On 1/23/21 6:44 PM, Graham Cobb wrote:
[...]

I gave a few very simple examples, but I can think of many more cases
where a disk may contain files which users might be able to access if
the disk was mounted (maybe the disk has subvols used by many different
systems but UIDs are not coordinated, or ...).  And, of course, if they
can open a FD during the brief time it is mounted, they can stop it
being unmounted again.

No. If I have chosen to mount just a subvol, it is because I don't want
to mount the whole disk.

I agree with Graham, if we have to mount the root subvolume, it means
that the api is not so good.
Moreover, as explained also by you, the xattr are "exposed" to the risk
of be copied by a simple rsync -X (or cp --preserve=all ...)

BR
G.Baroncelli


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