Bcachefs: Difference between revisions

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VisualWikitext

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-[https://bcachefs.org Bcachefs] is a next-generation CoW filesystem that aims to provide features from [[Btrfs]] and [[ZFS]] with a cleaner codebase, more stability, greater speed and a GPL-compatible license. It is built upon Bcache and is mainly developed by Kent Overstreet.
+[https://bcachefs.org Bcachefs] is a next-generation CoW filesystem that aims to provide features from [[Btrfs]] and [[ZFS]] with a cleaner codebase<ref name=":0">citation needed</ref>, more stability<ref name=":0" />, greater speed<ref name=":0" /> and a GPL-compatible license. It is built upon Bcache and is mainly developed by Kent Overstreet.
 == Installation ==
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      --label=hdd.hdd3 /dev/sde \
      --label=ssd.ssd1 /dev/sdf \
-     --label=ssd.ssd2 /dev/sdg
+     --label=ssd.ssd2 /dev/sdg \
      --foreground_target=ssd \
      --promote_target=ssd \
@@ Line 71: / Line 71: @@
      --label=hdd.hdd3 /dev/sde \
      --label=ssd.ssd1 /dev/sdf \
-     --label=ssd.ssd2 /dev/sdg
+     --label=ssd.ssd2 /dev/sdg \
      --foreground_target=ssd \
      --promote_target=ssd \
@@ Line 82: / Line 82: @@
 <syntaxhighlight lang="console">
 # bcachefs subvolume snapshot /mnt /mnt/snap1
+</syntaxhighlight>
+Filesystem check, fix errors and corruptions where a Bcachefs filesystem is on <code>/dev/sda</code>:
+<syntaxhighlight lang="console">
+# bcachefs fsck /dev/sda
+</syntaxhighlight>Change partition encryption password for <code>/dev/sda1</code><syntaxhighlight lang="console">
+# bcachefs set-passphrase /dev/sda1
 </syntaxhighlight>
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 == Tips and tricks ==
-=== Generate bcachefs enabled installation media ===
-Use following Nix [[Flakes|Flake-expression]] to generate a ISO installation image with a bcachefs enabled kernel
-{{file|flake.nix|nix|<nowiki>
-{
-  description = "Bcachefs enabled installation media";
-  inputs.nixos.url = "nixpkgs/nixos-23.11";
-  outputs = { self, nixos }: {
-    nixosConfigurations = {
-      exampleIso = nixos.lib.nixosSystem {
-        system = "x86_64-linux";
-        modules = [
-          "${nixos}/nixos/modules/installer/cd-dvd/installation-cd-minimal-new-kernel-no-zfs.nix"
-          ({ lib, pkgs, ... }: {
-            boot.supportedFilesystems = [ "bcachefs" ];
-            boot.kernelPackages = lib.mkOverride 0 pkgs.linuxPackages_latest;
-          })
-        ];
-      };
-    };
-  };
-}
-</nowiki>}}
-The following commands will generate the iso-image which will be available in the directory <code>./result/iso</code>
-<syntaxhighlight lang="console">
-# git init
-# git add flake.nix
-# nix build .#nixosConfigurations.exampleIso.config.system.build.isoImage
-</syntaxhighlight>
 === NixOS installation on bcachefs ===
@@ Line 158: / Line 133: @@
 <syntaxhighlight lang="console">
 # mkfs.fat -F 32 -n boot /dev/sda1
+# nix shell -p bcachefs-tools
 # mkfs.bcachefs -L nixos /dev/sda2
 </syntaxhighlight>
-In case you want to enable filesystem encryption, there's a workaround for [https://github.com/NixOS/nixpkgs/issues/32279 a bug] affecting NixOS 23.11. Formatting and unlocking the encrypted partition would look like this
+Formatting and unlocking the encrypted partition would look like this
 <syntaxhighlight lang="console">
-# nix-env -iA nixos.keyutils
+# nix-shell -p keyutils --run 'keyctl link @u @s'
-# keyctl link @u @s
+# nix-shell -p bcachefs-tools
 # bcachefs format --encrypted /dev/sda2
 # bcachefs unlock /dev/sda2
@@ Line 189: / Line 165: @@
 Continue installation as recommended by the [https://nixos.org/manual/nixos/stable/index.html#ch-installation NixOS manual].
-Before <code>nixos-install</code> you'll have to adapt the generated NixOS configuration to also use the latest Linux kernel supporting Bcachefs. Add the following line to the <code>configuration.nix</code> in your installation root (/mnt):
+=== Remote encrypted disk unlocking ===
+See article on [[Remote disk unlocking#Bcachefs unlocking|remote disk unlocking]] for a guide on how to enable SSH decryption of Bcachefs enabled systems.
+=== Automatically mount encrypted device on boot ===
+Since the Bcachefs mount options do [https://github.com/koverstreet/bcachefs-tools/pull/266 not support supplying a key file yet], we could use the <code>bcachefs</code> command and run it on boot using a [[Systemd]] unit:<syntaxhighlight lang="nix">
+systemd.services."bcachefs-mount" = {
+  after = [ "local-fs.target" ];
+  wantedBy = [ "multi-user.target" ];
+  environment = {
+    DEVICE_PATH = "/dev/sda1";
+    MOUNT_POINT = "/mnt";
+  };
+  script = ''
+    #!${pkgs.runtimeShell} -e
+    ${pkgs.keyutils}/bin/keyctl link @u @s
-{{file|/mnt/etc/nixos/configuration.nix|nix|<nowiki>
+    # Check if the device path exists
-boot.supportedFilesystems = [ "bcachefs" ];
+    if [ ! -b "$DEVICE_PATH" ]; then
-boot.kernelPackages = pkgs.linuxPackages_latest;
+      echo "Error: Device path $DEVICE_PATH does not exist."
-</nowiki>}}
+      exit 1
+    fi
+    # Check if the drive is already mounted
+    if ${pkgs.util-linux}/bin/mountpoint -q "$MOUNT_POINT"; then
+      echo "Drive already mounted at $MOUNT_POINT. Skipping..."
+      exit 0
+    fi
+    # Wait for the device to become available
+    while [ ! -b "$DEVICE_PATH" ]; do
+      echo "Waiting for $DEVICE_PATH to become available..."
+      sleep 5
+    done
+    # Mount the device
+    ${pkgs.bcachefs-tools}/bin/bcachefs mount -f /etc/keyfile_test "$DEVICE_PATH" "$MOUNT_POINT"
+  '';
+  serviceConfig = {
+    Type = "oneshot";
+    User = "root";
+  };
+};
+</syntaxhighlight>This example unit mounts the Bcachefs encrypted partition <code>/dev/sda1</code> to the target <code>/mnt</code> by using the key file <code>/etc/keyfile_test</code>.
 [[Category:Filesystem]]