Btrfs: return -ENOMEM in clear_extent_bit

The btrfs releasepage function depends on ENOMEM coming
back when it is called atomic.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index a90c4a12556b12bc432057fc1576fa209f19fbd5..0e0fe0f6ec751713979124fb175594ebc6e60308 100644 (file)
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -485,7 +485,8 @@ int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
 again:
        if (!prealloc && (mask & __GFP_WAIT)) {
                prealloc = alloc_extent_state(mask);
-               BUG_ON(!prealloc);
+               if (!prealloc)
+                       return -ENOMEM;
        }
 
        spin_lock(&tree->lock);