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Date:      Sun, 23 Apr 2006 15:31:34 +0200
From:      Jean-Yves Lefort <jylefort@FreeBSD.org>
To:        freebsd-geom@FreeBSD.org
Subject:   multiple of sector size I/O restriction
Message-ID:  <20060423153134.63716562.jylefort@FreeBSD.org>

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In sys/geom/geom_io.c, g_io_check() I find this:

		/* Reject I/O not on sector boundary */
		if (bp->bio_offset % pp->sectorsize)
			return (EINVAL);

Which causes this:

	# dd if=3D/dev/ad1 of=3Dtest bs=3D512 count=3D1
	1+0 records in
	1+0 records out
	512 bytes transferred in 1.889527 secs (271 bytes/sec)

	# dd if=3D/dev/ad1 of=3Dtest bs=3D513 count=3D1
	dd: /dev/ad1: Invalid argument
	0+0 records in
	0+0 records out
	0 bytes transferred in 0.000254 secs (0 bytes/sec)

Why this restriction?

--=20
Jean-Yves Lefort

jylefort@FreeBSD.org
http://lefort.be.eu.org/

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