From: Liu Bo <bo.li.liu@oracle.com>
Date: Thu, 15 Sep 2016 02:19:05 +0000 (-0700)
Subject: Btrfs: kill BUG_ON in run_delayed_tree_ref
X-Git-Tag: v4.9-rc1~46^2~16
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=02794222c4132ac003e7281fb71f4ec1645ffc87;p=linux.git

Btrfs: kill BUG_ON in run_delayed_tree_ref

In a corrupted btrfs image, we can come across this BUG_ON and
get an unreponsive system, but if we return errors instead,
its caller can handle everything gracefully by aborting the current
transaction.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 73fb91f9d797..3d3b193a396c 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2352,7 +2352,13 @@ static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
 		ins.type = BTRFS_EXTENT_ITEM_KEY;
 	}
 
-	BUG_ON(node->ref_mod != 1);
+	if (node->ref_mod != 1) {
+		btrfs_err(root->fs_info,
+	"btree block(%llu) has %d references rather than 1: action %d ref_root %llu parent %llu",
+			  node->bytenr, node->ref_mod, node->action, ref_root,
+			  parent);
+		return -EIO;
+	}
 	if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
 		BUG_ON(!extent_op || !extent_op->update_flags);
 		ret = alloc_reserved_tree_block(trans, root,