Re: Getting FS access events

From: "H. Peter Anvin" <hpa@transmeta.com>
To: "Albert D. Cahalan" <acahalan@cs.uml.edu>
Cc: "H. Peter Anvin" <hpa@zytor.com>, linux-kernel@vger.kernel.org
Subject: Re: Getting FS access events
Date: Tue, 15 May 2001 15:35:53 -0700	[thread overview]
Message-ID: <3B01AF49.A66DB880@transmeta.com> (raw)
In-Reply-To: <200105152231.f4FMVSC246046@saturn.cs.uml.edu>

"Albert D. Cahalan" wrote:
> 
> H. Peter Anvin writes:
> 
> > This would leave no way (without introducing new interfaces) to write,
> > for example, the boot block on an ext2 filesystem.  Note that the
> > bootblock (defined as the first 1024 bytes) is not actually used by
> > the filesystem, although depending on the block size it may share a
> > block with the superblock (if blocksize > 1024).
> 
> The lack of coherency would screw this up anyway, doesn't it?
> You have a block device, soon to be in the page cache, and
> a superblock, also soon to be in the page cache. LILO writes to
> the block device, while the ext2 driver updates the superblock.
> Whatever gets written out last wins, and the other is lost.
> 

Albert, I *did* say "this better work or we have a problem."

	-hpa

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