From: NeilBrown <neilb@suse.de>
Date: Fri, 6 Feb 2009 04:06:47 +0000 (+1100)
Subject: md: Allow read error in a single drive raid1 to be passed up.
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=4706b349f4a8312d31b3d0cf61fe721699356920;p=GitHub%2FLineageOS%2Fandroid_kernel_samsung_universal7580.git

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 7b4f5f7155d..01e3cffd03b 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1640,7 +1640,8 @@ static void raid1d(mddev_t *mddev)
 			}
 
 			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),