Clarification need on Keil RL Flash file system

Hello Team,

Good day! 

In one of our product we are using keil RL Flash file system, file system crash has observed during the file creation and file rename operation.  Please let us know the reason to cause file system crash.

One more observation has found in file rename operation.  During the file rename operation, file lock status checking is there to check the file status, sometimes file has locked due to this problem file rename is not happening successfully.  Please clarify me of following questions,

1) What is the purpose of  fs_efs_lock function in file create and file rename operation?

2) Is this necessary to have in file rename function?

3) What is causing file rename failure other than above operation?

Please let me know your solution and suggestion as soon as possible.  If you need any other details or queries, please let me know.

Regards,

Saranbabu KM