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  * Clear the uninit block bitmap flag if necessary
  31  */
  32 static void clear_block_uninit(ext2_filsys fs, dgrp_t group)
  33 {
  34         if (!ext2fs_has_group_desc_csum(fs) ||
  35             !(ext2fs_bg_flags_test(fs, group, EXT2_BG_BLOCK_UNINIT)))
  36                 return;
  37
  38         /* uninit block bitmaps are now initialized in read_bitmaps() */
  39
  40         ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
  41         ext2fs_group_desc_csum_set(fs, group);
  42         ext2fs_mark_super_dirty(fs);
  43         ext2fs_mark_bb_dirty(fs);
  44 }
  45
  46 /*
  47  * Check for uninit inode bitmaps and deal with them appropriately
  48  */
  49 static void check_inode_uninit(ext2_filsys fs, ext2fs_inode_bitmap map,
  50                           dgrp_t group)
  51 {
  52         ext2_ino_t      i, ino;
  53
  54         if (!ext2fs_has_group_desc_csum(fs) ||
  55             !(ext2fs_bg_flags_test(fs, group, EXT2_BG_INODE_UNINIT)))
  56                 return;
  57
  58         ino = (group * fs->super->s_inodes_per_group) + 1;
  59         for (i=0; i < fs->super->s_inodes_per_group; i++, ino++)
  60                 ext2fs_fast_unmark_inode_bitmap2(map, ino);
  61
  62         ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT);
  63         /* Mimics what the kernel does */
  64         ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
  65         ext2fs_group_desc_csum_set(fs, group);
  66         ext2fs_mark_ib_dirty(fs);
  67         ext2fs_mark_super_dirty(fs);
  68 }
  69
  70 /*
  71  * Right now, just search forward from the parent directory's block
  72  * group to find the next free inode.
  73  *
  74  * Should have a special policy for directories.
  75  */
  76 errcode_t ext2fs_new_inode(ext2_filsys fs, ext2_ino_t dir,
  77                            int mode EXT2FS_ATTR((unused)),
  78                            ext2fs_inode_bitmap map, ext2_ino_t *ret)
  79 {
  80         ext2_ino_t      start_inode = 0;
  81         ext2_ino_t      i, ino_in_group, upto, first_zero;
  82         errcode_t       retval;
  83         dgrp_t          group;
  84
  85         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
  86
  87         if (!map)
  88                 map = fs->inode_map;
  89         if (!map)
  90                 return EXT2_ET_NO_INODE_BITMAP;
  91
  92         if (dir > 0) {
  93                 group = (dir - 1) / EXT2_INODES_PER_GROUP(fs->super);
  94                 start_inode = (group * EXT2_INODES_PER_GROUP(fs->super)) + 1;
  95         }
  96         if (start_inode < EXT2_FIRST_INODE(fs->super))
  97                 start_inode = EXT2_FIRST_INODE(fs->super);
  98         if (start_inode > fs->super->s_inodes_count)
  99                 return EXT2_ET_INODE_ALLOC_FAIL;
 100         i = start_inode;
 101         do {
 102                 ino_in_group = (i - 1) % EXT2_INODES_PER_GROUP(fs->super);
 103                 group = (i - 1) / EXT2_INODES_PER_GROUP(fs->super);
 104
 105                 check_inode_uninit(fs, map, group);
 106                 upto = i + (EXT2_INODES_PER_GROUP(fs->super) - ino_in_group);
 107                 if (i < start_inode && upto >= start_inode)
 108                         upto = start_inode - 1;
 109                 if (upto > fs->super->s_inodes_count)
 110                         upto = fs->super->s_inodes_count;
 111
 112                 retval = ext2fs_find_first_zero_inode_bitmap2(map, i, upto,
 113                                                               &first_zero);
 114                 if (retval == 0) {
 115                         i = first_zero;
 116                         break;
 117                 }
 118                 if (retval != ENOENT)
 119                         return EXT2_ET_INODE_ALLOC_FAIL;
 120                 i = upto + 1;
 121                 if (i > fs->super->s_inodes_count)
 122                         i = EXT2_FIRST_INODE(fs->super);
 123         } while (i != start_inode);
 124
 125         if (ext2fs_test_inode_bitmap2(map, i))
 126                 return EXT2_ET_INODE_ALLOC_FAIL;
 127         *ret = i;
 128         return 0;
 129 }
 130
 131 /*
 132  * Stupid algorithm --- we now just search forward starting from the
 133  * goal.  Should put in a smarter one someday....
 134  */
 135 errcode_t ext2fs_new_block2(ext2_filsys fs, blk64_t goal,
 136                            ext2fs_block_bitmap map, blk64_t *ret)
 137 {
 138         errcode_t retval;
 139         blk64_t b = 0;
 140
 141         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 142
 143         if (!map)
 144                 map = fs->block_map;
 145         if (!map)
 146                 return EXT2_ET_NO_BLOCK_BITMAP;
 147         if (!goal || (goal >= ext2fs_blocks_count(fs->super)))
 148                 goal = fs->super->s_first_data_block;
 149         goal &= ~EXT2FS_CLUSTER_MASK(fs);
 150
 151         retval = ext2fs_find_first_zero_block_bitmap2(map,
 152                         goal, ext2fs_blocks_count(fs->super) - 1, &b);
 153         if ((retval == ENOENT) && (goal != fs->super->s_first_data_block))
 154                 retval = ext2fs_find_first_zero_block_bitmap2(map,
 155                         fs->super->s_first_data_block, goal - 1, &b);
 156         if (retval == ENOENT)
 157                 return EXT2_ET_BLOCK_ALLOC_FAIL;
 158         if (retval)
 159                 return retval;
 160
 161         clear_block_uninit(fs, ext2fs_group_of_blk2(fs, b));
 162         *ret = b;
 163         return 0;
 164 }
 165
 166 errcode_t ext2fs_new_block(ext2_filsys fs, blk_t goal,
 167                            ext2fs_block_bitmap map, blk_t *ret)
 168 {
 169         errcode_t retval;
 170         blk64_t val;
 171         retval = ext2fs_new_block2(fs, goal, map, &val);
 172         if (!retval)
 173                 *ret = (blk_t) val;
 174         return retval;
 175 }
 176
 177 /*
 178  * This function zeros out the allocated block, and updates all of the
 179  * appropriate filesystem records.
 180  */
 181 errcode_t ext2fs_alloc_block2(ext2_filsys fs, blk64_t goal,
 182                              char *block_buf, blk64_t *ret)
 183 {
 184         errcode_t       retval;
 185         blk64_t         block;
 186         char            *buf = 0;
 187
 188         if (!block_buf) {
 189                 retval = ext2fs_get_mem(fs->blocksize, &buf);
 190                 if (retval)
 191                         return retval;
 192                 block_buf = buf;
 193         }
 194         memset(block_buf, 0, fs->blocksize);
 195
 196         if (fs->get_alloc_block) {
 197                 retval = (fs->get_alloc_block)(fs, goal, &block);
 198                 if (retval)
 199                         goto fail;
 200         } else {
 201                 if (!fs->block_map) {
 202                         retval = ext2fs_read_block_bitmap(fs);
 203                         if (retval)
 204                                 goto fail;
 205                 }
 206
 207                 retval = ext2fs_new_block2(fs, goal, 0, &block);
 208                 if (retval)
 209                         goto fail;
 210         }
 211
 212         retval = io_channel_write_blk64(fs->io, block, 1, block_buf);
 213         if (retval)
 214                 goto fail;
 215
 216         ext2fs_block_alloc_stats2(fs, block, +1);
 217         *ret = block;
 218
 219 fail:
 220         if (buf)
 221                 ext2fs_free_mem(&buf);
 222         return retval;
 223 }
 224
 225 errcode_t ext2fs_alloc_block(ext2_filsys fs, blk_t goal,
 226                              char *block_buf, blk_t *ret)
 227 {
 228         errcode_t retval;
 229         blk64_t val;
 230         retval = ext2fs_alloc_block2(fs, goal, block_buf, &val);
 231         if (!retval)
 232                 *ret = (blk_t) val;
 233         return retval;
 234 }
 235
 236 errcode_t ext2fs_get_free_blocks2(ext2_filsys fs, blk64_t start, blk64_t finish,
 237                                  int num, ext2fs_block_bitmap map, blk64_t *ret)
 238 {
 239         blk64_t b = start;
 240         int     c_ratio;
 241
 242         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 243
 244         if (!map)
 245                 map = fs->block_map;
 246         if (!map)
 247                 return EXT2_ET_NO_BLOCK_BITMAP;
 248         if (!b)
 249                 b = fs->super->s_first_data_block;
 250         if (!finish)
 251                 finish = start;
 252         if (!num)
 253                 num = 1;
 254         c_ratio = 1 << ext2fs_get_bitmap_granularity(map);
 255         b &= ~(c_ratio - 1);
 256         finish &= ~(c_ratio -1);
 257         do {
 258                 if (b + num - 1 >= ext2fs_blocks_count(fs->super)) {
 259                         if (finish > start)
 260                                 return EXT2_ET_BLOCK_ALLOC_FAIL;
 261                         b = fs->super->s_first_data_block;
 262                 }
 263                 if (ext2fs_fast_test_block_bitmap_range2(map, b, num)) {
 264                         *ret = b;
 265                         return 0;
 266                 }
 267                 b += c_ratio;
 268         } while (b != finish);
 269         return EXT2_ET_BLOCK_ALLOC_FAIL;
 270 }
 271
 272 errcode_t ext2fs_get_free_blocks(ext2_filsys fs, blk_t start, blk_t finish,
 273                                  int num, ext2fs_block_bitmap map, blk_t *ret)
 274 {
 275         errcode_t retval;
 276         blk64_t val;
 277         retval = ext2fs_get_free_blocks2(fs, start, finish, num, map, &val);
 278         if(!retval)
 279                 *ret = (blk_t) val;
 280         return retval;
 281 }
 282
 283 void ext2fs_set_alloc_block_callback(ext2_filsys fs,
 284                                      errcode_t (*func)(ext2_filsys fs,
 285                                                        blk64_t goal,
 286                                                        blk64_t *ret),
 287                                      errcode_t (**old)(ext2_filsys fs,
 288                                                        blk64_t goal,
 289                                                        blk64_t *ret))
 290 {
 291         if (!fs || fs->magic != EXT2_ET_MAGIC_EXT2FS_FILSYS)
 292                 return;
 293
 294         if (old)
 295                 *old = fs->get_alloc_block;
 296
 297         fs->get_alloc_block = func;
 298 }