fs/ext4/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 Library
   9  * General Public License, version 2.
  10  * %End-Header%
  11  */
  12
  13 #include "ext2_fs.h"
  14 #include "ext2fs.h"
  15
  16 /*
  17  * This routine searches for free blocks that can allocate a full
  18  * group of bitmaps or inode tables for a flexbg group.  Returns the
  19  * block number with a correct offset were the bitmaps and inode
  20  * tables can be allocated continously and in order.
  21  */
  22 static blk_t flexbg_offset(ext2_filsys fs, dgrp_t group, blk_t start_blk,
  23                            ext2fs_block_bitmap bmap, int offset, int size,
  24                            int elem_size)
  25 {
  26         int             flexbg, flexbg_size;
  27         blk_t           last_blk, first_free = 0;
  28         dgrp_t          last_grp;
  29
  30         flexbg_size = 1 << fs->super->s_log_groups_per_flex;
  31         flexbg = group / flexbg_size;
  32
  33         if (size > (int) (fs->super->s_blocks_per_group / 8))
  34                 size = (int) fs->super->s_blocks_per_group / 8;
  35
  36         if (offset)
  37                 offset -= 1;
  38
  39         /*
  40          * Don't do a long search if the previous block
  41          * search is still valid.
  42          */
  43         if (start_blk && group % flexbg_size) {
  44                 if (ext2fs_test_block_bitmap_range(bmap, start_blk + elem_size,
  45                                                    size))
  46                         return start_blk + elem_size;
  47         }
  48
  49         start_blk = ext2fs_group_first_block(fs, flexbg_size * flexbg);
  50         last_grp = group | (flexbg_size - 1);
  51         if (last_grp > fs->group_desc_count)
  52                 last_grp = fs->group_desc_count;
  53         last_blk = ext2fs_group_last_block(fs, last_grp);
  54
  55         /* Find the first available block */
  56         if (ext2fs_get_free_blocks(fs, start_blk, last_blk, 1, bmap,
  57                                    &first_free))
  58                 return first_free;
  59
  60         if (ext2fs_get_free_blocks(fs, first_free + offset, last_blk, size,
  61                                    bmap, &first_free))
  62                 return first_free;
  63
  64         return first_free;
  65 }
  66
  67 errcode_t ext2fs_allocate_group_table(ext2_filsys fs, dgrp_t group,
  68                                       ext2fs_block_bitmap bmap)
  69 {
  70         errcode_t       retval;
  71         blk_t           group_blk, start_blk, last_blk, new_blk, blk;
  72         dgrp_t          last_grp = 0;
  73         int             j, rem_grps = 0, flexbg_size = 0;
  74
  75         group_blk = ext2fs_group_first_block(fs, group);
  76         last_blk = ext2fs_group_last_block(fs, group);
  77
  78         if (!bmap)
  79                 bmap = fs->block_map;
  80
  81         if (EXT2_HAS_INCOMPAT_FEATURE(fs->super,
  82                                       EXT4_FEATURE_INCOMPAT_FLEX_BG) &&
  83             fs->super->s_log_groups_per_flex) {
  84                 flexbg_size = 1 << fs->super->s_log_groups_per_flex;
  85                 last_grp = group | (flexbg_size - 1);
  86                 rem_grps = last_grp - group;
  87                 if (last_grp > fs->group_desc_count)
  88                         last_grp = fs->group_desc_count;
  89         }
  90
  91         /*
  92          * Allocate the block and inode bitmaps, if necessary
  93          */
  94         if (fs->stride) {
  95                 retval = ext2fs_get_free_blocks(fs, group_blk, last_blk,
  96                                                 1, bmap, &start_blk);
  97                 if (retval)
  98                         return retval;
  99                 start_blk += fs->inode_blocks_per_group;
 100                 start_blk += ((fs->stride * group) %
 101                               (last_blk - start_blk + 1));
 102                 if (start_blk >= last_blk)
 103                         start_blk = group_blk;
 104         } else
 105                 start_blk = group_blk;
 106
 107         if (flexbg_size) {
 108                 blk_t prev_block = 0;
 109                 if (group && fs->group_desc[group-1].bg_block_bitmap)
 110                         prev_block = fs->group_desc[group-1].bg_block_bitmap;
 111
 112                 start_blk = flexbg_offset(fs, group, prev_block, bmap,
 113                                                  0, rem_grps, 1);
 114                 last_blk = ext2fs_group_last_block(fs, last_grp);
 115         }
 116
 117         if (!fs->group_desc[group].bg_block_bitmap) {
 118                 retval = ext2fs_get_free_blocks(fs, start_blk, last_blk,
 119                                                 1, bmap, &new_blk);
 120                 if (retval == EXT2_ET_BLOCK_ALLOC_FAIL)
 121                         retval = ext2fs_get_free_blocks(fs, group_blk,
 122                                         last_blk, 1, bmap, &new_blk);
 123                 if (retval)
 124                         return retval;
 125                 ext2fs_mark_block_bitmap(bmap, new_blk);
 126                 fs->group_desc[group].bg_block_bitmap = new_blk;
 127                 if (flexbg_size) {
 128                         dgrp_t gr = ext2fs_group_of_blk(fs, new_blk);
 129                         fs->group_desc[gr].bg_free_blocks_count--;
 130                         fs->super->s_free_blocks_count--;
 131                         fs->group_desc[gr].bg_flags &= ~EXT2_BG_BLOCK_UNINIT;
 132                         ext2fs_group_desc_csum_set(fs, gr);
 133                 }
 134         }
 135
 136         if (flexbg_size) {
 137                 blk_t prev_block = 0;
 138                 if (group && fs->group_desc[group-1].bg_inode_bitmap)
 139                         prev_block = fs->group_desc[group-1].bg_inode_bitmap;
 140                 start_blk = flexbg_offset(fs, group, prev_block, bmap,
 141                                                  flexbg_size, rem_grps, 1);
 142                 last_blk = ext2fs_group_last_block(fs, last_grp);
 143         }
 144
 145         if (!fs->group_desc[group].bg_inode_bitmap) {
 146                 retval = ext2fs_get_free_blocks(fs, start_blk, last_blk,
 147                                                 1, bmap, &new_blk);
 148                 if (retval == EXT2_ET_BLOCK_ALLOC_FAIL)
 149                         retval = ext2fs_get_free_blocks(fs, group_blk,
 150                                         last_blk, 1, bmap, &new_blk);
 151                 if (retval)
 152                         return retval;
 153                 ext2fs_mark_block_bitmap(bmap, new_blk);
 154                 fs->group_desc[group].bg_inode_bitmap = new_blk;
 155                 if (flexbg_size) {
 156                         dgrp_t gr = ext2fs_group_of_blk(fs, new_blk);
 157                         fs->group_desc[gr].bg_free_blocks_count--;
 158                         fs->super->s_free_blocks_count--;
 159                         fs->group_desc[gr].bg_flags &= ~EXT2_BG_BLOCK_UNINIT;
 160                         ext2fs_group_desc_csum_set(fs, gr);
 161                 }
 162         }
 163
 164         /*
 165          * Allocate the inode table
 166          */
 167         if (flexbg_size) {
 168                 blk_t prev_block = 0;
 169                 if (group && fs->group_desc[group-1].bg_inode_table)
 170                         prev_block = fs->group_desc[group-1].bg_inode_table;
 171                 if (last_grp == fs->group_desc_count)
 172                         rem_grps = last_grp - group;
 173                 group_blk = flexbg_offset(fs, group, prev_block, bmap,
 174                                                  flexbg_size * 2,
 175                                                  fs->inode_blocks_per_group *
 176                                                  rem_grps,
 177                                                  fs->inode_blocks_per_group);
 178                 last_blk = ext2fs_group_last_block(fs, last_grp);
 179         }
 180
 181         if (!fs->group_desc[group].bg_inode_table) {
 182                 retval = ext2fs_get_free_blocks(fs, group_blk, last_blk,
 183                                                 fs->inode_blocks_per_group,
 184                                                 bmap, &new_blk);
 185                 if (retval)
 186                         return retval;
 187                 for (j=0, blk = new_blk;
 188                      j < fs->inode_blocks_per_group;
 189                      j++, blk++) {
 190                         ext2fs_mark_block_bitmap(bmap, blk);
 191                         if (flexbg_size) {
 192                                 dgrp_t gr = ext2fs_group_of_blk(fs, blk);
 193                                 fs->group_desc[gr].bg_free_blocks_count--;
 194                                 fs->super->s_free_blocks_count--;
 195                                 fs->group_desc[gr].bg_flags &= ~EXT2_BG_BLOCK_UNINIT;
 196                                 ext2fs_group_desc_csum_set(fs, gr);
 197                         }
 198                 }
 199                 fs->group_desc[group].bg_inode_table = new_blk;
 200         }
 201
 202         ext2fs_group_desc_csum_set(fs, group);
 203         return 0;
 204 }
 205
 206 errcode_t ext2fs_allocate_tables(ext2_filsys fs)
 207 {
 208         errcode_t       retval;
 209         dgrp_t          i;
 210         //unsigned char *zero_buffer = (unsigned char *)xzalloc(fs->blocksize);
 211
 212         for (i = 0; i < fs->group_desc_count; i++) {
 213                 retval = ext2fs_allocate_group_table(fs, i, fs->block_map);
 214                 if (retval)
 215                         return retval;
 216 #if 0
 217         /*      Added by SISO: Not in mkfs.ext4 utility */
 218         /* Added to initialize block bitmaps and inode bitmaps to 0 */
 219
 220                 put_ext4(dev_desc, (uint64_t)(fs->group_desc[i].bg_block_bitmap * fs->blocksize),
 221                                                         zero_buffer,(uint32_t)(fs->blocksize));
 222                 put_ext4(dev_desc, (uint64_t)(fs->group_desc[i].bg_inode_bitmap * fs->blocksize),
 223                                                         zero_buffer,(uint32_t)(fs->blocksize));
 224 #endif
 225         }
 226         return 0;
 227 }
 228