dm: hold suspend_lock while suspending device during device deletion

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>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index e705042a997ceb85989e60cf38bdbbccfd5aab73..bd7c5c810214f7eec4c27f400ac2076f4da0b6f9 100644 (file)
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -2405,10 +2405,16 @@ static void __dm_destroy(struct mapped_device *md, bool wait)
        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);
 
        /* dm_put_live_table must be before msleep, otherwise deadlock is possible */
        dm_put_live_table(md, srcu_idx);