Log Rotater: Fix data race

We were accessing the file using stat and trimming + replacing the file
handler possibly at the same time. Just put a mutex over everything to protect it better.

This was caught using Go's race detector

1 files changed, 2 insertions, 2 deletions

diff --git a/internal/log/rotate.go b/internal/log/rotate.go
index 27907ce..2971f70 100644
--- a/internal/log/rotate.go
+++ b/internal/log/rotate.go
@@ -50,8 +50,6 @@ func (fr *FileRotater) open() error {
 }
 
 func (fr *FileRotater) trim() error {
-	fr.mu.Lock()
-	defer fr.mu.Unlock()
 	// We need to seek to the trim size to skip over that part as we discard it
 	_, err := fr.file.Seek(TrimSize, io.SeekStart)
 	if err != nil {
@@ -85,6 +83,8 @@ func (fr *FileRotater) trim() error {
 
 // Write implements io.Writer for the log rotater
 func (fr *FileRotater) Write(p []byte) (n int, err error) {
+	fr.mu.Lock()
+	defer fr.mu.Unlock()
 	fi, err := fr.file.Stat()
 	if err != nil {
 		return 0, err