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authorMikulas Patocka <mpatocka@redhat.com>2012-07-20 14:25:07 +0100
committerAlasdair G Kergon <agk@redhat.com>2012-07-20 14:25:07 +0100
commit7c8d3a42fe1c58a7e8fd3f6a013e7d7b474ff931 (patch)
tree876e2084849a853ef55b2636b61408c4d138fea7
parent650d2a06b4fe1cc1d218c20e256650f68bf0ca31 (diff)
dm raid1: set discard_zeroes_data_unsupported
We can't guarantee that REQ_DISCARD on dm-mirror zeroes the data even if the underlying disks support zero on discard. So this patch sets ti->discard_zeroes_data_unsupported. For example, if the mirror is in the process of resynchronizing, it may happen that kcopyd reads a piece of data, then discard is sent on the same area and then kcopyd writes the piece of data to another leg. Consequently, the data is not zeroed. The flag was made available by commit 983c7db347db8ce2d8453fd1d89b7a4bb6920d56 (dm crypt: always disable discard_zeroes_data). Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Cc: stable@kernel.org Signed-off-by: Alasdair G Kergon <agk@redhat.com>
-rw-r--r--drivers/md/dm-raid1.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index ea16984c0f08..b58b7a33914a 100644
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -1084,6 +1084,7 @@ static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
ti->split_io = dm_rh_get_region_size(ms->rh);
ti->num_flush_requests = 1;
ti->num_discard_requests = 1;
+ ti->discard_zeroes_data_unsupported = 1;
ms->kmirrord_wq = alloc_workqueue("kmirrord",
WQ_NON_REENTRANT | WQ_MEM_RECLAIM, 0);