fix(ecstore): skip warning for absent .minio.sys volume (#8373)

* fix(ecstore): skip warning for absent .minio.sys volume

Startup MinIO migrations read from .minio.sys and treat its absence as expected, but resolve_read_all_result logged a disk_local_read_version_fallback warning for every such read. Keep the access check and the VolumeNotFound return, and skip only the warning for the migrating metadata volume.

Refs #8372

* test(ecstore): cover .minio.sys descendants and lookalike volumes

---------

Co-authored-by: Chris <anzhengchao@gmail.com>

crates/ecstore/src/disk/local.rs

@@ -7084,14 +7084,21 @@ impl LocalDisk {
                     && let Err(access_err) = access(volume_dir).await
                     && access_err.kind() == ErrorKind::NotFound
                 {
-                    warn!(
-                        event = EVENT_DISK_LOCAL_READ_VERSION_FALLBACK,
-                        component = LOG_COMPONENT_ECSTORE,
-                        subsystem = LOG_SUBSYSTEM_DISK_LOCAL,
-                        reason = "read_all_data_with_dmtime_volume_not_found",
-                        error = ?access_err,
-                        "Disk local read fallback failed"
-                    );
+                    // An absent legacy MinIO volume is expected: startup migrations probe it.
+                    let migrating_meta = volume == super::MIGRATING_META_BUCKET
+                        || volume
+                            .strip_prefix(super::MIGRATING_META_BUCKET)
+                            .is_some_and(|rest| rest.starts_with('/'));
+                    if !migrating_meta {
+                        warn!(
+                            event = EVENT_DISK_LOCAL_READ_VERSION_FALLBACK,
+                            component = LOG_COMPONENT_ECSTORE,
+                            subsystem = LOG_SUBSYSTEM_DISK_LOCAL,
+                            reason = "read_all_data_with_dmtime_volume_not_found",
+                            error = ?access_err,
+                            "Disk local read fallback failed"
+                        );
+                    }
                     return Err(DiskError::VolumeNotFound);
                 }
 
@@ -17671,6 +17678,51 @@ mod test {
         assert!(!logs.contents().contains("reliable_rename failed"));
     }
 
+    #[tokio::test(flavor = "current_thread")]
+    async fn read_all_data_absent_migrating_meta_volume_does_not_warn() {
+        let dir = tempfile::tempdir().expect("temp dir should be created");
+        let endpoint = Endpoint::try_from(dir.path().to_str().expect("temp dir should be utf8")).expect("endpoint should parse");
+        let disk = LocalDisk::new(&endpoint, false).await.expect("local disk should be created");
+
+        let logs = CapturedLogs::default();
+        let subscriber = tracing_subscriber::fmt()
+            .with_writer(logs.clone())
+            .with_ansi(false)
+            .without_time()
+            .finish();
+        let _guard = tracing::subscriber::set_default(subscriber);
+
+        let read_absent = |volume: &str| {
+            let volume_dir = dir.path().join(volume);
+            let file_path = volume_dir
+                .join("buckets/bucket/.replication/resync.bin")
+                .join(STORAGE_FORMAT_FILE);
+            let disk = &disk;
+            let volume = volume.to_string();
+            async move { disk.read_all_data(&volume, &volume_dir, &file_path).await }
+        };
+
+        let cases = [
+            ("missing-bucket", true),
+            (".minio.sysfoo", true),
+            (super::super::MIGRATING_META_BUCKET, false),
+            (".minio.sys/buckets", false),
+        ];
+        for (volume, expect_warning) in cases {
+            logs.buffer
+                .lock()
+                .expect("captured logs mutex should not be poisoned")
+                .clear();
+            let err = read_absent(volume).await.expect_err("absent volume should fail");
+            assert!(matches!(err, DiskError::VolumeNotFound), "volume {volume}: {err:?}");
+            assert_eq!(
+                logs.contents().contains("read_all_data_with_dmtime_volume_not_found"),
+                expect_warning,
+                "volume {volume}"
+            );
+        }
+    }
+
     #[tokio::test(flavor = "current_thread")]
     async fn test_delete_versions_missing_inline_data_dir_does_not_warn() {
         use tempfile::tempdir;