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
- Write operations could be 'stabilized' and previous versions could be
purged from OSDs before the removal of version_override and following
reads could potentially hit different version in EC pools
- Object was marked clean after completing the delete during recovery, so
reads could in theory hit a deleted version and return nothing
Previously OSDs could commit deletes before writes during recovery or rebalance
in the "lazy fsync" (immediate_commit=off) mode which could result in lost objects
Vitaliy Filippov