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                            int elem_size)
  39 {
  40         int             flexbg, flexbg_size;
  41         blk_t           last_blk, first_free = 0;
  42         dgrp_t          last_grp;
  43
  44         flexbg_size = 1 << fs->super->s_log_groups_per_flex;
  45         flexbg = group / flexbg_size;
  46
  47         if (size > (int) (fs->super->s_blocks_per_group / 8))
  48                 size = (int) fs->super->s_blocks_per_group / 8;
  49
  50         if (offset)
  51                 offset -= 1;
  52
  53         /*
  54          * Don't do a long search if the previous block
  55          * search is still valid.
  56          */
  57         if (start_blk && group % flexbg_size) {
  58                 if (ext2fs_test_block_bitmap_range(bmap, start_blk + elem_size,
  59                                                    size))
  60                         return start_blk + elem_size;
  61         }
  62
  63         start_blk = ext2fs_group_first_block(fs, flexbg_size * flexbg);
  64         last_grp = group | (flexbg_size - 1);
  65         if (last_grp > fs->group_desc_count)
  66                 last_grp = fs->group_desc_count;
  67         last_blk = ext2fs_group_last_block(fs, last_grp);
  68
  69         /* Find the first available block */
  70         if (ext2fs_get_free_blocks(fs, start_blk, last_blk, 1, bmap,
  71                                    &first_free))
  72                 return first_free;
  73
  74         if (ext2fs_get_free_blocks(fs, first_free + offset, last_blk, size,
  75                                    bmap, &first_free))
  76                 return first_free;
  77
  78         return first_free;
  79 }
  80
  81 errcode_t ext2fs_allocate_group_table(ext2_filsys fs, dgrp_t group,
  82                                       ext2fs_block_bitmap bmap)
  83 {
  84         errcode_t       retval;
  85         blk_t           group_blk, start_blk, last_blk, new_blk, blk;
  86         dgrp_t          last_grp = 0;
  87         int             j, rem_grps = 0, flexbg_size = 0;
  88
  89         group_blk = ext2fs_group_first_block(fs, group);
  90         last_blk = ext2fs_group_last_block(fs, group);
  91
  92         if (!bmap)
  93                 bmap = fs->block_map;
  94
  95         if (EXT2_HAS_INCOMPAT_FEATURE(fs->super,
  96                                       EXT4_FEATURE_INCOMPAT_FLEX_BG) &&
  97             fs->super->s_log_groups_per_flex) {
  98                 flexbg_size = 1 << fs->super->s_log_groups_per_flex;
  99                 last_grp = group | (flexbg_size - 1);
 100                 rem_grps = last_grp - group;
 101                 if (last_grp > fs->group_desc_count)
 102                         last_grp = fs->group_desc_count;
 103         }
 104
 105         /*
 106          * Allocate the block and inode bitmaps, if necessary
 107          */
 108         if (fs->stride) {
 109                 retval = ext2fs_get_free_blocks(fs, group_blk, last_blk,
 110                                                 1, bmap, &start_blk);
 111                 if (retval)
 112                         return retval;
 113                 start_blk += fs->inode_blocks_per_group;
 114                 start_blk += ((fs->stride * group) %
 115                               (last_blk - start_blk + 1));
 116                 if (start_blk >= last_blk)
 117                         start_blk = group_blk;
 118         } else
 119                 start_blk = group_blk;
 120
 121         if (flexbg_size) {
 122                 blk_t prev_block = 0;
 123                 if (group && fs->group_desc[group-1].bg_block_bitmap)
 124                         prev_block = fs->group_desc[group-1].bg_block_bitmap;
 125                 start_blk = flexbg_offset(fs, group, prev_block, bmap,
 126                                                  0, rem_grps, 1);
 127                 last_blk = ext2fs_group_last_block(fs, last_grp);
 128         }
 129
 130         if (!fs->group_desc[group].bg_block_bitmap) {
 131                 retval = ext2fs_get_free_blocks(fs, start_blk, last_blk,
 132                                                 1, bmap, &new_blk);
 133                 if (retval == EXT2_ET_BLOCK_ALLOC_FAIL)
 134                         retval = ext2fs_get_free_blocks(fs, group_blk,
 135                                         last_blk, 1, bmap, &new_blk);
 136                 if (retval)
 137                         return retval;
 138                 ext2fs_mark_block_bitmap(bmap, new_blk);
 139                 fs->group_desc[group].bg_block_bitmap = new_blk;
 140                 if (flexbg_size) {
 141                         dgrp_t gr = ext2fs_group_of_blk(fs, new_blk);
 142                         fs->group_desc[gr].bg_free_blocks_count--;
 143                         fs->super->s_free_blocks_count--;
 144                         fs->group_desc[gr].bg_flags &= ~EXT2_BG_BLOCK_UNINIT;
 145                         ext2fs_group_desc_csum_set(fs, gr);
 146                 }
 147         }
 148
 149         if (flexbg_size) {
 150                 blk_t prev_block = 0;
 151                 if (group && fs->group_desc[group-1].bg_inode_bitmap)
 152                         prev_block = fs->group_desc[group-1].bg_inode_bitmap;
 153                 start_blk = flexbg_offset(fs, group, prev_block, bmap,
 154                                                  flexbg_size, rem_grps, 1);
 155                 last_blk = ext2fs_group_last_block(fs, last_grp);
 156         }
 157
 158         if (!fs->group_desc[group].bg_inode_bitmap) {
 159                 retval = ext2fs_get_free_blocks(fs, start_blk, last_blk,
 160                                                 1, bmap, &new_blk);
 161                 if (retval == EXT2_ET_BLOCK_ALLOC_FAIL)
 162                         retval = ext2fs_get_free_blocks(fs, group_blk,
 163                                         last_blk, 1, bmap, &new_blk);
 164                 if (retval)
 165                         return retval;
 166                 ext2fs_mark_block_bitmap(bmap, new_blk);
 167                 fs->group_desc[group].bg_inode_bitmap = new_blk;
 168                 if (flexbg_size) {
 169                         dgrp_t gr = ext2fs_group_of_blk(fs, new_blk);
 170                         fs->group_desc[gr].bg_free_blocks_count--;
 171                         fs->super->s_free_blocks_count--;
 172                         fs->group_desc[gr].bg_flags &= ~EXT2_BG_BLOCK_UNINIT;
 173                         ext2fs_group_desc_csum_set(fs, gr);
 174                 }
 175         }
 176
 177         /*
 178          * Allocate the inode table
 179          */
 180         if (flexbg_size) {
 181                 int prev_block = 0;
 182                 if (group && fs->group_desc[group-1].bg_inode_table)
 183                         prev_block = fs->group_desc[group-1].bg_inode_table;
 184                 group_blk = flexbg_offset(fs, group, prev_block, bmap,
 185                                                  flexbg_size * 2,
 186                                                  fs->inode_blocks_per_group *
 187                                                  rem_grps,
 188                                                  fs->inode_blocks_per_group);
 189                 last_blk = ext2fs_group_last_block(fs, last_grp);
 190         }
 191
 192         if (!fs->group_desc[group].bg_inode_table) {
 193                 retval = ext2fs_get_free_blocks(fs, group_blk, last_blk,
 194                                                 fs->inode_blocks_per_group,
 195                                                 bmap, &new_blk);
 196                 if (retval)
 197                         return retval;
 198                 for (j=0, blk = new_blk;
 199                      j < fs->inode_blocks_per_group;
 200                      j++, blk++) {
 201                         ext2fs_mark_block_bitmap(bmap, blk);
 202                         if (flexbg_size) {
 203                                 dgrp_t gr = ext2fs_group_of_blk(fs, blk);
 204                                 fs->group_desc[gr].bg_free_blocks_count--;
 205                                 fs->super->s_free_blocks_count--;
 206                                 fs->group_desc[gr].bg_flags &= ~EXT2_BG_BLOCK_UNINIT;
 207                                 ext2fs_group_desc_csum_set(fs, gr);
 208                         }
 209                 }
 210                 fs->group_desc[group].bg_inode_table = new_blk;
 211         }
 212         ext2fs_group_desc_csum_set(fs, group);
 213         return 0;
 214 }
 215
 216 errcode_t ext2fs_allocate_tables(ext2_filsys fs)
 217 {
 218         errcode_t       retval;
 219         dgrp_t          i;
 220
 221         for (i = 0; i < fs->group_desc_count; i++) {
 222                 retval = ext2fs_allocate_group_table(fs, i, fs->block_map);
 223                 if (retval)
 224                         return retval;
 225         }
 226         return 0;
 227 }
 228