From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757521AbWK0JTc (ORCPT ); Mon, 27 Nov 2006 04:19:32 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757530AbWK0JTb (ORCPT ); Mon, 27 Nov 2006 04:19:31 -0500 Received: from nz-out-0102.google.com ([64.233.162.202]:2573 "EHLO nz-out-0102.google.com") by vger.kernel.org with ESMTP id S1757521AbWK0JTb (ORCPT ); Mon, 27 Nov 2006 04:19:31 -0500 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=GQOIRADf3Kclje092PxrHSJmWkfkFNWhP8YB7Vk2vGloF8BrxSc0ZynGCj9lqoR56/Kqf6xunVnejtvbP2fC0jil+fzYa9V29a1tzMWl7dbn/qp+E/7GnmKlcz9Mfx502OPUO6VtKylE67CsCH7tbgedJNkmr4T8yi5+8oCY0Wo= Message-ID: <9a8748490611270119pc812377veec5a4de7c27337@mail.gmail.com> Date: Mon, 27 Nov 2006 10:19:29 +0100 From: "Jesper Juhl" To: "Trond Myklebust" Subject: Re: [NFS] 2.6.17.8 - do_vfs_lock: VFS is out of sync with lock manager! Cc: "Neil Brown" , nfs@lists.sourceforge.net, "Linux Kernel Mailing List" In-Reply-To: <9a8748490611210443w7711b962u3fb35aef14746582@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <9a8748490608080739w2e14e5ceg44a7bf0a3b475704@mail.gmail.com> <17636.4462.975774.528003@cse.unsw.edu.au> <9a8748490608170258s32df0272r60c8c540e5871485@mail.gmail.com> <17641.10665.116168.867041@cse.unsw.edu.au> <1156190098.6158.109.camel@localhost> <9a8748490611210443w7711b962u3fb35aef14746582@mail.gmail.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Any chance we could get the patch below (or something similar) pushed into 2.6.19? On 21/11/06, Jesper Juhl wrote: > On 21/08/06, Trond Myklebust wrote: > > On Mon, 2006-08-21 at 13:34 +1000, Neil Brown wrote: > > > Looking in fs/nfs/file.c (at 2.6.18-rc4-mm1 if it matters, but 2.6.17 > > > is much the same) > > > > > > - do_vfs_lock is only called when the filesystem was mounted with > > > -o nolock EXCEPT > > > - If a lock request to the server in interrupted (when mounted with > > > -o intr) then do_vfs_lock is called to try to get the lock > > > locally. Normally equivalent code will be called inside > > > fs/lockd/clntproc.c when the server replies that the lock has been > > > gained. In the case of an interrupt though this doesn't happen > > > but the lock may still have happened on the server. So we record > > > locally that the lock was gained, to ensure that it gets unlocked > > > when the process exits. > > > > > > As you don't have '-o nolocks' you must be hitting the second case. > > > The lock call to the server returns -EINTR or -ERESTARTSYS and > > > do_vfs_lock is called just-in-case. > > > As this is a just-in-case call, it is quite possible that the lock is > > > held by some other process, so getting an error is entirely possible. > > > So printing the message in this case seems wrong. > > > > > > On the other hand, printing the message in any other case seems wrong > > > too, as server locking is not being used, so there is nothing to get > > > out of sync with. > > > > > > As a further complication, I don't think that in the just-in-case > > > situation that it should risk waiting for the lock. > > > Now maybe we can be sure there is a pending signal which will break > > > out of any wait (though I'm worried about -ERESTARTSYS - that doesn't > > > imply a signal does it?), but I would feel more comfortable if > > > FL_SLEEP were turned off in that path. > > > > > > So: Trond: Any obvious errors in the above? > > > Is the following patch ok? > > > > Could we instead replace it with a dprintk() that returns the value of > > "res"? That will keep it useful for debugging purposes. > > > > How about the below? > (compile tested only) > > Neil: I left your Signed-off-by line since I just modified your patch slightly. > > Since Gmail will probably mangle the inline patch, it is attached as well. > > > Signed-off-by: Neil Brown > Signed-off-by: Jesper Juhl > -- > > fs/nfs/file.c | 11 +++++++---- > 1 files changed, 7 insertions(+), 4 deletions(-) > > diff --git a/fs/nfs/file.c b/fs/nfs/file.c > index cc93865..22572af 100644 > --- a/fs/nfs/file.c > +++ b/fs/nfs/file.c > @@ -428,8 +428,8 @@ static int do_vfs_lock(struct file *file > BUG(); > } > if (res < 0) > - printk(KERN_WARNING "%s: VFS is out of sync with lock > manager!\n", > - __FUNCTION__); > + dprintk("%s: VFS is out of sync with lock manager (res > = %d)!\n", > + __FUNCTION__, res); > return res; > } > > @@ -479,10 +479,13 @@ static int do_setlk(struct file *filp, i > * we clean up any state on the server. We therefore > * record the lock call as having succeeded in order to > * ensure that locks_remove_posix() cleans it out when > - * the process exits. > + * the process exits. Make sure not to sleep if > + * someone else holds the lock. > */ > - if (status == -EINTR || status == -ERESTARTSYS) > + if (status == -EINTR || status == -ERESTARTSYS) { > + fl->fl_flags &= ~FL_SLEEP; > do_vfs_lock(filp, fl); > + } > } else > status = do_vfs_lock(filp, fl); > unlock_kernel(); > -- Jesper Juhl Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html Plain text mails only, please http://www.expita.com/nomime.html