libceph: update osd request/reply encoding

Use the new version of the encoding for osd requests and replies.  In the
process, update the way we are tracking request ops and reply lengths and
results in the struct ceph_osd_request.  Update the rbd and fs/ceph users
appropriately.

The main changes are:
 - we keep pointers into the request memory for fields we need to update
   each time the request is sent out over the wire
 - we keep information about the result in an array in the request struct
   where the users can easily get at it.

Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Alex Elder <elder@inktank.com>

1 files changed, 24 insertions, 28 deletions

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 22085e86a409..6c81a4c040b9 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -196,7 +196,7 @@ struct rbd_obj_request {
 
 	u64			xferred;	/* bytes transferred */
 	u64			version;
-	s32			result;
+	int			result;
 	atomic_t		done;
 
 	rbd_obj_callback_t	callback;
@@ -1282,12 +1282,19 @@ static void rbd_osd_trivial_callback(struct rbd_obj_request *obj_request)
 
 static void rbd_osd_read_callback(struct rbd_obj_request *obj_request)
 {
-
 	dout("%s: obj %p result %d %llu/%llu\n", __func__, obj_request,
 		obj_request->result, obj_request->xferred, obj_request->length);
-	if (obj_request->result == (s32) -ENOENT) {
+	/*
+	 * ENOENT means a hole in the object.  We zero-fill the
+	 * entire length of the request.  A short read also implies
+	 * zero-fill to the end of the request.  Either way we
+	 * update the xferred count to indicate the whole request
+	 * was satisfied.
+	 */
+	if (obj_request->result == -ENOENT) {
 		zero_bio_chain(obj_request->bio_list, 0);
 		obj_request->result = 0;
+		obj_request->xferred = obj_request->length;
 	} else if (obj_request->xferred < obj_request->length &&
 			!obj_request->result) {
 		zero_bio_chain(obj_request->bio_list, obj_request->xferred);
@@ -1298,20 +1305,14 @@ static void rbd_osd_read_callback(struct rbd_obj_request *obj_request)
 
 static void rbd_osd_write_callback(struct rbd_obj_request *obj_request)
 {
-	dout("%s: obj %p result %d %llu/%llu\n", __func__, obj_request,
-		obj_request->result, obj_request->xferred, obj_request->length);
-
-	/* A short write really shouldn't occur.  Warn if we see one */
-
-	if (obj_request->xferred != obj_request->length) {
-		struct rbd_img_request *img_request = obj_request->img_request;
-		struct rbd_device *rbd_dev;
-
-		rbd_dev = img_request ? img_request->rbd_dev : NULL;
-		rbd_warn(rbd_dev, "wrote %llu want %llu\n",
-			obj_request->xferred, obj_request->length);
-	}
-
+	dout("%s: obj %p result %d %llu\n", __func__, obj_request,
+		obj_request->result, obj_request->length);
+	/*
+	 * There is no such thing as a successful short write.
+	 * Our xferred value is the number of bytes transferred
+	 * back.  Set it to our originally-requested length.
+	 */
+	obj_request->xferred = obj_request->length;
 	obj_request_done_set(obj_request);
 }
 
@@ -1329,9 +1330,6 @@ static void rbd_osd_req_callback(struct ceph_osd_request *osd_req,
 				struct ceph_msg *msg)
 {
 	struct rbd_obj_request *obj_request = osd_req->r_priv;
-	struct ceph_osd_reply_head *reply_head;
-	struct ceph_osd_op *op;
-	u32 num_ops;
 	u16 opcode;
 
 	dout("%s: osd_req %p msg %p\n", __func__, osd_req, msg);
@@ -1339,22 +1337,19 @@ static void rbd_osd_req_callback(struct ceph_osd_request *osd_req,
 	rbd_assert(!!obj_request->img_request ^
 				(obj_request->which == BAD_WHICH));
 
-	reply_head = msg->front.iov_base;
-	obj_request->result = (s32) le32_to_cpu(reply_head->result);
+	if (osd_req->r_result < 0)
+		obj_request->result = osd_req->r_result;
 	obj_request->version = le64_to_cpu(osd_req->r_reassert_version.version);
 
-	num_ops = le32_to_cpu(reply_head->num_ops);
-	WARN_ON(num_ops != 1);	/* For now */
+	WARN_ON(osd_req->r_num_ops != 1);	/* For now */
 
 	/*
 	 * We support a 64-bit length, but ultimately it has to be
 	 * passed to blk_end_request(), which takes an unsigned int.
 	 */
-	op = &reply_head->ops[0];
-	obj_request->xferred = le64_to_cpu(op->extent.length);
+	obj_request->xferred = osd_req->r_reply_op_len[0];
 	rbd_assert(obj_request->xferred < (u64) UINT_MAX);
-
-	opcode = le16_to_cpu(op->op);
+	opcode = osd_req->r_request_ops[0].op;
 	switch (opcode) {
 	case CEPH_OSD_OP_READ:
 		rbd_osd_read_callback(obj_request);
@@ -1719,6 +1714,7 @@ static void rbd_img_obj_callback(struct rbd_obj_request *obj_request)
 		more = blk_end_request(img_request->rq, result, xferred);
 		which++;
 	}
+
 	rbd_assert(more ^ (which == img_request->obj_request_count));
 	img_request->next_completion = which;
 out: