[PATCH v2 21/33] NFSD: Use xdrgen XDR functions for the NFSv3 RENAME procedure

[Chuck Lever <cel@kernel.org>]

Replace the NFSPROC3_RENAME entry in the nfsd_procedures3 array
with an entry that dispatches the xdrgen-generated
nfs_svc_decode_RENAME3args and nfs_svc_encode_RENAME3res. A
wrapper structure bridges the generated xdrgen argument type and
the legacy svc_fh representation the NFSD VFS layer still uses;
the result uses the generated RENAME3res type directly.

Filename validity is now checked by nfsd3_proc_rename() so that a
proper NFS3ERR status code can be returned to the client rather
than GARBAGE_ARGS.

The pc_argzero field is now set to zero for the NFSv3 RENAME
procedure. The xdrgen decoders are trusted to initialize all
arguments in the argp->xdrgen field, making the early defensive
memset unnecessary. The remaining argp fields are cleared as
needed.

Because nfsd3_proc_rename() now assembles the WCC data, that work
moves out of the XDR result encoder, and the references to the
file handles can be released directly by nfsd3_proc_rename(). A
separate ->pc_release callback is thus no longer needed. This
makes it straightforward to confirm that the file handles are
properly released during every error flow.

nfs3svc_decode_renameargs() and nfs3svc_encode_renameres() no
longer have any callers, so they are removed.

Signed-off-by: Chuck Lever <cel@kernel.org>
---
 fs/nfsd/nfs3proc.c | 89 +++++++++++++++++++++++++++++++++++-----------
 fs/nfsd/nfs3xdr.c  | 22 ------------
 fs/nfsd/xdr3.h     | 17 ---------
 3 files changed, 68 insertions(+), 60 deletions(-)

diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c
index e31b96bf4a80..b9f7f9d74f3f 100644
--- a/fs/nfsd/nfs3proc.c
+++ b/fs/nfsd/nfs3proc.c
@@ -177,6 +177,14 @@ struct RMDIR3args_wrapper {
 
 static_assert(offsetof(struct RMDIR3args_wrapper, xdrgen) == 0);
 
+struct RENAME3args_wrapper {
+	struct RENAME3args	xdrgen;
+	struct svc_fh		ffh;
+	struct svc_fh		tfh;
+};
+
+static_assert(offsetof(struct RENAME3args_wrapper, xdrgen) == 0);
+
 static int nfsd3_ftype3_to_mode(ftype3 ftype)
 {
 	switch (ftype) {
@@ -1348,17 +1356,57 @@ static __be32 nfsd3_proc_rmdir(struct svc_rqst *rqstp)
 	return rpc_success;
 }
 
-static __be32
-nfsd3_proc_rename(struct svc_rqst *rqstp)
+/**
+ * nfsd3_proc_rename - RENAME: Rename a file or directory
+ * @rqstp: RPC transaction context
+ *
+ * Return:
+ *   %rpc_success:		RPC executed successfully
+ *
+ * RPC synopsis:
+ *   RENAME3res NFSPROC3_RENAME(RENAME3args) = 14;
+ */
+static __be32 nfsd3_proc_rename(struct svc_rqst *rqstp)
 {
-	struct nfsd3_renameargs *argp = rqstp->rq_argp;
-	struct nfsd3_renameres *resp = rqstp->rq_resp;
+	struct RENAME3args_wrapper *argp = rqstp->rq_argp;
+	struct diropargs3 *from = &argp->xdrgen.from;
+	struct diropargs3 *to = &argp->xdrgen.to;
+	struct RENAME3res *resp = rqstp->rq_resp;
+	struct svc_fh *ffhp = &argp->ffh;
+	struct svc_fh *tfhp = &argp->tfh;
 
-	fh_copy(&resp->ffh, &argp->ffh);
-	fh_copy(&resp->tfh, &argp->tfh);
-	resp->status = nfsd_rename(rqstp, &resp->ffh, argp->fname, argp->flen,
-				   &resp->tfh, argp->tname, argp->tlen);
-	resp->status = nfsd3_map_status(resp->status);
+	nfsd3_fh3_to_svc_fh(ffhp, &from->dir);
+	nfsd3_fh3_to_svc_fh(tfhp, &to->dir);
+	resp->status = nfsd3_check_filename(from->name.data,
+					    from->name.len);
+	if (resp->status != nfs_ok)
+		goto out;
+	resp->status = nfsd3_check_filename(to->name.data,
+					    to->name.len);
+	if (resp->status != nfs_ok)
+		goto out;
+
+	resp->status = nfsd_rename(rqstp, ffhp, (char *)from->name.data,
+				   from->name.len, tfhp,
+				   (char *)to->name.data,
+				   to->name.len);
+
+out:
+	if (resp->status == nfs_ok) {
+		struct RENAME3resok *resok = &resp->u.resok;
+
+		nfsd3_fill_wcc_data(rqstp, &resok->fromdir_wcc, ffhp);
+		nfsd3_fill_wcc_data(rqstp, &resok->todir_wcc, tfhp);
+	} else {
+		struct RENAME3resfail *resfail = &resp->u.resfail;
+
+		resp->status = nfsd3_map_status(resp->status);
+		nfsd3_fill_wcc_data(rqstp, &resfail->fromdir_wcc, ffhp);
+		nfsd3_fill_wcc_data(rqstp, &resfail->todir_wcc, tfhp);
+	}
+
+	fh_put(ffhp);
+	fh_put(tfhp);
 	return rpc_success;
 }
 
@@ -1795,16 +1843,15 @@ static const struct svc_procedure nfsd_procedures3[22] = {
 		.pc_name	= "RMDIR",
 	},
 	[NFSPROC3_RENAME] = {
-		.pc_func = nfsd3_proc_rename,
-		.pc_decode = nfs3svc_decode_renameargs,
-		.pc_encode = nfs3svc_encode_renameres,
-		.pc_release = nfs3svc_release_fhandle2,
-		.pc_argsize = sizeof(struct nfsd3_renameargs),
-		.pc_argzero = sizeof(struct nfsd3_renameargs),
-		.pc_ressize = sizeof(struct nfsd3_renameres),
-		.pc_cachetype = RC_REPLBUFF,
-		.pc_xdrressize = ST+WC+WC,
-		.pc_name = "RENAME",
+		.pc_func	= nfsd3_proc_rename,
+		.pc_decode	= nfs_svc_decode_RENAME3args,
+		.pc_encode	= nfs_svc_encode_RENAME3res,
+		.pc_argsize	= sizeof(struct RENAME3args_wrapper),
+		.pc_argzero	= 0,
+		.pc_ressize	= sizeof(struct RENAME3res),
+		.pc_cachetype	= RC_REPLBUFF,
+		.pc_xdrressize	= NFS3_RENAME3res_sz,
+		.pc_name	= "RENAME",
 	},
 	[NFSPROC3_LINK] = {
 		.pc_func = nfsd3_proc_link,
@@ -1914,13 +1961,13 @@ union nfsd3_xdrstore {
 	struct REMOVE3res		removeres;
 	struct RMDIR3args_wrapper	rmdirargs;
 	struct RMDIR3res		rmdirres;
-	struct nfsd3_renameargs		renameargs;
+	struct RENAME3args_wrapper	renameargs;
+	struct RENAME3res		renameres;
 	struct nfsd3_linkargs		linkargs;
 	struct nfsd3_readdirargs	readdirargs;
 	struct READLINK3res		readlinkres;
 	struct READ3res			readres;
 	struct nfsd3_writeres		writeres;
-	struct nfsd3_renameres		renameres;
 	struct nfsd3_linkres		linkres;
 	struct nfsd3_readdirres		readdirres;
 	struct nfsd3_fsstatres		fsstatres;
diff --git a/fs/nfsd/nfs3xdr.c b/fs/nfsd/nfs3xdr.c
index 1cfc79724450..3ec835e0f364 100644
--- a/fs/nfsd/nfs3xdr.c
+++ b/fs/nfsd/nfs3xdr.c
@@ -360,17 +360,6 @@ nfs3svc_decode_fhandleargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
 	return svcxdr_decode_nfs_fh3(xdr, &args->fh);
 }
 
-bool
-nfs3svc_decode_renameargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
-{
-	struct nfsd3_renameargs *args = rqstp->rq_argp;
-
-	return svcxdr_decode_diropargs3(xdr, &args->ffh,
-					&args->fname, &args->flen) &&
-		svcxdr_decode_diropargs3(xdr, &args->tfh,
-					 &args->tname, &args->tlen);
-}
-
 bool
 nfs3svc_decode_linkargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
 {
@@ -440,17 +429,6 @@ nfs3svc_decode_commitargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
  * XDR encode functions
  */
 
-/* RENAME */
-bool
-nfs3svc_encode_renameres(struct svc_rqst *rqstp, struct xdr_stream *xdr)
-{
-	struct nfsd3_renameres *resp = rqstp->rq_resp;
-
-	return svcxdr_encode_nfsstat3(xdr, resp->status) &&
-		svcxdr_encode_wcc_data(rqstp, xdr, &resp->ffh) &&
-		svcxdr_encode_wcc_data(rqstp, xdr, &resp->tfh);
-}
-
 /* LINK */
 bool
 nfs3svc_encode_linkres(struct svc_rqst *rqstp, struct xdr_stream *xdr)
diff --git a/fs/nfsd/xdr3.h b/fs/nfsd/xdr3.h
index fac60fb4cdf9..8a15781d7f3c 100644
--- a/fs/nfsd/xdr3.h
+++ b/fs/nfsd/xdr3.h
@@ -24,15 +24,6 @@ struct nfsd3_accessargs {
 	__u32			access;
 };
 
-struct nfsd3_renameargs {
-	struct svc_fh		ffh;
-	char *			fname;
-	unsigned int		flen;
-	struct svc_fh		tfh;
-	char *			tname;
-	unsigned int		tlen;
-};
-
 struct nfsd3_linkargs {
 	struct svc_fh		ffh;
 	struct svc_fh		tfh;
@@ -85,12 +76,6 @@ struct nfsd3_writeres {
 
 static_assert(offsetof(struct nfsd3_writeres, xdrgen) == 0);
 
-struct nfsd3_renameres {
-	__be32			status;
-	struct svc_fh		ffh;
-	struct svc_fh		tfh;
-};
-
 struct nfsd3_linkres {
 	__be32			status;
 	struct svc_fh		tfh;
@@ -165,14 +150,12 @@ struct nfsd3_fhandle_pair {
 };
 
 bool nfs3svc_decode_fhandleargs(struct svc_rqst *rqstp, struct xdr_stream *xdr);
-bool nfs3svc_decode_renameargs(struct svc_rqst *rqstp, struct xdr_stream *xdr);
 bool nfs3svc_decode_linkargs(struct svc_rqst *rqstp, struct xdr_stream *xdr);
 bool nfs3svc_decode_readdirargs(struct svc_rqst *rqstp, struct xdr_stream *xdr);
 bool nfs3svc_decode_readdirplusargs(struct svc_rqst *rqstp, struct xdr_stream *xdr);
 bool nfs3svc_decode_commitargs(struct svc_rqst *rqstp, struct xdr_stream *xdr);
 
 bool nfs3svc_encode_accessres(struct svc_rqst *rqstp, struct xdr_stream *xdr);
-bool nfs3svc_encode_renameres(struct svc_rqst *rqstp, struct xdr_stream *xdr);
 bool nfs3svc_encode_linkres(struct svc_rqst *rqstp, struct xdr_stream *xdr);
 bool nfs3svc_encode_readdirres(struct svc_rqst *rqstp, struct xdr_stream *xdr);
 bool nfs3svc_encode_fsstatres(struct svc_rqst *rqstp, struct xdr_stream *xdr);
-- 
2.55.0