Commit 5cfb22a1 authored by NeilBrown's avatar NeilBrown
Browse files

md/raid5: prefer replacing failed devices over want-replacement devices. 



If a RAID5 has both a failed device and a device marked as
'WantReplacement', then we should preferentially replace the failed
device.
However the current code replaces whichever is found first.
So split into 2 loops, check fail failed/missing first, and only check
for WantReplacement if nothing is failed or missing.

Reported-by: default avatarmajianpeng <majianpeng@gmail.com>
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
parent fc448a18

drivers/md/raid5.c

+8 −5
Original line number Diff line number Diff line
@@ -5465,10 +5465,9 @@ static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev) 
	if (rdev->saved_raid_disk >= 0 &&

	    rdev->saved_raid_disk >= first &&

	    conf->disks[rdev->saved_raid_disk].rdev == NULL)

		disk = rdev->saved_raid_disk;

	else

		disk = first;

	for ( ; disk <= last ; disk++) {

		first = rdev->saved_raid_disk;



	for (disk = first; disk <= last; disk++) {

		p = conf->disks + disk;

		if (p->rdev == NULL) {

			clear_bit(In_sync, &rdev->flags);
@@ -5477,8 +5476,11 @@ static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev) 
			if (rdev->saved_raid_disk != disk)

				conf->fullsync = 1;

			rcu_assign_pointer(p->rdev, rdev);

			break;

			goto out;

		}

	}

	for (disk = first; disk <= last; disk++) {

		p = conf->disks + disk;

		if (test_bit(WantReplacement, &p->rdev->flags) &&

		    p->replacement == NULL) {

			clear_bit(In_sync, &rdev->flags);
@@ -5490,6 +5492,7 @@ static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev) 
			break;

		}

	}

out:

	print_raid5_conf(conf);

	return err;

}

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