From mboxrd@z Thu Jan  1 00:00:00 1970
From: Michael Raskin <7c6f434c@mail.ru>
Subject: Re: [BUG] fallocate behavior when crossing end-of-file
Date: Wed, 06 May 2009 19:12:04 +0400
Message-ID: <4A01A8C4.20205@mail.ru>
References: <4A018A90.7050109@mccme.ru> <4A01A5DF.5050406@gmail.com>
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Cc: linux-btrfs@vger.kernel.org
To: Edward Shishkin <edward.shishkin@gmail.com>
Return-path: <linux-btrfs-owner@vger.kernel.org>
In-Reply-To: <4A01A5DF.5050406@gmail.com>
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Edward Shishkin wrote:
>> Desired: something (probably, one block) is allocated/reserved for the
>> file. File length is set to 1 byte.
>              
> Where is it documented?
> 
> IMHO we should only guarantee that writes
> to [0, 1] won't fail because of lack of disk space.
> Other things (including file size) are up to implementation.

POSIX, SUS.

http://www.opengroup.org/onlinepubs/009695399/functions/posix_fallocate.html

<<<
If the offset+ len is beyond the current file size, then
posix_fallocate() shall adjust the file size to offset+ len. Otherwise,
the file size shall not be changed.
>>>

Michael Raskin
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