src/backup/chunk_store.rs

   1 use anyhow::{bail, format_err, Error};
   2
   3 use std::path::{Path, PathBuf};
   4 use std::io::Write;
   5 use std::sync::{Arc, Mutex};
   6 use std::os::unix::io::AsRawFd;
   7
   8 use proxmox::tools::fs::{CreateOptions, create_path, create_dir};
   9
  10 use crate::tools;
  11 use crate::api2::types::GarbageCollectionStatus;
  12
  13 use super::DataBlob;
  14 use crate::server::WorkerTask;
  15
  16 /// File system based chunk store
  17 pub struct ChunkStore {
  18     name: String, // used for error reporting
  19     pub (crate) base: PathBuf,
  20     chunk_dir: PathBuf,
  21     mutex: Mutex<bool>,
  22     locker: Arc<Mutex<tools::ProcessLocker>>,
  23 }
  24
  25 // TODO: what about sysctl setting vm.vfs_cache_pressure (0 - 100) ?
  26
  27 pub fn verify_chunk_size(size: usize) -> Result<(), Error> {
  28
  29     static SIZES: [usize; 7] = [64*1024, 128*1024, 256*1024, 512*1024, 1024*1024, 2048*1024, 4096*1024];
  30
  31     if !SIZES.contains(&size) {
  32         bail!("Got unsupported chunk size '{}'", size);
  33     }
  34     Ok(())
  35 }
  36
  37 fn digest_to_prefix(digest: &[u8]) -> PathBuf {
  38
  39     let mut buf = Vec::<u8>::with_capacity(2+1+2+1);
  40
  41     const HEX_CHARS: &[u8; 16] = b"0123456789abcdef";
  42
  43     buf.push(HEX_CHARS[(digest[0] as usize) >> 4]);
  44     buf.push(HEX_CHARS[(digest[0] as usize) &0xf]);
  45     buf.push(HEX_CHARS[(digest[1] as usize) >> 4]);
  46     buf.push(HEX_CHARS[(digest[1] as usize) & 0xf]);
  47     buf.push('/' as u8);
  48
  49     let path = unsafe { String::from_utf8_unchecked(buf)};
  50
  51     path.into()
  52 }
  53
  54 impl ChunkStore {
  55
  56     fn chunk_dir<P: AsRef<Path>>(path: P) -> PathBuf {
  57
  58         let mut chunk_dir: PathBuf = PathBuf::from(path.as_ref());
  59         chunk_dir.push(".chunks");
  60
  61         chunk_dir
  62     }
  63
  64     pub fn create<P>(name: &str, path: P, uid: nix::unistd::Uid, gid: nix::unistd::Gid) -> Result<Self, Error>
  65     where
  66         P: Into<PathBuf>,
  67     {
  68
  69         let base: PathBuf = path.into();
  70
  71         if !base.is_absolute() {
  72             bail!("expected absolute path - got {:?}", base);
  73         }
  74
  75         let chunk_dir = Self::chunk_dir(&base);
  76
  77         let options = CreateOptions::new()
  78             .owner(uid)
  79             .group(gid);
  80
  81         let default_options = CreateOptions::new();
  82
  83         if let Err(err) = create_path(&base, Some(default_options.clone()), Some(options.clone())) {
  84             bail!("unable to create chunk store '{}' at {:?} - {}", name, base, err);
  85         }
  86
  87         if let Err(err) = create_dir(&chunk_dir, options.clone()) {
  88             bail!("unable to create chunk store '{}' subdir {:?} - {}", name, chunk_dir, err);
  89         }
  90
  91         // create lock file with correct owner/group
  92         let lockfile_path = Self::lockfile_path(&base);
  93         proxmox::tools::fs::replace_file(lockfile_path, b"", options.clone())?;
  94
  95         // create 64*1024 subdirs
  96         let mut last_percentage = 0;
  97
  98         for i in 0..64*1024 {
  99             let mut l1path = chunk_dir.clone();
 100             l1path.push(format!("{:04x}", i));
 101             if let Err(err) = create_dir(&l1path, options.clone()) {
 102                 bail!("unable to create chunk store '{}' subdir {:?} - {}", name, l1path, err);
 103             }
 104             let percentage = (i*100)/(64*1024);
 105             if percentage != last_percentage {
 106                 eprintln!("Percentage done: {}", percentage);
 107                 last_percentage = percentage;
 108             }
 109         }
 110
 111
 112         Self::open(name, base)
 113     }
 114
 115     fn lockfile_path<P: Into<PathBuf>>(base: P) -> PathBuf {
 116         let base: PathBuf = base.into();
 117
 118         let mut lockfile_path = base.clone();
 119         lockfile_path.push(".lock");
 120
 121         lockfile_path
 122     }
 123
 124     pub fn open<P: Into<PathBuf>>(name: &str, base: P) -> Result<Self, Error> {
 125
 126         let base: PathBuf = base.into();
 127
 128         if !base.is_absolute() {
 129             bail!("expected absolute path - got {:?}", base);
 130         }
 131
 132         let chunk_dir = Self::chunk_dir(&base);
 133
 134         if let Err(err) = std::fs::metadata(&chunk_dir) {
 135             bail!("unable to open chunk store '{}' at {:?} - {}", name, chunk_dir, err);
 136         }
 137
 138         let lockfile_path = Self::lockfile_path(&base);
 139
 140         let locker = tools::ProcessLocker::new(&lockfile_path)?;
 141
 142         Ok(ChunkStore {
 143             name: name.to_owned(),
 144             base,
 145             chunk_dir,
 146             locker,
 147             mutex: Mutex::new(false)
 148         })
 149     }
 150
 151     pub fn touch_chunk(&self, digest: &[u8; 32]) -> Result<(), Error> {
 152         self.cond_touch_chunk(digest, true)?;
 153         Ok(())
 154     }
 155
 156     pub fn cond_touch_chunk(&self, digest: &[u8; 32], fail_if_not_exist: bool) -> Result<bool, Error> {
 157
 158         let (chunk_path, _digest_str) = self.chunk_path(digest);
 159
 160         const UTIME_NOW: i64 = ((1 << 30) - 1);
 161         const UTIME_OMIT: i64 = ((1 << 30) - 2);
 162
 163         let times: [libc::timespec; 2] = [
 164             libc::timespec { tv_sec: 0, tv_nsec: UTIME_NOW },
 165             libc::timespec { tv_sec: 0, tv_nsec: UTIME_OMIT }
 166         ];
 167
 168         use nix::NixPath;
 169
 170         let res = chunk_path.with_nix_path(|cstr| unsafe {
 171             let tmp = libc::utimensat(-1, cstr.as_ptr(), &times[0], libc::AT_SYMLINK_NOFOLLOW);
 172             nix::errno::Errno::result(tmp)
 173         })?;
 174
 175         if let Err(err) = res {
 176             if !fail_if_not_exist && err.as_errno() == Some(nix::errno::Errno::ENOENT) {
 177                 return Ok(false);
 178             }
 179
 180             bail!("updata atime failed for chunk {:?} - {}", chunk_path, err);
 181         }
 182
 183         Ok(true)
 184     }
 185
 186     pub fn read_chunk(&self, digest: &[u8; 32]) -> Result<DataBlob, Error> {
 187
 188         let (chunk_path, digest_str) = self.chunk_path(digest);
 189         let mut file = std::fs::File::open(&chunk_path)
 190             .map_err(|err| {
 191                 format_err!(
 192                     "store '{}', unable to read chunk '{}' - {}",
 193                     self.name,
 194                     digest_str,
 195                     err,
 196                 )
 197             })?;
 198
 199         DataBlob::load(&mut file)
 200     }
 201
 202     pub fn get_chunk_iterator(
 203         &self,
 204     ) -> Result<
 205         impl Iterator<Item = (Result<tools::fs::ReadDirEntry, Error>, usize)> + std::iter::FusedIterator,
 206         Error
 207     > {
 208         use nix::dir::Dir;
 209         use nix::fcntl::OFlag;
 210         use nix::sys::stat::Mode;
 211
 212         let base_handle = Dir::open(&self.chunk_dir, OFlag::O_RDONLY, Mode::empty())
 213             .map_err(|err| {
 214                 format_err!(
 215                     "unable to open store '{}' chunk dir {:?} - {}",
 216                     self.name,
 217                     self.chunk_dir,
 218                     err,
 219                 )
 220             })?;
 221
 222         let mut done = false;
 223         let mut inner: Option<tools::fs::ReadDir> = None;
 224         let mut at = 0;
 225         let mut percentage = 0;
 226         Ok(std::iter::from_fn(move || {
 227             if done {
 228                 return None;
 229             }
 230
 231             loop {
 232                 if let Some(ref mut inner) = inner {
 233                     match inner.next() {
 234                         Some(Ok(entry)) => {
 235                             // skip files if they're not a hash
 236                             let bytes = entry.file_name().to_bytes();
 237                             if bytes.len() != 64 {
 238                                 continue;
 239                             }
 240                             if !bytes.iter().all(u8::is_ascii_hexdigit) {
 241                                 continue;
 242                             }
 243                             return Some((Ok(entry), percentage));
 244                         }
 245                         Some(Err(err)) => {
 246                             // stop after first error
 247                             done = true;
 248                             // and pass the error through:
 249                             return Some((Err(err), percentage));
 250                         }
 251                         None => (), // open next directory
 252                     }
 253                 }
 254
 255                 inner = None;
 256
 257                 if at == 0x10000 {
 258                     done = true;
 259                     return None;
 260                 }
 261
 262                 let subdir: &str = &format!("{:04x}", at);
 263                 percentage = (at * 100) / 0x10000;
 264                 at += 1;
 265                 match tools::fs::read_subdir(base_handle.as_raw_fd(), subdir) {
 266                     Ok(dir) => {
 267                         inner = Some(dir);
 268                         // start reading:
 269                         continue;
 270                     }
 271                     Err(ref err) if err.as_errno() == Some(nix::errno::Errno::ENOENT) => {
 272                         // non-existing directories are okay, just keep going:
 273                         continue;
 274                     }
 275                     Err(err) => {
 276                         // other errors are fatal, so end our iteration
 277                         done = true;
 278                         // and pass the error through:
 279                         return Some((Err(format_err!("unable to read subdir '{}' - {}", subdir, err)), percentage));
 280                     }
 281                 }
 282             }
 283         }).fuse())
 284     }
 285
 286     pub fn oldest_writer(&self) -> Option<i64> {
 287         tools::ProcessLocker::oldest_shared_lock(self.locker.clone())
 288     }
 289
 290     pub fn sweep_unused_chunks(
 291         &self,
 292         oldest_writer: i64,
 293         status: &mut GarbageCollectionStatus,
 294         worker: &WorkerTask,
 295     ) -> Result<(), Error> {
 296         use nix::sys::stat::fstatat;
 297
 298         let now = unsafe { libc::time(std::ptr::null_mut()) };
 299
 300         let mut min_atime = now - 3600*24; // at least 24h (see mount option relatime)
 301
 302         if oldest_writer < min_atime {
 303             min_atime = oldest_writer;
 304         }
 305
 306         min_atime -= 300; // add 5 mins gap for safety
 307
 308         let mut last_percentage = 0;
 309         let mut chunk_count = 0;
 310
 311         for (entry, percentage) in self.get_chunk_iterator()? {
 312             if last_percentage != percentage {
 313                 last_percentage = percentage;
 314                 worker.log(format!("percentage done: {}, chunk count: {}", percentage, chunk_count));
 315             }
 316
 317             worker.fail_on_abort()?;
 318             tools::fail_on_shutdown()?;
 319
 320             let (dirfd, entry) = match entry {
 321                 Ok(entry) => (entry.parent_fd(), entry),
 322                 Err(err) => bail!("chunk iterator on chunk store '{}' failed - {}", self.name, err),
 323             };
 324
 325             let file_type = match entry.file_type() {
 326                 Some(file_type) => file_type,
 327                 None => bail!("unsupported file system type on chunk store '{}'", self.name),
 328             };
 329             if file_type != nix::dir::Type::File {
 330                 continue;
 331             }
 332
 333             chunk_count += 1;
 334
 335             let filename = entry.file_name();
 336
 337             let lock = self.mutex.lock();
 338
 339             if let Ok(stat) = fstatat(dirfd, filename, nix::fcntl::AtFlags::AT_SYMLINK_NOFOLLOW) {
 340                 if stat.st_atime < min_atime {
 341                     //let age = now - stat.st_atime;
 342                     //println!("UNLINK {}  {:?}", age/(3600*24), filename);
 343                     let res = unsafe { libc::unlinkat(dirfd, filename.as_ptr(), 0) };
 344                     if res != 0 {
 345                         let err = nix::Error::last();
 346                         bail!(
 347                             "unlink chunk {:?} failed on store '{}' - {}",
 348                             filename,
 349                             self.name,
 350                             err,
 351                         );
 352                     }
 353                     status.removed_chunks += 1;
 354                     status.removed_bytes += stat.st_size as u64;
 355                 } else {
 356                     if stat.st_atime < oldest_writer {
 357                         status.pending_chunks += 1;
 358                         status.pending_bytes += stat.st_size as u64;
 359                     } else {
 360                         status.disk_chunks += 1;
 361                         status.disk_bytes += stat.st_size as u64;
 362                      }
 363                 }
 364             }
 365             drop(lock);
 366         }
 367
 368         Ok(())
 369     }
 370
 371     pub fn insert_chunk(
 372         &self,
 373         chunk: &DataBlob,
 374         digest: &[u8; 32],
 375     ) -> Result<(bool, u64), Error> {
 376
 377         //println!("DIGEST {}", proxmox::tools::digest_to_hex(digest));
 378
 379         let (chunk_path, digest_str) = self.chunk_path(digest);
 380
 381         let lock = self.mutex.lock();
 382
 383         if let Ok(metadata) = std::fs::metadata(&chunk_path) {
 384             if metadata.is_file() {
 385                 return Ok((true, metadata.len()));
 386             } else {
 387                 bail!("Got unexpected file type on store '{}' for chunk {}", self.name, digest_str);
 388             }
 389         }
 390
 391         let mut tmp_path = chunk_path.clone();
 392         tmp_path.set_extension("tmp");
 393
 394         let mut file = std::fs::File::create(&tmp_path)?;
 395
 396         let raw_data = chunk.raw_data();
 397         let encoded_size = raw_data.len() as u64;
 398
 399         file.write_all(raw_data)?;
 400
 401         if let Err(err) = std::fs::rename(&tmp_path, &chunk_path) {
 402             if let Err(_) = std::fs::remove_file(&tmp_path)  { /* ignore */ }
 403             bail!(
 404                 "Atomic rename on store '{}' failed for chunk {} - {}",
 405                 self.name,
 406                 digest_str,
 407                 err,
 408             );
 409         }
 410
 411         drop(lock);
 412
 413         Ok((false, encoded_size))
 414     }
 415
 416     pub fn chunk_path(&self, digest:&[u8; 32]) -> (PathBuf, String) {
 417         let mut chunk_path = self.chunk_dir.clone();
 418         let prefix = digest_to_prefix(digest);
 419         chunk_path.push(&prefix);
 420         let digest_str = proxmox::tools::digest_to_hex(digest);
 421         chunk_path.push(&digest_str);
 422         (chunk_path, digest_str)
 423     }
 424
 425     pub fn relative_path(&self, path: &Path) -> PathBuf {
 426
 427         let mut full_path = self.base.clone();
 428         full_path.push(path);
 429         full_path
 430     }
 431
 432     pub fn base_path(&self) -> PathBuf {
 433         self.base.clone()
 434     }
 435
 436     pub fn try_shared_lock(&self) -> Result<tools::ProcessLockSharedGuard, Error> {
 437         tools::ProcessLocker::try_shared_lock(self.locker.clone())
 438     }
 439
 440     pub fn try_exclusive_lock(&self) -> Result<tools::ProcessLockExclusiveGuard, Error> {
 441         tools::ProcessLocker::try_exclusive_lock(self.locker.clone())
 442     }
 443 }
 444
 445
 446 #[test]
 447 fn test_chunk_store1() {
 448
 449     let mut path = std::fs::canonicalize(".").unwrap(); // we need absulute path
 450     path.push(".testdir");
 451
 452     if let Err(_e) = std::fs::remove_dir_all(".testdir") { /* ignore */ }
 453
 454     let chunk_store = ChunkStore::open("test", &path);
 455     assert!(chunk_store.is_err());
 456
 457     let user = nix::unistd::User::from_uid(nix::unistd::Uid::current()).unwrap().unwrap();
 458     let chunk_store = ChunkStore::create("test", &path, user.uid, user.gid).unwrap();
 459
 460     let (chunk, digest) = super::DataChunkBuilder::new(&[0u8, 1u8]).build().unwrap();
 461
 462     let (exists, _) = chunk_store.insert_chunk(&chunk, &digest).unwrap();
 463     assert!(!exists);
 464
 465     let (exists, _) = chunk_store.insert_chunk(&chunk, &digest).unwrap();
 466     assert!(exists);
 467
 468
 469     let chunk_store = ChunkStore::create("test", &path, user.uid, user.gid);
 470     assert!(chunk_store.is_err());
 471
 472     if let Err(_e) = std::fs::remove_dir_all(".testdir") { /* ignore */ }
 473 }