From:   Chuck Lever III <chuck.lever@oracle.com>
To:     "trondmy@kernel.org" <trondmy@kernel.org>
CC:     Bruce Fields <bfields@redhat.com>,
        Linux NFS Mailing List <linux-nfs@vger.kernel.org>
Subject: Re: [PATCH v2 06/10] nfsd: NFSv3 should allow zero length writes
Thread-Topic: [PATCH v2 06/10] nfsd: NFSv3 should allow zero length writes
Thread-Index: AQHX9HoH/q0FBtAROkub7IvP/pGPwKw6QECA
Date:   Sun, 19 Dec 2021 20:11:28 +0000
Message-ID: <26FE2634-B4BC-4E90-AE2D-9B37A2F4D8B2@oracle.com>
References: <20211219013803.324724-1-trondmy@kernel.org>
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In-Reply-To: <20211219013803.324724-7-trondmy@kernel.org>
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> On Dec 18, 2021, at 8:37 PM, trondmy@kernel.org wrote:
>=20
> From: Trond Myklebust <trond.myklebust@hammerspace.com>
>=20
> According to RFC1813: "If count is 0, the WRITE will succeed
> and return a count of 0, barring errors due to permissions checking."

If you resend this series, please move this patch to the front.


> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
> ---
> fs/nfsd/vfs.c    | 3 +++
> net/sunrpc/svc.c | 2 +-
> 2 files changed, 4 insertions(+), 1 deletion(-)
>=20
> diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
> index eb9818432149..85e579aa6944 100644
> --- a/fs/nfsd/vfs.c
> +++ b/fs/nfsd/vfs.c
> @@ -967,6 +967,9 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh =
*fhp, struct nfsd_file *nf,
>=20
> 	trace_nfsd_write_opened(rqstp, fhp, offset, *cnt);
>=20
> +	if (!*cnt)
> +		return nfs_ok;
> +
> 	if (sb->s_export_op)
> 		exp_op_flags =3D sb->s_export_op->flags;
>=20
> diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
> index 4292278a9552..72a7822fd257 100644
> --- a/net/sunrpc/svc.c
> +++ b/net/sunrpc/svc.c
> @@ -1638,7 +1638,7 @@ unsigned int svc_fill_write_vector(struct svc_rqst =
*rqstp,
> 	 * entirely in rq_arg.pages. In this case, @first is empty.
> 	 */
> 	i =3D 0;
> -	if (first->iov_len) {
> +	if (first->iov_len || !total) {
> 		vec[i].iov_base =3D first->iov_base;
> 		vec[i].iov_len =3D min_t(size_t, total, first->iov_len);
> 		total -=3D vec[i].iov_len;
> --=20
> 2.33.1
>=20

--
Chuck Lever