Re: silent semantic changes with reiser4

[Linus Torvalds]

On Thu, 26 Aug 2004, Rik van Riel wrote:
> 
> So you'd have both a file and a directory that just happen
> to have the same name ?  How would this work in the dcache?

There would be only one entry in the dcache. The lookup will select 
whether it opens the file or the directory based on O_DIRECTORY (and 
usage, of course - if it's in the middle of a path, it obviously needs to 
be opened as a directory regardless).

That's not the problem. The problem from a dcache standpoint ends up being 
when the file has a link, and you have two paths to the same sub-file 
through two different ways:

	.. create file 'x' with named stream 'y' ...
	ln x z
	ls -l x/y z/y	/* it's the same attribute!! */

but this is actually exactly the same thing that we already have with 
mounts, ie it is equivalent (from a dentry standpoint) to

	.. create directory 'x' with file 'y' ..
	mkdir z
	mount --bind x z
	ls -l x/y z/y	/* It's the same file!! */

so none of this is really anything "new" from a dcache standpoint.

Except for all the details, of course ;)

		Linus
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