On 18.04.2016 15:22, Karel Zak wrote:
On Mon, Apr 18, 2016 at 02:51:37PM +0300, Yuriy M. Kaminskiy wrote:
Karel Zak <kzak@xxxxxxxxxx> writes:
On Fri, Mar 18, 2016 at 05:26:25AM +0300, Yuriy M. Kaminskiy wrote:
I think this issue should be at least documented. And, maybe, default
`--propagation` should be changed to `slave`.
The reason why we use 'private' is that it's the kernel default for
years and it's what has been expected by users for long time before we
introduced --propagation and any unshare(1) default.
The current --propagation default unifies things and makes unshare(1)
portable to distributions where root fs is mounted as 'shared' (e.g.
systemd distros) and all this in backwardly compatible way for users
Opposite. It does not change anything for older systems, but breaks
things for new systems.
who have no clue about --propagation.
And it is *especially* harmful for users that are not aware about
--propagation. As private (new 2.27+ default) break umount propagation,
and results in nasty surprises (up to data loss).
So, I don't think we want to change any default to corrupt scripts where
is no explicitly specified --propagation.
By you already broke scripts that expected old a-la '--propagation
unchanged' behavior.
Only if your system uses something else that kernel default 'private'
and you depend on this non-default setting. (IMHO relatively small
groups of users)
All systemd systems use shared. Which is not "small group of users".
The old "--propagation unchanged" makes unshare useless on some
mainstream distros where default is 'shared'.
No, it is not. --propagation does not do *anything* that cannot be done
without it. On pre-2.27 util-linux,
unshare -m sh -c 'mount --make-rprivate /; ...'
does exactly same as `unshare -m [--propagation=private] ...` in 2.27+.
Reverse is not true! With 2.27 you *must* use new
[backward-incompatible] options to revert to sane behavior [which is
*slave*, not *private*].
Anyway, we will not change any default now.
--
To unsubscribe from this list: send the line "unsubscribe util-linux" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
