Locking the bootloader does not wipe any data, but when you want to flash it again, you must run fastboot oem unlock again, which will wipe the data. (mobilesyrup.com)
In the command prompt type the command «fastbook oem unlock» (without quotations) and in the confirmation page use the volume rocker to move the option to «Yes» and press the power button to select the option. (bgr.in)
In order to unlock the bootloader, you'll first need to obtain a bootloader unlock code from Huawei, which will be required at the time of executing the fastboot oem unlock command. (xda-developers.com)