about: fix potential overflow of about in various backends

Before this fix it was possible for an about call in various backends
to exceed an int64 and wrap.

This patch causes it to clip to the max int64 value instead.

Author: ncw

backend/dropbox/dropbox.go

@@ -1446,9 +1446,9 @@ func (f *Fs) About(ctx context.Context) (usage *fs.Usage, err error) {
 		}
 	}
 	usage = &fs.Usage{
-		Total: fs.NewUsageValue(int64(total)),        // quota of bytes that can be used
-		Used:  fs.NewUsageValue(int64(used)),         // bytes in use
-		Free:  fs.NewUsageValue(int64(total - used)), // bytes which can be uploaded before reaching the quota
+		Total: fs.NewUsageValue(total),        // quota of bytes that can be used
+		Used:  fs.NewUsageValue(used),         // bytes in use
+		Free:  fs.NewUsageValue(total - used), // bytes which can be uploaded before reaching the quota
 	}
 	return usage, nil
 }

backend/hdfs/fs.go

@@ -371,9 +371,9 @@ func (f *Fs) About(ctx context.Context) (*fs.Usage, error) {
 		return nil, err
 	}
 	return &fs.Usage{
-		Total: fs.NewUsageValue(int64(info.Capacity)),
-		Used:  fs.NewUsageValue(int64(info.Used)),
-		Free:  fs.NewUsageValue(int64(info.Remaining)),
+		Total: fs.NewUsageValue(info.Capacity),
+		Used:  fs.NewUsageValue(info.Used),
+		Free:  fs.NewUsageValue(info.Remaining),
 	}, nil
 }
 

backend/mega/mega.go

@@ -946,9 +946,9 @@ func (f *Fs) About(ctx context.Context) (*fs.Usage, error) {
 		return nil, fmt.Errorf("failed to get Mega Quota: %w", err)
 	}
 	usage := &fs.Usage{
-		Total: fs.NewUsageValue(int64(q.Mstrg)),           // quota of bytes that can be used
-		Used:  fs.NewUsageValue(int64(q.Cstrg)),           // bytes in use
-		Free:  fs.NewUsageValue(int64(q.Mstrg - q.Cstrg)), // bytes which can be uploaded before reaching the quota
+		Total: fs.NewUsageValue(q.Mstrg),           // quota of bytes that can be used
+		Used:  fs.NewUsageValue(q.Cstrg),           // bytes in use
+		Free:  fs.NewUsageValue(q.Mstrg - q.Cstrg), // bytes which can be uploaded before reaching the quota
 	}
 	return usage, nil
 }

backend/premiumizeme/premiumizeme.go

@@ -793,7 +793,7 @@ func (f *Fs) About(ctx context.Context) (usage *fs.Usage, err error) {
 		return nil, err
 	}
 	usage = &fs.Usage{
-		Used: fs.NewUsageValue(int64(info.SpaceUsed)),
+		Used: fs.NewUsageValue(info.SpaceUsed),
 	}
 	return usage, nil
 }

backend/sftp/sftp.go

@@ -1863,9 +1863,9 @@ func (f *Fs) About(ctx context.Context) (*fs.Usage, error) {
 		free := vfsStats.FreeSpace()
 		used := total - free
 		return &fs.Usage{
-			Total: fs.NewUsageValue(int64(total)),
-			Used:  fs.NewUsageValue(int64(used)),
-			Free:  fs.NewUsageValue(int64(free)),
+			Total: fs.NewUsageValue(total),
+			Used:  fs.NewUsageValue(used),
+			Free:  fs.NewUsageValue(free),
 		}, nil
 	} else if err != nil {
 		if errors.Is(err, os.ErrNotExist) {

backend/smb/smb.go

@@ -494,11 +494,11 @@ func (f *Fs) About(ctx context.Context) (_ *fs.Usage, err error) {
 		return nil, err
 	}
 
-	bs := int64(stat.BlockSize())
+	bs := stat.BlockSize()
 	usage := &fs.Usage{
-		Total: fs.NewUsageValue(bs * int64(stat.TotalBlockCount())),
-		Used:  fs.NewUsageValue(bs * int64(stat.TotalBlockCount()-stat.FreeBlockCount())),
-		Free:  fs.NewUsageValue(bs * int64(stat.AvailableBlockCount())),
+		Total: fs.NewUsageValue(bs * stat.TotalBlockCount()),
+		Used:  fs.NewUsageValue(bs * (stat.TotalBlockCount() - stat.FreeBlockCount())),
+		Free:  fs.NewUsageValue(bs * stat.AvailableBlockCount()),
 	}
 	return usage, nil
 }