libxfs: sync files with 2.6.38 kernel code

libxfs: sync files with 2.6.38 kernel code

Bring the libxfs headers and code into sync with the 2.6.37 kernel code.
Update the rest of xfsprogs to work with the new code.

Note: this does not convert xfsprogs to the kernel xfs_trans_ijoin\ijoin_ref
interface, it maintains the older ijoin/ihold interface because of the
different way the inode reference counting works in libxfs. More work will be
needed to change it over to a manner compatible with the current kernel API.

Note: log sector size handling needs to be sorted out. Specifically,
initialising l_sectbb_log/l_sectBBsize correctly and removing the hacks in
xlog_bread and friends (libxlog/xfs_log_recover.c) to work around the fact they
are not initialised correctly. (FWIW, I don't think xfsprogs handles large log
sector size correctly as a result, and especially not if the log device sector
size is different to the data device sector size).

Testing:

Currently passes xfstests on x86_64 w/ 4k block sizes and 512 byte block/2k
directory block filesystems. No obvious regressions are occurring during
xfstests runs.

Signed-off-by: Dave Chinner <dchinner@redhat.com>