On Tue, Jan 09, 2024 at 03:25:11PM -0300, Wedson Almeida Filho wrote: > On Wed, 3 Jan 2024 at 22:49, Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote: > > > What makes you characterize these filesystems as toys? The fact that > > > they only use the file's inode in iterate_shared? > > > > They're not real filesystems. You can't put, eg, root or your home > > directory on one of these filesystems. > > tarfs is a real file system, we use it to mount read-only container > layers on top of dm-verity for integrity. You're using it in production? Oh dear. > > > I'm trying to understand the argument here. Are saying that Rust > > > cannot have different APIs with the same performance characteristics > > > as C's, unless we also fix the C apis? > > > > > > That isn't even a requirement when introducing new C apis, why would > > > it be a requirement for Rust apis? > > > > I'm saying that we have the current object orientation (eg each inode > > is an object with inode methods) for a reason. Don't change it without > > understanding what that reason is. And moving, eg iterate_shared() from > > file_operations to struct file_system_type (effectively what you've done) > > is something we obviously wouldn't want to do. > > I don't think I'm changing anything. AFAICT, I'm adding a way to write > file systems in Rust. It uses the C API faithfully -- if you find ways > in which it doesn't, I'd be happy to fix them. You are changing the _object model_. The C API has separate objects for inodes, files, filesystems, superblocks, dentries, etc, etc. You've just smashed all of it together into a FileSystem which implements all of the inode, file, address_space, etc, etc ops. And this is the wrong approach.
