From: Zdenek Kabelac <zdenek.kabelac@gmail.com>
To: LVM general discussion and development <linux-lvm@redhat.com>,
Pascal <patatetom@gmail.com>
Subject: Re: [linux-lvm] LVM and RO device/partition(s)
Date: Mon, 20 Mar 2023 14:57:49 +0100 [thread overview]
Message-ID: <5b9e31d6-2675-8903-619c-cf33c48f1ba8@gmail.com> (raw)
In-Reply-To: <CAGhAaddYD7Y8ObY6Q3Yprhruzb8s6-q0t+GJUv5oYGLR3LCpRg@mail.gmail.com>
Dne 19. 03. 23 v 11:27 Pascal napsal(a):
> hi,
>
> the bio_check_ro function of the blk-core.c source file of the Linux kernel
> refers to LVM :
> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/block/blk-core.c?h=v6.2.7#n500 <https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/block/blk-core.c?h=v6.2.7#n500>
>
> how does LVM currently behave when faced with a device marked as readonly ?
> does it automatically switch itself in readonly mode?
>
> according to some tests carried out in a virtual machine, it seems that it
> doesn't and that LVM modifies the disk/partition(s) even though they are all
> readonly (chmod 444 && blockdev --setro).
Hi
There is no extra logic around RO devices in lvm2. When lvm2 succeeds opening
device in write mode, it'll use it for writing.
Also note - when you 'activate' a LV in read-write mode - someone opens such
LV/device and you later on 'lvchange' such active LV to read-only mode - all
writers will keep writing to such device.
It's not quite clear which kind of problem you are actually hitting - so maybe
adding some more descriptive environment + logs might give more info about
your individual case.
Note: root admin typically can overwrite any 'mild' protections...
Regards
Zdenek
_______________________________________________
linux-lvm mailing list
linux-lvm@redhat.com
https://listman.redhat.com/mailman/listinfo/linux-lvm
read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
next prev parent reply other threads:[~2023-03-20 14:00 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-19 10:27 [linux-lvm] LVM and RO device/partition(s) Pascal
2023-03-20 13:57 ` Zdenek Kabelac [this message]
2023-03-20 14:15 ` lacsaP Patatetom
2023-03-20 16:37 ` lacsaP Patatetom
2023-03-22 14:11 ` [linux-lvm] LVM and RO device/partition(s Zdenek Kabelac
2023-03-22 14:50 ` lacsaP Patatetom
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5b9e31d6-2675-8903-619c-cf33c48f1ba8@gmail.com \
--to=zdenek.kabelac@gmail.com \
--cc=linux-lvm@redhat.com \
--cc=patatetom@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).