From: "Ludovic Courtès" <ludovic.courtes@inria.fr>
To: 46292@debbugs.gnu.org
Cc: Dimitri DELABROYE <dimitri.delabroye@inria.fr>
Subject: bug#46292: ‘guix environment -C’ fails with Linux 4.19 (Debian)
Date: Thu, 18 Feb 2021 12:36:07 +0100 [thread overview]
Message-ID: <878s7lsj4o.fsf@gnu.org> (raw)
In-Reply-To: <87h7ms8658.fsf@inria.fr> ("Ludovic Courtès"'s message of "Thu, 04 Feb 2021 11:43:47 +0100")
Ludovic Courtès <ludovic.courtes@inria.fr> skribis:
> The read-only remount comes from ‘mount-file-system’ in (gnu build
> file-systems):
>
> ;; 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)))
> (let ((flags (logior MS_BIND MS_REMOUNT MS_RDONLY)))
> (mount source mount-point type flags #f)))
>
> This recipe has been working well “forever”, although it’s probably
> unnecessary with recent kernels (the LWN article is from 2008).
Apparently the extra remount is still necessary, and the ‘mount’ command
does it for you if you combine ‘--bind’ with ‘-o ro’:
--8<---------------cut here---------------start------------->8---
# strace -e mount mount --bind -o ro t m
mount("/tmp/t", "/tmp/m", 0xde1930, MS_RDONLY|MS_BIND, NULL) = 0
mount("none", "/tmp/m", NULL, MS_RDONLY|MS_REMOUNT|MS_BIND, NULL) = 0
+++ exited with 0 +++
# mount --version
mount from util-linux 2.35.1 (libmount 2.35.1: btrfs, namespaces, assert, debug)
# uname -sr
Linux 5.10.10-gnu
--8<---------------cut here---------------end--------------->8---
Ludo’.
next prev parent reply other threads:[~2021-02-18 11:37 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-04 10:43 bug#46292: ‘guix environment -C’ fails with Linux 4.19 (Debian) Ludovic Courtès
2021-02-04 12:38 ` zimoun
2021-02-04 14:41 ` Ludovic Courtès
2021-02-10 6:04 ` bug#46292: more info Lucas Nussbaum
2021-02-18 11:38 ` bug#46292: ‘guix environment -C’ fails with Linux 4.19 (Debian) Ludovic Courtès
2021-02-18 13:23 ` Lucas Nussbaum
2021-02-22 9:46 ` Ludovic Courtès
2021-02-22 10:57 ` Lucas Nussbaum
2021-02-22 13:59 ` Ludovic Courtès
2021-02-22 16:44 ` bug#46292: [PATCH 1/3] syscalls: Define MS_RELATIME Ludovic Courtès
2021-02-22 16:44 ` bug#46292: [PATCH 2/3] syscalls: Add 'mounts' and the <mount> record type Ludovic Courtès
2021-02-22 16:44 ` bug#46292: [PATCH 3/3] file-systems: 'mount-file-system' preserves source flags for bind mounts Ludovic Courtès
2021-02-25 10:43 ` bug#46292: ‘guix environment -C’ fails with Linux 4.19 (Debian) Ludovic Courtès
2021-02-18 11:36 ` Ludovic Courtès [this message]
2021-03-09 16:19 ` bug#46292: Reopen Andreas Enge
2021-03-09 20:55 ` Andreas Enge
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