Update create directory to clear cluster when directory is created

[henrikstengaard]

I have been using DiscUtils for many years with great success and I have recently experienced an issue with fat filesystem library where creating a new directory in root directory of a FAT32 formatted partition would contain existing directories and files with garbled filename characters.

After a lot of testing, I discovered the reason for the newly created directory already contained directories and files with garbled filename characters was caused by clusters contained data from a non-valid FAT32 filesystem structure, which are interpreted as directories and files by DiscUtils fat file system library.

I examined FAT32 clusters when Windows 11 creates a new directory and a file within the directory and noticed that Windows had cleared the cluster with zeroes before creating the cluster for the directory content.

I propose a change to PopulateNewChildDirectory that clears the cluster with zeroes before creating the self and parent referencing directory entries. I also added a test that was first used to verify the issue with existing data can cause a newly created directory to contain existing directories and files with garbled filenames and afterwards use it to fix the issue and verify it works.

[LTRData]

Nice find and thanks a lot for your fix! 👍