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From: "H. Peter Anvin" <hpa@zytor.com>
To: Pavel Machek <pavel@ucw.cz>
Cc: Miklos Szeredi <miklos@szeredi.hu>,
	akpm@linux-foundation.org, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org, util-linux-ng@vger.kernel.org,
	linuxram@us.ibm.com, viro@ftp.linux.org.uk, hch@infradead.org,
	a.p.zijlstra@chello.nl
Subject: Re: [RFC][PATCH] VFS: create /proc/<pid>/mountinfo
Date: Wed, 23 Jan 2008 11:02:53 -0800	[thread overview]
Message-ID: <47978F5D.8010006@zytor.com> (raw)
In-Reply-To: <20080123134926.GB4059@ucw.cz>

Pavel Machek wrote:
> On Sun 2008-01-20 09:23:00, Miklos Szeredi wrote:
>>> Miklos Szeredi wrote:
>>>> - for mount ID's use IDA (from the IDR library) instead of a 32bit
>>>>   counter, which could overflow
>>> IDAs tend to get reused quickly, which can cause race conditions.  Any 
>>> reason not to just use a 64-bit counter?
>> They tend to become hard to parse/compare for humans after a while.
>> And all this is basically only for humans, so race conditions don't
>> really matter.  Also a changed mount with a reused ID is easily
>> identified by comparing the other fields.
> 
> Hmm, smart humans only compare last few digits if they don't care
> about 100% reliability, and dumb software compares 64bits easily...
> 							Pavel

Indeed.

And this is most certainly NOT only for humans, and race conditions most 
certainly matter.

	-hpa

  reply	other threads:[~2008-01-23 19:17 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-01-19 11:05 [RFC][PATCH] VFS: create /proc/<pid>/mountinfo Miklos Szeredi
2008-01-20  5:41 ` H. Peter Anvin
2008-01-20  8:23   ` Miklos Szeredi
2008-01-20  8:23     ` Miklos Szeredi
2008-01-23 13:49     ` Pavel Machek
2008-01-23 19:02       ` H. Peter Anvin [this message]
2008-01-23 19:32         ` Miklos Szeredi
2008-01-20 11:20 ` Jan Engelhardt
2008-01-20 12:20   ` Miklos Szeredi
2008-01-20 12:20     ` Miklos Szeredi
2008-01-21 19:48 ` Ram Pai
2008-01-21 19:48   ` Ram Pai
2008-01-21 21:25   ` Miklos Szeredi
2008-01-21 21:53     ` Ram Pai
2008-01-21 21:53       ` Ram Pai
2008-01-21 22:09       ` Miklos Szeredi
2008-01-21 22:09         ` Miklos Szeredi
2008-01-22 20:56         ` Serge E. Hallyn
2008-01-22 20:56           ` Serge E. Hallyn

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