wal: lock WAL file while repairing

wal/repair.go

@@ -76,7 +76,7 @@ func Repair(dirpath string) bool {
 				plog.Errorf("could not repair %v, failed to truncate file", f.Name())
 				return false
 			}
-			if err = fileutil.Fsync(f); err != nil {
+			if err = fileutil.Fsync(f.File); err != nil {
 				plog.Errorf("could not repair %v, failed to sync file", f.Name())
 				return false
 			}
@@ -89,7 +89,7 @@ func Repair(dirpath string) bool {
 }
 
 // openLast opens the last wal file for read and write.
-func openLast(dirpath string) (*os.File, error) {
+func openLast(dirpath string) (*fileutil.LockedFile, error) {
 	names, err := fileutil.ReadDir(dirpath)
 	if err != nil {
 		return nil, err
@@ -99,5 +99,5 @@ func openLast(dirpath string) (*os.File, error) {
 		return nil, ErrFileNotFound
 	}
 	last := path.Join(dirpath, names[len(names)-1])
-	return os.OpenFile(last, os.O_RDWR, 0)
+	return fileutil.LockFile(last, os.O_RDWR, 0600)
 }

wal/repair_test.go

@@ -34,10 +34,8 @@ func TestRepairTruncate(t *testing.T) {
 		if err != nil {
 			return err
 		}
-		if terr := f.Truncate(offset - 4); terr != nil {
-			return terr
-		}
-		return nil
+		defer f.Close()
+		return f.Truncate(offset - 4)
 	}
 
 	testRepair(t, makeEnts(10), corruptf, 9)
@@ -140,6 +138,7 @@ func TestRepairWriteTearLast(t *testing.T) {
 		if err != nil {
 			return err
 		}
+		defer f.Close()
 		// 512 bytes perfectly aligns the last record, so use 1024
 		if offset < 1024 {
 			return fmt.Errorf("got offset %d, expected >1024", offset)
@@ -163,6 +162,7 @@ func TestRepairWriteTearMiddle(t *testing.T) {
 		if err != nil {
 			return err
 		}
+		defer f.Close()
 		// corrupt middle of 2nd record
 		_, werr := f.WriteAt(make([]byte, 512), 4096+512)
 		return werr