When we receive a flush command (or "barrier" in DRBD), we currently use
a REQ_OP_FLUSH with the REQ_PREFLUSH flag set.
REQ_OP_FLUSH is supposed to be an empty bio with the sole purpose of
flushing the disk. REQ_PREFLUSH is used for REQ_OP_WRITE bios to
additionally signal that a flush should be issued, so it is redundant
here.
Since commit b4a6bb3a67aa ("block: add a sanity check for non-write
flush/fua bios"), this triggers a warning in the block layer.
So remove the REQ_PREFLUSH flag when allocating the bio.
Fixes: f9ff0da56437 ("drbd: allow parallel flushes for multi-volume resources")
Reported-by: Thomas Voegtle <[email protected]>
Signed-off-by: Christoph Böhmwalder <[email protected]>
---
drivers/block/drbd/drbd_receiver.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index e54404c632e7..f2479c29197a 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -1283,7 +1283,7 @@ static void one_flush_endio(struct bio *bio)
static void submit_one_flush(struct drbd_device *device, struct issue_flush_context *ctx)
{
struct bio *bio = bio_alloc(device->ldev->backing_bdev, 0,
- REQ_OP_FLUSH | REQ_PREFLUSH, GFP_NOIO);
+ REQ_OP_FLUSH, GFP_NOIO);
struct one_flush_context *octx = kmalloc(sizeof(*octx), GFP_NOIO);
if (!octx) {
--
2.39.2
On Tue, May 02, 2023 at 11:29:22AM +0200, Christoph B?hmwalder wrote:
> struct bio *bio = bio_alloc(device->ldev->backing_bdev, 0,
> - REQ_OP_FLUSH | REQ_PREFLUSH, GFP_NOIO);
> + REQ_OP_FLUSH, GFP_NOIO);
This isn't going to work. flush bios are (somewhat confusingly)
implemented as writes with no data and the preflush flag. So this
should be:
REQ_OP_WRITE | REQ_PREFLUSH.
and it looks like whatever flushing this does hasn't wroked for a long
time.
Am 03.05.23 um 06:18 schrieb Christoph Hellwig:
> On Tue, May 02, 2023 at 11:29:22AM +0200, Christoph Böhmwalder wrote:
>> struct bio *bio = bio_alloc(device->ldev->backing_bdev, 0,
>> - REQ_OP_FLUSH | REQ_PREFLUSH, GFP_NOIO);
>> + REQ_OP_FLUSH, GFP_NOIO);
>
> This isn't going to work. flush bios are (somewhat confusingly)
Indeed...
> implemented as writes with no data and the preflush flag. So this
> should be:
>
> REQ_OP_WRITE | REQ_PREFLUSH.
>
> and it looks like whatever flushing this does hasn't wroked for a long
> time.
Thanks for the hint. I'll prepare a v2 today.
--
Christoph Böhmwalder
LINBIT | Keeping the Digital World Running
DRBD HA — Disaster Recovery — Software defined Storage