From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934680AbXGSWE2 (ORCPT ); Thu, 19 Jul 2007 18:04:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1763320AbXGSWEU (ORCPT ); Thu, 19 Jul 2007 18:04:20 -0400 Received: from smtp2.linux-foundation.org ([207.189.120.14]:57426 "EHLO smtp2.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1763220AbXGSWET (ORCPT ); Thu, 19 Jul 2007 18:04:19 -0400 Date: Thu, 19 Jul 2007 15:03:55 -0700 From: Andrew Morton To: Thomas Ogrisegg Cc: linux-kernel@vger.kernel.org, rml@novell.com, John McCutchan , "Eric W. Biederman" , robin.ksj@gmail.com Subject: Re: [PATCH] procfs fixes for inotify/dnotify Message-Id: <20070719150355.2971e8e4.akpm@linux-foundation.org> In-Reply-To: <20060221211623.GA26413@rescue.iwoars.net> References: <20060221211623.GA26413@rescue.iwoars.net> X-Mailer: Sylpheed version 2.2.7 (GTK+ 2.8.6; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 21 Feb 2006 22:16:23 +0100 Thomas Ogrisegg wrote: > Problem description: > When a new process is created, the creation of the respective PID > subdirectory of /proc is deferred until the /proc-directory is beeing > read (by e.g. ps(1)). This causes file notification frameworks like > dnotify and inotify to not work correctly with /proc. > > This patch fixes the problem. > > Signed-off-by: Thomas Ogrisegg Robin has raised this report: http://bugzilla.kernel.org/show_bug.cgi?id=8782 pointing at your 15-month-old patch, which seemed to have got lost. The patch rather doesn't work any more. If you have time to update it then please do so, and copy John and Eric on the patch? Thanks. A few things I noticed: > > diff -uNr -X linux-2.6.15/Documentation/dontdiff linux-2.6.15/kernel/fork.c linux-2.6.15.4/kernel/fork.c > --- linux-2.6.15/kernel/fork.c 2006-01-03 04:21:10.000000000 +0100 > +++ linux-2.6.15.4/kernel/fork.c 2006-02-18 14:09:54.000000000 +0100 > @@ -43,6 +43,7 @@ > #include > #include > #include > +#include > > #include > #include > @@ -1141,6 +1142,7 @@ > write_unlock_irq(&tasklist_lock); > proc_fork_connector(p); > cpuset_fork(p); > + proc_root_notify(pid); > retval = 0; > > fork_out: > --- linux-2.6.15/include/linux/proc_fs.h 2006-01-03 04:21:10.000000000 +0100 > +++ linux-2.6.15.4/include/linux/proc_fs.h 2006-02-18 13:55:52.000000000 +0100 > @@ -4,6 +4,8 @@ > #include > #include > #include > +#include > +#include > #include > > /* > @@ -194,6 +196,13 @@ > remove_proc_entry(name,proc_net); > } > > +static inline void proc_root_notify (pid_t pid) > +{ > + char buf[20]; > + snprintf (buf, sizeof (buf), "%d", pid); > + fsnotify_mkdir (proc_mnt->mnt_root->d_inode, buf); > +} This shouldn't inlined. Don't put spaces between the function name and the ( > #else > > #define proc_root_driver NULL > @@ -224,6 +233,8 @@ > mode_t mode, struct proc_dir_entry *base, get_info_t *get_info) > { return NULL; } > > +static inline void proc_root_notify (pid_t pid) {} This can remain inlined in the header. > struct tty_driver; > static inline void proc_tty_register_driver(struct tty_driver *driver) {}; > static inline void proc_tty_unregister_driver(struct tty_driver *driver) {}; > diff -uNr -X linux-2.6.15/Documentation/dontdiff linux-2.6.15/fs/proc/base.c linux-2.6.15.4/fs/proc/base.c > --- linux-2.6.15/fs/proc/base.c 2006-01-03 04:21:10.000000000 +0100 > +++ linux-2.6.15.4/fs/proc/base.c 2006-02-19 10:44:28.000000000 +0100 > @@ -1945,6 +1945,7 @@ > if(proc_dentry != NULL) { > shrink_dcache_parent(proc_dentry); > dput(proc_dentry); > + fsnotify_nameremove (proc_dentry, 1); > } I wonder if this is racy - after the dput() we might no longer have a reference?