On 2013年03月13日 15:38, Osier Yang wrote: > On 2013年03月13日 15:20, yuxh wrote: >> On 03/13/2013 11:33 AM, Osier Yang wrote: >>> On 2013年03月13日 11:04, yuxh wrote: >>>> To Osier Yang >>>> >>>> Sorry for disturbing you on the working time, but I really need your >>>> help. >>>> I met a problem when I do the virtualization test on the >>>> environment of >>>> (Host: RHEL6.4GA. Guest: RHEL6.4GA) and it seems to have relationship >>>> with your patch of "util: Prepare helpers for unpriv_sgio setting". >>> >>> Never mind, it's the bug I produced. :( >>> >>>> >>>> I added a disk to virtio-scsi bus through the VM's XML file like >>>> this: >>>> <disk type='block' device='disk'> >>>> <driver name='qemu' type='raw' io='threads'/> >>>> <source dev='/mnt/test.raw'/> >>>> <target dev='sdb' bus='scsi'/> >>>> <shareable/> >>>> </disk> >>>> >>>> Then when I started the VM, I met the error. >>>> [root@build SOURCES]# virsh start pan64ga >>>> error: Failed to start domain pan64ga >>>> error: Unable to get minor number of device '/mnt/test.raw': Invalid >>>> argument >>>> >>>> [root@build SOURCES]# >>>> >>>> I tried other source files and other way of using if and I found: >>>> 1). If we use the files which format is raw, qed and qcow2 as the >>>> disk >>>> this error occur again. >>>> 2). If we use partition(such as /dev/sdb1) or whole disk(such as >>>> /dev/sdb) this error doesn't occur. >>>> 3). If we delete the "<shareable/>" then files, partition and disk >>>> all >>>> can be used correctly. >>>> >>>> And I investigate the error msg. it is returned by >>>> qemuGetSharedDiskKey >>>> fuction. >>>> char * >>>> qemuGetSharedDiskKey(const char *disk_path) >>>> { >>>> ... >>>> // error occur here. return value is -22 >>>> if ((rc = virGetDeviceID(disk_path, &maj, &min)) < 0) { >>>> virReportSystemError(-rc, >>>> _("Unable to get minor number of device '%s'"), >>>> disk_path); >>>> return NULL; >>>> } >>>> ... >>>> } >>>> >>>> Go on the virGetDeviceID fuction: >>>> int >>>> virGetDeviceID(const char *path, int *maj, int *min) >>>> { >>>> ... >>>> >>>> if (!S_ISBLK(sb.st_mode)) { >>>> VIR_FREE(canonical_path); >>>> return -EINVAL; // error occur here and it return -22 >>>> } >>>> ... >>>> } >>>> >>>> So the error occur place is "S_ISBLK(sb.st_mode)" and I tried >>>> compiled >>>> the libvirt with these lines deleted and the error didn't happen >>>> again. >>>> Also I checked the disk if VM and it worked well. >>>> I found this fuction virGetDeviceID is come from your patch of "util: >>>> Prepare helpers for unpriv_sgio setting". But I am not familiar with >>>> libvirt. >>>> So I have to consult with you about whether this "S_ISBLK" check is >>>> vital and If we can delete it or >>>> find out some method to avoid this error so we can use the file as >>>> shared disk in VM. >>> >> Sorry, I have tried the the libvirt's upstream code and it still have >> this error. >> According to the code, if we use "<disk type='block' device='disk'> " >> and "<shareable/> " to set the disk's configuration in VM's XML >> file, it >> will go through like below: >> >> int >> qemuAddSharedDisk(virQEMUDriverPtr driver, >> virDomainDiskDefPtr disk, >> const char *name) >> { ... >> if (!(key = qemuGetSharedDiskKey(disk->src))) >> goto cleanup; >> ... >> } >> >> char * >> qemuGetSharedDiskKey(const char *disk_path) >> { >> ... >> if ((rc = virGetDeviceID(disk_path, &maj, &min)) < 0) { >> virReportSystemError(-rc, >> _("Unable to get minor number of device '%s'"), >> disk_path); >> return NULL; >> } >> ... >> } >> >> int >> virGetDeviceID(const char *path, int *maj, int *min) >> { >> struct stat sb; >> >> if (stat(path, &sb) < 0) >> return -errno; >> >> if (!S_ISBLK(sb.st_mode)) >> return -EINVAL; >> >> if (maj) >> *maj = major(sb.st_rdev); >> if (min) >> *min = minor(sb.st_rdev); >> >> return 0; >> } >> >> To make a long story short, the virGetDeviceID fuction want to get the >> maj and min number of the source file which we provided as the VM's >> disk. But the file such as /mnt/test.raw doesn't have the maj and min >> number. >> So virGetDeviceID return " -EINVAL" and qemuGetSharedDiskKey print the >> error message of "Unable to get minor number of device /mnt/test.raw". >> That's the reason the VM can't be started. >> So I just want to know now, if the way I used a file to act as VM's >> disk >> and set "<disk type='block' device='disk'>" , "<shareable/> " at the >> same time is reasonable. > > Hum, sorry I didn't read your problem carefully. But... > > It's not reasonable. As the disk source you use is /mnt/test.raw, I > believe it's not a block device. However, you used disk type='block'. > Libvirt honors what you specified, and tries to grab the device IDs > of the disk source (it expects the disk source is block, but it's not). > > Regards, > Osier

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