Date: Thu, 21 Jan 2016 08:03:25 -0700 From: alan somers <asomers@gmail.com> To: Slawa Olhovchenkov <slw@zxy.spb.ru> Cc: Andriy Gapon <avg@freebsd.org>, Alan Somers <asomers@freebsd.org>, "svn-src-head@freebsd.org" <svn-src-head@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, "src-committers@freebsd.org" <src-committers@freebsd.org> Subject: Re: svn commit: r294329 - in head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs: . sys Message-ID: <CAOtMX2jB_Zsy-inXHTrehGjN2Xd4f=4TOvd5g-ZB4ho==-psPA@mail.gmail.com> In-Reply-To: <20160121113813.GG37895@zxy.spb.ru> References: <201601191700.u0JH0P6k061610@repo.freebsd.org> <569E6DA0.9010300@pix.net> <CAOtMX2idrWOpWbkYxPFn3yur8w-vgfBryhT4_0yiBvg10sWWRA@mail.gmail.com> <569F516D.80303@FreeBSD.org> <CAOtMX2gs37OnLMXE4zCduZF94%2B5z-TgPW%2Bqg8K8BweauLCRgDQ@mail.gmail.com> <56A019A1.4030900@FreeBSD.org> <20160121113813.GG37895@zxy.spb.ru>
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On Thu, Jan 21, 2016 at 4:38 AM, Slawa Olhovchenkov <slw@zxy.spb.ru> wrote: > On Thu, Jan 21, 2016 at 01:34:57AM +0200, Andriy Gapon wrote: > >> On 20/01/2016 22:03, Alan Somers wrote: >> > On Wed, Jan 20, 2016 at 2:20 AM, Andriy Gapon <avg@freebsd.org> wrote: >> >> On 19/01/2016 19:20, Alan Somers wrote: >> >>> The thing is, it never really worked in the first place. Panics and >> >>> deadlocks are so frequent that I don't think the feature was usable >> >>> for anybody. >> >> >> >> The feature is perfectly usable for me. I have never run into the problems that >> >> you describe. Why not fix the real bugs that you've run into? >> > >> > Spectra Logic and iXSystems both experienced many problems with this. >> > The worst is a deadlock that can be triggered simply by pulling a >> > drive from a redundant pool when there exists a zvol anywhere in the >> > system (see https://reviews.freebsd.org/D4998 for a quick way to >> > reproduce). Fixing it correctly would likely require far more time >> > than I have available. I just want the bugs to go away. See that >> > same code review for a change to make the feature optional. >> >> I think that we all want all the bugs to go way. One way to remove bugs is to >> remove (disable) code that contains bugs. That way the perfect bug-free >> software is clearly achievable :-) Unfortunately, that technique is not always >> welcomed. >> >> P.S. >> I think that the real problem here is that a method of a geom must never drop >> topology_lock. In other words, the GEOM management code (like g_xxx() stuff in >> geom_subr.c) expects that a topology can not change underneath it. But >> zvol_geom_access() clearly breaks that contract. > > May be same cause problem with swap on zvol (don't test on latest > -stable)? I'm not familiar with that problem. Is there a PR?
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