Fix fallocate issue on cloud-init 19.4 for Fedora 33 cloud images

[Federico Ressi]

Hello all,

I am writing to this list because I found out F33 cloud image cloud init
support for creating swap files looks to be broken probably because of a
known Linux 5.7+ kernel issue [1].

The problem is cloud-init is trying to create a new swap file by using
fallocate command that is not working well (kernel is complaining the file
has holes when executing swapon command just later). The easy workaround
for this issue is to use dd command instead of fallocate command in
cloud-init.

Because I don't know the whole procedure required for submitting a patch I
am writing to you in the hope you can help me in having the F33 cloud image
fixed.
Please find attached to this e-mail the simple fix for cloud init 19.4 I
just wrote. The patch should apply the procedure documented in Fedora docs
[2]

Thank you in advance.
Federico

[1] https://marcelhauri.ch/blog/swapon-swapfile-has-holes/
[2]
https://docs.fedoraproject.org/en-US/Fedora/14/html/Storage_Administratio...