linux-kernel - Re: [patch] nfsd: remove some dead code in nfsd_create

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Message-ID: <20160803205042.GC5901@fieldses.org>
Date:	Wed, 3 Aug 2016 16:50:42 -0400
From:	"J. Bruce Fields" <bfields@...ldses.org>
To:	Dan Carpenter <dan.carpenter@...cle.com>
Cc:	Jeff Layton <jlayton@...chiereds.net>, linux-nfs@...r.kernel.org,
	linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: Re: [patch] nfsd: remove some dead code in nfsd_create_locked()

On Wed, Aug 03, 2016 at 10:05:00PM +0300, Dan Carpenter wrote:
> We changed this around in f13058a93484 ('nfsd: reorganize nfsd_create')
> so "dchild" can't be an error pointer any more.  Also we don't need to
> test if dchild is NULL because dput has a check built-in.

Thanks!

> Can it even be NULL?

It was returned from a caller's lookup_one_len, which can only return
pointers or errors, I believe.  (And looks like callers also do
fh_verify and would already oops if it was null.)

Anyway, added a brief comment to that effect, fixed up the referenced
commitid (I rewrote some history there, apologies) and committed, will
push out after a few tests....

--b.

> 
> Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
> 
> diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
> index c844fd6..cd628ce 100644
> --- a/fs/nfsd/vfs.c
> +++ b/fs/nfsd/vfs.c
> @@ -1141,7 +1141,7 @@ nfsd_create_locked(struct svc_rqst *rqstp, struct svc_fh *fhp,
>  		char *fname, int flen, struct iattr *iap,
>  		int type, dev_t rdev, struct svc_fh *resfhp)
>  {
> -	struct dentry	*dentry, *dchild = NULL;
> +	struct dentry	*dentry, *dchild;
>  	struct inode	*dirp;
>  	__be32		err;
>  	__be32		err2;
> @@ -1208,8 +1208,7 @@ nfsd_create_locked(struct svc_rqst *rqstp, struct svc_fh *fhp,
>  	if (!err)
>  		err = fh_update(resfhp);
>  out:
> -	if (dchild && !IS_ERR(dchild))
> -		dput(dchild);
> +	dput(dchild);
>  	return err;
>  
>  out_nfserr: