Messages in this thread | | | Date | Tue, 10 May 2016 16:48:26 +0100 | From | Al Viro <> | Subject | Re: mount --move and shared namespaces |
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On Mon, May 09, 2016 at 06:46:02PM -0400, Phillip Susi wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA512 > > It seems that mount --move does not work on a shared namespace ( now > the default under systemd ), yet you can mount --bind and then umount > the original, which seems to amount to exactly the same thing. Why is > the direct move not allowed?
You have something mounted on /foo and events from /foo propagated to /bar. You move the instance on /foo to /baz; what to do with one on /bar? Propagation from /baz might have nothing whatsoever in common with that on /foo, so "move to the corresponding recepients of events for /baz" is not an answer...
Move *into* shared is allowed - the one you move ends up relocated and cloned, with clones attached to the places where events propagate to. Move *from* shared... No sane semantics.
And no, mount --move is *not* mount --bind + umount - it really moves the vfsmount, so anything sitting in that subtree will find itself at the new location.
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