[PATCH v10 08/19] nfsd: implement server support for NFS_LOCALIO_PROGRAM

Mike Snitzer
2024-06-30T16:37:54Z

LOCALIOPROC_GETUUID encodes the server's uuid_t in terms of the fixed
UUID_SIZE (16). The fixed size opaque encode and decode XDR methods
are used instead of the less efficient variable sized methods.

Aside from a bit of code in nfssvc.c, all the knowledge of the LOCALIO
RPC protocol is in fs/nfsd/localio.c which implements just a single
version (1) that is used independently of what NFS version is used.

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
[neilb: factored out and simplified single localio protocol]
Co-developed-by: NeilBrown <neil@brown.name>
Signed-off-by: NeilBrown <neil@brown.name>
---
fs/nfsd/localio.c | 74 +++++++++++++++++++++++++++++++++++++++++++++
fs/nfsd/nfssvc.c | 29 +++++++++++++++++-
include/linux/nfs.h | 7 +++++
3 files changed, 109 insertions(+), 1 deletion(-)

diff --git a/fs/nfsd/localio.c b/fs/nfsd/localio.c
index 2e609ada7e19..1d6508aa931e 100644
--- a/fs/nfsd/localio.c
+++ b/fs/nfsd/localio.c
@@ -11,12 +11,15 @@
#include <linux/sunrpc/svcauth_gss.h>
#include <linux/sunrpc/clnt.h>
#include <linux/nfs.h>
+#include <linux/nfs_fs.h>
+#include <linux/nfs_xdr.h>
#include <linux/string.h>

#include "nfsd.h"
#include "vfs.h"
#include "netns.h"
#include "filecache.h"
+#include "cache.h"

/*
* We need to translate between nfs status return values and
@@ -253,3 +256,74 @@ EXPORT_SYMBOL_GPL(nfsd_open_local_fh);

/* Compile time type checking, not used by anything */
static nfs_to_nfsd_open_t __maybe_unused nfsd_open_local_fh_typecheck = nfsd_open_local_fh;
+
+/*
+ * GETUUID XDR encode functions
+ */
+
+static __be32 localio_proc_null(struct svc_rqst *rqstp)
+{
+ return rpc_success;
+}
+
+struct localio_getuuidres {
+ uuid_t uuid;
+};
+
+static __be32 localio_proc_getuuid(struct svc_rqst *rqstp)
+{
+ struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
+ struct localio_getuuidres *resp = rqstp->rq_resp;
+
+ uuid_copy(&resp->uuid, &nn->nfsd_uuid.uuid);
+
+ return rpc_success;
+}
+
+static bool localio_encode_getuuidres(struct svc_rqst *rqstp,
+ struct xdr_stream *xdr)
+{
+ struct localio_getuuidres *resp = rqstp->rq_resp;
+ u8 uuid[UUID_SIZE];
+
+ export_uuid(uuid, &resp->uuid);
+ encode_opaque_fixed(xdr, uuid, UUID_SIZE);
+
+ return true;
+}
+
+static const struct svc_procedure localio_procedures1[] = {
+ [LOCALIOPROC_NULL] = {
+ .pc_func = localio_proc_null,
+ .pc_decode = nfssvc_decode_voidarg,
+ .pc_encode = nfssvc_encode_voidres,
+ .pc_argsize = sizeof(struct nfsd_voidargs),
+ .pc_ressize = sizeof(struct nfsd_voidres),
+ .pc_cachetype = RC_NOCACHE,
+ .pc_xdrressize = 0,
+ .pc_name = "NULL",
+ },
+ [LOCALIOPROC_GETUUID] = {
+ .pc_func = localio_proc_getuuid,
+ .pc_decode = nfssvc_decode_voidarg,
+ .pc_encode = localio_encode_getuuidres,
+ .pc_argsize = sizeof(struct nfsd_voidargs),
+ .pc_ressize = sizeof(struct localio_getuuidres),
+ .pc_cachetype = RC_NOCACHE,
+ .pc_xdrressize = XDR_QUADLEN(UUID_SIZE),
+ .pc_name = "GETUUID",
+ },
+};
+
+#define LOCALIO_NR_PROCEDURES ARRAY_SIZE(localio_procedures1)
+static DEFINE_PER_CPU_ALIGNED(unsigned long,
+ localio_count[LOCALIO_NR_PROCEDURES]);
+const struct svc_version localio_version1 = {
+ .vs_vers = 1,
+ .vs_nproc = LOCALIO_NR_PROCEDURES,
+ .vs_proc = localio_procedures1,
+ .vs_dispatch = nfsd_dispatch,
+ .vs_count = localio_count,
+ .vs_xdrsize = XDR_QUADLEN(UUID_SIZE),
+ .vs_hidden = true,
+};
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index 90922c0586d5..3e528d242966 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -81,6 +81,26 @@ DEFINE_SPINLOCK(nfsd_drc_lock);
unsigned long nfsd_drc_max_mem;
unsigned long nfsd_drc_mem_used;

+#if IS_ENABLED(CONFIG_NFSD_LOCALIO)
+extern const struct svc_version localio_version1;
+static const struct svc_version *localio_versions[] = {
+ [1] = &localio_version1,
+};
+
+#define NFSD_LOCALIO_NRVERS ARRAY_SIZE(localio_versions)
+
+static struct svc_program nfsd_localio_program = {
+ .pg_prog = NFS_LOCALIO_PROGRAM,
+ .pg_nvers = NFSD_LOCALIO_NRVERS,
+ .pg_vers = localio_versions,
+ .pg_name = "nfslocalio",
+ .pg_class = "nfsd",
+ .pg_authenticate = &svc_set_client,
+ .pg_init_request = svc_generic_init_request,
+ .pg_rpcbind_set = svc_generic_rpcbind_set,
+};
+#endif /* CONFIG_NFSD_LOCALIO */
+
#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
static const struct svc_version *nfsd_acl_version[] = {
# if defined(CONFIG_NFSD_V2_ACL)
@@ -95,6 +115,9 @@ static const struct svc_version *nfsd_acl_version[] = {
#define NFSD_ACL_NRVERS ARRAY_SIZE(nfsd_acl_version)

static struct svc_program nfsd_acl_program = {
+#if IS_ENABLED(CONFIG_NFSD_LOCALIO)
+ .pg_next = &nfsd_localio_program,
+#endif /* CONFIG_NFSD_LOCALIO */
.pg_prog = NFS_ACL_PROGRAM,
.pg_nvers = NFSD_ACL_NRVERS,
.pg_vers = nfsd_acl_version,
@@ -123,6 +146,10 @@ static const struct svc_version *nfsd_version[] = {
struct svc_program nfsd_program = {
#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
.pg_next = &nfsd_acl_program,
+#else
+#if IS_ENABLED(CONFIG_NFSD_LOCALIO)
+ .pg_next = &nfsd_localio_program,
+#endif /* CONFIG_NFSD_LOCALIO */
#endif
.pg_prog = NFS_PROGRAM, /* program number */
.pg_nvers = NFSD_NRVERS, /* nr of entries in nfsd_version */
@@ -1020,7 +1047,7 @@ nfsd(void *vrqstp)
}

/**
- * nfsd_dispatch - Process an NFS or NFSACL Request
+ * nfsd_dispatch - Process an NFS or NFSACL or LOCALIO Request
* @rqstp: incoming request
*
* This RPC dispatcher integrates the NFS server's duplicate reply cache.
diff --git a/include/linux/nfs.h b/include/linux/nfs.h
index ceb70a926b95..b1e00349f3ed 100644
--- a/include/linux/nfs.h
+++ b/include/linux/nfs.h
@@ -13,6 +13,13 @@
#include <linux/crc32.h>
#include <uapi/linux/nfs.h>

+/* The localio program is entirely private to Linux and is
+ * NOT part of the uapi.
+ */
+#define NFS_LOCALIO_PROGRAM 400122
+#define LOCALIOPROC_NULL 0
+#define LOCALIOPROC_GETUUID 1
+
/*
* This is the kernel NFS client file handle representation
*/
--
2.44.0