From f5e291cf8328096d790f5416cf1968cb9164220a Mon Sep 17 00:00:00 2001 From: Florian Klink Date: Tue, 20 Jun 2023 01:17:13 +0200 Subject: feat(tvix/store/fuse): implement open explicitly This moves from stateless I/O to actually dealing with file handles, allowing the filesystem to keep reusing existing blobreaders, instead of opening a new reader on every read() call. Change-Id: I3fc35c071e4aee1021c8bbd58749d082b0abd188 Reviewed-on: https://cl.tvl.fyi/c/depot/+/8834 Tested-by: BuildkiteCI Reviewed-by: tazjin Autosubmit: flokli --- tvix/store/src/fuse/mod.rs | 102 ++++++++++++++++++++++++++++++++------------- 1 file changed, 72 insertions(+), 30 deletions(-) (limited to 'tvix/store') diff --git a/tvix/store/src/fuse/mod.rs b/tvix/store/src/fuse/mod.rs index ac0bf29dab09..6d796534b6e6 100644 --- a/tvix/store/src/fuse/mod.rs +++ b/tvix/store/src/fuse/mod.rs @@ -18,7 +18,7 @@ use crate::{ }; use fuser::{FileAttr, ReplyAttr, Request}; use nix_compat::store_path::StorePath; -use std::io::Read; +use std::io::{self, Read}; use std::sync::Arc; use std::{collections::HashMap, time::Duration}; use tracing::{debug, info_span, warn}; @@ -69,6 +69,11 @@ pub struct FUSE { /// This keeps track of inodes and data alongside them. inode_tracker: InodeTracker, + + /// This holds all open file handles + file_handles: HashMap>, + + next_file_handle: u64, } impl FUSE { @@ -84,6 +89,9 @@ impl FUSE { store_paths: HashMap::default(), inode_tracker: Default::default(), + + file_handles: Default::default(), + next_file_handle: 1, } } @@ -356,21 +364,10 @@ impl fuser::Filesystem for FUSE { } } - /// TODO: implement open + close? - - #[tracing::instrument(skip_all, fields(rq.inode = ino, rq.offset = offset, rq.size = size))] - fn read( - &mut self, - _req: &Request<'_>, - ino: u64, - _fh: u64, - offset: i64, - size: u32, - _flags: i32, - _lock_owner: Option, - reply: fuser::ReplyData, - ) { - debug!("read"); + #[tracing::instrument(skip_all, fields(rq.inode = ino))] + fn open(&mut self, _req: &Request<'_>, ino: u64, _flags: i32, reply: fuser::ReplyOpen) { + // get a new file handle + let fh = self.next_file_handle; if ino == fuser::FUSE_ROOT_ID { reply.error(libc::ENOSYS); @@ -397,26 +394,71 @@ impl fuser::Filesystem for FUSE { reply.error(libc::EIO); } Ok(Some(blob_reader)) => { - let data: std::io::Result> = blob_reader - .bytes() - // TODO: this is obviously terrible. blobreader should implement seek. - .skip(offset.try_into().unwrap()) - .take(size.try_into().unwrap()) - .collect(); - - match data { - Ok(data) => { - // respond with the requested data - reply.data(&data); - } - Err(e) => reply.error(e.raw_os_error().unwrap()), - } + self.file_handles.insert(fh, blob_reader); + reply.opened(fh, 0); + + // TODO: this will overflow after 2**64 operations, + // which is fine for now. + // See https://cl.tvl.fyi/c/depot/+/8834/comment/a6684ce0_d72469d1 + // for the discussion on alternatives. + self.next_file_handle += 1; } } } } } + #[tracing::instrument(skip_all, fields(rq.inode = ino, fh = fh))] + fn release( + &mut self, + _req: &Request<'_>, + ino: u64, + fh: u64, + _flags: i32, + _lock_owner: Option, + _flush: bool, + reply: fuser::ReplyEmpty, + ) { + // remove and get ownership on the blob reader + let blob_reader = self.file_handles.remove(&fh).unwrap(); + // drop it, which will close it. + drop(blob_reader); + + reply.ok(); + } + + #[tracing::instrument(skip_all, fields(rq.inode = ino, rq.offset = offset, rq.size = size))] + fn read( + &mut self, + _req: &Request<'_>, + ino: u64, + fh: u64, + offset: i64, + size: u32, + _flags: i32, + _lock_owner: Option, + reply: fuser::ReplyData, + ) { + debug!("read"); + + let blob_reader = self.file_handles.get_mut(&fh).unwrap(); + + let data: std::io::Result> = blob_reader + .bytes() + // TODO: this is obviously terrible. blobreader should implement seek. + .skip(offset.try_into().unwrap()) + .take(size.try_into().unwrap()) + .collect(); + + match data { + Ok(data) => { + // respond with the requested data + reply.data(&data); + } + Err(e) => reply.error(e.raw_os_error().unwrap()), + } + } + #[tracing::instrument(skip_all, fields(rq.inode = ino))] fn readlink(&mut self, _req: &Request<'_>, ino: u64, reply: fuser::ReplyData) { if ino == fuser::FUSE_ROOT_ID { -- cgit 1.4.1