The following commit has been merged in the linux branch: commit 6cafb12dc85a5bdc722791cc5070968413264909 Author: Mark McLoughlin markmc@redhat.com Date: Sat Oct 24 14:14:31 2009 +0200
block: silently error unsupported empty barriers too
With 2.6.32-rc5 in a KVM guest using dm and virtio_blk, we see the following errors:
end_request: I/O error, dev vda, sector 0 end_request: I/O error, dev vda, sector 0
The errors go away if dm stops submitting empty barriers, by reverting:
commit 52b1fd5a27c625c78373e024bf570af3c9d44a79 Author: Mikulas Patocka mpatocka@redhat.com dm: send empty barriers to targets in dm_flush
We should silently error all barriers, even empty barriers, on devices like virtio_blk which don't support them.
See also:
https://bugzilla.redhat.com/514901
Signed-off-by: Mark McLoughlin markmc@redhat.com Signed-off-by: Mike Snitzer snitzer@redhat.com Acked-by: Alasdair G Kergon agk@redhat.com Acked-by: Mikulas Patocka mpatocka@redhat.com Cc: Rusty Russell rusty@rustcorp.com.au Cc: Neil Brown neilb@suse.de Cc: Christoph Hellwig hch@infradead.org Signed-off-by: Jens Axboe jens.axboe@oracle.com
diff --git a/block/blk-core.c b/block/blk-core.c index ac0fa10..71da511 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1161,7 +1161,7 @@ static int __make_request(struct request_queue *q, struct bio *bio) const unsigned int ff = bio->bi_rw & REQ_FAILFAST_MASK; int rw_flags;
- if (bio_rw_flagged(bio, BIO_RW_BARRIER) && bio_has_data(bio) && + if (bio_rw_flagged(bio, BIO_RW_BARRIER) && (q->next_ordered == QUEUE_ORDERED_NONE)) { bio_endio(bio, -EOPNOTSUPP); return 0;