This is a note to let you know that I've just added the patch titled Revert "md: allow a partially recovered device to be hot-added to an array." to the 4.2-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: revert-md-allow-a-partially-recovered-device-to-be-hot-added-to-an-array.patch and it can be found in the queue-4.2 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From d01552a76d71f9879af448e9142389ee9be6e95b Mon Sep 17 00:00:00 2001 From: NeilBrown <neilb@xxxxxxxx> Date: Sat, 31 Oct 2015 11:00:56 +1100 Subject: Revert "md: allow a partially recovered device to be hot-added to an array." From: NeilBrown <neilb@xxxxxxxx> commit d01552a76d71f9879af448e9142389ee9be6e95b upstream. This reverts commit 7eb418851f3278de67126ea0c427641ab4792c57. This commit is poorly justified, I can find not discusison in email, and it clearly causes a problem. If a device which is being recovered fails and is subsequently re-added to an array, there could easily have been changes to the array *before* the point where the recovery was up to. So the recovery must start again from the beginning. If a spare is being recovered and fails, then when it is re-added we really should do a bitmap-based recovery up to the recovery-offset, and then a full recovery from there. Before this reversion, we only did the "full recovery from there" which is not corect. After this reversion with will do a full recovery from the start, which is safer but not ideal. It will be left to a future patch to arrange the two different styles of recovery. Reported-and-tested-by: Nate Dailey <nate.dailey@xxxxxxxxxxx> Signed-off-by: NeilBrown <neilb@xxxxxxxx> Fixes: 7eb418851f32 ("md: allow a partially recovered device to be hot-added to an array.") Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/md/md.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -8030,8 +8030,7 @@ static int remove_and_add_spares(struct !test_bit(Bitmap_sync, &rdev->flags))) continue; - if (rdev->saved_raid_disk < 0) - rdev->recovery_offset = 0; + rdev->recovery_offset = 0; if (mddev->pers-> hot_add_disk(mddev, rdev) == 0) { if (sysfs_link_rdev(mddev, rdev)) Patches currently in stable-queue which might be from neilb@xxxxxxxx are queue-4.2/revert-md-allow-a-partially-recovered-device-to-be-hot-added-to-an-array.patch queue-4.2/md-raid1-submit_bio_wait-returns-0-on-success.patch queue-4.2/md-raid10-submit_bio_wait-returns-0-on-success.patch queue-4.2/md-raid5-fix-locking-in-handle_stripe_clean_event.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html