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nfsd: use workqueue enable/disable APIs for v4_end_grace sync

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"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 86898fa6b8
("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 <neil@brown.name>
Tested-by: Li Lingfeng <lilingfeng3@huawei.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
This commit is contained in:
NeilBrown 2025-12-13 13:42:00 -05:00 • committed by Chuck Lever
parent 0ac903d1bf
commit 27e383ddeb
2 changed files with 9 additions and 14 deletions
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1
fs/nfsd/netns.h
View file

@ -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;

22
fs/nfsd/nfs4state.c
View file

@ -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);