Follow-ups to reading a pending remote rename copy from its source key:
- Only the filer sets the marker. The HTTP upload and tagging handlers
store Seaweed-* request headers as extended attributes, so they skip
this one, and a marker that leads out of the entry's own mount is
ignored, so it cannot point reads at another remote.
- A pending entry renamed again copies from the marker's source, not
from its own key, which still holds the old target's bytes. A further
deferred rename keeps naming the original source; an immediate copy
clears the marker.
- When remote.sync finds the destination already holding the content,
it stamps the entry (clearing the marker) before deleting the source,
and deletes the source only once the entry no longer reads it.
- A read that resolved the source just before the copy finished and
the source went away retries with the entry as it is now.
Alex Russell
4e63394302