nfsd: support for lifting grace period early

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new file mode 100644
index 000000000000..2257a1311027
@@ -0,0 +1,28 @@
+/*
+ * Procfs support for lockd
+ *
+ * Copyright (c) 2014 Jeff Layton <[email protected]>
+ */
+#ifndef _LOCKD_PROCFS_H
+#define _LOCKD_PROCFS_H
+
+#include <linux/kconfig.h>
+
+#if IS_ENABLED(CONFIG_PROC_FS)
+int lockd_create_procfs(void);
+void lockd_remove_procfs(void);
+#else
+static inline int
+lockd_create_procfs(void)
+{
+	return 0;
+}
+
+static inline void
+lockd_remove_procfs(void)
+{
+	return;
+}
+#endif /* IS_ENABLED(CONFIG_PROC_FS) */
+
+#endif /* _LOCKD_PROCFS_H */

index 8f27c93f8d2e..21223f15c00e 100644
@@ -36,6 +36,7 @@
 #include <linux/nfs.h>
 
 #include "netns.h"
+#include "procfs.h"
 
 #define NLMDBG_FACILITY		NLMDBG_SVC
 #define LOCKD_BUFSIZE		(1024 + NLMSVC_XDRSIZE)

@@ -617,8 +618,15 @@ static int __init init_nlm(void)
 	err = register_pernet_subsys(&lockd_net_ops);
 	if (err)
 		goto err_pernet;
+
+	err = lockd_create_procfs();
+	if (err)
+		goto err_procfs;
+
 	return 0;
 
+err_procfs:
+	unregister_pernet_subsys(&lockd_net_ops);
 err_pernet:
 #ifdef CONFIG_SYSCTL
 	unregister_sysctl_table(nlm_sysctl_table);

@@ -631,6 +639,7 @@ static void __exit exit_nlm(void)
 {
 	/* FIXME: delete all NLM clients */
 	nlm_shutdown_hosts();
+	lockd_remove_procfs();
 	unregister_pernet_subsys(&lockd_net_ops);
 #ifdef CONFIG_SYSCTL
 	unregister_sysctl_table(nlm_sysctl_table);

index 5c5873811bd9..de6bea769b24 100644
@@ -4123,7 +4123,7 @@ out:
 	return status;
 }
 
-static void
+void
 nfsd4_end_grace(struct nfsd_net *nn)
 {
 	/* do nothing if grace period already ended */

index 4e042105fb6e..99044e237861 100644
@@ -49,6 +49,7 @@ enum {
 	NFSD_Leasetime,
 	NFSD_Gracetime,
 	NFSD_RecoveryDir,
+	NFSD_V4EndGrace,
 #endif
 };
 

@@ -68,6 +69,7 @@ static ssize_t write_maxconn(struct file *file, char *buf, size_t size);
 static ssize_t write_leasetime(struct file *file, char *buf, size_t size);
 static ssize_t write_gracetime(struct file *file, char *buf, size_t size);
 static ssize_t write_recoverydir(struct file *file, char *buf, size_t size);
+static ssize_t write_v4_end_grace(struct file *file, char *buf, size_t size);
 #endif
 
 static ssize_t (*write_op[])(struct file *, char *, size_t) = {

@@ -84,6 +86,7 @@ static ssize_t (*write_op[])(struct file *, char *, size_t) = {
 	[NFSD_Leasetime] = write_leasetime,
 	[NFSD_Gracetime] = write_gracetime,
 	[NFSD_RecoveryDir] = write_recoverydir,
+	[NFSD_V4EndGrace] = write_v4_end_grace,
 #endif
 };
 

@@ -1077,6 +1080,37 @@ static ssize_t write_recoverydir(struct file *file, char *buf, size_t size)
 	return rv;
 }
 
+/**
+ * write_v4_end_grace - release grace period for nfsd's v4.x lock manager
+ *
+ * Input:
+ *			buf:		ignored
+ *			size:		zero
+ * OR
+ *
+ * Input:
+ * 			buf:		any value
+ *			size:		non-zero length of C string in @buf
+ * Output:
+ *			passed-in buffer filled with "Y" or "N" with a newline
+ *			and NULL-terminated C string. This indicates whether
+ *			the grace period has ended in the current net
+ *			namespace. Return code is the size in bytes of the
+ *			string. Writing to the file will end the grace period
+ *			for nfsd's v4 lock manager.
+ */
+static ssize_t write_v4_end_grace(struct file *file, char *buf, size_t size)
+{
+	struct net *net = file->f_dentry->d_sb->s_fs_info;
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+	if (size > 0)
+		nfsd4_end_grace(nn);
+
+	return scnprintf(buf, SIMPLE_TRANSACTION_LIMIT, "%c\n",
+			 nn->grace_ended ? 'Y' : 'N');
+}
+
 #endif
 
 /*----------------------------------------------------------------------------*/

@@ -1110,6 +1144,7 @@ static int nfsd_fill_super(struct super_block * sb, void * data, int silent)
 		[NFSD_Leasetime] = {"nfsv4leasetime", &transaction_ops, S_IWUSR|S_IRUSR},
 		[NFSD_Gracetime] = {"nfsv4gracetime", &transaction_ops, S_IWUSR|S_IRUSR},
 		[NFSD_RecoveryDir] = {"nfsv4recoverydir", &transaction_ops, S_IWUSR|S_IRUSR},
+		[NFSD_V4EndGrace] = {"v4_end_grace", &transaction_ops, S_IWUSR|S_IRUGO},
 #endif
 		/* last one */ {""}
 	};

index 4a89e00d7461..ecf579904892 100644
@@ -545,6 +545,9 @@ extern struct nfs4_client_reclaim *nfs4_client_to_reclaim(const char *name,
 							struct nfsd_net *nn);
 extern bool nfs4_has_reclaimed_state(const char *name, struct nfsd_net *nn);
 
+/* grace period management */
+void nfsd4_end_grace(struct nfsd_net *nn);
+
 /* nfs4recover operations */
 extern int nfsd4_client_tracking_init(struct net *net);
 extern void nfsd4_client_tracking_exit(struct net *net);

index 9c271f42604a..a0d2ba956a3f 100644
@@ -58,7 +58,7 @@ struct nfsd4_client_tracking_ops {
 	void (*create)(struct nfs4_client *);
 	void (*remove)(struct nfs4_client *);
 	int (*check)(struct nfs4_client *);
-	void (*grace_done)(struct nfsd_net *, time_t);
+	void (*grace_done)(struct nfsd_net *);
 };
 
 /* Globals */

@@ -392,7 +392,7 @@ purge_old(struct dentry *parent, struct dentry *child, struct nfsd_net *nn)
 }
 
 static void
-nfsd4_recdir_purge_old(struct nfsd_net *nn, time_t boot_time)
+nfsd4_recdir_purge_old(struct nfsd_net *nn)
 {
 	int status;
 

@@ -1016,7 +1016,7 @@ nfsd4_cld_check(struct nfs4_client *clp)
 }
 
 static void
-nfsd4_cld_grace_done(struct nfsd_net *nn, time_t boot_time)
+nfsd4_cld_grace_done(struct nfsd_net *nn)
 {
 	int ret;
 	struct cld_upcall *cup;

@@ -1029,7 +1029,7 @@ nfsd4_cld_grace_done(struct nfsd_net *nn, time_t boot_time)
 	}
 
 	cup->cu_msg.cm_cmd = Cld_GraceDone;
-	cup->cu_msg.cm_u.cm_gracetime = (int64_t)boot_time;
+	cup->cu_msg.cm_u.cm_gracetime = (int64_t)nn->boot_time;
 	ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_msg);
 	if (!ret)
 		ret = cup->cu_msg.cm_status;

@@ -1245,13 +1245,12 @@ nfsd4_umh_cltrack_check(struct nfs4_client *clp)
 }
 
 static void
-nfsd4_umh_cltrack_grace_done(struct nfsd_net __attribute__((unused)) *nn,
-				time_t boot_time)
+nfsd4_umh_cltrack_grace_done(struct nfsd_net *nn)
 {
 	char *legacy;
 	char timestr[22]; /* FIXME: better way to determine max size? */
 
-	sprintf(timestr, "%ld", boot_time);
+	sprintf(timestr, "%ld", nn->boot_time);
 	legacy = nfsd4_cltrack_legacy_topdir();
 	nfsd4_umh_cltrack_upcall("gracedone", timestr, legacy);
 	kfree(legacy);

@@ -1356,10 +1355,10 @@ nfsd4_client_record_check(struct nfs4_client *clp)
 }
 
 void
-nfsd4_record_grace_done(struct nfsd_net *nn, time_t boot_time)
+nfsd4_record_grace_done(struct nfsd_net *nn)
 {
 	if (nn->client_tracking_ops)
-		nn->client_tracking_ops->grace_done(nn, boot_time);
+		nn->client_tracking_ops->grace_done(nn);
 }
 
 static int

index de6bea769b24..6479c45a17c9 100644
@@ -4132,7 +4132,7 @@ nfsd4_end_grace(struct nfsd_net *nn)
 
 	dprintk("NFSD: end of grace period\n");
 	nn->grace_ended = true;
-	nfsd4_record_grace_done(nn, nn->boot_time);
+	nfsd4_record_grace_done(nn);
 	locks_end_grace(&nn->nfsd4_manager);
 	/*
 	 * Now that every NFSv4 client has had the chance to recover and

index ecf579904892..854f0c574ccf 100644
@@ -554,7 +554,7 @@ extern void nfsd4_client_tracking_exit(struct net *net);
 extern void nfsd4_client_record_create(struct nfs4_client *clp);
 extern void nfsd4_client_record_remove(struct nfs4_client *clp);
 extern int nfsd4_client_record_check(struct nfs4_client *clp);
-extern void nfsd4_record_grace_done(struct nfsd_net *nn, time_t boot_time);
+extern void nfsd4_record_grace_done(struct nfsd_net *nn);
 
 /* nfs fault injection functions */
 #ifdef CONFIG_NFSD_FAULT_INJECTION

index a0d2ba956a3f..2b61bcd92b58 100644
@@ -1062,6 +1062,8 @@ MODULE_PARM_DESC(cltrack_legacy_disable,
 
 #define LEGACY_TOPDIR_ENV_PREFIX "NFSDCLTRACK_LEGACY_TOPDIR="
 #define LEGACY_RECDIR_ENV_PREFIX "NFSDCLTRACK_LEGACY_RECDIR="
+#define CLIENT_MINORVERS_ENV_PREFIX "NFSDCLTRACK_CLIENT_MINORVERSION="
+#define GRACE_START_ENV_PREFIX "NFSDCLTRACK_GRACE_START="
 
 static char *
 nfsd4_cltrack_legacy_topdir(void)

@@ -1126,10 +1128,60 @@ nfsd4_cltrack_legacy_recdir(const struct xdr_netobj *name)
 	return result;
 }
 
+static char *
+nfsd4_cltrack_client_minorversion(struct nfs4_client *clp)
+{
+	int copied;
+	size_t len;
+	char *result;
+
+	/* prefix + max width of integer string + terminating NULL */
+	len = strlen(CLIENT_MINORVERS_ENV_PREFIX) + 10 + 1;
+
+	result = kmalloc(len, GFP_KERNEL);
+	if (!result)
+		return result;
+
+	copied = snprintf(result, len, CLIENT_MINORVERS_ENV_PREFIX "%u",
+				clp->cl_minorversion);
+	if (copied >= len) {
+		/* just return nothing if output was truncated */
+		kfree(result);
+		return NULL;
+	}
+
+	return result;
+}
+
+static char *
+nfsd4_cltrack_grace_start(time_t grace_start)
+{
+	int copied;
+	size_t len;
+	char *result;
+
+	/* prefix + max width of int64_t string + terminating NULL */
+	len = strlen(GRACE_START_ENV_PREFIX) + 22 + 1;
+
+	result = kmalloc(len, GFP_KERNEL);
+	if (!result)
+		return result;
+
+	copied = snprintf(result, len, GRACE_START_ENV_PREFIX "%ld",
+				grace_start);
+	if (copied >= len) {
+		/* just return nothing if output was truncated */
+		kfree(result);
+		return NULL;
+	}
+
+	return result;
+}
+
 static int
-nfsd4_umh_cltrack_upcall(char *cmd, char *arg, char *legacy)
+nfsd4_umh_cltrack_upcall(char *cmd, char *arg, char *env0, char *env1)
 {
-	char *envp[2];
+	char *envp[3];
 	char *argv[4];
 	int ret;
 

@@ -1140,10 +1192,12 @@ nfsd4_umh_cltrack_upcall(char *cmd, char *arg, char *legacy)
 
 	dprintk("%s: cmd: %s\n", __func__, cmd);
 	dprintk("%s: arg: %s\n", __func__, arg ? arg : "(null)");
-	dprintk("%s: legacy: %s\n", __func__, legacy ? legacy : "(null)");
+	dprintk("%s: env0: %s\n", __func__, env0 ? env0 : "(null)");
+	dprintk("%s: env1: %s\n", __func__, env1 ? env1 : "(null)");
 
-	envp[0] = legacy;
-	envp[1] = NULL;
+	envp[0] = env0;
+	envp[1] = env1;
+	envp[2] = NULL;
 
 	argv[0] = (char *)cltrack_prog;
 	argv[1] = cmd;

@@ -1187,28 +1241,40 @@ bin_to_hex_dup(const unsigned char *src, int srclen)
 }
 
 static int
-nfsd4_umh_cltrack_init(struct net __attribute__((unused)) *net)
+nfsd4_umh_cltrack_init(struct net *net)
 {
+	int ret;
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+	char *grace_start = nfsd4_cltrack_grace_start(nn->boot_time);
+
 	/* XXX: The usermode helper s not working in container yet. */
 	if (net != &init_net) {
 		WARN(1, KERN_ERR "NFSD: attempt to initialize umh client "
 			"tracking in a container!\n");
 		return -EINVAL;
 	}
-	return nfsd4_umh_cltrack_upcall("init", NULL, NULL);
+
+	ret = nfsd4_umh_cltrack_upcall("init", NULL, grace_start, NULL);
+	kfree(grace_start);
+	return ret;
 }
 
 static void
 nfsd4_umh_cltrack_create(struct nfs4_client *clp)
 {
-	char *hexid;
+	char *hexid, *minorvers, *grace_start;
+	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
 
 	hexid = bin_to_hex_dup(clp->cl_name.data, clp->cl_name.len);
 	if (!hexid) {
 		dprintk("%s: can't allocate memory for upcall!\n", __func__);
 		return;
 	}
-	nfsd4_umh_cltrack_upcall("create", hexid, NULL);
+	minorvers = nfsd4_cltrack_client_minorversion(clp);
+	grace_start = nfsd4_cltrack_grace_start(nn->boot_time);
+	nfsd4_umh_cltrack_upcall("create", hexid, minorvers, grace_start);
+	kfree(minorvers);
+	kfree(grace_start);
 	kfree(hexid);
 }
 

@@ -1222,7 +1288,7 @@ nfsd4_umh_cltrack_remove(struct nfs4_client *clp)
 		dprintk("%s: can't allocate memory for upcall!\n", __func__);
 		return;
 	}
-	nfsd4_umh_cltrack_upcall("remove", hexid, NULL);
+	nfsd4_umh_cltrack_upcall("remove", hexid, NULL, NULL);
 	kfree(hexid);
 }
 

@@ -1238,7 +1304,7 @@ nfsd4_umh_cltrack_check(struct nfs4_client *clp)
 		return -ENOMEM;
 	}
 	legacy = nfsd4_cltrack_legacy_recdir(&clp->cl_name);
-	ret = nfsd4_umh_cltrack_upcall("check", hexid, legacy);
+	ret = nfsd4_umh_cltrack_upcall("check", hexid, legacy, NULL);
 	kfree(legacy);
 	kfree(hexid);
 	return ret;

@@ -1252,7 +1318,7 @@ nfsd4_umh_cltrack_grace_done(struct nfsd_net *nn)
 
 	sprintf(timestr, "%ld", nn->boot_time);
 	legacy = nfsd4_cltrack_legacy_topdir();
-	nfsd4_umh_cltrack_upcall("gracedone", timestr, legacy);
+	nfsd4_umh_cltrack_upcall("gracedone", timestr, legacy, NULL);
 	kfree(legacy);
 }
 

index 6479c45a17c9..2506a0609b99 100644
@@ -6358,10 +6358,10 @@ nfs4_state_start_net(struct net *net)
 	ret = nfs4_state_create_net(net);
 	if (ret)
 		return ret;
-	nfsd4_client_tracking_init(net);
 	nn->boot_time = get_seconds();
-	locks_start_grace(net, &nn->nfsd4_manager);
 	nn->grace_ended = false;
+	locks_start_grace(net, &nn->nfsd4_manager);
+	nfsd4_client_tracking_init(net);
 	printk(KERN_INFO "NFSD: starting %ld-second grace period (net %p)\n",
 	       nn->nfsd4_grace, net);
 	queue_delayed_work(laundry_wq, &nn->laundromat_work, nn->nfsd4_grace * HZ);