fs/nfsd/fault_inject.c

   1 /*
   2  * Copyright (c) 2011 Bryan Schumaker <bjschuma@netapp.com>
   3  *
   4  * Uses debugfs to create fault injection points for client testing
   5  */
   6
   7 #include <linux/types.h>
   8 #include <linux/fs.h>
   9 #include <linux/debugfs.h>
  10 #include <linux/module.h>
  11 #include <asm/uaccess.h>
  12
  13 #include "state.h"
  14
  15 struct nfsd_fault_inject_op {
  16         char *file;
  17         u64 (*forget)(struct nfs4_client *, u64);
  18         u64 (*print)(struct nfs4_client *, u64);
  19 };
  20
  21 static struct nfsd_fault_inject_op inject_ops[] = {
  22         {
  23                 .file   = "forget_clients",
  24                 .forget = nfsd_forget_client,
  25                 .print  = nfsd_print_client,
  26         },
  27         {
  28                 .file   = "forget_locks",
  29                 .forget = nfsd_forget_client_locks,
  30                 .print  = nfsd_print_client_locks,
  31         },
  32         {
  33                 .file   = "forget_openowners",
  34                 .forget = nfsd_forget_client_openowners,
  35                 .print  = nfsd_print_client_openowners,
  36         },
  37         {
  38                 .file   = "forget_delegations",
  39                 .forget = nfsd_forget_client_delegations,
  40                 .print  = nfsd_print_client_delegations,
  41         },
  42         {
  43                 .file   = "recall_delegations",
  44                 .forget = nfsd_recall_client_delegations,
  45                 .print  = nfsd_print_client_delegations,
  46         },
  47 };
  48
  49 static long int NUM_INJECT_OPS = sizeof(inject_ops) / sizeof(struct nfsd_fault_inject_op);
  50 static struct dentry *debug_dir;
  51
  52 static void nfsd_inject_set(struct nfsd_fault_inject_op *op, u64 val)
  53 {
  54         u64 count = 0;
  55
  56         if (val == 0)
  57                 printk(KERN_INFO "NFSD Fault Injection: %s (all)", op->file);
  58         else
  59                 printk(KERN_INFO "NFSD Fault Injection: %s (n = %llu)", op->file, val);
  60
  61         nfs4_lock_state();
  62         count = nfsd_for_n_state(val, op->forget);
  63         nfs4_unlock_state();
  64         printk(KERN_INFO "NFSD: %s: found %llu", op->file, count);
  65 }
  66
  67 static void nfsd_inject_get(struct nfsd_fault_inject_op *op, u64 *val)
  68 {
  69         nfs4_lock_state();
  70         *val = nfsd_for_n_state(0, op->print);
  71         nfs4_unlock_state();
  72 }
  73
  74 static ssize_t fault_inject_read(struct file *file, char __user *buf,
  75                                  size_t len, loff_t *ppos)
  76 {
  77         static u64 val;
  78         char read_buf[25];
  79         size_t size, ret;
  80         loff_t pos = *ppos;
  81
  82         if (!pos)
  83                 nfsd_inject_get(file->f_dentry->d_inode->i_private, &val);
  84         size = scnprintf(read_buf, sizeof(read_buf), "%llu\n", val);
  85
  86         if (pos < 0)
  87                 return -EINVAL;
  88         if (pos >= size || !len)
  89                 return 0;
  90         if (len > size - pos)
  91                 len = size - pos;
  92         ret = copy_to_user(buf, read_buf + pos, len);
  93         if (ret == len)
  94                 return -EFAULT;
  95         len -= ret;
  96         *ppos = pos + len;
  97         return len;
  98 }
  99
 100 static ssize_t fault_inject_write(struct file *file, const char __user *buf,
 101                                   size_t len, loff_t *ppos)
 102 {
 103         char write_buf[24];
 104         size_t size = min(sizeof(write_buf), len) - 1;
 105         u64 val;
 106
 107         if (copy_from_user(write_buf, buf, size))
 108                 return -EFAULT;
 109
 110         val = simple_strtoll(write_buf, NULL, 0);
 111         nfsd_inject_set(file->f_dentry->d_inode->i_private, val);
 112         return len; /* on success, claim we got the whole input */
 113 }
 114
 115 static const struct file_operations fops_nfsd = {
 116         .owner   = THIS_MODULE,
 117         .read    = fault_inject_read,
 118         .write   = fault_inject_write,
 119 };
 120
 121 void nfsd_fault_inject_cleanup(void)
 122 {
 123         debugfs_remove_recursive(debug_dir);
 124 }
 125
 126 int nfsd_fault_inject_init(void)
 127 {
 128         unsigned int i;
 129         struct nfsd_fault_inject_op *op;
 130         umode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
 131
 132         debug_dir = debugfs_create_dir("nfsd", NULL);
 133         if (!debug_dir)
 134                 goto fail;
 135
 136         for (i = 0; i < NUM_INJECT_OPS; i++) {
 137                 op = &inject_ops[i];
 138                 if (!debugfs_create_file(op->file, mode, debug_dir, op, &fops_nfsd))
 139                         goto fail;
 140         }
 141         return 0;
 142
 143 fail:
 144         nfsd_fault_inject_cleanup();
 145         return -ENOMEM;
 146 }