xref: /freebsd/sys/fs/ext2fs/ext2fs.h (revision f5f7c05209ca2c3748fd8b27c5e80ffad49120eb)
1 /*-
2  *  modified for EXT2FS support in Lites 1.1
3  *
4  *  Aug 1995, Godmar Back (gback@cs.utah.edu)
5  *  University of Utah, Department of Computer Science
6  *
7  * $FreeBSD$
8  */
9 /*-
10  * Copyright (c) 2009 Aditya Sarawgi
11  * All rights reserved.
12  *
13  * Redistribution and use in source and binary forms, with or without
14  * modification, are permitted provided that the following conditions
15  * are met:
16  * 1. Redistributions of source code must retain the above copyright
17  *    notice, this list of conditions and the following disclaimer.
18  * 2. Redistributions in binary form must reproduce the above copyright
19  *    notice, this list of conditions and the following disclaimer in the
20  *    documentation and/or other materials provided with the distribution.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  *
34  *
35  */
36 
37 #ifndef _FS_EXT2FS_EXT2FS_H_
38 #define _FS_EXT2FS_EXT2FS_H_
39 
40 #include <sys/types.h>
41 
42 /*
43  * Maximal count of links to a file
44  */
45 #define EXT2_LINK_MAX		32000
46 
47 /*
48  * A summary of contiguous blocks of various sizes is maintained
49  * in each cylinder group. Normally this is set by the initial
50  * value of fs_maxcontig.
51  *
52  * XXX:FS_MAXCONTIG is set to 16 to conserve space. Here we set
53  * EXT2_MAXCONTIG to 32 for better performance.
54  */
55 #define EXT2_MAXCONTIG		32
56 
57 /*
58  * Constants relative to the data blocks
59  */
60 #define	EXT2_NDIR_BLOCKS		12
61 #define	EXT2_IND_BLOCK			EXT2_NDIR_BLOCKS
62 #define	EXT2_DIND_BLOCK			(EXT2_IND_BLOCK + 1)
63 #define	EXT2_TIND_BLOCK			(EXT2_DIND_BLOCK + 1)
64 #define	EXT2_N_BLOCKS			(EXT2_TIND_BLOCK + 1)
65 #define EXT2_MAXSYMLINKLEN		(EXT2_N_BLOCKS * sizeof(uint32_t))
66 
67 /*
68  * The path name on which the file system is mounted is maintained
69  * in fs_fsmnt. MAXMNTLEN defines the amount of space allocated in
70  * the super block for this name.
71  */
72 #define MAXMNTLEN 512
73 
74 /*
75  * Super block for an ext2fs file system.
76  */
77 struct ext2fs {
78 	uint32_t  e2fs_icount;		/* Inode count */
79 	uint32_t  e2fs_bcount;		/* blocks count */
80 	uint32_t  e2fs_rbcount;		/* reserved blocks count */
81 	uint32_t  e2fs_fbcount;		/* free blocks count */
82 	uint32_t  e2fs_ficount;		/* free inodes count */
83 	uint32_t  e2fs_first_dblock;	/* first data block */
84 	uint32_t  e2fs_log_bsize;	/* block size = 1024*(2^e2fs_log_bsize) */
85 	uint32_t  e2fs_log_fsize;	/* fragment size */
86 	uint32_t  e2fs_bpg;		/* blocks per group */
87 	uint32_t  e2fs_fpg;		/* frags per group */
88 	uint32_t  e2fs_ipg;		/* inodes per group */
89 	uint32_t  e2fs_mtime;		/* mount time */
90 	uint32_t  e2fs_wtime;		/* write time */
91 	uint16_t  e2fs_mnt_count;	/* mount count */
92 	uint16_t  e2fs_max_mnt_count;	/* max mount count */
93 	uint16_t  e2fs_magic;		/* magic number */
94 	uint16_t  e2fs_state;		/* file system state */
95 	uint16_t  e2fs_beh;		/* behavior on errors */
96 	uint16_t  e2fs_minrev;		/* minor revision level */
97 	uint32_t  e2fs_lastfsck;	/* time of last fsck */
98 	uint32_t  e2fs_fsckintv;	/* max time between fscks */
99 	uint32_t  e2fs_creator;		/* creator OS */
100 	uint32_t  e2fs_rev;		/* revision level */
101 	uint16_t  e2fs_ruid;		/* default uid for reserved blocks */
102 	uint16_t  e2fs_rgid;		/* default gid for reserved blocks */
103 	/* EXT2_DYNAMIC_REV superblocks */
104 	uint32_t  e2fs_first_ino;	/* first non-reserved inode */
105 	uint16_t  e2fs_inode_size;	/* size of inode structure */
106 	uint16_t  e2fs_block_group_nr;	/* block grp number of this sblk*/
107 	uint32_t  e2fs_features_compat; /*  compatible feature set */
108 	uint32_t  e2fs_features_incompat; /* incompatible feature set */
109 	uint32_t  e2fs_features_rocompat; /* RO-compatible feature set */
110 	uint8_t	  e2fs_uuid[16];	/* 128-bit uuid for volume */
111 	char      e2fs_vname[16];	/* volume name */
112 	char      e2fs_fsmnt[64]; 	/* name mounted on */
113 	uint32_t  e2fs_algo;		/* For compression */
114 	uint8_t   e2fs_prealloc;	/* # of blocks for old prealloc */
115 	uint8_t   e2fs_dir_prealloc;	/* # of blocks for old prealloc dirs */
116 	uint16_t  e2fs_reserved_ngdb;	/* # of reserved gd blocks for resize */
117 	char      e3fs_journal_uuid[16]; /* uuid of journal superblock */
118 	uint32_t  e3fs_journal_inum;	/* inode number of journal file */
119 	uint32_t  e3fs_journal_dev;	/* device number of journal file */
120 	uint32_t  e3fs_last_orphan;	/* start of list of inodes to delete */
121 	uint32_t  e3fs_hash_seed[4];	/* HTREE hash seed */
122 	char      e3fs_def_hash_version; /* Default hash version to use */
123 	char      e3fs_reserved_char_pad;
124 	uint32_t  e3fs_default_mount_opts;
125 	uint32_t  e3fs_first_meta_bg;	/* First metablock block group */
126 	uint32_t  e3fs_mkfs_time;      /* when the fs was created */
127 	uint32_t  e3fs_jnl_blks[17];   /* backup of the journal inode */
128 	uint32_t  e4fs_bcount_hi;      /* block count */
129 	uint32_t  e4fs_rbcount_hi;     /* reserved blocks count */
130 	uint32_t  e4fs_fbcount_hi;     /* free blocks count */
131 	uint16_t  e4fs_min_extra_isize;/* all inodes have at least some bytes */
132 	uint16_t  e4fs_want_extra_isize; /* inodes must reserve some bytes */
133 	uint32_t  e4fs_flags;	  /* miscellaneous flags */
134 	uint16_t  e4fs_raid_stride;    /* RAID stride */
135 	uint16_t  e4fs_mmpintv;	/* number of seconds to wait in MMP checking */
136 	uint64_t  e4fs_mmpblk;	 /* block for multi-mount protection */
137 	uint32_t  e4fs_raid_stripe_wid;/* blocks on all data disks (N * stride) */
138 	uint8_t   e4fs_log_gpf;	/* FLEX_BG group size */
139 	uint8_t   e4fs_char_pad2;
140 	uint16_t  e4fs_pad;
141 	uint32_t  reserved2[162];	/* Padding to the end of the block */
142 };
143 
144 
145 /*
146  * In-Memory Superblock
147  */
148 
149 struct m_ext2fs {
150 	struct ext2fs * e2fs;
151 	char     e2fs_fsmnt[MAXMNTLEN];/* name mounted on */
152 	char     e2fs_ronly;      /* mounted read-only flag */
153 	char     e2fs_fmod;       /* super block modified flag */
154 	uint32_t e2fs_bsize;      /* Block size */
155 	uint32_t e2fs_bshift;     /* calc of logical block no */
156 	int32_t  e2fs_bpg;	  /* Number of blocks per group */
157 	int64_t  e2fs_qbmask;     /* = s_blocksize -1 */
158 	uint32_t e2fs_fsbtodb;    /* Shift to get disk block */
159 	uint32_t e2fs_ipg;	  /* Number of inodes per group */
160 	uint32_t e2fs_ipb;	  /* Number of inodes per block */
161 	uint32_t e2fs_itpg;       /* Number of inode table per group */
162 	uint32_t e2fs_fsize;      /* Size of fragments per block */
163 	uint32_t e2fs_fpb;	  /* Number of fragments per block */
164 	uint32_t e2fs_fpg;	  /* Number of fragments per group */
165 	uint32_t e2fs_gdbcount;   /* Number of group descriptors */
166 	uint32_t e2fs_gcount;     /* Number of groups */
167 	int32_t  e2fs_isize;      /* Size of inode */
168 	uint32_t e2fs_total_dir;  /* Total number of directories */
169 	uint8_t	*e2fs_contigdirs; /* (u) # of contig. allocated dirs */
170 	char     e2fs_wasvalid;   /* valid at mount time */
171 	off_t    e2fs_maxfilesize;
172 	struct   ext2_gd *e2fs_gd; /* Group Descriptors */
173 	int32_t  e2fs_maxcontig;	/* max number of contiguous blks */
174 	int32_t  e2fs_contigsumsize;    /* size of cluster summary array */
175 	int32_t *e2fs_maxcluster;       /* max cluster in each cyl group */
176 	struct   csum *e2fs_clustersum; /* cluster summary in each cyl group */
177 };
178 
179 /*
180  * The second extended file system version
181  */
182 #define E2FS_DATE		"95/08/09"
183 #define E2FS_VERSION		"0.5b"
184 
185 /*
186  * The second extended file system magic number
187  */
188 #define E2FS_MAGIC		0xEF53
189 
190 /*
191  * Revision levels
192  */
193 #define E2FS_REV0		0	/* The good old (original) format */
194 #define E2FS_REV1		1 	/* V2 format w/ dynamic inode sizes */
195 
196 #define E2FS_CURRENT_REV	E2FS_REV0
197 #define E2FS_MAX_SUPP_REV	E2FS_REV1
198 
199 #define E2FS_REV0_INODE_SIZE 128
200 
201 /*
202  * compatible/incompatible features
203  */
204 #define EXT2F_COMPAT_PREALLOC		0x0001
205 #define EXT2F_COMPAT_HASJOURNAL		0x0004
206 #define EXT2F_COMPAT_RESIZE		0x0010
207 #define EXT2F_COMPAT_DIRHASHINDEX	0x0020
208 
209 #define EXT2F_ROCOMPAT_SPARSESUPER	0x0001
210 #define EXT2F_ROCOMPAT_LARGEFILE	0x0002
211 #define EXT2F_ROCOMPAT_BTREE_DIR	0x0004
212 #define EXT2F_ROCOMPAT_HUGE_FILE	0x0008
213 #define EXT2F_ROCOMPAT_GDT_CSUM		0x0010
214 #define EXT2F_ROCOMPAT_DIR_NLINK	0x0020
215 #define EXT2F_ROCOMPAT_EXTRA_ISIZE	0x0040
216 
217 #define EXT2F_INCOMPAT_COMP		0x0001
218 #define EXT2F_INCOMPAT_FTYPE		0x0002
219 #define EXT2F_INCOMPAT_META_BG		0x0010
220 #define EXT2F_INCOMPAT_EXTENTS		0x0040
221 #define EXT2F_INCOMPAT_64BIT		0x0080
222 #define EXT2F_INCOMPAT_MMP		0x0100
223 #define EXT2F_INCOMPAT_FLEX_BG		0x0200
224 
225 /*
226  * Features supported in this implementation
227  *
228  * We support the following REV1 features:
229  * - EXT2F_ROCOMPAT_SPARSESUPER
230  * - EXT2F_ROCOMPAT_LARGEFILE
231  * - EXT2F_INCOMPAT_FTYPE
232  */
233 #define EXT2F_COMPAT_SUPP		0x0000
234 #define EXT2F_ROCOMPAT_SUPP		(EXT2F_ROCOMPAT_SPARSESUPER | \
235 					 EXT2F_ROCOMPAT_LARGEFILE | \
236 					 EXT2F_ROCOMPAT_EXTRA_ISIZE)
237 #define EXT2F_INCOMPAT_SUPP		EXT2F_INCOMPAT_FTYPE
238 
239 /* Assume that user mode programs are passing in an ext2fs superblock, not
240  * a kernel struct super_block.  This will allow us to call the feature-test
241  * macros from user land. */
242 #define EXT2_SB(sb)	(sb)
243 
244 /*
245  * Feature set definitions
246  */
247 #define EXT2_HAS_COMPAT_FEATURE(sb,mask)			\
248 	( EXT2_SB(sb)->e2fs->e2fs_features_compat & htole32(mask) )
249 #define EXT2_HAS_RO_COMPAT_FEATURE(sb,mask)			\
250 	( EXT2_SB(sb)->e2fs->e2fs_features_rocompat & htole32(mask) )
251 #define EXT2_HAS_INCOMPAT_FEATURE(sb,mask)			\
252 	( EXT2_SB(sb)->e2fs->e2fs_features_incompat & htole32(mask) )
253 
254 /*
255  * Definitions of behavior on errors
256  */
257 #define E2FS_BEH_CONTINUE		1	/* continue operation */
258 #define E2FS_BEH_READONLY		2	/* remount fs read only */
259 #define E2FS_BEH_PANIC			3	/* cause panic */
260 #define E2FS_BEH_DEFAULT		E2FS_BEH_CONTINUE
261 
262 /*
263  * OS identification
264  */
265 #define E2FS_OS_LINUX		0
266 #define E2FS_OS_HURD		1
267 #define E2FS_OS_MASIX		2
268 #define E2FS_OS_FREEBSD		3
269 #define E2FS_OS_LITES		4
270 
271 /*
272  * File clean flags
273  */
274 #define	E2FS_ISCLEAN			0x0001	/* Unmounted cleanly */
275 #define	E2FS_ERRORS			0x0002	/* Errors detected */
276 
277 /* ext2 file system block group descriptor */
278 
279 struct ext2_gd {
280 	uint32_t ext2bgd_b_bitmap;	/* blocks bitmap block */
281 	uint32_t ext2bgd_i_bitmap;	/* inodes bitmap block */
282 	uint32_t ext2bgd_i_tables;	/* inodes table block  */
283 	uint16_t ext2bgd_nbfree;	/* number of free blocks */
284 	uint16_t ext2bgd_nifree;	/* number of free inodes */
285 	uint16_t ext2bgd_ndirs;	/* number of directories */
286 	uint16_t reserved;
287 	uint32_t reserved2[3];
288 };
289 
290 /* cluster summary information */
291 
292 struct csum {
293 	int8_t   cs_init; /* cluster summary has been initialized */
294 	int32_t *cs_sum;  /* cluster summary array */
295 };
296 
297 /* EXT2FS metadatas are stored in little-endian byte order. These macros
298  * helps reading these metadatas
299  */
300 
301 #define e2fs_cgload(old, new, size) memcpy((new), (old), (size));
302 #define e2fs_cgsave(old, new, size) memcpy((new), (old), (size));
303 
304 /*
305  * Macro-instructions used to manage several block sizes
306  */
307 #define EXT2_MIN_BLOCK_SIZE		1024
308 #define	EXT2_MAX_BLOCK_SIZE		4096
309 #define EXT2_MIN_BLOCK_LOG_SIZE		  10
310 #define EXT2_BLOCK_SIZE(s)		((s)->e2fs_bsize)
311 #define	EXT2_ADDR_PER_BLOCK(s)		(EXT2_BLOCK_SIZE(s) / sizeof(uint32_t))
312 #define EXT2_INODE_SIZE(s)		(EXT2_SB(s)->e2fs_isize)
313 
314 /*
315  * Macro-instructions used to manage fragments
316  */
317 #define EXT2_MIN_FRAG_SIZE		1024
318 #define	EXT2_MAX_FRAG_SIZE		4096
319 #define EXT2_MIN_FRAG_LOG_SIZE		  10
320 #define EXT2_FRAG_SIZE(s)		(EXT2_SB(s)->e2fs_fsize)
321 #define EXT2_FRAGS_PER_BLOCK(s)		(EXT2_SB(s)->e2fs_fpb)
322 
323 /*
324  * Macro-instructions used to manage group descriptors
325  */
326 #define EXT2_BLOCKS_PER_GROUP(s)	(EXT2_SB(s)->e2fs_bpg)
327 
328 #endif	/* !_FS_EXT2FS_EXT2FS_H_ */
329