dm mpath: check if path's request_queue is dying in activate_path()

If pg_init_retries is set and a request is queued against a multipath
device with all underlying block device request_queues in the "dying"
state then an infinite loop is triggered because activate_path() never
succeeds and hence never calls pg_init_done().

This change avoids that device removal triggers an infinite loop by
failing the activate_path() which causes the "dying" path to be failed.

Reported-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index ac734e5..15db5e9 100644 (file)
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -1521,10 +1521,10 @@ static void activate_path(struct work_struct *work)
 {
        struct pgpath *pgpath =
                container_of(work, struct pgpath, activate_path.work);
+       struct request_queue *q = bdev_get_queue(pgpath->path.dev->bdev);
 
-       if (pgpath->is_active)
-               scsi_dh_activate(bdev_get_queue(pgpath->path.dev->bdev),
-                                pg_init_done, pgpath);
+       if (pgpath->is_active && !blk_queue_dying(q))
+               scsi_dh_activate(q, pg_init_done, pgpath);
        else
                pg_init_done(pgpath, SCSI_DH_DEV_OFFLINED);
 }