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         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!("{}%", percentage);
 108                 last_percentage = percentage;
 109             }
 110         }
 111
 112
 113         Self::open(name, base)
 114     }
 115
 116     fn lockfile_path<P: Into<PathBuf>>(base: P) -> PathBuf {
 117         let base: PathBuf = base.into();
 118
 119         let mut lockfile_path = base.clone();
 120         lockfile_path.push(".lock");
 121
 122         lockfile_path
 123     }
 124
 125     pub fn open<P: Into<PathBuf>>(name: &str, base: P) -> Result<Self, Error> {
 126
 127         let base: PathBuf = base.into();
 128
 129         if !base.is_absolute() {
 130             bail!("expected absolute path - got {:?}", base);
 131         }
 132
 133         let chunk_dir = Self::chunk_dir(&base);
 134
 135         if let Err(err) = std::fs::metadata(&chunk_dir) {
 136             bail!("unable to open chunk store '{}' at {:?} - {}", name, chunk_dir, err);
 137         }
 138
 139         let lockfile_path = Self::lockfile_path(&base);
 140
 141         let locker = tools::ProcessLocker::new(&lockfile_path)?;
 142
 143         Ok(ChunkStore {
 144             name: name.to_owned(),
 145             base,
 146             chunk_dir,
 147             locker,
 148             mutex: Mutex::new(false)
 149         })
 150     }
 151
 152     pub fn touch_chunk(&self, digest: &[u8; 32]) -> Result<(), Error> {
 153         self.cond_touch_chunk(digest, true)?;
 154         Ok(())
 155     }
 156
 157     pub fn cond_touch_chunk(&self, digest: &[u8; 32], fail_if_not_exist: bool) -> Result<bool, Error> {
 158
 159         let (chunk_path, _digest_str) = self.chunk_path(digest);
 160
 161         const UTIME_NOW: i64 = (1 << 30) - 1;
 162         const UTIME_OMIT: i64 = (1 << 30) - 2;
 163
 164         let times: [libc::timespec; 2] = [
 165             libc::timespec { tv_sec: 0, tv_nsec: UTIME_NOW },
 166             libc::timespec { tv_sec: 0, tv_nsec: UTIME_OMIT }
 167         ];
 168
 169         use nix::NixPath;
 170
 171         let res = chunk_path.with_nix_path(|cstr| unsafe {
 172             let tmp = libc::utimensat(-1, cstr.as_ptr(), &times[0], libc::AT_SYMLINK_NOFOLLOW);
 173             nix::errno::Errno::result(tmp)
 174         })?;
 175
 176         if let Err(err) = res {
 177             if !fail_if_not_exist && err.as_errno() == Some(nix::errno::Errno::ENOENT) {
 178                 return Ok(false);
 179             }
 180
 181             bail!("update atime failed for chunk {:?} - {}", chunk_path, err);
 182         }
 183
 184         Ok(true)
 185     }
 186
 187     pub fn get_chunk_iterator(
 188         &self,
 189     ) -> Result<
 190         impl Iterator<Item = (Result<tools::fs::ReadDirEntry, Error>, usize, bool)> + std::iter::FusedIterator,
 191         Error
 192     > {
 193         use nix::dir::Dir;
 194         use nix::fcntl::OFlag;
 195         use nix::sys::stat::Mode;
 196
 197         let base_handle = Dir::open(&self.chunk_dir, OFlag::O_RDONLY, Mode::empty())
 198             .map_err(|err| {
 199                 format_err!(
 200                     "unable to open store '{}' chunk dir {:?} - {}",
 201                     self.name,
 202                     self.chunk_dir,
 203                     err,
 204                 )
 205             })?;
 206
 207         let mut done = false;
 208         let mut inner: Option<tools::fs::ReadDir> = None;
 209         let mut at = 0;
 210         let mut percentage = 0;
 211         Ok(std::iter::from_fn(move || {
 212             if done {
 213                 return None;
 214             }
 215
 216             loop {
 217                 if let Some(ref mut inner) = inner {
 218                     match inner.next() {
 219                         Some(Ok(entry)) => {
 220                             // skip files if they're not a hash
 221                             let bytes = entry.file_name().to_bytes();
 222                             if bytes.len() != 64 && bytes.len() != 64 + ".0.bad".len() {
 223                                 continue;
 224                             }
 225                             if !bytes.iter().take(64).all(u8::is_ascii_hexdigit) {
 226                                 continue;
 227                             }
 228
 229                             let bad = bytes.ends_with(".bad".as_bytes());
 230                             return Some((Ok(entry), percentage, bad));
 231                         }
 232                         Some(Err(err)) => {
 233                             // stop after first error
 234                             done = true;
 235                             // and pass the error through:
 236                             return Some((Err(err), percentage, false));
 237                         }
 238                         None => (), // open next directory
 239                     }
 240                 }
 241
 242                 inner = None;
 243
 244                 if at == 0x10000 {
 245                     done = true;
 246                     return None;
 247                 }
 248
 249                 let subdir: &str = &format!("{:04x}", at);
 250                 percentage = (at * 100) / 0x10000;
 251                 at += 1;
 252                 match tools::fs::read_subdir(base_handle.as_raw_fd(), subdir) {
 253                     Ok(dir) => {
 254                         inner = Some(dir);
 255                         // start reading:
 256                         continue;
 257                     }
 258                     Err(ref err) if err.as_errno() == Some(nix::errno::Errno::ENOENT) => {
 259                         // non-existing directories are okay, just keep going:
 260                         continue;
 261                     }
 262                     Err(err) => {
 263                         // other errors are fatal, so end our iteration
 264                         done = true;
 265                         // and pass the error through:
 266                         return Some((Err(format_err!("unable to read subdir '{}' - {}", subdir, err)), percentage, false));
 267                     }
 268                 }
 269             }
 270         }).fuse())
 271     }
 272
 273     pub fn oldest_writer(&self) -> Option<i64> {
 274         tools::ProcessLocker::oldest_shared_lock(self.locker.clone())
 275     }
 276
 277     pub fn sweep_unused_chunks(
 278         &self,
 279         oldest_writer: i64,
 280         phase1_start_time: i64,
 281         status: &mut GarbageCollectionStatus,
 282         worker: &WorkerTask,
 283     ) -> Result<(), Error> {
 284         use nix::sys::stat::fstatat;
 285         use nix::unistd::{unlinkat, UnlinkatFlags};
 286
 287         let mut min_atime = phase1_start_time - 3600*24; // at least 24h (see mount option relatime)
 288
 289         if oldest_writer < min_atime {
 290             min_atime = oldest_writer;
 291         }
 292
 293         min_atime -= 300; // add 5 mins gap for safety
 294
 295         let mut last_percentage = 0;
 296         let mut chunk_count = 0;
 297
 298         for (entry, percentage, bad) in self.get_chunk_iterator()? {
 299             if last_percentage != percentage {
 300                 last_percentage = percentage;
 301                 worker.log(format!("percentage done: phase2 {}% (processed {} chunks)", percentage, chunk_count));
 302             }
 303
 304             worker.fail_on_abort()?;
 305             tools::fail_on_shutdown()?;
 306
 307             let (dirfd, entry) = match entry {
 308                 Ok(entry) => (entry.parent_fd(), entry),
 309                 Err(err) => bail!("chunk iterator on chunk store '{}' failed - {}", self.name, err),
 310             };
 311
 312             let file_type = match entry.file_type() {
 313                 Some(file_type) => file_type,
 314                 None => bail!("unsupported file system type on chunk store '{}'", self.name),
 315             };
 316             if file_type != nix::dir::Type::File {
 317                 continue;
 318             }
 319
 320             chunk_count += 1;
 321
 322             let filename = entry.file_name();
 323
 324             let lock = self.mutex.lock();
 325
 326             if let Ok(stat) = fstatat(dirfd, filename, nix::fcntl::AtFlags::AT_SYMLINK_NOFOLLOW) {
 327                 if bad {
 328                     // filename validity checked in iterator
 329                     let orig_filename = std::ffi::CString::new(&filename.to_bytes()[..64])?;
 330                     match fstatat(
 331                         dirfd,
 332                         orig_filename.as_c_str(),
 333                         nix::fcntl::AtFlags::AT_SYMLINK_NOFOLLOW)
 334                     {
 335                         Ok(_) => {
 336                             match unlinkat(Some(dirfd), filename, UnlinkatFlags::NoRemoveDir) {
 337                                 Err(err) =>
 338                                     worker.warn(format!(
 339                                         "unlinking corrupt chunk {:?} failed on store '{}' - {}",
 340                                         filename,
 341                                         self.name,
 342                                         err,
 343                                     )),
 344                                 Ok(_) => {
 345                                     status.removed_bad += 1;
 346                                     status.removed_bytes += stat.st_size as u64;
 347                                 }
 348                             }
 349                         },
 350                         Err(nix::Error::Sys(nix::errno::Errno::ENOENT)) => {
 351                             // chunk hasn't been rewritten yet, keep .bad file
 352                         },
 353                         Err(err) => {
 354                             // some other error, warn user and keep .bad file around too
 355                             worker.warn(format!(
 356                                 "error during stat on '{:?}' - {}",
 357                                 orig_filename,
 358                                 err,
 359                             ));
 360                         }
 361                     }
 362                 } else if stat.st_atime < min_atime {
 363                     //let age = now - stat.st_atime;
 364                     //println!("UNLINK {}  {:?}", age/(3600*24), filename);
 365                     if let Err(err) = unlinkat(Some(dirfd), filename, UnlinkatFlags::NoRemoveDir) {
 366                         bail!(
 367                             "unlinking chunk {:?} failed on store '{}' - {}",
 368                             filename,
 369                             self.name,
 370                             err,
 371                         );
 372                     }
 373                     status.removed_chunks += 1;
 374                     status.removed_bytes += stat.st_size as u64;
 375                 } else {
 376                     if stat.st_atime < oldest_writer {
 377                         status.pending_chunks += 1;
 378                         status.pending_bytes += stat.st_size as u64;
 379                     } else {
 380                         status.disk_chunks += 1;
 381                         status.disk_bytes += stat.st_size as u64;
 382                      }
 383                 }
 384             }
 385             drop(lock);
 386         }
 387
 388         Ok(())
 389     }
 390
 391     pub fn insert_chunk(
 392         &self,
 393         chunk: &DataBlob,
 394         digest: &[u8; 32],
 395     ) -> Result<(bool, u64), Error> {
 396
 397         //println!("DIGEST {}", proxmox::tools::digest_to_hex(digest));
 398
 399         let (chunk_path, digest_str) = self.chunk_path(digest);
 400
 401         let lock = self.mutex.lock();
 402
 403         if let Ok(metadata) = std::fs::metadata(&chunk_path) {
 404             if metadata.is_file() {
 405                 self.touch_chunk(digest)?;
 406                 return Ok((true, metadata.len()));
 407             } else {
 408                 bail!("Got unexpected file type on store '{}' for chunk {}", self.name, digest_str);
 409             }
 410         }
 411
 412         let mut tmp_path = chunk_path.clone();
 413         tmp_path.set_extension("tmp");
 414
 415         let mut file = std::fs::File::create(&tmp_path)?;
 416
 417         let raw_data = chunk.raw_data();
 418         let encoded_size = raw_data.len() as u64;
 419
 420         file.write_all(raw_data)?;
 421
 422         if let Err(err) = std::fs::rename(&tmp_path, &chunk_path) {
 423             if let Err(_) = std::fs::remove_file(&tmp_path)  { /* ignore */ }
 424             bail!(
 425                 "Atomic rename on store '{}' failed for chunk {} - {}",
 426                 self.name,
 427                 digest_str,
 428                 err,
 429             );
 430         }
 431
 432         drop(lock);
 433
 434         Ok((false, encoded_size))
 435     }
 436
 437     pub fn chunk_path(&self, digest:&[u8; 32]) -> (PathBuf, String) {
 438         let mut chunk_path = self.chunk_dir.clone();
 439         let prefix = digest_to_prefix(digest);
 440         chunk_path.push(&prefix);
 441         let digest_str = proxmox::tools::digest_to_hex(digest);
 442         chunk_path.push(&digest_str);
 443         (chunk_path, digest_str)
 444     }
 445
 446     pub fn relative_path(&self, path: &Path) -> PathBuf {
 447
 448         let mut full_path = self.base.clone();
 449         full_path.push(path);
 450         full_path
 451     }
 452
 453     pub fn name(&self) -> &str {
 454         &self.name
 455     }
 456
 457     pub fn base_path(&self) -> PathBuf {
 458         self.base.clone()
 459     }
 460
 461     pub fn try_shared_lock(&self) -> Result<tools::ProcessLockSharedGuard, Error> {
 462         tools::ProcessLocker::try_shared_lock(self.locker.clone())
 463     }
 464
 465     pub fn try_exclusive_lock(&self) -> Result<tools::ProcessLockExclusiveGuard, Error> {
 466         tools::ProcessLocker::try_exclusive_lock(self.locker.clone())
 467     }
 468 }
 469
 470
 471 #[test]
 472 fn test_chunk_store1() {
 473
 474     let mut path = std::fs::canonicalize(".").unwrap(); // we need absulute path
 475     path.push(".testdir");
 476
 477     if let Err(_e) = std::fs::remove_dir_all(".testdir") { /* ignore */ }
 478
 479     let chunk_store = ChunkStore::open("test", &path);
 480     assert!(chunk_store.is_err());
 481
 482     let user = nix::unistd::User::from_uid(nix::unistd::Uid::current()).unwrap().unwrap();
 483     let chunk_store = ChunkStore::create("test", &path, user.uid, user.gid).unwrap();
 484
 485     let (chunk, digest) = super::DataChunkBuilder::new(&[0u8, 1u8]).build().unwrap();
 486
 487     let (exists, _) = chunk_store.insert_chunk(&chunk, &digest).unwrap();
 488     assert!(!exists);
 489
 490     let (exists, _) = chunk_store.insert_chunk(&chunk, &digest).unwrap();
 491     assert!(exists);
 492
 493
 494     let chunk_store = ChunkStore::create("test", &path, user.uid, user.gid);
 495     assert!(chunk_store.is_err());
 496
 497     if let Err(_e) = std::fs::remove_dir_all(".testdir") { /* ignore */ }
 498 }