NFS: Fix nfsstat breakage due to LOOKUPP

The LOOKUPP operation was inserted into the nfs4_procedures array
rather than being appended, which put /proc/net/rpc/nfs out of
whack, and broke the nfsstat utility.
Fix by moving the LOOKUPP operation to the end of the array, and
by ensuring that it keeps the same length whether or not NFSV4.1
and NFSv4.2 are compiled in.

Fixes: 5b5faaf ("nfs4: add NFSv4 LOOKUPP handlers")
Cc: stable@vger.kernel.org # v4.13+
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

fs/nfs/nfs4xdr.c

@@ -7678,6 +7678,22 @@ nfs4_stat_to_errno(int stat)
 	.p_name = #proc,	\
 }
 
+#if defined(CONFIG_NFS_V4_1)
+#define PROC41(proc, argtype, restype)				\
+	PROC(proc, argtype, restype)
+#else
+#define PROC41(proc, argtype, restype)				\
+	STUB(proc)
+#endif
+
+#if defined(CONFIG_NFS_V4_2)
+#define PROC42(proc, argtype, restype)				\
+	PROC(proc, argtype, restype)
+#else
+#define PROC42(proc, argtype, restype)				\
+	STUB(proc)
+#endif
+
 const struct rpc_procinfo nfs4_procedures[] = {
 	PROC(READ,		enc_read,		dec_read),
 	PROC(WRITE,		enc_write,		dec_write),
@@ -7698,7 +7714,6 @@ const struct rpc_procinfo nfs4_procedures[] = {
 	PROC(ACCESS,		enc_access,		dec_access),
 	PROC(GETATTR,		enc_getattr,		dec_getattr),
 	PROC(LOOKUP,		enc_lookup,		dec_lookup),
-	PROC(LOOKUPP,		enc_lookupp,		dec_lookupp),
 	PROC(LOOKUP_ROOT,	enc_lookup_root,	dec_lookup_root),
 	PROC(REMOVE,		enc_remove,		dec_remove),
 	PROC(RENAME,		enc_rename,		dec_rename),
@@ -7717,33 +7732,30 @@ const struct rpc_procinfo nfs4_procedures[] = {
 	PROC(RELEASE_LOCKOWNER,	enc_release_lockowner,	dec_release_lockowner),
 	PROC(SECINFO,		enc_secinfo,		dec_secinfo),
 	PROC(FSID_PRESENT,	enc_fsid_present,	dec_fsid_present),
-#if defined(CONFIG_NFS_V4_1)
-	PROC(EXCHANGE_ID,	enc_exchange_id,	dec_exchange_id),
-	PROC(CREATE_SESSION,	enc_create_session,	dec_create_session),
-	PROC(DESTROY_SESSION,	enc_destroy_session,	dec_destroy_session),
-	PROC(SEQUENCE,		enc_sequence,		dec_sequence),
-	PROC(GET_LEASE_TIME,	enc_get_lease_time,	dec_get_lease_time),
-	PROC(RECLAIM_COMPLETE,	enc_reclaim_complete,	dec_reclaim_complete),
-	PROC(GETDEVICEINFO,	enc_getdeviceinfo,	dec_getdeviceinfo),
-	PROC(LAYOUTGET,		enc_layoutget,		dec_layoutget),
-	PROC(LAYOUTCOMMIT,	enc_layoutcommit,	dec_layoutcommit),
-	PROC(LAYOUTRETURN,	enc_layoutreturn,	dec_layoutreturn),
-	PROC(SECINFO_NO_NAME,	enc_secinfo_no_name,	dec_secinfo_no_name),
-	PROC(TEST_STATEID,	enc_test_stateid,	dec_test_stateid),
-	PROC(FREE_STATEID,	enc_free_stateid,	dec_free_stateid),
+	PROC41(EXCHANGE_ID,	enc_exchange_id,	dec_exchange_id),
+	PROC41(CREATE_SESSION,	enc_create_session,	dec_create_session),
+	PROC41(DESTROY_SESSION,	enc_destroy_session,	dec_destroy_session),
+	PROC41(SEQUENCE,	enc_sequence,		dec_sequence),
+	PROC41(GET_LEASE_TIME,	enc_get_lease_time,	dec_get_lease_time),
+	PROC41(RECLAIM_COMPLETE,enc_reclaim_complete,	dec_reclaim_complete),
+	PROC41(GETDEVICEINFO,	enc_getdeviceinfo,	dec_getdeviceinfo),
+	PROC41(LAYOUTGET,	enc_layoutget,		dec_layoutget),
+	PROC41(LAYOUTCOMMIT,	enc_layoutcommit,	dec_layoutcommit),
+	PROC41(LAYOUTRETURN,	enc_layoutreturn,	dec_layoutreturn),
+	PROC41(SECINFO_NO_NAME,	enc_secinfo_no_name,	dec_secinfo_no_name),
+	PROC41(TEST_STATEID,	enc_test_stateid,	dec_test_stateid),
+	PROC41(FREE_STATEID,	enc_free_stateid,	dec_free_stateid),
 	STUB(GETDEVICELIST),
-	PROC(BIND_CONN_TO_SESSION,
+	PROC41(BIND_CONN_TO_SESSION,
 			enc_bind_conn_to_session, dec_bind_conn_to_session),
-	PROC(DESTROY_CLIENTID,	enc_destroy_clientid,	dec_destroy_clientid),
-#endif /* CONFIG_NFS_V4_1 */
-#ifdef CONFIG_NFS_V4_2
-	PROC(SEEK,		enc_seek,		dec_seek),
-	PROC(ALLOCATE,		enc_allocate,		dec_allocate),
-	PROC(DEALLOCATE,	enc_deallocate,		dec_deallocate),
-	PROC(LAYOUTSTATS,	enc_layoutstats,	dec_layoutstats),
-	PROC(CLONE,		enc_clone,		dec_clone),
-	PROC(COPY,		enc_copy,		dec_copy),
-#endif /* CONFIG_NFS_V4_2 */
+	PROC41(DESTROY_CLIENTID,enc_destroy_clientid,	dec_destroy_clientid),
+	PROC42(SEEK,		enc_seek,		dec_seek),
+	PROC42(ALLOCATE,	enc_allocate,		dec_allocate),
+	PROC42(DEALLOCATE,	enc_deallocate,		dec_deallocate),
+	PROC42(LAYOUTSTATS,	enc_layoutstats,	dec_layoutstats),
+	PROC42(CLONE,		enc_clone,		dec_clone),
+	PROC42(COPY,		enc_copy,		dec_copy),
+	PROC(LOOKUPP,		enc_lookupp,		dec_lookupp),
 };
 
 static unsigned int nfs_version4_counts[ARRAY_SIZE(nfs4_procedures)];

include/linux/nfs4.h

@@ -457,7 +457,12 @@ enum lock_type4 {
 
 #define NFS4_DEBUG 1
 
-/* Index of predefined Linux client operations */
+/*
+ * Index of predefined Linux client operations
+ *
+ * To ensure that /proc/net/rpc/nfs remains correctly ordered, please
+ * append only to this enum when adding new client operations.
+ */
 
 enum {
 	NFSPROC4_CLNT_NULL = 0,		/* Unused */
@@ -480,7 +485,6 @@ enum {
 	NFSPROC4_CLNT_ACCESS,
 	NFSPROC4_CLNT_GETATTR,
 	NFSPROC4_CLNT_LOOKUP,
-	NFSPROC4_CLNT_LOOKUPP,
 	NFSPROC4_CLNT_LOOKUP_ROOT,
 	NFSPROC4_CLNT_REMOVE,
 	NFSPROC4_CLNT_RENAME,
@@ -500,7 +504,6 @@ enum {
 	NFSPROC4_CLNT_SECINFO,
 	NFSPROC4_CLNT_FSID_PRESENT,
 
-	/* nfs41 */
 	NFSPROC4_CLNT_EXCHANGE_ID,
 	NFSPROC4_CLNT_CREATE_SESSION,
 	NFSPROC4_CLNT_DESTROY_SESSION,
@@ -518,13 +521,14 @@ enum {
 	NFSPROC4_CLNT_BIND_CONN_TO_SESSION,
 	NFSPROC4_CLNT_DESTROY_CLIENTID,
 
-	/* nfs42 */
 	NFSPROC4_CLNT_SEEK,
 	NFSPROC4_CLNT_ALLOCATE,
 	NFSPROC4_CLNT_DEALLOCATE,
 	NFSPROC4_CLNT_LAYOUTSTATS,
 	NFSPROC4_CLNT_CLONE,
 	NFSPROC4_CLNT_COPY,
+
+	NFSPROC4_CLNT_LOOKUPP,
 };
 
 /* nfs41 types */