Btrfs: check for NULL pointer in updating reloc roots

Add a check for NULL pointer to avoid invalid reference.

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 ba5a321..16e0c6f 100644 (file)
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -1269,6 +1269,8 @@ static int __update_reloc_root(struct btrfs_root *root, int del)
        }
        spin_unlock(&rc->reloc_root_tree.lock);
 
+       if (!node)
+               return 0;
        BUG_ON((struct btrfs_root *)node->data != root);
 
        if (!del) {