On Sat, Oct 31 2015, Nate Dailey wrote:
> I first tested 4.3-rc6 that I already had laying around, and verified that the
> bug still happens.
>
> Then I reverted 7eb418851f3278de67126ea0c427641ab4792c57, rebuilt & installed,
> and tested again. Reverting this patch did indeed fix the bug.
>
> Thank you!
>
> Nate
>
Thanks a lot for testing.
The following with go to Linus soon, hopefully in time for 4.3-final.
It should then be picked up by stable.
If anyone wants to try their hand at the "future patch" I mentioned, I
wouldn't object. MD_FEATURE_RECOVERY_BITMAP is an important part of the
picture. I won't have an opportunity to work on it until December.
Thanks,
NeilBrown
commit d01552a76d71f9879af448e9142389ee9be6e95b
Author: NeilBrown <neilb@xxxxxxxx>
Date: Sat Oct 31 11:00:56 2015 +1100
Revert "md: allow a partially recovered device to be hot-added to an array."
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>
Cc: stable@xxxxxxxxxxxxxxx (3.14+)
Fixes: 7eb418851f32 ("md: allow a partially recovered device to be hot-added to an array.")
diff --git a/drivers/md/md.c b/drivers/md/md.c
index c702de18207a..3fe3d04a968a 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -8040,8 +8040,7 @@ static int remove_and_add_spares(struct mddev *mddev,
!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))
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