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Commit a9b67e69 authored by Ilya Dryomov's avatar Ilya Dryomov
Browse files

rbd: replace obj_req->tried_parent with obj_req->read_state 



Make rbd_obj_handle_read() look like a state machine and get rid of
the necessity to patch result in rbd_obj_handle_request(), completing
the removal of obj_req->xferred and img_req->xferred.

Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
Reviewed-by: default avatarDongsheng Yang <dongsheng.yang@easystack.cn>
parent 54ab3b24

drivers/block/rbd.c

+46 −36
Original line number Diff line number Diff line
@@ -219,6 +219,11 @@ enum obj_operation_type { 
	OBJ_OP_ZEROOUT,

};



enum rbd_obj_read_state {

	RBD_OBJ_READ_OBJECT = 1,

	RBD_OBJ_READ_PARENT,

};



/*

 * Writes go through the following state machine to deal with

 * layering:
@@ -255,7 +260,7 @@ enum rbd_obj_write_state { 
struct rbd_obj_request {

	struct ceph_object_extent ex;

	union {

		bool			tried_parent;	/* for reads */

		enum rbd_obj_read_state	 read_state;	/* for reads */

		enum rbd_obj_write_state write_state;	/* for writes */

	};
@@ -1794,6 +1799,7 @@ static int rbd_obj_setup_read(struct rbd_obj_request *obj_req) 
	rbd_osd_req_setup_data(obj_req, 0);



	rbd_osd_req_format_read(obj_req);

	obj_req->read_state = RBD_OBJ_READ_OBJECT;

	return 0;

}
@@ -2402,22 +2408,22 @@ static bool rbd_obj_handle_read(struct rbd_obj_request *obj_req, int *result) 
	struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;

	int ret;



	if (*result == -ENOENT &&

	    rbd_dev->parent_overlap && !obj_req->tried_parent) {

	switch (obj_req->read_state) {

	case RBD_OBJ_READ_OBJECT:

		if (*result == -ENOENT && rbd_dev->parent_overlap) {

			/* reverse map this object extent onto the parent */

			ret = rbd_obj_calc_img_extents(obj_req, false);

			if (ret) {

				*result = ret;

				return true;

			}



			if (obj_req->num_img_extents) {

			obj_req->tried_parent = true;

				ret = rbd_obj_read_from_parent(obj_req);

				if (ret) {

					*result = ret;

					return true;

				}

				obj_req->read_state = RBD_OBJ_READ_PARENT;

				return false;

			}

		}
@@ -2438,8 +2444,12 @@ static bool rbd_obj_handle_read(struct rbd_obj_request *obj_req, int *result) 
				rbd_assert(*result == obj_req->ex.oe_len);

			*result = 0;

		}



		return true;

	case RBD_OBJ_READ_PARENT:

		return true;

	default:

		BUG();

	}

}



/*
@@ -2658,11 +2668,11 @@ static bool rbd_obj_handle_write(struct rbd_obj_request *obj_req, int *result) 
	case RBD_OBJ_WRITE_COPYUP_OPS:

		return true;

	case RBD_OBJ_WRITE_READ_FROM_PARENT:

		if (*result < 0)

		if (*result)

			return true;



		rbd_assert(*result);

		ret = rbd_obj_issue_copyup(obj_req, *result);

		ret = rbd_obj_issue_copyup(obj_req,

					   rbd_obj_img_extents_bytes(obj_req));

		if (ret) {

			*result = ret;

			return true;
@@ -2757,7 +2767,7 @@ static void rbd_obj_handle_request(struct rbd_obj_request *obj_req, int result) 
	rbd_assert(img_req->result <= 0);

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

		obj_req = img_req->obj_request;

		result = img_req->result ?: rbd_obj_img_extents_bytes(obj_req);

		result = img_req->result;

		rbd_img_request_put(img_req);

		goto again;

	}