This issue also can be reproduce with virt-v2v-0.7.1-2.el5+ libguestfs-1.2.7-1.el5.13

+++ This bug was initially created as a clone of Bug #702007 +++

Description of problem:
v2v fails to remove the mounted export domain when the guest has multiboot OSes.

Version-Release number of selected component (if applicable):
virt-v2v-0.7.1-4.el6.x86_64
libguestfs-1.7.17-15.el6.x86_64

How reproducible:
always

Steps to Reproduce:
1.# pwd
/

2.# virt-v2v -ic qemu+ssh://10.66.72.122/system  -o rhev -op 10.66.90.115:/vol/v2vrwu1/yuping_export kvm-rhel5.7-but-grub-in-rhel6.1
kvm-rhel5.7-but-grub-in-rhel6.1: 100% [================================================]D 0h03m22s
unknown filesystem label SWAP-hda2
virt-v2v: multiboot operating systems are not supported by virt-v2v
rm: cannot remove `/tmp/RTVPEl5RBV/47903277-f279-406d-b0f9-b8d9d5f0a504/v2v.F0s3XQGL/10f629a3-024f-427f-afb4-9389f758361e': Directory not empty
virt-v2v: Error whilst attempting to remove temporary directory /tmp/RTVPEl5RBV/47903277-f279-406d-b0f9-b8d9d5f0a504/v2v.F0s3XQGL
virt-v2v: Failed to unmount 10.66.90.115:/vol/v2vrwu1/yuping_export. Command exited with status 16. Output was: umount.nfs: /tmp/RTVPEl5RBV: device is busy
umount.nfs: /tmp/RTVPEl5RBV: device is busy

virt-v2v: Failed to remove mount directory /tmp/RTVPEl5RBV: Device or resource busy

3.# echo $?
17

4.# mount
/dev/mapper/vg_RHEL6_x64-LogVol00 on / type ext4 (rw)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
tmpfs on /dev/shm type tmpfs (rw)
/dev/sda2 on /boot type ext4 (rw)
none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
/tmp on /tmp type none (rw,bind)
/var/tmp on /var/tmp type none (rw,bind)
/home on /home type none (rw,bind)
sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)
10.66.90.115:/vol/v2vrwu1/rwu_export on /tmp/G8Ql_gf3E5 type nfs (rw,addr=10.66.90.115)
10.66.90.115:/vol/v2vrwu1/yuping_export on /tmp/RTVPEl5RBV type nfs (rw,addr=10.66.90.115)

  
Actual results:
As step3 mentioned

Expected results:
Remove mount tmp dir successfully.

Additional info: