Flush was the only path stamping the watermark, so a truncate or
setattr through saveEntry, a server-side CopyFileRange, or a remote
cache download whose response carried no metadata event could still be
rolled back by an older queued subscription event in a read-through
directory. saveEntry now stamps any open handle for the saved path, and
every site tolerates a response without an event: the metadata cache
tracks the newest filer log timestamp seen in any applied event, and
that position, captured before the RPC, is a safe lower bound for the
state the filer served — anything it returns is at least as new as
every event already delivered.
Chris Lu
36b25fca76