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         ext2fs_mark_super_dirty(fs);
  77         ext2fs_mark_bb_dirty(fs);
  78 }
  79
  80 /*
  81  * Check for uninit inode bitmaps and deal with them appropriately
  82  */
  83 static void check_inode_uninit(ext2_filsys fs, ext2fs_inode_bitmap map,
  84                           dgrp_t group)
  85 {
  86         ext2_ino_t      i, ino;
  87
  88         if (!(EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
  89                                          EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) ||
  90             !(ext2fs_bg_flags_test(fs, group, EXT2_BG_INODE_UNINIT)))
  91                 return;
  92
  93         ino = (group * fs->super->s_inodes_per_group) + 1;
  94         for (i=0; i < fs->super->s_inodes_per_group; i++, ino++)
  95                 ext2fs_fast_unmark_inode_bitmap2(map, ino);
  96
  97         ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT);
  98         ext2fs_group_desc_csum_set(fs, group);
  99         ext2fs_mark_ib_dirty(fs);
 100         ext2fs_mark_super_dirty(fs);
 101         check_block_uninit(fs, fs->block_map, group);
 102 }
 103
 104 /*
 105  * Right now, just search forward from the parent directory's block
 106  * group to find the next free inode.
 107  *
 108  * Should have a special policy for directories.
 109  */
 110 errcode_t ext2fs_new_inode(ext2_filsys fs, ext2_ino_t dir,
 111                            int mode EXT2FS_ATTR((unused)),
 112                            ext2fs_inode_bitmap map, ext2_ino_t *ret)
 113 {
 114         ext2_ino_t      start_inode = 0;
 115         ext2_ino_t      i, ino_in_group, upto, first_zero;
 116         errcode_t       retval;
 117         dgrp_t          group;
 118
 119         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 120
 121         if (!map)
 122                 map = fs->inode_map;
 123         if (!map)
 124                 return EXT2_ET_NO_INODE_BITMAP;
 125
 126         if (dir > 0) {
 127                 group = (dir - 1) / EXT2_INODES_PER_GROUP(fs->super);
 128                 start_inode = (group * EXT2_INODES_PER_GROUP(fs->super)) + 1;
 129         }
 130         if (start_inode < EXT2_FIRST_INODE(fs->super))
 131                 start_inode = EXT2_FIRST_INODE(fs->super);
 132         if (start_inode > fs->super->s_inodes_count)
 133                 return EXT2_ET_INODE_ALLOC_FAIL;
 134         i = start_inode;
 135         do {
 136                 ino_in_group = (i - 1) % EXT2_INODES_PER_GROUP(fs->super);
 137                 group = (i - 1) / EXT2_INODES_PER_GROUP(fs->super);
 138
 139                 check_inode_uninit(fs, map, group);
 140                 upto = i + (EXT2_INODES_PER_GROUP(fs->super) - ino_in_group);
 141                 if (i < start_inode && upto >= start_inode)
 142                         upto = start_inode - 1;
 143                 if (upto > fs->super->s_inodes_count)
 144                         upto = fs->super->s_inodes_count;
 145
 146                 retval = ext2fs_find_first_zero_inode_bitmap2(map, i, upto,
 147                                                               &first_zero);
 148                 if (retval == 0) {
 149                         i = first_zero;
 150                         break;
 151                 }
 152                 if (retval != ENOENT)
 153                         return EXT2_ET_INODE_ALLOC_FAIL;
 154                 i = upto + 1;
 155                 if (i > fs->super->s_inodes_count)
 156                         i = EXT2_FIRST_INODE(fs->super);
 157         } while (i != start_inode);
 158
 159         if (ext2fs_test_inode_bitmap2(map, i))
 160                 return EXT2_ET_INODE_ALLOC_FAIL;
 161         *ret = i;
 162         return 0;
 163 }
 164
 165 /*
 166  * Stupid algorithm --- we now just search forward starting from the
 167  * goal.  Should put in a smarter one someday....
 168  */
 169 errcode_t ext2fs_new_block2(ext2_filsys fs, blk64_t goal,
 170                            ext2fs_block_bitmap map, blk64_t *ret)
 171 {
 172         blk64_t i;
 173         int     c_ratio;
 174
 175         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 176
 177         if (!map)
 178                 map = fs->block_map;
 179         if (!map)
 180                 return EXT2_ET_NO_BLOCK_BITMAP;
 181         if (!goal || (goal >= ext2fs_blocks_count(fs->super)))
 182                 goal = fs->super->s_first_data_block;
 183         i = goal;
 184         c_ratio = 1 << ext2fs_get_bitmap_granularity(map);
 185         if (c_ratio > 1)
 186                 goal &= ~EXT2FS_CLUSTER_MASK(fs);
 187         check_block_uninit(fs, map,
 188                            (i - fs->super->s_first_data_block) /
 189                            EXT2_BLOCKS_PER_GROUP(fs->super));
 190         do {
 191                 if (((i - fs->super->s_first_data_block) %
 192                      EXT2_BLOCKS_PER_GROUP(fs->super)) == 0)
 193                         check_block_uninit(fs, map,
 194                                            (i - fs->super->s_first_data_block) /
 195                                            EXT2_BLOCKS_PER_GROUP(fs->super));
 196
 197                 if (!ext2fs_fast_test_block_bitmap2(map, i)) {
 198                         *ret = i;
 199                         return 0;
 200                 }
 201                 i = (i + c_ratio) & ~(c_ratio - 1);
 202                 if (i >= ext2fs_blocks_count(fs->super))
 203                         i = fs->super->s_first_data_block;
 204         } while (i != goal);
 205         return EXT2_ET_BLOCK_ALLOC_FAIL;
 206 }
 207
 208 errcode_t ext2fs_new_block(ext2_filsys fs, blk_t goal,
 209                            ext2fs_block_bitmap map, blk_t *ret)
 210 {
 211         errcode_t retval;
 212         blk64_t val;
 213         retval = ext2fs_new_block2(fs, goal, map, &val);
 214         if (!retval)
 215                 *ret = (blk_t) val;
 216         return retval;
 217 }
 218
 219 /*
 220  * This function zeros out the allocated block, and updates all of the
 221  * appropriate filesystem records.
 222  */
 223 errcode_t ext2fs_alloc_block2(ext2_filsys fs, blk64_t goal,
 224                              char *block_buf, blk64_t *ret)
 225 {
 226         errcode_t       retval;
 227         blk64_t         block;
 228         char            *buf = 0;
 229
 230         if (!block_buf) {
 231                 retval = ext2fs_get_mem(fs->blocksize, &buf);
 232                 if (retval)
 233                         return retval;
 234                 block_buf = buf;
 235         }
 236         memset(block_buf, 0, fs->blocksize);
 237
 238         if (fs->get_alloc_block) {
 239                 retval = (fs->get_alloc_block)(fs, goal, &block);
 240                 if (retval)
 241                         goto fail;
 242         } else {
 243                 if (!fs->block_map) {
 244                         retval = ext2fs_read_block_bitmap(fs);
 245                         if (retval)
 246                                 goto fail;
 247                 }
 248
 249                 retval = ext2fs_new_block2(fs, goal, 0, &block);
 250                 if (retval)
 251                         goto fail;
 252         }
 253
 254         retval = io_channel_write_blk64(fs->io, block, 1, block_buf);
 255         if (retval)
 256                 goto fail;
 257
 258         ext2fs_block_alloc_stats2(fs, block, +1);
 259         *ret = block;
 260
 261 fail:
 262         if (buf)
 263                 ext2fs_free_mem(&buf);
 264         return retval;
 265 }
 266
 267 errcode_t ext2fs_alloc_block(ext2_filsys fs, blk_t goal,
 268                              char *block_buf, blk_t *ret)
 269 {
 270         errcode_t retval;
 271         blk64_t val;
 272         retval = ext2fs_alloc_block2(fs, goal, block_buf, &val);
 273         if (!retval)
 274                 *ret = (blk_t) val;
 275         return retval;
 276 }
 277
 278 errcode_t ext2fs_get_free_blocks2(ext2_filsys fs, blk64_t start, blk64_t finish,
 279                                  int num, ext2fs_block_bitmap map, blk64_t *ret)
 280 {
 281         blk64_t b = start;
 282         int     c_ratio;
 283
 284         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 285
 286         if (!map)
 287                 map = fs->block_map;
 288         if (!map)
 289                 return EXT2_ET_NO_BLOCK_BITMAP;
 290         if (!b)
 291                 b = fs->super->s_first_data_block;
 292         if (!finish)
 293                 finish = start;
 294         if (!num)
 295                 num = 1;
 296         c_ratio = 1 << ext2fs_get_bitmap_granularity(map);
 297         b &= ~(c_ratio - 1);
 298         finish &= ~(c_ratio -1);
 299         do {
 300                 if (b+num-1 > ext2fs_blocks_count(fs->super))
 301                         b = fs->super->s_first_data_block;
 302                 if (ext2fs_fast_test_block_bitmap_range2(map, b, num)) {
 303                         *ret = b;
 304                         return 0;
 305                 }
 306                 b += c_ratio;
 307         } while (b != finish);
 308         return EXT2_ET_BLOCK_ALLOC_FAIL;
 309 }
 310
 311 errcode_t ext2fs_get_free_blocks(ext2_filsys fs, blk_t start, blk_t finish,
 312                                  int num, ext2fs_block_bitmap map, blk_t *ret)
 313 {
 314         errcode_t retval;
 315         blk64_t val;
 316         retval = ext2fs_get_free_blocks2(fs, start, finish, num, map, &val);
 317         if(!retval)
 318                 *ret = (blk_t) val;
 319         return retval;
 320 }
 321
 322 void ext2fs_set_alloc_block_callback(ext2_filsys fs,
 323                                      errcode_t (*func)(ext2_filsys fs,
 324                                                        blk64_t goal,
 325                                                        blk64_t *ret),
 326                                      errcode_t (**old)(ext2_filsys fs,
 327                                                        blk64_t goal,
 328                                                        blk64_t *ret))
 329 {
 330         if (!fs || fs->magic != EXT2_ET_MAGIC_EXT2FS_FILSYS)
 331                 return;
 332
 333         if (old)
 334                 *old = fs->get_alloc_block;
 335
 336         fs->get_alloc_block = func;
 337 }