[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>

5 files changed, 102 insertions, 17 deletions

diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index d4041a05bc19..80e97a5ffc3f 100644
--- a/fs/nfsd/nfsctl.c
+++ b/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.
          */
-        int len = 0;
-        lock_kernel();
-        if (nfsd_serv)
-                len = svc_sock_names(buf, nfsd_serv);
-        unlock_kernel();
-        return len;
+        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, toclose);
+                unlock_kernel();
+                kfree(toclose);
+                return len;
+        }
+        return -EINVAL;
 }
 
 #ifdef CONFIG_NFSD_V4
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index 5d473d8f0630..784f94fbebf3 100644
--- a/fs/nfsd/nfssvc.c
+++ b/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;
diff --git a/include/linux/nfsd/nfsd.h b/include/linux/nfsd/nfsd.h
index 46f1dc5b96dd..e1dbc86c270b 100644
--- a/include/linux/nfsd/nfsd.h
+++ b/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);
 
 
 /* 
diff --git a/include/linux/sunrpc/svcsock.h b/include/linux/sunrpc/svcsock.h
index 3caf92d72a81..b8a9652b8755 100644
--- a/include/linux/sunrpc/svcsock.h
+++ b/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 */
diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index 3ee4b78742b1..c6be67a86ae7 100644
--- a/net/sunrpc/svcsock.c
+++ b/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);
-                len += onelen;
+                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.
  */
@@ -1482,7 +1520,10 @@ svc_delete_socket(struct svc_sock *svsk)
 
         if (!svsk->sk_inuse) {
                 spin_unlock_bh(&serv->sv_lock);
-                sock_release(svsk->sk_sock);
+                if (svsk->sk_sock->file)
+                        sockfd_put(svsk->sk_sock);
+                else
+                        sock_release(svsk->sk_sock);
                 kfree(svsk);
         } else {
                 spin_unlock_bh(&serv->sv_lock);