I was reading the other messages in the mailing list, and tried the advice on http://www.mail-archive.com/linux-btrfs@xxxxxxxxxxxxxxx/msg27524.html I checked out the latest code, did a make of the btrfs-tools # sudo btrfs rescue chunk-recover -vy /dev/sda1 All Devices: Device: id = 1, name = /dev/sda1 This ran for some time (half an hour or so) which was reassuring, but then it failed with btrfs: chunk-recover.c:124: process_extent_buffer: Assertion `!(exist->nmirrors >= 2)' failed. :-( Geert On Tue, Oct 22, 2013 at 10:08 AM, Geert Van Damme <geert.vandamme@xxxxxxxxxx> wrote: > Hi, > > I use btrfs for my /home drive. It's a separate drive with just a > single partition. > I upgraded to ubuntu 13.10 (beta) a few weeks ago, without any real > trouble. But I did have too many issues (not with the drive or btrfs, > though) so I decided to do a fresh install. > The new install failed a few times, so I made another startup usb > drive with another program and that one worked fine. > However, my /dev/sda1 was now recognised as an ext4 instea of btrfs. > It also had some files on it (a default ubuntu /home and a > /lost+found) > I can't mount the drive as type=btrfs > > sudo mount -t btrfs /dev/sda1 /mnt/btrfs/ > mount: wrong fs type, bad option, bad superblock on /dev/sda1, > missing codepage or helper program, or other error > In some cases useful info is found in syslog - try > dmesg | tail or so > > > sudo dmesg | grep btrfs > [ 187.604312] btrfs[2771]: segfault at ac ip 000000000042b93b sp > 00007fff918332c8 error 4 in btrfs[400000+4d000] > [ 196.574435] btrfs[2777]: segfault at ac ip 000000000042b93b sp > 00007fff0f04d8a8 error 4 in btrfs[400000+4d000] > [ 241.698698] btrfs[2800]: segfault at ac ip 000000000042b93b sp > 00007fffb1d02b08 error 4 in btrfs[400000+4d000] > > > > Everything I tried crashed, except for 'show' > > > sudo btrfs fi show > failed to open /dev/sr0: No medium found > Label: none uuid: 183af3e0-2572-4497-9705-1d27a6657f7b > Total devices 1 FS bytes used 746.23GB > devid 1 size 2.73TB used 2.73TB path /dev/sda1 > > Btrfs v0.20-rc1 > > > which makes it more or less reassuring that the data is still there, > but I can't seem to find a way to get it :-( > At the moment I restored a backup, so I'm fine more or less, but it > would be nice if I could fix this. > > > sudo btrfs fi df /dev/sda1 > ERROR: couldn't get space info on '/dev/sda1' - Inappropriate ioctl for device > > > sudo btrfsck /dev/sda1 > Check tree block failed, want=21000192, have=0 > Check tree block failed, want=21000192, have=0 > Check tree block failed, want=21000192, have=0 > Check tree block failed, want=21000192, have=0 > Check tree block failed, want=21000192, have=0 > read block failed check_tree_block > Couldn't read chunk root > > > sudo btrfs restore -i -v /dev/sda1 /home/geert/recover > Check tree block failed, want=21000192, have=0 > Check tree block failed, want=21000192, have=0 > Check tree block failed, want=21000192, have=0 > Check tree block failed, want=21000192, have=0 > Check tree block failed, want=21000192, have=0 > read block failed check_tree_block > Couldn't read chunk root > Could not open root, trying backup super > Check tree block failed, want=21000192, have=0 > Check tree block failed, want=21000192, have=0 > Check tree block failed, want=21000192, have=0 > Check tree block failed, want=21000192, have=0 > Check tree block failed, want=21000192, have=0 > read block failed check_tree_block > Couldn't read chunk root > Could not open root, trying backup super > No valid Btrfs found on /dev/sda1 > Could not open root, trying backup super > > > btrfs chunk-recover ran for a few moments, but then failed with > > btrfs: cmds-chunk.c:125: process_extent_buffer: Assertion > `!(exists->nmirrors >=2)´ failed. > > It looks like the chunk-recover command isn't any more available in > the latest btrfs-tools package I installed (from > https://launchpad.net/~samuel-maftoul/+archive/btrfs-tools/+build/4461274). > > It did work with the default btrfs from ubuntu 13.10 though, but > showed the error above > > It looks a lot similar to > http://www.mail-archive.com/linux-btrfs@xxxxxxxxxxxxxxx/msg27390.html > and > http://www.spinics.net/lists/linux-btrfs/msg26274.html > > Is there anything else I could try? -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html