install: 'umount-cow-store' retries upon EBUSY.

Possibly fixes <https://issues.guix.gnu.org/59884>.

* gnu/build/install.scm (umount*): New procedure.
(unmount-cow-store): Use it instead of 'umount'.
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Ludovic Courtès 2022-12-10 14:33:51 +01:00
parent 1ab48edb16
commit 61b7e96877
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@ -1,5 +1,5 @@
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2013-2020, 2022 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2016 Chris Marusich <cmmarusich@gmail.com>
;;; Copyright © 2022 Maxim Cournoyer <maxim.cournoyer@gmail.com>
;;;
@ -282,12 +282,31 @@ (define (set-store-permissions directory)
(mount "/.rw-store" (%store-directory) "" MS_MOVE)
(rmdir "/.rw-store")))
(define (umount* directory)
"Unmount DIRECTORY, but retry a few times upon EBUSY."
(let loop ((attempts 5))
(catch 'system-error
(lambda ()
(umount directory))
(lambda args
(if (and (= EBUSY (system-error-errno args))
(> attempts 0))
(begin
(sleep 1)
(loop (- attempts 1)))
(apply throw args))))))
(define (unmount-cow-store target backing-directory)
"Unmount copy-on-write store."
(let ((tmp-dir "/remove"))
(mkdir-p tmp-dir)
(mount (%store-directory) tmp-dir "" MS_MOVE)
(umount tmp-dir)
;; We might get EBUSY at this point, possibly because of lingering
;; processes with open file descriptors. Use 'umount*' to retry upon
;; EBUSY, leaving a bit of time. See <https://issues.guix.gnu.org/59884>.
(umount* tmp-dir)
(rmdir tmp-dir)
(delete-file-recursively
(string-append target backing-directory))))