why raw devices don't seek above 4GB (sometimes)

why raw devices don't seek above 4GB (sometimes)

[k.lichtenwalder]

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ok,
I found my problem. As previously said, I'm on reiser. Which (obviously)
has a file size limit of 4GB set in the superblock. Llseek only allows
seek offsets which are smaller than the allowed file size. What happens
is:
I set up a raw device: raw /dev/raw/raw1 /dev/hdd
with /dev/hdd being my DVD drive.
Xine then does repeated llseeks on /dev/raw/raw1 until it gets above 4G.
Because /dev/raw/raw1 and the associated /dev/hdd both are on reiserfs,
and reiserfs has a 4G limit, llseek assumes the same for the associated
raw devices and returns from the llseek with EINVAL. Bang. 
I don't know whether there's an easy solution. 
Please contact me if you nee further details/tests

Klaus
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 Klaus Lichtenwalder, Dipl. Inform.,       http://www.webforum.de/Klaus/
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Re: why raw devices don't seek above 4GB (sometimes)

[Alan Cox]

> I set up a raw device: raw /dev/raw/raw1 /dev/hdd
> with /dev/hdd being my DVD drive.
> Xine then does repeated llseeks on /dev/raw/raw1 until it gets above 4G.
> Because /dev/raw/raw1 and the associated /dev/hdd both are on reiserfs,
> and reiserfs has a 4G limit, llseek assumes the same for the associated
> raw devices and returns from the llseek with EINVAL. Bang. 
> I don't know whether there's an easy solution. 

That sounds like /dev/raw/.. should have its own lseek method.

Alan

Re: [xine-user] Re: why raw devices don't seek above 4GB (sometimes)

[k.lichtenwalder]

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Alan Cox wrote:
> 
> > I set up a raw device: raw /dev/raw/raw1 /dev/hdd
> > with /dev/hdd being my DVD drive.
> > Xine then does repeated llseeks on /dev/raw/raw1 until it gets above 4G.
> > Because /dev/raw/raw1 and the associated /dev/hdd both are on reiserfs,
> > and reiserfs has a 4G limit, llseek assumes the same for the associated
> > raw devices and returns from the llseek with EINVAL. Bang.
> > I don't know whether there's an easy solution.
> 
> That sounds like /dev/raw/.. should have its own lseek method.

Yeah, while going to bed I thought that this can only be cured by doing
an raw-device specific lseek method, as lseek has no other means to find
out which device this really is. I guess I'll give it a try but I don't
know whether I'm up to it.

Klaus
-- 
------------------------------------------------------------------------ 
 Klaus Lichtenwalder, Dipl. Inform.,       http://www.webforum.de/Klaus/
 Fax +49-(0)89-91072699                            Lichtenwalder@ACM.org
 NIC: KL2100, KL76-RIPE                     K.Lichtenwalder@Computer.org
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C2C7

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