Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932172Ab0KOXD7 (ORCPT ); Mon, 15 Nov 2010 18:03:59 -0500 Received: from mail-pw0-f46.google.com ([209.85.160.46]:50797 "EHLO mail-pw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758820Ab0KOXD4 convert rfc822-to-8bit (ORCPT ); Mon, 15 Nov 2010 18:03:56 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=c5at3dyHl7IkcoUuXC0Gp7INNk3gMtWr5DZU6CDOpdyk41qWXf0OvcZnaZVMVUTH7h Y9c4cOop5HCX5BGOQvdxzC68W9XyPUzgUeetsdqqw4usf1otJbZ2bGeZWtXYhCz1accB 544JfL0dk/qKVWHX5OF+PAwYubKAZAOTNESVo= MIME-Version: 1.0 In-Reply-To: <1289861518.14282.41.camel@localhost.localdomain> References: <1289859078.14282.28.camel@localhost.localdomain> <1289861518.14282.41.camel@localhost.localdomain> Date: Tue, 16 Nov 2010 02:03:56 +0300 Message-ID: Subject: Re: A possible flaw in the fsnotify design. From: Alexey Zaytsev To: Eric Paris Cc: Tvrtko Ursulin , linux-fsdevel@vger.kernel.org, "stefan@buettcher.org" , linux-kernel@vger.kernel.org, Al Viro Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1713 Lines: 39 On Tue, Nov 16, 2010 at 01:51, Eric Paris wrote: > On Tue, 2010-11-16 at 01:44 +0300, Alexey Zaytsev wrote: >> On Tue, Nov 16, 2010 at 01:11, Eric Paris wrote: >> > On Tue, 2010-11-16 at 01:05 +0300, Alexey Zaytsev wrote: >> >> Just some thoughts. >> >> >> >> Consider the situation: Files A and B both point to the same inode. >> >> File A is being watched, but the user won't get notifications if B is >> >> modified. >> > >> > That's not true.  Users watch inodes, not files (this is true for both >> > inotify and fanotify).  Give it a try, it works. >> > >> >> debian-i386:~/tmp# touch a >> debian-i386:~/tmp# ../fanotify a & >> debian-i386:~/tmp# link a b >> debian-i386:~/tmp# ls -li >> total 0 >> 3433 -rw-r--r-- 2 root root 0 Nov 15 22:37 a >> 3433 -rw-r--r-- 2 root root 0 Nov 15 22:37 b >> debian-i386:~/tmp# echo 123 > b >> /root/tmp/b: pid=2143 mask = 20 open >> /root/tmp/b: pid=2143 mask = a modify 0 - 4 close(writable)  0 - 4 >> >> Am I doing something wrong? Same thing happens if I watch the mount point. > > Maybe I don't understand the problem, you watched the inode behind A. > You made changes accessing this inode via B, you got notification about > those changes.  Isn't that what you wanted? I'd expect to get two notifications in this case. Might not be a problem when you are watching individual files, but there is no clear way to get all the modified files, if you are watching a mount point. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/