[CIFS] Make sec=none force an anonymous mount

We had a customer report that attempting to make CIFS mount with a null
username (i.e. doing an anonymous mount) doesn't work. Looking through the
code, it looks like CIFS expects a NULL username from userspace in order
to trigger an anonymous mount. The mount.cifs code doesn't seem to ever
pass a null username to the kernel, however.

It looks also like the kernel can take a sec=none option, but it only seems
to look at it if the username is already NULL. This seems redundant and
effectively makes sec=none useless.

The following patch makes sec=none force an anonymous mount.

Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 17 insertions, 3 deletions

diff --git a/fs/cifs/README b/fs/cifs/README
index 93fe3594274f..80fcfb82eafd 100644
--- a/fs/cifs/README
+++ b/fs/cifs/README
@@ -472,7 +472,7 @@ including:
         -V      print mount.cifs version
         -?      display simple usage information
 
-With recent 2.6 kernel versions of modutils, the version of the cifs kernel
+With most 2.6 kernel versions of modutils, the version of the cifs kernel
 module can be displayed via modinfo.
 
 Misc /proc/fs/cifs Flags and Debug Info
@@ -521,8 +521,22 @@ SecurityFlags		Flags which control security negotiation and
                         must use plaintext passwords                    0x20020
                         (reserved for future packet encryption)         0x00040
 
-cifsFYI                 If set to one, additional debug information is
-                        logged to the system error log. (default 0)
+cifsFYI                 If set to non-zero value, additional debug information
+                        will be logged to the system error log.  This field
+                        contains three flags controlling different classes of
+                        debugging entries.  The maximum value it can be set
+                        to is 7 which enables all debugging points (default 0).
+                        Some debugging statements are not compiled into the
+                        cifs kernel unless CONFIG_CIFS_DEBUG2 is enabled in the
+                        kernel configuration. cifsFYI may be set to one or
+                        nore of the following flags (7 sets them all):
+
+                        log cifs informational messages                 0x01
+                        log return codes from cifs entry points         0x02
+                        log slow responses (ie which take longer than one second)
+                          CONFIG_CIFS_STATS2 must be enabled in .config 0x03
+                                
+                                
 traceSMB                If set to one, debug information is logged to the
                         system error log with the start of smb requests
                         and responses (default 0)