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 Library
   8  * General Public License, version 2.
   9  * %End-Header%
  10  */
  11
  12 #include <stdio.h>
  13 #if HAVE_UNISTD_H
  14 #include <unistd.h>
  15 #endif
  16 #include <time.h>
  17 #include <string.h>
  18 #if HAVE_SYS_STAT_H
  19 #include <sys/stat.h>
  20 #endif
  21 #if HAVE_SYS_TYPES_H
  22 #include <sys/types.h>
  23 #endif
  24
  25 #include "ext2_fs.h"
  26 #include "ext2fs.h"
  27
  28 /*
  29  * Check for uninit block bitmaps and deal with them appropriately
  30  */
  31 static void check_block_uninit(ext2_filsys fs, ext2fs_block_bitmap map,
  32                                dgrp_t group)
  33 {
  34         blk_t           i;
  35         blk64_t         blk, super_blk, old_desc_blk, new_desc_blk;
  36         int             old_desc_blocks;
  37
  38         if (!(EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
  39                                          EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) ||
  40             !(ext2fs_bg_flags_test(fs, group, EXT2_BG_BLOCK_UNINIT)))
  41                 return;
  42
  43         blk = (group * fs->super->s_blocks_per_group) +
  44                 fs->super->s_first_data_block;
  45
  46         ext2fs_super_and_bgd_loc2(fs, group, &super_blk,
  47                                   &old_desc_blk, &new_desc_blk, 0);
  48
  49         if (fs->super->s_feature_incompat &
  50             EXT2_FEATURE_INCOMPAT_META_BG)
  51                 old_desc_blocks = fs->super->s_first_meta_bg;
  52         else
  53                 old_desc_blocks = fs->desc_blocks + fs->super->s_reserved_gdt_blocks;
  54
  55         for (i=0; i < fs->super->s_blocks_per_group; i++, blk++) {
  56                 if ((blk == super_blk) ||
  57                     (old_desc_blk && old_desc_blocks &&
  58                      (blk >= old_desc_blk) &&
  59                      (blk < old_desc_blk + old_desc_blocks)) ||
  60                     (new_desc_blk && (blk == new_desc_blk)) ||
  61                     (blk == ext2fs_block_bitmap_loc(fs, group)) ||
  62                     (blk == ext2fs_inode_bitmap_loc(fs, group)) ||
  63                     (blk >= ext2fs_inode_table_loc(fs, group) &&
  64                      (blk < ext2fs_inode_table_loc(fs, group)
  65                       + fs->inode_blocks_per_group)))
  66                         ext2fs_fast_mark_block_bitmap2(map, blk);
  67                 else
  68                         ext2fs_fast_unmark_block_bitmap2(map, blk);
  69         }
  70         ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
  71         ext2fs_group_desc_csum_set(fs, group);
  72 }
  73
  74 /*
  75  * Check for uninit inode bitmaps and deal with them appropriately
  76  */
  77 static void check_inode_uninit(ext2_filsys fs, ext2fs_inode_bitmap map,
  78                           dgrp_t group)
  79 {
  80         ext2_ino_t      i, ino;
  81
  82         if (!(EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
  83                                          EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) ||
  84             !(ext2fs_bg_flags_test(fs, group, EXT2_BG_INODE_UNINIT)))
  85                 return;
  86
  87         ino = (group * fs->super->s_inodes_per_group) + 1;
  88         for (i=0; i < fs->super->s_inodes_per_group; i++, ino++)
  89                 ext2fs_fast_unmark_inode_bitmap2(map, ino);
  90
  91         ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT);
  92         check_block_uninit(fs, fs->block_map, group);
  93 }
  94
  95 /*
  96  * Right now, just search forward from the parent directory's block
  97  * group to find the next free inode.
  98  *
  99  * Should have a special policy for directories.
 100  */
 101 errcode_t ext2fs_new_inode(ext2_filsys fs, ext2_ino_t dir,
 102                            int mode EXT2FS_ATTR((unused)),
 103                            ext2fs_inode_bitmap map, ext2_ino_t *ret)
 104 {
 105         ext2_ino_t      dir_group = 0;
 106         ext2_ino_t      i;
 107         ext2_ino_t      start_inode;
 108
 109         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 110
 111         if (!map)
 112                 map = fs->inode_map;
 113         if (!map)
 114                 return EXT2_ET_NO_INODE_BITMAP;
 115
 116         if (dir > 0)
 117                 dir_group = (dir - 1) / EXT2_INODES_PER_GROUP(fs->super);
 118
 119         start_inode = (dir_group * EXT2_INODES_PER_GROUP(fs->super)) + 1;
 120         if (start_inode < EXT2_FIRST_INODE(fs->super))
 121                 start_inode = EXT2_FIRST_INODE(fs->super);
 122         if (start_inode > fs->super->s_inodes_count)
 123                 return EXT2_ET_INODE_ALLOC_FAIL;
 124         i = start_inode;
 125
 126         do {
 127                 if (((i - 1) % EXT2_INODES_PER_GROUP(fs->super)) == 0)
 128                         check_inode_uninit(fs, map, (i - 1) /
 129                                            EXT2_INODES_PER_GROUP(fs->super));
 130
 131                 if (!ext2fs_fast_test_inode_bitmap2(map, i))
 132                         break;
 133                 i++;
 134                 if (i > fs->super->s_inodes_count)
 135                         i = EXT2_FIRST_INODE(fs->super);
 136         } while (i != start_inode);
 137
 138         if (ext2fs_test_inode_bitmap2(map, i))
 139                 return EXT2_ET_INODE_ALLOC_FAIL;
 140         *ret = i;
 141         return 0;
 142 }
 143
 144 /*
 145  * Stupid algorithm --- we now just search forward starting from the
 146  * goal.  Should put in a smarter one someday....
 147  */
 148 errcode_t ext2fs_new_block2(ext2_filsys fs, blk64_t goal,
 149                            ext2fs_block_bitmap map, blk64_t *ret)
 150 {
 151         blk64_t i;
 152
 153         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 154
 155         if (!map)
 156                 map = fs->block_map;
 157         if (!map)
 158                 return EXT2_ET_NO_BLOCK_BITMAP;
 159         if (!goal || (goal >= ext2fs_blocks_count(fs->super)))
 160                 goal = fs->super->s_first_data_block;
 161         i = goal;
 162         check_block_uninit(fs, map,
 163                            (i - fs->super->s_first_data_block) /
 164                            EXT2_BLOCKS_PER_GROUP(fs->super));
 165         do {
 166                 if (((i - fs->super->s_first_data_block) %
 167                      EXT2_BLOCKS_PER_GROUP(fs->super)) == 0)
 168                         check_block_uninit(fs, map,
 169                                            (i - fs->super->s_first_data_block) /
 170                                            EXT2_BLOCKS_PER_GROUP(fs->super));
 171
 172                 if (!ext2fs_fast_test_block_bitmap2(map, i)) {
 173                         *ret = i;
 174                         return 0;
 175                 }
 176                 i++;
 177                 if (i >= ext2fs_blocks_count(fs->super))
 178                         i = fs->super->s_first_data_block;
 179         } while (i != goal);
 180         return EXT2_ET_BLOCK_ALLOC_FAIL;
 181 }
 182
 183 errcode_t ext2fs_new_block(ext2_filsys fs, blk_t goal,
 184                            ext2fs_block_bitmap map, blk_t *ret)
 185 {
 186         errcode_t retval;
 187         blk64_t val;
 188         retval = ext2fs_new_block2(fs, goal, map, &val);
 189         if (!retval)
 190                 *ret = (blk_t) val;
 191         return retval;
 192 }
 193
 194 /*
 195  * This function zeros out the allocated block, and updates all of the
 196  * appropriate filesystem records.
 197  */
 198 errcode_t ext2fs_alloc_block2(ext2_filsys fs, blk64_t goal,
 199                              char *block_buf, blk64_t *ret)
 200 {
 201         errcode_t       retval;
 202         blk64_t         block;
 203         char            *buf = 0;
 204
 205         if (!block_buf) {
 206                 retval = ext2fs_get_mem(fs->blocksize, &buf);
 207                 if (retval)
 208                         return retval;
 209                 block_buf = buf;
 210         }
 211         memset(block_buf, 0, fs->blocksize);
 212
 213         if (fs->get_alloc_block) {
 214                 retval = (fs->get_alloc_block)(fs, goal, &block);
 215                 if (retval)
 216                         goto fail;
 217         } else {
 218                 if (!fs->block_map) {
 219                         retval = ext2fs_read_block_bitmap(fs);
 220                         if (retval)
 221                                 goto fail;
 222                 }
 223
 224                 retval = ext2fs_new_block2(fs, goal, 0, &block);
 225                 if (retval)
 226                         goto fail;
 227         }
 228
 229         retval = io_channel_write_blk64(fs->io, block, 1, block_buf);
 230         if (retval)
 231                 goto fail;
 232
 233         ext2fs_block_alloc_stats2(fs, block, +1);
 234         *ret = block;
 235
 236 fail:
 237         if (buf)
 238                 ext2fs_free_mem(&buf);
 239         return retval;
 240 }
 241
 242 errcode_t ext2fs_alloc_block(ext2_filsys fs, blk_t goal,
 243                              char *block_buf, blk_t *ret)
 244 {
 245         errcode_t retval;
 246         blk64_t val;
 247         retval = ext2fs_alloc_block2(fs, goal, block_buf, &val);
 248         if (!retval)
 249                 *ret = (blk_t) val;
 250         return retval;
 251 }
 252
 253 errcode_t ext2fs_get_free_blocks2(ext2_filsys fs, blk64_t start, blk64_t finish,
 254                                  int num, ext2fs_block_bitmap map, blk64_t *ret)
 255 {
 256         blk64_t b = start;
 257
 258         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 259
 260         if (!map)
 261                 map = fs->block_map;
 262         if (!map)
 263                 return EXT2_ET_NO_BLOCK_BITMAP;
 264         if (!b)
 265                 b = fs->super->s_first_data_block;
 266         if (!finish)
 267                 finish = start;
 268         if (!num)
 269                 num = 1;
 270         do {
 271                 if (b+num-1 > ext2fs_blocks_count(fs->super))
 272                         b = fs->super->s_first_data_block;
 273                 if (ext2fs_fast_test_block_bitmap_range2(map, b, num)) {
 274                         *ret = b;
 275                         return 0;
 276                 }
 277                 b++;
 278         } while (b != finish);
 279         return EXT2_ET_BLOCK_ALLOC_FAIL;
 280 }
 281
 282 errcode_t ext2fs_get_free_blocks(ext2_filsys fs, blk_t start, blk_t finish,
 283                                  int num, ext2fs_block_bitmap map, blk_t *ret)
 284 {
 285         errcode_t retval;
 286         blk64_t val;
 287         retval = ext2fs_get_free_blocks2(fs, start, finish, num, map, &val);
 288         if(!retval)
 289                 *ret = (blk_t) val;
 290         return retval;
 291 }
 292
 293 void ext2fs_set_alloc_block_callback(ext2_filsys fs,
 294                                      errcode_t (*func)(ext2_filsys fs,
 295                                                        blk64_t goal,
 296                                                        blk64_t *ret),
 297                                      errcode_t (**old)(ext2_filsys fs,
 298                                                        blk64_t goal,
 299                                                        blk64_t *ret))
 300 {
 301         if (!fs || fs->magic != EXT2_ET_MAGIC_EXT2FS_FILSYS)
 302                 return;
 303
 304         if (old)
 305                 *old = fs->get_alloc_block;
 306
 307         fs->get_alloc_block = func;
 308 }