With mvflt.ko module, move-in operation failed on CentOS 7

[tohosys]

Dear @slavaim,

Threre is OS version problem during move-in test with mvflt sample module.
On the CentOS 6.4, rename_in callback captures move-in operation, successfully.
But on the CentOS 7.6, move-in operation failed. mv command be hung.

dmesg log:

2월 13 10:17:12 drbd9-01 kernel: INFO: task mv:44495 blocked for more than 120 seconds.
2월 13 10:17:12 drbd9-01 kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
2월 13 10:17:12 drbd9-01 kernel: mv D ffff8b18d9dcb200 0 44495 21987 0x00000080
2월 13 10:17:12 drbd9-01 kernel: Call Trace:
2월 13 10:17:12 drbd9-01 kernel: [] schedule_preempt_disabled+0x29/0x70
2월 13 10:17:12 drbd9-01 kernel: [] __mutex_lock_slowpath+0xc7/0x1d0
2월 13 10:17:12 drbd9-01 kernel: [] mutex_lock+0x1f/0x2f
2월 13 10:17:12 drbd9-01 kernel: [] rfs_dcache_walk+0xaf/0x2a0 [redirfs]
2월 13 10:17:12 drbd9-01 kernel: [] ? kmem_cache_alloc_trace+0x1d6/0x200
2월 13 10:17:12 drbd9-01 kernel: [] ? rfs_dcache_add_dir+0x40/0x40 [redirfs]
2월 13 10:17:12 drbd9-01 kernel: [] rfs_info_add+0x36/0x80 [redirfs]
2월 13 10:17:12 drbd9-01 kernel: [] rfs_fsrename+0x497/0x670 [redirfs]
2월 13 10:17:12 drbd9-01 kernel: [] rfs_rename+0x27d/0x3e0 [redirfs]
2월 13 10:17:12 drbd9-01 kernel: [] ? legitimize_mnt+0x16/0x40
2월 13 10:17:12 drbd9-01 kernel: [] ? mutex_lock+0x12/0x2f
2월 13 10:17:12 drbd9-01 kernel: [] vfs_rename+0x82d/0x880
2월 13 10:17:12 drbd9-01 kernel: [] SYSC_renameat2+0x503/0x5a0
2월 13 10:17:12 drbd9-01 kernel: [] ? system_call_after_swapgs+0xae/0x146
2월 13 10:17:12 drbd9-01 kernel: [] ? system_call_after_swapgs+0xa2/0x146
2월 13 10:17:12 drbd9-01 kernel: [] ? system_call_after_swapgs+0xae/0x146
2월 13 10:17:12 drbd9-01 kernel: [] ? system_call_after_swapgs+0xa2/0x146
2월 13 10:17:12 drbd9-01 kernel: [] ? system_call_after_swapgs+0xae/0x146
2월 13 10:17:12 drbd9-01 kernel: [] ? system_call_after_swapgs+0xa2/0x146
2월 13 10:17:12 drbd9-01 kernel: [] SyS_renameat2+0xe/0x10
2월 13 10:17:12 drbd9-01 kernel: [] system_call_fastpath+0x22/0x27
2월 13 10:17:12 drbd9-01 kernel: [] ? system_call_after_swapgs+0xae/0x146

Thanks.