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.

1 files changed, 53 insertions, 0 deletions

diff --git a/gnu/system/mapped-devices.scm b/gnu/system/mapped-devices.scm
new file mode 100644
index 0000000000..81afb91f86
--- /dev/null
+++ b/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