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Date: Tue, 08 Jul 2014 09:37:00 +0200
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Subject: Re: [PHP-DEV] Implemented fallocate() syscall in streams
From: ivan.enderlin@hoa-project.net ("Ivan Enderlin @ Hoa")

On 13/06/2014 16:20, Julien Pauli wrote:
> Hi,
Hello :-),


> I just wrote a patch to add fallocate() syscall support for streams.
> It relies on posix_fallocate(), so that it should support many Unixes.
> Linux's got a specification with a fallocate() function, more powerful
> than the posix call.
>
> fallocate() does write blocks to the underlying filesystem (not so
> many are supported, but the ones not supported should proxy to
> ftruncate()) and prevents sparse file creation whereas ftruncate()
> just updates inode information, leading to possible future out of
> space errors.
>
> I got a POC showing the diffs between both calls here :
> https://gist.github.com/jpauli/8afec7c4fc2b38f8ff27
>
> I propose two APIs for PHP :
> - One that adds a function : fallocate()
> https://github.com/jpauli/php-src/tree/fallocate
I prefer this one.


> - One that relies on ftruncate() , and adds a <bool>$use_fallocate
> flag https://github.com/jpauli/php-src/tree/fallocate_flag
>
> Please, note that the latest proposal requires patches in different
> extensions, as I changed a PHP_API function signature.
>
> I don't know if Windows can support that. Pierre, Anatol ? :-)
>
> Tests are beeing written at the moment.
>
> I didn't implement this is user stream handlers, as this really is a
> low level implementation design that is kind of useless for usage in
> user streams.
>
> Thoughts ?
If the first one is used, please, consider exposing it on the user-land 
of stream wrappers (exemple: `stream_allocate`) if possible.

Cheers.

-- 
Ivan Enderlin
Developer of Hoa
http://hoa-project.net/

PhD. student at DISC/Femto-ST (Vesontio) and INRIA (Cassis)
http://disc.univ-fcomte.fr/ and http://www.inria.fr/

Member of HTML and WebApps Working Group of W3C
http://w3.org/