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| author | Mikulas Patocka <mpatocka@redhat.com> | 2009-06-22 13:12:25 +0400 |
|---|---|---|
| committer | Alasdair G Kergon <agk@redhat.com> | 2009-06-22 13:12:25 +0400 |
| commit | 494b3ee7d4f69210def80aecce28d08c3f0755d5 (patch) | |
| tree | 8cd8fc4de72cf9a1a56e45518019a3cae106515a | |
| parent | 8627921fa2ef6d40fd9b787e163ba3a9ff8f471d (diff) | |
| download | linux-494b3ee7d4f69210def80aecce28d08c3f0755d5.tar.xz | |
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>
| -rw-r--r-- | drivers/md/dm-snap.c | 11 |
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) ti->private = s; ti->split_io = s->store->chunk_size; + ti->num_flush_requests = 1; return 0; @@ -1030,6 +1031,11 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio, chunk_t chunk; struct dm_snap_pending_exception *pe = NULL; + if (unlikely(bio_empty_barrier(bio))) { + bio->bi_bdev = s->store->cow->bdev; + return DM_MAPIO_REMAPPED; + } + chunk = sector_to_chunk(s->store, bio->bi_sector); /* Full snapshots are not usable */ @@ -1338,6 +1344,8 @@ static int origin_ctr(struct dm_target *ti, unsigned int argc, char **argv) } ti->private = dev; + ti->num_flush_requests = 1; + return 0; } @@ -1353,6 +1361,9 @@ static int origin_map(struct dm_target *ti, struct bio *bio, struct dm_dev *dev = ti->private; bio->bi_bdev = dev->bdev; + if (unlikely(bio_empty_barrier(bio))) + return DM_MAPIO_REMAPPED; + /* Only tell snapshots if this is a write */ return (bio_rw(bio) == WRITE) ? do_origin(dev, bio) : DM_MAPIO_REMAPPED; } |