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_inode_to_bgidx(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_bgidx_to_inode(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, void *bitmap)
  91 {
  92         uint32_t csum = 0;
  93         if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
  94                 uint32_t inodes_per_group =
  95                         ext4_get32(sb, inodes_per_group);
  96
  97                 /* First calculate crc32 checksum against fs uuid */
  98                 csum = ext4_crc32c(EXT4_CRC32_INIT, sb->uuid, sizeof(sb->uuid));
  99                 /* Then calculate crc32 checksum against inode bitmap */
 100                 csum = ext4_crc32c(csum, bitmap, (inodes_per_group + 7) / 8);
 101         }
 102         return csum;
 103 }
 104 #else
 105 #define ext4_ialloc_bitmap_csum(...) 0
 106 #endif
 107
 108 void ext4_ialloc_set_bitmap_csum(struct ext4_sblock *sb, struct ext4_bgroup *bg,
 109                                  void *bitmap __unused)
 110 {
 111         int desc_size = ext4_sb_get_desc_size(sb);
 112         uint32_t csum = ext4_ialloc_bitmap_csum(sb, bitmap);
 113         uint16_t lo_csum = to_le16(csum & 0xFFFF),
 114                  hi_csum = to_le16(csum >> 16);
 115
 116         if (!ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM))
 117                 return;
 118
 119         /* See if we need to assign a 32bit checksum */
 120         bg->inode_bitmap_csum_lo = lo_csum;
 121         if (desc_size == EXT4_MAX_BLOCK_GROUP_DESCRIPTOR_SIZE)
 122                 bg->inode_bitmap_csum_hi = hi_csum;
 123
 124 }
 125
 126 #if CONFIG_META_CSUM_ENABLE
 127 static bool
 128 ext4_ialloc_verify_bitmap_csum(struct ext4_sblock *sb, struct ext4_bgroup *bg,
 129                                void *bitmap __unused)
 130 {
 131
 132         int desc_size = ext4_sb_get_desc_size(sb);
 133         uint32_t csum = ext4_ialloc_bitmap_csum(sb, bitmap);
 134         uint16_t lo_csum = to_le16(csum & 0xFFFF),
 135                  hi_csum = to_le16(csum >> 16);
 136
 137         if (!ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM))
 138                 return true;
 139
 140         if (bg->inode_bitmap_csum_lo != lo_csum)
 141                 return false;
 142
 143         if (desc_size == EXT4_MAX_BLOCK_GROUP_DESCRIPTOR_SIZE)
 144                 if (bg->inode_bitmap_csum_hi != hi_csum)
 145                         return false;
 146
 147         return true;
 148 }
 149 #else
 150 #define ext4_ialloc_verify_bitmap_csum(...) true
 151 #endif
 152
 153 int ext4_ialloc_free_inode(struct ext4_fs *fs, uint32_t index, bool is_dir)
 154 {
 155         struct ext4_sblock *sb = &fs->sb;
 156
 157         /* Compute index of block group and load it */
 158         uint32_t block_group = ext4_ialloc_get_bgid_of_inode(sb, index);
 159
 160         struct ext4_block_group_ref bg_ref;
 161         int rc = ext4_fs_get_block_group_ref(fs, block_group, &bg_ref);
 162         if (rc != EOK)
 163                 return rc;
 164
 165         struct ext4_bgroup *bg = bg_ref.block_group;
 166
 167         /* Load i-node bitmap */
 168         uint32_t bitmap_block_addr =
 169             ext4_bg_get_inode_bitmap(bg, sb);
 170
 171         struct ext4_block b;
 172         rc = ext4_trans_block_get(fs->bdev, &b, bitmap_block_addr);
 173         if (rc != EOK)
 174                 return rc;
 175
 176         if (!ext4_ialloc_verify_bitmap_csum(sb, bg, b.data)) {
 177                 ext4_dbg(DEBUG_IALLOC,
 178                         DBG_WARN "Bitmap checksum failed."
 179                         "Group: %" PRIu32"\n",
 180                         bg_ref.index);
 181         }
 182
 183         /* Free i-node in the bitmap */
 184         uint32_t index_in_group = ext4_ialloc_inode_to_bgidx(sb, index);
 185         ext4_bmap_bit_clr(b.data, index_in_group);
 186         ext4_ialloc_set_bitmap_csum(sb, bg, b.data);
 187         ext4_trans_set_block_dirty(b.buf);
 188
 189         /* Put back the block with bitmap */
 190         rc = ext4_block_set(fs->bdev, &b);
 191         if (rc != EOK) {
 192                 /* Error in saving bitmap */
 193                 ext4_fs_put_block_group_ref(&bg_ref);
 194                 return rc;
 195         }
 196
 197         /* If released i-node is a directory, decrement used directories count
 198          */
 199         if (is_dir) {
 200                 uint32_t bg_used_dirs = ext4_bg_get_used_dirs_count(bg, sb);
 201                 bg_used_dirs--;
 202                 ext4_bg_set_used_dirs_count(bg, sb, bg_used_dirs);
 203         }
 204
 205         /* Update block group free inodes count */
 206         uint32_t free_inodes = ext4_bg_get_free_inodes_count(bg, sb);
 207         free_inodes++;
 208         ext4_bg_set_free_inodes_count(bg, sb, free_inodes);
 209
 210         bg_ref.dirty = true;
 211
 212         /* Put back the modified block group */
 213         rc = ext4_fs_put_block_group_ref(&bg_ref);
 214         if (rc != EOK)
 215                 return rc;
 216
 217         /* Update superblock free inodes count */
 218         ext4_set32(sb, free_inodes_count,
 219                    ext4_get32(sb, free_inodes_count) + 1);
 220
 221         return EOK;
 222 }
 223
 224 int ext4_ialloc_alloc_inode(struct ext4_fs *fs, uint32_t *idx, bool is_dir)
 225 {
 226         struct ext4_sblock *sb = &fs->sb;
 227
 228         uint32_t bgid = fs->last_inode_bg_id;
 229         uint32_t bg_count = ext4_block_group_cnt(sb);
 230         uint32_t sb_free_inodes = ext4_get32(sb, free_inodes_count);
 231         bool rewind = false;
 232
 233         /* Try to find free i-node in all block groups */
 234         while (bgid <= bg_count) {
 235
 236                 if (bgid == bg_count) {
 237                         if (rewind)
 238                                 break;
 239                         bg_count = fs->last_inode_bg_id;
 240                         bgid = 0;
 241                         rewind = true;
 242                         continue;
 243                 }
 244
 245                 /* Load block group to check */
 246                 struct ext4_block_group_ref bg_ref;
 247                 int rc = ext4_fs_get_block_group_ref(fs, bgid, &bg_ref);
 248                 if (rc != EOK)
 249                         return rc;
 250
 251                 struct ext4_bgroup *bg = bg_ref.block_group;
 252
 253                 /* Read necessary values for algorithm */
 254                 uint32_t free_inodes = ext4_bg_get_free_inodes_count(bg, sb);
 255                 uint32_t used_dirs = ext4_bg_get_used_dirs_count(bg, sb);
 256
 257                 /* Check if this block group is good candidate for allocation */
 258                 if (free_inodes > 0) {
 259                         /* Load block with bitmap */
 260                         uint32_t bmp_blk_add = ext4_bg_get_inode_bitmap(bg, sb);
 261
 262                         struct ext4_block b;
 263                         rc = ext4_trans_block_get(fs->bdev, &b, bmp_blk_add);
 264                         if (rc != EOK) {
 265                                 ext4_fs_put_block_group_ref(&bg_ref);
 266                                 return rc;
 267                         }
 268
 269                         if (!ext4_ialloc_verify_bitmap_csum(sb, bg, b.data)) {
 270                                 ext4_dbg(DEBUG_IALLOC,
 271                                         DBG_WARN "Bitmap checksum failed."
 272                                         "Group: %" PRIu32"\n",
 273                                         bg_ref.index);
 274                         }
 275
 276                         /* Try to allocate i-node in the bitmap */
 277                         uint32_t inodes_in_bg;
 278                         uint32_t idx_in_bg;
 279
 280                         inodes_in_bg = ext4_inodes_in_group_cnt(sb, bgid);
 281                         rc = ext4_bmap_bit_find_clr(b.data, 0, inodes_in_bg,
 282                                                     &idx_in_bg);
 283                         /* Block group has not any free i-node */
 284                         if (rc == ENOSPC) {
 285                                 rc = ext4_block_set(fs->bdev, &b);
 286                                 if (rc != EOK) {
 287                                         ext4_fs_put_block_group_ref(&bg_ref);
 288                                         return rc;
 289                                 }
 290
 291                                 rc = ext4_fs_put_block_group_ref(&bg_ref);
 292                                 if (rc != EOK)
 293                                         return rc;
 294
 295                                 continue;
 296                         }
 297
 298                         ext4_bmap_bit_set(b.data, idx_in_bg);
 299
 300                         /* Free i-node found, save the bitmap */
 301                         ext4_ialloc_set_bitmap_csum(sb,bg,
 302                                                     b.data);
 303                         ext4_trans_set_block_dirty(b.buf);
 304
 305                         ext4_block_set(fs->bdev, &b);
 306                         if (rc != EOK) {
 307                                 ext4_fs_put_block_group_ref(&bg_ref);
 308                                 return rc;
 309                         }
 310
 311                         /* Modify filesystem counters */
 312                         free_inodes--;
 313                         ext4_bg_set_free_inodes_count(bg, sb, free_inodes);
 314
 315                         /* Increment used directories counter */
 316                         if (is_dir) {
 317                                 used_dirs++;
 318                                 ext4_bg_set_used_dirs_count(bg, sb, used_dirs);
 319                         }
 320
 321                         /* Decrease unused inodes count */
 322                         uint32_t unused =
 323                             ext4_bg_get_itable_unused(bg, sb);
 324
 325                         uint32_t free = inodes_in_bg - unused;
 326
 327                         if (idx_in_bg >= free) {
 328                                 unused = inodes_in_bg - (idx_in_bg + 1);
 329                                 ext4_bg_set_itable_unused(bg, sb, unused);
 330                         }
 331
 332                         /* Save modified block group */
 333                         bg_ref.dirty = true;
 334
 335                         rc = ext4_fs_put_block_group_ref(&bg_ref);
 336                         if (rc != EOK)
 337                                 return rc;
 338
 339                         /* Update superblock */
 340                         sb_free_inodes--;
 341                         ext4_set32(sb, free_inodes_count, sb_free_inodes);
 342
 343                         /* Compute the absolute i-nodex number */
 344                         *idx = ext4_ialloc_bgidx_to_inode(sb, idx_in_bg, bgid);
 345
 346                         fs->last_inode_bg_id = bgid;
 347
 348                         return EOK;
 349                 }
 350
 351                 /* Block group not modified, put it and jump to the next block
 352                  * group */
 353                 ext4_fs_put_block_group_ref(&bg_ref);
 354                 if (rc != EOK)
 355                         return rc;
 356
 357                 ++bgid;
 358         }
 359
 360         return ENOSPC;
 361 }
 362
 363 /**
 364  * @}
 365  */