Added error wrapping to more funcs in ftp

backend/ftp/dataconn.go

@@ -144,23 +144,23 @@ func getDataConn(ctx context.Context, authority utils.Authority, fs *FileSystem,
 	if fs.dataconn != nil && fs.dataconn.Mode() != t {
 		// wrong session type ... close current session and unset it (ps so we can set a new one after)
 		if err := fs.dataconn.Close(); err != nil {
-			return nil, wrapGetDataConnError(err)
+			return nil, wrapGetDataConnError(fmt.Errorf("dataconn.Close error: %w", err))
 		}
 		fs.dataconn = nil
 	}
 
 	if fs.dataconn == nil || fs.resetConn {
 		client, err := fs.Client(ctx, authority)
 		if err != nil {
-			return nil, wrapGetDataConnError(err)
+			return nil, wrapGetDataConnError(fmt.Errorf("fs.Client error: %w", err))
 		}
 
 		switch t {
 		case types.OpenRead:
 			resp, err := client.RetrFrom(f.Path(), uint64(f.offset))
 			// check errors
 			if err != nil {
-				return nil, wrapGetDataConnError(err)
+				return nil, wrapGetDataConnError(fmt.Errorf("client.RetrFrom error: %w", err))
 			}
 			fs.dataconn = &dataConn{
 				R:    resp,

backend/ftp/fileSystem.go

@@ -109,7 +109,7 @@ func (fs *FileSystem) Client(ctx context.Context, authority utils.Authority) (ty
 			var err error
 			fs.ftpclient, err = defaultClientGetter(ctx, authority, opts)
 			if err != nil {
-				return nil, err
+				return nil, fmt.Errorf("cannot get client: %w", err)
 			}
 		} else {
 			return nil, fmt.Errorf("unable to create client, vfs.Options must be an ftp.Options")

backend/ftp/options.go

@@ -46,13 +46,13 @@ func getClient(ctx context.Context, authority utils.Authority, opts Options) (ty
 	// dial connection
 	c, err := _ftp.Dial(fetchHostPortString(authority), fetchDialOptions(ctx, authority, opts)...)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to dial connection: %w", err)
 	}
 
 	// login
 	err = c.Login(fetchUsername(authority), fetchPassword(opts))
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to login: %w", err)
 	}
 
 	return c, nil