Re: DD-ing from device to device.

[R.E.Wolff@BitWizard.nl (Rogier Wolff)]

Andreas Dilger wrote:
> On Nov 19, 2001  18:28 +0100, Rogier Wolff wrote:
> > > There is another report saying 2.4.14
> > > also "Creating partitions under 2.4.14", and I have read several more
> > > recently but am unsure of the exact kernel version.  What fs are you
> > > using, just in case it matters?
> > 
> > ext2. 
> 
> Well, I just tried this on ext2 instead of ext3 (on my 2.4.13 system)
> and it worked fine as a logged-in non-root user (creates a 16GB sparse file):
> 
> dd if=/dev/zero of=tt bs=1k count=1 seek=16M


 /tmp> dd if=/dev/zero of=tt bs=1k count=1 seek=16M
dd: tt: Invalid argument
1+0 records in
1+0 records out
 /tmp> dd if=/dev/zero of=tt bs=1k seek=2047k
19913+0 records in
19912+0 records out
^C
 /tmp> ls -al tt
ls: tt: Value too large for defined data type
 /tmp> su
Password: 
 /tmp# rm tt
rm: cannot remove `tt': Value too large for defined data type
 /tmp# mv tt xx
mv: tt: Value too large for defined data type
 /tmp# rm -f tt
rm: cannot remove `tt': Value too large for defined data type
 /tmp# dd if=/dev/zero of=uu bs=1k count=2050 seek=2047k
2050+0 records in
2050+0 records out
 /tmp# l uu
ls: uu: Value too large for defined data type
 /tmp# 

> Can you test the "dd" above to ensure it works with your tools and the old
> kernel?  For your next 2.4.14 kernel build, it may be instructive to put
> a printk() inside the 3 checks in generic_file_write() before it outputs
> SIGXFSZ, which tells us limit and RLIM_INIFINITY, pos and count, and pos
> and s_maxbytes are, respectively.  This will also tell us what limit is
> being hit (although it is most likely a ulimit issue).

Grmbl...  I'll see what I can do. 

		Rogier. 

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