rename only repair mode (quickly skip non matching files)

[sjpotter]

I currently ran into a situation where I accidentally renamed 1000 files (about 270GB in total) of files protected by multiple par2 sets (but all mixed together now).

It seems the only way to recover it is to iterate over every par2 file and pass in all the renamed files to the cmdline so it can see what can match.

However, it tries to do this to find blocks in all the files, so it scans them very slowly to do this.

I'm wondering if there would be better to have a "rename only" mode, where we make the assumption that the file really has no errors besides being renamd, so as soon as we see the start of the file doesn't match any of the files we expect, we can ignore it and move on, thereby saving huge amounts of IO.

similarly, once it found all the files complete and just need to rename, it can stop processing the rest of the file list passed in (as its just a rename, not a recovery, so we have all the data we need)

thoughts?

[animetosho]

Sounds like a neat feature, but would you be able to post it to the upstream project? If it gets implemented there, it'll get pulled down here.

[sjpotter]

ok. didn't realize this was mostly focused on the math only, but that makes sense.

[sjpotter]

FYI: made a POC on upstream that works well for my needs - Parchive#185 but unsure how much movement actually happens on that repo.