NAS-139069 Wipe disk writes ASCII 0 instead of bytes 0

[ryd994]

In TrueNAS Scale, wipe the disk using Storage -> Disks -> Wipe -> Quick or Full with zeros. After that, the disk is expected to be wiped with null bytes (numeric value of 0).

However, the disk is filled by 0x30 instead of 0x0:

root@nas[~]# head -c 16 /dev/sdj | hexdump
0000000 3030 3030 3030 3030 3030 3030 3030 3030
0000010

0x30 is ASCII character '0'.

While ASCII character '0' also serves the purpose of destroying the data on disk, it does not match the description in UI and the typical expectation.

The problem is at

middleware/src/middlewared/middlewared/plugins/disk_/wipe.py

Line 78 in 6c6e2c2

to_write = b'0' * CHUNK

It should use b'\0' instead of b'0'

A similar bug exists when expanding partition:

middleware/src/middlewared/middlewared/plugins/disk_/wipe.py

Line 78 in 6c6e2c2

to_write = b'0' * CHUNK

[ryd994]

Jira item: https://ixsystems.atlassian.net/browse/NAS-139069

[themylogin]

@yocalebo I think we should merge this :)

[ryd994]

@themylogin Sorry for not knowing the right procedure. This is the first time I contributing to truenas. What can I do to help this PR merge?