From mboxrd@z Thu Jan 1 00:00:00 1970 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=-11.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 8ADDCC43461 for ; Fri, 4 Sep 2020 22:01:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F16F72083B for ; Fri, 4 Sep 2020 22:01:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fieldses.org header.i=@fieldses.org header.b="VP40/OqM" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727990AbgIDWBJ (ORCPT ); Fri, 4 Sep 2020 18:01:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45190 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727057AbgIDWBI (ORCPT ); Fri, 4 Sep 2020 18:01:08 -0400 Received: from fieldses.org (fieldses.org [IPv6:2600:3c00:e000:2f7::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CF120C061244 for ; Fri, 4 Sep 2020 15:01:08 -0700 (PDT) Received: by fieldses.org (Postfix, from userid 2815) id C18E36EEB; Fri, 4 Sep 2020 18:01:04 -0400 (EDT) DKIM-Filter: OpenDKIM Filter v2.11.0 fieldses.org C18E36EEB DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fieldses.org; s=default; t=1599256864; bh=zY5P2L/P0iOF9UtqYYHbkfouQUqmjkH5sBNxhzajB38=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=VP40/OqMJWKC6LUqMPgai/ti67nP1nX4RYvs+PW/+nnzQyUwiLXviWacqV0Kl1Xhi t1qSasMdvxI+gLm5mVverBYYq3EOL6f+lO3kmryVuSxyIopgql9TIE47dO/+xK5Byo lMycGinwkO5XA1tAxhOszhB6sul5GwpduBmGl29U= Date: Fri, 4 Sep 2020 18:01:04 -0400 From: Bruce Fields To: Chuck Lever Cc: Jeff Layton , Linux NFS Mailing List Subject: Re: still seeing single client NFS4ERR_DELAY / CB_RECALL Message-ID: <20200904220104.GA7212@fieldses.org> References: <00CAA5B7-418E-4AB5-AE08-FE2F87B06795@oracle.com> <20200810201001.GC13266@fieldses.org> <20200817222034.GA6390@fieldses.org> <20200819212927.GB30476@fieldses.org> <5D346E9E-C7C5-49F7-9694-8DD98AF1149A@oracle.com> <20200824142237.GA29837@fieldses.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org On Mon, Aug 24, 2020 at 11:42:18AM -0400, Chuck Lever wrote: > > > > On Aug 24, 2020, at 10:22 AM, Bruce Fields wrote: > > > > On Mon, Aug 24, 2020 at 09:39:31AM -0400, Chuck Lever wrote: > >> > >> > >>> On Aug 19, 2020, at 5:29 PM, Bruce Fields wrote: > >>> > >>> On Tue, Aug 18, 2020 at 05:26:26PM -0400, Chuck Lever wrote: > >>>> > >>>>> On Aug 17, 2020, at 6:20 PM, Bruce Fields wrote: > >>>>> > >>>>> On Sun, Aug 16, 2020 at 04:46:00PM -0400, Chuck Lever wrote: > >>>>> > >>>>>> In order of application: > >>>>>> > >>>>>> 5920afa3c85f ("nfsd: hook nfsd_commit up to the nfsd_file cache") > >>>>>> 961.68user 5252.40system 20:12.30elapsed 512%CPU, 2541 DELAY errors > >>>>>> These results are similar to v5.3. > >>>>>> > >>>>>> fd4f83fd7dfb ("nfsd: convert nfs4_file->fi_fds array to use nfsd_files") > >>>>>> Does not build > >>>>>> > >>>>>> eb82dd393744 ("nfsd: convert fi_deleg_file and ls_file fields to nfsd_file") > >>>>>> 966.92user 5425.47system 33:52.79elapsed 314%CPU, 1330 DELAY errors > >>>>>> > >>>>>> Can you take a look and see if there's anything obvious? > >>>>> > >>>>> Unfortunately nothing about the file cache code is very obvious to me. > >>>>> I'm looking at it.... > >>>>> > >>>>> It adds some new nfserr_jukebox returns in nfsd_file_acquire. Those > >>>>> mostly look like kmalloc failures, the one I'm not sure about is the > >>>>> NFSD_FILE_HASHED check. > >>>>> > >>>>> Or maybe it's the lease break there. > >>>> > >>>> nfsd_file_acquire() always calls fh_verify() before it invokes nfsd_open(). > >>>> Replacing nfs4_get_vfs_file's nfsd_open() call with nfsd_file_acquire() adds > >>>> almost 10 million fh_verify() calls to my test run. > >>> > >>> Checking out the code as of fd4f83fd7dfb.... > >>> > >>> nfsd_file_acquire() calls nfsd_open_verified(). > >>> > >>> And nfsd_open() is basically just fh_verify()+nfsd_open_verified(). > >>> > >>> So it doesn't look like the replacement of nfsd_open() by > >>> nfsd_file_acquire() should have changed the number of fh_verify() calls. > >> > >> I see a lot more vfs_setlease() failures after fd4f83fd7dfb. > >> check_conflicting_open() fails because "inode is open for write": > >> > >> 1780 if (arg == F_RDLCK) > >> 1781 return inode_is_open_for_write(inode) ? -EAGAIN : 0; > >> > >> The behavior on the wire is that the server simply doesn't hand out > >> many delegations. > >> > >> NFSv4 OPEN uses nfsd_file_acquire() now, but I don't see CLOSE > >> releasing the cached file descriptor. Wouldn't that cached > >> descriptor conflict with subsequent OPENs? > > > > Could be, yes. > > > > That also reminds me of this patch, did I already send it to you? > > I don't have this one. I can try it. No difference, I take it? There could also be something wrong with nfsd4_check_conflicting_opens() that's preventing delegations when it shouldn't. There might also be some way fh_verify() could be smarter. There's a big comment there explaining why we repeat the permission checks each time, but maybe we could keep a flag somewhere that tracks whether we really need to call nfsd_setuser again. Based on your and Frank's experiences I'm also sympathetic to the idea that maybe the filehandle cache just gets in the way in the v4 case. --b. > > Author: J. Bruce Fields > > Date: Fri Jul 17 18:54:54 2020 -0400 > > > > nfsd: Cache R, RW, and W opens separately > > > > The nfsd open code has always kept separate read-only, read-write, and > > write-only opens as necessary to ensure that when a client closes or > > downgrades, we don't retain more access than necessary. > > > > Honestly, I'm not sure if that's completely necessary, but I'd rather > > stick to that behavior. > > > > Signed-off-by: J. Bruce Fields > > > > diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c > > index 82198d747c4c..4b6f70e0d987 100644 > > --- a/fs/nfsd/filecache.c > > +++ b/fs/nfsd/filecache.c > > @@ -891,7 +891,7 @@ nfsd_file_find_locked(struct inode *inode, unsigned int may_flags, > > > > hlist_for_each_entry_rcu(nf, &nfsd_file_hashtbl[hashval].nfb_head, > > nf_node, lockdep_is_held(&nfsd_file_hashtbl[hashval].nfb_lock)) { > > - if ((need & nf->nf_may) != need) > > + if (nf->nf_may != need) > > continue; > > if (nf->nf_inode != inode) > > continue; > > -- > Chuck Lever > >