Re: external harddisk: bogus corrupt leaf error?

[Martin Steigerwald <martin@lichtvoll.de>]

Qu Wenruo - 21.09.20, 13:14:05 CEST:
> >> For the root cause, it should be some older kernel creating the
> >> wrong
> >> root item size.
> >> I can't find the commit but it should be pretty old, as after v5.4
> >> we
> >> have mandatory write time tree checks, which will reject such write
> >> directly.
> > 
> > So eventually I would have to backup the disk and create FS from
> > scratch to get rid of the error? Or can I, even if its no subvolume
> > involved, find the item affected, copy it somewhere else and then
> > write it to the disk again?
> That's the theory.
> 
> We can easily rebuild that data reloc tree, since it should be empty
> if balance is not running.
> 
> But we don't have it ready at hand in btrfs-progs...
> 
> So you may either want to wait until some quick dirty fixer arrives,
> or can start backup right now.
> All the data/files shouldn't be affected at all.

Hmmm, do you have an idea if and when such a quick dirty fixer would be 
available?

Also, is it still safe to write to the filesystem? I looked at the disk, 
cause I wanted to move some large files over to it to free up some space 
on my laptop's internal SSDs.

If its still safe to write to the filesystem, I may just wait. I will 
refresh the backup of the disk anyway. But if its not safe to write to 
it anymore, I would redo the filesystem from scratch. Would give the 
added benefit of having everything zstd compressed and I could also go 
for XXHASH or what one of the faster of the new checksum algorithms was.

Best,
-- 
Martin