Re: [man-pages RFC PATCH v4] statx, inode: document the new STATX_INO_VERSION field

Al Viro
2022-09-10T19:48:29Z

On Thu, Sep 08, 2022 at 10:40:43AM +1000, NeilBrown wrote:

> We do hold i_rwsem today. I'm working on changing that. Preserving
> atomic directory changeinfo will be a challenge. The only mechanism I
> can think if is to pass a "u64*" to all the directory modification ops,
> and they fill in the version number at the point where it is incremented
> (inode_maybe_inc_iversion_return()). The (nfsd) caller assumes that
> "before" was one less than "after". If you don't want to internally
> require single increments, then you would need to pass a 'u64 [2]' to
> get two iversions back.

Are you serious? What kind of boilerplate would that inflict on the
filesystems not, er, opting in for that... scalability improvement
experiment?