Re: [Xen-devel] [PATCH] qemu-xen-3.4-testing: Fix read-only imag

On 06/07/2010 03:19 PM, Pasi Kärkkäinen wrote:

On Mon, Jun 07, 2010 at 03:14:40PM +0200, Michal Novotny wrote:

On 06/07/2010 03:10 PM, Michal Novotny wrote:

On 06/07/2010 01:45 PM, Pasi Kärkkäinen wrote:

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

Well, no, and doesn't seem to be installed/probed:

# modprobe xen-evtchn
# lsmod | grep xen-evtchn
#

So there's the problem :(

Michal

Oh, I'm taking this back since I found out the module is not xen-evtchn
but xen_evtchn. So yeah, I'm having it loaded in the memory now.
However, when I do `service xend restart` the same error is here:

[2010-06-07 17:14:09 5635] INFO (SrvDaemon:227) Xend stopped due to
signal 15.
[2010-06-07 17:14:09 6295] INFO (SrvDaemon:332) Xend Daemon started
[2010-06-07 17:14:09 6295] INFO (SrvDaemon:336) Xend changeset: Thu May
20 17:22:15 2010 +0100 21442:a7fcf2e35d32.
[2010-06-07 17:14:09 6295] DEBUG (tcp:96) Listening on :8002
[2010-06-07 17:14:09 6295] INFO (XendNetwork:114) Not recreating missing
unmanaged network eth0
[2010-06-07 17:14:09 6295] INFO (XendNetwork:114) Not recreating missing
unmanaged network eth2
[2010-06-07 17:14:09 6295] INFO (XendNetwork:114) Not recreating missing
unmanaged network br0
[2010-06-07 17:14:09 6295] INFO (XendNetwork:114) Not recreating missing
unmanaged network xenbr0
[2010-06-07 17:14:10 6295] DEBUG (XendCPUPool:747) recreate_active_pools
[2010-06-07 17:14:10 6295] ERROR (SrvDaemon:349) Exception starting xend
((111, 'Connection refused'))
Traceback (most recent call last):
   File
"/usr/lib64/python2.4/site-packages/xen/xend/server/SrvDaemon.py", line
341, in run
     servers = SrvServer.create()
   File
"/usr/lib64/python2.4/site-packages/xen/xend/server/SrvServer.py", line
258, in create
     root.putChild('xend', SrvRoot())
   File "/usr/lib64/python2.4/site-packages/xen/xend/server/SrvRoot.py",
line 40, in __init__
     self.get(name)
   File "/usr/lib64/python2.4/site-packages/xen/web/SrvDir.py", line 84,
in get
     val = val.getobj()
   File "/usr/lib64/python2.4/site-packages/xen/web/SrvDir.py", line 52,
in getobj
     self.obj = klassobj()
   File "/usr/lib64/python2.4/site-packages/xen/xend/server/SrvNode.py",
line 30, in __init__
     self.xn = XendNode.instance()
   File "/usr/lib64/python2.4/site-packages/xen/xend/XendNode.py", line
1176, in instance
     inst = XendNode()
   File "/usr/lib64/python2.4/site-packages/xen/xend/XendNode.py", line
163, in __init__
     self._init_cpu_pools()
   File "/usr/lib64/python2.4/site-packages/xen/xend/XendNode.py", line
377, in _init_cpu_pools
     XendCPUPool.recreate_active_pools()
   File "/usr/lib64/python2.4/site-packages/xen/xend/XendCPUPool.py",
line 754, in recreate_active_pools
     uuid = xstransact.Read(path, 'uuid')
   File
"/usr/lib64/python2.4/site-packages/xen/xend/xenstore/xstransact.py",
line 307, in Read
     return complete(path, lambda t: t.read(*args))
   File
"/usr/lib64/python2.4/site-packages/xen/xend/xenstore/xstransact.py",
line 361, in complete
     t = xstransact(path)
   File
"/usr/lib64/python2.4/site-packages/xen/xend/xenstore/xstransact.py",
line 29, in __init__
     self.transaction = xshandle().transaction_start()
   File "/usr/lib64/python2.4/site-packages/xen/xend/xenstore/xsutil.py",
line 18, in xshandle
     xs_handle = xen.lowlevel.xs.xs()
Error: (111, 'Connection refused')

Any ideas?

Is xenstore running?

Are there files in /proc/xen ?

Yes to both questions. Everything seems to be OK. Also, there's optionto turn on the debugging of xenstore, right? Do you think it could help?I'm going to try it now.


Michal

-- Pasi

Michal

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>


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--
Michal Novotny<minovotn@xxxxxxxxxx>, RHCE
Virtualization Team (xen userspace), Red Hat


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--
Michal Novotny<minovotn@xxxxxxxxxx>, RHCE
Virtualization Team (xen userspace), Red Hat

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--
Michal Novotny<minovotn@xxxxxxxxxx>, RHCE
Virtualization Team (xen userspace), Red Hat

_______________________________________________
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Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel



--
Michal Novotny<minovotn@xxxxxxxxxx>, RHCE
Virtualization Team (xen userspace), Red Hat


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