Re: [RFC] shared subtrees

["J. Bruce Fields" <bfields@fieldses.org>]

On Tue, Feb 01, 2005 at 04:15:36PM -0500, Mike Waychison wrote:
> No.  I want to allow the mount.  However, if there are several shared
> '/home' (through CLONE_NS or mount --bind), there remains the following
> two key problems:
> 
> - - How do you expire the mounts and umount them?  (undefined with shared
> subtrees thus far)
> - - How do you handle the case where '/home/mikew' is automounted in all
> instances of it, and then umounted in a single namespace.  Walking back
> into '/home/mikew' in that namespace will trigger the daemon to mount
> again, but the filesystem is already mounted in it's namespace.
> 
> I guess a solution to ponder is what if we included the following rule:
> 
> "An attempt to umount a vfsmount X will induce the umounting of all
> vfsmounts in X's p-node as well as all vfsmounts/p-nodes 'owned' by said
> p-node."

>From Viro's proposal:

> 	5. umount
> umount everything that gets propagation from victim.

I think that agrees with your description.

What *should* be the behaviour when someone unmounts something that was
mounted by the automounter?  That seems like a strange thing to do.

--b.