2 * Copyright (c) 2013 Grzegorz Kostka (kostka.grzegorz@gmail.com)
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6 * Copyright (c) 2012 Martin Sucha
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7 * Copyright (c) 2012 Frantisek Princ
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8 * All rights reserved.
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10 * Redistribution and use in source and binary forms, with or without
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11 * modification, are permitted provided that the following conditions
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14 * - Redistributions of source code must retain the above copyright
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15 * notice, this list of conditions and the following disclaimer.
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16 * - Redistributions in binary form must reproduce the above copyright
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17 * notice, this list of conditions and the following disclaimer in the
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18 * documentation and/or other materials provided with the distribution.
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19 * - The name of the author may not be used to endorse or promote products
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20 * derived from this software without specific prior written permission.
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22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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34 /** @addtogroup lwext4
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38 * @file ext4_ialloc.c
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39 * @brief Inode allocation procedures.
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42 #include <ext4_config.h>
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43 #include <ext4_types.h>
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44 #include <ext4_ialloc.h>
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45 #include <ext4_super.h>
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46 #include <ext4_fs.h>
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47 #include <ext4_blockdev.h>
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48 #include <ext4_block_group.h>
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49 #include <ext4_bitmap.h>
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51 static uint32_t ext4_ialloc_inode2index_in_group(struct ext4_sblock *sb,
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54 uint32_t inodes_per_group = ext4_get32(sb, inodes_per_group);
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55 return (inode - 1) % inodes_per_group;
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58 static uint32_t ext4_ialloc_index_in_group2inode(struct ext4_sblock *sb,
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59 uint32_t index, uint32_t bgid)
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61 uint32_t inodes_per_group = ext4_get32(sb, inodes_per_group);
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62 return bgid * inodes_per_group + (index + 1);
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65 static uint32_t ext4_ialloc_get_bgid_of_inode(struct ext4_sblock *sb,
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68 uint32_t inodes_per_group = ext4_get32(sb, inodes_per_group);
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69 return (inode - 1) / inodes_per_group;
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73 int ext4_ialloc_free_inode(struct ext4_fs *fs, uint32_t index, bool is_dir)
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75 struct ext4_sblock *sb = &fs->sb;
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77 /* Compute index of block group and load it */
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78 uint32_t block_group = ext4_ialloc_get_bgid_of_inode(sb, index);
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80 struct ext4_block_group_ref bg_ref;
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81 int rc = ext4_fs_get_block_group_ref(fs, block_group, &bg_ref);
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85 /* Load i-node bitmap */
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86 uint32_t bitmap_block_addr = ext4_bg_get_inode_bitmap(
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87 bg_ref.block_group, sb);
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89 struct ext4_block bitmap_block;
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90 rc = ext4_block_get(fs->bdev, &bitmap_block, bitmap_block_addr);
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94 /* Free i-node in the bitmap */
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95 uint32_t index_in_group = ext4_ialloc_inode2index_in_group(sb, index);
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96 ext4_bmap_bit_clr(bitmap_block.data, index_in_group);
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97 bitmap_block.dirty = true;
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99 /* Put back the block with bitmap */
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100 rc = ext4_block_set(fs->bdev, &bitmap_block);
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102 /* Error in saving bitmap */
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103 ext4_fs_put_block_group_ref(&bg_ref);
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107 /* If released i-node is a directory, decrement used directories count */
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109 uint32_t bg_used_dirs = ext4_bg_get_used_dirs_count(
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110 bg_ref.block_group, sb);
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112 ext4_bg_set_used_dirs_count(bg_ref.block_group, sb,
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116 /* Update block group free inodes count */
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117 uint32_t free_inodes = ext4_bg_get_free_inodes_count(
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118 bg_ref.block_group, sb);
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120 ext4_bg_set_free_inodes_count(bg_ref.block_group, sb,
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123 bg_ref.dirty = true;
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125 /* Put back the modified block group */
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126 rc = ext4_fs_put_block_group_ref(&bg_ref);
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130 /* Update superblock free inodes count */
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131 ext4_set32(sb, free_inodes_count, ext4_get32(sb, free_inodes_count) + 1);
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136 int ext4_ialloc_alloc_inode(struct ext4_fs *fs, uint32_t *index, bool is_dir)
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138 struct ext4_sblock *sb = &fs->sb;
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140 uint32_t bgid = fs->last_inode_bg_id;
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141 uint32_t bg_count = ext4_block_group_cnt(sb);
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142 uint32_t sb_free_inodes = ext4_get32(sb, free_inodes_count);
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143 uint32_t avg_free_inodes = sb_free_inodes / bg_count;
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144 bool rewind = false;
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146 /* Try to find free i-node in all block groups */
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147 while (bgid <= bg_count) {
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149 if(bgid == bg_count){
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152 bg_count = fs->last_inode_bg_id;
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158 /* Load block group to check */
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159 struct ext4_block_group_ref bg_ref;
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160 int rc = ext4_fs_get_block_group_ref(fs, bgid, &bg_ref);
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164 struct ext4_bgroup *bg = bg_ref.block_group;
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166 /* Read necessary values for algorithm */
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167 uint32_t free_inodes = ext4_bg_get_free_inodes_count(bg, sb);
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168 uint32_t used_dirs = ext4_bg_get_used_dirs_count(bg, sb);
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170 /* Check if this block group is good candidate for allocation */
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171 if (free_inodes >= avg_free_inodes) {
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172 /* Load block with bitmap */
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173 uint32_t bitmap_block_addr = ext4_bg_get_inode_bitmap(
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174 bg_ref.block_group, sb);
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176 struct ext4_block bitmap_block;
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177 rc = ext4_block_get(fs->bdev, &bitmap_block, bitmap_block_addr);
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181 /* Try to allocate i-node in the bitmap */
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182 uint32_t inodes_in_group = ext4_inodes_in_group_cnt(sb, bgid);
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183 uint32_t index_in_group;
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185 rc = ext4_bmap_bit_find_clr(bitmap_block.data, 0, inodes_in_group,
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187 /* Block group has not any free i-node */
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188 if (rc == ENOSPC) {
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189 ext4_block_set(fs->bdev, &bitmap_block);
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190 ext4_fs_put_block_group_ref(&bg_ref);
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194 ext4_bmap_bit_set(bitmap_block.data, index_in_group);
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196 /* Free i-node found, save the bitmap */
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197 bitmap_block.dirty = true;
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199 ext4_block_set(fs->bdev, &bitmap_block);
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203 /* Modify filesystem counters */
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205 ext4_bg_set_free_inodes_count(bg, sb, free_inodes);
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207 /* Increment used directories counter */
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210 ext4_bg_set_used_dirs_count(bg, sb, used_dirs);
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213 /* Decrease unused inodes count */
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214 if (ext4_bg_has_flag(bg,
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215 EXT4_BLOCK_GROUP_ITABLE_ZEROED)) {
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217 ext4_bg_get_itable_unused(bg, sb);
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219 uint32_t inodes_in_group =
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220 ext4_inodes_in_group_cnt(sb, bgid);
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222 uint32_t free = inodes_in_group - unused;
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224 if (index_in_group >= free) {
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225 unused = inodes_in_group - (index_in_group + 1);
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226 ext4_bg_set_itable_unused(bg, sb, unused);
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230 /* Save modified block group */
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231 bg_ref.dirty = true;
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233 rc = ext4_fs_put_block_group_ref(&bg_ref);
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237 /* Update superblock */
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239 ext4_set32(sb, free_inodes_count, sb_free_inodes);
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242 /* Compute the absolute i-nodex number */
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243 *index = ext4_ialloc_index_in_group2inode(sb,
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244 index_in_group, bgid);
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246 fs->last_inode_bg_id = bgid;
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251 /* Block group not modified, put it and jump to the next block group */
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252 ext4_fs_put_block_group_ref(&bg_ref);
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