Re: FreeBSD HVM+PV domU hangs on boot -- but not if using file-backed storage

[Hugo Silva <hugo%barafranca.com@localhost>]

Adam Hamsik wrote:
> On May,Thursday 27 2010, at 11:25 AM, Hugo Silva wrote:
>
>   
> > It doesn't mean much but I was able to run HVM+PV FreeBSD many months ago on a 
> > Debian dom0, also with lvm-backed storage. I can't test that now either, as the 
> > machine happily runs NetBSD -current these days.
> >
> >
> > The only remotely suspect message I was able to find while booting the domUis:
> > xbdback backend/vbd/3/768: unknown device 0xc207 (major=194)
> >     
>
> 194 is major number of device-mapper (aka lvm) devices. Can you debug this issue more ? But I'm really not sure where to start. Is this message from xen tools or from kernel ? 
>   

It is from the kernel.
> It looks like that it can be from xbdback_xenbus.c#691
>
>         if (mode[0] == 'w')
>                 xbdi->xbdi_ro = 0;
>         else
>                 xbdi->xbdi_ro = 1;
>         major = major(xbdi->xbdi_dev);
>         devname = devsw_blk2name(major);
>         if (devname == NULL) {
>                 printf("xbdback %s: unknown device 0x%"PRIx64"\n",
>                     xbusd->xbusd_path, xbdi->xbdi_dev);
>                 return;
>         }
>
> But my sources are different I can't find '(major=194)' there. Can you post 
> your part of these sources or add printfs there to confirm this theory ?
>   

You are correct, it comes from xbdback_xenbus.c.

# mv xbdback_xenbus.c xbdback_xenbus.c.orig
# cvs update -P -d
cvs update: Updating .
cvs update: warning: xbdback_xenbus.c was lost
U xbdback_xenbus.c
# diff xbdback_xenbus.c xbdback_xenbus.c.orig
693,694c693,694
< printf("xbdback %s: unknown device 0x%"PRIx64"\n",
< xbusd->xbusd_path, xbdi->xbdi_dev);
---
> printf("xbdback %s: unknown device 0x%"PRIx64" (major=%d)\n",
> xbusd->xbusd_path, xbdi->xbdi_dev, major);


I must have added the major=%d myself during one of our previous debug 
sessions. Oops :-)
> How many lvm devices do you use ? Because I can't really see how this can fail 
> for some domU and work for other.
>
>
> Regards
>
> Adam.
>
>   
# lvm lvs
File descriptor 3 () leaked on lvm invocation. Parent PID 71:
Found duplicate PV Vl95SzA75G4TqDSLC2F3vOvrkd1wGiFC: using /dev/rraid1d 
not /dev/rraid1a
Found duplicate PV 2phD1fxXEmHvIbXxMeaClrVNe8BknhDM: using /dev/rraid2d 
not /dev/rraid2a
LV VG Attr LSize Origin Snap% Move Log Copy% Convert
fileserver vg1 -wi-a- 24.00g
ftest vg1 -wi-a- 4.00g
obsdtest vg1 -wi-a- 4.00g
pythondev vg1 -wi-a- 24.00g
pythondev2 vg1 -wi-a- 16.00g
wiki vg1 -wi-a- 8.00g
wiki-data0 vg1 -wi-a- 4.00g


This is on NetBSD 5.99.29 amd64, by the way.

I don't rule out the possibility that this could be some file I edited 
or some patch I forgot to reapply. Could someone confirm FreeBSD's 
XENHVM with lvm also hangs? Instructions are on my previous email -- 
shouldn't take more than 20 minutes.

Adam, if there are no volunteers I will update my -current and give it 
another go with fresh sources. This reminds me - the block-raw.diff 
patch, was it integrated in pkgsrc?

p.s: I've always wondered what the above "File descriptor 3 () leaked on 
lvm invocation" means. Is it harmless? I see some of them during dom0 boot.
p.p.s: Same for "Found duplicate PV". It seems to be harmless as lvm 
works, but as far as I remember I've always seen these messages. Now I'm 
wondering. Is it normal?