From 3daaefec606d95926511f9f3bfcbca097957cc6b Mon Sep 17 00:00:00 2001
From: chrislu <chris.lu@gmail.com>
Date: Sun, 25 Dec 2022 12:12:22 -0800
Subject: [PATCH] add debug mode to compare data read and write

---
 weed/mount/filehandle.go        | 17 ++++++++++++++++-
 weed/mount/weedfs_file_read.go  | 19 +++++++++++++++++++
 weed/mount/weedfs_file_sync.go  |  4 ++++
 weed/mount/weedfs_file_write.go |  5 +++++
 4 files changed, 44 insertions(+), 1 deletion(-)

diff --git a/weed/mount/filehandle.go b/weed/mount/filehandle.go
index 1dd70e861..a08b66a00 100644
--- a/weed/mount/filehandle.go
+++ b/weed/mount/filehandle.go
@@ -5,14 +5,16 @@ import (
 	"github.com/seaweedfs/seaweedfs/weed/glog"
 	"github.com/seaweedfs/seaweedfs/weed/pb/filer_pb"
 	"github.com/seaweedfs/seaweedfs/weed/util"
-	"golang.org/x/exp/slices"
 	"golang.org/x/sync/semaphore"
 	"math"
+	"os"
 	"sync"
 )
 
 type FileHandleId uint64
 
+var IsDebug = true
+
 type FileHandle struct {
 	fh        FileHandleId
 	counter   int64
@@ -31,6 +33,9 @@ type FileHandle struct {
 	orderedMutex   *semaphore.Weighted
 
 	isDeleted bool
+
+	// for debugging
+	mirrorFile *os.File
 }
 
 func newFileHandle(wfs *WFS, handleId FileHandleId, inode uint64, entry *filer_pb.Entry) *FileHandle {
@@ -50,6 +55,14 @@ func newFileHandle(wfs *WFS, handleId FileHandleId, inode uint64, entry *filer_p
 		Entry: entry,
 	}
 
+	if IsDebug {
+		var err error
+		fh.mirrorFile, err = os.OpenFile("/tmp/sw/"+entry.Name, os.O_RDWR|os.O_CREATE, 0600)
+		if err != nil {
+			println("failed to create mirror:", err.Error())
+		}
+	}
+
 	return fh
 }
 
@@ -97,5 +110,7 @@ func (fh *FileHandle) Release() {
 
 	fh.dirtyPages.Destroy()
 	fh.CloseReader()
+	if IsDebug {
+		fh.mirrorFile.Close()
 	}
 }
diff --git a/weed/mount/weedfs_file_read.go b/weed/mount/weedfs_file_read.go
index a5a17a3ba..d098b6883 100644
--- a/weed/mount/weedfs_file_read.go
+++ b/weed/mount/weedfs_file_read.go
@@ -1,7 +1,9 @@
 package mount
 
 import (
+	"bytes"
 	"context"
+	"fmt"
 	"io"
 
 	"github.com/hanwen/go-fuse/v2/fuse"
@@ -50,6 +52,23 @@ func (wfs *WFS) Read(cancel <-chan struct{}, in *fuse.ReadIn, buff []byte) (fuse
 		return nil, fuse.EIO
 	}
 
+	if IsDebug {
+		// print(".")
+		mirrorData := make([]byte, totalRead)
+		fh.mirrorFile.ReadAt(mirrorData, offset)
+		if bytes.Compare(mirrorData, buff[:totalRead]) != 0 {
+
+			againBuff := make([]byte, len(buff))
+			againRead, _ := readDataByFileHandle(buff, fh, offset)
+			againCorrect := bytes.Compare(mirrorData, againBuff[:againRead]) == 0
+			againSame := bytes.Compare(buff[:totalRead], againBuff[:againRead]) == 0
+
+			fmt.Printf("\ncompare %v [%d,%d) size:%d againSame:%v againCorrect:%v\n", fh.mirrorFile.Name(), offset, offset+totalRead, totalRead, againSame, againCorrect)
+			//fmt.Printf("read mirrow data: %v\n", mirrorData)
+			//fmt.Printf("read actual data: %v\n", buff[:totalRead])
+		}
+	}
+
 	return fuse.ReadResultData(buff[:totalRead]), fuse.OK
 }
 
diff --git a/weed/mount/weedfs_file_sync.go b/weed/mount/weedfs_file_sync.go
index 429924592..2022f88a6 100644
--- a/weed/mount/weedfs_file_sync.go
+++ b/weed/mount/weedfs_file_sync.go
@@ -181,5 +181,9 @@ func (wfs *WFS) doFlush(fh *FileHandle, uid, gid uint32) fuse.Status {
 		return fuse.EIO
 	}
 
+	if IsDebug {
+		fh.mirrorFile.Sync()
+	}
+
 	return fuse.OK
 }
diff --git a/weed/mount/weedfs_file_write.go b/weed/mount/weedfs_file_write.go
index 3eaefef94..5e2e14f25 100644
--- a/weed/mount/weedfs_file_write.go
+++ b/weed/mount/weedfs_file_write.go
@@ -73,5 +73,10 @@ func (wfs *WFS) Write(cancel <-chan struct{}, in *fuse.WriteIn, data []byte) (wr
 
 	fh.dirtyMetadata = true
 
+	if IsDebug {
+		// print("+")
+		fh.mirrorFile.WriteAt(data, offset)
+	}
+
 	return written, fuse.OK
 }