/*
   *  linux/fs/bad_inode.c
   *
   *  Copyright (C) 1997, Stephen Tweedie
   *
   *  Provide stub functions for unreadable inodes
   *
   *  Fabian Frederick : August 2003 - All file operations assigned to EIO
   */
  
  #include <linux/fs.h>
  #include <linux/export.h>
  #include <linux/stat.h>
  #include <linux/time.h>
  #include <linux/namei.h>
  #include <linux/poll.h>
  
  
  static loff_t bad_file_llseek(struct file *file, loff_t offset, int whence)
  {
  	return -EIO;
  }
  
  static ssize_t bad_file_read(struct file *filp, char __user *buf,
  			size_t size, loff_t *ppos)
  {
          return -EIO;
  }
  
  static ssize_t bad_file_write(struct file *filp, const char __user *buf,
  			size_t siz, loff_t *ppos)
  {
          return -EIO;
  }
  
  static ssize_t bad_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
  			unsigned long nr_segs, loff_t pos)
  {
  	return -EIO;
  }
  
  static ssize_t bad_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
  			unsigned long nr_segs, loff_t pos)
  {
  	return -EIO;
  }
  
  static int bad_file_readdir(struct file *file, struct dir_context *ctx)
  {
  	return -EIO;
  }
  
  static unsigned int bad_file_poll(struct file *filp, poll_table *wait)
  {
  	return POLLERR;
  }
  
  static long bad_file_unlocked_ioctl(struct file *file, unsigned cmd,
  			unsigned long arg)
  {
  	return -EIO;
  }
  
  static long bad_file_compat_ioctl(struct file *file, unsigned int cmd,
  			unsigned long arg)
  {
  	return -EIO;
  }
  
  static int bad_file_mmap(struct file *file, struct vm_area_struct *vma)
  {
  	return -EIO;
  }
  
  static int bad_file_open(struct inode *inode, struct file *filp)
  {
  	return -EIO;
  }
  
  static int bad_file_flush(struct file *file, fl_owner_t id)
  {
  	return -EIO;
  }
  
  static int bad_file_release(struct inode *inode, struct file *filp)
  {
  	return -EIO;
  }
  
  static int bad_file_fsync(struct file *file, loff_t start, loff_t end,
  			  int datasync)
  {
  	return -EIO;
  }
  
  static int bad_file_aio_fsync(struct kiocb *iocb, int datasync)
  {
  	return -EIO;
  }
  
  static int bad_file_fasync(int fd, struct file *filp, int on)
  {
  	return -EIO;
  }
  
  static int bad_file_lock(struct file *file, int cmd, struct file_lock *fl)
  {
  	return -EIO;
  }
  
  static ssize_t bad_file_sendpage(struct file *file, struct page *page,
  			int off, size_t len, loff_t *pos, int more)
  {
  	return -EIO;
  }
  
  static unsigned long bad_file_get_unmapped_area(struct file *file,
  				unsigned long addr, unsigned long len,
  				unsigned long pgoff, unsigned long flags)
  {
  	return -EIO;
  }
  
  static int bad_file_check_flags(int flags)
  {
  	return -EIO;
  }
  
  static int bad_file_flock(struct file *filp, int cmd, struct file_lock *fl)
  {
  	return -EIO;
  }
  
  static ssize_t bad_file_splice_write(struct pipe_inode_info *pipe,
  			struct file *out, loff_t *ppos, size_t len,
  			unsigned int flags)
  {
  	return -EIO;
  }
  
  static ssize_t bad_file_splice_read(struct file *in, loff_t *ppos,
  			struct pipe_inode_info *pipe, size_t len,
  			unsigned int flags)
  {
  	return -EIO;
  }
  
  static const struct file_operations bad_file_ops =
  {
  	.llseek		= bad_file_llseek,
  	.read		= bad_file_read,
  	.write		= bad_file_write,
  	.aio_read	= bad_file_aio_read,
  	.aio_write	= bad_file_aio_write,
  	.iterate	= bad_file_readdir,
  	.poll		= bad_file_poll,
  	.unlocked_ioctl	= bad_file_unlocked_ioctl,
  	.compat_ioctl	= bad_file_compat_ioctl,
  	.mmap		= bad_file_mmap,
  	.open		= bad_file_open,
  	.flush		= bad_file_flush,
  	.release	= bad_file_release,
  	.fsync		= bad_file_fsync,
  	.aio_fsync	= bad_file_aio_fsync,
  	.fasync		= bad_file_fasync,
  	.lock		= bad_file_lock,
  	.sendpage	= bad_file_sendpage,
  	.get_unmapped_area = bad_file_get_unmapped_area,
  	.check_flags	= bad_file_check_flags,
  	.flock		= bad_file_flock,
  	.splice_write	= bad_file_splice_write,
  	.splice_read	= bad_file_splice_read,
  };
  
  static int bad_inode_create (struct inode *dir, struct dentry *dentry,
  		umode_t mode, bool excl)
  {
  	return -EIO;
  }
  
  static struct dentry *bad_inode_lookup(struct inode *dir,
  			struct dentry *dentry, unsigned int flags)
  {
  	return ERR_PTR(-EIO);
  }
  
  static int bad_inode_link (struct dentry *old_dentry, struct inode *dir,
  		struct dentry *dentry)
  {
  	return -EIO;
  }
  
  static int bad_inode_unlink(struct inode *dir, struct dentry *dentry)
  {
  	return -EIO;
  }
  
  static int bad_inode_symlink (struct inode *dir, struct dentry *dentry,
  		const char *symname)
  {
  	return -EIO;
  }
  
  static int bad_inode_mkdir(struct inode *dir, struct dentry *dentry,
  			umode_t mode)
  {
  	return -EIO;
  }
  
  static int bad_inode_rmdir (struct inode *dir, struct dentry *dentry)
  {
  	return -EIO;
  }
  
  static int bad_inode_mknod (struct inode *dir, struct dentry *dentry,
  			umode_t mode, dev_t rdev)
  {
  	return -EIO;
  }
  
  static int bad_inode_rename (struct inode *old_dir, struct dentry *old_dentry,
  		struct inode *new_dir, struct dentry *new_dentry)
  {
  	return -EIO;
  }
  
  static int bad_inode_readlink(struct dentry *dentry, char __user *buffer,
  		int buflen)
  {
  	return -EIO;
  }
  
  static int bad_inode_permission(struct inode *inode, int mask)
  {
  	return -EIO;
  }
  
  static int bad_inode_getattr(struct vfsmount *mnt, struct dentry *dentry,
  			struct kstat *stat)
  {
  	return -EIO;
  }
  
  static int bad_inode_setattr(struct dentry *direntry, struct iattr *attrs)
  {
  	return -EIO;
  }
  
  static int bad_inode_setxattr(struct dentry *dentry, const char *name,
  		const void *value, size_t size, int flags)
  {
  	return -EIO;
  }
  
  static ssize_t bad_inode_getxattr(struct dentry *dentry, const char *name,
  			void *buffer, size_t size)
  {
  	return -EIO;
  }
  
  static ssize_t bad_inode_listxattr(struct dentry *dentry, char *buffer,
  			size_t buffer_size)
  {
  	return -EIO;
  }
  
  static int bad_inode_removexattr(struct dentry *dentry, const char *name)
  {
  	return -EIO;
  }
  
  static const struct inode_operations bad_inode_ops =
  {
  	.create		= bad_inode_create,
  	.lookup		= bad_inode_lookup,
  	.link		= bad_inode_link,
  	.unlink		= bad_inode_unlink,
  	.symlink	= bad_inode_symlink,
  	.mkdir		= bad_inode_mkdir,
  	.rmdir		= bad_inode_rmdir,
  	.mknod		= bad_inode_mknod,
  	.rename		= bad_inode_rename,
  	.readlink	= bad_inode_readlink,
  	/* follow_link must be no-op, otherwise unmounting this inode
  	   won't work */
  	/* put_link returns void */
  	/* truncate returns void */
  	.permission	= bad_inode_permission,
  	.getattr	= bad_inode_getattr,
  	.setattr	= bad_inode_setattr,
  	.setxattr	= bad_inode_setxattr,
  	.getxattr	= bad_inode_getxattr,
  	.listxattr	= bad_inode_listxattr,
  	.removexattr	= bad_inode_removexattr,
  };
  
  
  /*
   * When a filesystem is unable to read an inode due to an I/O error in
   * its read_inode() function, it can call make_bad_inode() to return a
   * set of stubs which will return EIO errors as required. 
   *
   * We only need to do limited initialisation: all other fields are
   * preinitialised to zero automatically.
   */
   
  /**
   *	make_bad_inode - mark an inode bad due to an I/O error
   *	@inode: Inode to mark bad
   *
   *	When an inode cannot be read due to a media or remote network
   *	failure this function makes the inode "bad" and causes I/O operations
   *	on it to fail from this point on.
   */
   
  void make_bad_inode(struct inode *inode)
  {
  	remove_inode_hash(inode);
  
  	inode->i_mode = S_IFREG;
  	inode->i_atime = inode->i_mtime = inode->i_ctime =
  		current_fs_time(inode->i_sb);
  	inode->i_op = &bad_inode_ops;	
  	inode->i_fop = &bad_file_ops;	
  }
  EXPORT_SYMBOL(make_bad_inode);
  
  /*
   * This tests whether an inode has been flagged as bad. The test uses
   * &bad_inode_ops to cover the case of invalidated inodes as well as
   * those created by make_bad_inode() above.
   */
   
  /**
   *	is_bad_inode - is an inode errored
   *	@inode: inode to test
   *
   *	Returns true if the inode in question has been marked as bad.
   */
   
  int is_bad_inode(struct inode *inode)
  {
  	return (inode->i_op == &bad_inode_ops);	
  }
  
  EXPORT_SYMBOL(is_bad_inode);
  
  /**
   * iget_failed - Mark an under-construction inode as dead and release it
   * @inode: The inode to discard
   *
   * Mark an under-construction inode as dead and release it.
   */
  void iget_failed(struct inode *inode)
  {
  	make_bad_inode(inode);
  	unlock_new_inode(inode);
  	iput(inode);
  }
  EXPORT_SYMBOL(iget_failed);