Re: [RFC] shared subtrees

[Mike Waychison <Michael.Waychison@Sun.COM>]

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J. Bruce Fields wrote:
> On Mon, Jan 17, 2005 at 01:31:02PM -0500, Mike Waychison wrote:
> 
>>Corner case: how do we handle the case where:
>>
>>mount --make-shared /foo
>>mount --bind /foo /foo/bar
>>
>>A nested --bind without sharing makes sense, but doesn't when sharing is
>>enabled (infinite loop).
> 
> 
> How does this force an infinite loop?  I don't see it.
> 

Well, if I understand it correctly:

(assuming /foo is vfsmount A)

$> mount --make-shared /foo

will make A->A

$> mount --bind /foo /foo/bar

will create a vfsmount B based off A, but because A is in a p-node,
A->B, B->A.

Then, we attach B to A in the vfsmount tree, but because A->B in the
propagation tree, B also gets a vfsmount C added on dentry 'bar'.
Recurse ad infinitum.

Make sense?

- --
Mike Waychison
Sun Microsystems, Inc.
1 (650) 352-5299 voice
1 (416) 202-8336 voice

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