Re: kern/42573: DIRBLKSIZ in <ufs/ufs/dir.h> should not beDEV_BSIZE constant

[Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost>]

>  > >  But to make everything fit (eg i386 boot code) the byte alignments
>  > >  cannot change - the label has to remain in bytes 512-1203.
>  > 
>  > Does it? What about "LABELSECTOR" in <machine/disklabel.h>?
>  
>  LABELSECTOR needs to go.

Hmm, how can you fix sys/kern/subr_disk_mbr.c without it?

>  > Shouldn't sys/arch/i386/stand/mbr/mbr.S be sector size aware?
>  I think that code is safe - even though it will read rather more data
>  than expected.
>  What happens later on is a bigger problem.

The problem is that current bootloader code assume sector size is 512.
I wonder if we should keep such assumption even on !512byte/sector disks.

>  > >  (I have a USB memory stick with 2k sectors, the 0x55, 0xaa are in
>  > >  bytes 510 and 511 as usual.)
>  > 
>  > Magic should be at MBR_MAGIC_OFFSET defined in <sys/bootblock.h>
>  > so it doesn't matter of sector size, does it?
>  
>  No - NetBSD doesn't have control over the mbr layout.
>  We have to match what (probably) microsoft does.

Anyway, file a new PR about it. This PR is about DIRBLKSIZ,
just one of a bunch of !512byte/sector problems.
---
Izumi Tsutsui