From 9c8678ded97dac7359349b553c15386db7d626ca Mon Sep 17 00:00:00 2001
From: chrislu <chris.lu@gmail.com>
Date: Thu, 13 Oct 2022 23:15:00 -0700
Subject: [PATCH] ensure monotonic n.AppendAtNs

fix https://github.com/seaweedfs/seaweedfs/issues/3852
---
 weed/storage/volume_write.go | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/weed/storage/volume_write.go b/weed/storage/volume_write.go
index 223e19577..2dc813216 100644
--- a/weed/storage/volume_write.go
+++ b/weed/storage/volume_write.go
@@ -157,7 +157,7 @@ func (v *Volume) doWriteRequest(n *needle.Needle, checkCookie bool) (offset uint
 	}
 
 	// append to dat file
-	n.AppendAtNs = uint64(time.Now().UnixNano())
+	n.AppendAtNs = max(uint64(time.Now().UnixNano()), v.lastAppendAtNs+1)
 	offset, size, _, err = n.Append(v.DataBackend, v.Version())
 	v.checkReadWriteError(err)
 	if err != nil {
@@ -330,3 +330,10 @@ func (v *Volume) WriteNeedleBlob(needleId NeedleId, needleBlob []byte, size Size
 
 	return err
 }
+
+func max(x, y uint64) uint64 {
+	if x <= y {
+		return y
+	}
+	return x
+}