[0/8] Enospc cleanups and fixes

Message

Josef Bacik Nov. 21, 2018, 7:03 p.m. UTC

The delayed refs rsv patches exposed a bunch of issues in our enospc
infrastructure that needed to be addressed.  These aren't really one coherent
group, but they are all around flushing and reservations.
may_commit_transaction() needed to be updated a little bit, and we needed to add
a new state to force chunk allocation if things got dicey.  Also because we can
end up needed to reserve a whole bunch of extra space for outstanding delayed
refs we needed to add the ability to only ENOSPC tickets that were too big to
satisfy, instead of failing all of the tickets.  There's also a fix in here for
one of the corner cases where we didn't quite have enough space reserved for the
delayed refs we were generating during evict().  Thanks,

Josef