On 2018年04月08日 10:55, Ben Parsons wrote: > just to confirm: > > I run the following dd command to fix the superblocks: > dd if=super_dump.sdb of=/dev/sdb bs=1 count=4096 skip=64k > dd if=super_dump.sdc1 of=/dev/sdc1 bs=1 count=4096 skip=64k Nope. it's seek=64K Thanks, Qu > > Thanks, > Ben > > On 8 April 2018 at 12:27, Qu Wenruo <quwenruo.btrfs@xxxxxxx> wrote: >> Here you go, all patched super block attached. >> >> Thanks, >> Qu >> >> On 2018年04月08日 10:14, Ben Parsons wrote: >>> Super block of sdb as requested >>> >>> Thanks, >>> Ben >>> >>> On 8 April 2018 at 11:53, Qu Wenruo <quwenruo.btrfs@xxxxxxx> wrote: >>>> >>>> >>>> On 2018年04月08日 08:57, Ben Parsons wrote: >>>>> See attached for requested output. >>>>> >>>>> Do I still need to recover the super block of sdb? >>>> >>>> Yep. Please also attach the binary dump of superblock of sdb. >>>> >>>>> >>>>> Could you please point me the right direction for doing the inplace recovery? >>>> >>>> I'll provide the patched superblock for both disks (sdb and sdc1) >>>> >>>> And with them written back to disk, just run "btrfs check" first, if >>>> nothing wrong, mount it RW and run scrub. >>>> >>>> Pretty straightforward. >>>> >>>> Thanks, >>>> Qu >>>>> >>>>> I have not rebooterd or tried to recover / mount the disc btw. >>>>> >>>>> Thanks, >>>>> Ben >>>>> >>>>> On 8 April 2018 at 10:02, Qu Wenruo <quwenruo.btrfs@xxxxxxx> wrote: >>>>>> >>>>>> >>>>>> On 2018年04月08日 07:29, Ben Parsons wrote: >>>>>>> On 7 April 2018 at 22:09, Qu Wenruo <quwenruo.btrfs@xxxxxxx> wrote: >>>>>>>> >>>>>>>> >>>>>>>> On 2018年04月07日 10:31, Ben Parsons wrote: >>>>>>>> [snip] >>>>>>>>>> Pretty common hard power reset. >>>>>>>>>> >>>>>>>>>>> looking at journalctl, there is a large stacktrace from kernel: amdgpu >>>>>>>>>>> (see attached). >>>>>>>>>>> then when I booted back up the pool (2 disks, 1TB + 2TB) wouldn't mount. >>>>>>>>>> >>>>>>>>>> I'd say such corruption is pretty serious. >>>>>>>>>> >>>>>>>>>> And what's the profile of the btrfs? If metadata is raid1, we could at >>>>>>>>>> least try to recovery the superblock from the remaining disk. >>>>>>>>> >>>>>>>>> I am not sure what the metadata was but the two disks had no parity >>>>>>>>> and just appeared as a single disk with total space of the two disks >>>>>>>> >>>>>>>> Strangely, for the 2nd disk, it's sdc1, which means it has partition table. >>>>>>>> While for the 1st disk, it's sda, without partition table at all. >>>>>>>> Is there any possibility that you just took run partition? >>>>>>>> (Or did some program uses it incorrectly?) >>>>>>>> >>>>>>> >>>>>>> I dont quite understand what you are asking. >>>>>>> I was always under the impression I could run mount on either >>>>>>> partition and it would mount the pool >>>>>>> >>>>>>>>> >>>>>>>>> how would i got about recovering the 2nd disk? attached is >>>>>>>> >>>>>>>> The 2nd disk looks good, however it's csum_type is wrong. >>>>>>>> 41700 looks like garbage. >>>>>>>> >>>>>>>> Despite that, incompact_flags also has garbage. >>>>>>>> >>>>>>>> The good news is, the system (and metadata) profile is RAID1, so it's >>>>>>>> highly possible for us to salvage (to be more accurate, rebuild) the >>>>>>>> superblock for the 1st device. >>>>>>>> >>>>>>>> Please dump the superblock of the 2nd device (sdc1) by the following >>>>>>>> command: >>>>>>>> >>>>>>>> # dd if=/dev/sdc1 of=super_dump.sdc1 bs=1 count=4096 skip=64k >>>>>>>> >>>>>>> >>>>>>> See attached. >>>>>>> >>>>>>>> >>>>>>>> Unfortunately, btrfs-sb-mod tool added recently doesn't have all needed >>>>>>>> fields, so I'm afraid I need to manually modify it. >>>>>>>> >>>>>>>> And just in case, please paste the following output to help us verify if >>>>>>>> it's really sda without offset: >>>>>>>> >>>>>>>> # lsblk /dev/sda >>>>>>>> # grep -obUaP "\x5F\x42\x48\x52\x66\x53\x5F\x4D" >>>>>>>> >>>>>>> >>>>>>> dd if=/dev/sdb of=toGrep.sdb bs=1 count=128M status=progress >>>>>>> cat toGrep.sdb | grep -obUaP "\x5F\x42\x48\x52\x66\x53\x5F\x4D" >>>>>>> >>>>>>> 65600:_BHRfS_M >>>>>>> 67108928:_BHRfS_M >>>>>> >>>>>> Well, the magic number is completely correct, and at correct location. >>>>>> >>>>>> Would you please run "btrfs inspect dump-super -fFa /dev/sdb" again? >>>>>> This time it should provide good data. >>>>>> >>>>>>> >>>>>>>> >>>>>>>> Above grep could be very slow since it will try to iterate the whole >>>>>>>> disk. It's recommended to dump the first 128M of the disk and then grep >>>>>>>> on that 128M image. >>>>>>>> >>>>>>>> >>>>>>>> BTW, with superblock of sdc1 patched, you should be able to mount the fs >>>>>>>> with -o ro,degraded, and salvage some data. >>>>>>>> >>>>>>>> Thanks, >>>>>>>> Qu >>>>>>> >>>>>>> Thank you so much! >>>>>>> >>>>>>> I am better off copying the data to another disk and then rebuilding the pool? >>>>>>> or can I just run a scrub after the super block is fixed? >>>>>> >>>>>> According to your latest grep output, strangely the 1st device is not >>>>>> that corrupted as before. >>>>>> >>>>>> So I think in-place recover should save you a lot of time. >>>>>> >>>>>> Thanks, >>>>>> Qu >>>>>> >>>>>>> >>>>>>> For reference here is lsblk: >>>>>>> >>>>>>> sda 8:0 0 465.8G 0 disk >>>>>>> ├─sda1 8:1 0 512M 0 part /boot >>>>>>> ├─sda2 8:2 0 455.3G 0 part / >>>>>>> └─sda3 8:3 0 10G 0 part [SWAP] >>>>>>> >>>>>>> sdb 8:16 0 931.5G 0 disk >>>>>>> -- first disk >>>>>>> >>>>>>> sdc 8:32 0 1.8T 0 disk >>>>>>> └─sdc1 8:33 0 1.8T 0 part >>>>>>> -- 2nd disk >>>>>>> > -- > 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 > -- 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
