nixpkgs/nixos/lib/make-btrfs-fs.nix
Silvan Mosberger 374e6bcc40 treewide: Format all Nix files
Format all Nix files using the officially approved formatter,
making the CI check introduced in the previous commit succeed:

  nix-build ci -A fmt.check

This is the next step of the of the [implementation](https://github.com/NixOS/nixfmt/issues/153)
of the accepted [RFC 166](https://github.com/NixOS/rfcs/pull/166).

This commit will lead to merge conflicts for a number of PRs,
up to an estimated ~1100 (~33%) among the PRs with activity in the past 2
months, but that should be lower than what it would be without the previous
[partial treewide format](https://github.com/NixOS/nixpkgs/pull/322537).

Merge conflicts caused by this commit can now automatically be resolved while rebasing using the
[auto-rebase script](8616af08d9/maintainers/scripts/auto-rebase).

If you run into any problems regarding any of this, please reach out to the
[formatting team](https://nixos.org/community/teams/formatting/) by
pinging @NixOS/nix-formatting.
2025-04-01 20:10:43 +02:00

73 lines
1.9 KiB
Nix

# Builds an btrfs image containing a populated /nix/store with the closure
# of store paths passed in the storePaths parameter, in addition to the
# contents of a directory that can be populated with commands. The
# generated image is sized to only fit its contents, with the expectation
# that a script resizes the filesystem at boot time.
{
pkgs,
lib,
# List of derivations to be included
storePaths,
# Whether or not to compress the resulting image with zstd
compressImage ? false,
zstd,
# Shell commands to populate the ./files directory.
# All files in that directory are copied to the root of the FS.
populateImageCommands ? "",
volumeLabel,
uuid ? "44444444-4444-4444-8888-888888888888",
btrfs-progs,
libfaketime,
fakeroot,
}:
let
sdClosureInfo = pkgs.buildPackages.closureInfo { rootPaths = storePaths; };
in
pkgs.stdenv.mkDerivation {
name = "btrfs-fs.img${lib.optionalString compressImage ".zst"}";
nativeBuildInputs = [
btrfs-progs
libfaketime
fakeroot
] ++ lib.optional compressImage zstd;
buildCommand = ''
${if compressImage then "img=temp.img" else "img=$out"}
set -x
(
mkdir -p ./files
${populateImageCommands}
)
mkdir -p ./rootImage/nix/store
xargs -I % cp -a --reflink=auto % -t ./rootImage/nix/store/ < ${sdClosureInfo}/store-paths
(
GLOBIGNORE=".:.."
shopt -u dotglob
for f in ./files/*; do
cp -a --reflink=auto -t ./rootImage/ "$f"
done
)
cp ${sdClosureInfo}/registration ./rootImage/nix-path-registration
touch $img
faketime -f "1970-01-01 00:00:01" fakeroot mkfs.btrfs -L ${volumeLabel} -U ${uuid} -r ./rootImage --shrink $img
if ! btrfs check $img; then
echo "--- 'btrfs check' failed for BTRFS image ---"
return 1
fi
if [ ${builtins.toString compressImage} ]; then
echo "Compressing image"
zstd -v --no-progress ./$img -o $out
fi
'';
}