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From: R.E.Wolff@BitWizard.nl (Rogier Wolff)
To: mingo@redhat.com,
	Linux kernel mailing list <linux-kernel@vger.kernel.org>,
	viro@math.psu.edu
Subject: RAID superblock....
Date: Sun, 10 Mar 2002 14:28:57 +0100 (MET)	[thread overview]
Message-ID: <200203101328.OAA15987@cave.bitwizard.nl> (raw)


Hi,

The MD code I see doing: 


488         sb_offset = calc_dev_sboffset(rdev->dev, rdev->mddev, 1);
489         rdev->sb_offset = sb_offset;
490         fsync_dev(dev);
491         set_blocksize (dev, MD_SB_BYTES);
492         bh = bread (dev, sb_offset / MD_SB_BLOCKS, MD_SB_BYTES);


where sb_offset is calculated as: 

290         if (blk_size[MAJOR(dev)])
291                 size = blk_size[MAJOR(dev)][MINOR(dev)];

Now, for aguments sake, I have a 4k disk. I'd expect the size to be 4
(1k blocks, according to the comment near the definition of blk_size). 

Thus the "bread" would effectively try to read the block at offset 4k. 

That would be past the end of my mini-disk, right?

I would have expected a "-1" in there somewhere, to get the last block
of the dev, and not the block just past the end of the drive.

Anyway on the old machine, I still cannot find the raid superblock by
hand, but the drives now mount, so the kernel must have been able to
locate them somehow......

The machine is still running 2.4.16 + IDE patches for 48 bit
addressing.

The working machine is an 850MHz PIII w/384Mb RAM, the non-working
machine is an AMD 1800+ MP w/1G RAM (with another one of those
processors sitting idle close by)...

				Roger. 

-- 
** R.E.Wolff@BitWizard.nl ** http://www.BitWizard.nl/ ** +31-15-2137555 **
*-- BitWizard writes Linux device drivers for any device you may have! --*
* There are old pilots, and there are bold pilots. 
* There are also old, bald pilots. 

             reply	other threads:[~2002-03-10 13:29 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-03-10 13:28 Rogier Wolff [this message]
2002-03-10 23:34 ` RAID superblock Neil Brown
  -- strict thread matches above, loose matches on Subject: below --
2004-09-08 17:41 raid superblock rich turner
     [not found] <20001025171255.26384.qmail@web6104.mail.yahoo.com>
     [not found] ` <Pine.LNX.4.21.0010261534490.9868-100000@server.serve.me.nl>
2000-10-26 16:19   ` RAID superblock Wakko Warner
2000-10-29 10:40     ` Peter Samuelson
2000-10-29 13:36       ` Igmar Palsenberg
2000-10-29 12:52         ` Wakko Warner

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