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