[bug#70770] [PATCH] deduplication: Detect holes and create sparse files.

[Ludovic Courtès]

Ludovic Courtès <ludo@gnu.org> skribis:

> This reduces disk usage of sparse files that are substituted such as
> Guile object files (ELF files).  As of Guile 3.0.9, .go files are sparse
> due to ELF sections being aligned on 64 KiB boundaries.
>
> This reduces disk usage reported by “du -sh” by 9% for the ‘guix’
> package, by 23% for ‘guile’, and by 35% for ‘guile-git’.
>
> * guix/store/deduplication.scm (hole-size, find-holes): New procedures.
> (tee)[seekable?]: New variable.
> [read!]: Add case when SEEKABLE? is true.
> * tests/store-deduplication.scm (cartesian-product): New procedure.
> ("copy-file/deduplicate, sparse files (holes: ~a/~a/~a)"): New test set.
>
> Change-Id: Iad2ab7830dcb1220e2026f4a127a6c718afa8964
> ---
>  guix/store/deduplication.scm  | 79 ++++++++++++++++++++++++++++++++++-
>  tests/store-deduplication.scm | 58 ++++++++++++++++++++++++-
>  2 files changed, 134 insertions(+), 3 deletions(-)

Pushed as 5a7cb59648d102168bd4ecd16f36b69e0f594be1.

We’ll have to update the ‘guix’ package for this to take effect.

Ludo’.