dnotify readv/writev fix for 2.4.21

dnotify readv/writev fix for 2.4.21

[Andy Isaacson]

Marcelo,

This patch didn't make it into 2.4.21.  Zou Pengcheng's original patch
was whitespace-damaged, so here's a fresh copy against 2.4.21.

Issue DN_MODIFY on writev, and DN_ACCESS on readv, rather than vice versa.

I can provide a testcase if anyone wants one.

----- Forwarded message from Zou Pengcheng <pczou@redflag-linux.com> -----

From: Zou Pengcheng <pczou@redflag-linux.com>
To: Marcelo Tosatti <marcelo@conectiva.com.br>
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH] dnotify fix for readv/writev (Linux 2.4.20)
Date:	Mon, 2 Dec 2002 09:22:43 +0800
Message-Id: <200212020922.43820.pczou@redflag-linux.com>

hi, Marcelo,

this is a patch to fix the dnotify bug of readv/writev. 

Orignally DN_MODIFY is issued on readv while DN_ACCESS is issued on writev, 
which is obviously wrong. This patch fixes such problem.

cheers,
  -- Pengcheng Zou

diff -uNr fs/read_write.c.orig fs/read_write.c
...

----- End forwarded message -----


--- linux-2.4.21/fs/read_write.c	Fri Jun 13 09:51:37 2003
+++ linux-2.4.21-dnotify-fix/fs/read_write.c	Thu Jun 19 11:55:30 2003
@@ -322,7 +322,7 @@
 	/* VERIFY_WRITE actually means a read, as we write to user space */
 	if ((ret + (type == VERIFY_WRITE)) > 0)
 		dnotify_parent(file->f_dentry,
-			(type == VERIFY_WRITE) ? DN_MODIFY : DN_ACCESS);
+			(type == VERIFY_WRITE) ? DN_ACCESS : DN_MODIFY);
 	return ret;
 }
 

-andy