md: Allow read error in a single drive raid1 to be passed up.
If a raid1 only has a single working device and gets a read error,
we choose to simply return that error up to the filesystem (or whatever)
rather than failing the whole array.
However the codes doesn't quite do that. We attempt a readbalance
which allocates the same drive, so we retry the read - indefinitely.
Instead: If read_balance in the error case chooses the same drive that just
failed, treat it as a failure and don't retry.
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 7b4f5f7..01e3cff 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1640,7 +1640,8 @@
}
bio = r1_bio->bios[r1_bio->read_disk];
- if ((disk=read_balance(conf, r1_bio)) == -1) {
+ if ((disk=read_balance(conf, r1_bio)) == -1 ||
+ disk == r1_bio->read_disk) {
printk(KERN_ALERT "raid1: %s: unrecoverable I/O"
" read error for block %llu\n",
bdevname(bio->bi_bdev,b),