NFSv4: Allow user to set the port used by the NFSv4 callback channel

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Documentation/kernel-parameters.txt

@@ -910,6 +910,10 @@ running once the system is up.
 	nfsroot=	[NFS] nfs root filesystem for disk-less boxes.
 			See Documentation/nfsroot.txt.
 
+	nfs.callback_tcpport=
+			[NFS] set the TCP port on which the NFSv4 callback
+			channel should listen.
+
 	nmi_watchdog=	[KNL,BUGS=IA-32] Debugging features for SMP kernels
 
 	no387		[BUGS=IA-32] Tells the kernel to use the 387 maths

fs/nfs/Makefile

@@ -13,4 +13,5 @@ nfs-$(CONFIG_NFS_V4)	+= nfs4proc.o nfs4xdr.o nfs4state.o nfs4renewd.o \
 			   delegation.o idmap.o \
 			   callback.o callback_xdr.o callback_proc.o
 nfs-$(CONFIG_NFS_DIRECTIO) += direct.o
+nfs-$(CONFIG_SYSCTL) += sysctl.o
 nfs-objs		:= $(nfs-y)

fs/nfs/callback.c

@@ -34,6 +34,7 @@ static struct nfs_callback_data nfs_callback_info;
 static DECLARE_MUTEX(nfs_callback_sema);
 static struct svc_program nfs4_callback_program;
 
+unsigned int nfs_callback_set_tcpport;
 unsigned short nfs_callback_tcpport;
 
 /*
@@ -98,7 +99,7 @@ int nfs_callback_up(void)
 	if (!serv)
 		goto out_err;
 	/* FIXME: We don't want to register this socket with the portmapper */
-	ret = svc_makesock(serv, IPPROTO_TCP, 0);
+	ret = svc_makesock(serv, IPPROTO_TCP, nfs_callback_set_tcpport);
 	if (ret < 0)
 		goto out_destroy;
 	if (!list_empty(&serv->sv_permsocks)) {

fs/nfs/callback.h

@@ -65,6 +65,7 @@ extern unsigned nfs4_callback_recall(struct cb_recallargs *args, void *dummy);
 extern int nfs_callback_up(void);
 extern int nfs_callback_down(void);
 
+extern unsigned int nfs_callback_set_tcpport;
 extern unsigned short nfs_callback_tcpport;
 
 #endif /* __LINUX_FS_NFS_CALLBACK_H */

fs/nfs/inode.c

@@ -40,6 +40,7 @@
 #include <asm/uaccess.h>
 
 #include "nfs4_fs.h"
+#include "callback.h"
 #include "delegation.h"
 
 #define NFSDBG_FACILITY		NFSDBG_VFS
@@ -2036,6 +2037,21 @@ static struct file_system_type nfs4_fs_type = {
 	.fs_flags	= FS_ODD_RENAME|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 };
 
+static const int nfs_set_port_min = 0;
+static const int nfs_set_port_max = 65535;
+static int param_set_port(const char *val, struct kernel_param *kp)
+{
+	char *endp;
+	int num = simple_strtol(val, &endp, 0);
+	if (endp == val || *endp || num < nfs_set_port_min || num > nfs_set_port_max)
+		return -EINVAL;
+	*((int *)kp->arg) = num;
+	return 0;
+}
+
+module_param_call(callback_tcpport, param_set_port, param_get_int,
+		 &nfs_callback_set_tcpport, 0644);
+
 #define nfs4_init_once(nfsi) \
 	do { \
 		INIT_LIST_HEAD(&(nfsi)->open_states); \
@@ -2043,8 +2059,25 @@ static struct file_system_type nfs4_fs_type = {
 		nfsi->delegation_state = 0; \
 		init_rwsem(&nfsi->rwsem); \
 	} while(0)
-#define register_nfs4fs() register_filesystem(&nfs4_fs_type)
-#define unregister_nfs4fs() unregister_filesystem(&nfs4_fs_type)
+
+static inline int register_nfs4fs(void)
+{
+	int ret;
+
+	ret = nfs_register_sysctl();
+	if (ret != 0)
+		return ret;
+	ret = register_filesystem(&nfs4_fs_type);
+	if (ret != 0)
+		nfs_unregister_sysctl();
+	return ret;
+}
+
+static inline void unregister_nfs4fs(void)
+{
+	unregister_filesystem(&nfs4_fs_type);
+	nfs_unregister_sysctl();
+}
 #else
 #define nfs4_init_once(nfsi) \
 	do { } while (0)

fs/nfs/sysctl.c

@@ -0,0 +1,74 @@
+/*
+ * linux/fs/nfs/sysctl.c
+ *
+ * Sysctl interface to NFS parameters
+ */
+#include <linux/config.h>
+#include <linux/types.h>
+#include <linux/linkage.h>
+#include <linux/ctype.h>
+#include <linux/fs.h>
+#include <linux/sysctl.h>
+#include <linux/module.h>
+#include <linux/nfs4.h>
+
+#include "callback.h"
+
+static const int nfs_set_port_min = 0;
+static const int nfs_set_port_max = 65535;
+static struct ctl_table_header *nfs_callback_sysctl_table;
+/*
+ * Something that isn't CTL_ANY, CTL_NONE or a value that may clash.
+ * Use the same values as fs/lockd/svc.c
+ */
+#define CTL_UNNUMBERED -2
+
+static ctl_table nfs_cb_sysctls[] = {
+#ifdef CONFIG_NFS_V4
+	{
+		.ctl_name = CTL_UNNUMBERED,
+		.procname = "nfs_callback_tcpport",
+		.data = &nfs_callback_set_tcpport,
+		.maxlen = sizeof(int),
+		.mode = 0644,
+		.proc_handler = &proc_dointvec_minmax,
+		.extra1 = (int *)&nfs_set_port_min,
+		.extra2 = (int *)&nfs_set_port_max,
+	},
+#endif
+	{ .ctl_name = 0 }
+};
+
+static ctl_table nfs_cb_sysctl_dir[] = {
+	{
+		.ctl_name = CTL_UNNUMBERED,
+		.procname = "nfs",
+		.mode = 0555,
+		.child = nfs_cb_sysctls,
+	},
+	{ .ctl_name = 0 }
+};
+
+static ctl_table nfs_cb_sysctl_root[] = {
+	{
+		.ctl_name = CTL_FS,
+		.procname = "fs",
+		.mode = 0555,
+		.child = nfs_cb_sysctl_dir,
+	},
+	{ .ctl_name = 0 }
+};
+
+int nfs_register_sysctl(void)
+{
+	nfs_callback_sysctl_table = register_sysctl_table(nfs_cb_sysctl_root, 0);
+	if (nfs_callback_sysctl_table == NULL)
+		return -ENOMEM;
+	return 0;
+}
+
+void nfs_unregister_sysctl(void)
+{
+	unregister_sysctl_table(nfs_callback_sysctl_table);
+	nfs_callback_sysctl_table = NULL;
+}

include/linux/nfs_fs.h

@@ -391,6 +391,17 @@ extern int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fh, struct nfs_
  */
 extern struct inode_operations nfs_symlink_inode_operations;
 
+/*
+ * linux/fs/nfs/sysctl.c
+ */
+#ifdef CONFIG_SYSCTL
+extern int nfs_register_sysctl(void);
+extern void nfs_unregister_sysctl(void);
+#else
+#define nfs_register_sysctl() do { } while(0)
+#define nfs_unregister_sysctl() do { } while(0)
+#endif
+
 /*
  * linux/fs/nfs/unlink.c
  */