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From: Al Viro <viro@ZenIV.linux.org.uk>
To: Eric Paris <eparis@redhat.com>
Cc: Evgeniy Polyakov <zbr@ioremap.net>,
	linux-kernel@vger.kernel.org, a.p.zijlstra@chello.nl,
	hch@infradead.org, akpm@linux-foundation.org,
	alan@lxorguk.ukuu.org.uk
Subject: Re: [RFC PATCH -v4 07/14] fsnotify: add in inode fsnotify markings
Date: Mon, 22 Dec 2008 13:43:00 +0000	[thread overview]
Message-ID: <20081222134300.GA21807@ZenIV.linux.org.uk> (raw)
In-Reply-To: <1229186110.29167.100.camel@localhost.localdomain>

On Sat, Dec 13, 2008 at 11:35:09AM -0500, Eric Paris wrote:

> So to find an entry we need to first grab the inode->i_lock and start to
> walk the inode->i_fsnotify_mark_entries list.  Since we hold the i_lock
> we are not allowed to grab any other locks nor are we allowed to change
> anything other than entry->i_list.  The secret sauce is that we actually
> move the entry from the inode list to a private list which we can walk
> and modify lockless.  Inside the event we actually have to use a
> different list, free_i_list, for this operation so nothing else that
> races with us can mess stuff up.  We run the entire inode we are trying
> to free all entries for an put the entries on the private list.  We do
> NOT modify event->inode.

And just what happens if #3 ("remove entry") hits us in the meanwhile?  Freed
object sitting on free_i_list?

  reply	other threads:[~2008-12-22 13:43 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-12-12 21:51 [RFC PATCH -v4 00/14] fsnotify, dnotify, and inotify Eric Paris
2008-12-12 21:51 ` [RFC PATCH -v4 01/14] filesystem notification: create fs/notify to contain all fs notification Eric Paris
2008-12-12 21:51 ` [RFC PATCH -v4 02/14] fsnotify: pass a file instead of an inode to open, read, and write Eric Paris
2008-12-12 21:51 ` [RFC PATCH -v4 03/14] fsnotify: sys_execve and sys_uselib do not call into fsnotify Eric Paris
2008-12-12 21:51 ` [RFC PATCH -v4 04/14] fsnotify: use the new open-exec hook for inotify and dnotify Eric Paris
2008-12-13 15:29   ` Christoph Hellwig
2008-12-12 21:51 ` [RFC PATCH -v4 05/14] fsnotify: unified filesystem notification backend Eric Paris
2008-12-13  2:54   ` Evgeniy Polyakov
2008-12-13 15:01     ` Eric Paris
2008-12-12 21:51 ` [RFC PATCH -v4 06/14] fsnotify: add group priorities Eric Paris
2008-12-12 21:51 ` [RFC PATCH -v4 07/14] fsnotify: add in inode fsnotify markings Eric Paris
2008-12-13  3:07   ` Evgeniy Polyakov
2008-12-13 16:35     ` Eric Paris
2008-12-22 13:43       ` Al Viro [this message]
2008-12-22 14:45         ` Eric Paris
2008-12-12 21:51 ` [RFC PATCH -v4 08/14] fsnotify: parent event notification Eric Paris
2008-12-12 21:52 ` [RFC PATCH -v4 09/14] dnotify: reimplement dnotify using fsnotify Eric Paris
2008-12-12 21:52 ` [RFC PATCH -v4 10/14] fsnotify: generic notification queue and waitq Eric Paris
2008-12-12 21:52 ` [RFC PATCH -v4 11/14] fsnotify: include pathnames with entries when possible Eric Paris
2008-12-13  3:19   ` Evgeniy Polyakov
2008-12-13 16:42     ` Eric Paris
2008-12-12 21:52 ` [RFC PATCH -v4 12/14] fsnotify: add correlations between events Eric Paris
2008-12-18 22:28   ` C. Scott Ananian
2008-12-22  2:40     ` Eric Paris
2008-12-22  9:01       ` Evgeniy Polyakov
2008-12-22 20:06       ` C. Scott Ananian
2008-12-12 21:52 ` [RFC PATCH -v4 13/14] inotify: reimplement inotify using fsnotify Eric Paris
2008-12-13  3:22   ` Evgeniy Polyakov
2008-12-13 16:44     ` Eric Paris
2008-12-15 15:48       ` Evgeniy Polyakov
2008-12-12 21:52 ` [RFC PATCH -v4 14/14] shit on top for debugging Eric Paris
2008-12-14 22:40   ` James Morris
2008-12-14 22:47     ` Eric Paris
2008-12-18 23:36 ` [RFC PATCH -v4 00/14] fsnotify, dnotify, and inotify C. Scott Ananian
2008-12-22  3:22   ` Eric Paris
2008-12-22 10:58     ` Niraj Kumar
2008-12-22 19:59     ` C. Scott Ananian
2008-12-22 20:53       ` Eric Paris
2008-12-29 18:19         ` C. Scott Ananian
2008-12-22 21:04       ` Al Viro
2008-12-22 23:08         ` C. Scott Ananian
2008-12-22 23:20           ` Al Viro
2008-12-22 23:21           ` Christoph Hellwig
2008-12-25 18:17             ` C. Scott Ananian
2008-12-25 20:33               ` Al Viro
2008-12-26  0:58                 ` C. Scott Ananian
2008-12-26  1:44                   ` Al Viro
2008-12-27 21:23                     ` C. Scott Ananian

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