src/backup/datastore.rs

   1 use std::collections::{HashSet, HashMap};
   2 use std::io::{self, Write};
   3 use std::path::{Path, PathBuf};
   4 use std::sync::{Arc, Mutex};
   5 use std::convert::TryFrom;
   6 use std::time::Duration;
   7 use std::fs::File;
   8
   9 use anyhow::{bail, format_err, Error};
  10 use lazy_static::lazy_static;
  11
  12 use proxmox::tools::fs::{replace_file, file_read_optional_string, CreateOptions, open_file_locked};
  13
  14 use super::backup_info::{BackupGroup, BackupDir};
  15 use super::chunk_store::ChunkStore;
  16 use super::dynamic_index::{DynamicIndexReader, DynamicIndexWriter};
  17 use super::fixed_index::{FixedIndexReader, FixedIndexWriter};
  18 use super::manifest::{MANIFEST_BLOB_NAME, MANIFEST_LOCK_NAME, CLIENT_LOG_BLOB_NAME, BackupManifest};
  19 use super::index::*;
  20 use super::{DataBlob, ArchiveType, archive_type};
  21 use crate::config::datastore::{self, DataStoreConfig};
  22 use crate::task::TaskState;
  23 use crate::tools;
  24 use crate::tools::format::HumanByte;
  25 use crate::tools::fs::{lock_dir_noblock, DirLockGuard};
  26 use crate::api2::types::{GarbageCollectionStatus, Userid};
  27 use crate::server::UPID;
  28
  29 lazy_static! {
  30     static ref DATASTORE_MAP: Mutex<HashMap<String, Arc<DataStore>>> = Mutex::new(HashMap::new());
  31 }
  32
  33 /// Datastore Management
  34 ///
  35 /// A Datastore can store severals backups, and provides the
  36 /// management interface for backup.
  37 pub struct DataStore {
  38     chunk_store: Arc<ChunkStore>,
  39     gc_mutex: Mutex<bool>,
  40     last_gc_status: Mutex<GarbageCollectionStatus>,
  41     verify_new: bool,
  42 }
  43
  44 impl DataStore {
  45
  46     pub fn lookup_datastore(name: &str) -> Result<Arc<DataStore>, Error> {
  47
  48         let (config, _digest) = datastore::config()?;
  49         let config: datastore::DataStoreConfig = config.lookup("datastore", name)?;
  50         let path = PathBuf::from(&config.path);
  51
  52         let mut map = DATASTORE_MAP.lock().unwrap();
  53
  54         if let Some(datastore) = map.get(name) {
  55             // Compare Config - if changed, create new Datastore object!
  56             if datastore.chunk_store.base == path &&
  57                 datastore.verify_new == config.verify_new.unwrap_or(false)
  58             {
  59                 return Ok(datastore.clone());
  60             }
  61         }
  62
  63         let datastore = DataStore::open_with_path(name, &path, config)?;
  64
  65         let datastore = Arc::new(datastore);
  66         map.insert(name.to_string(), datastore.clone());
  67
  68         Ok(datastore)
  69     }
  70
  71     fn open_with_path(store_name: &str, path: &Path, config: DataStoreConfig) -> Result<Self, Error> {
  72         let chunk_store = ChunkStore::open(store_name, path)?;
  73
  74         let mut gc_status_path = chunk_store.base_path();
  75         gc_status_path.push(".gc-status");
  76
  77         let gc_status = if let Some(state) = file_read_optional_string(gc_status_path)? {
  78             match serde_json::from_str(&state) {
  79                 Ok(state) => state,
  80                 Err(err) => {
  81                     eprintln!("error reading gc-status: {}", err);
  82                     GarbageCollectionStatus::default()
  83                 }
  84             }
  85         } else {
  86             GarbageCollectionStatus::default()
  87         };
  88
  89         Ok(Self {
  90             chunk_store: Arc::new(chunk_store),
  91             gc_mutex: Mutex::new(false),
  92             last_gc_status: Mutex::new(gc_status),
  93             verify_new: config.verify_new.unwrap_or(false),
  94         })
  95     }
  96
  97     pub fn get_chunk_iterator(
  98         &self,
  99     ) -> Result<
 100         impl Iterator<Item = (Result<tools::fs::ReadDirEntry, Error>, usize, bool)>,
 101         Error
 102     > {
 103         self.chunk_store.get_chunk_iterator()
 104     }
 105
 106     pub fn create_fixed_writer<P: AsRef<Path>>(&self, filename: P, size: usize, chunk_size: usize) -> Result<FixedIndexWriter, Error> {
 107
 108         let index = FixedIndexWriter::create(self.chunk_store.clone(), filename.as_ref(), size, chunk_size)?;
 109
 110         Ok(index)
 111     }
 112
 113     pub fn open_fixed_reader<P: AsRef<Path>>(&self, filename: P) -> Result<FixedIndexReader, Error> {
 114
 115         let full_path =  self.chunk_store.relative_path(filename.as_ref());
 116
 117         let index = FixedIndexReader::open(&full_path)?;
 118
 119         Ok(index)
 120     }
 121
 122     pub fn create_dynamic_writer<P: AsRef<Path>>(
 123         &self, filename: P,
 124     ) -> Result<DynamicIndexWriter, Error> {
 125
 126         let index = DynamicIndexWriter::create(
 127             self.chunk_store.clone(), filename.as_ref())?;
 128
 129         Ok(index)
 130     }
 131
 132     pub fn open_dynamic_reader<P: AsRef<Path>>(&self, filename: P) -> Result<DynamicIndexReader, Error> {
 133
 134         let full_path =  self.chunk_store.relative_path(filename.as_ref());
 135
 136         let index = DynamicIndexReader::open(&full_path)?;
 137
 138         Ok(index)
 139     }
 140
 141     pub fn open_index<P>(&self, filename: P) -> Result<Box<dyn IndexFile + Send>, Error>
 142     where
 143         P: AsRef<Path>,
 144     {
 145         let filename = filename.as_ref();
 146         let out: Box<dyn IndexFile + Send> =
 147             match archive_type(filename)? {
 148                 ArchiveType::DynamicIndex => Box::new(self.open_dynamic_reader(filename)?),
 149                 ArchiveType::FixedIndex => Box::new(self.open_fixed_reader(filename)?),
 150                 _ => bail!("cannot open index file of unknown type: {:?}", filename),
 151             };
 152         Ok(out)
 153     }
 154
 155     pub fn name(&self) -> &str {
 156         self.chunk_store.name()
 157     }
 158
 159     pub fn base_path(&self) -> PathBuf {
 160         self.chunk_store.base_path()
 161     }
 162
 163     /// Cleanup a backup directory
 164     ///
 165     /// Removes all files not mentioned in the manifest.
 166     pub fn cleanup_backup_dir(&self, backup_dir: &BackupDir, manifest: &BackupManifest
 167     ) ->  Result<(), Error> {
 168
 169         let mut full_path = self.base_path();
 170         full_path.push(backup_dir.relative_path());
 171
 172         let mut wanted_files = HashSet::new();
 173         wanted_files.insert(MANIFEST_BLOB_NAME.to_string());
 174         wanted_files.insert(CLIENT_LOG_BLOB_NAME.to_string());
 175         manifest.files().iter().for_each(|item| { wanted_files.insert(item.filename.clone()); });
 176
 177         for item in tools::fs::read_subdir(libc::AT_FDCWD, &full_path)? {
 178             if let Ok(item) = item {
 179                 if let Some(file_type) = item.file_type() {
 180                     if file_type != nix::dir::Type::File { continue; }
 181                 }
 182                 let file_name = item.file_name().to_bytes();
 183                 if file_name == b"." || file_name == b".." { continue; };
 184
 185                 if let Ok(name) = std::str::from_utf8(file_name) {
 186                     if wanted_files.contains(name) { continue; }
 187                 }
 188                 println!("remove unused file {:?}", item.file_name());
 189                 let dirfd = item.parent_fd();
 190                 let _res = unsafe { libc::unlinkat(dirfd, item.file_name().as_ptr(), 0) };
 191             }
 192         }
 193
 194         Ok(())
 195     }
 196
 197     /// Returns the absolute path for a backup_group
 198     pub fn group_path(&self, backup_group: &BackupGroup) -> PathBuf {
 199         let mut full_path = self.base_path();
 200         full_path.push(backup_group.group_path());
 201         full_path
 202     }
 203
 204     /// Returns the absolute path for backup_dir
 205     pub fn snapshot_path(&self, backup_dir: &BackupDir) -> PathBuf {
 206         let mut full_path = self.base_path();
 207         full_path.push(backup_dir.relative_path());
 208         full_path
 209     }
 210
 211     /// Remove a complete backup group including all snapshots
 212     pub fn remove_backup_group(&self, backup_group: &BackupGroup) ->  Result<(), Error> {
 213
 214         let full_path = self.group_path(backup_group);
 215
 216         let _guard = tools::fs::lock_dir_noblock(&full_path, "backup group", "possible running backup")?;
 217
 218         log::info!("removing backup group {:?}", full_path);
 219
 220         // remove all individual backup dirs first to ensure nothing is using them
 221         for snap in backup_group.list_backups(&self.base_path())? {
 222             self.remove_backup_dir(&snap.backup_dir, false)?;
 223         }
 224
 225         // no snapshots left, we can now safely remove the empty folder
 226         std::fs::remove_dir_all(&full_path)
 227             .map_err(|err| {
 228                 format_err!(
 229                     "removing backup group directory {:?} failed - {}",
 230                     full_path,
 231                     err,
 232                 )
 233             })?;
 234
 235         Ok(())
 236     }
 237
 238     /// Remove a backup directory including all content
 239     pub fn remove_backup_dir(&self, backup_dir: &BackupDir, force: bool) ->  Result<(), Error> {
 240
 241         let full_path = self.snapshot_path(backup_dir);
 242
 243         let (_guard, _manifest_guard);
 244         if !force {
 245             _guard = lock_dir_noblock(&full_path, "snapshot", "possibly running or in use")?;
 246             _manifest_guard = self.lock_manifest(backup_dir);
 247         }
 248
 249         log::info!("removing backup snapshot {:?}", full_path);
 250         std::fs::remove_dir_all(&full_path)
 251             .map_err(|err| {
 252                 format_err!(
 253                     "removing backup snapshot {:?} failed - {}",
 254                     full_path,
 255                     err,
 256                 )
 257             })?;
 258
 259         Ok(())
 260     }
 261
 262     /// Returns the time of the last successful backup
 263     ///
 264     /// Or None if there is no backup in the group (or the group dir does not exist).
 265     pub fn last_successful_backup(&self, backup_group: &BackupGroup) -> Result<Option<i64>, Error> {
 266         let base_path = self.base_path();
 267         let mut group_path = base_path.clone();
 268         group_path.push(backup_group.group_path());
 269
 270         if group_path.exists() {
 271             backup_group.last_successful_backup(&base_path)
 272         } else {
 273             Ok(None)
 274         }
 275     }
 276
 277     /// Returns the backup owner.
 278     ///
 279     /// The backup owner is the user who first created the backup group.
 280     pub fn get_owner(&self, backup_group: &BackupGroup) -> Result<Userid, Error> {
 281         let mut full_path = self.base_path();
 282         full_path.push(backup_group.group_path());
 283         full_path.push("owner");
 284         let owner = proxmox::tools::fs::file_read_firstline(full_path)?;
 285         Ok(owner.trim_end().parse()?) // remove trailing newline
 286     }
 287
 288     /// Set the backup owner.
 289     pub fn set_owner(
 290         &self,
 291         backup_group: &BackupGroup,
 292         userid: &Userid,
 293         force: bool,
 294     ) -> Result<(), Error> {
 295         let mut path = self.base_path();
 296         path.push(backup_group.group_path());
 297         path.push("owner");
 298
 299         let mut open_options = std::fs::OpenOptions::new();
 300         open_options.write(true);
 301         open_options.truncate(true);
 302
 303         if force {
 304             open_options.create(true);
 305         } else {
 306             open_options.create_new(true);
 307         }
 308
 309         let mut file = open_options.open(&path)
 310             .map_err(|err| format_err!("unable to create owner file {:?} - {}", path, err))?;
 311
 312         writeln!(file, "{}", userid)
 313             .map_err(|err| format_err!("unable to write owner file  {:?} - {}", path, err))?;
 314
 315         Ok(())
 316     }
 317
 318     /// Create (if it does not already exists) and lock a backup group
 319     ///
 320     /// And set the owner to 'userid'. If the group already exists, it returns the
 321     /// current owner (instead of setting the owner).
 322     ///
 323     /// This also acquires an exclusive lock on the directory and returns the lock guard.
 324     pub fn create_locked_backup_group(
 325         &self,
 326         backup_group: &BackupGroup,
 327         userid: &Userid,
 328     ) -> Result<(Userid, DirLockGuard), Error> {
 329         // create intermediate path first:
 330         let base_path = self.base_path();
 331
 332         let mut full_path = base_path.clone();
 333         full_path.push(backup_group.backup_type());
 334         std::fs::create_dir_all(&full_path)?;
 335
 336         full_path.push(backup_group.backup_id());
 337
 338         // create the last component now
 339         match std::fs::create_dir(&full_path) {
 340             Ok(_) => {
 341                 let guard = lock_dir_noblock(&full_path, "backup group", "another backup is already running")?;
 342                 self.set_owner(backup_group, userid, false)?;
 343                 let owner = self.get_owner(backup_group)?; // just to be sure
 344                 Ok((owner, guard))
 345             }
 346             Err(ref err) if err.kind() == io::ErrorKind::AlreadyExists => {
 347                 let guard = lock_dir_noblock(&full_path, "backup group", "another backup is already running")?;
 348                 let owner = self.get_owner(backup_group)?; // just to be sure
 349                 Ok((owner, guard))
 350             }
 351             Err(err) => bail!("unable to create backup group {:?} - {}", full_path, err),
 352         }
 353     }
 354
 355     /// Creates a new backup snapshot inside a BackupGroup
 356     ///
 357     /// The BackupGroup directory needs to exist.
 358     pub fn create_locked_backup_dir(&self, backup_dir: &BackupDir)
 359         -> Result<(PathBuf, bool, DirLockGuard), Error>
 360     {
 361         let relative_path = backup_dir.relative_path();
 362         let mut full_path = self.base_path();
 363         full_path.push(&relative_path);
 364
 365         let lock = ||
 366             lock_dir_noblock(&full_path, "snapshot", "internal error - tried creating snapshot that's already in use");
 367
 368         match std::fs::create_dir(&full_path) {
 369             Ok(_) => Ok((relative_path, true, lock()?)),
 370             Err(ref e) if e.kind() == io::ErrorKind::AlreadyExists => Ok((relative_path, false, lock()?)),
 371             Err(e) => Err(e.into())
 372         }
 373     }
 374
 375     pub fn list_images(&self) -> Result<Vec<PathBuf>, Error> {
 376         let base = self.base_path();
 377
 378         let mut list = vec![];
 379
 380         use walkdir::WalkDir;
 381
 382         let walker = WalkDir::new(&base).same_file_system(true).into_iter();
 383
 384         // make sure we skip .chunks (and other hidden files to keep it simple)
 385         fn is_hidden(entry: &walkdir::DirEntry) -> bool {
 386             entry.file_name()
 387                 .to_str()
 388                 .map(|s| s.starts_with("."))
 389                 .unwrap_or(false)
 390         }
 391         let handle_entry_err = |err: walkdir::Error| {
 392             if let Some(inner) = err.io_error() {
 393                 let path = err.path().unwrap_or(Path::new(""));
 394                 match inner.kind() {
 395                     io::ErrorKind::PermissionDenied => {
 396                         // only allow to skip ext4 fsck directory, avoid GC if, for example,
 397                         // a user got file permissions wrong on datastore rsync to new server
 398                         if err.depth() > 1 || !path.ends_with("lost+found") {
 399                             bail!("cannot continue garbage-collection safely, permission denied on: {}", path.display())
 400                         }
 401                     },
 402                     _ => bail!("unexpected error on datastore traversal: {} - {}", inner, path.display()),
 403                 }
 404             }
 405             Ok(())
 406         };
 407         for entry in walker.filter_entry(|e| !is_hidden(e)) {
 408             let path = match entry {
 409                 Ok(entry) => entry.into_path(),
 410                 Err(err) => {
 411                     handle_entry_err(err)?;
 412                     continue
 413                 },
 414             };
 415             if let Ok(archive_type) = archive_type(&path) {
 416                 if archive_type == ArchiveType::FixedIndex || archive_type == ArchiveType::DynamicIndex {
 417                     list.push(path);
 418                 }
 419             }
 420         }
 421
 422         Ok(list)
 423     }
 424
 425     // mark chunks  used by ``index`` as used
 426     fn index_mark_used_chunks<I: IndexFile>(
 427         &self,
 428         index: I,
 429         file_name: &Path, // only used for error reporting
 430         status: &mut GarbageCollectionStatus,
 431         worker: &dyn TaskState,
 432     ) -> Result<(), Error> {
 433
 434         status.index_file_count += 1;
 435         status.index_data_bytes += index.index_bytes();
 436
 437         for pos in 0..index.index_count() {
 438             worker.check_abort()?;
 439             tools::fail_on_shutdown()?;
 440             let digest = index.index_digest(pos).unwrap();
 441             if let Err(err) = self.chunk_store.touch_chunk(digest) {
 442                 crate::task_warn!(
 443                     worker,
 444                     "warning: unable to access chunk {}, required by {:?} - {}",
 445                     proxmox::tools::digest_to_hex(digest),
 446                     file_name,
 447                     err,
 448                 );
 449             }
 450         }
 451         Ok(())
 452     }
 453
 454     fn mark_used_chunks(
 455         &self,
 456         status: &mut GarbageCollectionStatus,
 457         worker: &dyn TaskState,
 458     ) -> Result<(), Error> {
 459
 460         let image_list = self.list_images()?;
 461
 462         let image_count = image_list.len();
 463
 464         let mut done = 0;
 465
 466         let mut last_percentage: usize = 0;
 467
 468         for path in image_list {
 469
 470             worker.check_abort()?;
 471             tools::fail_on_shutdown()?;
 472
 473             let full_path = self.chunk_store.relative_path(&path);
 474             match std::fs::File::open(&full_path) {
 475                 Ok(file) => {
 476                     if let Ok(archive_type) = archive_type(&path) {
 477                         if archive_type == ArchiveType::FixedIndex {
 478                             let index = FixedIndexReader::new(file)?;
 479                             self.index_mark_used_chunks(index, &path, status, worker)?;
 480                         } else if archive_type == ArchiveType::DynamicIndex {
 481                             let index = DynamicIndexReader::new(file)?;
 482                             self.index_mark_used_chunks(index, &path, status, worker)?;
 483                         }
 484                     }
 485                 }
 486                 Err(err) => {
 487                     if err.kind() == std::io::ErrorKind::NotFound {
 488                         // simply ignore vanished files
 489                     } else {
 490                         return Err(err.into());
 491                     }
 492                 }
 493             }
 494             done += 1;
 495
 496             let percentage = done*100/image_count;
 497             if percentage > last_percentage {
 498                 crate::task_log!(
 499                     worker,
 500                     "percentage done: phase1 {}% ({} of {} index files)",
 501                     percentage,
 502                     done,
 503                     image_count,
 504                 );
 505                 last_percentage = percentage;
 506             }
 507         }
 508
 509         Ok(())
 510     }
 511
 512     pub fn last_gc_status(&self) -> GarbageCollectionStatus {
 513         self.last_gc_status.lock().unwrap().clone()
 514     }
 515
 516     pub fn garbage_collection_running(&self) -> bool {
 517         if let Ok(_) = self.gc_mutex.try_lock() { false } else { true }
 518     }
 519
 520     pub fn garbage_collection(&self, worker: &dyn TaskState, upid: &UPID) -> Result<(), Error> {
 521
 522         if let Ok(ref mut _mutex) = self.gc_mutex.try_lock() {
 523
 524             // avoids that we run GC if an old daemon process has still a
 525             // running backup writer, which is not save as we have no "oldest
 526             // writer" information and thus no safe atime cutoff
 527             let _exclusive_lock =  self.chunk_store.try_exclusive_lock()?;
 528
 529             let phase1_start_time = proxmox::tools::time::epoch_i64();
 530             let oldest_writer = self.chunk_store.oldest_writer().unwrap_or(phase1_start_time);
 531
 532             let mut gc_status = GarbageCollectionStatus::default();
 533             gc_status.upid = Some(upid.to_string());
 534
 535             crate::task_log!(worker, "Start GC phase1 (mark used chunks)");
 536
 537             self.mark_used_chunks(&mut gc_status, worker)?;
 538
 539             crate::task_log!(worker, "Start GC phase2 (sweep unused chunks)");
 540             self.chunk_store.sweep_unused_chunks(
 541                 oldest_writer,
 542                 phase1_start_time,
 543                 &mut gc_status,
 544                 worker,
 545             )?;
 546
 547             crate::task_log!(
 548                 worker,
 549                 "Removed garbage: {}",
 550                 HumanByte::from(gc_status.removed_bytes),
 551             );
 552             crate::task_log!(worker, "Removed chunks: {}", gc_status.removed_chunks);
 553             if gc_status.pending_bytes > 0 {
 554                 crate::task_log!(
 555                     worker,
 556                     "Pending removals: {} (in {} chunks)",
 557                     HumanByte::from(gc_status.pending_bytes),
 558                     gc_status.pending_chunks,
 559                 );
 560             }
 561             if gc_status.removed_bad > 0 {
 562                 crate::task_log!(worker, "Removed bad chunks: {}", gc_status.removed_bad);
 563             }
 564
 565             if gc_status.still_bad > 0 {
 566                 crate::task_log!(worker, "Leftover bad chunks: {}", gc_status.still_bad);
 567             }
 568
 569             crate::task_log!(
 570                 worker,
 571                 "Original data usage: {}",
 572                 HumanByte::from(gc_status.index_data_bytes),
 573             );
 574
 575             if gc_status.index_data_bytes > 0 {
 576                 let comp_per = (gc_status.disk_bytes as f64 * 100.)/gc_status.index_data_bytes as f64;
 577                 crate::task_log!(
 578                     worker,
 579                     "On-Disk usage: {} ({:.2}%)",
 580                     HumanByte::from(gc_status.disk_bytes),
 581                     comp_per,
 582                 );
 583             }
 584
 585             crate::task_log!(worker, "On-Disk chunks: {}", gc_status.disk_chunks);
 586
 587             let deduplication_factor = if gc_status.disk_bytes > 0 {
 588                 (gc_status.index_data_bytes as f64)/(gc_status.disk_bytes as f64)
 589             } else {
 590                 1.0
 591             };
 592
 593             crate::task_log!(worker, "Deduplication factor: {:.2}", deduplication_factor);
 594
 595             if gc_status.disk_chunks > 0 {
 596                 let avg_chunk = gc_status.disk_bytes/(gc_status.disk_chunks as u64);
 597                 crate::task_log!(worker, "Average chunk size: {}", HumanByte::from(avg_chunk));
 598             }
 599
 600             if let Ok(serialized) = serde_json::to_string(&gc_status) {
 601                 let mut path = self.base_path();
 602                 path.push(".gc-status");
 603
 604                 let backup_user = crate::backup::backup_user()?;
 605                 let mode = nix::sys::stat::Mode::from_bits_truncate(0o0644);
 606                 // set the correct owner/group/permissions while saving file
 607                 // owner(rw) = backup, group(r)= backup
 608                 let options = CreateOptions::new()
 609                     .perm(mode)
 610                     .owner(backup_user.uid)
 611                     .group(backup_user.gid);
 612
 613                 // ignore errors
 614                 let _ = replace_file(path, serialized.as_bytes(), options);
 615             }
 616
 617             *self.last_gc_status.lock().unwrap() = gc_status;
 618
 619         } else {
 620             bail!("Start GC failed - (already running/locked)");
 621         }
 622
 623         Ok(())
 624     }
 625
 626     pub fn try_shared_chunk_store_lock(&self) -> Result<tools::ProcessLockSharedGuard, Error> {
 627         self.chunk_store.try_shared_lock()
 628     }
 629
 630     pub fn chunk_path(&self, digest:&[u8; 32]) -> (PathBuf, String) {
 631         self.chunk_store.chunk_path(digest)
 632     }
 633
 634     pub fn cond_touch_chunk(&self, digest: &[u8; 32], fail_if_not_exist: bool) -> Result<bool, Error> {
 635         self.chunk_store.cond_touch_chunk(digest, fail_if_not_exist)
 636     }
 637
 638     pub fn insert_chunk(
 639         &self,
 640         chunk: &DataBlob,
 641         digest: &[u8; 32],
 642     ) -> Result<(bool, u64), Error> {
 643         self.chunk_store.insert_chunk(chunk, digest)
 644     }
 645
 646     pub fn load_blob(&self, backup_dir: &BackupDir, filename: &str) -> Result<DataBlob, Error> {
 647         let mut path = self.base_path();
 648         path.push(backup_dir.relative_path());
 649         path.push(filename);
 650
 651         proxmox::try_block!({
 652             let mut file = std::fs::File::open(&path)?;
 653             DataBlob::load_from_reader(&mut file)
 654         }).map_err(|err| format_err!("unable to load blob '{:?}' - {}", path, err))
 655     }
 656
 657
 658     pub fn load_chunk(&self, digest: &[u8; 32]) -> Result<DataBlob, Error> {
 659
 660         let (chunk_path, digest_str) = self.chunk_store.chunk_path(digest);
 661
 662         proxmox::try_block!({
 663             let mut file = std::fs::File::open(&chunk_path)?;
 664             DataBlob::load_from_reader(&mut file)
 665         }).map_err(|err| format_err!(
 666             "store '{}', unable to load chunk '{}' - {}",
 667             self.name(),
 668             digest_str,
 669             err,
 670         ))
 671     }
 672
 673     fn lock_manifest(
 674         &self,
 675         backup_dir: &BackupDir,
 676     ) -> Result<File, Error> {
 677         let mut path = self.base_path();
 678         path.push(backup_dir.relative_path());
 679         path.push(&MANIFEST_LOCK_NAME);
 680
 681         // update_manifest should never take a long time, so if someone else has
 682         // the lock we can simply block a bit and should get it soon
 683         open_file_locked(&path, Duration::from_secs(5), true)
 684             .map_err(|err| {
 685                 format_err!(
 686                     "unable to acquire manifest lock {:?} - {}", &path, err
 687                 )
 688             })
 689     }
 690
 691     /// Load the manifest without a lock. Must not be written back.
 692     pub fn load_manifest(
 693         &self,
 694         backup_dir: &BackupDir,
 695     ) -> Result<(BackupManifest, u64), Error> {
 696         let blob = self.load_blob(backup_dir, MANIFEST_BLOB_NAME)?;
 697         let raw_size = blob.raw_size();
 698         let manifest = BackupManifest::try_from(blob)?;
 699         Ok((manifest, raw_size))
 700     }
 701
 702     /// Update the manifest of the specified snapshot. Never write a manifest directly,
 703     /// only use this method - anything else may break locking guarantees.
 704     pub fn update_manifest(
 705         &self,
 706         backup_dir: &BackupDir,
 707         update_fn: impl FnOnce(&mut BackupManifest),
 708     ) -> Result<(), Error> {
 709
 710         let _guard = self.lock_manifest(backup_dir)?;
 711         let (mut manifest, _) = self.load_manifest(&backup_dir)?;
 712
 713         update_fn(&mut manifest);
 714
 715         let manifest = serde_json::to_value(manifest)?;
 716         let manifest = serde_json::to_string_pretty(&manifest)?;
 717         let blob = DataBlob::encode(manifest.as_bytes(), None, true)?;
 718         let raw_data = blob.raw_data();
 719
 720         let mut path = self.base_path();
 721         path.push(backup_dir.relative_path());
 722         path.push(MANIFEST_BLOB_NAME);
 723
 724         // atomic replace invalidates flock - no other writes past this point!
 725         replace_file(&path, raw_data, CreateOptions::new())?;
 726
 727         Ok(())
 728     }
 729
 730     pub fn verify_new(&self) -> bool {
 731         self.verify_new
 732     }
 733 }