Date: Sat, 14 Mar 2009 02:47:54 +0100 From: Attilio Rao <attilio@freebsd.org> To: John Baldwin <jhb@freebsd.org> Cc: Pawel Jakub Dawidek <pjd@freebsd.org>, "freebsd-current@freebsd.org" <freebsd-current@freebsd.org>, Tim Kientzle <kientzle@freebsd.org>, Mark Powell <M.S.Powell@salford.ac.uk>, Anonymous <swell.k@gmail.com>, Peter Schuller <peter.schuller@infidyne.com> Subject: Re: repeatable ZFS panic: share->excl Message-ID: <3bbf2fe10903131847q464a98a0rb24b172e6c16315b@mail.gmail.com> In-Reply-To: <49BAA103.2060508@FreeBSD.org> References: <20090312175345.Y80227@rust.salford.ac.uk> <20090312191333.GA97342@hyperion.scode.org> <49B97617.8010709@freebsd.org> <86r6124f2v.fsf@gmail.com> <3bbf2fe10903122035i20b2767cod2322c39c6f850ee@mail.gmail.com> <29C8FA04-D5B1-49B7-ACF0-4185537367B0@baldwin.cx> <3bbf2fe10903122156u650417f0s5c49b68bdf4ffa07@mail.gmail.com> <49BA9801.5080505@FreeBSD.org> <49BAA103.2060508@FreeBSD.org>
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2009/3/13, John Baldwin <jhb@freebsd.org>: > John Baldwin wrote: > > > Attilio Rao wrote: > > > > > 2009/3/13, John Baldwin <john@baldwin.cx>: > > > > > > > This is similar to the patch I've asked lulf@ to test except that it > is longer and I fix a bug where zfs_lookup() can leak a vnode lock if the > access check fails. :-) The last one I sent to lulf@ is at > www.FreeBSD.org/~jhb/patches/zfs_ea.patch. > > > > > > > > > > I really thought zfs_lookup() was returning the lock held as a feature > assming no LOCKLEAF. Is that a bug instead? > > > > > > > Yes, I think that is the real bug. Looking at this further I think > > zfs_get_xattrdir() will return the vnode locked if it has to create a > > new node via zfs_make_attrdir() but only returns it held and unlocked if > > it finds an existing one. So my new patch is to just fix > > zfs_get_xattrdir() to unlock the vnode if it creates a new one like so: > > > > (Sorry, TBird is probably going to butcher all the whitespace): > > > > --- > > > //depot/user/jhb/lock/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_dir.c > > +++ > > > /Users/jhb/work/p4/lock/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_dir.c > > @@ -940,6 +940,7 @@ > > /* NB: we already did dmu_tx_wait() if necessary */ > > goto top; > > } > > + VOP_UNLOCK(*xvpp, 0); > > > > return (error); > > } > > > > A non-butchered version is at > www.FreeBSD.org/~jhb/patches/zfs_ea.patch. > > > > So lulf@ reports success with this patch. Pawel, can you review it? Yeah, I proposed to lulf this same patch yesterday, I just didn't wait for him to complete the test because I had to sleep, so I think this is the right fix. Thanks, Attilio -- Peace can only be achieved by understanding - A. Einstein
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