+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, ret;
+ loff_t pos = *ppos;
+
+ if (!pos)
+ nfsd_inject_get(file->f_dentry->d_inode->i_private, &val);
+ size = scnprintf(read_buf, sizeof(read_buf), "%llu\n", val);
+
+ if (pos < 0)
+ return -EINVAL;
+ if (pos >= size || !len)
+ return 0;
+ if (len > size - pos)
+ len = size - pos;
+ ret = copy_to_user(buf, read_buf + pos, len);
+ if (ret == len)
+ return -EFAULT;
+ len -= ret;
+ *ppos = pos + len;
+ return len;
+}
+
+static ssize_t fault_inject_write(struct file *file, const char __user *buf,
+ size_t len, loff_t *ppos)
+{
+ char write_buf[24];
+ size_t size = min(sizeof(write_buf), len) - 1;
+ u64 val;
+
+ if (copy_from_user(write_buf, buf, size))
+ return -EFAULT;
+
+ val = simple_strtoll(write_buf, NULL, 0);
+ nfsd_inject_set(file->f_dentry->d_inode->i_private, 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,
+};