Size of logical volume pve/vm-107-disk-1 changed from 80.00 GiB (20480 extents) to 100.00 GiB (25600 extents).
Logical volume pve/vm-107-disk-1 successfully resized.
resize2fs 1.43.4 (31-Jan-2017)
resize2fs: Permission denied to resize filesystem
Filesystem at /dev/pve/vm-107-disk-1 is mounted on /tmp; on-line resizing required
old_desc_blocks = 5, new_desc_blocks = 7
Failed to update the container's filesystem: command 'unshare -m -- sh -c 'mount --make-rprivate / && mount /dev/pve/vm-107-disk-1 /tmp && resize2fs /dev/pve/vm-107-disk-1'' failed: exit code 1
Proxmox VE 4.1
Using the gui to resize a disk shows that it resized but failed. Most like this is due to erros in the underlying file system within the container. The fix....
# pct fsck 107
# pct mount 107
# resize2fs /var/lib/lxc/107/rootfs
# pct unmount 107