| 1 | /*
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| 2 | * Copyright (c) 2011 Frantisek Princ
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| 3 | * All rights reserved.
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| 4 | *
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| 5 | * Redistribution and use in source and binary forms, with or without
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| 6 | * modification, are permitted provided that the following conditions
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| 7 | * are met:
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| 8 | *
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| 9 | * - Redistributions of source code must retain the above copyright
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| 10 | * notice, this list of conditions and the following disclaimer.
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| 11 | * - Redistributions in binary form must reproduce the above copyright
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| 12 | * notice, this list of conditions and the following disclaimer in the
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| 13 | * documentation and/or other materials provided with the distribution.
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| 14 | * - The name of the author may not be used to endorse or promote products
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| 15 | * derived from this software without specific prior written permission.
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| 16 | *
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| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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| 27 | */
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| 28 |
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| 29 | /** @addtogroup libext4
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| 30 | * @{
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| 31 | */
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| 32 |
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| 33 | /**
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| 34 | * @file libext4_bitmap.c
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| 35 | * @brief TODO
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| 36 | */
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| 37 |
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| 38 | #include <errno.h>
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| 39 | #include <libblock.h>
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| 40 | #include <sys/types.h>
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| 41 | #include "libext4.h"
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| 42 |
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| 43 | static void ext4_bitmap_free_bit(uint8_t *bitmap, uint32_t index)
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| 44 | {
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| 45 | uint32_t byte_index = index / 8;
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| 46 | uint32_t bit_index = index % 8;
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| 47 |
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| 48 | uint8_t *target = bitmap + byte_index;
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| 49 | uint8_t old_value = *target;
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| 50 |
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| 51 | uint8_t new_value = old_value & (~ (1 << bit_index));
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| 52 |
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| 53 | *target = new_value;
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| 54 | }
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| 55 |
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| 56 | int ext4_bitmap_free_block(ext4_filesystem_t *fs, uint32_t block_index)
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| 57 | {
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| 58 | int rc;
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| 59 | uint32_t blocks_per_group;
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| 60 | uint32_t block_group;
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| 61 | uint32_t index_in_group;
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| 62 | uint32_t bitmap_block;
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| 63 | ext4_block_group_ref_t *bg_ref;
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| 64 | block_t *block;
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| 65 |
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| 66 | blocks_per_group = ext4_superblock_get_blocks_per_group(fs->superblock);
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| 67 | block_group = block_index / blocks_per_group;
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| 68 | index_in_group = block_index % blocks_per_group;
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| 69 |
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| 70 | rc = ext4_filesystem_get_block_group_ref(fs, block_group, &bg_ref);
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| 71 | if (rc != EOK) {
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| 72 | return rc;
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| 73 | }
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| 74 |
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| 75 | bitmap_block = ext4_block_group_get_block_bitmap(bg_ref->block_group);
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| 76 |
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| 77 | rc = block_get(&block, fs->device, bitmap_block, 0);
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| 78 | if (rc != EOK) {
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| 79 | return rc;
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| 80 | }
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| 81 |
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| 82 | ext4_bitmap_free_bit(block->data, index_in_group);
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| 83 |
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| 84 | block->dirty = true;
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| 85 | rc = block_put(block);
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| 86 | if (rc != EOK) {
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| 87 | return rc;
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| 88 | }
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| 89 |
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| 90 | uint32_t free_blocks = ext4_block_group_get_free_blocks_count(bg_ref->block_group);
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| 91 | free_blocks++;
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| 92 | ext4_block_group_set_free_blocks_count(bg_ref->block_group, free_blocks);
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| 93 |
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| 94 | rc = ext4_filesystem_put_block_group_ref(bg_ref);
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| 95 | if (rc != EOK) {
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| 96 | // TODO error
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| 97 | return rc;
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| 98 | }
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| 99 |
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| 100 | return EOK;
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| 101 | }
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| 102 |
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| 103 |
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| 104 | /**
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| 105 | * @}
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| 106 | */
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