dm: linear support flush

Flush support for the linear target.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c
index 79fb53e51c70..ecbb17421da4 100644
--- a/drivers/md/dm-linear.c
+++ b/drivers/md/dm-linear.c
@@ -53,6 +53,7 @@ static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv)
                 goto bad;
         }
 
+        ti->num_flush_requests = 1;
         ti->private = lc;
         return 0;
 
@@ -81,7 +82,8 @@ static void linear_map_bio(struct dm_target *ti, struct bio *bio)
         struct linear_c *lc = ti->private;
 
         bio->bi_bdev = lc->dev->bdev;
-        bio->bi_sector = linear_map_sector(ti, bio->bi_sector);
+        if (bio_sectors(bio))
+                bio->bi_sector = linear_map_sector(ti, bio->bi_sector);
 }
 
 static int linear_map(struct dm_target *ti, struct bio *bio,