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Re: [PATCH 02/10] Updated nfsd.proc.lookup probes


On 02/25/2010 04:19 PM, Steve Dickson wrote:
> commit 472a70b44b5858c60373aa45a119ad66b804061b
> Author: Steve Dickson <steved@redhat.com>
> Date:   Tue Feb 23 11:29:06 2010 -0500
> 
>     Updated nfsd.proc.lookup probes
>     
>     Converted the nfsd.proc.lookup probes to used
>     the @cast() mechanism.
>     
>     Created the nfsd.proc4.lookup probes
>     
>     Signed-off-by: Steve Dickson <steved@redhat.com>
> 
> diff --git a/tapset/nfsd.stp b/tapset/nfsd.stp
> index df8efa8..92f682f 100644
> --- a/tapset/nfsd.stp
> +++ b/tapset/nfsd.stp
> @@ -11,10 +11,6 @@

... great use of '@cast' to remove lots of embedded C...

>  probe nfsd.proc2.lookup = kernel.function("nfsd_proc_lookup") !,
> @@ -207,7 +136,7 @@ probe nfsd.proc2.lookup = kernel.function("nfsd_proc_lookup") !,
>  	client_ip = addr_from_rqst($rqstp)
>  	proto = $rqstp->rq_prot
>          version = 2
> -	fh = __get_fh($argp,1)
> +	fh = & @cast($argp, "nfsd_diropargs", "kernel:nfsd")->fh
>  
>  	filelen = $argp->len
>  	filename = kernel_string_n($argp->name, filelen)
> @@ -222,7 +151,7 @@ probe nfsd.proc2.lookup.return = kernel.function("nfsd_proc_lookup").return !,
>  {
>  	name = "nfsd.proc2.lookup.return"
>  	version = 2
> -	retstr = sprintf("%d",$return)
> +	retstr = sprintf("%s", nfsderror($return))
>  }

This last change points out an issue we're starting to worry about -
backwards compatibility.  If a script that previously used this probe
depended on getting a string in the old format, you just broke their script.

This one is probably OK, but it is something to think about.

-- 
David Smith
dsmith@redhat.com
Red Hat
http://www.redhat.com
256.217.0141 (direct)
256.837.0057 (fax)


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