I don't know. Can you describe how your driver implements the remapping?
I have tested with ext2. I get double faults when trying to sync.What are those? (By the look of the error message, I can see they are not something I want to have :-)
I'm at loss how all of this can happend. All I do is to allocate BIOs and kernel memory, process the BIOs and deal with deallocation afterwards.
Thomas