CentOS - Feb 2007 - Latest Plus Kernel include MD RAID-1 BIO_RW_SYNC patch?

I am inquiring on the list if anybody knows if the latest plus kernel
includes the fixes for MD RAID-1 where it didn't pass down the
BIO_RW_SYNC flag on cloned bios.

This bug was discovered in December by the DRBD project and patches were
posted by Lars Ellenberg from that project to the LKM which were then
merged into the 2.6.19 kernel.

The bug causes severe performance penalties for applications that use
the BIO_RW_SYNC flag on block requests.

The fix is a simple 2 to 4 line change where it ORs the sync flag on the
cloned bios.

If it isn't in the plus kernel, how would one go about putting a request
to have it included?


Thanks,


Ross S. W. Walker
Information Systems Manager
Medallion Financial, Corp.
437 Madison Avenue
38th Floor
New York, NY 10022
Tel: (212) 328-2165
Fax: (212) 328-2125
WWW: http://www.medallion.com <http://www.medallion.com> 



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On Fri, 2007-02-23 at 14:01 -0500, Ross S. W. Walker
wrote:
> I am inquiring on the list if anybody knows if the latest plus kernel
> includes the fixes for MD RAID-1 where it didn't pass down the
> BIO_RW_SYNC flag on cloned bios.
> 
> This bug was discovered in December by the DRBD project and patches were
> posted by Lars Ellenberg from that project to the LKM which were then
> merged into the 2.6.19 kernel.
> 
> The bug causes severe performance penalties for applications that use
> the BIO_RW_SYNC flag on block requests.
> 
> The fix is a simple 2 to 4 line change where it ORs the sync flag on the
> cloned bios.
> 
> If it isn't in the plus kernel, how would one go about putting a
request
> to have it included?
> 
Ross,

We don't normally include external patches in the CentOSPlus kernel ...
just change options in the config file, however since we also do support
DRBD and heartbeat in CentOS Extras I would be willing to try to make
this happen in the Plus Kernel.

Have you been able to roll this patch in to the current Plus kernel?

Thanks,
Johnny Hughes


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> -----Original Message-----
> From: centos-bounces at centos.org 
> [mailto:centos-bounces at centos.org] On Behalf Of Johnny Hughes
> Sent: Friday, February 23, 2007 4:46 PM
> To: CentOS ML
> Subject: Re: [CentOS] Latest Plus Kernel include MD RAID-1 
> BIO_RW_SYNC patch?
> 
> On Fri, 2007-02-23 at 14:01 -0500, Ross S. W. Walker wrote:
> > I am inquiring on the list if anybody knows if the latest 
> plus kernel
> > includes the fixes for MD RAID-1 where it didn't pass down the
> > BIO_RW_SYNC flag on cloned bios.
> > 
> > This bug was discovered in December by the DRBD project and 
> patches were
> > posted by Lars Ellenberg from that project to the LKM which 
> were then
> > merged into the 2.6.19 kernel.
> > 
> > The bug causes severe performance penalties for 
> applications that use
> > the BIO_RW_SYNC flag on block requests.
> > 
> > The fix is a simple 2 to 4 line change where it ORs the 
> sync flag on the
> > cloned bios.
> > 
> > If it isn't in the plus kernel, how would one go about 
> putting a request
> > to have it included?
> > 
> 
> Ross,
> 
> We don't normally include external patches in the CentOSPlus 
> kernel ...
> just change options in the config file, however since we also 
> do support
> DRBD and heartbeat in CentOS Extras I would be willing to try to make
> this happen in the Plus Kernel.
> 
> Have you been able to roll this patch in to the current Plus kernel?
I haven't tried yet to tell you the truth. I can give it a shot and if I
get the patch as-is to work I can post it to... Which list should I use
for that, is there a CentOS developers list?

-Ross

______________________________________________________________________
This e-mail, and any attachments thereto, is intended only for use by
the addressee(s) named herein and may contain legally privileged
and/or confidential information. If you are not the intended recipient
of this e-mail, you are hereby notified that any dissemination,
distribution or copying of this e-mail, and any attachments thereto,
is strictly prohibited. If you have received this e-mail in error,
please immediately notify the sender and permanently delete the
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