[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>

2 files changed, 51 insertions, 12 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;