dm-snapshot-flush.patch
Flush support for dm-snapshot target.
This patch just forwars the flush request to origin and snapshot device,
it doesn't flush exception store metadata.
Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
---
drivers/md/dm-snap.c | 11 +++++++++++
1 file changed, 11 insertions(+)
Index: linux-2.6.30-rc1-devel/drivers/md/dm-snap.c
===================================================================
--- linux-2.6.30-rc1-devel.orig/drivers/md/dm-snap.c 2009-04-10 06:24:53.000000000 +0200
+++ linux-2.6.30-rc1-devel/drivers/md/dm-snap.c 2009-04-10 06:33:48.000000000 +0200
@@ -678,6 +678,7 @@ static int snapshot_ctr(struct dm_target
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
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->private = dev;
+ ti->num_flush_requests = 1;
+
return 0;
}
@@ -1353,6 +1361,9 @@ static int origin_map(struct dm_target *
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;
}
--
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