End-to end checksum data

[drbasic]

It is necessary to check the checksums of the data that is being read and written.

1. When receiving write data from the client, you need to calculate the checksum and make sure that data with the same checksum is written to disk.
2. When reading data, you need to know (or at least calculate the checksum) and verify this checksum before giving the data to the client.

[drbasic]

At the first stage, we calculate the checksum of the buffer of data received from the client before the start of writing and after the data is written. If the checksum has changed, it means that the client is spoiling the buffer and it is necessary to repeat the writing, having previously copied the buffer to another location.
#2985