/*
   * Copyright (c) 2011 Bryan Schumaker <bjschuma@netapp.com>
   *
   * Uses debugfs to create fault injection points for client testing
   */
  
  #include <linux/types.h>
  #include <linux/fs.h>
  #include <linux/debugfs.h>
  #include <linux/module.h>

  #include <linux/nsproxy.h>

  #include <linux/sunrpc/addr.h>

  #include <asm/uaccess.h>

  
  #include "state.h"

  #include "netns.h"

  
  struct nfsd_fault_inject_op {
  	char *file;

  	u64 (*get)(void);
  	u64 (*set_val)(u64);
  	u64 (*set_clnt)(struct sockaddr_storage *, size_t);

  };

  static struct dentry *debug_dir;

  static ssize_t fault_inject_read(struct file *file, char __user *buf,
  				 size_t len, loff_t *ppos)
  {
  	static u64 val;
  	char read_buf[25];

  	size_t size;

  	loff_t pos = *ppos;

  	struct nfsd_fault_inject_op *op = file_inode(file)->i_private;

  
  	if (!pos)

  		val = op->get();

  	size = scnprintf(read_buf, sizeof(read_buf), "%llu
  ", val);

  	return simple_read_from_buffer(buf, len, ppos, read_buf, size);

  }
  
  static ssize_t fault_inject_write(struct file *file, const char __user *buf,
  				  size_t len, loff_t *ppos)
  {

  	char write_buf[INET6_ADDRSTRLEN];

  	size_t size = min(sizeof(write_buf) - 1, len);

  	struct net *net = current->nsproxy->net_ns;
  	struct sockaddr_storage sa;

  	struct nfsd_fault_inject_op *op = file_inode(file)->i_private;

  	u64 val;

  	char *nl;

  
  	if (copy_from_user(write_buf, buf, size))
  		return -EFAULT;

  	write_buf[size] = '\0';

  	/* Deal with any embedded newlines in the string */
  	nl = strchr(write_buf, '
  ');
  	if (nl) {
  		size = nl - write_buf;
  		*nl = '\0';
  	}

  	size = rpc_pton(net, write_buf, size, (struct sockaddr *)&sa, sizeof(sa));

  	if (size > 0) {

  		val = op->set_clnt(&sa, size);

  		if (val)
  			pr_info("NFSD [%s]: Client %s had %llu state object(s)
  ",
  				op->file, write_buf, val);
  	} else {

  		val = simple_strtoll(write_buf, NULL, 0);

  		if (val == 0)
  			pr_info("NFSD Fault Injection: %s (all)", op->file);
  		else
  			pr_info("NFSD Fault Injection: %s (n = %llu)",
  				op->file, val);

  		val = op->set_val(val);

  		pr_info("NFSD: %s: found %llu", op->file, val);

  	}

  	return len; /* on success, claim we got the whole input */
  }
  
  static const struct file_operations fops_nfsd = {
  	.owner   = THIS_MODULE,
  	.read    = fault_inject_read,
  	.write   = fault_inject_write,
  };

  
  void nfsd_fault_inject_cleanup(void)
  {
  	debugfs_remove_recursive(debug_dir);
  }

  static struct nfsd_fault_inject_op inject_ops[] = {
  	{
  		.file     = "forget_clients",

  		.get	  = nfsd_inject_print_clients,

  		.set_val  = nfsd_inject_forget_clients,

  		.set_clnt = nfsd_inject_forget_client,

  	},
  	{
  		.file     = "forget_locks",

  		.get	  = nfsd_inject_print_locks,
  		.set_val  = nfsd_inject_forget_locks,
  		.set_clnt = nfsd_inject_forget_client_locks,

  	},
  	{
  		.file     = "forget_openowners",

  		.get	  = nfsd_inject_print_openowners,
  		.set_val  = nfsd_inject_forget_openowners,
  		.set_clnt = nfsd_inject_forget_client_openowners,

  	},
  	{
  		.file     = "forget_delegations",

  		.get	  = nfsd_inject_print_delegations,
  		.set_val  = nfsd_inject_forget_delegations,
  		.set_clnt = nfsd_inject_forget_client_delegations,

  	},
  	{
  		.file     = "recall_delegations",

  		.get	  = nfsd_inject_print_delegations,
  		.set_val  = nfsd_inject_recall_delegations,
  		.set_clnt = nfsd_inject_recall_client_delegations,

  	},
  };
  
  #define NUM_INJECT_OPS (sizeof(inject_ops)/sizeof(struct nfsd_fault_inject_op))

  int nfsd_fault_inject_init(void)
  {
  	unsigned int i;
  	struct nfsd_fault_inject_op *op;

  	umode_t mode = S_IFREG | S_IRUSR | S_IWUSR;

  
  	debug_dir = debugfs_create_dir("nfsd", NULL);
  	if (!debug_dir)
  		goto fail;
  
  	for (i = 0; i < NUM_INJECT_OPS; i++) {
  		op = &inject_ops[i];
  		if (!debugfs_create_file(op->file, mode, debug_dir, op, &fops_nfsd))
  			goto fail;
  	}
  	return 0;
  
  fail:
  	nfsd_fault_inject_cleanup();
  	return -ENOMEM;
  }