[Libguestfs] virt-v2v F18 guest on F18 failure

[Richard W.M. Jones]

On Thu, Feb 28, 2013 at 08:15:08AM -0700, Ryan Barry wrote:
> Run with LIBGUESTFS_ATTACH_METHOD=appliance 
> 
> Fails with: 
> 
> inspect_os: mount_ro: /dev/sda on / (options: 'ro'): mount: /dev/sda is already mounted or /sysroot busy at 
>       /usr/share/perl5/vendor_perl/Sys/VirtConvert/GuestfsHandle.pm line 194.

util-linux prints this when the mount syscall returns -EBUSY.

The man page for mount(2) gives these reasons:

EBUSY
  source is already mounted.
  [probably not]

  Or, it cannot be remounted read-only, because it still holds files
  open for writing.
  [while we are mounting r/o, we're not *re*mounting, and in any case
  we shouldn't have any files open for write]

  Or, it cannot be mounted on target because target is still busy (it
  is the working directory of some thread, the mount point of another
  device, has open files, etc.).
  [Could some other process have /sysroot open?  The only candidate
  is udev.]

I also looked at the Linux kernel code to see if there are any other
reasons why do_mount would return -EBUSY.  The only obvious ones are:

 - remounting read-only with files open for write

 - mounting the same filesystem a second time on the same mountpoint

 - mountpoint has open files, current working directories, chroots
   or sub-mounts

None of these seem as if they are likely reasons.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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