diff --git a/openstack/blockstorage/v1/snapshots/requests.go b/openstack/blockstorage/v1/snapshots/requests.go
index f54432f..1bc0a14 100644
--- a/openstack/blockstorage/v1/snapshots/requests.go
+++ b/openstack/blockstorage/v1/snapshots/requests.go
@@ -72,7 +72,7 @@
 	_, res.Err = perigee.Request("POST", createURL(client), perigee.Options{
 		MoreHeaders: client.Provider.AuthenticatedHeaders(),
 		OkCodes:     []int{200, 201},
-		ReqBody:     reqBody,
+		ReqBody:     &reqBody,
 		Results:     &res.Resp,
 	})
 	return res
@@ -102,7 +102,7 @@
 // ListOptsBuilder allows extensions to add additional parameters to the List
 // request.
 type ListOptsBuilder interface {
-	ToVolumeListParams() (string, error)
+	ToSnapshotListString() (string, error)
 }
 
 // ListOpts hold options for listing Snapshots. It is passed to the
@@ -113,8 +113,8 @@
 	VolumeID string `q:"volume_id"`
 }
 
-// ToVolumeListParams formats a ListOpts into a query string.
-func (opts ListOpts) ToVolumeListParams() (string, error) {
+// ToSnapshotListString formats a ListOpts into a query string.
+func (opts ListOpts) ToSnapshotListString() (string, error) {
 	q, err := gophercloud.BuildQueryString(opts)
 	if err != nil {
 		return "", err
@@ -127,7 +127,7 @@
 func List(client *gophercloud.ServiceClient, opts ListOptsBuilder) pagination.Pager {
 	url := listURL(client)
 	if opts != nil {
-		query, err := opts.ToVolumeListParams()
+		query, err := opts.ToSnapshotListString()
 		if err != nil {
 			return pagination.Pager{Err: err}
 		}
@@ -180,7 +180,7 @@
 	_, res.Err = perigee.Request("PUT", updateMetadataURL(client, id), perigee.Options{
 		MoreHeaders: client.Provider.AuthenticatedHeaders(),
 		OkCodes:     []int{200},
-		ReqBody:     reqBody,
+		ReqBody:     &reqBody,
 		Results:     &res.Resp,
 	})
 	return res
diff --git a/openstack/blockstorage/v1/volumes/requests.go b/openstack/blockstorage/v1/volumes/requests.go
index dc04732..f46b2b6 100644
--- a/openstack/blockstorage/v1/volumes/requests.go
+++ b/openstack/blockstorage/v1/volumes/requests.go
@@ -87,7 +87,7 @@
 
 	_, res.Err = perigee.Request("POST", createURL(client), perigee.Options{
 		MoreHeaders: client.Provider.AuthenticatedHeaders(),
-		ReqBody:     reqBody,
+		ReqBody:     &reqBody,
 		Results:     &res.Resp,
 		OkCodes:     []int{200, 201},
 	})
@@ -118,7 +118,7 @@
 // ListOptsBuilder allows extensions to add additional parameters to the List
 // request.
 type ListOptsBuilder interface {
-	ToVolumeListParams() (string, error)
+	ToVolumeListString() (string, error)
 }
 
 // ListOpts holds options for listing Volumes. It is passed to the volumes.List
@@ -134,8 +134,8 @@
 	Status string `q:"status"`
 }
 
-// ToVolumeListParams formats a ListOpts into a query string.
-func (opts ListOpts) ToVolumeListParams() (string, error) {
+// ToVolumeListString formats a ListOpts into a query string.
+func (opts ListOpts) ToVolumeListString() (string, error) {
 	q, err := gophercloud.BuildQueryString(opts)
 	if err != nil {
 		return "", err
@@ -147,7 +147,7 @@
 func List(client *gophercloud.ServiceClient, opts ListOptsBuilder) pagination.Pager {
 	url := listURL(client)
 	if opts != nil {
-		query, err := opts.ToVolumeListParams()
+		query, err := opts.ToVolumeListString()
 		if err != nil {
 			return pagination.Pager{Err: err}
 		}
@@ -197,7 +197,7 @@
 
 // Update will update the Volume with provided information. To extract the updated
 // Volume from the response, call the Extract method on the UpdateResult.
-func Update(client *gophercloud.ServiceClient, id string, opts *UpdateOpts) UpdateResult {
+func Update(client *gophercloud.ServiceClient, id string, opts UpdateOptsBuilder) UpdateResult {
 	var res UpdateResult
 
 	reqBody, err := opts.ToVolumeUpdateMap()
@@ -209,7 +209,7 @@
 	_, res.Err = perigee.Request("PUT", updateURL(client, id), perigee.Options{
 		MoreHeaders: client.Provider.AuthenticatedHeaders(),
 		OkCodes:     []int{200},
-		ReqBody:     reqBody,
+		ReqBody:     &reqBody,
 		Results:     &res.Resp,
 	})
 	return res
diff --git a/openstack/blockstorage/v1/volumetypes/requests.go b/openstack/blockstorage/v1/volumetypes/requests.go
index ff71de1..d4f880f 100644
--- a/openstack/blockstorage/v1/volumetypes/requests.go
+++ b/openstack/blockstorage/v1/volumetypes/requests.go
@@ -9,7 +9,7 @@
 // CreateOptsBuilder allows extensions to add additional parameters to the
 // Create request.
 type CreateOptsBuilder interface {
-	ToVolumeTypeCreateMap() map[string]interface{}
+	ToVolumeTypeCreateMap() (map[string]interface{}, error)
 }
 
 // CreateOpts are options for creating a volume type.
@@ -21,7 +21,7 @@
 }
 
 // ToVolumeTypeCreateMap casts a CreateOpts struct to a map.
-func (opts CreateOpts) ToVolumeTypeCreateMap() map[string]interface{} {
+func (opts CreateOpts) ToVolumeTypeCreateMap() (map[string]interface{}, error) {
 	vt := make(map[string]interface{})
 
 	if opts.ExtraSpecs != nil {
@@ -31,17 +31,24 @@
 		vt["name"] = opts.Name
 	}
 
-	return map[string]interface{}{"volume_type": vt}
+	return map[string]interface{}{"volume_type": vt}, nil
 }
 
 // Create will create a new volume. To extract the created volume type object,
 // call the Extract method on the CreateResult.
 func Create(client *gophercloud.ServiceClient, opts CreateOptsBuilder) CreateResult {
 	var res CreateResult
+
+	reqBody, err := opts.ToVolumeTypeCreateMap()
+	if err != nil {
+		res.Err = err
+		return res
+	}
+
 	_, res.Err = perigee.Request("POST", createURL(client), perigee.Options{
 		MoreHeaders: client.Provider.AuthenticatedHeaders(),
 		OkCodes:     []int{200, 201},
-		ReqBody:     opts.ToVolumeTypeCreateMap(),
+		ReqBody:     &reqBody,
 		Results:     &res.Resp,
 	})
 	return res