diff options
Diffstat (limited to 'gnu/system/file-systems.scm')
| -rw-r--r-- | gnu/system/file-systems.scm | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/gnu/system/file-systems.scm b/gnu/system/file-systems.scm index b41f66e943..0f94577760 100644 --- a/gnu/system/file-systems.scm +++ b/gnu/system/file-systems.scm @@ -1,6 +1,7 @@ ;;; GNU Guix --- Functional package management for GNU ;;; Copyright © 2013, 2014, 2015, 2016, 2017, 2018, 2019 Ludovic Courtès <ludo@gnu.org> ;;; Copyright © 2020 Jakub Kądziołka <kuba@kadziolka.net> +;;; Copyright © 2020 Maxim Cournoyer <maxim.cournoyer@gmail.com> ;;; ;;; This file is part of GNU Guix. ;;; @@ -21,7 +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) @@ -38,6 +42,9 @@ file-system-needed-for-boot? file-system-flags file-system-options + file-system-options->alist + alist->file-system-options + file-system-mount? file-system-check? file-system-create-mount-point? @@ -45,6 +52,8 @@ file-system-location file-system-type-predicate + btrfs-subvolume? + btrfs-store-subvolume-file-name file-system-label file-system-label? @@ -251,6 +260,33 @@ UUID-TYPE, a symbol such as 'dce or 'iso9660." ((? string?) device))) +(define (file-system-options->alist string) + "Translate the option string format of a <file-system> record into an +association list of options or option/value pairs." + (if string + (let ((options (string-split string #\,))) + (map (lambda (param) + (let ((=index (string-index param #\=))) + (if =index + (cons (string-take param =index) + (string-drop param (1+ =index))) + param))) + options)) + '())) + +(define (alist->file-system-options options) + "Return the string representation of OPTIONS, an association list. The +string obtained can be used as the option field of a <file-system> record." + (if (null? options) + #f + (string-join (map (match-lambda + ((key . value) + (string-append key "=" value)) + (key + key)) + options) + ","))) + (define (file-system-needed-for-boot? fs) "Return true if FS has the 'needed-for-boot?' flag set, or if it holds the store--e.g., if FS is the root file system." @@ -535,4 +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 |