Arch Linux

atk91

Member

Registered: 2021-08-31

Posts: 9

Unmountable btrfs, can't read superblock, but all supers are valid!

Long story short,

# mount -t btrfs /dev/sdb1 /mnt/data 
mount: /mnt/data: can't read superblock on /dev/sdb1.
       dmesg(1) may have more information after failed mount system call.
# btrfs rescue super-recover /dev/sdb1
All supers are valid, no need to recover

That's confusing - mount can't read superblock, btrfs rescue super recover prints they all good.
I cannot mount my filesystem even with ro option.

I can select other superblock from its copy:

# btrfs-select-super -s 1 /dev/sdb1                 
using SB copy 1, bytenr 67108864

However filesystem still won't mount.

dmesg shows the following:

[ 4321.533552] BTRFS info (device sdb1): first mount of filesystem 0f1b4ec0-ae7f-4088-a764-04aae5400bb8
[ 4321.533569] BTRFS info (device sdb1): using crc32c (crc32c-intel) checksum algorithm
[ 4321.533574] BTRFS info (device sdb1): disk space caching is enabled
[ 4321.539647] BTRFS info (device sdb1): bdev /dev/sdb1 errs: wr 0, rd 0, flush 0, corrupt 569, gen 0
[ 4321.544333] BTRFS info (device sdb1): checking UUID tree
[ 4321.544961] BTRFS error (device sdb1): parent transid verify failed on logical 72957952 mirror 1 wanted 123544 found 123535
[ 4321.545124] BTRFS error (device sdb1): parent transid verify failed on logical 72957952 mirror 2 wanted 123544 found 123535
[ 4321.545148] BTRFS: error (device sdb1) in btrfs_fill_super:955: errno=-5 IO failure
[ 4321.545334] BTRFS error (device sdb1 state E): commit super ret -30

What's happening and may I restore the filesystem or my data is gone?

Head_on_a_Stick

Member

From: The Wirral

Registered: 2014-02-20

Posts: 9,003

Website

Re: Unmountable btrfs, can't read superblock, but all supers are valid!

Try https://bbs.archlinux.org/viewtopic.php?id=233724.

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Jin, Jîyan, Azadî

atk91

Member

Registered: 2021-08-31

Posts: 9

Re: Unmountable btrfs, can't read superblock, but all supers are valid!

I tried `btrfsck --init-extent-tree` - it finished after few days, btrfs mounts now but all my data is gone

Head_on_a_Stick

Member

From: The Wirral

Registered: 2014-02-20

Posts: 9,003

Website

Re: Unmountable btrfs, can't read superblock, but all supers are valid!

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Jin, Jîyan, Azadî