mmap on jffs2

Sun Apr 20 10:00:51 EDT 2003

I am using jffs2 on a ppc860 system(amd29lv160).
Things seems ok,but when I am trying mmap.
I want to mmap a file in flash,so i can treat
the file like some records.
I mean operation like
 fd = open("/usr/dat/sot.dat",O_RDWR,FILEMODE);

 ptr1=mmap(NULL,filesize,PROT_READ|PROT_WRITE,
 MAP_SHARED,fd,0);
fd returns 3 and it is ok,however ptr1 returns -1.
I checked the errno it said invalid argument.
I have to say arguments "filesize" above is not
aligment to any requirements,just the real file
size?Does it matter?
The same procedure can done on common ext2
so i wonder jffs2 implement all the features like
ext2?
leeyang