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

[ramakanth varala]

Hi  Pascal..

I tried like below..

address@hidden ~]# qemu-nbd -d /dev/nbd0
/dev/nbd0 disconnected

address@hidden ~]# qemu-nbd --connect /dev/nbd0p1
/home/test/test.3.5.1b.debug/test.3.5.1b.debug.raw
qemu-nbd: Could not access '/dev/nbd0p1': No such file or directory


On Tue, Dec 4, 2018 at 4:55 PM ramakanth varala <address@hidden>
wrote:

> first time i got below..
>
> address@hidden ~]# kpartx -a /dev/ndb0
> failed to stat() /dev/ndb0
>
> from second time onwards like below..
>
> address@hidden ~]# kpartx -a /dev/nbd0
> device-mapper: resume ioctl failed: Invalid argument
>
>
> On Tue, Dec 4, 2018 at 4:23 PM Jan Schermer <address@hidden> wrote:
>
>> Partigion is missing :-)
>> try:
>> kpartx -a /dev/ndb0
>>
>>
>> > On 4 Dec 2018, at 11:35, ramakanth varala <address@hidden>
>> wrote:
>> >
>> > Hi Pascal..
>> >
>> > yes its RW ...
>> >
>> > 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            2610        2610        8032+  83  Linux
>> >
>> > address@hidden ~]# ls -ltr /dev/nbd0*
>> > brw-r----- 1 root disk 43, 0 Dec  4 11:06 /dev/nbd0
>> >
>> > address@hidden ~]# mount /dev/nbd0p1
>> /home/test/test.3.5.1b.debug/mnt/boot/
>> > mount: special device /dev/nbd0p1 does not exist
>> >
>> > 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
>> > 253     2     104391 dm-2
>> > 253     3   20860402 dm-3
>> >
>> >
>> > --Not sure..what's missing..
>> >
>> > Thanks
>> > Rama Kanth
>> >
>> > On Tue, Dec 4, 2018 at 3:07 PM Pascal <address@hidden> wrote:
>> >
>> >> hi,
>> >>
>> >> you left fdisk without saving the changes (w before q), so there can't
>> be
>> >> two partitions.
>> >> on the other hand, we should find the existing partition...
>> >> there is a strange warning when fdisk starts: what is on the over side
>> of
>> >> nbd0 ?
>> >> is /dev/nbd0 rw ?
>> >> if you can't re-read the partitions table, can you disconnect
>> /dev/nbd0 and
>> >> then reconnect it ?
>> >>
>> >>
>> >> Le lun. 3 déc. 2018 à 16:17, ramakanth varala <
>> address@hidden>
>> >> a écrit :
>> >>
>> >>> Hi ,
>> >>>
>> >>> I tried below steps .. still with some errors..
>> >>>
>> >>>
>> >>> address@hidden ~]# fdisk /dev/nbd0
>> >>>
>> >>> The number of cylinders for this disk is set to 2610.
>> >>> There is nothing wrong with that, but this is larger than 1024,
>> >>> and could in certain setups cause problems with:
>> >>> 1) software that runs at boot time (e.g., old versions of LILO)
>> >>> 2) booting and partitioning software from other OSs
>> >>>   (e.g., DOS FDISK, OS/2 FDISK)
>> >>>
>> >>> Command (m for help): n
>> >>> Command action
>> >>>   e   extended
>> >>>   p   primary partition (1-4)
>> >>> p
>> >>> Partition number (1-4): 1
>> >>> Partition 1 is already defined.  Delete it before re-adding it.
>> >>>
>> >>> Command (m for help): d
>> >>> Partition number (1-4): 1
>> >>>
>> >>> Command (m for help): d
>> >>> Selected partition 2
>> >>>
>> >>> Command (m for help): p
>> >>>
>> >>> 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
>> >>>
>> >>> Command (m for help): n
>> >>> Command action
>> >>>   e   extended
>> >>>   p   primary partition (1-4)
>> >>> p
>> >>> Partition number (1-4): 1
>> >>> First cylinder (1-2610, default 1):
>> >>> Using default value 1
>> >>> Last cylinder or +size or +sizeM or +sizeK (1-2610, default 2610): 4
>> >>>
>> >>> Command (m for help): n
>> >>> Command action
>> >>>   e   extended
>> >>>   p   primary partition (1-4)
>> >>> p
>> >>> Partition number (1-4): 2
>> >>> First cylinder (5-2610, default 5):
>> >>> Using default value 5
>> >>> Last cylinder or +size or +sizeM or +sizeK (5-2610, default 2610):
>> >>> Using default value 2610
>> >>>
>> >>> Command (m for help): p
>> >>>
>> >>> 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           4       32098+  83  Linux
>> >>> /dev/nbd0p2               5        2610    20932695   83  Linux
>> >>>
>> >>> Command (m for help): q
>> >>>
>> >>> address@hidden ~]# blockdev --rereadpt /dev/nbd0
>> >>> BLKRRPART: Invalid argument
>> >>> address@hidden ~]# ls /dev/nbd0
>> >>> /dev/nbd0
>> >>> address@hidden ~]# ls /dev/nbd0*
>> >>> /dev/nbd0
>> >>>
>> >>>
>> >>>
>> >>> Thanks
>> >>> Rama Kanth
>> >>>
>> >>> On Fri, Nov 30, 2018 at 6:48 PM Pascal <address@hidden> wrote:
>> >>>
>> >>>> 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
>> >>>>>>>
>> >>>>>>>
>> >>>>>>>
>> >>>>>>
>> >>>>>
>> >>>>
>> >>>
>> >>
>>
>>