nfs optimization and veriexec

hi,

i'd like to make a change like the following, which optimize
a RPC away
in some cases.
however, i think it breaks veriexec. (specifically, breaks
assumptions
held by veriexec_openchk.)
can any veriexec people take a look and suggest how it
should be solved?

thanks.

YAMAMOTO Takashi

>i'd like to make a change like the following, which
optimize a RPC away
>in some cases.
>however, i think it breaks veriexec. (specifically,
breaks assumptions
>held by veriexec_openchk.)
>can any veriexec people take a look and suggest how it
should be solved?

I'm still using an ancient version of veriexec with several
mods,
but I think the current version has a state variable you can
check.
This would allow you to skip the optimization if veriexec is
enabled.
You could perhaps even test if the kernel has any
finger-prints loaded for 
the mounted fs - if not, then veriexec won't matter - the fs
is presumably 
being used for data only. 

--sjg
 

> hi,
> 
> i'd like to make a change like the following, which
optimize a RPC away
> in some cases.
> however, i think it breaks veriexec. (specifically,
breaks assumptions
> held by veriexec_openchk.)
> can any veriexec people take a look and suggest how it
should be solved?
> 
> thanks.
> 
> YAMAMOTO Takashi

as some people asked me to explain more...

currently, create basically works as the following,

	1. VOP_LOOKUP: issue a LOOKUP RPC to check if the file
already exists.
	2. veriexec_openchk.
	3. VOP_CREATE: issue a CREATE RPC to create a file.

the patch changes it to delegate more to nfs server.
ie.
	1. VOP_LOOKUP: just return.
	2. veriexec_openchk ???
	3. VOP_CREATE: issue a CREATE RPC to do "create a file
unless
	   it already exists."

YAMAMOTO Takashi

On Mon, Oct 29, 2007 at 07:49:59PM +0900, YAMAMOTO Takashi
wrote:
> 
> as some people asked me to explain more...
> 

I think the approach that Simon suggested is probably
workable.  If
veriexec is active on the mount then there should be a
fileassoc table
for the mount point, you can look up the handle in that
fileassoc, if
it is there then don't short circuit otherwise it is safe to
do so.

If you like I can fix that for you.

-- 
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