tiering: fix inverted test

storage.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"io"
 	"log"
+	"math/rand"
 	"os"
 	"path/filepath"
 	"time"
@@ -155,20 +156,39 @@ func (ts *tieredStorage) migrateNow() error {
 		return fmt.Errorf("Reading hot storage files: %w", err)
 	}
 
+	if len(dirents) == 0 {
+		return nil // Directory empty, nothing to do
+	}
+
 	cutOff := time.Now().Add(-TierMigrationAfter)
 
+	// Shuffle files to avoid getting stuck
+	rand.Shuffle(len(dirents), func(i, j int) {
+		dirents[i], dirents[j] = dirents[j], dirents[i]
+	})
+
+	log.Printf("tier-migration: Scanning %d items...", len(dirents))
+
+	var countMigrated int64 = 0
+
 	for _, dirent := range dirents {
 		fi, err := dirent.Info()
 		if err != nil {
 			return fmt.Errorf("Reading hot storage files: %w", err) // local files can't be stat'd = important error
 		}
 
-		if !fi.ModTime().After(cutOff) {
+		if fi.IsDir() {
+			continue // probably . or ..
+		}
+
+		if fi.ModTime().After(cutOff) {
 			continue // not eligible
 		}
 
 		fileHash := dirent.Name()
 
+		log.Printf("tier-migration: Migrating %q...", fileHash)
+
 		// Copy to cold storage
 		// Any concurrent reads will be serviced from the hot storage, so this
 		// is a safe operation
@@ -188,9 +208,13 @@ func (ts *tieredStorage) migrateNow() error {
 		if err != nil {
 			return fmt.Errorf("Remove %q from hot storage: %w", err) // can't rm local file
 		}
+
+		countMigrated++
 	}
 
 	// Migrated everything we can for now
+	log.Printf("tier-migration: Sleeping (migrated %d/%d items)", countMigrated, len(dirents))
+
 	return nil
 }