Commit 4706b349 authored Feb 06, 2009 by NeilBrown

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>

parent eda58a85

drivers/md/raid1.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -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),