proxmox-backup/src/backup/chunk_store.rs

350 lines
10 KiB
Rust

use failure::*;
use std::path::{Path, PathBuf};
use std::io::Write;
use std::time::Duration;
use openssl::sha;
use std::sync::Mutex;
use std::fs::File;
use std::os::unix::io::AsRawFd;
use crate::tools;
pub struct GarbageCollectionStatus {
pub used_bytes: usize,
pub used_chunks: usize,
pub disk_bytes: usize,
pub disk_chunks: usize,
}
impl Default for GarbageCollectionStatus {
fn default() -> Self {
GarbageCollectionStatus {
used_bytes: 0,
used_chunks: 0,
disk_bytes: 0,
disk_chunks: 0,
}
}
}
pub struct ChunkStore {
name: String, // used for error reporting
pub (crate) base: PathBuf,
chunk_dir: PathBuf,
mutex: Mutex<bool>,
_lockfile: File,
}
// TODO: what about sysctl setting vm.vfs_cache_pressure (0 - 100) ?
fn digest_to_prefix(digest: &[u8]) -> PathBuf {
let mut buf = Vec::<u8>::with_capacity(2+1+2+1);
const HEX_CHARS: &'static [u8; 16] = b"0123456789abcdef";
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(HEX_CHARS[(digest[1] as usize) & 0xf]);
buf.push('/' as u8);
let path = unsafe { String::from_utf8_unchecked(buf)};
path.into()
}
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>>(name: &str, path: P) -> Result<Self, Error> {
let base: PathBuf = path.into();
if !base.is_absolute() {
bail!("expected absolute path - got {:?}", base);
}
let chunk_dir = Self::chunk_dir(&base);
if let Err(err) = std::fs::create_dir(&base) {
bail!("unable to create chunk store '{}' at {:?} - {}", name, base, err);
}
if let Err(err) = std::fs::create_dir(&chunk_dir) {
bail!("unable to create chunk store '{}' subdir {:?} - {}", name, chunk_dir, err);
}
// create 64*1024 subdirs
let mut last_percentage = 0;
for i in 0..64*1024 {
let mut l1path = chunk_dir.clone();
l1path.push(format!("{:04x}", i));
if let Err(err) = std::fs::create_dir(&l1path) {
bail!("unable to create chunk store '{}' subdir {:?} - {}", name, l1path, err);
}
let percentage = (i*100)/(64*1024);
if percentage != last_percentage {
eprintln!("Percentage done: {}", percentage);
last_percentage = percentage;
}
}
Self::open(name, base)
}
pub fn open<P: Into<PathBuf>>(name: &str, path: P) -> Result<Self, Error> {
let base: PathBuf = path.into();
if !base.is_absolute() {
bail!("expected absolute path - got {:?}", base);
}
let chunk_dir = Self::chunk_dir(&base);
if let Err(err) = std::fs::metadata(&chunk_dir) {
bail!("unable to open chunk store '{}' at {:?} - {}", name, chunk_dir, err);
}
let mut lockfile_path = base.clone();
lockfile_path.push(".lock");
// make sure only one process/thread/task can use it
let lockfile = tools::open_file_locked(
lockfile_path, Duration::from_secs(10))?;
Ok(ChunkStore {
name: name.to_owned(),
base,
chunk_dir,
_lockfile: lockfile,
mutex: Mutex::new(false)
})
}
pub fn touch_chunk(&self, digest:&[u8]) -> Result<(), Error> {
let mut chunk_path = self.chunk_dir.clone();
let prefix = digest_to_prefix(&digest);
chunk_path.push(&prefix);
let digest_str = tools::digest_to_hex(&digest);
chunk_path.push(&digest_str);
const UTIME_NOW: i64 = ((1 << 30) - 1);
const UTIME_OMIT: i64 = ((1 << 30) - 2);
let times: [libc::timespec; 2] = [
libc::timespec { tv_sec: 0, tv_nsec: UTIME_NOW },
libc::timespec { tv_sec: 0, tv_nsec: UTIME_OMIT }
];
use nix::NixPath;
let res = chunk_path.with_nix_path(|cstr| unsafe {
libc::utimensat(-1, cstr.as_ptr(), &times[0], libc::AT_SYMLINK_NOFOLLOW)
})?;
if let Err(err) = nix::errno::Errno::result(res) {
bail!("updata atime failed for chunk {:?} - {}", chunk_path, err);
}
Ok(())
}
pub fn read_chunk(&self, digest:&[u8], buffer: &mut Vec<u8>) -> Result<(), Error> {
let mut chunk_path = self.chunk_dir.clone();
let prefix = digest_to_prefix(&digest);
chunk_path.push(&prefix);
let digest_str = tools::digest_to_hex(&digest);
chunk_path.push(&digest_str);
let mut f = std::fs::File::open(&chunk_path)?;
let stat = nix::sys::stat::fstat(f.as_raw_fd())?;
let size = stat.st_size as usize;
if buffer.capacity() < size {
let mut newsize = buffer.capacity();
while newsize < size { newsize = newsize << 1; }
let additional = newsize - buffer.len();
buffer.reserve_exact(additional);
}
unsafe { buffer.set_len(size); }
use std::io::Read;
f.read_exact(buffer.as_mut_slice())?;
Ok(())
}
fn sweep_old_files(&self, handle: &mut nix::dir::Dir, status: &mut GarbageCollectionStatus) -> Result<(), Error> {
let rawfd = handle.as_raw_fd();
let now = unsafe { libc::time(std::ptr::null_mut()) };
for entry in handle.iter() {
let entry = match entry {
Ok(entry) => entry,
Err(_) => continue /* ignore */,
};
let file_type = match entry.file_type() {
Some(file_type) => file_type,
None => bail!("unsupported file system type on chunk store '{}'", self.name),
};
if file_type != nix::dir::Type::File { continue; }
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);
let res = unsafe { libc::unlinkat(rawfd, filename.as_ptr(), 0) };
if res != 0 {
let err = nix::Error::last();
bail!("unlink chunk {:?} failed on store '{}' - {}", filename, self.name, err);
}
} else {
status.disk_chunks += 1;
status.disk_bytes += stat.st_size as usize;
}
}
}
Ok(())
}
pub fn sweep_unused_chunks(&self, status: &mut GarbageCollectionStatus) -> Result<(), Error> {
use nix::fcntl::OFlag;
use nix::sys::stat::Mode;
use nix::dir::Dir;
let base_handle = match Dir::open(
&self.chunk_dir, OFlag::O_RDONLY, Mode::empty()) {
Ok(h) => h,
Err(err) => bail!("unable to open store '{}' chunk dir {:?} - {}",
self.name, self.chunk_dir, err),
};
let base_fd = base_handle.as_raw_fd();
let mut last_percentage = 0;
for i in 0..64*1024 {
let percentage = (i*100)/(64*1024);
if percentage != last_percentage {
eprintln!("Percentage done: {}", percentage);
last_percentage = percentage;
}
let l1name = PathBuf::from(format!("{:04x}", i));
match nix::dir::Dir::openat(base_fd, &l1name, OFlag::O_RDONLY, Mode::empty()) {
Ok(mut h) => {
//println!("SCAN {:?} {:?}", l1name);
self.sweep_old_files(&mut h, status)?;
}
Err(err) => bail!("unable to open store '{}' dir {:?}/{:?} - {}",
self.name, self.chunk_dir, l1name, err),
};
}
Ok(())
}
pub fn insert_chunk(&self, chunk: &[u8]) -> Result<(bool, [u8; 32]), Error> {
// fixme: use Sha512/256 when available
let mut hasher = sha::Sha256::new();
hasher.update(chunk);
let digest = hasher.finish();
//println!("DIGEST {}", tools::digest_to_hex(&digest));
let mut chunk_path = self.chunk_dir.clone();
let prefix = digest_to_prefix(&digest);
chunk_path.push(&prefix);
let digest_str = tools::digest_to_hex(&digest);
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));
} else {
bail!("Got unexpected file type on store '{}' for chunk {}", self.name, digest_str);
}
}
let mut tmp_path = chunk_path.clone();
tmp_path.set_extension("tmp");
let mut f = std::fs::File::create(&tmp_path)?;
f.write_all(chunk)?;
if let Err(err) = std::fs::rename(&tmp_path, &chunk_path) {
if let Err(_) = std::fs::remove_file(&tmp_path) { /* ignore */ }
bail!("Atomic rename on store '{}' failed for chunk {} - {}", self.name, digest_str, err);
}
//println!("PATH {:?}", chunk_path);
drop(lock);
Ok((false, digest))
}
pub fn relative_path(&self, path: &Path) -> PathBuf {
let mut full_path = self.base.clone();
full_path.push(path);
full_path
}
pub fn base_path(&self) -> PathBuf {
self.base.clone()
}
}
#[test]
fn test_chunk_store1() {
let mut path = std::fs::canonicalize(".").unwrap(); // we need absulute path
path.push(".testdir");
if let Err(_e) = std::fs::remove_dir_all(".testdir") { /* ignore */ }
let chunk_store = ChunkStore::open("test", &path);
assert!(chunk_store.is_err());
let chunk_store = ChunkStore::create("test", &path).unwrap();
let (exists, _) = chunk_store.insert_chunk(&[0u8, 1u8]).unwrap();
assert!(!exists);
let (exists, _) = chunk_store.insert_chunk(&[0u8, 1u8]).unwrap();
assert!(exists);
let chunk_store = ChunkStore::create("test", &path);
assert!(chunk_store.is_err());
if let Err(_e) = std::fs::remove_dir_all(".testdir") { /* ignore */ }
}