largefiles: respect store.createmode and avoid extra file copy...
largefiles: respect store.createmode and avoid extra file copy
Before, a tempfile was used to create a temp file was created with 600
permissions and the uploaded data was written into it. This file was
then *copied* to .hg/largefiles/<hash>.
We now simply use atomictempfile to write the data to a temp file with
the right permissions and then rename that into place.