diff options
Diffstat (limited to 'tvix/castore/src')
| -rw-r--r-- | tvix/castore/src/fs/file_attr.rs | 53 | ||||
| -rw-r--r-- | tvix/castore/src/fs/fuse.rs | 113 | ||||
| -rw-r--r-- | tvix/castore/src/fs/inode_tracker.rs | 207 | ||||
| -rw-r--r-- | tvix/castore/src/fs/inodes.rs | 57 | ||||
| -rw-r--r-- | tvix/castore/src/fs/mod.rs | 627 | ||||
| -rw-r--r-- | tvix/castore/src/fs/root_nodes.rs | 18 | ||||
| -rw-r--r-- | tvix/castore/src/fs/virtiofs.rs | 237 | ||||
| -rw-r--r-- | tvix/castore/src/lib.rs | 4 |
8 files changed, 1316 insertions, 0 deletions
diff --git a/tvix/castore/src/fs/file_attr.rs b/tvix/castore/src/fs/file_attr.rs new file mode 100644 index 000000000000..ad41f036a253 --- /dev/null +++ b/tvix/castore/src/fs/file_attr.rs @@ -0,0 +1,53 @@ +#![allow(clippy::unnecessary_cast)] // libc::S_IFDIR is u32 on Linux and u16 on MacOS +use super::inodes::{DirectoryInodeData, InodeData}; +use fuse_backend_rs::abi::fuse_abi::Attr; + +/// The [Attr] describing the root +pub const ROOT_FILE_ATTR: Attr = Attr { + ino: fuse_backend_rs::api::filesystem::ROOT_ID, + size: 0, + blksize: 1024, + blocks: 0, + mode: libc::S_IFDIR as u32 | 0o555, + atime: 0, + mtime: 0, + ctime: 0, + atimensec: 0, + mtimensec: 0, + ctimensec: 0, + nlink: 0, + uid: 0, + gid: 0, + rdev: 0, + flags: 0, + #[cfg(target_os = "macos")] + crtime: 0, + #[cfg(target_os = "macos")] + crtimensec: 0, + #[cfg(target_os = "macos")] + padding: 0, +}; + +/// for given &Node and inode, construct an [Attr] +pub fn gen_file_attr(inode_data: &InodeData, inode: u64) -> Attr { + Attr { + ino: inode, + // FUTUREWORK: play with this numbers, as it affects read sizes for client applications. + blocks: 1024, + size: match inode_data { + InodeData::Regular(_, size, _) => *size as u64, + InodeData::Symlink(target) => target.len() as u64, + InodeData::Directory(DirectoryInodeData::Sparse(_, size)) => *size as u64, + InodeData::Directory(DirectoryInodeData::Populated(_, ref children)) => { + children.len() as u64 + } + }, + mode: match inode_data { + InodeData::Regular(_, _, false) => libc::S_IFREG as u32 | 0o444, // no-executable files + InodeData::Regular(_, _, true) => libc::S_IFREG as u32 | 0o555, // executable files + InodeData::Symlink(_) => libc::S_IFLNK as u32 | 0o444, + InodeData::Directory(_) => libc::S_IFDIR as u32 | 0o555, + }, + ..Default::default() + } +} diff --git a/tvix/castore/src/fs/fuse.rs b/tvix/castore/src/fs/fuse.rs new file mode 100644 index 000000000000..98793bf47d58 --- /dev/null +++ b/tvix/castore/src/fs/fuse.rs @@ -0,0 +1,113 @@ +use std::{io, path::Path, sync::Arc, thread}; + +use fuse_backend_rs::{api::filesystem::FileSystem, transport::FuseSession}; +use tracing::error; + +struct FuseServer<FS> +where + FS: FileSystem + Sync + Send, +{ + server: Arc<fuse_backend_rs::api::server::Server<Arc<FS>>>, + channel: fuse_backend_rs::transport::FuseChannel, +} + +#[cfg(target_os = "macos")] +const BADFD: libc::c_int = libc::EBADF; +#[cfg(target_os = "linux")] +const BADFD: libc::c_int = libc::EBADFD; + +impl<FS> FuseServer<FS> +where + FS: FileSystem + Sync + Send, +{ + fn start(&mut self) -> io::Result<()> { + while let Some((reader, writer)) = self + .channel + .get_request() + .map_err(|_| io::Error::from_raw_os_error(libc::EINVAL))? + { + if let Err(e) = self + .server + .handle_message(reader, writer.into(), None, None) + { + match e { + // This indicates the session has been shut down. + fuse_backend_rs::Error::EncodeMessage(e) if e.raw_os_error() == Some(BADFD) => { + break; + } + error => { + error!(?error, "failed to handle fuse request"); + continue; + } + } + } + } + Ok(()) + } +} + +pub struct FuseDaemon { + session: FuseSession, + threads: Vec<thread::JoinHandle<()>>, +} + +impl FuseDaemon { + pub fn new<FS, P>(fs: FS, mountpoint: P, threads: usize) -> Result<Self, io::Error> + where + FS: FileSystem + Sync + Send + 'static, + P: AsRef<Path>, + { + let server = Arc::new(fuse_backend_rs::api::server::Server::new(Arc::new(fs))); + + let mut session = FuseSession::new(mountpoint.as_ref(), "tvix-store", "", true) + .map_err(|e| io::Error::new(io::ErrorKind::Other, e.to_string()))?; + + #[cfg(target_os = "linux")] + session.set_allow_other(false); + session + .mount() + .map_err(|e| io::Error::new(io::ErrorKind::Other, e.to_string()))?; + let mut join_handles = Vec::with_capacity(threads); + for _ in 0..threads { + let mut server = FuseServer { + server: server.clone(), + channel: session + .new_channel() + .map_err(|e| io::Error::new(io::ErrorKind::Other, e.to_string()))?, + }; + let join_handle = thread::Builder::new() + .name("fuse_server".to_string()) + .spawn(move || { + let _ = server.start(); + })?; + join_handles.push(join_handle); + } + + Ok(FuseDaemon { + session, + threads: join_handles, + }) + } + + pub fn unmount(&mut self) -> Result<(), io::Error> { + self.session + .umount() + .map_err(|e| io::Error::new(io::ErrorKind::Other, e.to_string()))?; + + for thread in self.threads.drain(..) { + thread.join().map_err(|_| { + io::Error::new(io::ErrorKind::Other, "failed to join fuse server thread") + })?; + } + + Ok(()) + } +} + +impl Drop for FuseDaemon { + fn drop(&mut self) { + if let Err(error) = self.unmount() { + error!(?error, "failed to unmont fuse filesystem") + } + } +} diff --git a/tvix/castore/src/fs/inode_tracker.rs b/tvix/castore/src/fs/inode_tracker.rs new file mode 100644 index 000000000000..4a8283b6b144 --- /dev/null +++ b/tvix/castore/src/fs/inode_tracker.rs @@ -0,0 +1,207 @@ +use std::{collections::HashMap, sync::Arc}; + +use super::inodes::{DirectoryInodeData, InodeData}; +use crate::B3Digest; + +/// InodeTracker keeps track of inodes, stores data being these inodes and deals +/// with inode allocation. +pub struct InodeTracker { + data: HashMap<u64, Arc<InodeData>>, + + // lookup table for blobs by their B3Digest + blob_digest_to_inode: HashMap<B3Digest, u64>, + + // lookup table for symlinks by their target + symlink_target_to_inode: HashMap<bytes::Bytes, u64>, + + // lookup table for directories by their B3Digest. + // Note the corresponding directory may not be present in data yet. + directory_digest_to_inode: HashMap<B3Digest, u64>, + + // the next inode to allocate + next_inode: u64, +} + +impl Default for InodeTracker { + fn default() -> Self { + Self { + data: Default::default(), + + blob_digest_to_inode: Default::default(), + symlink_target_to_inode: Default::default(), + directory_digest_to_inode: Default::default(), + + next_inode: 2, + } + } +} + +impl InodeTracker { + // Retrieves data for a given inode, if it exists. + pub fn get(&self, ino: u64) -> Option<Arc<InodeData>> { + self.data.get(&ino).cloned() + } + + // Replaces data for a given inode. + // Panics if the inode doesn't already exist. + pub fn replace(&mut self, ino: u64, data: Arc<InodeData>) { + if self.data.insert(ino, data).is_none() { + panic!("replace called on unknown inode"); + } + } + + // Stores data and returns the inode for it. + // In case an inode has already been allocated for the same data, that inode + // is returned, otherwise a new one is allocated. + // In case data is a [InodeData::Directory], inodes for all items are looked + // up + pub fn put(&mut self, data: InodeData) -> u64 { + match data { + InodeData::Regular(ref digest, _, _) => { + match self.blob_digest_to_inode.get(digest) { + Some(found_ino) => { + // We already have it, return the inode. + *found_ino + } + None => self.insert_and_increment(data), + } + } + InodeData::Symlink(ref target) => { + match self.symlink_target_to_inode.get(target) { + Some(found_ino) => { + // We already have it, return the inode. + *found_ino + } + None => self.insert_and_increment(data), + } + } + InodeData::Directory(DirectoryInodeData::Sparse(ref digest, _size)) => { + // check the lookup table if the B3Digest is known. + match self.directory_digest_to_inode.get(digest) { + Some(found_ino) => { + // We already have it, return the inode. + *found_ino + } + None => { + // insert and return the inode + self.insert_and_increment(data) + } + } + } + // Inserting [DirectoryInodeData::Populated] doesn't normally happen, + // only via [replace]. + InodeData::Directory(DirectoryInodeData::Populated(..)) => { + unreachable!("should never be called with DirectoryInodeData::Populated") + } + } + } + + // Inserts the data and returns the inode it was stored at, while + // incrementing next_inode. + fn insert_and_increment(&mut self, data: InodeData) -> u64 { + let ino = self.next_inode; + // insert into lookup tables + match data { + InodeData::Regular(ref digest, _, _) => { + self.blob_digest_to_inode.insert(digest.clone(), ino); + } + InodeData::Symlink(ref target) => { + self.symlink_target_to_inode.insert(target.clone(), ino); + } + InodeData::Directory(DirectoryInodeData::Sparse(ref digest, _size)) => { + self.directory_digest_to_inode.insert(digest.clone(), ino); + } + // This is currently not used outside test fixtures. + // Usually a [DirectoryInodeData::Sparse] is inserted and later + // "upgraded" with more data. + // However, as a future optimization, a lookup for a PathInfo could trigger a + // [DirectoryService::get_recursive()] request that "forks into + // background" and prepopulates all Directories in a closure. + InodeData::Directory(DirectoryInodeData::Populated(ref digest, _)) => { + self.directory_digest_to_inode.insert(digest.clone(), ino); + } + } + // Insert data + self.data.insert(ino, Arc::new(data)); + + // increment inode counter and return old inode. + self.next_inode += 1; + ino + } +} + +#[cfg(test)] +mod tests { + use crate::fixtures; + + use super::InodeData; + use super::InodeTracker; + + /// Getting something non-existent should be none + #[test] + fn get_nonexistent() { + let inode_tracker = InodeTracker::default(); + assert!(inode_tracker.get(1).is_none()); + } + + /// Put of a regular file should allocate a uid, which should be the same when inserting again. + #[test] + fn put_regular() { + let mut inode_tracker = InodeTracker::default(); + let f = InodeData::Regular( + fixtures::BLOB_A_DIGEST.clone(), + fixtures::BLOB_A.len() as u64, + false, + ); + + // put it in + let ino = inode_tracker.put(f.clone()); + + // a get should return the right data + let data = inode_tracker.get(ino).expect("must be some"); + match *data { + InodeData::Regular(ref digest, _, _) => { + assert_eq!(&fixtures::BLOB_A_DIGEST.clone(), digest); + } + InodeData::Symlink(_) | InodeData::Directory(..) => panic!("wrong type"), + } + + // another put should return the same ino + assert_eq!(ino, inode_tracker.put(f)); + + // inserting another file should return a different ino + assert_ne!( + ino, + inode_tracker.put(InodeData::Regular( + fixtures::BLOB_B_DIGEST.clone(), + fixtures::BLOB_B.len() as u64, + false, + )) + ); + } + + // Put of a symlink should allocate a uid, which should be the same when inserting again + #[test] + fn put_symlink() { + let mut inode_tracker = InodeTracker::default(); + let f = InodeData::Symlink("target".into()); + + // put it in + let ino = inode_tracker.put(f.clone()); + + // a get should return the right data + let data = inode_tracker.get(ino).expect("must be some"); + match *data { + InodeData::Symlink(ref target) => { + assert_eq!(b"target".to_vec(), *target); + } + InodeData::Regular(..) | InodeData::Directory(..) => panic!("wrong type"), + } + + // another put should return the same ino + assert_eq!(ino, inode_tracker.put(f)); + + // inserting another file should return a different ino + assert_ne!(ino, inode_tracker.put(InodeData::Symlink("target2".into()))); + } +} diff --git a/tvix/castore/src/fs/inodes.rs b/tvix/castore/src/fs/inodes.rs new file mode 100644 index 000000000000..9131b703bae0 --- /dev/null +++ b/tvix/castore/src/fs/inodes.rs @@ -0,0 +1,57 @@ +//! This module contains all the data structures used to track information +//! about inodes, which present tvix-castore nodes in a filesystem. +use crate::proto as castorepb; +use crate::B3Digest; + +#[derive(Clone, Debug)] +pub enum InodeData { + Regular(B3Digest, u64, bool), // digest, size, executable + Symlink(bytes::Bytes), // target + Directory(DirectoryInodeData), // either [DirectoryInodeData:Sparse] or [DirectoryInodeData:Populated] +} + +/// This encodes the two different states of [InodeData::Directory]. +/// Either the data still is sparse (we only saw a [castorepb::DirectoryNode], +/// but didn't fetch the [castorepb::Directory] struct yet, or we processed a +/// lookup and did fetch the data. +#[derive(Clone, Debug)] +pub enum DirectoryInodeData { + Sparse(B3Digest, u64), // digest, size + Populated(B3Digest, Vec<(u64, castorepb::node::Node)>), // [(child_inode, node)] +} + +impl From<&castorepb::node::Node> for InodeData { + fn from(value: &castorepb::node::Node) -> Self { + match value { + castorepb::node::Node::Directory(directory_node) => directory_node.into(), + castorepb::node::Node::File(file_node) => file_node.into(), + castorepb::node::Node::Symlink(symlink_node) => symlink_node.into(), + } + } +} + +impl From<&castorepb::SymlinkNode> for InodeData { + fn from(value: &castorepb::SymlinkNode) -> Self { + InodeData::Symlink(value.target.clone()) + } +} + +impl From<&castorepb::FileNode> for InodeData { + fn from(value: &castorepb::FileNode) -> Self { + InodeData::Regular( + value.digest.clone().try_into().unwrap(), + value.size, + value.executable, + ) + } +} + +/// Converts a DirectoryNode to a sparsely populated InodeData::Directory. +impl From<&castorepb::DirectoryNode> for InodeData { + fn from(value: &castorepb::DirectoryNode) -> Self { + InodeData::Directory(DirectoryInodeData::Sparse( + value.digest.clone().try_into().unwrap(), + value.size, + )) + } +} diff --git a/tvix/castore/src/fs/mod.rs b/tvix/castore/src/fs/mod.rs new file mode 100644 index 000000000000..9bd021cb09fe --- /dev/null +++ b/tvix/castore/src/fs/mod.rs @@ -0,0 +1,627 @@ +mod file_attr; +mod inode_tracker; +mod inodes; +mod root_nodes; + +#[cfg(feature = "fuse")] +pub mod fuse; + +#[cfg(feature = "virtiofs")] +pub mod virtiofs; + +use crate::proto as castorepb; +use crate::{ + blobservice::{BlobReader, BlobService}, + directoryservice::DirectoryService, + proto::{node::Node, NamedNode}, + B3Digest, +}; +use fuse_backend_rs::abi::fuse_abi::stat64; +use fuse_backend_rs::api::filesystem::{Context, FileSystem, FsOptions, ROOT_ID}; +use futures::StreamExt; +use parking_lot::RwLock; +use std::ops::Deref; +use std::{ + collections::HashMap, + io, + sync::atomic::AtomicU64, + sync::{atomic::Ordering, Arc}, + time::Duration, +}; +use tokio::{ + io::{AsyncReadExt, AsyncSeekExt}, + sync::mpsc, +}; +use tracing::{debug, info_span, instrument, warn}; + +pub use self::root_nodes::RootNodes; +use self::{ + file_attr::{gen_file_attr, ROOT_FILE_ATTR}, + inode_tracker::InodeTracker, + inodes::{DirectoryInodeData, InodeData}, +}; + +/// This implements a read-only FUSE filesystem for a tvix-store +/// with the passed [BlobService], [DirectoryService] and [RootNodes]. +/// +/// Linux uses inodes in filesystems. When implementing FUSE, most calls are +/// *for* a given inode. +/// +/// This means, we need to have a stable mapping of inode numbers to the +/// corresponding store nodes. +/// +/// We internally delegate all inode allocation and state keeping to the +/// inode tracker. +/// We store a mapping from currently "explored" names in the root to their +/// inode. +/// +/// There's some places where inodes are allocated / data inserted into +/// the inode tracker, if not allocated before already: +/// - Processing a `lookup` request, either in the mount root, or somewhere +/// deeper. +/// - Processing a `readdir` request +/// +/// Things pointing to the same contents get the same inodes, irrespective of +/// their own location. +/// This means: +/// - Symlinks with the same target will get the same inode. +/// - Regular/executable files with the same contents will get the same inode +/// - Directories with the same contents will get the same inode. +/// +/// Due to the above being valid across the whole store, and considering the +/// merkle structure is a DAG, not a tree, this also means we can't do "bucketed +/// allocation", aka reserve Directory.size inodes for each directory node we +/// explore. +/// Tests for this live in the tvix-store crate. +pub struct TvixStoreFs<BS, DS, RN> { + blob_service: BS, + directory_service: DS, + root_nodes_provider: RN, + + /// Whether to (try) listing elements in the root. + list_root: bool, + + /// This maps a given basename in the root to the inode we allocated for the node. + root_nodes: RwLock<HashMap<Vec<u8>, u64>>, + + /// This keeps track of inodes and data alongside them. + inode_tracker: RwLock<InodeTracker>, + + /// This holds all open file handles + #[allow(clippy::type_complexity)] + file_handles: RwLock<HashMap<u64, Arc<tokio::sync::Mutex<Box<dyn BlobReader>>>>>, + + next_file_handle: AtomicU64, + + tokio_handle: tokio::runtime::Handle, +} + +impl<BS, DS, RN> TvixStoreFs<BS, DS, RN> +where + BS: Deref<Target = dyn BlobService> + Clone + Send, + DS: Deref<Target = dyn DirectoryService> + Clone + Send + 'static, + RN: RootNodes + Clone + 'static, +{ + pub fn new( + blob_service: BS, + directory_service: DS, + root_nodes_provider: RN, + list_root: bool, + ) -> Self { + Self { + blob_service, + directory_service, + root_nodes_provider, + + list_root, + + root_nodes: RwLock::new(HashMap::default()), + inode_tracker: RwLock::new(Default::default()), + + file_handles: RwLock::new(Default::default()), + next_file_handle: AtomicU64::new(1), + tokio_handle: tokio::runtime::Handle::current(), + } + } + + /// Retrieves the inode for a given root node basename, if present. + /// This obtains a read lock on self.root_nodes. + fn get_inode_for_root_name(&self, name: &[u8]) -> Option<u64> { + self.root_nodes.read().get(name).cloned() + } + + /// For a given inode, look up the given directory behind it (from + /// self.inode_tracker), and return its children. + /// The inode_tracker MUST know about this inode already, and it MUST point + /// to a [InodeData::Directory]. + /// It is ok if it's a [DirectoryInodeData::Sparse] - in that case, a lookup + /// in self.directory_service is performed, and self.inode_tracker is updated with the + /// [DirectoryInodeData::Populated]. + #[instrument(skip(self), err)] + fn get_directory_children(&self, ino: u64) -> io::Result<(B3Digest, Vec<(u64, Node)>)> { + let data = self.inode_tracker.read().get(ino).unwrap(); + match *data { + // if it's populated already, return children. + InodeData::Directory(DirectoryInodeData::Populated( + ref parent_digest, + ref children, + )) => Ok((parent_digest.clone(), children.clone())), + // if it's sparse, fetch data using directory_service, populate child nodes + // and update it in [self.inode_tracker]. + InodeData::Directory(DirectoryInodeData::Sparse(ref parent_digest, _)) => { + let directory = self + .tokio_handle + .block_on(self.tokio_handle.spawn({ + let directory_service = self.directory_service.clone(); + let parent_digest = parent_digest.to_owned(); + async move { directory_service.get(&parent_digest).await } + })) + .unwrap()? + .ok_or_else(|| { + warn!(directory.digest=%parent_digest, "directory not found"); + // If the Directory can't be found, this is a hole, bail out. + io::Error::from_raw_os_error(libc::EIO) + })?; + + // Turn the retrieved directory into a InodeData::Directory(DirectoryInodeData::Populated(..)), + // allocating inodes for the children on the way. + let children = { + let mut inode_tracker = self.inode_tracker.write(); + + let children: Vec<(u64, castorepb::node::Node)> = directory + .nodes() + .map(|child_node| { + let child_ino = inode_tracker.put((&child_node).into()); + (child_ino, child_node) + }) + .collect(); + + // replace. + inode_tracker.replace( + ino, + Arc::new(InodeData::Directory(DirectoryInodeData::Populated( + parent_digest.clone(), + children.clone(), + ))), + ); + + children + }; + + Ok((parent_digest.clone(), children)) + } + // if the parent inode was not a directory, this doesn't make sense + InodeData::Regular(..) | InodeData::Symlink(_) => { + Err(io::Error::from_raw_os_error(libc::ENOTDIR)) + } + } + } + + /// This will turn a lookup request for a name in the root to a ino and + /// [InodeData]. + /// It will peek in [self.root_nodes], and then either look it up from + /// [self.inode_tracker], + /// or otherwise fetch from [self.root_nodes], and then insert into + /// [self.inode_tracker]. + /// In the case the name can't be found, a libc::ENOENT is returned. + fn name_in_root_to_ino_and_data( + &self, + name: &std::ffi::CStr, + ) -> io::Result<(u64, Arc<InodeData>)> { + // Look up the inode for that root node. + // If there's one, [self.inode_tracker] MUST also contain the data, + // which we can then return. + if let Some(inode) = self.get_inode_for_root_name(name.to_bytes()) { + return Ok(( + inode, + self.inode_tracker + .read() + .get(inode) + .expect("must exist") + .to_owned(), + )); + } + + // We don't have it yet, look it up in [self.root_nodes]. + match self.tokio_handle.block_on({ + let root_nodes_provider = self.root_nodes_provider.clone(); + async move { root_nodes_provider.get_by_basename(name.to_bytes()).await } + }) { + // if there was an error looking up the root node, propagate up an IO error. + Err(_e) => Err(io::Error::from_raw_os_error(libc::EIO)), + // the root node doesn't exist, so the file doesn't exist. + Ok(None) => Err(io::Error::from_raw_os_error(libc::ENOENT)), + // The root node does exist + Ok(Some(root_node)) => { + // The name must match what's passed in the lookup, otherwise this is also a ENOENT. + if root_node.get_name() != name.to_bytes() { + debug!(root_node.name=?root_node.get_name(), found_node.name=%name.to_string_lossy(), "node name mismatch"); + return Err(io::Error::from_raw_os_error(libc::ENOENT)); + } + + // Let's check if someone else beat us to updating the inode tracker and + // root_nodes map. This avoids locking inode_tracker for writing. + if let Some(ino) = self.root_nodes.read().get(name.to_bytes()) { + return Ok(( + *ino, + self.inode_tracker.read().get(*ino).expect("must exist"), + )); + } + + // Only in case it doesn't, lock [self.root_nodes] and + // [self.inode_tracker] for writing. + let mut root_nodes = self.root_nodes.write(); + let mut inode_tracker = self.inode_tracker.write(); + + // insert the (sparse) inode data and register in + // self.root_nodes. + let inode_data: InodeData = (&root_node).into(); + let ino = inode_tracker.put(inode_data.clone()); + root_nodes.insert(name.to_bytes().into(), ino); + + Ok((ino, Arc::new(inode_data))) + } + } + } +} + +impl<BS, DS, RN> FileSystem for TvixStoreFs<BS, DS, RN> +where + BS: Deref<Target = dyn BlobService> + Clone + Send + 'static, + DS: Deref<Target = dyn DirectoryService> + Send + Clone + 'static, + RN: RootNodes + Clone + 'static, +{ + type Handle = u64; + type Inode = u64; + + fn init(&self, _capable: FsOptions) -> io::Result<FsOptions> { + Ok(FsOptions::empty()) + } + + #[tracing::instrument(skip_all, fields(rq.inode = inode))] + fn getattr( + &self, + _ctx: &Context, + inode: Self::Inode, + _handle: Option<Self::Handle>, + ) -> io::Result<(stat64, Duration)> { + if inode == ROOT_ID { + return Ok((ROOT_FILE_ATTR.into(), Duration::MAX)); + } + + match self.inode_tracker.read().get(inode) { + None => Err(io::Error::from_raw_os_error(libc::ENOENT)), + Some(node) => { + debug!(node = ?node, "found node"); + Ok((gen_file_attr(&node, inode).into(), Duration::MAX)) + } + } + } + + #[tracing::instrument(skip_all, fields(rq.parent_inode = parent, rq.name = ?name))] + fn lookup( + &self, + _ctx: &Context, + parent: Self::Inode, + name: &std::ffi::CStr, + ) -> io::Result<fuse_backend_rs::api::filesystem::Entry> { + debug!("lookup"); + + // This goes from a parent inode to a node. + // - If the parent is [ROOT_ID], we need to check + // [self.root_nodes] (fetching from a [RootNode] provider if needed) + // - Otherwise, lookup the parent in [self.inode_tracker] (which must be + // a [InodeData::Directory]), and find the child with that name. + if parent == ROOT_ID { + let (ino, inode_data) = self.name_in_root_to_ino_and_data(name)?; + + debug!(inode_data=?&inode_data, ino=ino, "Some"); + return Ok(fuse_backend_rs::api::filesystem::Entry { + inode: ino, + attr: gen_file_attr(&inode_data, ino).into(), + attr_timeout: Duration::MAX, + entry_timeout: Duration::MAX, + ..Default::default() + }); + } + // This is the "lookup for "a" inside inode 42. + // We already know that inode 42 must be a directory. + let (parent_digest, children) = self.get_directory_children(parent)?; + + let span = info_span!("lookup", directory.digest = %parent_digest); + let _enter = span.enter(); + + // Search for that name in the list of children and return the FileAttrs. + + // in the children, find the one with the desired name. + if let Some((child_ino, _)) = children.iter().find(|e| e.1.get_name() == name.to_bytes()) { + // lookup the child [InodeData] in [self.inode_tracker]. + // We know the inodes for children have already been allocated. + let child_inode_data = self.inode_tracker.read().get(*child_ino).unwrap(); + + // Reply with the file attributes for the child. + // For child directories, we still have all data we need to reply. + Ok(fuse_backend_rs::api::filesystem::Entry { + inode: *child_ino, + attr: gen_file_attr(&child_inode_data, *child_ino).into(), + attr_timeout: Duration::MAX, + entry_timeout: Duration::MAX, + ..Default::default() + }) + } else { + // Child not found, return ENOENT. + Err(io::Error::from_raw_os_error(libc::ENOENT)) + } + } + + // TODO: readdirplus? + + #[tracing::instrument(skip_all, fields(rq.inode = inode, rq.offset = offset))] + fn readdir( + &self, + _ctx: &Context, + inode: Self::Inode, + _handle: Self::Handle, + _size: u32, + offset: u64, + add_entry: &mut dyn FnMut(fuse_backend_rs::api::filesystem::DirEntry) -> io::Result<usize>, + ) -> io::Result<()> { + debug!("readdir"); + + if inode == ROOT_ID { + if !self.list_root { + return Err(io::Error::from_raw_os_error(libc::EPERM)); // same error code as ipfs/kubo + } else { + let root_nodes_provider = self.root_nodes_provider.clone(); + let (tx, mut rx) = mpsc::channel(16); + + // This task will run in the background immediately and will exit + // after the stream ends or if we no longer want any more entries. + self.tokio_handle.spawn(async move { + let mut stream = root_nodes_provider.list().skip(offset as usize).enumerate(); + while let Some(node) = stream.next().await { + if tx.send(node).await.is_err() { + // If we get a send error, it means the sync code + // doesn't want any more entries. + break; + } + } + }); + + while let Some((i, root_node)) = rx.blocking_recv() { + let root_node = match root_node { + Err(e) => { + warn!("failed to retrieve pathinfo: {}", e); + return Err(io::Error::from_raw_os_error(libc::EPERM)); + } + Ok(root_node) => root_node, + }; + + let name = root_node.get_name(); + // obtain the inode, or allocate a new one. + let ino = self.get_inode_for_root_name(name).unwrap_or_else(|| { + // insert the (sparse) inode data and register in + // self.root_nodes. + let ino = self.inode_tracker.write().put((&root_node).into()); + self.root_nodes.write().insert(name.into(), ino); + ino + }); + + let ty = match root_node { + Node::Directory(_) => libc::S_IFDIR, + Node::File(_) => libc::S_IFREG, + Node::Symlink(_) => libc::S_IFLNK, + }; + + let written = add_entry(fuse_backend_rs::api::filesystem::DirEntry { + ino, + offset: offset + i as u64 + 1, + type_: ty, + name, + })?; + // If the buffer is full, add_entry will return `Ok(0)`. + if written == 0 { + break; + } + } + + return Ok(()); + } + } + + // lookup the children, or return an error if it's not a directory. + let (parent_digest, children) = self.get_directory_children(inode)?; + + let span = info_span!("lookup", directory.digest = %parent_digest); + let _enter = span.enter(); + + for (i, (ino, child_node)) in children.iter().skip(offset as usize).enumerate() { + // the second parameter will become the "offset" parameter on the next call. + let written = add_entry(fuse_backend_rs::api::filesystem::DirEntry { + ino: *ino, + offset: offset + i as u64 + 1, + type_: match child_node { + #[allow(clippy::unnecessary_cast)] + // libc::S_IFDIR is u32 on Linux and u16 on MacOS + Node::Directory(_) => libc::S_IFDIR as u32, + #[allow(clippy::unnecessary_cast)] + // libc::S_IFDIR is u32 on Linux and u16 on MacOS + Node::File(_) => libc::S_IFREG as u32, + #[allow(clippy::unnecessary_cast)] + // libc::S_IFDIR is u32 on Linux and u16 on MacOS + Node::Symlink(_) => libc::S_IFLNK as u32, + }, + name: child_node.get_name(), + })?; + // If the buffer is full, add_entry will return `Ok(0)`. + if written == 0 { + break; + } + } + + Ok(()) + } + + #[tracing::instrument(skip_all, fields(rq.inode = inode))] + fn open( + &self, + _ctx: &Context, + inode: Self::Inode, + _flags: u32, + _fuse_flags: u32, + ) -> io::Result<( + Option<Self::Handle>, + fuse_backend_rs::api::filesystem::OpenOptions, + )> { + if inode == ROOT_ID { + return Err(io::Error::from_raw_os_error(libc::ENOSYS)); + } + + // lookup the inode + match *self.inode_tracker.read().get(inode).unwrap() { + // read is invalid on non-files. + InodeData::Directory(..) | InodeData::Symlink(_) => { + warn!("is directory"); + Err(io::Error::from_raw_os_error(libc::EISDIR)) + } + InodeData::Regular(ref blob_digest, _blob_size, _) => { + let span = info_span!("read", blob.digest = %blob_digest); + let _enter = span.enter(); + + let blob_service = self.blob_service.clone(); + let blob_digest = blob_digest.clone(); + + let task = self + .tokio_handle + .spawn(async move { blob_service.open_read(&blob_digest).await }); + + let blob_reader = self.tokio_handle.block_on(task).unwrap(); + + match blob_reader { + Ok(None) => { + warn!("blob not found"); + Err(io::Error::from_raw_os_error(libc::EIO)) + } + Err(e) => { + warn!(e=?e, "error opening blob"); + Err(io::Error::from_raw_os_error(libc::EIO)) + } + Ok(Some(blob_reader)) => { + // get a new file handle + // 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. + let fh = self.next_file_handle.fetch_add(1, Ordering::SeqCst); + + debug!("add file handle {}", fh); + self.file_handles + .write() + .insert(fh, Arc::new(tokio::sync::Mutex::new(blob_reader))); + + Ok(( + Some(fh), + fuse_backend_rs::api::filesystem::OpenOptions::empty(), + )) + } + } + } + } + } + + #[tracing::instrument(skip_all, fields(rq.inode = inode, fh = handle))] + fn release( + &self, + _ctx: &Context, + inode: Self::Inode, + _flags: u32, + handle: Self::Handle, + _flush: bool, + _flock_release: bool, + _lock_owner: Option<u64>, + ) -> io::Result<()> { + // remove and get ownership on the blob reader + match self.file_handles.write().remove(&handle) { + // drop it, which will close it. + Some(blob_reader) => drop(blob_reader), + None => { + // These might already be dropped if a read error occured. + debug!("file_handle {} not found", handle); + } + } + + Ok(()) + } + + #[tracing::instrument(skip_all, fields(rq.inode = inode, rq.offset = offset, rq.size = size))] + fn read( + &self, + _ctx: &Context, + inode: Self::Inode, + handle: Self::Handle, + w: &mut dyn fuse_backend_rs::api::filesystem::ZeroCopyWriter, + size: u32, + offset: u64, + _lock_owner: Option<u64>, + _flags: u32, + ) -> io::Result<usize> { + debug!("read"); + + // We need to take out the blob reader from self.file_handles, so we can + // interact with it in the separate task. + // On success, we pass it back out of the task, so we can put it back in self.file_handles. + let blob_reader = match self.file_handles.read().get(&handle) { + Some(blob_reader) => blob_reader.clone(), + None => { + warn!("file handle {} unknown", handle); + return Err(io::Error::from_raw_os_error(libc::EIO)); + } + }; + + let task = self.tokio_handle.spawn(async move { + let mut blob_reader = blob_reader.lock().await; + + // seek to the offset specified, which is relative to the start of the file. + let resp = blob_reader.seek(io::SeekFrom::Start(offset)).await; + + match resp { + Ok(pos) => { + debug_assert_eq!(offset, pos); + } + Err(e) => { + warn!("failed to seek to offset {}: {}", offset, e); + return Err(io::Error::from_raw_os_error(libc::EIO)); + } + } + + // As written in the fuse docs, read should send exactly the number + // of bytes requested except on EOF or error. + + let mut buf: Vec<u8> = Vec::with_capacity(size as usize); + + // copy things from the internal buffer into buf to fill it till up until size + tokio::io::copy(&mut blob_reader.as_mut().take(size as u64), &mut buf).await?; + + Ok(buf) + }); + + let buf = self.tokio_handle.block_on(task).unwrap()?; + + w.write(&buf) + } + + #[tracing::instrument(skip_all, fields(rq.inode = inode))] + fn readlink(&self, _ctx: &Context, inode: Self::Inode) -> io::Result<Vec<u8>> { + if inode == ROOT_ID { + return Err(io::Error::from_raw_os_error(libc::ENOSYS)); + } + + // lookup the inode + match *self.inode_tracker.read().get(inode).unwrap() { + InodeData::Directory(..) | InodeData::Regular(..) => { + Err(io::Error::from_raw_os_error(libc::EINVAL)) + } + InodeData::Symlink(ref target) => Ok(target.to_vec()), + } + } +} diff --git a/tvix/castore/src/fs/root_nodes.rs b/tvix/castore/src/fs/root_nodes.rs new file mode 100644 index 000000000000..8d27b477ff69 --- /dev/null +++ b/tvix/castore/src/fs/root_nodes.rs @@ -0,0 +1,18 @@ +use std::pin::Pin; + +use crate::{proto::node::Node, Error}; +use futures::Stream; +use tonic::async_trait; + +/// Provides an interface for looking up root nodes in tvix-castore by given +/// a lookup key (usually the basename), and optionally allow a listing. +#[async_trait] +pub trait RootNodes: Send + Sync { + /// Looks up a root CA node based on the basename of the node in the root + /// directory of the filesystem. + async fn get_by_basename(&self, name: &[u8]) -> Result<Option<Node>, Error>; + + /// Lists all root CA nodes in the filesystem. An error can be returned + /// in case listing is not allowed + fn list(&self) -> Pin<Box<dyn Stream<Item = Result<Node, Error>> + Send>>; +} diff --git a/tvix/castore/src/fs/virtiofs.rs b/tvix/castore/src/fs/virtiofs.rs new file mode 100644 index 000000000000..846270d28568 --- /dev/null +++ b/tvix/castore/src/fs/virtiofs.rs @@ -0,0 +1,237 @@ +use std::{ + convert, error, fmt, io, + ops::Deref, + path::Path, + sync::{Arc, MutexGuard, RwLock}, +}; + +use fuse_backend_rs::{ + api::{filesystem::FileSystem, server::Server}, + transport::{FsCacheReqHandler, Reader, VirtioFsWriter}, +}; +use tracing::error; +use vhost::vhost_user::{ + Listener, SlaveFsCacheReq, VhostUserProtocolFeatures, VhostUserVirtioFeatures, +}; +use vhost_user_backend::{VhostUserBackendMut, VhostUserDaemon, VringMutex, VringState, VringT}; +use virtio_bindings::bindings::virtio_ring::{ + VIRTIO_RING_F_EVENT_IDX, VIRTIO_RING_F_INDIRECT_DESC, +}; +use virtio_queue::QueueT; +use vm_memory::{GuestAddressSpace, GuestMemoryAtomic, GuestMemoryMmap}; +use vmm_sys_util::epoll::EventSet; + +const VIRTIO_F_VERSION_1: u32 = 32; +const NUM_QUEUES: usize = 2; +const QUEUE_SIZE: usize = 1024; + +#[derive(Debug)] +enum Error { + /// Failed to handle non-input event. + HandleEventNotEpollIn, + /// Failed to handle unknown event. + HandleEventUnknownEvent, + /// Invalid descriptor chain. + InvalidDescriptorChain, + /// Failed to handle filesystem requests. + HandleRequests(fuse_backend_rs::Error), + /// Failed to construct new vhost user daemon. + NewDaemon, + /// Failed to start the vhost user daemon. + StartDaemon, + /// Failed to wait for the vhost user daemon. + WaitDaemon, +} + +impl fmt::Display for Error { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + write!(f, "vhost_user_fs_error: {self:?}") + } +} + +impl error::Error for Error {} + +impl convert::From<Error> for io::Error { + fn from(e: Error) -> Self { + io::Error::new(io::ErrorKind::Other, e) + } +} + +struct VhostUserFsBackend<FS> +where + FS: FileSystem + Send + Sync, +{ + server: Arc<Server<Arc<FS>>>, + event_idx: bool, + guest_mem: GuestMemoryAtomic<GuestMemoryMmap>, + cache_req: Option<SlaveFsCacheReq>, +} + +impl<FS> VhostUserFsBackend<FS> +where + FS: FileSystem + Send + Sync, +{ + fn process_queue(&mut self, vring: &mut MutexGuard<VringState>) -> std::io::Result<bool> { + let mut used_descs = false; + + while let Some(desc_chain) = vring + .get_queue_mut() + .pop_descriptor_chain(self.guest_mem.memory()) + { + let memory = desc_chain.memory(); + let reader = Reader::from_descriptor_chain(memory, desc_chain.clone()) + .map_err(|_| Error::InvalidDescriptorChain)?; + let writer = VirtioFsWriter::new(memory, desc_chain.clone()) + .map_err(|_| Error::InvalidDescriptorChain)?; + + self.server + .handle_message( + reader, + writer.into(), + self.cache_req + .as_mut() + .map(|req| req as &mut dyn FsCacheReqHandler), + None, + ) + .map_err(Error::HandleRequests)?; + + // TODO: Is len 0 correct? + if let Err(error) = vring + .get_queue_mut() + .add_used(memory, desc_chain.head_index(), 0) + { + error!(?error, "failed to add desc back to ring"); + } + + // TODO: What happens if we error out before here? + used_descs = true; + } + + let needs_notification = if self.event_idx { + match vring + .get_queue_mut() + .needs_notification(self.guest_mem.memory().deref()) + { + Ok(needs_notification) => needs_notification, + Err(error) => { + error!(?error, "failed to check if queue needs notification"); + true + } + } + } else { + true + }; + + if needs_notification { + if let Err(error) = vring.signal_used_queue() { + error!(?error, "failed to signal used queue"); + } + } + + Ok(used_descs) + } +} + +impl<FS> VhostUserBackendMut<VringMutex> for VhostUserFsBackend<FS> +where + FS: FileSystem + Send + Sync, +{ + fn num_queues(&self) -> usize { + NUM_QUEUES + } + + fn max_queue_size(&self) -> usize { + QUEUE_SIZE + } + + fn features(&self) -> u64 { + 1 << VIRTIO_F_VERSION_1 + | 1 << VIRTIO_RING_F_INDIRECT_DESC + | 1 << VIRTIO_RING_F_EVENT_IDX + | VhostUserVirtioFeatures::PROTOCOL_FEATURES.bits() + } + + fn protocol_features(&self) -> VhostUserProtocolFeatures { + VhostUserProtocolFeatures::MQ | VhostUserProtocolFeatures::SLAVE_REQ + } + + fn set_event_idx(&mut self, enabled: bool) { + self.event_idx = enabled; + } + + fn update_memory(&mut self, _mem: GuestMemoryAtomic<GuestMemoryMmap>) -> std::io::Result<()> { + // This is what most the vhost user implementations do... + Ok(()) + } + + fn set_slave_req_fd(&mut self, cache_req: SlaveFsCacheReq) { + self.cache_req = Some(cache_req); + } + + fn handle_event( + &mut self, + device_event: u16, + evset: vmm_sys_util::epoll::EventSet, + vrings: &[VringMutex], + _thread_id: usize, + ) -> std::io::Result<bool> { + if evset != EventSet::IN { + return Err(Error::HandleEventNotEpollIn.into()); + } + + let mut queue = match device_event { + // High priority queue + 0 => vrings[0].get_mut(), + // Regurlar priority queue + 1 => vrings[1].get_mut(), + _ => { + return Err(Error::HandleEventUnknownEvent.into()); + } + }; + + if self.event_idx { + loop { + queue + .get_queue_mut() + .enable_notification(self.guest_mem.memory().deref()) + .map_err(|e| io::Error::new(io::ErrorKind::Other, e.to_string()))?; + if !self.process_queue(&mut queue)? { + break; + } + } + } else { + self.process_queue(&mut queue)?; + } + + Ok(false) + } +} + +pub fn start_virtiofs_daemon<FS, P>(fs: FS, socket: P) -> io::Result<()> +where + FS: FileSystem + Send + Sync + 'static, + P: AsRef<Path>, +{ + let guest_mem = GuestMemoryAtomic::new(GuestMemoryMmap::new()); + + let server = Arc::new(fuse_backend_rs::api::server::Server::new(Arc::new(fs))); + + let backend = Arc::new(RwLock::new(VhostUserFsBackend { + server, + guest_mem: guest_mem.clone(), + event_idx: false, + cache_req: None, + })); + + let listener = Listener::new(socket, true).unwrap(); + + let mut fs_daemon = + VhostUserDaemon::new(String::from("vhost-user-fs-tvix-store"), backend, guest_mem) + .map_err(|_| Error::NewDaemon)?; + + fs_daemon.start(listener).map_err(|_| Error::StartDaemon)?; + + fs_daemon.wait().map_err(|_| Error::WaitDaemon)?; + + Ok(()) +} diff --git a/tvix/castore/src/lib.rs b/tvix/castore/src/lib.rs index 8d3dc7b4c4a5..8da0edef786b 100644 --- a/tvix/castore/src/lib.rs +++ b/tvix/castore/src/lib.rs @@ -4,6 +4,10 @@ mod errors; pub mod blobservice; pub mod directoryservice; pub mod fixtures; + +#[cfg(feature = "fs")] +pub mod fs; + pub mod import; pub mod proto; pub mod tonic; |