Write/write conflicts are easily detected. When a client wishes to send an updated
file to the server, then the server simply checks the associated modification time
() with that of the primary copy (). If then there is
a conflict. Conflicting files are never send to the server. Of course, the server
also has to check if the file is locked (by other clients).
The only way for a client to make absolutely sure that updating to a file will
succeed is to obtain a writelock on the file, close the file and get in contact
with the server before the writelock expires!