A request for unnested UFS implementation in MBR

[Ronald Klop]

On Sat, 07 Jul 2018 07:59:55 +0200, Manish Jain <jude.obscure at yandex.com>  
wrote:

> Hi all,
>
> I am a longtime user of FreeBSD, which now serves as my only OS.
>
> There is one request I wished to make for FreeBSD filesystems. While UFS  
> implementation under GPT is unnested just as Ext2, the MBR  
> implementation of UFS continues to piggyback on an unnecessary nest (in  
> a BSD slice).
>
> Can it not be considered as an alternative to provide a UFS partition  
> (unnested) under MBR too ?
>
> Existing users could continue to use the freebsd::freebsd-ufs scheme,  
> while fresh usage could have the alternative of UFS directly recorded in  
> the MBR.
>
> I should perhaps note that unlike most users who have shifted to GPT of  
> late, I much prefer MBR because 1) the scheme's design by itself keeps  
> the number of slices/partitions in a disk manageable; and 2) I can use  
> the boot0 manager, my favourite boot manager.
>
> Thanks for reading this.
> Manish Jain

Do you mean something like this? Gpart refuses to create a freebsd-ufs  
partition in the MBR part.

# mdconfig -s 512m
md0
# gpart create -s MBR md0
md0 created
# gpart add -t freebsd-ufs -s 256m md0
gpart: Invalid argument
# gpart add -t freebsd-swap -s 256m md0
gpart: Invalid argument

But you can create and newfs other types.

# gpart add -t linux-data -s 256M md0
md0s1 added
# newfs /dev/md0s1
/dev/md0s1: 256.0MB (524288 sectors) block size 32768, fragment size 4096
	using 4 cylinder groups of 64.03MB, 2049 blks, 8320 inodes.
super-block backups (for fsck_ffs -b #) at:
  192, 131328, 262464, 393600

# gpart add -t freebsd md0
md0s2 added
# newfs /dev/md0s2
/dev/md0s2: 256.0MB (524272 sectors) block size 32768, fragment size 4096
	using 4 cylinder groups of 64.00MB, 2048 blks, 8192 inodes.
super-block backups (for fsck_ffs -b #) at:
  192, 131264, 262336, 393408


Interesting. I don't why this is.

Regards,
Ronald.