source: mainline/uspace/lib/ext4/libext4_balloc.c@ d510ac01

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since d510ac01 was 06d85e5, checked in by Frantisek Princ <frantisek.princ@…>, 13 years ago

Most of comments modified by current coding style
  • Property mode set to 100644
File size: 20.8 KB
Line 
1/*
2 * Copyright (c) 2012 Frantisek Princ
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * - Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * - Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * - The name of the author may not be used to endorse or promote products
15 * derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29/** @addtogroup libext4
30 * @{
31 */
32
33/**
34 * @file libext4_balloc.c
35 * @brief Physical block allocator.
36 */
37
38#include <errno.h>
39#include <sys/types.h>
40#include "libext4.h"
41
42/** Convert block address to relative index in block group.
43 *
44 * @param sb superblock pointer
45 * @param block_addr block number to convert
46 * @return relative number of block
47 */
48static uint32_t ext4_balloc_blockaddr2_index_in_group(ext4_superblock_t *sb,
49 uint32_t block_addr)
50{
51 uint32_t blocks_per_group = ext4_superblock_get_blocks_per_group(sb);
52 uint32_t first_block = ext4_superblock_get_first_data_block(sb);
53
54 /* First block == 0 or 1 */
55 if (first_block == 0) {
56 return block_addr % blocks_per_group;
57 } else {
58 return (block_addr - 1) % blocks_per_group;
59 }
60}
61
62/** Convert relative block number to absolute.
63 *
64 * @param sb superblock pointer
65 * @param index relative index of block in group
66 * @param bgid index of block group
67 * @return absolute number of block
68 */
69static uint32_t ext4_balloc_index_in_group2blockaddr(ext4_superblock_t *sb,
70 uint32_t index, uint32_t bgid)
71{
72 uint32_t blocks_per_group = ext4_superblock_get_blocks_per_group(sb);
73
74 if (ext4_superblock_get_first_data_block(sb) == 0) {
75 return bgid * blocks_per_group + index;
76 } else {
77 return bgid * blocks_per_group + index + 1;
78 }
79
80}
81
82/** Compute number of block group from block address.
83 *
84 * @param sb superblock pointer
85 * @param block_addr absolute address of block
86 * @return block group index
87 */
88static uint32_t ext4_balloc_get_bgid_of_block(ext4_superblock_t *sb,
89 uint32_t block_addr)
90{
91 uint32_t blocks_per_group = ext4_superblock_get_blocks_per_group(sb);
92 uint32_t first_block = ext4_superblock_get_first_data_block(sb);
93
94 /* First block == 0 or 1 */
95 if (first_block == 0) {
96 return block_addr / blocks_per_group;
97 } else {
98 return (block_addr - 1) / blocks_per_group;
99 }
100}
101
102
103/** Free block.
104 *
105 * @param inode_ref inode, where the block is allocated
106 * @param block_addr absolute block address to free
107 * @return error code
108 */
109int ext4_balloc_free_block(ext4_inode_ref_t *inode_ref, uint32_t block_addr)
110{
111 int rc;
112
113 ext4_filesystem_t *fs = inode_ref->fs;
114 ext4_superblock_t *sb = fs->superblock;
115
116 /* Compute indexes */
117 uint32_t block_group = ext4_balloc_get_bgid_of_block(sb, block_addr);
118 uint32_t index_in_group = ext4_balloc_blockaddr2_index_in_group(sb, block_addr);
119
120 /* Load block group reference */
121 ext4_block_group_ref_t *bg_ref;
122 rc = ext4_filesystem_get_block_group_ref(fs, block_group, &bg_ref);
123 if (rc != EOK) {
124 EXT4FS_DBG("error in loading bg_ref \%d", rc);
125 return rc;
126 }
127
128 /* Load block with bitmap */
129 uint32_t bitmap_block_addr = ext4_block_group_get_block_bitmap(
130 bg_ref->block_group, sb);
131 block_t *bitmap_block;
132 rc = block_get(&bitmap_block, fs->device, bitmap_block_addr, 0);
133 if (rc != EOK) {
134 EXT4FS_DBG("error in loading bitmap \%d", rc);
135 return rc;
136 }
137
138 /* Modify bitmap */
139 ext4_bitmap_free_bit(bitmap_block->data, index_in_group);
140 bitmap_block->dirty = true;
141
142
143 /* Release block with bitmap */
144 rc = block_put(bitmap_block);
145 if (rc != EOK) {
146 /* Error in saving bitmap */
147 ext4_filesystem_put_block_group_ref(bg_ref);
148 EXT4FS_DBG("error in saving bitmap \%d", rc);
149 return rc;
150 }
151
152 uint32_t block_size = ext4_superblock_get_block_size(sb);
153
154 /* Update superblock free blocks count */
155 uint32_t sb_free_blocks = ext4_superblock_get_free_blocks_count(sb);
156 sb_free_blocks++;
157 ext4_superblock_set_free_blocks_count(sb, sb_free_blocks);
158
159 /* Update inode blocks count */
160 uint64_t ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode);
161 ino_blocks -= block_size / EXT4_INODE_BLOCK_SIZE;
162 ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
163 inode_ref->dirty = true;
164
165 /* Update block group free blocks count */
166 uint32_t free_blocks = ext4_block_group_get_free_blocks_count(
167 bg_ref->block_group, sb);
168 free_blocks++;
169 ext4_block_group_set_free_blocks_count(bg_ref->block_group,
170 sb, free_blocks);
171 bg_ref->dirty = true;
172
173 /* Release block group reference */
174 rc = ext4_filesystem_put_block_group_ref(bg_ref);
175 if (rc != EOK) {
176 EXT4FS_DBG("error in saving bg_ref \%d", rc);
177 return rc;
178 }
179
180 return EOK;
181}
182
183
184/** Free continuous set of blocks.
185 *
186 * @param inode_ref inode, where the blocks are allocated
187 * @param first first block to release
188 * @param count number of blocks to release
189 */
190int ext4_balloc_free_blocks(ext4_inode_ref_t *inode_ref,
191 uint32_t first, uint32_t count)
192{
193 int rc;
194
195 ext4_filesystem_t *fs = inode_ref->fs;
196 ext4_superblock_t *sb = fs->superblock;
197
198 /* Compute indexes */
199 uint32_t block_group_first =
200 ext4_balloc_get_bgid_of_block(sb, first);
201 uint32_t block_group_last =
202 ext4_balloc_get_bgid_of_block(sb, first + count - 1);
203
204 assert(block_group_first == block_group_last);
205
206 /* Load block group reference */
207 ext4_block_group_ref_t *bg_ref;
208 rc = ext4_filesystem_get_block_group_ref(fs, block_group_first, &bg_ref);
209 if (rc != EOK) {
210 EXT4FS_DBG("error in loading bg_ref \%d", rc);
211 return rc;
212 }
213
214 uint32_t index_in_group_first =
215 ext4_balloc_blockaddr2_index_in_group(sb, first);
216
217
218 /* Load block with bitmap */
219 uint32_t bitmap_block_addr = ext4_block_group_get_block_bitmap(
220 bg_ref->block_group, sb);
221
222 block_t *bitmap_block;
223 rc = block_get(&bitmap_block, fs->device, bitmap_block_addr, 0);
224 if (rc != EOK) {
225 EXT4FS_DBG("error in loading bitmap \%d", rc);
226 return rc;
227 }
228
229 /* Modify bitmap */
230 ext4_bitmap_free_bits(bitmap_block->data, index_in_group_first, count);
231 bitmap_block->dirty = true;
232
233 /* Release block with bitmap */
234 rc = block_put(bitmap_block);
235 if (rc != EOK) {
236 /* Error in saving bitmap */
237 ext4_filesystem_put_block_group_ref(bg_ref);
238 EXT4FS_DBG("error in saving bitmap \%d", rc);
239 return rc;
240 }
241
242 uint32_t block_size = ext4_superblock_get_block_size(sb);
243
244 /* Update superblock free blocks count */
245 uint32_t sb_free_blocks = ext4_superblock_get_free_blocks_count(sb);
246 sb_free_blocks += count;
247 ext4_superblock_set_free_blocks_count(sb, sb_free_blocks);
248
249 /* Update inode blocks count */
250 uint64_t ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode);
251 ino_blocks -= count * (block_size / EXT4_INODE_BLOCK_SIZE);
252 ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
253 inode_ref->dirty = true;
254
255 /* Update block group free blocks count */
256 uint32_t free_blocks = ext4_block_group_get_free_blocks_count(
257 bg_ref->block_group, sb);
258 free_blocks += count;
259 ext4_block_group_set_free_blocks_count(bg_ref->block_group,
260 sb, free_blocks);
261 bg_ref->dirty = true;
262
263 /* Release block group reference */
264 rc = ext4_filesystem_put_block_group_ref(bg_ref);
265 if (rc != EOK) {
266 EXT4FS_DBG("error in saving bg_ref \%d", rc);
267 return rc;
268 }
269
270 return EOK;
271}
272
273/** Compute first block for data in block group.
274 *
275 * @param sb pointer to superblock
276 * @param bg pointer to block group
277 * @param bgid index of block group
278 * @return absolute block index of first block
279 */
280static uint32_t ext4_balloc_get_first_data_block_in_group(
281 ext4_superblock_t *sb, ext4_block_group_t *bg, uint32_t bgid)
282{
283 uint32_t block_group_count = ext4_superblock_get_block_group_count(sb);
284 uint32_t inode_table_first_block = ext4_block_group_get_inode_table_first_block(
285 bg, sb);
286 uint16_t inode_table_item_size = ext4_superblock_get_inode_size(sb);
287 uint32_t inodes_per_group = ext4_superblock_get_inodes_per_group(sb);
288 uint32_t block_size = ext4_superblock_get_block_size(sb);
289 uint32_t inode_table_bytes;
290
291 if (bgid < block_group_count - 1) {
292 inode_table_bytes = inodes_per_group * inode_table_item_size;
293 } else {
294 /* last block group could be smaller */
295 uint32_t inodes_count_total = ext4_superblock_get_inodes_count(sb);
296 inode_table_bytes =
297 (inodes_count_total - ((block_group_count - 1) * inodes_per_group))
298 * inode_table_item_size;
299 }
300
301 uint32_t inode_table_blocks = inode_table_bytes / block_size;
302
303 if (inode_table_bytes % block_size) {
304 inode_table_blocks++;
305 }
306
307 return inode_table_first_block + inode_table_blocks;
308}
309
310/** Compute 'goal' for allocation algorithm.
311 *
312 * @param inode_ref reference to inode, to allocate block for
313 * @return goal block number
314 */
315static uint32_t ext4_balloc_find_goal(ext4_inode_ref_t *inode_ref)
316{
317 int rc;
318 uint32_t goal = 0;
319
320 ext4_superblock_t *sb = inode_ref->fs->superblock;
321
322 uint64_t inode_size = ext4_inode_get_size(sb, inode_ref->inode);
323 uint32_t block_size = ext4_superblock_get_block_size(sb);
324 uint32_t inode_block_count = inode_size / block_size;
325
326 if (inode_size % block_size != 0) {
327 inode_block_count++;
328 }
329
330 /* If inode has some blocks, get last block address + 1 */
331 if (inode_block_count > 0) {
332
333 rc = ext4_filesystem_get_inode_data_block_index(inode_ref, inode_block_count - 1, &goal);
334 if (rc != EOK) {
335 return 0;
336 }
337
338 if (goal != 0) {
339 goal++;
340 return goal;
341 }
342
343 /* if goal == 0, sparse file -> continue */
344 }
345
346 /* Identify block group of inode */
347 uint32_t inodes_per_group = ext4_superblock_get_inodes_per_group(sb);
348 uint32_t block_group = (inode_ref->index - 1) / inodes_per_group;
349 block_size = ext4_superblock_get_block_size(sb);
350
351 /* Load block group reference */
352 ext4_block_group_ref_t *bg_ref;
353 rc = ext4_filesystem_get_block_group_ref(inode_ref->fs, block_group, &bg_ref);
354 if (rc != EOK) {
355 return 0;
356 }
357
358 /* Compute indexes */
359 uint32_t block_group_count = ext4_superblock_get_block_group_count(sb);
360 uint32_t inode_table_first_block = ext4_block_group_get_inode_table_first_block(
361 bg_ref->block_group, sb);
362 uint16_t inode_table_item_size = ext4_superblock_get_inode_size(sb);
363 uint32_t inode_table_bytes;
364
365 /* Check for last block group */
366 if (block_group < block_group_count - 1) {
367 inode_table_bytes = inodes_per_group * inode_table_item_size;
368 } else {
369 /* last block group could be smaller */
370 uint32_t inodes_count_total = ext4_superblock_get_inodes_count(sb);
371 inode_table_bytes =
372 (inodes_count_total - ((block_group_count - 1) * inodes_per_group))
373 * inode_table_item_size;
374 }
375
376 uint32_t inode_table_blocks = inode_table_bytes / block_size;
377
378 if (inode_table_bytes % block_size) {
379 inode_table_blocks++;
380 }
381
382 goal = inode_table_first_block + inode_table_blocks;
383
384 ext4_filesystem_put_block_group_ref(bg_ref);
385
386 return goal;
387}
388
389/** Data block allocation algorithm.
390 *
391 * @param inode_ref inode to allocate block for
392 * @param fblock allocated block address
393 * @return error code
394 */
395int ext4_balloc_alloc_block(
396 ext4_inode_ref_t *inode_ref, uint32_t *fblock)
397{
398 int rc;
399 uint32_t allocated_block = 0;
400
401 uint32_t bitmap_block_addr;
402 block_t *bitmap_block;
403 uint32_t rel_block_idx = 0;
404
405 /* Find GOAL */
406 uint32_t goal = ext4_balloc_find_goal(inode_ref);
407 if (goal == 0) {
408 /* no goal found => partition is full */
409 EXT4FS_DBG("ERROR (goal == 0)");
410 return ENOSPC;
411 }
412
413 ext4_superblock_t *sb = inode_ref->fs->superblock;
414
415 /* Load block group number for goal and relative index */
416 uint32_t block_group = ext4_balloc_get_bgid_of_block(sb, goal);
417 uint32_t index_in_group = ext4_balloc_blockaddr2_index_in_group(sb, goal);
418
419
420 /* Load block group reference */
421 ext4_block_group_ref_t *bg_ref;
422 rc = ext4_filesystem_get_block_group_ref(inode_ref->fs, block_group, &bg_ref);
423 if (rc != EOK) {
424 EXT4FS_DBG("initial BG ref not loaded");
425 return rc;
426 }
427
428 /* Compute indexes */
429 uint32_t first_in_group =
430 ext4_balloc_get_first_data_block_in_group(sb,
431 bg_ref->block_group, block_group);
432
433 uint32_t first_in_group_index = ext4_balloc_blockaddr2_index_in_group(
434 sb, first_in_group);
435
436 if (index_in_group < first_in_group_index) {
437 index_in_group = first_in_group_index;
438 }
439
440 /* Load block with bitmap */
441 bitmap_block_addr = ext4_block_group_get_block_bitmap(bg_ref->block_group,
442 sb);
443
444 rc = block_get(&bitmap_block, inode_ref->fs->device, bitmap_block_addr, 0);
445 if (rc != EOK) {
446 ext4_filesystem_put_block_group_ref(bg_ref);
447 EXT4FS_DBG("initial bitmap not loaded");
448 return rc;
449 }
450
451 /* Check if goal is free */
452 if (ext4_bitmap_is_free_bit(bitmap_block->data, index_in_group)) {
453 ext4_bitmap_set_bit(bitmap_block->data, index_in_group);
454 bitmap_block->dirty = true;
455 rc = block_put(bitmap_block);
456 if (rc != EOK) {
457 EXT4FS_DBG("goal check: error in saving bitmap \%d", rc);
458 ext4_filesystem_put_block_group_ref(bg_ref);
459 return rc;
460 }
461
462 allocated_block = goal;
463 goto success;
464
465 }
466
467 uint32_t blocks_in_group = ext4_superblock_get_blocks_in_group(sb, block_group);
468
469 uint32_t end_idx = (index_in_group + 63) & ~63;
470 if (end_idx > blocks_in_group) {
471 end_idx = blocks_in_group;
472 }
473
474 /* Try to find free block near to goal */
475 for (uint32_t tmp_idx = index_in_group + 1; tmp_idx < end_idx; ++tmp_idx) {
476 if (ext4_bitmap_is_free_bit(bitmap_block->data, tmp_idx)) {
477
478 ext4_bitmap_set_bit(bitmap_block->data, tmp_idx);
479 bitmap_block->dirty = true;
480 rc = block_put(bitmap_block);
481 if (rc != EOK) {
482 EXT4FS_DBG("near blocks: error in saving initial bitmap \%d", rc);
483 return rc;
484 }
485
486 allocated_block = ext4_balloc_index_in_group2blockaddr(
487 sb, tmp_idx, block_group);
488
489 goto success;
490 }
491
492 }
493
494 /* Find free BYTE in bitmap */
495 rc = ext4_bitmap_find_free_byte_and_set_bit(bitmap_block->data, index_in_group, &rel_block_idx, blocks_in_group);
496 if (rc == EOK) {
497 bitmap_block->dirty = true;
498 rc = block_put(bitmap_block);
499 if (rc != EOK) {
500 EXT4FS_DBG("free byte: error in saving initial bitmap \%d", rc);
501 return rc;
502 }
503
504 allocated_block = ext4_balloc_index_in_group2blockaddr(
505 sb, rel_block_idx, block_group);
506
507 goto success;
508 }
509
510 /* Find free bit in bitmap */
511 rc = ext4_bitmap_find_free_bit_and_set(bitmap_block->data, index_in_group, &rel_block_idx, blocks_in_group);
512 if (rc == EOK) {
513 bitmap_block->dirty = true;
514 rc = block_put(bitmap_block);
515 if (rc != EOK) {
516 EXT4FS_DBG("free bit: error in saving initial bitmap \%d", rc);
517 return rc;
518 }
519
520 allocated_block = ext4_balloc_index_in_group2blockaddr(
521 sb, rel_block_idx, block_group);
522
523 goto success;
524 }
525
526 /* No free block found yet */
527 block_put(bitmap_block);
528 ext4_filesystem_put_block_group_ref(bg_ref);
529
530 /* Try other block groups */
531 uint32_t block_group_count = ext4_superblock_get_block_group_count(sb);
532
533 uint32_t bgid = (block_group + 1) % block_group_count;
534 uint32_t count = block_group_count;
535
536 while (count > 0) {
537 rc = ext4_filesystem_get_block_group_ref(inode_ref->fs, bgid, &bg_ref);
538 if (rc != EOK) {
539 EXT4FS_DBG("ERROR: unable to load block group \%u", bgid);
540 return rc;
541 }
542
543 /* Load block with bitmap */
544 bitmap_block_addr = ext4_block_group_get_block_bitmap(
545 bg_ref->block_group, sb);
546
547 rc = block_get(&bitmap_block, inode_ref->fs->device, bitmap_block_addr, 0);
548 if (rc != EOK) {
549 ext4_filesystem_put_block_group_ref(bg_ref);
550 EXT4FS_DBG("ERROR: unable to load bitmap block");
551 return rc;
552 }
553
554 /* Compute indexes */
555 first_in_group = ext4_balloc_get_first_data_block_in_group(
556 sb, bg_ref->block_group, bgid);
557 index_in_group = ext4_balloc_blockaddr2_index_in_group(sb,
558 first_in_group);
559 blocks_in_group = ext4_superblock_get_blocks_in_group(sb, bgid);
560
561 first_in_group_index = ext4_balloc_blockaddr2_index_in_group(
562 sb, first_in_group);
563
564 if (index_in_group < first_in_group_index) {
565 index_in_group = first_in_group_index;
566 }
567
568 /* Try to find free byte in bitmap */
569 rc = ext4_bitmap_find_free_byte_and_set_bit(bitmap_block->data, index_in_group, &rel_block_idx, blocks_in_group);
570 if (rc == EOK) {
571 bitmap_block->dirty = true;
572 rc = block_put(bitmap_block);
573 if (rc != EOK) {
574 EXT4FS_DBG("ERROR: unable to save bitmap block");
575 return rc;
576 }
577
578 allocated_block = ext4_balloc_index_in_group2blockaddr(
579 sb, rel_block_idx, bgid);
580
581 goto success;
582 }
583
584 /* Try to find free bit in bitmap */
585 rc = ext4_bitmap_find_free_bit_and_set(bitmap_block->data, index_in_group, &rel_block_idx, blocks_in_group);
586 if (rc == EOK) {
587 bitmap_block->dirty = true;
588 rc = block_put(bitmap_block);
589 if (rc != EOK) {
590 EXT4FS_DBG("ERROR: unable to save bitmap block");
591 return rc;
592 }
593
594 allocated_block = ext4_balloc_index_in_group2blockaddr(
595 sb, rel_block_idx, bgid);
596
597 goto success;
598 }
599
600 block_put(bitmap_block);
601 ext4_filesystem_put_block_group_ref(bg_ref);
602
603 /* Goto next group */
604 bgid = (bgid + 1) % block_group_count;
605 count--;
606 }
607
608 return ENOSPC;
609
610success:
611 ; /* Empty command - because of syntax */
612
613 uint32_t block_size = ext4_superblock_get_block_size(sb);
614
615 /* Update superblock free blocks count */
616 uint32_t sb_free_blocks = ext4_superblock_get_free_blocks_count(sb);
617 sb_free_blocks--;
618 ext4_superblock_set_free_blocks_count(sb, sb_free_blocks);
619
620 /* Update inode blocks (different block size!) count */
621 uint64_t ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode);
622 ino_blocks += block_size / EXT4_INODE_BLOCK_SIZE;
623 ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
624 inode_ref->dirty = true;
625
626 /* Update block group free blocks count */
627 uint32_t bg_free_blocks = ext4_block_group_get_free_blocks_count(
628 bg_ref->block_group, sb);
629 bg_free_blocks--;
630 ext4_block_group_set_free_blocks_count(bg_ref->block_group, sb, bg_free_blocks);
631 bg_ref->dirty = true;
632
633 ext4_filesystem_put_block_group_ref(bg_ref);
634
635 *fblock = allocated_block;
636 return EOK;
637}
638
639/** Try to allocate concrete block.
640 *
641 * @param inode_ref inode to allocate block for
642 * @param fblock block address to allocate
643 * @param free output value - if target block is free
644 * @return error code
645 */
646int ext4_balloc_try_alloc_block(ext4_inode_ref_t *inode_ref,
647 uint32_t fblock, bool *free)
648{
649 int rc = EOK;
650
651 ext4_filesystem_t *fs = inode_ref->fs;
652 ext4_superblock_t *sb = fs->superblock;
653
654 /* Compute indexes */
655 uint32_t block_group = ext4_balloc_get_bgid_of_block(sb, fblock);
656 uint32_t index_in_group = ext4_balloc_blockaddr2_index_in_group(sb, fblock);
657
658 /* Load block group reference */
659 ext4_block_group_ref_t *bg_ref;
660 rc = ext4_filesystem_get_block_group_ref(fs, block_group, &bg_ref);
661 if (rc != EOK) {
662 EXT4FS_DBG("error in loading bg_ref \%d", rc);
663 return rc;
664 }
665
666 /* Load block with bitmap */
667 uint32_t bitmap_block_addr = ext4_block_group_get_block_bitmap(
668 bg_ref->block_group, sb);
669 block_t *bitmap_block;
670 rc = block_get(&bitmap_block, fs->device, bitmap_block_addr, 0);
671 if (rc != EOK) {
672 EXT4FS_DBG("error in loading bitmap \%d", rc);
673 return rc;
674 }
675
676 /* Check if block is free */
677 *free = ext4_bitmap_is_free_bit(bitmap_block->data, index_in_group);
678
679 /* Allocate block if possible */
680 if (*free) {
681 ext4_bitmap_set_bit(bitmap_block->data, index_in_group);
682 bitmap_block->dirty = true;
683 }
684
685 /* Release block with bitmap */
686 rc = block_put(bitmap_block);
687 if (rc != EOK) {
688 /* Error in saving bitmap */
689 ext4_filesystem_put_block_group_ref(bg_ref);
690 EXT4FS_DBG("error in saving bitmap \%d", rc);
691 return rc;
692 }
693
694 /* If block is not free, return */
695 if (!(*free)) {
696 goto terminate;
697 }
698
699 uint32_t block_size = ext4_superblock_get_block_size(sb);
700
701 /* Update superblock free blocks count */
702 uint32_t sb_free_blocks = ext4_superblock_get_free_blocks_count(sb);
703 sb_free_blocks--;
704 ext4_superblock_set_free_blocks_count(sb, sb_free_blocks);
705
706 /* Update inode blocks count */
707 uint64_t ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode);
708 ino_blocks += block_size / EXT4_INODE_BLOCK_SIZE;
709 ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
710 inode_ref->dirty = true;
711
712 /* Update block group free blocks count */
713 uint32_t free_blocks = ext4_block_group_get_free_blocks_count(
714 bg_ref->block_group, sb);
715 free_blocks--;
716 ext4_block_group_set_free_blocks_count(bg_ref->block_group,
717 sb, free_blocks);
718 bg_ref->dirty = true;
719
720terminate:
721
722 rc = ext4_filesystem_put_block_group_ref(bg_ref);
723 if (rc != EOK) {
724 EXT4FS_DBG("error in saving bg_ref \%d", rc);
725 return rc;
726 }
727
728 return rc;
729}
730
731/**
732 * @}
733 */
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