dm-raid456, md/raid456: fix a deadlock for dm-raid456 while io concurrent with reshape

[linux-2.6-microblaze.git] / drivers / md / dm-raid.c

diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index 7d48943..ea45f77 100644 (file)
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -213,6 +213,7 @@ struct raid_dev {
 #define RT_FLAG_RS_IN_SYNC             6
 #define RT_FLAG_RS_RESYNCING           7
 #define RT_FLAG_RS_GROW                        8
+#define RT_FLAG_RS_FROZEN              9
 
 /* Array elements of 64 bit needed for rebuild/failed disk bits */
 #define DISKS_ARRAY_ELEMS ((MAX_RAID_DEVICES + (sizeof(uint64_t) * 8 - 1)) / sizeof(uint64_t) / 8)
@@ -3340,7 +3341,8 @@ static int raid_map(struct dm_target *ti, struct bio *bio)
        if (unlikely(bio_end_sector(bio) > mddev->array_sectors))
                return DM_MAPIO_REQUEUE;
 
-       md_handle_request(mddev, bio);
+       if (unlikely(!md_handle_request(mddev, bio)))
+               return DM_MAPIO_REQUEUE;
 
        return DM_MAPIO_SUBMITTED;
 }
@@ -3724,7 +3726,8 @@ static int raid_message(struct dm_target *ti, unsigned int argc, char **argv,
        if (!mddev->pers || !mddev->pers->sync_request)
                return -EINVAL;
 
-       if (test_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags))
+       if (test_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags) ||
+           test_bit(RT_FLAG_RS_FROZEN, &rs->runtime_flags))
                return -EBUSY;
 
        if (!strcasecmp(argv[0], "frozen")) {
@@ -3808,6 +3811,12 @@ static void raid_presuspend(struct dm_target *ti)
        struct raid_set *rs = ti->private;
        struct mddev *mddev = &rs->md;
 
+       /*
+        * From now on, disallow raid_message() to change sync_thread until
+        * resume, raid_postsuspend() is too late.
+        */
+       set_bit(RT_FLAG_RS_FROZEN, &rs->runtime_flags);
+
        if (!reshape_interrupted(mddev))
                return;
 
@@ -3820,6 +3829,13 @@ static void raid_presuspend(struct dm_target *ti)
                mddev->pers->prepare_suspend(mddev);
 }
 
+static void raid_presuspend_undo(struct dm_target *ti)
+{
+       struct raid_set *rs = ti->private;
+
+       clear_bit(RT_FLAG_RS_FROZEN, &rs->runtime_flags);
+}
+
 static void raid_postsuspend(struct dm_target *ti)
 {
        struct raid_set *rs = ti->private;
@@ -4085,6 +4101,7 @@ static void raid_resume(struct dm_target *ti)
 
                WARN_ON_ONCE(!test_bit(MD_RECOVERY_FROZEN, &mddev->recovery));
                WARN_ON_ONCE(test_bit(MD_RECOVERY_RUNNING, &mddev->recovery));
+               clear_bit(RT_FLAG_RS_FROZEN, &rs->runtime_flags);
                mddev_lock_nointr(mddev);
                mddev->ro = 0;
                mddev->in_sync = 0;
@@ -4105,6 +4122,7 @@ static struct target_type raid_target = {
        .iterate_devices = raid_iterate_devices,
        .io_hints = raid_io_hints,
        .presuspend = raid_presuspend,
+       .presuspend_undo = raid_presuspend_undo,
        .postsuspend = raid_postsuspend,
        .preresume = raid_preresume,
        .resume = raid_resume,