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authorMathieu Othacehe <m.othacehe@gmail.com>2020-02-27 16:22:28 +0100
committerLudovic Courtès <ludo@gnu.org>2020-03-05 23:40:24 +0100
commit64704be417ab6f2788e8e3bc36fede1db35470e7 (patch)
tree41b8a40b82929f581e6d7fdc6810c70e73ab0cb4 /gnu
parentccb1a8c437fa40760899ae95f9d3f10ed7c8b41b (diff)
installer: Fix cow-store umount.
This fixes <https://bugs.gnu.org/39712>. The guix-daemon was preventing the cow-store umount, so restart it. Some udevd workers, using cow-store files might also still be around, so have some umount retries. * gnu/installer/final.scm (kill-cow-users): New procedure, (umount-cow-store): restart guix-daemon and kill all processes started from within the cow-store before trying to umount the store overlay. Also try 5 times to umount the overlay in case it is still busy.
Diffstat (limited to 'gnu')
-rw-r--r--gnu/installer/final.scm77
1 files changed, 71 insertions, 6 deletions
diff --git a/gnu/installer/final.scm b/gnu/installer/final.scm
index 869be8814b..3c170e5d0f 100644
--- a/gnu/installer/final.scm
+++ b/gnu/installer/final.scm
@@ -28,6 +28,12 @@
#:use-module (gnu build accounts)
#:use-module ((gnu system shadow) #:prefix sys:)
#:use-module (rnrs io ports)
+ #:use-module (srfi srfi-1)
+ #:use-module (ice-9 ftw)
+ #:use-module (ice-9 popen)
+ #:use-module (ice-9 match)
+ #:use-module (ice-9 format)
+ #:use-module (ice-9 rdelim)
#:export (install-system))
(define %seed
@@ -97,14 +103,73 @@ USERS."
(write-passwd password (string-append etc "/passwd"))
(write-shadow shadow (string-append etc "/shadow")))
+(define* (kill-cow-users cow-path #:key (spare '("udevd")))
+ "Kill all processes that have references to the given COW-PATH in their
+'maps' file. The process whose names are in SPARE list are spared."
+ (define %not-nul
+ (char-set-complement (char-set #\nul)))
+
+ (let ((pids
+ (filter-map (lambda (pid)
+ (call-with-input-file
+ (string-append "/proc/" pid "/maps")
+ (lambda (port)
+ (and (string-contains (get-string-all port)
+ cow-path)
+ (string->number pid)))))
+ (scandir "/proc" string->number))))
+ (for-each (lambda (pid)
+ ;; cmdline does not always exist.
+ (false-if-exception
+ (call-with-input-file
+ (string-append "/proc/" (number->string pid) "/cmdline")
+ (lambda (port)
+ (match (string-tokenize (read-string port) %not-nul)
+ ((argv0 _ ...)
+ (unless (member (pk (basename argv0)) spare)
+ (syslog "Killing process ~a~%" pid)
+ (kill pid SIGKILL)))
+ (_ #f))))))
+ pids)))
+
(define (umount-cow-store)
"Remove the store overlay and the bind-mount on /tmp created by the
-cow-store service."
- (let ((tmp-dir "/remove"))
- (mkdir-p tmp-dir)
- (mount (%store-directory) tmp-dir "" MS_MOVE)
- (umount tmp-dir)
- (umount "/tmp")))
+cow-store service. This procedure is very fragile and a better approach would
+be much appreciated."
+
+ ;; Remove when integrated in (gnu services herd).
+ (define (restart-service name)
+ (with-shepherd-action name ('restart) result
+ result))
+
+ (catch #t
+ (lambda ()
+ (let ((tmp-dir "/remove"))
+ (mkdir-p tmp-dir)
+ (mount (%store-directory) tmp-dir "" MS_MOVE)
+
+ ;; The guix-daemon has possibly opened files from the cow-store,
+ ;; restart it.
+ (restart-service 'guix-daemon)
+
+ ;; Kill all processes started while the cow-store was active (logins
+ ;; on other TTYs for instance).
+ (kill-cow-users tmp-dir)
+
+ ;; Try to umount the store overlay. Some process such as udevd
+ ;; workers might still be active, so do some retries.
+ (let loop ((try 5))
+ (sleep 1)
+ (let ((umounted? (false-if-exception (umount tmp-dir))))
+ (if (and (not umounted?) (> try 0))
+ (loop (- try 1))
+ (if umounted?
+ (syslog "Umounted ~a successfully.~%" tmp-dir)
+ (syslog "Failed to umount ~a.~%" tmp-dir)))))
+
+ (umount "/tmp")))
+ (lambda args
+ (syslog "~a~%" args))))
(define* (install-system locale #:key (users '()))
"Create /etc/shadow and /etc/passwd on the installation target for USERS.