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Commit 7114edac authored by Ilya Dryomov's avatar Ilya Dryomov
Browse files

rbd: new request completion code 



Do away with partial request completions and all the associated
complexity.  Individual object requests no longer need to be completed
in order -- when the last one becomes ready, we complete the entire
higher level request all at once.

This also wraps up the conversion to a state machine model and
eliminates the recursion described in commit 6d69bb53 ("rbd:
prevent kernel stack blow up on rbd map").

Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
parent efbd1a11

drivers/block/rbd.c

+55 −13
Original line number Diff line number Diff line
@@ -327,6 +327,7 @@ struct rbd_img_request { 
	int			result;	/* first nonzero obj_request result */



	u32			obj_request_count;

	u32			pending_count;

	struct list_head	obj_requests;	/* rbd_obj_request structs */



	struct kref		kref;
@@ -1406,6 +1407,7 @@ static inline void rbd_img_obj_request_add(struct rbd_img_request *img_request, 
	obj_request_img_data_set(obj_request);

	rbd_assert(obj_request->which != BAD_WHICH);

	img_request->obj_request_count++;

	img_request->pending_count++;

	list_add_tail(&obj_request->links, &img_request->obj_requests);

	dout("%s: img %p obj %p w=%u\n", __func__, img_request, obj_request,

		obj_request->which);
@@ -1451,10 +1453,6 @@ static void rbd_obj_request_submit(struct rbd_obj_request *obj_request) 
	dout("%s %p object_no %016llx %llu~%llu osd_req %p\n", __func__,

	     obj_request, obj_request->object_no, obj_request->offset,

	     obj_request->length, osd_req);

	if (obj_request_img_data_test(obj_request)) {

		WARN_ON(obj_request->callback != rbd_img_obj_callback);

		rbd_img_request_get(obj_request->img_request);

	}

	ceph_osdc_start_request(osd_req->r_osdc, osd_req, false);

}
@@ -2236,8 +2234,6 @@ static void rbd_img_request_submit(struct rbd_img_request *img_request) 
	rbd_img_request_put(img_request);

}



static void rbd_img_end_child_request(struct rbd_img_request *img_req);



static int rbd_obj_read_from_parent(struct rbd_obj_request *obj_req,

				    u64 img_offset, u32 bytes)

{
@@ -2249,8 +2245,6 @@ static int rbd_obj_read_from_parent(struct rbd_obj_request *obj_req, 
	if (!child_img_req)

		return -ENOMEM;



	child_img_req->callback = rbd_img_end_child_request;



	if (!rbd_img_is_write(img_req)) {

		switch (obj_req->type) {

		case OBJ_REQUEST_BIO:
@@ -2386,8 +2380,6 @@ static int rbd_obj_issue_copyup(struct rbd_obj_request *obj_req, u32 bytes) 
	}



	rbd_obj_request_submit(obj_req);

	/* FIXME: in lieu of rbd_img_obj_callback() */

	rbd_img_request_put(obj_req->img_request);

	return 0;

}
@@ -2540,6 +2532,29 @@ static bool __rbd_obj_handle_request(struct rbd_obj_request *obj_req) 
	}

}



static void rbd_obj_end_request(struct rbd_obj_request *obj_req)

{

	struct rbd_img_request *img_req = obj_req->img_request;



	rbd_assert((!obj_req->result &&

		    obj_req->xferred == obj_req->length) ||

		   (obj_req->result < 0 && !obj_req->xferred));

	if (!obj_req->result) {

		img_req->xferred += obj_req->xferred;

		return;

	}



	rbd_warn(img_req->rbd_dev,

		 "%s at objno %llu %llu~%llu result %d xferred %llu",

		 obj_op_name(img_req->op_type), obj_req->object_no,

		 obj_req->offset, obj_req->length, obj_req->result,

		 obj_req->xferred);

	if (!img_req->result) {

		img_req->result = obj_req->result;

		img_req->xferred = 0;

	}

}



static void rbd_img_end_child_request(struct rbd_img_request *img_req)

{

	struct rbd_obj_request *obj_req = img_req->obj_request;
@@ -2549,17 +2564,44 @@ static void rbd_img_end_child_request(struct rbd_img_request *img_req) 
	obj_req->result = img_req->result;

	obj_req->xferred = img_req->xferred;

	rbd_img_request_put(img_req);

}



	rbd_obj_handle_request(obj_req);

static void rbd_img_end_request(struct rbd_img_request *img_req)

{

	rbd_assert(!test_bit(IMG_REQ_CHILD, &img_req->flags));

	rbd_assert((!img_req->result &&

		    img_req->xferred == blk_rq_bytes(img_req->rq)) ||

		   (img_req->result < 0 && !img_req->xferred));



	blk_mq_end_request(img_req->rq,

			   errno_to_blk_status(img_req->result));

	rbd_img_request_put(img_req);

}



static void rbd_obj_handle_request(struct rbd_obj_request *obj_req)

{

	struct rbd_img_request *img_req;



again:

	if (!__rbd_obj_handle_request(obj_req))

		return;



	obj_request_done_set(obj_req);

	rbd_obj_request_complete(obj_req);

	img_req = obj_req->img_request;

	spin_lock(&img_req->completion_lock);

	rbd_obj_end_request(obj_req);

	rbd_assert(img_req->pending_count);

	if (--img_req->pending_count) {

		spin_unlock(&img_req->completion_lock);

		return;

	}



	spin_unlock(&img_req->completion_lock);

	if (test_bit(IMG_REQ_CHILD, &img_req->flags)) {

		obj_req = img_req->obj_request;

		rbd_img_end_child_request(img_req);

		goto again;

	}

	rbd_img_end_request(img_req);

}



static const struct rbd_client_id rbd_empty_cid;