36cc7b7088
There's nothing store-path specific here anymore, it's just a name in the mountpoint root. Change-Id: I0f8004491baa03ba560d390053a42678ee81154a Reviewed-on: https://cl.tvl.fyi/c/depot/+/10377 Autosubmit: flokli <flokli@flokli.de> Tested-by: BuildkiteCI Reviewed-by: raitobezarius <tvl@lahfa.xyz>
629 lines
24 KiB
Rust
629 lines
24 KiB
Rust
mod file_attr;
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mod inode_tracker;
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mod inodes;
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mod root_nodes;
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#[cfg(feature = "fuse")]
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pub mod fuse;
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#[cfg(feature = "virtiofs")]
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pub mod virtiofs;
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#[cfg(test)]
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mod tests;
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use fuse_backend_rs::abi::fuse_abi::stat64;
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use fuse_backend_rs::api::filesystem::{Context, FileSystem, FsOptions, ROOT_ID};
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use futures::StreamExt;
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use parking_lot::RwLock;
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use std::ops::Deref;
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use std::{
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collections::HashMap,
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io,
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sync::atomic::AtomicU64,
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sync::{atomic::Ordering, Arc},
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time::Duration,
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};
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use tokio::{
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io::{AsyncReadExt, AsyncSeekExt},
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sync::mpsc,
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};
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use tracing::{debug, info_span, instrument, warn};
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use tvix_castore::proto as castorepb;
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use tvix_castore::{
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blobservice::{BlobReader, BlobService},
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directoryservice::DirectoryService,
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proto::{node::Node, NamedNode},
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B3Digest,
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};
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use self::root_nodes::RootNodes;
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use self::{
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file_attr::{gen_file_attr, ROOT_FILE_ATTR},
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inode_tracker::InodeTracker,
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inodes::{DirectoryInodeData, InodeData},
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};
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/// This implements a read-only FUSE filesystem for a tvix-store
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/// with the passed [BlobService], [DirectoryService] and [RootNodes].
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///
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/// Linux uses inodes in filesystems. When implementing FUSE, most calls are
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/// *for* a given inode.
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///
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/// This means, we need to have a stable mapping of inode numbers to the
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/// corresponding store nodes.
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///
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/// We internally delegate all inode allocation and state keeping to the
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/// inode tracker.
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/// We store a mapping from currently "explored" names in the root to their
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/// inode.
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///
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/// There's some places where inodes are allocated / data inserted into
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/// the inode tracker, if not allocated before already:
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/// - Processing a `lookup` request, either in the mount root, or somewhere
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/// deeper.
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/// - Processing a `readdir` request
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///
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/// Things pointing to the same contents get the same inodes, irrespective of
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/// their own location.
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/// This means:
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/// - Symlinks with the same target will get the same inode.
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/// - Regular/executable files with the same contents will get the same inode
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/// - Directories with the same contents will get the same inode.
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///
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/// Due to the above being valid across the whole store, and considering the
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/// merkle structure is a DAG, not a tree, this also means we can't do "bucketed
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/// allocation", aka reserve Directory.size inodes for each directory node we
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/// explore.
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pub struct TvixStoreFs<BS, DS, RN> {
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blob_service: BS,
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directory_service: DS,
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root_nodes_provider: RN,
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/// Whether to (try) listing elements in the root.
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list_root: bool,
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/// This maps a given basename in the root to the inode we allocated for the node.
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root_nodes: RwLock<HashMap<Vec<u8>, u64>>,
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/// This keeps track of inodes and data alongside them.
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inode_tracker: RwLock<InodeTracker>,
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/// This holds all open file handles
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#[allow(clippy::type_complexity)]
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file_handles: RwLock<HashMap<u64, Arc<tokio::sync::Mutex<Box<dyn BlobReader>>>>>,
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next_file_handle: AtomicU64,
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tokio_handle: tokio::runtime::Handle,
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}
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impl<BS, DS, RN> TvixStoreFs<BS, DS, RN>
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where
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BS: Deref<Target = dyn BlobService> + Clone + Send,
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DS: Deref<Target = dyn DirectoryService> + Clone + Send + 'static,
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RN: RootNodes + Clone + 'static,
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{
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pub fn new(
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blob_service: BS,
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directory_service: DS,
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root_nodes_provider: RN,
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list_root: bool,
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) -> Self {
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Self {
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blob_service,
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directory_service,
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root_nodes_provider,
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list_root,
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root_nodes: RwLock::new(HashMap::default()),
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inode_tracker: RwLock::new(Default::default()),
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file_handles: RwLock::new(Default::default()),
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next_file_handle: AtomicU64::new(1),
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tokio_handle: tokio::runtime::Handle::current(),
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}
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}
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/// Retrieves the inode for a given root node basename, if present.
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/// This obtains a read lock on self.root_nodes.
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fn get_inode_for_root_name(&self, name: &[u8]) -> Option<u64> {
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self.root_nodes.read().get(name).cloned()
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}
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/// For a given inode, look up the given directory behind it (from
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/// self.inode_tracker), and return its children.
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/// The inode_tracker MUST know about this inode already, and it MUST point
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/// to a [InodeData::Directory].
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/// It is ok if it's a [DirectoryInodeData::Sparse] - in that case, a lookup
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/// in self.directory_service is performed, and self.inode_tracker is updated with the
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/// [DirectoryInodeData::Populated].
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#[instrument(skip(self), err)]
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fn get_directory_children(&self, ino: u64) -> io::Result<(B3Digest, Vec<(u64, Node)>)> {
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let data = self.inode_tracker.read().get(ino).unwrap();
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match *data {
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// if it's populated already, return children.
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InodeData::Directory(DirectoryInodeData::Populated(
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ref parent_digest,
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ref children,
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)) => Ok((parent_digest.clone(), children.clone())),
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// if it's sparse, fetch data using directory_service, populate child nodes
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// and update it in [self.inode_tracker].
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InodeData::Directory(DirectoryInodeData::Sparse(ref parent_digest, _)) => {
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let directory = self
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.tokio_handle
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.block_on(self.tokio_handle.spawn({
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let directory_service = self.directory_service.clone();
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let parent_digest = parent_digest.to_owned();
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async move { directory_service.get(&parent_digest).await }
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}))
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.unwrap()?
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.ok_or_else(|| {
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warn!(directory.digest=%parent_digest, "directory not found");
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// If the Directory can't be found, this is a hole, bail out.
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io::Error::from_raw_os_error(libc::EIO)
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})?;
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// Turn the retrieved directory into a InodeData::Directory(DirectoryInodeData::Populated(..)),
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// allocating inodes for the children on the way.
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let children = {
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let mut inode_tracker = self.inode_tracker.write();
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let children: Vec<(u64, castorepb::node::Node)> = directory
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.nodes()
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.map(|child_node| {
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let child_ino = inode_tracker.put((&child_node).into());
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(child_ino, child_node)
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})
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.collect();
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// replace.
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inode_tracker.replace(
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ino,
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Arc::new(InodeData::Directory(DirectoryInodeData::Populated(
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parent_digest.clone(),
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children.clone(),
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))),
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);
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children
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};
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Ok((parent_digest.clone(), children))
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}
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// if the parent inode was not a directory, this doesn't make sense
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InodeData::Regular(..) | InodeData::Symlink(_) => {
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Err(io::Error::from_raw_os_error(libc::ENOTDIR))
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}
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}
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}
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/// This will turn a lookup request for a name in the root to a ino and
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/// [InodeData].
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/// It will peek in [self.root_nodes], and then either look it up from
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/// [self.inode_tracker],
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/// or otherwise fetch from [self.root_nodes], and then insert into
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/// [self.inode_tracker].
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/// In the case the name can't be found, a libc::ENOENT is returned.
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fn name_in_root_to_ino_and_data(
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&self,
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name: &std::ffi::CStr,
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) -> io::Result<(u64, Arc<InodeData>)> {
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// Look up the inode for that root node.
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// If there's one, [self.inode_tracker] MUST also contain the data,
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// which we can then return.
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if let Some(inode) = self.get_inode_for_root_name(name.to_bytes()) {
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return Ok((
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inode,
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self.inode_tracker
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.read()
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.get(inode)
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.expect("must exist")
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.to_owned(),
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));
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}
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// We don't have it yet, look it up in [self.root_nodes].
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match self.tokio_handle.block_on({
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let root_nodes_provider = self.root_nodes_provider.clone();
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async move { root_nodes_provider.get_by_basename(name.to_bytes()).await }
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}) {
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// if there was an error looking up the root node, propagate up an IO error.
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Err(_e) => Err(io::Error::from_raw_os_error(libc::EIO)),
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// the root node doesn't exist, so the file doesn't exist.
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Ok(None) => Err(io::Error::from_raw_os_error(libc::ENOENT)),
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// The root node does exist
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Ok(Some(root_node)) => {
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// The name must match what's passed in the lookup, otherwise this is also a ENOENT.
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if root_node.get_name() != name.to_bytes() {
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debug!(root_node.name=?root_node.get_name(), found_node.name=%name.to_string_lossy(), "node name mismatch");
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return Err(io::Error::from_raw_os_error(libc::ENOENT));
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}
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// Let's check if someone else beat us to updating the inode tracker and
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// root_nodes map. This avoids locking inode_tracker for writing.
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if let Some(ino) = self.root_nodes.read().get(name.to_bytes()) {
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return Ok((
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*ino,
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self.inode_tracker.read().get(*ino).expect("must exist"),
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));
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}
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// Only in case it doesn't, lock [self.root_nodes] and
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// [self.inode_tracker] for writing.
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let mut root_nodes = self.root_nodes.write();
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let mut inode_tracker = self.inode_tracker.write();
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// insert the (sparse) inode data and register in
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// self.root_nodes.
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let inode_data: InodeData = (&root_node).into();
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let ino = inode_tracker.put(inode_data.clone());
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root_nodes.insert(name.to_bytes().into(), ino);
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Ok((ino, Arc::new(inode_data)))
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}
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}
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}
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}
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impl<BS, DS, RN> FileSystem for TvixStoreFs<BS, DS, RN>
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where
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BS: Deref<Target = dyn BlobService> + Clone + Send + 'static,
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DS: Deref<Target = dyn DirectoryService> + Send + Clone + 'static,
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RN: RootNodes + Clone + 'static,
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{
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type Handle = u64;
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type Inode = u64;
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fn init(&self, _capable: FsOptions) -> io::Result<FsOptions> {
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Ok(FsOptions::empty())
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}
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#[tracing::instrument(skip_all, fields(rq.inode = inode))]
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fn getattr(
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&self,
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_ctx: &Context,
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inode: Self::Inode,
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_handle: Option<Self::Handle>,
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) -> io::Result<(stat64, Duration)> {
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if inode == ROOT_ID {
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return Ok((ROOT_FILE_ATTR.into(), Duration::MAX));
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}
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match self.inode_tracker.read().get(inode) {
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None => Err(io::Error::from_raw_os_error(libc::ENOENT)),
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Some(node) => {
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debug!(node = ?node, "found node");
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Ok((gen_file_attr(&node, inode).into(), Duration::MAX))
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}
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}
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}
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#[tracing::instrument(skip_all, fields(rq.parent_inode = parent, rq.name = ?name))]
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fn lookup(
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&self,
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_ctx: &Context,
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parent: Self::Inode,
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name: &std::ffi::CStr,
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) -> io::Result<fuse_backend_rs::api::filesystem::Entry> {
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debug!("lookup");
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// This goes from a parent inode to a node.
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// - If the parent is [ROOT_ID], we need to check
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// [self.root_nodes] (fetching from a [RootNode] provider if needed)
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// - Otherwise, lookup the parent in [self.inode_tracker] (which must be
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// a [InodeData::Directory]), and find the child with that name.
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if parent == ROOT_ID {
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let (ino, inode_data) = self.name_in_root_to_ino_and_data(name)?;
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debug!(inode_data=?&inode_data, ino=ino, "Some");
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return Ok(fuse_backend_rs::api::filesystem::Entry {
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inode: ino,
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attr: gen_file_attr(&inode_data, ino).into(),
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attr_timeout: Duration::MAX,
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entry_timeout: Duration::MAX,
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..Default::default()
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});
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}
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// This is the "lookup for "a" inside inode 42.
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// We already know that inode 42 must be a directory.
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let (parent_digest, children) = self.get_directory_children(parent)?;
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let span = info_span!("lookup", directory.digest = %parent_digest);
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let _enter = span.enter();
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// Search for that name in the list of children and return the FileAttrs.
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// in the children, find the one with the desired name.
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if let Some((child_ino, _)) = children.iter().find(|e| e.1.get_name() == name.to_bytes()) {
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// lookup the child [InodeData] in [self.inode_tracker].
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// We know the inodes for children have already been allocated.
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let child_inode_data = self.inode_tracker.read().get(*child_ino).unwrap();
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// Reply with the file attributes for the child.
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// For child directories, we still have all data we need to reply.
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Ok(fuse_backend_rs::api::filesystem::Entry {
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inode: *child_ino,
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attr: gen_file_attr(&child_inode_data, *child_ino).into(),
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attr_timeout: Duration::MAX,
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entry_timeout: Duration::MAX,
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..Default::default()
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})
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} else {
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// Child not found, return ENOENT.
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Err(io::Error::from_raw_os_error(libc::ENOENT))
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}
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}
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// TODO: readdirplus?
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#[tracing::instrument(skip_all, fields(rq.inode = inode, rq.offset = offset))]
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fn readdir(
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&self,
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_ctx: &Context,
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inode: Self::Inode,
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_handle: Self::Handle,
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_size: u32,
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offset: u64,
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add_entry: &mut dyn FnMut(fuse_backend_rs::api::filesystem::DirEntry) -> io::Result<usize>,
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) -> io::Result<()> {
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debug!("readdir");
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if inode == ROOT_ID {
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if !self.list_root {
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return Err(io::Error::from_raw_os_error(libc::EPERM)); // same error code as ipfs/kubo
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} else {
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let root_nodes_provider = self.root_nodes_provider.clone();
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let (tx, mut rx) = mpsc::channel(16);
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// This task will run in the background immediately and will exit
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// after the stream ends or if we no longer want any more entries.
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self.tokio_handle.spawn(async move {
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let mut stream = root_nodes_provider.list().skip(offset as usize).enumerate();
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while let Some(node) = stream.next().await {
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if tx.send(node).await.is_err() {
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// If we get a send error, it means the sync code
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// doesn't want any more entries.
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break;
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}
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}
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});
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while let Some((i, root_node)) = rx.blocking_recv() {
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let root_node = match root_node {
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Err(e) => {
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warn!("failed to retrieve pathinfo: {}", e);
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return Err(io::Error::from_raw_os_error(libc::EPERM));
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}
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Ok(root_node) => root_node,
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};
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let name = root_node.get_name();
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// obtain the inode, or allocate a new one.
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let ino = self.get_inode_for_root_name(name).unwrap_or_else(|| {
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// insert the (sparse) inode data and register in
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// self.root_nodes.
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let ino = self.inode_tracker.write().put((&root_node).into());
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self.root_nodes.write().insert(name.into(), ino);
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ino
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});
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let ty = match root_node {
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Node::Directory(_) => libc::S_IFDIR,
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Node::File(_) => libc::S_IFREG,
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Node::Symlink(_) => libc::S_IFLNK,
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};
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let written = add_entry(fuse_backend_rs::api::filesystem::DirEntry {
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ino,
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offset: offset + i as u64 + 1,
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type_: ty,
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name,
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})?;
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// If the buffer is full, add_entry will return `Ok(0)`.
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if written == 0 {
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break;
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}
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}
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return Ok(());
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}
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}
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|
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// lookup the children, or return an error if it's not a directory.
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let (parent_digest, children) = self.get_directory_children(inode)?;
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let span = info_span!("lookup", directory.digest = %parent_digest);
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let _enter = span.enter();
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for (i, (ino, child_node)) in children.iter().skip(offset as usize).enumerate() {
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// the second parameter will become the "offset" parameter on the next call.
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let written = add_entry(fuse_backend_rs::api::filesystem::DirEntry {
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ino: *ino,
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offset: offset + i as u64 + 1,
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type_: match child_node {
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#[allow(clippy::unnecessary_cast)]
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// libc::S_IFDIR is u32 on Linux and u16 on MacOS
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Node::Directory(_) => libc::S_IFDIR as u32,
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#[allow(clippy::unnecessary_cast)]
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// libc::S_IFDIR is u32 on Linux and u16 on MacOS
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Node::File(_) => libc::S_IFREG as u32,
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#[allow(clippy::unnecessary_cast)]
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// libc::S_IFDIR is u32 on Linux and u16 on MacOS
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Node::Symlink(_) => libc::S_IFLNK as u32,
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},
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name: child_node.get_name(),
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})?;
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// If the buffer is full, add_entry will return `Ok(0)`.
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|
if written == 0 {
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break;
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}
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}
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Ok(())
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}
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|
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#[tracing::instrument(skip_all, fields(rq.inode = inode))]
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|
fn open(
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&self,
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_ctx: &Context,
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inode: Self::Inode,
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_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()),
|
|
}
|
|
}
|
|
}
|