~ruther/guix-local

579df5bc80fbedc59dc1b99751dcc49deab8f488 — Richard Sent 1 year, 8 months ago 5d3edff
services: base: Add optional delayed mount of file-systems

Add a mechanism to only require mounting a subset of file-system entries
during early Shepherd initialization. Any file-system with additional Shepherd
service requirements (e.g. networking) is not required to provision
'file-systems.

* gnu/services/base.scm (file-system-shepherd-service): Splice
file-system-requirements into the Shepherd service requirement list.
(file-system-shepherd-services): Provision 'file-system only when file system
services without additional Shepherd requirements are started.
* gnu/system/file-systems.scm (file-system): Add shepherd-requirements field
to the file-system record. This field is used for adding additional Shepherd
requirements to a file-system Shepherd service.
* doc/guix.texi: Add documentation for file-system shepherd-requirements.

Change-Id: If0392db03d48e8820aa53df1df482c12ec72e1a5
Signed-off-by: Ludovic Courtès <ludo@gnu.org>
3 files changed, 56 insertions(+), 29 deletions(-)

M doc/guix.texi
M gnu/services/base.scm
M gnu/system/file-systems.scm
M doc/guix.texi => doc/guix.texi +14 -0
@@ 17862,6 17862,20 @@ a dependency of @file{/sys/fs/cgroup/cpu} and

Another example is a file system that depends on a mapped device, for
example for an encrypted partition (@pxref{Mapped Devices}).

@item @code{shepherd-requirements} (default: @code{'()})
This is a list of symbols denoting Shepherd requirements that must be
met before mounting the file system.

As an example, an NFS file system would typically have a requirement for
@code{networking}.

Typically, file systems are mounted before most other Shepherd services
are started.  However, file systems with a non-empty
shepherd-requirements field are mounted after Shepherd services have
begun.  Any Shepherd service that depends on a file system with a
non-empty shepherd-requirements field must depend on it directly and not
on the generic symbol @code{file-systems}.
@end table
@end deftp


M gnu/services/base.scm => gnu/services/base.scm +12 -2
@@ 404,6 404,7 @@ upon boot."
        (create? (file-system-create-mount-point? file-system))
        (mount?  (file-system-mount? file-system))
        (dependencies (file-system-dependencies file-system))
        (requirements (file-system-shepherd-requirements file-system))
        (packages (file-system-packages (list file-system))))
    (and (or mount? create?)
         (with-imported-modules (source-module-closure


@@ 412,7 413,8 @@ upon boot."
            (provision (list (file-system->shepherd-service-name file-system)))
            (requirement `(root-file-system
                           udev
                           ,@(map dependency->shepherd-service-name dependencies)))
                           ,@(map dependency->shepherd-service-name dependencies)
                           ,@requirements))
            (documentation "Check, mount, and unmount the given file system.")
            (start #~(lambda args
                       #$(if create?


@@ 461,12 463,20 @@ upon boot."
                                 (or (file-system-mount? x)
                                     (file-system-create-mount-point? x)))
                               file-systems)))

    (define sink
      (shepherd-service
       (provision '(file-systems))
       (requirement (cons* 'root-file-system 'user-file-systems
                           (map file-system->shepherd-service-name
                                file-systems)))
                                ;; Do not require file systems with Shepherd
                                ;; requirements to provision
                                ;; 'file-systems. Many Shepherd services
                                ;; require 'file-systems, so we would likely
                                ;; deadlock.
                                (filter (lambda (file-system)
                                          (null? (file-system-shepherd-requirements file-system)))
                                        file-systems))))
       (documentation "Target for all the initially-mounted file systems")
       (start #~(const #t))
       (stop #~(const #f))))

M gnu/system/file-systems.scm => gnu/system/file-systems.scm +30 -27
@@ 57,6 57,7 @@
            file-system-repair
            file-system-create-mount-point?
            file-system-dependencies
            file-system-shepherd-requirements
            file-system-location

            file-system-type-predicate


@@ 161,33 162,35 @@ flags are found."
(define-record-type* <file-system> file-system
  make-file-system
  file-system?
  (device           file-system-device) ; string | <uuid> | <file-system-label>
  (mount-point      file-system-mount-point)      ; string
  (type             file-system-type)             ; string
  (flags            file-system-flags             ; list of symbols
                    (default '())
                    (sanitize validate-file-system-flags))
  (options          file-system-options           ; string or #f
                    (default #f))
  (mount?           file-system-mount?            ; Boolean
                    (default #t))
  (mount-may-fail?  file-system-mount-may-fail?   ; Boolean
                    (default #f))
  (needed-for-boot? %file-system-needed-for-boot? ; Boolean
                    (default #f))
  (check?           file-system-check?            ; Boolean
                    (default #t))
  (skip-check-if-clean? file-system-skip-check-if-clean? ; Boolean
                        (default #t))
  (repair           file-system-repair            ; symbol or #f
                    (default 'preen))
  (create-mount-point? file-system-create-mount-point? ; Boolean
                       (default #f))
  (dependencies     file-system-dependencies      ; list of <file-system>
                    (default '()))                ; or <mapped-device>
  (location         file-system-location
                    (default (current-source-location))
                    (innate)))
  (device                file-system-device)               ; string | <uuid> | <file-system-label>
  (mount-point           file-system-mount-point)          ; string
  (type                  file-system-type)                 ; string
  (flags                 file-system-flags                 ; list of symbols
                         (default '())
                         (sanitize validate-file-system-flags))
  (options               file-system-options               ; string or #f
                         (default #f))
  (mount?                file-system-mount?                ; Boolean
                         (default #t))
  (mount-may-fail?       file-system-mount-may-fail?       ; Boolean
                         (default #f))
  (needed-for-boot?      %file-system-needed-for-boot?     ; Boolean
                         (default #f))
  (check?                file-system-check?                ; Boolean
                         (default #t))
  (skip-check-if-clean?  file-system-skip-check-if-clean?  ; Boolean
                         (default #t))
  (repair                file-system-repair                ; symbol or #f
                         (default 'preen))
  (create-mount-point?   file-system-create-mount-point?   ; Boolean
                         (default #f))
  (dependencies          file-system-dependencies          ; list of <file-system>
                         (default '()))                    ; or <mapped-device>
  (shepherd-requirements file-system-shepherd-requirements ; list of symbols
                         (default '()))
  (location              file-system-location
                         (default (current-source-location))
                         (innate)))

;; A file system label for use in the 'device' field.
(define-record-type <file-system-label>