nfsd: remove fault injection code

It was an interesting idea but nobody seems to be using it, it's buggy
at this point, and nfs4state.c is already complicated enough without it.
The new nfsd/clients/ code provides some of the same functionality, and
could probably do more if desired.

This feature has been deprecated since 9d60d931 ("Deprecate nfsd
fault injection").
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Documentation/admin-guide/nfs/fault_injection.rst

-===================
-NFS Fault Injection
-===================
-
-Fault injection is a method for forcing errors that may not normally occur, or
-may be difficult to reproduce.  Forcing these errors in a controlled environment
-can help the developer find and fix bugs before their code is shipped in a
-production system.  Injecting an error on the Linux NFS server will allow us to
-observe how the client reacts and if it manages to recover its state correctly.
-
-NFSD_FAULT_INJECTION must be selected when configuring the kernel to use this
-feature.
-
-
-Using Fault Injection
-=====================
-On the client, mount the fault injection server through NFS v4.0+ and do some
-work over NFS (open files, take locks, ...).
-
-On the server, mount the debugfs filesystem to <debug_dir> and ls
-<debug_dir>/nfsd.  This will show a list of files that will be used for
-injecting faults on the NFS server.  As root, write a number n to the file
-corresponding to the action you want the server to take.  The server will then
-process the first n items it finds.  So if you want to forget 5 locks, echo '5'
-to <debug_dir>/nfsd/forget_locks.  A value of 0 will tell the server to forget
-all corresponding items.  A log message will be created containing the number
-of items forgotten (check dmesg).
-
-Go back to work on the client and check if the client recovered from the error
-correctly.
-
-
-Available Faults
-================
-forget_clients:
-     The NFS server keeps a list of clients that have placed a mount call.  If
-     this list is cleared, the server will have no knowledge of who the client
-     is, forcing the client to reauthenticate with the server.
-
-forget_openowners:
-     The NFS server keeps a list of what files are currently opened and who
-     they were opened by.  Clearing this list will force the client to reopen
-     its files.
-
-forget_locks:
-     The NFS server keeps a list of what files are currently locked in the VFS.
-     Clearing this list will force the client to reclaim its locks (files are
-     unlocked through the VFS as they are cleared from this list).
-
-forget_delegations:
-     A delegation is used to assure the client that a file, or part of a file,
-     has not changed since the delegation was awarded.  Clearing this list will
-     force the client to reacquire its delegation before accessing the file
-     again.
-
-recall_delegations:
-     Delegations can be recalled by the server when another client attempts to
-     access a file.  This test will notify the client that its delegation has
-     been revoked, forcing the client to reacquire the delegation before using
-     the file again.
-
-
-tools/nfs/inject_faults.sh script
-=================================
-This script has been created to ease the fault injection process.  This script
-will detect the mounted debugfs directory and write to the files located there
-based on the arguments passed by the user.  For example, running
-`inject_faults.sh forget_locks 1` as root will instruct the server to forget
-one lock.  Running `inject_faults forget_locks` will instruct the server to
-forgetall locks.

Documentation/admin-guide/nfs/index.rst

@@ -12,4 +12,3 @@ NFS
     nfs-idmapper
     pnfs-block-server
     pnfs-scsi-server
-    fault_injection

fs/nfsd/Kconfig

@@ -156,13 +156,3 @@ config NFSD_V4_SECURITY_LABEL
 
 	If you do not wish to enable fine-grained security labels SELinux or
 	Smack policies on NFSv4 files, say N.
-
-config NFSD_FAULT_INJECTION
-	bool "NFS server manual fault injection"
-	depends on NFSD_V4 && DEBUG_KERNEL && DEBUG_FS && BROKEN
-	help
-	  This option enables support for manually injecting faults
-	  into the NFS server.  This is intended to be used for
-	  testing error recovery on the NFS client.
-
-	  If unsure, say N.

fs/nfsd/Makefile

@@ -13,7 +13,6 @@ nfsd-y			+= trace.o
 nfsd-y 			+= nfssvc.o nfsctl.o nfsproc.o nfsfh.o vfs.o \
 			   export.o auth.o lockd.o nfscache.o nfsxdr.o \
 			   stats.o filecache.o
-nfsd-$(CONFIG_NFSD_FAULT_INJECTION) += fault_inject.o
 nfsd-$(CONFIG_NFSD_V2_ACL) += nfs2acl.o
 nfsd-$(CONFIG_NFSD_V3)	+= nfs3proc.o nfs3xdr.o
 nfsd-$(CONFIG_NFSD_V3_ACL) += nfs3acl.o

fs/nfsd/nfsctl.c

@@ -1534,7 +1534,6 @@ static int __init init_nfsd(void)
 	retval = nfsd4_init_pnfs();
 	if (retval)
 		goto out_free_slabs;
-	nfsd_fault_inject_init(); /* nfsd fault injection controls */
 	nfsd_stat_init();	/* Statistics */
 	retval = nfsd_drc_slab_create();
 	if (retval)
@@ -1555,7 +1554,6 @@ static int __init init_nfsd(void)
 	nfsd_drc_slab_free();
 out_free_stat:
 	nfsd_stat_shutdown();
-	nfsd_fault_inject_cleanup();
 	nfsd4_exit_pnfs();
 out_free_slabs:
 	nfsd4_free_slabs();
@@ -1575,7 +1573,6 @@ static void __exit exit_nfsd(void)
 	nfsd_lockd_shutdown();
 	nfsd4_free_slabs();
 	nfsd4_exit_pnfs();
-	nfsd_fault_inject_cleanup();
 	unregister_filesystem(&nfsd_fs_type);
 	unregister_cld_notifier();
 	unregister_pernet_subsys(&nfsd_net_ops);

fs/nfsd/state.h

@@ -693,31 +693,4 @@ extern void nfsd4_client_record_remove(struct nfs4_client *clp);
 extern int nfsd4_client_record_check(struct nfs4_client *clp);
 extern void nfsd4_record_grace_done(struct nfsd_net *nn);
 
-/* nfs fault injection functions */
-#ifdef CONFIG_NFSD_FAULT_INJECTION
-void nfsd_fault_inject_init(void);
-void nfsd_fault_inject_cleanup(void);
-
-u64 nfsd_inject_print_clients(void);
-u64 nfsd_inject_forget_client(struct sockaddr_storage *, size_t);
-u64 nfsd_inject_forget_clients(u64);
-
-u64 nfsd_inject_print_locks(void);
-u64 nfsd_inject_forget_client_locks(struct sockaddr_storage *, size_t);
-u64 nfsd_inject_forget_locks(u64);
-
-u64 nfsd_inject_print_openowners(void);
-u64 nfsd_inject_forget_client_openowners(struct sockaddr_storage *, size_t);
-u64 nfsd_inject_forget_openowners(u64);
-
-u64 nfsd_inject_print_delegations(void);
-u64 nfsd_inject_forget_client_delegations(struct sockaddr_storage *, size_t);
-u64 nfsd_inject_forget_delegations(u64);
-u64 nfsd_inject_recall_client_delegations(struct sockaddr_storage *, size_t);
-u64 nfsd_inject_recall_delegations(u64);
-#else /* CONFIG_NFSD_FAULT_INJECTION */
-static inline void nfsd_fault_inject_init(void) {}
-static inline void nfsd_fault_inject_cleanup(void) {}
-#endif /* CONFIG_NFSD_FAULT_INJECTION */
-
 #endif   /* NFSD4_STATE_H */

tools/nfsd/inject_fault.sh

-#!/bin/bash
-# SPDX-License-Identifier: GPL-2.0
-#
-# Copyright (c) 2011 Bryan Schumaker <bjschuma@netapp.com>
-#
-# Script for easier NFSD fault injection
-
-# Check that debugfs has been mounted
-DEBUGFS=`cat /proc/mounts | grep debugfs`
-if [ "$DEBUGFS" == "" ]; then
-	echo "debugfs does not appear to be mounted!"
-	echo "Please mount debugfs and try again"
-	exit 1
-fi
-
-# Check that the fault injection directory exists
-DEBUGDIR=`echo $DEBUGFS | awk '{print $2}'`/nfsd
-if [ ! -d "$DEBUGDIR" ]; then
-	echo "$DEBUGDIR does not exist"
-	echo "Check that your .config selects CONFIG_NFSD_FAULT_INJECTION"
-	exit 1
-fi
-
-function help()
-{
-	echo "Usage $0 injection_type [count]"
-	echo ""
-	echo "Injection types are:"
-	ls $DEBUGDIR
-	exit 1
-}
-
-if [ $# == 0 ]; then
-	help
-elif [ ! -f $DEBUGDIR/$1 ]; then
-	help
-elif [ $# != 2 ]; then
-	COUNT=0
-else
-	COUNT=$2
-fi
-
-BEFORE=`mktemp`
-AFTER=`mktemp`
-dmesg > $BEFORE
-echo $COUNT > $DEBUGDIR/$1
-dmesg > $AFTER
-# Capture lines that only exist in the $AFTER file
-diff $BEFORE $AFTER | grep ">"
-rm -f $BEFORE $AFTER