md/raid10: Fix bug when activating a hot-spare.
This is a fairly serious bug in RAID10.
When a RAID10 array is degraded and a hot-spare is activated, the
spare does not take up the empty slot, but rather replaces the first
working device.
This is likely to make the array non-functional. It would normally
be possible to recover the data, but that would need care and is not
guaranteed.
This bug was introduced in commit
2bb77736ae5dca0a189829fbb7379d43364a9dac
which first appeared in 3.1.
Cc: stable@kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 132c18e..c025a82 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1355,7 +1355,7 @@
struct mirror_info *p = &conf->mirrors[mirror];
if (p->recovery_disabled == mddev->recovery_disabled)
continue;
- if (!p->rdev)
+ if (p->rdev)
continue;
disk_stack_limits(mddev->gendisk, rdev->bdev,