On Mon, Aug 17, 2020 at 12:53:07PM -0400, schumaker.anna@xxxxxxxxx wrote:
> From: Anna Schumaker <Anna.Schumaker@xxxxxxxxxx>
>
> This patch adds READ_PLUS support for returning a single
> NFS4_CONTENT_DATA segment to the client. This is basically the same as
> the READ operation, only with the extra information about data segments.
>
> Signed-off-by: Anna Schumaker <Anna.Schumaker@xxxxxxxxxx>
> ---
> fs/nfsd/nfs4proc.c | 17 ++++++++++
> fs/nfsd/nfs4xdr.c | 83 ++++++++++++++++++++++++++++++++++++++++++++--
> 2 files changed, 98 insertions(+), 2 deletions(-)
>
> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
> index a09c35f0f6f0..9630d33211f2 100644
> --- a/fs/nfsd/nfs4proc.c
> +++ b/fs/nfsd/nfs4proc.c
> @@ -2523,6 +2523,16 @@ static inline u32 nfsd4_read_rsize(struct svc_rqst *rqstp, struct nfsd4_op *op)
> return (op_encode_hdr_size + 2 + XDR_QUADLEN(rlen)) * sizeof(__be32);
> }
>
> +static inline u32 nfsd4_read_plus_rsize(struct svc_rqst *rqstp, struct nfsd4_op *op)
> +{
> + u32 maxcount = svc_max_payload(rqstp);
> + u32 rlen = min(op->u.read.rd_length, maxcount);
> + /* enough extra xdr space for encoding either a hole or data segment. */
> + u32 segments = 1 + 2 + 2;
> +
> + return (op_encode_hdr_size + 2 + segments + XDR_QUADLEN(rlen)) * sizeof(__be32);
I'm not sure I understand this calculation.
In the final code, there's no fixed limit on the number of segments
returned by a single READ_PLUS op, right?
--b.
> +}
> +
> static inline u32 nfsd4_readdir_rsize(struct svc_rqst *rqstp, struct nfsd4_op *op)
> {
> u32 maxcount = 0, rlen = 0;
> @@ -3059,6 +3069,13 @@ static const struct nfsd4_operation nfsd4_ops[] = {
> .op_name = "OP_COPY",
> .op_rsize_bop = nfsd4_copy_rsize,
> },
> + [OP_READ_PLUS] = {
> + .op_func = nfsd4_read,
> + .op_release = nfsd4_read_release,
> + .op_name = "OP_READ_PLUS",
> + .op_rsize_bop = nfsd4_read_plus_rsize,
> + .op_get_currentstateid = nfsd4_get_readstateid,
> + },
> [OP_SEEK] = {
> .op_func = nfsd4_seek,
> .op_name = "OP_SEEK",
> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
> index 6a1c0a7fae05..9af92f538000 100644
> --- a/fs/nfsd/nfs4xdr.c
> +++ b/fs/nfsd/nfs4xdr.c
> @@ -1957,7 +1957,7 @@ static const nfsd4_dec nfsd4_dec_ops[] = {
> [OP_LAYOUTSTATS] = (nfsd4_dec)nfsd4_decode_notsupp,
> [OP_OFFLOAD_CANCEL] = (nfsd4_dec)nfsd4_decode_offload_status,
> [OP_OFFLOAD_STATUS] = (nfsd4_dec)nfsd4_decode_offload_status,
> - [OP_READ_PLUS] = (nfsd4_dec)nfsd4_decode_notsupp,
> + [OP_READ_PLUS] = (nfsd4_dec)nfsd4_decode_read,
> [OP_SEEK] = (nfsd4_dec)nfsd4_decode_seek,
> [OP_WRITE_SAME] = (nfsd4_dec)nfsd4_decode_notsupp,
> [OP_CLONE] = (nfsd4_dec)nfsd4_decode_clone,
> @@ -4367,6 +4367,85 @@ nfsd4_encode_offload_status(struct nfsd4_compoundres *resp, __be32 nfserr,
> return nfserr_resource;
> p = xdr_encode_hyper(p, os->count);
> *p++ = cpu_to_be32(0);
> + return nfserr;
> +}
> +
> +static __be32
> +nfsd4_encode_read_plus_data(struct nfsd4_compoundres *resp,
> + struct nfsd4_read *read,
> + unsigned long maxcount, u32 *eof)
> +{
> + struct xdr_stream *xdr = &resp->xdr;
> + struct file *file = read->rd_nf->nf_file;
> + int starting_len = xdr->buf->len;
> + __be32 nfserr;
> + __be32 *p, tmp;
> + __be64 tmp64;
> +
> + /* Content type, offset, byte count */
> + p = xdr_reserve_space(xdr, 4 + 8 + 4);
> + if (!p)
> + return nfserr_resource;
> +
> + read->rd_vlen = xdr_reserve_space_vec(xdr, resp->rqstp->rq_vec, maxcount);
> + if (read->rd_vlen < 0)
> + return nfserr_resource;
> +
> + nfserr = nfsd_readv(resp->rqstp, read->rd_fhp, file, read->rd_offset,
> + resp->rqstp->rq_vec, read->rd_vlen, &maxcount, eof);
> + if (nfserr)
> + return nfserr;
> +
> + tmp = htonl(NFS4_CONTENT_DATA);
> + write_bytes_to_xdr_buf(xdr->buf, starting_len, &tmp, 4);
> + tmp64 = cpu_to_be64(read->rd_offset);
> + write_bytes_to_xdr_buf(xdr->buf, starting_len + 4, &tmp64, 8);
> + tmp = htonl(maxcount);
> + write_bytes_to_xdr_buf(xdr->buf, starting_len + 12, &tmp, 4);
> + return nfs_ok;
> +}
> +
> +static __be32
> +nfsd4_encode_read_plus(struct nfsd4_compoundres *resp, __be32 nfserr,
> + struct nfsd4_read *read)
> +{
> + unsigned long maxcount;
> + struct xdr_stream *xdr = &resp->xdr;
> + struct file *file;
> + int starting_len = xdr->buf->len;
> + int segments = 0;
> + __be32 *p, tmp;
> + u32 eof;
> +
> + if (nfserr)
> + return nfserr;
> + file = read->rd_nf->nf_file;
> +
> + /* eof flag, segment count */
> + p = xdr_reserve_space(xdr, 4 + 4);
> + if (!p)
> + return nfserr_resource;
> + xdr_commit_encode(xdr);
> +
> + maxcount = svc_max_payload(resp->rqstp);
> + maxcount = min_t(unsigned long, maxcount,
> + (xdr->buf->buflen - xdr->buf->len));
> + maxcount = min_t(unsigned long, maxcount, read->rd_length);
> +
> + eof = read->rd_offset >= i_size_read(file_inode(file));
> + if (!eof) {
> + nfserr = nfsd4_encode_read_plus_data(resp, read, maxcount, &eof);
> + segments++;
> + }
> +
> + if (nfserr)
> + xdr_truncate_encode(xdr, starting_len);
> + else {
> + tmp = htonl(eof);
> + write_bytes_to_xdr_buf(xdr->buf, starting_len, &tmp, 4);
> + tmp = htonl(segments);
> + write_bytes_to_xdr_buf(xdr->buf, starting_len + 4, &tmp, 4);
> + }
>
> return nfserr;
> }
> @@ -4509,7 +4588,7 @@ static const nfsd4_enc nfsd4_enc_ops[] = {
> [OP_LAYOUTSTATS] = (nfsd4_enc)nfsd4_encode_noop,
> [OP_OFFLOAD_CANCEL] = (nfsd4_enc)nfsd4_encode_noop,
> [OP_OFFLOAD_STATUS] = (nfsd4_enc)nfsd4_encode_offload_status,
> - [OP_READ_PLUS] = (nfsd4_enc)nfsd4_encode_noop,
> + [OP_READ_PLUS] = (nfsd4_enc)nfsd4_encode_read_plus,
> [OP_SEEK] = (nfsd4_enc)nfsd4_encode_seek,
> [OP_WRITE_SAME] = (nfsd4_enc)nfsd4_encode_noop,
> [OP_CLONE] = (nfsd4_enc)nfsd4_encode_noop,
> --
> 2.28.0
>
