PATCH] cifs: fix broken mounts when a SSH tunnel is used (try #4)

One more try..

It seems there is a regression that got introduced while Jeff fixed
all the mount/umount races. While attempting to find whether a tcp
session is already existing, we were not checking whether the "port"
used are the same. When a second mount is attempted with a different
"port=" option, it is being ignored. Because of this the cifs mounts
that uses a SSH tunnel appears to be broken.

Steps to reproduce:

1. create 2 shares
# SSH Tunnel a SMB session
2. ssh -f -L 6111:127.0.0.1:445 root@localhost "sleep 86400"
3. ssh -f -L 6222:127.0.0.1:445 root@localhost "sleep 86400"
4. tcpdump -i lo 6111 &
5. mkdir -p /mnt/mnt1
6. mkdir -p /mnt/mnt2
7. mount.cifs //localhost/a /mnt/mnt1 -o username=guest,ip=127.0.0.1,port=6111
#(shows tcpdump activity on port 6111)
8. mount.cifs //localhost/b /mnt/mnt2 -o username=guest,ip=127.0.0.1,port=6222
#(shows tcpdump activity only on port 6111 and not on 6222

Fix by adding a check to compare the port _only_ if the user tries to
override the tcp port with "port=" option, before deciding that an
existing tcp session is found. Also, clean up a bit by replacing
if-else if by a switch statment while at it as suggested by Jeff.

Reviewed-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Shirish Pargaonkar <shirishp@us.ibm.com>
Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 33 insertions, 12 deletions

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 1f3345d7fa79..4e47a9b800ce 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -1377,7 +1377,7 @@ cifs_parse_mount_options(char *options, const char *devname,
 }
 
 static struct TCP_Server_Info *
-cifs_find_tcp_session(struct sockaddr_storage *addr)
+cifs_find_tcp_session(struct sockaddr_storage *addr, unsigned short int port)
 {
         struct list_head *tmp;
         struct TCP_Server_Info *server;
@@ -1397,16 +1397,37 @@ cifs_find_tcp_session(struct sockaddr_storage *addr)
                 if (server->tcpStatus == CifsNew)
                         continue;
 
-                if (addr->ss_family == AF_INET &&
-                    (addr4->sin_addr.s_addr !=
-                     server->addr.sockAddr.sin_addr.s_addr))
-                        continue;
-                else if (addr->ss_family == AF_INET6 &&
-                         (!ipv6_addr_equal(&server->addr.sockAddr6.sin6_addr,
-                                           &addr6->sin6_addr) ||
-                          server->addr.sockAddr6.sin6_scope_id !=
-                                           addr6->sin6_scope_id))
-                        continue;
+                switch (addr->ss_family) {
+                case AF_INET:
+                        if (addr4->sin_addr.s_addr ==
+                            server->addr.sockAddr.sin_addr.s_addr) {
+                                addr4->sin_port = htons(port);
+                                /* user overrode default port? */
+                                if (addr4->sin_port) {
+                                        if (addr4->sin_port !=
+                                            server->addr.sockAddr.sin_port)
+                                                continue;
+                                }
+                                break;
+                        } else
+                                continue;
+
+                case AF_INET6:
+                        if (ipv6_addr_equal(&addr6->sin6_addr,
+                            &server->addr.sockAddr6.sin6_addr) &&
+                            (addr6->sin6_scope_id == 
+                            server->addr.sockAddr6.sin6_scope_id)) {
+                                addr6->sin6_port = htons(port);
+                                /* user overrode default port? */
+                                if (addr6->sin6_port) {
+                                       if (addr6->sin6_port !=
+                                           server->addr.sockAddr6.sin6_port)
+                                               continue;
+                                }
+                                break;
+                        } else 
+                                continue;
+                }
 
                 ++server->srv_count;
                 write_unlock(&cifs_tcp_ses_lock);
@@ -1475,7 +1496,7 @@ cifs_get_tcp_session(struct smb_vol *volume_info)
         }
 
         /* see if we already have a matching tcp_ses */
-        tcp_ses = cifs_find_tcp_session(&addr);
+        tcp_ses = cifs_find_tcp_session(&addr, volume_info->port);
         if (tcp_ses)
                 return tcp_ses;