Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 7acedc5b authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Alasdair G Kergon
Browse files

dm exception store: fix misordered writes 



We must zero the next chunk on disk *before* writing out the current chunk, not
after.  Otherwise if the machine crashes at the wrong time, the "end of metadata"
marker may be missing.

Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
Cc: stable@kernel.org
parent 7c9e6c17

drivers/md/dm-exception-store.c

+8 −3
Original line number Diff line number Diff line
@@ -610,18 +610,23 @@ static void persistent_commit(struct exception_store *store, 
	    (ps->current_committed != ps->exceptions_per_area))

		return;



	/*

	 * If we completely filled the current area, then wipe the next one.

	 */

	if ((ps->current_committed == ps->exceptions_per_area) &&

	     zero_disk_area(ps, ps->current_area + 1))

		ps->valid = 0;



	/*

	 * Commit exceptions to disk.

	 */

	if (area_io(ps, WRITE))

	if (ps->valid && area_io(ps, WRITE))

		ps->valid = 0;



	/*

	 * Advance to the next area if this one is full.

	 */

	if (ps->current_committed == ps->exceptions_per_area) {

		if (zero_disk_area(ps, ps->current_area + 1))

			ps->valid = 0;

		ps->current_committed = 0;

		ps->current_area++;

		zero_memory_area(ps);