+++ This bug was initially created as a clone of Bug #1245636 +++

Description of problem:
=======================
In a nfs ganesha set up,created some snapshots and activated them. cd to .snaps and any further operation on the mount point hangs thereafter.


Version-Release number of selected component (if applicable):
=============================================================
glusterfs-3.7.1-10.el6rhs.x86_64
nfs-ganesha-gluster-2.2.0-5.el6rhs.x86_64

How reproducible:
================
2/2


Steps to Reproduce:
===================
1.Created a 6x2 volume and mounted it

2.Scheduled some snapshots and activated them. 

3.cd  to .snaps from the mount point , it hangs . Further any operation on the mount point hangs 

nfs server times out for the showmount command but ganesha is still running on that server

[root@rhs-client21 ~]# ps -eaf | grep ganesha
root      5650 13568  0 17:27 pts/0    00:00:00 grep ganesha
root     14065     1  0 Jul17 ?        00:08:59 /usr/bin/ganesha.nfsd -L /var/log/ganesha.log -f /etc/ganesha/ganesha.conf -N NIV_EVENT -p /var/run/ganesha.nfsd.pid
[root@rhs-client21 ~]# 
[root@rhs-client21 ~]# 
[root@rhs-client21 ~]# 
[root@rhs-client21 ~]# showmount -e localhost
rpc mount export: RPC: Timed out

[nfs server timing out for the showmount command was reported in this bug - https://bugzilla.redhat.com/show_bug.cgi?id=1224618]

I am seeing this issue while testing snapshots in nfs ganesha set up.


Actual results:



Expected results:


Additional info:


--- Additional comment from Soumya Koduri on 2015-07-30 14:51:52 CEST ---

This issue is always reproducible. The issue here is that the lookup fop of snapview-client xlator 'svc_lookup' has the same name as one of the routines in libntirpc used by NFS-Ganesha. Hence while loading snapview xlator, the xlator->fops->lookup symbol incorrectly gets resolved to ntiprc 'svc_lookup'.



Breakpoint 1, meta_lookup (frame=0x7f7668016520, this=0x7f76480160d0, 
    loc=0x7f7668daea80, xdata=0x0) at meta.c:22
22	{
Missing separate debuginfos, use: debuginfo-install libacl-2.2.49-6.el6.x86_64 libuuid-2.17.2-12.14.el6_5.x86_64 openssl-1.0.1e-16.el6_5.7.x86_64 zlib-1.2.3-29.el6.x86_64
(gdb) bt
#0  meta_lookup (frame=0x7f7668016520, this=0x7f76480160d0, loc=0x7f7668daea80, 
    xdata=0x0) at meta.c:22
#1  0x00007f7661173a33 in syncop_lookup (subvol=0x7f76480160d0, 
    loc=0x7f7668daea80, iatt=0x0, parent=0x0, xdata_in=0x0, xdata_out=0x0)
    at syncop.c:1223
#2  0x00007f76613dc6eb in glfs_first_lookup_safe (subvol=0x7f76480160d0)
    at glfs-resolve.c:46
#3  0x00007f76613dc787 in __glfs_first_lookup (fs=0x7f7664007f70, 
    subvol=0x7f76480160d0) at glfs-resolve.c:63
#4  0x00007f76613dc7fb in __glfs_active_subvol (fs=0x7f7664007f70)
    at glfs-resolve.c:815
#5  0x00007f76613dcaff in priv_glfs_active_subvol (fs=0x7f7664007f70)
    at glfs-resolve.c:896
#6  0x00007f76613d3f00 in pub_glfs_chdir (fs=0x7f7664007f70, 
    path=0x7f76613e0e56 "/") at glfs-fops.c:3468
#7  0x00007f76615ec08b in glusterfs_create_export (fsal_hdl=0x7f7664007ca0, 
    parse_node=0x7f7664007560, err_type=0x7f7668daf210, up_ops=0x81ca00)
    at /home/skoduri/nfs-ganesha-new/src/FSAL/FSAL_GLUSTER/export.c:651
#8  0x000000000051a8e5 in fsal_commit (node=0x7f7664007560, 
    link_mem=0x7f7664002ed8, self_struct=0x7f7664002c70, err_type=0x7f7668daf210)
    at /home/skoduri/nfs-ganesha-new/src/support/exports.c:585
#9  0x0000000000548967 in proc_block (node=0x7f7664007560, item=0x821c00, 
    link_mem=0x7f7664002ed8, err_type=0x7f7668daf210)
    at /home/skoduri/nfs-ganesha-new/src/config_parsing/config_parsing.c:1377
#10 0x000000000054841f in do_block_load (blk=0x7f7664007ad0, params=0x8214c0, 
    relax=false, param_struct=0x7f7664002e08, err_type=0x7f7668daf210)
    at /home/skoduri/nfs-ganesha-new/src/config_parsing/config_parsing.c:1235
#11 0x0000000000548891 in proc_block (node=0x7f7664007ad0, item=0x821ce8, 
    link_mem=0x0, err_type=0x7f7668daf210)
    at /home/skoduri/nfs-ganesha-new/src/config_parsing/config_parsing.c:1361
#12 0x00000000005496d1 in load_config_from_node (tree_node=0x7f7664007ad0, 
    conf_blk=0x821ce0, param=0x0, unique=false, err_type=0x7f7668daf210)
    at /home/skoduri/nfs-ganesha-new/src/config_parsing/config_parsing.c:1868
#13 0x0000000000530607 in gsh_export_addexport (args=0x7f7668daf2e0, 
    reply=0x1dbf410, error=0x7f7668daf330)
    at /home/skoduri/nfs-ganesha-new/src/support/export_mgr.c:948
#14 0x00000000005430e2 in dbus_message_entrypoint (conn=0x1dbef40, 
    msg=0x1dbf250, user_data=0x822870)
    at /home/skoduri/nfs-ganesha-new/src/dbus/dbus_server.c:518
#15 0x000000366061cefe in ?? () from /lib64/libdbus-1.so.3
#16 0x0000003660610b4c in dbus_connection_dispatch () from /lib64/libdbus-1.so.3
#17 0x0000003660610dd9 in ?? () from /lib64/libdbus-1.so.3
---Type <return> to continue, or q <return> to quit---q
Quit
(gdb) f 1
#1  0x00007f7661173a33 in syncop_lookup (subvol=0x7f76480160d0, 
    loc=0x7f7668daea80, iatt=0x0, parent=0x0, xdata_in=0x0, xdata_out=0x0)
    at syncop.c:1223
1223	        SYNCOP (subvol, (&args), syncop_lookup_cbk, subvol->fops->lookup,
(gdb) p subvol->children->xlator->name
$2 = 0x7f76480134c0 "lvm_vol"
(gdb) p subvol->children->xlator->children->xlator->name
$3 = 0x7f76480131c0 "lvm_vol-snapview-client"
(gdb) p subvol->children->xlator->children->xlator->fops
$4 = (struct xlator_fops *) 0x7f763911c960
(gdb) p subvol->children->xlator->children->xlator->fop
There is no member named fop.
(gdb) p subvol->children->xlator->children->xlator->lookup
There is no member named lookup.
(gdb) p subvol->children->xlator->children->xlator->fops.lookup
$5 = (fop_lookup_t) 0x561ec8 <svc_lookup>
(gdb) p svc_lookup
$6 = {svc_lookup_result_t (svc_rec_t **, svc_vers_range_t *, rpcprog_t, 
    rpcvers_t, char *, u_int)} 0x561ec8 <svc_lookup>
(gdb) p *svc_lookup
$7 = {svc_lookup_result_t (svc_rec_t **, svc_vers_range_t *, rpcprog_t, 
    rpcvers_t, char *, u_int)} 0x561ec8 <svc_lookup>
(gdb) 


Marking these fops static fixed this issue. Fix is posted upstream -http://review.gluster.org/#/c/11805/