[PATCH 18/18] staging: lustre: osc: Lustre returns EINTR from writes when SA_RESTART is set

[James Simmons]

> Some of this series didn't apply, due to merge issues with 4.6-rc3.  Can
> you rebase and resend the remaining patches?

This patch conflicts with a patch landed from Oleg which is a better 
solution for this bug. We can drop this patch.

> 
> thanks,
> 
> greg k-h
> 
> On Mon, Apr 04, 2016 at 09:37:03PM -0400, James Simmons wrote:
> > When Lustre is in a read or write system call and receives a
> > SIGALRM, it will return EINTR if interrupted in osc_enter_cache.
> > This prevents the system call from being restarted if
> > SA_RESTART is set in the handler.
> > 
> > This patch changes behavior in this location to return ERESTARTSYS
> > when a signal arrives during the call to l_wait_event.
> > 
> > Signed-off-by: Patrick Farrell <paf at cray.com>
> > Signed-off-by: James Simmons <uja.ornl at gmail.com>
> > ntel-bug-id: https://jira.hpdd.intel.com/browse/LU-3581
> > Reviewed-on: http://review.whamcloud.com/7002
> > Reviewed-by: Rahul Deshmukh <rahul_deshmukh at xyratex.com>
> > Reviewed-by: Cory Spitz <spitzcor at cray.com>
> > Reviewed-by: Andreas Dilger <andreas.dilger at intel.com>
> > Signed-off-by: James Simmons <jsimmons at infradead.org>
> > ---
> >  drivers/staging/lustre/lustre/osc/osc_cache.c |   13 ++++++++++++-
> >  1 files changed, 12 insertions(+), 1 deletions(-)
> > 
> > diff --git a/drivers/staging/lustre/lustre/osc/osc_cache.c b/drivers/staging/lustre/lustre/osc/osc_cache.c
> > index f09b89d..956d57b 100644
> > --- a/drivers/staging/lustre/lustre/osc/osc_cache.c
> > +++ b/drivers/staging/lustre/lustre/osc/osc_cache.c
> > @@ -1626,11 +1626,22 @@ static int osc_enter_cache(const struct lu_env *env, struct client_obd *cli,
> >  
> >  		/* l_wait_event is interrupted by signal, or timed out */
> >  		if (rc < 0) {
> > -			if (rc == -ETIMEDOUT) {
> > +			switch (rc) {
> > +			case -ETIMEDOUT:
> >  				OSC_DUMP_GRANT(D_ERROR, cli,
> >  					       "try to reserve %d.\n", bytes);
> >  				osc_extent_tree_dump(D_ERROR, osc);
> >  				rc = -EDQUOT;
> > +				break;
> > +			case -EINTR:
> > +				/* Ensures restartability - LU-3581 */
> > +				rc = -ERESTARTSYS;
> > +				break;
> > +			default:
> > +				CDEBUG(D_CACHE, "%s: event for cache space @ %p never arrived due to %d\n",
> > +				       cli->cl_import->imp_obd->obd_name,
> > +				       &ocw, rc);
> > +				break;
> >  			}
> >  			list_del_init(&ocw.ocw_entry);
> >  			goto out;
> > -- 
> > 1.7.1
>