873fa547b3819c9060b6e4795f..9d13786eec73628715d23395693e71908c3d9e92 100644 (file)
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -3731,7 +3731,15 @@ int prepare_to_relocate(struct reloc_control *rc)
        set_reloc_control(rc);
 
        trans = btrfs_join_transaction(rc->extent_root);
-       BUG_ON(IS_ERR(trans));
+       if (IS_ERR(trans)) {
+               unset_reloc_control(rc);
+               /*
+                * extent tree is not a ref_cow tree and has no reloc_root to
+                * cleanup.  And callers are responsible to free the above
+                * block rsv.
+                */
+               return PTR_ERR(trans);
+       }
        btrfs_commit_transaction(trans, rc->extent_root);
        return 0;
 }