[dm-devel] [PATCH for-dm-3.14-fixes 1/8] dm thin: synchronize the pool mode during suspend

[Mike Snitzer]

Commit b5330655 ("dm thin: handle metadata failures more consistently")
increased potential for the pool's mode to be changed in response to
metadata operation failures.

When the pool mode is changed it isn't synchronized with the mode in
pool_features stored in the target's context (ti->private) that is used
as the basis for (re)establishing the pool mode during resume via
bind_control_target.

It is important that we synchronize the pool mode when suspending
otherwise the pool may experience and unexpected mode transition on the
next resume (especially if there was no new table load).

Signed-off-by: Mike Snitzer <snitzer at redhat.com>
---
 drivers/md/dm-thin.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index d501e43..9facc6f 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -2364,6 +2364,12 @@ static void pool_postsuspend(struct dm_target *ti)
 	cancel_delayed_work(&pool->waker);
 	flush_workqueue(pool->wq);
 	(void) commit(pool);
+
+	/*
+	 * The pool mode may have changed, sync it so bind_control_target()
+	 * doesn't cause an unexpected mode transition on resume.
+	 */
+	pt->adjusted_pf.mode = get_pool_mode(pool);
 }
 
 static int check_arg_count(unsigned argc, unsigned args_required)
-- 
1.8.3.1