Thank you for contributing to the Bareos Project!

Currently letting multiple jobs write to a device in parallel will cause the bareos database to go out of sync with reality leading to data loss at worst. This PR improves the communication between the sd and the director so that this does not happen.

We do this by

• creating "null" jobmedia records whenever a job writes to a volume the first time, and
• by always sending the last jobmedia record to the director even if the volume we wrote to is not the current volume.

This should stop the director from recycling actually used volumes and stop the storage daemon from not sending all jobmedia records.

We also slim down the jobmedia table somewhat by always deleting all null jobmedia records whenever a job is finished.

Please check

• Short description and the purpose of this PR is present above this paragraph
• Your name is present in the AUTHORS file (optional)

If you have any questions or problems, please give a comment in the PR.

Helpful documentation and best practices

• Git Workflow
• Automatic Sourcecode Formatting
• Check your commit messages
• Boy Scout Rule

Checklist for the reviewer of the PR (will be processed by the Bareos team)

Make sure you check/merge the PR using devtools/pr-tool to have some simple automated checks run and a proper changelog record added.

General

• Is the PR title usable as CHANGELOG entry?
• Purpose of the PR is understood
• Commit descriptions are understandable and well formatted
• Check backport line
• Required backport PRs have been created

Source code quality

• Source code changes are understandable
• Variable and function names are meaningful
• Code comments are correct (logically and spelling)

Tests

• Decision taken that a test is required (if not, then remove this paragraph)
• The choice of the type of test (unit test or systemtest) is reasonable
• Testname matches exactly what is being tested
• On a fail, output of the test leads quickly to the origin of the fault