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Date: Sat, 8 Mar 2008 21:02:26 GMT
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To: dev@26th.net, rwatson@FreeBSD.org, freebsd-bugs@FreeBSD.org
From: rwatson@FreeBSD.org
Cc: 
Subject: Re: kern/94269: [nullfs] procfs shows wrong data if executable is
	running from nullfs
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Synopsis: [nullfs] procfs shows wrong data if executable is running from nullfs

State-Changed-From-To: open->suspended
State-Changed-By: rwatson
State-Changed-When: Sat Mar 8 20:59:03 UTC 2008
State-Changed-Why: 
This is an accurate bug report -- procfs and other related tools rely on
the name cache to generate names for file system objects on demand.
However, nullfs doesn't use the name cache, as the underlying file system
layer will already be performing its own caching on the name space.

Transition this to suspended as it's not clear what the right fix for
this is.  From a performance perspective, it doesn't make a lot of sense
to use the name cache for nullfs, and there is otherwise no good source
of name data with which to build a name for an arbitrary vnode.  There is
also no cache invalidation of "higher layers" with file system stacking
for the name cache, so quite a lot of work would have to be done in order
to implement it with proper name cache invalidation.

Thanks for the report; hopefully we can interest someone in further
investigating this in the future.


http://www.freebsd.org/cgi/query-pr.cgi?pr=94269