lib/ext2fs/alloc_tables.c

   1 /*
   2  * alloc_tables.c --- Allocate tables for a newly initialized
   3  * filesystem.  Used by mke2fs when initializing a filesystem
   4  *
   5  * Copyright (C) 1996 Theodore Ts'o.
   6  *
   7  * %Begin-Header%
   8  * This file may be redistributed under the terms of the GNU Public
   9  * License.
  10  * %End-Header%
  11  */
  12
  13 #include <stdio.h>
  14 #include <string.h>
  15 #if HAVE_UNISTD_H
  16 #include <unistd.h>
  17 #endif
  18 #include <fcntl.h>
  19 #include <time.h>
  20 #if HAVE_SYS_STAT_H
  21 #include <sys/stat.h>
  22 #endif
  23 #if HAVE_SYS_TYPES_H
  24 #include <sys/types.h>
  25 #endif
  26
  27 #include "ext2_fs.h"
  28 #include "ext2fs.h"
  29
  30 /*
  31  * This routine searches for free blocks that can allocate a full
  32  * group of bitmaps or inode tables for a flexbg group.  Returns the
  33  * block number with a correct offset were the bitmaps and inode
  34  * tables can be allocated continously and in order.
  35  */
  36 static blk_t flexbg_offset(ext2_filsys fs, dgrp_t group, blk_t start_blk,
  37                            ext2fs_block_bitmap bmap, int offset, int size)
  38 {
  39         int             flexbg, flexbg_size, elem_size;
  40         blk_t           last_blk, first_free = 0;
  41         dgrp_t          last_grp;
  42
  43         flexbg_size = 1 << fs->super->s_log_groups_per_flex;
  44         flexbg = group / flexbg_size;
  45
  46         if (size > (int) (fs->super->s_blocks_per_group / 8))
  47                 size = (int) fs->super->s_blocks_per_group / 8;
  48
  49         if (offset)
  50                 offset -= 1;
  51
  52         /*
  53          * Don't do a long search if the previous block
  54          * search is still valid.
  55          */
  56         if (start_blk && group % flexbg_size) {
  57                 if (size > flexbg_size)
  58                         elem_size = fs->inode_blocks_per_group;
  59                 else
  60                         elem_size = 1;
  61                 if (ext2fs_test_block_bitmap_range(bmap, start_blk + elem_size,
  62                                                    size))
  63                         return start_blk + elem_size;
  64         }
  65
  66         start_blk = ext2fs_group_first_block(fs, flexbg_size * flexbg);
  67         last_grp = group | (flexbg_size - 1);
  68         if (last_grp > fs->group_desc_count)
  69                 last_grp = fs->group_desc_count;
  70         last_blk = ext2fs_group_last_block(fs, last_grp);
  71
  72         /* Find the first available block */
  73         if (ext2fs_get_free_blocks(fs, start_blk, last_blk, 1, bmap,
  74                                    &first_free))
  75                 return first_free;
  76
  77         if (ext2fs_get_free_blocks(fs, first_free + offset, last_blk, size,
  78                                    bmap, &first_free))
  79                 return first_free;
  80
  81         return first_free;
  82 }
  83
  84 errcode_t ext2fs_allocate_group_table(ext2_filsys fs, dgrp_t group,
  85                                       ext2fs_block_bitmap bmap)
  86 {
  87         errcode_t       retval;
  88         blk_t           group_blk, start_blk, last_blk, new_blk, blk;
  89         dgrp_t          last_grp = 0;
  90         int             j, rem_grps = 0, flexbg_size = 0;
  91
  92         group_blk = ext2fs_group_first_block(fs, group);
  93         last_blk = ext2fs_group_last_block(fs, group);
  94
  95         if (!bmap)
  96                 bmap = fs->block_map;
  97
  98         if (EXT2_HAS_INCOMPAT_FEATURE(fs->super,
  99                                       EXT4_FEATURE_INCOMPAT_FLEX_BG) &&
 100             fs->super->s_log_groups_per_flex) {
 101                 flexbg_size = 1 << fs->super->s_log_groups_per_flex;
 102                 last_grp = group | (flexbg_size - 1);
 103                 rem_grps = last_grp - group;
 104                 if (last_grp > fs->group_desc_count)
 105                         last_grp = fs->group_desc_count;
 106         }
 107
 108         /*
 109          * Allocate the block and inode bitmaps, if necessary
 110          */
 111         if (fs->stride) {
 112                 retval = ext2fs_get_free_blocks(fs, group_blk, last_blk,
 113                                                 1, bmap, &start_blk);
 114                 if (retval)
 115                         return retval;
 116                 start_blk += fs->inode_blocks_per_group;
 117                 start_blk += ((fs->stride * group) %
 118                               (last_blk - start_blk + 1));
 119                 if (start_blk >= last_blk)
 120                         start_blk = group_blk;
 121         } else
 122                 start_blk = group_blk;
 123
 124         if (flexbg_size) {
 125                 int prev_block = 0;
 126                 if (group && fs->group_desc[group-1].bg_block_bitmap)
 127                         prev_block = fs->group_desc[group-1].bg_block_bitmap;
 128                 start_blk = flexbg_offset(fs, group, prev_block, bmap,
 129                                                  0, rem_grps);
 130                 last_blk = ext2fs_group_last_block(fs, last_grp);
 131         }
 132
 133         if (!fs->group_desc[group].bg_block_bitmap) {
 134                 retval = ext2fs_get_free_blocks(fs, start_blk, last_blk,
 135                                                 1, bmap, &new_blk);
 136                 if (retval == EXT2_ET_BLOCK_ALLOC_FAIL)
 137                         retval = ext2fs_get_free_blocks(fs, group_blk,
 138                                         last_blk, 1, bmap, &new_blk);
 139                 if (retval)
 140                         return retval;
 141                 ext2fs_mark_block_bitmap(bmap, new_blk);
 142                 fs->group_desc[group].bg_block_bitmap = new_blk;
 143                 if (flexbg_size) {
 144                         dgrp_t gr = ext2fs_group_of_blk(fs, new_blk);
 145                         fs->group_desc[gr].bg_free_blocks_count--;
 146                         fs->super->s_free_blocks_count--;
 147                         fs->group_desc[gr].bg_flags &= ~EXT2_BG_BLOCK_UNINIT;
 148                         ext2fs_group_desc_csum_set(fs, gr);
 149                 }
 150         }
 151
 152         if (flexbg_size) {
 153                 int prev_block = 0;
 154                 if (group && fs->group_desc[group-1].bg_inode_bitmap)
 155                         prev_block = fs->group_desc[group-1].bg_inode_bitmap;
 156                 start_blk = flexbg_offset(fs, group, prev_block, bmap,
 157                                                  flexbg_size, rem_grps);
 158                 last_blk = ext2fs_group_last_block(fs, last_grp);
 159         }
 160
 161         if (!fs->group_desc[group].bg_inode_bitmap) {
 162                 retval = ext2fs_get_free_blocks(fs, start_blk, last_blk,
 163                                                 1, bmap, &new_blk);
 164                 if (retval == EXT2_ET_BLOCK_ALLOC_FAIL)
 165                         retval = ext2fs_get_free_blocks(fs, group_blk,
 166                                         last_blk, 1, bmap, &new_blk);
 167                 if (retval)
 168                         return retval;
 169                 ext2fs_mark_block_bitmap(bmap, new_blk);
 170                 fs->group_desc[group].bg_inode_bitmap = new_blk;
 171                 if (flexbg_size) {
 172                         dgrp_t gr = ext2fs_group_of_blk(fs, new_blk);
 173                         fs->group_desc[gr].bg_free_blocks_count--;
 174                         fs->super->s_free_blocks_count--;
 175                         fs->group_desc[gr].bg_flags &= ~EXT2_BG_BLOCK_UNINIT;
 176                         ext2fs_group_desc_csum_set(fs, gr);
 177                 }
 178         }
 179
 180         /*
 181          * Allocate the inode table
 182          */
 183         if (flexbg_size) {
 184                 int prev_block = 0;
 185                 if (group && fs->group_desc[group-1].bg_inode_table)
 186                         prev_block = fs->group_desc[group-1].bg_inode_table;
 187                 group_blk = flexbg_offset(fs, group, prev_block, bmap,
 188                                                  flexbg_size * 2,
 189                                                  fs->inode_blocks_per_group *
 190                                                  rem_grps);
 191                 last_blk = ext2fs_group_last_block(fs, last_grp);
 192         }
 193
 194         if (!fs->group_desc[group].bg_inode_table) {
 195                 retval = ext2fs_get_free_blocks(fs, group_blk, last_blk,
 196                                                 fs->inode_blocks_per_group,
 197                                                 bmap, &new_blk);
 198                 if (retval)
 199                         return retval;
 200                 for (j=0, blk = new_blk;
 201                      j < fs->inode_blocks_per_group;
 202                      j++, blk++) {
 203                         ext2fs_mark_block_bitmap(bmap, blk);
 204                         if (flexbg_size) {
 205                                 dgrp_t gr = ext2fs_group_of_blk(fs, blk);
 206                                 fs->group_desc[gr].bg_free_blocks_count--;
 207                                 fs->super->s_free_blocks_count--;
 208                                 fs->group_desc[gr].bg_flags &= ~EXT2_BG_BLOCK_UNINIT;
 209                                 ext2fs_group_desc_csum_set(fs, gr);
 210                         }
 211                 }
 212                 fs->group_desc[group].bg_inode_table = new_blk;
 213         }
 214         ext2fs_group_desc_csum_set(fs, group);
 215         return 0;
 216 }
 217
 218 errcode_t ext2fs_allocate_tables(ext2_filsys fs)
 219 {
 220         errcode_t       retval;
 221         dgrp_t          i;
 222
 223         for (i = 0; i < fs->group_desc_count; i++) {
 224                 retval = ext2fs_allocate_group_table(fs, i, fs->block_map);
 225                 if (retval)
 226                         return retval;
 227         }
 228         return 0;
 229 }
 230