Each inode has: image name, parent inode number & pool, size and readonly flag
Snapshots are created by switching image name to a different inode number
while using the older inode as parent.
Another bunch of fixes, including important ones. Now OSDs are stable in SSD+HDD
configurations and everything is mostly ready for the merge of master branch.
Features:
- Add min_flusher_count configuration (good for HDDs)
- Shuffle PGs for better data device utilisation
- Make OSDs benefit from the immediate_commit=small setting if it's applicable
Bug fixes:
- Rework client code to fix write ordering during operation replay
- Rework error handling code so OSDs don't crash in reaction to a crash of their peer OSDs
- Fix several block layer problems related to the journal, some of which
were leading to double allocations of the same block during journal replay
- Fix monitors crashing during the removal of OSD keys from etcd
- Fix data fsyncs being incorrectly disabled when only disable_journal_fsync was set
- Always zero out unused part of request/reply headers
- Fix some theoretically possible read/write ordering issues
- Don't try to "recover" misplaced objects if it would make them degraded
- Fix heartbeats sometimes preventing OSD to establish connections
The bug reproduced if fio was temporarily stopped with SIGSTOP
during write test and then resumed after 10 seconds. In this case
"pings" were failed for all clients and fio process crashed with
'use-after-free' in keepalive_timer. It happened because it called
stop_client while having a live iterator to the map.
