From 27e383ddeb3c88e20874c545285f2dce1a98f56a Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Sat, 13 Dec 2025 13:42:00 -0500 Subject: [PATCH] nfsd: use workqueue enable/disable APIs for v4_end_grace sync "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 Tested-by: Li Lingfeng Reviewed-by: Jeff Layton 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 fe8338735e7cc..d83c68872c4c3 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 96e19817cd6bb..4a896c7b494fc 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -6637,14 +6637,14 @@ 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; } @@ -8980,7 +8980,6 @@ 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); @@ -8995,6 +8994,8 @@ 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); @@ -9062,9 +9063,7 @@ 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", @@ -9113,10 +9112,7 @@ 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); -- 2.47.3