restic/internal/checker/checker.go

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package checker
import (
"bufio"
"bytes"
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"context"
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"fmt"
"io"
"runtime"
"sort"
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"sync"
"github.com/klauspost/compress/zstd"
"github.com/minio/sha256-simd"
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"github.com/restic/restic/internal/backend"
"github.com/restic/restic/internal/backend/s3"
"github.com/restic/restic/internal/cache"
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"github.com/restic/restic/internal/debug"
"github.com/restic/restic/internal/errors"
"github.com/restic/restic/internal/hashing"
"github.com/restic/restic/internal/index"
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"github.com/restic/restic/internal/pack"
"github.com/restic/restic/internal/repository"
"github.com/restic/restic/internal/restic"
"github.com/restic/restic/internal/ui/progress"
"golang.org/x/sync/errgroup"
)
// Checker runs various checks on a repository. It is advisable to create an
// exclusive Lock in the repository before running any checks.
//
// A Checker only tests for internal errors within the data structures of the
// repository (e.g. missing blobs), and needs a valid Repository to work on.
type Checker struct {
packs map[restic.ID]int64
blobRefs struct {
sync.Mutex
M restic.BlobSet
}
trackUnused bool
masterIndex *index.MasterIndex
snapshots restic.Lister
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repo restic.Repository
}
// New returns a new checker which runs on repo.
func New(repo restic.Repository, trackUnused bool) *Checker {
c := &Checker{
packs: make(map[restic.ID]int64),
masterIndex: index.NewMasterIndex(),
repo: repo,
trackUnused: trackUnused,
}
c.blobRefs.M = restic.NewBlobSet()
return c
}
// ErrLegacyLayout is returned when the repository uses the S3 legacy layout.
var ErrLegacyLayout = errors.New("repository uses S3 legacy layout")
// ErrDuplicatePacks is returned when a pack is found in more than one index.
type ErrDuplicatePacks struct {
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PackID restic.ID
Indexes restic.IDSet
}
func (e *ErrDuplicatePacks) Error() string {
return fmt.Sprintf("pack %v contained in several indexes: %v", e.PackID, e.Indexes)
}
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// ErrMixedPack is returned when a pack is found that contains both tree and data blobs.
type ErrMixedPack struct {
PackID restic.ID
}
func (e *ErrMixedPack) Error() string {
return fmt.Sprintf("pack %v contains a mix of tree and data blobs", e.PackID.Str())
}
// ErrOldIndexFormat is returned when an index with the old format is
// found.
type ErrOldIndexFormat struct {
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restic.ID
}
func (err *ErrOldIndexFormat) Error() string {
return fmt.Sprintf("index %v has old format", err.ID)
}
// ErrPackData is returned if errors are discovered while verifying a packfile
type ErrPackData struct {
PackID restic.ID
errs []error
}
func (e *ErrPackData) Error() string {
return fmt.Sprintf("pack %v contains %v errors: %v", e.PackID, len(e.errs), e.errs)
}
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func (c *Checker) LoadSnapshots(ctx context.Context) error {
var err error
c.snapshots, err = restic.MemorizeList(ctx, c.repo, restic.SnapshotFile)
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return err
}
func computePackTypes(ctx context.Context, idx restic.MasterIndex) map[restic.ID]restic.BlobType {
packs := make(map[restic.ID]restic.BlobType)
idx.Each(ctx, func(pb restic.PackedBlob) {
tpe, exists := packs[pb.PackID]
if exists {
if pb.Type != tpe {
tpe = restic.InvalidBlob
}
} else {
tpe = pb.Type
}
packs[pb.PackID] = tpe
})
return packs
}
// LoadIndex loads all index files.
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func (c *Checker) LoadIndex(ctx context.Context, p *progress.Counter) (hints []error, errs []error) {
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debug.Log("Start")
indexList, err := restic.MemorizeList(ctx, c.repo, restic.IndexFile)
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if err != nil {
// abort if an error occurs while listing the indexes
return hints, append(errs, err)
}
if p != nil {
var numIndexFiles uint64
err := indexList.List(ctx, restic.IndexFile, func(id restic.ID, size int64) error {
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numIndexFiles++
return nil
})
if err != nil {
return hints, append(errs, err)
}
p.SetMax(numIndexFiles)
defer p.Done()
}
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packToIndex := make(map[restic.ID]restic.IDSet)
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err = index.ForAllIndexes(ctx, indexList, c.repo, func(id restic.ID, index *index.Index, oldFormat bool, err error) error {
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debug.Log("process index %v, err %v", id, err)
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if p != nil {
p.Add(1)
}
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if oldFormat {
debug.Log("index %v has old format", id)
hints = append(hints, &ErrOldIndexFormat{id})
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}
err = errors.Wrapf(err, "error loading index %v", id)
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if err != nil {
errs = append(errs, err)
return nil
}
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c.masterIndex.Insert(index)
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debug.Log("process blobs")
cnt := 0
index.Each(ctx, func(blob restic.PackedBlob) {
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cnt++
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if _, ok := packToIndex[blob.PackID]; !ok {
packToIndex[blob.PackID] = restic.NewIDSet()
}
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packToIndex[blob.PackID].Insert(id)
})
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debug.Log("%d blobs processed", cnt)
return nil
})
if err != nil {
errs = append(errs, err)
}
// Merge index before computing pack sizes, as this needs removed duplicates
err = c.masterIndex.MergeFinalIndexes()
if err != nil {
// abort if an error occurs merging the indexes
return hints, append(errs, err)
}
// compute pack size using index entries
c.packs = pack.Size(ctx, c.masterIndex, false)
packTypes := computePackTypes(ctx, c.masterIndex)
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debug.Log("checking for duplicate packs")
for packID := range c.packs {
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debug.Log(" check pack %v: contained in %d indexes", packID, len(packToIndex[packID]))
if len(packToIndex[packID]) > 1 {
hints = append(hints, &ErrDuplicatePacks{
PackID: packID,
Indexes: packToIndex[packID],
})
}
if packTypes[packID] == restic.InvalidBlob {
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hints = append(hints, &ErrMixedPack{
PackID: packID,
})
}
}
err = c.repo.SetIndex(c.masterIndex)
if err != nil {
debug.Log("SetIndex returned error: %v", err)
errs = append(errs, err)
}
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return hints, errs
}
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// PackError describes an error with a specific pack.
type PackError struct {
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ID restic.ID
Orphaned bool
Err error
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}
func (e *PackError) Error() string {
return "pack " + e.ID.String() + ": " + e.Err.Error()
}
// IsOrphanedPack returns true if the error describes a pack which is not
// contained in any index.
func IsOrphanedPack(err error) bool {
var e *PackError
return errors.As(err, &e) && e.Orphaned
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}
func isS3Legacy(b backend.Backend) bool {
// unwrap cache
if be, ok := b.(*cache.Backend); ok {
b = be.Backend
}
be, ok := b.(*s3.Backend)
if !ok {
return false
}
return be.Layout.Name() == "s3legacy"
}
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// Packs checks that all packs referenced in the index are still available and
// there are no packs that aren't in an index. errChan is closed after all
// packs have been checked.
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func (c *Checker) Packs(ctx context.Context, errChan chan<- error) {
defer close(errChan)
if isS3Legacy(c.repo.Backend()) {
errChan <- ErrLegacyLayout
}
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debug.Log("checking for %d packs", len(c.packs))
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debug.Log("listing repository packs")
repoPacks := make(map[restic.ID]int64)
err := c.repo.List(ctx, restic.PackFile, func(id restic.ID, size int64) error {
repoPacks[id] = size
return nil
})
if err != nil {
errChan <- err
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}
for id, size := range c.packs {
reposize, ok := repoPacks[id]
// remove from repoPacks so we can find orphaned packs
delete(repoPacks, id)
// missing: present in c.packs but not in the repo
if !ok {
select {
case <-ctx.Done():
return
case errChan <- &PackError{ID: id, Err: errors.New("does not exist")}:
}
continue
}
// size not matching: present in c.packs and in the repo, but sizes do not match
if size != reposize {
select {
case <-ctx.Done():
return
case errChan <- &PackError{ID: id, Err: errors.Errorf("unexpected file size: got %d, expected %d", reposize, size)}:
}
}
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}
// orphaned: present in the repo but not in c.packs
for orphanID := range repoPacks {
select {
case <-ctx.Done():
return
case errChan <- &PackError{ID: orphanID, Orphaned: true, Err: errors.New("not referenced in any index")}:
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}
}
}
// Error is an error that occurred while checking a repository.
type Error struct {
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TreeID restic.ID
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Err error
}
func (e *Error) Error() string {
if !e.TreeID.IsNull() {
return "tree " + e.TreeID.String() + ": " + e.Err.Error()
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}
return e.Err.Error()
}
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// TreeError collects several errors that occurred while processing a tree.
type TreeError struct {
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ID restic.ID
Errors []error
}
func (e *TreeError) Error() string {
return fmt.Sprintf("tree %v: %v", e.ID, e.Errors)
}
// checkTreeWorker checks the trees received and sends out errors to errChan.
func (c *Checker) checkTreeWorker(ctx context.Context, trees <-chan restic.TreeItem, out chan<- error) {
for job := range trees {
debug.Log("check tree %v (tree %v, err %v)", job.ID, job.Tree, job.Error)
var errs []error
if job.Error != nil {
errs = append(errs, job.Error)
} else {
errs = c.checkTree(job.ID, job.Tree)
}
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if len(errs) == 0 {
continue
}
treeError := &TreeError{ID: job.ID, Errors: errs}
select {
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case <-ctx.Done():
return
case out <- treeError:
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debug.Log("tree %v: sent %d errors", treeError.ID, len(treeError.Errors))
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}
}
}
func loadSnapshotTreeIDs(ctx context.Context, lister restic.Lister, repo restic.Repository) (ids restic.IDs, errs []error) {
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err := restic.ForAllSnapshots(ctx, lister, repo, nil, func(id restic.ID, sn *restic.Snapshot, err error) error {
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if err != nil {
errs = append(errs, err)
return nil
}
treeID := *sn.Tree
debug.Log("snapshot %v has tree %v", id, treeID)
ids = append(ids, treeID)
return nil
})
if err != nil {
errs = append(errs, err)
}
return ids, errs
}
// Structure checks that for all snapshots all referenced data blobs and
// subtrees are available in the index. errChan is closed after all trees have
// been traversed.
func (c *Checker) Structure(ctx context.Context, p *progress.Counter, errChan chan<- error) {
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trees, errs := loadSnapshotTreeIDs(ctx, c.snapshots, c.repo)
p.SetMax(uint64(len(trees)))
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debug.Log("need to check %d trees from snapshots, %d errs returned", len(trees), len(errs))
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for _, err := range errs {
select {
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case <-ctx.Done():
return
case errChan <- err:
}
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}
wg, ctx := errgroup.WithContext(ctx)
treeStream := restic.StreamTrees(ctx, wg, c.repo, trees, func(treeID restic.ID) bool {
// blobRefs may be accessed in parallel by checkTree
c.blobRefs.Lock()
h := restic.BlobHandle{ID: treeID, Type: restic.TreeBlob}
blobReferenced := c.blobRefs.M.Has(h)
// noop if already referenced
c.blobRefs.M.Insert(h)
c.blobRefs.Unlock()
return blobReferenced
}, p)
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defer close(errChan)
// The checkTree worker only processes already decoded trees and is thus CPU-bound
workerCount := runtime.GOMAXPROCS(0)
for i := 0; i < workerCount; i++ {
wg.Go(func() error {
c.checkTreeWorker(ctx, treeStream, errChan)
return nil
})
}
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// the wait group should not return an error because no worker returns an
// error, so panic if that has changed somehow.
err := wg.Wait()
if err != nil {
panic(err)
}
}
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func (c *Checker) checkTree(id restic.ID, tree *restic.Tree) (errs []error) {
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debug.Log("checking tree %v", id)
for _, node := range tree.Nodes {
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switch node.Type {
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case "file":
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if node.Content == nil {
errs = append(errs, &Error{TreeID: id, Err: errors.Errorf("file %q has nil blob list", node.Name)})
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}
for b, blobID := range node.Content {
if blobID.IsNull() {
errs = append(errs, &Error{TreeID: id, Err: errors.Errorf("file %q blob %d has null ID", node.Name, b)})
continue
}
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// Note that we do not use the blob size. The "obvious" check
// whether the sum of the blob sizes matches the file size
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// unfortunately fails in some cases that are not resolvable
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// by users, so we omit this check, see #1887
_, found := c.repo.LookupBlobSize(blobID, restic.DataBlob)
if !found {
debug.Log("tree %v references blob %v which isn't contained in index", id, blobID)
errs = append(errs, &Error{TreeID: id, Err: errors.Errorf("file %q blob %v not found in index", node.Name, blobID)})
}
}
if c.trackUnused {
// loop a second time to keep the locked section as short as possible
c.blobRefs.Lock()
for _, blobID := range node.Content {
if blobID.IsNull() {
continue
}
h := restic.BlobHandle{ID: blobID, Type: restic.DataBlob}
c.blobRefs.M.Insert(h)
debug.Log("blob %v is referenced", blobID)
}
c.blobRefs.Unlock()
}
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case "dir":
if node.Subtree == nil {
errs = append(errs, &Error{TreeID: id, Err: errors.Errorf("dir node %q has no subtree", node.Name)})
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continue
}
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if node.Subtree.IsNull() {
errs = append(errs, &Error{TreeID: id, Err: errors.Errorf("dir node %q subtree id is null", node.Name)})
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continue
}
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case "symlink", "socket", "chardev", "dev", "fifo":
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// nothing to check
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default:
errs = append(errs, &Error{TreeID: id, Err: errors.Errorf("node %q with invalid type %q", node.Name, node.Type)})
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}
if node.Name == "" {
errs = append(errs, &Error{TreeID: id, Err: errors.New("node with empty name")})
}
}
return errs
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}
// UnusedBlobs returns all blobs that have never been referenced.
func (c *Checker) UnusedBlobs(ctx context.Context) (blobs restic.BlobHandles) {
if !c.trackUnused {
panic("only works when tracking blob references")
}
c.blobRefs.Lock()
defer c.blobRefs.Unlock()
debug.Log("checking %d blobs", len(c.blobRefs.M))
ctx, cancel := context.WithCancel(ctx)
defer cancel()
c.repo.Index().Each(ctx, func(blob restic.PackedBlob) {
h := restic.BlobHandle{ID: blob.ID, Type: blob.Type}
if !c.blobRefs.M.Has(h) {
debug.Log("blob %v not referenced", h)
blobs = append(blobs, h)
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}
})
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return blobs
}
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// CountPacks returns the number of packs in the repository.
func (c *Checker) CountPacks() uint64 {
return uint64(len(c.packs))
}
// GetPacks returns IDSet of packs in the repository
func (c *Checker) GetPacks() map[restic.ID]int64 {
return c.packs
}
// checkPack reads a pack and checks the integrity of all blobs.
func checkPack(ctx context.Context, r restic.Repository, id restic.ID, blobs []restic.Blob, size int64, bufRd *bufio.Reader, dec *zstd.Decoder) error {
debug.Log("checking pack %v", id.String())
if len(blobs) == 0 {
return errors.Errorf("pack %v is empty or not indexed", id)
}
// sanity check blobs in index
sort.Slice(blobs, func(i, j int) bool {
return blobs[i].Offset < blobs[j].Offset
})
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idxHdrSize := pack.CalculateHeaderSize(blobs)
lastBlobEnd := 0
nonContinuousPack := false
for _, blob := range blobs {
if lastBlobEnd != int(blob.Offset) {
nonContinuousPack = true
}
lastBlobEnd = int(blob.Offset + blob.Length)
}
// size was calculated by masterindex.PackSize, thus there's no need to recalculate it here
var errs []error
if nonContinuousPack {
debug.Log("Index for pack contains gaps / overlaps, blobs: %v", blobs)
errs = append(errs, errors.New("Index for pack contains gaps / overlapping blobs"))
}
// calculate hash on-the-fly while reading the pack and capture pack header
var hash restic.ID
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var hdrBuf []byte
h := backend.Handle{Type: backend.PackFile, Name: id.String()}
err := r.Backend().Load(ctx, h, int(size), 0, func(rd io.Reader) error {
hrd := hashing.NewReader(rd, sha256.New())
bufRd.Reset(hrd)
it := repository.NewPackBlobIterator(id, bufRd, 0, blobs, r.Key(), dec)
for {
val, err := it.Next()
if err == repository.ErrPackEOF {
break
} else if err != nil {
return err
}
debug.Log(" check blob %v: %v", val.Handle.ID, val.Handle)
if val.Err != nil {
debug.Log(" error verifying blob %v: %v", val.Handle.ID, err)
errs = append(errs, errors.Errorf("blob %v: %v", val.Handle.ID, err))
}
}
// skip enough bytes until we reach the possible header start
curPos := lastBlobEnd
minHdrStart := int(size) - pack.MaxHeaderSize
if minHdrStart > curPos {
_, err := bufRd.Discard(minHdrStart - curPos)
if err != nil {
return err
}
}
// read remainder, which should be the pack header
var err error
hdrBuf, err = io.ReadAll(bufRd)
if err != nil {
return err
}
hash = restic.IDFromHash(hrd.Sum(nil))
return nil
})
if err != nil {
// failed to load the pack file, return as further checks cannot succeed anyways
debug.Log(" error streaming pack: %v", err)
return errors.Errorf("pack %v failed to download: %v", id, err)
}
if !hash.Equal(id) {
debug.Log("Pack ID does not match, want %v, got %v", id, hash)
return errors.Errorf("Pack ID does not match, want %v, got %v", id, hash)
}
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blobs, hdrSize, err := pack.List(r.Key(), bytes.NewReader(hdrBuf), int64(len(hdrBuf)))
if err != nil {
return err
}
if uint32(idxHdrSize) != hdrSize {
debug.Log("Pack header size does not match, want %v, got %v", idxHdrSize, hdrSize)
errs = append(errs, errors.Errorf("Pack header size does not match, want %v, got %v", idxHdrSize, hdrSize))
}
idx := r.Index()
for _, blob := range blobs {
// Check if blob is contained in index and position is correct
idxHas := false
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for _, pb := range idx.Lookup(blob.BlobHandle) {
if pb.PackID == id && pb.Blob == blob {
idxHas = true
break
}
}
if !idxHas {
errs = append(errs, errors.Errorf("Blob %v is not contained in index or position is incorrect", blob.ID))
continue
}
}
if len(errs) > 0 {
return &ErrPackData{PackID: id, errs: errs}
}
return nil
}
// ReadData loads all data from the repository and checks the integrity.
func (c *Checker) ReadData(ctx context.Context, errChan chan<- error) {
c.ReadPacks(ctx, c.packs, nil, errChan)
}
// ReadPacks loads data from specified packs and checks the integrity.
func (c *Checker) ReadPacks(ctx context.Context, packs map[restic.ID]int64, p *progress.Counter, errChan chan<- error) {
defer close(errChan)
g, ctx := errgroup.WithContext(ctx)
type checkTask struct {
id restic.ID
size int64
blobs []restic.Blob
}
ch := make(chan checkTask)
// as packs are streamed the concurrency is limited by IO
workerCount := int(c.repo.Connections())
// run workers
for i := 0; i < workerCount; i++ {
g.Go(func() error {
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// create a buffer that is large enough to be reused by repository.StreamPack
// this ensures that we can read the pack header later on
bufRd := bufio.NewReaderSize(nil, repository.MaxStreamBufferSize)
dec, err := zstd.NewReader(nil)
if err != nil {
panic(dec)
}
defer dec.Close()
for {
var ps checkTask
var ok bool
select {
case <-ctx.Done():
return nil
case ps, ok = <-ch:
if !ok {
return nil
}
}
err := checkPack(ctx, c.repo, ps.id, ps.blobs, ps.size, bufRd, dec)
p.Add(1)
if err == nil {
continue
}
select {
case <-ctx.Done():
return nil
case errChan <- err:
}
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}
})
}
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packSet := restic.NewIDSet()
for pack := range packs {
packSet.Insert(pack)
}
// push packs to ch
for pbs := range c.repo.Index().ListPacks(ctx, packSet) {
size := packs[pbs.PackID]
debug.Log("listed %v", pbs.PackID)
select {
case ch <- checkTask{id: pbs.PackID, size: size, blobs: pbs.Blobs}:
case <-ctx.Done():
}
}
close(ch)
err := g.Wait()
if err != nil {
select {
case <-ctx.Done():
return
case errChan <- err:
}
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}
}