On Tue, 10 May 2022 at 15:15, Miklos Szeredi [off-list ref] wrote:

On Tue, 10 May 2022 at 13:53, Christian Brauner [off-list ref] wrote:

quoted

quoted

What exactly are the attributes that systemd requires?

We keep a repo with ideas for (kernel) extensions - we should probably
publish that somewhere - but the list we used for a prototype roughly
contains:

* mount flags MOUNT_ATTR_RDONLY etc.
* time flags MOUNT_ATTR_RELATIME etc. (could probably be combined with
  mount flags. We missed the opportunity to make them proper enums
  separate from other mount flags imho.)
* propagation "flags" (MS_SHARED)
* peer group
* mnt_id of the mount
* mnt_id of the mount's parent
* owning userns

Sounds good thus far.   And hey, we don't even need a new syscall:
statx(2) could handle these fine.

Oh, we need this indexed with a mount id, which statx can't do.  So
indeed, a new syscall may be the best choice.

Thanks,
Miklos