linux-kernel - Re: Write is not atomic?

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Message-ID: <CAMo8BfLp2e_sO=3-++TkjxiUm_syTuxndj5H37YLddYqk-54tg@mail.gmail.com>
Date:	Tue, 16 Oct 2012 03:42:52 +0400
From:	Max Filippov <jcmvbkbc@...il.com>
To:	Philippe Troin <phil@...i.org>
Cc:	Dave Chinner <david@...morbit.com>,
	Juliusz Chroboczek <jch@....jussieu.fr>,
	linux-kernel@...r.kernel.org
Subject: Re: Write is not atomic?

On Tue, Oct 16, 2012 at 3:24 AM, Philippe Troin <phil@...i.org> wrote:
> On Tue, 2012-10-16 at 10:13 +1100, Dave Chinner wrote:
>> On Mon, Oct 15, 2012 at 11:36:15PM +0200, Juliusz Chroboczek wrote:
>> > The following fragment of code
>> >
>> >     int fd;
>> >     fd = open("exemple", O_CREAT | O_WRONLY | O_TRUNC, 0666);
>> >     fork();
>> >     write(fd, "Ouille", 6);
>> >     close(fd);
>
> can be replaced with:
>
>         int fd;
>         fd = open("exemple", O_CREAT | O_WRONLY | O_TRUNC | O_APPEND, 0666);
>         fork();
>         write(fd, "Ouille", 6);
>         close(fd);

Fails the same way as the original. I guess O_APPEND doesn't work this way
for writes to the shared file descriptor.

-- 
Thanks.
-- Max
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