I'd like to pass on observations from my collegue Neil Brown: in src/copy.c, copy_reg() is passed "bool *new_dst".
This is 'false' if the file already exists, in which case it attempts to open the file with O_WRONLY | O_TRUNC | O_BINARY. If it is 'true', only then does it use O_CREAT (and others). Somewhere up the call chain - I'm not sure where - new_dst is set if 'stat' on the file succeeds. The above mentioned code assumes that the file still exists. This is racy - particularly for NFS where deletions from other clients can take a while to appear. Philipp
