restic/checker/checker.go

637 lines
16 KiB
Go

package checker
import (
"errors"
"fmt"
"sync"
"github.com/restic/restic"
"github.com/restic/restic/backend"
"github.com/restic/restic/debug"
"github.com/restic/restic/repository"
)
// 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[backend.ID]struct{}
blobs map[backend.ID]struct{}
blobRefs struct {
sync.Mutex
M map[backend.ID]uint
}
indexes map[backend.ID]*repository.Index
orphanedPacks backend.IDs
masterIndex *repository.MasterIndex
repo *repository.Repository
}
// New returns a new checker which runs on repo.
func New(repo *repository.Repository) *Checker {
c := &Checker{
packs: make(map[backend.ID]struct{}),
blobs: make(map[backend.ID]struct{}),
masterIndex: repository.NewMasterIndex(),
indexes: make(map[backend.ID]*repository.Index),
repo: repo,
}
c.blobRefs.M = make(map[backend.ID]uint)
return c
}
const defaultParallelism = 40
// ErrDuplicatePacks is returned when a pack is found in more than one index.
type ErrDuplicatePacks struct {
PackID backend.ID
Indexes backend.IDSet
}
func (e ErrDuplicatePacks) Error() string {
return fmt.Sprintf("pack %v contained in several indexes: %v", e.PackID.Str(), e.Indexes)
}
// ErrOldIndexFormat is returned when an index with the old format is
// found.
type ErrOldIndexFormat struct {
backend.ID
}
func (err ErrOldIndexFormat) Error() string {
return fmt.Sprintf("index %v has old format", err.ID.Str())
}
// LoadIndex loads all index files.
func (c *Checker) LoadIndex() (hints []error, errs []error) {
debug.Log("LoadIndex", "Start")
type indexRes struct {
Index *repository.Index
ID string
}
indexCh := make(chan indexRes)
worker := func(id backend.ID, done <-chan struct{}) error {
debug.Log("LoadIndex", "worker got index %v", id)
idx, err := repository.LoadIndexWithDecoder(c.repo, id.String(), repository.DecodeIndex)
if err == repository.ErrOldIndexFormat {
debug.Log("LoadIndex", "index %v has old format", id.Str())
hints = append(hints, ErrOldIndexFormat{id})
idx, err = repository.LoadIndexWithDecoder(c.repo, id.String(), repository.DecodeOldIndex)
}
if err != nil {
return err
}
select {
case indexCh <- indexRes{Index: idx, ID: id.String()}:
case <-done:
}
return nil
}
var perr error
go func() {
defer close(indexCh)
debug.Log("LoadIndex", "start loading indexes in parallel")
perr = repository.FilesInParallel(c.repo.Backend(), backend.Index, defaultParallelism,
repository.ParallelWorkFuncParseID(worker))
debug.Log("LoadIndex", "loading indexes finished, error: %v", perr)
}()
done := make(chan struct{})
defer close(done)
if perr != nil {
errs = append(errs, perr)
return hints, errs
}
packToIndex := make(map[backend.ID]backend.IDSet)
for res := range indexCh {
debug.Log("LoadIndex", "process index %v", res.ID)
idxID, err := backend.ParseID(res.ID)
if err != nil {
errs = append(errs, fmt.Errorf("unable to parse as index ID: %v", res.ID))
continue
}
c.indexes[idxID] = res.Index
c.masterIndex.Insert(res.Index)
debug.Log("LoadIndex", "process blobs")
cnt := 0
for blob := range res.Index.Each(done) {
c.packs[blob.PackID] = struct{}{}
c.blobs[blob.ID] = struct{}{}
c.blobRefs.M[blob.ID] = 0
cnt++
if _, ok := packToIndex[blob.PackID]; !ok {
packToIndex[blob.PackID] = backend.NewIDSet()
}
packToIndex[blob.PackID].Insert(idxID)
}
debug.Log("LoadIndex", "%d blobs processed", cnt)
}
debug.Log("LoadIndex", "done, error %v", perr)
debug.Log("LoadIndex", "checking for duplicate packs")
for packID := range c.packs {
debug.Log("LoadIndex", " check pack %v: contained in %d indexes", packID.Str(), len(packToIndex[packID]))
if len(packToIndex[packID]) > 1 {
hints = append(hints, ErrDuplicatePacks{
PackID: packID,
Indexes: packToIndex[packID],
})
}
}
c.repo.SetIndex(c.masterIndex)
return hints, errs
}
// PackError describes an error with a specific pack.
type PackError struct {
ID backend.ID
Orphaned bool
Err error
}
func (e PackError) Error() string {
return "pack " + e.ID.String() + ": " + e.Err.Error()
}
func packIDTester(repo *repository.Repository, inChan <-chan backend.ID, errChan chan<- error, wg *sync.WaitGroup, done <-chan struct{}) {
debug.Log("Checker.testPackID", "worker start")
defer debug.Log("Checker.testPackID", "worker done")
defer wg.Done()
for id := range inChan {
ok, err := repo.Backend().Test(backend.Data, id.String())
if err != nil {
err = PackError{ID: id, Err: err}
} else {
if !ok {
err = PackError{ID: id, Err: errors.New("does not exist")}
}
}
if err != nil {
debug.Log("Checker.testPackID", "error checking for pack %s: %v", id.Str(), err)
select {
case <-done:
return
case errChan <- err:
}
continue
}
debug.Log("Checker.testPackID", "pack %s exists", id.Str())
}
}
// 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.
func (c *Checker) Packs(errChan chan<- error, done <-chan struct{}) {
defer close(errChan)
debug.Log("Checker.Packs", "checking for %d packs", len(c.packs))
seenPacks := make(map[backend.ID]struct{})
var workerWG sync.WaitGroup
IDChan := make(chan backend.ID)
for i := 0; i < defaultParallelism; i++ {
workerWG.Add(1)
go packIDTester(c.repo, IDChan, errChan, &workerWG, done)
}
for id := range c.packs {
seenPacks[id] = struct{}{}
IDChan <- id
}
close(IDChan)
debug.Log("Checker.Packs", "waiting for %d workers to terminate", defaultParallelism)
workerWG.Wait()
debug.Log("Checker.Packs", "workers terminated")
for id := range c.repo.List(backend.Data, done) {
debug.Log("Checker.Packs", "check data blob %v", id.Str())
if _, ok := seenPacks[id]; !ok {
c.orphanedPacks = append(c.orphanedPacks, id)
select {
case <-done:
return
case errChan <- PackError{ID: id, Orphaned: true, Err: errors.New("not referenced in any index")}:
}
}
}
}
// Error is an error that occurred while checking a repository.
type Error struct {
TreeID *backend.ID
BlobID *backend.ID
Err error
}
func (e Error) Error() string {
if e.BlobID != nil && e.TreeID != nil {
msg := "tree " + e.TreeID.Str()
msg += ", blob " + e.BlobID.Str()
msg += ": " + e.Err.Error()
return msg
}
if e.TreeID != nil {
return "tree " + e.TreeID.Str() + ": " + e.Err.Error()
}
return e.Err.Error()
}
func loadTreeFromSnapshot(repo *repository.Repository, id backend.ID) (backend.ID, error) {
sn, err := restic.LoadSnapshot(repo, id)
if err != nil {
debug.Log("Checker.loadTreeFromSnapshot", "error loading snapshot %v: %v", id.Str(), err)
return backend.ID{}, err
}
if sn.Tree == nil {
debug.Log("Checker.loadTreeFromSnapshot", "snapshot %v has no tree", id.Str())
return backend.ID{}, fmt.Errorf("snapshot %v has no tree", id)
}
return *sn.Tree, nil
}
// loadSnapshotTreeIDs loads all snapshots from backend and returns the tree IDs.
func loadSnapshotTreeIDs(repo *repository.Repository) (backend.IDs, []error) {
var trees struct {
IDs backend.IDs
sync.Mutex
}
var errs struct {
errs []error
sync.Mutex
}
snapshotWorker := func(strID string, done <-chan struct{}) error {
id, err := backend.ParseID(strID)
if err != nil {
return err
}
debug.Log("Checker.Snaphots", "load snapshot %v", id.Str())
treeID, err := loadTreeFromSnapshot(repo, id)
if err != nil {
errs.Lock()
errs.errs = append(errs.errs, err)
errs.Unlock()
return nil
}
debug.Log("Checker.Snaphots", "snapshot %v has tree %v", id.Str(), treeID.Str())
trees.Lock()
trees.IDs = append(trees.IDs, treeID)
trees.Unlock()
return nil
}
err := repository.FilesInParallel(repo.Backend(), backend.Snapshot, defaultParallelism, snapshotWorker)
if err != nil {
errs.errs = append(errs.errs, err)
}
return trees.IDs, errs.errs
}
// TreeError collects several errors that occurred while processing a tree.
type TreeError struct {
ID backend.ID
Errors []error
}
func (e TreeError) Error() string {
return fmt.Sprintf("%v: %d errors", e.ID.String(), len(e.Errors))
}
type treeJob struct {
backend.ID
error
*restic.Tree
}
// loadTreeWorker loads trees from repo and sends them to out.
func loadTreeWorker(repo *repository.Repository,
in <-chan backend.ID, out chan<- treeJob,
done <-chan struct{}, wg *sync.WaitGroup) {
defer func() {
debug.Log("checker.loadTreeWorker", "exiting")
wg.Done()
}()
var (
inCh = in
outCh = out
job treeJob
)
outCh = nil
for {
select {
case <-done:
return
case treeID, ok := <-inCh:
if !ok {
return
}
debug.Log("checker.loadTreeWorker", "load tree %v", treeID.Str())
tree, err := restic.LoadTree(repo, treeID)
debug.Log("checker.loadTreeWorker", "load tree %v (%v) returned err: %v", tree, treeID.Str(), err)
job = treeJob{ID: treeID, error: err, Tree: tree}
outCh = out
inCh = nil
case outCh <- job:
debug.Log("checker.loadTreeWorker", "sent tree %v", job.ID.Str())
outCh = nil
inCh = in
}
}
}
// checkTreeWorker checks the trees received and sends out errors to errChan.
func (c *Checker) checkTreeWorker(in <-chan treeJob, out chan<- error, done <-chan struct{}, wg *sync.WaitGroup) {
defer func() {
debug.Log("checker.checkTreeWorker", "exiting")
wg.Done()
}()
var (
inCh = in
outCh = out
treeError TreeError
)
outCh = nil
for {
select {
case <-done:
debug.Log("checker.checkTreeWorker", "done channel closed, exiting")
return
case job, ok := <-inCh:
if !ok {
debug.Log("checker.checkTreeWorker", "input channel closed, exiting")
return
}
id := job.ID
alreadyChecked := false
c.blobRefs.Lock()
if c.blobRefs.M[id] > 0 {
alreadyChecked = true
}
c.blobRefs.M[id]++
debug.Log("checker.checkTreeWorker", "tree %v refcount %d", job.ID.Str(), c.blobRefs.M[id])
c.blobRefs.Unlock()
if alreadyChecked {
continue
}
debug.Log("checker.checkTreeWorker", "check tree %v (tree %v, err %v)", job.ID.Str(), job.Tree, job.error)
var errs []error
if job.error != nil {
errs = append(errs, job.error)
} else {
errs = c.checkTree(job.ID, job.Tree)
}
if len(errs) > 0 {
debug.Log("checker.checkTreeWorker", "checked tree %v: %v errors", job.ID.Str(), len(errs))
treeError = TreeError{ID: job.ID, Errors: errs}
outCh = out
inCh = nil
}
case outCh <- treeError:
debug.Log("checker.checkTreeWorker", "tree %v: sent %d errors", treeError.ID, len(treeError.Errors))
outCh = nil
inCh = in
}
}
}
func filterTrees(backlog backend.IDs, loaderChan chan<- backend.ID, in <-chan treeJob, out chan<- treeJob, done <-chan struct{}) {
defer func() {
debug.Log("checker.filterTrees", "closing output channels")
close(loaderChan)
close(out)
}()
var (
inCh = in
outCh = out
loadCh = loaderChan
job treeJob
nextTreeID backend.ID
outstandingLoadTreeJobs = 0
)
outCh = nil
loadCh = nil
for {
if loadCh == nil && len(backlog) > 0 {
loadCh = loaderChan
nextTreeID, backlog = backlog[0], backlog[1:]
}
if loadCh == nil && outCh == nil && outstandingLoadTreeJobs == 0 {
debug.Log("checker.filterTrees", "backlog is empty, all channels nil, exiting")
return
}
select {
case <-done:
return
case loadCh <- nextTreeID:
outstandingLoadTreeJobs++
loadCh = nil
case j, ok := <-inCh:
if !ok {
debug.Log("checker.filterTrees", "input channel closed")
inCh = nil
in = nil
continue
}
outstandingLoadTreeJobs--
debug.Log("checker.filterTrees", "input job tree %v", j.ID.Str())
var err error
if j.error != nil {
debug.Log("checker.filterTrees", "received job with error: %v (tree %v, ID %v)", j.error, j.Tree, j.ID.Str())
} else if j.Tree == nil {
debug.Log("checker.filterTrees", "received job with nil tree pointer: %v (ID %v)", j.error, j.ID.Str())
err = errors.New("tree is nil and error is nil")
} else {
debug.Log("checker.filterTrees", "subtrees for tree %v: %v", j.ID.Str(), j.Tree.Subtrees())
for _, id := range j.Tree.Subtrees() {
if id.IsNull() {
// We do not need to raise this error here, it is
// checked when the tree is checked. Just make sure
// that we do not add any null IDs to the backlog.
debug.Log("checker.filterTrees", "tree %v has nil subtree", j.ID.Str())
continue
}
backlog = append(backlog, id)
}
}
if err != nil {
// send a new job with the new error instead of the old one
j = treeJob{ID: j.ID, error: err}
}
job = j
outCh = out
inCh = nil
case outCh <- job:
outCh = nil
inCh = in
}
}
}
// 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(errChan chan<- error, done <-chan struct{}) {
defer close(errChan)
trees, errs := loadSnapshotTreeIDs(c.repo)
debug.Log("checker.Structure", "need to check %d trees from snapshots, %d errs returned", len(trees), len(errs))
for _, err := range errs {
select {
case <-done:
return
case errChan <- err:
}
}
treeIDChan := make(chan backend.ID)
treeJobChan1 := make(chan treeJob)
treeJobChan2 := make(chan treeJob)
var wg sync.WaitGroup
for i := 0; i < defaultParallelism; i++ {
wg.Add(2)
go loadTreeWorker(c.repo, treeIDChan, treeJobChan1, done, &wg)
go c.checkTreeWorker(treeJobChan2, errChan, done, &wg)
}
filterTrees(trees, treeIDChan, treeJobChan1, treeJobChan2, done)
wg.Wait()
}
func (c *Checker) checkTree(id backend.ID, tree *restic.Tree) (errs []error) {
debug.Log("Checker.checkTree", "checking tree %v", id.Str())
var blobs []backend.ID
for _, node := range tree.Nodes {
switch node.Type {
case "file":
for b, blobID := range node.Content {
if blobID.IsNull() {
errs = append(errs, Error{TreeID: &id, Err: fmt.Errorf("file %q blob %d has null ID", node.Name, b)})
continue
}
blobs = append(blobs, blobID)
}
case "dir":
if node.Subtree == nil {
errs = append(errs, Error{TreeID: &id, Err: fmt.Errorf("dir node %q has no subtree", node.Name)})
continue
}
if node.Subtree.IsNull() {
errs = append(errs, Error{TreeID: &id, Err: fmt.Errorf("dir node %q subtree id is null", node.Name)})
continue
}
}
}
for _, blobID := range blobs {
c.blobRefs.Lock()
c.blobRefs.M[blobID]++
debug.Log("Checker.checkTree", "blob %v refcount %d", blobID.Str(), c.blobRefs.M[blobID])
c.blobRefs.Unlock()
if _, ok := c.blobs[blobID]; !ok {
debug.Log("Checker.trees", "tree %v references blob %v which isn't contained in index", id.Str(), blobID.Str())
errs = append(errs, Error{TreeID: &id, BlobID: &blobID, Err: errors.New("not found in index")})
}
}
return errs
}
// UnusedBlobs returns all blobs that have never been referenced.
func (c *Checker) UnusedBlobs() (blobs backend.IDs) {
c.blobRefs.Lock()
defer c.blobRefs.Unlock()
debug.Log("Checker.UnusedBlobs", "checking %d blobs", len(c.blobs))
for id := range c.blobs {
if c.blobRefs.M[id] == 0 {
debug.Log("Checker.UnusedBlobs", "blob %v not referenced", id.Str())
blobs = append(blobs, id)
}
}
return blobs
}
// OrphanedPacks returns a slice of unused packs (only available after Packs() was run).
func (c *Checker) OrphanedPacks() backend.IDs {
return c.orphanedPacks
}