diff --git a/lisp/dired.el b/lisp/dired.el
index 6c7445c..199e6ff 100644
--- a/lisp/dired.el
+++ b/lisp/dired.el
@@ -3359,23 +3359,16 @@ dired-mark-files-containing-regexp
      (and (not (looking-at-p dired-re-dot))
 	  (not (eolp))			; empty line
 	  (let ((fn (dired-get-filename nil t)))
-	    (when (and fn (file-readable-p fn)
-		       (not (file-directory-p fn)))
-	      (let ((prebuf (get-file-buffer fn)))
+	    (when (and fn (file-regular-p fn)
+                   (file-readable-p fn))
 		(message "Checking %s" fn)
 		;; For now we do it inside emacs
 		;; Grep might be better if there are a lot of files
-		(if prebuf
-		    (with-current-buffer prebuf
-		      (save-excursion
-			(goto-char (point-min))
-			(re-search-forward regexp nil t)))
-		  (with-temp-buffer
-		    (insert-file-contents fn)
-		    (goto-char (point-min))
-		    (re-search-forward regexp nil t))))
-		      )))
-     "matching file")))
+		(with-temp-buffer
+		  (insert-file-contents fn)
+		  (goto-char (point-min))
+		  (re-search-forward regexp nil t)))))
+	"matching file")))
 
 (defun dired-flag-files-regexp (regexp)
   "In Dired, flag all files containing the specified REGEXP for deletion.