ToDo/Notes:
- Find and fix bugs.
- In between ntfs_prepare/commit_write, need exclusion between
simultaneous file extensions. This is given to us by holding i_sem
on the inode. The only places in the kernel when a file is resized
are prepare/commit write and ntfs_truncate() for both of which i_sem
is held. Just have to be careful in read-/writepage and other helpers
not running under i_sem that we play nice... Also need to be careful
with initialized_size extention in ntfs_prepare_write and writepage.
UPDATE: The only things that need to be checked are
prepare/commit_write as well as the compressed write and the other
attribute resize/write cases like index attributes, etc. For now
none of these are implem
