feat(btrfs): add online expansion support of btrfs filesystem (#10)

This commit add support for online expansion of btrfs filesystem

Signed-off-by: mittachaitu <[email protected]>

Author: sai chaithanya

pkg/btrfs/btrfs_util.go

@@ -19,9 +19,15 @@ package btrfs
 import (
 	"os/exec"
 
+	"github.com/openebs/lib-csi/pkg/common/errors"
 	"k8s.io/klog"
 )
 
+const (
+	// BTRFS is a command line utility of btrfs filesystem
+	BTRFS = "btrfs"
+)
+
 /*
 * We have to generate a new UUID for the cloned volumes with btrfs filesystem
 * otherwise system will mount the same volume if UUID is same. Here, since cloned
@@ -41,3 +47,22 @@ func GenerateUUID(device string) error {
 	klog.Infof("btrfs: generated UUID for the device %s \n %v", device, string(out))
 	return nil
 }
+
+// ResizeBTRFS will expand btrfs filesystem at given mount point
+func ResizeBTRFS(mountPoint string) error {
+	args := []string{"filesystem", "resize", "max", mountPoint}
+	cmd := exec.Command(BTRFS, args...)
+
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		klog.Errorf(
+			"btrfs utility could not expand btrfs filesystem "+
+				"on mount point: %s cmd: %v error: %s",
+			mountPoint,
+			args,
+			string(out),
+		)
+		return errors.Wrap(err, string(out))
+	}
+	return nil
+}