From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Sat, 4 Aug 2018 14:19:51 -0400 From: Mike Snitzer To: Linus Torvalds Cc: wgh@torlan.ru, Theodore Ts'o , Jens Axboe , Sagi Grimberg , Linux Kernel Mailing List , linux-block , dm-devel@redhat.com, Ilya Dryomov , Zdenek Kabelac Subject: Re: LVM snapshot broke between 4.14 and 4.16 Message-ID: <20180804181950.GA10514@redhat.com> References: <1ec0a220-d5b0-1c27-e63b-c4d3f4ce9d77@torlan.ru> <20180803133102.GA3092@redhat.com> <20180803152034.GD32066@thunk.org> <20180803183932.GA3258@redhat.com> <20180803190617.GA4498@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: List-ID: On Sat, Aug 04 2018 at 1:04pm -0400, Linus Torvalds wrote: > On Sat, Aug 4, 2018 at 3:03 AM WGH wrote: > > > > > > > The patch works for me. > > > > However, there's no text messsage in the kernel log, just a traceback. I > > think that's because WARN_ONCE is supposed to take condition as a first > > argument. > > Duh. > > It needs to be WARN_ONCE(1, ...); > > I obviously didn't test that patch, but I _did_ compile it. I wonder > why I didn't get a compiler warning for it... > > [ Goes off and looks ] > > Oh, because the "bio_devname(bio, b)" argument ended up being > interpreted as the format string, and since it was a dynamic string > the compiler felt it was all fine. Just bad luck. > > Anyway, just out of curiosity, what was the traceback? > > I'm not entirely happy with that patch either (even after the obvious > fix to add the "1" argument), but it does seem like the minimal > temporary workaround for now. I agree. Please feel free to add my: Acked-by: Mike Snitzer