[PATCH 0/3] xfs_io: new functions

[Dave Chinner]

This is just a couple of additional functions for xfs_io I have had
sitting around for a while. The first is an interface to
sync_file_range() for better control of file writeback.  The second
and third introduce vectored pread/pwrite so that I could simulate
the same style of vectored IO that KVM does via direct IO (hint -
tracing indicated that the generic direct IO code doesn't handle
this particularly efficiently).