[PATCH] MD: move thread wakeups into resume

Patch name: md-move-thread-wakeups-into-resume.patch

Move personality and sync/recovery thread starting outside md_run.

Moving the wakeup's of the personality and sync/recovery threads out of
md_run and into do_md_run and mddev_resume solves two issues:
1) It allows bitmap_load to be called before the sync_thread is run and
2) when MD personalities are used by device-mapper (dm-raid.c), the start-up
of the array is better alligned with device-mapper primatives
(CTR/resume/suspend/DTR). I/O - in this case, recovery operations - should
not happen until after a resume has taken place.

RFC-by: Jonathan Brassow

Index: linux-2.6/drivers/md/md.c
============================================================ =======
--- linux-2.6.orig/drivers/md/md.c
+++ linux-2.6/drivers/md/md.c
@@ -351,6 +351,9 @@ void mddev_resume(mddev_t *mddev)
mddev->suspended = 0;
wake_up(&mddev->sb_wait);
mddev->pers->quiesce(mddev, 0);
+
+ md_wakeup_thread(mddev->thread);
+ md_wakeup_thread(mddev->sync_thread); /* possibly kick off a reshape */
}
EXPORT_SYMBOL_GPL(mddev_resume);

@@ -4948,9 +4951,6 @@ int md_run(mddev_t *mddev)
if (mddev->flags)
md_update_sb(mddev, 0);

- md_wakeup_thread(mddev->thread);
- md_wakeup_thread(mddev->sync_thread); /* possibly kick off a reshape */
-
md_new_event(mddev);
sysfs_notify_dirent_safe(mddev->sysfs_state);
sysfs_notify_dirent_safe(mddev->sysfs_action);
@@ -4971,6 +4971,10 @@ static int do_md_run(mddev_t *mddev)
bitmap_destroy(mddev);
goto out;
}
+
+ md_wakeup_thread(mddev->thread);
+ md_wakeup_thread(mddev->sync_thread); /* possibly kick off a reshape */
+
set_capacity(mddev->gendisk, mddev->array_sectors);
revalidate_disk(mddev->gendisk);
mddev->changed = 1;
--
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