New helper - current_umask()

current->fs->umask is what most of fs_struct users are doing.
Put that into a helper function.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/fat/inode.c

@@ -930,7 +930,7 @@ static int parse_options(char *options, int is_vfat, int silent, int *debug,
 
 	opts->fs_uid = current_uid();
 	opts->fs_gid = current_gid();
-	opts->fs_fmask = opts->fs_dmask = current->fs->umask;
+	opts->fs_fmask = current_umask();
 	opts->allow_utime = -1;
 	opts->codepage = fat_default_codepage;
 	opts->iocharset = fat_default_iocharset;