Re: [RFC PATCH] file as directory

[Al Viro]

On Wed, May 23, 2007 at 10:05:21AM +0200, Miklos Szeredi wrote:
> > Er...  These mounts might not be propagated, but what about a bind
> > over another instance of such file in master tree?
> 
> So your question is, which mount takes priority on the lookup?  It
> probably should be the propagated real mount, rather than the
> dir-on-file one, shouldn't it?

There might be dragons in that area...
 
> > > I think they should be the same superblock, same dentry.  What would
> > > be the advantage of doing otherwise?
> > 
> > Then you are going to have interesting time with locking in final mntput().
> 
> Final mntput of what?

When the last reference to your mount goes away.
 
> > BTW, what about having several links to the same file?  You have i_mutex
> > on the inode, so serialization of those is not a problem, but...
> 
> Sorry, I lost it...

Say /foo/bar/a is such a file.

cd /foo/bar
ln a b

now do lookups on a/ and b/

What happens?
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