> The following warning was reported when doing fsync on a pmem device:
>
> ------------[ cut here ]------------
> WARNING: CPU: 2 PID: 384 at block/blk-core.c:751 submit_bio_noacct+0x340/0x520
> Modules linked in:
> CPU: 2 PID: 384 Comm: mkfs.xfs Not tainted 6.4.0-rc7+ #154
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
> RIP: 0010:submit_bio_noacct+0x340/0x520
> ......
> Call Trace:
> <TASK>
> ? asm_exc_invalid_op+0x1b/0x20
> ? submit_bio_noacct+0x340/0x520
> ? submit_bio_noacct+0xd5/0x520
> submit_bio+0x37/0x60
> async_pmem_flush+0x79/0xa0
> nvdimm_flush+0x17/0x40
> pmem_submit_bio+0x370/0x390
> __submit_bio+0xbc/0x190
> submit_bio_noacct_nocheck+0x14d/0x370
> submit_bio_noacct+0x1ef/0x520
> submit_bio+0x55/0x60
> submit_bio_wait+0x5a/0xc0
> blkdev_issue_flush+0x44/0x60
>
> The root cause is that submit_bio_noacct() needs bio_op() is either
> WRITE or ZONE_APPEND for flush bio and async_pmem_flush() doesn't assign
> REQ_OP_WRITE when allocating flush bio, so submit_bio_noacct just fail
> the flush bio.
>
> Simply fix it by adding the missing REQ_OP_WRITE for flush bio. And we
> could fix the flush order issue and do flush optimization later.
>
> Fixes: b4a6bb3a67aa ("block: add a sanity check for non-write flush/fua bios")
> Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx>
> ---
> v2:
> * do a minimal fix first (Suggested by Christoph)
> v1: https://lore.kernel.org/linux-block/ZJLpYMC8FgtZ0k2k@xxxxxxxxxxxxx/T/#t
>
> Hi Jens & Dan,
>
> I found Pankaj was working on the fix and optimization of virtio-pmem
> flush bio [0], but considering the last status update was 1/12/2022, so
> could you please pick the patch up for v6.4 and we can do the flush fix
> and optimization later ?
>
> [0]: https://lore.kernel.org/lkml/20220111161937.56272-1-pankaj.gupta.linux@xxxxxxxxx/T/
>
> drivers/nvdimm/nd_virtio.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/nvdimm/nd_virtio.c b/drivers/nvdimm/nd_virtio.c
> index c6a648fd8744..97098099f8a3 100644
> --- a/drivers/nvdimm/nd_virtio.c
> +++ b/drivers/nvdimm/nd_virtio.c
> @@ -105,7 +105,7 @@ int async_pmem_flush(struct nd_region *nd_region, struct bio *bio)
> * parent bio. Otherwise directly call nd_region flush.
> */
> if (bio && bio->bi_iter.bi_sector != -1) {
> - struct bio *child = bio_alloc(bio->bi_bdev, 0, REQ_PREFLUSH,
> + struct bio *child = bio_alloc(bio->bi_bdev, 0, REQ_OP_WRITE | REQ_PREFLUSH,
> GFP_ATOMIC);
>
> if (!child)
Fix looks good to me. Will give a run soon.
Yes, [0] needs to be completed. Curious to know if you guys using
virtio-pmem device?
Thanks,
Pankaj
