/*
   * page.h - buffer/page management specific to NILFS
   *
   * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
   *
   * Written by Ryusuke Konishi <ryusuke@osrg.net>,
   *            Seiji Kihara <kihara@osrg.net>.
   */
  
  #ifndef _NILFS_PAGE_H
  #define _NILFS_PAGE_H
  
  #include <linux/buffer_head.h>
  #include "nilfs.h"
  
  /*
   * Extended buffer state bits
   */
  enum {
  	BH_NILFS_Allocated = BH_PrivateStart,
  	BH_NILFS_Node,
  	BH_NILFS_Volatile,

  	BH_NILFS_Checked,

  	BH_NILFS_Redirected,

  };

  BUFFER_FNS(NILFS_Node, nilfs_node)		/* nilfs node buffers */
  BUFFER_FNS(NILFS_Volatile, nilfs_volatile)

  BUFFER_FNS(NILFS_Checked, nilfs_checked)	/* buffer is verified */

  BUFFER_FNS(NILFS_Redirected, nilfs_redirected)	/* redirected to a copy */

  int __nilfs_clear_page_dirty(struct page *);
  
  struct buffer_head *nilfs_grab_buffer(struct inode *, struct address_space *,
  				      unsigned long, unsigned long);
  void nilfs_forget_buffer(struct buffer_head *);
  void nilfs_copy_buffer(struct buffer_head *, struct buffer_head *);
  int nilfs_page_buffers_clean(struct page *);
  void nilfs_page_bug(struct page *);

  
  int nilfs_copy_dirty_pages(struct address_space *, struct address_space *);
  void nilfs_copy_back_pages(struct address_space *, struct address_space *);
  void nilfs_clear_dirty_pages(struct address_space *);

  void nilfs_mapping_init(struct address_space *mapping, struct inode *inode,

  			struct backing_dev_info *bdi);

  unsigned nilfs_page_count_clean_buffers(struct page *, unsigned, unsigned);

  unsigned long nilfs_find_uncommitted_extent(struct inode *inode,
  					    sector_t start_blk,
  					    sector_t *blkoff);

  
  #define NILFS_PAGE_BUG(page, m, a...) \
  	do { nilfs_page_bug(page); BUG(); } while (0)
  
  static inline struct buffer_head *
  nilfs_page_get_nth_block(struct page *page, unsigned int count)
  {
  	struct buffer_head *bh = page_buffers(page);
  
  	while (count-- > 0)
  		bh = bh->b_this_page;
  	get_bh(bh);
  	return bh;
  }
  
  #endif /* _NILFS_PAGE_H */