system: Add (gnu system mapped-devices).

* gnu/system/file-systems.scm (<mapped-device>, <mapped-device-type>):
Move to...
* gnu/system/mapped-devices.scm: ... here.  New file.
* gnu/system.scm, gnu/services/base.scm,
gnu/system/linux-initrd.scm: Use it.
* gnu-system.am (GNU_SYSTEM_MODULES): Add it.
* gnu.scm (%public-modules): Add it.

gnu-system.am

@@ -383,6 +383,7 @@ GNU_SYSTEM_MODULES =				\
   gnu/system/linux-container.scm		\
   gnu/system/linux-initrd.scm			\
   gnu/system/locale.scm				\
+  gnu/system/mapped-devices.scm			\
   gnu/system/nss.scm				\
   gnu/system/pam.scm				\
   gnu/system/shadow.scm				\

gnu.scm

@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2014, 2015 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2014, 2015, 2016 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright © 2015 Joshua S. Grant <jgrant@parenthetical.io>
 ;;;
 ;;; This file is part of GNU Guix.
@@ -32,6 +32,7 @@
   (begin
     (define %public-modules
       '((gnu system)
+        (gnu system mapped-devices)
         (gnu system file-systems)
         (gnu system grub)                         ; 'grub-configuration'
         (gnu system pam)

gnu/services/base.scm

@@ -27,6 +27,7 @@
   #:use-module (gnu system pam)
   #:use-module (gnu system shadow)                ; 'user-account', etc.
   #:use-module (gnu system file-systems)          ; 'file-system', etc.
+  #:use-module (gnu system mapped-devices)
   #:use-module (gnu packages admin)
   #:use-module ((gnu packages linux)
                 #:select (eudev kbd e2fsprogs lvm2 fuse alsa-utils crda gpm))

gnu/system.scm

@@ -54,6 +54,7 @@
   #:use-module (gnu system pam)
   #:use-module (gnu system linux-initrd)
   #:use-module (gnu system file-systems)
+  #:use-module (gnu system mapped-devices)
   #:use-module (ice-9 match)
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-26)

gnu/system/file-systems.scm

@@ -54,17 +54,6 @@
             %base-file-systems
             %container-file-systems
 
-            mapped-device
-            mapped-device?
-            mapped-device-source
-            mapped-device-target
-            mapped-device-type
-
-            mapped-device-kind
-            mapped-device-kind?
-            mapped-device-kind-open
-            mapped-device-kind-close
-
             <file-system-mapping>
             file-system-mapping
             file-system-mapping?
@@ -293,26 +282,6 @@ initrd code."
      (create-mount-point? #t)
      (check? #f))))
 
-
-
-;;;
-;;; Mapped devices, for Linux's device-mapper.
-;;;
-
-(define-record-type* <mapped-device> mapped-device
-  make-mapped-device
-  mapped-device?
-  (source    mapped-device-source)                ;string
-  (target    mapped-device-target)                ;string
-  (type      mapped-device-type))                 ;<mapped-device-kind>
-
-(define-record-type* <mapped-device-type> mapped-device-kind
-  make-mapped-device-kind
-  mapped-device-kind?
-  (open      mapped-device-kind-open)             ;source target -> gexp
-  (close     mapped-device-kind-close             ;source target -> gexp
-             (default (const #~(const #f)))))
-
 
 ;;;
 ;;; Shared file systems, for VMs/containers.

gnu/system/linux-initrd.scm

@@ -32,6 +32,7 @@
   #:use-module ((gnu packages make-bootstrap)
                 #:select (%guile-static-stripped))
   #:use-module (gnu system file-systems)
+  #:use-module (gnu system mapped-devices)
   #:use-module (ice-9 match)
   #:use-module (ice-9 regex)
   #:use-module (srfi srfi-1)

gnu/system/mapped-devices.scm

@@ -0,0 +1,53 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2014, 2015, 2016 Ludovic Courtès <ludo@gnu.org>
+;;;
+;;; 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 system mapped-devices)
+  #:use-module (guix records)
+  #:export (mapped-device
+            mapped-device?
+            mapped-device-source
+            mapped-device-target
+            mapped-device-type
+
+            mapped-device-kind
+            mapped-device-kind?
+            mapped-device-kind-open
+            mapped-device-kind-close))
+
+;;; Commentary:
+;;;
+;;; This module supports "device mapping", a concept implemented by Linux's
+;;; device-mapper.
+;;;
+;;; Code:
+
+(define-record-type* <mapped-device> mapped-device
+  make-mapped-device
+  mapped-device?
+  (source    mapped-device-source)                ;string
+  (target    mapped-device-target)                ;string
+  (type      mapped-device-type))                 ;<mapped-device-kind>
+
+(define-record-type* <mapped-device-type> mapped-device-kind
+  make-mapped-device-kind
+  mapped-device-kind?
+  (open      mapped-device-kind-open)             ;source target -> gexp
+  (close     mapped-device-kind-close             ;source target -> gexp
+             (default (const #~(const #f)))))
+
+;;; mapped-devices.scm ends here