Ken, any comment on feasibility of this patch, perhaps in time for this weekend's release? -mt
On 7 June 2011 12:31, Michael Terry <[email protected]> wrote: > I have a potential fix... It's a bit hackish, but seems to work. > Basically, when we resume, we just always redo the last block. There > could be a more elegant patch, where we download the last block and > check its hash, but this was easier. > > Ken, I can do the download-block-check-hash patch if ya like. I'm > also curious if you think there would be any side effects of redoing > the last block, with either version of the patch. > > The simple patch is attached as well as a testing script to reproduce > the bug reliably. > > -mt > > > On 7 June 2011 10:09, Michael Terry <[email protected]> wrote: >> Hello! I was looking at >> https://bugs.launchpad.net/deja-dup/+bug/487720 again, which I'll >> summarize. If something goes wrong when backing up, a partial file >> can get left on the backup target. This partial file confuses >> duplicity and the sha1 sum for the partial file doesn't match what >> duplicity expects for the complete file and the user gets "Invalid >> data - SHA1 hash mismatch". >> >> Now, it was originally thought this only affected ssh. I think more >> accurately, it affects at least the gio and local backends. The >> original report was from Deja Dup using the gio backend. Various >> me-toos on the bug have discussed smb (I know that reporter was using >> gio), ftp, and s3. >> >> For gio, a temporary file will only be used if the target file already >> exists. Otherwise it just writes directly to the target. Local >> (file://) targets always just write directly. >> >> A naive approach would be to add an extra layer to backend.py that >> says if there was an exception during a write, delete any partial >> target file that may have been written. But that wouldn't really >> solve all cases like computer shutting down or a kill signal to >> duplicity. >> >> Would it make sense to augment the resume code to check the sha1sum of >> the most recent chunk and restart that chunk if the sums don't match? >> >> -mt >> > _______________________________________________ Mailing list: https://launchpad.net/~duplicity-team Post to : [email protected] Unsubscribe : https://launchpad.net/~duplicity-team More help : https://help.launchpad.net/ListHelp
