md: fix deadlock in md/raid1 and md/raid10 when handling a read error

[linux-2.6-omap-h63xx.git] / drivers / md / raid10.c

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 017f58113c33604e381a5fcc7c75f01344f67841..5de42d87bf4ed23d17a8762609140f01c536779b 100644 (file)
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -629,7 +629,36 @@ static int raid10_congested(void *data, int bits)
        return ret;
 }
 
-
+static int flush_pending_writes(conf_t *conf)
+{
+       /* Any writes that have been queued but are awaiting
+        * bitmap updates get flushed here.
+        * We return 1 if any requests were actually submitted.
+        */
+       int rv = 0;
+
+       spin_lock_irq(&conf->device_lock);
+
+       if (conf->pending_bio_list.head) {
+               struct bio *bio;
+               bio = bio_list_get(&conf->pending_bio_list);
+               blk_remove_plug(conf->mddev->queue);
+               spin_unlock_irq(&conf->device_lock);
+               /* flush any pending bitmap writes to disk
+                * before proceeding w/ I/O */
+               bitmap_unplug(conf->mddev->bitmap);
+
+               while (bio) { /* submit pending writes */
+                       struct bio *next = bio->bi_next;
+                       bio->bi_next = NULL;
+                       generic_make_request(bio);
+                       bio = next;
+               }
+               rv = 1;
+       } else
+               spin_unlock_irq(&conf->device_lock);
+       return rv;
+}
 /* Barriers....
  * Sometimes we need to suspend IO while we do something else,
  * either some resync/recovery, or reconfigure the array.
@@ -720,7 +749,8 @@ static void freeze_array(conf_t *conf)
        wait_event_lock_irq(conf->wait_barrier,
                            conf->barrier+conf->nr_pending == conf->nr_queued+2,
                            conf->resync_lock,
-                           raid10_unplug(conf->mddev->queue));
+                           ({ flush_pending_writes(conf);
+                              raid10_unplug(conf->mddev->queue); }));
        spin_unlock_irq(&conf->resync_lock);
 }
 
@@ -892,6 +922,9 @@ static int make_request(struct request_queue *q, struct bio * bio)
        blk_plug_device(mddev->queue);
        spin_unlock_irqrestore(&conf->device_lock, flags);
 
+       /* In case raid10d snuck in to freeze_array */
+       wake_up(&conf->wait_barrier);
+
        if (do_sync)
                md_wakeup_thread(mddev->thread);
 
@@ -1464,28 +1497,14 @@ static void raid10d(mddev_t *mddev)
 
        for (;;) {
                char b[BDEVNAME_SIZE];
-               spin_lock_irqsave(&conf->device_lock, flags);
 
-               if (conf->pending_bio_list.head) {
-                       bio = bio_list_get(&conf->pending_bio_list);
-                       blk_remove_plug(mddev->queue);
-                       spin_unlock_irqrestore(&conf->device_lock, flags);
-                       /* flush any pending bitmap writes to disk before proceeding w/ I/O */
-                       bitmap_unplug(mddev->bitmap);
+               unplug += flush_pending_writes(conf);
 
-                       while (bio) { /* submit pending writes */
-                               struct bio *next = bio->bi_next;
-                               bio->bi_next = NULL;
-                               generic_make_request(bio);
-                               bio = next;
-                       }
-                       unplug = 1;
-
-                       continue;
-               }
-
-               if (list_empty(head))
+               spin_lock_irqsave(&conf->device_lock, flags);
+               if (list_empty(head)) {
+                       spin_unlock_irqrestore(&conf->device_lock, flags);
                        break;
+               }
                r10_bio = list_entry(head->prev, r10bio_t, retry_list);
                list_del(head->prev);
                conf->nr_queued--;
@@ -1548,7 +1567,6 @@ static void raid10d(mddev_t *mddev)
                        }
                }
        }
-       spin_unlock_irqrestore(&conf->device_lock, flags);
        if (unplug)
                unplug_slaves(mddev);
 }