Re: BUG: Mount ignores mount options

From: Eric W. Biederman
Date: Fri Aug 10 2018 - 21:19:58 EST

David Howells <dhowells@xxxxxxxxxx> writes:

> Eric W. Biederman <ebiederm@xxxxxxxxxxxx> wrote:
>> There is a serious problem with mount options today that fsopen does not
>> address. The problem is that mount options are ignored for block based
>> filesystems, and any other type of filesystem that follows the same
>> pattern.
> Yes. Since you *absolutely* *insist* on this being fixed *right* *now* *or*
> *else*, I'm working up a set of additional patches to give userspace the
> option of whether they want no sharing; sharing, but only with exactly the
> same parameters; or to ignore the parameter differences and just accept
> sharing of what's already already mounted (ie. the current behaviour).
> The second option, however, is not trivial as it needs to compare the fs
> contexts, including the LSM parameters. To make that work, I really need to
> remove the old security_mnt_opts stuff - which means I need to port btrfs to
> the new context stuff.
> We discussed this yesterday, and I proposed a solution, and I'm working on it.

I repeated this because after some comments from Al on IRC yesterday
and Miklos's email replay. It appeared clear that I had not specified
why my issue was clearly enough for people reading the thread to
understand the problem that I see.

> Yes, I agree it would be nice to have, but it *doesn't* really need supporting
> right this minute, since what I have now oughtn't to break the current
> behaviour.

I am really reluctant to endorse anything that propagates the issues of
the current interface in the new mount interface.