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Commit 6484cbe9 authored by Ilya Dryomov's avatar Ilya Dryomov
Browse files

rbd: handle DISCARD and WRITE_ZEROES separately 



With discard_zeroes_data gone in commit 48920ff2 ("block: remove
the discard_zeroes_data flag"), continuing to provide this guarantee is
pointless: applications can't query it and discards can only be used
for deallocating.

Add OBJ_OP_ZEROOUT and move the existing logic under it.  As the first
step to divorcing OBJ_OP_DISCARD, stop worrying about copyups but keep
special casing whole-object layered discards.

Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
Reviewed-by: default avatarJason Dillaman <dillaman@redhat.com>
parent fd7e3f0d

drivers/block/rbd.c

+51 −10
Original line number Diff line number Diff line
@@ -214,6 +214,7 @@ enum obj_operation_type { 
	OBJ_OP_READ = 1,

	OBJ_OP_WRITE,

	OBJ_OP_DISCARD,

	OBJ_OP_ZEROOUT,

};



/*
@@ -857,6 +858,8 @@ static char* obj_op_name(enum obj_operation_type op_type) 
		return "write";

	case OBJ_OP_DISCARD:

		return "discard";

	case OBJ_OP_ZEROOUT:

		return "zeroout";

	default:

		return "???";

	}
@@ -1419,6 +1422,7 @@ static bool rbd_img_is_write(struct rbd_img_request *img_req) 
		return false;

	case OBJ_OP_WRITE:

	case OBJ_OP_DISCARD:

	case OBJ_OP_ZEROOUT:

		return true;

	default:

		BUG();
@@ -1841,7 +1845,40 @@ static int rbd_obj_setup_write(struct rbd_obj_request *obj_req) 
	return 0;

}



static void __rbd_obj_setup_discard(struct rbd_obj_request *obj_req,

static u16 truncate_or_zero_opcode(struct rbd_obj_request *obj_req)

{

	return rbd_obj_is_tail(obj_req) ? CEPH_OSD_OP_TRUNCATE :

					  CEPH_OSD_OP_ZERO;

}



static int rbd_obj_setup_discard(struct rbd_obj_request *obj_req)

{

	int ret;



	/* reverse map the entire object onto the parent */

	ret = rbd_obj_calc_img_extents(obj_req, true);

	if (ret)

		return ret;



	obj_req->osd_req = rbd_osd_req_create(obj_req, 1);

	if (!obj_req->osd_req)

		return -ENOMEM;



	if (rbd_obj_is_entire(obj_req) && !obj_req->num_img_extents) {

		osd_req_op_init(obj_req->osd_req, 0, CEPH_OSD_OP_DELETE, 0);

	} else {

		osd_req_op_extent_init(obj_req->osd_req, 0,

				       truncate_or_zero_opcode(obj_req),

				       obj_req->ex.oe_off, obj_req->ex.oe_len,

				       0, 0);

	}



	obj_req->write_state = RBD_OBJ_WRITE_FLAT;

	rbd_osd_req_format_write(obj_req);

	return 0;

}



static void __rbd_obj_setup_zeroout(struct rbd_obj_request *obj_req,

				    unsigned int which)

{

	u16 opcode;
@@ -1856,10 +1893,8 @@ static void __rbd_obj_setup_discard(struct rbd_obj_request *obj_req, 
					CEPH_OSD_OP_DELETE, 0);

			opcode = 0;

		}

	} else if (rbd_obj_is_tail(obj_req)) {

		opcode = CEPH_OSD_OP_TRUNCATE;

	} else {

		opcode = CEPH_OSD_OP_ZERO;

		opcode = truncate_or_zero_opcode(obj_req);

	}



	if (opcode)
@@ -1871,7 +1906,7 @@ static void __rbd_obj_setup_discard(struct rbd_obj_request *obj_req, 
	rbd_osd_req_format_write(obj_req);

}



static int rbd_obj_setup_discard(struct rbd_obj_request *obj_req)

static int rbd_obj_setup_zeroout(struct rbd_obj_request *obj_req)

{

	unsigned int num_osd_ops, which = 0;

	int ret;
@@ -1907,7 +1942,7 @@ static int rbd_obj_setup_discard(struct rbd_obj_request *obj_req) 
			return ret;

	}



	__rbd_obj_setup_discard(obj_req, which);

	__rbd_obj_setup_zeroout(obj_req, which);

	return 0;

}
@@ -1932,6 +1967,9 @@ static int __rbd_img_fill_request(struct rbd_img_request *img_req) 
		case OBJ_OP_DISCARD:

			ret = rbd_obj_setup_discard(obj_req);

			break;

		case OBJ_OP_ZEROOUT:

			ret = rbd_obj_setup_zeroout(obj_req);

			break;

		default:

			rbd_assert(0);

		}
@@ -2392,9 +2430,9 @@ static int rbd_obj_issue_copyup(struct rbd_obj_request *obj_req, u32 bytes) 
	case OBJ_OP_WRITE:

		__rbd_obj_setup_write(obj_req, 1);

		break;

	case OBJ_OP_DISCARD:

	case OBJ_OP_ZEROOUT:

		rbd_assert(!rbd_obj_is_entire(obj_req));

		__rbd_obj_setup_discard(obj_req, 1);

		__rbd_obj_setup_zeroout(obj_req, 1);

		break;

	default:

		rbd_assert(0);
@@ -2524,6 +2562,7 @@ static bool __rbd_obj_handle_request(struct rbd_obj_request *obj_req) 
	case OBJ_OP_WRITE:

		return rbd_obj_handle_write(obj_req);

	case OBJ_OP_DISCARD:

	case OBJ_OP_ZEROOUT:

		if (rbd_obj_handle_write(obj_req)) {

			/*

			 * Hide -ENOENT from delete/truncate/zero -- discarding
@@ -3636,9 +3675,11 @@ static void rbd_queue_workfn(struct work_struct *work) 


	switch (req_op(rq)) {

	case REQ_OP_DISCARD:

	case REQ_OP_WRITE_ZEROES:

		op_type = OBJ_OP_DISCARD;

		break;

	case REQ_OP_WRITE_ZEROES:

		op_type = OBJ_OP_ZEROOUT;

		break;

	case REQ_OP_WRITE:

		op_type = OBJ_OP_WRITE;

		break;
@@ -3718,7 +3759,7 @@ static void rbd_queue_workfn(struct work_struct *work) 
	img_request->rq = rq;

	snapc = NULL; /* img_request consumes a ref */



	if (op_type == OBJ_OP_DISCARD)

	if (op_type == OBJ_OP_DISCARD || op_type == OBJ_OP_ZEROOUT)

		result = rbd_img_fill_nodata(img_request, offset, length);

	else

		result = rbd_img_fill_from_bio(img_request, offset, length,