On Wed, Nov 20, 2019 at 10:37:14AM +0000, Daniel P. Berrangé wrote:
On Wed, Nov 20, 2019 at 11:34:24AM +0100, Michal Privoznik wrote:
On 11/20/19 11:05 AM, Daniel P. Berrangé wrote:
On Wed, Nov 20, 2019 at 10:51:47AM +0100, Michal Privoznik wrote:
Another weird bug appeared concerning qemu namespaces. Basically the problem is as follows:
1) Issue an API that causes libvirt to create a node in domain's namespace, say /dev/sda with 8:0 as major:minor (the API can be attach-disk for instance). Or simply create the node from a console by hand.
2) Detach the disk from qemu.
3) Do something that makes /dev/sda change it's minor number.
Wait, what ?
major/minor numbers for SCSI disks are a defined standard IIUC
$ grep SCSI ./admin-guide/devices.txt | grep block 8 block SCSI disk devices (0-15) 11 block SCSI CD-ROM devices 65 block SCSI disk devices (16-31) 66 block SCSI disk devices (32-47) 67 block SCSI disk devices (48-63) 68 block SCSI disk devices (64-79) 69 block SCSI disk devices (80-95) 70 block SCSI disk devices (96-111) 71 block SCSI disk devices (112-127) 128 block SCSI disk devices (128-143) 129 block SCSI disk devices (144-159) 130 block SCSI disk devices (160-175) 131 block SCSI disk devices (176-191) 132 block SCSI disk devices (192-207) 133 block SCSI disk devices (208-223) 134 block SCSI disk devices (224-239) 135 block SCSI disk devices (240-255)
IOW, /dev/sda should always be 8,0
There is, however, the possibiity of dynamically assign major/minor numbers so its possible we'll see a block device with a changable number, but AFAIK, such a block device should never be call /dev/sda !??!
IOW, the commit is fine, but is this commit message really accurate ?
Ah, the bug talks about /dev/nvmeN that has changed MIN number. I haven't found corresponding docs on NVMe though. Is s/sda/nvmeN/ on the commit message enough?
Yeah, that makes more sense as nvme devices are allocated from the dynamic range.
Opps, I should have added Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|