Toggle diff (245 lines)
diff --git a/doc/guix.texi b/doc/guix.texi
index 1081ed26a3..5ad3907dbe 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -13885,6 +13885,106 @@ a file system declaration such as:
compress-force=zstd,space_cache=v2"))
@end lisp
+@node ZFS file system
+@subsection ZFS file system
+
+The ZFS on Linux file system cannot legally be downloaded as part of the
+Linux kernel, but you as a user can do anything on hardware you own,
+including download ZFS as source code, compile ZFS as a kernel module,
+and link it into Linux.
+
+As a large and complex kernel module, ZFS has to be compiled for a
+specific version of Linux. Often the latest ZFS package available in Guix
+cannot be compiled with the latest Linux kernel available in Guix, so
+installing the @code{zfs} package in your system configuration file will
+fail.
+
+Instead, you have to check the
+@url{https://github.com/openzfs/zfs/releases,OpenZFS release notes} for
+the specific version of ZFS that Guix has packaged to determine what
+Linux kernels you can use, then check the @code{linux-libre} packages
+that Guix has packaged, and select one you can use on your system.
+
+Then, you have to modify your system configuration file, and create a
+ZFS package that compiles using the specific Linux version you chose.
+Below is a sketch of how you would modify your @code{operating-system}
+declaration in order to set up ZFS:
+
+@lisp
+(use-modules (gnu))
+;; @dots{}
+(use-service-modules
+ ; @dots{}
+ file-systems)
+(use-package-modules
+ ; @dots{}
+ linux
+ file-systems)
+
+;; @dots{}
+
+;;; (1) Select a specific kernel.
+(define system-kernel linux-libre-5.4)
+;;; (2) Define a ZFS package for your kernel.
+(define system-zfs (make-zfs-package system-kernel))
+
+;; @dots{}
+
+(operating-system
+ ;;; (3) Specify your selected kernel.
+ (kernel system-kernel)
+ ;;; (4) Add the "module" output of the system ZFS package to
+ ;;; the kernel-loadable modules.
+ (kernel-loadable-modules (list (list system-zfs "module")))
+
+ ;; @dots{}
+
+ (packages
+ ;;; (5) Add the system ZFS package to global packages so that
+ ;;; "zfs", "zpool" etc. commands are available.
+ (cons* system-zfs
+ ; @dots{}
+ %base-packages))
+
+ ;; @dots{}
+
+ (services
+ ;;; (6) Add a service that loads ZFS and all ZFS pools at boot.
+ (cons* (service zfs-loader-service-type
+ system-zfs)
+ ; @dots{}
+ %base-services))
+ ;; @dots{}
+ )
+@end lisp
+
+@deffn (Scheme Procedure) make-zfs-package @var{kernel}
+This procedure creates a package which, when included as a package
+in your system, can be loaded as a kernel module for the specified
+@var{kernel}, a Linux kernel package.
+It is intended to create a system-specific ZFS kernel module for
+the Linux kernel you will use in your system.
+@end deffn
+
+@deffn (Scheme Variable) zfs-loader-service-type
+This is the service that loads the ZFS kernel module and imports all
+ZFS pools. The value associated with @code{zfs-loader-service-type}
+services must be the ZFS package you defined for your system, and
+whose @code{"module"} output you have included as a loadable kernel
+module.
+@end deffn
+
+When you have modified your @code{operating-system} to include ZFS
+as in the above and reconfigured and rebooted, you will now be able
+to create, mount, and manage ZFS pools. At each boot, ZFS will
+automatically open any ZFS pools it detects in your system, and will
+mount ZFS pools that have a non-@code{legacy} mountpoint. If ZFS
+finds mountable ZFS filesystems that are encrypted by passphrase, it
+will prompt for passphrases on the console.
+
+ZFS as root filesystem is not supported yet. ZFS for @code{/home} is
+also probably not easily doable yet.
+
@node Mapped Devices
@section Mapped Devices
diff --git a/gnu/local.mk b/gnu/local.mk
index c03a8b9f51..e59a3bb9f7 100644
--- a/gnu/local.mk
+++ b/gnu/local.mk
@@ -601,6 +601,7 @@ GNU_SYSTEM_MODULES = \
%D%/services/dict.scm \
%D%/services/dns.scm \
%D%/services/docker.scm \
+ %D%/services/file-systems.scm \
%D%/services/authentication.scm \
%D%/services/games.scm \
%D%/services/ganeti.scm \
diff --git a/gnu/packages/file-systems.scm b/gnu/packages/file-systems.scm
index 895ad069c5..e8f49a59fa 100644
--- a/gnu/packages/file-systems.scm
+++ b/gnu/packages/file-systems.scm
@@ -944,16 +944,37 @@ APFS.")
("openssl" ,openssl)
("python" ,python)
("python-cffi" ,python-cffi)
- ("util-linux" ,util-linux "lib")
+ ("util-linux" ,util-linux)
+ ("util-linux-lib" ,util-linux "lib")
("zlib" ,zlib)))
(home-page "https://zfsonlinux.org/")
(synopsis "Native ZFS on Linux")
(description
"ZFS on Linux is an advanced file system and volume manager which was
originally developed for Solaris and is now maintained by the OpenZFS
-community.")
+community.
+
+DO NOT INSTALL THIS PACKAGE. Instead, refer to the 'ZFS file system' section
+of the Guix info manual for how to install ZFS.")
(license license:cddl1.0)))
+(define-public (make-zfs-package kernel)
+ (package
+ (inherit zfs)
+ (name (string-append "zfs-for-"
+ (package-name kernel)
+ "-"
+ (package-version kernel)
+ "-version"))
+ (arguments
+ (cons* #:linux kernel (package-arguments zfs)))
+ (description
+ "ZFS on Linux is an advanced file system and volume manager which was
+originally developed for Solaris and is now maintained by the OpenZFS
+community.
+
+This package has been compiled for a specific Linux kernel.")))
+
(define-public mergerfs
(package
(name "mergerfs")
diff --git a/gnu/services/file-systems.scm b/gnu/services/file-systems.scm
new file mode 100644
index 0000000000..bdc33f4028
--- /dev/null
+++ b/gnu/services/file-systems.scm
@@ -0,0 +1,72 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2021 raid5atemyhomework <raid5atemyhomework@protonmail.com>
+;;;
+;;; This file is part of GNU Guix.
+;;;
+;;; GNU Guix is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; GNU Guix is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (gnu services file-systems)
+ #:use-module (guix gexp)
+ #:use-module (gnu services)
+ #:use-module (gnu services shepherd))
+
+;;; ZFS
+(define (zfs-loader-shepherd-service system-zfs)
+ (let* ((zpool (file-append system-zfs "/sbin/zpool")))
+ (list
+ (shepherd-service
+ (documentation "Load ZFS kernel module and import ZFS pools.")
+ (provision '(zfs-loader))
+ (requirement '(file-systems))
+ (one-shot? #t)
+ (modules `((srfi srfi-1)
+ (srfi srfi-34)
+ (srfi srfi-35)
+ (rnrs io ports)
+ ,@%default-modules))
+ (start #~(lambda _
+ (if (not (file-exists? "/proc/sys/kernel/modprobe"))
+ (begin (format (current-error-port) "error: ~a~%"
+ "Kernel is missing loadable module support.")
+ #f)
+ (and
+ (let ((modprobe (call-with-input-file
+ "/proc/sys/kernel/modprobe" get-line)))
+ (guard (c ((message-condition? c)
+ (format (current-error-port)
+ "error loading 'zfs' kernel module: ~a~%"
+ (condition-message c))
+ #f))
+ (invoke/quiet modprobe "--" "zfs")))
+ (guard (c ((message-condition? c)
+ (format (current-error-port)
+ "error importing zpools: ~a~%"
+ (condition-message c))
+ #f))
+ ;; 'current-output-port' is typically connected to /dev/klog
+ ;; in PID 1, so redirect it to the console so we are talking
+ ;; to the user if zpool sees an encrpyted fs that needs a
+ ;; passphrase.
+ (with-output-to-port (current-error-port)
+ (lambda ()
+ (invoke #$zpool "import" "-a" "-l"))))))))))))
+
+(define-public zfs-loader-service-type
+ (service-type
+ (name 'zfs-loader)
+ (description "Load ZFS kernel module and import ZFS pools.")
+ (extensions
+ (list (service-extension shepherd-root-service-type zfs-loader-shepherd-service)
+ (service-extension user-processes-service-type (const '(zfs-loader)))))))
+
