> No, we don't need a secondary device number to sb mapping. On the other > hand we do need the deviceloss, freeze etc upcalls to work for owners > that are not file systems like mdraid or dm, even if they have been > slow to pick this. The whole idea of the holder ops is to abstract > away from who holds it instead of adding back the broken hard coding > of the superblock. Otherwise you're just badly reinventing get_super.
No, the expanded version works for all device numbers. There's also no-hardcoding. And non-fs users may do whatever they want with their holder ops ofc. erofs always had the non 1:1 relationship between devices and filesystems and for that case it seems sane. I'm happy to let the series sit for a bit to gather input and do the security mediation patches first. The series are complementary.
