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 "config.h"
  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             !(ext2fs_bg_flags_test(fs, group, 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                 ext2fs_fast_unmark_block_bitmap2(map, blk);
  58
  59         blk = (group * fs->super->s_blocks_per_group) +
  60                 fs->super->s_first_data_block;
  61         for (i=0; i < fs->super->s_blocks_per_group; i++, blk++) {
  62                 if ((blk == super_blk) ||
  63                     (old_desc_blk && old_desc_blocks &&
  64                      (blk >= old_desc_blk) &&
  65                      (blk < old_desc_blk + old_desc_blocks)) ||
  66                     (new_desc_blk && (blk == new_desc_blk)) ||
  67                     (blk == ext2fs_block_bitmap_loc(fs, group)) ||
  68                     (blk == ext2fs_inode_bitmap_loc(fs, group)) ||
  69                     (blk >= ext2fs_inode_table_loc(fs, group) &&
  70                      (blk < ext2fs_inode_table_loc(fs, group)
  71                       + fs->inode_blocks_per_group)))
  72                         ext2fs_fast_mark_block_bitmap2(map, blk);
  73         }
  74         ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
  75         ext2fs_group_desc_csum_set(fs, group);
  76 }
  77
  78 /*
  79  * Check for uninit inode bitmaps and deal with them appropriately
  80  */
  81 static void check_inode_uninit(ext2_filsys fs, ext2fs_inode_bitmap map,
  82                           dgrp_t group)
  83 {
  84         ext2_ino_t      i, ino;
  85
  86         if (!(EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
  87                                          EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) ||
  88             !(ext2fs_bg_flags_test(fs, group, EXT2_BG_INODE_UNINIT)))
  89                 return;
  90
  91         ino = (group * fs->super->s_inodes_per_group) + 1;
  92         for (i=0; i < fs->super->s_inodes_per_group; i++, ino++)
  93                 ext2fs_fast_unmark_inode_bitmap2(map, ino);
  94
  95         ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT);
  96         check_block_uninit(fs, fs->block_map, group);
  97 }
  98
  99 /*
 100  * Right now, just search forward from the parent directory's block
 101  * group to find the next free inode.
 102  *
 103  * Should have a special policy for directories.
 104  */
 105 errcode_t ext2fs_new_inode(ext2_filsys fs, ext2_ino_t dir,
 106                            int mode EXT2FS_ATTR((unused)),
 107                            ext2fs_inode_bitmap map, ext2_ino_t *ret)
 108 {
 109         ext2_ino_t      dir_group = 0;
 110         ext2_ino_t      i;
 111         ext2_ino_t      start_inode;
 112
 113         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 114
 115         if (!map)
 116                 map = fs->inode_map;
 117         if (!map)
 118                 return EXT2_ET_NO_INODE_BITMAP;
 119
 120         if (dir > 0)
 121                 dir_group = (dir - 1) / EXT2_INODES_PER_GROUP(fs->super);
 122
 123         start_inode = (dir_group * EXT2_INODES_PER_GROUP(fs->super)) + 1;
 124         if (start_inode < EXT2_FIRST_INODE(fs->super))
 125                 start_inode = EXT2_FIRST_INODE(fs->super);
 126         if (start_inode > fs->super->s_inodes_count)
 127                 return EXT2_ET_INODE_ALLOC_FAIL;
 128         i = start_inode;
 129
 130         do {
 131                 if (((i - 1) % EXT2_INODES_PER_GROUP(fs->super)) == 0)
 132                         check_inode_uninit(fs, map, (i - 1) /
 133                                            EXT2_INODES_PER_GROUP(fs->super));
 134
 135                 if (!ext2fs_fast_test_inode_bitmap2(map, i))
 136                         break;
 137                 i++;
 138                 if (i > fs->super->s_inodes_count)
 139                         i = EXT2_FIRST_INODE(fs->super);
 140         } while (i != start_inode);
 141
 142         if (ext2fs_test_inode_bitmap2(map, i))
 143                 return EXT2_ET_INODE_ALLOC_FAIL;
 144         *ret = i;
 145         return 0;
 146 }
 147
 148 /*
 149  * Stupid algorithm --- we now just search forward starting from the
 150  * goal.  Should put in a smarter one someday....
 151  */
 152 errcode_t ext2fs_new_block2(ext2_filsys fs, blk64_t goal,
 153                            ext2fs_block_bitmap map, blk64_t *ret)
 154 {
 155         blk64_t i;
 156         int     c_ratio;
 157
 158         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 159
 160         if (!map)
 161                 map = fs->block_map;
 162         if (!map)
 163                 return EXT2_ET_NO_BLOCK_BITMAP;
 164         if (!goal || (goal >= ext2fs_blocks_count(fs->super)))
 165                 goal = fs->super->s_first_data_block;
 166         i = goal;
 167         c_ratio = 1 << ext2fs_get_bitmap_granularity(map);
 168         if (c_ratio > 1)
 169                 goal &= ~EXT2FS_CLUSTER_MASK(fs);
 170         check_block_uninit(fs, map,
 171                            (i - fs->super->s_first_data_block) /
 172                            EXT2_BLOCKS_PER_GROUP(fs->super));
 173         do {
 174                 if (((i - fs->super->s_first_data_block) %
 175                      EXT2_BLOCKS_PER_GROUP(fs->super)) == 0)
 176                         check_block_uninit(fs, map,
 177                                            (i - fs->super->s_first_data_block) /
 178                                            EXT2_BLOCKS_PER_GROUP(fs->super));
 179
 180                 if (!ext2fs_fast_test_block_bitmap2(map, i)) {
 181                         *ret = i;
 182                         return 0;
 183                 }
 184                 i = (i + c_ratio) & ~(c_ratio - 1);
 185                 if (i >= ext2fs_blocks_count(fs->super))
 186                         i = fs->super->s_first_data_block;
 187         } while (i != goal);
 188         return EXT2_ET_BLOCK_ALLOC_FAIL;
 189 }
 190
 191 errcode_t ext2fs_new_block(ext2_filsys fs, blk_t goal,
 192                            ext2fs_block_bitmap map, blk_t *ret)
 193 {
 194         errcode_t retval;
 195         blk64_t val;
 196         retval = ext2fs_new_block2(fs, goal, map, &val);
 197         if (!retval)
 198                 *ret = (blk_t) val;
 199         return retval;
 200 }
 201
 202 /*
 203  * This function zeros out the allocated block, and updates all of the
 204  * appropriate filesystem records.
 205  */
 206 errcode_t ext2fs_alloc_block2(ext2_filsys fs, blk64_t goal,
 207                              char *block_buf, blk64_t *ret)
 208 {
 209         errcode_t       retval;
 210         blk64_t         block;
 211         char            *buf = 0;
 212
 213         if (!block_buf) {
 214                 retval = ext2fs_get_mem(fs->blocksize, &buf);
 215                 if (retval)
 216                         return retval;
 217                 block_buf = buf;
 218         }
 219         memset(block_buf, 0, fs->blocksize);
 220
 221         if (fs->get_alloc_block) {
 222                 retval = (fs->get_alloc_block)(fs, goal, &block);
 223                 if (retval)
 224                         goto fail;
 225         } else {
 226                 if (!fs->block_map) {
 227                         retval = ext2fs_read_block_bitmap(fs);
 228                         if (retval)
 229                                 goto fail;
 230                 }
 231
 232                 retval = ext2fs_new_block2(fs, goal, 0, &block);
 233                 if (retval)
 234                         goto fail;
 235         }
 236
 237         retval = io_channel_write_blk64(fs->io, block, 1, block_buf);
 238         if (retval)
 239                 goto fail;
 240
 241         ext2fs_block_alloc_stats2(fs, block, +1);
 242         *ret = block;
 243
 244 fail:
 245         if (buf)
 246                 ext2fs_free_mem(&buf);
 247         return retval;
 248 }
 249
 250 errcode_t ext2fs_alloc_block(ext2_filsys fs, blk_t goal,
 251                              char *block_buf, blk_t *ret)
 252 {
 253         errcode_t retval;
 254         blk64_t val;
 255         retval = ext2fs_alloc_block2(fs, goal, block_buf, &val);
 256         if (!retval)
 257                 *ret = (blk_t) val;
 258         return retval;
 259 }
 260
 261 errcode_t ext2fs_get_free_blocks2(ext2_filsys fs, blk64_t start, blk64_t finish,
 262                                  int num, ext2fs_block_bitmap map, blk64_t *ret)
 263 {
 264         blk64_t b = start;
 265         int     c_ratio;
 266
 267         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 268
 269         if (!map)
 270                 map = fs->block_map;
 271         if (!map)
 272                 return EXT2_ET_NO_BLOCK_BITMAP;
 273         if (!b)
 274                 b = fs->super->s_first_data_block;
 275         if (!finish)
 276                 finish = start;
 277         if (!num)
 278                 num = 1;
 279         c_ratio = 1 << ext2fs_get_bitmap_granularity(map);
 280         b &= ~(c_ratio - 1);
 281         finish &= ~(c_ratio -1);
 282         do {
 283                 if (b+num-1 > ext2fs_blocks_count(fs->super))
 284                         b = fs->super->s_first_data_block;
 285                 if (ext2fs_fast_test_block_bitmap_range2(map, b, num)) {
 286                         *ret = b;
 287                         return 0;
 288                 }
 289                 b += c_ratio;
 290         } while (b != finish);
 291         return EXT2_ET_BLOCK_ALLOC_FAIL;
 292 }
 293
 294 errcode_t ext2fs_get_free_blocks(ext2_filsys fs, blk_t start, blk_t finish,
 295                                  int num, ext2fs_block_bitmap map, blk_t *ret)
 296 {
 297         errcode_t retval;
 298         blk64_t val;
 299         retval = ext2fs_get_free_blocks2(fs, start, finish, num, map, &val);
 300         if(!retval)
 301                 *ret = (blk_t) val;
 302         return retval;
 303 }
 304
 305 void ext2fs_set_alloc_block_callback(ext2_filsys fs,
 306                                      errcode_t (*func)(ext2_filsys fs,
 307                                                        blk64_t goal,
 308                                                        blk64_t *ret),
 309                                      errcode_t (**old)(ext2_filsys fs,
 310                                                        blk64_t goal,
 311                                                        blk64_t *ret))
 312 {
 313         if (!fs || fs->magic != EXT2_ET_MAGIC_EXT2FS_FILSYS)
 314                 return;
 315
 316         if (old)
 317                 *old = fs->get_alloc_block;
 318
 319         fs->get_alloc_block = func;
 320 }