Date: Thu, 7 Jun 2012 08:17:26 -0400 From: John Baldwin <jhb@freebsd.org> To: freebsd-fs@freebsd.org Cc: pho@freebsd.org Subject: Re: close() of an flock'd file is not atomic Message-ID: <201206070817.26342.jhb@freebsd.org> In-Reply-To: <20120607062703.P955@besplex.bde.org> References: <201203071318.08241.jhb@freebsd.org> <20120606183949.GR85127@deviant.kiev.zoral.com.ua> <20120607062703.P955@besplex.bde.org>
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On Wednesday, June 06, 2012 4:34:23 pm Bruce Evans wrote: > On Wed, 6 Jun 2012, Konstantin Belousov wrote: > > > On Wed, Jun 06, 2012 at 08:17:54AM -0400, John Baldwin wrote: > >>... > >> The vn_open_vnode() patch is at > >> http://www.freebsd.org/~jhb/patches/vn_open_vnode.patch > >> > >> I tested it by doing a buildworld -j 32 in a loop while NFS exporting the > >> /usr/obj tree to another machine that did a continual find | xargs md5 loop > >> over the /usr/obj tree. This survived overnight. > > > > There is #if 0 left in fhopen() which translates ERESTART into EINTR. Is > > it needed ? > > > > Otherwise it looks fine (but still quite hard to read). > > This translation in the old code causes the following bogus behaviour: > - some device drivers try to restart open() after revoke(). They return > ERESTART for this. But open never restarts, due to this translation. > Never restarting may be correct, but EINTR is a bogus errno unless the > open was actually interrupted by a signal, in which case the driver > should have returned EINTR. ENXIO is closest to describing "killed > by revoke". > > What case is the translation supposed to fix? I have no idea. :( I will take it out of fhopen() however since presumably fhopen() will not be used on devices (devfs doesn't have VOPs for filehandles and is not exportable). -- John Baldwin
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