[PATCH 0/9 V2] xfs_db, xfs_repair: improve CRC error detection

[Dave Chinner]

Hi folks,

This is version 2 of the patchset first posted here:

http://oss.sgi.com/archives/xfs/2014-04/msg00374.html

The version corrects all the issues mentioned in the first review.
It doesn't try to rework the directory buffer read issue that
Christoph was concerned about - API changes are necessary so we'll
do that through the kernel first in a separate patchset.

Version 2:
- move LIBXFS_B_UNCHECKED to the correct patch (patch 1)
- set_cur_iotype assumes a valid type (patch 2)
- comments added to explain the way LIBXFS_B_UNCHECKED and dirty
  buffers are supposed to interact (patch 3)
- fixed comment flow and added separate "crc_error" return variable
  to dir_read_buf() (patch 4)
- reworked CRC error handling of AG headers (patch 5)
- readded missing dirty/no_modify assert (patch 6)
- fixed typos (patch 8)
- fixed "repair" variable initialisation flow (patch 9)
- fixed dirty buffer accounting on the cursor to dirty the correct
  buffer on CRC errors, added some clarifying comments (patch 9)

Comments and testing welcome!

-Dave.