lib/ext2fs/alloc.c

   1 /*
   2  * alloc.c --- allocate new inodes, blocks for ext2fs
   3  *
   4  * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o.
   5  *
   6  * %Begin-Header%
   7  * This file may be redistributed under the terms of the GNU Public
   8  * License.
   9  * %End-Header%
  10  *
  11  */
  12
  13 #include <stdio.h>
  14 #if HAVE_UNISTD_H
  15 #include <unistd.h>
  16 #endif
  17 #include <time.h>
  18 #include <string.h>
  19 #if HAVE_SYS_STAT_H
  20 #include <sys/stat.h>
  21 #endif
  22 #if HAVE_SYS_TYPES_H
  23 #include <sys/types.h>
  24 #endif
  25
  26 #include "ext2_fs.h"
  27 #include "ext2fs.h"
  28
  29 /*
  30  * Check for uninit block bitmaps and deal with them appropriately
  31  */
  32 static void check_block_uninit(ext2_filsys fs, ext2fs_block_bitmap map,
  33                                dgrp_t group)
  34 {
  35         blk_t           i;
  36         blk64_t         blk, super_blk, old_desc_blk, new_desc_blk;
  37         int             old_desc_blocks;
  38
  39         if (!(EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
  40                                          EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) ||
  41             !(fs->group_desc[group].bg_flags & EXT2_BG_BLOCK_UNINIT))
  42                 return;
  43
  44         blk = (group * fs->super->s_blocks_per_group) +
  45                 fs->super->s_first_data_block;
  46
  47         ext2fs_super_and_bgd_loc2(fs, group, &super_blk,
  48                                   &old_desc_blk, &new_desc_blk, 0);
  49
  50         if (fs->super->s_feature_incompat &
  51             EXT2_FEATURE_INCOMPAT_META_BG)
  52                 old_desc_blocks = fs->super->s_first_meta_bg;
  53         else
  54                 old_desc_blocks = fs->desc_blocks + fs->super->s_reserved_gdt_blocks;
  55
  56         for (i=0; i < fs->super->s_blocks_per_group; i++, blk++) {
  57                 if ((blk == super_blk) ||
  58                     (old_desc_blk && old_desc_blocks &&
  59                      (blk >= old_desc_blk) &&
  60                      (blk < old_desc_blk + old_desc_blocks)) ||
  61                     (new_desc_blk && (blk == new_desc_blk)) ||
  62                     (blk == fs->group_desc[group].bg_block_bitmap) ||
  63                     (blk == fs->group_desc[group].bg_inode_bitmap) ||
  64                     (blk >= fs->group_desc[group].bg_inode_table &&
  65                      (blk < fs->group_desc[group].bg_inode_table
  66                       + fs->inode_blocks_per_group)))
  67                         ext2fs_fast_mark_block_bitmap2(map, blk);
  68                 else
  69                         ext2fs_fast_unmark_block_bitmap2(map, blk);
  70         }
  71         fs->group_desc[group].bg_flags &= ~EXT2_BG_BLOCK_UNINIT;
  72         ext2fs_group_desc_csum_set(fs, group);
  73 }
  74
  75 /*
  76  * Check for uninit inode bitmaps and deal with them appropriately
  77  */
  78 static void check_inode_uninit(ext2_filsys fs, ext2fs_inode_bitmap map,
  79                           dgrp_t group)
  80 {
  81         ext2_ino_t      i, ino;
  82
  83         if (!(EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
  84                                          EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) ||
  85             !(fs->group_desc[group].bg_flags & EXT2_BG_INODE_UNINIT))
  86                 return;
  87
  88         ino = (group * fs->super->s_inodes_per_group) + 1;
  89         for (i=0; i < fs->super->s_inodes_per_group; i++, ino++)
  90                 ext2fs_fast_unmark_inode_bitmap2(map, ino);
  91
  92         fs->group_desc[group].bg_flags &= ~EXT2_BG_INODE_UNINIT;
  93         check_block_uninit(fs, fs->block_map, group);
  94 }
  95
  96 /*
  97  * Right now, just search forward from the parent directory's block
  98  * group to find the next free inode.
  99  *
 100  * Should have a special policy for directories.
 101  */
 102 errcode_t ext2fs_new_inode(ext2_filsys fs, ext2_ino_t dir,
 103                            int mode EXT2FS_ATTR((unused)),
 104                            ext2fs_inode_bitmap map, ext2_ino_t *ret)
 105 {
 106         ext2_ino_t      dir_group = 0;
 107         ext2_ino_t      i;
 108         ext2_ino_t      start_inode;
 109
 110         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 111
 112         if (!map)
 113                 map = fs->inode_map;
 114         if (!map)
 115                 return EXT2_ET_NO_INODE_BITMAP;
 116
 117         if (dir > 0)
 118                 dir_group = (dir - 1) / EXT2_INODES_PER_GROUP(fs->super);
 119
 120         start_inode = (dir_group * EXT2_INODES_PER_GROUP(fs->super)) + 1;
 121         if (start_inode < EXT2_FIRST_INODE(fs->super))
 122                 start_inode = EXT2_FIRST_INODE(fs->super);
 123         if (start_inode > fs->super->s_inodes_count)
 124                 return EXT2_ET_INODE_ALLOC_FAIL;
 125         i = start_inode;
 126
 127         do {
 128                 if (((i - 1) % EXT2_INODES_PER_GROUP(fs->super)) == 0)
 129                         check_inode_uninit(fs, map, (i - 1) /
 130                                            EXT2_INODES_PER_GROUP(fs->super));
 131
 132                 if (!ext2fs_fast_test_inode_bitmap2(map, i))
 133                         break;
 134                 i++;
 135                 if (i > fs->super->s_inodes_count)
 136                         i = EXT2_FIRST_INODE(fs->super);
 137         } while (i != start_inode);
 138
 139         if (ext2fs_test_inode_bitmap2(map, i))
 140                 return EXT2_ET_INODE_ALLOC_FAIL;
 141         *ret = i;
 142         return 0;
 143 }
 144
 145 /*
 146  * Stupid algorithm --- we now just search forward starting from the
 147  * goal.  Should put in a smarter one someday....
 148  */
 149 errcode_t ext2fs_new_block2(ext2_filsys fs, blk64_t goal,
 150                            ext2fs_block_bitmap map, blk64_t *ret)
 151 {
 152         blk64_t i;
 153
 154         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 155
 156         if (!map)
 157                 map = fs->block_map;
 158         if (!map)
 159                 return EXT2_ET_NO_BLOCK_BITMAP;
 160         if (!goal || (goal >= fs->super->s_blocks_count))
 161                 goal = fs->super->s_first_data_block;
 162         i = goal;
 163         check_block_uninit(fs, map,
 164                            (i - fs->super->s_first_data_block) /
 165                            EXT2_BLOCKS_PER_GROUP(fs->super));
 166         do {
 167                 if (((i - fs->super->s_first_data_block) %
 168                      EXT2_BLOCKS_PER_GROUP(fs->super)) == 0)
 169                         check_block_uninit(fs, map,
 170                                            (i - fs->super->s_first_data_block) /
 171                                            EXT2_BLOCKS_PER_GROUP(fs->super));
 172
 173                 if (!ext2fs_fast_test_block_bitmap2(map, i)) {
 174                         *ret = i;
 175                         return 0;
 176                 }
 177                 i++;
 178                 if (i >= fs->super->s_blocks_count)
 179                         i = fs->super->s_first_data_block;
 180         } while (i != goal);
 181         return EXT2_ET_BLOCK_ALLOC_FAIL;
 182 }
 183
 184 errcode_t ext2fs_new_block(ext2_filsys fs, blk_t goal,
 185                            ext2fs_block_bitmap map, blk_t *ret)
 186 {
 187         errcode_t retval;
 188         blk64_t val;
 189         retval = ext2fs_new_block2(fs, goal, map, &val);
 190         if (!retval)
 191                 *ret = (blk_t) val;
 192         return retval;
 193 }
 194
 195 /*
 196  * This function zeros out the allocated block, and updates all of the
 197  * appropriate filesystem records.
 198  */
 199 errcode_t ext2fs_alloc_block2(ext2_filsys fs, blk64_t goal,
 200                              char *block_buf, blk64_t *ret)
 201 {
 202         errcode_t       retval;
 203         blk64_t         block;
 204         char            *buf = 0;
 205
 206         if (!block_buf) {
 207                 retval = ext2fs_get_mem(fs->blocksize, &buf);
 208                 if (retval)
 209                         return retval;
 210                 block_buf = buf;
 211         }
 212         memset(block_buf, 0, fs->blocksize);
 213
 214         if (fs->get_alloc_block) {
 215                 retval = (fs->get_alloc_block)(fs, goal, &block);
 216                 if (retval)
 217                         goto fail;
 218         } else {
 219                 if (!fs->block_map) {
 220                         retval = ext2fs_read_block_bitmap(fs);
 221                         if (retval)
 222                                 goto fail;
 223                 }
 224
 225                 retval = ext2fs_new_block2(fs, goal, 0, &block);
 226                 if (retval)
 227                         goto fail;
 228         }
 229
 230         retval = io_channel_write_blk64(fs->io, block, 1, block_buf);
 231         if (retval)
 232                 goto fail;
 233
 234         ext2fs_block_alloc_stats2(fs, block, +1);
 235         *ret = block;
 236
 237 fail:
 238         if (buf)
 239                 ext2fs_free_mem(&buf);
 240         return retval;
 241 }
 242
 243 errcode_t ext2fs_alloc_block(ext2_filsys fs, blk_t goal,
 244                              char *block_buf, blk_t *ret)
 245 {
 246         errcode_t retval;
 247         blk64_t val;
 248         retval = ext2fs_alloc_block2(fs, goal, block_buf, &val);
 249         if (!retval)
 250                 *ret = (blk_t) val;
 251         return retval;
 252 }
 253
 254 errcode_t ext2fs_get_free_blocks2(ext2_filsys fs, blk64_t start, blk64_t finish,
 255                                  int num, ext2fs_block_bitmap map, blk64_t *ret)
 256 {
 257         blk64_t b = start;
 258
 259         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 260
 261         if (!map)
 262                 map = fs->block_map;
 263         if (!map)
 264                 return EXT2_ET_NO_BLOCK_BITMAP;
 265         if (!b)
 266                 b = fs->super->s_first_data_block;
 267         if (!finish)
 268                 finish = start;
 269         if (!num)
 270                 num = 1;
 271         do {
 272                 if (b+num-1 > fs->super->s_blocks_count)
 273                         b = fs->super->s_first_data_block;
 274                 if (ext2fs_fast_test_block_bitmap_range2(map, b, num)) {
 275                         *ret = b;
 276                         return 0;
 277                 }
 278                 b++;
 279         } while (b != finish);
 280         return EXT2_ET_BLOCK_ALLOC_FAIL;
 281 }
 282
 283 errcode_t ext2fs_get_free_blocks(ext2_filsys fs, blk_t start, blk_t finish,
 284                                  int num, ext2fs_block_bitmap map, blk_t *ret)
 285 {
 286         errcode_t retval;
 287         blk64_t val;
 288         retval = ext2fs_get_free_blocks2(fs, start, finish, num, map, &val);
 289         if(!retval)
 290                 *ret = (blk_t) val;
 291         return retval;
 292 }
 293
 294 void ext2fs_set_alloc_block_callback(ext2_filsys fs,
 295                                      errcode_t (*func)(ext2_filsys fs,
 296                                                        blk64_t goal,
 297                                                        blk64_t *ret),
 298                                      errcode_t (**old)(ext2_filsys fs,
 299                                                        blk64_t goal,
 300                                                        blk64_t *ret))
 301 {
 302         if (!fs || fs->magic != EXT2_ET_MAGIC_EXT2FS_FILSYS)
 303                 return;
 304
 305         if (old)
 306                 *old = fs->get_alloc_block;
 307
 308         fs->get_alloc_block = func;
 309 }