- track block versions correctly - per inode block (128kb) instead of tree block (4kb)
- prevent multiple parallel CAS writes of the same inode block
- add logging for EILSEQ which means invalid data in the tree
- fix get_block updated flag which was true for blocks already in cache and was leading to infinite loops on "unrelated block" errors
- apply changes to blocks in cache only after successful writes (using "virtual changes")
- do not replace cached block with an older version from disk
- recheck "unrelated blocks" (read/update collisions) until data stops changing
- track tree path correctly - do not treat split block as parent of its right half
- correctly move blocks when finding new empty place on disk
- restart updates from the beginning when one of blocks is changed by a parallel update
- fix delete using SET opcode and setting key to the empty value instead
- prevent changing the same key more than 1 time in parallel
- fix listing verification
- resume continue_updates in update_find (required because it uses continue_update itself)
- add allow_old_cached parameter to get()
Fixes a possible use-after-free in case of continue_ops() calling try_send(),
then connect_peer() -> set_timer() -> trigger_nearest() -> handle_op_part() -> continue_ops() again
OSDs often change their /pg/history keys during rebalance, so monitor receives additional
transaction failures from etcd if it re-runs lpsolve which sometimes may even lead to monitor
being unable to apply PG changes at all until rebalance completes
Also add protection from etcd watcher messages being split into multiple websocket
messages - I'm not sure if etcd actually does that, but it's better to have extra
protection anyway.
Also check that all etcd watchers are started in the keepalive routine, otherwise
it sometimes tries to revive etcd watchers starting with revision=1 which obviously
always fails because this revision is nearly always compacted.
All these changes should fix an old rarely reproduced bug where SOMETIMES OSDs
didn't react to PG config changes which was leading to offline pools on node reboot.
It happened on the full reload of state from etcd.
Vitaliy Filippov