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authorLudovic Courtès <ludo@gnu.org>2014-09-22 11:06:42 +0200
committerLudovic Courtès <ludo@gnu.org>2014-09-22 11:20:41 +0200
commitde1c158f32e1d4060daa600a62b68fe22b613424 (patch)
tree5b1d35a3d17a2d5bb0083ce7ee8edd45132dd2e9
parente2b464b7f444743aed5ffc6d9191749c21a0d159 (diff)
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.
-rw-r--r--gnu/build/linux-boot.scm12
-rw-r--r--gnu/system.scm42
-rw-r--r--gnu/system/linux-initrd.scm16
3 files changed, 61 insertions, 9 deletions
diff --git a/gnu/build/linux-boot.scm b/gnu/build/linux-boot.scm
index 56042da8f6..a58232c815 100644
--- a/gnu/build/linux-boot.scm
+++ b/gnu/build/linux-boot.scm
@@ -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))
diff --git a/gnu/system.scm b/gnu/system.scm
index 13b461c003..d15c864384 100644
--- a/gnu/system.scm
+++ b/gnu/system.scm
@@ -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 #$initrd "/initrd"))))
(define (kernel->grub-label kernel)
diff --git a/gnu/system/linux-initrd.scm b/gnu/system/linux-initrd.scm
index cb04644053..d1b1216f9d 100644
--- a/gnu/system/linux-initrd.scm
+++ b/gnu/system/linux-initrd.scm
@@ -126,14 +126,16 @@ initrd code."
(define* (base-initrd file-systems
#:key
+ (mapped-devices '())
qemu-networking?
virtio?
volatile-root?
(extra-modules '()))
- ;; TODO: Support boot-time device mappings.
"Return a monadic derivation that builds a generic initrd. FILE-SYSTEMS is
a list of file-systems to be mounted by the initrd, possibly in addition to
the root file system specified on the kernel command line via '--root'.
+MAPPED-DEVICES is a list of device mappings to realize before FILE-SYSTEMS are
+mounted.
When QEMU-NETWORKING? is true, set up networking with the standard QEMU
parameters. When VIRTIO? is true, load additional modules so the initrd can
@@ -191,6 +193,16 @@ loaded at boot time in the order in which they appear."
(list unionfs-fuse/static)
'())))
+ (define device-mapping-commands
+ ;; List of gexps to open the mapped devices.
+ (map (lambda (md)
+ (let* ((source (mapped-device-source md))
+ (target (mapped-device-target md))
+ (type (mapped-device-type md))
+ (open (mapped-device-kind-open type)))
+ (open source target)))
+ mapped-devices))
+
(mlet %store-monad ((kodir (flat-linux-module-directory linux-libre
linux-modules)))
(expression->initrd
@@ -205,6 +217,8 @@ loaded at boot time in the order in which they appear."
'#$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)