[6.12] Windows 11 guest causes heavy io and eventually dies when VM is hosted on bcachefs filesystem

[NikolayKuzmin]

Stuck on 6.10 kernel due to unable to work with virtual machine on both 6.11 and 6.12. Here is 6.12 issue:

VM startup takes very long time hdds works like crazy guest startup takes several minutes. Afterward VM session can live for some time, but eventually it will crash. Kernel log contains multiple "journal stuck" messages.
Here is kernel log (without VM crashing, only time needed to load guest's desktop):
kerneltrace-612.log
My bcachefs setup contains 2 nvme ssds (ssd.ssd# naming), 2 cmr hdds (hdd.cmr.cmr#) and 1 smr hdd (hdd.smr.smr#). The only anomaly is SMR drive formatted with 16mb bucket size. But due to targets vm image data shouldn't go to smr.
`

file: win11.raw

bcachefs.background_target="hdd.cmr"
bcachefs.foreground_target="ssd"
bcachefs_effective.background_target="hdd.cmr"
bcachefs_effective.data_replicas="2"
bcachefs_effective.foreground_target="ssd"
`
bcachefs-super.txt