Am 30.01.2017 um 22:20 schrieb Chris Murphy: > On Mon, Jan 30, 2017 at 2:07 PM, Michael Born <michael.b...@aei.mpg.de> wrote: >> The files I'm interested in (fstab, NetworkManager.conf, ...) didn't >> change for months. Why would they change in the moment I copy their >> blocks with dd? > > They didn't change. The file system changed. While dd is reading, it > might be minutes between capturing different parts of the file system, > and each superblock is in different locations on the disk, > guaranteeing that if the dd takes more than 30 seconds, your dd image > has different generation super blocks. Btrfs notices this at mount > time and will refuse to mount because the file system is inconsistent. > > It is certainly possible to fix this, but it's likely to be really, > really tedious. The existing tools don't take this use case into > account. > > Maybe btfs-find-root can come up with some suggestions and you can use > btrfs restore -t with the bytenr from find root, to see if you can get > this old data, ignoring the changes that don't affect the old data. > > What you do with this is btrfs-find-root and see what it comes up > with. And work with the most recent (highest) generation going > backward, plugging in the bytenr into btrfs restore with -t option. > You'll also want to use the dry run to see if you're getting what you > want. It's best to use the exact path if you know it, this takes much > less time for it to search all files in a given tree. If you don't > know the exact path, but you know part of a file name, then you'll > need to use the regex option; or just let it dump everything it can > from the image and go dumpster diving...
I really want to try the "btrfs-find-root / btrfs restore -t" method. But, btrfs-find-root gives me just the 3 lines output and then nothing for 16 hours. I think, I saw a similar report that the tool just doesn't report back in the mailing list archive (btrfs-find-root duration? Markus Binsteiner Sat, 10 Dec 2016 16:12:25 -0800) ./btrfs-find-root /dev/loop0 Couldn't read tree root Superblock thinks the generation is 550114 Superblock thinks the level is 1 Hans, also thank you for the explanation even though I'm not sure, I understand. I would be happy with older parts of the tree which then have lower numbers than the 550112. Michael -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
