fix(ecstore): migrate tier free versions during decommission (#6393)

crates/ecstore/src/set_disk/mod.rs

@@ -228,6 +228,69 @@ pub(super) fn restore_commit_operation_id_from_metadata(metadata: &HashMap<Strin
     restore_operation_id_from_metadata(metadata)
 }
 
+async fn inspect_decommission_tier_free_version_target(
+    disk: &DiskStore,
+    bucket: &str,
+    object: &str,
+    source: &FileInfo,
+) -> Result<bool> {
+    let raw = match disk.read_xl(bucket, object, false).await {
+        Ok(raw) => raw,
+        Err(DiskError::FileNotFound | DiskError::FileVersionNotFound | DiskError::VolumeNotFound) => return Ok(false),
+        Err(err) => return Err(err.into()),
+    };
+    let meta = FileMeta::load(&raw.buf)?;
+    let source_version_id = source.version_id.filter(|version_id| !version_id.is_nil());
+    let mut matching_count = 0;
+    let mut all_matching_versions_equivalent = true;
+    for existing in meta
+        .versions
+        .iter()
+        .filter(|version| version.header.version_id.filter(|version_id| !version_id.is_nil()) == source_version_id)
+    {
+        matching_count += 1;
+        let existing = existing.into_fileinfo(bucket, object, true)?;
+        existing.validate_for_metadata_read()?;
+        if !existing.tier_free_version() || !crate::store::tiered_data_movement_source_matches(source, &existing)? {
+            all_matching_versions_equivalent = false;
+        }
+    }
+    if matching_count == 0 {
+        return Ok(false);
+    }
+    if matching_count == 1 && all_matching_versions_equivalent {
+        return Ok(true);
+    }
+
+    Err(StorageError::DataMovementOverwriteErr(
+        bucket.to_owned(),
+        object.to_owned(),
+        source_version_id.map(|version_id| version_id.to_string()).unwrap_or_default(),
+    ))
+}
+
+fn ensure_decommission_tier_free_version_commit_fence(bucket: &str, object: &str, opts: &ObjectOptions) -> Result<()> {
+    if opts
+        .namespace_lock_fence
+        .as_ref()
+        .is_some_and(NamespaceLockFence::is_lock_lost)
+        || opts
+            .bucket_lifecycle_lock_fence
+            .as_ref()
+            .is_some_and(NamespaceLockFence::is_lock_lost)
+    {
+        return Err(StorageError::NamespaceLockQuorumUnavailable {
+            mode: "decommission_tier_free_version_commit",
+            bucket: bucket.to_string(),
+            object: object.to_string(),
+            required: 1,
+            achieved: 0,
+        });
+    }
+
+    Ok(())
+}
+
 impl SetDisks {
     pub(super) async fn require_current_restore_operation_id(
         &self,
@@ -4686,6 +4749,94 @@ fn resolve_delete_version_state(opts: &ObjectOptions, goi: &ObjectInfo, version_
 }
 
 impl SetDisks {
+    /// Publish an internal tier free-version record without changing its
+    /// delete-marker shape or remote-tier identity. The caller holds the
+    /// source and target object locks; a write quorum is required before the
+    /// source cleanup may remove the original record.
+    #[tracing::instrument(skip(self, fi, opts))]
+    pub(crate) async fn decommission_tier_free_version(
+        &self,
+        bucket: &str,
+        object: &str,
+        fi: &FileInfo,
+        opts: &ObjectOptions,
+    ) -> Result<()> {
+        if !fi.deleted || !fi.tier_free_version() {
+            return Err(Error::other("decommission tier free-version write requires a free version record"));
+        }
+        ensure_decommission_tier_free_version_commit_fence(bucket, object, opts)?;
+
+        let write_quorum = self.default_write_quorum();
+        if self
+            .count_decommission_tier_free_version_equivalents(bucket, object, fi)
+            .await?
+            >= write_quorum
+        {
+            ensure_decommission_tier_free_version_commit_fence(bucket, object, opts)?;
+            return Ok(());
+        }
+        ensure_decommission_tier_free_version_commit_fence(bucket, object, opts)?;
+
+        let disks = self.disks.read().await.clone();
+        let futures = disks.into_iter().map(|disk| {
+            let file_info = fi.clone();
+            async move {
+                if let Some(disk) = disk {
+                    disk.write_metadata("", bucket, object, file_info).await
+                } else {
+                    Err(DiskError::DiskNotFound)
+                }
+            }
+        });
+
+        let mut errs = Vec::new();
+        for result in join_all(futures).await {
+            match result {
+                Ok(_) => errs.push(None),
+                Err(err) => errs.push(Some(err)),
+            }
+        }
+
+        ensure_decommission_tier_free_version_commit_fence(bucket, object, opts)?;
+
+        resolve_tiered_decommission_write_quorum_result(&errs, write_quorum, bucket, object)
+    }
+
+    async fn count_decommission_tier_free_version_equivalents(&self, bucket: &str, object: &str, fi: &FileInfo) -> Result<usize> {
+        // The caller holds the source and target object locks. Inspect every
+        // target disk before an idempotent return or metadata fan-out so a
+        // sub-quorum conflict cannot be hidden by a successful quorum.
+        let disks = self.disks.read().await.clone();
+        let preflight = disks.iter().map(|disk| async {
+            match disk {
+                Some(disk) => inspect_decommission_tier_free_version_target(disk, bucket, object, fi).await,
+                None => Ok(false),
+            }
+        });
+        let mut equivalent = 0;
+        for result in join_all(preflight).await {
+            if result? {
+                equivalent += 1;
+            }
+        }
+        Ok(equivalent)
+    }
+
+    pub(crate) async fn has_decommission_tier_free_version_write_quorum(
+        &self,
+        bucket: &str,
+        object: &str,
+        fi: &FileInfo,
+        opts: &ObjectOptions,
+    ) -> Result<bool> {
+        ensure_decommission_tier_free_version_commit_fence(bucket, object, opts)?;
+        let equivalent = self
+            .count_decommission_tier_free_version_equivalents(bucket, object, fi)
+            .await?;
+        ensure_decommission_tier_free_version_commit_fence(bucket, object, opts)?;
+        Ok(equivalent >= self.default_write_quorum())
+    }
+
     #[tracing::instrument(skip(self, fi, opts))]
     pub(crate) async fn decommission_tiered_object(
         &self,
@@ -9916,6 +10067,147 @@ mod tests {
         assert_ne!(updated.erasure.distribution, original.erasure.distribution);
     }
 
+    #[tokio::test]
+    async fn decommission_tier_free_version_preserves_remote_identity() {
+        let set_disks = make_local_bucket_test_set_disks().await;
+        let bucket = "free-version-decommission";
+        let object = "object.txt";
+        set_disks
+            .make_bucket(bucket, &MakeBucketOptions::default())
+            .await
+            .expect("target bucket should exist before free-version migration");
+        let version_id = Uuid::new_v4();
+        let mut free_version = FileInfo {
+            name: object.to_string(),
+            volume: bucket.to_string(),
+            version_id: Some(version_id),
+            mod_time: Some(time::OffsetDateTime::now_utc()),
+            deleted: true,
+            transition_tier: "WARM-TIER".to_string(),
+            transitioned_objname: "remote/object".to_string(),
+            ..Default::default()
+        };
+        free_version.set_tier_free_version();
+        // Decoded free versions always carry the on-disk free-version
+        // suffix alongside the in-memory tier marker; mirror that here so
+        // the record satisfies delete-marker metadata validation.
+        rustfs_utils::http::metadata_compat::insert_str(
+            &mut free_version.metadata,
+            rustfs_utils::http::metadata_compat::SUFFIX_FREE_VERSION,
+            String::new(),
+        );
+
+        set_disks
+            .decommission_tier_free_version(bucket, object, &free_version, &ObjectOptions::default())
+            .await
+            .expect("free-version metadata should reach the target quorum");
+        set_disks
+            .decommission_tier_free_version(bucket, object, &free_version, &ObjectOptions::default())
+            .await
+            .expect("replaying the same free-version metadata should be idempotent");
+
+        let versions = set_disks
+            .load_file_info_versions_exact(bucket, object)
+            .await
+            .expect("migrated free-version metadata should decode")
+            .expect("migrated free-version metadata should exist");
+        let migrated = versions
+            .versions
+            .iter()
+            .find(|version| version.version_id == Some(version_id))
+            .expect("free version should be present on the target");
+
+        assert_eq!(
+            versions
+                .versions
+                .iter()
+                .filter(|version| version.version_id == Some(version_id))
+                .count(),
+            1
+        );
+        assert!(migrated.tier_free_version());
+        assert_eq!(migrated.transition_tier, "WARM-TIER");
+        assert_eq!(migrated.transitioned_objname, "remote/object");
+    }
+
+    #[tokio::test]
+    async fn decommission_tier_free_version_resume_requires_write_quorum() {
+        let set_disks = make_local_bucket_test_set_disks_with_drive_count(4).await;
+        let bucket = "free-version-decommission-resume";
+        let object = "object.txt";
+        set_disks
+            .make_bucket(bucket, &MakeBucketOptions::default())
+            .await
+            .expect("target bucket should exist before free-version migration");
+        let mut free_version = FileInfo {
+            name: object.to_string(),
+            volume: bucket.to_string(),
+            version_id: Some(Uuid::new_v4()),
+            mod_time: Some(time::OffsetDateTime::now_utc()),
+            deleted: true,
+            transition_tier: "WARM-TIER".to_string(),
+            transitioned_objname: "remote/object".to_string(),
+            ..Default::default()
+        };
+        free_version.set_tier_free_version();
+        // Decoded free versions always carry the on-disk free-version
+        // suffix alongside the in-memory tier marker; mirror that here so
+        // the record satisfies delete-marker metadata validation.
+        rustfs_utils::http::metadata_compat::insert_str(
+            &mut free_version.metadata,
+            rustfs_utils::http::metadata_compat::SUFFIX_FREE_VERSION,
+            String::new(),
+        );
+        let opts = ObjectOptions::default();
+
+        let disks = set_disks.get_disks_internal().await;
+        for disk in disks.iter().take(2).flatten() {
+            disk.write_metadata("", bucket, object, free_version.clone())
+                .await
+                .expect("partial first attempt should leave equivalent metadata");
+        }
+        assert!(
+            !set_disks
+                .has_decommission_tier_free_version_write_quorum(bucket, object, &free_version, &opts)
+                .await
+                .expect("partial target metadata should remain valid"),
+            "write-quorum-minus-one must not be accepted as an idempotent migration"
+        );
+
+        disks[2]
+            .as_ref()
+            .expect("third target disk should be online")
+            .write_metadata("", bucket, object, free_version.clone())
+            .await
+            .expect("third equivalent target write should complete quorum");
+        assert!(
+            set_disks
+                .has_decommission_tier_free_version_write_quorum(bucket, object, &free_version, &opts)
+                .await
+                .expect("write-quorum target metadata should remain valid")
+        );
+    }
+
+    #[test]
+    fn decommission_tier_free_version_commit_rejects_lost_fence() {
+        let opts = ObjectOptions {
+            namespace_lock_fence: Some(NamespaceLockFence::lost_for_test()),
+            ..Default::default()
+        };
+
+        let err = ensure_decommission_tier_free_version_commit_fence("bucket", "object", &opts)
+            .expect_err("lost target lock must fail the free-version commit");
+        assert!(matches!(
+            err,
+            Error::NamespaceLockQuorumUnavailable {
+                mode: "decommission_tier_free_version_commit",
+                required: 1,
+                achieved: 0,
+                ..
+            }
+        ));
+    }
+
     #[test]
     fn test_resolve_tiered_decommission_write_quorum_result_allows_successful_quorum() {
         let errs = vec![None, None, Some(DiskError::DiskNotFound), None];