Better error message for mysql_upgrade if upgrade file can't be updated.

client/mysql_upgrade.c

@@ -673,7 +673,7 @@ static int get_upgrade_info_file_name(char* name)
 
 */
 
-static int upgrade_already_done(void)
+static int upgrade_already_done(myf flags)
 {
   FILE *in;
   char upgrade_info_file[FN_REFLEN]= {0};
@@ -681,17 +681,23 @@ static int upgrade_already_done(void)
   if (get_upgrade_info_file_name(upgrade_info_file))
     return 0; /* Could not get filename => not sure */
 
-  if (!(in= my_fopen(upgrade_info_file, O_RDONLY, MYF(0))))
+  if (!(in= my_fopen(upgrade_info_file, O_RDONLY, flags)))
     return 0; /* Could not open file => not sure */
 
   bzero(upgrade_from_version, sizeof(upgrade_from_version));
   if (!fgets(upgrade_from_version, sizeof(upgrade_from_version), in))
   {
-    /* Ignore, will be detected by strncmp() below */
+    /* Preserve errno for caller */
+    int save_errno= errno;
+    (void) my_fclose(in, flags);
+    errno= save_errno;
+    return 0;
   }
 
-  my_fclose(in, MYF(0));
+  if (my_fclose(in, flags))
+    return 0;
 
+  errno= 0;
   return (strncmp(upgrade_from_version, MYSQL_SERVER_VERSION,
                   sizeof(MYSQL_SERVER_VERSION)-1)==0);
 }
@@ -720,23 +726,24 @@ static void create_mysql_upgrade_info_file(void)
   {
     fprintf(stderr,
             "Could not create the upgrade info file '%s' in "
-            "the MySQL Servers datadir, errno: %d\n",
+            "the MariaDB Servers datadir, errno: %d\n",
             upgrade_info_file, errno);
     return;
   }
 
   /* Write new version to file */
-  fputs(MYSQL_SERVER_VERSION, out);
-  my_fclose(out, MYF(0));
+  my_fwrite(out, (uchar*) MYSQL_SERVER_VERSION,
+            sizeof(MYSQL_SERVER_VERSION), MY_WME);
+  my_fclose(out, MYF(MY_WME));
 
   /*
     Check if the upgrad_info_file was properly created/updated
     It's not a fatal error -> just print a message if it fails
   */
-  if (!upgrade_already_done())
+  if (!upgrade_already_done(MY_WME))
     fprintf(stderr,
-            "Could not write to the upgrade info file '%s' in "
-            "the MySQL Servers datadir, errno: %d\n",
+            "Upgrade file '%s' was not properly created. "
+            "Got error errno while checking file content: %d\n",
             upgrade_info_file, errno);
   return;
 }
@@ -1191,7 +1198,7 @@ int main(int argc, char **argv)
     Read the mysql_upgrade_info file to check if mysql_upgrade
     already has been run for this installation of MySQL
   */
-  if (!opt_force && upgrade_already_done())
+  if (!opt_force && upgrade_already_done(0))
   {
     printf("This installation of MySQL is already upgraded to %s, "
            "use --force if you still need to run mysql_upgrade\n",