smb3: if server does not support posix do not allow posix mount option

If user specifies "posix" on an SMB3.11 mount, then fail the mount
if server does not return the POSIX negotiate context indicating
support for posix.

Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 5df2c0698cda7a5ae093db0e3886b275bc0565cb..9d02563b2147e6e4aa52b3e6fe113b3ea5b3a90f 100644 (file)
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -3031,11 +3031,15 @@ cifs_get_tcon(struct cifs_ses *ses, struct smb_vol *volume_info)
        }
 
 #ifdef CONFIG_CIFS_SMB311
-       if ((volume_info->linux_ext) && (ses->server->posix_ext_supported)) {
-               if (ses->server->vals->protocol_id == SMB311_PROT_ID) {
+       if (volume_info->linux_ext) {
+               if (ses->server->posix_ext_supported) {
                        tcon->posix_extensions = true;
                        printk_once(KERN_WARNING
                                "SMB3.11 POSIX Extensions are experimental\n");
+               } else {
+                       cifs_dbg(VFS, "Server does not support mounting with posix SMB3.11 extensions.\n");
+                       rc = -EOPNOTSUPP;
+                       goto out_fail;
                }
        }
 #endif /* 311 */