linux-kernel - Re: [PATCH] nfsd: remove unnecessary assertion in nfsd4_layout

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Message-ID: <20200103154309.GA23945@fieldses.org>
Date:   Fri, 3 Jan 2020 10:43:09 -0500
From:   "J. Bruce Fields" <bfields@...ldses.org>
To:     Aditya Pakki <pakki001@....edu>
Cc:     kjlu@....edu, Chuck Lever <chuck.lever@...cle.com>,
        linux-nfs@...r.kernel.org, linux-kernel@...r.kernel.org,
        Christoph Hellwig <hch@....de>
Subject: Re: [PATCH] nfsd: remove unnecessary assertion in
 nfsd4_layout_setlease

It took me a minute to see how fl can even fail to be NULL, since we
just accessed fields of fl.

OK, I see, &fl is passed to vfs_setlease, so it can change the value of
fl.

Looks like generic_addlease() clears flp on success, unless it finds an
existing non-conflicting lease?  I'm not clear why nfsd4_layout_setlease
knows it can't hit that case.

In any case, I don't see why this assertion is redundant; leaving it
there.

--b.

On Thu, Dec 26, 2019 at 02:37:33PM -0600, Aditya Pakki wrote:
> In nfsd4_layout_setlease, checking for a valid file lock is
> redundant and can be removed. This patch eliminates such a
> BUG_ON check.
> 
> Signed-off-by: Aditya Pakki <pakki001@....edu>
> ---
>  fs/nfsd/nfs4layouts.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/fs/nfsd/nfs4layouts.c b/fs/nfsd/nfs4layouts.c
> index 2681c70283ce..ef5f8e645f4f 100644
> --- a/fs/nfsd/nfs4layouts.c
> +++ b/fs/nfsd/nfs4layouts.c
> @@ -204,7 +204,6 @@ nfsd4_layout_setlease(struct nfs4_layout_stateid *ls)
>  		locks_free_lock(fl);
>  		return status;
>  	}
> -	BUG_ON(fl != NULL);
>  	return 0;
>  }
>  
> -- 
> 2.20.1