Date: Wed, 8 May 2013 22:48:46 +0200 From: Peter Holm <peter@holm.cc> To: Konstantin Belousov <kostikbel@gmail.com> Cc: freebsd-stable@freebsd.org Subject: Re: Nullfs leaks i-nodes Message-ID: <20130508204846.GA3806@x2.osted.lan> In-Reply-To: <20130508175856.GA32341@x2.osted.lan> References: <B799E3B928B18B9E6C68F912@[172.16.2.62]> <20130508091317.GJ3047@kib.kiev.ua> <20130508175856.GA32341@x2.osted.lan>
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On Wed, May 08, 2013 at 07:58:56PM +0200, Peter Holm wrote: > On Wed, May 08, 2013 at 12:13:17PM +0300, Konstantin Belousov wrote: > > On Tue, May 07, 2013 at 08:30:06AM +0200, G??ran L??wkrantz wrote: > > > I created a PR, kern/178238, on this but would like to know if anyone has > > > any ideas or patches? > > > > > > Have updated the system where I see this to FreeBSD 9.1-STABLE #0 r250229 > > > and still have the problem. > > > > The patch below should fix the issue for you, at least it did so in my > > limited testing. > > > > What is does: > > 1. When inactivating a nullfs vnode, check if the lower vnode is > > unlinked, and reclaim upper vnode if so. [This fixes your case]. > > > > 2. Besides a callback to the upper filesystems for the lower vnode > > reclaimation, it also calls the upper fs for lower vnode unlink. > > This allows nullfs to purge cached vnodes for the unlinked lower. > > [This fixes an opposite case, when the vnode is removed from the > > lower mount, but upper aliases prevent the vnode from being > > recycled]. > > > > 3. Fix a wart which existed from the introduction of the nullfs caching, > > do not unlock lower vnode in the nullfs_reclaim_lowervp(). It should > > be completely innocent, but now it is also formally safe. > > > > 4. Fix vnode reference leak in nullfs_reclaim_lowervp(). > > > > Please note that the patch is basically not tested, I only verified your > > scenario and a mirror of it as described in item 2. > > > > diff --git a/sys/fs/nullfs/null.h b/sys/fs/nullfs/null.h > > index 4f37020..a624be6 100644 > > I got this page fault after interrupting a nullfs test that had been > running for three hours: > > http://people.freebsd.org/~pho/stress/log/kostik562.txt > Seems to be easily reproduced, so I compiled null_vnops.c and fifo_vnops.c without "-O" in order to get some more info: http://people.freebsd.org/~pho/stress/log/kostik563.txt - Peter
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