nfsd-6.19 fixes:

A set of NFSD fixes that arrived after the 6.19 merge window.
 
 Issues that need expedient stable backports:
 - Remove an invalid NFS status code
 - Fix an fstests failure when using pNFS
 - Fix a UAF in v4_end_grace()
 - Fix the administrative interface used to revoke NFSv4 state
 - Fix a memory leak reported by syzbot
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Merge tag 'nfsd-6.19-3' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux

Pull nfsd fixes from Chuck Lever:
 "A set of NFSD fixes for stable that arrived after the merge window:

   - Remove an invalid NFS status code

   - Fix an fstests failure when using pNFS

   - Fix a UAF in v4_end_grace()

   - Fix the administrative interface used to revoke NFSv4 state

   - Fix a memory leak reported by syzbot"

* tag 'nfsd-6.19-3' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux:
  NFSD: net ref data still needs to be freed even if net hasn't startup
  nfsd: check that server is running in unlock_filesystem
  nfsd: use correct loop termination in nfsd4_revoke_states()
  nfsd: provide locking for v4_end_grace
  NFSD: Fix permission check for read access to executable-only files
  NFSD: Remove NFSERR_EAGAIN

fs/nfs_common/common.c

@@ -17,7 +17,6 @@ static const struct {
 	{ NFSERR_NOENT,		-ENOENT		},
 	{ NFSERR_IO,		-EIO		},
 	{ NFSERR_NXIO,		-ENXIO		},
-/*	{ NFSERR_EAGAIN,	-EAGAIN		}, */
 	{ NFSERR_ACCES,		-EACCES		},
 	{ NFSERR_EXIST,		-EEXIST		},
 	{ NFSERR_XDEV,		-EXDEV		},

fs/nfsd/netns.h

@@ -66,6 +66,8 @@ 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;

fs/nfsd/nfs4proc.c

@@ -1502,7 +1502,7 @@ try_again:
 					(schedule_timeout(20*HZ) == 0)) {
 				finish_wait(&nn->nfsd_ssc_waitq, &wait);
 				kfree(work);
-				return nfserr_eagain;
+				return nfserr_jukebox;
 			}
 			finish_wait(&nn->nfsd_ssc_waitq, &wait);
 			goto try_again;

fs/nfsd/nfs4state.c

@@ -84,7 +84,7 @@ static u64 current_sessionid = 1;
 /* forward declarations */
 static bool check_for_locks(struct nfs4_file *fp, struct nfs4_lockowner *lowner);
 static void nfs4_free_ol_stateid(struct nfs4_stid *stid);
-void nfsd4_end_grace(struct nfsd_net *nn);
+static void nfsd4_end_grace(struct nfsd_net *nn);
 static void _free_cpntf_state_locked(struct nfsd_net *nn, struct nfs4_cpntf_state *cps);
 static void nfsd4_file_hash_remove(struct nfs4_file *fi);
 static void deleg_reaper(struct nfsd_net *nn);
@@ -1759,7 +1759,7 @@ static struct nfs4_stid *find_one_sb_stid(struct nfs4_client *clp,
 
 /**
  * nfsd4_revoke_states - revoke all nfsv4 states associated with given filesystem
- * @net:  used to identify instance of nfsd (there is one per net namespace)
+ * @nn:   used to identify instance of nfsd (there is one per net namespace)
  * @sb:   super_block used to identify target filesystem
  *
  * All nfs4 states (open, lock, delegation, layout) held by the server instance
@@ -1771,16 +1771,15 @@ static struct nfs4_stid *find_one_sb_stid(struct nfs4_client *clp,
  * The clients which own the states will subsequently being notified that the
  * states have been "admin-revoked".
  */
-void nfsd4_revoke_states(struct net *net, struct super_block *sb)
+void nfsd4_revoke_states(struct nfsd_net *nn, struct super_block *sb)
 {
-	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 	unsigned int idhashval;
 	unsigned int sc_types;
 
 	sc_types = SC_TYPE_OPEN | SC_TYPE_LOCK | SC_TYPE_DELEG | SC_TYPE_LAYOUT;
 
 	spin_lock(&nn->client_lock);
-	for (idhashval = 0; idhashval < CLIENT_HASH_MASK; idhashval++) {
+	for (idhashval = 0; idhashval < CLIENT_HASH_SIZE; idhashval++) {
 		struct list_head *head = &nn->conf_id_hashtbl[idhashval];
 		struct nfs4_client *clp;
 	retry:
@@ -6570,7 +6569,7 @@ nfsd4_renew(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	return nfs_ok;
 }
 
-void
+static void
 nfsd4_end_grace(struct nfsd_net *nn)
 {
 	/* do nothing if grace period already ended */
@@ -6603,6 +6602,33 @@ nfsd4_end_grace(struct nfsd_net *nn)
 	 */
 }
 
+/**
+ * nfsd4_force_end_grace - forcibly end the NFSv4 grace period
+ * @nn: network namespace for the server instance to be updated
+ *
+ * Forces bypass of normal grace period completion, then schedules
+ * the laundromat to end the grace period immediately. Does not wait
+ * for the grace period to fully terminate before returning.
+ *
+ * Return values:
+ *   %true: Grace termination schedule
+ *   %false: No action was taken
+ */
+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);
+		return false;
+	}
+	WRITE_ONCE(nn->grace_end_forced, true);
+	mod_delayed_work(laundry_wq, &nn->laundromat_work, 0);
+	spin_unlock(&nn->client_lock);
+	return true;
+}
+
 /*
  * If we've waited a lease period but there are still clients trying to
  * reclaim, wait a little longer to give them a chance to finish.
@@ -6612,6 +6638,8 @@ static bool clients_still_reclaiming(struct nfsd_net *nn)
 	time64_t double_grace_period_end = nn->boot_time +
 					   2 * nn->nfsd4_lease;
 
+	if (READ_ONCE(nn->grace_end_forced))
+		return false;
 	if (nn->track_reclaim_completes &&
 			atomic_read(&nn->nr_reclaim_complete) ==
 			nn->reclaim_str_hashtbl_size)
@@ -8932,6 +8960,8 @@ static int nfs4_state_create_net(struct net *net)
 	nn->unconf_name_tree = RB_ROOT;
 	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);
@@ -9012,6 +9042,10 @@ nfs4_state_start_net(struct net *net)
 		return ret;
 	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);
 	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",
@@ -9060,6 +9094,9 @@ 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);
 	locks_end_grace(&nn->nfsd4_manager);
 

fs/nfsd/nfsctl.c

@@ -259,6 +259,7 @@ static ssize_t write_unlock_fs(struct file *file, char *buf, size_t size)
 	struct path path;
 	char *fo_path;
 	int error;
+	struct nfsd_net *nn;
 
 	/* sanity check */
 	if (size == 0)
@@ -285,7 +286,13 @@ static ssize_t write_unlock_fs(struct file *file, char *buf, size_t size)
 	 * 3.  Is that directory the root of an exported file system?
 	 */
 	error = nlmsvc_unlock_all_by_sb(path.dentry->d_sb);
-	nfsd4_revoke_states(netns(file), path.dentry->d_sb);
+	mutex_lock(&nfsd_mutex);
+	nn = net_generic(netns(file), nfsd_net_id);
+	if (nn->nfsd_serv)
+		nfsd4_revoke_states(nn, path.dentry->d_sb);
+	else
+		error = -EINVAL;
+	mutex_unlock(&nfsd_mutex);
 
 	path_put(&path);
 	return error;
@@ -1082,10 +1089,9 @@ static ssize_t write_v4_end_grace(struct file *file, char *buf, size_t size)
 		case 'Y':
 		case 'y':
 		case '1':
-			if (!nn->nfsd_serv)
+			if (!nfsd4_force_end_grace(nn))
 				return -EBUSY;
 			trace_nfsd_end_grace(netns(file));
-			nfsd4_end_grace(nn);
 			break;
 		default:
 			return -EINVAL;

fs/nfsd/nfsd.h

@@ -233,7 +233,6 @@ void		nfsd_lockd_shutdown(void);
 #define	nfserr_noent		cpu_to_be32(NFSERR_NOENT)
 #define	nfserr_io		cpu_to_be32(NFSERR_IO)
 #define	nfserr_nxio		cpu_to_be32(NFSERR_NXIO)
-#define	nfserr_eagain		cpu_to_be32(NFSERR_EAGAIN)
 #define	nfserr_acces		cpu_to_be32(NFSERR_ACCES)
 #define	nfserr_exist		cpu_to_be32(NFSERR_EXIST)
 #define	nfserr_xdev		cpu_to_be32(NFSERR_XDEV)

fs/nfsd/nfssvc.c

@@ -406,26 +406,26 @@ static void nfsd_shutdown_net(struct net *net)
 {
 	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 
-	if (!nn->nfsd_net_up)
-		return;
+	if (nn->nfsd_net_up) {
+		percpu_ref_kill_and_confirm(&nn->nfsd_net_ref, nfsd_net_done);
+		wait_for_completion(&nn->nfsd_net_confirm_done);
 
-	percpu_ref_kill_and_confirm(&nn->nfsd_net_ref, nfsd_net_done);
-	wait_for_completion(&nn->nfsd_net_confirm_done);
-
-	nfsd_export_flush(net);
-	nfs4_state_shutdown_net(net);
-	nfsd_reply_cache_shutdown(nn);
-	nfsd_file_cache_shutdown_net(net);
-	if (nn->lockd_up) {
-		lockd_down(net);
-		nn->lockd_up = false;
+		nfsd_export_flush(net);
+		nfs4_state_shutdown_net(net);
+		nfsd_reply_cache_shutdown(nn);
+		nfsd_file_cache_shutdown_net(net);
+		if (nn->lockd_up) {
+			lockd_down(net);
+			nn->lockd_up = false;
+		}
+		wait_for_completion(&nn->nfsd_net_free_done);
 	}
 
-	wait_for_completion(&nn->nfsd_net_free_done);
 	percpu_ref_exit(&nn->nfsd_net_ref);
 
+	if (nn->nfsd_net_up)
+		nfsd_shutdown_generic();
 	nn->nfsd_net_up = false;
-	nfsd_shutdown_generic();
 }
 
 static DEFINE_SPINLOCK(nfsd_notifier_lock);

fs/nfsd/state.h

@@ -841,15 +841,15 @@ static inline void get_nfs4_file(struct nfs4_file *fi)
 struct nfsd_file *find_any_file(struct nfs4_file *f);
 
 #ifdef CONFIG_NFSD_V4
-void nfsd4_revoke_states(struct net *net, struct super_block *sb);
+void nfsd4_revoke_states(struct nfsd_net *nn, struct super_block *sb);
 #else
-static inline void nfsd4_revoke_states(struct net *net, struct super_block *sb)
+static inline void nfsd4_revoke_states(struct nfsd_net *nn, struct super_block *sb)
 {
 }
 #endif
 
 /* grace period management */
-void nfsd4_end_grace(struct nfsd_net *nn);
+bool nfsd4_force_end_grace(struct nfsd_net *nn);
 
 /* nfs4recover operations */
 extern int nfsd4_client_tracking_init(struct net *net);

fs/nfsd/vfs.c

@@ -2865,8 +2865,8 @@ nfsd_permission(struct svc_cred *cred, struct svc_export *exp,
 
 	/* Allow read access to binaries even when mode 111 */
 	if (err == -EACCES && S_ISREG(inode->i_mode) &&
-	     (acc == (NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE) ||
-	      acc == (NFSD_MAY_READ | NFSD_MAY_READ_IF_EXEC)))
+	     (((acc & NFSD_MAY_MASK) == NFSD_MAY_READ) &&
+	      (acc & (NFSD_MAY_OWNER_OVERRIDE | NFSD_MAY_READ_IF_EXEC))))
 		err = inode_permission(&nop_mnt_idmap, inode, MAY_EXEC);
 
 	return err? nfserrno(err) : 0;

include/trace/misc/nfs.h

@@ -16,7 +16,6 @@ TRACE_DEFINE_ENUM(NFSERR_PERM);
 TRACE_DEFINE_ENUM(NFSERR_NOENT);
 TRACE_DEFINE_ENUM(NFSERR_IO);
 TRACE_DEFINE_ENUM(NFSERR_NXIO);
-TRACE_DEFINE_ENUM(NFSERR_EAGAIN);
 TRACE_DEFINE_ENUM(NFSERR_ACCES);
 TRACE_DEFINE_ENUM(NFSERR_EXIST);
 TRACE_DEFINE_ENUM(NFSERR_XDEV);
@@ -52,7 +51,6 @@ TRACE_DEFINE_ENUM(NFSERR_JUKEBOX);
 		{ NFSERR_NXIO,			"NXIO" }, \
 		{ ECHILD,			"CHILD" }, \
 		{ ETIMEDOUT,			"TIMEDOUT" }, \
-		{ NFSERR_EAGAIN,		"AGAIN" }, \
 		{ NFSERR_ACCES,			"ACCES" }, \
 		{ NFSERR_EXIST,			"EXIST" }, \
 		{ NFSERR_XDEV,			"XDEV" }, \

include/uapi/linux/nfs.h

@@ -49,7 +49,6 @@
 	NFSERR_NOENT = 2,		/* v2 v3 v4 */
 	NFSERR_IO = 5,			/* v2 v3 v4 */
 	NFSERR_NXIO = 6,		/* v2 v3 v4 */
-	NFSERR_EAGAIN = 11,		/* v2 v3 */
 	NFSERR_ACCES = 13,		/* v2 v3 v4 */
 	NFSERR_EXIST = 17,		/* v2 v3 v4 */
 	NFSERR_XDEV = 18,		/*    v3 v4 */