Comment 5 for bug 580855

This seems to be caused by a loop:

  1. File gets created.
  2. File gets written.
  3. Metadata gets created.
  4. File gets renamed.
  5. Hash queue fails (file no longer there)

Step 5 causes the file to be re-sent to the hash queue, which
keeps failing as the file is gone. This create a file and then rename
pattern is pretty typical of apps that save documents. I got it to happen
using rsync, which also uses temporary files which are then renamed.

One way to fix it is to check that the file is still accessible before re-attmempting
the hash. I have small patch here, sans tests, which at least fixes it for me.

https://code.launchpad.net/~dave-krondo/ubuntuone-client/lucid-updates-580855