[PATCH v1 17/27] NFSD: Use xdrgen XDR functions for the NFSv2 REMOVE procedure

[Chuck Lever <cel@kernel.org>]

Replace the NFSPROC_REMOVE entry in the nfsd_procedures2 array
with an entry that dispatches the xdrgen-generated
nfs_svc_decode_diropargs and nfs_svc_encode_nfsstat. A wrapper
structure bridges the generated xdrgen diropargs type and the
legacy svc_fh representation the NFSD VFS layer still uses.

The pc_argzero field is now set to zero for the NFSv2 REMOVE
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.

The hand-coded nfssvc_decode_diropargs and nfssvc_encode_statres
remain for the procedures that still use them.

Signed-off-by: Chuck Lever <cel@kernel.org>
---
 fs/nfsd/nfsproc.c | 50 ++++++++++++++++++++++++++++++-----------------
 1 file changed, 32 insertions(+), 18 deletions(-)

diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c
index 69dcd482b77f..ae74247a892f 100644
--- a/fs/nfsd/nfsproc.c
+++ b/fs/nfsd/nfsproc.c
@@ -847,17 +847,31 @@ static __be32 nfsd_proc_create(struct svc_rqst *rqstp)
 	return rpc_success;
 }
 
-static __be32
-nfsd_proc_remove(struct svc_rqst *rqstp)
+/**
+ * nfsd_proc_remove - REMOVE: Remove a file
+ * @rqstp: RPC transaction context
+ *
+ * Return:
+ *   %rpc_success:		RPC executed successfully
+ *
+ * RPC synopsis:
+ *   nfsstat NFSPROC_REMOVE(diropargs) = 10;
+ */
+static __be32 nfsd_proc_remove(struct svc_rqst *rqstp)
 {
-	struct nfsd_diropargs *argp = rqstp->rq_argp;
-	struct nfsd_stat *resp = rqstp->rq_resp;
+	struct diropargs_wrapper *argp = rqstp->rq_argp;
+	struct diropargs *object = &argp->xdrgen;
+	nfsstat *resp = rqstp->rq_resp;
+	struct svc_fh *fhp = &argp->fh;
 
-	/* Unlink. -SIFDIR means file must not be a directory */
-	resp->status = nfsd_unlink(rqstp, &argp->fh, -S_IFDIR,
-				   argp->name, argp->len);
-	fh_put(&argp->fh);
-	resp->status = nfsd_map_status(resp->status);
+	nfsd_fhandle_to_svc_fh(fhp, &object->dir);
+
+	/* Unlink. -S_IFDIR means file must not be a directory */
+	*resp = nfsd_unlink(rqstp, fhp, -S_IFDIR,
+			    (char *)object->name.data, object->name.len);
+	*resp = nfsd_map_status(*resp);
+
+	fh_put(fhp);
 	return rpc_success;
 }
 
@@ -1153,15 +1167,15 @@ static const struct svc_procedure nfsd_procedures2[18] = {
 		.pc_name	= "CREATE",
 	},
 	[NFSPROC_REMOVE] = {
-		.pc_func = nfsd_proc_remove,
-		.pc_decode = nfssvc_decode_diropargs,
-		.pc_encode = nfssvc_encode_statres,
-		.pc_argsize = sizeof(struct nfsd_diropargs),
-		.pc_argzero = sizeof(struct nfsd_diropargs),
-		.pc_ressize = sizeof(struct nfsd_stat),
-		.pc_cachetype = RC_REPLSTAT,
-		.pc_xdrressize = ST,
-		.pc_name = "REMOVE",
+		.pc_func	= nfsd_proc_remove,
+		.pc_decode	= nfs_svc_decode_diropargs,
+		.pc_encode	= nfs_svc_encode_nfsstat,
+		.pc_argsize	= sizeof(struct diropargs_wrapper),
+		.pc_argzero	= 0,
+		.pc_ressize	= sizeof(nfsstat),
+		.pc_cachetype	= RC_REPLSTAT,
+		.pc_xdrressize	= NFS2_nfsstat_sz,
+		.pc_name	= "REMOVE",
 	},
 	[NFSPROC_RENAME] = {
 		.pc_func = nfsd_proc_rename,
-- 
2.55.0