[PATCH] knfsd: allow sockets to be passed to nfsd via 'portlist'

Userspace should create and bind a socket (but not connectted) and write the
'fd' to portlist.  This will cause the nfs server to listen on that socket.

To close a socket, the name of the socket - as read from 'portlist' can be
written to 'portlist' with a preceding '-'.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/nfsd/nfsctl.c

@@ -24,9 +24,11 @@
 #include <linux/init.h>
 #include <linux/string.h>
 #include <linux/smp_lock.h>
+#include <linux/ctype.h>
 
 #include <linux/nfs.h>
 #include <linux/nfsd_idmap.h>
+#include <linux/lockd/bind.h>
 #include <linux/sunrpc/svc.h>
 #include <linux/sunrpc/svcsock.h>
 #include <linux/nfsd/nfsd.h>
@@ -426,16 +428,55 @@ static ssize_t write_versions(struct file *file, char *buf, size_t size)
 
 static ssize_t write_ports(struct file *file, char *buf, size_t size)
 {
-	/* for now, ignore what was written and just
-	 * return known ports
-	 * AF proto address port
+	if (size == 0) {
+		int len = 0;
+		lock_kernel();
+		if (nfsd_serv)
+			len = svc_sock_names(buf, nfsd_serv, NULL);
+		unlock_kernel();
+		return len;
+	}
+	/* Either a single 'fd' number is written, in which
+	 * case it must be for a socket of a supported family/protocol,
+	 * and we use it as an nfsd socket, or
+	 * A '-' followed by the 'name' of a socket in which case
+	 * we close the socket.
+	 */
+	if (isdigit(buf[0])) {
+		char *mesg = buf;
+		int fd;
+		int err;
+		err = get_int(&mesg, &fd);
+		if (err)
+			return -EINVAL;
+		if (fd < 0)
+			return -EINVAL;
+		err = nfsd_create_serv();
+		if (!err) {
+			int proto = 0;
+			err = svc_addsock(nfsd_serv, fd, buf, &proto);
+			/* Decrease the count, but don't shutdown the
+			 * the service
 			 */
+			if (err >= 0)
+				lockd_up(proto);
+			nfsd_serv->sv_nrthreads--;
+		}
+		return err;
+	}
+	if (buf[0] == '-') {
+		char *toclose = kstrdup(buf+1, GFP_KERNEL);
 		int len = 0;
+		if (!toclose)
+			return -ENOMEM;
 		lock_kernel();
 		if (nfsd_serv)
-		len = svc_sock_names(buf, nfsd_serv);
+			len = svc_sock_names(buf, nfsd_serv, toclose);
 		unlock_kernel();
+		kfree(toclose);
 		return len;
+	}
+	return -EINVAL;
 }
 
 #ifdef CONFIG_NFSD_V4

fs/nfsd/nfssvc.c

@@ -195,7 +195,7 @@ void nfsd_reset_versions(void)
 	}
 }
 
-static int nfsd_create_serv(void)
+int nfsd_create_serv(void)
 {
 	int err = 0;
 	lock_kernel();
@@ -210,8 +210,6 @@ static int nfsd_create_serv(void)
 			       nfsd_last_thread);
 	if (nfsd_serv == NULL)
 		err = -ENOMEM;
-	else
-		nfsd_serv->sv_nrthreads++;
 	unlock_kernel();
 	do_gettimeofday(&nfssvc_boot);		/* record boot time */
 	return err;

include/linux/nfsd/nfsd.h

@@ -143,6 +143,7 @@ int nfsd_set_posix_acl(struct svc_fh *, int, struct posix_acl *);
 enum vers_op {NFSD_SET, NFSD_CLEAR, NFSD_TEST, NFSD_AVAIL };
 int nfsd_vers(int vers, enum vers_op change);
 void nfsd_reset_versions(void);
+int nfsd_create_serv(void);
 
 
 /* 

include/linux/sunrpc/svcsock.h

@@ -61,6 +61,10 @@ int		svc_recv(struct svc_serv *, struct svc_rqst *, long);
 int		svc_send(struct svc_rqst *);
 void		svc_drop(struct svc_rqst *);
 void		svc_sock_update_bufs(struct svc_serv *serv);
-int		svc_sock_names(char *buf, struct svc_serv *serv);
+int		svc_sock_names(char *buf, struct svc_serv *serv, char *toclose);
+int		svc_addsock(struct svc_serv *serv,
+			    int fd,
+			    char *name_return,
+			    int *proto);
 
 #endif /* SUNRPC_SVCSOCK_H */

net/sunrpc/svcsock.c

@@ -31,6 +31,7 @@
 #include <linux/slab.h>
 #include <linux/netdevice.h>
 #include <linux/skbuff.h>
+#include <linux/file.h>
 #include <net/sock.h>
 #include <net/checksum.h>
 #include <net/ip.h>
@@ -451,9 +452,9 @@ static int one_sock_name(char *buf, struct svc_sock *svsk)
 }
 
 int
-svc_sock_names(char *buf, struct svc_serv *serv)
+svc_sock_names(char *buf, struct svc_serv *serv, char *toclose)
 {
-	struct svc_sock *svsk;
+	struct svc_sock *svsk, *closesk = NULL;
 	int len = 0;
 
 	if (!serv)
@@ -461,9 +462,14 @@ svc_sock_names(char *buf, struct svc_serv *serv)
 	spin_lock(&serv->sv_lock);
 	list_for_each_entry(svsk, &serv->sv_permsocks, sk_list) {
 		int onelen = one_sock_name(buf+len, svsk);
+		if (toclose && strcmp(toclose, buf+len) == 0)
+			closesk = svsk;
+		else
 			len += onelen;
 	}
 	spin_unlock(&serv->sv_lock);
+	if (closesk)
+		svc_delete_socket(closesk);
 	return len;
 }
 EXPORT_SYMBOL(svc_sock_names);
@@ -1407,6 +1413,38 @@ svc_setup_socket(struct svc_serv *serv, struct socket *sock,
 	return svsk;
 }
 
+int svc_addsock(struct svc_serv *serv,
+		int fd,
+		char *name_return,
+		int *proto)
+{
+	int err = 0;
+	struct socket *so = sockfd_lookup(fd, &err);
+	struct svc_sock *svsk = NULL;
+
+	if (!so)
+		return err;
+	if (so->sk->sk_family != AF_INET)
+		err =  -EAFNOSUPPORT;
+	else if (so->sk->sk_protocol != IPPROTO_TCP &&
+	    so->sk->sk_protocol != IPPROTO_UDP)
+		err =  -EPROTONOSUPPORT;
+	else if (so->state > SS_UNCONNECTED)
+		err = -EISCONN;
+	else {
+		svsk = svc_setup_socket(serv, so, &err, 1);
+		if (svsk)
+			err = 0;
+	}
+	if (err) {
+		sockfd_put(so);
+		return err;
+	}
+	if (proto) *proto = so->sk->sk_protocol;
+	return one_sock_name(name_return, svsk);
+}
+EXPORT_SYMBOL_GPL(svc_addsock);
+
 /*
  * Create socket for RPC service.
  */
@@ -1482,6 +1520,9 @@ svc_delete_socket(struct svc_sock *svsk)
 
 	if (!svsk->sk_inuse) {
 		spin_unlock_bh(&serv->sv_lock);
+		if (svsk->sk_sock->file)
+			sockfd_put(svsk->sk_sock);
+		else
 			sock_release(svsk->sk_sock);
 		kfree(svsk);
 	} else {