fs/ext4/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 "ext2_fs.h"
  13 #include "ext2fs.h"
  14
  15 /*
  16  * Check for uninit block bitmaps and deal with them appropriately
  17  */
  18 static void check_block_uninit(ext2_filsys fs, ext2fs_block_bitmap map,
  19                           dgrp_t group)
  20 {
  21         blk_t           i;
  22         blk_t           blk, super_blk, old_desc_blk, new_desc_blk;
  23         int             old_desc_blocks;
  24
  25         if (!(EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
  26                                          EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) ||
  27             !(fs->group_desc[group].bg_flags & EXT2_BG_BLOCK_UNINIT))
  28                 return;
  29
  30         blk = (group * fs->super->s_blocks_per_group) +
  31                 fs->super->s_first_data_block;
  32
  33         ext2fs_super_and_bgd_loc(fs, group, &super_blk,
  34                                  &old_desc_blk, &new_desc_blk, 0);
  35
  36         if (fs->super->s_feature_incompat &
  37             EXT2_FEATURE_INCOMPAT_META_BG)
  38                 old_desc_blocks = fs->super->s_first_meta_bg;
  39         else
  40                 old_desc_blocks = fs->desc_blocks + fs->super->s_reserved_gdt_blocks;
  41
  42         for (i=0; i < fs->super->s_blocks_per_group; i++, blk++) {
  43                 if ((blk == super_blk) ||
  44                     (old_desc_blk && old_desc_blocks &&
  45                      (blk >= old_desc_blk) &&
  46                      (blk < old_desc_blk + old_desc_blocks)) ||
  47                     (new_desc_blk && (blk == new_desc_blk)) ||
  48                     (blk == fs->group_desc[group].bg_block_bitmap) ||
  49                     (blk == fs->group_desc[group].bg_inode_bitmap) ||
  50                     (blk >= fs->group_desc[group].bg_inode_table &&
  51                      (blk < fs->group_desc[group].bg_inode_table
  52                       + fs->inode_blocks_per_group)))
  53                         ext2fs_fast_mark_block_bitmap(map, blk);
  54                 else
  55                         ext2fs_fast_unmark_block_bitmap(map, blk);
  56         }
  57         fs->group_desc[group].bg_flags &= ~EXT2_BG_BLOCK_UNINIT;
  58         ext2fs_group_desc_csum_set(fs, group);
  59 }
  60
  61 /*
  62  * Check for uninit inode bitmaps and deal with them appropriately
  63  */
  64 static void check_inode_uninit(ext2_filsys fs, ext2fs_inode_bitmap map,
  65                           dgrp_t group)
  66 {
  67         ext2_ino_t      i, ino;
  68
  69         if (!(EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
  70                                          EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) ||
  71             !(fs->group_desc[group].bg_flags & EXT2_BG_INODE_UNINIT))
  72                 return;
  73
  74         ino = (group * fs->super->s_inodes_per_group) + 1;
  75         for (i=0; i < fs->super->s_inodes_per_group; i++, ino++)
  76                 ext2fs_fast_unmark_inode_bitmap(map, ino);
  77
  78         fs->group_desc[group].bg_flags &= ~EXT2_BG_INODE_UNINIT;
  79         check_block_uninit(fs, fs->block_map, group);
  80 }
  81
  82 /*
  83  * Right now, just search forward from the parent directory's block
  84  * group to find the next free inode.
  85  *
  86  * Should have a special policy for directories.
  87  */
  88 errcode_t ext2fs_new_inode(ext2_filsys fs, ext2_ino_t dir,
  89                            int mode EXT2FS_ATTR((unused)),
  90                            ext2fs_inode_bitmap map, ext2_ino_t *ret)
  91 {
  92         ext2_ino_t      dir_group = 0;
  93         ext2_ino_t      i;
  94         ext2_ino_t      start_inode;
  95
  96         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
  97
  98         if (!map)
  99                 map = fs->inode_map;
 100         if (!map)
 101                 return EXT2_ET_NO_INODE_BITMAP;
 102
 103         if (dir > 0)
 104                 dir_group = (dir - 1) / EXT2_INODES_PER_GROUP(fs->super);
 105
 106         start_inode = (dir_group * EXT2_INODES_PER_GROUP(fs->super)) + 1;
 107         if (start_inode < EXT2_FIRST_INODE(fs->super))
 108                 start_inode = EXT2_FIRST_INODE(fs->super);
 109         if (start_inode > fs->super->s_inodes_count)
 110                 return EXT2_ET_INODE_ALLOC_FAIL;
 111         i = start_inode;
 112
 113         do {
 114                 if (((i - 1) % EXT2_INODES_PER_GROUP(fs->super)) == 0)
 115                         check_inode_uninit(fs, map, (i - 1) /
 116                                            EXT2_INODES_PER_GROUP(fs->super));
 117
 118                 if (!ext2fs_fast_test_inode_bitmap(map, i))
 119                         break;
 120                 i++;
 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_bitmap(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_block(ext2_filsys fs, blk_t goal,
 136                            ext2fs_block_bitmap map, blk_t *ret)
 137 {
 138         blk_t   i;
 139
 140         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 141
 142         if (!map)
 143                 map = fs->block_map;
 144         if (!map)
 145                 return EXT2_ET_NO_BLOCK_BITMAP;
 146         if (!goal || (goal >= fs->super->s_blocks_count))
 147                 goal = fs->super->s_first_data_block;
 148         i = goal;
 149         check_block_uninit(fs, map,
 150                            (i - fs->super->s_first_data_block) /
 151                            EXT2_BLOCKS_PER_GROUP(fs->super));
 152         do {
 153                 if (((i - fs->super->s_first_data_block) %
 154                      EXT2_BLOCKS_PER_GROUP(fs->super)) == 0)
 155                         check_block_uninit(fs, map,
 156                                            (i - fs->super->s_first_data_block) /
 157                                            EXT2_BLOCKS_PER_GROUP(fs->super));
 158
 159                 if (!ext2fs_fast_test_block_bitmap(map, i)) {
 160                         *ret = i;
 161                         return 0;
 162                 }
 163                 i++;
 164                 if (i >= fs->super->s_blocks_count)
 165                         i = fs->super->s_first_data_block;
 166         } while (i != goal);
 167         return EXT2_ET_BLOCK_ALLOC_FAIL;
 168 }
 169
 170 /*
 171  * This function zeros out the allocated block, and updates all of the
 172  * appropriate filesystem records.
 173  */
 174 errcode_t ext2fs_alloc_block(ext2_filsys fs, blk_t goal,
 175                              char *block_buf, blk_t *ret)
 176 {
 177         errcode_t       retval;
 178         blk_t           block;
 179         char            *buf = 0;
 180
 181         if (!block_buf) {
 182                 retval = ext2fs_get_mem(fs->blocksize, &buf);
 183                 if (retval)
 184                         return retval;
 185                 block_buf = buf;
 186         }
 187         memset(block_buf, 0, fs->blocksize);
 188
 189         if (fs->get_alloc_block) {
 190                 blk64_t new;
 191
 192                 retval = (fs->get_alloc_block)(fs, (blk64_t) goal, &new);
 193                 if (retval)
 194                         goto fail;
 195                 block = (blk_t) new;
 196         } else {
 197                 if (!fs->block_map) {
 198                         retval = ext2fs_read_block_bitmap(fs);
 199                         if (retval)
 200                                 goto fail;
 201                 }
 202
 203                 retval = ext2fs_new_block(fs, goal, 0, &block);
 204                 if (retval)
 205                         goto fail;
 206         }
 207
 208 #if 0
 209 //uma
 210         retval = io_channel_write_blk(fs->io, block, 1, block_buf);
 211 #endif
 212                 put_ext4(dev_desc, (uint64_t)(block * fs->blocksize),block_buf,(uint32_t)(fs->blocksize));
 213                 retval=0;
 214
 215         if (retval)
 216                 goto fail;
 217
 218         ext2fs_block_alloc_stats(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_get_free_blocks(ext2_filsys fs, blk_t start, blk_t finish,
 228                                  int num, ext2fs_block_bitmap map, blk_t *ret)
 229 {
 230         blk_t   b = start;
 231
 232         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 233
 234         if (!map)
 235                 map = fs->block_map;
 236         if (!map)
 237                 return EXT2_ET_NO_BLOCK_BITMAP;
 238         if (!b)
 239                 b = fs->super->s_first_data_block;
 240         if (!finish)
 241                 finish = start;
 242         if (!num)
 243                 num = 1;
 244         do {
 245                 if (b+num-1 > fs->super->s_blocks_count)
 246                         b = fs->super->s_first_data_block;
 247                 if (ext2fs_fast_test_block_bitmap_range(map, b, num)) {
 248                         *ret = b;
 249                         return 0;
 250                 }
 251                 b++;
 252         } while (b != finish);
 253         return EXT2_ET_BLOCK_ALLOC_FAIL;
 254 }
 255
 256 void ext2fs_set_alloc_block_callback(ext2_filsys fs,
 257                                      errcode_t (*func)(ext2_filsys fs,
 258                                                        blk64_t goal,
 259                                                        blk64_t *ret),
 260                                      errcode_t (**old)(ext2_filsys fs,
 261                                                        blk64_t goal,
 262                                                        blk64_t *ret))
 263 {
 264         if (!fs || fs->magic != EXT2_ET_MAGIC_EXT2FS_FILSYS)
 265                 return;
 266
 267         if (old)
 268                 *old = fs->get_alloc_block;
 269
 270         fs->get_alloc_block = func;
 271 }