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* Can't mount RAID-0 btrfs volume
@ 2023-07-01 14:59 yeslow
  2023-07-01 18:13 ` Roman Mamedov
  0 siblings, 1 reply; 3+ messages in thread
From: yeslow @ 2023-07-01 14:59 UTC (permalink / raw)
  To: linux-btrfs@vger.kernel.org

Hello,

I have a dual boot system with Windows 10 Pro and Linux Kubuntu 22.04.

I have created a btrfs raid-0 volume in my Linux system with 2 SSD drives to store not very important files, where the speed is most important. I then use winbtrfs in the Windows 10 system to be able to access the btrfs volume, when using Windows 10.

Everything worked fine for several months until recently. I deleted some files on the btrfs volume in Windows 10, which always worked fine, but this time I noticed that after the file deletion the volume in Linux was not showing the expected free space. When trying to have this fixed, I decided to give it a try by using the command: btrfs check --clear-space-cache v2

Wrong decision, because after that I got a warning message (don't remember which), and the next time I booted my computer the volume was not possible to mount.

Now, when I run the command: sudo btrfs check --readonly /dev/sda1

I get the following:
Opening filesystem to check...
checksum verify failed on 18266193920 wanted 0x34bed84997ecd963 found 0x9ee6d0c7b17903ec
checksum verify failed on 18266193920 wanted 0x0000000000000000 found 0x3e76427c81028f58
checksum verify failed on 18266193920 wanted 0x34bed84997ecd963 found 0x9ee6d0c7b17903ec
bad tree block 18266193920, bytenr mismatch, want=18266193920, have=6237172951202995731
ERROR: cannot read chunk root
ERROR: cannot open file system

I have tried googling these error messages and found this mailing list. I have tried some suggestions found here:

1)
sudo mount -t btrfs -o rescue=all,ro /dev/sda1 /z1
result:
mount: /z1: can't read superblock on /dev/sda1

dmesg:
[23664.424317] BTRFS info (device sda1): using xxhash64 (xxhash64-generic) checksum algorithm
[23664.424349] BTRFS info (device sda1): enabling all of the rescue options
[23664.424355] BTRFS info (device sda1): ignoring data csums
[23664.424360] BTRFS info (device sda1): ignoring bad roots
[23664.424364] BTRFS info (device sda1): disabling log replay at mount time
[23664.424370] BTRFS info (device sda1): disk space caching is enabled
[23664.425981] BTRFS error (device sda1): bad tree block start, mirror 1 want 18266193920 have 6237172951202995731
[23664.426101] BTRFS error (device sda1): bad tree block start, mirror 2 want 18266193920 have 0
[23664.426127] BTRFS error (device sda1): failed to read chunk root
[23664.427009] BTRFS error (device sda1): open_ctree failed

2) sudo btrfs rescue super-recover -v /dev/sda1
result:
All Devices:
        Device: id = 2, name = /dev/sde1
        Device: id = 1, name = /dev/sda1

Before Recovering:
        [All good supers]:
                device name = /dev/sde1
                superblock bytenr = 65536

                device name = /dev/sde1
                superblock bytenr = 67108864

                device name = /dev/sde1
                superblock bytenr = 274877906944

                device name = /dev/sda1
                superblock bytenr = 65536

                device name = /dev/sda1
                superblock bytenr = 67108864

                device name = /dev/sda1
                superblock bytenr = 274877906944

        [All bad supers]:

All supers are valid, no need to recover

---

This volume has some files that I would like to recover. Is there any possibility of fixing this, just to allow me to copy the files that I need? Or is the volume completely broken and all data lost, and then I should simply create a new volume again?

My apologies if this is not the right place for asking this, but the only place where google search showed meaningful answers was here.

My thanks in anticipation.


^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2023-07-01 19:52 UTC | newest]

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2023-07-01 14:59 Can't mount RAID-0 btrfs volume yeslow
2023-07-01 18:13 ` Roman Mamedov
2023-07-01 19:52   ` yeslow

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