From: Trond Myklebust <trond.myklebust@fys.uio.no>
To: Chuck Lever <chuck.lever@oracle.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>,
Neil Brown <neilb@suse.de>, Steve Dickson <SteveD@redhat.com>,
NFSv3 list <linux-nfs@vger.kernel.org>,
Mi Jinlong <mijinlong@cn.fujitsu.com>
Subject: Re: [RFC] server's statd and lockd will not sync after its nfslock restart
Date: Thu, 17 Dec 2009 15:48:03 -0500 [thread overview]
Message-ID: <1261082883.4080.28.camel@localhost> (raw)
In-Reply-To: <76D5AD4C-2DDA-4A12-BD53-168D04CA9E7C@oracle.com>
On Thu, 2009-12-17 at 15:34 -0500, Chuck Lever wrote:
> On Dec 17, 2009, at 3:27 PM, Trond Myklebust wrote:
> > One alternative might be to just record the kernel's random boot_id in
> > the pid file. That gets regenerated on each boot, so should be unique.
>
> Where do you get it in user space? Is it available on earlier
> kernels? ("should be unique" -- I hope it doesn't have the same
> problem we had with XID replay on diskless systems).
You can access it from userland as the 'kernel.random.boot_id' sysctl.
It is available on 2.4 kernels and newer.
It is based on the kernel random number generator, so should be
reasonably unique.
> Fwiw, I tried using the boot time stamp at one point, but
> unfortunately that's adjusted by the ntp offset, so it can take
> different values over time. It was difficult to compare it to a time
> stamp recorded in a file.
Agreed. You can't rely on time stamps.
Trond
next prev parent reply other threads:[~2009-12-17 20:48 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-15 10:02 [RFC] server's statd and lockd will not sync after its nfslock restart Mi Jinlong
2009-12-15 12:41 ` J. Bruce Fields
2009-12-16 9:46 ` Mi Jinlong
2009-12-15 15:10 ` Chuck Lever
2009-12-16 10:27 ` Mi Jinlong
2009-12-16 13:49 ` Jeff Layton
[not found] ` <20091216084902.64f722ad-9yPaYZwiELC+kQycOl6kW4xkIHaj4LzF@public.gmane.org>
2009-12-17 9:34 ` Mi Jinlong
2009-12-16 19:33 ` Chuck Lever
2009-12-17 10:07 ` Mi Jinlong
2009-12-17 16:18 ` Chuck Lever
2009-12-17 20:14 ` J. Bruce Fields
2009-12-17 20:35 ` Chuck Lever
2009-12-17 20:27 ` Trond Myklebust
2009-12-17 20:34 ` Chuck Lever
2009-12-17 20:48 ` Trond Myklebust [this message]
2009-12-17 23:14 ` Neil Brown
[not found] ` <20091218101438.48eb06a4-wvvUuzkyo1EYVZTmpyfIwg@public.gmane.org>
2009-12-18 15:18 ` Chuck Lever
2009-12-19 16:42 ` Steve Dickson
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