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From: raid5atemyhomework <raid5atemyhomework@protonmail.com>
To: "guix-devel@gnu.org" <guix-devel@gnu.org>
Subject: Re: ZFS on Guix
Date: Wed, 06 Jan 2021 05:20:23 +0000	[thread overview]
Message-ID: <Zd8uMcxWfNY1RxDn4gwrCZjHKAUxSQgcuBsNDAqa0tMqj_ufQWE-URr7L49OBWMGDfQB8v_8eRdnhlsZTxU0Xq_F6tu-92jvvc1lSh-2tdA=@protonmail.com> (raw)
In-Reply-To: <t_t9LHglTTJw2Bhtd2xX4JCJeZBi5Drqg0t04vJsfRLfoENqpftZcuHO8LYi2AO05P71lbbCgQC5etCDiPsdcssJmw1pHGyCY3gUT-9w9_o=@protonmail.com>

Hi guix-developers,

Another issue here is that ZFS prefers to not be managed via `/etc/fstab`/`mount`/`umount`.  Instead, at startup ZFS magically imports ZFS pools and mounts ZFS datasets in the correct place, as configured in the `mountpoint` properties of the dataset.  This magic is actually implemented by executing `zpool import -a` at startup after ZFS module loading.  Note that `zpool import -a` has to be executed always so that ZFS can detect its pools, though the automatic mounting can be suppressed with `zpool import -a -N`.

(`systemd`-based distros have a number of `systemd` services that handle ZFS importation by use of a `/etc/zfs/zpool.cache` file that ZFS maintains, and then does `zfs mount -a` to do automounting, but I'll leave that for later.)

Now, properly speaking, the shepherd `file-systems` service should not be started until we have actually performed ZFS automounting.  This means that `file-systems` has to have as a requirement the ZFS shepherd service that implements the automounting.  And of course it should *not* require that if ZFS isn't installed in the system.

So, I made another patch that makes the `file-systems` shepherd service have an extensible set of requirements, like `user-processes` does.  It's below.  Actual `file-system`s declared in the operating system then make themselves requirements of `file-systems`.  Then, a ZFS automounting shepherd service can be installed by the `zfs-service-type` and added as a requirement of the `file-systems` shepherd service.

This is important since one possible use of ZFS is to have it provide the `/home` filesystem.  And the `/home` filesystem has to be mounted before `user-homes` shepherd service starts.  So the ZFS automounting shepherd service has to be a requirement of `file-systems`, which is enabled by the below.

Please review!


From 792a8f8efc95e4fe9a94d42f839ddcfb034b8540 Mon Sep 17 00:00:00 2001
From: raid5atemyhomework <raid5atemyhomework@protonmail.com>
Date: Wed, 6 Jan 2021 08:15:54 +0800
Subject: [PATCH] gnu: Make file-systems target extensible by services.

* gnu/services/base.scm (file-system-shepherd-services): Move file-systems
shepherd service to ...
(file-systems-target-shepherd-services): ... new procedure here.
(file-systems-target-service-type): New variable.
(file-system-service-type): Extend file-systems-target service to add each
file-system as a requirement.
* gnu/system.scm (operating-system-default-essential-services): Instantiate
file-systems-target-service-type.
(hurd-default-essential-services): Instantiate file-systems-target-service-type.
---
 gnu/services/base.scm | 37 +++++++++++++++++++++++++++----------
 gnu/system.scm        |  2 ++
 2 files changed, 29 insertions(+), 10 deletions(-)

diff --git a/gnu/services/base.scm b/gnu/services/base.scm
index 945b546607..13cfb6a8a2 100644
--- a/gnu/services/base.scm
+++ b/gnu/services/base.scm
@@ -13,6 +13,7 @@
 ;;; Copyright © 2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
 ;;; Copyright © 2020 Florian Pelz <pelzflorian@pelzflorian.de>
 ;;; Copyright © 2020 Brice Waegeneire <brice@waegenei.re>
+;;; Copyright © 2021 raid5atemyhomework <raid5atemyhomework@protonmail.com>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -67,6 +68,7 @@
   #:export (fstab-service-type
             root-file-system-service
             file-system-service-type
+            file-systems-target-service-type
             swap-service
             host-name-service
             console-keymap-service
@@ -362,18 +364,29 @@ FILE-SYSTEM."
                        (gnu system file-systems)
                        ,@%default-modules)))))))

+(define (file-systems-target-shepherd-services requirements)
+  (list
+    (shepherd-service
+      (provision '(file-systems))
+      (requirement (cons* 'root-file-system 'user-file-systems requirements))
+      (documentation "Target for all the initially-mounted file systems")
+      (start #~(const #t))
+      (stop #~(const #t)))))
+(define file-systems-target-service-type
+  (service-type
+    (name 'file-systems)
+    (extensions (list (service-extension shepherd-root-service-type
+                                         file-systems-target-shepherd-services)))
+    (compose concatenate)
+    (extend append)
+    ;; Extensions can add new values to this list.
+    (default-value '())
+    (description "The @code{file-systems} service is the target that is started
+when all file systems have been mounted.")))
+
 (define (file-system-shepherd-services file-systems)
   "Return the list of Shepherd services for FILE-SYSTEMS."
   (let* ((file-systems (filter file-system-mount? file-systems)))
-    (define sink
-      (shepherd-service
-       (provision '(file-systems))
-       (requirement (cons* 'root-file-system 'user-file-systems
-                           (map file-system->shepherd-service-name
-                                file-systems)))
-       (documentation "Target for all the initially-mounted file systems")
-       (start #~(const #t))
-       (stop #~(const #f))))

     (define known-mount-points
       (map file-system-mount-point file-systems))
@@ -403,7 +416,7 @@ FILE-SYSTEM."
                            (filter (negate known?) (mount-points)))
                  #f))))

-    (cons* sink user-unmount
+    (cons* user-unmount
            (map file-system-shepherd-service file-systems))))

 (define (file-system-fstab-entries file-systems)
@@ -431,6 +444,10 @@ FILE-SYSTEM."
                        (service-extension fstab-service-type
                                           file-system-fstab-entries)

+                       ;; Have 'file-systems' depend on each declared file system.
+                       (service-extension file-systems-target-service-type
+                                          (cut map file-system->shepherd-service-name <>))
+
                        ;; Have 'user-processes' depend on 'file-systems'.
                        (service-extension user-processes-service-type
                                           (const '(file-systems)))))
diff --git a/gnu/system.scm b/gnu/system.scm
index 5c530f176e..6987641ee8 100644
--- a/gnu/system.scm
+++ b/gnu/system.scm
@@ -667,6 +667,7 @@ bookkeeping."
                     (operating-system-setuid-programs os))
            (service profile-service-type
                     (operating-system-packages os))
+           (service file-systems-target-service-type)
            other-fs
            (append mappings swaps

@@ -691,6 +692,7 @@ bookkeeping."
                                    (operating-system-groups os))
                            (operating-system-skeletons os))
           (root-file-system-service)
+          (service file-systems-target-service-type)
           (service file-system-service-type '())
           (service fstab-service-type
                    (filter file-system-needed-for-boot?
--
2.29.2



  reply	other threads:[~2021-01-06  5:20 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-02  6:16 ZFS on Guix raid5atemyhomework
2021-01-02  6:40 ` raid5atemyhomework
2021-01-03 15:50   ` Danny Milosavljevic
     [not found]     ` <Kyzl4xnRrDtWbTkAmBf1i8mtSZvu-AYatdazY1NsABFAzqqi7HQl-t0d2LWAInr8n7KxGyJWfIfTWqrefrxdgWelKbr2SWc9ATV5P8zrVtw=3D@protonmail.com>
     [not found]       ` <DmzbKm-kVn1tCfYc4eAXeEEbj3RN28qvXJaLL6dHtBBeNdXE-e-vN-a4Y-De38H8jI5lt19mauUTz9k0JArMyOT2ciYoxKY8mXFw3xeHGqo=3D@protonmail.com>
     [not found]         ` <guGWV=5FuA7tRqi0SzCiial7b5W7uKlmcMRhQXIlhtzyf1Fgq91eakr8d5EQrZ2fJPJK1OqKMCJfMgE2H4SjRSph-31ms=5F2g-mFiddv9ppiaQ=3D@protonmail.com>
2021-01-04  0:50     ` raid5atemyhomework
2021-01-04  1:15       ` raid5atemyhomework
2021-01-05 11:02         ` raid5atemyhomework
2021-01-05 14:56           ` raid5atemyhomework
2021-01-06  0:59             ` Carlo Zancanaro
2021-01-06  3:50               ` raid5atemyhomework
2021-01-06  3:58                 ` Carlo Zancanaro
     [not found]                   ` <t=5Ft9LHglTTJw2Bhtd2xX4JCJeZBi5Drqg0t04vJsfRLfoENqpftZcuHO8LYi2AO05P71lbbCgQC5etCDiPsdcssJmw1pHGyCY3 gUT-9w9?= =?us-ascii?Q?=5Fo=3D@protonmail.com>
     [not found]                     ` <Zd8uMcxWfNY1RxDn4gwrCZjHKAUxSQgcuBsNDAqa0tMqj=5FufQWE-URr7L49OBWMGDfQB8v=5F8eRdnhlsZTxU0Xq=5FF6tu-92jvvc1lSh-2tdA=3D@protonmail.com>
     [not found]                       ` <vzCMYS=5FrSzkd3ZDA5TktzybU2LmfZsjWLmrd0ABQ1bIKyulAreAghoDBo0yjb-bEbH5ZmKhOO3D9WPjuDoMMUs0O eUWA1WakV?= =?us-ascii?Q?WFo6H61IHY=3D@protonmail.com>
     [not found]                         ` <07kwAFNpjhGFe7ArkjjAtRhr564wvMPGhHFyjGb=5FXdmmPNddKTmT9Swky1NbbUxHBC4xw3p-m=5F3JyW16Ql9J7PLyk6UdhCsA2cdkHehdti8=3D@protonmail.com>
     [not found]                           ` <VnQXBr-z8pdZxWrb6VtIu5pv0UeG1II5uUu4Q7BU3NsJMQbxhiQyWJE4fhEIWJO3VWrjetf1SMIu4=5Fgi5r2AlY q8dADCXCD?= =?us-ascii?Q?wW30RYaJ6seA=3D@protonmail.com>
     [not found]                             ` <BwsjjkFjW7wwYSYYp-YUhl5t1-1OtA8t3wbDftsQTZBXHNxcR2tBprzJmBYvNrMKnCeiu0d5bPz7V8IaKIdYu9NP7kDsd16z6gMPpR89-3c=3D@protonmail.com>
     [not found]                           ` <VnQXBr-z8pdZxWrb6VtIu5pv0UeG1II5uUu4Q7BU3NsJMQbxhiQyWJE4fhEIWJO3VWrjetf1SMIu4=5Fgi5r2AlYq8dADCXCDwW30RYaJ6seA=3D@protonmail.com>
     [not found]                             ` <BwsjjkFjW7wwYSYYp-YUhl5t1-1OtA8t3wbDftsQTZBXHNxcR2tBprzJmBYvNrMKnCeiu0d5bPz7V8IaKIdYu9NP7kDsd16z6gMPpR89-3c=3D@protonmail.c om>
2021-01-06  4:41                   ` raid5atemyhomework
2021-01-06  5:20                     ` raid5atemyhomework [this message]
2021-01-06 15:58                       ` raid5atemyhomework
2021-01-09 18:14                         ` raid5atemyhomework
2021-01-10  5:17                           ` raid5atemyhomework
2021-02-08  2:13                             ` raid5atemyhomework
2021-02-08  3:51                               ` Joshua Branson
2021-02-08  6:04                                 ` raid5atemyhomework
2021-02-08  6:13                               ` raid5atemyhomework
2021-02-08  9:17                               ` Maxime Devos
2021-02-08  9:32                                 ` raid5atemyhomework
2021-02-08  9:35                                   ` Maxime Devos
2021-02-10  8:29                                   ` Efraim Flashner
2021-02-08  2:16                 ` Danny Milosavljevic
2021-02-10  7:37                   ` raid5atemyhomework
     [not found] <=5F1CLe9QSGsoMlu5WxBMXm4CbFLM=5FM9iRG1XQF9GDsK0GP208jpngdymfix4tAfoLP94mhMTt-Tx6OP2xN=5Fn78Jhx5KQzkiqPpIci=5F44C9OI=3D@protonmail.com>

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