3.16.83-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Liu Bo <bo.li.liu@xxxxxxxxxx> commit 02794222c4132ac003e7281fb71f4ec1645ffc87 upstream. 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@xxxxxxxxxx> Signed-off-by: David Sterba <dsterba@xxxxxxxx> Signed-off-by: Ben Hutchings <ben.hutchings@xxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx> --- fs/btrfs/extent-tree.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -2258,7 +2258,13 @@ static int run_delayed_tree_ref(struct b 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,