[GIT PULL] XFS update for 2.6.28

[Christoph Hellwig]

Now that the pull request was to late can we at least cherry pick some
fixes?

That'd be at least:

>       [XFS] Account for allocated blocks when expanding

>       [XFS] Fix use-after-free with log and quotas
>       [XFS] Unlock inode before calling xfs_idestroy()
>       [XFS] Wait for all I/O on truncate to zero file size

and we probably want the log allocation failure handling patch from Dave
that's not in yet, as it is on the regression list.