btrfs: fix compile when block cgroups are not enabled

bio->bi_css and bio->bi_ioc don't exist when block cgroups are not on.
This adds an ifdef around them.  It's not perfect, but our
use of bi_ioc is being removed in the 4.3 merge window.

The bi_css usage really should go into bio_clone, but I want to make
sure that doesn't introduce problems for other bio_clone use cases.

Signed-off-by: Chris Mason <clm@fb.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 3cfbd6261f9b..fa19f2f68c1b 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2730,9 +2730,12 @@ struct bio *btrfs_bio_clone(struct bio *bio, gfp_t gfp_mask)
                 btrfs_bio->csum = NULL;
                 btrfs_bio->csum_allocated = NULL;
                 btrfs_bio->end_io = NULL;
+
+#ifdef CONFIG_BLK_CGROUP
                 /* FIXME, put this into bio_clone_bioset */
                 if (bio->bi_css)
                         bio_associate_blkcg(new, bio->bi_css);
+#endif
         }
         return new;
 }