[PATCH 00/10] remove xfsbufd

[Christoph Hellwig]

Now that we all dirty metadata is tracked in the AIL, and except for few
special cases only written through it there is no point to keep the current
delayed buffers list and xfsbufd around.

This series remove a few more of the remaining special cases and then
replaced the global delwri buffer list with a local on-stack one.  The
main consumer is xfsaild, which is used more often now.

Besides removing a lot of code this change reduce buffer cache lookups
on loaded systems from xfsaild because we can figure out that a buffer
already is under writeback entirely locally now.