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authorLudovic Courtès <ludo@gnu.org>2015-04-20 22:16:13 +0200
committerLudovic Courtès <ludo@gnu.org>2015-04-20 22:16:13 +0200
commitb86fee7848f964da4d5e695dc8027d95d40a1c77 (patch)
treead0c6ef4421da2f5de4fce27170db7a82e8ac74d /gnu/build
parent38cf2ba084881a4c8fca0ee2888b5fd5724e9104 (diff)
file-systems: Use a second 'mount' call for read-only bind mounts.
* gnu/build/file-systems.scm (MS_REMOUNT): New constant. (mount-file-system): Add 'flags' local variable. When FLAGS has MS_BIND & MS_RDONLY, call 'mount' with MS_REMOUNT. * gnu/services/base.scm (file-system-service) <start>: Likewise.
Diffstat (limited to 'gnu/build')
-rw-r--r--gnu/build/file-systems.scm17
1 files changed, 13 insertions, 4 deletions
diff --git a/gnu/build/file-systems.scm b/gnu/build/file-systems.scm
index 38e4851515..dc99d60d3d 100644
--- a/gnu/build/file-systems.scm
+++ b/gnu/build/file-systems.scm
@@ -1,5 +1,5 @@
;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2014 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2014, 2015 Ludovic Courtès <ludo@gnu.org>
;;;
;;; This file is part of GNU Guix.
;;;
@@ -55,6 +55,7 @@
(define MS_NOSUID 2)
(define MS_NODEV 4)
(define MS_NOEXEC 8)
+(define MS_REMOUNT 32)
(define MS_BIND 4096)
(define MS_MOVE 8192)
@@ -280,13 +281,21 @@ run a file system check."
(match spec
((source title mount-point type (flags ...) options check?)
(let ((source (canonicalize-device-spec source title))
- (mount-point (string-append root "/" mount-point)))
+ (mount-point (string-append root "/" mount-point))
+ (flags (mount-flags->bit-mask flags)))
(when check?
(check-file-system source type))
(mkdir-p mount-point)
- (mount source mount-point type (mount-flags->bit-mask flags)
+ (mount source mount-point type flags
(if options
(string->pointer options)
- %null-pointer))))))
+ %null-pointer))
+
+ ;; For read-only bind mounts, an extra remount is needed, as per
+ ;; <http://lwn.net/Articles/281157/>, which still applies to Linux 4.0.
+ (when (and (= MS_BIND (logand flags MS_BIND))
+ (= MS_RDONLY (logand flags MS_RDONLY)))
+ (mount source mount-point type (logior MS_BIND MS_REMOUNT MS_RDONLY)
+ %null-pointer))))))
;;; file-systems.scm ends here