mirror of
https://github.com/systemd/systemd.git
synced 2025-02-03 17:47:28 +03:00
b8f99e27e1
Early in journal_file_set_offline() f->header->state is tested to see if it's != STATE_ONLINE, and since there's no need to do anything if the journal isn't online, the function simply returned here. Since moving part of the offlining process to a separate thread, there are two problems here: 1. We can't simply check f->header->state, because if there is an offline thread active it may modify f->header->state. 2. Even if the journal is deemed offline, the thread responsible may still need joining, so a bare return may leak the thread's resources like its stack. To address #1, the helper journal_file_is_offlining() is called prior to accessing f->header->state. If journal_file_is_offlining() returns true, f->header->state isn't even checked, because an offlining journal is obviously online, and we'll just continue with the normal set offline code path. If journal_file_is_offlining() returns false, then it's safe to check f->header->state, because the offline_state is beyond the point of modifying f->header->state, and there's a memory barrier in the helper. If we find f->header->state is != STATE_ONLINE, then we call the idempotent journal_file_set_offline_thread_join() on the way out of the function, to join a potential lingering offline thread.
systemd - System and Service Manager
Details
General information about systemd can be found in the systemd Wiki.
Information about build requirements are provided in the README file.
Consult our NEWS file for information about what's new in the most recent systemd versions.
Please see our Contribution Guidelines for more information about filing GitHub Issues and posting GitHub Pull Requests.
When preparing patches for systemd, please follow our Coding Style Guidelines.
If you are looking for support, please contact our mailing list or join our IRC channel.