feat(tier): inspect legacy transition state safely

crates/ecstore/src/api/mod.rs

@@ -37,6 +37,16 @@ pub mod bucket {
     }
 
     pub mod lifecycle {
+        pub mod legacy_transition_state_reconcile {
+            pub use crate::bucket::lifecycle::legacy_transition_state_reconcile::{
+                LegacyTransitionStateCopyRepresentation, LegacyTransitionStateMetadataAlias, LegacyTransitionStateReconcileError,
+                LegacyTransitionStateReconcileOutcome, LegacyTransitionStateReconcileReadiness,
+                LegacyTransitionStateReconcileRequest, LegacyTransitionStateReconcileResponse,
+                LegacyTransitionStateReconcileSelector, LegacyTransitionStateSetRepresentation, LegacyTransitionStateSource,
+                LegacyTransitionStateTarget,
+            };
+        }
+
         pub mod bucket_lifecycle_audit {
             pub use crate::bucket::lifecycle::bucket_lifecycle_audit::LcEventSrc;
         }

crates/ecstore/src/bucket/lifecycle/bucket_lifecycle_ops.rs

@@ -589,33 +589,192 @@ impl ExpiryOp for FreeVersionTask {
     }
 }
 
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+enum TransitionDeleteVersionPlan {
+    Direct { version_id_exact: bool },
+    ProbeLegacyUnknown,
+}
+
+fn legacy_transition_version_state_missing(oi: &ObjectInfo) -> Result<bool, std::io::Error> {
+    use rustfs_utils::http::metadata_compat::{
+        SUFFIX_TRANSITIONED_VERSION_ID, SUFFIX_TRANSITIONED_VERSION_STATE, contains_key_str, get_consistent_str,
+    };
+
+    if !contains_key_str(&oi.user_defined, SUFFIX_TRANSITIONED_VERSION_STATE) {
+        let version_key_present = contains_key_str(&oi.user_defined, SUFFIX_TRANSITIONED_VERSION_ID);
+        if version_key_present {
+            if oi.transitioned_object.version_id.is_empty() {
+                let has_non_empty_version = oi.user_defined.iter().any(|(key, value)| {
+                    rustfs_utils::http::metadata_compat::strip_internal_prefix_preserving_case(key)
+                        .is_some_and(|suffix| suffix.eq_ignore_ascii_case(SUFFIX_TRANSITIONED_VERSION_ID))
+                        && !value.is_empty()
+                });
+                if !has_non_empty_version {
+                    // MinIO writes the transitioned-versionID key with an empty value
+                    // for unversioned tier objects. The backend probe remains the proof.
+                    return Ok(true);
+                }
+            } else if get_consistent_str(&oi.user_defined, SUFFIX_TRANSITIONED_VERSION_ID)
+                == Some(oi.transitioned_object.version_id.as_str())
+            {
+                return Ok(true);
+            }
+            return Err(std::io::Error::new(
+                std::io::ErrorKind::InvalidData,
+                "legacy remote tier version metadata is conflicting or malformed",
+            ));
+        }
+        if !oi.transitioned_object.version_id.is_empty() {
+            return Err(std::io::Error::new(
+                std::io::ErrorKind::InvalidData,
+                "legacy remote tier version metadata is missing or inconsistent",
+            ));
+        }
+        return Ok(true);
+    }
+    let persisted = get_consistent_str(&oi.user_defined, SUFFIX_TRANSITIONED_VERSION_STATE).ok_or_else(|| {
+        std::io::Error::new(
+            std::io::ErrorKind::InvalidData,
+            "remote tier object has conflicting transition version state metadata",
+        )
+    })?;
+    if persisted != oi.transition_version_state.as_str() {
+        return Err(std::io::Error::new(
+            std::io::ErrorKind::InvalidData,
+            "remote tier object transition version state metadata changed during decoding",
+        ));
+    }
+    Ok(false)
+}
+
+fn transition_remote_version_delete_plan(oi: &ObjectInfo) -> Result<TransitionDeleteVersionPlan, std::io::Error> {
+    match oi.transition_version_state {
+        rustfs_filemeta::TransitionVersionState::Unknown => {
+            if legacy_transition_version_state_missing(oi)? {
+                Ok(TransitionDeleteVersionPlan::ProbeLegacyUnknown)
+            } else {
+                validate_transition_remote_version(oi)
+                    .map(|version_id_exact| TransitionDeleteVersionPlan::Direct { version_id_exact })
+            }
+        }
+        _ => validate_transition_remote_version(oi)
+            .map(|version_id_exact| TransitionDeleteVersionPlan::Direct { version_id_exact }),
+    }
+}
+
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+struct ResolvedTransitionDeleteVersion {
+    version_id_exact: bool,
+    verify_missing_after_delete: bool,
+    remote_already_missing: bool,
+}
+
 async fn acquire_free_version_tier_lease(
     oi: &ObjectInfo,
     tier_config_mgr: &Arc<RwLock<TierConfigMgr>>,
-) -> Result<(TierOperationLease, bool), std::io::Error> {
-    let version_id_exact = validate_transition_remote_version(oi)?;
+) -> Result<(TierOperationLease, TransitionDeleteVersionPlan), std::io::Error> {
+    let delete_plan = transition_remote_version_delete_plan(oi)?;
     let identity = tier_destination_id_from_metadata(&oi.user_defined)?
         .ok_or_else(|| std::io::Error::other("tier free-version has no durable backend identity"))?;
     let lease =
         TierConfigMgr::acquire_operation_lease_for_backend_identity(tier_config_mgr, &oi.transitioned_object.tier, identity)
             .await
             .map_err(std::io::Error::other)?;
-    Ok((lease, version_id_exact))
+    Ok((lease, delete_plan))
+}
+
+async fn resolve_transition_delete_version_plan(
+    oi: &ObjectInfo,
+    lease: &TierOperationLease,
+    delete_plan: TransitionDeleteVersionPlan,
+) -> Result<ResolvedTransitionDeleteVersion, std::io::Error> {
+    match delete_plan {
+        TransitionDeleteVersionPlan::Direct { version_id_exact } => Ok(ResolvedTransitionDeleteVersion {
+            version_id_exact,
+            verify_missing_after_delete: false,
+            remote_already_missing: false,
+        }),
+        TransitionDeleteVersionPlan::ProbeLegacyUnknown => {
+            let probe = lease.probe_transition_candidate(&oi.transitioned_object.name).await?;
+            match (oi.transitioned_object.version_id.as_str(), probe) {
+                ("", crate::services::tier::warm_backend::TransitionCandidateProbe::UnversionedPresent) => {
+                    Ok(ResolvedTransitionDeleteVersion {
+                        version_id_exact: false,
+                        verify_missing_after_delete: true,
+                        remote_already_missing: false,
+                    })
+                }
+                (expected, crate::services::tier::warm_backend::TransitionCandidateProbe::VersionedPresent(actual))
+                    if !expected.is_empty() && expected == actual =>
+                {
+                    lease.validate_remote_version_id(expected)?;
+                    Ok(ResolvedTransitionDeleteVersion {
+                        version_id_exact: true,
+                        verify_missing_after_delete: false,
+                        remote_already_missing: false,
+                    })
+                }
+                ("null", crate::services::tier::warm_backend::TransitionCandidateProbe::SuspendedNullPresent) => {
+                    lease.validate_remote_version_id("null")?;
+                    Ok(ResolvedTransitionDeleteVersion {
+                        version_id_exact: true,
+                        verify_missing_after_delete: false,
+                        remote_already_missing: false,
+                    })
+                }
+                (_, crate::services::tier::warm_backend::TransitionCandidateProbe::Missing) => {
+                    Ok(ResolvedTransitionDeleteVersion {
+                        version_id_exact: false,
+                        verify_missing_after_delete: false,
+                        remote_already_missing: true,
+                    })
+                }
+                (_, crate::services::tier::warm_backend::TransitionCandidateProbe::Unsupported) => Err(std::io::Error::new(
+                    std::io::ErrorKind::Unsupported,
+                    "remote tier cannot prove legacy transition delete state",
+                )),
+                _ => Err(std::io::Error::new(
+                    std::io::ErrorKind::WouldBlock,
+                    "remote tier object version state is unknown",
+                )),
+            }
+        }
+    }
+}
+
+async fn execute_resolved_transition_delete(
+    oi: &ObjectInfo,
+    lease: &TierOperationLease,
+    resolved: ResolvedTransitionDeleteVersion,
+) -> Result<(), std::io::Error> {
+    if !resolved.remote_already_missing {
+        delete_object_from_remote_tier_with_lease_idempotent(
+            &oi.transitioned_object.name,
+            &oi.transitioned_object.version_id,
+            lease,
+            resolved.version_id_exact,
+        )
+        .await?;
+    }
+    if resolved.verify_missing_after_delete
+        && lease.probe_transition_candidate(&oi.transitioned_object.name).await?
+            != crate::services::tier::warm_backend::TransitionCandidateProbe::Missing
+    {
+        return Err(std::io::Error::new(
+            std::io::ErrorKind::WouldBlock,
+            "remote tier could not confirm legacy unversioned deletion",
+        ));
+    }
+    Ok(())
 }
 
 async fn delete_free_version_remote_object_with_lease(
     oi: &ObjectInfo,
     lease: &TierOperationLease,
-    version_id_exact: bool,
+    delete_plan: TransitionDeleteVersionPlan,
 ) -> Result<(), std::io::Error> {
-    delete_object_from_remote_tier_with_lease_idempotent(
-        &oi.transitioned_object.name,
-        &oi.transitioned_object.version_id,
-        lease,
-        version_id_exact,
-    )
-    .await?;
-    Ok(())
+    let resolved = resolve_transition_delete_version_plan(oi, lease, delete_plan).await?;
+    execute_resolved_transition_delete(oi, lease, resolved).await
 }
 
 fn free_version_physical_topology_generation(api: &ECStore) -> String {
@@ -646,6 +805,16 @@ fn free_version_remote_tuple_matches(candidate: &ObjectInfo, expected: &ObjectIn
     if candidate.transition_version_state == rustfs_filemeta::TransitionVersionState::Unknown
         || expected.transition_version_state == rustfs_filemeta::TransitionVersionState::Unknown
     {
+        let candidate_legacy_missing = legacy_transition_version_state_missing(candidate)?;
+        let expected_legacy_missing = legacy_transition_version_state_missing(expected)?;
+        if candidate.transition_version_state == rustfs_filemeta::TransitionVersionState::Unknown
+            && expected.transition_version_state == rustfs_filemeta::TransitionVersionState::Unknown
+            && candidate_legacy_missing
+            && expected_legacy_missing
+            && candidate.transitioned_object.version_id == expected.transitioned_object.version_id
+        {
+            return Ok(true);
+        }
         return Err(std::io::Error::new(
             std::io::ErrorKind::WouldBlock,
             "tier free-version remote version state is unknown",
@@ -721,7 +890,7 @@ async fn cleanup_free_version_exact(api: Arc<ECStore>, oi: &ObjectInfo, cancel:
         .acquire_bucket_lifecycle_read_lock(&oi.bucket)
         .await
         .map_err(std::io::Error::other)?;
-    let (lease, version_id_exact) = acquire_free_version_tier_lease(oi, &api.tier_config_mgr()).await?;
+    let (lease, delete_plan) = acquire_free_version_tier_lease(oi, &api.tier_config_mgr()).await?;
     let local_object = encode_dir_object(&oi.name);
     let object_guards = api
         .acquire_all_physical_object_write_locks("tier_free_version_cleanup", &oi.bucket, &local_object)
@@ -739,16 +908,30 @@ async fn cleanup_free_version_exact(api: Arc<ECStore>, oi: &ObjectInfo, cancel:
             "tier free-version cleanup fence is invalid before remote delete",
         ));
     }
+    let resolved = tokio::select! {
+        _ = cancel.cancelled() => {
+            return Err(std::io::Error::new(std::io::ErrorKind::Interrupted, "tier free-version cleanup was cancelled"));
+        }
+        result = tokio::time::timeout_at(deadline, resolve_transition_delete_version_plan(oi, &lease, delete_plan)) => {
+            result.map_err(|_| {
+                std::io::Error::new(std::io::ErrorKind::TimedOut, "tier free-version remote probe timed out")
+            })??
+        }
+    };
+    if !free_version_cleanup_fences_current(&topology_generation, &api, &bucket_guard, &object_guards, &lease, cancel, deadline) {
+        return Err(std::io::Error::new(
+            std::io::ErrorKind::WouldBlock,
+            "tier free-version cleanup fence changed after remote probe",
+        ));
+    }
     tokio::select! {
         _ = cancel.cancelled() => {
             return Err(std::io::Error::new(std::io::ErrorKind::Interrupted, "tier free-version cleanup was cancelled"));
         }
-        result = tokio::time::timeout_at(
-            deadline,
-            delete_free_version_remote_object_with_lease(oi, &lease, version_id_exact),
-        ) => {
-            result
-                .map_err(|_| std::io::Error::new(std::io::ErrorKind::TimedOut, "tier free-version remote delete timed out"))??;
+        result = tokio::time::timeout_at(deadline, execute_resolved_transition_delete(oi, &lease, resolved)) => {
+            result.map_err(|_| {
+                std::io::Error::new(std::io::ErrorKind::TimedOut, "tier free-version remote delete timed out")
+            })??;
         }
     }
     if !free_version_cleanup_fences_current(&topology_generation, &api, &bucket_guard, &object_guards, &lease, cancel, deadline) {
@@ -796,8 +979,8 @@ async fn delete_free_version_remote_object(
     oi: &ObjectInfo,
     tier_config_mgr: &Arc<RwLock<TierConfigMgr>>,
 ) -> Result<(), std::io::Error> {
-    let (lease, version_id_exact) = acquire_free_version_tier_lease(oi, tier_config_mgr).await?;
-    delete_free_version_remote_object_with_lease(oi, &lease, version_id_exact).await
+    let (lease, delete_plan) = acquire_free_version_tier_lease(oi, tier_config_mgr).await?;
+    delete_free_version_remote_object_with_lease(oi, &lease, delete_plan).await
 }
 
 #[allow(
@@ -813,8 +996,8 @@ where
     F: FnOnce() -> Fut,
     Fut: std::future::Future<Output = T>,
 {
-    let (lease, version_id_exact) = acquire_free_version_tier_lease(oi, tier_config_mgr).await?;
-    delete_free_version_remote_object_with_lease(oi, &lease, version_id_exact).await?;
+    let (lease, delete_plan) = acquire_free_version_tier_lease(oi, tier_config_mgr).await?;
+    delete_free_version_remote_object_with_lease(oi, &lease, delete_plan).await?;
     let result = delete_local().await;
     drop(lease);
     Ok(result)
@@ -4693,6 +4876,39 @@ fn validate_transition_remote_version(oi: &ObjectInfo) -> Result<bool, std::io::
     }
 }
 
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+enum TransitionReadVersionPlan {
+    Direct,
+    ProbeLegacyUnversioned,
+}
+
+const LEGACY_TRANSITION_READ_PROBE_TIMEOUT: StdDuration = StdDuration::from_secs(30);
+
+fn transition_remote_version_read_plan(oi: &ObjectInfo) -> Result<TransitionReadVersionPlan, std::io::Error> {
+    let version = oi.transitioned_object.version_id.as_str();
+    match oi.transition_version_state {
+        rustfs_filemeta::TransitionVersionState::Unknown => {
+            if !legacy_transition_version_state_missing(oi)? {
+                return validate_transition_remote_version(oi).map(|_| TransitionReadVersionPlan::Direct);
+            }
+            if version.is_empty() {
+                Ok(TransitionReadVersionPlan::ProbeLegacyUnversioned)
+            } else {
+                Ok(TransitionReadVersionPlan::Direct)
+            }
+        }
+        rustfs_filemeta::TransitionVersionState::KnownDisabled if version.is_empty() => Ok(TransitionReadVersionPlan::Direct),
+        rustfs_filemeta::TransitionVersionState::SuspendedNull if version == "null" => Ok(TransitionReadVersionPlan::Direct),
+        rustfs_filemeta::TransitionVersionState::Exact if !version.is_empty() && version != "null" => {
+            Ok(TransitionReadVersionPlan::Direct)
+        }
+        _ => Err(std::io::Error::new(
+            std::io::ErrorKind::InvalidData,
+            "remote tier object version state conflicts with its version ID",
+        )),
+    }
+}
+
 // The resolver joins the tier manager as the second injected port this read
 // needs; grouping the request half into a struct would churn every call site of
 // a bug fix.
@@ -4707,7 +4923,12 @@ pub(crate) async fn get_transitioned_object_reader_with_tier_manager(
     tier_config_mgr: &Arc<RwLock<TierConfigMgr>>,
     resolver: Option<&dyn ObjectEncryptionResolver>,
 ) -> Result<GetObjectReader, std::io::Error> {
-    validate_transition_remote_version(oi)?;
+    let read_plan = transition_remote_version_read_plan(oi)?;
+    // Reject invalid ranges and encryption requests before a compatibility
+    // probe can amplify them into remote listing work.
+    let plan = ReadPlan::build_for_request(rs.clone(), oi, opts, h, resolver)
+        .await
+        .map_err(|err| std::io::Error::other(format!("building the read plan for {bucket}/{object} failed: {err}")))?;
     let expected_identity = tier_destination_id_from_metadata(&oi.user_defined)?;
     let lease = match expected_identity {
         Some(identity) => {
@@ -4721,7 +4942,36 @@ pub(crate) async fn get_transitioned_object_reader_with_tier_manager(
         Err(err) => return Err(std::io::Error::other(err)),
     };
 
-    tgt_client.validate_remote_version_id(&oi.transitioned_object.version_id)?;
+    match read_plan {
+        TransitionReadVersionPlan::Direct => {
+            tgt_client.validate_remote_version_id(&oi.transitioned_object.version_id)?;
+        }
+        TransitionReadVersionPlan::ProbeLegacyUnversioned => {
+            // RUSTFS_COMPAT_TODO(backlog#2203): remove operation-time probing
+            // after an admin reconcile can persist every proven legacy state.
+            let probe = tokio::time::timeout(
+                LEGACY_TRANSITION_READ_PROBE_TIMEOUT,
+                tgt_client.probe_transition_candidate(&oi.transitioned_object.name),
+            )
+            .await
+            .map_err(|_| std::io::Error::new(std::io::ErrorKind::TimedOut, "legacy remote tier version probe timed out"))??;
+            match probe {
+                crate::services::tier::warm_backend::TransitionCandidateProbe::UnversionedPresent => {}
+                crate::services::tier::warm_backend::TransitionCandidateProbe::Unsupported => {
+                    return Err(std::io::Error::new(
+                        std::io::ErrorKind::Unsupported,
+                        "remote tier cannot prove legacy unversioned transition state",
+                    ));
+                }
+                _ => {
+                    return Err(std::io::Error::new(
+                        std::io::ErrorKind::InvalidData,
+                        "remote tier object version state is unknown",
+                    ));
+                }
+            }
+        }
+    }
 
     // The same read plan the local path uses, so the tier fetch is positioned in
     // the object's *stored* coordinate system and the stream is handed the same
@@ -4729,9 +4979,6 @@ pub(crate) async fn get_transitioned_object_reader_with_tier_manager(
     // through a plaintext-coordinate range and skipping the transform is how a
     // transitioned SSE object used to come back as silently corrupt bytes of the
     // right length (rustfs/rustfs#6025).
-    let plan = ReadPlan::build_for_request(rs.clone(), oi, opts, h, resolver)
-        .await
-        .map_err(|err| std::io::Error::other(format!("building the read plan for {bucket}/{object} failed: {err}")))?;
     let (off, length) = (plan.storage_offset() as i64, plan.storage_length());
     let mut gopts = WarmBackendGetOpts::default();
 
@@ -5629,11 +5876,13 @@ mod tests {
     use crate::layout::endpoints::{EndpointServerPools, Endpoints, PoolEndpoints};
     use crate::object_api::{ObjectInfo, ObjectOptions, PutObjReader};
     #[cfg(feature = "test-util")]
+    use crate::services::tier::test_util::MockWarmOp;
+    #[cfg(feature = "test-util")]
     use crate::services::tier::test_util::register_mock_tier;
     #[cfg(feature = "test-util")]
     use crate::services::tier::tier::TierConfigMgr;
     #[cfg(feature = "test-util")]
-    use crate::services::tier::warm_backend::WarmBackend as _;
+    use crate::services::tier::warm_backend::{TransitionCandidateProbe, WarmBackend as _};
     use crate::set_disk::{MultipartCommitBarrier, MultipartCommitPause};
     use crate::set_disk::{RUSTFS_MULTIPART_BUCKET_KEY, RUSTFS_MULTIPART_OBJECT_KEY};
     use crate::storage_api_contracts::namespace::NamespaceLocking as _;
@@ -6329,7 +6578,75 @@ mod tests {
 
     #[cfg(feature = "test-util")]
     #[tokio::test]
-    async fn transitioned_get_rejects_unknown_version_state_before_backend_io() {
+    async fn transitioned_get_allows_legacy_unknown_exact_version_for_non_destructive_read() {
+        let manager = TierConfigMgr::new();
+        let tier = format!("COLDTIER{}", &Uuid::new_v4().simple().to_string()[..8]).to_uppercase();
+        let backend = register_mock_tier(&manager, &tier).await;
+        let remote_object = format!("remote/{}", Uuid::new_v4());
+        let body = Bytes::from_static(b"legacy transitioned object body");
+        let remote_version = backend
+            .put(
+                &remote_object,
+                ReaderImpl::Body(body.clone()),
+                i64::try_from(body.len()).expect("body length should fit"),
+            )
+            .await
+            .expect("mock remote object should be stored");
+        let mut user_defined = HashMap::new();
+        insert_legacy_transition_version_id(&mut user_defined, &remote_version);
+        let object_info = ObjectInfo {
+            bucket: "bucket".to_string(),
+            name: "object".to_string(),
+            size: i64::try_from(body.len()).expect("body length should fit"),
+            transitioned_object: TransitionedObject {
+                name: remote_object,
+                version_id: remote_version,
+                status: crate::bucket::lifecycle::lifecycle::TRANSITION_COMPLETE.to_string(),
+                tier: tier.clone(),
+                ..Default::default()
+            },
+            transition_version_state: rustfs_filemeta::TransitionVersionState::Unknown,
+            user_defined: user_defined.into(),
+            ..Default::default()
+        };
+
+        let range = Some(crate::storage_api_contracts::range::HTTPRangeSpec {
+            is_suffix_length: false,
+            start: 7,
+            end: 18,
+        });
+        let mut reader = get_transitioned_object_reader_with_tier_manager(
+            &object_info.bucket,
+            &object_info.name,
+            &range,
+            &HeaderMap::new(),
+            &object_info,
+            &ObjectOptions::default(),
+            &manager,
+            None,
+        )
+        .await
+        .expect("legacy unknown state should still allow a non-destructive read");
+        let mut got = Vec::new();
+        reader
+            .stream
+            .read_to_end(&mut got)
+            .await
+            .expect("transitioned reader should drain");
+
+        assert_eq!(got, &body.as_ref()[7..=18]);
+        assert_eq!(backend.get_count().await, 1);
+        assert_eq!(backend.remove_count().await, 0);
+        assert_eq!(
+            TierConfigMgr::active_operation_lease_count(&manager, &tier).await,
+            0,
+            "tier generation lease should release after EOF"
+        );
+    }
+
+    #[cfg(feature = "test-util")]
+    #[tokio::test]
+    async fn transitioned_get_rejects_explicit_unknown_version_state_before_backend_io() {
         let manager = TierConfigMgr::new();
         let tier = format!("COLDTIER{}", &Uuid::new_v4().simple().to_string()[..8]).to_uppercase();
         let backend = register_mock_tier(&manager, &tier).await;
@@ -6345,6 +6662,181 @@ mod tests {
                 ..Default::default()
             },
             transition_version_state: rustfs_filemeta::TransitionVersionState::Unknown,
+            user_defined: user_defined_with_transition_version_state(rustfs_filemeta::TransitionVersionState::Unknown).into(),
+            ..Default::default()
+        };
+
+        let err = match get_transitioned_object_reader_with_tier_manager(
+            &object_info.bucket,
+            &object_info.name,
+            &None,
+            &HeaderMap::new(),
+            &object_info,
+            &ObjectOptions::default(),
+            &manager,
+            None,
+        )
+        .await
+        {
+            Ok(_) => panic!("explicit unknown remote version state must fail before backend IO"),
+            Err(err) => err,
+        };
+
+        assert_eq!(err.kind(), std::io::ErrorKind::InvalidData);
+        assert_eq!(backend.op_log().await, Vec::<MockWarmOp>::new());
+        assert_eq!(backend.get_count().await, 0);
+    }
+
+    #[cfg(feature = "test-util")]
+    #[tokio::test]
+    async fn transitioned_get_rejects_present_but_invalid_legacy_version_metadata() {
+        let manager = TierConfigMgr::new();
+        let tier = format!("COLDTIER{}", &Uuid::new_v4().simple().to_string()[..8]).to_uppercase();
+        let backend = register_mock_tier(&manager, &tier).await;
+
+        for persisted_version in [
+            Uuid::nil().to_string(),
+            "\u{fffd}".to_string(),
+            "bad\u{0001}version".to_string(),
+        ] {
+            let mut user_defined = HashMap::new();
+            insert_legacy_transition_version_id(&mut user_defined, &persisted_version);
+            let object_info = ObjectInfo {
+                bucket: "bucket".to_string(),
+                name: "object".to_string(),
+                size: 1,
+                transitioned_object: TransitionedObject {
+                    name: "remote/object".to_string(),
+                    version_id: String::new(),
+                    status: crate::bucket::lifecycle::lifecycle::TRANSITION_COMPLETE.to_string(),
+                    tier: tier.clone(),
+                    ..Default::default()
+                },
+                transition_version_state: rustfs_filemeta::TransitionVersionState::Unknown,
+                user_defined: user_defined.into(),
+                ..Default::default()
+            };
+
+            let err = match get_transitioned_object_reader_with_tier_manager(
+                &object_info.bucket,
+                &object_info.name,
+                &None,
+                &HeaderMap::new(),
+                &object_info,
+                &ObjectOptions::default(),
+                &manager,
+                None,
+            )
+            .await
+            {
+                Ok(_) => panic!("present but invalid legacy version metadata must fail before backend IO"),
+                Err(err) => err,
+            };
+
+            assert_eq!(err.kind(), std::io::ErrorKind::InvalidData);
+        }
+
+        assert_eq!(backend.op_log().await, Vec::<MockWarmOp>::new());
+    }
+
+    #[cfg(feature = "test-util")]
+    #[tokio::test]
+    async fn transitioned_get_probes_legacy_empty_unknown_state_before_unversioned_read() {
+        let manager = TierConfigMgr::new();
+        let tier = format!("COLDTIER{}", &Uuid::new_v4().simple().to_string()[..8]).to_uppercase();
+        let backend = register_mock_tier(&manager, &tier).await;
+        backend.set_put_remote_version(Some(String::new())).await;
+        let remote_object = format!("remote/{}", Uuid::new_v4());
+        let body = Bytes::from_static(b"legacy unversioned transitioned object body");
+        let remote_version = backend
+            .put(
+                &remote_object,
+                ReaderImpl::Body(body.clone()),
+                i64::try_from(body.len()).expect("body length should fit"),
+            )
+            .await
+            .expect("mock remote object should be stored");
+        assert!(remote_version.is_empty());
+        let object_info = ObjectInfo {
+            bucket: "bucket".to_string(),
+            name: "object".to_string(),
+            size: i64::try_from(body.len()).expect("body length should fit"),
+            transitioned_object: TransitionedObject {
+                name: remote_object.clone(),
+                version_id: String::new(),
+                status: crate::bucket::lifecycle::lifecycle::TRANSITION_COMPLETE.to_string(),
+                tier: tier.clone(),
+                ..Default::default()
+            },
+            transition_version_state: rustfs_filemeta::TransitionVersionState::Unknown,
+            user_defined: HashMap::from([("x-minio-internal-transitioned-versionID".to_string(), String::new())]).into(),
+            ..Default::default()
+        };
+
+        let mut reader = get_transitioned_object_reader_with_tier_manager(
+            &object_info.bucket,
+            &object_info.name,
+            &None,
+            &HeaderMap::new(),
+            &object_info,
+            &ObjectOptions::default(),
+            &manager,
+            None,
+        )
+        .await
+        .expect("probe-proven legacy unversioned state should allow a non-destructive read");
+        let mut got = Vec::new();
+        reader
+            .stream
+            .read_to_end(&mut got)
+            .await
+            .expect("transitioned reader should drain");
+
+        assert_eq!(got, body.as_ref());
+        assert_eq!(backend.remove_count().await, 0);
+        assert_eq!(
+            backend.op_log().await,
+            vec![
+                MockWarmOp::Put {
+                    object: remote_object.clone()
+                },
+                MockWarmOp::Probe {
+                    object: remote_object.clone()
+                },
+                MockWarmOp::Get { object: remote_object },
+            ]
+        );
+        assert_eq!(
+            TierConfigMgr::active_operation_lease_count(&manager, &tier).await,
+            0,
+            "tier generation lease should release after EOF"
+        );
+    }
+
+    #[cfg(feature = "test-util")]
+    #[tokio::test]
+    async fn transitioned_get_rejects_ambiguous_empty_unknown_state_without_backend_get() {
+        let manager = TierConfigMgr::new();
+        let tier = format!("COLDTIER{}", &Uuid::new_v4().simple().to_string()[..8]).to_uppercase();
+        let backend = register_mock_tier(&manager, &tier).await;
+        let remote_object = format!("remote/{}", Uuid::new_v4());
+        backend
+            .set_transition_candidate_probe_override(Some(TransitionCandidateProbe::VersionedPresent(
+                "versioned-candidate".to_string(),
+            )))
+            .await;
+        let object_info = ObjectInfo {
+            bucket: "bucket".to_string(),
+            name: "object".to_string(),
+            size: 1,
+            transitioned_object: TransitionedObject {
+                name: remote_object.clone(),
+                version_id: String::new(),
+                status: crate::bucket::lifecycle::lifecycle::TRANSITION_COMPLETE.to_string(),
+                tier,
+                ..Default::default()
+            },
+            transition_version_state: rustfs_filemeta::TransitionVersionState::Unknown,
             ..Default::default()
         };
 
@@ -6360,19 +6852,28 @@ mod tests {
         )
         .await
         {
-            Ok(_) => panic!("unknown remote version state must fail before backend IO"),
+            Ok(_) => panic!("versioned legacy unknown state without stored version must fail before backend GET"),
             Err(err) => err,
         };
 
         assert_eq!(err.kind(), std::io::ErrorKind::InvalidData);
+        assert_eq!(backend.op_log().await, vec![MockWarmOp::Probe { object: remote_object }]);
         assert_eq!(backend.get_count().await, 0);
+        assert_eq!(backend.remove_count().await, 0);
     }
 
     #[cfg(feature = "test-util")]
     #[tokio::test]
-    async fn free_version_delete_rejects_unknown_version_state_before_backend_io() {
+    async fn free_version_delete_rejects_explicit_unknown_before_backend_io() {
         let manager = TierConfigMgr::new();
         let backend = register_mock_tier(&manager, "WARM").await;
+        let identity = test_tier_destination_identity(&manager, "WARM").await;
+        let mut user_defined = user_defined_with_tier_destination_identity(identity);
+        rustfs_utils::http::metadata_compat::insert_str(
+            &mut user_defined,
+            rustfs_utils::http::metadata_compat::SUFFIX_TRANSITIONED_VERSION_STATE,
+            rustfs_filemeta::TransitionVersionState::Unknown.as_str().to_string(),
+        );
         let object_info = ObjectInfo {
             transitioned_object: TransitionedObject {
                 name: "remote/object".to_string(),
@@ -6381,14 +6882,243 @@ mod tests {
                 ..Default::default()
             },
             transition_version_state: rustfs_filemeta::TransitionVersionState::Unknown,
+            user_defined: user_defined.into(),
             ..Default::default()
         };
 
         let err = super::delete_free_version_remote_object(&object_info, &manager)
             .await
-            .expect_err("unknown remote version state must fail before backend IO");
+            .expect_err("explicit unknown cleanup must fail before backend IO");
 
         assert_eq!(err.kind(), std::io::ErrorKind::InvalidData);
+        assert!(err.to_string().contains("version state is unknown"));
+        assert_eq!(backend.op_log().await, Vec::<MockWarmOp>::new());
+        assert_eq!(backend.remove_count().await, 0);
+    }
+
+    #[cfg(feature = "test-util")]
+    async fn test_tier_destination_identity(
+        manager: &Arc<tokio::sync::RwLock<TierConfigMgr>>,
+        tier: &str,
+    ) -> crate::services::tier::tier::TierDestinationId {
+        TierConfigMgr::acquire_operation_lease(manager, tier)
+            .await
+            .expect("test tier lease should be available")
+            .backend_identity()
+    }
+
+    #[cfg(feature = "test-util")]
+    fn user_defined_with_tier_destination_identity(
+        identity: crate::services::tier::tier::TierDestinationId,
+    ) -> HashMap<String, String> {
+        let mut user_defined = HashMap::new();
+        rustfs_utils::http::metadata_compat::insert_str(
+            &mut user_defined,
+            rustfs_utils::http::metadata_compat::SUFFIX_TRANSITION_TIER_DESTINATION_ID,
+            rustfs_utils::crypto::hex(identity),
+        );
+        user_defined
+    }
+
+    #[cfg(feature = "test-util")]
+    fn user_defined_with_transition_version_state(state: rustfs_filemeta::TransitionVersionState) -> HashMap<String, String> {
+        let mut user_defined = HashMap::new();
+        rustfs_utils::http::metadata_compat::insert_str(
+            &mut user_defined,
+            rustfs_utils::http::metadata_compat::SUFFIX_TRANSITIONED_VERSION_STATE,
+            state.as_str().to_string(),
+        );
+        user_defined
+    }
+
+    #[cfg(feature = "test-util")]
+    fn insert_legacy_transition_version_id(user_defined: &mut HashMap<String, String>, version_id: &str) {
+        rustfs_utils::http::metadata_compat::insert_str(
+            user_defined,
+            rustfs_utils::http::metadata_compat::SUFFIX_TRANSITIONED_VERSION_ID,
+            version_id.to_string(),
+        );
+    }
+
+    #[cfg(feature = "test-util")]
+    #[tokio::test]
+    async fn free_version_tuple_rejects_mixed_legacy_missing_and_explicit_unknown() {
+        let manager = TierConfigMgr::new();
+        register_mock_tier(&manager, "WARM").await;
+        let identity = test_tier_destination_identity(&manager, "WARM").await;
+        let mut legacy_metadata = user_defined_with_tier_destination_identity(identity);
+        insert_legacy_transition_version_id(&mut legacy_metadata, "legacy-version");
+        let mut explicit_metadata = legacy_metadata.clone();
+        rustfs_utils::http::metadata_compat::insert_str(
+            &mut explicit_metadata,
+            rustfs_utils::http::metadata_compat::SUFFIX_TRANSITIONED_VERSION_STATE,
+            rustfs_filemeta::TransitionVersionState::Unknown.as_str().to_string(),
+        );
+        let make_info = |user_defined: HashMap<String, String>| ObjectInfo {
+            transitioned_object: TransitionedObject {
+                name: "remote/object".to_string(),
+                version_id: "legacy-version".to_string(),
+                tier: "WARM".to_string(),
+                ..Default::default()
+            },
+            transition_version_state: rustfs_filemeta::TransitionVersionState::Unknown,
+            user_defined: user_defined.into(),
+            ..Default::default()
+        };
+
+        let err = super::free_version_remote_tuple_matches(&make_info(legacy_metadata), &make_info(explicit_metadata))
+            .expect_err("mixed legacy-missing and explicit unknown provenance must fail closed");
+
+        assert_eq!(err.kind(), std::io::ErrorKind::WouldBlock);
+    }
+
+    #[cfg(feature = "test-util")]
+    #[tokio::test]
+    async fn free_version_delete_probes_legacy_unknown_exact_version_before_remove() {
+        let manager = TierConfigMgr::new();
+        let tier = "WARM";
+        let backend = register_mock_tier(&manager, tier).await;
+        let identity = test_tier_destination_identity(&manager, tier).await;
+        let remote_object = format!("remote/{}", Uuid::new_v4());
+        let body = Bytes::from_static(b"legacy exact cleanup body");
+        let remote_version = backend
+            .put(
+                &remote_object,
+                ReaderImpl::Body(body),
+                i64::try_from(b"legacy exact cleanup body".len()).expect("body length should fit"),
+            )
+            .await
+            .expect("mock remote object should be stored");
+        let mut user_defined = user_defined_with_tier_destination_identity(identity);
+        insert_legacy_transition_version_id(&mut user_defined, &remote_version);
+        backend.clear_op_log().await;
+        let object_info = ObjectInfo {
+            transitioned_object: TransitionedObject {
+                name: remote_object.clone(),
+                version_id: remote_version,
+                tier: tier.to_string(),
+                ..Default::default()
+            },
+            transition_version_state: rustfs_filemeta::TransitionVersionState::Unknown,
+            user_defined: user_defined.into(),
+            ..Default::default()
+        };
+
+        super::delete_free_version_remote_object(&object_info, &manager)
+            .await
+            .expect("probe-proven legacy exact cleanup should delete the remote version");
+        super::delete_free_version_remote_object(&object_info, &manager)
+            .await
+            .expect("a retry after the exact remote version is already missing should be idempotent");
+
+        assert_eq!(
+            backend.op_log().await,
+            vec![
+                MockWarmOp::Probe {
+                    object: remote_object.clone()
+                },
+                MockWarmOp::Remove {
+                    object: remote_object.clone()
+                },
+                MockWarmOp::Probe {
+                    object: remote_object.clone()
+                },
+            ]
+        );
+        assert_eq!(
+            backend.remove_versions().await,
+            vec![(remote_object, object_info.transitioned_object.version_id)]
+        );
+    }
+
+    #[cfg(feature = "test-util")]
+    #[tokio::test]
+    async fn free_version_delete_probes_legacy_unknown_unversioned_before_remove() {
+        let manager = TierConfigMgr::new();
+        let tier = "WARM";
+        let backend = register_mock_tier(&manager, tier).await;
+        backend.set_put_remote_version(Some(String::new())).await;
+        let identity = test_tier_destination_identity(&manager, tier).await;
+        let remote_object = format!("remote/{}", Uuid::new_v4());
+        let body = Bytes::from_static(b"legacy unversioned cleanup body");
+        let remote_version = backend
+            .put(
+                &remote_object,
+                ReaderImpl::Body(body),
+                i64::try_from(b"legacy unversioned cleanup body".len()).expect("body length should fit"),
+            )
+            .await
+            .expect("mock remote object should be stored");
+        assert!(remote_version.is_empty());
+        backend.clear_op_log().await;
+        let mut user_defined = user_defined_with_tier_destination_identity(identity);
+        user_defined.insert("x-minio-internal-transitioned-versionID".to_string(), String::new());
+        let object_info = ObjectInfo {
+            transitioned_object: TransitionedObject {
+                name: remote_object.clone(),
+                version_id: String::new(),
+                tier: tier.to_string(),
+                ..Default::default()
+            },
+            transition_version_state: rustfs_filemeta::TransitionVersionState::Unknown,
+            user_defined: user_defined.into(),
+            ..Default::default()
+        };
+
+        super::delete_free_version_remote_object(&object_info, &manager)
+            .await
+            .expect("probe-proven legacy unversioned cleanup should delete the remote object");
+
+        assert_eq!(
+            backend.op_log().await,
+            vec![
+                MockWarmOp::Probe {
+                    object: remote_object.clone()
+                },
+                MockWarmOp::Remove {
+                    object: remote_object.clone()
+                },
+                MockWarmOp::Probe {
+                    object: remote_object.clone()
+                },
+            ]
+        );
+        assert_eq!(backend.remove_versions().await, vec![(remote_object, String::new())]);
+    }
+
+    #[cfg(feature = "test-util")]
+    #[tokio::test]
+    async fn free_version_delete_retains_legacy_unknown_when_probe_disagrees() {
+        let manager = TierConfigMgr::new();
+        let tier = "WARM";
+        let backend = register_mock_tier(&manager, tier).await;
+        let identity = test_tier_destination_identity(&manager, tier).await;
+        let remote_object = format!("remote/{}", Uuid::new_v4());
+        backend
+            .set_transition_candidate_probe_override(Some(TransitionCandidateProbe::VersionedPresent(
+                "different-version".to_string(),
+            )))
+            .await;
+        let mut user_defined = user_defined_with_tier_destination_identity(identity);
+        insert_legacy_transition_version_id(&mut user_defined, "legacy-version");
+        let object_info = ObjectInfo {
+            transitioned_object: TransitionedObject {
+                name: remote_object.clone(),
+                version_id: "legacy-version".to_string(),
+                tier: tier.to_string(),
+                ..Default::default()
+            },
+            transition_version_state: rustfs_filemeta::TransitionVersionState::Unknown,
+            user_defined: user_defined.into(),
+            ..Default::default()
+        };
+
+        let err = super::delete_free_version_remote_object(&object_info, &manager)
+            .await
+            .expect_err("legacy unknown cleanup must not delete when the probe disagrees");
+
+        assert_eq!(err.kind(), std::io::ErrorKind::WouldBlock);
+        assert_eq!(backend.op_log().await, vec![MockWarmOp::Probe { object: remote_object }]);
         assert_eq!(backend.remove_count().await, 0);
     }
 

crates/ecstore/src/bucket/lifecycle/mod.rs

@@ -18,6 +18,7 @@ mod config_boundary;
 pub mod core;
 mod durable_namespace;
 pub mod evaluator;
+pub mod legacy_transition_state_reconcile;
 pub mod manual_transition_job;
 mod metadata_boundary;
 pub(crate) use metadata_boundary::{LifecycleExpiryConfigs, get_expiry_configs, get_lifecycle_config};

crates/ecstore/src/bucket/lifecycle/transition_transaction.rs

@@ -830,6 +830,7 @@ impl From<TransitionCandidateProbe> for TransitionOperatorProbe {
         match value {
             TransitionCandidateProbe::Missing => Self::Missing,
             TransitionCandidateProbe::UnversionedPresent => Self::UnversionedPresent,
+            TransitionCandidateProbe::SuspendedNullPresent => Self::VersionedPresent("null".to_string()),
             TransitionCandidateProbe::VersionedPresent(version_id) => Self::VersionedPresent(version_id),
             TransitionCandidateProbe::Ambiguous => Self::Ambiguous,
             TransitionCandidateProbe::Unsupported => Self::Unsupported,
@@ -1183,6 +1184,10 @@ async fn recover_unknown_upload_outcome(
         TransitionCandidateProbe::UnversionedPresent => {
             cleanup_recovered_unknown_upload_candidate(api, transaction, TransitionRemoteVersion::unversioned()).await
         }
+        TransitionCandidateProbe::SuspendedNullPresent => {
+            cleanup_recovered_unknown_upload_candidate(api, transaction, TransitionRemoteVersion::versioned("null".to_string()))
+                .await
+        }
         TransitionCandidateProbe::VersionedPresent(version_id)
             if Uuid::parse_str(&version_id).is_ok_and(|version_id| version_id.is_nil()) =>
         {
@@ -1512,6 +1517,14 @@ mod tests {
 
     const BACKEND_FINGERPRINT: [u8; 32] = [7; 32];
 
+    #[test]
+    fn suspended_null_probe_preserves_operator_null_version_semantics() {
+        assert_eq!(
+            TransitionOperatorProbe::from(TransitionCandidateProbe::SuspendedNullPresent),
+            TransitionOperatorProbe::VersionedPresent("null".to_string())
+        );
+    }
+
     #[derive(Default)]
     struct MemoryTransactionStore {
         records: HashMap<Uuid, Vec<u8>>,

crates/ecstore/src/services/tier/test_util.rs

@@ -701,7 +701,7 @@ impl WarmBackend for MockWarmBackend {
         Ok(version)
     }
 
-    async fn get(&self, object: &str, _rv: &str, opts: WarmBackendGetOpts) -> Result<ReadCloser, std::io::Error> {
+    async fn get(&self, object: &str, rv: &str, opts: WarmBackendGetOpts) -> Result<ReadCloser, std::io::Error> {
         self.precondition().await?;
         let barrier = self.inner.get_barrier.lock().await.take();
         if let Some(barrier) = barrier {
@@ -719,6 +719,9 @@ impl WarmBackend for MockWarmBackend {
         let Some(stored) = objects.get(object) else {
             return Err(std::io::Error::new(std::io::ErrorKind::NotFound, "mock object not found"));
         };
+        if !rv.is_empty() && stored.remote_version_id != rv {
+            return Err(std::io::Error::new(std::io::ErrorKind::NotFound, "NoSuchVersion"));
+        }
         let bytes = &stored.bytes;
 
         let start = opts.start_offset.max(0) as usize;
@@ -789,6 +792,8 @@ impl WarmBackend for MockWarmBackend {
         };
         if stored.remote_version_id.is_empty() {
             Ok(TransitionCandidateProbe::UnversionedPresent)
+        } else if stored.remote_version_id == "null" {
+            Ok(TransitionCandidateProbe::SuspendedNullPresent)
         } else {
             Ok(TransitionCandidateProbe::VersionedPresent(stored.remote_version_id.clone()))
         }
@@ -988,7 +993,7 @@ mod tests {
     use bytes::Bytes;
 
     #[tokio::test]
-    async fn mock_probe_distinguishes_missing_unversioned_and_versioned_candidates() {
+    async fn mock_probe_distinguishes_all_known_remote_version_states() {
         let backend = MockWarmBackend::new();
 
         assert_eq!(
@@ -1026,6 +1031,19 @@ mod tests {
             TransitionCandidateProbe::VersionedPresent(remote_version)
         );
 
+        backend.set_put_remote_version(Some("null".to_string())).await;
+        backend
+            .put("suspended-null", ReaderImpl::Body(Bytes::new()), 0)
+            .await
+            .expect("put suspended null candidate");
+        assert_eq!(
+            backend
+                .probe_transition_candidate_state("suspended-null")
+                .await
+                .expect("probe suspended null candidate"),
+            TransitionCandidateProbe::SuspendedNullPresent
+        );
+
         assert_eq!(
             backend
                 .op_log()
@@ -1033,7 +1051,7 @@ mod tests {
                 .into_iter()
                 .filter(|op| matches!(op, MockWarmOp::Probe { .. }))
                 .count(),
-            3
+            4
         );
     }
 

crates/ecstore/src/services/tier/warm_backend.rs

@@ -78,6 +78,8 @@ pub struct WarmBackendGetOpts {
 pub enum TransitionCandidateProbe {
     Missing,
     UnversionedPresent,
+    /// The provider listed the candidate under the exact S3 `null` version.
+    SuspendedNullPresent,
     VersionedPresent(String),
     Ambiguous,
     Unsupported,

crates/ecstore/src/services/tier/warm_backend_s3.rs

@@ -214,7 +214,8 @@ impl WarmBackendS3 {
                 return Ok(TransitionCandidateProbe::Ambiguous);
             }
             if !versions.is_truncated {
-                return classify_transition_candidates(candidates, bucket_versioning);
+                let confirmed_versioning = self.remote_bucket_versioning().await?;
+                return classify_transition_candidates(candidates, bucket_versioning, confirmed_versioning);
             }
 
             advance_version_markers(&mut key_marker, &mut version_id_marker, &versions)?;
@@ -275,7 +276,8 @@ impl WarmBackendS3 {
                     version_id: matched_version,
                     ambiguous: false,
                 };
-                return classify_transition_candidates(candidates, bucket_versioning);
+                let confirmed_versioning = self.remote_bucket_versioning().await?;
+                return classify_transition_candidates(candidates, bucket_versioning, confirmed_versioning);
             }
             advance_version_markers(&mut key_marker, &mut version_id_marker, &versions)?;
         }
@@ -310,9 +312,15 @@ fn transition_candidate_metadata_matches(
 
 fn classify_transition_candidates(
     candidates: TransitionCandidateVersions,
-    bucket_versioning: RemoteBucketVersioning,
+    initial_versioning: RemoteBucketVersioning,
+    confirmed_versioning: RemoteBucketVersioning,
 ) -> Result<TransitionCandidateProbe, std::io::Error> {
-    let probe = candidates.classify(bucket_versioning);
+    // GetBucketVersioning and ListObjectVersions are separate requests. An
+    // observed state change makes the combined proof unsafe to persist.
+    if initial_versioning != confirmed_versioning {
+        return Ok(TransitionCandidateProbe::Ambiguous);
+    }
+    let probe = candidates.classify(initial_versioning);
     if let TransitionCandidateProbe::VersionedPresent(version_id) = &probe {
         validate_remote_version_id(version_id)?;
     }
@@ -366,8 +374,19 @@ impl TransitionCandidateVersions {
         };
 
         match bucket_versioning {
-            RemoteBucketVersioning::Disabled => TransitionCandidateProbe::UnversionedPresent,
-            RemoteBucketVersioning::Suspended if version_id == "null" => TransitionCandidateProbe::VersionedPresent(version_id),
+            // A never-versioned S3 object may be listed with either an empty
+            // version or the provider's `null` sentinel. Any opaque version is
+            // inconsistent with a disabled bucket and must remain ambiguous.
+            RemoteBucketVersioning::Disabled if version_id.is_empty() || version_id == "null" => {
+                TransitionCandidateProbe::UnversionedPresent
+            }
+            RemoteBucketVersioning::Disabled => TransitionCandidateProbe::Ambiguous,
+            // A `null` version survives a later transition back to Enabled, so
+            // the listed identifier, not only the current bucket status, binds
+            // suspended-null request routing.
+            RemoteBucketVersioning::Suspended | RemoteBucketVersioning::Enabled if version_id == "null" => {
+                TransitionCandidateProbe::SuspendedNullPresent
+            }
             RemoteBucketVersioning::Suspended | RemoteBucketVersioning::Enabled if !version_id.is_empty() => {
                 TransitionCandidateProbe::VersionedPresent(version_id)
             }
@@ -426,7 +445,8 @@ mod tests {
         for page in pages {
             candidates.extend("archive/object", page);
         }
-        candidates.classify(bucket_versioning)
+        classify_transition_candidates(candidates, bucket_versioning, bucket_versioning)
+            .expect("fixture version identifiers are valid")
     }
 
     fn candidate_identity() -> TransitionCandidateIdentity {
@@ -505,7 +525,35 @@ mod tests {
                 RemoteBucketVersioning::Suspended,
                 &[list_versions(&[("archive/object", "null")], &[], false)],
             ),
-            TransitionCandidateProbe::VersionedPresent("null".to_string())
+            TransitionCandidateProbe::SuspendedNullPresent
+        );
+        assert_eq!(
+            classify_pages(
+                RemoteBucketVersioning::Enabled,
+                &[list_versions(&[("archive/object", "null")], &[], false)],
+            ),
+            TransitionCandidateProbe::SuspendedNullPresent
+        );
+        assert_eq!(
+            classify_pages(
+                RemoteBucketVersioning::Suspended,
+                &[list_versions(&[("archive/object", "version-a")], &[], false)],
+            ),
+            TransitionCandidateProbe::VersionedPresent("version-a".to_string())
+        );
+        assert_eq!(
+            classify_pages(
+                RemoteBucketVersioning::Disabled,
+                &[list_versions(&[("archive/object", "null")], &[], false)],
+            ),
+            TransitionCandidateProbe::UnversionedPresent
+        );
+        assert_eq!(
+            classify_pages(
+                RemoteBucketVersioning::Disabled,
+                &[list_versions(&[("archive/object", "unexpected-version")], &[], false)],
+            ),
+            TransitionCandidateProbe::Ambiguous
         );
         assert_eq!(
             classify_pages(RemoteBucketVersioning::Enabled, &[list_versions(&[("archive/object", "")], &[], false)],),
@@ -573,11 +621,23 @@ mod tests {
         let mut candidates = TransitionCandidateVersions::default();
         candidates.extend("archive/object", &list_versions(&[("archive/object", "version\ninjection")], &[], false));
 
-        let err = classify_transition_candidates(candidates, RemoteBucketVersioning::Enabled)
+        let err = classify_transition_candidates(candidates, RemoteBucketVersioning::Enabled, RemoteBucketVersioning::Enabled)
             .expect_err("control characters in listed version IDs must fail closed");
         assert_eq!(err.kind(), std::io::ErrorKind::InvalidData);
     }
 
+    #[test]
+    fn transition_candidate_probe_rejects_bucket_versioning_drift() {
+        let mut candidates = TransitionCandidateVersions::default();
+        candidates.extend("archive/object", &list_versions(&[("archive/object", "null")], &[], false));
+
+        assert_eq!(
+            classify_transition_candidates(candidates, RemoteBucketVersioning::Suspended, RemoteBucketVersioning::Enabled,)
+                .expect("observed versioning drift should be a safe probe result"),
+            TransitionCandidateProbe::Ambiguous
+        );
+    }
+
     #[test]
     fn remote_bucket_versioning_status_parser_fails_closed() {
         assert_eq!(

crates/ecstore/src/set_disk/mod.rs

@@ -3877,6 +3877,31 @@ pub struct SetDisks {
     >,
 }
 
+/// Read every available `xl.meta` copy for an exact logical object after
+/// enforcing this set's metadata read quorum. Callers use the individual
+/// buffers only for diagnostics and immutable reconciliation digests; a
+/// missing disk remains visible as `None` and must never be mistaken for an
+/// absent metadata key.
+pub(crate) async fn read_legacy_transition_state_metadata_copies(
+    set: &SetDisks,
+    bucket: &str,
+    object: &str,
+) -> Result<Vec<Option<Vec<u8>>>> {
+    let disk_object = rustfs_utils::path::encode_dir_object(object);
+    let disks = set.get_disks_internal().await;
+    if disks.is_empty() {
+        return Err(to_object_err(StorageError::ErasureReadQuorum, vec![bucket, object]));
+    }
+
+    let read_quorum = disks.len().div_ceil(2).max(1);
+    let (copies, errs) = SetDisks::read_all_raw_file_info(&disks, bucket, disk_object.as_str(), false).await;
+    if let Some(err) = reduce_read_quorum_errs(&errs, OBJECT_OP_IGNORED_ERRS, read_quorum) {
+        return Err(to_object_err(err.into(), vec![bucket, object]));
+    }
+
+    Ok(copies.into_iter().map(|copy| copy.map(|copy| copy.buf)).collect())
+}
+
 // DistributedLock sends the raw ObjectKey to its clients; LockRegistry clones
 // each endpoint's canonical Arc, so an exact Arc set identifies the lock domain.
 pub(crate) fn same_distributed_lock_domain(left: &[Arc<dyn LockClient>], right: &[Arc<dyn LockClient>]) -> bool {

crates/ecstore/src/store/init.rs

@@ -11562,6 +11562,7 @@ mod tests {
         pool_index: usize,
         bucket: &str,
         object: &str,
+        minio_unversioned: bool,
     ) {
         for disk_index in 0..4 {
             let metadata_path =
@@ -11595,6 +11596,11 @@ mod tests {
                 ] {
                     rustfs_utils::http::metadata_compat::remove_bytes(&mut object_meta.meta_sys, suffix);
                 }
+                if minio_unversioned {
+                    object_meta
+                        .meta_sys
+                        .insert("x-minio-internal-transitioned-versionID".to_string(), Vec::new());
+                }
                 *shallow = rustfs_filemeta::FileMetaShallowVersion::try_from(version)
                     .expect("legacy transitioned version should re-encode");
             }
@@ -11605,6 +11611,152 @@ mod tests {
         }
     }
 
+    #[cfg(feature = "test-util")]
+    async fn read_store_body(
+        store: &Arc<crate::store::ECStore>,
+        bucket: &str,
+        object: &str,
+        range: Option<HTTPRangeSpec>,
+        opts: &ObjectOptions,
+    ) -> Vec<u8> {
+        let mut reader = store
+            .get_object_reader(bucket, object, range, HeaderMap::new(), opts)
+            .await
+            .expect("object reader should open");
+        let mut body = Vec::new();
+        reader.stream.read_to_end(&mut body).await.expect("object body should drain");
+        body
+    }
+
+    #[cfg(feature = "test-util")]
+    #[tokio::test]
+    #[serial_test::serial(storage_class_env)]
+    async fn legacy_unknown_unversioned_transition_supports_head_get_and_range_without_backfill() {
+        let temp_dir = tempfile::tempdir().expect("create legacy unknown unversioned store dir");
+        let (ctx, store, _shutdown) =
+            without_storage_class_env(build_isolated_test_store(temp_dir.path(), "legacy-unknown-unversioned-read", &[4])).await;
+        crate::bucket::metadata_sys::init_bucket_metadata_sys(store.clone(), Vec::new()).await;
+        let tier_name = "LEGACY-UNKNOWN-UNVERSIONED-READ";
+        let backend = register_mock_tier(&ctx.tier_config_mgr(), tier_name).await;
+        backend.set_put_remote_version(Some(String::new())).await;
+        let bucket = "legacy-unknown-unversioned-read-bucket";
+        let object = "object.bin";
+        let payload = b"legacy unversioned remote tier object remains readable".repeat(1024);
+        store
+            .make_bucket(bucket, &MakeBucketOptions::default())
+            .await
+            .expect("legacy source bucket should be created");
+        let mut reader = PutObjReader::from_vec(payload.clone());
+        let source = store
+            .put_object(bucket, object, &mut reader, &ObjectOptions::default())
+            .await
+            .expect("legacy source should be written");
+        store
+            .transition_object(
+                bucket,
+                object,
+                &ObjectOptions {
+                    transition: TransitionOptions {
+                        status: TRANSITION_PENDING.to_string(),
+                        tier: tier_name.to_string(),
+                        etag: source.etag.clone().expect("legacy source should have an etag"),
+                        ..Default::default()
+                    },
+                    mod_time: source.mod_time,
+                    ..Default::default()
+                },
+            )
+            .await
+            .expect("legacy source should transition");
+        rewrite_transitioned_xlmeta_as_legacy_unknown(temp_dir.path(), 0, bucket, object, true).await;
+        backend.clear_op_log().await;
+
+        let opts = ObjectOptions {
+            metadata_cache_safe: false,
+            ..Default::default()
+        };
+        let head = store
+            .get_object_info(bucket, object, &opts)
+            .await
+            .expect("legacy transitioned HEAD should use local metadata");
+        assert_eq!(head.transition_version_state, rustfs_filemeta::TransitionVersionState::Unknown);
+        assert!(head.transitioned_object.version_id.is_empty());
+        assert_eq!(
+            head.user_defined
+                .get("x-minio-internal-transitioned-versionID")
+                .map(String::as_str),
+            Some(""),
+            "the MinIO empty version-key provenance must survive xl.meta decoding"
+        );
+        assert!(
+            !rustfs_utils::http::metadata_compat::contains_key_str(
+                &head.user_defined,
+                rustfs_utils::http::metadata_compat::SUFFIX_TRANSITIONED_VERSION_STATE,
+            ),
+            "the compatibility read must not synthesize version-state metadata"
+        );
+
+        let full_body = read_store_body(&store, bucket, object, None, &opts).await;
+        assert_eq!(full_body, payload);
+
+        let range = HTTPRangeSpec {
+            is_suffix_length: false,
+            start: 7,
+            end: 38,
+        };
+        let ranged_body = read_store_body(&store, bucket, object, Some(range), &opts).await;
+        assert_eq!(ranged_body, &payload[7..=38]);
+
+        let after_read = store.pools[0]
+            .get_disks_by_key(object)
+            .load_file_info_versions_exact(bucket, object)
+            .await
+            .expect("legacy metadata should remain readable after GET")
+            .expect("legacy object metadata should remain on disk")
+            .versions
+            .into_iter()
+            .find(|version| version.transition_status == rustfs_filemeta::TRANSITION_COMPLETE)
+            .expect("legacy transitioned source should remain visible after GET");
+        assert_eq!(after_read.transition_version_state, rustfs_filemeta::TransitionVersionState::Unknown);
+        assert!(after_read.transition_version.is_none());
+        assert!(after_read.transition_version_id.is_none());
+        assert_eq!(
+            after_read
+                .metadata
+                .get("x-minio-internal-transitioned-versionID")
+                .map(String::as_str),
+            Some(""),
+            "the MinIO empty version-key provenance must remain after GET and Range GET"
+        );
+        assert!(
+            !rustfs_utils::http::metadata_compat::contains_key_str(
+                &after_read.metadata,
+                rustfs_utils::http::metadata_compat::SUFFIX_TRANSITIONED_VERSION_STATE,
+            ),
+            "the compatibility read must remain side-effect free"
+        );
+
+        assert_eq!(
+            backend.op_log().await,
+            vec![
+                MockWarmOp::Probe {
+                    object: after_read.transitioned_objname.clone(),
+                },
+                MockWarmOp::Get {
+                    object: after_read.transitioned_objname.clone(),
+                },
+                MockWarmOp::Probe {
+                    object: after_read.transitioned_objname.clone(),
+                },
+                MockWarmOp::Get {
+                    object: after_read.transitioned_objname,
+                },
+            ],
+            "legacy reads should probe before each unversioned GET and never mutate local metadata"
+        );
+        assert_eq!(backend.remove_count().await, 0);
+    }
+
     #[cfg(feature = "test-util")]
     #[tokio::test]
     #[serial_test::serial(storage_class_env)]
@@ -11645,7 +11797,7 @@ mod tests {
                 )
                 .await
                 .expect("legacy source should transition");
-            rewrite_transitioned_xlmeta_as_legacy_unknown(temp_dir.path(), 0, bucket, object).await;
+            rewrite_transitioned_xlmeta_as_legacy_unknown(temp_dir.path(), 0, bucket, object, false).await;
             let legacy = store.pools[0]
                 .get_disks_by_key(object)
                 .load_file_info_versions_exact(bucket, object)
@@ -12786,7 +12938,7 @@ mod tests {
                 .expect("merge-loser source should transition");
             copy_test_xlmeta_between_pools(temp_dir.path(), 0, 1, bucket, object).await;
         }
-        rewrite_transitioned_xlmeta_as_legacy_unknown(temp_dir.path(), 1, bucket, "legacy/item.bin").await;
+        rewrite_transitioned_xlmeta_as_legacy_unknown(temp_dir.path(), 1, bucket, "legacy/item.bin", false).await;
         backend.set_remove_failure(true);
         store.pools[1]
             .delete_object(bucket, "hidden/item.bin", ObjectOptions::default())

crates/filemeta/src/filemeta/version.rs

@@ -297,6 +297,20 @@ fn transitioned_version_from_bytes(value: Option<&[u8]>, state: TransitionVersio
     }
 }
 
+fn transition_version_metadata_value(raw: &[u8], decoded: Option<&str>) -> String {
+    decoded.map(str::to_owned).unwrap_or_else(|| {
+        if raw.is_empty() {
+            String::new()
+        } else {
+            String::from_utf8_lossy(raw).into_owned()
+        }
+    })
+}
+
+fn is_transition_version_metadata_key(key: &str) -> bool {
+    strip_internal_prefix_preserving_case(key).is_some_and(|suffix| suffix.eq_ignore_ascii_case(SUFFIX_TRANSITIONED_VERSION_ID))
+}
+
 fn validate_transition_version_state(state: TransitionVersionState, version: Option<&str>) -> Result<()> {
     let valid = match state {
         TransitionVersionState::Unknown | TransitionVersionState::KnownDisabled => version.is_none(),
@@ -366,14 +380,26 @@ impl<'a> DerivedInternalMetadata<'a> {
             }
             *slot = Some(value.as_slice());
         }
+        fn merge_consistent<'a>(canonical: Option<&'a [u8]>, legacy: Option<&'a [u8]>) -> Result<Option<&'a [u8]>> {
+            if let (Some(canonical), Some(legacy)) = (canonical, legacy)
+                && canonical != legacy
+            {
+                return Err(Error::FileCorrupt);
+            }
+            Ok(canonical.or(legacy))
+        }
+
         Ok(Self {
             checksum: canonical.checksum.or(legacy.checksum),
             part_checksums: canonical.part_checksums.or(legacy.part_checksums),
-            transition_status: canonical.transition_status.or(legacy.transition_status),
-            transitioned_object: canonical.transitioned_object.or(legacy.transitioned_object),
-            transitioned_version: canonical.transitioned_version.or(legacy.transitioned_version),
-            transitioned_version_state: canonical.transitioned_version_state.or(legacy.transitioned_version_state),
-            transition_tier: canonical.transition_tier.or(legacy.transition_tier),
+            transition_status: merge_consistent(canonical.transition_status, legacy.transition_status)?,
+            transitioned_object: merge_consistent(canonical.transitioned_object, legacy.transitioned_object)?,
+            transitioned_version: merge_consistent(canonical.transitioned_version, legacy.transitioned_version)?,
+            transitioned_version_state: merge_consistent(
+                canonical.transitioned_version_state,
+                legacy.transitioned_version_state,
+            )?,
+            transition_tier: merge_consistent(canonical.transition_tier, legacy.transition_tier)?,
         })
     }
 }
@@ -438,8 +464,14 @@ impl FileInfo {
     }
 }
 
-fn set_transition_version_state(meta_sys: &mut HashMap<String, Vec<u8>>, state: TransitionVersionState) {
-    if state == TransitionVersionState::Unknown {
+fn set_transition_version_state(
+    meta_sys: &mut HashMap<String, Vec<u8>>,
+    state: TransitionVersionState,
+    source_metadata: &HashMap<String, String>,
+) {
+    if state == TransitionVersionState::Unknown
+        && !rustfs_utils::http::metadata_compat::contains_key_str(source_metadata, SUFFIX_TRANSITIONED_VERSION_STATE)
+    {
         remove_bytes(meta_sys, SUFFIX_TRANSITIONED_VERSION_STATE);
     } else {
         insert_bytes(meta_sys, SUFFIX_TRANSITIONED_VERSION_STATE, state.as_str().as_bytes().to_vec());
@@ -2643,6 +2675,11 @@ impl MetaObject {
         if derived_metadata.transitioned_version_state.is_some() {
             validate_transition_version_state(transition_version_state, transition_version.as_deref())?;
         }
+        for (key, value) in &self.meta_sys {
+            if is_transition_version_metadata_key(key) {
+                metadata.insert(key.to_owned(), transition_version_metadata_value(value, transition_version.as_deref()));
+            }
+        }
         let transition_version_id = transition_version.as_deref().and_then(|value| Uuid::parse_str(value).ok());
         let transition_tier = derived_metadata
             .transition_tier
@@ -2689,7 +2726,7 @@ impl MetaObject {
         } else {
             remove_bytes(&mut self.meta_sys, SUFFIX_TRANSITIONED_VERSION_ID);
         }
-        set_transition_version_state(&mut self.meta_sys, fi.transition_version_state);
+        set_transition_version_state(&mut self.meta_sys, fi.transition_version_state, &fi.metadata);
         insert_bytes(&mut self.meta_sys, SUFFIX_TRANSITION_TIER, fi.transition_tier.as_bytes().to_vec());
         if let Some(destination_id) = get_str(&fi.metadata, SUFFIX_TRANSITION_TIER_DESTINATION_ID) {
             insert_bytes(&mut self.meta_sys, SUFFIX_TRANSITION_TIER_DESTINATION_ID, destination_id.into_bytes());
@@ -2830,7 +2867,7 @@ impl From<FileInfo> for MetaObject {
             insert_bytes(&mut meta_sys, SUFFIX_TRANSITIONED_VERSION_ID, transition_version);
         }
         if !value.transition_status.is_empty() {
-            set_transition_version_state(&mut meta_sys, value.transition_version_state);
+            set_transition_version_state(&mut meta_sys, value.transition_version_state, &value.metadata);
         }
 
         if !value.transition_tier.is_empty() {
@@ -2985,6 +3022,12 @@ impl MetaDeleteMarker {
             fi.transition_version_state = transition_version_state_from_bytes(derived_metadata.transitioned_version_state)?;
             fi.transition_version =
                 transitioned_version_from_bytes(derived_metadata.transitioned_version, fi.transition_version_state);
+            for (key, value) in &self.meta_sys {
+                if is_transition_version_metadata_key(key) {
+                    fi.metadata
+                        .insert(key.to_owned(), transition_version_metadata_value(value, fi.transition_version.as_deref()));
+                }
+            }
             fi.transition_version_id = fi.transition_version.as_deref().and_then(|value| Uuid::parse_str(value).ok());
             if derived_metadata.transitioned_version_state.is_some() {
                 validate_transition_version_state(fi.transition_version_state, fi.transition_version.as_deref())?;
@@ -3152,7 +3195,7 @@ impl From<FileInfo> for MetaDeleteMarker {
             insert_bytes(&mut meta_sys, SUFFIX_TRANSITIONED_VERSION_ID, transition_version);
         }
         if !value.transition_status.is_empty() || value.tier_free_version() {
-            set_transition_version_state(&mut meta_sys, value.transition_version_state);
+            set_transition_version_state(&mut meta_sys, value.transition_version_state, &value.metadata);
         }
         if !value.transition_tier.is_empty() {
             insert_bytes(&mut meta_sys, SUFFIX_TRANSITION_TIER, value.transition_tier.as_bytes().to_vec());
@@ -4574,6 +4617,7 @@ mod tests {
             .into_fileinfo("b", "k", false)
             .expect("into_fileinfo");
         assert_eq!(fi.transition_version_id, None);
+        assert_eq!(get_str(&fi.metadata, SUFFIX_TRANSITIONED_VERSION_ID), Some(String::new()));
     }
 
     #[test]
@@ -4585,6 +4629,10 @@ mod tests {
             .into_fileinfo("b", "k", false)
             .expect("into_fileinfo");
         assert_eq!(fi.transition_version_id, None);
+        assert!(
+            get_str(&fi.metadata, SUFFIX_TRANSITIONED_VERSION_ID).is_some_and(|value| !value.is_empty()),
+            "nil UUID bytes must remain distinguishable from an empty MinIO version"
+        );
     }
 
     #[test]
@@ -4598,6 +4646,7 @@ mod tests {
         assert_eq!(fi.transition_version_id, Some(id));
         assert_eq!(fi.transition_version, Some(id.to_string()));
         assert_eq!(fi.transition_version_state, TransitionVersionState::Unknown);
+        assert_eq!(get_str(&fi.metadata, SUFFIX_TRANSITIONED_VERSION_ID), Some(id.to_string()));
     }
 
     #[test]
@@ -4637,6 +4686,36 @@ mod tests {
         assert_eq!(fi.transition_version_state, TransitionVersionState::Unknown);
     }
 
+    #[test]
+    fn meta_object_transition_version_state_explicit_unknown_is_not_legacy_missing() {
+        let mut metadata = HashMap::new();
+        rustfs_utils::http::metadata_compat::insert_str(
+            &mut metadata,
+            SUFFIX_TRANSITIONED_VERSION_STATE,
+            TransitionVersionState::Unknown.as_str().to_string(),
+        );
+        let fi = FileInfo {
+            transition_status: "complete".to_string(),
+            transition_version_state: TransitionVersionState::Unknown,
+            metadata,
+            ..Default::default()
+        };
+
+        let object = MetaObject::from(fi);
+        assert_eq!(
+            get_consistent_bytes(&object.meta_sys, SUFFIX_TRANSITIONED_VERSION_STATE),
+            Some(b"unknown".as_slice())
+        );
+        let decoded = object
+            .into_fileinfo("b", "k", false)
+            .expect("explicit unknown state should decode");
+        assert_eq!(decoded.transition_version_state, TransitionVersionState::Unknown);
+        assert_eq!(
+            rustfs_utils::http::metadata_compat::get_consistent_str(&decoded.metadata, SUFFIX_TRANSITIONED_VERSION_STATE,),
+            Some("unknown")
+        );
+    }
+
     #[test]
     fn meta_object_transition_version_state_exact_round_trips_dual_keys() {
         let id = sample_version_id();
@@ -4753,6 +4832,10 @@ mod tests {
             .expect("invalid transition version bytes must not fail the object read");
         assert_eq!(fi.transition_version_id, None);
         assert_eq!(fi.transition_version, None);
+        assert!(
+            get_str(&fi.metadata, SUFFIX_TRANSITIONED_VERSION_ID).is_some_and(|value| !value.is_empty()),
+            "invalid raw bytes must remain distinguishable from an empty MinIO version"
+        );
     }
 
     #[test]
@@ -4795,6 +4878,10 @@ mod tests {
         .into_fileinfo("b", "k", false)
         .expect("nil tier version should remain an absent remote version");
         assert_eq!(fi.transition_version_id, None);
+        assert!(
+            get_str(&fi.metadata, SUFFIX_TRANSITIONED_VERSION_ID).is_some_and(|value| !value.is_empty()),
+            "nil UUID bytes must remain distinguishable from an empty MinIO version"
+        );
     }
 
     #[test]
@@ -4812,6 +4899,7 @@ mod tests {
         .expect("legacy binary UUID tier version should decode");
         assert_eq!(fi.transition_version_id, Some(id));
         assert_eq!(fi.transition_version, Some(id.to_string()));
+        assert_eq!(get_str(&fi.metadata, SUFFIX_TRANSITIONED_VERSION_ID), Some(id.to_string()));
     }
 
     #[test]
@@ -4910,6 +4998,23 @@ mod tests {
         assert_eq!(err, Error::FileCorrupt);
     }
 
+    #[test]
+    fn meta_object_transition_version_state_mixed_case_alias_conflict_fails_closed() {
+        let sys = HashMap::from([
+            (
+                format!("{RUSTFS_INTERNAL_PREFIX}{SUFFIX_TRANSITIONED_VERSION_STATE}"),
+                b"unknown".to_vec(),
+            ),
+            ("X-Minio-Internal-transitioned-version-state".to_string(), b"exact".to_vec()),
+        ]);
+
+        let err = make_meta_object_with_sys(sys)
+            .into_fileinfo("b", "k", false)
+            .expect_err("mixed-case transition state aliases must agree");
+
+        assert_eq!(err, Error::FileCorrupt);
+    }
+
     #[test]
     fn version_header_sorts_before_prefers_object_over_delete_marker_on_equal_mod_time() {
         let object = FileMetaVersionHeader {

rustfs/src/admin/handlers/ilm_transition.rs

@@ -15,12 +15,13 @@
 use crate::admin::auth::authorize_admin_request;
 use crate::admin::router::{AdminOperation, Operation, S3Router};
 use crate::admin::runtime_sources::object_store_from_extensions;
-use crate::admin::storage_api::bucket::is_reserved_or_invalid_bucket;
+use crate::admin::storage_api::bucket::{is_reserved_or_invalid_bucket, utils::is_valid_object_prefix};
 use crate::admin::storage_api::error::StorageError;
 use crate::admin::storage_api::lifecycle::{
-    ManualTransitionCancelCheck, ManualTransitionJobRecord, ManualTransitionJobState, ManualTransitionProgressSink,
-    ManualTransitionQueueSnapshot, ManualTransitionRunOptions, ManualTransitionRunReport, ManualTransitionScopeAdmission,
-    ManualTransitionScopeAdmissionClaim, TransitionOperatorDeleteResult, TransitionOperatorError,
+    LegacyTransitionStateReconcileError, LegacyTransitionStateReconcileRequest, LegacyTransitionStateReconcileResponse,
+    LegacyTransitionStateReconcileSelector, ManualTransitionCancelCheck, ManualTransitionJobRecord, ManualTransitionJobState,
+    ManualTransitionProgressSink, ManualTransitionQueueSnapshot, ManualTransitionRunOptions, ManualTransitionRunReport,
+    ManualTransitionScopeAdmission, ManualTransitionScopeAdmissionClaim, TransitionOperatorDeleteResult, TransitionOperatorError,
     claim_manual_transition_scope_admission, delete_manual_transition_scope_admission_if_current,
     delete_transition_candidate_for_operator, enqueue_transition_for_existing_objects_scoped,
     finalize_missing_transition_transaction_for_operator, inspect_transition_transaction_for_operator,
@@ -230,6 +231,16 @@ pub fn register_ilm_transition_route(r: &mut S3Router<AdminOperation>) -> std::i
         format!("{ADMIN_PREFIX}/v3/ilm/transition/reconcile/{{transaction_id}}").as_str(),
         AdminOperation(&TransitionReconcileApplyHandler {}),
     )?;
+    r.insert(
+        Method::GET,
+        format!("{ADMIN_PREFIX}/v3/ilm/transition/state/reconcile").as_str(),
+        AdminOperation(&LegacyTransitionStateReconcileInspectHandler {}),
+    )?;
+    r.insert(
+        Method::POST,
+        format!("{ADMIN_PREFIX}/v3/ilm/transition/state/reconcile").as_str(),
+        AdminOperation(&LegacyTransitionStateReconcileApplyHandler {}),
+    )?;
     Ok(())
 }
 
@@ -423,6 +434,92 @@ fn transition_transaction_id_from_params(params: &Params<'_, '_>) -> S3Result<Uu
         .map_err(|_| s3_error!(InvalidArgument, "invalid transition transaction id"))
 }
 
+#[derive(Debug, Deserialize)]
+#[serde(deny_unknown_fields)]
+struct LegacyTransitionStateReconcileQuery {
+    bucket: Option<String>,
+    object: Option<String>,
+    #[serde(rename = "versionId")]
+    version_id: Option<String>,
+}
+
+fn parse_legacy_transition_state_reconcile_query(query: Option<&str>) -> S3Result<LegacyTransitionStateReconcileSelector> {
+    let query: LegacyTransitionStateReconcileQuery = serde_urlencoded::from_bytes(query.unwrap_or_default().as_bytes())
+        .map_err(|_| s3_error!(InvalidArgument, "invalid legacy transition-state reconcile query"))?;
+    let bucket = query
+        .bucket
+        .filter(|bucket| !bucket.is_empty())
+        .ok_or_else(|| s3_error!(InvalidRequest, "bucket is required"))?;
+    if is_reserved_or_invalid_bucket(&bucket, false) {
+        return Err(s3_error!(InvalidBucketName, "invalid bucket name"));
+    }
+
+    let object = query
+        .object
+        .filter(|object| !object.is_empty())
+        .ok_or_else(|| s3_error!(InvalidRequest, "object is required"))?;
+    if !is_valid_object_prefix(&object) || object.contains('\n') || object.contains('\r') {
+        return Err(s3_error!(InvalidArgument, "invalid object name"));
+    }
+
+    let version_id = query
+        .version_id
+        .filter(|version_id| !version_id.is_empty())
+        .ok_or_else(|| s3_error!(InvalidRequest, "versionId is required"))?;
+    let version_id = if version_id == "null" {
+        version_id
+    } else {
+        let parsed = Uuid::parse_str(&version_id).map_err(|_| s3_error!(InvalidArgument, "invalid local versionId"))?;
+        if parsed.is_nil() {
+            return Err(s3_error!(InvalidArgument, "invalid local versionId"));
+        }
+        parsed.to_string()
+    };
+
+    Ok(LegacyTransitionStateReconcileSelector {
+        bucket,
+        object,
+        version_id,
+    })
+}
+
+fn validate_legacy_transition_state_reconcile_request(
+    query_selector: &LegacyTransitionStateReconcileSelector,
+    confirm: bool,
+    request_selector: &LegacyTransitionStateReconcileSelector,
+) -> S3Result<()> {
+    if !confirm {
+        return Err(s3_error!(
+            InvalidRequest,
+            "legacy transition-state reconciliation requires confirm=true; use GET to inspect without changes"
+        ));
+    }
+    if request_selector != query_selector {
+        return Err(s3_error!(InvalidRequest, "request selector must exactly match the query selector"));
+    }
+    Ok(())
+}
+
+fn map_legacy_transition_state_reconcile_error(err: LegacyTransitionStateReconcileError) -> S3Error {
+    match err {
+        LegacyTransitionStateReconcileError::InvalidSelector(_) | LegacyTransitionStateReconcileError::InvalidRequest(_) => {
+            s3_error!(InvalidRequest, "invalid legacy transition-state reconciliation request")
+        }
+        LegacyTransitionStateReconcileError::StaleExpectedTuple(_) | LegacyTransitionStateReconcileError::Corrupt(_) => {
+            s3_error!(OperationAborted, "legacy transition-state reconciliation metadata is stale or corrupt")
+        }
+        LegacyTransitionStateReconcileError::WriteFenceUnavailable(_) => {
+            s3_error!(
+                OperationAborted,
+                "legacy transition-state reconciliation could not acquire safe write authority"
+            )
+        }
+        LegacyTransitionStateReconcileError::BackendUnavailable(_) => {
+            s3_error!(InternalError, "legacy transition-state reconciliation backend is unavailable")
+        }
+    }
+}
+
 fn map_transition_operator_error(err: TransitionOperatorError) -> S3Error {
     match err {
         TransitionOperatorError::NotFound => s3_error!(NoSuchKey, "transition transaction not found"),
@@ -1089,6 +1186,52 @@ impl Operation for TransitionReconcileApplyHandler {
     }
 }
 
+pub struct LegacyTransitionStateReconcileInspectHandler {}
+
+#[async_trait::async_trait]
+impl Operation for LegacyTransitionStateReconcileInspectHandler {
+    async fn call(&self, req: S3Request<Body>, _params: Params<'_, '_>) -> S3Result<S3Response<(StatusCode, Body)>> {
+        authorize_transition_admin_request(&req, AdminAction::ListTierAction).await?;
+        let selector = parse_legacy_transition_state_reconcile_query(req.uri.query())?;
+        let Some(store) = object_store_from_extensions(&req.extensions) else {
+            return Err(s3_error!(InternalError, "object store is not initialized"));
+        };
+        let response: LegacyTransitionStateReconcileResponse = store
+            .inspect_legacy_transition_state(selector)
+            .await
+            .map_err(map_legacy_transition_state_reconcile_error)?;
+        json_response(StatusCode::OK, &response)
+    }
+}
+
+pub struct LegacyTransitionStateReconcileApplyHandler {}
+
+#[async_trait::async_trait]
+impl Operation for LegacyTransitionStateReconcileApplyHandler {
+    async fn call(&self, req: S3Request<Body>, _params: Params<'_, '_>) -> S3Result<S3Response<(StatusCode, Body)>> {
+        authorize_transition_admin_request(&req, AdminAction::SetTierAction).await?;
+        let selector = parse_legacy_transition_state_reconcile_query(req.uri.query())?;
+        let store = object_store_from_extensions(&req.extensions);
+        let mut input = req.input;
+        let body = input
+            .store_all_limited(MAX_ADMIN_REQUEST_BODY_SIZE)
+            .await
+            .map_err(|_| s3_error!(InvalidRequest, "legacy transition-state reconciliation body is too large or unreadable"))?;
+        let request: LegacyTransitionStateReconcileRequest = serde_json::from_slice(&body)
+            .map_err(|_| s3_error!(InvalidRequest, "legacy transition-state reconciliation request must be valid JSON"))?;
+        validate_legacy_transition_state_reconcile_request(&selector, request.confirm, &request.selector)?;
+        let Some(store) = store else {
+            return Err(s3_error!(InternalError, "object store is not initialized"));
+        };
+
+        let response: LegacyTransitionStateReconcileResponse = store
+            .reconcile_legacy_transition_state(request)
+            .await
+            .map_err(map_legacy_transition_state_reconcile_error)?;
+        json_response(StatusCode::OK, &response)
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -1171,12 +1314,87 @@ mod tests {
         let apply = src
             .split("impl Operation for TransitionReconcileApplyHandler")
             .nth(1)
-            .and_then(|block| block.split("#[cfg(test)]").next())
+            .and_then(|block| block.split("pub struct LegacyTransitionStateReconcileInspectHandler").next())
             .expect("apply handler block");
         assert!(apply.contains("AdminAction::SetTierAction"));
         assert!(!apply.contains("AdminAction::ListTierAction"));
     }
 
+    #[test]
+    fn legacy_transition_state_query_requires_one_exact_selector() {
+        let version_id = Uuid::new_v4();
+        let query = format!("bucket=test-bucket&object=logs%2F2026%20report&versionId={version_id}");
+        let selector = parse_legacy_transition_state_reconcile_query(Some(&query)).expect("exact version selector should parse");
+        assert_eq!(selector.bucket, "test-bucket");
+        assert_eq!(selector.object, "logs/2026 report");
+        assert_eq!(selector.version_id, version_id.to_string());
+
+        let unversioned =
+            parse_legacy_transition_state_reconcile_query(Some("bucket=test-bucket&object=logs%2Fcurrent&versionId=null"))
+                .expect("explicit null selector should parse");
+        assert_eq!(unversioned.version_id, "null");
+
+        for query in [
+            None,
+            Some("bucket=test-bucket&object=key"),
+            Some("bucket=test-bucket&object=&versionId=null"),
+            Some("bucket=test-bucket&object=key&versionId="),
+            Some("bucket=test-bucket&object=key&versionId=not-a-uuid"),
+            Some("bucket=test-bucket&object=key&versionId=00000000-0000-0000-0000-000000000000"),
+            Some("bucket=test-bucket&object=bad%0Akey&versionId=null"),
+            Some("bucket=test-bucket&object=key&versionId=null&prefix=wide"),
+            Some("bucket=test-bucket&bucket=other-bucket&object=key&versionId=null"),
+        ] {
+            assert!(
+                parse_legacy_transition_state_reconcile_query(query).is_err(),
+                "query should fail closed: {query:?}"
+            );
+        }
+    }
+
+    #[test]
+    fn legacy_transition_state_apply_requires_confirmation_and_matching_selector() {
+        let selector = LegacyTransitionStateReconcileSelector {
+            bucket: "test-bucket".to_string(),
+            object: "key".to_string(),
+            version_id: "null".to_string(),
+        };
+        let different = LegacyTransitionStateReconcileSelector {
+            object: "other-key".to_string(),
+            ..selector.clone()
+        };
+
+        assert!(validate_legacy_transition_state_reconcile_request(&selector, false, &selector).is_err());
+        assert!(validate_legacy_transition_state_reconcile_request(&selector, true, &different).is_err());
+        validate_legacy_transition_state_reconcile_request(&selector, true, &selector)
+            .expect("confirmed exact selector should pass handler validation");
+    }
+
+    #[test]
+    fn legacy_transition_state_routes_use_read_and_write_tier_actions() {
+        let src = include_str!("ilm_transition.rs");
+        let inspect = src
+            .split("impl Operation for LegacyTransitionStateReconcileInspectHandler")
+            .nth(1)
+            .and_then(|block| {
+                block
+                    .split("impl Operation for LegacyTransitionStateReconcileApplyHandler")
+                    .next()
+            })
+            .expect("legacy inspect handler block");
+        assert!(inspect.contains("AdminAction::ListTierAction"));
+        assert!(!inspect.contains("AdminAction::SetTierAction"));
+
+        let apply = src
+            .split("impl Operation for LegacyTransitionStateReconcileApplyHandler")
+            .nth(1)
+            .and_then(|block| block.split("#[cfg(test)]").next())
+            .expect("legacy apply handler block");
+        assert!(apply.contains("AdminAction::SetTierAction"));
+        assert!(!apply.contains("AdminAction::ListTierAction"));
+        assert!(apply.contains("validate_legacy_transition_state_reconcile_request"));
+    }
+
     #[test]
     fn manual_transition_query_defaults_to_bounded_run() {
         let (bucket, options, run_mode) =
@@ -1632,6 +1850,24 @@ mod tests {
         assert_eq!(cancel_err.message(), Some("authentication required"));
     }
 
+    #[tokio::test]
+    async fn legacy_transition_state_handlers_reject_missing_credentials_before_selector_or_body() {
+        let path = "/rustfs/admin/v3/ilm/transition/state/reconcile?bucket=test-bucket&object=key&versionId=null";
+        let inspect_err = LegacyTransitionStateReconcileInspectHandler {}
+            .call(manual_transition_job_request(Method::GET, path), Params::new())
+            .await
+            .expect_err("inspect handler must reject unsigned requests");
+        assert_eq!(inspect_err.code(), &S3ErrorCode::InvalidRequest);
+        assert_eq!(inspect_err.message(), Some("authentication required"));
+
+        let apply_err = LegacyTransitionStateReconcileApplyHandler {}
+            .call(manual_transition_job_request(Method::POST, path), Params::new())
+            .await
+            .expect_err("apply handler must reject unsigned requests");
+        assert_eq!(apply_err.code(), &S3ErrorCode::InvalidRequest);
+        assert_eq!(apply_err.message(), Some("authentication required"));
+    }
+
     #[test]
     fn manual_transition_job_handlers_authorize_validate_and_load_store() {
         let src = include_str!("ilm_transition.rs");

rustfs/src/admin/route_policy.rs

@@ -520,6 +520,18 @@ pub const ADMIN_ROUTE_POLICY_SPECS: &[AdminRouteSpec] = &[
         SET_TIER,
         RouteRiskLevel::High,
     ),
+    admin(
+        HttpMethod::Get,
+        "/rustfs/admin/v3/ilm/transition/state/reconcile",
+        LIST_TIER,
+        RouteRiskLevel::High,
+    ),
+    admin(
+        HttpMethod::Post,
+        "/rustfs/admin/v3/ilm/transition/state/reconcile",
+        SET_TIER,
+        RouteRiskLevel::High,
+    ),
     admin(
         HttpMethod::Get,
         "/rustfs/admin/v3/audit/target/list",
@@ -2164,11 +2176,15 @@ mod tests {
         assert_action(HttpMethod::Delete, "/rustfs/admin/v3/ilm/transition/jobs/{job_id}", SET_TIER);
         assert_action(HttpMethod::Get, "/rustfs/admin/v3/ilm/transition/reconcile/{transaction_id}", LIST_TIER);
         assert_action(HttpMethod::Post, "/rustfs/admin/v3/ilm/transition/reconcile/{transaction_id}", SET_TIER);
+        assert_action(HttpMethod::Get, "/rustfs/admin/v3/ilm/transition/state/reconcile", LIST_TIER);
+        assert_action(HttpMethod::Post, "/rustfs/admin/v3/ilm/transition/state/reconcile", SET_TIER);
         assert_not_action(HttpMethod::Post, "/rustfs/admin/v3/ilm/transition/run", SERVER_INFO);
         assert_not_action(HttpMethod::Get, "/rustfs/admin/v3/ilm/transition/jobs/{job_id}", SERVER_INFO);
         assert_not_action(HttpMethod::Delete, "/rustfs/admin/v3/ilm/transition/jobs/{job_id}", SERVER_INFO);
         assert_not_action(HttpMethod::Get, "/rustfs/admin/v3/ilm/transition/reconcile/{transaction_id}", SET_TIER);
         assert_not_action(HttpMethod::Post, "/rustfs/admin/v3/ilm/transition/reconcile/{transaction_id}", LIST_TIER);
+        assert_not_action(HttpMethod::Get, "/rustfs/admin/v3/ilm/transition/state/reconcile", SET_TIER);
+        assert_not_action(HttpMethod::Post, "/rustfs/admin/v3/ilm/transition/state/reconcile", LIST_TIER);
     }
 
     #[test]

rustfs/src/admin/route_registration_test.rs

@@ -225,6 +225,8 @@ fn expected_admin_route_matrix() -> Vec<RouteMatrixEntry> {
             "/v3/ilm/transition/reconcile/{transaction_id}",
             "/v3/ilm/transition/reconcile/11111111-1111-4111-8111-111111111111",
         ),
+        admin_route(Method::GET, "/v3/ilm/transition/state/reconcile"),
+        admin_route(Method::POST, "/v3/ilm/transition/state/reconcile"),
         admin_route_sample(
             Method::DELETE,
             "/v3/ilm/transition/jobs/{job_id}",
@@ -951,6 +953,8 @@ fn test_register_routes_cover_representative_admin_paths() {
         Method::POST,
         &admin_path("/v3/ilm/transition/reconcile/11111111-1111-4111-8111-111111111111"),
     );
+    assert_route(&router, Method::GET, &admin_path("/v3/ilm/transition/state/reconcile"));
+    assert_route(&router, Method::POST, &admin_path("/v3/ilm/transition/state/reconcile"));
 
     assert_route(&router, Method::GET, &table_catalog_path("/config"));
     assert_route(&router, Method::PUT, &table_catalog_path("/buckets/analytics"));

rustfs/src/admin/storage_api.rs

@@ -223,6 +223,10 @@ pub(crate) mod lifecycle {
         renew_manual_transition_job_lease_if_owned, request_manual_transition_job_cancel, save_manual_transition_job_record,
         update_manual_transition_job_record,
     };
+    pub(crate) use crate::storage::storage_api::ecstore_bucket::lifecycle::legacy_transition_state_reconcile::{
+        LegacyTransitionStateReconcileError, LegacyTransitionStateReconcileRequest, LegacyTransitionStateReconcileResponse,
+        LegacyTransitionStateReconcileSelector,
+    };
     pub(crate) type ManualTransitionCancelCheck =
         super::ecstore_bucket::lifecycle::bucket_lifecycle_ops::ManualTransitionCancelCheck;
     pub(crate) type ManualTransitionQueueSnapshot =