File: /usr/src/linux/include/linux/jffs.h
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 #include <linux/completion.h>
26
27 /* This is a magic number that is used as an identification number for
28 this file system. It is written to the super_block structure. */
29 #define JFFS_MAGIC_SB_BITMASK 0x07c0 /* 1984 */
30
31 /* This is a magic number that every on-flash raw inode begins with. */
32 #define JFFS_MAGIC_BITMASK 0x34383931 /* "1984" */
33
34 /* These two bitmasks are the valid ones for the flash memories we have
35 for the moment. */
36 #define JFFS_EMPTY_BITMASK 0xffffffff
37 #define JFFS_DIRTY_BITMASK 0x00000000
38
39 /* This is the inode number of the root node. */
40 #define JFFS_MIN_INO 1
41
42 /* How many slots in the file hash table should we have? */
43 #define JFFS_HASH_SIZE 40
44
45 /* Don't use more than 254 bytes as the maximum allowed length of a file's
46 name due to errors that could occur during the scanning of the flash
47 memory. In fact, a name length of 255 or 0xff, could be the result of
48 an uncompleted write. For instance, if a raw inode is written to the
49 flash memory and there is a power lossage just before the length of
50 the name is written, the length 255 would be interpreted as an illegal
51 value. */
52 #define JFFS_MAX_NAME_LEN 254
53
54 /* Commands for ioctl(). */
55 #define JFFS_IOCTL_MAGIC 't'
56 #define JFFS_PRINT_HASH _IO(JFFS_IOCTL_MAGIC, 90)
57 #define JFFS_PRINT_TREE _IO(JFFS_IOCTL_MAGIC, 91)
58 #define JFFS_GET_STATUS _IO(JFFS_IOCTL_MAGIC, 92)
59
60 /* XXX: This is something that we should try to get rid of in the future. */
61 #define JFFS_MODIFY_INODE 0x01
62 #define JFFS_MODIFY_NAME 0x02
63 #define JFFS_MODIFY_DATA 0x04
64 #define JFFS_MODIFY_EXIST 0x08
65
66 struct jffs_control;
67
68 /* The JFFS raw inode structure: Used for storage on physical media. */
69 /* Perhaps the uid, gid, atime, mtime and ctime members should have
70 more space due to future changes in the Linux kernel. Anyhow, since
71 a user of this filesystem probably have to fix a large number of
72 other things, we have decided to not be forward compatible. */
73 struct jffs_raw_inode
74 {
75 __u32 magic; /* A constant magic number. */
76 __u32 ino; /* Inode number. */
77 __u32 pino; /* Parent's inode number. */
78 __u32 version; /* Version number. */
79 __u32 mode; /* The file's type or mode. */
80 __u16 uid; /* The file's owner. */
81 __u16 gid; /* The file's group. */
82 __u32 atime; /* Last access time. */
83 __u32 mtime; /* Last modification time. */
84 __u32 ctime; /* Creation time. */
85 __u32 offset; /* Where to begin to write. */
86 __u32 dsize; /* Size of the node's data. */
87 __u32 rsize; /* How much are going to be replaced? */
88 __u8 nsize; /* Name length. */
89 __u8 nlink; /* Number of links. */
90 __u8 spare : 6; /* For future use. */
91 __u8 rename : 1; /* Rename to a name of an already existing file? */
92 __u8 deleted : 1; /* Has this file been deleted? */
93 __u8 accurate; /* The inode is obsolete if accurate == 0. */
94 __u32 dchksum; /* Checksum for the data. */
95 __u16 nchksum; /* Checksum for the name. */
96 __u16 chksum; /* Checksum for the raw inode. */
97 };
98
99 /* Define the offset of the accurate byte in struct jffs_raw_inode. */
100 #define JFFS_RAW_INODE_ACCURATE_OFFSET (sizeof(struct jffs_raw_inode) \
101 - 2 * sizeof(__u32) - sizeof(__u8))
102
103 /* Define the offset of the chksum member in struct jffs_raw_inode. */
104 #define JFFS_RAW_INODE_CHKSUM_OFFSET (sizeof(struct jffs_raw_inode) \
105 - sizeof(__u16))
106
107 /* Define the offset of the dchksum member in struct jffs_raw_inode. */
108 #define JFFS_RAW_INODE_DCHKSUM_OFFSET (sizeof(struct jffs_raw_inode) \
109 - sizeof(__u16) - sizeof(__u16) \
110 - sizeof(__u32))
111
112
113 /* The RAM representation of the node. The names of pointers to
114 jffs_nodes are very often just called `n' in the source code. */
115 struct jffs_node
116 {
117 __u32 ino; /* Inode number. */
118 __u32 version; /* Version number. */
119 __u32 data_offset; /* Logic location of the data to insert. */
120 __u32 data_size; /* The amount of data this node inserts. */
121 __u32 removed_size; /* The amount of data that this node removes. */
122 __u32 fm_offset; /* Physical location of the data in the actual
123 flash memory data chunk. */
124 __u8 name_size; /* Size of the name. */
125 struct jffs_fm *fm; /* Physical memory information. */
126 struct jffs_node *version_prev;
127 struct jffs_node *version_next;
128 struct jffs_node *range_prev;
129 struct jffs_node *range_next;
130 };
131
132
133 /* The RAM representation of a file (plain files, directories,
134 links, etc.). Pointers to jffs_files are normally named `f'
135 in the JFFS source code. */
136 struct jffs_file
137 {
138 __u32 ino; /* Inode number. */
139 __u32 pino; /* Parent's inode number. */
140 __u32 mode; /* file_type, mode */
141 __u16 uid; /* owner */
142 __u16 gid; /* group */
143 __u32 atime; /* Last access time. */
144 __u32 mtime; /* Last modification time. */
145 __u32 ctime; /* Creation time. */
146 __u8 nsize; /* Name length. */
147 __u8 nlink; /* Number of links. */
148 __u8 deleted; /* Has this file been deleted? */
149 char *name; /* The name of this file; NULL-terminated. */
150 __u32 size; /* The total size of the file's data. */
151 __u32 highest_version; /* The highest version number of this file. */
152 struct jffs_control *c;
153 struct jffs_file *parent; /* Reference to the parent directory. */
154 struct jffs_file *children; /* Always NULL for plain files. */
155 struct jffs_file *sibling_prev; /* Siblings in the same directory. */
156 struct jffs_file *sibling_next;
157 struct list_head hash; /* hash list. */
158 struct jffs_node *range_head; /* The final data. */
159 struct jffs_node *range_tail; /* The first data. */
160 struct jffs_node *version_head; /* The youngest node. */
161 struct jffs_node *version_tail; /* The oldest node. */
162 };
163
164
165 /* This is just a definition of a simple list used for keeping track of
166 files deleted due to a rename. This list is only used during the
167 mounting of the file system and only if there have been rename operations
168 earlier. */
169 struct jffs_delete_list
170 {
171 __u32 ino;
172 struct jffs_delete_list *next;
173 };
174
175
176 /* A struct for the overall file system control. Pointers to
177 jffs_control structs are named `c' in the source code. */
178 struct jffs_control
179 {
180 struct super_block *sb; /* Reference to the VFS super block. */
181 struct jffs_file *root; /* The root directory file. */
182 struct list_head *hash; /* Hash table for finding files by ino. */
183 struct jffs_fmcontrol *fmc; /* Flash memory control structure. */
184 __u32 hash_len; /* The size of the hash table. */
185 __u32 next_ino; /* Next inode number to use for new files. */
186 __u16 building_fs; /* Is the file system being built right now? */
187 struct jffs_delete_list *delete_list; /* Track deleted files. */
188 pid_t thread_pid; /* GC thread's PID */
189 struct task_struct *gc_task; /* GC task struct */
190 struct completion gc_thread_comp; /* GC thread exit mutex */
191 __u32 gc_minfree_threshold; /* GC trigger thresholds */
192 __u32 gc_maxdirty_threshold;
193 };
194
195
196 /* Used to inform about flash status. */
197 struct jffs_flash_status
198 {
199 __u32 size;
200 __u32 used;
201 __u32 dirty;
202 __u32 begin;
203 __u32 end;
204 };
205
206 /* This stuff could be used for finding memory leaks. */
207 #define JFFS_MEMORY_DEBUG 0
208
209 #if defined(JFFS_MEMORY_DEBUG) && JFFS_MEMORY_DEBUG
210 extern long no_jffs_file;
211 extern long no_jffs_node;
212 extern long no_jffs_control;
213 extern long no_jffs_raw_inode;
214 extern long no_jffs_node_ref;
215 extern long no_jffs_fm;
216 extern long no_jffs_fmcontrol;
217 extern long no_hash;
218 extern long no_name;
219 #define DJM(x) x
220 #else
221 #define DJM(x)
222 #endif
223
224 #endif /* __LINUX_JFFS_H__ */
225