[PATCH 3.2 100/221] dm: hold suspend_lock while suspending device during device deletion

Ben Hutchings
2015-05-05T01:36:02Z

From: Mikulas Patocka <mpatocka@redhat.com>

commit ab7c7bb6f4ab95dbca96fcfc4463cd69843e3e24 upstream.

__dm_destroy() must take the suspend_lock so that its presuspend and
postsuspend calls do not race with an internal suspend.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/md/dm.c | 6 ++++++
1 file changed, 6 insertions(+)

--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -2295,10 +2295,16 @@ static void __dm_destroy(struct mapped_d
set_bit(DMF_FREEING, &md->flags);
spin_unlock(&_minor_lock);

+ /*
+ * Take suspend_lock so that presuspend and postsuspend methods
+ * do not race with internal suspend.
+ */
+ mutex_lock(&md->suspend_lock);
if (!dm_suspended_md(md)) {
dm_table_presuspend_targets(map);
dm_table_postsuspend_targets(map);
}
+ mutex_unlock(&md->suspend_lock);

/*
* Rare, but there may be I/O requests still going to complete,