2 files changed, 39 insertions, 6 deletions

diff --git a/fs/cifs/CHANGES b/fs/cifs/CHANGES
index c65c9da863f3..6d3e736612ba 100644
--- a/fs/cifs/CHANGES
+++ b/fs/cifs/CHANGES
@@ -14,7 +14,10 @@ bigendian architectures. Fix possible memory corruption when
 EAGAIN returned on kern_recvmsg. Return better error if server
 requires packet signing but client has disabled it. When mounted
 with cifsacl mount option - mode bits are approximated based
-on the contents of the files ACL.
+on the contents of the ACL of the file or directory. When cifs
+mount helper is missing convert make sure that UNC name 
+has backslash (not forward slash) between ip address of server
+and the share name.
 
 Version 1.50
 ------------
diff --git a/fs/cifs/netmisc.c b/fs/cifs/netmisc.c
index 4d35c034755a..e1704da43836 100644
--- a/fs/cifs/netmisc.c
+++ b/fs/cifs/netmisc.c
@@ -132,6 +132,34 @@ static const struct smb_to_posix_error mapping_table_ERRHRD[] = {
         {0, 0}
 };
 
+
+/* if the mount helper is missing we need to reverse the 1st slash
+   from '/' to backslash in order to format the UNC properly for
+   ip address parsing and for tree connect (unless the user
+   remembered to put the UNC name in properly). Fortunately we do
+   not have to call this twice (we check for IPv4 addresses
+   first, so it is already converted by the time we
+   try IPv6 addresses */
+static int canonicalize_unc(char *cp)
+{
+        int i;
+
+        for (i = 0; i <= 46 /* INET6_ADDRSTRLEN */ ; i++) {
+                if (cp[i] == 0)
+                        break;
+                if (cp[i] == '\\')
+                        break;
+                if (cp[i] == '/') {
+#ifdef CONFIG_CIFS_DEBUG2
+                        cFYI(1, ("change slash to backslash in malformed UNC"));
+#endif
+                        cp[i] = '\\';
+                        return 1;
+                }
+        }
+        return 0;
+}
+
 /* Convert string containing dotted ip address to binary form */
 /* returns 0 if invalid address */
 
@@ -141,11 +169,13 @@ cifs_inet_pton(int address_family, char *cp, void *dst)
         int ret = 0;
 
         /* calculate length by finding first slash or NULL */
-        /* BB Should we convert '/' slash to '\' here since it seems already
-         * done before this */
-        if ( address_family == AF_INET ) {
-                ret = in4_pton(cp, -1 /* len */, dst , '\\', NULL);
-        } else if ( address_family == AF_INET6 ) {
+        if (address_family == AF_INET) {
+                ret = in4_pton(cp, -1 /* len */, dst, '\\', NULL);
+                if (ret == 0) {
+                        if (canonicalize_unc(cp))
+                                ret = in4_pton(cp, -1, dst, '\\', NULL);
+                }
+        } else if (address_family == AF_INET6) {
                 ret = in6_pton(cp, -1 /* len */, dst , '\\', NULL);
         }
 #ifdef CONFIG_CIFS_DEBUG2