[PATCH v2 20/33] NFSD: Use xdrgen XDR functions for the NFSv3 RMDIR procedure

[Chuck Lever <cel@kernel.org>]

Replace the NFSPROC3_RMDIR entry in the nfsd_procedures3 array
with an entry that dispatches the xdrgen-generated
nfs_svc_decode_RMDIR3args and nfs_svc_encode_RMDIR3res. 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 RMDIR3res type directly.

Filename validity is now checked by nfsd3_proc_rmdir() 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 RMDIR
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_rmdir() now assembles the WCC data, that work
moves out of the XDR result encoder, and the reference to the
file handle can be released directly by nfsd3_proc_rmdir(). A
separate ->pc_release callback is thus no longer needed. This
makes it straightforward to confirm that the file handle is
properly released during every error flow.

nfs3svc_decode_diropargs() and nfs3svc_encode_wccstat() no longer
have any callers, so they are removed.

Signed-off-by: Chuck Lever <cel@kernel.org>
---
 fs/nfsd/nfs3proc.c | 74 ++++++++++++++++++++++++++++++++--------------
 fs/nfsd/nfs3xdr.c  | 18 -----------
 fs/nfsd/xdr3.h     |  8 -----
 3 files changed, 51 insertions(+), 49 deletions(-)

diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c
index 02c7501c8663..e31b96bf4a80 100644
--- a/fs/nfsd/nfs3proc.c
+++ b/fs/nfsd/nfs3proc.c
@@ -170,6 +170,13 @@ struct REMOVE3args_wrapper {
 
 static_assert(offsetof(struct REMOVE3args_wrapper, xdrgen) == 0);
 
+struct RMDIR3args_wrapper {
+	struct RMDIR3args	xdrgen;
+	struct svc_fh		fh;
+};
+
+static_assert(offsetof(struct RMDIR3args_wrapper, xdrgen) == 0);
+
 static int nfsd3_ftype3_to_mode(ftype3 ftype)
 {
 	switch (ftype) {
@@ -1302,19 +1309,42 @@ static __be32 nfsd3_proc_remove(struct svc_rqst *rqstp)
 	return rpc_success;
 }
 
-/*
- * Remove a directory
+/**
+ * nfsd3_proc_rmdir - RMDIR: Remove a directory
+ * @rqstp: RPC transaction context
+ *
+ * Return:
+ *   %rpc_success:		RPC executed successfully
+ *
+ * RPC synopsis:
+ *   RMDIR3res NFSPROC3_RMDIR(RMDIR3args) = 13;
  */
-static __be32
-nfsd3_proc_rmdir(struct svc_rqst *rqstp)
+static __be32 nfsd3_proc_rmdir(struct svc_rqst *rqstp)
 {
-	struct nfsd3_diropargs *argp = rqstp->rq_argp;
-	struct nfsd3_attrstat *resp = rqstp->rq_resp;
+	struct RMDIR3args_wrapper *argp = rqstp->rq_argp;
+	struct diropargs3 *object = &argp->xdrgen.object;
+	struct RMDIR3res *resp = rqstp->rq_resp;
+	struct svc_fh *fhp = &argp->fh;
 
-	fh_copy(&resp->fh, &argp->fh);
-	resp->status = nfsd_unlink(rqstp, &resp->fh, S_IFDIR,
-				   argp->name, argp->len);
-	resp->status = nfsd3_map_status(resp->status);
+	nfsd3_fh3_to_svc_fh(fhp, &object->dir);
+	resp->status = nfsd3_check_filename(object->name.data,
+					    object->name.len);
+	if (resp->status != nfs_ok)
+		goto out;
+
+	resp->status = nfsd_unlink(rqstp, fhp, S_IFDIR,
+				   (char *)object->name.data,
+				   object->name.len);
+
+out:
+	if (resp->status == nfs_ok) {
+		nfsd3_fill_wcc_data(rqstp, &resp->u.resok.dir_wcc, fhp);
+	} else {
+		resp->status = nfsd3_map_status(resp->status);
+		nfsd3_fill_wcc_data(rqstp, &resp->u.resfail.dir_wcc, fhp);
+	}
+
+	fh_put(fhp);
 	return rpc_success;
 }
 
@@ -1598,10 +1628,8 @@ nfsd3_proc_commit(struct svc_rqst *rqstp)
  * NFSv3 Server procedures.
  * Only the results of non-idempotent operations are cached.
  */
-#define nfs3svc_encode_wccstatres	nfs3svc_encode_wccstat
 #define nfsd3_readdirplusargs		nfsd3_readdirargs
 #define nfsd3_fhandleargs		nfsd_fhandle
-#define nfsd3_wccstatres		nfsd3_attrstat
 
 #define ST 1		/* status*/
 #define AT 21		/* attributes */
@@ -1756,16 +1784,15 @@ static const struct svc_procedure nfsd_procedures3[22] = {
 		.pc_name	= "REMOVE",
 	},
 	[NFSPROC3_RMDIR] = {
-		.pc_func = nfsd3_proc_rmdir,
-		.pc_decode = nfs3svc_decode_diropargs,
-		.pc_encode = nfs3svc_encode_wccstatres,
-		.pc_release = nfs3svc_release_fhandle,
-		.pc_argsize = sizeof(struct nfsd3_diropargs),
-		.pc_argzero = sizeof(struct nfsd3_diropargs),
-		.pc_ressize = sizeof(struct nfsd3_wccstatres),
-		.pc_cachetype = RC_REPLBUFF,
-		.pc_xdrressize = ST+WC,
-		.pc_name = "RMDIR",
+		.pc_func	= nfsd3_proc_rmdir,
+		.pc_decode	= nfs_svc_decode_RMDIR3args,
+		.pc_encode	= nfs_svc_encode_RMDIR3res,
+		.pc_argsize	= sizeof(struct RMDIR3args_wrapper),
+		.pc_argzero	= 0,
+		.pc_ressize	= sizeof(struct RMDIR3res),
+		.pc_cachetype	= RC_REPLBUFF,
+		.pc_xdrressize	= NFS3_RMDIR3res_sz,
+		.pc_name	= "RMDIR",
 	},
 	[NFSPROC3_RENAME] = {
 		.pc_func = nfsd3_proc_rename,
@@ -1874,7 +1901,6 @@ union nfsd3_xdrstore {
 	struct ACCESS3res		accessres;
 	struct READLINK3args_wrapper	readlinkargs;
 	struct READ3args_wrapper	readargs;
-	struct nfsd3_diropargs		diropargs;
 	struct WRITE3args_wrapper	writeargs;
 	struct CREATE3args_wrapper	createargs;
 	struct CREATE3res_wrapper	createres;
@@ -1886,6 +1912,8 @@ union nfsd3_xdrstore {
 	struct MKNOD3res_wrapper	mknodres;
 	struct REMOVE3args_wrapper	removeargs;
 	struct REMOVE3res		removeres;
+	struct RMDIR3args_wrapper	rmdirargs;
+	struct RMDIR3res		rmdirres;
 	struct nfsd3_renameargs		renameargs;
 	struct nfsd3_linkargs		linkargs;
 	struct nfsd3_readdirargs	readdirargs;
diff --git a/fs/nfsd/nfs3xdr.c b/fs/nfsd/nfs3xdr.c
index 53a82af80ad5..1cfc79724450 100644
--- a/fs/nfsd/nfs3xdr.c
+++ b/fs/nfsd/nfs3xdr.c
@@ -360,14 +360,6 @@ nfs3svc_decode_fhandleargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
 	return svcxdr_decode_nfs_fh3(xdr, &args->fh);
 }
 
-bool
-nfs3svc_decode_diropargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
-{
-	struct nfsd3_diropargs *args = rqstp->rq_argp;
-
-	return svcxdr_decode_diropargs3(xdr, &args->fh, &args->name, &args->len);
-}
-
 bool
 nfs3svc_decode_renameargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
 {
@@ -448,16 +440,6 @@ nfs3svc_decode_commitargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
  * XDR encode functions
  */
 
-/* SETATTR, REMOVE, RMDIR */
-bool
-nfs3svc_encode_wccstat(struct svc_rqst *rqstp, struct xdr_stream *xdr)
-{
-	struct nfsd3_attrstat *resp = rqstp->rq_resp;
-
-	return svcxdr_encode_nfsstat3(xdr, resp->status) &&
-		svcxdr_encode_wcc_data(rqstp, xdr, &resp->fh);
-}
-
 /* RENAME */
 bool
 nfs3svc_encode_renameres(struct svc_rqst *rqstp, struct xdr_stream *xdr)
diff --git a/fs/nfsd/xdr3.h b/fs/nfsd/xdr3.h
index 6d5cea6baf3a..fac60fb4cdf9 100644
--- a/fs/nfsd/xdr3.h
+++ b/fs/nfsd/xdr3.h
@@ -19,12 +19,6 @@
 #define NFS3_MAXNAMLEN			NAME_MAX
 #define NFS3_MAXPATHLEN			PATH_MAX
 
-struct nfsd3_diropargs {
-	struct svc_fh		fh;
-	char *			name;
-	unsigned int		len;
-};
-
 struct nfsd3_accessargs {
 	struct svc_fh		fh;
 	__u32			access;
@@ -171,14 +165,12 @@ struct nfsd3_fhandle_pair {
 };
 
 bool nfs3svc_decode_fhandleargs(struct svc_rqst *rqstp, struct xdr_stream *xdr);
-bool nfs3svc_decode_diropargs(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_wccstat(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);
-- 
2.55.0