[RFC] Payloads and transient filesystem support for user-cr

[Dan Smith]

DL> The posix semaphore use the mapped deleted hardlinked files.

DL> AFAIK, the current implementation do not support that, no ?
DL> How is it possible to CR programs using sem_* operations in this case ?

You're right.  This addresses the problem of /dev/shm/sem.foo going away
when the container's /dev/shm mount is destroyed.  It does not address
the fact that the mmap()'d unlinked file is restored as an anonymous
region and therefore becomes disjoint with the one on-disk.  I expect
the evolution of the unlinked files patches will resolve that.

Our naive tests are not discriminating enough to make this distinction
at the moment, which certainly needs to be resolved :)

-- 
Dan Smith
IBM Linux Technology Center
email: danms at us.ibm.com