Re: bad tree block start, want 705757184 have 82362368

[Nikolay Borisov <nborisov@suse.com>]

On 16.11.18 г. 18:17 ч., Stephan Olbrich wrote:
> Hi,
> 
> a few days ago my root file system (simple btrfs on a SSD, no RAID or anything) suddenly became read only. 
> Looking at dmsg, I found this:
> 
> [   19.285020] BTRFS error (device sda2): bad tree block start, want 705757184 have 82362368
> [   19.285042] BTRFS: error (device sda2) in __btrfs_free_extent:6804: errno=-5 IO failure
> [   19.285048] BTRFS info (device sda2): forced readonly
> [   19.285051] BTRFS: error (device sda2) in btrfs_run_delayed_refs:2934: errno=-5 IO failure
> [   19.287213] BTRFS error (device sda2): pending csums is 41889792
> 
> Late on I got the same errors for my /home partition (on the same drive) as well.
> I have snapshots of all partitions on another drive made by btrbk. To get a working system, I made new (rw) snapshots
> of the most recent backup and setup grub and fstab, so my system would boot from the other drive.
> Unfortunately now I got the "bad tree block start" error again at least once in dmesg but I didn't save it and it's not in syslog :-(
> What I remember is, that it was followed by other btrfs error messages saying something about correcting something.
> And the filesystem was still read/write this time.
> At the moment I can't reproduce it.
> 
> Is there any way to find out, which files are affected by the errors above? I don't really trust the data on the drive I'm using at the
> moment, as it has shown errors as well, but I have a less current backup on yet another drive but at it is a few weeks old, I don't
> want to use it to setup the system on the SSD again, but just copy the relevant files if possible.
> Or is it possible to repair the original file system?
> 
> Some information about my system:
> Kubuntu 18.04
> Kernel 4.19.1 when the problem occured, now 4.19.2
> btrfs-tools 4.15.1

What is the SMART status of your SSD, how old is the ssd. This really
sounds like the drive going to lalal land.

> 
> Regards,
> Stephan
> 
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