From dfeb333b590c78d0dbadfa00a56635f1b2489d58 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Thu, 26 Apr 2018 14:46:29 +1000 Subject: md: fix two problems with setting the "re-add" device state. 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: (v4.1) Fixes: 97f6cd39da22 ("md-cluster: re-add capabilities") Signed-off-by: NeilBrown Reviewed-by: Goldwyn Rodrigues Signed-off-by: Shaohua Li Signed-off-by: Greg Kroah-Hartman --- drivers/md/md.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'drivers/md') diff --git a/drivers/md/md.c b/drivers/md/md.c index 24e64b04424a..7143c8b9284b 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -2823,7 +2823,8 @@ state_store(struct md_rdev *rdev, const char *buf, size_t len) 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 mddev *mddev, 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++; } -- cgit v1.2.3