dm snapshot: use barrier when writing exception store

Send barrier requests when updating the exception area.

Exception area updates need to be ordered w.r.t. data writes, so that
the writes are not reordered in hardware disk cache.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This commit is contained in:
Mikulas Patocka 2009-06-22 10:12:26 +01:00 committed by Alasdair G Kergon
parent 51aa322849
commit 2bd0234525

View file

@ -636,7 +636,7 @@ static void persistent_commit_exception(struct dm_exception_store *store,
/*
* Commit exceptions to disk.
*/
if (ps->valid && area_io(ps, WRITE))
if (ps->valid && area_io(ps, WRITE_BARRIER))
ps->valid = 0;
/*