Re: CRC errors when continuous fseek/fputs on JFFS2

* Re: CRC errors when continuous fseek/fputs on JFFS2
       [not found] <20060516061354.GA18958@wohnheim.fh-wedel.de>
@ 2006-05-16 12:40 ` syed khader
  2006-05-16 14:26   ` Jörn Engel
  0 siblings, 1 reply; 12+ messages in thread
From: syed khader @ 2006-05-16 12:40 UTC (permalink / raw)
  To: linux-mtd

Hi 
  when I removed fseek/fwrite in the test case I am
not seeing any CRC errors. The modified code goes like
this :

int main()
{
   int fd;
   int i;
   char buf[SIZE];

   strcpy(buf, "abcdefg\r\n");
   printf("%s", buf);
   fd = open("testfile",O_RDWR|O_CREAT);
   for(i =0 ; i < 10 ; i++)
   {
      write(fd, buf, sizeof(buf));
      lseek(fd, -4, SEEK_CUR);
  }
}
   Why does CRC errors occur when I use fseek/fwrite
and not when I use plain system calls write/lseek??

Regards
Syed

--- Jï¿½rn Engel <joern@wohnheim.fh-wedel.de> wrote:

> On Mon, 15 May 2006 21:58:47 -0700, syed khader
> wrote:
> > 
> >   My question is not how the test case  should be
> > written, why would CRC errors appear when I never
> > powered off my system while it is writing into
> jffs2.
> >   I would like to ask what would happen if a
> integer
> > overflow occurs: does it result in crc error?
> 
> Anything resulting in a crc error is a bug.  But I
> cannot tell you
> much more with your current testcase.  fwrite() is
> implemented by the
> libc and does buffering.  Therefore it is impossible
> to tell when libc
> actually calls the kernel and which functions it
> calls with which
> parameters.  And that makes debugging fairly hard.
> 
> So a temporary question is indeed how the testcase
> should be written.
> Please replace the f* functions so we can remove
> libc from the
> picture.
> 
> Jï¿½rn
> 
> -- 
> Invincibility is in oneself, vulnerability is in the
> opponent.
> -- Sun Tzu
> 

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