storage_benchmarks/
filesystem.rs

1// Copyright 2022 The Fuchsia Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5use crate::BlockDeviceFactory;
6use async_trait::async_trait;
7use std::future::Future;
8use std::path::{Path, PathBuf};
9use std::pin::Pin;
10
11/// A trait for creating `Filesystem`s.
12#[async_trait]
13pub trait FilesystemConfig: Send + Sync {
14    /// The concrete type of the filesystem started by `start_filesystem`. It must at least
15    /// implement the `Filesystem` trait.
16    type Filesystem: Filesystem;
17
18    /// Starts an instance of the filesystem.
19    async fn start_filesystem(
20        &self,
21        block_device_factory: &dyn BlockDeviceFactory,
22    ) -> Self::Filesystem;
23
24    /// The name of the filesystem. This is used for filtering benchmarks and outputting results.
25    fn name(&self) -> String;
26}
27
28/// A trait representing a mounted filesystem that benchmarks will be run against.
29#[async_trait]
30pub trait Filesystem: Send + Sync + BoxedFilesystem {
31    /// Cleans up the filesystem after a benchmark has run. Filesystem is unusable after this call.
32    async fn shutdown(self);
33
34    /// Path to where the filesystem is located in the current process's namespace. All benchmark
35    /// operations should happen within this directory.
36    fn benchmark_dir(&self) -> &Path;
37}
38
39/// Helper trait for shutting down `Box<dyn Filesystem>` objects.
40pub trait BoxedFilesystem: Send + Sync {
41    /// `Filesystem::shutdown` takes the filesystem by value which doesn't work for `Box<&dyn
42    /// Filesystem>` because the filesystem type isn't known at compile time. Taking the filesystem
43    /// as `Box<Self>` works and the type of the filesystem is now known so the
44    /// `Filesystem::shutdown` method can be called.
45    fn shutdown_boxed<'a>(self: Box<Self>) -> Pin<Box<dyn Future<Output = ()> + Send + 'a>>
46    where
47        Self: 'a;
48}
49
50impl<T: Filesystem> BoxedFilesystem for T {
51    fn shutdown_boxed<'a>(self: Box<Self>) -> Pin<Box<dyn Future<Output = ()> + Send + 'a>>
52    where
53        Self: 'a,
54    {
55        (*self).shutdown()
56    }
57}
58
59/// A trait for filesystems that are able to clear their caches.
60#[async_trait]
61pub trait CacheClearableFilesystem: Filesystem {
62    /// Clears all cached data in the filesystem. This method is used in "cold" benchmarks to
63    /// ensure that the filesystem isn't using cached data from the setup phase in the benchmark
64    /// phase.
65    async fn clear_cache(&mut self);
66}
67
68/// A `FilesystemConfig` for a filesystem that is already present in the process's namespace.
69#[derive(Clone)]
70pub struct MountedFilesystem {
71    /// Path to an existing filesystem.
72    dir: PathBuf,
73
74    /// Name of the filesystem that backs `dir`.
75    name: String,
76}
77
78impl MountedFilesystem {
79    pub fn new<P: Into<PathBuf>>(dir: P, name: String) -> Self {
80        Self { dir: dir.into(), name }
81    }
82}
83
84#[async_trait]
85impl FilesystemConfig for MountedFilesystem {
86    type Filesystem = MountedFilesystemInstance;
87    async fn start_filesystem(
88        &self,
89        _block_device_factory: &dyn BlockDeviceFactory,
90    ) -> MountedFilesystemInstance {
91        // Create a new directory within the existing filesystem to make it easier for cleaning up
92        // afterwards.
93        let path = self.dir.join("benchmark");
94        std::fs::create_dir(&path).unwrap_or_else(|e| {
95            panic!("failed to created benchmark directory '{}': {:?}", path.display(), e)
96        });
97        MountedFilesystemInstance::new(path)
98    }
99
100    fn name(&self) -> String {
101        self.name.clone()
102    }
103}
104
105/// A `Filesystem` instance for a filesystem that is already present in the process's namespace.
106pub struct MountedFilesystemInstance {
107    dir: PathBuf,
108}
109
110impl MountedFilesystemInstance {
111    pub fn new<P: Into<PathBuf>>(dir: P) -> Self {
112        Self { dir: dir.into() }
113    }
114}
115
116#[async_trait]
117impl Filesystem for MountedFilesystemInstance {
118    async fn shutdown(self) {
119        std::fs::remove_dir_all(self.dir).expect("Failed to remove benchmark directory");
120    }
121
122    fn benchmark_dir(&self) -> &Path {
123        self.dir.as_path()
124    }
125}
storage_benchmarks/filesystem.rs

storage_benchmarks/
filesystem.rs
