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nixos/swap: fix creation on BTRFS and refactor assertions

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This commit is contained in:
oxalica 2022-10-04 11:08:59 +08:00
parent e24b481e0a
commit 87a0c9490d
1 changed files with 27 additions and 9 deletions
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36
nixos/modules/config/swap.nix
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@ -66,7 +66,7 @@ let
device = mkOption {
example = "/dev/sda3";
type = types.str;
type = types.nonEmptyStr;
description = lib.mdDoc "Path of the device or swap file.";
};
@ -197,6 +197,21 @@ in
};
config = mkIf ((length config.swapDevices) != 0) {
assertions = map (sw: {
assertion = sw.randomEncryption.enable -> builtins.match "/dev/disk/by-(uuid|label)/.*" sw.device == null;
message = ''
You cannot use swap device "${sw.device}" with randomEncryption enabled.
The UUIDs and labels will get erased on every boot when the partition is encrypted.
Use /dev/disk/by-partuuid/… instead.
'';
}) config.swapDevices;
warnings =
concatMap (sw:
if sw.size != null && hasPrefix "/dev/" sw.device
then [ "Setting the swap size of block device ${sw.device} has no effect" ]
else [ ])
config.swapDevices;
system.requiredKernelConfig = with config.lib.kernelConfig; [
(isYes "SWAP")
@ -205,24 +220,27 @@ in
# Create missing swapfiles.
systemd.services =
let
createSwapDevice = sw:
assert sw.device != "";
assert !(sw.randomEncryption.enable && lib.hasPrefix "/dev/disk/by-uuid" sw.device);
assert !(sw.randomEncryption.enable && lib.hasPrefix "/dev/disk/by-label" sw.device);
let realDevice' = escapeSystemdPath sw.realDevice;
in nameValuePair "mkswap-${sw.deviceName}"
{ description = "Initialisation of swap device ${sw.device}";
wantedBy = [ "${realDevice'}.swap" ];
before = [ "${realDevice'}.swap" ];
path = [ pkgs.util-linux ] ++ optional sw.randomEncryption.enable pkgs.cryptsetup;
path = [ pkgs.util-linux pkgs.e2fsprogs ]
++ optional sw.randomEncryption.enable pkgs.cryptsetup;
environment.DEVICE = sw.device;
script =
''
${optionalString (sw.size != null) ''
currentSize=$(( $(stat -c "%s" "${sw.device}" 2>/dev/null || echo 0) / 1024 / 1024 ))
if [ "${toString sw.size}" != "$currentSize" ]; then
dd if=/dev/zero of="${sw.device}" bs=1M count=${toString sw.size}
currentSize=$(( $(stat -c "%s" "$DEVICE" 2>/dev/null || echo 0) / 1024 / 1024 ))
if [[ ! -b "$DEVICE" && "${toString sw.size}" != "$currentSize" ]]; then
# Disable CoW for CoW based filesystems like BTRFS.
truncate --size 0 "$DEVICE"
chattr +C "$DEVICE" 2>/dev/null || true
dd if=/dev/zero of="$DEVICE" bs=1M count=${toString sw.size}
chmod 0600 ${sw.device}
${optionalString (!sw.randomEncryption.enable) "mkswap ${sw.realDevice}"}
fi