Re: [PATCH RFC 2/8] fs: add a global device to super block hash table

> 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.