detached 5c87cd6

fix(snapshot): budget temp shard traversal

commit
5c87cd625b13473233e84fcf54a3cff6788a1098
author
brice · · 2026-07-22 03:26 UTC
parent
26baad6
signature
GPG VerifiedCD88F9E564E0102646FB6077A1A07C7C7C3E349D · arch-gpg Verified for the committer email
4 files · +97 -34
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M internal/adapters/snapshot/load_bounds_test.go +7 -1
@@ -75,10 +75,16 @@ func TestRepositoryMaintainDoesNotCollectBeyondRetainedMetadataBudget(t *testing
7575 t.Fatal(err)
7676 }
7777 }
78- for pass := 0; pass < 3; pass++ {
78+ for pass := 0; pass < maxMaintenanceMarkedGenerations*3; pass++ {
7979 if err := repo.Maintain(context.Background()); err != nil {
8080 t.Fatal(err)
8181 }
82+ if repo.maintenanceSessions[sessionKey("named")] == nil {
83+ break
84+ }
85+ if pass == maxMaintenanceMarkedGenerations*3-1 {
86+ t.Fatal("maintenance did not complete after bounded object-shard traversal")
87+ }
8288 }
8389 if _, err := os.Lstat(repo.manifestPath(sessionKey("named"), 1)); err != nil {
8490 t.Fatalf("old manifest collected after mark budget overflow: %v", err)
@@ -75,10 +75,16 @@ func TestRepositoryMaintainDoesNotCollectBeyondRetainedMetadataBudget(t *testing
75 t.Fatal(err)75 t.Fatal(err)
76 }76 }
77 }77 }
78- for pass := 0; pass < 3; pass++ {78+ for pass := 0; pass < maxMaintenanceMarkedGenerations*3; pass++ {
79 if err := repo.Maintain(context.Background()); err != nil {79 if err := repo.Maintain(context.Background()); err != nil {
80 t.Fatal(err)80 t.Fatal(err)
81 }81 }
82+ if repo.maintenanceSessions[sessionKey("named")] == nil {
83+ break
84+ }
85+ if pass == maxMaintenanceMarkedGenerations*3-1 {
86+ t.Fatal("maintenance did not complete after bounded object-shard traversal")
87+ }
82 }88 }
83 if _, err := os.Lstat(repo.manifestPath(sessionKey("named"), 1)); err != nil {89 if _, err := os.Lstat(repo.manifestPath(sessionKey("named"), 1)); err != nil {
84 t.Fatalf("old manifest collected after mark budget overflow: %v", err)90 t.Fatalf("old manifest collected after mark budget overflow: %v", err)
M internal/adapters/snapshot/maintenance_gc.go +28 -30
@@ -268,39 +268,37 @@ func (r *Repository) removeObsoleteManifests(ctx context.Context, key string, st
268268 return nil
269269 }
270270
271-// removeObjectTemps processes a single shard to completion before advancing
272-// the shard-root cursor. Thus a hostile set of shards can retain at most the
273-// root cursor and the one active shard cursor, rather than one cursor per
274-// discovered shard.
271+// removeObjectTemps performs at most one shard traversal or one root-entry
272+// discovery per Maintain call. Empty attacker-controlled shards consume no
273+// removal budget, so this fixed step ceiling prevents an unbounded scan of
274+// them while retaining only the root cursor and one active shard cursor.
275275 func (r *Repository) removeObjectTemps(ctx context.Context, key string, state *sessionMaintenance, budget *int) (bool, error) {
276276 root := filepath.Join(r.sessionPath(key), repositoryObjectsDir)
277- for *budget > 0 {
278- if state.objectTempShard != "" {
279- done, err := r.removeTemps(ctx, filepath.Join(root, state.objectTempShard), budget, "object-temps:"+key+":"+state.objectTempShard)
280- if err != nil || !done {
281- return false, err
282- }
283- // This releases the active shard cursor before the next root entry
284- // is discovered. A completed small shard may therefore advance in
285- // this call without accumulating continuation state.
286- state.objectTempShard = ""
287- continue
288- }
289- if state.objectTempsDone {
290- return true, nil
291- }
292- entries, done, err := r.readMaintenanceDir(root, 1, "object-temps-shards:"+key)
293- if errors.Is(err, os.ErrNotExist) {
294- state.objectTempsDone = true
295- return true, nil
296- }
297- if err != nil {
298- return false, fmt.Errorf("read snapshot object shards: %w", safeFilesystemError(err))
299- }
300- state.objectTempsDone = done
301- if len(entries) != 0 && entries[0].isDir {
302- state.objectTempShard = entries[0].name
277+ if *budget == 0 {
278+ return false, nil
279+ }
280+ if state.objectTempShard != "" {
281+ done, err := r.removeTemps(ctx, filepath.Join(root, state.objectTempShard), budget, "object-temps:"+key+":"+state.objectTempShard)
282+ if err != nil || !done {
283+ return false, err
303284 }
285+ state.objectTempShard = ""
286+ return state.objectTempsDone, nil
287+ }
288+ if state.objectTempsDone {
289+ return true, nil
290+ }
291+ entries, done, err := r.readMaintenanceDir(root, 1, "object-temps-shards:"+key)
292+ if errors.Is(err, os.ErrNotExist) {
293+ state.objectTempsDone = true
294+ return true, nil
295+ }
296+ if err != nil {
297+ return false, fmt.Errorf("read snapshot object shards: %w", safeFilesystemError(err))
298+ }
299+ state.objectTempsDone = done
300+ if len(entries) != 0 && entries[0].isDir {
301+ state.objectTempShard = entries[0].name
304302 }
305303 return state.objectTempsDone && state.objectTempShard == "", nil
306304 }
@@ -268,39 +268,37 @@ func (r *Repository) removeObsoleteManifests(ctx context.Context, key string, st
268 return nil268 return nil
269 }269 }
270 270
271-// removeObjectTemps processes a single shard to completion before advancing271+// removeObjectTemps performs at most one shard traversal or one root-entry
272-// the shard-root cursor. Thus a hostile set of shards can retain at most the272+// discovery per Maintain call. Empty attacker-controlled shards consume no
273-// root cursor and the one active shard cursor, rather than one cursor per273+// removal budget, so this fixed step ceiling prevents an unbounded scan of
274-// discovered shard.274+// them while retaining only the root cursor and one active shard cursor.
275 func (r *Repository) removeObjectTemps(ctx context.Context, key string, state *sessionMaintenance, budget *int) (bool, error) {275 func (r *Repository) removeObjectTemps(ctx context.Context, key string, state *sessionMaintenance, budget *int) (bool, error) {
276 root := filepath.Join(r.sessionPath(key), repositoryObjectsDir)276 root := filepath.Join(r.sessionPath(key), repositoryObjectsDir)
277- for *budget > 0 {277+ if *budget == 0 {
278- if state.objectTempShard != "" {278+ return false, nil
279- done, err := r.removeTemps(ctx, filepath.Join(root, state.objectTempShard), budget, "object-temps:"+key+":"+state.objectTempShard)279+ }
280- if err != nil || !done {280+ if state.objectTempShard != "" {
281- return false, err281+ done, err := r.removeTemps(ctx, filepath.Join(root, state.objectTempShard), budget, "object-temps:"+key+":"+state.objectTempShard)
282- }282+ if err != nil || !done {
283- // This releases the active shard cursor before the next root entry283+ return false, err
284- // is discovered. A completed small shard may therefore advance in
285- // this call without accumulating continuation state.
286- state.objectTempShard = ""
287- continue
288- }
289- if state.objectTempsDone {
290- return true, nil
291- }
292- entries, done, err := r.readMaintenanceDir(root, 1, "object-temps-shards:"+key)
293- if errors.Is(err, os.ErrNotExist) {
294- state.objectTempsDone = true
295- return true, nil
296- }
297- if err != nil {
298- return false, fmt.Errorf("read snapshot object shards: %w", safeFilesystemError(err))
299- }
300- state.objectTempsDone = done
301- if len(entries) != 0 && entries[0].isDir {
302- state.objectTempShard = entries[0].name
303 }284 }
285+ state.objectTempShard = ""
286+ return state.objectTempsDone, nil
287+ }
288+ if state.objectTempsDone {
289+ return true, nil
290+ }
291+ entries, done, err := r.readMaintenanceDir(root, 1, "object-temps-shards:"+key)
292+ if errors.Is(err, os.ErrNotExist) {
293+ state.objectTempsDone = true
294+ return true, nil
295+ }
296+ if err != nil {
297+ return false, fmt.Errorf("read snapshot object shards: %w", safeFilesystemError(err))
298+ }
299+ state.objectTempsDone = done
300+ if len(entries) != 0 && entries[0].isDir {
301+ state.objectTempShard = entries[0].name
304 }302 }
305 return state.objectTempsDone && state.objectTempShard == "", nil303 return state.objectTempsDone && state.objectTempShard == "", nil
306 }304 }
M internal/adapters/snapshot/maintenance_hardening_test.go +47 -0
@@ -46,6 +46,53 @@ func TestRepositoryMaintainBoundsCursorsAcrossHostileObjectShards(t *testing.T)
4646 }
4747 }
4848
49+func TestRepositoryMaintainBoundsEmptyObjectTempShards(t *testing.T) {
50+ repo := NewRepository(privateDir(t))
51+ key := sessionKey("named")
52+ objects := filepath.Join(repo.sessionPath(key), repositoryObjectsDir)
53+ const shards = maintenanceBatch * 2
54+ for i := 0; i < shards; i++ {
55+ if err := os.MkdirAll(filepath.Join(objects, fmt.Sprintf("%03d", i)), 0o700); err != nil {
56+ t.Fatal(err)
57+ }
58+ }
59+
60+ openedShards := make(map[string]struct{}, shards)
61+ opensThisPass := 0
62+ tempPass := false
63+ repo.hooks.openMaintenanceDirectory = func(dir string) (maintenanceDirectory, error) {
64+ if tempPass && filepath.Dir(dir) == objects {
65+ opensThisPass++
66+ openedShards[dir] = struct{}{}
67+ }
68+ file, err := os.Open(dir)
69+ if err != nil {
70+ return nil, err
71+ }
72+ return osMaintenanceDirectory{file: file}, nil
73+ }
74+
75+ for pass := 0; pass < shards*3; pass++ {
76+ opensThisPass = 0
77+ tempPass = true
78+ if err := repo.Maintain(context.Background()); err != nil {
79+ t.Fatal(err)
80+ }
81+ tempPass = false
82+ if opensThisPass > 1 {
83+ t.Fatalf("empty object shards opened in maintenance pass %d = %d, want at most 1", pass, opensThisPass)
84+ }
85+ state := repo.maintenanceSessions[key]
86+ if state != nil && state.objectTempsDone {
87+ if got := len(openedShards); got != shards {
88+ t.Fatalf("empty object shards opened = %d, want %d", got, shards)
89+ }
90+ return
91+ }
92+ }
93+ t.Fatal("empty object temp shards were not eventually traversed")
94+}
95+
4996 func TestRepositoryMaintainBoundsAndResumesDeepWideQuarantine(t *testing.T) {
5097 repo := NewRepository(privateDir(t))
5198 quarantine := filepath.Join(repo.dir, repositorySessionsDir, ".deleting-hostile")
@@ -46,6 +46,53 @@ func TestRepositoryMaintainBoundsCursorsAcrossHostileObjectShards(t *testing.T)
46 }46 }
47 }47 }
48 48
49+func TestRepositoryMaintainBoundsEmptyObjectTempShards(t *testing.T) {
50+ repo := NewRepository(privateDir(t))
51+ key := sessionKey("named")
52+ objects := filepath.Join(repo.sessionPath(key), repositoryObjectsDir)
53+ const shards = maintenanceBatch * 2
54+ for i := 0; i < shards; i++ {
55+ if err := os.MkdirAll(filepath.Join(objects, fmt.Sprintf("%03d", i)), 0o700); err != nil {
56+ t.Fatal(err)
57+ }
58+ }
59+
60+ openedShards := make(map[string]struct{}, shards)
61+ opensThisPass := 0
62+ tempPass := false
63+ repo.hooks.openMaintenanceDirectory = func(dir string) (maintenanceDirectory, error) {
64+ if tempPass && filepath.Dir(dir) == objects {
65+ opensThisPass++
66+ openedShards[dir] = struct{}{}
67+ }
68+ file, err := os.Open(dir)
69+ if err != nil {
70+ return nil, err
71+ }
72+ return osMaintenanceDirectory{file: file}, nil
73+ }
74+
75+ for pass := 0; pass < shards*3; pass++ {
76+ opensThisPass = 0
77+ tempPass = true
78+ if err := repo.Maintain(context.Background()); err != nil {
79+ t.Fatal(err)
80+ }
81+ tempPass = false
82+ if opensThisPass > 1 {
83+ t.Fatalf("empty object shards opened in maintenance pass %d = %d, want at most 1", pass, opensThisPass)
84+ }
85+ state := repo.maintenanceSessions[key]
86+ if state != nil && state.objectTempsDone {
87+ if got := len(openedShards); got != shards {
88+ t.Fatalf("empty object shards opened = %d, want %d", got, shards)
89+ }
90+ return
91+ }
92+ }
93+ t.Fatal("empty object temp shards were not eventually traversed")
94+}
95+
49 func TestRepositoryMaintainBoundsAndResumesDeepWideQuarantine(t *testing.T) {96 func TestRepositoryMaintainBoundsAndResumesDeepWideQuarantine(t *testing.T) {
50 repo := NewRepository(privateDir(t))97 repo := NewRepository(privateDir(t))
51 quarantine := filepath.Join(repo.dir, repositorySessionsDir, ".deleting-hostile")98 quarantine := filepath.Join(repo.dir, repositorySessionsDir, ".deleting-hostile")
M internal/adapters/snapshot/maintenance_test.go +15 -3
@@ -178,10 +178,22 @@ func TestRepositoryMaintainRetainsNewestTwoCompleteGenerations(t *testing.T) {
178178 t.Fatal(err)
179179 }
180180 }
181- if err := repo.Maintain(context.Background()); err != nil {
182- t.Fatal(err)
183- }
184181 key := sessionKey("named")
182+ for pass := 0; pass < maintenanceBatch; pass++ {
183+ if err := repo.Maintain(context.Background()); err != nil {
184+ t.Fatal(err)
185+ }
186+ _, err := os.Lstat(repo.manifestPath(key, 1))
187+ if errors.Is(err, os.ErrNotExist) {
188+ break
189+ }
190+ if err != nil {
191+ t.Fatalf("old manifest during Maintain = %v", err)
192+ }
193+ if pass == maintenanceBatch-1 {
194+ t.Fatal("old manifest was not eventually collected")
195+ }
196+ }
185197 for _, generation := range []uint64{2, 3} {
186198 if _, err := os.Lstat(repo.manifestPath(key, generation)); err != nil {
187199 t.Fatalf("retained manifest %d: %v", generation, err)
@@ -178,10 +178,22 @@ func TestRepositoryMaintainRetainsNewestTwoCompleteGenerations(t *testing.T) {
178 t.Fatal(err)178 t.Fatal(err)
179 }179 }
180 }180 }
181- if err := repo.Maintain(context.Background()); err != nil {
182- t.Fatal(err)
183- }
184 key := sessionKey("named")181 key := sessionKey("named")
182+ for pass := 0; pass < maintenanceBatch; pass++ {
183+ if err := repo.Maintain(context.Background()); err != nil {
184+ t.Fatal(err)
185+ }
186+ _, err := os.Lstat(repo.manifestPath(key, 1))
187+ if errors.Is(err, os.ErrNotExist) {
188+ break
189+ }
190+ if err != nil {
191+ t.Fatalf("old manifest during Maintain = %v", err)
192+ }
193+ if pass == maintenanceBatch-1 {
194+ t.Fatal("old manifest was not eventually collected")
195+ }
196+ }
185 for _, generation := range []uint64{2, 3} {197 for _, generation := range []uint64{2, 3} {
186 if _, err := os.Lstat(repo.manifestPath(key, generation)); err != nil {198 if _, err := os.Lstat(repo.manifestPath(key, generation)); err != nil {
187 t.Fatalf("retained manifest %d: %v", generation, err)199 t.Fatalf("retained manifest %d: %v", generation, err)

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