Add setup-pmfs.sh
Add backing_dev parameter in PMFS mount
Add cache.c - nothing there now.
Cache: open backing device support
cache exit support
bs_path_name fix; factor pmfs_cache_init
Add bankshot2_mmap interface to mmap code
Replace struct bankshot2_device by void pointer, so as not to pollute kernel space.
Add bankshot2_xip_file_mmap hook API to mm/mmap.
Rename the hook simply to mmap.
bankshot2_unmap in mm/filemap_xip.c
Add vm_munmap_page. Need more test, and pgoff needs more attention.
Export vma interval tree operations
Retrun vma to bankshot2 to insert into extent tree
Add bankshot2_mm_populate to fix the MAP_POPULATE issue