[Devel] [RFC PATCH vz9 v6 56/62] dm-ploop: support REQ_FUA for data pios

[Andrey Zhadchenko]

No, REQ_FUA does not oblige us to make sync. REQ_FUA is translated into 
IOCB_DSYNC. It is IOCB layer job to datasync this exact request.
Also REQ_FUA usually is coupled with REQ_PREFLUSH and we already handle 
that.

On 12/5/24 22:56, Alexander Atanasov wrote:
> If we see a bio with REQ_FUA set we need to request a sync.
> 
> https://virtuozzo.atlassian.net/browse/VSTOR-91816
> Signed-off-by: Alexander Atanasov <alexander.atanasov at virtuozzo.com>
> ---
>   drivers/md/dm-ploop-map.c | 8 ++++++++
>   1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/md/dm-ploop-map.c b/drivers/md/dm-ploop-map.c
> index c47fa48f1da6..970f0dc52307 100644
> --- a/drivers/md/dm-ploop-map.c
> +++ b/drivers/md/dm-ploop-map.c
> @@ -223,6 +223,14 @@ static void ploop_do_pio_endio(struct pio *pio)
>   	if (!atomic_dec_and_test(&pio->remaining))
>   		return;
>   
> +	/* REQ_FUA requires us to flush all before pio is completed */
> +	if (pio->bi_op & REQ_FUA) {
> +		struct file *file;
> +
> +		file = ploop_top_delta(pio->ploop)->file;
> +		vfs_fsync(file, 1);
> +	}
> +
>   	endio_cb(pio, endio_cb_data, pio->bi_status);
>   
>   	if (free_on_endio)