Re: [PATCH 1/1] NFSD: fix leak referent count of nfsd4_ssc_umount_item in nfsd4_copy

[Jeff Layton <jlayton@kernel.org>]

On Mon, 2023-01-23 at 21:34 -0800, Dai Ngo wrote:
> The reference count of nfsd4_ssc_umount_item is not decremented
> on error conditions. This prevents the laundromat from unmounting
> the vfsmount of the source file.
> 
> This patch decrements the reference count of nfsd4_ssc_umount_item
> on error.
> 
> Fixes: f4e44b393389 ("NFSD: delay unmount source's export after inter-server copy completed.")
> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
> ---
>  fs/nfsd/nfs4proc.c | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
> index b4e7e18e1761..889b603619c3 100644
> --- a/fs/nfsd/nfs4proc.c
> +++ b/fs/nfsd/nfs4proc.c
> @@ -1821,13 +1821,17 @@ nfsd4_copy(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
>  out:
>  	return status;
>  out_err:
> +	if (nfsd4_ssc_is_inter(copy)) {
> +		/*
> +		 * Source's vfsmount of inter-copy will be unmounted
> +		 * by the laundromat. Use copy instead of async_copy
> +		 * since async_copy->ss_nsui might not be set yet.
> +	 	*/
> +		refcount_dec(&copy->ss_nsui->nsui_refcnt);
> +	}
>  	if (async_copy)
>  		cleanup_async_copy(async_copy);
>  	status = nfserrno(-ENOMEM);
> -	/*
> -	 * source's vfsmount of inter-copy will be unmounted
> -	 * by the laundromat
> -	 */
>  	goto out;
>  }
>  

Looks good.

Reviewed-by: Jeff Layton <jlayton@kernel.org>