On Tue, 2010-01-26 at 13:48 -0500, Dave Wysochanski wrote:
> On Tue, 2010-01-26 at 13:09 -0500, Mike Snitzer wrote:
> > On Tue, Jan 26 2010 at 12:56pm -0500,
> > Dave Wysochanski <dwysocha@xxxxxxxxxx> wrote:
> >
> > > Resume ioctls may result in no changes to the device and thus they
> > > should not generate change uevents. For example, if a device is
> > > not suspended when a resume ioctl occurs, we should not send a
> > > uevent.
> > >
> > > Signed-off-by: Dave Wysochanski <dwysocha@xxxxxxxxxx>
> > > ---
> > > drivers/md/dm-ioctl.c | 12 ++++++++----
> > > 1 files changed, 8 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
> > > index 1d66932..0c1cf53 100644
> > > --- a/drivers/md/dm-ioctl.c
> > > +++ b/drivers/md/dm-ioctl.c
> > > @@ -851,6 +851,7 @@ static int do_suspend(struct dm_ioctl *param)
> > >
> > > static int do_resume(struct dm_ioctl *param)
> > > {
> > > + int send_uevent = 0;
> > > int r = 0;
> > > unsigned suspend_flags = DM_SUSPEND_LOCKFS_FLAG;
> > > struct hash_cell *hc;
> > > @@ -895,18 +896,21 @@ static int do_resume(struct dm_ioctl *param)
> > > set_disk_ro(dm_disk(md), 0);
> > > else
> > > set_disk_ro(dm_disk(md), 1);
> > > + send_uevent = 1;
> > > }
> > > -
> > > - if (dm_suspended_md(md))
> > > + if (dm_suspended_md(md)) {
> > > r = dm_resume(md);
> > > + send_uevent = 1;
> > > + }
> > >
> > > if (old_map)
> > > dm_table_destroy(old_map);
> > >
> > > - if (!r) {
> > > + if (send_uevent)
> > > dm_kobject_uevent(md, KOBJ_CHANGE, param->event_nr);
> > > +
> > > + if (!r)
> > > r = __dev_status(md, param);
> > > - }
> > >
> > > dm_put(md);
> > > return r;
> >
> > Seems you're sending the uevent even if resume failed. Is that intended?
> >
> > Also, can dm_kobject_uevent() come before dm_table_destroy()?
> >
> > If so this would be a bit simpler:
> >
> > diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
> > index 1d66932..e3cf568 100644
> > --- a/drivers/md/dm-ioctl.c
> > +++ b/drivers/md/dm-ioctl.c
> > @@ -897,16 +897,17 @@ static int do_resume(struct dm_ioctl *param)
> > set_disk_ro(dm_disk(md), 1);
> > }
> >
> > - if (dm_suspended_md(md))
> > + if (dm_suspended_md(md)) {
> > r = dm_resume(md);
> > + if (!r)
> > + dm_kobject_uevent(md, KOBJ_CHANGE, param->event_nr);
> > + }
> >
> > if (old_map)
> > dm_table_destroy(old_map);
> >
> > - if (!r) {
> > - dm_kobject_uevent(md, KOBJ_CHANGE, param->event_nr);
> > + if (!r)
> > r = __dev_status(md, param);
> > - }
> >
> > dm_put(md);
> > return r;
> >
> > --
> > dm-devel mailing list
> > dm-devel@xxxxxxxxxx
> > https://www.redhat.com/mailman/listinfo/dm-devel
>
> Nice simplification Mike, as discussed on IRC.
>
> Ack.
>
Actually, the more I think about it I am not sure about sending the
uevent in the case where dm_resume() fails. Seems like we should send
it since the map could have changed - depends on whether we went through
that 'if (new_map)' block.
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