md: unlock mddev before reap sync_thread in action_store

Since the bug which commit 8b48ec23cc51a ("md: don't unregister sync_thread
with reconfig_mutex held") fixed is related with action_store path, other
callers which reap sync_thread didn't need to be changed.

Let's pull md_unregister_thread from md_reap_sync_thread, then fix previous
bug with belows.

1. unlock mddev before md_reap_sync_thread in action_store.
2. save reshape_position before unlock, then restore it to ensure position
   not changed accidentally by others.

Signed-off-by: Guoqing Jiang <guoqing.jiang@linux.dev>
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index 1ec17c3..c640be4 100644 (file)
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -3728,6 +3728,7 @@ static int raid_message(struct dm_target *ti, unsigned int argc, char **argv,
        if (!strcasecmp(argv[0], "idle") || !strcasecmp(argv[0], "frozen")) {
                if (mddev->sync_thread) {
                        set_bit(MD_RECOVERY_INTR, &mddev->recovery);
+                       md_unregister_thread(&mddev->sync_thread);
                        md_reap_sync_thread(mddev);
                }
        } else if (decipher_sync_action(mddev, mddev->recovery) != st_idle)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index f511f18..7bc9671 100644 (file)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -4830,6 +4830,19 @@ action_store(struct mddev *mddev, const char *page, size_t len)
                        if (work_pending(&mddev->del_work))
                                flush_workqueue(md_misc_wq);
                        if (mddev->sync_thread) {
+                               sector_t save_rp = mddev->reshape_position;
+
+                               mddev_unlock(mddev);
+                               set_bit(MD_RECOVERY_INTR, &mddev->recovery);
+                               md_unregister_thread(&mddev->sync_thread);
+                               mddev_lock_nointr(mddev);
+                               /*
+                                * set RECOVERY_INTR again and restore reshape
+                                * position in case others changed them after
+                                * got lock, eg, reshape_position_store and
+                                * md_check_recovery.
+                                */
+                               mddev->reshape_position = save_rp;
                                set_bit(MD_RECOVERY_INTR, &mddev->recovery);
                                md_reap_sync_thread(mddev);
                        }
@@ -6197,6 +6210,7 @@ static void __md_stop_writes(struct mddev *mddev)
                flush_workqueue(md_misc_wq);
        if (mddev->sync_thread) {
                set_bit(MD_RECOVERY_INTR, &mddev->recovery);
+               md_unregister_thread(&mddev->sync_thread);
                md_reap_sync_thread(mddev);
        }
 
@@ -9309,6 +9323,7 @@ void md_check_recovery(struct mddev *mddev)
                         * ->spare_active and clear saved_raid_disk
                         */
                        set_bit(MD_RECOVERY_INTR, &mddev->recovery);
+                       md_unregister_thread(&mddev->sync_thread);
                        md_reap_sync_thread(mddev);
                        clear_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
                        clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
@@ -9344,6 +9359,7 @@ void md_check_recovery(struct mddev *mddev)
                        goto unlock;
                }
                if (mddev->sync_thread) {
+                       md_unregister_thread(&mddev->sync_thread);
                        md_reap_sync_thread(mddev);
                        goto unlock;
                }
@@ -9423,8 +9439,7 @@ void md_reap_sync_thread(struct mddev *mddev)
        sector_t old_dev_sectors = mddev->dev_sectors;
        bool is_reshaped = false;
 
-       /* resync has finished, collect result */
-       md_unregister_thread(&mddev->sync_thread);
+       /* sync_thread should be unregistered, collect result */
        if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery) &&
            !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
            mddev->degraded != mddev->raid_disks) {