[PATCH 05/14] xfs: make AIL tail pushing independent of the grant lock

[Christoph Hellwig]

Once l_tail_lsn and l_last_sync_lsn are converted to atomic64_ts later
in the series passing them in separately becomes pointless again.  Maybe
scale the patch back a bit and require the caller to hold l_grant_lock
for now, until the atomic64_t conversion happens.