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From: "Thomas S. Iversen" <zensonic@zensonic.dk>
To: linux-kernel@vger.kernel.org
Subject: How to do IO across hardsector boundries
Date: Sun, 01 Aug 2004 02:22:15 +0200	[thread overview]
Message-ID: <410C37B7.3010504@zensonic.dk> (raw)

Hi There

As part of an assignment I am trying to port a piece of software from 
FreeBSD to linux. Essentially this software (crypto) makes a virtual 
blockdevice with "virtual" sectors on top. Under FreeBSD these virtual 
sectors are just read/written using a simple command:

buf=g_read(dev, offset, len)
error=g_write(dev,offset,buf,len)

In linux however I have only seen the BIO layer which operates on IO on 
hardsector boundaries.

So my question really is, how do I go about updating for instance the 
512 bytes located for at byte 64 to 64+511 on the actual media without 
getting in trouble regarding the data from offset 0-63 and 64+512->1023?

Regards Thomas

             reply	other threads:[~2004-08-01  0:22 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-08-01  0:22 Thomas S. Iversen [this message]
2004-07-31 23:32 ` How to do IO across hardsector boundries Alan Cox
2004-08-01  8:53 ` Arjan van de Ven
2004-08-01 13:10 ` Richard B. Johnson

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