Sync before listing was added to wait for all PG writes possibly left in queue
from the previous master to finish before listing it
But in fact it may block the cluster when EC is used and some unstable writes
are left in the queue - they block journal flushing, rollback/stabilize is
required to unblock them, but rollback/stabilize may only happen after PG is
peered. But peering needs listings, listings are requested only after sync, and
sync itself waits for currently blocked writes waiting in the queue
Build problems fixed:
- void* pointer arithmetic which is a GNU extension (works as byte*)
- "variable size object may not be initialized" which is OK under GCC
- nullptr_t related error in json11 (it lacks 'operator <' in clang)
Warnings fixed:
- empty nested struct initializer { 0 } replaced by {}
- removed several unused lambda captures
Slightly reduces WA. For example, in 4K T1Q128 replicated randwrite tests
WA is reduced from ~3.6 to ~3.1, in T1Q64 from ~3.8 to ~3.4.
Only effective without no_same_sector_overwrites.
Make syncs wait for all previous writes because it's the only way
to make sure that OSDs do not receive incomplete writes in LIST results
during peering when some writes are still in progress.
Also simplify blockstore submission queue logic.
Vitaliy Filippov