source: mainline/uspace/srv/fs/fat/fat.h@ 50e5b25

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since 50e5b25 was 50e5b25, checked in by Jakub Jermar <jakub@…>, 17 years ago

Add implementation of fat_destroy_node() and fat_destroy().

  • Property mode set to 100644
File size: 6.8 KB
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1/*
2 * Copyright (c) 2008 Jakub Jermar
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * - Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * - Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * - The name of the author may not be used to endorse or promote products
15 * derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29/** @addtogroup fs
30 * @{
31 */
32
33#ifndef FAT_FAT_H_
34#define FAT_FAT_H_
35
36#include "fat_fat.h"
37#include <ipc/ipc.h>
38#include <libfs.h>
39#include <atomic.h>
40#include <sys/types.h>
41#include <bool.h>
42#include "../../vfs/vfs.h"
43
44#ifndef dprintf
45#define dprintf(...) printf(__VA_ARGS__)
46#endif
47
48#define min(a, b) ((a) < (b) ? (a) : (b))
49
50#define BS_BLOCK 0
51#define BS_SIZE 512
52
53typedef struct fat_bs {
54 uint8_t ji[3]; /**< Jump instruction. */
55 uint8_t oem_name[8];
56 /* BIOS Parameter Block */
57 uint16_t bps; /**< Bytes per sector. */
58 uint8_t spc; /**< Sectors per cluster. */
59 uint16_t rscnt; /**< Reserved sector count. */
60 uint8_t fatcnt; /**< Number of FATs. */
61 uint16_t root_ent_max; /**< Maximum number of root directory
62 entries. */
63 uint16_t totsec16; /**< Total sectors. 16-bit version. */
64 uint8_t mdesc; /**< Media descriptor. */
65 uint16_t sec_per_fat; /**< Sectors per FAT12/FAT16. */
66 uint16_t sec_per_track; /**< Sectors per track. */
67 uint16_t headcnt; /**< Number of heads. */
68 uint32_t hidden_sec; /**< Hidden sectors. */
69 uint32_t totsec32; /**< Total sectors. 32-bit version. */
70
71 union {
72 struct {
73 /* FAT12/FAT16 only: Extended BIOS Parameter Block */
74 /** Physical drive number. */
75 uint8_t pdn;
76 uint8_t reserved;
77 /** Extended boot signature. */
78 uint8_t ebs;
79 /** Serial number. */
80 uint32_t id;
81 /** Volume label. */
82 uint8_t label[11];
83 /** FAT type. */
84 uint8_t type[8];
85 /** Boot code. */
86 uint8_t boot_code[448];
87 /** Boot sector signature. */
88 uint16_t signature;
89 } __attribute__ ((packed));
90 struct {
91 /* FAT32 only */
92 /** Sectors per FAT. */
93 uint32_t sectors_per_fat;
94 /** FAT flags. */
95 uint16_t flags;
96 /** Version. */
97 uint16_t version;
98 /** Cluster number of root directory. */
99 uint32_t root_cluster;
100 /** Sector number of file system information sector. */
101 uint16_t fsinfo_sec;
102 /** Sector number of boot sector copy. */
103 uint16_t bscopy_sec;
104 uint8_t reserved1[12];
105 /** Physical drive number. */
106 uint8_t pdn;
107 uint8_t reserved2;
108 /** Extended boot signature. */
109 uint8_t ebs;
110 /** Serial number. */
111 uint32_t id;
112 /** Volume label. */
113 uint8_t label[11];
114 /** FAT type. */
115 uint8_t type[8];
116 /** Boot code. */
117 uint8_t boot_code[420];
118 /** Signature. */
119 uint16_t signature;
120 } __attribute__ ((packed));
121 };
122} __attribute__ ((packed)) fat_bs_t;
123
124typedef enum {
125 FAT_INVALID,
126 FAT_DIRECTORY,
127 FAT_FILE
128} fat_node_type_t;
129
130struct fat_node;
131
132/** FAT index structure.
133 *
134 * This structure exists to help us to overcome certain limitations of the FAT
135 * file system design. The problem with FAT is that it is hard to find
136 * an entity which could represent a VFS index. There are two candidates:
137 *
138 * a) number of the node's first cluster
139 * b) the pair of the parent directory's first cluster and the dentry index
140 * within the parent directory
141 *
142 * We need VFS indices to be:
143 * A) unique
144 * B) stable in time, at least until the next mount
145 *
146 * Unfortunately a) does not meet the A) criterion because zero-length files
147 * will have the first cluster field cleared. And b) does not meet the B)
148 * criterion because unlink() and rename() will both free up the original
149 * dentry, which contains all the essential info about the file.
150 *
151 * Therefore, a completely opaque indices are used and the FAT server maintains
152 * a mapping between them and otherwise nice b) variant. On rename(), the VFS
153 * index stays unaltered, while the internal FAT "physical tree address"
154 * changes. The unlink case is also handled this way thanks to an in-core node
155 * pointer embedded in the index structure.
156 */
157typedef struct {
158 /** Used indices (position) hash table link. */
159 link_t uph_link;
160 /** Used indices (index) hash table link. */
161 link_t uih_link;
162
163 futex_t lock;
164 dev_handle_t dev_handle;
165 fs_index_t index;
166 /**
167 * Parent node's first cluster.
168 * Zero is used if this node is not linked, in which case nodep must
169 * contain a pointer to the in-core node structure.
170 * One is used when the parent is the root directory.
171 */
172 fat_cluster_t pfc;
173 /** Directory entry index within the parent node. */
174 unsigned pdi;
175 /** Pointer to in-core node instance. */
176 struct fat_node *nodep;
177} fat_idx_t;
178
179/** FAT in-core node. */
180typedef struct fat_node {
181 futex_t lock;
182 fat_node_type_t type;
183 fat_idx_t *idx;
184 /**
185 * Node's first cluster.
186 * Zero is used for zero-length nodes.
187 * One is used to mark root directory.
188 */
189 fat_cluster_t firstc;
190 /** FAT in-core node free list link. */
191 link_t ffn_link;
192 size_t size;
193 unsigned lnkcnt;
194 unsigned refcnt;
195 bool dirty;
196} fat_node_t;
197
198extern fs_reg_t fat_reg;
199
200extern void fat_mounted(ipc_callid_t, ipc_call_t *);
201extern void fat_mount(ipc_callid_t, ipc_call_t *);
202extern void fat_lookup(ipc_callid_t, ipc_call_t *);
203extern void fat_read(ipc_callid_t, ipc_call_t *);
204extern void fat_write(ipc_callid_t, ipc_call_t *);
205extern void fat_truncate(ipc_callid_t, ipc_call_t *);
206extern void fat_destroy(ipc_callid_t, ipc_call_t *);
207
208extern fat_idx_t *fat_idx_get_new(dev_handle_t);
209extern fat_idx_t *fat_idx_get_by_pos(dev_handle_t, fat_cluster_t, unsigned);
210extern fat_idx_t *fat_idx_get_by_index(dev_handle_t, fs_index_t);
211extern void fat_idx_destroy(fat_idx_t *);
212
213extern int fat_idx_init(void);
214extern void fat_idx_fini(void);
215extern int fat_idx_init_by_dev_handle(dev_handle_t);
216extern void fat_idx_fini_by_dev_handle(dev_handle_t);
217
218#endif
219
220/**
221 * @}
222 */
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