Re: Minidisk support
On 2009-12-15, Stephen Powell wrote:
> My own attempts to backport the official fix to 2.6.26 have so far been
> unsuccessful due to my minuscule C skills. I'm getting compile errors
> that I have so far not been able to resolve. Fortunately, I have a
> simpler patch that works well enough for me.
Well, I finally succeeded in backporting the official DIAG patch from
2.6.33 to 2.6.26. I was having trouble earlier with substitution parameters
in messages (like %s, %d, etc.). I finally figured out how that stuff
works well enough to backport the fix to 2.6.26 (i.e. Lenny). Of course,
it's unofficial. It doesn't come directly from the kernel people. But
I have tested it, and it applies cleanly, compiles cleanly, and appears
to execute correctly. I tested it as well as I could on my system, and
it works great. Here is a link to the backported patch, if anyone wants it:
http://www.wowway.com/~zlinuxman/dasd_diag.patch
For reference again, here is the upstream commit link, courtesy of
Peter Oberparleiter:
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=22825ab7693fd29769518a0d25ba43c01a50092a
P.S. I wonder if we could make a case for including this fix in Lenny
on "security" grounds? The rationale would be that without this patch,
sharing minidisks with the DIAG driver requires multiple simultaneous
read/write links (access mode MW), which carries with it the risk that
two different servers might accidentally mount the file system read/write
at the same time, which will corrupt the minidisk. With the patch, the
minidisks can be linked read-only, which eliminates the risk.
Of course, I am not an upstream kernel person, nor a Debian developer,
nor a Debian security person; so someone would have to step up and
sponsor this. Just a thought. Suse apparently thought the fix important
enough to backport it to SLES10 (2.6.16) and SLES11 (2.6.27). So if
Debian decided to do this they would be in good company.
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