Qu Wenruo kirjoitti 23/06/2022 klo 7.52:

That makes sense, but that also means the extent allocator needs extra
info, not just which space is available.

And there would make ENOSPC handling even more challenging, what if we
have no space left but only partially written stripes?

There are some ideas, like extra layer for RAID56 to do extra mapping
between logical address to physical address, but I'm not yet confident
if we will see new (and even more complex) challenges going that path.

Isn't there already in btrfs system in place for ENOSPC situation? You 
just add some space temporaly? Thats what I remember when I was playing 
around with different situations with btrfs.
For me bigger issue with btrfs raid56 is the fact that scrub is very 
very slow. That should be one of the top priority to solve.

// JiiPee