[Libguestfs] Mounting disk images with ext2 filesystems on RHEL7

[Leonard Basuino]

On Wed, Feb 18, 2015 at 4:51 AM, Pino Toscano <ptoscano at redhat.com> wrote:

> In data martedì 17 febbraio 2015 13:37:55, Leonard Basuino ha scritto:
> > On Mon, Feb 16, 2015 at 6:10 PM, Richard W.M. Jones <rjones at redhat.com>
> > wrote:
> >
> > > On Mon, Feb 16, 2015 at 06:00:06PM -0500, Leonard Basuino wrote:
> > > > Hope someone can point me in the right direction.  I don't know if
> what I
> > > > am trying to do should work or not.
> > > >
> > > > I have 2 disk images.  One is a VM with an ext2 boot filesystem and
> ext4
> > > > filesystems with the OS loaded.  I am amble to guestmount this with
> no
> > > > issue and am able to see the files that are on the ext2 file system.
> > > >
> > > > I can also run guestfish on the image, mount the ext2 filesystem, and
> > > list
> > > > the files.
> > > >
> > > > However, the second image I have is only a boot disk image with just
> an
> > > > ext2 filesystem.
> > > >
> > > > guestmount complains that there is no OS and won't mount.
> > >
> > > What you really need to do is run:
> > >
> > >   virt-filesystems -a second-disk.img --all --long -h
> > >
> > > which will tell you what filesystems (etc) are available in the second
> > > image.
> > >
> >
> >
> > > The only filesystem is /dev/sda1 of type ext2
> >
> >
> >
> > > > guestfish complains "...wrong fs type, bad option, bad
> superblock...".
> > >
> > > Try using guestfish -v -x flags to provide extra information about
> > > this error.  See:
> > >
> > > http://libguestfs.org/guestfs-faq.1.html#debug
> > >
> >
> > I get the following debug info:
> >
> > mount -o /dev/sda1 /
> > [ <time> ] EXT4-fs (sda1): mounting ext2 file system using the ext4
> > subsystem
> > [ <time> ] EXT4-fs (sda1): bad geometry: block count 104388 exceeds size
> of
> > device (103408 blocks)
> > mount: wrong fs type, bad option, bad superblock on /dev/sda1
> > ....
>
> This might mean that the partition has been resized to a smaller size,
> but without updating the partition table. Is that the case?
>
> Can you please post the output of the guestfish command
> `sfdisk-l /dev/sda`?
>

(ok, I have to type it so pardon any typos)

Disk /dev/sda: 101 cylinders, 64 heads, 32 sectors/track
Units: cylinders of 1048576 bytes, blocks of 1024 bytes, counting from 0

   Device  Boot  Start          End     #cyls       #blocks    Id  System
/dev/sda1     *         0+       100         101-      103408    83  Linux
/dev/sda2               0             -             0                0
0  Empty
 /dev/sda3               0             -             0                0
0  Empty
 /dev/sda3               0             -             0                0
0  Empty


>
> > also, trying to mount the image with:
> > mount -t ext2 <image> <mount point>
> > returns:
> > mount: wrong fs type, bad option, bad superblock on /dev/loop0
> > ...
> > the end of dmesg has:
> > [<time>] EXT4-fs (loop0): VFS: Can't find ext4 filesystem
> >
> > This has me wondering because the debug messages from guestfish -v -x
> > indicate it is mouting ext2 with ext4.
> > EXT4-fs (sdb): mounting ext2 filesystem using the ext4 subsystem
>
> In recent (well, few years...) Linux versions the ext4 filesystems
> takes care of ext2 and ext3 versions as well, so the above message
> is correct.
>
> > So is the problem that there is no ext4 filesystem in the image and RHEL
> 7
> > is having issues with it?
>
> I'm not sure what you mean here, can you please rephrase?
>

I was wondering if the message indicated it was looking for ext4 in the
image which doesn't exist?
I verified that the same image mounts without issue on a RHEL 6 box but not
on a RHEL 7 box.

>
> Thanks,
> --
> Pino Toscano
>
> _______________________________________________
> Libguestfs mailing list
> Libguestfs at redhat.com
> https://www.redhat.com/mailman/listinfo/libguestfs
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listman.redhat.com/archives/libguestfs/attachments/20150218/177c638b/attachment.htm>