From: Jeff Layton

Sent: 18 September 2023 15:30

....

A bit tangential to this discussion, but one thing we could consider is
adding something like a mnt_change_cookie field that increments on any
significant changes on the mount: i.e. remounts with new options,
changes to parentage or propagation, etc.

That might make it more palatable to do something with separate syscalls
for the string-based fields. You could do:

statmnt(...);
getmntattr(mnt, "mnt.fstype", ...);
statmnt(...);

...and then if the mnt_change_cookie hasn't changed, you know that the
string option was stable during that window.

That would also help with the problem of the mount options
being changed while processing a page fault on the user buffer.

Of, with a call to just get the cookie, could find that nothing
has changed so there is no point looking again.

	David

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