fix(zfspv): rounding off the volume size to Gi and Mi

ZFS does not create the zvol if volume size is not multiple of
the volblocksize. There are use cases where customer will create
a PVC with size as 5G, which will be 5 * 1000 * 1000 * 1000 bytes
and this is not the multiple of default volblocksize 8k.

In ZFS, volblocksize and recordsize must be power of 2 from 512B to 1M,
so keeping the size in the form of Gi or Mi should be
sufficient to make volsize multiple of volblocksize/recordsize.

Signed-off-by: Pawan <pawan@mayadata.io>

changelogs/unreleased/191-pawanpraka1

@@ -0,0 +1 @@
+rounding off the volume size to Gi and Mi

pkg/driver/controller.go

@@ -37,6 +37,12 @@ import (
 	zfs "github.com/openebs/zfs-localpv/pkg/zfs"
 )
 
+// size constants
+const (
+	Mi = 1024 * 1024
+	Gi = 1024 * 1024 * 1024
+)
+
 // controller is the server implementation
 // for CSI Controller
 type controller struct {
@@ -75,10 +81,26 @@ func sendEventOrIgnore(pvcName, pvName, capacity, stgType, method string) {
 	}
 }
 
+// getRoundedCapacity rounds the capacity on 1024 base
+func getRoundedCapacity(size int64) int64 {
+
+	/*
+	 * volblocksize and recordsize must be power of 2 from 512B to 1M
+	 * so keeping the size in the form of Gi or Mi should be
+	 * sufficient to make volsize multiple of volblocksize/recordsize.
+	 */
+	if size > Gi {
+		return ((size + Gi - 1) / Gi) * Gi
+	}
+
+	// Keeping minimum allocatable size as 1Mi (1024 * 1024)
+	return ((size + Mi - 1) / Mi) * Mi
+}
+
 // CreateZFSVolume create new zfs volume from csi volume request
 func CreateZFSVolume(req *csi.CreateVolumeRequest) (string, error) {
 	volName := req.GetName()
-	size := req.GetCapacityRange().RequiredBytes
+	size := getRoundedCapacity(req.GetCapacityRange().RequiredBytes)
 
 	// parameter keys may be mistyped from the CRD specification when declaring
 	// the storageclass, which kubectl validation will not catch. Because ZFS
@@ -148,7 +170,7 @@ func CreateZFSClone(req *csi.CreateVolumeRequest, snapshot string) (string, erro
 	parameters := req.GetParameters()
 	// lower case keys, cf CreateZFSVolume()
 	pool := helpers.GetInsensitiveParameter(&parameters, "poolname")
-	size := req.GetCapacityRange().RequiredBytes
+	size := getRoundedCapacity(req.GetCapacityRange().RequiredBytes)
 	volsize := strconv.FormatInt(int64(size), 10)
 
 	snapshotID := strings.Split(snapshot, "@")
@@ -208,7 +230,7 @@ func (cs *controller) CreateVolume(
 	parameters := req.GetParameters()
 	// lower case keys, cf CreateZFSVolume()
 	pool := helpers.GetInsensitiveParameter(&parameters, "poolname")
-	size := req.GetCapacityRange().RequiredBytes
+	size := getRoundedCapacity(req.GetCapacityRange().RequiredBytes)
 	contentSource := req.GetVolumeContentSource()
 	pvcName := helpers.GetInsensitiveParameter(&parameters, "csi.storage.k8s.io/pvc/name")
 
@@ -325,7 +347,8 @@ func (cs *controller) ControllerExpandVolume(
 	req *csi.ControllerExpandVolumeRequest,
 ) (*csi.ControllerExpandVolumeResponse, error) {
 
-	updatedSize := req.GetCapacityRange().GetRequiredBytes()
+	/* round off the new size */
+	updatedSize := getRoundedCapacity(req.GetCapacityRange().GetRequiredBytes())
 
 	vol, err := zfs.GetZFSVolume(req.VolumeId)
 	if err != nil {