linux-kernel - Re: [PATCH v4 0/3] fs: allow statmount to fetch the fs_subtype and sb

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <hss5w5in3wj3af3o2x3v3zfaj47gx6w7faeeuvnxwx2uieu3xu@zqqllubl6m4i>
Date: Wed, 13 Nov 2024 12:27:50 +0100
From: Karel Zak <kzak@...hat.com>
To: Christian Brauner <brauner@...nel.org>
Cc: Jeff Layton <jlayton@...nel.org>, Miklos Szeredi <miklos@...redi.hu>, 
	Ian Kent <raven@...maw.net>, Josef Bacik <josef@...icpanda.com>, 
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Alexander Viro <viro@...iv.linux.org.uk>, Jan Kara <jack@...e.cz>
Subject: Re: [PATCH v4 0/3] fs: allow statmount to fetch the fs_subtype and
 sb_source

On Tue, Nov 12, 2024 at 02:39:21PM GMT, Christian Brauner wrote:
> On Mon, 11 Nov 2024 10:09:54 -0500, Jeff Layton wrote:
> > Meta has some internal logging that scrapes /proc/self/mountinfo today.
> > I'd like to convert it to use listmount()/statmount(), so we can do a
> > better job of monitoring with containers. We're missing some fields
> > though. This patchset adds them.
> > 
> > 
> 
> Applied to the vfs.misc branch of the vfs/vfs.git tree.
> Patches in the vfs.misc branch should appear in linux-next soon.

Jeff, thank you for this!

I have already implemented support for statmount() and listmount() in
libmount (PR: https://github.com/util-linux/util-linux/pull/3092). The
only remaining issue was the mount source and incomplete file system
type.

Currently, the library does not use these syscalls when mounting (it
still uses /proc/#/mountinfo). However, there is already a library API
to fetch mount information from the kernel using listmount+statmount,
and it can be accessed from the command line using:

   findmnt --kernel=listmount

Next on the wish list is a notification (a file descriptor that can be
used in epoll) that returns a 64-bit ID when there is a change in the
mount node. This will enable us to enhance systemd so that it does not
have to read the entire mount table after every change.

    Karel

-- 
 Karel Zak  <kzak@...hat.com>
 http://karelzak.blogspot.com