rbd: switch rbd_obj_method_sync() to ceph_osdc_call()

As explained in the previous commit, rbd_obj_request machinery (and
rbd_osd_req_create() in particular) shouldn't be used for working with
metadata objects.

Switch to the recently added ceph_osdc_call().  It assumes single pages
for outbound and inbound buffers, but that's OK - none of the callers
need more than that.  These pages need to be allocated (messenger is in
dire need of proper iterator interface!), but we are swapping for
pages[] and pagelist allocations in the existing code.

Kill class_name argument - all rbd methods are under "rbd".
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>
Reviewed-by: NJason Dillaman <dillaman@redhat.com>

drivers/block/rbd.c

@@ -3971,17 +3971,17 @@ static void rbd_reregister_watch(struct work_struct *work)
  * returned in the outbound buffer, or a negative error code.
  */
 static int rbd_obj_method_sync(struct rbd_device *rbd_dev,
-			     const char *object_name,
-			     const char *class_name,
+			     struct ceph_object_id *oid,
+			     struct ceph_object_locator *oloc,
 			     const char *method_name,
 			     const void *outbound,
 			     size_t outbound_size,
 			     void *inbound,
 			     size_t inbound_size)
 {
-	struct rbd_obj_request *obj_request;
-	struct page **pages;
-	u32 page_count;
+	struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
+	struct page *req_page = NULL;
+	struct page *reply_page;
 	int ret;
 
 	/*
@@ -3991,61 +3991,35 @@ static int rbd_obj_method_sync(struct rbd_device *rbd_dev,
 	 * method.  Currently if this is present it will be a
 	 * snapshot id.
 	 */
-	page_count = (u32)calc_pages_for(0, inbound_size);
-	pages = ceph_alloc_page_vector(page_count, GFP_KERNEL);
-	if (IS_ERR(pages))
-		return PTR_ERR(pages);
+	if (outbound) {
+		if (outbound_size > PAGE_SIZE)
+			return -E2BIG;
 
-	ret = -ENOMEM;
-	obj_request = rbd_obj_request_create(object_name, 0, inbound_size,
-							OBJ_REQUEST_PAGES);
-	if (!obj_request)
-		goto out;
-
-	obj_request->pages = pages;
-	obj_request->page_count = page_count;
-
-	obj_request->osd_req = rbd_osd_req_create(rbd_dev, OBJ_OP_READ, 1,
-						  obj_request);
-	if (!obj_request->osd_req)
-		goto out;
-
-	osd_req_op_cls_init(obj_request->osd_req, 0, CEPH_OSD_OP_CALL,
-					class_name, method_name);
-	if (outbound_size) {
-		struct ceph_pagelist *pagelist;
-
-		pagelist = kmalloc(sizeof (*pagelist), GFP_NOFS);
-		if (!pagelist)
-			goto out;
+		req_page = alloc_page(GFP_KERNEL);
+		if (!req_page)
+			return -ENOMEM;
 
-		ceph_pagelist_init(pagelist);
-		ceph_pagelist_append(pagelist, outbound, outbound_size);
-		osd_req_op_cls_request_data_pagelist(obj_request->osd_req, 0,
-						pagelist);
+		memcpy(page_address(req_page), outbound, outbound_size);
 	}
-	osd_req_op_cls_response_data_pages(obj_request->osd_req, 0,
-					obj_request->pages, inbound_size,
-					0, false, false);
 
-	rbd_obj_request_submit(obj_request);
-	ret = rbd_obj_request_wait(obj_request);
-	if (ret)
-		goto out;
-
-	ret = obj_request->result;
-	if (ret < 0)
-		goto out;
+	reply_page = alloc_page(GFP_KERNEL);
+	if (!reply_page) {
+		if (req_page)
+			__free_page(req_page);
+		return -ENOMEM;
+	}
 
-	rbd_assert(obj_request->xferred < (u64)INT_MAX);
-	ret = (int)obj_request->xferred;
-	ceph_copy_from_page_vector(pages, inbound, 0, obj_request->xferred);
-out:
-	if (obj_request)
-		rbd_obj_request_put(obj_request);
-	else
-		ceph_release_page_vector(pages, page_count);
+	ret = ceph_osdc_call(osdc, oid, oloc, RBD_DRV_NAME, method_name,
+			     CEPH_OSD_FLAG_READ, req_page, outbound_size,
+			     reply_page, &inbound_size);
+	if (!ret) {
+		memcpy(inbound, page_address(reply_page), inbound_size);
+		ret = inbound_size;
+	}
 
+	if (req_page)
+		__free_page(req_page);
+	__free_page(reply_page);
 	return ret;
 }
 
@@ -4939,10 +4913,10 @@ static int _rbd_dev_v2_snap_size(struct rbd_device *rbd_dev, u64 snap_id,
 		__le64 size;
 	} __attribute__ ((packed)) size_buf = { 0 };
 
-	ret = rbd_obj_method_sync(rbd_dev, rbd_dev->header_oid.name,
-				"rbd", "get_size",
-				&snapid, sizeof (snapid),
-				&size_buf, sizeof (size_buf));
+	ret = rbd_obj_method_sync(rbd_dev, &rbd_dev->header_oid,
+				  &rbd_dev->header_oloc, "get_size",
+				  &snapid, sizeof(snapid),
+				  &size_buf, sizeof(size_buf));
 	dout("%s: rbd_obj_method_sync returned %d\n", __func__, ret);
 	if (ret < 0)
 		return ret;
@@ -4979,9 +4953,9 @@ static int rbd_dev_v2_object_prefix(struct rbd_device *rbd_dev)
 	if (!reply_buf)
 		return -ENOMEM;
 
-	ret = rbd_obj_method_sync(rbd_dev, rbd_dev->header_oid.name,
-				"rbd", "get_object_prefix", NULL, 0,
-				reply_buf, RBD_OBJ_PREFIX_LEN_MAX);
+	ret = rbd_obj_method_sync(rbd_dev, &rbd_dev->header_oid,
+				  &rbd_dev->header_oloc, "get_object_prefix",
+				  NULL, 0, reply_buf, RBD_OBJ_PREFIX_LEN_MAX);
 	dout("%s: rbd_obj_method_sync returned %d\n", __func__, ret);
 	if (ret < 0)
 		goto out;
@@ -5014,10 +4988,10 @@ static int _rbd_dev_v2_snap_features(struct rbd_device *rbd_dev, u64 snap_id,
 	u64 unsup;
 	int ret;
 
-	ret = rbd_obj_method_sync(rbd_dev, rbd_dev->header_oid.name,
-				"rbd", "get_features",
-				&snapid, sizeof (snapid),
-				&features_buf, sizeof (features_buf));
+	ret = rbd_obj_method_sync(rbd_dev, &rbd_dev->header_oid,
+				  &rbd_dev->header_oloc, "get_features",
+				  &snapid, sizeof(snapid),
+				  &features_buf, sizeof(features_buf));
 	dout("%s: rbd_obj_method_sync returned %d\n", __func__, ret);
 	if (ret < 0)
 		return ret;
@@ -5076,10 +5050,9 @@ static int rbd_dev_v2_parent_info(struct rbd_device *rbd_dev)
 	}
 
 	snapid = cpu_to_le64(rbd_dev->spec->snap_id);
-	ret = rbd_obj_method_sync(rbd_dev, rbd_dev->header_oid.name,
-				"rbd", "get_parent",
-				&snapid, sizeof (snapid),
-				reply_buf, size);
+	ret = rbd_obj_method_sync(rbd_dev, &rbd_dev->header_oid,
+				  &rbd_dev->header_oloc, "get_parent",
+				  &snapid, sizeof(snapid), reply_buf, size);
 	dout("%s: rbd_obj_method_sync returned %d\n", __func__, ret);
 	if (ret < 0)
 		goto out_err;
@@ -5179,9 +5152,9 @@ static int rbd_dev_v2_striping_info(struct rbd_device *rbd_dev)
 	u64 stripe_count;
 	int ret;
 
-	ret = rbd_obj_method_sync(rbd_dev, rbd_dev->header_oid.name,
-				"rbd", "get_stripe_unit_count", NULL, 0,
-				(char *)&striping_info_buf, size);
+	ret = rbd_obj_method_sync(rbd_dev, &rbd_dev->header_oid,
+				&rbd_dev->header_oloc, "get_stripe_unit_count",
+				NULL, 0, &striping_info_buf, size);
 	dout("%s: rbd_obj_method_sync returned %d\n", __func__, ret);
 	if (ret < 0)
 		return ret;
@@ -5218,6 +5191,7 @@ static int rbd_dev_v2_striping_info(struct rbd_device *rbd_dev)
 
 static char *rbd_dev_image_name(struct rbd_device *rbd_dev)
 {
+	CEPH_DEFINE_OID_ONSTACK(oid);
 	size_t image_id_size;
 	char *image_id;
 	void *p;
@@ -5245,10 +5219,10 @@ static char *rbd_dev_image_name(struct rbd_device *rbd_dev)
 	if (!reply_buf)
 		goto out;
 
-	ret = rbd_obj_method_sync(rbd_dev, RBD_DIRECTORY,
-				"rbd", "dir_get_name",
-				image_id, image_id_size,
-				reply_buf, size);
+	ceph_oid_printf(&oid, "%s", RBD_DIRECTORY);
+	ret = rbd_obj_method_sync(rbd_dev, &oid, &rbd_dev->header_oloc,
+				  "dir_get_name", image_id, image_id_size,
+				  reply_buf, size);
 	if (ret < 0)
 		goto out;
 	p = reply_buf;
@@ -5427,9 +5401,9 @@ static int rbd_dev_v2_snap_context(struct rbd_device *rbd_dev)
 	if (!reply_buf)
 		return -ENOMEM;
 
-	ret = rbd_obj_method_sync(rbd_dev, rbd_dev->header_oid.name,
-				"rbd", "get_snapcontext", NULL, 0,
-				reply_buf, size);
+	ret = rbd_obj_method_sync(rbd_dev, &rbd_dev->header_oid,
+				  &rbd_dev->header_oloc, "get_snapcontext",
+				  NULL, 0, reply_buf, size);
 	dout("%s: rbd_obj_method_sync returned %d\n", __func__, ret);
 	if (ret < 0)
 		goto out;
@@ -5492,10 +5466,9 @@ static const char *rbd_dev_v2_snap_name(struct rbd_device *rbd_dev,
 		return ERR_PTR(-ENOMEM);
 
 	snapid = cpu_to_le64(snap_id);
-	ret = rbd_obj_method_sync(rbd_dev, rbd_dev->header_oid.name,
-				"rbd", "get_snapshot_name",
-				&snapid, sizeof (snapid),
-				reply_buf, size);
+	ret = rbd_obj_method_sync(rbd_dev, &rbd_dev->header_oid,
+				  &rbd_dev->header_oloc, "get_snapshot_name",
+				  &snapid, sizeof(snapid), reply_buf, size);
 	dout("%s: rbd_obj_method_sync returned %d\n", __func__, ret);
 	if (ret < 0) {
 		snap_name = ERR_PTR(ret);
@@ -5802,7 +5775,7 @@ static int rbd_dev_image_id(struct rbd_device *rbd_dev)
 {
 	int ret;
 	size_t size;
-	char *object_name;
+	CEPH_DEFINE_OID_ONSTACK(oid);
 	void *response;
 	char *image_id;
 
@@ -5822,12 +5795,12 @@ static int rbd_dev_image_id(struct rbd_device *rbd_dev)
 	 * First, see if the format 2 image id file exists, and if
 	 * so, get the image's persistent id from it.
 	 */
-	size = sizeof (RBD_ID_PREFIX) + strlen(rbd_dev->spec->image_name);
-	object_name = kmalloc(size, GFP_NOIO);
-	if (!object_name)
-		return -ENOMEM;
-	sprintf(object_name, "%s%s", RBD_ID_PREFIX, rbd_dev->spec->image_name);
-	dout("rbd id object name is %s\n", object_name);
+	ret = ceph_oid_aprintf(&oid, GFP_KERNEL, "%s%s", RBD_ID_PREFIX,
+			       rbd_dev->spec->image_name);
+	if (ret)
+		return ret;
+
+	dout("rbd id object name is %s\n", oid.name);
 
 	/* Response will be an encoded string, which includes a length */
 
@@ -5840,9 +5813,9 @@ static int rbd_dev_image_id(struct rbd_device *rbd_dev)
 
 	/* If it doesn't exist we'll assume it's a format 1 image */
 
-	ret = rbd_obj_method_sync(rbd_dev, object_name,
-				"rbd", "get_id", NULL, 0,
-				response, RBD_IMAGE_ID_LEN_MAX);
+	ret = rbd_obj_method_sync(rbd_dev, &oid, &rbd_dev->header_oloc,
+				  "get_id", NULL, 0,
+				  response, RBD_IMAGE_ID_LEN_MAX);
 	dout("%s: rbd_obj_method_sync returned %d\n", __func__, ret);
 	if (ret == -ENOENT) {
 		image_id = kstrdup("", GFP_KERNEL);
@@ -5865,8 +5838,7 @@ static int rbd_dev_image_id(struct rbd_device *rbd_dev)
 	}
 out:
 	kfree(response);
-	kfree(object_name);
-
+	ceph_oid_destroy(&oid);
 	return ret;
 }