coda: switch to ->read_iter/->write_iter

... and request the same from the local cache - all filesystems with
anything usable for that support those already.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2015-04-03 10:58:11 -04:00
commit c12c49e702