lwext4/ext4_ialloc.c

   1 /*
   2  * Copyright (c) 2013 Grzegorz Kostka (kostka.grzegorz@gmail.com)
   3  *
   4  *
   5  * HelenOS:
   6  * Copyright (c) 2012 Martin Sucha
   7  * Copyright (c) 2012 Frantisek Princ
   8  * All rights reserved.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  *
  14  * - Redistributions of source code must retain the above copyright
  15  *   notice, this list of conditions and the following disclaimer.
  16  * - Redistributions in binary form must reproduce the above copyright
  17  *   notice, this list of conditions and the following disclaimer in the
  18  *   documentation and/or other materials provided with the distribution.
  19  * - The name of the author may not be used to endorse or promote products
  20  *   derived from this software without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  23  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  24  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  25  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  27  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  28  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  29  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  31  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32  */
  33
  34 /** @addtogroup lwext4
  35  * @{
  36  */
  37 /**
  38  * @file  ext4_ialloc.c
  39  * @brief Inode allocation procedures.
  40  */
  41
  42 #include "ext4_config.h"
  43 #include "ext4_types.h"
  44 #include "ext4_ialloc.h"
  45 #include "ext4_super.h"
  46 #include "ext4_crc32c.h"
  47 #include "ext4_fs.h"
  48 #include "ext4_blockdev.h"
  49 #include "ext4_block_group.h"
  50 #include "ext4_bitmap.h"
  51
  52 /**@brief  Convert i-node number to relative index in block group.
  53  * @param sb    Superblock
  54  * @param inode I-node number to be converted
  55  * @return Index of the i-node in the block group
  56  */
  57 static uint32_t ext4_ialloc_inode2index_in_group(struct ext4_sblock *sb,
  58                                                  uint32_t inode)
  59 {
  60         uint32_t inodes_per_group = ext4_get32(sb, inodes_per_group);
  61         return (inode - 1) % inodes_per_group;
  62 }
  63
  64 /**@brief Convert relative index of i-node to absolute i-node number.
  65  * @param sb    Superblock
  66  * @param index Index to be converted
  67  * @return Absolute number of the i-node
  68  *
  69  */
  70 static uint32_t ext4_ialloc_index_in_group2inode(struct ext4_sblock *sb,
  71                                                  uint32_t index, uint32_t bgid)
  72 {
  73         uint32_t inodes_per_group = ext4_get32(sb, inodes_per_group);
  74         return bgid * inodes_per_group + (index + 1);
  75 }
  76
  77 /**@brief Compute block group number from the i-node number.
  78  * @param sb    Superblock
  79  * @param inode I-node number to be found the block group for
  80  * @return Block group number computed from i-node number
  81  */
  82 static uint32_t ext4_ialloc_get_bgid_of_inode(struct ext4_sblock *sb,
  83                                               uint32_t inode)
  84 {
  85         uint32_t inodes_per_group = ext4_get32(sb, inodes_per_group);
  86         return (inode - 1) / inodes_per_group;
  87 }
  88
  89 #if CONFIG_META_CSUM_ENABLE
  90 static uint32_t ext4_ialloc_bitmap_csum(struct ext4_sblock *sb,
  91                                         void *bitmap)
  92 {
  93         uint32_t checksum = 0;
  94         if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
  95                 uint32_t inodes_per_group =
  96                         ext4_get32(sb, inodes_per_group);
  97
  98                 /* First calculate crc32 checksum against fs uuid */
  99                 checksum = ext4_crc32c(EXT4_CRC32_INIT, sb->uuid,
 100                                 sizeof(sb->uuid));
 101                 /* Then calculate crc32 checksum against inode bitmap */
 102                 checksum = ext4_crc32c(checksum, bitmap,
 103                                      (inodes_per_group + 7) / 8);
 104         }
 105         return checksum;
 106 }
 107 #else
 108 #define ext4_ialloc_bitmap_csum(...) 0
 109 #endif
 110
 111 void ext4_ialloc_set_bitmap_csum(struct ext4_sblock *sb,
 112                                  struct ext4_bgroup *bg,
 113                                  void *bitmap __unused)
 114 {
 115         int desc_size = ext4_sb_get_desc_size(sb);
 116         uint32_t checksum = ext4_ialloc_bitmap_csum(sb, bitmap);
 117         uint16_t lo_checksum = to_le16(checksum & 0xFFFF),
 118                  hi_checksum = to_le16(checksum >> 16);
 119
 120         if (!ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM))
 121                 return;
 122
 123         /* See if we need to assign a 32bit checksum */
 124         bg->inode_bitmap_csum_lo = lo_checksum;
 125         if (desc_size == EXT4_MAX_BLOCK_GROUP_DESCRIPTOR_SIZE)
 126                 bg->inode_bitmap_csum_hi = hi_checksum;
 127
 128 }
 129
 130 #if CONFIG_META_CSUM_ENABLE
 131 static bool
 132 ext4_ialloc_verify_bitmap_csum(struct ext4_sblock *sb,
 133                                struct ext4_bgroup *bg,
 134                                void *bitmap __unused)
 135 {
 136
 137         int desc_size = ext4_sb_get_desc_size(sb);
 138         uint32_t checksum = ext4_ialloc_bitmap_csum(sb, bitmap);
 139         uint16_t lo_checksum = to_le16(checksum & 0xFFFF),
 140                  hi_checksum = to_le16(checksum >> 16);
 141
 142         if (!ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM))
 143                 return true;
 144
 145         if (bg->inode_bitmap_csum_lo != lo_checksum)
 146                 return false;
 147
 148         if (desc_size == EXT4_MAX_BLOCK_GROUP_DESCRIPTOR_SIZE)
 149                 if (bg->inode_bitmap_csum_hi != hi_checksum)
 150                         return false;
 151
 152         return true;
 153 }
 154 #else
 155 #define ext4_ialloc_verify_bitmap_csum(...) true
 156 #endif
 157
 158 int ext4_ialloc_free_inode(struct ext4_fs *fs, uint32_t index, bool is_dir)
 159 {
 160         struct ext4_sblock *sb = &fs->sb;
 161
 162         /* Compute index of block group and load it */
 163         uint32_t block_group = ext4_ialloc_get_bgid_of_inode(sb, index);
 164
 165         struct ext4_block_group_ref bg_ref;
 166         int rc = ext4_fs_get_block_group_ref(fs, block_group, &bg_ref);
 167         if (rc != EOK)
 168                 return rc;
 169
 170         /* Load i-node bitmap */
 171         uint32_t bitmap_block_addr =
 172             ext4_bg_get_inode_bitmap(bg_ref.block_group, sb);
 173
 174         struct ext4_block bitmap_block;
 175         rc = ext4_block_get(fs->bdev, &bitmap_block, bitmap_block_addr);
 176         if (rc != EOK)
 177                 return rc;
 178
 179         if (!ext4_ialloc_verify_bitmap_csum(sb,
 180                                bg_ref.block_group,
 181                                bitmap_block.data)) {
 182                 ext4_dbg(DEBUG_IALLOC,
 183                         DBG_WARN "Bitmap checksum failed."
 184                         "Group: %" PRIu32"\n",
 185                         bg_ref.index);
 186         }
 187
 188         /* Free i-node in the bitmap */
 189         uint32_t index_in_group = ext4_ialloc_inode2index_in_group(sb, index);
 190         ext4_bmap_bit_clr(bitmap_block.data, index_in_group);
 191         ext4_ialloc_set_bitmap_csum(sb, bg_ref.block_group,
 192                                     bitmap_block.data);
 193         bitmap_block.dirty = true;
 194
 195         /* Put back the block with bitmap */
 196         rc = ext4_block_set(fs->bdev, &bitmap_block);
 197         if (rc != EOK) {
 198                 /* Error in saving bitmap */
 199                 ext4_fs_put_block_group_ref(&bg_ref);
 200                 return rc;
 201         }
 202
 203         /* If released i-node is a directory, decrement used directories count
 204          */
 205         if (is_dir) {
 206                 uint32_t bg_used_dirs =
 207                     ext4_bg_get_used_dirs_count(bg_ref.block_group, sb);
 208                 bg_used_dirs--;
 209                 ext4_bg_set_used_dirs_count(bg_ref.block_group, sb,
 210                                             bg_used_dirs);
 211         }
 212
 213         /* Update block group free inodes count */
 214         uint32_t free_inodes =
 215             ext4_bg_get_free_inodes_count(bg_ref.block_group, sb);
 216         free_inodes++;
 217         ext4_bg_set_free_inodes_count(bg_ref.block_group, sb, free_inodes);
 218
 219         bg_ref.dirty = true;
 220
 221         /* Put back the modified block group */
 222         rc = ext4_fs_put_block_group_ref(&bg_ref);
 223         if (rc != EOK)
 224                 return rc;
 225
 226         /* Update superblock free inodes count */
 227         ext4_set32(sb, free_inodes_count,
 228                    ext4_get32(sb, free_inodes_count) + 1);
 229
 230         return EOK;
 231 }
 232
 233 int ext4_ialloc_alloc_inode(struct ext4_fs *fs, uint32_t *index, bool is_dir)
 234 {
 235         struct ext4_sblock *sb = &fs->sb;
 236
 237         uint32_t bgid = fs->last_inode_bg_id;
 238         uint32_t bg_count = ext4_block_group_cnt(sb);
 239         uint32_t sb_free_inodes = ext4_get32(sb, free_inodes_count);
 240         bool rewind = false;
 241
 242         /* Try to find free i-node in all block groups */
 243         while (bgid <= bg_count) {
 244
 245                 if (bgid == bg_count) {
 246                         if (rewind)
 247                                 break;
 248                         bg_count = fs->last_inode_bg_id;
 249                         bgid = 0;
 250                         rewind = true;
 251                         continue;
 252                 }
 253
 254                 /* Load block group to check */
 255                 struct ext4_block_group_ref bg_ref;
 256                 int rc = ext4_fs_get_block_group_ref(fs, bgid, &bg_ref);
 257                 if (rc != EOK)
 258                         return rc;
 259
 260                 struct ext4_bgroup *bg = bg_ref.block_group;
 261
 262                 /* Read necessary values for algorithm */
 263                 uint32_t free_inodes = ext4_bg_get_free_inodes_count(bg, sb);
 264                 uint32_t used_dirs = ext4_bg_get_used_dirs_count(bg, sb);
 265
 266                 /* Check if this block group is good candidate for allocation */
 267                 if (free_inodes > 0) {
 268                         /* Load block with bitmap */
 269                         uint32_t bitmap_block_addr =
 270                             ext4_bg_get_inode_bitmap(bg_ref.block_group, sb);
 271
 272                         struct ext4_block bitmap_block;
 273                         rc = ext4_block_get(fs->bdev, &bitmap_block,
 274                                             bitmap_block_addr);
 275                         if (rc != EOK) {
 276                                 ext4_fs_put_block_group_ref(&bg_ref);
 277                                 return rc;
 278                         }
 279
 280                         if (!ext4_ialloc_verify_bitmap_csum(sb,
 281                                                bg_ref.block_group,
 282                                                bitmap_block.data)) {
 283                                 ext4_dbg(DEBUG_IALLOC,
 284                                         DBG_WARN "Bitmap checksum failed."
 285                                         "Group: %" PRIu32"\n",
 286                                         bg_ref.index);
 287                         }
 288
 289                         /* Try to allocate i-node in the bitmap */
 290                         uint32_t inodes_in_group =
 291                             ext4_inodes_in_group_cnt(sb, bgid);
 292                         uint32_t index_in_group;
 293
 294                         rc = ext4_bmap_bit_find_clr(bitmap_block.data, 0,
 295                                                     inodes_in_group,
 296                                                     &index_in_group);
 297                         /* Block group has not any free i-node */
 298                         if (rc == ENOSPC) {
 299                                 rc = ext4_block_set(fs->bdev, &bitmap_block);
 300                                 if (rc != EOK) {
 301                                         ext4_fs_put_block_group_ref(&bg_ref);
 302                                         return rc;
 303                                 }
 304
 305                                 rc = ext4_fs_put_block_group_ref(&bg_ref);
 306                                 if (rc != EOK)
 307                                         return rc;
 308
 309                                 continue;
 310                         }
 311
 312                         ext4_bmap_bit_set(bitmap_block.data, index_in_group);
 313
 314                         /* Free i-node found, save the bitmap */
 315                         ext4_ialloc_set_bitmap_csum(sb, bg_ref.block_group,
 316                                                     bitmap_block.data);
 317                         bitmap_block.dirty = true;
 318
 319                         ext4_block_set(fs->bdev, &bitmap_block);
 320                         if (rc != EOK) {
 321                                 ext4_fs_put_block_group_ref(&bg_ref);
 322                                 return rc;
 323                         }
 324
 325                         /* Modify filesystem counters */
 326                         free_inodes--;
 327                         ext4_bg_set_free_inodes_count(bg, sb, free_inodes);
 328
 329                         /* Increment used directories counter */
 330                         if (is_dir) {
 331                                 used_dirs++;
 332                                 ext4_bg_set_used_dirs_count(bg, sb, used_dirs);
 333                         }
 334
 335                         /* Decrease unused inodes count */
 336                         uint32_t unused =
 337                             ext4_bg_get_itable_unused(bg, sb);
 338
 339                         uint32_t free = inodes_in_group - unused;
 340
 341                         if (index_in_group >= free) {
 342                                 unused = inodes_in_group -
 343                                          (index_in_group + 1);
 344                                 ext4_bg_set_itable_unused(bg, sb,
 345                                                           unused);
 346                         }
 347
 348                         /* Save modified block group */
 349                         bg_ref.dirty = true;
 350
 351                         rc = ext4_fs_put_block_group_ref(&bg_ref);
 352                         if (rc != EOK)
 353                                 return rc;
 354
 355                         /* Update superblock */
 356                         sb_free_inodes--;
 357                         ext4_set32(sb, free_inodes_count, sb_free_inodes);
 358
 359                         /* Compute the absolute i-nodex number */
 360                         *index = ext4_ialloc_index_in_group2inode(
 361                             sb, index_in_group, bgid);
 362
 363                         fs->last_inode_bg_id = bgid;
 364
 365                         return EOK;
 366                 }
 367
 368                 /* Block group not modified, put it and jump to the next block
 369                  * group */
 370                 ext4_fs_put_block_group_ref(&bg_ref);
 371                 if (rc != EOK)
 372                         return rc;
 373
 374                 ++bgid;
 375         }
 376
 377         return ENOSPC;
 378 }
 379
 380 /**
 381  * @}
 382  */