Commit 6cafb12d authored by Mark McLoughlin's avatar Mark McLoughlin Committed by Jens Axboe

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 52b1fd5a
  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/514901Signed-off-by: default avatarMark McLoughlin <markmc@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
Acked-by: default avatarAlasdair G Kergon <agk@redhat.com>
Acked-by: default avatarMikulas 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: default avatarJens Axboe <jens.axboe@oracle.com>
parent d995053d
...@@ -1161,7 +1161,7 @@ static int __make_request(struct request_queue *q, struct bio *bio) ...@@ -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; const unsigned int ff = bio->bi_rw & REQ_FAILFAST_MASK;
int rw_flags; 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)) { (q->next_ordered == QUEUE_ORDERED_NONE)) {
bio_endio(bio, -EOPNOTSUPP); bio_endio(bio, -EOPNOTSUPP);
return 0; return 0;
......
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