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

[Pascal]

try to disconnect and then re-connect the exported (network) device (eg.
the over side)...

Le mar. 4 déc. 2018 à 11:53, Jan Schermer <address@hidden> a écrit :

> 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
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>
> >>>>>
> >>>>
> >>>
> >>
>
>