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

[jthumshirn@suse.de (Johannes Thumshirn)]

On Mon, Feb 25, 2019@06:49:04AM -0800, Bart Van Assche wrote:
> 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:

Yes, LIO file backend is the in-tree equivalent to NVMe's file backend. That's
why I copied it here.


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

OK. Do your open_flags include O_DIRECT per default as well?

Byte,
	Johannes
-- 
Johannes Thumshirn                            SUSE Labs Filesystems
jthumshirn at suse.de                                +49 911 74053 689
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 N?rnberg
GF: Felix Imend?rffer, Jane Smithard, Graham Norton
HRB 21284 (AG N?rnberg)
Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850