Display message on failure to get lock on format.json in fs mode on startup (#6538)

Retry to see if the lock is free. Retry time will increase binomially.

cmd/format-fs.go

@@ -24,6 +24,7 @@ import (
 	"path"
 	"time"
 
+	"github.com/minio/minio/cmd/logger"
 	"github.com/minio/minio/pkg/lock"
 )
 
@@ -332,11 +333,24 @@ func formatFSFixDeploymentID(fsFormatPath string) error {
 		return nil
 	}
 
+	formatStartTime := time.Now().Round(time.Second)
+	getElapsedTime := func() string {
+		return time.Now().Round(time.Second).Sub(formatStartTime).String()
+	}
+
+	doneCh := make(chan struct{})
+	defer close(doneCh)
+
+	retryTimerCh := newRetryTimerSimple(doneCh)
 	for {
+		select {
+		case <-retryTimerCh:
+
 			wlk, err := lock.TryLockedOpenFile(fsFormatPath, os.O_RDWR, 0)
 			if err == lock.ErrAlreadyLocked {
-			// Lock already present, sleep and attempt again.
+				// Lock already present, sleep and attempt again
-			time.Sleep(100 * time.Millisecond)
+
+				logger.Info("Another minio process(es) might be holding a lock to the file %s. Please kill that minio process(es) (elapsed %s)\n", fsFormatPath, getElapsedTime())
 				continue
 			}
 			if err != nil {
@@ -356,5 +370,6 @@ func formatFSFixDeploymentID(fsFormatPath string) error {
 			format.ID = mustGetUUID()
 			return jsonSave(wlk, format)
 		}
+	}
 
 }