Merge pull request #3730 from MichaelEischer/stricter-check

Let `check` warn about legacy variants of the repo format version 1

changelog/unreleased/issue-3295

@@ -0,0 +1,12 @@
+Change: Deprecate `check --check-unused` and add further checks
+
+Since restic 0.12.0, it is expected to still have unused blobs after running
+`prune`. This made the `check --check-unused` rather useless and tended to
+confuse users. The options has been deprecated and is now ignored.
+
+`check` now also warns if a repository is using either the legacy S3 layout or
+mixed pack files with both tree and data blobs. The latter is known to cause
+performance problems.
+
+https://github.com/restic/restic/issues/3295
+https://github.com/restic/restic/pull/3730

cmd/restic/cmd_check.go

@@ -57,7 +57,13 @@ func init() {
 	f := cmdCheck.Flags()
 	f.BoolVar(&checkOptions.ReadData, "read-data", false, "read all data blobs")
 	f.StringVar(&checkOptions.ReadDataSubset, "read-data-subset", "", "read a `subset` of data packs, specified as 'n/t' for specific part, or either 'x%' or 'x.y%' or a size in bytes with suffixes k/K, m/M, g/G, t/T for a random subset")
-	f.BoolVar(&checkOptions.CheckUnused, "check-unused", false, "find unused blobs")
+	var ignored bool
+	f.BoolVar(&ignored, "check-unused", false, "find unused blobs")
+	err := f.MarkDeprecated("check-unused", "`--check-unused` is deprecated and will be ignored")
+	if err != nil {
+		// MarkDeprecated only returns an error when the flag is not found
+		panic(err)
+	}
 	f.BoolVar(&checkOptions.WithCache, "with-cache", false, "use the cache")
 }
 
@@ -221,11 +227,15 @@ func runCheck(opts CheckOptions, gopts GlobalOptions, args []string) error {
 
 	errorsFound := false
 	suggestIndexRebuild := false
+	mixedFound := false
 	for _, hint := range hints {
 		switch hint.(type) {
 		case *checker.ErrDuplicatePacks, *checker.ErrOldIndexFormat:
 			Printf("%v\n", hint)
 			suggestIndexRebuild = true
+		case *checker.ErrMixedPack:
+			Printf("%v\n", hint)
+			mixedFound = true
 		default:
 			Warnf("error: %v\n", hint)
 			errorsFound = true
@@ -235,6 +245,9 @@ func runCheck(opts CheckOptions, gopts GlobalOptions, args []string) error {
 	if suggestIndexRebuild {
 		Printf("This is non-critical, you can run `restic rebuild-index' to correct this\n")
 	}
+	if mixedFound {
+		Printf("Mixed packs with tree and data blobs are non-critical, you can run `restic prune` to correct this.\n")
+	}
 
 	if len(errs) > 0 {
 		for _, err := range errs {
@@ -253,10 +266,12 @@ func runCheck(opts CheckOptions, gopts GlobalOptions, args []string) error {
 		if checker.IsOrphanedPack(err) {
 			orphanedPacks++
 			Verbosef("%v\n", err)
-			continue
+		} else if _, ok := err.(*checker.ErrLegacyLayout); ok {
+			Verbosef("repository still uses the S3 legacy layout\nPlease run `restic migrate s3legacy` to correct this.\n")
+		} else {
+			errorsFound = true
+			Warnf("%v\n", err)
 		}
-		errorsFound = true
-		Warnf("error: %v\n", err)
 	}
 
 	if orphanedPacks > 0 {

internal/checker/checker.go

@@ -13,6 +13,8 @@ import (
 
 	"github.com/minio/sha256-simd"
 	"github.com/restic/restic/internal/backend"
+	"github.com/restic/restic/internal/backend/s3"
+	"github.com/restic/restic/internal/cache"
 	"github.com/restic/restic/internal/debug"
 	"github.com/restic/restic/internal/errors"
 	"github.com/restic/restic/internal/hashing"
@@ -56,6 +58,13 @@ func New(repo restic.Repository, trackUnused bool) *Checker {
 	return c
 }
 
+// ErrLegacyLayout is returned when the repository uses the S3 legacy layout.
+type ErrLegacyLayout struct{}
+
+func (e *ErrLegacyLayout) Error() string {
+	return "repository uses S3 legacy layout"
+}
+
 // ErrDuplicatePacks is returned when a pack is found in more than one index.
 type ErrDuplicatePacks struct {
 	PackID  restic.ID
@@ -66,6 +75,15 @@ func (e *ErrDuplicatePacks) Error() string {
 	return fmt.Sprintf("pack %v contained in several indexes: %v", e.PackID, e.Indexes)
 }
 
+// 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 {
@@ -141,6 +159,11 @@ func (c *Checker) LoadIndex(ctx context.Context) (hints []error, errs []error) {
 				Indexes: packToIndex[packID],
 			})
 		}
+		if c.masterIndex.IsMixedPack(packID) {
+			hints = append(hints, &ErrMixedPack{
+				PackID: packID,
+			})
+		}
 	}
 
 	err = c.repo.SetIndex(c.masterIndex)
@@ -170,12 +193,30 @@ func IsOrphanedPack(err error) bool {
 	return errors.As(err, &e) && e.Orphaned
 }
 
+func isS3Legacy(b restic.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"
+}
+
 // 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(ctx context.Context, errChan chan<- error) {
 	defer close(errChan)
 
+	if isS3Legacy(c.repo.Backend()) {
+		errChan <- &ErrLegacyLayout{}
+	}
+
 	debug.Log("checking for %d packs", len(c.packs))
 
 	debug.Log("listing repository packs")

internal/checker/checker_test.go

@@ -63,6 +63,14 @@ func checkData(chkr *checker.Checker) []error {
 	)
 }
 
+func assertOnlyMixedPackHints(t *testing.T, hints []error) {
+	for _, err := range hints {
+		if _, ok := err.(*checker.ErrMixedPack); !ok {
+			t.Fatalf("expected mixed pack hint, got %v", err)
+		}
+	}
+}
+
 func TestCheckRepo(t *testing.T) {
 	repodir, cleanup := test.Env(t, checkerTestData)
 	defer cleanup()
@@ -74,9 +82,9 @@ func TestCheckRepo(t *testing.T) {
 	if len(errs) > 0 {
 		t.Fatalf("expected no errors, got %v: %v", len(errs), errs)
 	}
-
-	if len(hints) > 0 {
-		t.Errorf("expected no hints, got %v: %v", len(hints), hints)
+	assertOnlyMixedPackHints(t, hints)
+	if len(hints) == 0 {
+		t.Fatal("expected mixed pack warnings, got none")
 	}
 
 	test.OKs(t, checkPacks(chkr))
@@ -100,10 +108,7 @@ func TestMissingPack(t *testing.T) {
 	if len(errs) > 0 {
 		t.Fatalf("expected no errors, got %v: %v", len(errs), errs)
 	}
-
-	if len(hints) > 0 {
-		t.Errorf("expected no hints, got %v: %v", len(hints), hints)
-	}
+	assertOnlyMixedPackHints(t, hints)
 
 	errs = checkPacks(chkr)
 
@@ -136,10 +141,7 @@ func TestUnreferencedPack(t *testing.T) {
 	if len(errs) > 0 {
 		t.Fatalf("expected no errors, got %v: %v", len(errs), errs)
 	}
-
-	if len(hints) > 0 {
-		t.Errorf("expected no hints, got %v: %v", len(hints), hints)
-	}
+	assertOnlyMixedPackHints(t, hints)
 
 	errs = checkPacks(chkr)
 
@@ -181,10 +183,7 @@ func TestUnreferencedBlobs(t *testing.T) {
 	if len(errs) > 0 {
 		t.Fatalf("expected no errors, got %v: %v", len(errs), errs)
 	}
-
-	if len(hints) > 0 {
-		t.Errorf("expected no hints, got %v: %v", len(hints), hints)
-	}
+	assertOnlyMixedPackHints(t, hints)
 
 	test.OKs(t, checkPacks(chkr))
 	test.OKs(t, checkStruct(chkr))
@@ -269,9 +268,7 @@ func TestModifiedIndex(t *testing.T) {
 		t.Logf("found expected error %v", err)
 	}
 
-	if len(hints) > 0 {
-		t.Errorf("expected no hints, got %v: %v", len(hints), hints)
-	}
+	assertOnlyMixedPackHints(t, hints)
 }
 
 var checkerDuplicateIndexTestData = filepath.Join("testdata", "duplicate-packs-in-index-test-repo.tar.gz")
@@ -421,10 +418,7 @@ func TestCheckerNoDuplicateTreeDecodes(t *testing.T) {
 	if len(errs) > 0 {
 		t.Fatalf("expected no errors, got %v: %v", len(errs), errs)
 	}
-
-	if len(hints) > 0 {
-		t.Errorf("expected no hints, got %v: %v", len(hints), hints)
-	}
+	assertOnlyMixedPackHints(t, hints)
 
 	test.OKs(t, checkPacks(chkr))
 	test.OKs(t, checkStruct(chkr))
@@ -572,8 +566,10 @@ func loadBenchRepository(t *testing.B) (*checker.Checker, restic.Repository, fun
 		t.Fatalf("expected no errors, got %v: %v", len(errs), errs)
 	}
 
-	if len(hints) > 0 {
-		t.Errorf("expected no hints, got %v: %v", len(hints), hints)
+	for _, err := range hints {
+		if _, ok := err.(*checker.ErrMixedPack); !ok {
+			t.Fatalf("expected mixed pack hint, got %v", err)
+		}
 	}
 	return chkr, repo, cleanup
 }

internal/migrations/s3_layout.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/restic/restic/internal/backend"
 	"github.com/restic/restic/internal/backend/s3"
+	"github.com/restic/restic/internal/cache"
 	"github.com/restic/restic/internal/debug"
 	"github.com/restic/restic/internal/errors"
 	"github.com/restic/restic/internal/restic"
@@ -21,10 +22,25 @@ func init() {
 // "default" layout.
 type S3Layout struct{}
 
+func toS3Backend(repo restic.Repository) *s3.Backend {
+	b := repo.Backend()
+	// unwrap cache
+	if be, ok := b.(*cache.Backend); ok {
+		b = be.Backend
+	}
+
+	be, ok := b.(*s3.Backend)
+	if !ok {
+		debug.Log("backend is not s3")
+		return nil
+	}
+	return be
+}
+
 // Check tests whether the migration can be applied.
 func (m *S3Layout) Check(ctx context.Context, repo restic.Repository) (bool, error) {
-	be, ok := repo.Backend().(*s3.Backend)
-	if !ok {
+	be := toS3Backend(repo)
+	if be == nil {
 		debug.Log("backend is not s3")
 		return false, nil
 	}
@@ -75,8 +91,8 @@ func (m *S3Layout) moveFiles(ctx context.Context, be *s3.Backend, l backend.Layo
 
 // Apply runs the migration.
 func (m *S3Layout) Apply(ctx context.Context, repo restic.Repository) error {
-	be, ok := repo.Backend().(*s3.Backend)
-	if !ok {
+	be := toS3Backend(repo)
+	if be == nil {
 		debug.Log("backend is not s3")
 		return errors.New("backend is not s3")
 	}