cifs: handle "sloppy" option appropriately

cifs.ko has historically been tolerant of options that it does not
recognize. This is not normal behavior for a filesystem however.
Usually, it should only do this if you mount with '-s', and autofs
generally passes -s to the mount command to allow this behavior.

This patch makes cifs handle the option "sloppy" appropriately. If it's
present in the options string, then the client will tolerate options
that it doesn't recognize. If it's not present then the client will
error out in the presence of options that it does not recognize and
throw an error message explaining why.

There is also a companion patch being proposed for mount.cifs to make it
append "sloppy" to the mount options when passed the '-s' flag. This also
should (obviously) be applied on top of Sachin's conversion to the
standard option parser.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Acked-By: Sachin Prabhu <sprabhu@redhat.com>

fs/cifs/connect.c

@@ -88,7 +88,7 @@ enum {
 	Opt_sign, Opt_seal, Opt_direct,
 	Opt_strictcache, Opt_noac,
 	Opt_fsc, Opt_mfsymlinks,
-	Opt_multiuser,
+	Opt_multiuser, Opt_sloppy,
 
 	/* Mount options which take numeric value */
 	Opt_backupuid, Opt_backupgid, Opt_uid,
@@ -167,6 +167,7 @@ static const match_table_t cifs_mount_option_tokens = {
 	{ Opt_fsc, "fsc" },
 	{ Opt_mfsymlinks, "mfsymlinks" },
 	{ Opt_multiuser, "multiuser" },
+	{ Opt_sloppy, "sloppy" },
 
 	{ Opt_backupuid, "backupuid=%s" },
 	{ Opt_backupgid, "backupgid=%s" },
@@ -1186,6 +1187,8 @@ cifs_parse_mount_options(const char *mountdata, const char *devname,
 	short int override_gid = -1;
 	bool uid_specified = false;
 	bool gid_specified = false;
+	bool sloppy = false;
+	char *invalid = NULL;
 	char *nodename = utsname()->nodename;
 	char *string = NULL;
 	char *tmp_end, *value;
@@ -1423,6 +1426,9 @@ cifs_parse_mount_options(const char *mountdata, const char *devname,
 		case Opt_multiuser:
 			vol->multiuser = true;
 			break;
+		case Opt_sloppy:
+			sloppy = true;
+			break;
 
 		/* Numeric Values */
 		case Opt_backupuid:
@@ -1870,8 +1876,12 @@ cifs_parse_mount_options(const char *mountdata, const char *devname,
 				goto cifs_parse_mount_err;
 			break;
 		default:
-			printk(KERN_WARNING "CIFS: Unknown mount option %s\n",
-						data);
+			/*
+			 * An option we don't recognize. Save it off for later
+			 * if we haven't already found one
+			 */
+			if (!invalid)
+				invalid = data;
 			break;
 		}
 		/* Free up any allocated string */
@@ -1879,6 +1889,11 @@ cifs_parse_mount_options(const char *mountdata, const char *devname,
 		string = NULL;
 	}
 
+	if (!sloppy && invalid) {
+		printk(KERN_ERR "CIFS: Unknown mount option \"%s\"\n", invalid);
+		goto cifs_parse_mount_err;
+	}
+
 #ifndef CONFIG_KEYS
 	/* Muliuser mounts require CONFIG_KEYS support */
 	if (vol->multiuser) {