ovl: fix format of setxattr debug

Format has a typo: it was meant to be "%.*s", not "%*s".  But at some point
callers grew nonprintable values as well, so use "%*pE" instead with a
maximized length.

Reported-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Fixes: 3a1e819b4e80 ("ovl: store file handle of lower inode on copy up")
Cc: <stable@vger.kernel.org> # v4.12

fs/overlayfs/overlayfs.h

@@ -152,8 +152,8 @@ static inline int ovl_do_setxattr(struct dentry *dentry, const char *name,
 				  const void *value, size_t size, int flags)
 {
 	int err = vfs_setxattr(dentry, name, value, size, flags);
-	pr_debug("setxattr(%pd2, \"%s\", \"%*s\", 0x%x) = %i\n",
-		 dentry, name, (int) size, (char *) value, flags, err);
+	pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, 0x%x) = %i\n",
+		 dentry, name, min((int)size, 48), value, size, flags, err);
 	return err;
 }