fs/nilfs2/bmap.h

   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
  38 struct 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  */
  45 union 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  */
  54 struct nilfs_bmap_stats {
  55         unsigned int bs_nblocks;
  56 };
  57
  58 /**
  59  * struct nilfs_bmap_operations - bmap operation table
  60  */
  61 struct 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
  92 static 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  */
 110 struct 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  */
 145 struct 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
 152 int nilfs_bmap_test_and_clear_dirty(struct nilfs_bmap *);
 153 int nilfs_bmap_read(struct nilfs_bmap *, struct nilfs_inode *);
 154 void nilfs_bmap_write(struct nilfs_bmap *, struct nilfs_inode *);
 155 int nilfs_bmap_lookup_contig(struct nilfs_bmap *, __u64, __u64 *, unsigned);
 156 int nilfs_bmap_insert(struct nilfs_bmap *, unsigned long, unsigned long);
 157 int nilfs_bmap_delete(struct nilfs_bmap *, unsigned long);
 158 int nilfs_bmap_last_key(struct nilfs_bmap *, unsigned long *);
 159 int nilfs_bmap_truncate(struct nilfs_bmap *, unsigned long);
 160 void nilfs_bmap_clear(struct nilfs_bmap *);
 161 int nilfs_bmap_propagate(struct nilfs_bmap *, struct buffer_head *);
 162 void nilfs_bmap_lookup_dirty_buffers(struct nilfs_bmap *, struct list_head *);
 163 int nilfs_bmap_assign(struct nilfs_bmap *, struct buffer_head **,
 164                       unsigned long, union nilfs_binfo *);
 165 int nilfs_bmap_lookup_at_level(struct nilfs_bmap *, __u64, int, __u64 *);
 166 int nilfs_bmap_mark(struct nilfs_bmap *, __u64, int);
 167
 168 void nilfs_bmap_init_gc(struct nilfs_bmap *);
 169
 170 void nilfs_bmap_save(const struct nilfs_bmap *, struct nilfs_bmap_store *);
 171 void nilfs_bmap_restore(struct nilfs_bmap *, const struct nilfs_bmap_store *);
 172
 173 static 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  */
 182 struct inode *nilfs_bmap_get_dat(const struct nilfs_bmap *);
 183
 184 static 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
 195 static 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
 203 static 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
 213 static 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
 220 static 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
 229 static 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
 237 static 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. */
 252 static 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. */
 258 static 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. */
 264 static 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 */