[DRBD-user] drbd uml 2.6.6

Mark Olliver mpo at thermeoneurope.com
Thu May 13 11:05:01 CEST 2004

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

Hi Lars 

Thanks for this information, i think it will prove very usefully. If you 
could upload a full patch and config that would be great.



Lars Ellenberg wrote:

>/ 2004-05-12 16:19:08 +0100
>\ Mark Olliver:
>>I just want to check if anyone has managed or knows of any problems of 
>>using kernel 2.6.6 with the skas uml patch applied and drbd??
>I was using 2.6.5, and since about three hours I'm using 2.6.6 UML as my
>main test setup. If you want, I can upload my config and full patch
>somewhere on drbd.org.
>basically it is 
> kernel.org 2.6.6,
>plus some patches from http://www.user-mode-linux.org/~blaisorblade/ ,
> uml-patch-2.6.6-01.bz2,  # which applies cleanly
> patch-2.6.6-v2,          # some offsets, no fuzz
> and finally
> host+Uml-skas3-2.6.6-v1.patch
>there has been exactly *one* reject in one of the last two patches,
>iirc for include/asm-um/irq.h, which was easily applied by hand.
>then, of course, in drbd, make kernel-patch KDIR=/...2.6.6+UML.../
>and applie.
>make menuconfig ARCH=um, enable DRBD, make linux ARCH=um,
>and there you go.
>generic problems:
>  the 2.6.6 uml hostfs seems to have reintroduced a weird bug, not closing
>  file desctiptors *on the host* properly, thus the UML instance runs into
>  "too many open files". so don't use hostfs too much, until they sorted
>  that out, or someone please explain to me what I am doing wrong...
>  it seemed to have worked fine with my previous setup,
>  2.6.5 + uml-patch-2.6.4-1 + some skas and whatnot patches
>drbd related:
>  drbd seems to work fine, as well as module, and as "monolithic" build.
>  XFS seems to work on top of DRBD within uml, and survives a tiobench.
>  but sometimes, if you copy many files, it get stuck waiting for some xfs
>  internal semaphore to be released, which never happens.
>  this only shows on top of drbd, not using the underlying ubd directly,
>  but seems to be a xfs internal problem, since it even shows when DRBD
>  is "virgin standalone", just passing request to the lower level device,
>  and passing end_io events up to the upper levels. with a recently
>  introduce atomic counter I can *prove* that drbd did the correct endio.
>  only xfs seems to not up its own semaphore properly...
>  as soon as this is reproducable in real systems (where currently xfs on
>  top of DRBD seems to have all sorts of other weird problems, which I
>  doubt are DRBDs fault... only xfs does not expect the restrictions that
>  the DRBD requests queue imposes), this needs to be sorted out with the
>  XFS guys... 
>otherwise, doing uml is fun.
>hav a look into drbd/testing, where there is a script named
>uml-screen-debug, which I found very useful to start my umls.
>	Lars Ellenberg
>drbd-user mailing list
>drbd-user at lists.linbit.com

Mark Olliver

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