xfs: continue removing defer item boilerplate [v2]

Now that we've restructured log intent item recovery to reconstruct the
incore deferred work state, apply further cleanups to that code to
remove boilerplate that is duplicated across all the _item.c files.
Having done that, collapse a bunch of trivial helpers to reduce the
overall call chain.  That enables us to refactor the relog code so that
the ->relog_item implementations only have to know how to format the
implementation-specific data encoded in an intent item and don't
themselves have to handle the log item juggling.

v2: pick up rvb tags

This has been lightly tested with fstests.  Enjoy!

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
xfs: move ->iop_relog to struct xfs_defer_op_type

The only log items that need relogging are the ones created for deferred
work operations, and the only part of the code base that relogs log
items is the deferred work machinery.  Move the function pointers.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
8 files changed