package index import ( "bytes" "context" "fmt" "runtime" "sync" "github.com/restic/restic/internal/debug" "github.com/restic/restic/internal/restic" "github.com/restic/restic/internal/ui/progress" "golang.org/x/sync/errgroup" ) // MasterIndex is a collection of indexes and IDs of chunks that are in the process of being saved. type MasterIndex struct { idx []*Index pendingBlobs restic.BlobSet idxMutex sync.RWMutex compress bool } // NewMasterIndex creates a new master index. func NewMasterIndex() *MasterIndex { // Always add an empty final index, such that MergeFinalIndexes can merge into this. // Note that removing this index could lead to a race condition in the rare // sitation that only two indexes exist which are saved and merged concurrently. idx := []*Index{NewIndex()} idx[0].Finalize() return &MasterIndex{idx: idx, pendingBlobs: restic.NewBlobSet()} } func (mi *MasterIndex) MarkCompressed() { mi.compress = true } // Lookup queries all known Indexes for the ID and returns all matches. func (mi *MasterIndex) Lookup(bh restic.BlobHandle) (pbs []restic.PackedBlob) { mi.idxMutex.RLock() defer mi.idxMutex.RUnlock() for _, idx := range mi.idx { pbs = idx.Lookup(bh, pbs) } return pbs } // LookupSize queries all known Indexes for the ID and returns the first match. func (mi *MasterIndex) LookupSize(bh restic.BlobHandle) (uint, bool) { mi.idxMutex.RLock() defer mi.idxMutex.RUnlock() for _, idx := range mi.idx { if size, found := idx.LookupSize(bh); found { return size, found } } return 0, false } // AddPending adds a given blob to list of pending Blobs // Before doing so it checks if this blob is already known. // Returns true if adding was successful and false if the blob // was already known func (mi *MasterIndex) AddPending(bh restic.BlobHandle) bool { mi.idxMutex.Lock() defer mi.idxMutex.Unlock() // Check if blob is pending or in index if mi.pendingBlobs.Has(bh) { return false } for _, idx := range mi.idx { if idx.Has(bh) { return false } } // really not known -> insert mi.pendingBlobs.Insert(bh) return true } // Has queries all known Indexes for the ID and returns the first match. // Also returns true if the ID is pending. func (mi *MasterIndex) Has(bh restic.BlobHandle) bool { mi.idxMutex.RLock() defer mi.idxMutex.RUnlock() // also return true if blob is pending if mi.pendingBlobs.Has(bh) { return true } for _, idx := range mi.idx { if idx.Has(bh) { return true } } return false } // IDs returns the IDs of all indexes contained in the index. func (mi *MasterIndex) IDs() restic.IDSet { mi.idxMutex.RLock() defer mi.idxMutex.RUnlock() ids := restic.NewIDSet() for _, idx := range mi.idx { if !idx.Final() { continue } indexIDs, err := idx.IDs() if err != nil { debug.Log("not using index, ID() returned error %v", err) continue } for _, id := range indexIDs { ids.Insert(id) } } return ids } // Packs returns all packs that are covered by the index. // If packBlacklist is given, those packs are only contained in the // resulting IDSet if they are contained in a non-final (newly written) index. func (mi *MasterIndex) Packs(packBlacklist restic.IDSet) restic.IDSet { mi.idxMutex.RLock() defer mi.idxMutex.RUnlock() packs := restic.NewIDSet() for _, idx := range mi.idx { idxPacks := idx.Packs() if idx.final && len(packBlacklist) > 0 { idxPacks = idxPacks.Sub(packBlacklist) } packs.Merge(idxPacks) } return packs } // Insert adds a new index to the MasterIndex. func (mi *MasterIndex) Insert(idx *Index) { mi.idxMutex.Lock() defer mi.idxMutex.Unlock() mi.idx = append(mi.idx, idx) } // StorePack remembers the id and pack in the index. func (mi *MasterIndex) StorePack(id restic.ID, blobs []restic.Blob) { mi.idxMutex.Lock() defer mi.idxMutex.Unlock() // delete blobs from pending for _, blob := range blobs { mi.pendingBlobs.Delete(restic.BlobHandle{Type: blob.Type, ID: blob.ID}) } for _, idx := range mi.idx { if !idx.Final() { idx.StorePack(id, blobs) return } } newIdx := NewIndex() newIdx.StorePack(id, blobs) mi.idx = append(mi.idx, newIdx) } // finalizeNotFinalIndexes finalizes all indexes that // have not yet been saved and returns that list func (mi *MasterIndex) finalizeNotFinalIndexes() []*Index { mi.idxMutex.Lock() defer mi.idxMutex.Unlock() var list []*Index for _, idx := range mi.idx { if !idx.Final() { idx.Finalize() list = append(list, idx) } } debug.Log("return %d indexes", len(list)) return list } // finalizeFullIndexes finalizes all indexes that are full and returns that list. func (mi *MasterIndex) finalizeFullIndexes() []*Index { mi.idxMutex.Lock() defer mi.idxMutex.Unlock() var list []*Index debug.Log("checking %d indexes", len(mi.idx)) for _, idx := range mi.idx { if idx.Final() { continue } if IndexFull(idx, mi.compress) { debug.Log("index %p is full", idx) idx.Finalize() list = append(list, idx) } else { debug.Log("index %p not full", idx) } } debug.Log("return %d indexes", len(list)) return list } // Each runs fn on all blobs known to the index. When the context is cancelled, // the index iteration return immediately. This blocks any modification of the index. func (mi *MasterIndex) Each(ctx context.Context, fn func(restic.PackedBlob)) { mi.idxMutex.RLock() defer mi.idxMutex.RUnlock() for _, idx := range mi.idx { idx.Each(ctx, fn) } } // MergeFinalIndexes merges all final indexes together. // After calling, there will be only one big final index in MasterIndex // containing all final index contents. // Indexes that are not final are left untouched. // This merging can only be called after all index files are loaded - as // removing of superseded index contents is only possible for unmerged indexes. func (mi *MasterIndex) MergeFinalIndexes() error { mi.idxMutex.Lock() defer mi.idxMutex.Unlock() // The first index is always final and the one to merge into newIdx := mi.idx[:1] for i := 1; i < len(mi.idx); i++ { idx := mi.idx[i] // clear reference in masterindex as it may become stale mi.idx[i] = nil // do not merge indexes that have no id set ids, _ := idx.IDs() if !idx.Final() || len(ids) == 0 { newIdx = append(newIdx, idx) } else { err := mi.idx[0].merge(idx) if err != nil { return fmt.Errorf("MergeFinalIndexes: %w", err) } } } mi.idx = newIdx return nil } // Save saves all known indexes to index files, leaving out any // packs whose ID is contained in packBlacklist from finalized indexes. // The new index contains the IDs of all known indexes in the "supersedes" // field. The IDs are also returned in the IDSet obsolete. // After calling this function, you should remove the obsolete index files. func (mi *MasterIndex) Save(ctx context.Context, repo restic.SaverUnpacked, packBlacklist restic.IDSet, extraObsolete restic.IDs, p *progress.Counter) (obsolete restic.IDSet, err error) { p.SetMax(uint64(len(mi.Packs(packBlacklist)))) mi.idxMutex.Lock() defer mi.idxMutex.Unlock() debug.Log("start rebuilding index of %d indexes, pack blacklist: %v", len(mi.idx), packBlacklist) newIndex := NewIndex() obsolete = restic.NewIDSet() // track spawned goroutines using wg, create a new context which is // cancelled as soon as an error occurs. wg, ctx := errgroup.WithContext(ctx) ch := make(chan *Index) wg.Go(func() error { defer close(ch) for i, idx := range mi.idx { if idx.Final() { ids, err := idx.IDs() if err != nil { debug.Log("index %d does not have an ID: %v", err) return err } debug.Log("adding index ids %v to supersedes field", ids) err = newIndex.AddToSupersedes(ids...) if err != nil { return err } obsolete.Merge(restic.NewIDSet(ids...)) } else { debug.Log("index %d isn't final, don't add to supersedes field", i) } debug.Log("adding index %d", i) for pbs := range idx.EachByPack(ctx, packBlacklist) { newIndex.StorePack(pbs.PackID, pbs.Blobs) p.Add(1) if IndexFull(newIndex, mi.compress) { select { case ch <- newIndex: case <-ctx.Done(): return ctx.Err() } newIndex = NewIndex() } } } err = newIndex.AddToSupersedes(extraObsolete...) if err != nil { return err } obsolete.Merge(restic.NewIDSet(extraObsolete...)) select { case ch <- newIndex: case <-ctx.Done(): } return nil }) // a worker receives an index from ch, and saves the index worker := func() error { for idx := range ch { idx.Finalize() if _, err := SaveIndex(ctx, repo, idx); err != nil { return err } } return nil } // encoding an index can take quite some time such that this can be both CPU- or IO-bound workerCount := int(repo.Connections()) + runtime.GOMAXPROCS(0) // run workers on ch for i := 0; i < workerCount; i++ { wg.Go(worker) } err = wg.Wait() return obsolete, err } // SaveIndex saves an index in the repository. func SaveIndex(ctx context.Context, repo restic.SaverUnpacked, index *Index) (restic.ID, error) { buf := bytes.NewBuffer(nil) err := index.Encode(buf) if err != nil { return restic.ID{}, err } id, err := repo.SaveUnpacked(ctx, restic.IndexFile, buf.Bytes()) ierr := index.SetID(id) if ierr != nil { // logic bug panic(ierr) } return id, err } // saveIndex saves all indexes in the backend. func (mi *MasterIndex) saveIndex(ctx context.Context, r restic.SaverUnpacked, indexes ...*Index) error { for i, idx := range indexes { debug.Log("Saving index %d", i) sid, err := SaveIndex(ctx, r, idx) if err != nil { return err } debug.Log("Saved index %d as %v", i, sid) } return mi.MergeFinalIndexes() } // SaveIndex saves all new indexes in the backend. func (mi *MasterIndex) SaveIndex(ctx context.Context, r restic.SaverUnpacked) error { return mi.saveIndex(ctx, r, mi.finalizeNotFinalIndexes()...) } // SaveFullIndex saves all full indexes in the backend. func (mi *MasterIndex) SaveFullIndex(ctx context.Context, r restic.SaverUnpacked) error { return mi.saveIndex(ctx, r, mi.finalizeFullIndexes()...) } // ListPacks returns the blobs of the specified pack files grouped by pack file. func (mi *MasterIndex) ListPacks(ctx context.Context, packs restic.IDSet) <-chan restic.PackBlobs { out := make(chan restic.PackBlobs) go func() { defer close(out) // only resort a part of the index to keep the memory overhead bounded for i := byte(0); i < 16; i++ { if ctx.Err() != nil { return } packBlob := make(map[restic.ID][]restic.Blob) for pack := range packs { if pack[0]&0xf == i { packBlob[pack] = nil } } if len(packBlob) == 0 { continue } mi.Each(ctx, func(pb restic.PackedBlob) { if packs.Has(pb.PackID) && pb.PackID[0]&0xf == i { packBlob[pb.PackID] = append(packBlob[pb.PackID], pb.Blob) } }) // pass on packs for packID, pbs := range packBlob { // allow GC packBlob[packID] = nil select { case out <- restic.PackBlobs{PackID: packID, Blobs: pbs}: case <-ctx.Done(): return } } } }() return out }