From 03875d61e3959c510f0d6b45282fcc72eb160db3 Mon Sep 17 00:00:00 2001
From: Feng Ruohang <rh@vonng.com>
Date: Sun, 25 Oct 2026 13:02:23 +0800
Subject: [PATCH] fix: reuse validated latest state without rescanning version
 history

Signed-off-by: Feng Ruohang <rh@vonng.com>
---
 cmd/erasure-object.go                   |  2 +-
 cmd/object-mutation-consistency_test.go |  2 +-
 cmd/object-mutation.go                  | 41 ++++++++-----------------
 3 files changed, 14 insertions(+), 31 deletions(-)

diff --git a/cmd/erasure-object.go b/cmd/erasure-object.go
index e9a2fbb8f..c2dbcfdcb 100644
--- a/cmd/erasure-object.go
+++ b/cmd/erasure-object.go
@@ -997,7 +997,7 @@ func (er erasureObjects) getObjectFileInfo(ctx context.Context, bucket, object s
 		rw.Lock()
 		// when its a versioned bucket and empty versionID - at totalResp == setDriveCount
 		// we must use rawFileInfo to resolve versions to figure out the latest version.
-		if opts.VersionID == "" && totalResp == er.setDriveCount && !uniformLatestVersion(rawArr, metaArr, errs) {
+		if opts.VersionID == "" && totalResp == er.setDriveCount && !uniformLatestVersion(metaArr, errs) {
 			fi, onlineMeta, onlineDisks, modTime, etag, err = calcQuorum(pickLatestQuorumFilesInfo(ctx,
 				rawArr, errs, bucket, object, readData, opts.InclFreeVersions))
 		} else {
diff --git a/cmd/object-mutation-consistency_test.go b/cmd/object-mutation-consistency_test.go
index 8573777ff..3c1c121cb 100644
--- a/cmd/object-mutation-consistency_test.go
+++ b/cmd/object-mutation-consistency_test.go
@@ -138,7 +138,7 @@ func TestMutationVersionHistoryRead(t *testing.T) {
 			}
 			meta[i], errs[i] = fileInfoFromRaw(raw[i], bucket, object, false, false)
 		}
-		return uniformLatestVersion(raw, meta, errs)
+		return uniformLatestVersion(meta, errs)
 	}
 	if !uniform() {
 		t.Fatal("healthy version history requires redundant full metadata decoding")
diff --git a/cmd/object-mutation.go b/cmd/object-mutation.go
index 8b1bdb2f0..be187d8be 100644
--- a/cmd/object-mutation.go
+++ b/cmd/object-mutation.go
@@ -194,37 +194,20 @@ func (s *xlStorage) undoWrite(ctx context.Context, volume, path string, fi FileI
 	return nil
 }
 
-// All drives have replied. A uniform indexed latest version may avoid the
-// second metadata decode, including healthy version histories. Conflicts retain
-// the full merge. Exact FileInfo comparison also prevents the four-byte header
-// signature from being treated as a collision-free identity.
-func uniformLatestVersion(raw []RawFileInfo, meta []FileInfo, errs []error) bool {
-	if len(raw) == 0 {
+// All drives have replied, and fileInfoFromRaw has already validated each raw
+// buffer and selected its latest visible version. Reuse that decoded state:
+// revalidating the raw history here adds work proportional to version count.
+// Any missing response, logical disagreement, or history-property disagreement
+// retains the full merge. Legacy objects and delete markers also use that path.
+func uniformLatestVersion(meta []FileInfo, errs []error) bool {
+	if len(meta) == 0 {
 		return false
 	}
-	var first xlMetaV2VersionHeader
-	var firstVersions int
-	for i, r := range raw {
-		if errs[i] != nil || !meta[i].IsValid() || !sameFileInfoVersion(meta[0], meta[i]) {
-			return false
-		}
-		buf, _, err := isIndexedMetaV2(r.Buf)
-		if err != nil || buf == nil {
-			return false
-		}
-		n, hv, mv, rest, err := decodeXLHeaders(buf)
-		if err != nil || n < 1 || mv != xlMetaVersion {
-			return false
-		}
-		var h xlMetaV2VersionHeader
-		err = decodeVersions(rest, 1, func(_ int, hdr, _ []byte) error { _, e := h.unmarshalV(hv, hdr); return e })
-		if err != nil || h.Type != ObjectType || h.FreeVersion() {
-			return false
-		}
-		if i == 0 {
-			first = h
-			firstVersions = n
-		} else if h != first || n != firstVersions || meta[i].NumVersions != meta[0].NumVersions || !meta[i].SuccessorModTime.Equal(meta[0].SuccessorModTime) {
+	first := meta[0]
+	for i, fi := range meta {
+		if errs[i] != nil || !fi.IsValid() || fi.XLV1 || fi.Deleted || !fi.IsLatest || fi.NumVersions < 1 ||
+			!fi.ModTime.Equal(first.ModTime) || !sameFileInfoVersion(first, fi) ||
+			fi.NumVersions != first.NumVersions || !fi.SuccessorModTime.Equal(first.SuccessorModTime) {
 			return false
 		}
 	}