I think the 2.6.32.36 ext4 needs to backport this patch much likely.
Otherwise it will hit the problem I met.
http://patchwork.ozlabs.org/patch/79880/
>
> Message: 3
> Date: Wed, 13 Jul 2011 20:33:41 +0800
> From: MaoXiaoyun <tinnycloud@xxxxxxxxxxx>
> Subject: [Xen-devel] Window VM hit blue screen when dom0 uses ext4
> with extent enabled
> To: xen devel <xen-devel@xxxxxxxxxxxxxxxxxxx>
> Message-ID: <BLU157-w24C4DDC1B2F561B849C853DA470@xxxxxxx>
> Content-Type: text/plain; charset="gb2312"
>
>
> Hi:
>
> We met quite strange blue screen problem when recently shift our dom0 fs from ext3 to
> ext4. We have some IO stress test, that is in a Win2003 HVM, a process perform file reading
> and writing after the VM startup. In our dom0 host, we start totally 10 HVMS to run the test.
>
> Here is the test result
> 1) if it is ext3 in dom0, test is ok
> 2) if it is ext4 in dom0, entent feature is disabled, test is ok.
> 3) if it is ext4 in dom0, and extent feature is enable, HVMs will got blue screen one after another
> in 15 -30 minutes. And the blue screen code implys something wrong with the disk.
> (Such as KERNEL_STACK_INPAGE_ERROR,
> STOP 0x00000077(0x00000185,0x00000185,0x00000000,0x001FD000))
>
> Also serial port has some log report:
> (XEN) grant_table.c:578:d0 Iomem mapping not permitted ffffffffffffffff (domain 40)
> (XEN) grant_table.c:578:d0 Iomem mapping not permitted ffffffffffffffff (domain 40)
>
> When blue screen, I don't see any abnormal log in messages. It's surprise me since
> wi/wo extent make such big difference. We've been run VMs in ext3 quite a long time
> with no failure, I also learnt that extent is a important feature in ext4, couldn't be wrong
> so easily.
>
> So what's problem could it be ?
> Any comments?
> Thanks.
>
> BTW: we have kernel 2.6.32.36 + xen 4.0.1
>
>
