dm cache: fix writethrough mode quiescing in cache_map

Commit 2ee57d58735 ("dm cache: add passthrough mode") inadvertently
removed the deferred set reference that was taken in cache_map()'s
writethrough mode support.  Restore taking this reference.

This issue was found with code inspection.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
Cc: stable@vger.kernel.org # 3.13+

diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index 1bf4a71..9380be7 100644 (file)
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -2488,6 +2488,7 @@ static int cache_map(struct dm_target *ti, struct bio *bio)
 
                } else {
                        inc_hit_counter(cache, bio);
+                       pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds);
 
                        if (bio_data_dir(bio) == WRITE && writethrough_mode(&cache->features) &&
                            !is_dirty(cache, lookup_result.cblock))