bug#25917: [PATCH] file-systems: Factorize file-system-packages.

[Danny Milosavljevic <dannym@scratchpost.org>]

* gnu/system/linux-initrd.scm (base-initrd): Move helper-packages body to ...
* gnu/system/file-systems.scm (file-system-packages): ... here.
Also export it.
* gnu/services/base.scm (file-system-shepherd-service): Set PATH by using
file-system-packages.
---
 gnu/services/base.scm       | 12 ++++++------
 gnu/system/file-systems.scm | 26 ++++++++++++++++++++++++++
 gnu/system/linux-initrd.scm | 18 +-----------------
 3 files changed, 33 insertions(+), 23 deletions(-)

diff --git a/gnu/services/base.scm b/gnu/services/base.scm
index 5298a11f6..f3224aae1 100644
--- a/gnu/services/base.scm
+++ b/gnu/services/base.scm
@@ -274,7 +274,9 @@ FILE-SYSTEM."
         (options (file-system-options file-system))
         (check?  (file-system-check? file-system))
         (create? (file-system-create-mount-point? file-system))
-        (dependencies (file-system-dependencies file-system)))
+        (needed-for-boot? (file-system-needed-for-boot? file-system))
+        (dependencies (file-system-dependencies file-system))
+        (packages (file-system-packages (list file-system))))
     (and (file-system-mount? file-system)
          (with-imported-modules '((gnu build file-systems)
                                   (guix build bournish))
@@ -292,11 +294,9 @@ FILE-SYSTEM."
                          ;; Make sure fsck.ext2 & co. can be found.
                          (dynamic-wind
                            (lambda ()
-                             (setenv "PATH"
-                                     (string-append
-                                      #$e2fsprogs "/sbin:"
-                                      "/run/current-system/profile/sbin:"
-                                      $PATH)))
+                             (set-path-environment-variable "PATH"
+                                                            '("bin" "sbin")
+                                                            '#$packages))
                            (lambda ()
                              (mount-file-system
                               `(#$device #$title #$target #$type #$flags
diff --git a/gnu/system/file-systems.scm b/gnu/system/file-systems.scm
index 7011a279d..8107722c7 100644
--- a/gnu/system/file-systems.scm
+++ b/gnu/system/file-systems.scm
@@ -22,6 +22,8 @@
   #:use-module (guix records)
   #:use-module ((gnu build file-systems)
                 #:select (string->uuid uuid->string))
+  #:use-module (gnu packages linux)
+  #:use-module (gnu packages disk)
   #:re-export (string->uuid
                uuid->string)
   #:export (<file-system>
@@ -65,6 +67,8 @@
 
             file-system-mapping->bind-mount
 
+            file-system-packages
+
             %store-mapping
             %network-configuration-files
             %network-file-mappings))
@@ -411,4 +415,26 @@ a bind mount."
                  (writable? (string=? file "/etc/resolv.conf"))))
               %network-configuration-files))
 
+(define (file-system-type-predicate type)
+  (lambda (fs)
+    (string=? (file-system-type fs) type)))
+
+(define* (file-system-packages file-systems #:key (volatile-root? #f))
+ `(,@(if (find (lambda (fs)
+                 (string-prefix? "ext" (file-system-type fs)))
+               file-systems)
+         (list e2fsck/static)
+         '())
+   ,@(if (find (lambda (fs)
+                 (string-suffix? "fat" (file-system-type fs)))
+               file-systems)
+         (list fatfsck/static)
+         '())
+   ,@(if (find (file-system-type-predicate "btrfs") file-systems)
+         (list btrfs-progs/static)
+         '())
+   ,@(if volatile-root?
+         (list unionfs-fuse/static)
+         '())))
+
 ;;; file-systems.scm ends here
diff --git a/gnu/system/linux-initrd.scm b/gnu/system/linux-initrd.scm
index 81c1278c0..1f1c30682 100644
--- a/gnu/system/linux-initrd.scm
+++ b/gnu/system/linux-initrd.scm
@@ -272,23 +272,7 @@ loaded at boot time in the order in which they appear."
       ,@extra-modules))
 
   (define helper-packages
-    ;; Packages to be copied on the initrd.
-    `(,@(if (find (lambda (fs)
-                    (string-prefix? "ext" (file-system-type fs)))
-                  file-systems)
-            (list e2fsck/static)
-            '())
-      ,@(if (find (lambda (fs)
-                    (string-suffix? "fat" (file-system-type fs)))
-                  file-systems)
-            (list fatfsck/static)
-            '())
-      ,@(if (find (file-system-type-predicate "btrfs") file-systems)
-            (list btrfs-progs/static)
-            '())
-      ,@(if volatile-root?
-            (list unionfs-fuse/static)
-            '())))
+    (file-system-packages file-systems #:volatile-root? volatile-root?))
 
   (raw-initrd file-systems
               #:linux linux