Re: [Xen-devel] [PATCH] qemu-xen-3.4-testing: Fix read-only image file handling

[Pasi Kärkkäinen <pasik@xxxxxx>]

On Mon, Jun 07, 2010 at 01:21:21PM +0200, Michal Novotny wrote:
> Well, I'm still having some tools issues, mainly:
>
> Error: (111, 'Connection refused')
>
> Any guess what may be going wrong? Booted grub entry:
>
> title Red Hat Enterprise Linux Server (2.6.31.13-xen HV, nolog)
>         root (hd1,6)
>         kernel /xen-4.1-unstable.gz
>         module /vmlinuz-2.6.31.13 ro root=LABEL=/rhel2 rhgb quiet selinux=0
>         module /initrd-2.6.31.13.img
>
> Mount is having `xenfs on /proc/xen type xenfs (rw)`. Any guess what may  
> be going wrong?
>


Do you have xen-evtchn driver loaded? 


-- Pasi


> Thanks,
> Michal
>
> On 06/04/2010 12:42 PM, Pasi Kärkkäinen wrote:
>> On Fri, Jun 04, 2010 at 11:37:51AM +0200, Michal Novotny wrote:
>>    
>>> Oh, one more thing I've discovered now. Since the codebase for
>>> qemu-xen-unstable is looking the same like for qemu-xen-3.4-testing and
>>> the patch is applicable without any modifications it could be working
>>> for xen-4.1 unstable as well, unfortunately I was not able to boot PVOPS
>>> kernel since it always ends up in kernel panic, maybe the missing
>>> drivers or something like that.
>>>
>>>      
>> What kernel version? Did you use xen/stable-2.6.32.x branch from xen.git?
>>
>> See my example .config files from:
>> http://wiki.xensource.com/xenwiki/XenParavirtOps in the "troubleshooting" 
>> section.
>>
>> Works on F12/F13 dom0's.
>>
>> For el5 dom0 you might need these:
>> http://wiki.xensource.com/xenwiki/2.6.18-to-2.6.31-and-higher
>>
>> aka
>> CONFIG_SYSFS_DEPRECATED=y
>> CONFIG_SYSFS_DEPRECATED_V2=y
>>
>> Also atm I think you need CONFIG_XEN_XENBUS_FRONTEND=y in the .config
>> because of the recently added pv-on-hvm drivers (you'll get build failure 
>> without that option),
>> so you need XEN_PCIDEV_FRONTEND XEN_BLKDEV_FRONTEND or XEN_NETDEV_FRONTEND 
>> or XEN_FBDEV_FRONTEND needs to be =y.
>>
>> -- Pasi
>>
>>
>>    
>>> On 06/03/2010 04:12 PM, Michal Novotny wrote:
>>>      
>>>> Oh, just one more thing that should be mentioned:
>>>>
>>>> When you want to mount an image that is set as read-only in the domain
>>>> configuration file but you omit to set mode to read-only it results
>>>> into I/O errors when processing the requests. Remounting as read-only
>>>> or unmounting and remounting using the `mount /dev/* /path/to/mount -o
>>>> ro` shall do the mounting the correct way, i.e. with no I/O errors, so
>>>> make sure you mount those disks as read-only otherwise you can be
>>>> getting errors like:
>>>>
>>>> end_request: I/O error, dev hdb, sector 52
>>>>
>>>> Buffer I/O error on device hdb1, logical block 1
>>>>
>>>> lost page write due to I/O error on hdb1
>>>>
>>>>
>>>> and for IDE devices you'll be getting several additional DeviceFault
>>>> errors since mounting the device read-write (default setting) writes
>>>> some data onto a disk at the mount-time.
>>>>
>>>> Michal
>>>>
>>>> On 06/03/2010 04:04 PM, Michal Novotny wrote:
>>>>        
>>>>> [Well, I did send an e-mail to the list using git but it's not here
>>>>> so I'm forwarding the e-mail to the list for sure:]
>>>>>
>>>>> Hi,
>>>>> this is the patch for qemu-xen-3.4-testing to fix the read-only
>>>>> image file handling since the image file was always treated as
>>>>> read-write which means that all the HVM guests were able to
>>>>> write to all the disk images available in domain configuration
>>>>> file no matter what the mode of the image was defined. This
>>>>> patch fixes this functionality to honor the O_RDONLY in the
>>>>> BDRV_O_ACCESS flag in block.c and also fixes the IDE and SCSI
>>>>> interfaces that uses it.
>>>>>
>>>>> It's been tested on RHEL-5 with xen-3.4-testing version of
>>>>> upstream xen with xen-3.4-testing qemu implementation.
>>>>>
>>>>> For SCSI devices the DATA PROTECT request sense has been added
>>>>> as found at: http://en.wikipedia.org/wiki/SCSI_Request_Sense_Command
>>>>>
>>>>> file no matter what the mode of the image was defined. This
>>>>> patch fixes this functionality to honor the O_RDONLY in the
>>>>> BDRV_O_ACCESS flag in block.c and also fixes the IDE and SCSI
>>>>> interfaces that uses it.
>>>>>
>>>>> It's been tested on RHEL-5 with xen-3.4-testing version of
>>>>> Michal
>>>>>
>>>>> Signed-off-by: Michal Novotny<minovotn@xxxxxxxxxx>
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> Xen-devel mailing list
>>>>> Xen-devel@xxxxxxxxxxxxxxxxxxx
>>>>> http://lists.xensource.com/xen-devel
>>>>>          
>>>>
>>>>        
>>>
>>> -- 
>>> Michal Novotny<minovotn@xxxxxxxxxx>, RHCE
>>> Virtualization Team (xen userspace), Red Hat
>>>
>>>
>>> _______________________________________________
>>> Xen-devel mailing list
>>> Xen-devel@xxxxxxxxxxxxxxxxxxx
>>> http://lists.xensource.com/xen-devel
>>>      
>
>
> -- 
> Michal Novotny<minovotn@xxxxxxxxxx>, RHCE
> Virtualization Team (xen userspace), Red Hat
>

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