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 Physical block allocator.
42 #include "ext4_config.h"
43 #include "ext4_balloc.h"
44 #include "ext4_super.h"
45 #include "ext4_block_group.h"
47 #include "ext4_bitmap.h"
48 #include "ext4_inode.h"
50 /**@brief Compute number of block group from block address.
51 * @param sb superblock pointer.
52 * @param baddr Absolute address of block.
53 * @return Block group index
55 uint32_t ext4_balloc_get_bgid_of_block(struct ext4_sblock *s,
58 if (ext4_get32(s, first_data_block))
61 return baddr / ext4_get32(s, blocks_per_group);
64 /**@brief Compute the starting block address of a block group
65 * @param sb superblock pointer.
66 * @param bgid block group index
67 * @return Block address
69 uint32_t ext4_balloc_get_block_of_bgid(struct ext4_sblock *s,
73 if (ext4_get32(s, first_data_block))
76 baddr += bgid * ext4_get32(s, blocks_per_group);
80 int ext4_balloc_free_block(struct ext4_inode_ref *inode_ref, uint32_t baddr)
82 struct ext4_fs *fs = inode_ref->fs;
83 struct ext4_sblock *sb = &fs->sb;
85 uint32_t block_group = ext4_balloc_get_bgid_of_block(sb, baddr);
86 uint32_t index_in_group = ext4_fs_baddr2_index_in_group(sb, baddr);
88 /* Load block group reference */
89 struct ext4_block_group_ref bg_ref;
90 int rc = ext4_fs_get_block_group_ref(fs, block_group, &bg_ref);
94 /* Load block with bitmap */
95 uint32_t bitmap_block_addr =
96 ext4_bg_get_block_bitmap(bg_ref.block_group, sb);
98 struct ext4_block bitmap_block;
100 rc = ext4_block_get(fs->bdev, &bitmap_block, bitmap_block_addr);
102 ext4_fs_put_block_group_ref(&bg_ref);
107 ext4_bmap_bit_clr(bitmap_block.data, index_in_group);
108 bitmap_block.dirty = true;
110 /* Release block with bitmap */
111 rc = ext4_block_set(fs->bdev, &bitmap_block);
113 /* Error in saving bitmap */
114 ext4_fs_put_block_group_ref(&bg_ref);
118 uint32_t block_size = ext4_sb_get_block_size(sb);
120 /* Update superblock free blocks count */
121 uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
123 ext4_sb_set_free_blocks_cnt(sb, sb_free_blocks);
125 /* Update inode blocks count */
126 uint64_t ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode);
127 ino_blocks -= block_size / EXT4_INODE_BLOCK_SIZE;
128 ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
129 inode_ref->dirty = true;
131 /* Update block group free blocks count */
132 uint32_t free_blocks =
133 ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
135 ext4_bg_set_free_blocks_count(bg_ref.block_group, sb, free_blocks);
139 /* Release block group reference */
140 return ext4_fs_put_block_group_ref(&bg_ref);
143 int ext4_balloc_free_blocks(struct ext4_inode_ref *inode_ref, uint32_t first,
147 struct ext4_fs *fs = inode_ref->fs;
148 struct ext4_sblock *sb = &fs->sb;
150 /* Compute indexes */
151 uint32_t block_group_first = ext4_balloc_get_bgid_of_block(sb, first);
153 /* Compute indexes */
154 uint32_t block_group_last =
155 ext4_balloc_get_bgid_of_block(sb, first + count - 1);
157 if (!ext4_sb_has_feature_incompatible(sb,
158 EXT4_FEATURE_INCOMPAT_FLEX_BG)) {
159 /*It is not possible without flex_bg that blocks are continuous
160 * and and last block belongs to other bg.*/
161 ext4_assert(block_group_first == ext4_balloc_get_bgid_of_block(
162 sb, first + count - 1));
165 /* Load block group reference */
166 struct ext4_block_group_ref bg_ref;
167 while (block_group_first <= block_group_last) {
170 ext4_fs_get_block_group_ref(fs, block_group_first, &bg_ref);
174 uint32_t index_in_group_first =
175 ext4_fs_baddr2_index_in_group(sb, first);
177 /* Load block with bitmap */
178 uint32_t bitmap_block_addr =
179 ext4_bg_get_block_bitmap(bg_ref.block_group, sb);
181 struct ext4_block bitmap_block;
183 rc = ext4_block_get(fs->bdev, &bitmap_block, bitmap_block_addr);
185 ext4_fs_put_block_group_ref(&bg_ref);
190 ext4_sb_get_block_size(sb) * 8 - index_in_group_first;
192 /*If last block, free only count blocks*/
193 free_cnt = count > free_cnt ? free_cnt : count;
196 ext4_bmap_bits_free(bitmap_block.data, index_in_group_first,
198 bitmap_block.dirty = true;
203 /* Release block with bitmap */
204 rc = ext4_block_set(fs->bdev, &bitmap_block);
206 ext4_fs_put_block_group_ref(&bg_ref);
210 uint32_t block_size = ext4_sb_get_block_size(sb);
212 /* Update superblock free blocks count */
213 uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
214 sb_free_blocks += free_cnt;
215 ext4_sb_set_free_blocks_cnt(sb, sb_free_blocks);
217 /* Update inode blocks count */
218 uint64_t ino_blocks =
219 ext4_inode_get_blocks_count(sb, inode_ref->inode);
220 ino_blocks -= free_cnt * (block_size / EXT4_INODE_BLOCK_SIZE);
221 ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
222 inode_ref->dirty = true;
224 /* Update block group free blocks count */
225 uint32_t free_blocks =
226 ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
227 free_blocks += free_cnt;
228 ext4_bg_set_free_blocks_count(bg_ref.block_group, sb,
232 /* Release block group reference */
233 rc = ext4_fs_put_block_group_ref(&bg_ref);
240 /*All blocks should be released*/
241 ext4_assert(count == 0);
245 /**@brief Compute 'goal' for allocation algorithm.
246 * @param inode_ref Reference to inode, to allocate block for
250 static int ext4_balloc_find_goal(struct ext4_inode_ref *inode_ref,
253 struct ext4_sblock *sb = &inode_ref->fs->sb;
256 uint64_t inode_size = ext4_inode_get_size(sb, inode_ref->inode);
257 uint32_t block_size = ext4_sb_get_block_size(sb);
258 uint32_t inode_block_count = inode_size / block_size;
260 if (inode_size % block_size != 0)
263 /* If inode has some blocks, get last block address + 1 */
264 if (inode_block_count > 0) {
265 int rc = ext4_fs_get_inode_data_block_index(
266 inode_ref, inode_block_count - 1, goal);
275 /* If goal == 0, sparse file -> continue */
278 /* Identify block group of inode */
280 uint32_t inodes_per_group = ext4_get32(sb, inodes_per_group);
281 uint32_t block_group = (inode_ref->index - 1) / inodes_per_group;
282 block_size = ext4_sb_get_block_size(sb);
284 /* Load block group reference */
285 struct ext4_block_group_ref bg_ref;
287 ext4_fs_get_block_group_ref(inode_ref->fs, block_group, &bg_ref);
291 /* Compute indexes */
292 uint32_t block_group_count = ext4_block_group_cnt(sb);
293 uint32_t inode_table_first_block =
294 ext4_bg_get_inode_table_first_block(bg_ref.block_group, sb);
295 uint16_t inode_table_item_size = ext4_get16(sb, inode_size);
296 uint32_t inode_table_bytes;
298 /* Check for last block group */
299 if (block_group < block_group_count - 1) {
300 inode_table_bytes = inodes_per_group * inode_table_item_size;
302 /* Last block group could be smaller */
303 uint32_t inodes_count_total = ext4_get32(sb, inodes_count);
306 (inodes_count_total -
307 ((block_group_count - 1) * inodes_per_group)) *
308 inode_table_item_size;
311 uint32_t inode_table_blocks = inode_table_bytes / block_size;
313 if (inode_table_bytes % block_size)
314 inode_table_blocks++;
316 *goal = inode_table_first_block + inode_table_blocks;
318 return ext4_fs_put_block_group_ref(&bg_ref);
321 int ext4_balloc_alloc_block(struct ext4_inode_ref *inode_ref, uint32_t *fblock)
323 uint32_t allocated_block = 0;
324 uint32_t bitmap_block_addr;
325 uint32_t rel_block_idx = 0;
326 uint32_t free_blocks;
328 struct ext4_block bitmap_block;
330 int rc = ext4_balloc_find_goal(inode_ref, &goal);
332 /* no goal found => partition is full */
336 struct ext4_sblock *sb = &inode_ref->fs->sb;
338 /* Load block group number for goal and relative index */
339 uint32_t block_group = ext4_balloc_get_bgid_of_block(sb, goal);
340 uint32_t index_in_group = ext4_fs_baddr2_index_in_group(sb, goal);
342 /* Load block group reference */
343 struct ext4_block_group_ref bg_ref;
344 rc = ext4_fs_get_block_group_ref(inode_ref->fs, block_group, &bg_ref);
348 free_blocks = ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
349 if (free_blocks == 0) {
350 /* This group has no free blocks */
354 /* Compute indexes */
355 uint32_t first_in_group = ext4_balloc_get_block_of_bgid(sb, bg_ref.index);
357 uint32_t first_in_group_index =
358 ext4_fs_baddr2_index_in_group(sb, first_in_group);
360 if (index_in_group < first_in_group_index)
361 index_in_group = first_in_group_index;
363 /* Load block with bitmap */
364 bitmap_block_addr = ext4_bg_get_block_bitmap(bg_ref.block_group, sb);
366 rc = ext4_block_get(inode_ref->fs->bdev, &bitmap_block,
369 ext4_fs_put_block_group_ref(&bg_ref);
373 /* Check if goal is free */
374 if (ext4_bmap_is_bit_clr(bitmap_block.data, index_in_group)) {
375 ext4_bmap_bit_set(bitmap_block.data, index_in_group);
376 bitmap_block.dirty = true;
377 rc = ext4_block_set(inode_ref->fs->bdev, &bitmap_block);
379 ext4_fs_put_block_group_ref(&bg_ref);
383 allocated_block = ext4_fs_index_in_group2_baddr(
384 sb, index_in_group, block_group);
389 uint32_t blocks_in_group = ext4_blocks_in_group_cnt(sb, block_group);
391 uint32_t end_idx = (index_in_group + 63) & ~63;
392 if (end_idx > blocks_in_group)
393 end_idx = blocks_in_group;
395 /* Try to find free block near to goal */
397 for (tmp_idx = index_in_group + 1; tmp_idx < end_idx; ++tmp_idx) {
398 if (ext4_bmap_is_bit_clr(bitmap_block.data, tmp_idx)) {
399 ext4_bmap_bit_set(bitmap_block.data, tmp_idx);
401 bitmap_block.dirty = true;
402 rc = ext4_block_set(inode_ref->fs->bdev, &bitmap_block);
406 allocated_block = ext4_fs_index_in_group2_baddr(
407 sb, tmp_idx, block_group);
413 /* Find free bit in bitmap */
414 rc = ext4_bmap_bit_find_clr(bitmap_block.data, index_in_group,
415 blocks_in_group, &rel_block_idx);
417 ext4_bmap_bit_set(bitmap_block.data, rel_block_idx);
418 bitmap_block.dirty = true;
419 rc = ext4_block_set(inode_ref->fs->bdev, &bitmap_block);
423 allocated_block = ext4_fs_index_in_group2_baddr(
424 sb, rel_block_idx, block_group);
429 /* No free block found yet */
430 rc = ext4_block_set(inode_ref->fs->bdev, &bitmap_block);
432 ext4_fs_put_block_group_ref(&bg_ref);
438 rc = ext4_fs_put_block_group_ref(&bg_ref);
442 /* Try other block groups */
443 uint32_t block_group_count = ext4_block_group_cnt(sb);
445 uint32_t bgid = (block_group + 1) % block_group_count;
446 uint32_t count = block_group_count;
449 rc = ext4_fs_get_block_group_ref(inode_ref->fs, bgid, &bg_ref);
454 ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
455 if (free_blocks == 0) {
456 /* This group has no free blocks */
460 /* Load block with bitmap */
462 ext4_bg_get_block_bitmap(bg_ref.block_group, sb);
464 rc = ext4_block_get(inode_ref->fs->bdev, &bitmap_block,
468 ext4_fs_put_block_group_ref(&bg_ref);
472 /* Compute indexes */
473 first_in_group = ext4_balloc_get_block_of_bgid(sb, bgid);
475 ext4_fs_baddr2_index_in_group(sb, first_in_group);
476 blocks_in_group = ext4_blocks_in_group_cnt(sb, bgid);
478 first_in_group_index =
479 ext4_fs_baddr2_index_in_group(sb, first_in_group);
481 if (index_in_group < first_in_group_index)
482 index_in_group = first_in_group_index;
484 rc = ext4_bmap_bit_find_clr(bitmap_block.data, index_in_group,
485 blocks_in_group, &rel_block_idx);
489 ext4_bmap_bit_set(bitmap_block.data, rel_block_idx);
491 bitmap_block.dirty = true;
492 rc = ext4_block_set(inode_ref->fs->bdev, &bitmap_block);
494 ext4_fs_put_block_group_ref(&bg_ref);
498 allocated_block = ext4_fs_index_in_group2_baddr(
499 sb, rel_block_idx, bgid);
504 rc = ext4_block_set(inode_ref->fs->bdev, &bitmap_block);
506 ext4_fs_put_block_group_ref(&bg_ref);
511 rc = ext4_fs_put_block_group_ref(&bg_ref);
516 /* Goto next group */
517 bgid = (bgid + 1) % block_group_count;
524 /* Empty command - because of syntax */
527 uint32_t block_size = ext4_sb_get_block_size(sb);
529 /* Update superblock free blocks count */
530 uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
532 ext4_sb_set_free_blocks_cnt(sb, sb_free_blocks);
534 /* Update inode blocks (different block size!) count */
535 uint64_t ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode);
536 ino_blocks += block_size / EXT4_INODE_BLOCK_SIZE;
537 ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
538 inode_ref->dirty = true;
540 /* Update block group free blocks count */
541 uint32_t bg_free_blocks =
542 ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
544 ext4_bg_set_free_blocks_count(bg_ref.block_group, sb, bg_free_blocks);
548 rc = ext4_fs_put_block_group_ref(&bg_ref);
550 *fblock = allocated_block;
554 int ext4_balloc_try_alloc_block(struct ext4_inode_ref *inode_ref,
555 uint32_t baddr, bool *free)
559 struct ext4_fs *fs = inode_ref->fs;
560 struct ext4_sblock *sb = &fs->sb;
562 /* Compute indexes */
563 uint32_t block_group = ext4_balloc_get_bgid_of_block(sb, baddr);
564 uint32_t index_in_group = ext4_fs_baddr2_index_in_group(sb, baddr);
566 /* Load block group reference */
567 struct ext4_block_group_ref bg_ref;
568 rc = ext4_fs_get_block_group_ref(fs, block_group, &bg_ref);
572 /* Load block with bitmap */
573 uint32_t bitmap_block_addr =
574 ext4_bg_get_block_bitmap(bg_ref.block_group, sb);
576 struct ext4_block bitmap_block;
578 rc = ext4_block_get(fs->bdev, &bitmap_block, bitmap_block_addr);
580 ext4_fs_put_block_group_ref(&bg_ref);
584 /* Check if block is free */
585 *free = ext4_bmap_is_bit_clr(bitmap_block.data, index_in_group);
587 /* Allocate block if possible */
589 ext4_bmap_bit_set(bitmap_block.data, index_in_group);
590 bitmap_block.dirty = true;
593 /* Release block with bitmap */
594 rc = ext4_block_set(fs->bdev, &bitmap_block);
596 /* Error in saving bitmap */
597 ext4_fs_put_block_group_ref(&bg_ref);
601 /* If block is not free, return */
605 uint32_t block_size = ext4_sb_get_block_size(sb);
607 /* Update superblock free blocks count */
608 uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
610 ext4_sb_set_free_blocks_cnt(sb, sb_free_blocks);
612 /* Update inode blocks count */
613 uint64_t ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode);
614 ino_blocks += block_size / EXT4_INODE_BLOCK_SIZE;
615 ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
616 inode_ref->dirty = true;
618 /* Update block group free blocks count */
619 uint32_t free_blocks =
620 ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
622 ext4_bg_set_free_blocks_count(bg_ref.block_group, sb, free_blocks);
627 return ext4_fs_put_block_group_ref(&bg_ref);