[dm-devel] block: properly handle flush/fua requests in blk_insert_cloned_request
Vivek Goyal
vgoyal at redhat.com
Tue Aug 9 19:05:09 UTC 2011
On Tue, Aug 09, 2011 at 02:55:31PM -0400, Mike Snitzer wrote:
[..]
> > > + /*
> > > + * All FLUSH/FUA requests are expected to have gone through the
> > > + * flush machinary. If a request's cmd_flags doesn't match the
> > > + * flush_flags of the underlying request_queue it is a bug.
> > > + */
> > > + BUG_ON((rq->cmd_flags & REQ_FLUSH) && !(q->flush_flags & REQ_FLUSH));
> > > + BUG_ON((rq->cmd_flags & REQ_FUA) && !(q->flush_flags & REQ_FUA));
> > > +
> >
> > Actually this makes sense and is simple. :-) Is BUG_ON() too harsh, how
> > about WARN_ONCE() variants? To me system continues to work so warning
> > is probably good enough.
>
> Sure, WARN_ONCE() is fine by me.
>
> Seems Tejun wants a more involved fix though.
Fixing it properly doesn't hurt. Makes it more future proof. In fact I am
thinking what happens to blk_execute_rq() variants where one can prepare a
request and send it down. What if caller sets FLUSH/FUA flags there.
Thanks
Vivek
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