Btrfs: Add back file data checksumming

Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 3878772..5accced 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -594,6 +594,7 @@
 	tree_root->nodesize = nodesize;
 	tree_root->leafsize = leafsize;
 	tree_root->sectorsize = sectorsize;
+	sb_set_blocksize(sb, sectorsize);
 
 	i_size_write(fs_info->btree_inode,
 		     btrfs_super_total_bytes(disk_super));