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From: Al Viro <viro@ZenIV.linux.org.uk>
To: majianpeng <majianpeng@gmail.com>
Cc: john <john@johnmccutchan.com>, rlove <rlove@rlove.org>,
	eparis <eparis@parisplace.org>,
	linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [BUG] Using inotify on /proc/partitoins
Date: Fri, 14 Jun 2013 03:05:23 +0100	[thread overview]
Message-ID: <20130614020523.GL4165@ZenIV.linux.org.uk> (raw)
In-Reply-To: <201306140926455537935@gmail.com>

On Fri, Jun 14, 2013 at 09:26:49AM +0800, majianpeng wrote:
> Hi all,
>      I wanted to monitor /proc/partitions using inotify.


That, indeed, is a bug.  Easily fixed - don't do that.

> But when i call 'cat /proc/partitions',the program can't return.
> So i added some message in kernel in order to find the reason.
> In procfs for some files, the inode used this method to alloc.
> proc_lookup-->proc_lookup_de--->proc_get_inode-->new_inode_pseudo
> In new_inode_pseudo, it will alloc new inode so every open-operation procfs will alloc new inode.
> So inotify can't work.

Of course, it can't work.  Inotify if a kludge that kinda-sorta works
for local disk-backed filesystems, if you do not mind a pile of races.
For anything else it's completely worthless.

      reply	other threads:[~2013-06-14  2:05 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-06-14  1:26 [BUG] Using inotify on /proc/partitoins majianpeng
2013-06-14  2:05 ` Al Viro [this message]

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