Code review comment for ~redriver/cloud-init:frbsd-azure-branch

> > Hi,
> >
> > I have been doing some testing on FreeBSD.
> >
> > The current growpart seems to work fine with FreeBSD 11.0 with GPT/UFS - the
> > partition gets resized. The issue is with filesystem resize in resizefs. Its
> a
> > simple fix, before you can modify the MBR you must first set
> > kern.geom.debugflags=16, then when calling growfs you must pass the '-y'
> flag.
> > You should then set debugflags back to it's original value.
> >
> > Basically this, I did a quick hack to test and seems ok:
> >
> > current_debugflags = sysctl -n kern.geom.debugflags
> > sysctl kern.geom.debugflags=16
> > growfs -y /dev/vtbd0p2
> > sysctl kern.geom.debugflags=current_debugflags
> My problem is growfs always reports error since the disk is already full
> expanded.
>
> # growfs -y /dev/da0p2
> growfs: requested size 28GB is not larger than the current filesystem size
> 28GB
> # echo $?
> 1
>
> My disk is formatted to be UFS:
> # gpart show
> => 40 62914480 da0 GPT (30G)
> 40 1024 1 freebsd-boot (512K)
> 1064 58719232 2 freebsd-ufs (28G)
> 58720296 3145728 3 freebsd-swap (1.5G)
> 61866024 1048496 - free - (512M)
>
> => 63 146800577 da1 MBR (70G)
> 63 1985 - free - (993K)
> 2048 146796544 1 ntfs (70G)
> 146798592 2048 - free - (1.0M)

Not sure what the most elegant solution would be to avoid exit(1) when there is nothing to do...

Just thinking out loud here:

1.
Can resizefs be called to ignore exit status 1? Could be dangerous?

2.
Is there a way to pass back from growpart to see if gpart size did anything, if so then run growfs?

3.
You could do a dry run first and check the exit status before continuing:
# growfs -N -y /dev/da0p2

4.
Could we look at the current size of the file system and compare to gpart, (there is probably a better way to get the fs size):

# dumpfs -m /
# newfs command for / (/dev/da0p2)
newfs -O 2 -U -a 4 -b 32768 -d 32768 -e 4096 -f 4096 -g 16384 -h 64 -i 8192 -j -k 5240 -m 8 -o time -s 83885872 /dev/da0p2

Grab -s <size> round it and compare against

# gpart show
=> 40 83886000 da0 MBR (466G)
         40 128 1 freebsd-boot (64K)
        168 83886000 2 freebsd-ufs (40.0G)