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 >>>>
Attachment:
super_dump.sdb
Description: Binary data
