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gerrit-public.fairphone.software / kernel / msm-4.19 / d33a56d3639eba077489c937943a32ef6237b1b8 / . / include / linux / jffs.h
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Linus Torvalds1da177e2005-04-16 15:20:36 -0700[diff] [blame]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 1.20 2001/09/18 21:33:37 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#include <linux/types.h>
24#include <linux/completion.h>
25
26#define JFFS_VERSION_STRING "1.0"
27
28/* This is a magic number that is used as an identification number for
29 this file system. It is written to the super_block structure. */
30#define JFFS_MAGIC_SB_BITMASK 0x07c0 /* 1984 */
31
32/* This is a magic number that every on-flash raw inode begins with. */
33#define JFFS_MAGIC_BITMASK 0x34383931 /* "1984" */
34
35/* These two bitmasks are the valid ones for the flash memories we have
36 for the moment. */
37#define JFFS_EMPTY_BITMASK 0xffffffff
38#define JFFS_DIRTY_BITMASK 0x00000000
39
40/* This is the inode number of the root node. */
41#define JFFS_MIN_INO 1
42
43/* How many slots in the file hash table should we have? */
44#define JFFS_HASH_SIZE 40
45
46/* Don't use more than 254 bytes as the maximum allowed length of a file's
47 name due to errors that could occur during the scanning of the flash
48 memory. In fact, a name length of 255 or 0xff, could be the result of
49 an uncompleted write. For instance, if a raw inode is written to the
50 flash memory and there is a power lossage just before the length of
51 the name is written, the length 255 would be interpreted as an illegal
52 value. */
53#define JFFS_MAX_NAME_LEN 254
54
55/* Commands for ioctl(). */
56#define JFFS_IOCTL_MAGIC 't'
57#define JFFS_PRINT_HASH _IO(JFFS_IOCTL_MAGIC, 90)
58#define JFFS_PRINT_TREE _IO(JFFS_IOCTL_MAGIC, 91)
59#define JFFS_GET_STATUS _IO(JFFS_IOCTL_MAGIC, 92)
60
61/* XXX: This is something that we should try to get rid of in the future. */
62#define JFFS_MODIFY_INODE 0x01
63#define JFFS_MODIFY_NAME 0x02
64#define JFFS_MODIFY_DATA 0x04
65#define JFFS_MODIFY_EXIST 0x08
66
67struct jffs_control;
68
69/* The JFFS raw inode structure: Used for storage on physical media. */
70/* Perhaps the uid, gid, atime, mtime and ctime members should have
71 more space due to future changes in the Linux kernel. Anyhow, since
72 a user of this filesystem probably have to fix a large number of
73 other things, we have decided to not be forward compatible. */
74struct jffs_raw_inode
75{
76 __u32 magic; /* A constant magic number. */
77 __u32 ino; /* Inode number. */
78 __u32 pino; /* Parent's inode number. */
79 __u32 version; /* Version number. */
80 __u32 mode; /* The file's type or mode. */
81 __u16 uid; /* The file's owner. */
82 __u16 gid; /* The file's group. */
83 __u32 atime; /* Last access time. */
84 __u32 mtime; /* Last modification time. */
85 __u32 ctime; /* Creation time. */
86 __u32 offset; /* Where to begin to write. */
87 __u32 dsize; /* Size of the node's data. */
88 __u32 rsize; /* How much are going to be replaced? */
89 __u8 nsize; /* Name length. */
90 __u8 nlink; /* Number of links. */
91 __u8 spare : 6; /* For future use. */
92 __u8 rename : 1; /* Rename to a name of an already existing file? */
93 __u8 deleted : 1; /* Has this file been deleted? */
94 __u8 accurate; /* The inode is obsolete if accurate == 0. */
95 __u32 dchksum; /* Checksum for the data. */
96 __u16 nchksum; /* Checksum for the name. */
97 __u16 chksum; /* Checksum for the raw inode. */
98};
99
100/* Define the offset of the accurate byte in struct jffs_raw_inode. */
101#define JFFS_RAW_INODE_ACCURATE_OFFSET (sizeof(struct jffs_raw_inode) \
102 - 2 * sizeof(__u32) - sizeof(__u8))
103
104/* Define the offset of the chksum member in struct jffs_raw_inode. */
105#define JFFS_RAW_INODE_CHKSUM_OFFSET (sizeof(struct jffs_raw_inode) \
106 - sizeof(__u16))
107
108/* Define the offset of the dchksum member in struct jffs_raw_inode. */
109#define JFFS_RAW_INODE_DCHKSUM_OFFSET (sizeof(struct jffs_raw_inode) \
110 - sizeof(__u16) - sizeof(__u16) \
111 - sizeof(__u32))
112
113
114/* The RAM representation of the node. The names of pointers to
115 jffs_nodes are very often just called `n' in the source code. */
116struct jffs_node
117{
118 __u32 ino; /* Inode number. */
119 __u32 version; /* Version number. */
120 __u32 data_offset; /* Logic location of the data to insert. */
121 __u32 data_size; /* The amount of data this node inserts. */
122 __u32 removed_size; /* The amount of data that this node removes. */
123 __u32 fm_offset; /* Physical location of the data in the actual
124 flash memory data chunk. */
125 __u8 name_size; /* Size of the name. */
126 struct jffs_fm *fm; /* Physical memory information. */
127 struct jffs_node *version_prev;
128 struct jffs_node *version_next;
129 struct jffs_node *range_prev;
130 struct jffs_node *range_next;
131};
132
133
134/* The RAM representation of a file (plain files, directories,
135 links, etc.). Pointers to jffs_files are normally named `f'
136 in the JFFS source code. */
137struct jffs_file
138{
139 __u32 ino; /* Inode number. */
140 __u32 pino; /* Parent's inode number. */
141 __u32 mode; /* file_type, mode */
142 __u16 uid; /* owner */
143 __u16 gid; /* group */
144 __u32 atime; /* Last access time. */
145 __u32 mtime; /* Last modification time. */
146 __u32 ctime; /* Creation time. */
147 __u8 nsize; /* Name length. */
148 __u8 nlink; /* Number of links. */
149 __u8 deleted; /* Has this file been deleted? */
150 char *name; /* The name of this file; NULL-terminated. */
151 __u32 size; /* The total size of the file's data. */
152 __u32 highest_version; /* The highest version number of this file. */
153 struct jffs_control *c;
154 struct jffs_file *parent; /* Reference to the parent directory. */
155 struct jffs_file *children; /* Always NULL for plain files. */
156 struct jffs_file *sibling_prev; /* Siblings in the same directory. */
157 struct jffs_file *sibling_next;
158 struct list_head hash; /* hash list. */
159 struct jffs_node *range_head; /* The final data. */
160 struct jffs_node *range_tail; /* The first data. */
161 struct jffs_node *version_head; /* The youngest node. */
162 struct jffs_node *version_tail; /* The oldest node. */
163};
164
165
166/* This is just a definition of a simple list used for keeping track of
167 files deleted due to a rename. This list is only used during the
168 mounting of the file system and only if there have been rename operations
169 earlier. */
170struct jffs_delete_list
171{
172 __u32 ino;
173 struct jffs_delete_list *next;
174};
175
176
177/* A struct for the overall file system control. Pointers to
178 jffs_control structs are named `c' in the source code. */
179struct jffs_control
180{
181 struct super_block *sb; /* Reference to the VFS super block. */
182 struct jffs_file *root; /* The root directory file. */
183 struct list_head *hash; /* Hash table for finding files by ino. */
184 struct jffs_fmcontrol *fmc; /* Flash memory control structure. */
185 __u32 hash_len; /* The size of the hash table. */
186 __u32 next_ino; /* Next inode number to use for new files. */
187 __u16 building_fs; /* Is the file system being built right now? */
188 struct jffs_delete_list *delete_list; /* Track deleted files. */
189 pid_t thread_pid; /* GC thread's PID */
190 struct task_struct *gc_task; /* GC task struct */
191 struct completion gc_thread_comp; /* GC thread exit mutex */
192 __u32 gc_minfree_threshold; /* GC trigger thresholds */
193 __u32 gc_maxdirty_threshold;
194};
195
196
197/* Used to inform about flash status. */
198struct jffs_flash_status
199{
200 __u32 size;
201 __u32 used;
202 __u32 dirty;
203 __u32 begin;
204 __u32 end;
205};
206
207/* This stuff could be used for finding memory leaks. */
208#define JFFS_MEMORY_DEBUG 0
209
210extern long no_jffs_node;
211#if defined(JFFS_MEMORY_DEBUG) && JFFS_MEMORY_DEBUG
212extern long no_jffs_control;
213extern long no_jffs_raw_inode;
214extern long no_jffs_node_ref;
215extern long no_jffs_fm;
216extern long no_jffs_fmcontrol;
217extern long no_hash;
218extern long no_name;
219#define DJM(x) x
220#else
221#define DJM(x)
222#endif
223
224#endif /* __LINUX_JFFS_H__ */