ceph: revert commit 22cddde104

commit 22cddde104 breaks the atomicity of write operation, it also
introduces a deadlock between write and truncate.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Greg Farnum <greg@inktank.com>
Conflicts:
	fs/ceph/addr.c

diff --cc fs/ceph/addr.c
Simple merge

diff --cc fs/ceph/file.c
Simple merge

diff --cc fs/ceph/mds_client.c
Simple merge