Btrfs: 64 bit div fixes

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

1 files changed, 2 insertions, 1 deletions

diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index 0782e924ddeb..fb8c214160c1 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -239,7 +239,8 @@ int btrfs_csum_truncate(struct btrfs_trans_handle *trans,
         if (isize <= key.offset)
                 return 0;
         new_item_span = isize - key.offset;
-        blocks = (new_item_span + root->blocksize - 1) / root->blocksize;
+        blocks = (new_item_span + root->blocksize - 1) >>
+                root->fs_info->sb->s_blocksize_bits;
         new_item_size = blocks * BTRFS_CRC32_SIZE;
         if (new_item_size >= btrfs_item_size(leaf->items + slot))
                 return 0;