vfs_lock_file – file byte range lock

1. vfs_lock_file – file byte range lock

2. Manual

 int vfs_lock_file(struct file * filp, unsigned int cmd, struct file_lock * fl, struct file_lock * conf);

 filp
           The file to apply the lock to

       cmd
           type of locking operation (F_SETLK, F_GETLK, etc.)

       fl
           The lock to be applied

       conf
           Place to return a copy of the conflicting lock, if found.