Re: exception looking up device number f,or hda

[Arun Sharma <arun.sharma@intel.com>]

Anthony Liguori wrote:
> Hi Arun,
> 
> I just pulled the latest unstable and could not reproduce.  I have an 
> identical scenario (no /dev/hda only /dev/sda due to SATA).
> 
> Also, if the devno resolution code fails you should also get a vbd: 
> Device not found exception in the logs.  The exception you are seeing is
> not actually a problem, it just means that stat has failed.
> 
> We should probably cleanup that error message.
> 
> Can you post a more complete log file?  I think the error is being 
> caused somewhere else.
> 

Hi Anthony,

You're probably not able to reproduce the problem because you're not 
using VMX domains?

We're overloading the semantics of

disk = [ 'file:/var/images/min-el3-i386.img,hda,w' ]

to create a IDE hard drive for a VMX domain. So we want to take 
advantage of the config file parsing code from the VBD code path, but we 
don't want to do other tasks such as connecting the backend/frontend etc.

The log from a successful VMX domain startup looks like:

[2005-08-05 14:54:41 xend] INFO (XendRoot:126) EVENT> xend.domain.create 
['fc3', 2]
[2005-08-05 14:54:42 xend] ERROR (process:37) [block-file] ioctl: 
LOOP_SET_FD: Device or resource busy
[2005-08-05 14:54:42 xend] DEBUG (blkif:81) Connecting blkif 
<BlkifBackend frontend=2 backend=0 id=0>
[2005-08-05 14:54:42 xend] DEBUG (blkif:89) send_be_create <BlkifBackend 
frontend=2 backend=0 id=0>
[2005-08-05 14:54:42 xend] DEBUG (image:293) args: cdrom, val: None
[2005-08-05 14:54:42 xend] DEBUG (image:293) args: boot, val: c
[2005-08-05 14:54:42 xend] DEBUG (image:293) args: fda, val: None
[2005-08-05 14:54:42 xend] DEBUG (image:293) args: fdb, val: None
[2005-08-05 14:54:42 xend] DEBUG (image:293) args: localtime, val: None
[2005-08-05 14:54:42 xend] DEBUG (image:293) args: serial, val: None
[2005-08-05 14:54:42 xend] DEBUG (image:293) args: std-vga, val: None
[2005-08-05 14:54:42 xend] DEBUG (image:293) args: isa, val: None
[2005-08-05 14:54:42 xend] INFO (image:352) spawning device models: 
/usr/lib/xen/bin/qemu-dm ['/usr/lib/xen/bin/qemu-dm', '
-vncconnect', '143.183.130.223:5502', '-d', '2', '-p', '19', '-m', 
'128', '-boot', 'c', '-hda', '/var/images/min-el3-i386.i
mg', '-vnc', '-k', 'en-us', '-vncport', '5902']

i.e. we were doing things which we really shouldn't be doing, but it 
didn't hurt. But it started hurting today :)

In the future, we're also planning to have a VBD driver for unmodified 
OSes running on VMX domains and I was thinking of a syntax such as:

disk = [ 'file:/var/images/min-el3-i386.img,vhda,w' ]

Any comments/suggestions on the syntax above to present emulated real 
devices as well as virtual devices to an unmodified OS?

	-Arun

Complete log for the failed case:

[2005-08-05 14:40:33 xend] INFO (SrvDaemon:300) Xend Daemon started
[2005-08-05 14:40:33 xend] INFO (channel:148) Virq 3 on port 13
[2005-08-05 14:40:33 xend] DEBUG (XendDomainInfo:171) 
info={'vcpu_to_cpu': [0, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 
-1, -1], 'cpu_time': 20984020436L, 'ssidref': 0, 's
hutdown_reason': 0, 'dying': 0, 'dom': 0, 'running': 1, 'maxmem_kb': -4, 
'paused': 0, 'crashed': 0, 'vcpus': 1, 'shutdown':
  0, 'mem_kb': 250880, 'cpumap': [-1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0], 'blocked': 0}
[2005-08-05 14:40:33 xend] DEBUG (XendDomainInfo:172) config='None'

[2005-08-05 14:40:33 xend] INFO (SrvServer:63) unix 
path=/var/lib/xend/xend-socket
[2005-08-05 14:40:33 xend] INFO (XendRoot:126) EVENT> xend.start 0
[2005-08-05 14:40:33 xend] INFO (process:35) [network] network start 
bridge=xen-br0 netdev=eth0 antispoof=no
[2005-08-05 14:40:53 xend] DEBUG (image:135) initDomain: cpu=-1 
mem_kb=131204 ssidref=-1 dom=1
[2005-08-05 14:40:53 xend] DEBUG (XendDomainInfo:673) init_domain> 
Created domain=1 name=ExampleVMXDomain memory=128
[2005-08-05 14:40:53 xend] INFO (XendRoot:126) EVENT> xend.domain.create 
['ExampleVMXDomain', 1]
[2005-08-05 14:40:53 xend] INFO (image:190) buildDomain os=vmx dom=1 vcpus=1
[2005-08-05 14:40:53 xend] INFO (image:259) VMX device model port: 3
[2005-08-05 14:40:53 xend] WARNING (XendDomainInfo:924) Unknown config 
field memmap
[2005-08-05 14:40:53 xend] WARNING (XendDomainInfo:924) Unknown config 
field device_model
[2005-08-05 14:40:53 xend] WARNING (XendDomainInfo:924) Unknown config 
field boot
[2005-08-05 14:40:53 xend] WARNING (XendDomainInfo:924) Unknown config 
field vnc
[2005-08-05 14:40:53 xend] WARNING (XendDomainInfo:924) Unknown config 
field display
[2005-08-05 14:40:53 xend] DEBUG (blkif:24) exception looking up device 
number for hda: [Errno 2] No such file or directory
: '/dev/hda'
[2005-08-05 14:40:53 xend] DEBUG (blkif:449) Destroying blkif domain=1
[2005-08-05 14:40:53 xend] DEBUG (blkif:337) Destroying vbd domain=1 id=0

 >>>> xend dies here <<<

[2005-08-05 14:43:32 xend] INFO (SrvDaemon:300) Xend Daemon started