Files smaller than 8 KiB typically represent ~70% of the entries in
/gnu/store/.links but only contribute to ~4% of the space savings
afforded by deduplication.
Not considering these files for deduplication speeds up file insertion
in the store and, more importantly, leaves 'removeUnusedLinks' with
fewer entries to traverse, thereby speeding it up proportionally.
Partly fixes <https://issues.guix.gnu.org/24937>.
* config-daemon.ac: Remove symlink hard link check and CAN_LINK_SYMLINK
definition.
* guix/store/deduplication.scm (%deduplication-minimum-size): New
variable.
(deduplicate)[loop]: Do not recurse when FILE's size is below
%DEDUPLICATION-MINIMUM-SIZE.
(dump-port): New procedure.
(dump-file/deduplicate)[hash]: Turn into...
[dump-and-compute-hash]: ... this thunk.
Call 'deduplicate' only when SIZE is greater than
%DEDUPLICATION-MINIMUM-SIZE; otherwise call 'dump-port'.
* nix/libstore/gc.cc (LocalStore::removeUnusedLinks): Drop files where
st.st_size < deduplicationMinSize.
* nix/libstore/local-store.hh (deduplicationMinSize): New declaration.
* nix/libstore/optimise-store.cc (deduplicationMinSize): New variable.
(LocalStore::optimisePath_): Return when PATH is a symlink or smaller
than 'deduplicationMinSize'.
* tests/derivations.scm ("identical files are deduplicated"): Produce
files bigger than %DEDUPLICATION-MINIMUM-SIZE.
* tests/nar.scm ("restore-file-set with directories (signed, valid)"):
Likewise.
* tests/store-deduplication.scm ("deduplicate, below %deduplication-minimum-size"):
New test.
("deduplicate", "deduplicate, ENOSPC"): Produce files bigger than
%DEDUPLICATION-MINIMUM-SIZE.
* tests/store.scm ("substitute, deduplication"): Likewise.
This avoids repeated (mkdir-p "/gnu/store/.links") calls when
deduplicating lots of files.
* guix/store/deduplication.scm (deduplicate): Remove initial call to
'mkdir-p'. Add ENOENT case in 'link' exception handler. Reindent.
* tests/store-deduplication.scm ("deduplicate, ENOSPC"): Check
for (<= links 4) to account for the initial 'link' call.
Until now deduplication was performed as an additional pass after
copying files, which involve re-traversing all the files that had just
been copied.
* guix/store/deduplication.scm (copy-file/deduplicate): New procedure.
* tests/store-deduplication.scm ("copy-file/deduplicate"): New test.
* guix/build/store-copy.scm (populate-store): Add #:deduplicate?
parameter and honor it.
* tests/gexp.scm ("gexp->derivation, store copy"): Pass #:deduplicate? #f
to 'populate-store'.
* gnu/build/image.scm (initialize-root-partition): Pass #:deduplicate?
to 'populate-store'. Pass #:deduplicate? #f to 'register-closure'.
* gnu/build/vm.scm (root-partition-initializer): Likewise.
* gnu/build/install.scm (populate-single-profile-directory): Pass
#:deduplicate? #f to 'populate-store'.
* gnu/build/linux-initrd.scm (build-initrd): Likewise.
* guix/scripts/pack.scm (self-contained-tarball)[import-module?]: New
procedure.
[build]: Pass it as an argument to 'source-module-closure'.
* guix/scripts/pack.scm (squashfs-image)[build]: Wrap in
'with-extensions'.
* gnu/system/linux-initrd.scm (expression->initrd)[import-module?]: New
procedure.
[builder]: Pass it to 'source-module-closure'.
* gnu/system/install.scm (cow-store-service-type)[import-module?]: New
procedure. Pass it to 'source-module-closure'.
Reported by Andreas Enge <andreas@enge.fr>
in <https://bugs.gnu.org/33676>.
* guix/store/deduplication.scm (replace-with-link): Catch ENOSPC around
'get-temp-link'. Do nothing when 'get-temp-link' throws ENOSPC. Move
code to restore PARENT's permissions outside of 'catch'.
* tests/store-deduplication.scm ("deduplicate, ENOSPC"): New test.
Previously they'd always be placed next to TO-REPLACE, which would lead
to EPERM in some cases.
* guix/store/deduplication.scm (replace-with-link): Add #:swap-directory
parameter and honor it. Add call to 'make-file-writable'. Catch
'system-error' around 'rename-file'.
(deduplicate): Pass #:swap-directory and remove uses of
'false-if-system-error'.
* tests/store-deduplication.scm ("deduplicate"): Add 'chmod' call.
* guix/store/deduplication.scm (get-temp-link): Turn 'args' in the 'catch'
handler into a rest argument.
(deduplicate): Use 'lstat' instead of 'file-is-directory?' to properly
handle symlinks. When iterating over the result of 'scandir', exclude
the ".links" sub-directory.
* tests/store-deduplication.scm ("deduplicate"): Create sub-directories
and call 'deduplicate' directly on STORE.
