Description of problem: While creating a file from the fuse mount in a loop and reading the file from the nfs client, the read returns EIO sometimes. This behaviour wasn't seen when io-cache was disabled. The op_errno value is reset in io-cache.


How reproducible: Often


Steps to Reproduce:
1. while true; do echo 'sdsds' > /mnt/fuse/dot; done
2. while true; do cat /mnt/nfs/dot; done


Actual results: EIO is returned


Additional info:


gdb) bt
#0  nfs3svc_read_cbk (frame=0x7fc252647008, cookie=0x19f8860, this=0x19f9a80, op_ret=0, op_errno=0, vector=0x1a07ac0, count=0, stbuf=0x7fff5e819720,
    iobref=0x1a08ab0) at nfs3.c:1773
#1  0x00007fc2501ca4ca in nfs_fop_readv_cbk (frame=0x7fc252647008, cookie=0x19f8860, this=0x19f9a80, op_ret=0, op_errno=0, vector=0x1a07ac0, count=0,
    stbuf=0x7fff5e819720, iobref=0x1a08ab0) at nfs-fops.c:1329
#2  0x00007fc250419a39 in io_stats_readv_cbk (frame=0x7fc25368e4e0, cookie=0x7fc25368e58c, this=0x19f8860, op_ret=0, op_errno=0, vector=0x1a07ac0, count=0,
    buf=0x7fff5e819720, iobref=0x1a08ab0) at io-stats.c:1332
#3  0x00007fc25063b66a in ioc_frame_unwind (frame=0x7fc25368e58c) at page.c:870
#4  0x00007fc25063b8f7 in ioc_frame_return (frame=0x7fc25368e58c) at page.c:912
#5  0x00007fc250639b31 in ioc_waitq_return (waitq=0x1a07960) at page.c:410
#6  0x00007fc25063a1dd in ioc_fault_cbk (frame=0x7fc2526467e4, cookie=0x7fc25368e638, this=0x19f76f0, op_ret=0, op_errno=2, vector=0x7fff5e819a00, count=1,
    stbuf=0x7fff5e819bd0, iobref=0x1a08790) at page.c:535
#7  0x00007fc25086495d in afr_readv_cbk (frame=0x7fc25368e638, cookie=0x0, this=0x19f65a0, op_ret=0, op_errno=2, vector=0x7fff5e819a00, count=1, 
    buf=0x7fff5e819bd0, iobref=0x1a08790) at afr-inode-read.c:1228
#8  0x00007fc250aeb00b in client3_1_readv_cbk (req=0x7fc2497128e8, iov=0x7fc249712928, count=2, myframe=0x7fc25368e388) at client3_1-fops.c:2252
#9  0x00007fc254e2c1bf in rpc_clnt_handle_reply (clnt=0x1a047f0, pollin=0x19efda0) at rpc-clnt.c:796
#10 0x00007fc254e2c536 in rpc_clnt_notify (trans=0x1a04a50, mydata=0x1a04820, event=RPC_TRANSPORT_MSG_RECEIVED, data=0x19efda0) at rpc-clnt.c:915
#11 0x00007fc254e28230 in rpc_transport_notify (this=0x1a04a50, event=RPC_TRANSPORT_MSG_RECEIVED, data=0x19efda0) at rpc-transport.c:498
#12 0x00007fc24e5bf323 in socket_event_poll_in (this=0x1a04a50) at socket.c:1686
#13 0x00007fc24e5bf88c in socket_event_handler (fd=6, idx=4, data=0x1a04a50, poll_in=1, poll_out=0, poll_err=0) at socket.c:1801
#14 0x00007fc25508242c in event_dispatch_epoll_handler (event_pool=0x19eb500, events=0x1a062c0, i=0) at event.c:794
#15 0x00007fc25508263f in event_dispatch_epoll (event_pool=0x19eb500) at event.c:856
#16 0x00007fc2550829b2 in event_dispatch (event_pool=0x19eb500) at event.c:956
#17 0x0000000000407f1e in main (argc=7, argv=0x7fff5e81a128) at glusterfsd.c:1601