The patch from commit e5731f4 ("backport fix for managing block flush
queue list") caused some fallout when used with LVM on root, as that
uses some rather odd (but previously working fine) PREFLUSH
| POSTFLUSH format that was now causing the list to be used without
being initialized, resulting in freezes.
Link: https://lore.kernel.org/all/20240608143115.972486-1-chengming.zhou@linux.dev/
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>