Re: [PATCH] btrfs: disable zstd support for i386-pc

[Daniel Kiper]

On Thu, Nov 14, 2019 at 09:53:54AM +0000, Michael Chang wrote:
> On Wed, Nov 13, 2019 at 12:00:50PM +0100, Daniel Kiper wrote:
> > On Thu, Nov 07, 2019 at 12:52:35PM +0100, Daniel Kiper wrote:
> > > On Wed, Nov 06, 2019 at 11:15:04AM -0800, Vladimir 'phcoder' Serbinenko 
> > > wrote:
> > > > Please don't do it this way. The right solution is to move it to 
> > > > separate
> > > > module and include zstd module when needed. Not everybody uses btrfs
> > > > embedded area. I recommend not to use it. Using mbr gap or BBP is the
> > > > recommended way.
> > >
> > > I will put the cat among the pigeons. Maybe we should finally stop
> > > pretending that the GRUB supports small MBR gaps. Otherwise we will
> > > be fighting with such issues endlessly.
> >
> > Bumping the thread... Nobody objects? Hmmm...
>
> I don't think we are able to give up MBR gap support, simply because no
> other way out in creating the area for bootloader embedding. However we

Nope, I do not propose that...

> should consider to correct this claim in manual.
>
>  "You must ensure that the first partition starts at least 31 KiB (63
>  sectors) from the start of the disk"
>
> to reflect the fact that 31 KiB is no longer applicable and the ideal
> size should be above 1MB (or such). You should go check with your disk
> tools to find the suitable parameter to fulfill the requirement, for eg,
> the partition alignment would mostly affect this.

Exactly! However, there are some legacy systems which do not boot if MBR
gap does not end at 63 sectors boundary. Hence, maybe we should suggest
chainloading, using e.g. SYSLINUX, in a such cases. Anyway, may I ask
you to prepare a patch for GRUB manual which describes the problem?

Daniel