Re: Patch for 256 disks in 2.4

[Kurt Garloff]

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Hi Pete,

On Mon, Jul 22, 2002 at 04:48:56PM -0400, Pete Zaitcev wrote:
> > From: Kurt Garloff <[e-mail]>
>=20
> > > For those who do not follow, John Cagle allocated 8 more SCSI
> > > disk majors.
> >=20
> > Have those officially been assigned to SCSI disks?
> > So disks 128 -- 255 have majors 128 thr. 135?
>=20
> I do not understand what your problem is. Do you refuse to recognise
> John as the LANANA chair or something?

Strange. I was just asking. Why would you think I would be silly and
refuse to recognize somebody?

> My patch is done in accordance with this:
> http://www.lanana.org/docs/device-list/devices.txt

OK, I should have checked there before asking here, probably.

> > SCSI disks connected. The patch does support up to 160 SD majors,=20
> > though currently, it won't succeed getting more than 132 majors.
>=20
> That's wonderful, but we cannot ship that. There is no userland
> support to create device nodes in dynamic fashion and to ensure
> that they do not conflict.

There will be.

> This is why Arjan filed for and received
> additional majors. Dynamic solutions need some time to float about
> the community, I think.

I don't object to having some more static ones. Fewer users will need
userspace tools for handling the dev nodes then ;-)
And of course, I'll adapt my patch to grab the assigned ones before
the unknown ones ...

> BTW, DASD does the same thing already. I never saw any memo or document
> explaining how to use this capability properly. Perhaps SuSE people
> support it. Kurt, can you tell anything about it?

I don't know much about DASD. They allocate block majors dynamically
starting from 255 backwards as far as I know. So, dev nodes need to
be created dynamically, I guess.

> > Do you have any idea why we can't just sync all mounted filesystems
> > in do_emergency_sync()?
> >  DASD? LVM? EVMS? MD? Loop? NBD? DRBD? What's the rationale=20
> > of restricting the sync to only IDE and SCSI? Deadlock avoidance?
>=20
> I suspect it is a deadlock prevention thing, too. I cannot say if
> it ever worked satisfactory... :)

Well, Alt-SysRq-S does work; but it obviously misses to sync a number
of filesystems.

> > I'm gonna post my patches tomorrow ...
>=20
> Thanks, that's interesting. Like I said, they are not likely to
> get to the distro soon, but I'd love to look at them.

Well, I would be astonished if you adopted before we do ;-)

Regards,
--=20
Kurt Garloff  <[e-mail]>                          Eindhoven, NL
GPG key: See mail header, key servers         Linux kernel development
SuSE Linux AG, Nuernberg, DE                            SCSI, Security

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