NFSD: Hoist status code encoding into XDR encoder functions

The original intent was presumably to reduce code duplication. The
trade-off was:

- No support for an NFSD proc function returning a non-success
  RPC accept_stat value.
- No support for void NFS replies to non-NULL procedures.
- Everyone pays for the deduplication with a few extra conditional
  branches in a hot path.

In addition, nfsd_dispatch() leaves *statp uninitialized in the
success path, unlike svc_generic_dispatch().

Address all of these problems by moving the logic for encoding
the NFS status code into the NFS XDR encoders themselves. Then
update the NFS .pc_func methods to return an RPC accept_stat
value.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 15 insertions, 4 deletions

diff --git a/fs/nfsd/nfs3xdr.c b/fs/nfsd/nfs3xdr.c
index e540fd1a29d8..9c23b6acf234 100644
--- a/fs/nfsd/nfs3xdr.c
+++ b/fs/nfsd/nfs3xdr.c
@@ -641,10 +641,7 @@ nfs3svc_decode_commitargs(struct svc_rqst *rqstp, __be32 *p)
 /*
  * XDR encode functions
  */
-/*
- * There must be an encoding function for void results so svc_process
- * will work properly.
- */
+
 int
 nfs3svc_encode_voidres(struct svc_rqst *rqstp, __be32 *p)
 {
@@ -657,6 +654,7 @@ nfs3svc_encode_attrstat(struct svc_rqst *rqstp, __be32 *p)
 {
 	struct nfsd3_attrstat *resp = rqstp->rq_resp;
 
+	*p++ = resp->status;
 	if (resp->status == 0) {
 		lease_get_mtime(d_inode(resp->fh.fh_dentry),
 				&resp->stat.mtime);
@@ -671,6 +669,7 @@ nfs3svc_encode_wccstat(struct svc_rqst *rqstp, __be32 *p)
 {
 	struct nfsd3_attrstat *resp = rqstp->rq_resp;
 
+	*p++ = resp->status;
 	p = encode_wcc_data(rqstp, p, &resp->fh);
 	return xdr_ressize_check(rqstp, p);
 }
@@ -681,6 +680,7 @@ nfs3svc_encode_diropres(struct svc_rqst *rqstp, __be32 *p)
 {
 	struct nfsd3_diropres *resp = rqstp->rq_resp;
 
+	*p++ = resp->status;
 	if (resp->status == 0) {
 		p = encode_fh(p, &resp->fh);
 		p = encode_post_op_attr(rqstp, p, &resp->fh);
@@ -695,6 +695,7 @@ nfs3svc_encode_accessres(struct svc_rqst *rqstp, __be32 *p)
 {
 	struct nfsd3_accessres *resp = rqstp->rq_resp;
 
+	*p++ = resp->status;
 	p = encode_post_op_attr(rqstp, p, &resp->fh);
 	if (resp->status == 0)
 		*p++ = htonl(resp->access);
@@ -707,6 +708,7 @@ nfs3svc_encode_readlinkres(struct svc_rqst *rqstp, __be32 *p)
 {
 	struct nfsd3_readlinkres *resp = rqstp->rq_resp;
 
+	*p++ = resp->status;
 	p = encode_post_op_attr(rqstp, p, &resp->fh);
 	if (resp->status == 0) {
 		*p++ = htonl(resp->len);
@@ -729,6 +731,7 @@ nfs3svc_encode_readres(struct svc_rqst *rqstp, __be32 *p)
 {
 	struct nfsd3_readres *resp = rqstp->rq_resp;
 
+	*p++ = resp->status;
 	p = encode_post_op_attr(rqstp, p, &resp->fh);
 	if (resp->status == 0) {
 		*p++ = htonl(resp->count);
@@ -754,6 +757,7 @@ nfs3svc_encode_writeres(struct svc_rqst *rqstp, __be32 *p)
 {
 	struct nfsd3_writeres *resp = rqstp->rq_resp;
 
+	*p++ = resp->status;
 	p = encode_wcc_data(rqstp, p, &resp->fh);
 	if (resp->status == 0) {
 		*p++ = htonl(resp->count);
@@ -770,6 +774,7 @@ nfs3svc_encode_createres(struct svc_rqst *rqstp, __be32 *p)
 {
 	struct nfsd3_diropres *resp = rqstp->rq_resp;
 
+	*p++ = resp->status;
 	if (resp->status == 0) {
 		*p++ = xdr_one;
 		p = encode_fh(p, &resp->fh);
@@ -785,6 +790,7 @@ nfs3svc_encode_renameres(struct svc_rqst *rqstp, __be32 *p)
 {
 	struct nfsd3_renameres *resp = rqstp->rq_resp;
 
+	*p++ = resp->status;
 	p = encode_wcc_data(rqstp, p, &resp->ffh);
 	p = encode_wcc_data(rqstp, p, &resp->tfh);
 	return xdr_ressize_check(rqstp, p);
@@ -796,6 +802,7 @@ nfs3svc_encode_linkres(struct svc_rqst *rqstp, __be32 *p)
 {
 	struct nfsd3_linkres *resp = rqstp->rq_resp;
 
+	*p++ = resp->status;
 	p = encode_post_op_attr(rqstp, p, &resp->fh);
 	p = encode_wcc_data(rqstp, p, &resp->tfh);
 	return xdr_ressize_check(rqstp, p);
@@ -807,6 +814,7 @@ nfs3svc_encode_readdirres(struct svc_rqst *rqstp, __be32 *p)
 {
 	struct nfsd3_readdirres *resp = rqstp->rq_resp;
 
+	*p++ = resp->status;
 	p = encode_post_op_attr(rqstp, p, &resp->fh);
 
 	if (resp->status == 0) {
@@ -1059,6 +1067,7 @@ nfs3svc_encode_fsstatres(struct svc_rqst *rqstp, __be32 *p)
 	struct kstatfs	*s = &resp->stats;
 	u64		bs = s->f_bsize;
 
+	*p++ = resp->status;
 	*p++ = xdr_zero;	/* no post_op_attr */
 
 	if (resp->status == 0) {
@@ -1079,6 +1088,7 @@ nfs3svc_encode_fsinfores(struct svc_rqst *rqstp, __be32 *p)
 {
 	struct nfsd3_fsinfores *resp = rqstp->rq_resp;
 
+	*p++ = resp->status;
 	*p++ = xdr_zero;	/* no post_op_attr */
 
 	if (resp->status == 0) {
@@ -1124,6 +1134,7 @@ nfs3svc_encode_commitres(struct svc_rqst *rqstp, __be32 *p)
 {
 	struct nfsd3_commitres *resp = rqstp->rq_resp;
 
+	*p++ = resp->status;
 	p = encode_wcc_data(rqstp, p, &resp->fh);
 	/* Write verifier */
 	if (resp->status == 0) {