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_crc32c.h"
46 #include "ext4_block_group.h"
48 #include "ext4_bitmap.h"
49 #include "ext4_inode.h"
51 /**@brief Compute number of block group from block address.
52 * @param sb superblock pointer.
53 * @param baddr Absolute address of block.
54 * @return Block group index
56 uint32_t ext4_balloc_get_bgid_of_block(struct ext4_sblock *s,
59 if (ext4_get32(s, first_data_block) && baddr)
62 return baddr / ext4_get32(s, blocks_per_group);
65 /**@brief Compute the starting block address of a block group
66 * @param sb superblock pointer.
67 * @param bgid block group index
68 * @return Block address
70 uint64_t ext4_balloc_get_block_of_bgid(struct ext4_sblock *s,
74 if (ext4_get32(s, first_data_block))
77 baddr += bgid * ext4_get32(s, blocks_per_group);
81 static uint32_t ext4_balloc_bitmap_csum(struct ext4_sblock *sb,
84 uint32_t checksum = 0;
85 if (ext4_sb_has_feature_read_only(sb,
86 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) {
87 uint32_t blocks_per_group =
88 ext4_get32(sb, blocks_per_group);
90 /* First calculate crc32 checksum against fs uuid */
91 checksum = ext4_crc32c(~0, sb->uuid, sizeof(sb->uuid));
92 /* Then calculate crc32 checksum against block_group_desc */
93 checksum = ext4_crc32c(checksum, bitmap,
94 (blocks_per_group + 7) / 8);
101 * Currently we do not verify the checksum of bitmaps.
104 static void ext4_balloc_set_bitmap_csum(struct ext4_sblock *sb,
105 struct ext4_bgroup *bg,
108 int desc_size = ext4_sb_get_desc_size(sb);
109 uint32_t checksum = ext4_balloc_bitmap_csum(sb, bitmap);
110 uint16_t lo_checksum = to_le16(checksum & 0xFFFF),
111 hi_checksum = to_le16(checksum >> 16);
113 /* See if we need to assign a 32bit checksum */
114 bg->block_bitmap_csum_lo = lo_checksum;
115 if (desc_size == EXT4_MAX_BLOCK_GROUP_DESCRIPTOR_SIZE)
116 bg->block_bitmap_csum_hi = hi_checksum;
120 int ext4_balloc_free_block(struct ext4_inode_ref *inode_ref, ext4_fsblk_t baddr)
122 struct ext4_fs *fs = inode_ref->fs;
123 struct ext4_sblock *sb = &fs->sb;
125 uint32_t block_group = ext4_balloc_get_bgid_of_block(sb, baddr);
126 uint32_t index_in_group = ext4_fs_baddr2_index_in_group(sb, baddr);
128 /* Load block group reference */
129 struct ext4_block_group_ref bg_ref;
130 int rc = ext4_fs_get_block_group_ref(fs, block_group, &bg_ref);
134 /* Load block with bitmap */
135 ext4_fsblk_t bitmap_block_addr =
136 ext4_bg_get_block_bitmap(bg_ref.block_group, sb);
138 struct ext4_block bitmap_block;
140 rc = ext4_block_get(fs->bdev, &bitmap_block, bitmap_block_addr);
142 ext4_fs_put_block_group_ref(&bg_ref);
147 ext4_bmap_bit_clr(bitmap_block.data, index_in_group);
148 ext4_balloc_set_bitmap_csum(sb, bg_ref.block_group,
150 bitmap_block.dirty = true;
152 /* Release block with bitmap */
153 rc = ext4_block_set(fs->bdev, &bitmap_block);
155 /* Error in saving bitmap */
156 ext4_fs_put_block_group_ref(&bg_ref);
160 uint32_t block_size = ext4_sb_get_block_size(sb);
162 /* Update superblock free blocks count */
163 uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
165 ext4_sb_set_free_blocks_cnt(sb, sb_free_blocks);
167 /* Update inode blocks count */
168 uint64_t ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode);
169 ino_blocks -= block_size / EXT4_INODE_BLOCK_SIZE;
170 ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
171 inode_ref->dirty = true;
173 /* Update block group free blocks count */
174 uint32_t free_blocks =
175 ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
177 ext4_bg_set_free_blocks_count(bg_ref.block_group, sb, free_blocks);
181 /* Release block group reference */
182 return ext4_fs_put_block_group_ref(&bg_ref);
185 int ext4_balloc_free_blocks(struct ext4_inode_ref *inode_ref, ext4_fsblk_t first,
189 struct ext4_fs *fs = inode_ref->fs;
190 struct ext4_sblock *sb = &fs->sb;
192 /* Compute indexes */
193 uint32_t block_group_first = ext4_balloc_get_bgid_of_block(sb, first);
195 /* Compute indexes */
196 uint32_t block_group_last =
197 ext4_balloc_get_bgid_of_block(sb, first + count - 1);
199 if (!ext4_sb_has_feature_incompatible(sb,
200 EXT4_FEATURE_INCOMPAT_FLEX_BG)) {
201 /*It is not possible without flex_bg that blocks are continuous
202 * and and last block belongs to other bg.*/
203 ext4_assert(block_group_first == ext4_balloc_get_bgid_of_block(
204 sb, first + count - 1));
207 /* Load block group reference */
208 struct ext4_block_group_ref bg_ref;
209 while (block_group_first <= block_group_last) {
212 ext4_fs_get_block_group_ref(fs, block_group_first, &bg_ref);
216 uint32_t index_in_group_first =
217 ext4_fs_baddr2_index_in_group(sb, first);
219 /* Load block with bitmap */
220 ext4_fsblk_t bitmap_block_addr =
221 ext4_bg_get_block_bitmap(bg_ref.block_group, sb);
223 struct ext4_block bitmap_block;
225 rc = ext4_block_get(fs->bdev, &bitmap_block, bitmap_block_addr);
227 ext4_fs_put_block_group_ref(&bg_ref);
232 ext4_sb_get_block_size(sb) * 8 - index_in_group_first;
234 /*If last block, free only count blocks*/
235 free_cnt = count > free_cnt ? free_cnt : count;
238 ext4_bmap_bits_free(bitmap_block.data, index_in_group_first,
240 ext4_balloc_set_bitmap_csum(sb, bg_ref.block_group,
242 bitmap_block.dirty = true;
247 /* Release block with bitmap */
248 rc = ext4_block_set(fs->bdev, &bitmap_block);
250 ext4_fs_put_block_group_ref(&bg_ref);
254 uint32_t block_size = ext4_sb_get_block_size(sb);
256 /* Update superblock free blocks count */
257 uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
258 sb_free_blocks += free_cnt;
259 ext4_sb_set_free_blocks_cnt(sb, sb_free_blocks);
261 /* Update inode blocks count */
262 uint64_t ino_blocks =
263 ext4_inode_get_blocks_count(sb, inode_ref->inode);
264 ino_blocks -= free_cnt * (block_size / EXT4_INODE_BLOCK_SIZE);
265 ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
266 inode_ref->dirty = true;
268 /* Update block group free blocks count */
269 uint32_t free_blocks =
270 ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
271 free_blocks += free_cnt;
272 ext4_bg_set_free_blocks_count(bg_ref.block_group, sb,
276 /* Release block group reference */
277 rc = ext4_fs_put_block_group_ref(&bg_ref);
284 /*All blocks should be released*/
285 ext4_assert(count == 0);
289 int ext4_balloc_alloc_block(struct ext4_inode_ref *inode_ref,
291 ext4_fsblk_t *fblock)
293 ext4_fsblk_t allocated_block = 0;
294 ext4_fsblk_t bitmap_block_addr;
295 uint32_t rel_block_idx = 0;
296 uint64_t free_blocks;
297 struct ext4_block bitmap_block;
300 struct ext4_sblock *sb = &inode_ref->fs->sb;
302 /* Load block group number for goal and relative index */
303 uint32_t block_group = ext4_balloc_get_bgid_of_block(sb, goal);
304 uint32_t index_in_group = ext4_fs_baddr2_index_in_group(sb, goal);
306 /* Load block group reference */
307 struct ext4_block_group_ref bg_ref;
308 rc = ext4_fs_get_block_group_ref(inode_ref->fs, block_group, &bg_ref);
312 free_blocks = ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
313 if (free_blocks == 0) {
314 /* This group has no free blocks */
318 /* Compute indexes */
319 ext4_fsblk_t first_in_group = ext4_balloc_get_block_of_bgid(sb, bg_ref.index);
321 uint32_t first_in_group_index =
322 ext4_fs_baddr2_index_in_group(sb, first_in_group);
324 if (index_in_group < first_in_group_index)
325 index_in_group = first_in_group_index;
327 /* Load block with bitmap */
328 bitmap_block_addr = ext4_bg_get_block_bitmap(bg_ref.block_group, sb);
330 rc = ext4_block_get(inode_ref->fs->bdev, &bitmap_block,
333 ext4_fs_put_block_group_ref(&bg_ref);
337 /* Check if goal is free */
338 if (ext4_bmap_is_bit_clr(bitmap_block.data, index_in_group)) {
339 ext4_bmap_bit_set(bitmap_block.data, index_in_group);
340 ext4_balloc_set_bitmap_csum(sb, bg_ref.block_group,
342 bitmap_block.dirty = true;
343 rc = ext4_block_set(inode_ref->fs->bdev, &bitmap_block);
345 ext4_fs_put_block_group_ref(&bg_ref);
349 allocated_block = ext4_fs_index_in_group2_baddr(
350 sb, index_in_group, block_group);
355 uint32_t blocks_in_group = ext4_blocks_in_group_cnt(sb, block_group);
357 uint32_t end_idx = (index_in_group + 63) & ~63;
358 if (end_idx > blocks_in_group)
359 end_idx = blocks_in_group;
361 /* Try to find free block near to goal */
363 for (tmp_idx = index_in_group + 1; tmp_idx < end_idx; ++tmp_idx) {
364 if (ext4_bmap_is_bit_clr(bitmap_block.data, tmp_idx)) {
365 ext4_bmap_bit_set(bitmap_block.data, tmp_idx);
367 ext4_balloc_set_bitmap_csum(sb, bg_ref.block_group,
369 bitmap_block.dirty = true;
370 rc = ext4_block_set(inode_ref->fs->bdev, &bitmap_block);
374 allocated_block = ext4_fs_index_in_group2_baddr(
375 sb, tmp_idx, block_group);
381 /* Find free bit in bitmap */
382 rc = ext4_bmap_bit_find_clr(bitmap_block.data, index_in_group,
383 blocks_in_group, &rel_block_idx);
385 ext4_bmap_bit_set(bitmap_block.data, rel_block_idx);
386 ext4_balloc_set_bitmap_csum(sb, bg_ref.block_group,
388 bitmap_block.dirty = true;
389 rc = ext4_block_set(inode_ref->fs->bdev, &bitmap_block);
393 allocated_block = ext4_fs_index_in_group2_baddr(
394 sb, rel_block_idx, block_group);
399 /* No free block found yet */
400 rc = ext4_block_set(inode_ref->fs->bdev, &bitmap_block);
402 ext4_fs_put_block_group_ref(&bg_ref);
408 rc = ext4_fs_put_block_group_ref(&bg_ref);
412 /* Try other block groups */
413 uint32_t block_group_count = ext4_block_group_cnt(sb);
415 uint32_t bgid = (block_group + 1) % block_group_count;
416 uint32_t count = block_group_count;
419 rc = ext4_fs_get_block_group_ref(inode_ref->fs, bgid, &bg_ref);
424 ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
425 if (free_blocks == 0) {
426 /* This group has no free blocks */
430 /* Load block with bitmap */
432 ext4_bg_get_block_bitmap(bg_ref.block_group, sb);
434 rc = ext4_block_get(inode_ref->fs->bdev, &bitmap_block,
438 ext4_fs_put_block_group_ref(&bg_ref);
442 /* Compute indexes */
443 first_in_group = ext4_balloc_get_block_of_bgid(sb, bgid);
445 ext4_fs_baddr2_index_in_group(sb, first_in_group);
446 blocks_in_group = ext4_blocks_in_group_cnt(sb, bgid);
448 first_in_group_index =
449 ext4_fs_baddr2_index_in_group(sb, first_in_group);
451 if (index_in_group < first_in_group_index)
452 index_in_group = first_in_group_index;
454 rc = ext4_bmap_bit_find_clr(bitmap_block.data, index_in_group,
455 blocks_in_group, &rel_block_idx);
459 ext4_bmap_bit_set(bitmap_block.data, rel_block_idx);
461 ext4_balloc_set_bitmap_csum(sb, bg_ref.block_group,
463 bitmap_block.dirty = true;
464 rc = ext4_block_set(inode_ref->fs->bdev, &bitmap_block);
466 ext4_fs_put_block_group_ref(&bg_ref);
470 allocated_block = ext4_fs_index_in_group2_baddr(
471 sb, rel_block_idx, bgid);
476 rc = ext4_block_set(inode_ref->fs->bdev, &bitmap_block);
478 ext4_fs_put_block_group_ref(&bg_ref);
483 rc = ext4_fs_put_block_group_ref(&bg_ref);
488 /* Goto next group */
489 bgid = (bgid + 1) % block_group_count;
496 /* Empty command - because of syntax */
499 uint32_t block_size = ext4_sb_get_block_size(sb);
501 /* Update superblock free blocks count */
502 uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
504 ext4_sb_set_free_blocks_cnt(sb, sb_free_blocks);
506 /* Update inode blocks (different block size!) count */
507 uint64_t ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode);
508 ino_blocks += block_size / EXT4_INODE_BLOCK_SIZE;
509 ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
510 inode_ref->dirty = true;
512 /* Update block group free blocks count */
513 uint64_t bg_free_blocks =
514 ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
516 ext4_bg_set_free_blocks_count(bg_ref.block_group, sb, bg_free_blocks);
520 rc = ext4_fs_put_block_group_ref(&bg_ref);
522 *fblock = allocated_block;
526 int ext4_balloc_try_alloc_block(struct ext4_inode_ref *inode_ref,
527 ext4_fsblk_t baddr, bool *free)
531 struct ext4_fs *fs = inode_ref->fs;
532 struct ext4_sblock *sb = &fs->sb;
534 /* Compute indexes */
535 uint32_t block_group = ext4_balloc_get_bgid_of_block(sb, baddr);
536 uint32_t index_in_group = ext4_fs_baddr2_index_in_group(sb, baddr);
538 /* Load block group reference */
539 struct ext4_block_group_ref bg_ref;
540 rc = ext4_fs_get_block_group_ref(fs, block_group, &bg_ref);
544 /* Load block with bitmap */
545 ext4_fsblk_t bitmap_block_addr =
546 ext4_bg_get_block_bitmap(bg_ref.block_group, sb);
548 struct ext4_block bitmap_block;
550 rc = ext4_block_get(fs->bdev, &bitmap_block, bitmap_block_addr);
552 ext4_fs_put_block_group_ref(&bg_ref);
556 /* Check if block is free */
557 *free = ext4_bmap_is_bit_clr(bitmap_block.data, index_in_group);
559 /* Allocate block if possible */
561 ext4_bmap_bit_set(bitmap_block.data, index_in_group);
562 ext4_balloc_set_bitmap_csum(sb, bg_ref.block_group,
564 bitmap_block.dirty = true;
567 /* Release block with bitmap */
568 rc = ext4_block_set(fs->bdev, &bitmap_block);
570 /* Error in saving bitmap */
571 ext4_fs_put_block_group_ref(&bg_ref);
575 /* If block is not free, return */
579 uint32_t block_size = ext4_sb_get_block_size(sb);
581 /* Update superblock free blocks count */
582 uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
584 ext4_sb_set_free_blocks_cnt(sb, sb_free_blocks);
586 /* Update inode blocks count */
587 uint64_t ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode);
588 ino_blocks += block_size / EXT4_INODE_BLOCK_SIZE;
589 ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
590 inode_ref->dirty = true;
592 /* Update block group free blocks count */
593 uint32_t free_blocks =
594 ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
596 ext4_bg_set_free_blocks_count(bg_ref.block_group, sb, free_blocks);
601 return ext4_fs_put_block_group_ref(&bg_ref);