drbd: correctly submit flush bio on barrier

commit 3899d94e3831ee07ea6821c032dc297aec80586a upstream.

When we receive a flush command (or "barrier" in DRBD), we currently use
a REQ_OP_FLUSH with the REQ_PREFLUSH flag set.

The correct way to submit a flush bio is by using a REQ_OP_WRITE without
any data, and set the REQ_PREFLUSH flag.

Since commit b4a6bb3a67aa ("block: add a sanity check for non-write
flush/fua bios"), this triggers a warning in the block layer, but this
has been broken for quite some time before that.

So use the correct set of flags to actually make the flush happen.

Cc: Christoph Hellwig <hch@infradead.org>
Cc: stable@vger.kernel.org
Fixes: f9ff0da56437 ("drbd: allow parallel flushes for multi-volume resources")
Reported-by: Thomas Voegtle <tv@lio96.de>
Signed-off-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230503121937.17232-1-christoph.boehmwalder@linbit.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index a7c180426c601bb140bfc96292846dee17531450..5a63010f2af3985bff6a7331dd06a04b98afe8c1 100644 (file)
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -1309,7 +1309,7 @@ static void submit_one_flush(struct drbd_device *device, struct issue_flush_cont
        bio_set_dev(bio, device->ldev->backing_bdev);
        bio->bi_private = octx;
        bio->bi_end_io = one_flush_endio;
-       bio->bi_opf = REQ_OP_FLUSH | REQ_PREFLUSH;
+       bio->bi_opf = REQ_OP_WRITE | REQ_PREFLUSH;
 
        device->flush_jif = jiffies;
        set_bit(FLUSH_PENDING, &device->flags);