Description of problem:

The following crash is seen when getfacl is done on a file and stat on the file fails for any reason:

#0  0x00007f8b80989dbd in acl3_stat_cbk (frame=<optimized out>, cookie=<optimized out>, this=<optimized out>, op_ret=<optimized out>, op_errno=13, buf=<optimized out>, xdata=0x0)
    at ../../../../../xlators/nfs/server/src/acl3.c:307
#1  0x00007f8b8095f182 in STACK_DESTROY (stack=0xd) at ../../../../../libglusterfs/src/stack.h:174
#2  nfs_fop_fstat_cbk (frame=<optimized out>, cookie=<optimized out>, this=<optimized out>, op_ret=<optimized out>, op_errno=<optimized out>, buf=<optimized out>, xdata=0x0)
    at ../../../../../xlators/nfs/server/src/nfs-fops.c:552
#3  0x00007f8b80bb35fb in io_stats_stat_cbk (frame=0x7f8b840c258c, cookie=<optimized out>, this=<optimized out>, op_ret=-1, op_errno=13, buf=0x0, xdata=0x0)
    at ../../../../../xlators/debug/io-stats/src/io-stats.c:1311
#4  0x00007f8b80dc88db in error_gen_stat (frame=0x7f8b840c2638, this=<optimized out>, loc=<optimized out>, xdata=0x0) at ../../../../../xlators/debug/error-gen/src/error-gen.c:444
#5  0x00007f8b80ba979d in io_stats_stat (frame=0x7f8b840c258c, this=0x201cd00, loc=0x7f8b7a1de414, xdata=0x0) at ../../../../../xlators/debug/io-stats/src/io-stats.c:1877
#6  0x00007f8b80960423 in nfs_fop_stat (nfsx=<optimized out>, xl=0x201cd00, nfu=<optimized out>, loc=0x7f8b7a1de414, cbk=0x7f8b80989c50 <acl3_getacl_resume+344>, local=0x7f8b7a1de02c)
    at ../../../../../xlators/nfs/server/src/nfs-fops.c:526
#7  0x00007f8b80989afd in acl3_getacl_resume (carg=0x7f8b7a1de02c) at ../../../../../xlators/nfs/server/src/acl3.c:324
#8  0x00007f8b8506a488 in ?? () from /usr/local/lib/libgfrpc.so.0
#9  0x0000000000000000 in ?? ()


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

How reproducible:
Always


Steps to Reproduce:
1. Perform getfacl on a file from nfs mount
2. Ensure that stat on the object fails by unlinking the file from a different client.
3. NFS server crashes
  
Actual results:

NFS server should not crash.


Expected results:


Additional info: