If we get errors/exceptions in delete_segments we can (and probably will) loose track of disk footprint counters. This can in turn, if using hard limits, cause us to block indefinitely on segment allocation since we might think we have larger footprint than we actually do.
Of course, if we actually fail deleting a segment, it is 100% true that we still technically hold this disk footprint (now unreachable), but for cases where for example outside forces (or wacky tests) delete a file behind our backs, this might not be true. One could also argue that our footprint is the segments and file names we keep track of, and the rest is exterior sludge.
In any case, if we have any exceptions in delete_segments, we should recalculate disk footprint based on current state, and restart all new_segment paths etc.
Fixes#9348
(Note: this is based on previous PR #9344 - so shows these commits as well. Actual changes are only the latter two).
Closes#9349
* github.com:scylladb/scylla:
commitlog: Recalculate footprint on delete_segment exceptions
commitlog_test: Add test for exception in alloc w. deleted underlying file
commitlog: Ensure failed-to-create-segment is re-deleted
commitlog::allocate_segment_ex: Don't re-throw out of function
e2c27ee743