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: majianpeng <majianpeng@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index d267672..95fcbbf 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -5465,10 +5465,9 @@
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 @@
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 @@
break;
}
}
+out:
print_raid5_conf(conf);
return err;
}