src/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_misc.h>
  45 #include <ext4_errno.h>
  46 #include <ext4_debug.h>
  47
  48 #include <ext4_trans.h>
  49 #include <ext4_ialloc.h>
  50 #include <ext4_super.h>
  51 #include <ext4_crc32.h>
  52 #include <ext4_fs.h>
  53 #include <ext4_blockdev.h>
  54 #include <ext4_block_group.h>
  55 #include <ext4_bitmap.h>
  56
  57 /**@brief  Convert i-node number to relative index in block group.
  58  * @param sb    Superblock
  59  * @param inode I-node number to be converted
  60  * @return Index of the i-node in the block group
  61  */
  62 static uint32_t ext4_ialloc_inode_to_bgidx(struct ext4_sblock *sb,
  63                                            uint32_t inode)
  64 {
  65         uint32_t inodes_per_group = ext4_get32(sb, inodes_per_group);
  66         return (inode - 1) % inodes_per_group;
  67 }
  68
  69 /**@brief Convert relative index of i-node to absolute i-node number.
  70  * @param sb    Superblock
  71  * @param index Index to be converted
  72  * @return Absolute number of the i-node
  73  *
  74  */
  75 static uint32_t ext4_ialloc_bgidx_to_inode(struct ext4_sblock *sb,
  76                                            uint32_t index, uint32_t bgid)
  77 {
  78         uint32_t inodes_per_group = ext4_get32(sb, inodes_per_group);
  79         return bgid * inodes_per_group + (index + 1);
  80 }
  81
  82 /**@brief Compute block group number from the i-node number.
  83  * @param sb    Superblock
  84  * @param inode I-node number to be found the block group for
  85  * @return Block group number computed from i-node number
  86  */
  87 static uint32_t ext4_ialloc_get_bgid_of_inode(struct ext4_sblock *sb,
  88                                               uint32_t inode)
  89 {
  90         uint32_t inodes_per_group = ext4_get32(sb, inodes_per_group);
  91         return (inode - 1) / inodes_per_group;
  92 }
  93
  94 #if CONFIG_META_CSUM_ENABLE
  95 static uint32_t ext4_ialloc_bitmap_csum(struct ext4_sblock *sb, void *bitmap)
  96 {
  97         uint32_t csum = 0;
  98         if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
  99                 uint32_t inodes_per_group =
 100                         ext4_get32(sb, inodes_per_group);
 101
 102                 /* First calculate crc32 checksum against fs uuid */
 103                 csum = ext4_crc32c(EXT4_CRC32_INIT, sb->uuid, sizeof(sb->uuid));
 104                 /* Then calculate crc32 checksum against inode bitmap */
 105                 csum = ext4_crc32c(csum, bitmap, (inodes_per_group + 7) / 8);
 106         }
 107         return csum;
 108 }
 109 #else
 110 #define ext4_ialloc_bitmap_csum(...) 0
 111 #endif
 112
 113 void ext4_ialloc_set_bitmap_csum(struct ext4_sblock *sb, struct ext4_bgroup *bg,
 114                                  void *bitmap __unused)
 115 {
 116         int desc_size = ext4_sb_get_desc_size(sb);
 117         uint32_t csum = ext4_ialloc_bitmap_csum(sb, bitmap);
 118         uint16_t lo_csum = to_le16(csum & 0xFFFF),
 119                  hi_csum = to_le16(csum >> 16);
 120
 121         if (!ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM))
 122                 return;
 123
 124         /* See if we need to assign a 32bit checksum */
 125         bg->inode_bitmap_csum_lo = lo_csum;
 126         if (desc_size == EXT4_MAX_BLOCK_GROUP_DESCRIPTOR_SIZE)
 127                 bg->inode_bitmap_csum_hi = hi_csum;
 128
 129 }
 130
 131 #if CONFIG_META_CSUM_ENABLE
 132 static bool
 133 ext4_ialloc_verify_bitmap_csum(struct ext4_sblock *sb, struct ext4_bgroup *bg,
 134                                void *bitmap __unused)
 135 {
 136
 137         int desc_size = ext4_sb_get_desc_size(sb);
 138         uint32_t csum = ext4_ialloc_bitmap_csum(sb, bitmap);
 139         uint16_t lo_csum = to_le16(csum & 0xFFFF),
 140                  hi_csum = to_le16(csum >> 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_csum)
 146                 return false;
 147
 148         if (desc_size == EXT4_MAX_BLOCK_GROUP_DESCRIPTOR_SIZE)
 149                 if (bg->inode_bitmap_csum_hi != hi_csum)
 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         struct ext4_bgroup *bg = bg_ref.block_group;
 171
 172         /* Load i-node bitmap */
 173         ext4_fsblk_t bitmap_block_addr =
 174             ext4_bg_get_inode_bitmap(bg, sb);
 175
 176         struct ext4_block b;
 177         rc = ext4_trans_block_get(fs->bdev, &b, bitmap_block_addr);
 178         if (rc != EOK)
 179                 return rc;
 180
 181         if (!ext4_ialloc_verify_bitmap_csum(sb, bg, b.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_inode_to_bgidx(sb, index);
 190         ext4_bmap_bit_clr(b.data, index_in_group);
 191         ext4_ialloc_set_bitmap_csum(sb, bg, b.data);
 192         ext4_trans_set_block_dirty(b.buf);
 193
 194         /* Put back the block with bitmap */
 195         rc = ext4_block_set(fs->bdev, &b);
 196         if (rc != EOK) {
 197                 /* Error in saving bitmap */
 198                 ext4_fs_put_block_group_ref(&bg_ref);
 199                 return rc;
 200         }
 201
 202         /* If released i-node is a directory, decrement used directories count
 203          */
 204         if (is_dir) {
 205                 uint32_t bg_used_dirs = ext4_bg_get_used_dirs_count(bg, sb);
 206                 bg_used_dirs--;
 207                 ext4_bg_set_used_dirs_count(bg, sb, bg_used_dirs);
 208         }
 209
 210         /* Update block group free inodes count */
 211         uint32_t free_inodes = ext4_bg_get_free_inodes_count(bg, sb);
 212         free_inodes++;
 213         ext4_bg_set_free_inodes_count(bg, sb, free_inodes);
 214
 215         bg_ref.dirty = true;
 216
 217         /* Put back the modified block group */
 218         rc = ext4_fs_put_block_group_ref(&bg_ref);
 219         if (rc != EOK)
 220                 return rc;
 221
 222         /* Update superblock free inodes count */
 223         ext4_set32(sb, free_inodes_count,
 224                    ext4_get32(sb, free_inodes_count) + 1);
 225
 226         return EOK;
 227 }
 228
 229 int ext4_ialloc_alloc_inode(struct ext4_fs *fs, uint32_t *idx, bool is_dir)
 230 {
 231         struct ext4_sblock *sb = &fs->sb;
 232
 233         uint32_t bgid = fs->last_inode_bg_id;
 234         uint32_t bg_count = ext4_block_group_cnt(sb);
 235         uint32_t sb_free_inodes = ext4_get32(sb, free_inodes_count);
 236         bool rewind = false;
 237
 238         /* Try to find free i-node in all block groups */
 239         while (bgid <= bg_count) {
 240
 241                 if (bgid == bg_count) {
 242                         if (rewind)
 243                                 break;
 244                         bg_count = fs->last_inode_bg_id;
 245                         bgid = 0;
 246                         rewind = true;
 247                         continue;
 248                 }
 249
 250                 /* Load block group to check */
 251                 struct ext4_block_group_ref bg_ref;
 252                 int rc = ext4_fs_get_block_group_ref(fs, bgid, &bg_ref);
 253                 if (rc != EOK)
 254                         return rc;
 255
 256                 struct ext4_bgroup *bg = bg_ref.block_group;
 257
 258                 /* Read necessary values for algorithm */
 259                 uint32_t free_inodes = ext4_bg_get_free_inodes_count(bg, sb);
 260                 uint32_t used_dirs = ext4_bg_get_used_dirs_count(bg, sb);
 261
 262                 /* Check if this block group is good candidate for allocation */
 263                 if (free_inodes > 0) {
 264                         /* Load block with bitmap */
 265                         ext4_fsblk_t bmp_blk_add = ext4_bg_get_inode_bitmap(bg, sb);
 266
 267                         struct ext4_block b;
 268                         rc = ext4_trans_block_get(fs->bdev, &b, bmp_blk_add);
 269                         if (rc != EOK) {
 270                                 ext4_fs_put_block_group_ref(&bg_ref);
 271                                 return rc;
 272                         }
 273
 274                         if (!ext4_ialloc_verify_bitmap_csum(sb, bg, b.data)) {
 275                                 ext4_dbg(DEBUG_IALLOC,
 276                                         DBG_WARN "Bitmap checksum failed."
 277                                         "Group: %" PRIu32"\n",
 278                                         bg_ref.index);
 279                         }
 280
 281                         /* Try to allocate i-node in the bitmap */
 282                         uint32_t inodes_in_bg;
 283                         uint32_t idx_in_bg;
 284
 285                         inodes_in_bg = ext4_inodes_in_group_cnt(sb, bgid);
 286                         rc = ext4_bmap_bit_find_clr(b.data, 0, inodes_in_bg,
 287                                                     &idx_in_bg);
 288                         /* Block group has not any free i-node */
 289                         if (rc == ENOSPC) {
 290                                 rc = ext4_block_set(fs->bdev, &b);
 291                                 if (rc != EOK) {
 292                                         ext4_fs_put_block_group_ref(&bg_ref);
 293                                         return rc;
 294                                 }
 295
 296                                 rc = ext4_fs_put_block_group_ref(&bg_ref);
 297                                 if (rc != EOK)
 298                                         return rc;
 299
 300                                 continue;
 301                         }
 302
 303                         ext4_bmap_bit_set(b.data, idx_in_bg);
 304
 305                         /* Free i-node found, save the bitmap */
 306                         ext4_ialloc_set_bitmap_csum(sb,bg,
 307                                                     b.data);
 308                         ext4_trans_set_block_dirty(b.buf);
 309
 310                         ext4_block_set(fs->bdev, &b);
 311                         if (rc != EOK) {
 312                                 ext4_fs_put_block_group_ref(&bg_ref);
 313                                 return rc;
 314                         }
 315
 316                         /* Modify filesystem counters */
 317                         free_inodes--;
 318                         ext4_bg_set_free_inodes_count(bg, sb, free_inodes);
 319
 320                         /* Increment used directories counter */
 321                         if (is_dir) {
 322                                 used_dirs++;
 323                                 ext4_bg_set_used_dirs_count(bg, sb, used_dirs);
 324                         }
 325
 326                         /* Decrease unused inodes count */
 327                         uint32_t unused =
 328                             ext4_bg_get_itable_unused(bg, sb);
 329
 330                         uint32_t free = inodes_in_bg - unused;
 331
 332                         if (idx_in_bg >= free) {
 333                                 unused = inodes_in_bg - (idx_in_bg + 1);
 334                                 ext4_bg_set_itable_unused(bg, sb, unused);
 335                         }
 336
 337                         /* Save modified block group */
 338                         bg_ref.dirty = true;
 339
 340                         rc = ext4_fs_put_block_group_ref(&bg_ref);
 341                         if (rc != EOK)
 342                                 return rc;
 343
 344                         /* Update superblock */
 345                         sb_free_inodes--;
 346                         ext4_set32(sb, free_inodes_count, sb_free_inodes);
 347
 348                         /* Compute the absolute i-nodex number */
 349                         *idx = ext4_ialloc_bgidx_to_inode(sb, idx_in_bg, bgid);
 350
 351                         fs->last_inode_bg_id = bgid;
 352
 353                         return EOK;
 354                 }
 355
 356                 /* Block group not modified, put it and jump to the next block
 357                  * group */
 358                 ext4_fs_put_block_group_ref(&bg_ref);
 359                 if (rc != EOK)
 360                         return rc;
 361
 362                 ++bgid;
 363         }
 364
 365         return ENOSPC;
 366 }
 367
 368 /**
 369  * @}
 370  */