On Wed, Jan 03, 2024 at 04:04:26PM -0300, Wedson Almeida Filho wrote: > On Wed, 3 Jan 2024 at 15:02, Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote: > > > > On Tue, Oct 31, 2023 at 05:14:08PM -0300, Wedson Almeida Filho wrote: > > > > Also, I see you're passing an inode to read_dir. Why did you decide to > > > > do that? There's information in the struct file that's either necessary > > > > or useful to have in the filesystem. Maybe not in toy filesystems, but eg > > > > network filesystems need user credentials to do readdir, which are stored > > > > in struct file. Block filesystems store readahead data in struct file. > > > > > > Because the two file systems we have don't use anything from `struct > > > file` beyond the inode. > > > > > > Passing a `file` to `read_dir` would require us to introduce an > > > unnecessary abstraction that no one uses, which we've been told not to > > > do. > > > > > > There is no technical reason that makes it impractical though. We can > > > add it when the need arises. > > > > Then we shouldn't merge any of this, or even send it out for review > > again until there is at least one non-toy filesystems implemented. > > 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. > > Either stick to the object orientation we've already defined (ie > > separate aops, iops, fops, ... with substantially similar arguments) > > or propose changes to the ones we have in C. Dealing only with toy > > filesystems is leading you to bad architecture. > > 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.
