df command does not calculate the usage of bind mounts and tmpfs on RHEHV

Issue

• On RHEV hypervisor version 20140121.0.el6ev, df does not report all file systems correctly:

# df -ah
Filesystem                          Size  Used Avail Use% Mounted on
/dev/mapper/live-rw                 1.5G  464M  1.1G  31% /
/dev/mapper/HostVG-Config           7.8M  1.3M  6.1M  18% /config
none                                   0     0     0    - /proc/sys/fs/binfmt_misc
tmpfs                               127G   96K  127G   1% /dev/shm
/data/images                        132G  404M  125G   1% /var/lib/libvirt/images
/data/core                          132G  404M  125G   1% /var/log/core
sunrpc                                 0     0     0    - /var/lib/nfs/rpc_pipefs
rhevm.example.com:/data/iso           662G  166G  463G  27% /rhev/data-center/mnt/rhevm.example.com:_data_iso
rhevm.example.com:/export/DWI_Export  662G  166G  463G  27% /rhev/data-center/mnt/rhevm.example.com:_export_DWI__Export

• And if you specify a file system, such as /var/log, which is not listed in df -h, you get the actual information:

# df -h /var/log/
Filesystem      Size  Used Avail Use% Mounted on
-               2.0G  401M  1.5G  21% /var/log