Correct way to clear a free space cache file invalid error

[Martin Steigerwald <martin@lichtvoll.de>]

Sorry for incomplete subject, reposting.

Hi!

Kernel 6.1, btrfs-progs 6.1.2. Filesystem on NVME SSD, via LVM and dm-
crypt.

I would like

[   18.657903] BTRFS info (device dm-1): the free space cache file 
(23912775680) is invalid, skip it
[   18.697033] BTRFS info (device dm-1): the free space cache file 
(25254952960) is invalid, skip it

to be gone.

So I tried

mount -o remount,clear_cache,space_cache=v1 /

as well as

mount -o remount,clear_cache /
mount -o remount,space_cache=v1 /

to no avail.

Before that I had space cache v2 on the filesystem as with most of my 
other BTRFS filesystems. But since it really should not be necessary for 
a 50 GiB filesystem for the Linux system (not user data), I thought I 
play it safe this time. At least from what I learned from btrfs manpage.

In a page on BTRFS wiki it is stated that one should run "btrfs check" 
on the filesystem.

So what is the correct way to clear that error?

I did not perceive any malfunctioning due to the error in dmesg. The 
filesystem scrubs without errors.

Best,
-- 
Martin