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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B892EC433EF for ; Thu, 28 Apr 2022 02:05:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233156AbiD1CI3 (ORCPT ); Wed, 27 Apr 2022 22:08:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40290 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229506AbiD1CIZ (ORCPT ); Wed, 27 Apr 2022 22:08:25 -0400 Received: from fieldses.org (fieldses.org [IPv6:2600:3c00:e000:2f7::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F323013F5F; Wed, 27 Apr 2022 19:05:11 -0700 (PDT) Received: by fieldses.org (Postfix, from userid 2815) id 854591506; Wed, 27 Apr 2022 22:05:11 -0400 (EDT) DKIM-Filter: OpenDKIM Filter v2.11.0 fieldses.org 854591506 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fieldses.org; s=default; t=1651111511; bh=QCkmNtSPy65RomWZIe/Vs0ux8LiQsEUhiCrAcC59kC0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=kTNLtXTgfc9kocTyow1/UJ8elexj4MqVaQ7Fs5pZrWgW+YGZGI+cnqZcxk9kB+NIF omoO0prchATZ/SMuD3YiMmwr2sMgdF5JHktf/dbiQR2QtVdh0JxB1UWEWNe2lIawiY nhr6JjUwdnXDcg2hzRO+3yMImy3cFWmCaCTdyUP8= Date: Wed, 27 Apr 2022 22:05:11 -0400 From: "J. Bruce Fields" To: Dai Ngo Cc: chuck.lever@oracle.com, jlayton@redhat.com, viro@zeniv.linux.org.uk, linux-nfs@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH RFC v22 6/7] NFSD: add support for lock conflict to courteous server Message-ID: <20220428020511.GK13471@fieldses.org> References: <1651049573-29552-1-git-send-email-dai.ngo@oracle.com> <1651049573-29552-7-git-send-email-dai.ngo@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1651049573-29552-7-git-send-email-dai.ngo@oracle.com> User-Agent: Mutt/1.5.21 (2010-09-15) Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Wed, Apr 27, 2022 at 01:52:52AM -0700, Dai Ngo wrote: > This patch allows expired client with lock state to be in COURTESY > state. Lock conflict with COURTESY client is resolved by the fs/lock > code using the lm_lock_expirable and lm_expire_lock callback in the > struct lock_manager_operations. > > If conflict client is in COURTESY state, set it to EXPIRABLE and > schedule the laundromat to run immediately to expire the client. The > callback lm_expire_lock waits for the laundromat to flush its work > queue before returning to caller. > > Signed-off-by: Dai Ngo > --- > fs/nfsd/nfs4state.c | 82 +++++++++++++++++++++++++++++++++-------------------- > 1 file changed, 52 insertions(+), 30 deletions(-) > > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c > index 55ecf5da25fe..9b1134d823bb 100644 > --- a/fs/nfsd/nfs4state.c > +++ b/fs/nfsd/nfs4state.c > @@ -5705,11 +5705,31 @@ static void nfsd4_ssc_expire_umount(struct nfsd_net *nn) > } > #endif > > +/* Check if any lock belonging to this lockowner has any blockers */ > static bool > -nfs4_has_any_locks(struct nfs4_client *clp) > +nfs4_lockowner_has_blockers(struct nfs4_lockowner *lo) > +{ > + struct file_lock_context *ctx; > + struct nfs4_ol_stateid *stp; > + struct nfs4_file *nf; > + > + list_for_each_entry(stp, &lo->lo_owner.so_stateids, st_perstateowner) { > + nf = stp->st_stid.sc_file; > + ctx = nf->fi_inode->i_flctx; > + if (!ctx) > + continue; > + if (locks_owner_has_blockers(ctx, lo)) > + return true; > + } > + return false; > +} > + > +static bool > +nfs4_anylock_blockers(struct nfs4_client *clp) > { > int i; > struct nfs4_stateowner *so; > + struct nfs4_lockowner *lo; > > spin_lock(&clp->cl_lock); > for (i = 0; i < OWNER_HASH_SIZE; i++) { > @@ -5717,40 +5737,17 @@ nfs4_has_any_locks(struct nfs4_client *clp) > so_strhash) { > if (so->so_is_open_owner) > continue; > - spin_unlock(&clp->cl_lock); > - return true; > + lo = lockowner(so); > + if (nfs4_lockowner_has_blockers(lo)) { > + spin_unlock(&clp->cl_lock); > + return true; > + } > } > } > spin_unlock(&clp->cl_lock); > return false; > } > > -/* > - * place holder for now, no check for lock blockers yet > - */ > -static bool > -nfs4_anylock_blockers(struct nfs4_client *clp) > -{ > - /* not allow locks yet */ > - if (nfs4_has_any_locks(clp)) > - return true; > - /* > - * don't want to check for delegation conflict here since > - * we need the state_lock for it. The laundromat willexpire > - * COURTESY later when checking for delegation recall timeout. > - */ > - return false; > -} > - > -static bool client_has_state_tmp(struct nfs4_client *clp) > -{ > - if (((!list_empty(&clp->cl_delegations)) || > - client_has_openowners(clp)) && > - list_empty(&clp->async_copies)) > - return true; > - return false; > -} > - > static void > nfs4_get_client_reaplist(struct nfsd_net *nn, struct list_head *reaplist, > struct laundry_time *lt) > @@ -5767,7 +5764,7 @@ nfs4_get_client_reaplist(struct nfsd_net *nn, struct list_head *reaplist, > goto exp_client; > if (!state_expired(lt, clp->cl_time)) > break; > - if (!client_has_state_tmp(clp)) > + if (!client_has_state(clp)) > goto exp_client; > cour = (clp->cl_state == NFSD4_COURTESY); > if (cour && ktime_get_boottime_seconds() >= > @@ -6722,6 +6719,28 @@ nfsd4_lm_put_owner(fl_owner_t owner) > nfs4_put_stateowner(&lo->lo_owner); > } > > +/* return pointer to struct nfs4_client if client is expirable */ > +static void * > +nfsd4_lm_lock_expirable(struct file_lock *cfl) > +{ > + struct nfs4_lockowner *lo = (struct nfs4_lockowner *)cfl->fl_owner; > + struct nfs4_client *clp = lo->lo_owner.so_client; > + > + if (!try_to_expire_client(clp)) > + return clp; > + return NULL; > +} > + > +/* schedule laundromat to run immediately and wait for it to complete */ > +static void > +nfsd4_lm_expire_lock(void *data) > +{ > + struct nfs4_client *clp = (struct nfs4_client *)data; > + struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id); > + > + flush_workqueue(laundry_wq); Note we don't actually end up using the nfsd_net, or the argument to lm_lock_expirable. This was a mistake in my original sketch. See https://lore.kernel.org/linux-nfs/20220417190727.GA18120@fieldses.org/ "Correction: I forgot that the laundromat is global, not per-net. So, we can skip the put_net/get_net. Also, lm_lock_expirable can just return bool instead of void *, and lm_expire_lock needs no arguments." --b. > +} > + > static void > nfsd4_lm_notify(struct file_lock *fl) > { > @@ -6748,9 +6767,12 @@ nfsd4_lm_notify(struct file_lock *fl) > } > > static const struct lock_manager_operations nfsd_posix_mng_ops = { > + .lm_mod_owner = THIS_MODULE, > .lm_notify = nfsd4_lm_notify, > .lm_get_owner = nfsd4_lm_get_owner, > .lm_put_owner = nfsd4_lm_put_owner, > + .lm_lock_expirable = nfsd4_lm_lock_expirable, > + .lm_expire_lock = nfsd4_lm_expire_lock, > }; > > static inline void > -- > 2.9.5