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Date: Fri, 21 Dec 2001 10:38:54 +0900
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From: Tachino Nobuhiro <tachino@open.nm.fujitsu.co.jp>
To: torvalds@transmeta.com
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        marcelo@conectiva.com.br, tachino@open.nm.fujitsu.co.jp
Subject: Re: ramdisk corruption problems - was: RE: pivot_root and initrd 	kern el panic woes
Newsgroups: linux.dev.kernel
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At Thu, 20 Dec 2001 11:46:23 -0800,
Linus Torvalds wrote:
> 
> The problem is that having buffers doesn't necessarily always mean that
> they are valid, nor that _all_ of them are valid.

  If following sequence occurs, ramdisk_readpage() may clear the valid buffer
data. I'm not sure whether this really occurs, but if it does,
I think lock_buffer()/unlock_buffer() may be required.


	CPU1					CPU2
---------------------------------------------------------------------------
	call ext2_alloc_branch()		call ramdisk_readpage()

	bh = getblk();
	lock_buffer(bh);

	write data to bh.
						ramdisk_readpage()
						if (!buffer_uptodate(bh))
							do memset()

	mark_buffer_uptodate()
	unlock_buffer(bh);
-
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