linux/fs/nilfs2/alloc.h
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   1/*
   2 * alloc.h - persistent object (dat entry/disk inode) allocator/deallocator
   3 *
   4 * Copyright (C) 2006-2008 Nippon Telegraph and Telephone Corporation.
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation; either version 2 of the License, or
   9 * (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 * GNU General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU General Public License
  17 * along with this program; if not, write to the Free Software
  18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19 *
  20 * Original code was written by Koji Sato <koji@osrg.net>.
  21 * Two allocators were unified by Ryusuke Konishi <ryusuke@osrg.net>,
  22 *                                Amagai Yoshiji <amagai@osrg.net>.
  23 */
  24
  25#ifndef _NILFS_ALLOC_H
  26#define _NILFS_ALLOC_H
  27
  28#include <linux/types.h>
  29#include <linux/buffer_head.h>
  30#include <linux/fs.h>
  31
  32/**
  33 * nilfs_palloc_entries_per_group - get the number of entries per group
  34 * @inode: inode of metadata file using this allocator
  35 *
  36 * The number of entries per group is defined by the number of bits
  37 * that a bitmap block can maintain.
  38 */
  39static inline unsigned long
  40nilfs_palloc_entries_per_group(const struct inode *inode)
  41{
  42        return 1UL << (inode->i_blkbits + 3 /* log2(8 = CHAR_BITS) */);
  43}
  44
  45int nilfs_palloc_init_blockgroup(struct inode *, unsigned);
  46int nilfs_palloc_get_entry_block(struct inode *, __u64, int,
  47                                 struct buffer_head **);
  48void *nilfs_palloc_block_get_entry(const struct inode *, __u64,
  49                                   const struct buffer_head *, void *);
  50
  51/**
  52 * nilfs_palloc_req - persistent allocator request and reply
  53 * @pr_entry_nr: entry number (vblocknr or inode number)
  54 * @pr_desc_bh: buffer head of the buffer containing block group descriptors
  55 * @pr_bitmap_bh: buffer head of the buffer containing a block group bitmap
  56 * @pr_entry_bh: buffer head of the buffer containing translation entries
  57 */
  58struct nilfs_palloc_req {
  59        __u64 pr_entry_nr;
  60        struct buffer_head *pr_desc_bh;
  61        struct buffer_head *pr_bitmap_bh;
  62        struct buffer_head *pr_entry_bh;
  63};
  64
  65int nilfs_palloc_prepare_alloc_entry(struct inode *,
  66                                     struct nilfs_palloc_req *);
  67void nilfs_palloc_commit_alloc_entry(struct inode *,
  68                                     struct nilfs_palloc_req *);
  69void nilfs_palloc_abort_alloc_entry(struct inode *, struct nilfs_palloc_req *);
  70void nilfs_palloc_commit_free_entry(struct inode *, struct nilfs_palloc_req *);
  71int nilfs_palloc_prepare_free_entry(struct inode *, struct nilfs_palloc_req *);
  72void nilfs_palloc_abort_free_entry(struct inode *, struct nilfs_palloc_req *);
  73int nilfs_palloc_freev(struct inode *, __u64 *, size_t);
  74
  75#define nilfs_set_bit_atomic            ext2_set_bit_atomic
  76#define nilfs_clear_bit_atomic          ext2_clear_bit_atomic
  77#define nilfs_find_next_zero_bit        find_next_zero_bit_le
  78
  79/**
  80 * struct nilfs_bh_assoc - block offset and buffer head association
  81 * @blkoff: block offset
  82 * @bh: buffer head
  83 */
  84struct nilfs_bh_assoc {
  85        unsigned long blkoff;
  86        struct buffer_head *bh;
  87};
  88
  89/**
  90 * struct nilfs_palloc_cache - persistent object allocator cache
  91 * @lock: cache protecting lock
  92 * @prev_desc: blockgroup descriptors cache
  93 * @prev_bitmap: blockgroup bitmap cache
  94 * @prev_entry: translation entries cache
  95 */
  96struct nilfs_palloc_cache {
  97        spinlock_t lock;
  98        struct nilfs_bh_assoc prev_desc;
  99        struct nilfs_bh_assoc prev_bitmap;
 100        struct nilfs_bh_assoc prev_entry;
 101};
 102
 103void nilfs_palloc_setup_cache(struct inode *inode,
 104                              struct nilfs_palloc_cache *cache);
 105void nilfs_palloc_clear_cache(struct inode *inode);
 106void nilfs_palloc_destroy_cache(struct inode *inode);
 107
 108#endif  /* _NILFS_ALLOC_H */
 109
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