lwext4/ext4_ialloc.c

   1 /*\r
   2  * Copyright (c) 2013 Grzegorz Kostka (kostka.grzegorz@gmail.com)\r
   3  *\r
   4  *\r
   5  * HelenOS:\r
   6  * Copyright (c) 2012 Martin Sucha\r
   7  * Copyright (c) 2012 Frantisek Princ\r
   8  * All rights reserved.\r
   9  *\r
  10  * Redistribution and use in source and binary forms, with or without\r
  11  * modification, are permitted provided that the following conditions\r
  12  * are met:\r
  13  *\r
  14  * - Redistributions of source code must retain the above copyright\r
  15  *   notice, this list of conditions and the following disclaimer.\r
  16  * - Redistributions in binary form must reproduce the above copyright\r
  17  *   notice, this list of conditions and the following disclaimer in the\r
  18  *   documentation and/or other materials provided with the distribution.\r
  19  * - The name of the author may not be used to endorse or promote products\r
  20  *   derived from this software without specific prior written permission.\r
  21  *\r
  22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR\r
  23  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES\r
  24  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.\r
  25  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,\r
  26  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT\r
  27  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,\r
  28  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY\r
  29  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT\r
  30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF\r
  31  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.\r
  32  */\r
  33 \r
  34 /** @addtogroup lwext4\r
  35  * @{\r
  36  */\r
  37 /**\r
  38  * @file  ext4_ialloc.c\r
  39  * @brief Inode allocation procedures.\r
  40  */\r
  41 \r
  42 #include "ext4_config.h"\r
  43 #include "ext4_types.h"\r
  44 #include "ext4_ialloc.h"\r
  45 #include "ext4_super.h"\r
  46 #include "ext4_fs.h"\r
  47 #include "ext4_blockdev.h"\r
  48 #include "ext4_block_group.h"\r
  49 #include "ext4_bitmap.h"\r
  50 \r
  51 /**@brief  Convert i-node number to relative index in block group.\r
  52  * @param sb    Superblock\r
  53  * @param inode I-node number to be converted\r
  54  * @return Index of the i-node in the block group\r
  55  */\r
  56 static uint32_t ext4_ialloc_inode2index_in_group(struct ext4_sblock *sb,\r
  57                                                  uint32_t inode)\r
  58 {\r
  59         uint32_t inodes_per_group = ext4_get32(sb, inodes_per_group);\r
  60         return (inode - 1) % inodes_per_group;\r
  61 }\r
  62 \r
  63 /**@brief Convert relative index of i-node to absolute i-node number.\r
  64  * @param sb    Superblock\r
  65  * @param index Index to be converted\r
  66  * @return Absolute number of the i-node\r
  67  *\r
  68  */\r
  69 static uint32_t ext4_ialloc_index_in_group2inode(struct ext4_sblock *sb,\r
  70                                                  uint32_t index, uint32_t bgid)\r
  71 {\r
  72         uint32_t inodes_per_group = ext4_get32(sb, inodes_per_group);\r
  73         return bgid * inodes_per_group + (index + 1);\r
  74 }\r
  75 \r
  76 /**@brief Compute block group number from the i-node number.\r
  77  * @param sb    Superblock\r
  78  * @param inode I-node number to be found the block group for\r
  79  * @return Block group number computed from i-node number\r
  80  */\r
  81 static uint32_t ext4_ialloc_get_bgid_of_inode(struct ext4_sblock *sb,\r
  82                                               uint32_t inode)\r
  83 {\r
  84         uint32_t inodes_per_group = ext4_get32(sb, inodes_per_group);\r
  85         return (inode - 1) / inodes_per_group;\r
  86 }\r
  87 \r
  88 int ext4_ialloc_free_inode(struct ext4_fs *fs, uint32_t index, bool is_dir)\r
  89 {\r
  90         struct ext4_sblock *sb = &fs->sb;\r
  91 \r
  92         /* Compute index of block group and load it */\r
  93         uint32_t block_group = ext4_ialloc_get_bgid_of_inode(sb, index);\r
  94 \r
  95         struct ext4_block_group_ref bg_ref;\r
  96         int rc = ext4_fs_get_block_group_ref(fs, block_group, &bg_ref);\r
  97         if (rc != EOK)\r
  98                 return rc;\r
  99 \r
 100         /* Load i-node bitmap */\r
 101         uint32_t bitmap_block_addr =\r
 102             ext4_bg_get_inode_bitmap(bg_ref.block_group, sb);\r
 103 \r
 104         struct ext4_block bitmap_block;\r
 105         rc = ext4_block_get(fs->bdev, &bitmap_block, bitmap_block_addr);\r
 106         if (rc != EOK)\r
 107                 return rc;\r
 108 \r
 109         /* Free i-node in the bitmap */\r
 110         uint32_t index_in_group = ext4_ialloc_inode2index_in_group(sb, index);\r
 111         ext4_bmap_bit_clr(bitmap_block.data, index_in_group);\r
 112         bitmap_block.dirty = true;\r
 113 \r
 114         /* Put back the block with bitmap */\r
 115         rc = ext4_block_set(fs->bdev, &bitmap_block);\r
 116         if (rc != EOK) {\r
 117                 /* Error in saving bitmap */\r
 118                 ext4_fs_put_block_group_ref(&bg_ref);\r
 119                 return rc;\r
 120         }\r
 121 \r
 122         /* If released i-node is a directory, decrement used directories count\r
 123          */\r
 124         if (is_dir) {\r
 125                 uint32_t bg_used_dirs =\r
 126                     ext4_bg_get_used_dirs_count(bg_ref.block_group, sb);\r
 127                 bg_used_dirs--;\r
 128                 ext4_bg_set_used_dirs_count(bg_ref.block_group, sb,\r
 129                                             bg_used_dirs);\r
 130         }\r
 131 \r
 132         /* Update block group free inodes count */\r
 133         uint32_t free_inodes =\r
 134             ext4_bg_get_free_inodes_count(bg_ref.block_group, sb);\r
 135         free_inodes++;\r
 136         ext4_bg_set_free_inodes_count(bg_ref.block_group, sb, free_inodes);\r
 137 \r
 138         bg_ref.dirty = true;\r
 139 \r
 140         /* Put back the modified block group */\r
 141         rc = ext4_fs_put_block_group_ref(&bg_ref);\r
 142         if (rc != EOK)\r
 143                 return rc;\r
 144 \r
 145         /* Update superblock free inodes count */\r
 146         ext4_set32(sb, free_inodes_count,\r
 147                    ext4_get32(sb, free_inodes_count) + 1);\r
 148 \r
 149         return EOK;\r
 150 }\r
 151 \r
 152 int ext4_ialloc_alloc_inode(struct ext4_fs *fs, uint32_t *index, bool is_dir)\r
 153 {\r
 154         struct ext4_sblock *sb = &fs->sb;\r
 155 \r
 156         uint32_t bgid = fs->last_inode_bg_id;\r
 157         uint32_t bg_count = ext4_block_group_cnt(sb);\r
 158         uint32_t sb_free_inodes = ext4_get32(sb, free_inodes_count);\r
 159         bool rewind = false;\r
 160 \r
 161         /* Try to find free i-node in all block groups */\r
 162         while (bgid <= bg_count) {\r
 163 \r
 164                 if (bgid == bg_count) {\r
 165                         if (rewind)\r
 166                                 break;\r
 167                         bg_count = fs->last_inode_bg_id;\r
 168                         bgid = 0;\r
 169                         rewind = true;\r
 170                         continue;\r
 171                 }\r
 172 \r
 173                 /* Load block group to check */\r
 174                 struct ext4_block_group_ref bg_ref;\r
 175                 int rc = ext4_fs_get_block_group_ref(fs, bgid, &bg_ref);\r
 176                 if (rc != EOK)\r
 177                         return rc;\r
 178 \r
 179                 struct ext4_bgroup *bg = bg_ref.block_group;\r
 180 \r
 181                 /* Read necessary values for algorithm */\r
 182                 uint32_t free_inodes = ext4_bg_get_free_inodes_count(bg, sb);\r
 183                 uint32_t used_dirs = ext4_bg_get_used_dirs_count(bg, sb);\r
 184 \r
 185                 /* Check if this block group is good candidate for allocation */\r
 186                 if (free_inodes > 0) {\r
 187                         /* Load block with bitmap */\r
 188                         uint32_t bitmap_block_addr =\r
 189                             ext4_bg_get_inode_bitmap(bg_ref.block_group, sb);\r
 190 \r
 191                         struct ext4_block bitmap_block;\r
 192                         rc = ext4_block_get(fs->bdev, &bitmap_block,\r
 193                                             bitmap_block_addr);\r
 194                         if (rc != EOK) {\r
 195                                 ext4_fs_put_block_group_ref(&bg_ref);\r
 196                                 return rc;\r
 197                         }\r
 198 \r
 199                         /* Try to allocate i-node in the bitmap */\r
 200                         uint32_t inodes_in_group =\r
 201                             ext4_inodes_in_group_cnt(sb, bgid);\r
 202                         uint32_t index_in_group;\r
 203 \r
 204                         rc = ext4_bmap_bit_find_clr(bitmap_block.data, 0,\r
 205                                                     inodes_in_group,\r
 206                                                     &index_in_group);\r
 207                         /* Block group has not any free i-node */\r
 208                         if (rc == ENOSPC) {\r
 209                                 rc = ext4_block_set(fs->bdev, &bitmap_block);\r
 210                                 if (rc != EOK) {\r
 211                                         ext4_fs_put_block_group_ref(&bg_ref);\r
 212                                         return rc;\r
 213                                 }\r
 214 \r
 215                                 rc = ext4_fs_put_block_group_ref(&bg_ref);\r
 216                                 if (rc != EOK)\r
 217                                         return rc;\r
 218 \r
 219                                 continue;\r
 220                         }\r
 221 \r
 222                         ext4_bmap_bit_set(bitmap_block.data, index_in_group);\r
 223 \r
 224                         /* Free i-node found, save the bitmap */\r
 225                         bitmap_block.dirty = true;\r
 226 \r
 227                         ext4_block_set(fs->bdev, &bitmap_block);\r
 228                         if (rc != EOK) {\r
 229                                 ext4_fs_put_block_group_ref(&bg_ref);\r
 230                                 return rc;\r
 231                         }\r
 232 \r
 233                         /* Modify filesystem counters */\r
 234                         free_inodes--;\r
 235                         ext4_bg_set_free_inodes_count(bg, sb, free_inodes);\r
 236 \r
 237                         /* Increment used directories counter */\r
 238                         if (is_dir) {\r
 239                                 used_dirs++;\r
 240                                 ext4_bg_set_used_dirs_count(bg, sb, used_dirs);\r
 241                         }\r
 242 \r
 243                         /* Decrease unused inodes count */\r
 244                         if (ext4_bg_has_flag(bg,\r
 245                                              EXT4_BLOCK_GROUP_ITABLE_ZEROED)) {\r
 246                                 uint32_t unused =\r
 247                                     ext4_bg_get_itable_unused(bg, sb);\r
 248 \r
 249                                 uint32_t inodes_in_group =\r
 250                                     ext4_inodes_in_group_cnt(sb, bgid);\r
 251 \r
 252                                 uint32_t free = inodes_in_group - unused;\r
 253 \r
 254                                 if (index_in_group >= free) {\r
 255                                         unused = inodes_in_group -\r
 256                                                  (index_in_group + 1);\r
 257                                         ext4_bg_set_itable_unused(bg, sb,\r
 258                                                                   unused);\r
 259                                 }\r
 260                         }\r
 261 \r
 262                         /* Save modified block group */\r
 263                         bg_ref.dirty = true;\r
 264 \r
 265                         rc = ext4_fs_put_block_group_ref(&bg_ref);\r
 266                         if (rc != EOK)\r
 267                                 return rc;\r
 268 \r
 269                         /* Update superblock */\r
 270                         sb_free_inodes--;\r
 271                         ext4_set32(sb, free_inodes_count, sb_free_inodes);\r
 272 \r
 273                         /* Compute the absolute i-nodex number */\r
 274                         *index = ext4_ialloc_index_in_group2inode(\r
 275                             sb, index_in_group, bgid);\r
 276 \r
 277                         fs->last_inode_bg_id = bgid;\r
 278 \r
 279                         return EOK;\r
 280                 }\r
 281 \r
 282                 /* Block group not modified, put it and jump to the next block\r
 283                  * group */\r
 284                 ext4_fs_put_block_group_ref(&bg_ref);\r
 285                 if (rc != EOK)\r
 286                         return rc;\r
 287 \r
 288                 ++bgid;\r
 289         }\r
 290 \r
 291         return ENOSPC;\r
 292 }\r
 293 \r
 294 /**\r
 295  * @}\r
 296  */\r