file-systems: Remove 'title' field and add <file-system-label>.

The 'title' field was easily overlooked and was an endless source of
confusion.  Now, the value of the 'device' field is self-contained.

* gnu/system/file-systems.scm (<file-system>): Change constructor name
to '%file-system'.
[title]: Remove.
(<file-system-label>): New record type with printer.
(report-deprecation, device-expression)
(process-file-system-declaration, file-system): New macros.
(file-system-title): New procedure.
(file-system->spec, spec->file-system): Adjust to handle
<file-system-label>.
* gnu/system.scm (bootable-kernel-arguments): Add case for
'file-system-label?'.
(read-boot-parameters): Likewise.
(mapped-device-user): Avoid 'file-system-title'.
(fs->boot-device): Remove.
(operating-system-boot-parameters): Use 'file-system-device' instead of
'fs->boot-device'.
(device->sexp): Add case for 'file-system-label?'.
* gnu/bootloader/grub.scm (grub-root-search): Add case for
'file-system-label?'.
* gnu/system/examples/bare-bones.tmpl,
gnu/system/examples/beaglebone-black.tmpl,
gnu/system/examples/lightweight-desktop.tmpl,
gnu/system/examples/vm-image.tmpl: Remove uses of 'title'.
* gnu/system/vm.scm (virtualized-operating-system): Remove uses of
'file-system-title'.
* guix/scripts/system.scm (check-file-system-availability): Likewise,
and adjust fix-it hint.
(check-initrd-modules)[file-system-/dev]: Likewise.
* gnu/build/file-systems.scm (canonicalize-device-spec): Remove 'title'
parameter.
[canonical-title]: Remove.
Match on SPEC's type rather than on CANONICAL-TITLE.
(mount-file-system): Adjust caller.
* gnu/build/linux-boot.scm (boot-system): Interpret ROOT here.
* gnu/services/base.scm (file-system->fstab-entry): Remove use of
'file-system-title'.
* doc/guix.texi (File Systems): Remove documentation of the 'title'
field.  Rewrite documentation of 'device' and document
'file-system-label'.

1 files changed, 8 insertions, 9 deletions

diff --git a/gnu/services/base.scm b/gnu/services/base.scm
index eb82b2ddcf..09a1ce95e3 100644
--- a/gnu/services/base.scm
+++ b/gnu/services/base.scm
@@ -303,15 +303,14 @@ seconds after @code{SIGTERM} has been sent are terminated with
 
 (define (file-system->fstab-entry file-system)
   "Return a @file{/etc/fstab} entry for @var{file-system}."
-  (string-append (case (file-system-title file-system)
-                   ((label)
-                    (string-append "LABEL=" (file-system-device file-system)))
-                   ((uuid)
-                    (string-append
-                     "UUID="
-                     (uuid->string (file-system-device file-system))))
-                   (else
-                    (file-system-device file-system)))
+  (string-append (match (file-system-device file-system)
+                   ((? file-system-label? label)
+                    (string-append "LABEL="
+                                   (file-system-label->string file-system)))
+                   ((? uuid? uuid)
+                    (string-append "UUID=" (uuid->string uuid)))
+                   ((? string? device)
+                    device))
                  "\t"
                  (file-system-mount-point file-system) "\t"
                  (file-system-type file-system) "\t"