Line data Source code
1 : /* $OpenBSD: ext2fs.h,v 1.23 2016/04/27 11:27:24 krw Exp $ */
2 : /* $NetBSD: ext2fs.h,v 1.10 2000/01/28 16:00:23 bouyer Exp $ */
3 :
4 : /*
5 : * Copyright (c) 1997 Manuel Bouyer.
6 : * Copyright (c) 1982, 1986, 1993
7 : * The Regents of the University of California. All rights reserved.
8 : *
9 : * Redistribution and use in source and binary forms, with or without
10 : * modification, are permitted provided that the following conditions
11 : * are met:
12 : * 1. Redistributions of source code must retain the above copyright
13 : * notice, this list of conditions and the following disclaimer.
14 : * 2. Redistributions in binary form must reproduce the above copyright
15 : * notice, this list of conditions and the following disclaimer in the
16 : * documentation and/or other materials provided with the distribution.
17 : * 3. Neither the name of the University nor the names of its contributors
18 : * may be used to endorse or promote products derived from this software
19 : * without specific prior written permission.
20 : *
21 : * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 : * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 : * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 : * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 : * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 : * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 : * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 : * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 : * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 : * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 : * SUCH DAMAGE.
32 : *
33 : * @(#)fs.h 8.10 (Berkeley) 10/27/94
34 : * Modified for ext2fs by Manuel Bouyer.
35 : */
36 :
37 : #include <sys/endian.h>
38 :
39 : /*
40 : * Each disk drive contains some number of file systems.
41 : * A file system consists of a number of cylinder groups.
42 : * Each cylinder group has inodes and data.
43 : *
44 : * A file system is described by its super-block, which in turn
45 : * describes the cylinder groups. The super-block is critical
46 : * data and is replicated in each cylinder group to protect against
47 : * catastrophic loss. This is done at `newfs' time and the critical
48 : * super-block data does not change, so the copies need not be
49 : * referenced further unless disaster strikes.
50 : *
51 : * The first boot and super blocks are given in absolute disk addresses.
52 : * The byte-offset forms are preferred, as they don't imply a sector size.
53 : */
54 : #define BBSIZE 1024
55 : #define SBSIZE 1024
56 : #define BBOFF ((off_t)(0))
57 : #define SBOFF ((off_t)(BBOFF + BBSIZE))
58 : #define BBLOCK ((daddr_t)(0))
59 : #define SBLOCK ((daddr_t)(BBLOCK + BBSIZE / DEV_BSIZE))
60 :
61 : /*
62 : * Inodes are, like in UFS, 32-bit unsigned integers and therefore ufsino_t.
63 : * Disk blocks are 32-bit, if the filesystem isn't operating in 64-bit mode
64 : * (the incompatible ext4 64BIT flag). More work is needed to properly use
65 : * daddr_t as the disk block data type on both BE and LE architectures.
66 : * XXX disk blocks are simply u_int32_t for now.
67 : */
68 :
69 : /*
70 : * MINBSIZE is the smallest allowable block size.
71 : * MINBSIZE must be big enough to hold a cylinder group block,
72 : * thus changes to (struct cg) must keep its size within MINBSIZE.
73 : * Note that super blocks are always of size SBSIZE,
74 : * and that both SBSIZE and MAXBSIZE must be >= MINBSIZE.
75 : * FSIZE means fragment size.
76 : */
77 : #define LOG_MINBSIZE 10
78 : #define MINBSIZE (1 << LOG_MINBSIZE)
79 : #define LOG_MINFSIZE 10
80 : #define MINFSIZE (1 << LOG_MINFSIZE)
81 :
82 : /*
83 : * The path name on which the file system is mounted is maintained
84 : * in fs_fsmnt. MAXMNTLEN defines the amount of space allocated in
85 : * the super block for this name.
86 : */
87 : #define MAXMNTLEN 512
88 :
89 : /*
90 : * MINFREE gives the minimum acceptable percentage of file system
91 : * blocks which may be free. If the freelist drops below this level
92 : * only the superuser may continue to allocate blocks. This may
93 : * be set to 0 if no reserve of free blocks is deemed necessary,
94 : * however throughput drops by fifty percent if the file system
95 : * is run at between 95% and 100% full; thus the minimum default
96 : * value of fs_minfree is 5%. However, to get good clustering
97 : * performance, 10% is a better choice. hence we use 10% as our
98 : * default value. With 10% free space, fragmentation is not a
99 : * problem, so we choose to optimize for time.
100 : */
101 : #define MINFREE 5
102 :
103 : /*
104 : * Super block for an ext2fs file system.
105 : */
106 : struct ext2fs {
107 : u_int32_t e2fs_icount; /* Inode count */
108 : u_int32_t e2fs_bcount; /* blocks count */
109 : u_int32_t e2fs_rbcount; /* reserved blocks count */
110 : u_int32_t e2fs_fbcount; /* free blocks count */
111 : u_int32_t e2fs_ficount; /* free inodes count */
112 : u_int32_t e2fs_first_dblock; /* first data block */
113 : u_int32_t e2fs_log_bsize; /* block size = 1024*(2^e2fs_log_bsize) */
114 : u_int32_t e2fs_log_fsize; /* fragment size log2 */
115 : u_int32_t e2fs_bpg; /* blocks per group */
116 : u_int32_t e2fs_fpg; /* frags per group */
117 : u_int32_t e2fs_ipg; /* inodes per group */
118 : u_int32_t e2fs_mtime; /* mount time */
119 : u_int32_t e2fs_wtime; /* write time */
120 : u_int16_t e2fs_mnt_count; /* mount count */
121 : u_int16_t e2fs_max_mnt_count; /* max mount count */
122 : u_int16_t e2fs_magic; /* magic number */
123 : u_int16_t e2fs_state; /* file system state */
124 : u_int16_t e2fs_beh; /* behavior on errors */
125 : u_int16_t e2fs_minrev; /* minor revision level */
126 : u_int32_t e2fs_lastfsck; /* time of last fsck */
127 : u_int32_t e2fs_fsckintv; /* max time between fscks */
128 : u_int32_t e2fs_creator; /* creator OS */
129 : u_int32_t e2fs_rev; /* revision level */
130 : u_int16_t e2fs_ruid; /* default uid for reserved blocks */
131 : u_int16_t e2fs_rgid; /* default gid for reserved blocks */
132 : /* EXT2_DYNAMIC_REV superblocks */
133 : u_int32_t e2fs_first_ino; /* first non-reserved inode */
134 : u_int16_t e2fs_inode_size; /* size of inode structure */
135 : u_int16_t e2fs_block_group_nr; /* block grp number of this sblk*/
136 : u_int32_t e2fs_features_compat; /* compatible feature set */
137 : u_int32_t e2fs_features_incompat; /* incompatible feature set */
138 : u_int32_t e2fs_features_rocompat; /* RO-compatible feature set */
139 : u_int8_t e2fs_uuid[16]; /* 128-bit uuid for volume */
140 : char e2fs_vname[16]; /* volume name */
141 : char e2fs_fsmnt[64]; /* name mounted on */
142 : u_int32_t e2fs_algo; /* For compression */
143 : u_int8_t e2fs_prealloc; /* # of blocks to preallocate */
144 : u_int8_t e2fs_dir_prealloc; /* # of blocks to preallocate for dir */
145 : u_int16_t e2fs_reserved_ngdb; /* # of reserved gd blocks for resize */
146 : /* Ext3 JBD2 journaling. */
147 : u_int8_t e2fs_journal_uuid[16];
148 : u_int32_t e2fs_journal_ino;
149 : u_int32_t e2fs_journal_dev;
150 : u_int32_t e2fs_last_orphan; /* start of list of inodes to delete */
151 : u_int32_t e2fs_hash_seed[4]; /* htree hash seed */
152 : u_int8_t e2fs_def_hash_version;
153 : u_int8_t e2fs_journal_backup_type;
154 : u_int16_t e2fs_gdesc_size;
155 : u_int32_t e2fs_default_mount_opts;
156 : u_int32_t e2fs_first_meta_bg;
157 : u_int32_t e2fs_mkfs_time;
158 : u_int32_t e2fs_journal_backup[17];
159 : u_int32_t reserved2[172];
160 : };
161 :
162 :
163 : /* in-memory data for ext2fs */
164 : struct m_ext2fs {
165 : struct ext2fs e2fs;
166 : u_char e2fs_fsmnt[MAXMNTLEN]; /* name mounted on */
167 : int8_t e2fs_ronly; /* mounted read-only flag */
168 : int8_t e2fs_fmod; /* super block modified flag */
169 : int32_t e2fs_fsize; /* fragment size */
170 : int32_t e2fs_bsize; /* block size */
171 : int32_t e2fs_bshift; /* ``lblkno'' calc of logical blkno */
172 : int32_t e2fs_bmask; /* ``blkoff'' calc of blk offsets */
173 : int64_t e2fs_qbmask; /* ~fs_bmask - for use with quad size */
174 : int32_t e2fs_fsbtodb; /* fsbtodb and dbtofsb shift constant */
175 : int32_t e2fs_ncg; /* number of cylinder groups */
176 : int32_t e2fs_ngdb; /* number of group descriptor block */
177 : int32_t e2fs_ipb; /* number of inodes per block */
178 : int32_t e2fs_itpg; /* number of inode table per group */
179 : off_t e2fs_maxfilesize; /* depends on LARGE/HUGE flags */
180 : struct ext2_gd *e2fs_gd; /* group descriptors */
181 : };
182 :
183 : static inline int
184 0 : e2fs_overflow(struct m_ext2fs *fs, off_t lower, off_t value)
185 : {
186 0 : return (value < lower || value > fs->e2fs_maxfilesize);
187 : }
188 :
189 : /*
190 : * Filesystem identification
191 : */
192 : #define E2FS_MAGIC 0xef53 /* the ext2fs magic number */
193 : #define E2FS_REV0 0 /* revision levels */
194 : #define E2FS_REV1 1 /* revision levels */
195 :
196 : /* compatible/imcompatible features */
197 : #define EXT2F_COMPAT_PREALLOC 0x0001
198 : #define EXT2F_COMPAT_HASJOURNAL 0x0004
199 : #define EXT2F_COMPAT_RESIZE 0x0010
200 : #define EXT2F_COMPAT_DIRHASHINDEX 0x0020
201 :
202 :
203 : #define EXT2F_ROCOMPAT_SPARSESUPER 0x0001
204 : #define EXT2F_ROCOMPAT_LARGEFILE 0x0002
205 : #define EXT2F_ROCOMPAT_BTREE_DIR 0x0004
206 : #define EXT2F_ROCOMPAT_HUGE_FILE 0x0008
207 :
208 : #define EXT2F_INCOMPAT_COMP 0x0001
209 : #define EXT2F_INCOMPAT_FTYPE 0x0002
210 : #define EXT2F_INCOMPAT_RECOVER 0x0004
211 : #define EXT2F_INCOMPAT_JOURNAL_DEV 0x0008
212 : #define EXT2F_INCOMPAT_META_BG 0x0010
213 : #define EXT2F_INCOMPAT_EXTENTS 0x0040
214 : #define EXT2F_INCOMPAT_FLEX_BG 0x0200
215 :
216 : /* features supported in this implementation */
217 : #define EXT2F_COMPAT_SUPP 0x0000
218 : #define EXT2F_ROCOMPAT_SUPP (EXT2F_ROCOMPAT_SPARSESUPER | \
219 : EXT2F_ROCOMPAT_LARGEFILE)
220 : #define EXT2F_INCOMPAT_SUPP (EXT2F_INCOMPAT_FTYPE)
221 : #define EXT4F_RO_INCOMPAT_SUPP (EXT2F_INCOMPAT_EXTENTS | \
222 : EXT2F_INCOMPAT_FLEX_BG | \
223 : EXT2F_INCOMPAT_META_BG | \
224 : EXT2F_INCOMPAT_RECOVER)
225 :
226 : /*
227 : * Definitions of behavior on errors
228 : */
229 : #define E2FS_BEH_CONTINUE 1 /* continue operation */
230 : #define E2FS_BEH_READONLY 2 /* remount fs read only */
231 : #define E2FS_BEH_PANIC 3 /* cause panic */
232 : #define E2FS_BEH_DEFAULT E2FS_BEH_CONTINUE
233 :
234 : /*
235 : * OS identification
236 : */
237 : #define E2FS_OS_LINUX 0
238 : #define E2FS_OS_HURD 1
239 : #define E2FS_OS_MASIX 2
240 :
241 : /*
242 : * Filesystem clean flags
243 : */
244 : #define E2FS_ISCLEAN 0x01
245 : #define E2FS_ERRORS 0x02
246 :
247 : /* ext2 file system block group descriptor */
248 :
249 : struct ext2_gd {
250 : u_int32_t ext2bgd_b_bitmap; /* blocks bitmap block */
251 : u_int32_t ext2bgd_i_bitmap; /* inodes bitmap block */
252 : u_int32_t ext2bgd_i_tables; /* inodes table block */
253 : u_int16_t ext2bgd_nbfree; /* number of free blocks */
254 : u_int16_t ext2bgd_nifree; /* number of free inodes */
255 : u_int16_t ext2bgd_ndirs; /* number of directories */
256 : u_int16_t reserved;
257 : u_int32_t reserved2[3];
258 : };
259 :
260 : /*
261 : * If the EXT2F_ROCOMPAT_SPARSESUPER flag is set, the cylinder group has a
262 : * copy of the super and cylinder group descriptors blocks only if it's
263 : * a power of 3, 5 or 7
264 : */
265 :
266 : static __inline__ int cg_has_sb(int) __attribute__((__unused__));
267 : static __inline int
268 0 : cg_has_sb(i)
269 : int i;
270 : {
271 : int a3 ,a5 , a7;
272 :
273 0 : if (i == 0 || i == 1)
274 0 : return 1;
275 0 : for (a3 = 3, a5 = 5, a7 = 7;
276 0 : a3 <= i || a5 <= i || a7 <= i;
277 0 : a3 *= 3, a5 *= 5, a7 *= 7)
278 0 : if (i == a3 || i == a5 || i == a7)
279 0 : return 1;
280 0 : return 0;
281 0 : }
282 :
283 : /*
284 : * Ext2 metadata is stored in little-endian byte order.
285 : * JBD2 journal used in ext3 and ext4 is big-endian!
286 : */
287 : #if BYTE_ORDER == LITTLE_ENDIAN
288 : #define e2fs_sbload(old, new) memcpy((new), (old), SBSIZE);
289 : #define e2fs_cgload(old, new, size) memcpy((new), (old), (size));
290 : #define e2fs_sbsave(old, new) memcpy((new), (old), SBSIZE);
291 : #define e2fs_cgsave(old, new, size) memcpy((new), (old), (size));
292 : #else
293 : void e2fs_sb_bswap(struct ext2fs *, struct ext2fs *);
294 : void e2fs_cg_bswap(struct ext2_gd *, struct ext2_gd *, int);
295 : #define e2fs_sbload(old, new) e2fs_sb_bswap((old), (new))
296 : #define e2fs_cgload(old, new, size) e2fs_cg_bswap((old), (new), (size));
297 : #define e2fs_sbsave(old, new) e2fs_sb_bswap((old), (new))
298 : #define e2fs_cgsave(old, new, size) e2fs_cg_bswap((old), (new), (size));
299 : #endif
300 :
301 : /*
302 : * Turn file system block numbers into disk block addresses.
303 : * This maps file system blocks to device size blocks.
304 : */
305 : #define fsbtodb(fs, b) ((b) << (fs)->e2fs_fsbtodb)
306 : #define dbtofsb(fs, b) ((b) >> (fs)->e2fs_fsbtodb)
307 :
308 : /*
309 : * Macros for handling inode numbers:
310 : * inode number to file system block offset.
311 : * inode number to cylinder group number.
312 : * inode number to file system block address.
313 : */
314 : #define ino_to_cg(fs, x) (((x) - 1) / (fs)->e2fs.e2fs_ipg)
315 : #define ino_to_fsba(fs, x) \
316 : ((fs)->e2fs_gd[ino_to_cg(fs, x)].ext2bgd_i_tables + \
317 : (((x)-1) % (fs)->e2fs.e2fs_ipg)/(fs)->e2fs_ipb)
318 : #define ino_to_fsbo(fs, x) (((x)-1) % (fs)->e2fs_ipb)
319 :
320 : /*
321 : * Give cylinder group number for a file system block.
322 : * Give cylinder group block number for a file system block.
323 : */
324 : #define dtog(fs, d) (((d) - (fs)->e2fs.e2fs_first_dblock) / (fs)->e2fs.e2fs_fpg)
325 : #define dtogd(fs, d) \
326 : (((d) - (fs)->e2fs.e2fs_first_dblock) % (fs)->e2fs.e2fs_fpg)
327 :
328 : /*
329 : * The following macros optimize certain frequently calculated
330 : * quantities by using shifts and masks in place of divisions
331 : * modulos and multiplications.
332 : */
333 : #define blkoff(fs, loc) /* calculates (loc % fs->e2fs_bsize) */ \
334 : ((loc) & (fs)->e2fs_qbmask)
335 : #define lblktosize(fs, blk) /* calculates (blk * fs->e2fs_bsize) */ \
336 : ((blk) << (fs)->e2fs_bshift)
337 : #define lblkno(fs, loc) /* calculates (loc / fs->e2fs_bsize) */ \
338 : ((loc) >> (fs)->e2fs_bshift)
339 : #define blkroundup(fs, size) /* calculates roundup(size, fs->e2fs_bsize) */ \
340 : (((size) + (fs)->e2fs_qbmask) & (fs)->e2fs_bmask)
341 : #define fragroundup(fs, size) /* calculates roundup(size, fs->e2fs_bsize) */ \
342 : (((size) + (fs)->e2fs_qbmask) & (fs)->e2fs_bmask)
343 : /*
344 : * Determine the number of available frags given a
345 : * percentage to hold in reserve.
346 : */
347 : #define freespace(fs) \
348 : ((fs)->e2fs.e2fs_fbcount - (fs)->e2fs.e2fs_rbcount)
349 :
350 : /*
351 : * Number of indirects in a file system block.
352 : */
353 : #define NINDIR(fs) ((fs)->e2fs_bsize / sizeof(u_int32_t))
|
