Btrfs: don't panic if we're trying to drop too many refs

This is just obnoxious.  Just print a message, abort the transaction, and return
an error.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>

1 files changed, 7 insertions, 1 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 6526f1faf6c2..f8a5652b0c43 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -5596,7 +5596,13 @@ static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
         }
 
         refs = btrfs_extent_refs(leaf, ei);
-        BUG_ON(refs < refs_to_drop);
+        if (refs < refs_to_drop) {
+                btrfs_err(info, "trying to drop %d refs but we only have %Lu "
+                          "for bytenr %Lu\n", refs_to_drop, refs, bytenr);
+                ret = -EINVAL;
+                btrfs_abort_transaction(trans, extent_root, ret);
+                goto out;
+        }
         refs -= refs_to_drop;
 
         if (refs > 0) {