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::task::TaskState;
  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         match create_path(&base, Some(default_options.clone()), Some(options.clone())) {
  84             Err(err) => bail!("unable to create chunk store '{}' at {:?} - {}", name, base, err),
  85             Ok(res) => if ! res  { nix::unistd::chown(&base, Some(uid), Some(gid))? },
  86         }
  87
  88         if let Err(err) = create_dir(&chunk_dir, options.clone()) {
  89             bail!("unable to create chunk store '{}' subdir {:?} - {}", name, chunk_dir, err);
  90         }
  91
  92         // create lock file with correct owner/group
  93         let lockfile_path = Self::lockfile_path(&base);
  94         proxmox::tools::fs::replace_file(lockfile_path, b"", options.clone())?;
  95
  96         // create 64*1024 subdirs
  97         let mut last_percentage = 0;
  98
  99         for i in 0..64*1024 {
 100             let mut l1path = chunk_dir.clone();
 101             l1path.push(format!("{:04x}", i));
 102             if let Err(err) = create_dir(&l1path, options.clone()) {
 103                 bail!("unable to create chunk store '{}' subdir {:?} - {}", name, l1path, err);
 104             }
 105             let percentage = (i*100)/(64*1024);
 106             if percentage != last_percentage {
 107                 // eprintln!("ChunkStore::create {}%", percentage);
 108                 last_percentage = percentage;
 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!("update atime failed for chunk {:?} - {}", chunk_path, err);
 181         }
 182
 183         Ok(true)
 184     }
 185
 186     pub fn get_chunk_iterator(
 187         &self,
 188     ) -> Result<
 189         impl Iterator<Item = (Result<tools::fs::ReadDirEntry, Error>, usize, bool)> + std::iter::FusedIterator,
 190         Error
 191     > {
 192         use nix::dir::Dir;
 193         use nix::fcntl::OFlag;
 194         use nix::sys::stat::Mode;
 195
 196         let base_handle = Dir::open(&self.chunk_dir, OFlag::O_RDONLY, Mode::empty())
 197             .map_err(|err| {
 198                 format_err!(
 199                     "unable to open store '{}' chunk dir {:?} - {}",
 200                     self.name,
 201                     self.chunk_dir,
 202                     err,
 203                 )
 204             })?;
 205
 206         let mut done = false;
 207         let mut inner: Option<tools::fs::ReadDir> = None;
 208         let mut at = 0;
 209         let mut percentage = 0;
 210         Ok(std::iter::from_fn(move || {
 211             if done {
 212                 return None;
 213             }
 214
 215             loop {
 216                 if let Some(ref mut inner) = inner {
 217                     match inner.next() {
 218                         Some(Ok(entry)) => {
 219                             // skip files if they're not a hash
 220                             let bytes = entry.file_name().to_bytes();
 221                             if bytes.len() != 64 && bytes.len() != 64 + ".0.bad".len() {
 222                                 continue;
 223                             }
 224                             if !bytes.iter().take(64).all(u8::is_ascii_hexdigit) {
 225                                 continue;
 226                             }
 227
 228                             let bad = bytes.ends_with(".bad".as_bytes());
 229                             return Some((Ok(entry), percentage, bad));
 230                         }
 231                         Some(Err(err)) => {
 232                             // stop after first error
 233                             done = true;
 234                             // and pass the error through:
 235                             return Some((Err(err), percentage, false));
 236                         }
 237                         None => (), // open next directory
 238                     }
 239                 }
 240
 241                 inner = None;
 242
 243                 if at == 0x10000 {
 244                     done = true;
 245                     return None;
 246                 }
 247
 248                 let subdir: &str = &format!("{:04x}", at);
 249                 percentage = (at * 100) / 0x10000;
 250                 at += 1;
 251                 match tools::fs::read_subdir(base_handle.as_raw_fd(), subdir) {
 252                     Ok(dir) => {
 253                         inner = Some(dir);
 254                         // start reading:
 255                         continue;
 256                     }
 257                     Err(ref err) if err.as_errno() == Some(nix::errno::Errno::ENOENT) => {
 258                         // non-existing directories are okay, just keep going:
 259                         continue;
 260                     }
 261                     Err(err) => {
 262                         // other errors are fatal, so end our iteration
 263                         done = true;
 264                         // and pass the error through:
 265                         return Some((Err(format_err!("unable to read subdir '{}' - {}", subdir, err)), percentage, false));
 266                     }
 267                 }
 268             }
 269         }).fuse())
 270     }
 271
 272     pub fn oldest_writer(&self) -> Option<i64> {
 273         tools::ProcessLocker::oldest_shared_lock(self.locker.clone())
 274     }
 275
 276     pub fn sweep_unused_chunks(
 277         &self,
 278         oldest_writer: i64,
 279         phase1_start_time: i64,
 280         status: &mut GarbageCollectionStatus,
 281         worker: &dyn TaskState,
 282     ) -> Result<(), Error> {
 283         use nix::sys::stat::fstatat;
 284         use nix::unistd::{unlinkat, UnlinkatFlags};
 285
 286         let mut min_atime = phase1_start_time - 3600*24; // at least 24h (see mount option relatime)
 287
 288         if oldest_writer < min_atime {
 289             min_atime = oldest_writer;
 290         }
 291
 292         min_atime -= 300; // add 5 mins gap for safety
 293
 294         let mut last_percentage = 0;
 295         let mut chunk_count = 0;
 296
 297         for (entry, percentage, bad) in self.get_chunk_iterator()? {
 298             if last_percentage != percentage {
 299                 last_percentage = percentage;
 300                 crate::task_log!(
 301                     worker,
 302                     "percentage done: phase2 {}% (processed {} chunks)",
 303                     percentage,
 304                     chunk_count,
 305                 );
 306             }
 307
 308             worker.check_abort()?;
 309             tools::fail_on_shutdown()?;
 310
 311             let (dirfd, entry) = match entry {
 312                 Ok(entry) => (entry.parent_fd(), entry),
 313                 Err(err) => bail!("chunk iterator on chunk store '{}' failed - {}", self.name, err),
 314             };
 315
 316             let file_type = match entry.file_type() {
 317                 Some(file_type) => file_type,
 318                 None => bail!("unsupported file system type on chunk store '{}'", self.name),
 319             };
 320             if file_type != nix::dir::Type::File {
 321                 continue;
 322             }
 323
 324             chunk_count += 1;
 325
 326             let filename = entry.file_name();
 327
 328             let lock = self.mutex.lock();
 329
 330             if let Ok(stat) = fstatat(dirfd, filename, nix::fcntl::AtFlags::AT_SYMLINK_NOFOLLOW) {
 331                 if bad {
 332                     // filename validity checked in iterator
 333                     let orig_filename = std::ffi::CString::new(&filename.to_bytes()[..64])?;
 334                     match fstatat(
 335                         dirfd,
 336                         orig_filename.as_c_str(),
 337                         nix::fcntl::AtFlags::AT_SYMLINK_NOFOLLOW)
 338                     {
 339                         Ok(_) => {
 340                             match unlinkat(Some(dirfd), filename, UnlinkatFlags::NoRemoveDir) {
 341                                 Err(err) =>
 342                                     crate::task_warn!(
 343                                         worker,
 344                                         "unlinking corrupt chunk {:?} failed on store '{}' - {}",
 345                                         filename,
 346                                         self.name,
 347                                         err,
 348                                     ),
 349                                 Ok(_) => {
 350                                     status.removed_bad += 1;
 351                                     status.removed_bytes += stat.st_size as u64;
 352                                 }
 353                             }
 354                         },
 355                         Err(nix::Error::Sys(nix::errno::Errno::ENOENT)) => {
 356                             // chunk hasn't been rewritten yet, keep .bad file
 357                             status.still_bad += 1;
 358                         },
 359                         Err(err) => {
 360                             // some other error, warn user and keep .bad file around too
 361                             status.still_bad += 1;
 362                             crate::task_warn!(
 363                                 worker,
 364                                 "error during stat on '{:?}' - {}",
 365                                 orig_filename,
 366                                 err,
 367                             );
 368                         }
 369                     }
 370                 } else if stat.st_atime < min_atime {
 371                     //let age = now - stat.st_atime;
 372                     //println!("UNLINK {}  {:?}", age/(3600*24), filename);
 373                     if let Err(err) = unlinkat(Some(dirfd), filename, UnlinkatFlags::NoRemoveDir) {
 374                         bail!(
 375                             "unlinking chunk {:?} failed on store '{}' - {}",
 376                             filename,
 377                             self.name,
 378                             err,
 379                         );
 380                     }
 381                     status.removed_chunks += 1;
 382                     status.removed_bytes += stat.st_size as u64;
 383                 } else if stat.st_atime < oldest_writer {
 384                     status.pending_chunks += 1;
 385                     status.pending_bytes += stat.st_size as u64;
 386                 } else {
 387                     status.disk_chunks += 1;
 388                     status.disk_bytes += stat.st_size as u64;
 389                 }
 390             }
 391             drop(lock);
 392         }
 393
 394         Ok(())
 395     }
 396
 397     pub fn insert_chunk(
 398         &self,
 399         chunk: &DataBlob,
 400         digest: &[u8; 32],
 401     ) -> Result<(bool, u64), Error> {
 402
 403         //println!("DIGEST {}", proxmox::tools::digest_to_hex(digest));
 404
 405         let (chunk_path, digest_str) = self.chunk_path(digest);
 406
 407         let lock = self.mutex.lock();
 408
 409         if let Ok(metadata) = std::fs::metadata(&chunk_path) {
 410             if metadata.is_file() {
 411                 self.touch_chunk(digest)?;
 412                 return Ok((true, metadata.len()));
 413             } else {
 414                 bail!("Got unexpected file type on store '{}' for chunk {}", self.name, digest_str);
 415             }
 416         }
 417
 418         let mut tmp_path = chunk_path.clone();
 419         tmp_path.set_extension("tmp");
 420
 421         let mut file = std::fs::File::create(&tmp_path)?;
 422
 423         let raw_data = chunk.raw_data();
 424         let encoded_size = raw_data.len() as u64;
 425
 426         file.write_all(raw_data)?;
 427
 428         if let Err(err) = std::fs::rename(&tmp_path, &chunk_path) {
 429             if let Err(_) = std::fs::remove_file(&tmp_path)  { /* ignore */ }
 430             bail!(
 431                 "Atomic rename on store '{}' failed for chunk {} - {}",
 432                 self.name,
 433                 digest_str,
 434                 err,
 435             );
 436         }
 437
 438         drop(lock);
 439
 440         Ok((false, encoded_size))
 441     }
 442
 443     pub fn chunk_path(&self, digest:&[u8; 32]) -> (PathBuf, String) {
 444         let mut chunk_path = self.chunk_dir.clone();
 445         let prefix = digest_to_prefix(digest);
 446         chunk_path.push(&prefix);
 447         let digest_str = proxmox::tools::digest_to_hex(digest);
 448         chunk_path.push(&digest_str);
 449         (chunk_path, digest_str)
 450     }
 451
 452     pub fn relative_path(&self, path: &Path) -> PathBuf {
 453
 454         let mut full_path = self.base.clone();
 455         full_path.push(path);
 456         full_path
 457     }
 458
 459     pub fn name(&self) -> &str {
 460         &self.name
 461     }
 462
 463     pub fn base_path(&self) -> PathBuf {
 464         self.base.clone()
 465     }
 466
 467     pub fn try_shared_lock(&self) -> Result<tools::ProcessLockSharedGuard, Error> {
 468         tools::ProcessLocker::try_shared_lock(self.locker.clone())
 469     }
 470
 471     pub fn try_exclusive_lock(&self) -> Result<tools::ProcessLockExclusiveGuard, Error> {
 472         tools::ProcessLocker::try_exclusive_lock(self.locker.clone())
 473     }
 474 }
 475
 476
 477 #[test]
 478 fn test_chunk_store1() {
 479
 480     let mut path = std::fs::canonicalize(".").unwrap(); // we need absulute path
 481     path.push(".testdir");
 482
 483     if let Err(_e) = std::fs::remove_dir_all(".testdir") { /* ignore */ }
 484
 485     let chunk_store = ChunkStore::open("test", &path);
 486     assert!(chunk_store.is_err());
 487
 488     let user = nix::unistd::User::from_uid(nix::unistd::Uid::current()).unwrap().unwrap();
 489     let chunk_store = ChunkStore::create("test", &path, user.uid, user.gid).unwrap();
 490
 491     let (chunk, digest) = super::DataChunkBuilder::new(&[0u8, 1u8]).build().unwrap();
 492
 493     let (exists, _) = chunk_store.insert_chunk(&chunk, &digest).unwrap();
 494     assert!(!exists);
 495
 496     let (exists, _) = chunk_store.insert_chunk(&chunk, &digest).unwrap();
 497     assert!(exists);
 498
 499
 500     let chunk_store = ChunkStore::create("test", &path, user.uid, user.gid);
 501     assert!(chunk_store.is_err());
 502
 503     if let Err(_e) = std::fs::remove_dir_all(".testdir") { /* ignore */ }
 504 }