Re: The *right* algorithm for determining the amount of free space

[Hugo Mills <hugo@carfax.org.uk>]

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On Fri, Mar 11, 2016 at 10:17:03PM +0000, Hugo Mills wrote:
>    I know I promised this a while ago and didn't get round to it, but
> Henk's tinkering reminded me of it. I note specifically that the
> algorithm used to give the free space to plain old df gives incorrect
> results -- probably because it's not using the algorithm below.
> 
>    There is an algorithm that (seems to) give the correct number of
> block groups which can be allocated, given a current allocation state
> of the FS. I haven't been able to prove it correct, but it seems to
> work. Here's some pseudocode for it:

   I forgot to mention, there's a JavaScript implementation of this
algorithm at:

http://carfax.org.uk/btrfs-usage/js/btrfs-usage.js

   Hugo.

-- 
Hugo Mills             | You can play with your friends' privates, but you
hugo@... carfax.org.uk | can't play with your friends' childrens' privates.
http://carfax.org.uk/  |
PGP: E2AB1DE4          |                                       C++ coding rule

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