/*
   * alloc.h - persistent object (dat entry/disk inode) allocator/deallocator
   *
   * Copyright (C) 2006-2008 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
   *
   * Original code was written by Koji Sato <koji@osrg.net>.
   * Two allocators were unified by Ryusuke Konishi <ryusuke@osrg.net>,
   *                                Amagai Yoshiji <amagai@osrg.net>.
   */
  
  #ifndef _NILFS_ALLOC_H
  #define _NILFS_ALLOC_H
  
  #include <linux/types.h>
  #include <linux/buffer_head.h>
  #include <linux/fs.h>

  /**
   * nilfs_palloc_entries_per_group - get the number of entries per group
   * @inode: inode of metadata file using this allocator
   *
   * The number of entries per group is defined by the number of bits
   * that a bitmap block can maintain.
   */

  static inline unsigned long
  nilfs_palloc_entries_per_group(const struct inode *inode)
  {
  	return 1UL << (inode->i_blkbits + 3 /* log2(8 = CHAR_BITS) */);
  }
  
  int nilfs_palloc_init_blockgroup(struct inode *, unsigned);
  int nilfs_palloc_get_entry_block(struct inode *, __u64, int,
  				 struct buffer_head **);
  void *nilfs_palloc_block_get_entry(const struct inode *, __u64,
  				   const struct buffer_head *, void *);
  
  /**

   * nilfs_palloc_req - persistent allocator request and reply

   * @pr_entry_nr: entry number (vblocknr or inode number)
   * @pr_desc_bh: buffer head of the buffer containing block group descriptors
   * @pr_bitmap_bh: buffer head of the buffer containing a block group bitmap
   * @pr_entry_bh: buffer head of the buffer containing translation entries
   */
  struct nilfs_palloc_req {
  	__u64 pr_entry_nr;
  	struct buffer_head *pr_desc_bh;
  	struct buffer_head *pr_bitmap_bh;
  	struct buffer_head *pr_entry_bh;
  };
  
  int nilfs_palloc_prepare_alloc_entry(struct inode *,
  				     struct nilfs_palloc_req *);
  void nilfs_palloc_commit_alloc_entry(struct inode *,
  				     struct nilfs_palloc_req *);
  void nilfs_palloc_abort_alloc_entry(struct inode *, struct nilfs_palloc_req *);
  void nilfs_palloc_commit_free_entry(struct inode *, struct nilfs_palloc_req *);
  int nilfs_palloc_prepare_free_entry(struct inode *, struct nilfs_palloc_req *);
  void nilfs_palloc_abort_free_entry(struct inode *, struct nilfs_palloc_req *);
  int nilfs_palloc_freev(struct inode *, __u64 *, size_t);
  
  #define nilfs_set_bit_atomic		ext2_set_bit_atomic
  #define nilfs_clear_bit_atomic		ext2_clear_bit_atomic
  #define nilfs_find_next_zero_bit	ext2_find_next_zero_bit

  /*
   * persistent object allocator cache
   */
  
  struct nilfs_bh_assoc {
  	unsigned long blkoff;
  	struct buffer_head *bh;
  };
  
  struct nilfs_palloc_cache {
  	spinlock_t lock;
  	struct nilfs_bh_assoc prev_desc;
  	struct nilfs_bh_assoc prev_bitmap;
  	struct nilfs_bh_assoc prev_entry;
  };
  
  void nilfs_palloc_setup_cache(struct inode *inode,
  			      struct nilfs_palloc_cache *cache);
  void nilfs_palloc_clear_cache(struct inode *inode);
  void nilfs_palloc_destroy_cache(struct inode *inode);

  #endif	/* _NILFS_ALLOC_H */