| 1 | /*
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| 2 | * Copyright (c) 2008 Jakub Jermar
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| 3 | * Copyright (c) 2011 Oleg Romanenko
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| 4 | * All rights reserved.
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| 5 | *
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| 6 | * Redistribution and use in source and binary forms, with or without
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| 7 | * modification, are permitted provided that the following conditions
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| 8 | * are met:
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| 9 | *
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| 10 | * - Redistributions of source code must retain the above copyright
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| 11 | * notice, this list of conditions and the following disclaimer.
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| 12 | * - Redistributions in binary form must reproduce the above copyright
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| 13 | * notice, this list of conditions and the following disclaimer in the
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| 14 | * documentation and/or other materials provided with the distribution.
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| 15 | * - The name of the author may not be used to endorse or promote products
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| 16 | * derived from this software without specific prior written permission.
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| 17 | *
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| 18 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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| 19 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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| 20 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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| 21 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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| 22 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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| 23 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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| 24 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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| 25 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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| 26 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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| 27 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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| 28 | */
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| 29 |
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| 30 | /** @addtogroup fs
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| 31 | * @{
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| 32 | */
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| 33 |
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| 34 | #ifndef FAT_FAT_H_
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| 35 | #define FAT_FAT_H_
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| 36 |
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| 37 | #include "fat_fat.h"
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| 38 | #include <fibril_synch.h>
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| 39 | #include <libfs.h>
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| 40 | #include <atomic.h>
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| 41 | #include <sys/types.h>
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| 42 | #include <bool.h>
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| 43 | #include "../../vfs/vfs.h"
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| 44 |
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| 45 | #ifndef dprintf
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| 46 | #define dprintf(...) printf(__VA_ARGS__)
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| 47 | #endif
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| 48 |
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| 49 | #define min(a, b) ((a) < (b) ? (a) : (b))
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| 50 |
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| 51 | /*
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| 52 | * Convenience macros for accessing some frequently used boot sector members.
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| 53 | */
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| 54 | #define BPS(bs) uint16_t_le2host((bs)->bps)
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| 55 | #define SPC(bs) (bs)->spc
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| 56 | #define RSCNT(bs) uint16_t_le2host((bs)->rscnt)
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| 57 | #define FATCNT(bs) (bs)->fatcnt
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| 58 |
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| 59 | #define SF(bs) (uint16_t_le2host((bs)->sec_per_fat) ? \
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| 60 | uint16_t_le2host((bs)->sec_per_fat) : \
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| 61 | uint32_t_le2host(bs->fat32.sectors_per_fat))
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| 62 |
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| 63 | #define RDE(bs) uint16_t_le2host((bs)->root_ent_max)
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| 64 |
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| 65 | #define TS(bs) (uint16_t_le2host((bs)->totsec16) ? \
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| 66 | uint16_t_le2host((bs)->totsec16) : \
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| 67 | uint32_t_le2host(bs->totsec32))
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| 68 |
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| 69 | #define BS_BLOCK 0
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| 70 | #define BS_SIZE 512
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| 71 |
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| 72 | typedef struct fat_bs {
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| 73 | uint8_t ji[3]; /**< Jump instruction. */
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| 74 | uint8_t oem_name[8];
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| 75 | /* BIOS Parameter Block */
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| 76 | uint16_t bps; /**< Bytes per sector. */
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| 77 | uint8_t spc; /**< Sectors per cluster. */
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| 78 | uint16_t rscnt; /**< Reserved sector count. */
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| 79 | uint8_t fatcnt; /**< Number of FATs. */
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| 80 | uint16_t root_ent_max; /**< Maximum number of root directory
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| 81 | entries. */
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| 82 | uint16_t totsec16; /**< Total sectors. 16-bit version. */
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| 83 | uint8_t mdesc; /**< Media descriptor. */
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| 84 | uint16_t sec_per_fat; /**< Sectors per FAT12/FAT16. */
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| 85 | uint16_t sec_per_track; /**< Sectors per track. */
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| 86 | uint16_t headcnt; /**< Number of heads. */
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| 87 | uint32_t hidden_sec; /**< Hidden sectors. */
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| 88 | uint32_t totsec32; /**< Total sectors. 32-bit version. */
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| 89 |
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| 90 | union {
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| 91 | struct {
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| 92 | /* FAT12/FAT16 only: Extended BIOS Parameter Block */
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| 93 | /** Physical drive number. */
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| 94 | uint8_t pdn;
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| 95 | uint8_t reserved;
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| 96 | /** Extended boot signature. */
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| 97 | uint8_t ebs;
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| 98 | /** Serial number. */
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| 99 | uint32_t id;
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| 100 | /** Volume label. */
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| 101 | uint8_t label[11];
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| 102 | /** FAT type. */
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| 103 | uint8_t type[8];
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| 104 | /** Boot code. */
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| 105 | uint8_t boot_code[448];
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| 106 | /** Boot sector signature. */
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| 107 | uint16_t signature;
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| 108 | } __attribute__ ((packed));
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| 109 | struct {
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| 110 | /* FAT32 only */
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| 111 | /** Sectors per FAT. */
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| 112 | uint32_t sectors_per_fat;
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| 113 | /** FAT flags. */
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| 114 | uint16_t flags;
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| 115 | /** Version. */
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| 116 | uint16_t version;
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| 117 | /** Cluster number of root directory. */
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| 118 | uint32_t root_cluster;
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| 119 | /** Sector number of file system information sector. */
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| 120 | uint16_t fsinfo_sec;
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| 121 | /** Sector number of boot sector copy. */
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| 122 | uint16_t bscopy_sec;
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| 123 | uint8_t reserved1[12];
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| 124 | /** Physical drive number. */
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| 125 | uint8_t pdn;
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| 126 | uint8_t reserved2;
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| 127 | /** Extended boot signature. */
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| 128 | uint8_t ebs;
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| 129 | /** Serial number. */
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| 130 | uint32_t id;
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| 131 | /** Volume label. */
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| 132 | uint8_t label[11];
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| 133 | /** FAT type. */
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| 134 | uint8_t type[8];
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| 135 | /** Boot code. */
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| 136 | uint8_t boot_code[420];
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| 137 | /** Signature. */
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| 138 | uint16_t signature;
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| 139 | } fat32 __attribute__ ((packed));
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| 140 | };
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| 141 | } __attribute__ ((packed)) fat_bs_t;
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| 142 |
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| 143 | typedef enum {
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| 144 | FAT_INVALID,
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| 145 | FAT_DIRECTORY,
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| 146 | FAT_FILE
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| 147 | } fat_node_type_t;
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| 148 |
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| 149 | struct fat_node;
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| 150 |
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| 151 | /** FAT index structure.
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| 152 | *
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| 153 | * This structure exists to help us to overcome certain limitations of the FAT
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| 154 | * file system design. The problem with FAT is that it is hard to find
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| 155 | * an entity which could represent a VFS index. There are two candidates:
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| 156 | *
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| 157 | * a) number of the node's first cluster
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| 158 | * b) the pair of the parent directory's first cluster and the dentry index
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| 159 | * within the parent directory
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| 160 | *
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| 161 | * We need VFS indices to be:
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| 162 | * A) unique
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| 163 | * B) stable in time, at least until the next mount
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| 164 | *
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| 165 | * Unfortunately a) does not meet the A) criterion because zero-length files
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| 166 | * will have the first cluster field cleared. And b) does not meet the B)
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| 167 | * criterion because unlink() and rename() will both free up the original
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| 168 | * dentry, which contains all the essential info about the file.
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| 169 | *
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| 170 | * Therefore, a completely opaque indices are used and the FAT server maintains
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| 171 | * a mapping between them and otherwise nice b) variant. On rename(), the VFS
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| 172 | * index stays unaltered, while the internal FAT "physical tree address"
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| 173 | * changes. The unlink case is also handled this way thanks to an in-core node
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| 174 | * pointer embedded in the index structure.
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| 175 | */
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| 176 | typedef struct {
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| 177 | /** Used indices (position) hash table link. */
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| 178 | link_t uph_link;
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| 179 | /** Used indices (index) hash table link. */
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| 180 | link_t uih_link;
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| 181 |
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| 182 | fibril_mutex_t lock;
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| 183 | service_id_t service_id;
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| 184 | fs_index_t index;
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| 185 | /**
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| 186 | * Parent node's first cluster.
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| 187 | * Zero is used if this node is not linked, in which case nodep must
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| 188 | * contain a pointer to the in-core node structure.
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| 189 | * One is used when the parent is the root directory.
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| 190 | */
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| 191 | fat_cluster_t pfc;
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| 192 | /** Directory entry index within the parent node. */
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| 193 | unsigned pdi;
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| 194 | /** Pointer to in-core node instance. */
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| 195 | struct fat_node *nodep;
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| 196 | } fat_idx_t;
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| 197 |
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| 198 | /** FAT in-core node. */
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| 199 | typedef struct fat_node {
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| 200 | /** Back pointer to the FS node. */
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| 201 | fs_node_t *bp;
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| 202 |
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| 203 | fibril_mutex_t lock;
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| 204 | fat_node_type_t type;
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| 205 | fat_idx_t *idx;
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| 206 | /**
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| 207 | * Node's first cluster.
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| 208 | * Zero is used for zero-length nodes.
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| 209 | * One is used to mark root directory.
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| 210 | */
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| 211 | fat_cluster_t firstc;
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| 212 | /** FAT in-core node free list link. */
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| 213 | link_t ffn_link;
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| 214 | aoff64_t size;
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| 215 | unsigned lnkcnt;
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| 216 | unsigned refcnt;
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| 217 | bool dirty;
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| 218 |
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| 219 | /*
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| 220 | * Cache of the node's last and "current" cluster to avoid some
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| 221 | * unnecessary FAT walks.
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| 222 | */
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| 223 | /* Node's last cluster in FAT. */
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| 224 | bool lastc_cached_valid;
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| 225 | fat_cluster_t lastc_cached_value;
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| 226 | /* Node's "current" cluster, i.e. where the last I/O took place. */
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| 227 | bool currc_cached_valid;
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| 228 | aoff64_t currc_cached_bn;
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| 229 | fat_cluster_t currc_cached_value;
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| 230 | } fat_node_t;
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| 231 |
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| 232 | extern vfs_out_ops_t fat_ops;
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| 233 | extern libfs_ops_t fat_libfs_ops;
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| 234 |
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| 235 | extern int fat_idx_get_new(fat_idx_t **, service_id_t);
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| 236 | extern fat_idx_t *fat_idx_get_by_pos(service_id_t, fat_cluster_t, unsigned);
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| 237 | extern fat_idx_t *fat_idx_get_by_index(service_id_t, fs_index_t);
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| 238 | extern void fat_idx_destroy(fat_idx_t *);
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| 239 | extern void fat_idx_hashin(fat_idx_t *);
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| 240 | extern void fat_idx_hashout(fat_idx_t *);
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| 241 |
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| 242 | extern int fat_idx_init(void);
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| 243 | extern void fat_idx_fini(void);
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| 244 | extern int fat_idx_init_by_service_id(service_id_t);
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| 245 | extern void fat_idx_fini_by_service_id(service_id_t);
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| 246 |
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| 247 | #endif
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| 248 |
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| 249 | /**
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| 250 | * @}
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| 251 | */
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