Lock release for write fails on Cori with more than 1 client

[QiaoK]

To reproduce, follow my steps to install PDC on Cori. Then goto the bin folder in the install folder. Run the following. You can see the segmentation fault.
./mpi_test.sh ./write_obj srun 1 2 o 1 int

qkt561@nid00009:/global/cscratch1/sd/qkt561/FS_1M_169/bin> ./mpi_test.sh ./write_obj srun 1 2 o 1 int
Input arguments are the followings
o 1 int
testing: ./write_obj
srun -n 1 ./pdc_server.exe &
srun -n 2 ./write_obj o 1 int
Writing a 1 MB object [o_0] with 2 clients.
Writing a 1 MB object [o_1] with 2 clients.
==PDC_CLIENT: PDC_DEBUG set to 0!
==PDC_CLIENT[0]: Config file from default location [./pdc_tmp/server.cfg] not available, waiting 1 seconds
==PDC_CLIENT[0]: Config file from default location [./pdc_tmp/server.cfg] not available, waiting 2 seconds
==PDC_CLIENT[0]: Config file from default location [./pdc_tmp/server.cfg] not available, waiting 4 seconds
==PDC_CLIENT[0]: Config file from default location [./pdc_tmp/server.cfg] not available, waiting 8 seconds
Unidentified node: Error detected by libibgni.so.  Subsequent operation may be unreliable.  IAA did not recognize this as an MPI process
Unidentified node: Error detected by libibgni.so.  Subsequent operation may be unreliable.  IAA did not recognize this as an MPI process

==PDC_SERVER[0]: using [./pdc_tmp/] as tmp dir. 0 OSTs per data file, 0% to BB
==PDC_SERVER[0]: using ofi+tcp
==PDC_SERVER[0]: without multi-thread!
==PDC_SERVER[0]: Read cache enabled!
==PDC_SERVER[0]: Successfully established connection to 0 other PDC servers
==PDC_SERVER[0]: Server ready!


==PDC_CLIENT[0]: Found 1 PDC Metadata servers, running with 2 PDC clients
==PDC_CLIENT: using ofi+tcp
Unidentified node: Error detected by libibgni.so.  Subsequent operation may be unreliable.  IAA did not recognize this as an MPI process
Unidentified node: Error detected by libibgni.so.  Subsequent operation may be unreliable.  IAA did not recognize this as an MPI process
==PDC_CLIENT[0]: Client lookup all servers at start time!
Unidentified node: Error detected by libibgni.so.  Subsequent operation may be unreliable.  IAA did not recognize this as an MPI process
Unidentified node: Error detected by libibgni.so.  Subsequent operation may be unreliable.  IAA did not recognize this as an MPI process
==PDC_CLIENT[0]: using [./pdc_tmp] as tmp dir, 2 clients per server
create a new pdc
create a new pdc
my_data_size at rank 0 is 524288
my_data_size at rank 1 is 524288
rank 0 offset = 0, length = 524288, unit size = 4
rank 1 offset = 524288, length = 524288, unit size = 4
Error in /global/homes/q/qkt561/test_install/pdc/src/api/pdc_client_server_common.c:1946
 # buf_map_region_release_bulk_transfer_cb(): Error in region_release_bulk_transfer_cb()
srun: error: nid00009: task 0: Segmentation fault
srun: Terminating job step 40407325.8
srun: error: nid00009: task 1: Segmentation fault
srun: Terminating job step 40407325.7
slurmstepd: error: *** STEP 40407325.7 ON nid00009 CANCELLED AT 2021-03-07T18:38:44 ***
srun: error: nid00009: task 0: Killed
srun: Force Terminated job step 40407325.7
==PDC_CLIENT: PDC_DEBUG set to 0!
==PDC_CLIENT[0]: Found 1 PDC Metadata servers, running with 1 PDC clients
==PDC_CLIENT: using ofi+tcp
Unidentified node: Error detected by libibgni.so.  Subsequent operation may be unreliable.  IAA did not recognize this as an MPI process
Unidentified node: Error detected by libibgni.so.  Subsequent operation may be unreliable.  IAA did not recognize this as an MPI process
==PDC_CLIENT[0]: Client lookup all servers at start time!
srun: error: nid00009: task 0: Segmentation fault
srun: Terminating job step 40407325.9

[houjun]

Fixed the test code, the mapping should use local offset (all ranks use 0), and global offset (differ in different ranks) for buffer mapping, and the lock and release should use "global_region" instead of "local_region".