linux-kernel - Re: major NFSv4 client regression (-rc7)

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Date:	Thu, 10 Jan 2008 15:51:34 -0500
From:	Trond Myklebust <Trond.Myklebust@...app.com>
To:	Jeff Garzik <jeff@...zik.org>
Cc:	linux-nfs@...r.kernel.org, linux-kernel@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: major NFSv4 client regression (-rc7)


On Thu, 2008-01-10 at 15:41 -0500, Jeff Garzik wrote:
> Server:		Linux 2.6.24-rc6 (x86-64/Fedora 8)
> Good client:	Linux 2.6.24-rc6-ge697789d (x86-64/Fedora 7)
> Bad client:	Linux 2.6.24-rc7-gfd0b45df (x86-64/Fedora 7)
> Situation:	home dir via NFS
> 
> My home setup is a standard homedir-over-NFS setup, using NFSv4 on both
> client and server.  I just rebooted into the latest upstream kernel, and
> I am getting NFS client hangs all over the place:
> 
> 	[jgarzik@...e firefox]$ cat profiles.ini 
> 
> 	hangs here, for 15 minutes so far and counting...
> 	('core' is the client machine)
> 
> and I first noticed this when firefox and thunderbird were hanging, when
> I tried to start them after rebooting into the latest kernel.  stracing
> firefox yielding a hang in open:
> 
> 	("/g" is the NFS-mounted volume)
> 
> 	access("/usr/lib64/firefox-2.0.0.10/updates", F_OK) = -1 ENOENT (No such file or directory)
> 	access("/g/g/.mozilla/firefox", F_OK)   = 0
> 	access("/g/g/.mozilla/firefox", F_OK)   = 0
> 	stat("/g/g/.mozilla/firefox/profiles.ini", {st_mode=S_IFREG|0664, st_size=94, ...}) = 0
> 	open("/g/g/.mozilla/firefox/profiles.ini", O_RDONLY
> 
> 	hangs here, for 20 minutes so far and counting...
> 
> As you can see from the trace, and as I can report simply by being able
> to send this message, SOME file accesses over NFS work just fine.
> 
> Accessing the file works when logged into the server, so its not disk
> corruption or something like that.
> 
> Neither client nor server have anything interesting in dmesg -- in fact
> nothing in dmesg beyond the normal boot messages have been printed.
> 
> Let me know what info I can provide...  This is a 100% reproducible
> regression, and this latest NFS client revision has made my local
> NFS-over-homedir setup completely unusable.  I am forced to return to
> the known working client (Linux 2.6.24-rc6-ge697789d) just to run basic
> apps.

This looks as if it might be the same issue that was reported as bug
9712 in bugzilla (http://bugzilla.kernel.org/show_bug.cgi?id=9712).

The fix is attached. Please could you confirm that it fixes the hang?

Cheers
  Trond

Download attachment "linux-2.6.24-001-fix_locking_deadlock_in_nfs4_lock_prepare.dif" of type "message/rfc822" (1570 bytes)