Re: Need help mounting broken btrfs Fedora 19

[Dave Barnum <dave@thebarnums.com>]

Thanks Wang,

This was the result:
root@ubuntu:/downloads/btrfs-progs# ./btrfs chunk-recover /dev/sdc2
no recoverable chunk
Recover the chunk tree successfully.

Still unable to mount.

On Sun, Jul 14, 2013 at 2:03 PM, Wang Shilong <wangshilong1991@gmail.com> wrote:
> Hello,
>
> You call pull from:
>         git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-progs.git
>
> Miao implement chunk tree recover function, you can try it with like.
>         btrfs  chunk-recover /dev
> Maybe this can help you.
>
> Thanks,
> Wang
>> I need some help as may have lost some number of files on a btrfs raid
>> 1 volume. I'm not quite sure what happend which, I know, only adds to
>> the problem.
>>
>> On my computer #1 I had only a month or so ago installed Fedora 19
>> Beta and at the time of install chose BTRFS, raid 1. Recently one of
>> the drives started complaining that it was going to die. WIthout
>> taking it out of the array (perhaps I should have done that) I turned
>> off the system and swapped the drive with another. From then on I lost
>> my ability to boot the system. I could not get anything to work with
>> the new hard drive. Then I put the old hard drive back in so that I
>> could try to boot again. Still nothing. At one point I think I was
>> able to see grub - but at this point, I'm not. I just get boot disk
>> failure.
>>
>> Further more on the failing drive, drive A, I can still see the
>> patitions but I cannot mount it on another system. On drive B (the
>> other half of the mirror) I do not see any partitions. I tried copying
>> the partition structure using sfdisk from A to B but that probably was
>> not smart.
>>
>> I plugged drive A into computer #2 using a live Fedora and Ubuntu CD
>> to try to mount the volume. However in both distributions I am unable
>> to mount the volume. I've tried mounting using -o degraded but I still
>> get the same error. The error I'm seeing when I try to mount the
>> filesystem goes like this:
>>
>> Quote:
>> [10792.307425] device label fedora_ison devid 2 transid 48720 /dev/sdc2
>> [10792.308202] btrfs: allowing degraded mounts
>> [10792.308206] btrfs: disk space caching is enabled
>> [10792.308599] btrfs: failed to read chunk root on sdc2
>> [10792.308799] btrfs warning page private not zero on page 20979712
>> [10792.320146] btrfs: open_ctree failed
>>
>> I believe the superblock may be in tact since when i turn the command
>> ./btrfs-show-super /dev/sdc2 I get:
>>
>> Quote:
>> root@ubuntu:/downloads/btrfs-progs# ./btrfs-show-super /dev/sdc2
>> superblock: bytenr=65536, device=/dev/sdc2
>> ---------------------------------------------------------
>> csum 0xfc19c468 [match]
>> bytenr 65536
>> flags 0x1
>> magic _BHRfS_M [match]
>> fsid cbbf7d4c-f7a0-43ff-aed5-77b347d6ff25
>> label fedora_ison
>> generation 48720
>> root 1105526784
>> sys_array_size 226
>> chunk_root_generation 46504
>> root_level 1
>> chunk_root 20979712
>> chunk_root_level 1
>> log_root 0
>> log_root_transid 0
>> log_root_level 0
>> total_bytes 2988521291776
>> bytes_used 598216536064
>> sectorsize 4096
>> nodesize 4096
>> leafsize 4096
>> stripesize 4096
>> root_dir 6
>> num_devices 2
>> compat_flags 0x0
>> compat_ro_flags 0x0
>> incompat_flags 0x1
>> csum_type 0
>> csum_size 4
>> cache_generation 48720
>> dev_item.uuid 5f61edaa-7f12-4ec5-a024-02f7797e1400
>> dev_item.fsid cbbf7d4c-f7a0-43ff-aed5-77b347d6ff25 [match]
>> dev_item.type 0
>> dev_item.total_bytes 1494260645888
>> dev_item.bytes_used 482110078976
>> dev_item.io_align 4096
>> dev_item.io_width 4096
>> dev_item.sector_size 4096
>> dev_item.devid 2
>> dev_item.dev_group 0
>> dev_item.seek_speed 0
>> dev_item.bandwidth 0
>> dev_item.generation 0
>>
>> Could someone help me troubleshoot why I can't mount my volume? I
>> would REALLY appreciate it! Perhaps there is a way to repair my broken
>> tree structure?
>>
>> Thank You!
>> --
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