Fixed broken offset use in vfs_unbusy_pages() which resulted in several different types of panics/inconsistencies with NFS clients. Cleared PG_WANTED where appropriate. Added checks for buffer busy in allocbuf and biodone.
Fixed broken offset use in vfs_unbusy_pages() which resulted in several
different types of panics/inconsistencies with NFS clients.
Cleared PG_WANTED where appropriate.
Added checks for buffer busy in allocbuf and biodone.

Reviewed by:	John Dyson

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