2 * Copyright (c) 2013 Grzegorz Kostka (kostka.grzegorz@gmail.com)
6 * Copyright (c) 2012 Martin Sucha
7 * Copyright (c) 2012 Frantisek Princ
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
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.
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.
34 /** @addtogroup lwext4
39 * @brief Inode allocation procedures.
42 #include "ext4_config.h"
43 #include "ext4_types.h"
44 #include "ext4_ialloc.h"
45 #include "ext4_super.h"
47 #include "ext4_blockdev.h"
48 #include "ext4_block_group.h"
49 #include "ext4_bitmap.h"
51 /**@brief Convert i-node number to relative index in block group.
52 * @param sb Superblock
53 * @param inode I-node number to be converted
54 * @return Index of the i-node in the block group
56 static uint32_t ext4_ialloc_inode2index_in_group(struct ext4_sblock *sb,
59 uint32_t inodes_per_group = ext4_get32(sb, inodes_per_group);
60 return (inode - 1) % inodes_per_group;
63 /**@brief Convert relative index of i-node to absolute i-node number.
64 * @param sb Superblock
65 * @param index Index to be converted
66 * @return Absolute number of the i-node
69 static uint32_t ext4_ialloc_index_in_group2inode(struct ext4_sblock *sb,
70 uint32_t index, uint32_t bgid)
72 uint32_t inodes_per_group = ext4_get32(sb, inodes_per_group);
73 return bgid * inodes_per_group + (index + 1);
76 /**@brief Compute block group number from the i-node number.
77 * @param sb Superblock
78 * @param inode I-node number to be found the block group for
79 * @return Block group number computed from i-node number
81 static uint32_t ext4_ialloc_get_bgid_of_inode(struct ext4_sblock *sb,
84 uint32_t inodes_per_group = ext4_get32(sb, inodes_per_group);
85 return (inode - 1) / inodes_per_group;
88 int ext4_ialloc_free_inode(struct ext4_fs *fs, uint32_t index, bool is_dir)
90 struct ext4_sblock *sb = &fs->sb;
92 /* Compute index of block group and load it */
93 uint32_t block_group = ext4_ialloc_get_bgid_of_inode(sb, index);
95 struct ext4_block_group_ref bg_ref;
96 int rc = ext4_fs_get_block_group_ref(fs, block_group, &bg_ref);
100 /* Load i-node bitmap */
101 uint32_t bitmap_block_addr =
102 ext4_bg_get_inode_bitmap(bg_ref.block_group, sb);
104 struct ext4_block bitmap_block;
105 rc = ext4_block_get(fs->bdev, &bitmap_block, bitmap_block_addr);
109 /* Free i-node in the bitmap */
110 uint32_t index_in_group = ext4_ialloc_inode2index_in_group(sb, index);
111 ext4_bmap_bit_clr(bitmap_block.data, index_in_group);
112 bitmap_block.dirty = true;
114 /* Put back the block with bitmap */
115 rc = ext4_block_set(fs->bdev, &bitmap_block);
117 /* Error in saving bitmap */
118 ext4_fs_put_block_group_ref(&bg_ref);
122 /* If released i-node is a directory, decrement used directories count
125 uint32_t bg_used_dirs =
126 ext4_bg_get_used_dirs_count(bg_ref.block_group, sb);
128 ext4_bg_set_used_dirs_count(bg_ref.block_group, sb,
132 /* Update block group free inodes count */
133 uint32_t free_inodes =
134 ext4_bg_get_free_inodes_count(bg_ref.block_group, sb);
136 ext4_bg_set_free_inodes_count(bg_ref.block_group, sb, free_inodes);
140 /* Put back the modified block group */
141 rc = ext4_fs_put_block_group_ref(&bg_ref);
145 /* Update superblock free inodes count */
146 ext4_set32(sb, free_inodes_count,
147 ext4_get32(sb, free_inodes_count) + 1);
152 int ext4_ialloc_alloc_inode(struct ext4_fs *fs, uint32_t *index, bool is_dir)
154 struct ext4_sblock *sb = &fs->sb;
156 uint32_t bgid = fs->last_inode_bg_id;
157 uint32_t bg_count = ext4_block_group_cnt(sb);
158 uint32_t sb_free_inodes = ext4_get32(sb, free_inodes_count);
161 /* Try to find free i-node in all block groups */
162 while (bgid <= bg_count) {
164 if (bgid == bg_count) {
167 bg_count = fs->last_inode_bg_id;
173 /* Load block group to check */
174 struct ext4_block_group_ref bg_ref;
175 int rc = ext4_fs_get_block_group_ref(fs, bgid, &bg_ref);
179 struct ext4_bgroup *bg = bg_ref.block_group;
181 /* Read necessary values for algorithm */
182 uint32_t free_inodes = ext4_bg_get_free_inodes_count(bg, sb);
183 uint32_t used_dirs = ext4_bg_get_used_dirs_count(bg, sb);
185 /* Check if this block group is good candidate for allocation */
186 if (free_inodes > 0) {
187 /* Load block with bitmap */
188 uint32_t bitmap_block_addr =
189 ext4_bg_get_inode_bitmap(bg_ref.block_group, sb);
191 struct ext4_block bitmap_block;
192 rc = ext4_block_get(fs->bdev, &bitmap_block,
195 ext4_fs_put_block_group_ref(&bg_ref);
199 /* Try to allocate i-node in the bitmap */
200 uint32_t inodes_in_group =
201 ext4_inodes_in_group_cnt(sb, bgid);
202 uint32_t index_in_group;
204 rc = ext4_bmap_bit_find_clr(bitmap_block.data, 0,
207 /* Block group has not any free i-node */
209 rc = ext4_block_set(fs->bdev, &bitmap_block);
211 ext4_fs_put_block_group_ref(&bg_ref);
215 rc = ext4_fs_put_block_group_ref(&bg_ref);
222 ext4_bmap_bit_set(bitmap_block.data, index_in_group);
224 /* Free i-node found, save the bitmap */
225 bitmap_block.dirty = true;
227 ext4_block_set(fs->bdev, &bitmap_block);
229 ext4_fs_put_block_group_ref(&bg_ref);
233 /* Modify filesystem counters */
235 ext4_bg_set_free_inodes_count(bg, sb, free_inodes);
237 /* Increment used directories counter */
240 ext4_bg_set_used_dirs_count(bg, sb, used_dirs);
243 /* Decrease unused inodes count */
244 if (ext4_bg_has_flag(bg,
245 EXT4_BLOCK_GROUP_ITABLE_ZEROED)) {
247 ext4_bg_get_itable_unused(bg, sb);
249 uint32_t inodes_in_group =
250 ext4_inodes_in_group_cnt(sb, bgid);
252 uint32_t free = inodes_in_group - unused;
254 if (index_in_group >= free) {
255 unused = inodes_in_group -
256 (index_in_group + 1);
257 ext4_bg_set_itable_unused(bg, sb,
262 /* Save modified block group */
265 rc = ext4_fs_put_block_group_ref(&bg_ref);
269 /* Update superblock */
271 ext4_set32(sb, free_inodes_count, sb_free_inodes);
273 /* Compute the absolute i-nodex number */
274 *index = ext4_ialloc_index_in_group2inode(
275 sb, index_in_group, bgid);
277 fs->last_inode_bg_id = bgid;
282 /* Block group not modified, put it and jump to the next block
284 ext4_fs_put_block_group_ref(&bg_ref);