From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753337Ab1HITFS (ORCPT ); Tue, 9 Aug 2011 15:05:18 -0400 Received: from mx1.redhat.com ([209.132.183.28]:4155 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752245Ab1HITFQ (ORCPT ); Tue, 9 Aug 2011 15:05:16 -0400 Date: Tue, 9 Aug 2011 15:05:09 -0400 From: Vivek Goyal To: Mike Snitzer Cc: Tejun Heo , Jeff Moyer , linux-kernel@vger.kernel.org, Jens Axboe , dm-devel@redhat.com Subject: Re: block: properly handle flush/fua requests in blk_insert_cloned_request Message-ID: <20110809190509.GA31927@redhat.com> References: <20110809153826.GB23842@htj.dyndns.org> <20110809161334.GC23842@htj.dyndns.org> <20110809174347.GA13293@redhat.com> <20110809175237.GA978@redhat.com> <20110809185531.GC13293@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110809185531.GC13293@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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