From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 783C02EC0A2 for ; Sat, 13 Dec 2025 18:42:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765651333; cv=none; b=ckM0wDJPQKVt6ftgfKa9VbBC25+Kq4MiIYp+0v82RXjtzUYU3RtP5VLpne1UCjkgimbWhYS7ijGKHFPs7w+2kI4owlOFVD8JoTdafxKuhrr39T/nsartwLEC6ckUewsHqYUwjO1B47thCLw+oUVgI0fBZIyf9j+A7NfibT5gA/o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765651333; c=relaxed/simple; bh=5TgVQM7q8UyqhymSAm5TFDQJvkw6s4k4lfnXRiLAWDE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=LOf0thaw0kAFuYrsCYfNEX1F/rkL20KqLS8ihnUm6Doh1HZDgEJzYnCZFKpt2AZtgFvuqAlAYbj0A6fUcfemVi+T1xpKekO9e+D2APpaYMR7m5uSv9+Bpo/aZhjJ21QCj+xzg+kEXemyptbLBlIDuJGsnmRlUt+i9L85LGEFFdc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bA+5WqOC; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="bA+5WqOC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 27E8CC4AF09; Sat, 13 Dec 2025 18:42:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1765651332; bh=5TgVQM7q8UyqhymSAm5TFDQJvkw6s4k4lfnXRiLAWDE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bA+5WqOCdWwyY44HQEOx1LwzweGzAGnmzWARksOFOBnqJEl20akSgpbrAgXUDKMLU Q/2JdjtlTaljyrrA4Z1sJdx5GALXGKrDHND/Y/rMLymRujBGs2K8b1KvrsfV1BROXO guvP5wBqwzYBDquhJ6pzf2vUUX5Tjd7AobYKuU0d1F7V4K91EVkK6O92iFza1OGy2D iEbeGcpdM5NqqZgiUFFTZu53GSVj/Le7+Q7nS8tQZr2jleggZv0MWtpTBklJbqCuX5 9zzMvGkGZYT/YXWDh5lReVNlo790hbyMvTfRGH4o4utNF2gsA/sV6crgr9MGdmOT5z tkXcmlToKj0sg== From: Chuck Lever To: NeilBrown , Jeff Layton , Olga Kornievskaia , Dai Ngo , Tom Talpey Cc: , lilingfeng3@huawei.com, yangerkun@huawei.com, yi.zhang@huawei.com, houtao1@huawei.com, chengzhihao1@huawei.com, yukuai3@huawei.com Subject: [PATCH v3 2/2] nfsd: use workqueue enable/disable APIs for v4_end_grace sync Date: Sat, 13 Dec 2025 13:42:00 -0500 Message-ID: <20251213184200.585652-3-cel@kernel.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20251213184200.585652-1-cel@kernel.org> References: <20251213184200.585652-1-cel@kernel.org> Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: NeilBrown "nfsd: provide locking for v4_end_grace" introduced a client_tracking_active flag protected by nn->client_lock to prevent the laundromat from being scheduled before client tracking initialization or after shutdown begins. That commit is suitable for backporting to LTS kernels that predate commit 86898fa6b8cd ("workqueue: Implement disable/enable for (delayed) work items"). However, the workqueue subsystem in recent kernels provides enable_delayed_work() and disable_delayed_work_sync() for this purpose. Using this mechanism enable us to remove the client_tracking_active flag and associated spinlock operations while preserving the same synchronization guarantees, which is a cleaner long-term approach. Signed-off-by: NeilBrown Signed-off-by: Chuck Lever --- fs/nfsd/netns.h | 1 - fs/nfsd/nfs4state.c | 22 +++++++++------------- 2 files changed, 9 insertions(+), 14 deletions(-) diff --git a/fs/nfsd/netns.h b/fs/nfsd/netns.h index fe8338735e7c..d83c68872c4c 100644 --- a/fs/nfsd/netns.h +++ b/fs/nfsd/netns.h @@ -67,7 +67,6 @@ struct nfsd_net { struct lock_manager nfsd4_manager; bool grace_ended; bool grace_end_forced; - bool client_tracking_active; time64_t boot_time; struct dentry *nfsd_client_dir; diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index 1d307cc533d9..c9be724c48d0 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -6619,14 +6619,14 @@ bool nfsd4_force_end_grace(struct nfsd_net *nn) { if (!nn->client_tracking_ops) return false; - spin_lock(&nn->client_lock); - if (nn->grace_ended || !nn->client_tracking_active) { - spin_unlock(&nn->client_lock); + if (READ_ONCE(nn->grace_ended)) return false; - } + /* laundromat_work must be initialised now, though it might be disabled */ WRITE_ONCE(nn->grace_end_forced, true); + /* mod_delayed_work() doesn't queue work after + * nfs4_state_shutdown_net() has called disable_delayed_work_sync() + */ mod_delayed_work(laundry_wq, &nn->laundromat_work, 0); - spin_unlock(&nn->client_lock); return true; } @@ -8962,7 +8962,6 @@ static int nfs4_state_create_net(struct net *net) nn->boot_time = ktime_get_real_seconds(); nn->grace_ended = false; nn->grace_end_forced = false; - nn->client_tracking_active = false; nn->nfsd4_manager.block_opens = true; INIT_LIST_HEAD(&nn->nfsd4_manager.list); INIT_LIST_HEAD(&nn->client_lru); @@ -8977,6 +8976,8 @@ static int nfs4_state_create_net(struct net *net) INIT_LIST_HEAD(&nn->blocked_locks_lru); INIT_DELAYED_WORK(&nn->laundromat_work, laundromat_main); + /* Make sure this cannot run until client tracking is initialised */ + disable_delayed_work(&nn->laundromat_work); INIT_WORK(&nn->nfsd_shrinker_work, nfsd4_state_shrinker_worker); get_net(net); @@ -9044,9 +9045,7 @@ nfs4_state_start_net(struct net *net) locks_start_grace(net, &nn->nfsd4_manager); nfsd4_client_tracking_init(net); /* safe for laundromat to run now */ - spin_lock(&nn->client_lock); - nn->client_tracking_active = true; - spin_unlock(&nn->client_lock); + enable_delayed_work(&nn->laundromat_work); if (nn->track_reclaim_completes && nn->reclaim_str_hashtbl_size == 0) goto skip_grace; printk(KERN_INFO "NFSD: starting %lld-second grace period (net %x)\n", @@ -9095,10 +9094,7 @@ nfs4_state_shutdown_net(struct net *net) shrinker_free(nn->nfsd_client_shrinker); cancel_work_sync(&nn->nfsd_shrinker_work); - spin_lock(&nn->client_lock); - nn->client_tracking_active = false; - spin_unlock(&nn->client_lock); - cancel_delayed_work_sync(&nn->laundromat_work); + disable_delayed_work_sync(&nn->laundromat_work); locks_end_grace(&nn->nfsd4_manager); INIT_LIST_HEAD(&reaplist); -- 2.52.0