[PATCH v1 10/12] xprtrdma: Fix large NFS SYMLINK calls

Chuck Lever
2015-07-09T20:43:15Z

Repair how rpcrdma_marshal_req() chooses which RDMA message type
to use for large non-WRITE operations so that it picks RDMA_NOMSG
in the correct situations, and sets up the marshaling logic to
SEND only the RPC/RDMA header.

Large NFSv2 SYMLINK requests now use RDMA_NOMSG calls. The Linux NFS
server XDR decoder for NFSv2 SYMLINK does not handle having the
pathname argument arrive in a separate buffer. The decoder could be
fixed, but this is simpler and RDMA_NOMSG can be used in a variety
of other situations.

Ensure that the Linux client continues to use "RDMA_MSG + read
list" when sending large NFSv3 SYMLINK requests, which is more
efficient than using RDMA_NOMSG.

Large NFSv4 CREATE(NF4LNK) requests are changed to use "RDMA_MSG +
read list" just like NFSv3 (see Section 5 of RFC 5667). Before,
these did not work at all.

Signed-off-by: Chuck Lever <chuck.lever-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
---
fs/nfs/nfs3xdr.c | 1 +
fs/nfs/nfs4xdr.c | 1 +
net/sunrpc/xprtrdma/rpc_rdma.c | 21 ++++++++++++---------
3 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/fs/nfs/nfs3xdr.c b/fs/nfs/nfs3xdr.c
index 9b04c2e..267126d 100644
--- a/fs/nfs/nfs3xdr.c
+++ b/fs/nfs/nfs3xdr.c
@@ -1103,6 +1103,7 @@ static void nfs3_xdr_enc_symlink3args(struct rpc_rqst *req,
{
encode_diropargs3(xdr, args->fromfh, args->fromname, args->fromlen);
encode_symlinkdata3(xdr, args);
+ xdr->buf->flags |= XDRBUF_WRITE;
}

/*
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 558cd65d..03a20ec 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -1155,6 +1155,7 @@ static void encode_create(struct xdr_stream *xdr, const struct nfs4_create_arg *
p = reserve_space(xdr, 4);
*p = cpu_to_be32(create->u.symlink.len);
xdr_write_pages(xdr, create->u.symlink.pages, 0, create->u.symlink.len);
+ xdr->buf->flags |= XDRBUF_WRITE;
break;

case NF4BLK: case NF4CHR:
diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c
index 2e721f2..64fc4b4 100644
--- a/net/sunrpc/xprtrdma/rpc_rdma.c
+++ b/net/sunrpc/xprtrdma/rpc_rdma.c
@@ -484,21 +484,24 @@ rpcrdma_marshal_req(struct rpc_rqst *rqst)
*
* o If the total request is under the inline threshold, all ops
* are sent as inline.
- * o Large non-write ops are sent with the entire message as a
- * single read chunk (protocol 0-position special case).
* o Large write ops transmit data as read chunk(s), header as
* inline.
+ * o Large non-write ops are sent with the entire message as a
+ * single read chunk (protocol 0-position special case).
*
- * Note: the NFS code sending down multiple argument segments
- * implies the op is a write.
- * TBD check NFSv4 setacl
+ * This assumes that the upper layer does not present a request
+ * that both has a data payload, and whose non-data arguments
+ * by themselves are larger than the inline threshold.
*/
- if (rpcrdma_args_inline(rqst))
+ if (rpcrdma_args_inline(rqst)) {
rtype = rpcrdma_noch;
- else if (rqst->rq_snd_buf.page_len == 0)
- rtype = rpcrdma_areadch;
- else
+ } else if (rqst->rq_snd_buf.flags & XDRBUF_WRITE) {
rtype = rpcrdma_readch;
+ } else {
+ headerp->rm_type = htonl(RDMA_NOMSG);
+ rtype = rpcrdma_areadch;
+ rpclen = 0;
+ }

/* The following simplification is not true forever */
if (rtype != rpcrdma_noch && wtype == rpcrdma_replych)

--
To unsubscribe from this list: send the line "unsubscribe linux-nfs" in