Re: [PATCH] nvmet: disable direct I/O when unavailable

[Bart Van Assche]

On 2/25/19 1:37 AM, Johannes Thumshirn wrote:
> On 24/02/2019 11:54, Max Gurtovoy wrote:
> > What is the status of iSCSI/SRP targets in this case ?
>
> iSCSI/SRP passes in the following:
>
>   /*
>    * Use O_DSYNC by default instead of O_SYNC to forgo syncing
>    * of pure timestamp updates.
>    */
>   flags = O_RDWR | O_CREAT | O_LARGEFILE | O_DSYNC;

That code fragment comes from the LIO file backend. There is no 
requirement for a SCSI target core file backend to use O_DSYNC. SCST 
allows users to choose whether or not O_DSYNC should be used:

	if (virt_dev->wt_flag && !virt_dev->nv_cache)
		open_flags |= O_DSYNC;

Bart.