Date: Sun, 1 Jun 2003 10:39:12 -0700 (PDT) From: Don Lewis <truckman@FreeBSD.org> To: des@ofug.org Cc: cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/fs/pseudofs pseudofs_vnops.c Message-ID: <200306011739.h51HdCM7004578@gw.catspoiler.org> In-Reply-To: <xzpr86e3u28.fsf@flood.ping.uio.no>
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On 1 Jun, Dag-Erling Smorgrav wrote:
> Don Lewis <truckman@FreeBSD.org> writes:
>> Modified files:
>> sys/fs/pseudofs pseudofs_vnops.c
>> Log:
>> Don't unlock the parent directory vnode twice if the ISDOTDOT flag
>> is set.
>
> des@dwp ~% grep pseudofs /usr/src/MAINTAINERS
> pseudofs des Advance notification requested.
Sorry, though ...
------ Forwarded message ------
From: Don Lewis <truckman@FreeBSD.org>
Subject: possible patch for vnode double unlock in pfs_lookup()
Date: Wed, 21 May 2003 23:20:49 -0700 (PDT)
To: des@FreeBSD.org, jeff@FreeBSD.org
Cc: current@FreeBSD.org
If the ISDOTDOT flag is set and the lockparent or ISLASTCN flags are not
set, pfs_lookup() unlocks the same vnode twice. This can be observed by
running
find / -print
with the DEBUG_VFS_LOCKS kernel option enabled.
I think the following is the correct patch:
I believe that it is safe to defer committing a fix until after
5.1-RELEASE.
Index: sys/fs/pseudofs/pseudofs_vnops.c
===================================================================
RCS file: /home/ncvs/src/sys/fs/pseudofs/pseudofs_vnops.c,v
retrieving revision 1.35
diff -u -r1.35 pseudofs_vnops.c
--- sys/fs/pseudofs/pseudofs_vnops.c 2 Mar 2003 22:23:45 -0000 1.35
+++ sys/fs/pseudofs/pseudofs_vnops.c 22 May 2003 04:40:09 -0000
@@ -411,7 +411,8 @@
vn_lock(vn, LK_EXCLUSIVE|LK_RETRY, cnp->cn_thread);
cnp->cn_flags &= ~PDIRUNLOCK;
}
- if (!lockparent || !(cnp->cn_flags & ISLASTCN))
+ if ((!lockparent || !(cnp->cn_flags & ISLASTCN)) &&
+ !(cnp->cn_flags & ISDOTDOT))
VOP_UNLOCK(vn, 0, cnp->cn_thread);
/*
------ End forwarded message ------
The patch I committed DeMorgan-ized the expression so that it isn't
quite as !-happy.
You might also want to look for the message I sent to -current about 8
hours ago with the subject "vnode locking problem in pseudofs/procfs".
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