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-rw-r--r--doc/guix.texi34
-rw-r--r--gnu/services/base.scm54
2 files changed, 71 insertions, 17 deletions
diff --git a/doc/guix.texi b/doc/guix.texi
index eddf77c7ab..2319bba2ba 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -13075,14 +13075,38 @@ A list of mapped devices. @xref{Mapped Devices}.
@item @code{file-systems}
A list of file systems. @xref{File Systems}.
-@item @code{swap-devices} (default: @code{'()})
@cindex swap devices
-A list of strings identifying devices or files to be used for ``swap
+@cindex swap space
+@item @code{swap-devices} (default: @code{'()})
+A list of UUIDs, file system labels, or strings identifying devices or
+files to be used for ``swap
space'' (@pxref{Memory Concepts,,, libc, The GNU C Library Reference
-Manual}). For example, @code{'("/dev/sda3")} or @code{'("/swapfile")}.
+Manual}). Here are some examples:
+
+@table @code
+@item (list (uuid "4dab5feb-d176-45de-b287-9b0a6e4c01cb"))
+Use the swap partition with the given UUID. You can learn the UUID of a
+Linux swap partition by running @command{swaplabel @var{device}}, where
+@var{device} is the @file{/dev} file name of that partition.
+
+@item (list (file-system-label "swap"))
+Use the partition with label @code{swap}. Again, the
+@command{swaplabel} command allows you to view and change the label of a
+Linux swap partition.
+
+@item (list "/swapfile")
+Use the file @file{/swapfile} as swap space.
+
+@item (list "/dev/sda3" "/dev/sdb2")
+Use the @file{/dev/sda3} and @file{/dev/sdb2} partitions as swap space.
+We recommend referring to swap devices by UUIDs or labels as shown above
+instead.
+@end table
+
It is possible to specify a swap file in a file system on a mapped
-device, provided that the necessary device mapping and file system are
-also specified. @xref{Mapped Devices} and @ref{File Systems}.
+device (under @file{/dev/mapper}), provided that the necessary device
+mapping and file system are also specified. @xref{Mapped Devices} and
+@ref{File Systems}.
@item @code{users} (default: @code{%base-user-accounts})
@itemx @code{groups} (default: @code{%base-groups})
diff --git a/gnu/services/base.scm b/gnu/services/base.scm
index 37b0a13ea7..07d9089b0a 100644
--- a/gnu/services/base.scm
+++ b/gnu/services/base.scm
@@ -2104,22 +2104,52 @@ instance."
'swap
(lambda (device)
(define requirement
- (if (string-prefix? "/dev/mapper/" device)
+ (if (and (string? device)
+ (string-prefix? "/dev/mapper/" device))
(list (symbol-append 'device-mapping-
(string->symbol (basename device))))
'()))
- (shepherd-service
- (provision (list (symbol-append 'swap- (string->symbol device))))
- (requirement `(udev ,@requirement))
- (documentation "Enable the given swap device.")
- (start #~(lambda ()
- (restart-on-EINTR (swapon #$device))
- #t))
- (stop #~(lambda _
- (restart-on-EINTR (swapoff #$device))
- #f))
- (respawn? #f)))))
+ (define (device-lookup device)
+ ;; The generic 'find-partition' procedures could return a partition
+ ;; that's not swap space, but that's unlikely.
+ (cond ((uuid? device)
+ #~(find-partition-by-uuid #$(uuid-bytevector device)))
+ ((file-system-label? device)
+ #~(find-partition-by-label
+ #$(file-system-label->string device)))
+ (else
+ device)))
+
+ (define service-name
+ (symbol-append 'swap-
+ (string->symbol
+ (cond ((uuid? device)
+ (string-take (uuid->string device) 6))
+ ((file-system-label? device)
+ (file-system-label->string device))
+ (else
+ device)))))
+
+ (with-imported-modules (source-module-closure '((gnu build file-systems)))
+ (shepherd-service
+ (provision (list service-name))
+ (requirement `(udev ,@requirement))
+ (documentation "Enable the given swap device.")
+ (modules `((gnu build file-systems)
+ ,@%default-modules))
+ (start #~(lambda ()
+ (let ((device #$(device-lookup device)))
+ (and device
+ (begin
+ (restart-on-EINTR (swapon device))
+ #t)))))
+ (stop #~(lambda _
+ (let ((device #$(device-lookup device)))
+ (when device
+ (restart-on-EINTR (swapoff device)))
+ #f)))
+ (respawn? #f))))))
(define (swap-service device)
"Return a service that uses @var{device} as a swap device."