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fix(storage): 修复 WAL.Clear() nil panic 并添加并发安全保护 #31

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Merged
NeverENG merged 1 commit into from
May 11, 2026
Merged

fix(storage): 修复 WAL.Clear() nil panic 并添加并发安全保护 #31

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13 changes: 9 additions & 4 deletions Raft/raft_wal.go
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Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,7 @@ import (
"encoding/binary"
"errors"
"fmt"
"io"
"os"
"path/filepath"
"strconv"
Expand Down Expand Up @@ -167,7 +168,7 @@ func (w *RaftWAL) LoadLogs() ([]LogEntry, error) {
break
}
cmd := make([]byte, cmdLen)
if _, err := f.Read(cmd); err != nil {
if _, err := io.ReadFull(f, cmd); err != nil {
break
}

Expand All @@ -182,11 +183,15 @@ func (w *RaftWAL) LoadLogs() ([]LogEntry, error) {
}

func (w *RaftWAL) Clear() error {
w.Close()
if err := os.Remove(w.logPath); err != nil {
if err := w.Close(); err != nil {
return err
}
w.file = nil

if err := os.Remove(w.logPath); err != nil && !os.IsNotExist(err) {
return err
}
if err := os.Remove(w.metaPath); err != nil {
if err := os.Remove(w.metaPath); err != nil && !os.IsNotExist(err) {
return err
}

Expand Down
93 changes: 57 additions & 36 deletions storage/zstorage/WAL.go
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Original file line number Diff line number Diff line change
Expand Up @@ -7,34 +7,36 @@ import (
"io"
"log/slog"
"os"
"sync"

"github.com/NeverENG/BanDB/config"
"github.com/NeverENG/BanDB/storage/istorage"
)

const HEADER_LENGTH = 12
const headerLength = 12

var _ istorage.IWal = &WAL{}

type WAL struct {
mu sync.Mutex
file *os.File
headerBuf [HEADER_LENGTH]byte
headerBuf [headerLength]byte
}

func NewWAL() *WAL {
file, err := os.OpenFile(config.G.WALPath, os.O_APPEND|os.O_RDWR|os.O_CREATE, 0644)
if err != nil {
slog.Error("[ERROR]:OPEN WAL LOG ERROR !", "path", config.G.WALPath, "error", err)
slog.Warn("[WARN]:WAL DISABLED, DATA WILL NOT BE PERSISTED")
// 返回一个空的WAL，不报错
slog.Warn("cannot open WAL, running in disabled mode", "path", config.G.WALPath, "error", err)
return &WAL{file: nil}
}
slog.Info("[INFO]:WAL OPENED SUCCESSFULLY", "path", config.G.WALPath)
slog.Info("WAL opened", "path", config.G.WALPath)
return &WAL{file: file}
}

func (w *WAL) Write(entry istorage.LogEntry) error {
// 如果 file is nil，跳过写入（WAL 禁用模式
w.mu.Lock()
defer w.mu.Unlock()

if w.file == nil {
return nil
}
Expand All @@ -48,28 +50,26 @@ func (w *WAL) Write(entry istorage.LogEntry) error {
binary.BigEndian.PutUint32(w.headerBuf[4:], uint32(len(entry.Key)))
binary.BigEndian.PutUint32(w.headerBuf[8:], uint32(len(entry.Value)))

_, err := w.file.Write(w.headerBuf[:])
if err != nil {
slog.Error("[ERROR]:WRITE WAL LOG ERROR !")
if _, err := w.file.Write(w.headerBuf[:]); err != nil {
slog.Error("write WAL header failed", "error", err)
return err
}

_, err = w.file.Write(entry.Key)
if err != nil {
slog.Error("[ERROR]:WRITE WAL LOG ERROR !")
if _, err := w.file.Write(entry.Key); err != nil {
slog.Error("write WAL key failed", "error", err)
return err
}
_, err = w.file.Write(entry.Value)
if err != nil {
slog.Error("[ERROR]:WRITE WAL LOG ERROR !")
if _, err := w.file.Write(entry.Value); err != nil {
slog.Error("write WAL value failed", "error", err)
return err
}

return w.Sync()
return w.file.Sync()
}

func (w *WAL) Read() ([]istorage.LogEntry, error) {
// 如果 file is nil，跳过读
w.mu.Lock()
defer w.mu.Unlock()

if w.file == nil {
return nil, nil
}
Expand All @@ -81,10 +81,10 @@ func (w *WAL) Read() ([]istorage.LogEntry, error) {
entries := make([]istorage.LogEntry, 0)

for {
header := make([]byte, HEADER_LENGTH)
_, err := w.file.Read(header)
header := make([]byte, headerLength)
_, err := io.ReadFull(w.file, header)
if err != nil {
if errors.Is(err, io.EOF) || errors.Is(err, os.ErrClosed) {
if errors.Is(err, io.EOF) || errors.Is(err, io.ErrUnexpectedEOF) || errors.Is(err, os.ErrClosed) {
break
}
return entries, err
Expand All @@ -95,18 +95,16 @@ func (w *WAL) Read() ([]istorage.LogEntry, error) {
valueLen := binary.BigEndian.Uint32(header[8:])

key := make([]byte, keyLen)
_, err = w.file.Read(key)
if err != nil {
if errors.Is(err, io.EOF) {
if _, err := io.ReadFull(w.file, key); err != nil {
if errors.Is(err, io.EOF) || errors.Is(err, io.ErrUnexpectedEOF) {
break
}
return entries, err
}

value := make([]byte, valueLen)
_, err = w.file.Read(value)
if err != nil {
if errors.Is(err, io.EOF) {
if _, err := io.ReadFull(w.file, value); err != nil {
if errors.Is(err, io.EOF) || errors.Is(err, io.ErrUnexpectedEOF) {
break
}
return entries, err
Expand All @@ -116,7 +114,7 @@ func (w *WAL) Read() ([]istorage.LogEntry, error) {
hasher.Write(key)
hasher.Write(value)
if crc != hasher.Sum32() {
slog.Error("[ERROR]:THE DATA ERROR !")
slog.Error("WAL data corruption detected")
return entries, errors.New("data corruption detected")
}

Expand All @@ -127,35 +125,58 @@ func (w *WAL) Read() ([]istorage.LogEntry, error) {
}

func (w *WAL) Close() error {
w.mu.Lock()
defer w.mu.Unlock()

if w.file == nil {
return nil
}
return w.file.Close()
}

func (w *WAL) Sync() error {
w.mu.Lock()
defer w.mu.Unlock()

if w.file == nil {
return nil
}
return w.file.Sync()
}

// 采用日志滚动的模式来启动 Clear
func (w *WAL) Clear() error {
w.mu.Lock()
defer w.mu.Unlock()

if w.file == nil {
// WAL disabled mode: try to remove old file by path, then reopen
if err := os.Remove(config.G.WALPath); err != nil && !os.IsNotExist(err) {
return err
}
f, err := os.OpenFile(config.G.WALPath, os.O_APPEND|os.O_RDWR|os.O_CREATE, 0644)
if err != nil {
slog.Warn("WAL disabled, cannot reopen after clear", "error", err)
return nil
}
w.file = f
return nil
}

if err := w.Close(); err != nil {
slog.Error("[ERROR]:CLOSE WAL LOG ERROR !")
path := w.file.Name()
if err := w.file.Close(); err != nil {
slog.Error("close WAL before clear failed", "error", err)
return err
}

if err := os.Remove(w.file.Name()); err != nil {
if err := os.Remove(path); err != nil && !os.IsNotExist(err) {
return err
}

f, err := os.OpenFile(w.file.Name(), os.O_APPEND|os.O_RDWR|os.O_CREATE, 0644)
f, err := os.OpenFile(path, os.O_APPEND|os.O_RDWR|os.O_CREATE, 0644)
if err != nil {
slog.Error("[ERROR]:OPEN WAL LOG ERROR !")
slog.Error("reopen WAL after clear failed", "error", err)
return err
}
w.file = f
return w.Sync()
return w.file.Sync()
}
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