`ls` for NFS volume fails with "Input/output error" and NFS server shows "nfsd: non-standard errno: -29"

Issue

• ls fails with the follwoing message.

ls: reading directory /mnt/nfs: Input/output error

• NFS server shows the following messages.

------------[ cut here ]------------
WARNING: at fs/nfsd/nfsproc.c:804 nfserrno+0x58/0x70 [nfsd]()
nfsd: non-standard errno: -29
Modules linked in: splxmod(OE) ip6t_rpfilter ipt_REJECT nf_reject_ipv4 ip6t_REJECT nf_reject_ipv6 xt_conntrack ebtable_nat ebtable_broute ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6table_mangle ip6table_security ip6table_raw iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack iptable_mangle iptable_security iptable_raw ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter ip_tables loop nfnetlink_queue nfnetlink_log bluetooth rfkill nls_utf8 isofs pmfs(OE) ip_set nfnetlink bridge stp llc intel_powerclamp coretemp crc32_pclmul ghash_clmulni_intel ppdev aesni_intel lrw gf128mul glue_helper ablk_helper cryptd vmw_balloon pcspkr sg vmw_vmci i2c_piix4 shpchp parport_pc parport nfsd auth_rpcgss nfs_acl lockd grace binfmt_misc sunrpc ext4
 mbcache jbd2 sr_mod cdrom ata_generic pata_acpi sd_mod crc_t10dif crct10dif_generic vmwgfx crct10dif_pclmul crct10dif_common crc32c_intel drm_kms_helper ahci serio_raw syscopyarea sysfillrect sysimgblt fb_sys_fops ttm vmxnet3 libahci drm ata_piix libata vmw_pvscsi i2c_core floppy fjes dm_mirror dm_region_hash dm_log dm_mod [last unloaded: splxmod]
CPU: 0 PID: 1515 Comm: nfsd Tainted: G        W  OE  ------------   3.10.0-514.16.1.el7.x86_64 #1
Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 07/30/2013
 ffff8800ba737cb0 0000000039ce94c9 ffff8800ba737c68 ffffffff816869c3
 ffff8800ba737ca0 ffffffff81085cb0 ffff88032566f294 0000000000000000
 ffffffffa0378e80 ffff88032566f008 0000000000000000 ffff8800ba737d08
Call Trace:
 [<ffffffff816869c3>] dump_stack+0x19/0x1b
 [<ffffffff81085cb0>] warn_slowpath_common+0x70/0xb0
 [<ffffffffa0378e80>] ? nfs3svc_encode_entry+0x20/0x20 [nfsd]
 [<ffffffff81085d4c>] warn_slowpath_fmt+0x5c/0x80
 [<ffffffffa03696d8>] nfserrno+0x58/0x70 [nfsd]
 [<ffffffffa036e18f>] nfsd_readdir+0x1cf/0x200 [nfsd]
 [<ffffffffa03755ed>] nfsd3_proc_readdirplus+0x12d/0x280 [nfsd]
 [<ffffffffa03676fb>] nfsd_dispatch+0xbb/0x200 [nfsd]
 [<ffffffffa0309ea3>] svc_process_common+0x453/0x6f0 [sunrpc]
 [<ffffffffa030a24b>] svc_process+0x10b/0x1a0 [sunrpc]
 [<ffffffffa036707f>] nfsd+0xdf/0x150 [nfsd]
 [<ffffffffa0366fa0>] ? nfsd_destroy+0x80/0x80 [nfsd]
 [<ffffffff810b0a4f>] kthread+0xcf/0xe0
 [<ffffffff810b0980>] ? kthread_create_on_node+0x140/0x140
 [<ffffffff81696fd8>] ret_from_fork+0x58/0x90
 [<ffffffff810b0980>] ? kthread_create_on_node+0x140/0x140
---[ end trace 158e05723357552a ]---