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system: Add support for boot-time mapped devices.

* gnu/build/linux-boot.scm (boot-system): Add #:pre-mount parameter and
  honor it.
* gnu/system/linux-initrd.scm (base-initrd): Add #:mapped-devices
  parameter.  Add 'device-mapping-commands' variable, and use it to
  build the #:pre-mount argument of 'boot-system'.
* gnu/system.scm (mapped-device-user,
  operating-system-user-mapped-devices,
  operating-system-boot-mapped-devices): New procedures.
  (device-mapping-services): Use 'operating-system-user-mapped-devices'
  instead of 'operating-system-mapped-devices'.
  (operating-system-initrd-file): Call the initrd with #:mapped-devices.
gn-latest-20200428
Ludovic Courtès 7 years ago
parent
commit
de1c158f32
3 changed files with 61 additions and 9 deletions
  1. +9
    -3
      gnu/build/linux-boot.scm
  2. +37
    -5
      gnu/system.scm
  3. +15
    -1
      gnu/system/linux-initrd.scm

+ 9
- 3
gnu/build/linux-boot.scm View File

@ -340,13 +340,14 @@ bailing out.~%root contents: ~s~%" (scandir "/"))
(linux-modules '())
qemu-guest-networking?
volatile-root?
pre-mount
(mounts '()))
"This procedure is meant to be called from an initrd. Boot a system by
first loading LINUX-MODULES (a list of absolute file names of '.ko' files),
then setting up QEMU guest networking if QEMU-GUEST-NETWORKING? is true,
mounting the file systems specified in MOUNTS, and finally booting into the
new root if any. The initrd supports kernel command-line options '--load',
'--root', and '--repl'.
calling PRE-MOUNT, mounting the file systems specified in MOUNTS, and finally
booting into the new root if any. The initrd supports kernel command-line
options '--load', '--root', and '--repl'.
Mount the root file system, specified by the '--root' command-line argument,
if any.
@ -403,6 +404,11 @@ to it are lost."
(mkdir "/root/dev")
(make-essential-device-nodes #:root "/root"))
(when (procedure? pre-mount)
;; Do whatever actions are needed before mounting--e.g., installing
;; device mappings.
(pre-mount))
;; Mount the specified file systems.
(for-each mount-file-system
(remove root-mount-point? mounts))


+ 37
- 5
gnu/system.scm View File

@ -216,6 +216,34 @@ as 'needed-for-boot'."
#:flags flags))))
file-systems)))
(define (mapped-device-user device file-systems)
"Return a file system among FILE-SYSTEMS that uses DEVICE, or #f."
(let ((target (string-append "/dev/mapper/" (mapped-device-target device))))
(find (lambda (fs)
(string=? (file-system-device fs) target))
file-systems)))
(define (operating-system-user-mapped-devices os)
"Return the subset of mapped devices that can be installed in
user-land--i.e., those not needed during boot."
(let ((devices (operating-system-mapped-devices os))
(file-systems (operating-system-file-systems os)))
(filter (lambda (md)
(let ((user (mapped-device-user md file-systems)))
(or (not user)
(not (file-system-needed-for-boot? user)))))
devices)))
(define (operating-system-boot-mapped-devices os)
"Return the subset of mapped devices that must be installed during boot,
from the initrd."
(let ((devices (operating-system-mapped-devices os))
(file-systems (operating-system-file-systems os)))
(filter (lambda (md)
(let ((user (mapped-device-user md file-systems)))
(and user (file-system-needed-for-boot? user))))
devices)))
(define (device-mapping-services os)
"Return the list of device-mapping services for OS as a monadic list."
(sequence %store-monad
@ -228,7 +256,7 @@ as 'needed-for-boot'."
(device-mapping-service target
(open source target)
(close source target))))
(operating-system-mapped-devices os))))
(operating-system-user-mapped-devices os))))
(define (swap-services os)
"Return the list of swap services for OS as a monadic list."
@ -561,10 +589,14 @@ we're running in the final root."
boot?))
(operating-system-file-systems os)))
;; TODO: Pass the mapped devices required by boot-time file systems to the
;; initrd.
(mlet %store-monad
((initrd ((operating-system-initrd os) boot-file-systems)))
(define mapped-devices
(operating-system-boot-mapped-devices os))
(define make-initrd
(operating-system-initrd os))
(mlet %store-monad ((initrd (make-initrd boot-file-systems
#:mapped-devices mapped-devices)))
(return #~(string-append #$initrd "/initrd"))))
(define (kernel->grub-label kernel)


+ 15
- 1
gnu/system/linux-initrd.scm View File

@ -126,14 +126,16 @@ initrd code."
(define* (base-initrd file-systems
#:key
(mapped-devices '())
qemu-networking?
virtio?
volatile-root?
(extra-modules '()))
;; TODO: Support boot-time device mappings.
"Return a monadic derivation that builds a generic initrd. FILE-SYSTEMS is
a list of file-systems to be mounted by the initrd, possibly in addition to
the root file system specified on the kernel command line via '--root'.
MAPPED-DEVICES is a list of device mappings to realize before FILE-SYSTEMS are
mounted.
When QEMU-NETWORKING? is true, set up networking with the standard QEMU
parameters. When VIRTIO? is true, load additional modules so the initrd can
@ -191,6 +193,16 @@ loaded at boot time in the order in which they appear."
(list unionfs-fuse/static)
'())))
(define device-mapping-commands
;; List of gexps to open the mapped devices.
(map (lambda (md)
(let* ((source (mapped-device-source md))
(target (mapped-device-target md))
(type (mapped-device-type md))
(open (mapped-device-kind-open type)))
(open source target)))
mapped-devices))
(mlet %store-monad ((kodir (flat-linux-module-directory linux-libre
linux-modules)))
(expression->initrd
@ -205,6 +217,8 @@ loaded at boot time in the order in which they appear."
'#$helper-packages)))
(boot-system #:mounts '#$(map file-system->spec file-systems)
#:pre-mount (lambda ()
(and #$@device-mapping-commands))
#:linux-modules (map (lambda (file)
(string-append #$kodir "/" file))
'#$linux-modules)


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