fix(probe): close open fd after exclusive open (#450)

NDM was keeping a file descriptor open after an exclusive open, causing other applications to receive a resource busy error.

Signed-off-by: Akhil Mohan <[email protected]>

changelogs/unreleased/450-akhilerm

@@ -0,0 +1 @@
+fix bug of having an open file descriptor in NDM causing applications to receive resource busy error.

cmd/ndm_daemonset/probe/usedbyprobe.go

@@ -200,13 +200,14 @@ func getBlockDeviceZFSPartition(bd blockdevice.BlockDevice) (string, bool) {
 // isBlockDeviceInUseByKernel tries to open the device exclusively to check if the device is
 // being held by some process. eg: If kernel zfs uses the disk, the open will fail
 func isBlockDeviceInUseByKernel(path string) (bool, error) {
-	_, err := os.OpenFile(path, os.O_EXCL, 0444)
+	f, err := os.OpenFile(path, os.O_EXCL, 0444)
 
 	if errors.Is(err, syscall.EBUSY) {
 		return true, nil
 	}
 	if err != nil {
 		return false, err
 	}
+	defer f.Close()
 	return false, nil
 }