Re: [Qemu-discuss] Issue related to mounting /dev/nbd0p1

[Pascal]

do not create nodes manually but with fdisk on nbd0 :

# fdisk /dev/nbd0
## now create your partitions in fdisk
## use w to write changes and q to quit fdisk

# blocdev --rereadpt /dev/nbd0

# ls /dev/nbd0*
## you will now have /dev/nbd0, /dev/nbd0p1 and /dev/nbd0p2

if this is not the case while the fdisk command ended without error :

# sync
# qemu-nbd -d /dev/nbd0
# qemu-nbd -c /dev/nbd0 /the/target


Le ven. 30 nov. 2018 à 14:04, ramakanth varala <address@hidden>
a écrit :

> Hi Pascal & Jakob,
>
> I started from first .
>
> I created manully the partitions as below
>
>    27  mknod /dev/nbd0p1 b 1 4
>    28  mknod /dev/nbd0p2 b 1 4
>
> still in /proc/partitions i don't see any info , it shows as below
>
> address@hidden ~]# cat /proc/partitions
> major minor  #blocks  name
>
>    8     0   62914560 sda
>    8     1     104391 sda1
>    8     2   62806117 sda2
>  253     0   56655872 dm-0
>  253     1    6127616 dm-1
>
> address@hidden ~]# fdisk  -l /dev/nbd0
>
> Disk /dev/nbd0: 21.4 GB, 21474836480 bytes
> 255 heads, 63 sectors/track, 2610 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
>
>      Device Boot      Start         End      Blocks   Id  System
> /dev/nbd0p1   *           1          13      104391   83  Linux
> /dev/nbd0p2              14        2610    20860402+  8e  Linux LVM
>
>
> when i try for mount , i see below error
>
>
> address@hidden ~]# mount /dev/nbd0p1
> /home/test/test.3.5.1b.debug/mnt/boot
> mount: you must specify the filesystem type
>
> i tried to give file system type as below, still issues.
>
> address@hidden ~]# mount -t ext3 /dev/nbd0p1
> /home/test/test.3.5.1b.debug/mnt/boot
> mount: wrong fs type, bad option, bad superblock on /dev/nbd0p1,
>        missing codepage or other error
>        In some cases useful info is found in syslog - try
>        dmesg | tail  or so
>
>
> Any inputs would be really helpfull..
>
>
> Thanks
> Rama Kanth
>
> On Fri, Nov 30, 2018 at 1:50 PM Pascal <address@hidden> wrote:
>
>> restart from zero if possible...
>>
>> # qemu-nbd -d /dev/nbd0
>> # modprobe -rv nbd
>>
>> # modprobe nbd
>> # qemu-nbd -c /dev/nbd0 /the/file
>> # blockdev --rereadpt /dev/nbd0
>> # fdisk -l /dev/nbd0
>> # mount /dev/nbd0p1 /mount/point
>>
>> Le jeu. 29 nov. 2018 à 17:32, Jakob Bohm <address@hidden> a
>> écrit :
>>
>> > Check
>> >
>> >     cat /proc/partitions
>> >
>> > If the partitions are not listed there, the kernel does not
>> > recognize them, perhaps the kernel doesn't recognize that
>> > nbd0 is a "partitionable disk", and thus does not create the
>> > internal nbd0p1 and ndb0p2 devices.
>> >
>> > If the partitions are listed there, you just need to create the
>> > actual /dev/nbd0p1 and /dev/nbd0p2 file names with mknod or
>> > figure out why your "/dev/" management software (maybe udev,
>> > maybe something better) doesn't do that for you.
>> >
>> > On 29/11/2018 12:46, ramakanth varala wrote:
>> > > Still with some errors..
>> > >
>> > > address@hidden ~]# kpartx -a /dev/nbd0
>> > > read error, sector 0
>> > > read error, sector 1
>> > > read error, sector 29
>> > > address@hidden ~]# ls /dev/nbd
>> > > nbd0   nbd1   nbd10  nbd11  nbd12  nbd13  nbd14  nbd15  nbd2   nbd3
>> >  nbd4
>> > >   nbd5   nbd6   nbd7   nbd8   nbd9
>> > >
>> > >
>> > >
>> > > On Thu, Nov 29, 2018 at 4:22 PM Nerijus Baliūnas <
>> > > address@hidden> wrote:
>> > >
>> > >> Please try kpartx -a /dev/nbd0
>> > >>
>> > >> 2018-11-29 12:38, ramakanth varala rašė:
>> > >>> thanks for the reply ..
>> > >>>
>> > >>> But i get below error when i do ..
>> > >>>
>> > >>>
>> > >>> address@hidden ~]# partx -a /dev/nbd0
>> > >>> HDIO_GETGEO: Inappropriate ioctl for device
>> > >>>
>> > >>> On Thu, Nov 29, 2018 at 4:04 PM Nerijus Baliūnas <
>> > >>> address@hidden> wrote:
>> > >>>
>> > >>>> 2018-11-29 12:10, ramakanth varala rašė:
>> > >>>>> address@hidden ~]# mount /dev/nbd0p1
>> /home/test.1.3.debug/mnt/boot
>> > >>>>> mount: special device /dev/nbd0p1 does not exist
>> > >>>> partx -a /dev/nbd0
>> > >>>>
>> >
>> >
>> > Enjoy
>> >
>> > Jakob
>> > --
>> > Jakob Bohm, CIO, Partner, WiseMo A/S.  https://www.wisemo.com
>> > Transformervej 29, 2860 Søborg, Denmark.  Direct +45 31 13 16 10
>> > This public discussion message is non-binding and may contain errors.
>> > WiseMo - Remote Service Management for PCs, Phones and Embedded
>> >
>> >
>> >
>>
>