Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 56116C10F14 for ; Tue, 23 Apr 2019 10:57:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 20361214AE for ; Tue, 23 Apr 2019 10:57:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556017069; bh=CAEh/OqemTNM7MKV0ZJ2UfJubusChaOsNFpBv3E7WNI=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=2VXrPSqyleatvtfM8scBKtjewKQS8ZN051GSs8EyDY4/G7fVxl5P6fOBVg2VaA3rW TWUJhf3KRP6aQMBs/+KHWmiFW+wmSDwm9nFoCnCvpHYnfRRPFwvU1nxAIF6ao3McWX oTU5rDLByePA1UXIq48EjrXUYb7w/5Rr9xp+ZWC0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727168AbfDWK5s (ORCPT ); Tue, 23 Apr 2019 06:57:48 -0400 Received: from mail.kernel.org ([198.145.29.99]:43662 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726150AbfDWK5s (ORCPT ); Tue, 23 Apr 2019 06:57:48 -0400 Received: from mail-ed1-f51.google.com (mail-ed1-f51.google.com [209.85.208.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8DCBB214AE for ; Tue, 23 Apr 2019 10:57:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556017066; bh=CAEh/OqemTNM7MKV0ZJ2UfJubusChaOsNFpBv3E7WNI=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=nx1L+JJgECMkHNIggruxL+j1TKdp0bAUhbga+XqoKAfzTOo9td/D94JeA2yesnWx8 cMI+nhmsUy9T84FxWF96NIFcIXyP8SBOEg1BD4ncQs3FRAS22LHekfrESnL31sDtqj vhmDVzpznW5eOdbrTnoZb9u28n5Epz7UMTN5x704= Received: by mail-ed1-f51.google.com with SMTP id k92so12172730edc.12 for ; Tue, 23 Apr 2019 03:57:46 -0700 (PDT) X-Gm-Message-State: APjAAAXFa3ktBKHXqz/ZgjYo9xTWAKqQzTiCqDB8gdn8QyRozwX9D8cl 3VtEMRVFNGOvawiOMsXHrc8Zh7OPSaR4aHl9JJlU9A== X-Google-Smtp-Source: APXvYqz86piKmX/b3jcPNAbmbl6G7fETJeR2kHScnN1pe7g9eGjvbBVtPulMC657cSBs745RDPChea6ceVsoxVQzQC8= X-Received: by 2002:a17:906:6c0d:: with SMTP id j13mr11934196ejr.249.1556017065152; Tue, 23 Apr 2019 03:57:45 -0700 (PDT) MIME-Version: 1.0 References: <20190422163424.19402-1-jlayton@kernel.org> <20190422163424.19402-2-jlayton@kernel.org> <87wojl61s5.fsf@notabene.neil.brown.name> In-Reply-To: <87wojl61s5.fsf@notabene.neil.brown.name> From: Jeff Layton Date: Tue, 23 Apr 2019 06:57:33 -0400 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v2 1/2] nfsd: wake waiters blocked on file_lock before deleting it To: NeilBrown Cc: Bruce Fields , slawek1211@gmail.com, "open list:NFS, SUNRPC, AND..." Content-Type: text/plain; charset="UTF-8" Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org On Mon, Apr 22, 2019 at 7:47 PM NeilBrown wrote: > > On Mon, Apr 22 2019, Jeff Layton wrote: > > > After a blocked nfsd file_lock request is deleted, knfsd will send a > > callback to the client and then free the request. Commit 16306a61d3b7 > > ("fs/locks: always delete_block after waiting.") changed it such that > > locks_delete_block is always called on a request after it is awoken, > > but that patch missed fixing up blocked nfsd request handling. > > > > Call locks_delete_block on the block to wake up any locks still blocked > > on the nfsd lock request before freeing it. Some of its callers already > > do this however, so just remove those calls. > > > > URL: https://bugzilla.kernel.org/show_bug.cgi?id=203363 > > Fixes: 16306a61d3b7 ("fs/locks: always delete_block after waiting.") > > Reported-by: Slawomir Pryczek > > Cc: Neil Brown > > Cc: stable@vger.kernel.org > > Signed-off-by: Jeff Layton > > --- > > fs/nfsd/nfs4state.c | 3 +-- > > 1 file changed, 1 insertion(+), 2 deletions(-) > > > > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c > > index 6a45fb00c5fc..e87e15df2044 100644 > > --- a/fs/nfsd/nfs4state.c > > +++ b/fs/nfsd/nfs4state.c > > @@ -265,6 +265,7 @@ find_or_allocate_block(struct nfs4_lockowner *lo, struct knfsd_fh *fh, > > static void > > free_blocked_lock(struct nfsd4_blocked_lock *nbl) > > { > > + locks_delete_block(&nbl->nbl_lock); > > locks_release_private(&nbl->nbl_lock); > > Thanks for tracking this down. > > An implication of this bug and fix is that we need to be particularly > careful to make sure locks_delete_block() is called on all relevant > paths. > Can we make that easier? My first thought was to include the call in > locks_release_private, but lockd calls the two quite separately and it > certainly seems appropriate that locks_delete_block should be called > asap, but locks_release_private() can be delayed. > > Also cifs calls locks_delete_block, but never calls > locks_release_private, so it wouldn't help there. > > Looking at cifs, I think there is a call missing there too. > cifs_posix_lock_set() *doesn't* always call locks_delete_block() after > waiting. In particular, if ->can_cache_brlcks becomes true while > waiting then I don't think the behaviour is right.... though I'm not > sure it is right for other reasons. It looks like the return value > should be 1 in that case, but it'll be zero. > > But back to my question about making it easier, move the BUG_ON() > calls from locks_free_lock() into locks_release_private(). > > ?? > That sounds like a fine idea. I was thinking about putting all of the BUG_ONs there in a separate function that both spots could call, but moving them into locks_release_private should work just as well. Care to propose a patch? -- Jeff Layton