Description of problem:
So it all started with nfs-ganesha not coming up.
Basically in order to bring up nfs-ganesha I used cli command introduced recently in the glusterfs builds.
The mechanism is that is if glusterfs-nfs is already running then it will disable it and bring up nfs-ganesha. So during this phase some registering/deregistering related issue happened with port 875, which actually gets used by RQUOTA as privileged port.

Version-Release number of selected component (if applicable):
glusterfs-3.7.0beta1-0.69.git1a32479.el6.x86_64
nfs-ganesha-2.2.0-0.el6.x86_64

How reproducible:
Intermittent

Steps to Reproduce:
1. create a volume of 6x2 type.
2. do all the pre-requisites for nfs-ganesha
3. gluster nfs-ganesha enable

Actual results:
the nfs-ganesha does not come up,

Intitally the nfs-ganesha logs suggested that the issue is with rpcbind as can be seen from the logs,
12/05/2015 12:29:55 : epoch 5551a4eb : nfs1 : ganesha.nfsd-32374[main] main :MAIN :EVENT :ganesha.nfsd Starting: Ganesha Version /builddir/build/BUILD/nfs-ganesha-2.2.0-0.1.1-Source, built at Apr 28 2015 09:
45:22 on i-0003a944
12/05/2015 12:29:55 : epoch 5551a4eb : nfs1 : ganesha.nfsd-32375[main] nfs_set_param_from_conf :NFS STARTUP :EVENT :Configuration file successfully parsed
12/05/2015 12:29:55 : epoch 5551a4eb : nfs1 : ganesha.nfsd-32375[main] init_server_pkgs :NFS STARTUP :EVENT :Initializing ID Mapper.
12/05/2015 12:29:55 : epoch 5551a4eb : nfs1 : ganesha.nfsd-32375[main] init_server_pkgs :NFS STARTUP :EVENT :ID Mapper successfully initialized.
12/05/2015 12:29:55 : epoch 5551a4eb : nfs1 : ganesha.nfsd-32375[main] main :NFS STARTUP :WARN :No export entries found in configuration file !!!
12/05/2015 12:29:55 : epoch 5551a4eb : nfs1 : ganesha.nfsd-32375[main] config_errs_to_log :CONFIG :WARN :Config File ((null):0): Empty configuration file
12/05/2015 12:29:55 : epoch 5551a4eb : nfs1 : ganesha.nfsd-32375[main] lower_my_caps :NFS STARTUP :EVENT :CAP_SYS_RESOURCE was successfully removed for proper quota management in FSAL
12/05/2015 12:29:55 : epoch 5551a4eb : nfs1 : ganesha.nfsd-32375[main] lower_my_caps :NFS STARTUP :EVENT :currenty set capabilities are: = cap_chown,cap_dac_override,cap_dac_read_search,cap_fowner,cap_fsetid
,cap_kill,cap_setgid,cap_setuid,cap_setpcap,cap_linux_immutable,cap_net_bind_service,cap_net_broadcast,cap_net_admin,cap_net_raw,cap_ipc_lock,cap_ipc_owner,cap_sys_module,cap_sys_rawio,cap_sys_chroot,cap_sys
_ptrace,cap_sys_pacct,cap_sys_admin,cap_sys_boot,cap_sys_nice,cap_sys_time,cap_sys_tty_config,cap_mknod,cap_lease,cap_audit_write,cap_audit_control,cap_setfcap+ep
12/05/2015 12:29:55 : epoch 5551a4eb : nfs1 : ganesha.nfsd-32375[main] Bind_sockets_V6 :DISP :WARN :Cannot bind RQUOTA tcp6 socket, error 98 (Address already in use)
12/05/2015 12:29:55 : epoch 5551a4eb : nfs1 : ganesha.nfsd-32375[main] Bind_sockets :DISP :FATAL :Error binding to V6 interface. Cannot continue.

But after root cause it seems the issue is related as described in description section. 

Expected results:
NFS-ganesha has to come up seamleslly and clean up post nfs.disable should be proper, ports required for nfs-ganesha to come up should be available.

Additional info: