linux-kernel - Re: SMP read() stopping at memory page boundaries

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Message-ID: <20070620180500.6e2d600a@the-village.bc.nu>
Date:	Wed, 20 Jun 2007 18:05:00 +0100
From:	Alan Cox <alan@...rguk.ukuu.org.uk>
To:	Timo Sirainen <tss@....fi>
Cc:	Ray Lee <ray-lk@...rabbit.org>, linux-kernel@...r.kernel.org
Subject: Re: SMP read() stopping at memory page boundaries

> I thought this wouldn't happen when reading from local filesystems.
> Anyway, my real program was doing that, and it was still seeing partial
> data. But looks like I can't reproduce it in my test program with two
> pread()s, so I'll have to do some more debugging.

It will occur if you are reading as someone else changes the file size.
Use file locking, it exists for a reason ;)

Alan
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