| From 011abdc9df559ec75779bb7c53a744c69b2a94c6 Mon Sep 17 00:00:00 2001 |
| From: NeilBrown <neilb@suse.com> |
| Date: Thu, 26 Apr 2018 14:46:29 +1000 |
| Subject: md: fix two problems with setting the "re-add" device state. |
| |
| From: NeilBrown <neilb@suse.com> |
| |
| commit 011abdc9df559ec75779bb7c53a744c69b2a94c6 upstream. |
| |
| If "re-add" is written to the "state" file for a device |
| which is faulty, this has an effect similar to removing |
| and re-adding the device. It should take up the |
| same slot in the array that it previously had, and |
| an accelerated (e.g. bitmap-based) rebuild should happen. |
| |
| The slot that "it previously had" is determined by |
| rdev->saved_raid_disk. |
| However this is not set when a device fails (only when a device |
| is added), and it is cleared when resync completes. |
| This means that "re-add" will normally work once, but may not work a |
| second time. |
| |
| This patch includes two fixes. |
| 1/ when a device fails, record the ->raid_disk value in |
| ->saved_raid_disk before clearing ->raid_disk |
| 2/ when "re-add" is written to a device for which |
| ->saved_raid_disk is not set, fail. |
| |
| I think this is suitable for stable as it can |
| cause re-adding a device to be forced to do a full |
| resync which takes a lot longer and so puts data at |
| more risk. |
| |
| Cc: <stable@vger.kernel.org> (v4.1) |
| Fixes: 97f6cd39da22 ("md-cluster: re-add capabilities") |
| Signed-off-by: NeilBrown <neilb@suse.com> |
| Reviewed-by: Goldwyn Rodrigues <rgoldwyn@suse.com> |
| Signed-off-by: Shaohua Li <shli@fb.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/md/md.c | 4 +++- |
| 1 file changed, 3 insertions(+), 1 deletion(-) |
| |
| --- a/drivers/md/md.c |
| +++ b/drivers/md/md.c |
| @@ -2823,7 +2823,8 @@ state_store(struct md_rdev *rdev, const |
| err = 0; |
| } |
| } else if (cmd_match(buf, "re-add")) { |
| - if (test_bit(Faulty, &rdev->flags) && (rdev->raid_disk == -1)) { |
| + if (test_bit(Faulty, &rdev->flags) && (rdev->raid_disk == -1) && |
| + rdev->saved_raid_disk >= 0) { |
| /* clear_bit is performed _after_ all the devices |
| * have their local Faulty bit cleared. If any writes |
| * happen in the meantime in the local node, they |
| @@ -8594,6 +8595,7 @@ static int remove_and_add_spares(struct |
| if (mddev->pers->hot_remove_disk( |
| mddev, rdev) == 0) { |
| sysfs_unlink_rdev(mddev, rdev); |
| + rdev->saved_raid_disk = rdev->raid_disk; |
| rdev->raid_disk = -1; |
| removed++; |
| } |
