| 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 | #ifndef LIBEXT4_LIBEXT4_EXTENT_H_
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| 34 | #define LIBEXT4_LIBEXT4_EXTENT_H_
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| 35 |
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| 36 | /*
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| 37 | * This is the extent on-disk structure.
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| 38 | * It's used at the bottom of the tree.
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| 39 | */
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| 40 | typedef struct ext4_extent {
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| 41 | uint32_t first_block; // First logical block extent covers
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| 42 | uint16_t block_count; // Number of blocks covered by extent
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| 43 | uint16_t start_hi; // High 16 bits of physical block
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| 44 | uint32_t start_lo; // Low 32 bits of physical block
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| 45 | } ext4_extent_t;
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| 46 |
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| 47 | /*
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| 48 | * This is index on-disk structure.
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| 49 | * It's used at all the levels except the bottom.
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| 50 | */
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| 51 | typedef struct ext4_extent_index {
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| 52 | uint32_t first_block; // Index covers logical blocks from 'block'
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| 53 | uint32_t leaf_lo; /* Pointer to the physical block of the next
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| 54 | * level. leaf or next index could be there */
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| 55 | uint16_t leaf_hi; /* high 16 bits of physical block */
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| 56 | uint16_t padding;
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| 57 | } ext4_extent_index_t;
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| 58 |
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| 59 | /*
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| 60 | * Each block (leaves and indexes), even inode-stored has header.
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| 61 | */
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| 62 | typedef struct ext4_extent_header {
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| 63 | uint16_t magic;
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| 64 | uint16_t entries_count; // Number of valid entries
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| 65 | uint16_t max_entries_count; // Capacity of store in entries
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| 66 | uint16_t depth; // Has tree real underlying blocks?
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| 67 | uint32_t generation; // generation of the tree
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| 68 | } ext4_extent_header_t;
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| 69 |
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| 70 | #define EXT4_EXTENT_MAGIC 0xF30A
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| 71 | #define EXT4_EXTENT_FIRST(header) \
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| 72 | ((ext4_extent_t *) (((void *) (header)) + sizeof(ext4_extent_header_t)))
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| 73 | #define EXT4_EXTENT_FIRST_INDEX(header) \
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| 74 | ((ext4_extent_index_t *) (((void *) (header)) + sizeof(ext4_extent_header_t)))
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| 75 |
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| 76 | extern uint32_t ext4_extent_get_first_block(ext4_extent_t *);
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| 77 | extern uint16_t ext4_extent_get_block_count(ext4_extent_t *);
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| 78 | extern uint64_t ext4_extent_get_start(ext4_extent_t *);
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| 79 |
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| 80 | extern uint32_t ext4_extent_index_get_first_block(ext4_extent_index_t *);
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| 81 | extern uint64_t ext4_extent_index_get_leaf(ext4_extent_index_t *);
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| 82 |
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| 83 | extern uint16_t ext4_extent_header_get_magic(ext4_extent_header_t *);
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| 84 | extern uint16_t ext4_extent_header_get_entries_count(ext4_extent_header_t *);
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| 85 | extern uint16_t ext4_extent_header_get_max_entries_count(ext4_extent_header_t *);
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| 86 | extern uint16_t ext4_extent_header_get_depth(ext4_extent_header_t *);
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| 87 | extern uint32_t ext4_extent_header_get_generation(ext4_extent_header_t *);
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| 88 |
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| 89 | #endif
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| 90 |
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| 91 | /**
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| 92 | * @}
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| 93 | */
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