From b5cdd7160043b8bac77731a5c756a0f5a0381a34 Mon Sep 17 00:00:00 2001
From: Chris Lu <chris.lu@gmail.com>
Date: Thu, 2 Apr 2026 12:18:56 -0700
Subject: [PATCH] filer.sync: include last error in stall diagnostics

---
 weed/command/filer_sync.go                     | 9 +++++++--
 weed/replication/sink/filersink/fetch_write.go | 1 +
 weed/replication/sink/filersink/filer_sink.go  | 1 +
 3 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/weed/command/filer_sync.go b/weed/command/filer_sync.go
index 7b9c85c99..a509deb48 100644
--- a/weed/command/filer_sync.go
+++ b/weed/command/filer_sync.go
@@ -375,8 +375,13 @@ func doSubscribeFilerMetaChanges(clientId int32, clientEpoch int32, sourceGrpcDi
 		lastLogTsNs = now
 		if offsetTsNs == lastProgressedTsNs {
 			for _, t := range filerSink.ActiveTransfers() {
-				glog.V(0).Infof("  %s %s: %d bytes received, %s",
-					t.ChunkFileId, t.Path, t.BytesReceived, t.Status)
+				if t.LastErr != "" {
+					glog.V(0).Infof("  %s %s: %d bytes received, %s, last error: %s",
+						t.ChunkFileId, t.Path, t.BytesReceived, t.Status, t.LastErr)
+				} else {
+					glog.V(0).Infof("  %s %s: %d bytes received, %s",
+						t.ChunkFileId, t.Path, t.BytesReceived, t.Status)
+				}
 			}
 		}
 		lastProgressedTsNs = offsetTsNs
diff --git a/weed/replication/sink/filersink/fetch_write.go b/weed/replication/sink/filersink/fetch_write.go
index 35ce29501..d711b76d3 100644
--- a/weed/replication/sink/filersink/fetch_write.go
+++ b/weed/replication/sink/filersink/fetch_write.go
@@ -335,6 +335,7 @@ func (fs *FilerSink) fetchAndWrite(sourceChunk *filer_pb.FileChunk, path string,
 			glog.V(1).Infof("skip retrying stale source %s for %s: %v", sourceChunk.GetFileIdString(), path, retryErr)
 			return false
 		}
+		transferStatus.LastErr = retryErr.Error()
 		if isEofError(retryErr) {
 			eofBackoff = nextEofBackoff(eofBackoff)
 			transferStatus.BytesReceived = int64(len(partialData))
diff --git a/weed/replication/sink/filersink/filer_sink.go b/weed/replication/sink/filersink/filer_sink.go
index b42c89fab..6bdeb10ee 100644
--- a/weed/replication/sink/filersink/filer_sink.go
+++ b/weed/replication/sink/filersink/filer_sink.go
@@ -27,6 +27,7 @@ type ChunkTransferStatus struct {
 	Path          string
 	BytesReceived int64
 	Status        string // "downloading", "uploading", or "waiting 10s" etc.
+	LastErr       string
 }
 
 type FilerSink struct {