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>
This commit is contained in:
Richard Sent 2024-06-01 19:26:16 -04:00 committed by Ludovic Courtès
parent 5d3edff1a6
commit 579df5bc80
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3 changed files with 56 additions and 29 deletions

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

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@ -404,6 +404,7 @@ (define (file-system-shepherd-service file-system)
(create? (file-system-create-mount-point? file-system)) (create? (file-system-create-mount-point? file-system))
(mount? (file-system-mount? file-system)) (mount? (file-system-mount? file-system))
(dependencies (file-system-dependencies file-system)) (dependencies (file-system-dependencies file-system))
(requirements (file-system-shepherd-requirements file-system))
(packages (file-system-packages (list file-system)))) (packages (file-system-packages (list file-system))))
(and (or mount? create?) (and (or mount? create?)
(with-imported-modules (source-module-closure (with-imported-modules (source-module-closure
@ -412,7 +413,8 @@ (define (file-system-shepherd-service file-system)
(provision (list (file-system->shepherd-service-name file-system))) (provision (list (file-system->shepherd-service-name file-system)))
(requirement `(root-file-system (requirement `(root-file-system
udev udev
,@(map dependency->shepherd-service-name dependencies))) ,@(map dependency->shepherd-service-name dependencies)
,@requirements))
(documentation "Check, mount, and unmount the given file system.") (documentation "Check, mount, and unmount the given file system.")
(start #~(lambda args (start #~(lambda args
#$(if create? #$(if create?
@ -461,12 +463,20 @@ (define (file-system-shepherd-services file-systems)
(or (file-system-mount? x) (or (file-system-mount? x)
(file-system-create-mount-point? x))) (file-system-create-mount-point? x)))
file-systems))) file-systems)))
(define sink (define sink
(shepherd-service (shepherd-service
(provision '(file-systems)) (provision '(file-systems))
(requirement (cons* 'root-file-system 'user-file-systems (requirement (cons* 'root-file-system 'user-file-systems
(map file-system->shepherd-service-name (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") (documentation "Target for all the initially-mounted file systems")
(start #~(const #t)) (start #~(const #t))
(stop #~(const #f)))) (stop #~(const #f))))

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@ -57,6 +57,7 @@ (define-module (gnu system file-systems)
file-system-repair file-system-repair
file-system-create-mount-point? file-system-create-mount-point?
file-system-dependencies file-system-dependencies
file-system-shepherd-requirements
file-system-location file-system-location
file-system-type-predicate file-system-type-predicate
@ -161,33 +162,35 @@ (define-syntax validate-file-system-flags
(define-record-type* <file-system> file-system (define-record-type* <file-system> file-system
make-file-system make-file-system
file-system? file-system?
(device file-system-device) ; string | <uuid> | <file-system-label> (device file-system-device) ; string | <uuid> | <file-system-label>
(mount-point file-system-mount-point) ; string (mount-point file-system-mount-point) ; string
(type file-system-type) ; string (type file-system-type) ; string
(flags file-system-flags ; list of symbols (flags file-system-flags ; list of symbols
(default '()) (default '())
(sanitize validate-file-system-flags)) (sanitize validate-file-system-flags))
(options file-system-options ; string or #f (options file-system-options ; string or #f
(default #f)) (default #f))
(mount? file-system-mount? ; Boolean (mount? file-system-mount? ; Boolean
(default #t)) (default #t))
(mount-may-fail? file-system-mount-may-fail? ; Boolean (mount-may-fail? file-system-mount-may-fail? ; Boolean
(default #f)) (default #f))
(needed-for-boot? %file-system-needed-for-boot? ; Boolean (needed-for-boot? %file-system-needed-for-boot? ; Boolean
(default #f)) (default #f))
(check? file-system-check? ; Boolean (check? file-system-check? ; Boolean
(default #t)) (default #t))
(skip-check-if-clean? file-system-skip-check-if-clean? ; Boolean (skip-check-if-clean? file-system-skip-check-if-clean? ; Boolean
(default #t)) (default #t))
(repair file-system-repair ; symbol or #f (repair file-system-repair ; symbol or #f
(default 'preen)) (default 'preen))
(create-mount-point? file-system-create-mount-point? ; Boolean (create-mount-point? file-system-create-mount-point? ; Boolean
(default #f)) (default #f))
(dependencies file-system-dependencies ; list of <file-system> (dependencies file-system-dependencies ; list of <file-system>
(default '())) ; or <mapped-device> (default '())) ; or <mapped-device>
(location file-system-location (shepherd-requirements file-system-shepherd-requirements ; list of symbols
(default (current-source-location)) (default '()))
(innate))) (location file-system-location
(default (current-source-location))
(innate)))
;; A file system label for use in the 'device' field. ;; A file system label for use in the 'device' field.
(define-record-type <file-system-label> (define-record-type <file-system-label>