libceph: add data pointers in osd op structures

An extent type osd operation currently implies that there will
be corresponding data supplied in the data portion of the request
(for write) or response (for read) message.  Similarly, an osd class
method operation implies a data item will be supplied to receive
the response data from the operation.

Add a ceph_osd_data pointer to each of those structures, and assign
it to point to eithre the incoming or the outgoing data structure in
the osd message.  The data is not always available when an op is
initially set up, so add two new functions to allow setting them
after the op has been initialized.

Begin to make use of the data item pointer available in the osd
operation rather than the request data in or out structure in
places where it's convenient.  Add some assertions to verify
pointers are always set the way they're expected to be.

This is a sort of stepping stone toward really moving the data
into the osd request ops, to allow for some validation before
making that jump.

This is the first in a series of patches that resolve:
    http://tracker.ceph.com/issues/4657

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

1 files changed, 20 insertions, 4 deletions

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index c12b55559f16..eb64ed0f228f 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -1315,23 +1315,39 @@ static void rbd_osd_req_format_op(struct rbd_obj_request *obj_request,
 					bool write_request)
 {
 	struct rbd_img_request *img_request = obj_request->img_request;
+	struct ceph_osd_request *osd_req = obj_request->osd_req;
+	struct ceph_osd_data *osd_data = NULL;
 	struct ceph_snap_context *snapc = NULL;
 	u64 snap_id = CEPH_NOSNAP;
 	struct timespec *mtime = NULL;
 	struct timespec now;
 
-	rbd_assert(obj_request->osd_req != NULL);
+	rbd_assert(osd_req != NULL);
 
 	if (write_request) {
+		osd_data = &osd_req->r_data_out;
 		now = CURRENT_TIME;
 		mtime = &now;
 		if (img_request)
 			snapc = img_request->snapc;
-	} else if (img_request) {
-		snap_id = img_request->snap_id;
+	} else {
+		osd_data = &osd_req->r_data_in;
+		if (img_request)
+			snap_id = img_request->snap_id;
 	}
+	if (obj_request->type != OBJ_REQUEST_NODATA) {
+		struct ceph_osd_req_op *op = &obj_request->osd_req->r_ops[0];
 
-	ceph_osdc_build_request(obj_request->osd_req, obj_request->offset,
+		/*
+		 * If it has data, it's either a object class method
+		 * call (cls) or it's an extent operation.
+		 */
+		if (op->op == CEPH_OSD_OP_CALL)
+			osd_req_op_cls_response_data(op, osd_data);
+		else
+			osd_req_op_extent_osd_data(op, osd_data);
+	}
+	ceph_osdc_build_request(osd_req, obj_request->offset,
 			snapc, snap_id, mtime);
 }