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From:   "Benjamin Coddington" <bcodding@redhat.com>
To:     trondmy@kernel.org
Cc:     linux-nfs@vger.kernel.org
Subject: Re: [PATCH v7 02/21] NFS: Trace lookup revalidation failure
Date:   Thu, 24 Feb 2022 09:14:46 -0500
Message-ID: <43364F7C-BEED-4C35-8745-9181AD2D9F57@redhat.com>
In-Reply-To: <20220223211305.296816-3-trondmy@kernel.org>
References: <20220223211305.296816-1-trondmy@kernel.org>
 <20220223211305.296816-2-trondmy@kernel.org>
 <20220223211305.296816-3-trondmy@kernel.org>
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On 23 Feb 2022, at 16:12, trondmy@kernel.org wrote:

> From: Trond Myklebust <trond.myklebust@hammerspace.com>
>
> Enable tracing of lookup revalidation failures.
>
> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
> ---
>  fs/nfs/dir.c | 17 +++++------------
>  1 file changed, 5 insertions(+), 12 deletions(-)
>
> diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
> index ebddc736eac2..1aa55cac9d9a 100644
> --- a/fs/nfs/dir.c
> +++ b/fs/nfs/dir.c
> @@ -1474,9 +1474,7 @@ nfs_lookup_revalidate_done(struct inode *dir, 
> struct dentry *dentry,
>  {
>  	switch (error) {
>  	case 1:
> -		dfprintk(LOOKUPCACHE, "NFS: %s(%pd2) is valid\n",
> -			__func__, dentry);
> -		return 1;
> +		break;
>  	case 0:
>  		/*
>  		 * We can't d_drop the root of a disconnected tree:
> @@ -1485,13 +1483,10 @@ nfs_lookup_revalidate_done(struct inode *dir, 
> struct dentry *dentry,
>  		 * inodes on unmount and further oopses.
>  		 */
>  		if (inode && IS_ROOT(dentry))
> -			return 1;
> -		dfprintk(LOOKUPCACHE, "NFS: %s(%pd2) is invalid\n",
> -				__func__, dentry);
> -		return 0;
> +			error = 1;
> +		break;
>  	}
> -	dfprintk(LOOKUPCACHE, "NFS: %s(%pd2) lookup returned error %d\n",
> -				__func__, dentry, error);
> +	trace_nfs_lookup_revalidate_exit(dir, dentry, 0, error);


There's a path through nfs4_lookup_revalidate that will now only produce
this exit tracepoint.  Does it need the _enter tracepoint added?

Ben