[#LU-14509] Close request can't be sent

PID: 17991  TASK: ffff918fa0168000  CPU: 1   COMMAND: "cp"
 #0 [ffff918f93083878] __schedule at ffffffff98969b97
 #1 [ffff918f93083900] schedule at ffffffff9896a099
 #2 [ffff918f93083910] obd_get_mod_rpc_slot at ffffffffc10b46fd [obdclass]
 #3 [ffff918f930839b0] ptlrpc_get_mod_rpc_slot at ffffffffc1368ffe [ptlrpc]
 #4 [ffff918f930839d0] mdc_close at ffffffffc161dd07 [mdc]
 #5 [ffff918f93083a28] lmv_close at ffffffffc166008e [lmv]
 #6 [ffff918f93083a68] ll_close_inode_openhandle at ffffffffc1698fb7 [lustre]
 #7 [ffff918f93083ad0] ll_release_openhandle at ffffffffc16a3acf [lustre]
 #8 [ffff918f93083b00] ll_file_open at ffffffffc16a4fa5 [lustre]
 #9 [ffff918f93083bb0] do_dentry_open at ffffffff9843eada
#10 [ffff918f93083bf8] finish_open at ffffffff9843ec3f
#11 [ffff918f93083c10] ll_atomic_open at ffffffffc16cf45c [lustre]
#12 [ffff918f93083cd0] do_last at ffffffff98450023
#13 [ffff918f93083d70] path_openat at ffffffff984529e2
#14 [ffff918f93083e08] do_filp_open at ffffffff9845407d
#15 [ffff918f93083ee0] do_sys_open at ffffffff984401a7

There is a slot for close request but close thread can't be woken up due to exclusive wait.

crash> obd_device 0xffff918fa1a20000
...   
      cl_max_mod_rpcs_in_flight = 7,
      cl_mod_rpcs_in_flight = 7,
      cl_close_rpcs_in_flight = 0,

[LU-14509] Close request can't be sent Created: 10/Mar/21 Updated: 10/Mar/21 Resolved: 10/Mar/21
Status:	Closed
Project:	Lustre
Component/s:	None
Affects Version/s:	None
Fix Version/s:	None

[LU-14509] Close request can't be sent Created: 10/Mar/21 Updated: 10/Mar/21 Resolved: 10/Mar/21