upcall_cleanup() is called after every upcall regardless of errors. if we get a CLOSE upcall after a daemon restart, we still call cleanup_close() and crash attempting to access the invalid open state pointer. avoid calling upcall-specific cancel routines for these version mismatch errors
Signed-off-by: Casey Bodley <cbodley@citi.umich.edu>
to determine that the daemon has restarted -- rather that daemon is receiving upcalls from the kernel that were processed by the old instance of the daemon -- add a version to the upcall mechanism.
when daemon starts up it generates a version number (just a timestamp). it passes this value to the driver on start up via "start_ioctl" downcall. the driver saves that value in its device extensions. it uses that value in the mount and shtudown upcalls.
when daemon replies to the mount command it again sends its version as a part of the reply. this reply is stored in driver;s netroot extensions. the driver uses netroot's value in each upcall to the daemon.
if the daemon receives an upcall for an operation where the included version does not equal to the its current version, it fails the upcall (error_code=116).
a restart of the daemon would change driver's device extension value which the driver will then use in the new mount upcalls that would establish new sessions. then the correct daemon version would be returned as a part of the mount downcalled and saved in the netroot.
very similar to the issue with nfs41_open_state, an abandoned upcall could outlive its mount. to prevent their nfs41_root from being freed, upcalls need to hold a reference until they're finished. this also keeps all of its clients/sessions/rpc connections alive
Signed-off-by: Casey Bodley <cbodley@citi.umich.edu>
added call to upcall_cleanup() after both upcall_marshall() and upcall_cancel()
individual upcall operations define their nfs41_upcall_op structs locally, instead of putting tons of function prototypes in upcall.c
made the upcall_marshall() function optional; most marshall functions are noops
Signed-off-by: Casey Bodley <cbodley@citi.umich.edu>
