2 * Copyright (C) 2010 The Android Open Source Project
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
17 #include "ext4_utils.h"
20 #include <sparse/sparse.h>
25 struct xattr_list_element {
26 struct ext4_inode *inode;
27 struct ext4_xattr_header *header;
28 struct xattr_list_element *next;
31 struct block_allocation *create_allocation()
33 struct block_allocation *alloc = malloc(sizeof(struct block_allocation));
34 alloc->list.first = NULL;
35 alloc->list.last = NULL;
36 alloc->oob_list.first = NULL;
37 alloc->oob_list.last = NULL;
38 alloc->list.iter = NULL;
39 alloc->list.partial_iter = 0;
40 alloc->oob_list.iter = NULL;
41 alloc->oob_list.partial_iter = 0;
42 alloc->filename = NULL;
47 static struct ext4_xattr_header *xattr_list_find(struct ext4_inode *inode)
49 struct xattr_list_element *element;
50 for (element = aux_info.xattrs; element != NULL; element = element->next) {
51 if (element->inode == inode)
52 return element->header;
57 static void xattr_list_insert(struct ext4_inode *inode, struct ext4_xattr_header *header)
59 struct xattr_list_element *element = malloc(sizeof(struct xattr_list_element));
60 element->inode = inode;
61 element->header = header;
62 element->next = aux_info.xattrs;
63 aux_info.xattrs = element;
66 static void region_list_remove(struct region_list *list, struct region *reg)
69 reg->prev->next = reg->next;
72 reg->next->prev = reg->prev;
74 if (list->first == reg)
75 list->first = reg->next;
77 if (list->last == reg)
78 list->last = reg->prev;
84 void region_list_append(struct region_list *list, struct region *reg)
86 if (list->first == NULL) {
90 list->partial_iter = 0;
93 list->last->next = reg;
94 reg->prev = list->last;
100 void region_list_merge(struct region_list *list1, struct region_list *list2)
102 if (list1->first == NULL) {
103 list1->first = list2->first;
104 list1->last = list2->last;
105 list1->iter = list2->first;
106 list1->partial_iter = 0;
107 list1->first->prev = NULL;
109 list1->last->next = list2->first;
110 list2->first->prev = list1->last;
111 list1->last = list2->last;
115 static void dump_starting_from(struct region *reg)
117 for (; reg; reg = reg->next) {
118 printf("%p: Blocks %d-%d (%d)\n", reg,
119 reg->block, reg->block + reg->len - 1, reg->len)
123 static void dump_region_lists(struct block_allocation *alloc) {
125 printf("Main list:\n");
126 dump_starting_from(alloc->list.first);
128 printf("OOB list:\n");
129 dump_starting_from(alloc->oob_list.first);
133 void print_blocks(FILE* f, struct block_allocation *alloc, char separator)
137 for (reg = alloc->list.first; reg; reg = reg->next) {
139 fprintf(f, "%d", reg->block);
141 fprintf(f, "%d-%d", reg->block, reg->block + reg->len - 1);
148 void append_region(struct block_allocation *alloc,
149 u32 block, u32 len, int bg_num)
152 reg = malloc(sizeof(struct region));
158 region_list_append(&alloc->list, reg);
161 static void allocate_bg_inode_table(struct block_group_info *bg)
163 if (bg->inode_table != NULL)
166 u32 block = bg->first_block + 2;
168 if (bg->has_superblock)
169 block += aux_info.bg_desc_blocks + info.bg_desc_reserve_blocks + 1;
171 bg->inode_table = calloc(aux_info.inode_table_blocks, info.block_size);
172 if (bg->inode_table == NULL)
173 critical_error_errno("calloc");
175 sparse_file_add_data(ext4_sparse_file, bg->inode_table,
176 aux_info.inode_table_blocks * info.block_size, block);
178 bg->flags &= ~EXT4_BG_INODE_UNINIT;
181 static int bitmap_set_bit(u8 *bitmap, u32 bit)
183 if (bitmap[bit / 8] & 1 << (bit % 8))
186 bitmap[bit / 8] |= 1 << (bit % 8);
190 static int bitmap_set_8_bits(u8 *bitmap, u32 bit)
192 int ret = bitmap[bit / 8];
193 bitmap[bit / 8] = 0xFF;
197 /* Marks a the first num_blocks blocks in a block group as used, and accounts
198 for them in the block group free block info. */
199 static int reserve_blocks(struct block_group_info *bg, u32 bg_num, u32 start, u32 num)
204 for (i = 0; i < num && block % 8 != 0; i++, block++) {
205 if (bitmap_set_bit(bg->block_bitmap, block)) {
206 error("attempted to reserve already reserved block %d in block group %d", block, bg_num);
211 for (; i + 8 <= (num & ~7); i += 8, block += 8) {
212 if (bitmap_set_8_bits(bg->block_bitmap, block)) {
213 error("attempted to reserve already reserved block %d in block group %d", block, bg_num);
218 for (; i < num; i++, block++) {
219 if (bitmap_set_bit(bg->block_bitmap, block)) {
220 error("attempted to reserve already reserved block %d in block group %d", block, bg_num);
225 bg->free_blocks -= num;
230 static void free_blocks(struct block_group_info *bg, u32 block, u32 num_blocks)
233 for (i = 0; i < num_blocks; i++, block--)
234 bg->block_bitmap[block / 8] &= ~(1 << (block % 8));
235 bg->free_blocks += num_blocks;
238 /* Reduces an existing allocation by len blocks by return the last blocks
239 to the free pool in their block group. Assumes that the blocks being
240 returned were the last ones allocated out of the block group */
241 void reduce_allocation(struct block_allocation *alloc, u32 len)
244 struct region *last_reg = alloc->list.last;
245 struct block_group_info *bg = &aux_info.bgs[last_reg->bg];
247 if (last_reg->len > len) {
248 free_blocks(bg, last_reg->block + last_reg->len - bg->first_block - 1, len);
249 last_reg->len -= len;
252 struct region *reg = alloc->list.last->prev;
253 free_blocks(bg, last_reg->block + last_reg->len - bg->first_block - 1, last_reg->len);
254 len -= last_reg->len;
258 alloc->list.first = NULL;
259 alloc->list.last = NULL;
260 alloc->list.iter = NULL;
261 alloc->list.partial_iter = 0;
268 static void init_bg(struct block_group_info *bg, unsigned int i)
270 int header_blocks = 2 + aux_info.inode_table_blocks;
272 bg->has_superblock = ext4_bg_has_super_block(i);
274 if (bg->has_superblock)
275 header_blocks += 1 + aux_info.bg_desc_blocks + info.bg_desc_reserve_blocks;
277 bg->bitmaps = calloc(info.block_size, 2);
278 bg->block_bitmap = bg->bitmaps;
279 bg->inode_bitmap = bg->bitmaps + info.block_size;
281 bg->header_blocks = header_blocks;
282 bg->first_block = aux_info.first_data_block + i * info.blocks_per_group;
284 u32 block = bg->first_block;
285 if (bg->has_superblock)
286 block += 1 + aux_info.bg_desc_blocks + info.bg_desc_reserve_blocks;
287 sparse_file_add_data(ext4_sparse_file, bg->bitmaps, 2 * info.block_size,
290 bg->data_blocks_used = 0;
291 bg->free_blocks = info.blocks_per_group;
292 bg->free_inodes = info.inodes_per_group;
293 bg->first_free_inode = 1;
294 bg->flags = EXT4_BG_INODE_UNINIT;
297 bg->max_chunk_count = 1;
298 bg->chunks = (struct region*) calloc(bg->max_chunk_count, sizeof(struct region));
300 if (reserve_blocks(bg, i, 0, bg->header_blocks) < 0)
301 error("failed to reserve %u blocks in block group %u\n", bg->header_blocks, i);
302 // Add empty starting delimiter chunk
303 reserve_bg_chunk(i, bg->header_blocks, 0);
305 if (bg->first_block + info.blocks_per_group > aux_info.len_blocks) {
306 u32 overrun = bg->first_block + info.blocks_per_group - aux_info.len_blocks;
307 reserve_blocks(bg, i, info.blocks_per_group - overrun, overrun);
308 // Add empty ending delimiter chunk
309 reserve_bg_chunk(i, info.blocks_per_group - overrun, 0);
311 reserve_bg_chunk(i, info.blocks_per_group - 1, 0);
316 void block_allocator_init()
320 aux_info.bgs = calloc(sizeof(struct block_group_info), aux_info.groups);
321 if (aux_info.bgs == NULL)
322 critical_error_errno("calloc");
324 for (i = 0; i < aux_info.groups; i++)
325 init_bg(&aux_info.bgs[i], i);
328 void block_allocator_free()
332 for (i = 0; i < aux_info.groups; i++) {
333 free(aux_info.bgs[i].bitmaps);
334 free(aux_info.bgs[i].inode_table);
339 /* Allocate a single block and return its block number */
343 struct block_allocation *blk_alloc = allocate_blocks(1);
345 return EXT4_ALLOCATE_FAILED;
347 block = blk_alloc->list.first->block;
348 free_alloc(blk_alloc);
352 static struct region *ext4_allocate_best_fit_partial(u32 len)
355 unsigned int found_bg = 0, found_prev_chunk = 0, found_block = 0;
356 u32 found_allocate_len = 0;
357 bool minimize = false;
358 struct block_group_info *bgs = aux_info.bgs;
361 for (i = 0; i < aux_info.groups; i++) {
362 for (j = 1; j < bgs[i].chunk_count; j++) {
363 u32 hole_start, hole_size;
364 hole_start = bgs[i].chunks[j-1].block + bgs[i].chunks[j-1].len;
365 hole_size = bgs[i].chunks[j].block - hole_start;
366 if (hole_size == len) {
367 // Perfect fit i.e. right between 2 chunks no need to keep searching
369 found_prev_chunk = j - 1;
370 found_block = hole_start;
371 found_allocate_len = hole_size;
373 } else if (hole_size > len && (found_allocate_len == 0 || (found_allocate_len > hole_size))) {
375 found_prev_chunk = j - 1;
376 found_block = hole_start;
377 found_allocate_len = hole_size;
379 } else if (!minimize) {
380 if (found_allocate_len < hole_size) {
382 found_prev_chunk = j - 1;
383 found_block = hole_start;
384 found_allocate_len = hole_size;
390 if (found_allocate_len == 0) {
391 error("failed to allocate %u blocks, out of space?", len);
394 if (found_allocate_len > len) found_allocate_len = len;
396 // reclaim allocated space in chunk
397 bgs[found_bg].chunks[found_prev_chunk].len += found_allocate_len;
398 if (reserve_blocks(&bgs[found_bg],
401 found_allocate_len) < 0) {
402 error("failed to reserve %u blocks in block group %u\n", found_allocate_len, found_bg);
405 bgs[found_bg].data_blocks_used += found_allocate_len;
406 reg = malloc(sizeof(struct region));
407 reg->block = found_block + bgs[found_bg].first_block;
408 reg->len = found_allocate_len;
415 static struct region *ext4_allocate_best_fit(u32 len)
417 struct region *first_reg = NULL;
418 struct region *prev_reg = NULL;
422 reg = ext4_allocate_best_fit_partial(len);
426 if (first_reg == NULL)
430 prev_reg->next = reg;
431 reg->prev = prev_reg;
441 /* Allocate len blocks. The blocks may be spread across multiple block groups,
442 and are returned in a linked list of the blocks in each block group. The
443 allocation algorithm is:
444 1. If the remaining allocation is larger than any available contiguous region,
445 allocate the largest contiguous region and loop
446 2. Otherwise, allocate the smallest contiguous region that it fits in
448 struct block_allocation *allocate_blocks(u32 len)
450 struct region *reg = ext4_allocate_best_fit(len);
455 struct block_allocation *alloc = create_allocation();
456 alloc->list.first = reg;
457 while (reg->next != NULL)
459 alloc->list.last = reg;
460 alloc->list.iter = alloc->list.first;
461 alloc->list.partial_iter = 0;
465 /* Returns the number of discontiguous regions used by an allocation */
466 int block_allocation_num_regions(struct block_allocation *alloc)
469 struct region *reg = alloc->list.first;
471 for (i = 0; reg != NULL; reg = reg->next)
477 int block_allocation_len(struct block_allocation *alloc)
480 struct region *reg = alloc->list.first;
482 for (i = 0; reg != NULL; reg = reg->next)
488 /* Returns the block number of the block'th block in an allocation */
489 u32 get_block(struct block_allocation *alloc, u32 block)
491 struct region *reg = alloc->list.iter;
492 block += alloc->list.partial_iter;
494 for (; reg; reg = reg->next) {
495 if (block < reg->len)
496 return reg->block + block;
499 return EXT4_ALLOCATE_FAILED;
502 u32 get_oob_block(struct block_allocation *alloc, u32 block)
504 struct region *reg = alloc->oob_list.iter;
505 block += alloc->oob_list.partial_iter;
507 for (; reg; reg = reg->next) {
508 if (block < reg->len)
509 return reg->block + block;
512 return EXT4_ALLOCATE_FAILED;
515 /* Gets the starting block and length in blocks of the first region
517 void get_region(struct block_allocation *alloc, u32 *block, u32 *len)
519 *block = alloc->list.iter->block;
520 *len = alloc->list.iter->len - alloc->list.partial_iter;
523 /* Move to the next region in an allocation */
524 void get_next_region(struct block_allocation *alloc)
526 alloc->list.iter = alloc->list.iter->next;
527 alloc->list.partial_iter = 0;
530 /* Returns the number of free blocks in a block group */
531 u32 get_free_blocks(u32 bg)
533 return aux_info.bgs[bg].free_blocks;
536 int last_region(struct block_allocation *alloc)
538 return (alloc->list.iter == NULL);
541 void rewind_alloc(struct block_allocation *alloc)
543 alloc->list.iter = alloc->list.first;
544 alloc->list.partial_iter = 0;
547 static struct region *do_split_allocation(struct block_allocation *alloc, u32 len)
549 struct region *reg = alloc->list.iter;
553 while (reg && len >= reg->len) {
558 if (reg == NULL && len > 0)
562 new = malloc(sizeof(struct region));
565 new->block = reg->block + len;
566 new->len = reg->len - len;
567 new->next = reg->next;
573 tmp = alloc->list.iter;
574 alloc->list.iter = new;
581 /* Splits an allocation into two allocations. The returned allocation will
582 point to the first half, and the original allocation ptr will point to the
584 static struct region *split_allocation(struct block_allocation *alloc, u32 len)
586 /* First make sure there is a split at the current ptr */
587 do_split_allocation(alloc, alloc->list.partial_iter);
589 /* Then split off len blocks */
590 struct region *middle = do_split_allocation(alloc, len);
591 alloc->list.partial_iter = 0;
595 /* Reserve the next blocks for oob data (indirect or extent blocks) */
596 int reserve_oob_blocks(struct block_allocation *alloc, int blocks)
598 struct region *oob = split_allocation(alloc, blocks);
604 while (oob && oob != alloc->list.iter) {
606 region_list_remove(&alloc->list, oob);
607 region_list_append(&alloc->oob_list, oob);
614 static int advance_list_ptr(struct region_list *list, int blocks)
616 struct region *reg = list->iter;
618 while (reg != NULL && blocks > 0) {
619 if (reg->len > list->partial_iter + blocks) {
620 list->partial_iter += blocks;
624 blocks -= (reg->len - list->partial_iter);
625 list->partial_iter = 0;
635 /* Move the allocation pointer forward */
636 int advance_blocks(struct block_allocation *alloc, int blocks)
638 return advance_list_ptr(&alloc->list, blocks);
641 int advance_oob_blocks(struct block_allocation *alloc, int blocks)
643 return advance_list_ptr(&alloc->oob_list, blocks);
646 int append_oob_allocation(struct block_allocation *alloc, u32 len)
648 struct region *reg = ext4_allocate_best_fit(len);
651 error("failed to allocate %d blocks", len);
655 for (; reg; reg = reg->next)
656 region_list_append(&alloc->oob_list, reg);
661 /* Returns an ext4_inode structure for an inode number */
662 struct ext4_inode *get_inode(u32 inode)
665 int bg = inode / info.inodes_per_group;
666 inode %= info.inodes_per_group;
668 allocate_bg_inode_table(&aux_info.bgs[bg]);
669 return (struct ext4_inode *)(aux_info.bgs[bg].inode_table + inode *
673 struct ext4_xattr_header *get_xattr_block_for_inode(struct ext4_inode *inode)
675 struct ext4_xattr_header *block = xattr_list_find(inode);
679 u32 block_num = allocate_block();
680 block = calloc(info.block_size, 1);
682 error("get_xattr: failed to allocate %d", info.block_size);
686 block->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
687 block->h_refcount = cpu_to_le32(1);
688 block->h_blocks = cpu_to_le32(1);
689 inode->i_blocks_lo = cpu_to_le32(le32_to_cpu(inode->i_blocks_lo) + (info.block_size / 512));
690 inode->i_file_acl_lo = cpu_to_le32(block_num);
692 int result = sparse_file_add_data(ext4_sparse_file, block, info.block_size, block_num);
694 error("get_xattr: sparse_file_add_data failure %d", result);
698 xattr_list_insert(inode, block);
702 /* Mark the first len inodes in a block group as used */
703 u32 reserve_inodes(int bg, u32 num)
708 if (get_free_inodes(bg) < num)
709 return EXT4_ALLOCATE_FAILED;
711 for (i = 0; i < num; i++) {
712 inode = aux_info.bgs[bg].first_free_inode + i - 1;
713 aux_info.bgs[bg].inode_bitmap[inode / 8] |= 1 << (inode % 8);
716 inode = aux_info.bgs[bg].first_free_inode;
718 aux_info.bgs[bg].first_free_inode += num;
719 aux_info.bgs[bg].free_inodes -= num;
724 /* Returns the first free inode number
725 TODO: Inodes should be allocated in the block group of the data? */
731 for (bg = 0; bg < aux_info.groups; bg++) {
732 inode = reserve_inodes(bg, 1);
733 if (inode != EXT4_ALLOCATE_FAILED)
734 return bg * info.inodes_per_group + inode;
737 return EXT4_ALLOCATE_FAILED;
740 /* Returns the number of free inodes in a block group */
741 u32 get_free_inodes(u32 bg)
743 return aux_info.bgs[bg].free_inodes;
746 /* Increments the directory count of the block group that contains inode */
747 void add_directory(u32 inode)
749 int bg = (inode - 1) / info.inodes_per_group;
750 aux_info.bgs[bg].used_dirs += 1;
753 /* Returns the number of inodes in a block group that are directories */
754 u16 get_directories(int bg)
756 return aux_info.bgs[bg].used_dirs;
759 /* Returns the flags for a block group */
760 u16 get_bg_flags(int bg)
762 return aux_info.bgs[bg].flags;
765 /* Frees the memory used by a linked list of allocation regions */
766 void free_alloc(struct block_allocation *alloc)
770 reg = alloc->list.first;
772 struct region *next = reg->next;
777 reg = alloc->oob_list.first;
779 struct region *next = reg->next;
787 void reserve_bg_chunk(int bg, u32 start_block, u32 size) {
788 struct block_group_info *bgs = aux_info.bgs;
790 if (bgs[bg].chunk_count == bgs[bg].max_chunk_count) {
791 bgs[bg].max_chunk_count *= 2;
792 bgs[bg].chunks = realloc(bgs[bg].chunks, bgs[bg].max_chunk_count * sizeof(struct region));
794 critical_error("realloc failed");
796 chunk_count = bgs[bg].chunk_count;
797 bgs[bg].chunks[chunk_count].block = start_block;
798 bgs[bg].chunks[chunk_count].len = size;
799 bgs[bg].chunks[chunk_count].bg = bg;
800 bgs[bg].chunk_count++;
803 int reserve_blocks_for_allocation(struct block_allocation *alloc) {
805 struct block_group_info *bgs = aux_info.bgs;
807 if (!alloc) return 0;
808 reg = alloc->list.first;
809 while (reg != NULL) {
810 if (reserve_blocks(&bgs[reg->bg], reg->bg, reg->block - bgs[reg->bg].first_block, reg->len) < 0) {