linux 1.0 内核注解 linux/fs/ext2/ioctl.c

taozhijiangscu

/********************************************
*Created By: Prometheus
*Date        : 2009-5-29   
********************************************/
/*
* linux/fs/ext2/ioctl.c
*
* Copyright (C) 1993, 1994  Remy Card (
card@masi.ibp.fr
)
*                           Laboratoire MASI - Institut Blaise Pascal
*                           Universite Pierre et Marie Curie (Paris VI)
*/
#include
#include
#include
#include
#include
#include
//很少，就是对节点的标记和版本进行设置操作
//是调用了VFS后面的联合进行特定文件系统的操作的
int ext2_ioctl (struct inode * inode, struct file * filp, unsigned int cmd,
  unsigned long arg)
{
ext2_debug ("cmd = %u, arg = %lu\n", cmd, arg);
switch (cmd) {
case EXT2_IOC_GETFLAGS:
  put_fs_long (inode->u.ext2_i.i_flags, (long *) arg);
  return 0;
case EXT2_IOC_SETFLAGS:
  if ((current->euid != inode->i_uid) && !suser())
   return -EPERM;
  if (IS_RDONLY(inode)) //可能是检测节点本身是否是可以改变的
   return -EROFS;
  inode->u.ext2_i.i_flags = get_fs_long ((long *) arg);
  inode->i_ctime = CURRENT_TIME;
  inode->i_dirt = 1;
  return 0;
case EXT2_IOC_GETVERSION:
  put_fs_long (inode->u.ext2_i.i_version, (long *) arg);
  return 0;
case EXT2_IOC_SETVERSION:
  if ((current->euid != inode->i_uid) && !suser())
   return -EPERM;
  if (IS_RDONLY(inode))
   return -EROFS;
  inode->u.ext2_i.i_version = get_fs_long ((long *) arg);
  inode->i_ctime = CURRENT_TIME;
  inode->i_dirt = 1;
  return 0;
default:
  return -EINVAL;
}
}

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