Thanks for your return, but i think the writing of this type of programs is far away for me. Haven't really coded since the amiga 68k assembly time, so... :/
I have appreciated your efforts to trying to help me, but i can't handle this type of solution. I will let this raid RIP until i will find a solution, maybe with futur evolutions of Btrfs-Tools. I wish you a nice day, Thierry Le jeu. 1 avr. 2021 à 11:04, Lukas Straub <lukasstra...@web.de> a écrit : > > On Wed, 31 Mar 2021 23:44:28 +0200 > Thierry Testeur <thierry.test...@gmail.com> wrote: > > > Yep, compression enabled (original fstab before having tried restore > > options): compress=lzo > > Okay, that explains why photorec couldn't recover a lot. If you want to > get your hands dirty, I guess you could write a program that does the > following: > For every 4k block/address on the filesystem, attempt to decompress it > using the btrfs lzo implementation (see fs/btrfs/lzo.c and > lib/lzo/lzo1x_decompress_safe.c in the kernel). > Do some sanity checks: > > Like, check that the length of the compressed data is reasonable. The > decompressed size of an compressed extend can be a maximum of 128k, so > considering the case that data which doesn't compress well may take up > more space in compressed from, the maximum length of the compressed > data should be a bit larger than 128k. I'd say like 256k. > > Also check that the length of the segments is reasonable, etc. > > If all sanity checks passed and decompression worked, look at the > decompressed size: > > If it is exactly 128k, it is likely part of a bigger file. Append all > such data to a output file. > > If it is below 128k, chances are pretty good you just recovered a small > file, save it directly somewhere. You can use the file(1) utility later > to figure out the file-format. > Or it could be the last part of a large file, so always append it to > the output file as well and fill up with zeroes so the end is aligned > to 4k. > > Finally, you can run photorec on the output file that you appended > everything to, to rescue files that are larger than 128k. > > I wish you luck. > > Regards, > Lukas Straub > > > Best regards, > > Thierry > > > > Le mer. 31 mars 2021 à 14:23, Lukas Straub <lukasstra...@web.de> a > > écrit : > > > > > > On Wed, 31 Mar 2021 02:17:48 +0200 > > > Thierry Testeur <thierry.test...@gmail.com> wrote: > > > > > > > Hello, > > > > > > > > if anyone can help me with the problem above? > > > > Have tried a Photorec (even if i know the chance are really > > > > poor), and have got some non-sens files, lkie pdf of 2Gb, .... > > > > most of them are unusable, except smal size file, like jpg pic... > > > > > > > > thanks for any help. > > > > Thierry > > > > > > Weird, I would have expected photorec to recover more. Did you have > > > compression enabled? > > > > > > Regards, > > > Lukas Straub > > > > > > -- > > > > > > > -- >
