smb3: minor debugging clarifications in rfc1001 len processing

I ran into some cases where server was returning the wrong length
on frames but I couldn't easily match them to the command in the
network trace (or server logs) since I need the command and/or
multiplex id to find the offending SMB2/SMB3 command.  Add these
two fields to the log message. In the case of padding too much
it may not be a problem in all cases but might have correlated
to a network disconnect case in some problems we have been
looking at. In the case of frame too short is even more important.

Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>

diff --git a/fs/cifs/smb2misc.c b/fs/cifs/smb2misc.c
index db0453660ff6c97d9d7ab66991d9b192fadcaed7..6a9c47541c53d0983a068703106ddacdbc834e04 100644 (file)
--- a/fs/cifs/smb2misc.c
+++ b/fs/cifs/smb2misc.c
@@ -248,16 +248,20 @@ smb2_check_message(char *buf, unsigned int len, struct TCP_Server_Info *srvr)
                 * MacOS server pads after SMB2.1 write response with 3 bytes
                 * of junk. Other servers match RFC1001 len to actual
                 * SMB2/SMB3 frame length (header + smb2 response specific data)
-                * Some windows servers do too when compounding is used.
-                * Log the server error (once), but allow it and continue
+                * Some windows servers also pad up to 8 bytes when compounding.
+                * If pad is longer than eight bytes, log the server behavior
+                * (once), since may indicate a problem but allow it and continue
                 * since the frame is parseable.
                 */
                if (clc_len < len) {
-                       printk_once(KERN_WARNING
-                               "SMB2 server sent bad RFC1001 len %d not %d\n",
-                               len, clc_len);
+                       pr_warn_once(
+                            "srv rsp padded more than expected. Length %d not %d for cmd:%d mid:%llu\n",
+                            len, clc_len, command, mid);
                        return 0;
                }
+               pr_warn_once(
+                       "srv rsp too short, len %d not %d. cmd:%d mid:%llu\n",
+                       len, clc_len, command, mid);
 
                return 1;
        }