Transmission loses track of downloaded content on external drives when they're unmounted

[Mike Birch]

Binary package hint: transmission

Transmission 1.93 (10621)
Karmic, Lucent and possibly Maverick. Currently using netbook edition but this bug seems to be by design.

Reproduction:
Download complete torrents to a removable USB drive.
Close Transmission.
Unmount drive (or wait for the system to forget about it! Grr!)
Start Transmission.
* All of the torrents are unavailable as expected.
End Transmission, re-mount drive and start transmission.
The torrents are all paused _with zero bytes downloaded_.
Starting a torrent results in it transmission blindly attempting to re-download data over the top of what's already there.
Only by explicity verifying local data (a big task with >100 torrents) does it accept that they are already downloaded, not to mention those you manually paused which are now indistinguishable from any other.

Expected:
Missing files should not zero totals and pause the torrent. For the current session, they should be marked invalid but their general status should be left untouched. If the data file reappears on subsequent sessions, it should continue where it left off. If it insists on verifying the data, it should do so quietly and not explicitly require it. Re-downloading over the top is right out!

[Charles Kerr (charlesk)]

This is in progress for 2.20

[Mike Birch (mike-immortalsofar)]

Great! Can I add a little addition, still on the theme of dynamic file systems?

If, during a download, the destination device is removed or dropped then the download continues unaware. It can claim to have downloaded the entire file and it is only when the device is remounted and local data verified that the problems come to light.

Reproduction steps:
Start download to a removable device.
Remove device.
(Download continues without successfully saving to the device).
Reconnect device.
Verify local data.
(The percentage downloaded gets reduced until the actual saved data is reached - this part is correct).

Expected:
Check the return value when writing data. When a write (perhaps with retries) fails, the destination file should be marked temporarily unavailable or, at worst, the torrent paused.

[phonixor (phonixor)]

Confirmed

Expected:
On launching transmission, check for any devices that should have torrents on them (but forgotten or whatever the technical term is..) and enable them...
maybe a quick scan to see if the files are there, and then just assume that the last known status of the client was the right one... so continue the download, instead of a full verify local data...
(i think its pretty uncommon to have multiple clients working on the same torrent, so this behavior would be preferred)

same behavior if the device is unplugged and reinserted during a torrent download:
(quick rescan and asume its ok...)

[phonixor (phonixor)]

Damnit Ubuntu needs to update its repositories!!!
2.13 v 2.22
THIS SUCKS MONKEY BALLS!!!
more then a month behind for there default apps is unacceptable...
(its not a library, so no need to wait 6 months... ... though they waited longer :@)

[Charles Kerr (charlesk)]

Thank you for your bug report. To maintain a respectful atmosphere, please follow the code of conduct - http://www.ubuntu.com/community/conduct/ . Bug reports are handled by humans, the majority of whom are volunteers, so please bear this in mind.

[Sergey Fukanchik (fuxx)]

Can this bug be fixed in 10.04 which is Long Term Support?

[Krzysztof Klimonda (kklimonda)]

This bug has been fixed around 2.20 which means it's fixed in 11.10 - quick glance at the upstream bug report shows that it's not suitable for backporting it to the transmission release from 10.04, especially this close to the 12.04 release.

I'm closing the bug as "Fix Released" as it's fixed in the stable Ubuntu release.