cleanup error tags

[Christoph Hellwig <hch@lst.de>]

Hi all,

while adding error injection to new code I'm writing I got really annoyed
with all the places error tags had to be added.  This series cleans the
error tags so that only the definition and one table have to be updated.
I've also cleaned up a lot of the surroundings while at it.

Diffstat:
 libxfs/xfs_ag_resv.c    |    7 -
 libxfs/xfs_alloc.c      |    5 -
 libxfs/xfs_attr_leaf.c  |    2 
 libxfs/xfs_bmap.c       |   17 +--
 libxfs/xfs_btree.c      |    2 
 libxfs/xfs_da_btree.c   |    2 
 libxfs/xfs_dir2.c       |    2 
 libxfs/xfs_errortag.h   |   94 ++++++++++----------
 libxfs/xfs_exchmaps.c   |    4 
 libxfs/xfs_ialloc.c     |    2 
 libxfs/xfs_inode_buf.c  |    4 
 libxfs/xfs_inode_fork.c |    3 
 libxfs/xfs_metafile.c   |    2 
 libxfs/xfs_refcount.c   |    7 -
 libxfs/xfs_rmap.c       |    2 
 libxfs/xfs_rtbitmap.c   |    2 
 scrub/cow_repair.c      |    4 
 scrub/repair.c          |    2 
 xfs_attr_item.c         |    2 
 xfs_buf.c               |    4 
 xfs_error.c             |  216 ++++++------------------------------------------
 xfs_error.h             |   47 ++++------
 xfs_inode.c             |   28 ++----
 xfs_iomap.c             |    4 
 xfs_log.c               |    8 -
 xfs_trans_ail.c         |    2 
 26 files changed, 153 insertions(+), 321 deletions(-)