Merge wapbl_replay_get_inodes into wapbl_replay_prescan. Change the
logic to determine the head: It doesn't make sense to update it if the
last inode record seen was not the beginning of the journal, as the
beginning of the journal might not be 0, so always update inodeshead.
transactions. The initial prescan has already sorted out what blocks are
in the journal and removed any revoced blocks, so the hash table is
authorative.
This changes the order of hook processing as the copy-on-write handlers
are called after the journal processing. This makes more sense as the
journal overwrite is logically part of the disk IO.
Add Wasabi System's WAPBL (Write Ahead Physical Block Logging)
journaling code. Originally written by Darrin B. Jewell while
at Wasabi and updated to -current by Antti Kantee, Andy Doran,
Greg Oster and Simon Burge.
OK'd by core@, releng@.
