Cannot reduce logical volume due to busy device

[root@lab7-mongo-7 /]# lvdisplay /dev/vg_lab7mongo7/lv_home
--- Logical volume ---
LV Name                /dev/vg_lab7mongo7/lv_home
VG Name                vg_lab7mongo7
LV UUID                s4Cwkh-w7MX-uHRF-sA3f-T96e-AzZ3-8t8WtJ
LV Write Access        read/write
LV Status              available
# open                 1
LV Size                783.61 GiB
Current LE             200603
Segments               1
Allocation             inherit
Read ahead sectors     auto
- currently set to     256
Block device           253:2

[root@lab7-mongo-7 /]# df -hP /home
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/vg_lab7mongo7-lv_home  772G  571M  732G   1% /home

[root@lab7-mongo-7 /]# umount -l /home
[root@lab7-mongo-7 /]# df -hP /home
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/vg_lab7mongo7-lv_root   50G  2.4G   45G   6% /

So, partition is unmounted but i still cannot shrink it

[root@lab7-mongo-7 /]# resize2fs /dev/vg_lab7mongo7/lv_home 80G
resize2fs 1.41.12 (17-May-2010)
resize2fs: Device or resource busy while trying to open /dev/vg_lab7mongo7/lv_home
Couldn't find valid filesystem superblock.

[root@lab7-mongo-7 /]# e2fsck -ff /dev/vg_lab7mongo7/lv_home
e2fsck 1.41.12 (17-May-2010)
e2fsck: Device or resource busy while trying to open /dev/vg_lab7mongo7/lv_home
Filesystem mounted or opened exclusively by another program?

[root@lab7-mongo-7 /]# lsof |grep home
[root@lab7-mongo-7 /]#

What is holding the device?