fix(scanner): isolate corrupt cycle state (#6354)

* fix(scanner): isolate corrupt cycle state

* fix(scanner): preserve newer state during recovery reset

* fix(scanner): fence recovery reset state

* fix(scanner): reject terminal recovery epochs

* fix(scanner): reject trailing cycle state bytes

* fix(scanner): reject terminal leadership epochs

* fix(scanner): retain recovery wake notifications

* fix(scanner): recover from oversized markers

crates/scanner/src/data_usage_define.rs

@@ -125,6 +125,34 @@ pub(crate) async fn read_config_with_revision<S: ScannerObjectIO>(
     }
 }
 
+/// Read only the object revision without materializing its body.
+pub(crate) async fn read_config_revision<S: ScannerObjectIO>(store: Arc<S>, path: &str) -> StorageResult<DataUsageCacheRevision> {
+    match store
+        .get_object_reader(
+            RUSTFS_META_BUCKET,
+            path,
+            None,
+            HeaderMap::new(),
+            &ObjectOptions {
+                no_lock: true,
+                ..Default::default()
+            },
+        )
+        .await
+    {
+        Ok(reader) => reader
+            .object_info
+            .etag
+            .filter(|etag| !etag.is_empty())
+            .map(DataUsageCacheRevision::Etag)
+            .ok_or_else(|| StorageError::other(format!("scanner config object {path} has no ETag"))),
+        Err(Error::FileNotFound | Error::VolumeNotFound | Error::ObjectNotFound(_, _) | Error::BucketNotFound(_)) => {
+            Ok(DataUsageCacheRevision::Missing)
+        }
+        Err(err) => Err(err),
+    }
+}
+
 #[derive(Clone, Debug)]
 pub(crate) struct DataUsageCacheRevisions {
     main: DataUsageCacheRevision,
@@ -146,6 +174,11 @@ pub static LEGACY_DATA_USAGE_OBJ_NAME_PATH: LazyLock<String> =
 pub static DATA_USAGE_BLOOM_NAME_PATH: LazyLock<String> =
     LazyLock::new(|| format!("{BUCKET_META_PREFIX}{SLASH_SEPARATOR}{DATA_USAGE_BLOOM_NAME}"));
 
+/// Durable companion object for a cycle-state object which cannot be decoded.
+/// The primary object is deliberately never replaced or deleted by recovery.
+pub static DATA_USAGE_BLOOM_RECOVERY_PATH: LazyLock<String> =
+    LazyLock::new(|| format!("{}.recovery-required.json", DATA_USAGE_BLOOM_NAME_PATH.as_str()));
+
 pub static BACKGROUND_HEAL_INFO_PATH: LazyLock<String> =
     LazyLock::new(|| format!("{BUCKET_META_PREFIX}{SLASH_SEPARATOR}.background-heal.json"));
 

crates/scanner/src/data_usage_define/persistence.rs

@@ -74,7 +74,7 @@ impl DataUsageCache {
         let loaded = Self::load_cache(store.clone(), name).await?;
         let backup = match loaded.backup_revision {
             Some(revision) => Some(revision),
-            None => match Self::revision_for_path(store, &backup_path).await {
+            None => match read_config_revision(store, &backup_path).await {
                 Ok(revision) => Some(revision),
                 Err(err) => {
                     counter!(METRIC_CACHE_BACKUP_REVISION_FAILURE_TOTAL).increment(1);
@@ -336,33 +336,6 @@ impl DataUsageCache {
         }
     }
 
-    async fn revision_for_path<S: ScannerObjectIO>(store: Arc<S>, path: &str) -> StorageResult<DataUsageCacheRevision> {
-        match store
-            .get_object_reader(
-                RUSTFS_META_BUCKET,
-                path,
-                None,
-                HeaderMap::new(),
-                &ObjectOptions {
-                    no_lock: true,
-                    ..Default::default()
-                },
-            )
-            .await
-        {
-            Ok(reader) => reader
-                .object_info
-                .etag
-                .filter(|etag| !etag.is_empty())
-                .map(DataUsageCacheRevision::Etag)
-                .ok_or_else(|| StorageError::other(format!("scanner cache object {path} has no ETag"))),
-            Err(Error::FileNotFound | Error::VolumeNotFound | Error::ObjectNotFound(_, _) | Error::BucketNotFound(_)) => {
-                Ok(DataUsageCacheRevision::Missing)
-            }
-            Err(err) => Err(err),
-        }
-    }
-
     pub(super) fn cache_save_timeout() -> Duration {
         crate::runtime_config::scanner_cache_save_timeout()
     }

crates/scanner/src/lib.rs

@@ -75,7 +75,10 @@ pub use remote_scanner::{
 };
 pub use runtime_config::{apply_scanner_runtime_config, scanner_runtime_config_status, validate_scanner_runtime_config};
 pub use rustfs_common::last_minute;
-pub use scanner::{ScannerCycleScheduleStatus, init_data_scanner, scanner_cycle_schedule_status, scanner_topology_digest};
+pub use scanner::{
+    ScannerCycleRecoveryMarker, ScannerCycleRecoveryStatus, ScannerCycleScheduleStatus, init_data_scanner,
+    reset_scanner_cycle_recovery, scanner_cycle_recovery_status, scanner_cycle_schedule_status, scanner_topology_digest,
+};
 pub use scanner_io::{
     ScannerDirtyUsageAckError, ScannerDirtyUsageState, acknowledge_dirty_usage_generation, clear_dirty_usage_bucket,
     record_dirty_usage_bucket, record_scanner_maintenance_change, scanner_activity_epoch, scanner_dirty_usage_state,

crates/scanner/src/scanner.rs

@@ -20,7 +20,7 @@ use std::sync::{Arc, LazyLock, RwLock};
 
 use crate::data_usage_define::{
     BACKGROUND_HEAL_INFO_PATH, DATA_USAGE_BLOOM_NAME_PATH, DATA_USAGE_OBJ_NAME_PATH, DATA_USAGE_OBSERVED_OBJ_NAME_PATH,
-    DataUsageCache, DataUsageCacheRevision, LEGACY_DATA_USAGE_OBJ_NAME_PATH, read_config_with_revision,
+    DataUsageCache, DataUsageCacheRevision, LEGACY_DATA_USAGE_OBJ_NAME_PATH, read_config_revision, read_config_with_revision,
 };
 use crate::runtime_config::{
     ScannerRuntimeConfig, ScannerRuntimeConfigSource, refresh_scanner_runtime_config_from_global, scanner_bitrot_cycle,
@@ -54,9 +54,7 @@ use rustfs_config::{ENV_SCANNER_CYCLE, ENV_SCANNER_SPEED, ENV_SCANNER_START_DELA
 use rustfs_data_usage::observed_data_usage_is_newer;
 use serde::{Deserialize, Serialize};
 use sha2::{Digest as _, Sha256};
-#[cfg(test)]
-use tokio::sync::Notify;
-use tokio::sync::mpsc;
+use tokio::sync::{Notify, mpsc};
 use tokio::time::{Duration, Instant};
 use tokio_util::sync::CancellationToken;
 use tokio_util::task::AbortOnDropHandle;
@@ -104,6 +102,13 @@ const CLEAN_IDLE_BACKOFF_FACTOR: u32 = 2;
 /// unavailable peer cannot drive a tight retry loop.
 const SCANNER_RETRY_BASE_INTERVAL: Duration = Duration::from_secs(5);
 const SCANNER_RETRY_MAX_INTERVAL: Duration = Duration::from_secs(30 * 60);
+/// A transient backend outage remains self-healing after the short retry
+/// budget is exhausted, but the probe is intentionally sparse until storage
+/// recovers or an operator reset wakes the scanner.
+const SCANNER_CYCLE_RECOVERY_PAUSED_INTERVAL: Duration = Duration::from_secs(5 * 60);
+/// Permanent recovery states still get a sparse status probe so a reset that
+/// races the wait registration cannot leave the scanner asleep forever.
+const SCANNER_CYCLE_RECOVERY_BLOCKED_PROBE_INTERVAL: Duration = Duration::from_secs(5 * 60);
 const SCANNER_LEADER_LOCK_POLL_INTERVAL: Duration = Duration::from_secs(1);
 #[cfg(not(test))]
 const SCANNER_LOCK_LOSS_SHUTDOWN_TIMEOUT: Duration = Duration::from_secs(30);
@@ -125,6 +130,12 @@ type ScannerCycleStatePersistTestHook = (u64, Arc<Notify>);
 static SCANNER_CYCLE_STATE_PERSIST_TEST_HOOK: LazyLock<StdMutex<Option<ScannerCycleStatePersistTestHook>>> =
     LazyLock::new(|| StdMutex::new(None));
 
+static SCANNER_CYCLE_RECOVERY_WAKE: LazyLock<Notify> = LazyLock::new(Notify::new);
+
+pub(super) fn notify_scanner_cycle_recovery_wake() {
+    SCANNER_CYCLE_RECOVERY_WAKE.notify_one();
+}
+
 #[cfg(test)]
 struct ScannerCycleStatePersistTestHookGuard;
 
@@ -576,19 +587,21 @@ pub async fn init_data_scanner(ctx: CancellationToken, storeapi: Arc<ECStore>) {
             tokio::time::sleep(sleep_time).await;
         }
 
+        let mut transient_backoff = ScannerRetryBackoff::default();
+        let mut recovery_retry_count = 0_u32;
         loop {
             if ctx_clone.is_cancelled() {
                 break;
             }
 
-            if let Err(e) = run_data_scanner_with_maintenance_state(
+            let run_result = run_data_scanner_with_maintenance_state(
                 ctx_clone.clone(),
                 storeapi_clone.clone(),
                 startup_features,
                 startup_maintenance_generation,
             )
-            .await
-            {
+            .await;
+            if let Err(e) = &run_result {
                 error!(
                     target: "rustfs::scanner",
                     event = EVENT_SCANNER_CYCLE_STATE,
@@ -599,11 +612,52 @@ pub async fn init_data_scanner(ctx: CancellationToken, storeapi: Arc<ECStore>) {
                     "Scanner runtime iteration failed"
                 );
             }
+            let recovery_status = scanner_cycle_recovery_status();
+            if recovery_status.retryable {
+                recovery_retry_count = recovery_retry_count.saturating_add(1);
+                let _ = record_scanner_cycle_recovery_retry(recovery_retry_count);
+            } else {
+                recovery_retry_count = 0;
+            }
+
+            let recovery_status = scanner_cycle_recovery_status();
+            if recovery_status.state == "paused" {
+                transient_backoff.record_retryable_cycle(false);
+                tokio::select! {
+                    _ = ctx_clone.cancelled() => break,
+                    _ = SCANNER_CYCLE_RECOVERY_WAKE.notified() => {},
+                    _ = tokio::time::sleep(SCANNER_CYCLE_RECOVERY_PAUSED_INTERVAL) => {},
+                }
+                recovery_retry_count = 0;
+                continue;
+            }
+            if !recovery_status.retryable
+                && matches!(recovery_status.state.as_str(), "blocked" | "recovery-required" | "cleanup-pending")
+            {
+                transient_backoff.record_retryable_cycle(false);
+                tokio::select! {
+                    _ = ctx_clone.cancelled() => break,
+                    _ = SCANNER_CYCLE_RECOVERY_WAKE.notified() => {},
+                    _ = tokio::time::sleep(SCANNER_CYCLE_RECOVERY_BLOCKED_PROBE_INTERVAL) => {},
+                }
+                continue;
+            }
+
+            let retry_delay = if recovery_status.retryable || run_result.is_err() {
+                transient_backoff.record_retryable_cycle(true);
+                transient_backoff
+                    .retry_interval(scanner_cycle_interval())
+                    .unwrap_or(SCANNER_RETRY_BASE_INTERVAL)
+            } else {
+                transient_backoff.record_retryable_cycle(false);
+                randomized_cycle_delay()
+            };
             // Backoff before retrying after lock contention or scanner-level failures.
             // Keep this cancellation-aware so shutdown is not delayed by backoff sleep.
             tokio::select! {
                 _ = ctx_clone.cancelled() => break,
-                _ = tokio::time::sleep(randomized_cycle_delay()) => {}
+                _ = SCANNER_CYCLE_RECOVERY_WAKE.notified() => {},
+                _ = tokio::time::sleep(retry_delay) => {}
             }
         }
     });
@@ -1606,40 +1660,22 @@ async fn run_data_scanner_with_maintenance_state(
         observe_scanner_activity(&storeapi, distributed, &mut scanner_activity_seen).await;
     }
 
-    let (buf, mut cycle_revision) = match read_config_with_revision(storeapi.clone(), DATA_USAGE_BLOOM_NAME_PATH.as_str()).await {
-        Ok((buf, revision)) => (buf.unwrap_or_default(), revision),
-        Err(err) => {
-            error!(
-                target: "rustfs::scanner",
-                event = EVENT_SCANNER_PERSIST_STATE,
-                component = LOG_COMPONENT_SCANNER,
-                subsystem = LOG_SUBSYSTEM_RUNTIME,
-                path = %&*DATA_USAGE_BLOOM_NAME_PATH,
-                state = "revision_load_failed",
-                error = %err,
-                "Scanner cycle state revision load failed"
-            );
-            global_metrics().set_cycle(None).await;
-            return Ok(());
-        }
-    };
-    let (mut cycle_info, mut leader_epoch) = match decode_scanner_cycle_state_for_startup(&buf) {
-        Ok(state) => state,
-        Err(err) => {
-            error!(
-                target: "rustfs::scanner",
-                event = EVENT_SCANNER_PERSIST_STATE,
-                component = LOG_COMPONENT_SCANNER,
-                subsystem = LOG_SUBSYSTEM_RUNTIME,
-                path = %&*DATA_USAGE_BLOOM_NAME_PATH,
-                state = "cycle_decode_failed",
-                error = %err,
-                "Scanner stopped because persisted cycle state is invalid"
-            );
-            global_metrics().set_cycle(None).await;
-            return Ok(());
-        }
-    };
+    let (mut cycle_info, mut leader_epoch, mut cycle_revision) =
+        match load_scanner_cycle_state_for_startup(storeapi.clone()).await {
+            ScannerCycleStateStartup::Ready {
+                cycle,
+                leader_epoch,
+                revision,
+            } => (cycle, leader_epoch, revision),
+            ScannerCycleStateStartup::Blocked => {
+                global_metrics().set_cycle(None).await;
+                return Ok(());
+            }
+            ScannerCycleStateStartup::Transient(err) => {
+                global_metrics().set_cycle(None).await;
+                return Err(err);
+            }
+        };
     let usage_floor = match persisted_usage_floor(storeapi.clone()).await {
         Ok(floor) => floor,
         Err(err) => {
@@ -2219,7 +2255,12 @@ pub(crate) use activity::{
 pub(crate) use activity::{ScannerCycleOutcome, scanner_cycle_outcome_with_pending_maintenance};
 #[cfg(test)]
 pub(crate) use cycle_state::encode_scanner_cycle_fence_for_test;
-pub(crate) use cycle_state::{current_scanner_leader_epoch, decode_persisted_scanner_cycle_fence};
+pub use cycle_state::{
+    ScannerCycleRecoveryMarker, ScannerCycleRecoveryStatus, reset_scanner_cycle_recovery, scanner_cycle_recovery_status,
+};
+pub(crate) use cycle_state::{
+    current_scanner_leader_epoch, decode_persisted_scanner_cycle_fence, load_scanner_cycle_state_for_startup,
+};
 pub use heal_info::{BackgroundHealInfo, read_background_heal_info, save_background_heal_info};
 pub use usage_store::store_data_usage_in_backend;
 

crates/scanner/src/scanner/leadership.rs

@@ -196,7 +196,7 @@ pub(super) async fn claim_scanner_leadership(
         if ctx.is_cancelled() {
             return false;
         }
-        let Some(claimed_epoch) = persisted_epoch.checked_add(1) else {
+        let Some(claimed_epoch) = persisted_epoch.checked_add(1).filter(|epoch| *epoch < u64::MAX) else {
             error!(
                 target: "rustfs::scanner",
                 event = EVENT_SCANNER_PERSIST_STATE,

crates/scanner/src/scanner/tests.rs

@@ -15,11 +15,12 @@
 use super::*;
 use crate::EcstoreResult;
 use crate::{
-    Endpoint, EndpointServerPools, Endpoints, InstanceContext, PoolEndpoints, ScannerGetObjectReader as GetObjectReader,
-    ScannerObjectInfo as ObjectInfo, ScannerObjectOptions as ObjectOptions, ScannerPutObjReader as PutObjReader,
-    init_bucket_metadata_sys_for_scanner_tests, init_ecstore_config_for_scanner_tests, init_local_disks_with_instance_ctx,
+    DATA_USAGE_BLOOM_RECOVERY_PATH, Endpoint, EndpointServerPools, Endpoints, InstanceContext, PoolEndpoints,
+    ScannerGetObjectReader as GetObjectReader, ScannerObjectInfo as ObjectInfo, ScannerObjectOptions as ObjectOptions,
+    ScannerPutObjReader as PutObjReader, init_bucket_metadata_sys_for_scanner_tests, init_ecstore_config_for_scanner_tests,
+    init_local_disks_with_instance_ctx,
 };
-use std::collections::HashMap;
+use std::collections::{HashMap, HashSet};
 use std::io::Cursor;
 use std::task::Poll;
 use temp_env::{with_var, with_var_unset};
@@ -117,6 +118,15 @@ async fn scanner_cycle_lock_fence_bounds_uncooperative_shutdown() {
     assert!(cycle_ctx.is_cancelled());
 }
 
+#[tokio::test]
+async fn scanner_cycle_recovery_wake_survives_wait_registration_race() {
+    notify_scanner_cycle_recovery_wake();
+
+    tokio::time::timeout(Duration::from_secs(1), SCANNER_CYCLE_RECOVERY_WAKE.notified())
+        .await
+        .expect("recovery wake should retain a permit until the waiter registers");
+}
+
 struct ScannerDefaultSpeedGuard;
 
 impl ScannerDefaultSpeedGuard {
@@ -151,6 +161,7 @@ impl Drop for ScannerDefaultCycleGuard {
 struct MemoryConfigStore {
     objects: Mutex<HashMap<String, Vec<u8>>>,
     revisions: Mutex<HashMap<String, u64>>,
+    non_regular_objects: Mutex<HashSet<String>>,
     fail_put_number: Mutex<HashMap<String, usize>>,
     object_not_found_put_number: Mutex<HashMap<String, usize>>,
     error_after_commit_put_number: Mutex<HashMap<String, usize>>,
@@ -191,12 +202,16 @@ impl crate::storage_api::scanner_io::ObjectIO for MemoryConfigStore {
             .get(&key)
             .cloned()
             .ok_or(EcstoreError::FileNotFound)?;
-        let revision = *self.revisions.lock().await.entry(key).or_insert(1);
+        let data_len = i64::try_from(data.len()).expect("memory test object length should fit in i64");
+        let revision = *self.revisions.lock().await.entry(key.clone()).or_insert(1);
+        let is_dir = self.non_regular_objects.lock().await.contains(&key);
 
         Ok(GetObjectReader {
             stream: Box::new(Cursor::new(data)),
             object_info: ObjectInfo {
                 etag: Some(format!("memory-{revision}")),
+                size: data_len,
+                is_dir,
                 ..Default::default()
             },
             buffered_body: None,
@@ -797,6 +812,10 @@ fn scanner_cycle_state_decodes_legacy_and_fenced_formats() {
     let (fenced_cycle, fenced_epoch) = decode_scanner_cycle_state(&fenced).expect("fenced cycle state should decode");
     assert_eq!(fenced_cycle.next, 13);
     assert_eq!(fenced_epoch, 7);
+
+    let mut trailing = fenced;
+    trailing.push(0);
+    assert!(decode_scanner_cycle_state(&trailing).is_err());
 }
 
 #[test]
@@ -823,6 +842,840 @@ fn scanner_startup_fails_closed_on_nonempty_corrupt_cycle_state() {
     assert!(encode_scanner_cycle_state(&exhausted, 7).is_err());
 }
 
+#[tokio::test]
+async fn corrupt_cycle_state_is_quarantined_once() {
+    let store = Arc::new(MemoryConfigStore::default());
+    let state_key = memory_config_key(RUSTFS_META_BUCKET, DATA_USAGE_BLOOM_NAME_PATH.as_str());
+    store.objects.lock().await.insert(state_key.clone(), vec![1]);
+    store.revisions.lock().await.insert(state_key.clone(), 7);
+
+    assert!(matches!(
+        load_scanner_cycle_state_for_startup(store.clone()).await,
+        ScannerCycleStateStartup::Blocked
+    ));
+    let marker_key = memory_config_key(RUSTFS_META_BUCKET, DATA_USAGE_BLOOM_RECOVERY_PATH.as_str());
+    let marker_data = store
+        .objects
+        .lock()
+        .await
+        .get(&marker_key)
+        .cloned()
+        .expect("corrupt state must leave a durable recovery marker");
+    let marker: ScannerCycleRecoveryMarker = serde_json::from_slice(&marker_data).expect("marker should be valid JSON");
+    assert_eq!(marker.primary_revision, "memory-7");
+    assert_eq!(marker.path, DATA_USAGE_BLOOM_NAME_PATH.as_str());
+    assert_eq!(marker.quarantine_path, DATA_USAGE_BLOOM_RECOVERY_PATH.as_str());
+    assert_eq!(marker.classification, "corrupt");
+
+    // A second startup sees the matching marker before consuming the poison body.
+    assert!(matches!(
+        load_scanner_cycle_state_for_startup(store.clone()).await,
+        ScannerCycleStateStartup::Blocked
+    ));
+
+    // Replacing the primary object advances its revision; the stale marker must
+    // not quarantine the newer, valid state.
+    let cycle = CurrentCycle {
+        next: 9,
+        ..Default::default()
+    };
+    let encoded = encode_scanner_cycle_state(&cycle, 3).expect("valid state should encode");
+    store.objects.lock().await.insert(state_key.clone(), encoded);
+    store.revisions.lock().await.insert(state_key, 8);
+    assert!(matches!(
+        load_scanner_cycle_state_for_startup(store).await,
+        ScannerCycleStateStartup::Ready {
+            cycle: CurrentCycle { next: 9, .. },
+            leader_epoch: 3,
+            ..
+        }
+    ));
+}
+
+#[tokio::test]
+async fn empty_cycle_state_object_is_quarantined_as_corrupt() {
+    let store = Arc::new(MemoryConfigStore::default());
+    let state_key = memory_config_key(RUSTFS_META_BUCKET, DATA_USAGE_BLOOM_NAME_PATH.as_str());
+    store.objects.lock().await.insert(state_key.clone(), Vec::new());
+    store.revisions.lock().await.insert(state_key, 6);
+
+    assert!(matches!(
+        load_scanner_cycle_state_for_startup(store).await,
+        ScannerCycleStateStartup::Blocked
+    ));
+    assert_eq!(scanner_cycle_recovery_status().classification.as_deref(), Some("corrupt"));
+    assert!(
+        scanner_cycle_recovery_status()
+            .reason
+            .as_deref()
+            .is_some_and(|reason| reason.contains("empty"))
+    );
+}
+
+#[tokio::test]
+async fn future_cycle_state_schema_is_recovery_required() {
+    let store = Arc::new(MemoryConfigStore::default());
+    let state_key = memory_config_key(RUSTFS_META_BUCKET, DATA_USAGE_BLOOM_NAME_PATH.as_str());
+    let mut future = 17_u64.to_le_bytes().to_vec();
+    future.extend_from_slice(b"RSCYC999");
+    future.extend_from_slice(&4_u64.to_le_bytes());
+    future.extend_from_slice(&[0x90]);
+    store.objects.lock().await.insert(state_key.clone(), future);
+    store.revisions.lock().await.insert(state_key, 13);
+
+    assert!(matches!(
+        load_scanner_cycle_state_for_startup(store).await,
+        ScannerCycleStateStartup::Blocked
+    ));
+    assert_eq!(scanner_cycle_recovery_status().classification.as_deref(), Some("future_schema"));
+}
+
+#[tokio::test]
+async fn concurrent_leaders_cannot_quarantine_newer_cycle_state() {
+    let store = Arc::new(MemoryConfigStore::default());
+    let state_key = memory_config_key(RUSTFS_META_BUCKET, DATA_USAGE_BLOOM_NAME_PATH.as_str());
+    store.objects.lock().await.insert(state_key.clone(), vec![1]);
+    store.revisions.lock().await.insert(state_key, 4);
+
+    let (first, second) = tokio::join!(
+        load_scanner_cycle_state_for_startup(store.clone()),
+        load_scanner_cycle_state_for_startup(store.clone()),
+    );
+    assert!(matches!(first, ScannerCycleStateStartup::Blocked));
+    assert!(matches!(second, ScannerCycleStateStartup::Blocked));
+
+    let marker_key = memory_config_key(RUSTFS_META_BUCKET, DATA_USAGE_BLOOM_RECOVERY_PATH.as_str());
+    let marker_data = store
+        .objects
+        .lock()
+        .await
+        .get(&marker_key)
+        .cloned()
+        .expect("one contender must publish the recovery marker");
+    let marker: ScannerCycleRecoveryMarker = serde_json::from_slice(&marker_data).expect("marker should decode");
+    assert_eq!(marker.primary_revision, "memory-4");
+}
+
+#[tokio::test]
+async fn cleanup_pending_marker_blocks_a_rewritten_primary_after_restart() {
+    let store = Arc::new(MemoryConfigStore::default());
+    let state_key = memory_config_key(RUSTFS_META_BUCKET, DATA_USAGE_BLOOM_NAME_PATH.as_str());
+    let marker_key = memory_config_key(RUSTFS_META_BUCKET, DATA_USAGE_BLOOM_RECOVERY_PATH.as_str());
+    let encoded = encode_scanner_cycle_state(
+        &CurrentCycle {
+            next: 12,
+            ..Default::default()
+        },
+        8,
+    )
+    .expect("valid state should encode");
+    store.objects.lock().await.insert(state_key.clone(), encoded);
+    store.revisions.lock().await.insert(state_key, 22);
+    let marker = ScannerCycleRecoveryMarker {
+        schema_version: 1,
+        primary_revision: "memory-21".to_string(),
+        generation: 11,
+        leader_epoch: 7,
+        classification: "corrupt".to_string(),
+        first_detected_at_unix_secs: 1,
+        last_attempt_at_unix_secs: 2,
+        retry_count: 1,
+        reason: "reset in progress".to_string(),
+        path: DATA_USAGE_BLOOM_NAME_PATH.clone(),
+        quarantine_path: DATA_USAGE_BLOOM_RECOVERY_PATH.clone(),
+        state: "cleanup-pending".to_string(),
+    };
+    store
+        .objects
+        .lock()
+        .await
+        .insert(marker_key.clone(), serde_json::to_vec(&marker).expect("marker should encode"));
+    store.revisions.lock().await.insert(marker_key, 3);
+
+    assert!(matches!(
+        load_scanner_cycle_state_for_startup(store).await,
+        ScannerCycleStateStartup::Blocked
+    ));
+    assert_eq!(scanner_cycle_recovery_status().state, "cleanup-pending");
+}
+
+#[test]
+fn full_rescan_reset_accepts_unknown_marker_fields_without_trusting_cursor() {
+    let marker = br#"{
+        "schema_version": 99,
+        "primary_revision": "memory-7",
+        "generation": 9000,
+        "leader_epoch": 9000,
+        "classification": "new-future-classification",
+        "first_detected_at_unix_secs": 1,
+        "last_attempt_at_unix_secs": 2,
+        "retry_count": 9,
+        "reason": "future marker",
+        "path": "buckets/.bloomcycle.bin",
+        "quarantine_path": "buckets/.bloomcycle.bin.recovery-required.json",
+        "future_field": {"cursor": "untrusted"}
+    }"#;
+    let decoded =
+        super::cycle_state::decode_recovery_marker_for_reset(marker, &DataUsageCacheRevision::Etag("memory-3".to_string()))
+            .expect("full-rescan compatibility decoder should accept additive fields");
+    assert_eq!(decoded.primary_revision, "memory-7");
+    assert_eq!(decoded.classification, "future_schema");
+    assert_eq!(decoded.generation, 0);
+    assert_eq!(decoded.leader_epoch, 0);
+    assert_eq!(decoded.state, "blocked");
+
+    let malformed =
+        super::cycle_state::decode_recovery_marker_for_reset(b"{not-json", &DataUsageCacheRevision::Etag("memory-4".to_string()))
+            .expect("a full-rescan reset must recover even when the marker is malformed");
+    assert!(malformed.primary_revision.is_empty());
+    assert_eq!(malformed.classification, "future_schema");
+}
+
+#[tokio::test]
+async fn full_rescan_reset_rebuilds_after_malformed_marker_without_trusting_cursor() {
+    let (_temp_dir, store) = setup_scanner_cycle_store().await;
+    save_config(store.clone(), DATA_USAGE_BLOOM_NAME_PATH.as_str(), vec![0xff, 0x00, 0x01])
+        .await
+        .expect("corrupt cycle state should be persisted");
+    save_config(store.clone(), DATA_USAGE_BLOOM_RECOVERY_PATH.as_str(), br#"{not-json"#.to_vec())
+        .await
+        .expect("malformed marker should be persisted");
+
+    reset_scanner_cycle_recovery(CancellationToken::new(), store.clone())
+        .await
+        .expect("full-rescan reset should recover malformed marker");
+
+    let state = read_config(store.clone(), DATA_USAGE_BLOOM_NAME_PATH.as_str())
+        .await
+        .expect("rebuilt cycle state should remain durable");
+    let (cycle, leader_epoch) = decode_scanner_cycle_state(&state).expect("rebuilt cycle state should decode");
+    assert_eq!(cycle.next, 0, "reset must use the verified usage floor, not marker cursor");
+    assert_eq!(leader_epoch, 1);
+    assert!(matches!(
+        read_config(store, DATA_USAGE_BLOOM_RECOVERY_PATH.as_str()).await,
+        Err(EcstoreError::ConfigNotFound)
+    ));
+}
+
+#[tokio::test]
+async fn full_rescan_reset_ignores_epoch_from_malformed_future_primary() {
+    let (_temp_dir, store) = setup_scanner_cycle_store().await;
+    let mut future_primary = vec![0; 24];
+    future_primary[8..16].copy_from_slice(b"RSCY9999");
+    future_primary[16..24].copy_from_slice(&u64::MAX.to_le_bytes());
+    save_config(store.clone(), DATA_USAGE_BLOOM_NAME_PATH.as_str(), future_primary)
+        .await
+        .expect("future cycle state should be persisted");
+    save_config(store.clone(), DATA_USAGE_BLOOM_RECOVERY_PATH.as_str(), br#"{not-json"#.to_vec())
+        .await
+        .expect("malformed marker should be persisted");
+
+    reset_scanner_cycle_recovery(CancellationToken::new(), store.clone())
+        .await
+        .expect("full-rescan reset should recover malformed future state");
+
+    let state = read_config(store.clone(), DATA_USAGE_BLOOM_NAME_PATH.as_str())
+        .await
+        .expect("rebuilt cycle state should remain durable");
+    let (_, leader_epoch) = decode_scanner_cycle_state(&state).expect("rebuilt cycle state should decode");
+    assert_eq!(leader_epoch, 1, "invalid persisted bytes must not raise the recovery epoch");
+    assert!(matches!(
+        read_config(store, DATA_USAGE_BLOOM_RECOVERY_PATH.as_str()).await,
+        Err(EcstoreError::ConfigNotFound)
+    ));
+}
+
+#[tokio::test]
+async fn ecstore_exact_recovery_marker_delete_honors_etag() {
+    let (_temp_dir, store) = setup_scanner_cycle_store().await;
+    save_config(store.clone(), DATA_USAGE_BLOOM_RECOVERY_PATH.as_str(), b"marker-v1".to_vec())
+        .await
+        .expect("initial recovery marker should be persisted");
+    let (_, stale_revision) = read_config_with_revision(store.clone(), DATA_USAGE_BLOOM_RECOVERY_PATH.as_str())
+        .await
+        .expect("initial marker revision should load");
+    save_config(store.clone(), DATA_USAGE_BLOOM_RECOVERY_PATH.as_str(), b"marker-v2".to_vec())
+        .await
+        .expect("replacement recovery marker should be persisted");
+
+    let delete_result = store
+        .delete_config_object(
+            RUSTFS_META_BUCKET,
+            DATA_USAGE_BLOOM_RECOVERY_PATH.as_str(),
+            ObjectOptions {
+                http_preconditions: Some(stale_revision.preconditions()),
+                ..Default::default()
+            },
+        )
+        .await;
+    assert!(matches!(delete_result, Err(EcstoreError::PreconditionFailed)));
+    assert_eq!(
+        read_config(store, DATA_USAGE_BLOOM_RECOVERY_PATH.as_str())
+            .await
+            .expect("replacement marker should remain durable"),
+        b"marker-v2"
+    );
+}
+
+#[tokio::test]
+async fn full_rescan_reset_rejects_corrupt_primary_under_stale_blocked_marker() {
+    let (_temp_dir, store) = setup_scanner_cycle_store().await;
+    let corrupt_primary = vec![0xff, 0x00, 0x01];
+    save_config(store.clone(), DATA_USAGE_BLOOM_NAME_PATH.as_str(), corrupt_primary.clone())
+        .await
+        .expect("corrupt cycle state should be persisted");
+    let (_, primary_revision) = read_config_with_revision(store.clone(), DATA_USAGE_BLOOM_NAME_PATH.as_str())
+        .await
+        .expect("primary revision should load");
+    let marker = ScannerCycleRecoveryMarker {
+        schema_version: 1,
+        primary_revision: "memory-stale".to_string(),
+        generation: 1,
+        leader_epoch: 1,
+        classification: "corrupt".to_string(),
+        first_detected_at_unix_secs: 1,
+        last_attempt_at_unix_secs: 2,
+        retry_count: 1,
+        reason: "blocked primary changed".to_string(),
+        path: DATA_USAGE_BLOOM_NAME_PATH.clone(),
+        quarantine_path: DATA_USAGE_BLOOM_RECOVERY_PATH.clone(),
+        state: "blocked".to_string(),
+    };
+    let marker_data = serde_json::to_vec(&marker).expect("blocked marker should encode");
+    save_config(store.clone(), DATA_USAGE_BLOOM_RECOVERY_PATH.as_str(), marker_data.clone())
+        .await
+        .expect("blocked marker should be persisted");
+
+    assert!(
+        reset_scanner_cycle_recovery(CancellationToken::new(), store.clone())
+            .await
+            .is_err(),
+        "a strict marker must fail closed when its primary revision changed"
+    );
+    assert_eq!(
+        read_config(store.clone(), DATA_USAGE_BLOOM_NAME_PATH.as_str())
+            .await
+            .expect("primary should remain readable"),
+        corrupt_primary
+    );
+    assert_eq!(
+        read_config(store, DATA_USAGE_BLOOM_RECOVERY_PATH.as_str())
+            .await
+            .expect("blocked marker should remain durable"),
+        marker_data
+    );
+    assert!(!matches!(primary_revision, DataUsageCacheRevision::Missing));
+}
+
+#[tokio::test]
+async fn full_rescan_reset_preserves_valid_primary_when_marker_is_malformed() {
+    let (_temp_dir, store) = setup_scanner_cycle_store().await;
+    let primary = CurrentCycle {
+        next: 42,
+        ..Default::default()
+    };
+    let old_primary_data = encode_scanner_cycle_state(&primary, 7).expect("valid cycle state should encode");
+    save_config(store.clone(), DATA_USAGE_BLOOM_NAME_PATH.as_str(), old_primary_data.clone())
+        .await
+        .expect("valid cycle state should be persisted");
+    let (_, old_primary_revision) = read_config_with_revision(store.clone(), DATA_USAGE_BLOOM_NAME_PATH.as_str())
+        .await
+        .expect("primary state revision should load");
+    let old_usage = DataUsageInfo {
+        scanner_epoch: Some(7),
+        scanner_cycle: Some(41),
+        ..Default::default()
+    };
+    let old_usage_data = serde_json::to_vec(&old_usage).expect("usage snapshot should encode");
+    save_config(store.clone(), DATA_USAGE_OBJ_NAME_PATH.as_str(), old_usage_data.clone())
+        .await
+        .expect("usage snapshot should be persisted");
+    let (_, old_usage_revision) = read_config_with_revision(store.clone(), DATA_USAGE_OBJ_NAME_PATH.as_str())
+        .await
+        .expect("usage snapshot revision should load");
+    save_config(store.clone(), DATA_USAGE_BLOOM_RECOVERY_PATH.as_str(), b"{not-json".to_vec())
+        .await
+        .expect("malformed marker should be persisted");
+
+    reset_scanner_cycle_recovery(CancellationToken::new(), store.clone())
+        .await
+        .expect("reset should clear a stale malformed marker");
+
+    let state = read_config(store.clone(), DATA_USAGE_BLOOM_NAME_PATH.as_str())
+        .await
+        .expect("valid primary should remain durable");
+    let (cycle, leader_epoch) = decode_scanner_cycle_state(&state).expect("primary cycle state should decode");
+    assert_eq!(cycle.next, 42, "reset must not regress an independently fenced primary");
+    assert_eq!(leader_epoch, 8, "reset must advance the preserved primary epoch");
+    let stale_primary_save = save_config_with_preconditions(
+        store.clone(),
+        DATA_USAGE_BLOOM_NAME_PATH.as_str(),
+        old_primary_data,
+        old_primary_revision.preconditions(),
+    )
+    .await;
+    assert!(matches!(stale_primary_save, Err(EcstoreError::PreconditionFailed)));
+    let usage = read_config(store.clone(), DATA_USAGE_OBJ_NAME_PATH.as_str())
+        .await
+        .expect("usage epoch fence should remain durable");
+    assert_eq!(
+        serde_json::from_slice::<DataUsageInfo>(&usage)
+            .expect("fenced usage should decode")
+            .scanner_epoch,
+        Some(8)
+    );
+    let stale_save = save_config_with_preconditions(
+        store.clone(),
+        DATA_USAGE_OBJ_NAME_PATH.as_str(),
+        old_usage_data,
+        old_usage_revision.preconditions(),
+    )
+    .await;
+    assert!(matches!(stale_save, Err(EcstoreError::PreconditionFailed)));
+    assert!(matches!(
+        read_config(store, DATA_USAGE_BLOOM_RECOVERY_PATH.as_str()).await,
+        Err(EcstoreError::ConfigNotFound)
+    ));
+}
+
+#[tokio::test]
+async fn full_rescan_reset_resumes_cleanup_pending_preserved_primary() {
+    let (_temp_dir, store) = setup_scanner_cycle_store().await;
+    let completed_at = Utc::now();
+    let primary = CurrentCycle {
+        current: 3,
+        next: 42,
+        cycle_completed: vec![completed_at],
+        started: completed_at,
+    };
+    save_config(
+        store.clone(),
+        DATA_USAGE_BLOOM_NAME_PATH.as_str(),
+        encode_scanner_cycle_state(&primary, 7).expect("valid cycle state should encode"),
+    )
+    .await
+    .expect("valid cycle state should be persisted");
+    let usage = DataUsageInfo {
+        scanner_epoch: Some(7),
+        scanner_cycle: Some(41),
+        ..Default::default()
+    };
+    save_config(
+        store.clone(),
+        DATA_USAGE_OBJ_NAME_PATH.as_str(),
+        serde_json::to_vec(&usage).expect("usage snapshot should encode"),
+    )
+    .await
+    .expect("usage snapshot should be persisted");
+    let marker = ScannerCycleRecoveryMarker {
+        schema_version: 1,
+        primary_revision: "memory-old".to_string(),
+        generation: 41,
+        leader_epoch: 7,
+        classification: "corrupt".to_string(),
+        first_detected_at_unix_secs: 1,
+        last_attempt_at_unix_secs: 2,
+        retry_count: 1,
+        reason: "reset in progress".to_string(),
+        path: DATA_USAGE_BLOOM_NAME_PATH.clone(),
+        quarantine_path: DATA_USAGE_BLOOM_RECOVERY_PATH.clone(),
+        state: "cleanup-pending".to_string(),
+    };
+    save_config(
+        store.clone(),
+        DATA_USAGE_BLOOM_RECOVERY_PATH.as_str(),
+        serde_json::to_vec(&marker).expect("marker should encode"),
+    )
+    .await
+    .expect("cleanup marker should be persisted");
+
+    reset_scanner_cycle_recovery(CancellationToken::new(), store.clone())
+        .await
+        .expect("reset should resume a cleanup-pending preserved primary");
+
+    let state = read_config(store.clone(), DATA_USAGE_BLOOM_NAME_PATH.as_str())
+        .await
+        .expect("preserved cycle state should remain durable");
+    let (cycle, leader_epoch) = decode_scanner_cycle_state(&state).expect("cycle state should decode");
+    assert_eq!(cycle.current, 3, "cleanup retry must preserve the in-progress cursor");
+    assert_eq!(cycle.next, 42);
+    assert_eq!(cycle.cycle_completed, vec![completed_at]);
+    assert_eq!(cycle.started, completed_at);
+    assert_eq!(leader_epoch, 8);
+    let usage = read_config(store.clone(), DATA_USAGE_OBJ_NAME_PATH.as_str())
+        .await
+        .expect("usage epoch fence should remain durable");
+    assert_eq!(
+        serde_json::from_slice::<DataUsageInfo>(&usage)
+            .expect("usage should decode")
+            .scanner_epoch,
+        Some(8)
+    );
+    assert!(matches!(
+        read_config(store, DATA_USAGE_BLOOM_RECOVERY_PATH.as_str()).await,
+        Err(EcstoreError::ConfigNotFound)
+    ));
+}
+
+#[tokio::test]
+async fn full_rescan_reset_rebuilds_oversized_regular_primary_with_malformed_marker() {
+    let (_temp_dir, store) = setup_scanner_cycle_store().await;
+    save_config(store.clone(), DATA_USAGE_BLOOM_NAME_PATH.as_str(), vec![0; 1024 * 1024 + 1])
+        .await
+        .expect("oversized cycle state should be persisted");
+    save_config(store.clone(), DATA_USAGE_BLOOM_RECOVERY_PATH.as_str(), b"{not-json".to_vec())
+        .await
+        .expect("malformed marker should be persisted");
+
+    reset_scanner_cycle_recovery(CancellationToken::new(), store.clone())
+        .await
+        .expect("explicit full-rescan reset should replace an oversized regular primary");
+
+    let state = read_config(store.clone(), DATA_USAGE_BLOOM_NAME_PATH.as_str())
+        .await
+        .expect("rebuilt cycle state should remain durable");
+    let (cycle, leader_epoch) = decode_scanner_cycle_state(&state).expect("rebuilt cycle state should decode");
+    assert_eq!(cycle.next, 0);
+    assert_eq!(leader_epoch, 1);
+    assert!(matches!(
+        read_config(store, DATA_USAGE_BLOOM_RECOVERY_PATH.as_str()).await,
+        Err(EcstoreError::ConfigNotFound)
+    ));
+}
+
+#[tokio::test]
+async fn full_rescan_reset_rebuilds_oversized_primary_after_cleanup_marker() {
+    let (_temp_dir, store) = setup_scanner_cycle_store().await;
+    save_config(store.clone(), DATA_USAGE_BLOOM_NAME_PATH.as_str(), vec![0; 1024 * 1024 + 1])
+        .await
+        .expect("oversized cycle state should be persisted");
+    let (_, primary_revision) = read_config_with_revision(store.clone(), DATA_USAGE_BLOOM_NAME_PATH.as_str())
+        .await
+        .expect("primary revision should load");
+    let marker = ScannerCycleRecoveryMarker {
+        schema_version: 1,
+        primary_revision: match primary_revision {
+            DataUsageCacheRevision::Etag(etag) => etag,
+            DataUsageCacheRevision::Missing => panic!("primary revision should be present"),
+        },
+        generation: 1,
+        leader_epoch: 1,
+        classification: "corrupt".to_string(),
+        first_detected_at_unix_secs: 1,
+        last_attempt_at_unix_secs: 2,
+        retry_count: 1,
+        reason: "reset in progress".to_string(),
+        path: DATA_USAGE_BLOOM_NAME_PATH.clone(),
+        quarantine_path: DATA_USAGE_BLOOM_RECOVERY_PATH.clone(),
+        state: "cleanup-pending".to_string(),
+    };
+    save_config(
+        store.clone(),
+        DATA_USAGE_BLOOM_RECOVERY_PATH.as_str(),
+        serde_json::to_vec(&marker).expect("cleanup marker should encode"),
+    )
+    .await
+    .expect("cleanup marker should be persisted");
+
+    reset_scanner_cycle_recovery(CancellationToken::new(), store.clone())
+        .await
+        .expect("cleanup retry should rebuild an oversized primary");
+
+    let state = read_config(store.clone(), DATA_USAGE_BLOOM_NAME_PATH.as_str())
+        .await
+        .expect("rebuilt cycle state should remain durable");
+    let (cycle, leader_epoch) = decode_scanner_cycle_state(&state).expect("rebuilt cycle state should decode");
+    assert_eq!(cycle.next, 0);
+    assert_eq!(leader_epoch, 1);
+    assert!(matches!(
+        read_config(store, DATA_USAGE_BLOOM_RECOVERY_PATH.as_str()).await,
+        Err(EcstoreError::ConfigNotFound)
+    ));
+}
+
+#[tokio::test]
+async fn full_rescan_reset_rebuilds_with_oversized_marker() {
+    let (_temp_dir, store) = setup_scanner_cycle_store().await;
+    save_config(store.clone(), DATA_USAGE_BLOOM_NAME_PATH.as_str(), vec![0xff, 0x00, 0x01])
+        .await
+        .expect("corrupt cycle state should be persisted");
+    save_config(store.clone(), DATA_USAGE_BLOOM_RECOVERY_PATH.as_str(), vec![b'x'; 64 * 1024 + 1])
+        .await
+        .expect("oversized recovery marker should be persisted");
+
+    reset_scanner_cycle_recovery(CancellationToken::new(), store.clone())
+        .await
+        .expect("full-rescan reset should recover an oversized marker");
+
+    let state = read_config(store.clone(), DATA_USAGE_BLOOM_NAME_PATH.as_str())
+        .await
+        .expect("rebuilt cycle state should remain durable");
+    let (_, leader_epoch) = decode_scanner_cycle_state(&state).expect("rebuilt cycle state should decode");
+    assert_eq!(leader_epoch, 1);
+    assert!(matches!(
+        read_config(store, DATA_USAGE_BLOOM_RECOVERY_PATH.as_str()).await,
+        Err(EcstoreError::ConfigNotFound)
+    ));
+}
+
+#[tokio::test]
+async fn full_rescan_reset_rebuilds_with_empty_marker() {
+    let (_temp_dir, store) = setup_scanner_cycle_store().await;
+    save_config(store.clone(), DATA_USAGE_BLOOM_NAME_PATH.as_str(), vec![0xff, 0x00, 0x01])
+        .await
+        .expect("corrupt cycle state should be persisted");
+    save_config(store.clone(), DATA_USAGE_BLOOM_RECOVERY_PATH.as_str(), Vec::new())
+        .await
+        .expect("empty recovery marker should be persisted");
+
+    reset_scanner_cycle_recovery(CancellationToken::new(), store.clone())
+        .await
+        .expect("full-rescan reset should recover an empty marker");
+
+    let state = read_config(store.clone(), DATA_USAGE_BLOOM_NAME_PATH.as_str())
+        .await
+        .expect("rebuilt cycle state should remain durable");
+    let (_, leader_epoch) = decode_scanner_cycle_state(&state).expect("rebuilt cycle state should decode");
+    assert_eq!(leader_epoch, 1);
+    assert!(matches!(
+        read_config(store, DATA_USAGE_BLOOM_RECOVERY_PATH.as_str()).await,
+        Err(EcstoreError::ConfigNotFound)
+    ));
+}
+
+#[tokio::test]
+async fn full_rescan_reset_keeps_cleanup_marker_when_preserved_epoch_is_exhausted() {
+    let (_temp_dir, store) = setup_scanner_cycle_store().await;
+    let primary = CurrentCycle {
+        next: 42,
+        ..Default::default()
+    };
+    save_config(
+        store.clone(),
+        DATA_USAGE_BLOOM_NAME_PATH.as_str(),
+        encode_scanner_cycle_state(&primary, u64::MAX).expect("valid cycle state should encode"),
+    )
+    .await
+    .expect("valid cycle state should be persisted");
+    save_config(store.clone(), DATA_USAGE_BLOOM_RECOVERY_PATH.as_str(), b"{not-json".to_vec())
+        .await
+        .expect("malformed marker should be persisted");
+
+    assert!(
+        reset_scanner_cycle_recovery(CancellationToken::new(), store.clone())
+            .await
+            .is_err()
+    );
+
+    let marker = read_config(store.clone(), DATA_USAGE_BLOOM_RECOVERY_PATH.as_str())
+        .await
+        .expect("cleanup marker should remain durable");
+    assert_eq!(
+        serde_json::from_slice::<ScannerCycleRecoveryMarker>(&marker)
+            .expect("cleanup marker should decode")
+            .state,
+        "cleanup-pending"
+    );
+    assert!(matches!(
+        load_scanner_cycle_state_for_startup(store).await,
+        ScannerCycleStateStartup::Blocked
+    ));
+}
+
+#[tokio::test]
+async fn full_rescan_reset_rejects_preserved_epoch_that_would_be_terminal() {
+    let (_temp_dir, store) = setup_scanner_cycle_store().await;
+    let primary = CurrentCycle {
+        next: 42,
+        ..Default::default()
+    };
+    save_config(
+        store.clone(),
+        DATA_USAGE_BLOOM_NAME_PATH.as_str(),
+        encode_scanner_cycle_state(&primary, u64::MAX - 1).expect("valid cycle state should encode"),
+    )
+    .await
+    .expect("valid cycle state should be persisted");
+    save_config(store.clone(), DATA_USAGE_BLOOM_RECOVERY_PATH.as_str(), b"{not-json".to_vec())
+        .await
+        .expect("malformed marker should be persisted");
+
+    assert!(
+        reset_scanner_cycle_recovery(CancellationToken::new(), store.clone())
+            .await
+            .is_err(),
+        "reset must not persist the terminal leader epoch"
+    );
+
+    let marker = read_config(store, DATA_USAGE_BLOOM_RECOVERY_PATH.as_str())
+        .await
+        .expect("cleanup marker should remain durable");
+    assert_eq!(
+        serde_json::from_slice::<ScannerCycleRecoveryMarker>(&marker)
+            .expect("cleanup marker should decode")
+            .state,
+        "cleanup-pending"
+    );
+}
+
+#[tokio::test]
+async fn full_rescan_reset_rejects_usage_floor_that_would_be_terminal() {
+    let (_temp_dir, store) = setup_scanner_cycle_store().await;
+    save_config(store.clone(), DATA_USAGE_BLOOM_NAME_PATH.as_str(), vec![0xff, 0x00, 0x01])
+        .await
+        .expect("corrupt cycle state should be persisted");
+    save_config(
+        store.clone(),
+        DATA_USAGE_OBJ_NAME_PATH.as_str(),
+        serde_json::to_vec(&DataUsageInfo {
+            scanner_epoch: Some(u64::MAX - 1),
+            ..Default::default()
+        })
+        .expect("usage floor should encode"),
+    )
+    .await
+    .expect("usage floor should be persisted");
+    save_config(store.clone(), DATA_USAGE_BLOOM_RECOVERY_PATH.as_str(), b"{not-json".to_vec())
+        .await
+        .expect("malformed marker should be persisted");
+
+    assert!(
+        reset_scanner_cycle_recovery(CancellationToken::new(), store.clone())
+            .await
+            .is_err(),
+        "reset must not persist the terminal leader epoch"
+    );
+    assert_eq!(
+        read_config(store, DATA_USAGE_BLOOM_RECOVERY_PATH.as_str())
+            .await
+            .expect("recovery marker should remain durable"),
+        b"{not-json"
+    );
+}
+
+#[tokio::test]
+async fn full_rescan_reset_rebuilds_empty_primary_with_malformed_marker() {
+    let (_temp_dir, store) = setup_scanner_cycle_store().await;
+    save_config(store.clone(), DATA_USAGE_BLOOM_NAME_PATH.as_str(), Vec::new())
+        .await
+        .expect("empty cycle state should be persisted");
+    save_config(store.clone(), DATA_USAGE_BLOOM_RECOVERY_PATH.as_str(), b"{not-json".to_vec())
+        .await
+        .expect("malformed marker should be persisted");
+
+    reset_scanner_cycle_recovery(CancellationToken::new(), store.clone())
+        .await
+        .expect("explicit full-rescan reset should replace an empty primary");
+
+    let state = read_config(store.clone(), DATA_USAGE_BLOOM_NAME_PATH.as_str())
+        .await
+        .expect("rebuilt cycle state should remain durable");
+    let (cycle, leader_epoch) = decode_scanner_cycle_state(&state).expect("rebuilt cycle state should decode");
+    assert_eq!(cycle.next, 0);
+    assert_eq!(leader_epoch, 1);
+    assert!(matches!(
+        read_config(store, DATA_USAGE_BLOOM_RECOVERY_PATH.as_str()).await,
+        Err(EcstoreError::ConfigNotFound)
+    ));
+}
+
+#[tokio::test]
+async fn full_rescan_reset_rebuilds_when_primary_cycle_state_is_missing() {
+    let (_temp_dir, store) = setup_scanner_cycle_store().await;
+    let marker = ScannerCycleRecoveryMarker {
+        schema_version: 1,
+        primary_revision: "memory-missing".to_string(),
+        generation: u64::MAX,
+        leader_epoch: u64::MAX,
+        classification: "corrupt".to_string(),
+        first_detected_at_unix_secs: 1,
+        last_attempt_at_unix_secs: 2,
+        retry_count: 0,
+        reason: "missing primary".to_string(),
+        path: DATA_USAGE_BLOOM_NAME_PATH.clone(),
+        quarantine_path: DATA_USAGE_BLOOM_RECOVERY_PATH.clone(),
+        state: "blocked".to_string(),
+    };
+    save_config(
+        store.clone(),
+        DATA_USAGE_BLOOM_RECOVERY_PATH.as_str(),
+        serde_json::to_vec(&marker).expect("marker should encode"),
+    )
+    .await
+    .expect("marker should be persisted");
+
+    reset_scanner_cycle_recovery(CancellationToken::new(), store.clone())
+        .await
+        .expect("full-rescan reset should recreate missing primary");
+    let state = read_config(store.clone(), DATA_USAGE_BLOOM_NAME_PATH.as_str())
+        .await
+        .expect("missing primary should be rebuilt");
+    let (cycle, leader_epoch) = decode_scanner_cycle_state(&state).expect("rebuilt cycle state should decode");
+    assert_eq!(cycle.next, 0);
+    assert_eq!(leader_epoch, 1);
+    assert!(matches!(
+        read_config(store, DATA_USAGE_BLOOM_RECOVERY_PATH.as_str()).await,
+        Err(EcstoreError::ConfigNotFound)
+    ));
+}
+
+#[tokio::test]
+async fn corrupt_cycle_state_rename_or_marker_failure_stays_recovery_required() {
+    let store = Arc::new(MemoryConfigStore::default());
+    let state_key = memory_config_key(RUSTFS_META_BUCKET, DATA_USAGE_BLOOM_NAME_PATH.as_str());
+    let marker_key = memory_config_key(RUSTFS_META_BUCKET, DATA_USAGE_BLOOM_RECOVERY_PATH.as_str());
+    store.objects.lock().await.insert(state_key.clone(), vec![1]);
+    store.revisions.lock().await.insert(state_key, 9);
+    store.fail_put_number.lock().await.insert(marker_key, 1);
+
+    assert!(matches!(
+        load_scanner_cycle_state_for_startup(store.clone()).await,
+        ScannerCycleStateStartup::Transient(_)
+    ));
+    let status = scanner_cycle_recovery_status();
+    assert_eq!(status.state, "recovery-required");
+    assert!(status.retryable);
+    assert!(
+        store
+            .objects
+            .lock()
+            .await
+            .contains_key(&memory_config_key(RUSTFS_META_BUCKET, DATA_USAGE_BLOOM_NAME_PATH.as_str()))
+    );
+}
+
+#[tokio::test]
+async fn oversized_or_symlinked_cycle_state_is_rejected() {
+    let store = Arc::new(MemoryConfigStore::default());
+    let key = memory_config_key(RUSTFS_META_BUCKET, DATA_USAGE_BLOOM_NAME_PATH.as_str());
+    store.objects.lock().await.insert(key.clone(), vec![0; 1024 * 1024 + 1]);
+    store.revisions.lock().await.insert(key.clone(), 11);
+
+    assert!(matches!(
+        load_scanner_cycle_state_for_startup(store.clone()).await,
+        ScannerCycleStateStartup::Blocked
+    ));
+    assert_eq!(scanner_cycle_recovery_status().classification.as_deref(), Some("corrupt"));
+    assert!(
+        scanner_cycle_recovery_status()
+            .reason
+            .as_deref()
+            .is_some_and(|reason| reason.contains("oversized"))
+    );
+
+    let marker_key = memory_config_key(RUSTFS_META_BUCKET, DATA_USAGE_BLOOM_RECOVERY_PATH.as_str());
+    store.objects.lock().await.remove(&marker_key);
+    store.objects.lock().await.insert(key.clone(), vec![1]);
+    store.revisions.lock().await.insert(key.clone(), 12);
+    store.non_regular_objects.lock().await.insert(key);
+    // The object contract exposes a non-regular object as `is_dir`; local
+    // backends reject symlink/reparse entries before they become an object.
+    assert!(matches!(
+        load_scanner_cycle_state_for_startup(store).await,
+        ScannerCycleStateStartup::Blocked
+    ));
+}
+
 #[tokio::test]
 async fn scanner_startup_uses_primary_and_backup_usage_floor() {
     let store = Arc::new(MemoryConfigStore::default());
@@ -855,6 +1708,31 @@ async fn scanner_startup_uses_primary_and_backup_usage_floor() {
     assert_eq!(epoch, 11);
 }
 
+#[tokio::test]
+async fn scanner_usage_floor_ignores_older_backup_after_primary_epoch_fence() {
+    let store = Arc::new(MemoryConfigStore::default());
+    let backup_path = format!("{}.bkp", DATA_USAGE_OBJ_NAME_PATH.as_str());
+    for (path, epoch, cycle) in [(DATA_USAGE_OBJ_NAME_PATH.as_str(), 8, 100), (backup_path.as_str(), 7, 10_000)] {
+        store.objects.lock().await.insert(
+            memory_config_key(RUSTFS_META_BUCKET, path),
+            serde_json::to_vec(&DataUsageInfo {
+                scanner_epoch: Some(epoch),
+                scanner_cycle: Some(cycle),
+                ..Default::default()
+            })
+            .expect("usage snapshot should encode"),
+        );
+    }
+
+    assert_eq!(
+        persisted_usage_floor(store).await.expect("usage floor should load"),
+        PersistedUsageFloor {
+            next_cycle: 101,
+            leader_epoch: 8,
+        }
+    );
+}
+
 #[test]
 fn scanner_startup_treats_incomplete_usage_snapshot_as_cold() {
     let mut legacy = complete_usage_with_bucket_count(Some(std::time::SystemTime::now()), 1);
@@ -987,6 +1865,15 @@ async fn scanner_usage_floor_fails_closed_on_corrupt_or_exhausted_usage_state()
 
     assert!(persisted_usage_floor(store.clone()).await.is_err());
 
+    store.objects.lock().await.insert(
+        memory_config_key(RUSTFS_META_BUCKET, DATA_USAGE_OBJ_NAME_PATH.as_str()),
+        br#"{}"#.to_vec(),
+    );
+    assert!(
+        persisted_usage_floor(store.clone()).await.is_err(),
+        "a structurally incomplete usage snapshot must not be treated as an empty floor"
+    );
+
     store.objects.lock().await.insert(
         memory_config_key(RUSTFS_META_BUCKET, DATA_USAGE_OBJ_NAME_PATH.as_str()),
         serde_json::to_vec(&DataUsageInfo {
@@ -1244,6 +2131,22 @@ async fn test_leadership_claim_preserves_usage_epoch_floor_across_old_epoch_conf
     assert_eq!(store.put_counts.lock().await.get(&key), Some(&3));
 }
 
+#[tokio::test]
+async fn test_leadership_claim_rejects_terminal_epoch() {
+    let store = Arc::new(MemoryConfigStore::default());
+    let ctx = CancellationToken::new();
+    let mut revision = DataUsageCacheRevision::Missing;
+    let mut cycle = CurrentCycle {
+        next: 12,
+        ..Default::default()
+    };
+    let mut persisted_epoch = u64::MAX - 1;
+
+    assert!(!claim_scanner_leadership(&ctx, store.clone(), &mut cycle, &mut revision, &mut persisted_epoch).await);
+    assert_eq!(persisted_epoch, u64::MAX - 1);
+    assert!(read_config(store, &DATA_USAGE_BLOOM_NAME_PATH).await.is_err());
+}
+
 #[tokio::test]
 async fn test_leadership_claim_confirms_commit_after_returned_error() {
     let store = Arc::new(MemoryConfigStore::default());
@@ -2975,6 +3878,24 @@ fn superseded_retry_backoff_grows_from_the_default_cycle() {
     }
 }
 
+#[tokio::test(start_paused = true)]
+async fn corrupt_cycle_state_backoff_uses_virtual_clock() {
+    let mut backoff = ScannerRetryBackoff::default();
+    backoff.record_retryable_cycle(true);
+    let first_delay = backoff
+        .retry_interval(Duration::from_secs(60))
+        .expect("the first recovery retry should be scheduled");
+    assert_eq!(first_delay, Duration::from_secs(5));
+
+    let deadline = Instant::now() + first_delay;
+    assert!(Instant::now() < deadline);
+    tokio::time::advance(first_delay).await;
+    assert!(Instant::now() >= deadline);
+
+    backoff.record_retryable_cycle(true);
+    assert_eq!(backoff.retry_interval(Duration::from_secs(60)), Some(Duration::from_secs(10)));
+}
+
 #[test]
 fn scanner_cycle_wait_plan_drives_growth_resets_and_bitrot_cap() {
     let runtime_config = ScannerRuntimeConfig {