proxmox-backup/src/backup/chunk_store.rs

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Rust
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use failure::*;
use std::path::{Path, PathBuf};
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use std::io::Write;
use crypto::digest::Digest;
use crypto::sha2::Sha512Trunc256;
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use std::sync::Mutex;
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use std::fs::File;
use std::os::unix::io::AsRawFd;
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use crate::tools;
pub struct ChunkStore {
base: PathBuf,
chunk_dir: PathBuf,
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hasher: Sha512Trunc256,
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mutex: Mutex<bool>,
lockfile: File,
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}
const HEX_CHARS: &'static [u8; 16] = b"0123456789abcdef";
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pub fn digest_to_hex(digest: &[u8]) -> String {
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let mut buf = Vec::<u8>::with_capacity(digest.len()*2);
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for i in 0..digest.len() {
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buf.push(HEX_CHARS[(digest[i] >> 4) as usize]);
buf.push(HEX_CHARS[(digest[i] & 0xf) as usize]);
}
unsafe { String::from_utf8_unchecked(buf) }
}
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fn digest_to_prefix(digest: &[u8]) -> PathBuf {
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let mut buf = Vec::<u8>::with_capacity(3+1+2+1);
buf.push(HEX_CHARS[(digest[0] as usize) >> 4]);
buf.push(HEX_CHARS[(digest[0] as usize) &0xf]);
buf.push(HEX_CHARS[(digest[1] as usize) >> 4]);
buf.push('/' as u8);
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buf.push(HEX_CHARS[(digest[1] as usize) & 0xf]);
buf.push(HEX_CHARS[(digest[2] as usize) >> 4]);
buf.push('/' as u8);
let path = unsafe { String::from_utf8_unchecked(buf)};
path.into()
}
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impl ChunkStore {
fn chunk_dir<P: AsRef<Path>>(path: P) -> PathBuf {
let mut chunk_dir: PathBuf = PathBuf::from(path.as_ref());
chunk_dir.push(".chunks");
chunk_dir
}
pub fn create<P: Into<PathBuf>>(path: P) -> Result<Self, Error> {
let base: PathBuf = path.into();
let chunk_dir = Self::chunk_dir(&base);
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if let Err(err) = std::fs::create_dir(&base) {
bail!("unable to create chunk store {:?} - {}", base, err);
}
if let Err(err) = std::fs::create_dir(&chunk_dir) {
bail!("unable to create chunk store subdir {:?} - {}", chunk_dir, err);
}
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// create 4096 subdir
for i in 0..4096 {
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let mut l1path = chunk_dir.clone();
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l1path.push(format!("{:03x}",i));
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if let Err(err) = std::fs::create_dir(&l1path) {
bail!("unable to create chunk subdir {:?} - {}", l1path, err);
}
}
Self::open(base)
}
pub fn open<P: Into<PathBuf>>(path: P) -> Result<Self, Error> {
let base: PathBuf = path.into();
let chunk_dir = Self::chunk_dir(&base);
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if let Err(err) = std::fs::metadata(&chunk_dir) {
bail!("unable to open chunk store {:?} - {}", chunk_dir, err);
}
let mut lockfile_path = base.clone();
lockfile_path.push(".lock");
// make sure only one process/thread/task can use it
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let lockfile = tools::lock_file(lockfile_path, 10)?;
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Ok(ChunkStore {
base,
chunk_dir,
hasher: Sha512Trunc256::new(),
lockfile,
mutex: Mutex::new(false)
})
}
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pub fn touch_chunk(&mut self, digest:&[u8]) -> Result<(), Error> {
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// fixme: nix::sys::stat::utimensat
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let mut chunk_path = self.chunk_dir.clone();
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let prefix = digest_to_prefix(&digest);
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chunk_path.push(&prefix);
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let digest_str = digest_to_hex(&digest);
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chunk_path.push(&digest_str);
std::fs::metadata(&chunk_path)?;
Ok(())
}
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fn sweep_old_files(&self, dir: &Path) {
let mut handle = match nix::dir::Dir::open(
dir, nix::fcntl::OFlag::O_RDONLY, nix::sys::stat::Mode::empty()) {
Ok(h) => h,
Err(_) => return,
};
let rawfd = handle.as_raw_fd();
let now = unsafe { libc::time(std::ptr::null_mut()) };
for entry in handle.iter() {
match entry {
Ok(entry) => {
if let Some(file_type) = entry.file_type() {
if file_type == nix::dir::Type::File {
let filename = entry.file_name();
if let Ok(stat) = nix::sys::stat::fstatat(rawfd, filename, nix::fcntl::AtFlags::AT_SYMLINK_NOFOLLOW) {
let age = now - stat.st_atime;
println!("FOUND {} {:?}", age/(3600*24), filename);
if age/(3600*24) >= 2 {
println!("UNLINK {} {:?}", age/(3600*24), filename);
unsafe { libc::unlinkat(rawfd, filename.as_ptr(), 0); }
}
}
}
}
}
Err(_) => {
// fixme ??
}
}
}
}
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pub fn sweep_used_chunks(&mut self) -> Result<(), Error> {
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for i in 0..4096 {
let mut l1path = self.chunk_dir.clone();
l1path.push(format!("{:03x}", i));
for j in 0..256 {
let mut l2path = l1path.clone();
l2path.push(format!("{:02x}", j));
self.sweep_old_files(&l2path);
}
}
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Ok(())
}
pub fn insert_chunk(&mut self, chunk: &[u8]) -> Result<(bool, [u8; 32]), Error> {
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self.hasher.reset();
self.hasher.input(chunk);
let mut digest = [0u8; 32];
self.hasher.result(&mut digest);
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//println!("DIGEST {}", digest_to_hex(&digest));
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let mut chunk_path = self.chunk_dir.clone();
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let prefix = digest_to_prefix(&digest);
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chunk_path.push(&prefix);
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let digest_str = digest_to_hex(&digest);
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chunk_path.push(&digest_str);
let lock = self.mutex.lock();
if let Ok(metadata) = std::fs::metadata(&chunk_path) {
if metadata.is_file() {
return Ok((true, digest));
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} else {
bail!("Got unexpected file type for chunk {}", digest_str);
}
}
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let mut chunk_dir = self.chunk_dir.clone();
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chunk_dir.push(&prefix);
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if let Err(_) = std::fs::create_dir(&chunk_dir) { /* ignore */ }
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let mut tmp_path = chunk_path.clone();
tmp_path.set_extension("tmp");
let mut f = std::fs::File::create(&tmp_path)?;
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f.write_all(chunk)?;
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if let Err(err) = std::fs::rename(&tmp_path, &chunk_path) {
if let Err(_) = std::fs::remove_file(&tmp_path) { /* ignore */ }
bail!("Atomic rename failed for chunk {} - {}", digest_str, err);
}
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println!("PATH {:?}", chunk_path);
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drop(lock);
Ok((false, digest))
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}
pub fn relative_path(&self, path: &Path) -> PathBuf {
let mut full_path = self.base.clone();
full_path.push(path);
full_path
}
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pub fn base_path(&self) -> PathBuf {
self.base.clone()
}
}
#[test]
fn test_chunk_store1() {
if let Err(_e) = std::fs::remove_dir_all(".testdir") { /* ignore */ }
let chunk_store = ChunkStore::open(".testdir");
assert!(chunk_store.is_err());
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let mut chunk_store = ChunkStore::create(".testdir").unwrap();
let (exists, _) = chunk_store.insert_chunk(&[0u8, 1u8]).unwrap();
assert!(!exists);
let (exists, _) = chunk_store.insert_chunk(&[0u8, 1u8]).unwrap();
assert!(exists);
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let chunk_store = ChunkStore::create(".testdir");
assert!(chunk_store.is_err());
}