Re: [RFC PATCH v3 07/11] iomap: Add DSYNC support to RWF_WRITETHROUGH

[Pankaj Raghav (Samsung)]

>  		return -EINVAL;
>  
> +	/*
> +	 * If we realise that cache flush is necessary (eg FUA is not present
> +	 * or we need metadata updates) then we turn off the optimization.
> +	 */
> +	if (wt_ctx->use_fua) {
> +		if (iter->iomap.type != IOMAP_MAPPED ||
> +		    (iter->iomap.flags &
> +		     (IOMAP_F_NEW | IOMAP_F_SHARED | IOMAP_F_DIRTY)) ||

> +		    (bdev_write_cache(iter->iomap.bdev) &&
> +		     !bdev_fua(iter->iomap.bdev)))
Shouldn't this be similar to DIO code: !bdev_write_cache() || bdev_fua()
?

As long as bdev_fua() is supported, it does not matter if the
bdev_write_cache is there or not right?

> +			wt_ctx->use_fua = false;
> +	}
> +

--
Pankaj