fixes for 4.19

[thirdparty/kernel/stable-queue.git] / releases / 3.0.1 / dm-snapshot-flush-disk-cache-when-merging.patch

From 762a80d9fc9f690a3a35983f3b4619a220650808 Mon Sep 17 00:00:00 2001
From: Mikulas Patocka <mpatocka@redhat.com>
Date: Tue, 2 Aug 2011 12:32:00 +0100
Subject: dm snapshot: flush disk cache when merging

From: Mikulas Patocka <mpatocka@redhat.com>

commit 762a80d9fc9f690a3a35983f3b4619a220650808 upstream.

This patch makes dm-snapshot flush disk cache when writing metadata for
merging snapshot.

Without cache flushing the disk may reorder metadata write and other
data writes and there is a possibility of data corruption in case of
power fault.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 drivers/md/dm-snap-persistent.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/md/dm-snap-persistent.c
+++ b/drivers/md/dm-snap-persistent.c
@@ -753,7 +753,7 @@ static int persistent_commit_merge(struc
 	for (i = 0; i < nr_merged; i++)
 		clear_exception(ps, ps->current_committed - 1 - i);
 
-	r = area_io(ps, WRITE);
+	r = area_io(ps, WRITE_FLUSH_FUA);
 	if (r < 0)
 		return r;