Date: Sun, 19 Aug 2007 07:26:16 +0000 From: "Poul-Henning Kamp" <phk@phk.freebsd.dk> To: Graham <gbradley@rocketmail.com> Cc: sos@FreeBSD.org, freebsd-geom@FreeBSD.org Subject: Re: kern/115572: ata disk bug (was: [gbde] gbde partitions fail at 28bit/48bit LBA addressing boundary ) Message-ID: <83156.1187508376@critter.freebsd.dk> In-Reply-To: Your message of "Sat, 18 Aug 2007 21:20:11 GMT." <200708182120.l7ILKBvF046099@freefall.freebsd.org>
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In message <200708182120.l7ILKBvF046099@freefall.freebsd.org>, Graham writes: > 2. attempt (say).... > rabbit# dd if=/dev/zero of=/dev/ad4s1 oseek=2097151 count=1 bs=64k > and the result is.... > dd: /dev/ad4s1: Input/output error > 1+0 records in > 0+0 records out > 0 bytes transferred in 0.000325 secs (0 bytes/sec) > > (If dd is performed on the raw drive, /dev/ad4 then block boundary is > always a power of 2, and blocksize a smaller power of 2. That's always > ok. But we can't assume we use drives that way.) > > So a transfer which starts in the 28-bit zone, but extends over into > the 48-bit region, fails. Such transfers happen in the superblock of > certain size drives, and that plays havoc. The sector mapping of gbde > can do this, but soft-update gets screwed by this happening. It's not > actually to do with the crypto as I first suspected. This is a problem in the ata disk driver. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.
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