From 968d8b0627d3585d6b82da4239b9adf98614ab7c Mon Sep 17 00:00:00 2001
From: "Denis V. Lunev" <den@openvz.org>
Date: Thu, 16 Jun 2016 19:09:40 +0300
Subject: [PATCH] block: fix race in bdrv_co_discard with drive-mirror
Actually we must set dirty bitmap dirty after we have written all our
zeroes for correct processing in drive mirror code. In the other case
we can face not zeroes in this area in mirror_iteration.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Vladimir Sementsov-Ogievskiy<vsementsov@virtuozzo.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 1466093381-6120-3-git-send-email-den@openvz.org
CC: Stefan Hajnoczi <stefanha@redhat.com>
CC: Kevin Wolf <kwolf@redhat.com>
CC: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
block/io.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/block/io.c b/block/io.c
index 3527d91aa0..8ab6f95477 100644
--- a/block/io.c
+++ b/block/io.c
@@ -2349,7 +2349,6 @@ int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num,
tracked_request_begin(&req, bs, sector_num << BDRV_SECTOR_BITS,
nb_sectors << BDRV_SECTOR_BITS, BDRV_TRACKED_DISCARD);
- bdrv_set_dirty(bs, sector_num, nb_sectors);
max_discard = MIN_NON_ZERO(bs->bl.max_discard, BDRV_REQUEST_MAX_SECTORS);
while (nb_sectors > 0) {
@@ -2398,6 +2397,8 @@ int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num,
}
ret = 0;
out:
+ bdrv_set_dirty(bs, req.offset >> BDRV_SECTOR_BITS,
+ req.bytes >> BDRV_SECTOR_BITS);
tracked_request_end(&req);
return ret;
}
--
2.30.2