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authorMaxim Cournoyer <maxim.cournoyer@gmail.com>2019-07-14 20:50:23 +0900
committerMaxim Cournoyer <maxim.cournoyer@gmail.com>2020-05-20 08:30:35 -0400
commitb460ba7992a0b4af2ddb5927dcf062784539ef7b (patch)
tree4d77d01574da9a7aedf31dc3f16e94d82fa31adb /gnu/system/file-systems.scm
parentfa35fb58c84d1c1741e4e63c0b37074e35ed2a61 (diff)
bootloader: grub: Allow booting from a Btrfs subvolume.
* gnu/bootloader/grub.scm (strip-mount-point): Remove procedure. (normalize-file): Add procedure. (grub-configuration-file): New BTRFS-SUBVOLUME-FILE-NAME parameter. When defined, prepend its value to the kernel and initrd file names, using the NORMALIZE-FILE procedure. Adjust the call to EYE-CANDY to pass the BTRFS-SUBVOLUME-FILE-NAME argument. Normalize the KEYMAP file as well. (eye-candy): Add a BTRFS-SUBVOLUME-FILE-NAME parameter, and use it, along with the NORMALIZE-FILE procedure, to normalize the FONT-FILE and IMAGE nested variables. Adjust doc. * gnu/bootloader/depthcharge.scm (depthcharge-configuration-file): Adapt. * gnu/bootloader/extlinux.scm (extlinux-configuration-file): Likewise. * gnu/system/file-systems.scm (btrfs-subvolume?) (btrfs-store-subvolume-file-name): New procedures. * gnu/system.scm (operating-system-bootcfg): Specify the Btrfs subvolume file name the store resides on to the `operating-system-bootcfg' procedure, using the new BTRFS-SUBVOLUME-FILE-NAME argument. * doc/guix.texi (File Systems): Add a Btrfs subsection to document the use of subvolumes. * gnu/tests/install.scm (%btrfs-root-on-subvolume-os) (%btrfs-root-on-subvolume-os-source) (%btrfs-root-on-subvolume-installation-script) (%test-btrfs-root-on-subvolume-os): New variables.
Diffstat (limited to 'gnu/system/file-systems.scm')
-rw-r--r--gnu/system/file-systems.scm55
1 files changed, 55 insertions, 0 deletions
diff --git a/gnu/system/file-systems.scm b/gnu/system/file-systems.scm
index 07f272db7c..0f94577760 100644
--- a/gnu/system/file-systems.scm
+++ b/gnu/system/file-systems.scm
@@ -22,7 +22,10 @@
#:use-module (ice-9 match)
#:use-module (rnrs bytevectors)
#:use-module (srfi srfi-1)
+ #:use-module (srfi srfi-2)
#:use-module (srfi srfi-9)
+ #:use-module (srfi srfi-26)
+ #:use-module (srfi srfi-35)
#:use-module (srfi srfi-9 gnu)
#:use-module (guix records)
#:use-module (gnu system uuid)
@@ -49,6 +52,8 @@
file-system-location
file-system-type-predicate
+ btrfs-subvolume?
+ btrfs-store-subvolume-file-name
file-system-label
file-system-label?
@@ -566,4 +571,54 @@ system has the given TYPE."
(lambda (fs)
(string=? (file-system-type fs) type)))
+
+;;;
+;;; Btrfs specific helpers.
+;;;
+
+(define (btrfs-subvolume? fs)
+ "Predicate to check if FS, a file-system object, is a Btrfs subvolume."
+ (and-let* ((btrfs-file-system? (string= "btrfs" (file-system-type fs)))
+ (option-keys (map (match-lambda
+ ((key . value) key)
+ (key key))
+ (file-system-options->alist
+ (file-system-options fs)))))
+ (find (cut string-prefix? "subvol" <>) option-keys)))
+
+(define (btrfs-store-subvolume-file-name file-systems)
+ "Return the subvolume file name within the Btrfs top level onto which the
+store is located, else #f."
+
+ (define (prepend-slash/maybe s)
+ (if (string=? "/" (string-take s 1))
+ s
+ (string-append "/" s)))
+
+ (define (file-name-depth file-name)
+ (length (string-tokenize file-name %not-slash)))
+
+ (and-let* ((btrfs-subvolume-fs (filter btrfs-subvolume? file-systems))
+ (btrfs-subvolume-fs*
+ (sort btrfs-subvolume-fs
+ (lambda (fs1 fs2)
+ (> (file-name-depth (file-system-mount-point fs1))
+ (file-name-depth (file-system-mount-point fs2))))))
+ (store-subvolume-fs
+ (find (lambda (fs) (file-prefix? (file-system-mount-point fs)
+ (%store-prefix)))
+ btrfs-subvolume-fs*))
+ (options (file-system-options->alist
+ (file-system-options store-subvolume-fs))))
+ ;; XXX: Deriving the subvolume name based from a subvolume ID is not
+ ;; supported, as we'd need to query the actual file system.
+ (or (and=> (assoc-ref options "subvol") prepend-slash/maybe)
+ ;; FIXME: Use &fix-hint once it no longer pulls in (guix utils).
+ (raise (condition
+ (&message
+ (message "The store is on a Btrfs subvolume, but the \
+subvolume name is unknown.
+Hint: Use the \"subvol\" Btrfs file system option.")))))))
+
+
;;; file-systems.scm ends here