[PATCH 2/2] nfsd: discard client_tracking_active and instead disable laundromat_work

[NeilBrown <neil@xxxxxxxxxx>]

We currently set client_tracking_active precisely when it is safe for
laundromat_work to be scheduled.  It is possible to enable/disable
laundromat_work, so we can do that instead of having a separate flag.

Doing this avoids overloading ->state_lock with a use that is only
tangentially related to the other uses.

Signed-off-by: NeilBrown <neil@xxxxxxxxxx>
---
 fs/nfsd/netns.h     |  1 -
 fs/nfsd/nfs4state.c | 24 ++++++++++--------------
 2 files changed, 10 insertions(+), 15 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 124fe4f669aa..db292ac473c6 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -6512,12 +6512,12 @@ nfsd4_force_end_grace(struct nfsd_net *nn)
 {
 	if (!nn->client_tracking_ops)
 		return false;
-	spin_lock(&nn->client_lock);
-	if (nn->client_tracking_active) {
-		nn->grace_end_forced = true;
-		mod_delayed_work(laundry_wq, &nn->laundromat_work, 0);
-	}
-	spin_unlock(&nn->client_lock);
+	/* laundromat_work must be initialised now, though it might be disabled */
+	nn->grace_end_forced = true;
+	/* This is a no-op after nfs4_state_shutdown_net() has called
+	 * disable_delayed_work_sync()
+	 */
+	mod_delayed_work(laundry_wq, &nn->laundromat_work, 0);
 	return true;
 }
 
@@ -8840,7 +8840,6 @@ 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);
@@ -8855,6 +8854,8 @@ 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 his 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);
 
@@ -8922,9 +8923,7 @@ 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",
@@ -8973,10 +8972,7 @@ 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);
-- 
2.49.0