On Wed, 19 Feb 2025 at 18:58, Amir Goldstein <amir73il@xxxxxxxxx> wrote: > I circled back to this. I don't suppose you know of any patches > in the works? I'm not aware of any. > I was thinking about LOOKUP_HANDLE in the context of our > discussion at Plumbers on readdirplus passthrough. > > What we discussed is that kernel could instantiate some FUSE inodes > (populated during readdirplus passthrough) and at some later time, > kernel will notify server about those inodes via FUSE_INSTANTIATE > or similar command, which will instantiate a fuse server inode with > pre-defined nodeid. > > My thinking was to simplify a bit and require a 1-to-1 mapping > of kernel-server inode numbers to enable the feature of > FUSE_PASSTHOUGH_INODE (operations), meaning that > every FUSE inode has at least a potential backing inode which > reserves its inode number. > > But I think that 1-to-1 mapping of ino is not enough and to avoid > races it is better to have 1-to-1 mapping of file handles so > FUSE_INSTANTIATE would look a bit like LOOKUP_HANDLE > but "found" server inode must match the kernel's file handle. > > Is any of this making any sense to you? Not yet. I remember you explaining why FUSE_INSTANTIATE is needed, but I don't really remember. Can you please remind me how exactly you envision readdir/lookup passthrough? Thanks, Miklos
