Researching more, I see POSIX has NO way to disable mtime updating while calling write()'s, so there is no way to atomically leave a partial file with an mtime=0 mark while using --inplace.
"rsync --update --partial" (no --inplace) can do it because it transfers first to a temporal file, then updates his mtime (to 0 if unsuccessful, or to the original file mtime if transfer completed), and then rename()'s the file. So now I think this can't be solved, but a warning should be placed in the rsync manpage about this "-u --partial" unexpected behavior. Take this as a documentation bug. -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to rsync in Ubuntu. https://bugs.launchpad.net/bugs/1659950 Title: rsync -u --inplace --partial -a can't resume transfer Status in rsync package in Ubuntu: New Bug description: Suppose you have a file in hostA: hostA$ ls -l /tmp/files -rw-rw-r-- 2 root root 563016 Jan 10 15:01 test.txt You download it from the hostB using: hostB$ rsync -u --inplace --partial -a hostA::files/* . If the transfer is aborted, hostB will get only a partial file: hostB$ ls -l /tmp/files -rw-rw-r-- 2 root root 2024 Jan 11 18:00 test.txt BUT the ctime/mtime of hostB/test.txt now is NEWER than hostA/test.txt(and mtime == ctime). So, if you run the same rsync -u command again: hostB$ rsync -u --inplace --partial -a hostA::files/* . Rsync will SKIP THE FILE, because hostB/test.txt is "newer" than hostA/test.txt. So you CAN'T resume using rsync -u command, and you will think there are no differences. To avoid this bug, rsync must create the file with ctime=mtime=0. And if the file already exists before transfer, rsync -u must not change his current ctime/mtime. Ctime/mtime must be updated ONLY after the transfer was successfully completed. Note this is really need because there are scenarios where checksum comparison can't be used, only comparison by time. For example, to avoid deleting changes made in hostB to test.txt. Also I need to use --inplace. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/rsync/+bug/1659950/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
