Btrfs: Fix PAGE_CACHE_SHIFT shifts on 32 bit machines

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

1 files changed, 1 insertions, 1 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 5a7e60d7f443..8935eec31ee2 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -159,7 +159,7 @@ static int csum_tree_block(struct btrfs_root *root, struct extent_buffer *buf,
 int csum_dirty_buffer(struct btrfs_root *root, struct page *page)
 {
         struct extent_map_tree *tree;
-        u64 start = page->index << PAGE_CACHE_SHIFT;
+        u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
         u64 found_start;
         int found_level;
         unsigned long len;