1 /*
2 * JFFS -- Journalling Flash File System, Linux implementation.
3 *
4 * Copyright (C) 1999, 2000 Axis Communications AB.
5 *
6 * Created by Finn Hakansson <finn@axis.com>.
7 *
8 * This is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * $Id: jffs.h,v 1.11 2000/08/04 12:46:34 dwmw2 Exp $
14 *
15 * Ported to Linux 2.3.x and MTD:
16 * Copyright (C) 2000 Alexander Larsson (alex@cendio.se), Cendio Systems AB
17 *
18 */
19
20 #ifndef __LINUX_JFFS_H__
21 #define __LINUX_JFFS_H__
22
23 #define JFFS_VERSION_STRING "1.0"
24
25 /* This is a magic number that is used as an identification number for
26 this file system. It is written to the super_block structure. */
27 #define JFFS_MAGIC_SB_BITMASK 0x07c0 /* 1984 */
28
29 /* This is a magic number that every on-flash raw inode begins with. */
30 #define JFFS_MAGIC_BITMASK 0x34383931 /* "1984" */
31
32 /* These two bitmasks are the valid ones for the flash memories we have
33 for the moment. */
34 #define JFFS_EMPTY_BITMASK 0xffffffff
35 #define JFFS_DIRTY_BITMASK 0x00000000
36
37 /* This is the inode number of the root node. */
38 #define JFFS_MIN_INO 1
39
40 /* How many slots in the file hash table should we have? */
41 #define JFFS_HASH_SIZE 40
42
43 /* Don't use more than 254 bytes as the maximum allowed length of a file's
44 name due to errors that could occur during the scanning of the flash
45 memory. In fact, a name length of 255 or 0xff, could be the result of
46 an uncompleted write. For instance, if a raw inode is written to the
47 flash memory and there is a power lossage just before the length of
48 the name is written, the length 255 would be interpreted as an illegal
49 value. */
50 #define JFFS_MAX_NAME_LEN 254
51
52 /* Commands for ioctl(). */
53 #define JFFS_IOCTL_MAGIC 't'
54 #define JFFS_PRINT_HASH _IO(JFFS_IOCTL_MAGIC, 90)
55 #define JFFS_PRINT_TREE _IO(JFFS_IOCTL_MAGIC, 91)
56 #define JFFS_GET_STATUS _IO(JFFS_IOCTL_MAGIC, 92)
57
58 /* XXX: This is something that we should try to get rid of in the future. */
59 #define JFFS_MODIFY_INODE 0x01
60 #define JFFS_MODIFY_NAME 0x02
61 #define JFFS_MODIFY_DATA 0x04
62 #define JFFS_MODIFY_EXIST 0x08
63
64 struct jffs_control;
65
66 /* The JFFS raw inode structure: Used for storage on physical media. */
67 /* Perhaps the uid, gid, atime, mtime and ctime members should have
68 more space due to future changes in the Linux kernel. Anyhow, since
69 a user of this filesystem probably have to fix a large number of
70 other things, we have decided to not be forward compatible. */
71 struct jffs_raw_inode
72 {
73 __u32 magic; /* A constant magic number. */
74 __u32 ino; /* Inode number. */
75 __u32 pino; /* Parent's inode number. */
76 __u32 version; /* Version number. */
77 __u32 mode; /* The file's type or mode. */
78 __u16 uid; /* The file's owner. */
79 __u16 gid; /* The file's group. */
80 __u32 atime; /* Last access time. */
81 __u32 mtime; /* Last modification time. */
82 __u32 ctime; /* Creation time. */
83 __u32 offset; /* Where to begin to write. */
84 __u32 dsize; /* Size of the node's data. */
85 __u32 rsize; /* How much are going to be replaced? */
86 __u8 nsize; /* Name length. */
87 __u8 nlink; /* Number of links. */
88 __u8 spare : 6; /* For future use. */
89 __u8 rename : 1; /* Rename to a name of an already existing file? */
90 __u8 deleted : 1; /* Has this file been deleted? */
91 __u8 accurate; /* The inode is obsolete if accurate == 0. */
92 __u32 dchksum; /* Checksum for the data. */
93 __u16 nchksum; /* Checksum for the name. */
94 __u16 chksum; /* Checksum for the raw inode. */
95 };
96
97 /* Define the offset of the accurate byte in struct jffs_raw_inode. */
98 #define JFFS_RAW_INODE_ACCURATE_OFFSET (sizeof(struct jffs_raw_inode) \
99 - 2 * sizeof(__u32) - sizeof(__u8))
100
101 /* Define the offset of the chksum member in struct jffs_raw_inode. */
102 #define JFFS_RAW_INODE_CHKSUM_OFFSET (sizeof(struct jffs_raw_inode) \
103 - sizeof(__u16))
104
105 /* Define the offset of the dchksum member in struct jffs_raw_inode. */
106 #define JFFS_RAW_INODE_DCHKSUM_OFFSET (sizeof(struct jffs_raw_inode) \
107 - sizeof(__u16) - sizeof(__u16) \
108 - sizeof(__u32))
109
110
111 /* The RAM representation of the node. The names of pointers to
112 jffs_nodes are very often just called `n' in the source code. */
113 struct jffs_node
114 {
115 __u32 ino; /* Inode number. */
116 __u32 version; /* Version number. */
117 __u32 data_offset; /* Logic location of the data to insert. */
118 __u32 data_size; /* The amount of data this node inserts. */
119 __u32 removed_size; /* The amount of data that this node removes. */
120 __u32 fm_offset; /* Physical location of the data in the actual
121 flash memory data chunk. */
122 __u8 name_size; /* Size of the name. */
123 struct jffs_fm *fm; /* Physical memory information. */
124 struct jffs_node *version_prev;
125 struct jffs_node *version_next;
126 struct jffs_node *range_prev;
127 struct jffs_node *range_next;
128 };
129
130
131 /* The RAM representation of a file (plain files, directories,
132 links, etc.). Pointers to jffs_files are normally named `f'
133 in the JFFS source code. */
134 struct jffs_file
135 {
136 __u32 ino; /* Inode number. */
137 __u32 pino; /* Parent's inode number. */
138 __u32 mode; /* file_type, mode */
139 __u16 uid; /* owner */
140 __u16 gid; /* group */
141 __u32 atime; /* Last access time. */
142 __u32 mtime; /* Last modification time. */
143 __u32 ctime; /* Creation time. */
144 __u8 nsize; /* Name length. */
145 __u8 nlink; /* Number of links. */
146 __u8 deleted; /* Has this file been deleted? */
147 char *name; /* The name of this file; NULL-terminated. */
148 __u32 size; /* The total size of the file's data. */
149 __u32 highest_version; /* The highest version number of this file. */
150 struct jffs_control *c;
151 struct jffs_file *parent; /* Reference to the parent directory. */
152 struct jffs_file *children; /* Always NULL for plain files. */
153 struct jffs_file *sibling_prev; /* Siblings in the same directory. */
154 struct jffs_file *sibling_next;
155 struct list_head hash; /* hash list. */
156 struct jffs_node *range_head; /* The final data. */
157 struct jffs_node *range_tail; /* The first data. */
158 struct jffs_node *version_head; /* The youngest node. */
159 struct jffs_node *version_tail; /* The oldest node. */
160 };
161
162
163 /* This is just a definition of a simple list used for keeping track of
164 files deleted due to a rename. This list is only used during the
165 mounting of the file system and only if there have been rename operations
166 earlier. */
167 struct jffs_delete_list
168 {
169 __u32 ino;
170 struct jffs_delete_list *next;
171 };
172
173
174 /* A struct for the overall file system control. Pointers to
175 jffs_control structs are named `c' in the source code. */
176 struct jffs_control
177 {
178 struct super_block *sb; /* Reference to the VFS super block. */
179 struct jffs_file *root; /* The root directory file. */
180 struct list_head *hash; /* Hash table for finding files by ino. */
181 struct jffs_fmcontrol *fmc; /* Flash memory control structure. */
182 __u32 hash_len; /* The size of the hash table. */
183 __u32 next_ino; /* Next inode number to use for new files. */
184 __u16 building_fs; /* Is the file system being built right now? */
185 struct jffs_delete_list *delete_list; /* Track deleted files. */
186 pid_t thread_pid; /* GC thread's PID */
187 struct task_struct *gc_task; /* GC task struct */
188 struct semaphore gc_thread_sem; /* GC thread exit mutex */
189 __u32 gc_minfree_threshold; /* GC trigger thresholds */
190 __u32 gc_maxdirty_threshold;
191 };
192
193
194 /* Used to inform about flash status. */
195 struct jffs_flash_status
196 {
197 __u32 size;
198 __u32 used;
199 __u32 dirty;
200 __u32 begin;
201 __u32 end;
202 };
203
204 /* This stuff could be used for finding memory leaks. */
205 #define JFFS_MEMORY_DEBUG 0
206
207 #if defined(JFFS_MEMORY_DEBUG) && JFFS_MEMORY_DEBUG
208 extern long no_jffs_file;
209 extern long no_jffs_node;
210 extern long no_jffs_control;
211 extern long no_jffs_raw_inode;
212 extern long no_jffs_node_ref;
213 extern long no_jffs_fm;
214 extern long no_jffs_fmcontrol;
215 extern long no_hash;
216 extern long no_name;
217 #define DJM(x) x
218 #else
219 #define DJM(x)
220 #endif
221
222 #endif /* __LINUX_JFFS_H__ */
223
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