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 (!(EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
  35                                          EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) ||
  36             !(ext2fs_bg_flags_test(fs, group, EXT2_BG_BLOCK_UNINIT)))
  37                 return;
  38
  39         /* uninit block bitmaps are now initialized in read_bitmaps() */
  40
  41         ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
  42         ext2fs_group_desc_csum_set(fs, group);
  43         ext2fs_mark_super_dirty(fs);
  44         ext2fs_mark_bb_dirty(fs);
  45 }
  46
  47 /*
  48  * Check for uninit inode bitmaps and deal with them appropriately
  49  */
  50 static void check_inode_uninit(ext2_filsys fs, ext2fs_inode_bitmap map,
  51                           dgrp_t group)
  52 {
  53         ext2_ino_t      i, ino;
  54
  55         if (!(EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
  56                                          EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) ||
  57             !(ext2fs_bg_flags_test(fs, group, EXT2_BG_INODE_UNINIT)))
  58                 return;
  59
  60         ino = (group * fs->super->s_inodes_per_group) + 1;
  61         for (i=0; i < fs->super->s_inodes_per_group; i++, ino++)
  62                 ext2fs_fast_unmark_inode_bitmap2(map, ino);
  63
  64         ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT);
  65         /* Mimics what the kernel does */
  66         ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
  67         ext2fs_group_desc_csum_set(fs, group);
  68         ext2fs_mark_ib_dirty(fs);
  69         ext2fs_mark_super_dirty(fs);
  70 }
  71
  72 /*
  73  * Right now, just search forward from the parent directory's block
  74  * group to find the next free inode.
  75  *
  76  * Should have a special policy for directories.
  77  */
  78 errcode_t ext2fs_new_inode(ext2_filsys fs, ext2_ino_t dir,
  79                            int mode EXT2FS_ATTR((unused)),
  80                            ext2fs_inode_bitmap map, ext2_ino_t *ret)
  81 {
  82         ext2_ino_t      start_inode = 0;
  83         ext2_ino_t      i, ino_in_group, upto, first_zero;
  84         errcode_t       retval;
  85         dgrp_t          group;
  86
  87         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
  88
  89         if (!map)
  90                 map = fs->inode_map;
  91         if (!map)
  92                 return EXT2_ET_NO_INODE_BITMAP;
  93
  94         if (dir > 0) {
  95                 group = (dir - 1) / EXT2_INODES_PER_GROUP(fs->super);
  96                 start_inode = (group * EXT2_INODES_PER_GROUP(fs->super)) + 1;
  97         }
  98         if (start_inode < EXT2_FIRST_INODE(fs->super))
  99                 start_inode = EXT2_FIRST_INODE(fs->super);
 100         if (start_inode > fs->super->s_inodes_count)
 101                 return EXT2_ET_INODE_ALLOC_FAIL;
 102         i = start_inode;
 103         do {
 104                 ino_in_group = (i - 1) % EXT2_INODES_PER_GROUP(fs->super);
 105                 group = (i - 1) / EXT2_INODES_PER_GROUP(fs->super);
 106
 107                 check_inode_uninit(fs, map, group);
 108                 upto = i + (EXT2_INODES_PER_GROUP(fs->super) - ino_in_group);
 109                 if (i < start_inode && upto >= start_inode)
 110                         upto = start_inode - 1;
 111                 if (upto > fs->super->s_inodes_count)
 112                         upto = fs->super->s_inodes_count;
 113
 114                 retval = ext2fs_find_first_zero_inode_bitmap2(map, i, upto,
 115                                                               &first_zero);
 116                 if (retval == 0) {
 117                         i = first_zero;
 118                         break;
 119                 }
 120                 if (retval != ENOENT)
 121                         return EXT2_ET_INODE_ALLOC_FAIL;
 122                 i = upto + 1;
 123                 if (i > fs->super->s_inodes_count)
 124                         i = EXT2_FIRST_INODE(fs->super);
 125         } while (i != start_inode);
 126
 127         if (ext2fs_test_inode_bitmap2(map, i))
 128                 return EXT2_ET_INODE_ALLOC_FAIL;
 129         *ret = i;
 130         return 0;
 131 }
 132
 133 /*
 134  * Stupid algorithm --- we now just search forward starting from the
 135  * goal.  Should put in a smarter one someday....
 136  */
 137 errcode_t ext2fs_new_block2(ext2_filsys fs, blk64_t goal,
 138                            ext2fs_block_bitmap map, blk64_t *ret)
 139 {
 140         errcode_t retval;
 141         blk64_t b = 0;
 142
 143         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 144
 145         if (!map)
 146                 map = fs->block_map;
 147         if (!map)
 148                 return EXT2_ET_NO_BLOCK_BITMAP;
 149         if (!goal || (goal >= ext2fs_blocks_count(fs->super)))
 150                 goal = fs->super->s_first_data_block;
 151         goal &= ~EXT2FS_CLUSTER_MASK(fs);
 152
 153         retval = ext2fs_find_first_zero_block_bitmap2(map,
 154                         goal, ext2fs_blocks_count(fs->super) - 1, &b);
 155         if ((retval == ENOENT) && (goal != fs->super->s_first_data_block))
 156                 retval = ext2fs_find_first_zero_block_bitmap2(map,
 157                         fs->super->s_first_data_block, goal - 1, &b);
 158         if (retval == ENOENT)
 159                 return EXT2_ET_BLOCK_ALLOC_FAIL;
 160         if (retval)
 161                 return retval;
 162
 163         clear_block_uninit(fs, ext2fs_group_of_blk2(fs, b));
 164         *ret = b;
 165         return 0;
 166 }
 167
 168 errcode_t ext2fs_new_block(ext2_filsys fs, blk_t goal,
 169                            ext2fs_block_bitmap map, blk_t *ret)
 170 {
 171         errcode_t retval;
 172         blk64_t val;
 173         retval = ext2fs_new_block2(fs, goal, map, &val);
 174         if (!retval)
 175                 *ret = (blk_t) val;
 176         return retval;
 177 }
 178
 179 /*
 180  * This function zeros out the allocated block, and updates all of the
 181  * appropriate filesystem records.
 182  */
 183 errcode_t ext2fs_alloc_block2(ext2_filsys fs, blk64_t goal,
 184                              char *block_buf, blk64_t *ret)
 185 {
 186         errcode_t       retval;
 187         blk64_t         block;
 188         char            *buf = 0;
 189
 190         if (!block_buf) {
 191                 retval = ext2fs_get_mem(fs->blocksize, &buf);
 192                 if (retval)
 193                         return retval;
 194                 block_buf = buf;
 195         }
 196         memset(block_buf, 0, fs->blocksize);
 197
 198         if (fs->get_alloc_block) {
 199                 retval = (fs->get_alloc_block)(fs, goal, &block);
 200                 if (retval)
 201                         goto fail;
 202         } else {
 203                 if (!fs->block_map) {
 204                         retval = ext2fs_read_block_bitmap(fs);
 205                         if (retval)
 206                                 goto fail;
 207                 }
 208
 209                 retval = ext2fs_new_block2(fs, goal, 0, &block);
 210                 if (retval)
 211                         goto fail;
 212         }
 213
 214         retval = io_channel_write_blk64(fs->io, block, 1, block_buf);
 215         if (retval)
 216                 goto fail;
 217
 218         ext2fs_block_alloc_stats2(fs, block, +1);
 219         *ret = block;
 220
 221 fail:
 222         if (buf)
 223                 ext2fs_free_mem(&buf);
 224         return retval;
 225 }
 226
 227 errcode_t ext2fs_alloc_block(ext2_filsys fs, blk_t goal,
 228                              char *block_buf, blk_t *ret)
 229 {
 230         errcode_t retval;
 231         blk64_t val;
 232         retval = ext2fs_alloc_block2(fs, goal, block_buf, &val);
 233         if (!retval)
 234                 *ret = (blk_t) val;
 235         return retval;
 236 }
 237
 238 errcode_t ext2fs_get_free_blocks2(ext2_filsys fs, blk64_t start, blk64_t finish,
 239                                  int num, ext2fs_block_bitmap map, blk64_t *ret)
 240 {
 241         blk64_t b = start;
 242         int     c_ratio;
 243
 244         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 245
 246         if (!map)
 247                 map = fs->block_map;
 248         if (!map)
 249                 return EXT2_ET_NO_BLOCK_BITMAP;
 250         if (!b)
 251                 b = fs->super->s_first_data_block;
 252         if (!finish)
 253                 finish = start;
 254         if (!num)
 255                 num = 1;
 256         c_ratio = 1 << ext2fs_get_bitmap_granularity(map);
 257         b &= ~(c_ratio - 1);
 258         finish &= ~(c_ratio -1);
 259         do {
 260                 if (b+num-1 > ext2fs_blocks_count(fs->super))
 261                         b = fs->super->s_first_data_block;
 262                 if (ext2fs_fast_test_block_bitmap_range2(map, b, num)) {
 263                         *ret = b;
 264                         return 0;
 265                 }
 266                 b += c_ratio;
 267         } while (b != finish);
 268         return EXT2_ET_BLOCK_ALLOC_FAIL;
 269 }
 270
 271 errcode_t ext2fs_get_free_blocks(ext2_filsys fs, blk_t start, blk_t finish,
 272                                  int num, ext2fs_block_bitmap map, blk_t *ret)
 273 {
 274         errcode_t retval;
 275         blk64_t val;
 276         retval = ext2fs_get_free_blocks2(fs, start, finish, num, map, &val);
 277         if(!retval)
 278                 *ret = (blk_t) val;
 279         return retval;
 280 }
 281
 282 void ext2fs_set_alloc_block_callback(ext2_filsys fs,
 283                                      errcode_t (*func)(ext2_filsys fs,
 284                                                        blk64_t goal,
 285                                                        blk64_t *ret),
 286                                      errcode_t (**old)(ext2_filsys fs,
 287                                                        blk64_t goal,
 288                                                        blk64_t *ret))
 289 {
 290         if (!fs || fs->magic != EXT2_ET_MAGIC_EXT2FS_FILSYS)
 291                 return;
 292
 293         if (old)
 294                 *old = fs->get_alloc_block;
 295
 296         fs->get_alloc_block = func;
 297 }