~ruther/guix-local: shell: Don’t rely on atime for caching.

eb83cceb7eb2774e9d7ff90317ab1d0dcf350f2c — Ludovic Courtès 5 months ago 7d488fe

shell: Don’t rely on atime for caching.

Relying on atime was fine even on ‘noatime’ file systems because the atime was
explicitly updated.  However, on file systems with atime enabled, cache items
were potentially retained for too long since scanning the cache directory
could update atimes.

* guix/scripts/shell.scm (options-with-caching): In ‘utime’ call, change both
the mtime and the atime.
(guix-shell)[entry-expiration]: Use ‘file-expiration-time’ with ‘stat:mtime’.

Change-Id: Ibe2aedae41a1018a95c2efe7f2dcf08bd1caae2a

patch browse .tar.gz

1 files changed, 4 insertions(+), 8 deletions(-)

M guix/scripts/shell.scm

M guix/scripts/shell.scm => guix/scripts/shell.scm +4 -8

@@ 250,10 250,8 @@ cache) or a 'gc-root' key (to add the profile to cache)."
              stat
              (<= timestamp (stat:mtime stat)))
         (let ((now (current-time)))
-          ;; Update the atime on ROOT to reflect usage.
-          (utime root
-                 now (stat:mtime stat) 0 (stat:mtimensec stat)
-                 AT_SYMLINK_NOFOLLOW)
+          ;; Update the mtime on ROOT to reflect usage.
+          (utime root now now 0 0 AT_SYMLINK_NOFOLLOW)
           (alist-cons 'profile root
                       (remove (match-lambda
                                 (('load . _) #t)


@@ 566,11 564,9 @@ concatenates MANIFESTS, a list of expressions."
                     (file (string-append directory "/" file)))
                   (or (scandir directory) '())))
 
-    (define* (entry-expiration file)
+    (define entry-expiration
       ;; Return the time at which FILE, a cached profile, is considered expired.
-      (match (false-if-exception (lstat file))
-        (#f 0)                       ;FILE may have been deleted in the meantime
-        (st (+ (stat:atime st) (* 60 60 24 7)))))
+      (file-expiration-time (* 60 60 24 7) stat:mtime))
 
     (define opts
       (parse-args args))