linux/fs/nilfs2/bmap.h
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   1/*
   2 * bmap.h - NILFS block mapping.
   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 * Written by Koji Sato <koji@osrg.net>.
  21 */
  22
  23#ifndef _NILFS_BMAP_H
  24#define _NILFS_BMAP_H
  25
  26#include <linux/types.h>
  27#include <linux/fs.h>
  28#include <linux/buffer_head.h>
  29#include <linux/nilfs2_fs.h>
  30#include "alloc.h"
  31#include "dat.h"
  32
  33#define NILFS_BMAP_INVALID_PTR  0
  34
  35#define nilfs_bmap_keydiff_abs(diff)    ((diff) < 0 ? -(diff) : (diff))
  36
  37
  38struct nilfs_bmap;
  39
  40/**
  41 * union nilfs_bmap_ptr_req - request for bmap ptr
  42 * @bpr_ptr: bmap pointer
  43 * @bpr_req: request for persistent allocator
  44 */
  45union nilfs_bmap_ptr_req {
  46        __u64 bpr_ptr;
  47        struct nilfs_palloc_req bpr_req;
  48};
  49
  50/**
  51 * struct nilfs_bmap_stats - bmap statistics
  52 * @bs_nblocks: number of blocks created or deleted
  53 */
  54struct nilfs_bmap_stats {
  55        unsigned int bs_nblocks;
  56};
  57
  58/**
  59 * struct nilfs_bmap_operations - bmap operation table
  60 */
  61struct nilfs_bmap_operations {
  62        int (*bop_lookup)(const struct nilfs_bmap *, __u64, int, __u64 *);
  63        int (*bop_lookup_contig)(const struct nilfs_bmap *, __u64, __u64 *,
  64                                 unsigned);
  65        int (*bop_insert)(struct nilfs_bmap *, __u64, __u64);
  66        int (*bop_delete)(struct nilfs_bmap *, __u64);
  67        void (*bop_clear)(struct nilfs_bmap *);
  68
  69        int (*bop_propagate)(struct nilfs_bmap *, struct buffer_head *);
  70        void (*bop_lookup_dirty_buffers)(struct nilfs_bmap *,
  71                                         struct list_head *);
  72
  73        int (*bop_assign)(struct nilfs_bmap *,
  74                          struct buffer_head **,
  75                          sector_t,
  76                          union nilfs_binfo *);
  77        int (*bop_mark)(struct nilfs_bmap *, __u64, int);
  78
  79        /* The following functions are internal use only. */
  80        int (*bop_last_key)(const struct nilfs_bmap *, __u64 *);
  81        int (*bop_check_insert)(const struct nilfs_bmap *, __u64);
  82        int (*bop_check_delete)(struct nilfs_bmap *, __u64);
  83        int (*bop_gather_data)(struct nilfs_bmap *, __u64 *, __u64 *, int);
  84};
  85
  86
  87#define NILFS_BMAP_SIZE         (NILFS_INODE_BMAP_SIZE * sizeof(__le64))
  88#define NILFS_BMAP_KEY_BIT      (sizeof(unsigned long) * 8 /* CHAR_BIT */)
  89#define NILFS_BMAP_NEW_PTR_INIT \
  90        (1UL << (sizeof(unsigned long) * 8 /* CHAR_BIT */ - 1))
  91
  92static inline int nilfs_bmap_is_new_ptr(unsigned long ptr)
  93{
  94        return !!(ptr & NILFS_BMAP_NEW_PTR_INIT);
  95}
  96
  97
  98/**
  99 * struct nilfs_bmap - bmap structure
 100 * @b_u: raw data
 101 * @b_sem: semaphore
 102 * @b_inode: owner of bmap
 103 * @b_ops: bmap operation table
 104 * @b_last_allocated_key: last allocated key for data block
 105 * @b_last_allocated_ptr: last allocated ptr for data block
 106 * @b_ptr_type: pointer type
 107 * @b_state: state
 108 * @b_nchildren_per_block: maximum number of child nodes for non-root nodes
 109 */
 110struct nilfs_bmap {
 111        union {
 112                __u8 u_flags;
 113                __le64 u_data[NILFS_BMAP_SIZE / sizeof(__le64)];
 114        } b_u;
 115        struct rw_semaphore b_sem;
 116        struct inode *b_inode;
 117        const struct nilfs_bmap_operations *b_ops;
 118        __u64 b_last_allocated_key;
 119        __u64 b_last_allocated_ptr;
 120        int b_ptr_type;
 121        int b_state;
 122        __u16 b_nchildren_per_block;
 123};
 124
 125/* pointer type */
 126#define NILFS_BMAP_PTR_P        0       /* physical block number (i.e. LBN) */
 127#define NILFS_BMAP_PTR_VS       1       /* virtual block number (single
 128                                           version) */
 129#define NILFS_BMAP_PTR_VM       2       /* virtual block number (has multiple
 130                                           versions) */
 131#define NILFS_BMAP_PTR_U        (-1)    /* never perform pointer operations */
 132
 133#define NILFS_BMAP_USE_VBN(bmap)        ((bmap)->b_ptr_type > 0)
 134
 135/* state */
 136#define NILFS_BMAP_DIRTY        0x00000001
 137
 138/**
 139 * struct nilfs_bmap_store - shadow copy of bmap state
 140 * @data: cached raw block mapping of on-disk inode
 141 * @last_allocated_key: cached value of last allocated key for data block
 142 * @last_allocated_ptr: cached value of last allocated ptr for data block
 143 * @state: cached value of state field of bmap structure
 144 */
 145struct nilfs_bmap_store {
 146        __le64 data[NILFS_BMAP_SIZE / sizeof(__le64)];
 147        __u64 last_allocated_key;
 148        __u64 last_allocated_ptr;
 149        int state;
 150};
 151
 152int nilfs_bmap_test_and_clear_dirty(struct nilfs_bmap *);
 153int nilfs_bmap_read(struct nilfs_bmap *, struct nilfs_inode *);
 154void nilfs_bmap_write(struct nilfs_bmap *, struct nilfs_inode *);
 155int nilfs_bmap_lookup_contig(struct nilfs_bmap *, __u64, __u64 *, unsigned);
 156int nilfs_bmap_insert(struct nilfs_bmap *, unsigned long, unsigned long);
 157int nilfs_bmap_delete(struct nilfs_bmap *, unsigned long);
 158int nilfs_bmap_last_key(struct nilfs_bmap *, unsigned long *);
 159int nilfs_bmap_truncate(struct nilfs_bmap *, unsigned long);
 160void nilfs_bmap_clear(struct nilfs_bmap *);
 161int nilfs_bmap_propagate(struct nilfs_bmap *, struct buffer_head *);
 162void nilfs_bmap_lookup_dirty_buffers(struct nilfs_bmap *, struct list_head *);
 163int nilfs_bmap_assign(struct nilfs_bmap *, struct buffer_head **,
 164                      unsigned long, union nilfs_binfo *);
 165int nilfs_bmap_lookup_at_level(struct nilfs_bmap *, __u64, int, __u64 *);
 166int nilfs_bmap_mark(struct nilfs_bmap *, __u64, int);
 167
 168void nilfs_bmap_init_gc(struct nilfs_bmap *);
 169
 170void nilfs_bmap_save(const struct nilfs_bmap *, struct nilfs_bmap_store *);
 171void nilfs_bmap_restore(struct nilfs_bmap *, const struct nilfs_bmap_store *);
 172
 173static inline int nilfs_bmap_lookup(struct nilfs_bmap *bmap, __u64 key,
 174                                    __u64 *ptr)
 175{
 176        return nilfs_bmap_lookup_at_level(bmap, key, 1, ptr);
 177}
 178
 179/*
 180 * Internal use only
 181 */
 182struct inode *nilfs_bmap_get_dat(const struct nilfs_bmap *);
 183
 184static inline int nilfs_bmap_prepare_alloc_ptr(struct nilfs_bmap *bmap,
 185                                               union nilfs_bmap_ptr_req *req,
 186                                               struct inode *dat)
 187{
 188        if (dat)
 189                return nilfs_dat_prepare_alloc(dat, &req->bpr_req);
 190        /* ignore target ptr */
 191        req->bpr_ptr = bmap->b_last_allocated_ptr++;
 192        return 0;
 193}
 194
 195static inline void nilfs_bmap_commit_alloc_ptr(struct nilfs_bmap *bmap,
 196                                               union nilfs_bmap_ptr_req *req,
 197                                               struct inode *dat)
 198{
 199        if (dat)
 200                nilfs_dat_commit_alloc(dat, &req->bpr_req);
 201}
 202
 203static inline void nilfs_bmap_abort_alloc_ptr(struct nilfs_bmap *bmap,
 204                                              union nilfs_bmap_ptr_req *req,
 205                                              struct inode *dat)
 206{
 207        if (dat)
 208                nilfs_dat_abort_alloc(dat, &req->bpr_req);
 209        else
 210                bmap->b_last_allocated_ptr--;
 211}
 212
 213static inline int nilfs_bmap_prepare_end_ptr(struct nilfs_bmap *bmap,
 214                                             union nilfs_bmap_ptr_req *req,
 215                                             struct inode *dat)
 216{
 217        return dat ? nilfs_dat_prepare_end(dat, &req->bpr_req) : 0;
 218}
 219
 220static inline void nilfs_bmap_commit_end_ptr(struct nilfs_bmap *bmap,
 221                                             union nilfs_bmap_ptr_req *req,
 222                                             struct inode *dat)
 223{
 224        if (dat)
 225                nilfs_dat_commit_end(dat, &req->bpr_req,
 226                                     bmap->b_ptr_type == NILFS_BMAP_PTR_VS);
 227}
 228
 229static inline void nilfs_bmap_abort_end_ptr(struct nilfs_bmap *bmap,
 230                                            union nilfs_bmap_ptr_req *req,
 231                                            struct inode *dat)
 232{
 233        if (dat)
 234                nilfs_dat_abort_end(dat, &req->bpr_req);
 235}
 236
 237static inline void nilfs_bmap_set_target_v(struct nilfs_bmap *bmap, __u64 key,
 238                                           __u64 ptr)
 239{
 240        bmap->b_last_allocated_key = key;
 241        bmap->b_last_allocated_ptr = ptr;
 242}
 243
 244__u64 nilfs_bmap_data_get_key(const struct nilfs_bmap *,
 245                              const struct buffer_head *);
 246
 247__u64 nilfs_bmap_find_target_seq(const struct nilfs_bmap *, __u64);
 248__u64 nilfs_bmap_find_target_in_group(const struct nilfs_bmap *);
 249
 250
 251/* Assume that bmap semaphore is locked. */
 252static inline int nilfs_bmap_dirty(const struct nilfs_bmap *bmap)
 253{
 254        return !!(bmap->b_state & NILFS_BMAP_DIRTY);
 255}
 256
 257/* Assume that bmap semaphore is locked. */
 258static inline void nilfs_bmap_set_dirty(struct nilfs_bmap *bmap)
 259{
 260        bmap->b_state |= NILFS_BMAP_DIRTY;
 261}
 262
 263/* Assume that bmap semaphore is locked. */
 264static inline void nilfs_bmap_clear_dirty(struct nilfs_bmap *bmap)
 265{
 266        bmap->b_state &= ~NILFS_BMAP_DIRTY;
 267}
 268
 269
 270#define NILFS_BMAP_LARGE        0x1
 271
 272#define NILFS_BMAP_SMALL_LOW    NILFS_DIRECT_KEY_MIN
 273#define NILFS_BMAP_SMALL_HIGH   NILFS_DIRECT_KEY_MAX
 274#define NILFS_BMAP_LARGE_LOW    NILFS_BTREE_ROOT_NCHILDREN_MAX
 275#define NILFS_BMAP_LARGE_HIGH   NILFS_BTREE_KEY_MAX
 276
 277#endif  /* _NILFS_BMAP_H */
 278
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