关于读取BFILE到BLOB的问题，这段程序怎么会报错

[愤怒对抗喳喳]

declare
f_lob bfile;
b_lob blob;
begin
insert into blob_demo values (1,empty_blob())
return image into b_lob;
f_lob := bfilename( 'c:\','153989.jpg');
dbms_lob.fileopen(f_lob, dbms_lob.file_readonly);
dbms_lob.loadfromfile( b_lob, f_lob, dbms_lob.getlength(f_lob) );
dbms_lob.fileclose(f_lob);
commit;
end;

肯定目录绝对存在而且在服务器端
错误为
ORA-22285: non-existent directory or file for FILEOPEN operation
ORA-06512: at "SYS.DBMS_LOB", line 475
ORA-06512: at "VIRTUOSO.INSERT_IMG", line 7
ORA-06512: at line 1

[愤怒对抗喳喳]

咋没人回答