MyFSIO v0.3.6 Release

Reviewed-on: #29

app/__init__.py

@@ -1,13 +1,13 @@
 from __future__ import annotations
 
 import html as html_module
+import itertools
 import logging
 import mimetypes
 import os
 import shutil
 import sys
 import time
-import uuid
 from logging.handlers import RotatingFileHandler
 from pathlib import Path
 from datetime import timedelta
@@ -39,6 +39,8 @@ from .storage import ObjectStorage, StorageError
 from .version import get_version
 from .website_domains import WebsiteDomainStore
 
+_request_counter = itertools.count(1)
+
 
 def _migrate_config_file(active_path: Path, legacy_paths: List[Path]) -> Path:
     """Migrate config file from legacy locations to the active path.
@@ -481,13 +483,9 @@ def _configure_logging(app: Flask) -> None:
 
     @app.before_request
     def _log_request_start() -> None:
-        g.request_id = uuid.uuid4().hex
+        g.request_id = f"{os.getpid():x}{next(_request_counter):012x}"
         g.request_started_at = time.perf_counter()
         g.request_bytes_in = request.content_length or 0
-        app.logger.info(
-            "Request started",
-            extra={"path": request.path, "method": request.method, "remote_addr": request.remote_addr},
-        )
 
     @app.before_request
     def _maybe_serve_website():
@@ -616,16 +614,17 @@ def _configure_logging(app: Flask) -> None:
         duration_ms = 0.0
         if hasattr(g, "request_started_at"):
             duration_ms = (time.perf_counter() - g.request_started_at) * 1000
-        request_id = getattr(g, "request_id", uuid.uuid4().hex)
+        request_id = getattr(g, "request_id", f"{os.getpid():x}{next(_request_counter):012x}")
         response.headers.setdefault("X-Request-ID", request_id)
-        app.logger.info(
+        if app.logger.isEnabledFor(logging.INFO):
-            "Request completed",
+            app.logger.info(
-            extra={
+                "Request completed",
-                "path": request.path,
+                extra={
-                "method": request.method,
+                    "path": request.path,
-                "remote_addr": request.remote_addr,
+                    "method": request.method,
-            },
+                    "remote_addr": request.remote_addr,
-        )
+                },
+            )
         response.headers["X-Request-Duration-ms"] = f"{duration_ms:.2f}"
 
         operation_metrics = app.extensions.get("operation_metrics")

app/bucket_policies.py

@@ -2,6 +2,7 @@ from __future__ import annotations
 
 import ipaddress
 import json
+import os
 import re
 import time
 from dataclasses import dataclass, field
@@ -268,7 +269,7 @@ class BucketPolicyStore:
         self._last_mtime = self._current_mtime()
         # Performance: Avoid stat() on every request
         self._last_stat_check = 0.0
-        self._stat_check_interval = 1.0  # Only check mtime every 1 second
+        self._stat_check_interval = float(os.environ.get("BUCKET_POLICY_STAT_CHECK_INTERVAL_SECONDS", "2.0"))
 
     def maybe_reload(self) -> None:
         # Performance: Skip stat check if we checked recently

app/iam.py

@@ -125,7 +125,7 @@ class IamService:
         self._secret_key_cache: Dict[str, Tuple[str, float]] = {}
         self._cache_ttl = float(os.environ.get("IAM_CACHE_TTL_SECONDS", "5.0"))
         self._last_stat_check = 0.0
-        self._stat_check_interval = 1.0
+        self._stat_check_interval = float(os.environ.get("IAM_STAT_CHECK_INTERVAL_SECONDS", "2.0"))
         self._sessions: Dict[str, Dict[str, Any]] = {}
         self._session_lock = threading.Lock()
         self._load()

app/operation_metrics.py

@@ -5,6 +5,7 @@ import logging
 import random
 import threading
 import time
+from collections import defaultdict
 from dataclasses import dataclass, field
 from datetime import datetime, timezone
 from pathlib import Path
@@ -138,8 +139,8 @@ class OperationMetricsCollector:
         self.interval_seconds = interval_minutes * 60
         self.retention_hours = retention_hours
         self._lock = threading.Lock()
-        self._by_method: Dict[str, OperationStats] = {}
+        self._by_method: Dict[str, OperationStats] = defaultdict(OperationStats)
-        self._by_endpoint: Dict[str, OperationStats] = {}
+        self._by_endpoint: Dict[str, OperationStats] = defaultdict(OperationStats)
         self._by_status_class: Dict[str, int] = {}
         self._error_codes: Dict[str, int] = {}
         self._totals = OperationStats()
@@ -211,8 +212,8 @@ class OperationMetricsCollector:
             self._prune_old_snapshots()
             self._save_history()
 
-            self._by_method.clear()
+            self._by_method = defaultdict(OperationStats)
-            self._by_endpoint.clear()
+            self._by_endpoint = defaultdict(OperationStats)
             self._by_status_class.clear()
             self._error_codes.clear()
             self._totals = OperationStats()
@@ -232,12 +233,7 @@ class OperationMetricsCollector:
         status_class = f"{status_code // 100}xx"
 
         with self._lock:
-            if method not in self._by_method:
-                self._by_method[method] = OperationStats()
             self._by_method[method].record(latency_ms, success, bytes_in, bytes_out)
-
-            if endpoint_type not in self._by_endpoint:
-                self._by_endpoint[endpoint_type] = OperationStats()
             self._by_endpoint[endpoint_type].record(latency_ms, success, bytes_in, bytes_out)
 
             self._by_status_class[status_class] = self._by_status_class.get(status_class, 0) + 1

app/s3_api.py

@@ -85,6 +85,9 @@ def _bucket_policies() -> BucketPolicyStore:
 
 
 def _build_policy_context() -> Dict[str, Any]:
+    cached = getattr(g, "_policy_context", None)
+    if cached is not None:
+        return cached
     ctx: Dict[str, Any] = {}
     if request.headers.get("Referer"):
         ctx["aws:Referer"] = request.headers.get("Referer")
@@ -98,6 +101,7 @@ def _build_policy_context() -> Dict[str, Any]:
     ctx["aws:SecureTransport"] = str(request.is_secure).lower()
     if request.headers.get("User-Agent"):
         ctx["aws:UserAgent"] = request.headers.get("User-Agent")
+    g._policy_context = ctx
     return ctx
 
 
@@ -1021,11 +1025,15 @@ def _apply_object_headers(
     file_stat,
     metadata: Dict[str, str] | None,
     etag: str,
+    size_override: int | None = None,
+    mtime_override: float | None = None,
 ) -> None:
-    if file_stat is not None:
+    effective_size = size_override if size_override is not None else (file_stat.st_size if file_stat is not None else None)
-        if response.status_code != 206:
+    effective_mtime = mtime_override if mtime_override is not None else (file_stat.st_mtime if file_stat is not None else None)
-            response.headers["Content-Length"] = str(file_stat.st_size)
+    if effective_size is not None and response.status_code != 206:
-        response.headers["Last-Modified"] = http_date(file_stat.st_mtime)
+        response.headers["Content-Length"] = str(effective_size)
+    if effective_mtime is not None:
+        response.headers["Last-Modified"] = http_date(effective_mtime)
     response.headers["ETag"] = f'"{etag}"'
     response.headers["Accept-Ranges"] = "bytes"
     for key, value in (metadata or {}).items():
@@ -2820,6 +2828,8 @@ def object_handler(bucket_name: str, object_key: str):
         if validation_error:
             return _error_response("InvalidArgument", validation_error, 400)
 
+        metadata["__content_type__"] = content_type or mimetypes.guess_type(object_key)[0] or "application/octet-stream"
+
         try:
             meta = storage.put_object(
                 bucket_name,
@@ -2834,10 +2844,23 @@ def object_handler(bucket_name: str, object_key: str):
             if "Bucket" in message:
                 return _error_response("NoSuchBucket", message, 404)
             return _error_response("InvalidArgument", message, 400)
-        current_app.logger.info(
+
-            "Object uploaded",
+        content_md5 = request.headers.get("Content-MD5")
-            extra={"bucket": bucket_name, "key": object_key, "size": meta.size},
+        if content_md5 and meta.etag:
-        )
+            try:
+                expected_md5 = base64.b64decode(content_md5).hex()
+            except Exception:
+                storage.delete_object(bucket_name, object_key)
+                return _error_response("InvalidDigest", "Content-MD5 header is not valid base64", 400)
+            if expected_md5 != meta.etag:
+                storage.delete_object(bucket_name, object_key)
+                return _error_response("BadDigest", "The Content-MD5 you specified did not match what we received", 400)
+
+        if current_app.logger.isEnabledFor(logging.INFO):
+            current_app.logger.info(
+                "Object uploaded",
+                extra={"bucket": bucket_name, "key": object_key, "size": meta.size},
+            )
         response = Response(status=200)
         if meta.etag:
             response.headers["ETag"] = f'"{meta.etag}"'
@@ -2871,7 +2894,7 @@ def object_handler(bucket_name: str, object_key: str):
         except StorageError as exc:
             return _error_response("NoSuchKey", str(exc), 404)
         metadata = storage.get_object_metadata(bucket_name, object_key)
-        mimetype = mimetypes.guess_type(object_key)[0] or "application/octet-stream"
+        mimetype = metadata.get("__content_type__") or mimetypes.guess_type(object_key)[0] or "application/octet-stream"
         
         is_encrypted = "x-amz-server-side-encryption" in metadata
         
@@ -2963,10 +2986,7 @@ def object_handler(bucket_name: str, object_key: str):
             response.headers["Content-Type"] = mimetype
             logged_bytes = 0
 
-        try:
+        file_stat = stat if not is_encrypted else None
-            file_stat = path.stat() if not is_encrypted else None
-        except (PermissionError, OSError):
-            file_stat = None
         _apply_object_headers(response, file_stat=file_stat, metadata=metadata, etag=etag)
 
         if request.method == "GET":
@@ -2983,8 +3003,9 @@ def object_handler(bucket_name: str, object_key: str):
                 if value:
                     response.headers[header] = _sanitize_header_value(value)
 
-        action = "Object read" if request.method == "GET" else "Object head"
+        if current_app.logger.isEnabledFor(logging.INFO):
-        current_app.logger.info(action, extra={"bucket": bucket_name, "key": object_key, "bytes": logged_bytes})
+            action = "Object read" if request.method == "GET" else "Object head"
+            current_app.logger.info(action, extra={"bucket": bucket_name, "key": object_key, "bytes": logged_bytes})
         return response
 
     if "uploadId" in request.args:
@@ -3002,7 +3023,8 @@ def object_handler(bucket_name: str, object_key: str):
 
     storage.delete_object(bucket_name, object_key)
     lock_service.delete_object_lock_metadata(bucket_name, object_key)
-    current_app.logger.info("Object deleted", extra={"bucket": bucket_name, "key": object_key})
+    if current_app.logger.isEnabledFor(logging.INFO):
+        current_app.logger.info("Object deleted", extra={"bucket": bucket_name, "key": object_key})
 
     principal, _ = _require_principal()
     _notifications().emit_object_removed(
@@ -3343,12 +3365,20 @@ def head_object(bucket_name: str, object_key: str) -> Response:
         _authorize_action(principal, bucket_name, "read", object_key=object_key)
         path = _storage().get_object_path(bucket_name, object_key)
         metadata = _storage().get_object_metadata(bucket_name, object_key)
-        stat = path.stat()
         etag = metadata.get("__etag__") or _storage()._compute_etag(path)
 
-        response = Response(status=200)
+        cached_size = metadata.get("__size__")
-        _apply_object_headers(response, file_stat=stat, metadata=metadata, etag=etag)
+        cached_mtime = metadata.get("__last_modified__")
-        response.headers["Content-Type"] = mimetypes.guess_type(object_key)[0] or "application/octet-stream"
+        if cached_size is not None and cached_mtime is not None:
+            size_val = int(cached_size)
+            mtime_val = float(cached_mtime)
+            response = Response(status=200)
+            _apply_object_headers(response, file_stat=None, metadata=metadata, etag=etag, size_override=size_val, mtime_override=mtime_val)
+        else:
+            stat = path.stat()
+            response = Response(status=200)
+            _apply_object_headers(response, file_stat=stat, metadata=metadata, etag=etag)
+        response.headers["Content-Type"] = metadata.get("__content_type__") or mimetypes.guess_type(object_key)[0] or "application/octet-stream"
         return response
     except (StorageError, FileNotFoundError):
         return _error_response("NoSuchKey", "Object not found", 404)
@@ -3578,6 +3608,8 @@ def _initiate_multipart_upload(bucket_name: str, object_key: str) -> Response:
         return error
     
     metadata = _extract_request_metadata()
+    content_type = request.headers.get("Content-Type")
+    metadata["__content_type__"] = content_type or mimetypes.guess_type(object_key)[0] or "application/octet-stream"
     try:
         upload_id = _storage().initiate_multipart_upload(
             bucket_name,
@@ -3630,6 +3662,15 @@ def _upload_part(bucket_name: str, object_key: str) -> Response:
             return _error_response("NoSuchUpload", str(exc), 404)
         return _error_response("InvalidArgument", str(exc), 400)
 
+    content_md5 = request.headers.get("Content-MD5")
+    if content_md5 and etag:
+        try:
+            expected_md5 = base64.b64decode(content_md5).hex()
+        except Exception:
+            return _error_response("InvalidDigest", "Content-MD5 header is not valid base64", 400)
+        if expected_md5 != etag:
+            return _error_response("BadDigest", "The Content-MD5 you specified did not match what we received", 400)
+
     response = Response(status=200)
     response.headers["ETag"] = f'"{etag}"'
     return response

app/storage.py

@@ -1,6 +1,5 @@
 from __future__ import annotations
 
-import copy
 import hashlib
 import json
 import os
@@ -196,7 +195,9 @@ class ObjectStorage:
         self.root.mkdir(parents=True, exist_ok=True)
         self._ensure_system_roots()
         self._object_cache: OrderedDict[str, tuple[Dict[str, ObjectMeta], float, float]] = OrderedDict()
-        self._cache_lock = threading.Lock()
+        self._obj_cache_lock = threading.Lock()
+        self._meta_cache_lock = threading.Lock()
+        self._registry_lock = threading.Lock()
         self._bucket_locks: Dict[str, threading.Lock] = {}
         self._cache_version: Dict[str, int] = {}
         self._bucket_config_cache: Dict[str, tuple[dict[str, Any], float]] = {}
@@ -209,10 +210,17 @@ class ObjectStorage:
         self._meta_read_cache: OrderedDict[tuple, Optional[Dict[str, Any]]] = OrderedDict()
         self._meta_read_cache_max = 2048
         self._cleanup_executor = ThreadPoolExecutor(max_workers=1, thread_name_prefix="ParentCleanup")
+        self._stats_mem: Dict[str, Dict[str, int]] = {}
+        self._stats_serial: Dict[str, int] = {}
+        self._stats_mem_time: Dict[str, float] = {}
+        self._stats_lock = threading.Lock()
+        self._stats_dirty: set[str] = set()
+        self._stats_flush_timer: Optional[threading.Timer] = None
+        self._etag_index_dirty: set[str] = set()
+        self._etag_index_flush_timer: Optional[threading.Timer] = None
 
     def _get_bucket_lock(self, bucket_id: str) -> threading.Lock:
-        """Get or create a lock for a specific bucket. Reduces global lock contention."""
+        with self._registry_lock:
-        with self._cache_lock:
             if bucket_id not in self._bucket_locks:
                 self._bucket_locks[bucket_id] = threading.Lock()
             return self._bucket_locks[bucket_id]
@@ -260,26 +268,24 @@ class ObjectStorage:
         self._system_bucket_root(bucket_path.name).mkdir(parents=True, exist_ok=True)
 
     def bucket_stats(self, bucket_name: str, cache_ttl: int = 60) -> dict[str, int]:
-        """Return object count and total size for the bucket (cached).
-
-        Args:
-            bucket_name: Name of the bucket
-            cache_ttl: Cache time-to-live in seconds (default 60)
-        """
         bucket_path = self._bucket_path(bucket_name)
         if not bucket_path.exists():
             raise BucketNotFoundError("Bucket does not exist")
 
+        with self._stats_lock:
+            if bucket_name in self._stats_mem:
+                cached_at = self._stats_mem_time.get(bucket_name, 0.0)
+                if (time.monotonic() - cached_at) < cache_ttl:
+                    return dict(self._stats_mem[bucket_name])
+                self._stats_mem.pop(bucket_name, None)
+                self._stats_mem_time.pop(bucket_name, None)
+
         cache_path = self._system_bucket_root(bucket_name) / "stats.json"
         cached_stats = None
-        cache_fresh = False
 
         if cache_path.exists():
             try:
-                cache_fresh = time.time() - cache_path.stat().st_mtime < cache_ttl
                 cached_stats = json.loads(cache_path.read_text(encoding="utf-8"))
-                if cache_fresh:
-                    return cached_stats
             except (OSError, json.JSONDecodeError):
                 pass
 
@@ -348,16 +354,25 @@ class ObjectStorage:
             "_cache_serial": existing_serial,
         }
 
+        with self._stats_lock:
+            self._stats_mem[bucket_name] = stats
+            self._stats_mem_time[bucket_name] = time.monotonic()
+            self._stats_serial[bucket_name] = existing_serial
+
         try:
             cache_path.parent.mkdir(parents=True, exist_ok=True)
-            cache_path.write_text(json.dumps(stats), encoding="utf-8")
+            self._atomic_write_json(cache_path, stats)
         except OSError:
             pass
 
         return stats
 
     def _invalidate_bucket_stats_cache(self, bucket_id: str) -> None:
-        """Invalidate the cached bucket statistics."""
+        with self._stats_lock:
+            self._stats_mem.pop(bucket_id, None)
+            self._stats_mem_time.pop(bucket_id, None)
+            self._stats_serial[bucket_id] = self._stats_serial.get(bucket_id, 0) + 1
+            self._stats_dirty.discard(bucket_id)
         cache_path = self._system_bucket_root(bucket_id) / "stats.json"
         try:
             cache_path.unlink(missing_ok=True)
@@ -373,29 +388,52 @@ class ObjectStorage:
         version_bytes_delta: int = 0,
         version_count_delta: int = 0,
     ) -> None:
-        """Incrementally update cached bucket statistics instead of invalidating.
+        with self._stats_lock:
+            if bucket_id not in self._stats_mem:
+                self._stats_mem[bucket_id] = {
+                    "objects": 0, "bytes": 0, "version_count": 0,
+                    "version_bytes": 0, "total_objects": 0, "total_bytes": 0,
+                    "_cache_serial": 0,
+                }
+            data = self._stats_mem[bucket_id]
+            data["objects"] = max(0, data["objects"] + objects_delta)
+            data["bytes"] = max(0, data["bytes"] + bytes_delta)
+            data["version_count"] = max(0, data["version_count"] + version_count_delta)
+            data["version_bytes"] = max(0, data["version_bytes"] + version_bytes_delta)
+            data["total_objects"] = max(0, data["total_objects"] + objects_delta + version_count_delta)
+            data["total_bytes"] = max(0, data["total_bytes"] + bytes_delta + version_bytes_delta)
+            data["_cache_serial"] = data["_cache_serial"] + 1
+            self._stats_serial[bucket_id] = self._stats_serial.get(bucket_id, 0) + 1
+            self._stats_mem_time[bucket_id] = time.monotonic()
+            self._stats_dirty.add(bucket_id)
+            self._schedule_stats_flush()
 
-        This avoids expensive full directory scans on every PUT/DELETE by
+    def _schedule_stats_flush(self) -> None:
-        adjusting the cached values directly. Also signals cross-process cache
+        if self._stats_flush_timer is None or not self._stats_flush_timer.is_alive():
-        invalidation by incrementing _cache_serial.
+            self._stats_flush_timer = threading.Timer(3.0, self._flush_stats)
-        """
+            self._stats_flush_timer.daemon = True
-        cache_path = self._system_bucket_root(bucket_id) / "stats.json"
+            self._stats_flush_timer.start()
-        try:
+
-            cache_path.parent.mkdir(parents=True, exist_ok=True)
+    def _flush_stats(self) -> None:
-            if cache_path.exists():
+        with self._stats_lock:
-                data = json.loads(cache_path.read_text(encoding="utf-8"))
+            dirty = list(self._stats_dirty)
-            else:
+            self._stats_dirty.clear()
-                data = {"objects": 0, "bytes": 0, "version_count": 0, "version_bytes": 0, "total_objects": 0, "total_bytes": 0, "_cache_serial": 0}
+            snapshots = {b: dict(self._stats_mem[b]) for b in dirty if b in self._stats_mem}
-            data["objects"] = max(0, data.get("objects", 0) + objects_delta)
+        for bucket_id, data in snapshots.items():
-            data["bytes"] = max(0, data.get("bytes", 0) + bytes_delta)
+            cache_path = self._system_bucket_root(bucket_id) / "stats.json"
-            data["version_count"] = max(0, data.get("version_count", 0) + version_count_delta)
+            try:
-            data["version_bytes"] = max(0, data.get("version_bytes", 0) + version_bytes_delta)
+                cache_path.parent.mkdir(parents=True, exist_ok=True)
-            data["total_objects"] = max(0, data.get("total_objects", 0) + objects_delta + version_count_delta)
+                self._atomic_write_json(cache_path, data)
-            data["total_bytes"] = max(0, data.get("total_bytes", 0) + bytes_delta + version_bytes_delta)
+            except OSError:
-            data["_cache_serial"] = data.get("_cache_serial", 0) + 1
+                pass
-            cache_path.write_text(json.dumps(data), encoding="utf-8")
+
-        except (OSError, json.JSONDecodeError):
+    def shutdown_stats(self) -> None:
-            pass
+        if self._stats_flush_timer is not None:
+            self._stats_flush_timer.cancel()
+        self._flush_stats()
+        if self._etag_index_flush_timer is not None:
+            self._etag_index_flush_timer.cancel()
+        self._flush_etag_indexes()
 
     def delete_bucket(self, bucket_name: str) -> None:
         bucket_path = self._bucket_path(bucket_name)
@@ -413,13 +451,20 @@ class ObjectStorage:
         self._remove_tree(self._system_bucket_root(bucket_id))
         self._remove_tree(self._multipart_bucket_root(bucket_id))
         self._bucket_config_cache.pop(bucket_id, None)
-        with self._cache_lock:
+        with self._obj_cache_lock:
             self._object_cache.pop(bucket_id, None)
             self._cache_version.pop(bucket_id, None)
             self._sorted_key_cache.pop(bucket_id, None)
+        with self._meta_cache_lock:
             stale = [k for k in self._meta_read_cache if k[0] == bucket_id]
             for k in stale:
                 del self._meta_read_cache[k]
+        with self._stats_lock:
+            self._stats_mem.pop(bucket_id, None)
+            self._stats_mem_time.pop(bucket_id, None)
+            self._stats_serial.pop(bucket_id, None)
+            self._stats_dirty.discard(bucket_id)
+        self._etag_index_dirty.discard(bucket_id)
 
     def list_objects(
         self,
@@ -834,11 +879,6 @@ class ObjectStorage:
         is_overwrite = destination.exists()
         existing_size = destination.stat().st_size if is_overwrite else 0
 
-        archived_version_size = 0
-        if self._is_versioning_enabled(bucket_path) and is_overwrite:
-            archived_version_size = existing_size
-            self._archive_current_version(bucket_id, safe_key, reason="overwrite")
-
         tmp_dir = self._system_root_path() / self.SYSTEM_TMP_DIR
         tmp_dir.mkdir(parents=True, exist_ok=True)
 
@@ -865,19 +905,21 @@ class ObjectStorage:
                             quota_check["quota"],
                             quota_check["usage"],
                         )
-
+            except BaseException:
-                shutil.move(str(tmp_path), str(destination))
-            finally:
                 if tmp_path:
                     try:
                         tmp_path.unlink(missing_ok=True)
                     except OSError:
                         pass
+                raise
         else:
             tmp_path = tmp_dir / f"{uuid.uuid4().hex}.tmp"
             try:
+                checksum = hashlib.md5()
                 with tmp_path.open("wb") as target:
-                    shutil.copyfileobj(stream, target)
+                    shutil.copyfileobj(_HashingReader(stream, checksum), target)
+                    target.flush()
+                    os.fsync(target.fileno())
 
                 new_size = tmp_path.stat().st_size
                 size_delta = new_size - existing_size
@@ -896,27 +938,43 @@ class ObjectStorage:
                             quota_check["usage"],
                         )
 
-                checksum = hashlib.md5()
-                with tmp_path.open("rb") as f:
-                    while True:
-                        chunk = f.read(1048576)
-                        if not chunk:
-                            break
-                        checksum.update(chunk)
                 etag = checksum.hexdigest()
-
+            except BaseException:
-                shutil.move(str(tmp_path), str(destination))
-            finally:
                 try:
                     tmp_path.unlink(missing_ok=True)
                 except OSError:
                     pass
+                raise
 
-        stat = destination.stat()
+        lock_file_path = self._system_bucket_root(bucket_id) / "locks" / f"{safe_key.as_posix().replace('/', '_')}.lock"
+        try:
+            with _atomic_lock_file(lock_file_path):
+                archived_version_size = 0
+                if self._is_versioning_enabled(bucket_path) and is_overwrite:
+                    archived_version_size = existing_size
+                    self._archive_current_version(bucket_id, safe_key, reason="overwrite")
 
-        internal_meta = {"__etag__": etag, "__size__": str(stat.st_size)}
+                shutil.move(str(tmp_path), str(destination))
-        combined_meta = {**internal_meta, **(metadata or {})}
+                tmp_path = None
-        self._write_metadata(bucket_id, safe_key, combined_meta)
+
+                stat = destination.stat()
+
+                internal_meta = {"__etag__": etag, "__size__": str(stat.st_size), "__last_modified__": str(stat.st_mtime)}
+                combined_meta = {**internal_meta, **(metadata or {})}
+                self._write_metadata(bucket_id, safe_key, combined_meta)
+        except BlockingIOError:
+            try:
+                if tmp_path:
+                    tmp_path.unlink(missing_ok=True)
+            except OSError:
+                pass
+            raise StorageError("Another upload to this key is in progress")
+        finally:
+            if tmp_path:
+                try:
+                    tmp_path.unlink(missing_ok=True)
+                except OSError:
+                    pass
 
         self._update_bucket_stats_cache(
             bucket_id,
@@ -1508,18 +1566,16 @@ class ObjectStorage:
         temp_path = upload_root / f".{part_filename}.tmp"
 
         try:
-            with temp_path.open("wb") as target:
-                shutil.copyfileobj(stream, target)
             if _HAS_RUST:
+                with temp_path.open("wb") as target:
+                    shutil.copyfileobj(stream, target)
                 part_etag = _rc.md5_file(str(temp_path))
             else:
                 checksum = hashlib.md5()
-                with temp_path.open("rb") as f:
+                with temp_path.open("wb") as target:
-                    while True:
+                    shutil.copyfileobj(_HashingReader(stream, checksum), target)
-                        chunk = f.read(1048576)
+                    target.flush()
-                        if not chunk:
+                    os.fsync(target.fileno())
-                            break
-                        checksum.update(chunk)
                 part_etag = checksum.hexdigest()
             temp_path.replace(part_path)
         except OSError:
@@ -1553,7 +1609,7 @@ class ObjectStorage:
 
                         parts = manifest.setdefault("parts", {})
                         parts[str(part_number)] = record
-                        manifest_path.write_text(json.dumps(manifest), encoding="utf-8")
+                        self._atomic_write_json(manifest_path, manifest)
                 break
             except OSError as exc:
                 if attempt < max_retries - 1:
@@ -1646,7 +1702,7 @@ class ObjectStorage:
 
                         parts = manifest.setdefault("parts", {})
                         parts[str(part_number)] = record
-                        manifest_path.write_text(json.dumps(manifest), encoding="utf-8")
+                        self._atomic_write_json(manifest_path, manifest)
                 break
             except OSError as exc:
                 if attempt < max_retries - 1:
@@ -1752,6 +1808,8 @@ class ObjectStorage:
                                         break
                                     checksum.update(data)
                                     target.write(data)
+                        target.flush()
+                        os.fsync(target.fileno())
                     checksum_hex = checksum.hexdigest()
         except BlockingIOError:
             raise StorageError("Another upload to this key is in progress")
@@ -1770,7 +1828,7 @@ class ObjectStorage:
         etag = checksum_hex
         metadata = manifest.get("metadata")
 
-        internal_meta = {"__etag__": etag, "__size__": str(stat.st_size)}
+        internal_meta = {"__etag__": etag, "__size__": str(stat.st_size), "__last_modified__": str(stat.st_mtime)}
         combined_meta = {**internal_meta, **(metadata or {})}
         self._write_metadata(bucket_id, safe_key, combined_meta)
 
@@ -2131,19 +2189,19 @@ class ObjectStorage:
         now = time.time()
         current_stats_mtime = self._get_cache_marker_mtime(bucket_id)
 
-        with self._cache_lock:
+        with self._obj_cache_lock:
             cached = self._object_cache.get(bucket_id)
             if cached:
                 objects, timestamp, cached_stats_mtime = cached
                 if now - timestamp < self._cache_ttl and current_stats_mtime == cached_stats_mtime:
                     self._object_cache.move_to_end(bucket_id)
                     return objects
-            cache_version = self._cache_version.get(bucket_id, 0)
 
         bucket_lock = self._get_bucket_lock(bucket_id)
         with bucket_lock:
+            now = time.time()
             current_stats_mtime = self._get_cache_marker_mtime(bucket_id)
-            with self._cache_lock:
+            with self._obj_cache_lock:
                 cached = self._object_cache.get(bucket_id)
                 if cached:
                     objects, timestamp, cached_stats_mtime = cached
@@ -2154,31 +2212,23 @@ class ObjectStorage:
             objects = self._build_object_cache(bucket_path)
             new_stats_mtime = self._get_cache_marker_mtime(bucket_id)
 
-            with self._cache_lock:
+            with self._obj_cache_lock:
-                current_version = self._cache_version.get(bucket_id, 0)
-                if current_version != cache_version:
-                    objects = self._build_object_cache(bucket_path)
-                    new_stats_mtime = self._get_cache_marker_mtime(bucket_id)
                 while len(self._object_cache) >= self._object_cache_max_size:
                     self._object_cache.popitem(last=False)
 
                 self._object_cache[bucket_id] = (objects, time.time(), new_stats_mtime)
                 self._object_cache.move_to_end(bucket_id)
-                self._cache_version[bucket_id] = current_version + 1
+                self._cache_version[bucket_id] = self._cache_version.get(bucket_id, 0) + 1
                 self._sorted_key_cache.pop(bucket_id, None)
 
         return objects
 
     def _invalidate_object_cache(self, bucket_id: str) -> None:
-        """Invalidate the object cache and etag index for a bucket.
+        with self._obj_cache_lock:
-
-        Increments version counter to signal stale reads.
-        Cross-process invalidation is handled by checking stats.json mtime.
-        """
-        with self._cache_lock:
             self._object_cache.pop(bucket_id, None)
             self._cache_version[bucket_id] = self._cache_version.get(bucket_id, 0) + 1
 
+        self._etag_index_dirty.discard(bucket_id)
         etag_index_path = self._system_bucket_root(bucket_id) / "etag_index.json"
         try:
             etag_index_path.unlink(missing_ok=True)
@@ -2186,22 +2236,10 @@ class ObjectStorage:
             pass
 
     def _get_cache_marker_mtime(self, bucket_id: str) -> float:
-        """Get a cache marker combining serial and object count for cross-process invalidation.
+        return float(self._stats_serial.get(bucket_id, 0))
-
-        Returns a combined value that changes if either _cache_serial or object count changes.
-        This handles cases where the serial was reset but object count differs.
-        """
-        stats_path = self._system_bucket_root(bucket_id) / "stats.json"
-        try:
-            data = json.loads(stats_path.read_text(encoding="utf-8"))
-            serial = data.get("_cache_serial", 0)
-            count = data.get("objects", 0)
-            return float(serial * 1000000 + count)
-        except (OSError, json.JSONDecodeError):
-            return 0
 
     def _update_object_cache_entry(self, bucket_id: str, key: str, meta: Optional[ObjectMeta]) -> None:
-        with self._cache_lock:
+        with self._obj_cache_lock:
             cached = self._object_cache.get(bucket_id)
             if cached:
                 objects, timestamp, stats_mtime = cached
@@ -2212,23 +2250,32 @@ class ObjectStorage:
             self._cache_version[bucket_id] = self._cache_version.get(bucket_id, 0) + 1
             self._sorted_key_cache.pop(bucket_id, None)
 
-        self._update_etag_index(bucket_id, key, meta.etag if meta else None)
+        self._etag_index_dirty.add(bucket_id)
+        self._schedule_etag_index_flush()
 
-    def _update_etag_index(self, bucket_id: str, key: str, etag: Optional[str]) -> None:
+    def _schedule_etag_index_flush(self) -> None:
-        etag_index_path = self._system_bucket_root(bucket_id) / "etag_index.json"
+        if self._etag_index_flush_timer is None or not self._etag_index_flush_timer.is_alive():
-        if not etag_index_path.exists():
+            self._etag_index_flush_timer = threading.Timer(5.0, self._flush_etag_indexes)
-            return
+            self._etag_index_flush_timer.daemon = True
-        try:
+            self._etag_index_flush_timer.start()
-            with open(etag_index_path, 'r', encoding='utf-8') as f:
+
-                index = json.load(f)
+    def _flush_etag_indexes(self) -> None:
-            if etag is None:
+        dirty = set(self._etag_index_dirty)
-                index.pop(key, None)
+        self._etag_index_dirty.clear()
-            else:
+        for bucket_id in dirty:
-                index[key] = etag
+            with self._obj_cache_lock:
-            with open(etag_index_path, 'w', encoding='utf-8') as f:
+                cached = self._object_cache.get(bucket_id)
-                json.dump(index, f)
+                if not cached:
-        except (OSError, json.JSONDecodeError):
+                    continue
-            pass
+                objects = cached[0]
+                index = {k: v.etag for k, v in objects.items() if v.etag}
+            etag_index_path = self._system_bucket_root(bucket_id) / "etag_index.json"
+            try:
+                etag_index_path.parent.mkdir(parents=True, exist_ok=True)
+                with open(etag_index_path, 'w', encoding='utf-8') as f:
+                    json.dump(index, f)
+            except OSError:
+                pass
 
     def warm_cache(self, bucket_names: Optional[List[str]] = None) -> None:
         """Pre-warm the object cache for specified buckets or all buckets.
@@ -2269,6 +2316,23 @@ class ObjectStorage:
         ):
             path.mkdir(parents=True, exist_ok=True)
 
+    @staticmethod
+    def _atomic_write_json(path: Path, data: Any) -> None:
+        path.parent.mkdir(parents=True, exist_ok=True)
+        tmp_path = path.with_suffix(".tmp")
+        try:
+            with tmp_path.open("w", encoding="utf-8") as f:
+                json.dump(data, f)
+                f.flush()
+                os.fsync(f.fileno())
+            tmp_path.replace(path)
+        except BaseException:
+            try:
+                tmp_path.unlink(missing_ok=True)
+            except OSError:
+                pass
+            raise
+
     def _multipart_dir(self, bucket_name: str, upload_id: str) -> Path:
         return self._multipart_bucket_root(bucket_name) / upload_id
 
@@ -2285,12 +2349,7 @@ class ObjectStorage:
         if cached:
             config, cached_time, cached_mtime = cached
             if now - cached_time < self._bucket_config_cache_ttl:
-                try:
+                return config.copy()
-                    current_mtime = config_path.stat().st_mtime if config_path.exists() else 0.0
-                except OSError:
-                    current_mtime = 0.0
-                if current_mtime == cached_mtime:
-                    return config.copy()
 
         if not config_path.exists():
             self._bucket_config_cache[bucket_name] = ({}, now, 0.0)
@@ -2308,7 +2367,7 @@ class ObjectStorage:
     def _write_bucket_config(self, bucket_name: str, payload: dict[str, Any]) -> None:
         config_path = self._bucket_config_path(bucket_name)
         config_path.parent.mkdir(parents=True, exist_ok=True)
-        config_path.write_text(json.dumps(payload), encoding="utf-8")
+        self._atomic_write_json(config_path, payload)
         try:
             mtime = config_path.stat().st_mtime
         except OSError:
@@ -2342,8 +2401,7 @@ class ObjectStorage:
 
     def _write_multipart_manifest(self, upload_root: Path, manifest: dict[str, Any]) -> None:
         manifest_path = upload_root / self.MULTIPART_MANIFEST
-        manifest_path.parent.mkdir(parents=True, exist_ok=True)
+        self._atomic_write_json(manifest_path, manifest)
-        manifest_path.write_text(json.dumps(manifest), encoding="utf-8")
 
     def _metadata_file(self, bucket_name: str, key: Path) -> Path:
         meta_root = self._bucket_meta_root(bucket_name)
@@ -2359,19 +2417,19 @@ class ObjectStorage:
         return meta_root / parent / "_index.json", entry_name
 
     def _get_meta_index_lock(self, index_path: str) -> threading.Lock:
-        with self._cache_lock:
+        with self._registry_lock:
             if index_path not in self._meta_index_locks:
                 self._meta_index_locks[index_path] = threading.Lock()
             return self._meta_index_locks[index_path]
 
     def _read_index_entry(self, bucket_name: str, key: Path) -> Optional[Dict[str, Any]]:
         cache_key = (bucket_name, str(key))
-        with self._cache_lock:
+        with self._meta_cache_lock:
             hit = self._meta_read_cache.get(cache_key)
             if hit is not None:
                 self._meta_read_cache.move_to_end(cache_key)
                 cached = hit[0]
-                return copy.deepcopy(cached) if cached is not None else None
+                return dict(cached) if cached is not None else None
 
         index_path, entry_name = self._index_file_for_key(bucket_name, key)
         if _HAS_RUST:
@@ -2386,16 +2444,16 @@ class ObjectStorage:
                 except (OSError, json.JSONDecodeError):
                     result = None
 
-        with self._cache_lock:
+        with self._meta_cache_lock:
             while len(self._meta_read_cache) >= self._meta_read_cache_max:
                 self._meta_read_cache.popitem(last=False)
-            self._meta_read_cache[cache_key] = (copy.deepcopy(result) if result is not None else None,)
+            self._meta_read_cache[cache_key] = (dict(result) if result is not None else None,)
 
         return result
 
     def _invalidate_meta_read_cache(self, bucket_name: str, key: Path) -> None:
         cache_key = (bucket_name, str(key))
-        with self._cache_lock:
+        with self._meta_cache_lock:
             self._meta_read_cache.pop(cache_key, None)
 
     def _write_index_entry(self, bucket_name: str, key: Path, entry: Dict[str, Any]) -> None:
@@ -2413,7 +2471,7 @@ class ObjectStorage:
                     except (OSError, json.JSONDecodeError):
                         pass
                 index_data[entry_name] = entry
-                index_path.write_text(json.dumps(index_data), encoding="utf-8")
+                self._atomic_write_json(index_path, index_data)
         self._invalidate_meta_read_cache(bucket_name, key)
 
     def _delete_index_entry(self, bucket_name: str, key: Path) -> None:
@@ -2434,7 +2492,7 @@ class ObjectStorage:
                 if entry_name in index_data:
                     del index_data[entry_name]
                     if index_data:
-                        index_path.write_text(json.dumps(index_data), encoding="utf-8")
+                        self._atomic_write_json(index_path, index_data)
                     else:
                         try:
                             index_path.unlink()
@@ -2483,7 +2541,7 @@ class ObjectStorage:
             "reason": reason,
         }
         manifest_path = version_dir / f"{version_id}.json"
-        manifest_path.write_text(json.dumps(record), encoding="utf-8")
+        self._atomic_write_json(manifest_path, record)
 
     def _read_metadata(self, bucket_name: str, key: Path) -> Dict[str, str]:
         entry = self._read_index_entry(bucket_name, key)

app/version.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-APP_VERSION = "0.3.4"
+APP_VERSION = "0.3.6"
 
 
 def get_version() -> str:

myfsio_core/src/streaming.rs

@@ -46,6 +46,8 @@ pub fn stream_to_file_with_md5(
 
             py.check_signals()?;
         }
+        file.sync_all()
+            .map_err(|e| PyIOError::new_err(format!("Failed to fsync: {}", e)))?;
         Ok(())
     })();
 
@@ -102,6 +104,9 @@ pub fn assemble_parts_with_md5(
             }
         }
 
+        target.sync_all()
+            .map_err(|e| PyIOError::new_err(format!("Failed to fsync: {}", e)))?;
+
         Ok(format!("{:x}", hasher.finalize()))
     })
 }

static/js/bucket-detail-main.js

@@ -321,7 +321,7 @@
     `;
   };
 
-  const bucketTotalObjects = objectsContainer ? parseInt(objectsContainer.dataset.bucketTotalObjects || '0', 10) : 0;
+  let bucketTotalObjects = objectsContainer ? parseInt(objectsContainer.dataset.bucketTotalObjects || '0', 10) : 0;
 
   const updateObjectCountBadge = () => {
     if (!objectCountBadge) return;
@@ -702,6 +702,7 @@
       flushPendingStreamObjects();
       hasMoreObjects = false;
       totalObjectCount = loadedObjectCount;
+      if (!currentPrefix) bucketTotalObjects = totalObjectCount;
       updateObjectCountBadge();
 
       if (objectsLoadingRow && objectsLoadingRow.parentNode) {
@@ -766,6 +767,7 @@
       }
 
       totalObjectCount = data.total_count || 0;
+      if (!append && !currentPrefix) bucketTotalObjects = totalObjectCount;
       nextContinuationToken = data.next_continuation_token;
 
       if (!append && objectsLoadingRow) {

tests/conftest.py

@@ -43,6 +43,11 @@ def app(tmp_path: Path):
         }
     )
     yield flask_app
+    storage = flask_app.extensions.get("object_storage")
+    if storage:
+        base = getattr(storage, "storage", storage)
+        if hasattr(base, "shutdown_stats"):
+            base.shutdown_stats()
 
 
 @pytest.fixture()