cephfs: round to cephfs size to multiple of 4Mib

Due to the bug in the df stat we need to round off
the subvolume size to align with 4Mib.

Note:- Minimum supported size in cephcsi is 1Mib,
we dont need to take care of Kib.

fixes #3240

More details at https://github.com/ceph/ceph/pull/46905

Signed-off-by: Madhu Rajanna <madhupr007@gmail.com>

internal/cephfs/controllerserver.go

@@ -277,7 +277,7 @@ func (cs *ControllerServer) CreateVolume(
 	defer volOptions.Destroy()
 
 	if req.GetCapacityRange() != nil {
-		volOptions.Size = util.RoundOffBytes(req.GetCapacityRange().GetRequiredBytes())
+		volOptions.Size = util.RoundOffCephFSVolSize(req.GetCapacityRange().GetRequiredBytes())
 	}
 
 	parentVol, pvID, sID, err := checkContentSource(ctx, req, cr)
@@ -672,7 +672,8 @@ func (cs *ControllerServer) ControllerExpandVolume(
 		return nil, status.Error(codes.InvalidArgument, "cannot expand snapshot-backed volume")
 	}
 
-	RoundOffSize := util.RoundOffBytes(req.GetCapacityRange().GetRequiredBytes())
+	RoundOffSize := util.RoundOffCephFSVolSize(req.GetCapacityRange().GetRequiredBytes())
+
 	volClient := core.NewSubVolume(volOptions.GetConnection(), &volOptions.SubVolume, volOptions.ClusterID)
 	if err = volClient.ResizeVolume(ctx, RoundOffSize); err != nil {
 		log.ErrorLog(ctx, "failed to expand volume %s: %v", fsutil.VolumeID(volIdentifier.FsSubvolName), err)

internal/util/util.go

@@ -58,6 +58,22 @@ func RoundOffBytes(bytes int64) int64 {
 	return num
 }
 
+// RoundOffCephFSVolSize rounds up the bytes to 4MiB if the request is less
+// than 4MiB or if its greater it rounds up to multiple of 4MiB.
+func RoundOffCephFSVolSize(bytes int64) int64 {
+	// Minimum supported size is 1MiB in CephCSI, if the request is <4MiB,
+	// round off to 4MiB.
+	if bytes < helpers.MiB {
+		return 4 * helpers.MiB
+	}
+
+	bytes /= helpers.MiB
+
+	bytes = int64(math.Ceil(float64(bytes)/4) * 4)
+
+	return RoundOffBytes(bytes * helpers.MiB)
+}
+
 // variables which will be set during the build time.
 var (
 	// GitCommit tell the latest git commit image is built from.

internal/util/util_test.go

@@ -352,3 +352,52 @@ func TestCheckKernelSupport(t *testing.T) {
 		}
 	}
 }
+
+func TestRoundOffCephFSVolSize(t *testing.T) {
+	t.Parallel()
+	tests := []struct {
+		name string
+		size int64
+		want int64
+	}{
+		{
+			"1000kiB conversion",
+			1000,
+			4194304, // 4 MiB
+		},
+		{
+			"1MiB conversions",
+			1048576,
+			4194304, // 4 MiB
+		},
+		{
+			"1.5Mib conversion",
+			1677722,
+			4194304, // 4 MiB
+		},
+		{
+			"1023MiB conversion",
+			1072693248,
+			1073741824, // 1024 MiB
+		},
+		{
+			"1.5GiB conversion",
+			1585446912,
+			2147483648, // 2 GiB
+		},
+		{
+			"1555MiB conversion",
+			1630535680,
+			2147483648, // 2 GiB
+		},
+	}
+	for _, tt := range tests {
+		ts := tt
+		t.Run(ts.name, func(t *testing.T) {
+			t.Parallel()
+			if got := RoundOffCephFSVolSize(ts.size); got != ts.want {
+				t.Errorf("RoundOffCephFSVolSize() = %v, want %v", got, ts.want)
+			}
+		})
+	}
+}