ubifs: Fix debug messages for an invalid filename in ubifs_dump_node

if a character is not printable, print '?' instead of that.
Signed-off-by: Hyunchul Lee <cheol.lee@lge.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

fs/ubifs/debug.c

@@ -32,6 +32,7 @@
 #include <linux/math64.h>
 #include <linux/uaccess.h>
 #include <linux/random.h>
+#include <linux/ctype.h>
 #include "ubifs.h"
 
 static DEFINE_SPINLOCK(dbg_lock);
@@ -464,7 +465,8 @@ void ubifs_dump_node(const struct ubifs_info *c, const void *node)
 			pr_err("(bad name length, not printing, bad or corrupted node)");
 		else {
 			for (i = 0; i < nlen && dent->name[i]; i++)
-				pr_cont("%c", dent->name[i]);
+				pr_cont("%c", isprint(dent->name[i]) ?
+					dent->name[i] : '?');
 		}
 		pr_cont("\n");