When an upload failed part way through with a retryable error (eg a
502 from the block storage servers) the pacer retried the whole upload
call with the same input stream. The stream had already been partially
consumed, so the retry re-created the upload draft and committed just
the remainder of the stream as a complete file, silently truncating
it. With restic over serve restic this corrupted the repository as the
truncated pack was reported as successfully uploaded.
This fixes it by using CallNoRetry for the upload, as the other
backends do, so retryable errors are returned wrapped in a RetryError
for the caller to retry the upload with a fresh stream.
Nick Craig-Wood
a06df7a2de