On Thu, Aug 19, 2021 at 03:18:15PM -0400, Jeff Layton wrote:

On Wed, 2021-08-18 at 11:34 +0200, Rodrigo Campos wrote:

quoted

On Tue, Aug 17, 2021 at 6:49 PM Eric W. Biederman [off-list ref] wrote:

quoted

Matthew Wilcox [off-list ref] writes:

quoted

On Fri, Aug 13, 2021 at 05:49:19PM -0700, Andy Lutomirski wrote:

quoted

[0] we have mandatory locks, too. Sigh.

I'd love to remove that.  Perhaps we could try persuading more of the
distros to disable the CONFIG option first.

Yes.  The support is disabled in RHEL8.

If it helps, it seems to be enabled on the just released debian stable:
    $ grep CONFIG_MANDATORY_FILE_LOCKING /boot/config-5.10.0-8-amd64
    CONFIG_MANDATORY_FILE_LOCKING=y

Also the new 5.13 kernel in experimental has it too:
    $ grep CONFIG_MANDATORY_FILE_LOCKING /boot/config-5.13.0-trunk-amd64
    CONFIG_MANDATORY_FILE_LOCKING=y

A pity. It would have been nice if they had turned it off a while ago. I
guess I should have done more outreach at the time. Sigh...

Would it be acceptable to add a warning when MS_MANDLOCK is passed to
mount() and backport this to stable kernels in order to get reports
of any such use in a reasonably short time ? Anyway it sounds
important to at least warn about deprecation.

Willy