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authorMikulas Patocka <mpatocka@redhat.com>2009-06-22 05:12:25 -0400
committerAlasdair G Kergon <agk@redhat.com>2009-06-22 05:12:25 -0400
commit494b3ee7d4f69210def80aecce28d08c3f0755d5 (patch)
tree8cd8fc4de72cf9a1a56e45518019a3cae106515a /drivers/md/dm-snap.c
parent8627921fa2ef6d40fd9b787e163ba3a9ff8f471d (diff)
dm snapshot: support barriers
Flush support for dm-snapshot target. This patch just forwards the flush request to either the origin or the snapshot device. (It doesn't flush exception store metadata.) Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'drivers/md/dm-snap.c')
-rw-r--r--drivers/md/dm-snap.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index d73f17fc7778..d573165cd2b7 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -678,6 +678,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
678 678
679 ti->private = s; 679 ti->private = s;
680 ti->split_io = s->store->chunk_size; 680 ti->split_io = s->store->chunk_size;
681 ti->num_flush_requests = 1;
681 682
682 return 0; 683 return 0;
683 684
@@ -1030,6 +1031,11 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio,
1030 chunk_t chunk; 1031 chunk_t chunk;
1031 struct dm_snap_pending_exception *pe = NULL; 1032 struct dm_snap_pending_exception *pe = NULL;
1032 1033
1034 if (unlikely(bio_empty_barrier(bio))) {
1035 bio->bi_bdev = s->store->cow->bdev;
1036 return DM_MAPIO_REMAPPED;
1037 }
1038
1033 chunk = sector_to_chunk(s->store, bio->bi_sector); 1039 chunk = sector_to_chunk(s->store, bio->bi_sector);
1034 1040
1035 /* Full snapshots are not usable */ 1041 /* Full snapshots are not usable */
@@ -1338,6 +1344,8 @@ static int origin_ctr(struct dm_target *ti, unsigned int argc, char **argv)
1338 } 1344 }
1339 1345
1340 ti->private = dev; 1346 ti->private = dev;
1347 ti->num_flush_requests = 1;
1348
1341 return 0; 1349 return 0;
1342} 1350}
1343 1351
@@ -1353,6 +1361,9 @@ static int origin_map(struct dm_target *ti, struct bio *bio,
1353 struct dm_dev *dev = ti->private; 1361 struct dm_dev *dev = ti->private;
1354 bio->bi_bdev = dev->bdev; 1362 bio->bi_bdev = dev->bdev;
1355 1363
1364 if (unlikely(bio_empty_barrier(bio)))
1365 return DM_MAPIO_REMAPPED;
1366
1356 /* Only tell snapshots if this is a write */ 1367 /* Only tell snapshots if this is a write */
1357 return (bio_rw(bio) == WRITE) ? do_origin(dev, bio) : DM_MAPIO_REMAPPED; 1368 return (bio_rw(bio) == WRITE) ? do_origin(dev, bio) : DM_MAPIO_REMAPPED;
1358} 1369}