Re: reiser4 plugins

Artem B. Bityuckiy
2005-06-27T07:27:33Z

Valdis.Kletnieks@vt.edu wrote:
> For more fun, consider how you can write 1 megabyte of data to a file,
> lseek to the beginning and start writing again - and you go over quota
> on the *second* write even though you're over-writing already existing
> data. Can happen if you're compressing, and the second write doesn't
> compress as well as the first. (To be fair, we already have similar
> issues with sparse files - but at least 'tar --sparse' has an easy way
> to deal with it compared to this. ;)
Sorry, may be I'm out of the context, but here is my view.

In case of compression in the kernel space you may take into account the
size of file in the _uncompressed_ form and how much it takes in the
compressed form - doesn't matter. So, no problems with rewriting.

Moreover, are you sure that the current quota model is enough for FSes
with on-fligh compression? The model should probably be extended/changed.

Problems with quota and accounting is not the reason to forbid the
on-flight compression. And they don't have to co-exist well.

--
Best Regards,
Artem B. Bityuckiy,
St.-Petersburg, Russia.