dm-raid: add a new helper prepare_suspend() in md_personality

There are no functional changes for now, prepare to fix a deadlock for
dm-raid456.

Cc: stable@vger.kernel.org # v6.7+
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Xiao Ni <xni@redhat.com>
Acked-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20240305072306.2562024-8-yukuai1@huaweicloud.com

diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index 47c4b1b6e532a6e8c049eabbed6c930cdc013949..7d48943acd57cff286782e2f494a15240bae497d 100644 (file)
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -3803,6 +3803,23 @@ static void raid_io_hints(struct dm_target *ti, struct queue_limits *limits)
        blk_limits_io_opt(limits, chunk_size_bytes * mddev_data_stripes(rs));
 }
 
+static void raid_presuspend(struct dm_target *ti)
+{
+       struct raid_set *rs = ti->private;
+       struct mddev *mddev = &rs->md;
+
+       if (!reshape_interrupted(mddev))
+               return;
+
+       /*
+        * For raid456, if reshape is interrupted, IO across reshape position
+        * will never make progress, while caller will wait for IO to be done.
+        * Inform raid456 to handle those IO to prevent deadlock.
+        */
+       if (mddev->pers && mddev->pers->prepare_suspend)
+               mddev->pers->prepare_suspend(mddev);
+}
+
 static void raid_postsuspend(struct dm_target *ti)
 {
        struct raid_set *rs = ti->private;
@@ -4087,6 +4104,7 @@ static struct target_type raid_target = {
        .message = raid_message,
        .iterate_devices = raid_iterate_devices,
        .io_hints = raid_io_hints,
+       .presuspend = raid_presuspend,
        .postsuspend = raid_postsuspend,
        .preresume = raid_preresume,
        .resume = raid_resume,

diff --git a/drivers/md/md.h b/drivers/md/md.h
index d5721bd77f63b6071937caab079141f09df8598a..8041df038b5e9eab80757fdaf77aa126679aeb5d 100644 (file)
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -659,6 +659,7 @@ struct md_personality
        int (*start_reshape) (struct mddev *mddev);
        void (*finish_reshape) (struct mddev *mddev);
        void (*update_reshape_pos) (struct mddev *mddev);
+       void (*prepare_suspend) (struct mddev *mddev);
        /* quiesce suspends or resumes internal processing.
         * 1 - stop new actions and wait for action io to complete
         * 0 - return to normal behaviour