Fixes#11184Fixes#11237
In prev (broken) fix for https://github.com/scylladb/scylladb/issues/11184 we added the footprint for left-over
files (replay candidates) to disk footprint on commitlog init.
This effectively prevents us from creating segments iff we have tight limits. Since we nowadays do quite a bit of inserts _before_ commitlog replay (system.local, but...) we can end up in a situation where we deadlock start because we cannot get to the actual replay that will eventually free things.
Another, not thought through, consequence is that we add a single footprint to _all_ commitlog shard instances - even though only shard 0 will get to actually replay + delete (i.e. drop footprint).
So shards 1-X would all be either locked out or performance degraded.
Simplest fix is to add the footprint in delete call instead. This will lock out segment creation until delete call is done, but this is fast. Also ensures that only replay shard is involved.
To further emphasize this, don't store segments found on init scan in all shard instances,
instead retrieve (based on low time-pos for current gen) when required. This changes very little, but we at last don't store
pointless string lists in shards 1 to X, and also we can potentially ask for the list twice.
More to the point, goes better hand-in-hand with the semantics of "delete_segments", where any file sent in is
considered candidate for recycling, and included in footprint.
Closes#11251
* github.com:scylladb/scylladb:
commitlog: Make get_segments_to_replay on-demand
commitlog: Revert/modify fac2bc4 - do footprint add in delete
a9573b84c5