Fix NULL as mount(2) syscall data parameter

Passing NULL for the mount data should not result in EINVAL.  It
should be treated as if an empty string were passed and succeed.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ned Bass <bass6@llnl.gov>
Closes #3771

diff --git a/module/zfs/zpl_super.c b/module/zfs/zpl_super.c
index 3edacba462eeb88d687e893c85abca8308e1b619..80cc15725c8f08c0eaaafbb5b8583a3e02f60d63 100644 (file)
--- a/module/zfs/zpl_super.c
+++ b/module/zfs/zpl_super.c
@@ -227,8 +227,7 @@ static const match_table_t zpl_tokens = {
 };
 
 static int
-zpl_parse_option(char *option, int token, substring_t *args,
-    zfs_mntopts_t *zmo, boolean_t isremount)
+zpl_parse_option(char *option, int token, substring_t *args, zfs_mntopts_t *zmo)
 {
        switch (token) {
        case TOKEN_RO:
@@ -318,32 +317,34 @@ zpl_parse_options(char *osname, char *mntopts, zfs_mntopts_t *zmo,
     boolean_t isremount)
 {
        zfs_mntopts_t *tmp_zmo;
-       substring_t args[MAX_OPT_ARGS];
-       char *tmp_mntopts, *p;
-       int error, token;
-
-       if (mntopts == NULL)
-               return (-EINVAL);
+       int error;
 
        tmp_zmo = zfs_mntopts_alloc();
        tmp_zmo->z_osname = strdup(osname);
-       tmp_mntopts = strdup(mntopts);
-
-       while ((p = strsep(&tmp_mntopts, ",")) != NULL) {
-               if (!*p)
-                       continue;
-
-               args[0].to = args[0].from = NULL;
-               token = match_token(p, zpl_tokens, args);
-               error = zpl_parse_option(p, token, args, tmp_zmo, isremount);
-               if (error) {
-                       zfs_mntopts_free(tmp_zmo);
-                       strfree(tmp_mntopts);
-                       return (error);
+
+       if (mntopts) {
+               substring_t args[MAX_OPT_ARGS];
+               char *tmp_mntopts, *p;
+               int token;
+
+               tmp_mntopts = strdup(mntopts);
+
+               while ((p = strsep(&tmp_mntopts, ",")) != NULL) {
+                       if (!*p)
+                               continue;
+
+                       args[0].to = args[0].from = NULL;
+                       token = match_token(p, zpl_tokens, args);
+                       error = zpl_parse_option(p, token, args, tmp_zmo);
+                       if (error) {
+                               zfs_mntopts_free(tmp_zmo);
+                               strfree(tmp_mntopts);
+                               return (error);
+                       }
                }
-       }
 
-       strfree(tmp_mntopts);
+               strfree(tmp_mntopts);
+       }
 
        if (isremount == B_TRUE) {
                if (zmo->z_osname)