SingleFileStore continues to consume space on the disk even if the free entries at end of the file are not in use. This space can be released back to the filesystem

We are testing the latest Infinispan 6.0 SingleFileStore version for our application.
We tend to create a lot of entries in the store and remove them when not required.
However, what we have observed is that the size of the file keeps on increasing as more data is being added/removed and that it does not get reclaimed.

This was not seen with earlier versions like 5.3.0. There the size of the cache folder would reduce as entries got removed.

We have attempted to create a fix for this issue and tested it in our environment. It keeps the space usage under control as compared to the original implementation.

As a part of this fix, we truncate the file (as a part of purge cycle) if there are free entries found towards the end of the file. Also these free entries are removed from the freeList.