+++ This bug was initially created as a clone of Bug #822485 +++

Description of problem:

2 replica volume. Started running bonnie on the fuse mount point, and did graph changes. glusterfs client crashed with the below backtrace.

Core was generated by `/usr/local/sbin/glusterfs --volfile-id=vol --volfile-server=hyperspace /mnt/cli'.
Program terminated with signal 11, Segmentation fault.
#0  0x00007f399b6798e5 in __fd_ctx_set (fd=0x20aae7c, xlator=0x1fb0b20, value=34359456) at ../../../libglusterfs/src/fd.c:803
803	                new_xl_count = fd->xl_count + xlator->graph->xl_count;
(gdb) bt
#0  0x00007f399b6798e5 in __fd_ctx_set (fd=0x20aae7c, xlator=0x1fb0b20, value=34359456) at ../../../libglusterfs/src/fd.c:803
#1  0x00007f3999156d4d in __fuse_fd_ctx_check_n_create (this=0x1fb0b20, fd=0x20aae7c)
    at ../../../../../xlators/mount/fuse/src/fuse-bridge.c:43
#2  0x00007f3999156e06 in fuse_fd_ctx_check_n_create (this=0x1fb0b20, fd=0x20aae7c) at ../../../../../xlators/mount/fuse/src/fuse-bridge.c:67
#3  0x00007f399916c23e in fuse_handle_opened_fds (this=0x1fb0b20, old_subvol=0x2043340, new_subvol=0x7f3988016960)
    at ../../../../../xlators/mount/fuse/src/fuse-bridge.c:3681
#4  0x00007f399916c31f in fuse_graph_switch_task (data=0x202ebe0) at ../../../../../xlators/mount/fuse/src/fuse-bridge.c:3725
#5  0x00007f399b68e0cd in synctask_wrap (old_task=0x2032180) at ../../../libglusterfs/src/syncop.c:126
#6  0x00007f399a8fd1a0 in ?? () from /lib/x86_64-linux-gnu/libc.so.6
#7  0x0000000000000000 in ?? ()
(gdb) f 0
#0  0x00007f399b6798e5 in __fd_ctx_set (fd=0x20aae7c, xlator=0x1fb0b20, value=34359456) at ../../../libglusterfs/src/fd.c:803
803	                new_xl_count = fd->xl_count + xlator->graph->xl_count;
(gdb) p xlator->graph
$1 = (glusterfs_graph_t *) 0x0
(gdb) f 0
#0  0x00007f399b6798e5 in __fd_ctx_set (fd=0x20aae7c, xlator=0x1fb0b20, value=34359456) at ../../../libglusterfs/src/fd.c:803
803	                new_xl_count = fd->xl_count + xlator->graph->xl_count;
(gdb) p xlator->graph
$1 = (glusterfs_graph_t *) 0x0
(gdb) info thr
  7 Thread 8810  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:162
  6 Thread 8800  0x00007f399a99e6a3 in epoll_wait () at ../sysdeps/unix/syscall-template.S:82
  5 Thread 8801  do_sigwait (set=<value optimized out>, sig=0x7f399914ceb8)
    at ../nptl/sysdeps/unix/sysv/linux/../../../../../sysdeps/unix/sysv/linux/sigwait.c:65
  4 Thread 8811  0x00007f399afe9cbd in read () at ../sysdeps/unix/syscall-template.S:82
  3 Thread 8802  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:162
  2 Thread 8807  0x00007f399afea4bd in nanosleep () at ../sysdeps/unix/syscall-template.S:82
* 1 Thread 8803  0x00007f399b6798e5 in __fd_ctx_set (fd=0x20aae7c, xlator=0x1fb0b20, value=34359456) at ../../../libglusterfs/src/fd.c:803
(gdb) p *xl
No symbol "xl" in current context.
(gdb) p *xlator
$2 = {name = 0x1fb03a0 "fuse", type = 0x1fb06f0 "mount/fuse", next = 0x0, prev = 0x0, parents = 0x0, children = 0x0, 
  options = 0x7f399955c04c, dlhandle = 0x1fb14c0, fops = 0x7f39993781a0, cbks = 0x7f3999378440, dumpops = 0x7f3999378120, volume_options = {
    next = 0x1fb1a10, prev = 0x1fb1a10}, fini = 0x7f399916e83b <fini>, init = 0x7f399916d9ea <init>, reconfigure = 0, 
  mem_acct_init = 0x7f399916d80a <mem_acct_init>, notify = 0x7f399916d4b1 <notify>, loglevel = GF_LOG_NONE, latencies = {{min = 0, max = 0, 
      total = 0, std = 0, mean = 0, count = 0} <repeats 46 times>}, history = 0x0, ctx = 0x1f93010, graph = 0x0, itable = 0x0, 
  init_succeeded = 1 '\001', private = 0x1fb2770, mem_acct = {num_types = 98, rec = 0x1fb1b00}, winds = 0, switched = 0 '\000', 
  local_pool = 0x0}
(gdb) 



Version-Release number of selected component (if applicable):


How reproducible:


Steps to Reproduce:
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Actual results:


Expected results:


Additional info:

 gluster volume info vol
 
Volume Name: vol
Type: Replicate
Volume ID: 08835951-9500-47fa-9c2d-4868a8d96736
Status: Started
Number of Bricks: 1 x 2 = 2
Transport-type: tcp
Bricks:
Brick1: hyperspace:/mnt/sda8/export6
Brick2: hyperspace:/mnt/sda10/export3
Options Reconfigured:
features.limit-usage: /:22GB
features.quota: on
diagnostics.count-fop-hits: on
diagnostics.latency-measurement: on
performance.stat-prefetch: off
root@hyperspace:/home/raghu#