[pacman-dev] Disk space checking branch "complete"

[Nezmer]

On Tue, Nov 16, 2010 at 06:06:32PM -0600, Dan McGee wrote:
> On Tue, Nov 16, 2010 at 5:36 PM, Allan McRae <allan at archlinux.org> wrote:
> > On 17/11/10 03:25, Nezmer wrote:
> >>
> >> On Tue, Nov 16, 2010 at 09:03:37PM +1000, Allan McRae wrote:
> >>>
> >>> On 16/11/10 18:02, Bryce Gibson wrote:
> >>>>
> >>>> Hi Allan,
> >>>> I just wanted to ask, it looks like your patches will make a sync fail
> >>>> if it
> >>>> finds there's not enough space, is that correct?
> >>>> Because I'd suggest a warning may be more appropriate, especially for
> >>>> use
> >>>> cases like compressed filesystems.
> >>>> Cheers
> >>>> Bryce
> >>>> ps. I noticed that space checking can be completely disabled via
> >>>> pacman.conf, which may be seen as a suitable solution for people in
> >>>> these
> >>>> types of situation.
> >>>
> >>> Disabling checking in pacman.conf is what I would recommend in these
> >>> sort of cases.  These are the sort of things we will only find out
> >>> after we get some widespread usage of the feature.  I would be
> >>> interested in what the size calculations actually do on compressed
> >>> filesystems.
> >>>
> >>> Allan
> >>>
> >>>
> >>
> >> On the topic of FS compression(also FS caching and delayed allocation).
> >>
> >> The real issue I had was the calculation of install size when building
> >> the package. The calculated size was always *very* small. I addressed
> >> this issue with 2 patches. The 1st one (adding sync before running du)
> >> didn't fix anything. The 2nd patch worked pretty well.
> >>
> >>
> >> http://gitorious.org/pacman-bsd/pacman-bsd/commit/8b367d4441ba85b5548285d987afcfc84c4fcb3e
> >>
> >> http://gitorious.org/pacman-bsd/pacman-bsd/commit/cf3341fe591293a493bc925e0433a1f696b37d90
> >
> > I think that initial "sync" is not needed because du does one anyway. The
> > second one looks interesting so I have bookmarked it to look at later.
> 
> We've putzed around with this a few times, haven't we? This basically
> "reverts" this one:
> 
> commit 149839c5391e9a93465f86dbb8d095a0150d755d
> Author: Xavier Chantry <shiningxc at gmail.com>
> Date:   Mon May 26 23:46:01 2008 +0200
> 
>     du -b is not available on BSD, use du -k instead.
> 
>     This fixes FS#10459.
> 
>     There is apparently no portable ways to get the apparent size of a file,
>     like du -b does. So the best compromise seems to get the block size in kB,
>     and then convert that to byte so that we keep compatibility.
> 
>     Signed-off-by: Xavier Chantry <shiningxc at gmail.com>
>     Signed-off-by: Dan McGee <dan at archlinux.org>
> 
> There are three or so file sizes that matter:
> 1) du -s : what we do now, sums up actual taken space so would be more
> accurate with many < 4K files.
> 2) du -sb: what we did before and what is proposed, sums up apparent
> size, so does not necessarily best represent installed size (either
> sparse files or many <4K files would throw the number off). The 4K
> assumption also may not always hold...
> 3) du --tell-me-how-many-blocks-but-not-compressed : what seems like
> perhaps the ideal? I'm not sure, but this would basically
>     for file in tree:
>         total += ceil(filesize to 4K)
> 
> 1 is the most portable; 2 we need different flags all over the place;
> 3 we definitely don't seem to be able to use exiting tools but this
> would not be an awful one to write.
> 
> -Dan
> 

Is this 3 ?

install_size=0
for f in `find $pkgdir -type f`; do
  (( s=$(${SIZECMD} ${f})/1024 ))
  (( $(${SIZECMD} ${f})%1024 > 0 )) && (( s++ ))
  (( $s < 4 )) && (( s=4 ))
  (( install_size+=${s} ))
done

Unfortunately, this takes around 39 seconds in a 13085 files package.