dm: send empty barriers to targets in dm_flush
Pass empty barrier flushes to the targets in dm_flush().
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index edf9f24..36142e9 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -164,6 +164,9 @@
/* sysfs handle */
struct kobject kobj;
+
+ /* zero-length barrier that will be cloned and submitted to targets */
+ struct bio barrier_bio;
};
#define MIN_IOS 256
@@ -1477,6 +1480,13 @@
static void dm_flush(struct mapped_device *md)
{
dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE);
+
+ bio_init(&md->barrier_bio);
+ md->barrier_bio.bi_bdev = md->bdev;
+ md->barrier_bio.bi_rw = WRITE_BARRIER;
+ __split_and_process_bio(md, &md->barrier_bio);
+
+ dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE);
}
static void process_barrier(struct mapped_device *md, struct bio *bio)