dm snapshot: flush disk cache when merging
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>
diff --git a/drivers/md/dm-snap-persistent.c b/drivers/md/dm-snap-persistent.c
index 135c2f1..e4ecadf 100644
--- a/drivers/md/dm-snap-persistent.c
+++ b/drivers/md/dm-snap-persistent.c
@@ -753,7 +753,7 @@
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;