xref: /freebsd/sys/ufs/ffs/fs.h (revision 09e8dea79366f1e5b3a73e8a271b26e4b6bf2e6a)
1 /*
2  * Copyright (c) 1982, 1986, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. 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	8.13 (Berkeley) 3/21/95
34  * $FreeBSD$
35  */
36 
37 #ifndef _UFS_FFS_FS_H_
38 #define _UFS_FFS_FS_H_
39 
40 /*
41  * Each disk drive contains some number of filesystems.
42  * A filesystem consists of a number of cylinder groups.
43  * Each cylinder group has inodes and data.
44  *
45  * A filesystem is described by its super-block, which in turn
46  * describes the cylinder groups.  The super-block is critical
47  * data and is replicated in each cylinder group to protect against
48  * catastrophic loss.  This is done at `newfs' time and the critical
49  * super-block data does not change, so the copies need not be
50  * referenced further unless disaster strikes.
51  *
52  * For filesystem fs, the offsets of the various blocks of interest
53  * are given in the super block as:
54  *	[fs->fs_sblkno]		Super-block
55  *	[fs->fs_cblkno]		Cylinder group block
56  *	[fs->fs_iblkno]		Inode blocks
57  *	[fs->fs_dblkno]		Data blocks
58  * The beginning of cylinder group cg in fs, is given by
59  * the ``cgbase(fs, cg)'' macro.
60  *
61  * Depending on the architecture and the media, the superblock may
62  * reside in any one of four places. For tiny media where every block
63  * counts, it is placed at the very front of the partition. Historically,
64  * UFS1 placed it 8K from the front to leave room for the disk label and
65  * a small bootstrap. For UFS2 it got moved to 64K from the front to leave
66  * room for the disk label and a bigger bootstrap, and for really piggy
67  * systems we check at 256K from the front if the first three fail. In
68  * all cases the size of the superblock will be SBLOCKSIZE. All values are
69  * given in byte-offset form, so they do not imply a sector size. The
70  * SBLOCKSEARCH specifies the order in which the locations should be searched.
71  */
72 #define SBLOCK_FLOPPY	     0
73 #define SBLOCK_UFS1	  8192
74 #define SBLOCK_UFS2	 65536
75 #define SBLOCK_PIGGY	262144
76 #define SBLOCKSIZE	  8192
77 #define SBLOCKSEARCH \
78 	{ SBLOCK_UFS2, SBLOCK_UFS1, SBLOCK_FLOPPY, SBLOCK_PIGGY, -1 }
79 
80 /*
81  * Max number of fragments per block. This value is NOT tweakable.
82  */
83 #define MAXFRAG 	8
84 
85 /*
86  * Addresses stored in inodes are capable of addressing fragments
87  * of `blocks'. File system blocks of at most size MAXBSIZE can
88  * be optionally broken into 2, 4, or 8 pieces, each of which is
89  * addressable; these pieces may be DEV_BSIZE, or some multiple of
90  * a DEV_BSIZE unit.
91  *
92  * Large files consist of exclusively large data blocks.  To avoid
93  * undue wasted disk space, the last data block of a small file may be
94  * allocated as only as many fragments of a large block as are
95  * necessary.  The filesystem format retains only a single pointer
96  * to such a fragment, which is a piece of a single large block that
97  * has been divided.  The size of such a fragment is determinable from
98  * information in the inode, using the ``blksize(fs, ip, lbn)'' macro.
99  *
100  * The filesystem records space availability at the fragment level;
101  * to determine block availability, aligned fragments are examined.
102  */
103 
104 /*
105  * MINBSIZE is the smallest allowable block size.
106  * In order to insure that it is possible to create files of size
107  * 2^32 with only two levels of indirection, MINBSIZE is set to 4096.
108  * MINBSIZE must be big enough to hold a cylinder group block,
109  * thus changes to (struct cg) must keep its size within MINBSIZE.
110  * Note that super blocks are always of size SBSIZE,
111  * and that both SBSIZE and MAXBSIZE must be >= MINBSIZE.
112  */
113 #define MINBSIZE	4096
114 
115 /*
116  * The path name on which the filesystem is mounted is maintained
117  * in fs_fsmnt. MAXMNTLEN defines the amount of space allocated in
118  * the super block for this name.
119  */
120 #define MAXMNTLEN	512
121 
122 /*
123  * There is a 128-byte region in the superblock reserved for in-core
124  * pointers to summary information. Originally this included an array
125  * of pointers to blocks of struct csum; now there are just a few
126  * pointers and the remaining space is padded with fs_ocsp[].
127  *
128  * NOCSPTRS determines the size of this padding. One pointer (fs_csp)
129  * is taken away to point to a contiguous array of struct csum for
130  * all cylinder groups; a second (fs_maxcluster) points to an array
131  * of cluster sizes that is computed as cylinder groups are inspected,
132  * and the third points to an array that tracks the creation of new
133  * directories. A fourth pointer, fs_active, is used when creating
134  * snapshots; it points to a bitmap of cylinder groups for which the
135  * free-block bitmap has changed since the snapshot operation began.
136  */
137 #define	NOCSPTRS	((128 / sizeof(void *)) - 4)
138 
139 /*
140  * A summary of contiguous blocks of various sizes is maintained
141  * in each cylinder group. Normally this is set by the initial
142  * value of fs_maxcontig. To conserve space, a maximum summary size
143  * is set by FS_MAXCONTIG.
144  */
145 #define FS_MAXCONTIG	16
146 
147 /*
148  * MINFREE gives the minimum acceptable percentage of filesystem
149  * blocks which may be free. If the freelist drops below this level
150  * only the superuser may continue to allocate blocks. This may
151  * be set to 0 if no reserve of free blocks is deemed necessary,
152  * however throughput drops by fifty percent if the filesystem
153  * is run at between 95% and 100% full; thus the minimum default
154  * value of fs_minfree is 5%. However, to get good clustering
155  * performance, 10% is a better choice. hence we use 10% as our
156  * default value. With 10% free space, fragmentation is not a
157  * problem, so we choose to optimize for time.
158  */
159 #define MINFREE		8
160 #define DEFAULTOPT	FS_OPTTIME
161 
162 /*
163  * Grigoriy Orlov <gluk@ptci.ru> has done some extensive work to fine
164  * tune the layout preferences for directories within a filesystem.
165  * His algorithm can be tuned by adjusting the following parameters
166  * which tell the system the average file size and the average number
167  * of files per directory. These defaults are well selected for typical
168  * filesystems, but may need to be tuned for odd cases like filesystems
169  * being used for sqiud caches or news spools.
170  */
171 #define AVFILESIZ	16384	/* expected average file size */
172 #define AFPDIR		64	/* expected number of files per directory */
173 
174 /*
175  * The maximum number of snapshot nodes that can be associated
176  * with each filesystem. This limit affects only the number of
177  * snapshot files that can be recorded within the superblock so
178  * that they can be found when the filesystem is mounted. However,
179  * maintaining too many will slow the filesystem performance, so
180  * having this limit is a good idea.
181  */
182 #define FSMAXSNAP 20
183 
184 /*
185  * Used to identify special blocks in snapshots:
186  *
187  * BLK_NOCOPY - A block that was unallocated at the time the snapshot
188  *	was taken, hence does not need to be copied when written.
189  * BLK_SNAP - A block held by another snapshot that is not needed by this
190  *	snapshot. When the other snapshot is freed, the BLK_SNAP entries
191  *	are converted to BLK_NOCOPY. These are needed to allow fsck to
192  *	identify blocks that are in use by other snapshots (which are
193  *	expunged from this snapshot).
194  */
195 #define BLK_NOCOPY ((ufs2_daddr_t)(1))
196 #define BLK_SNAP ((ufs2_daddr_t)(2))
197 
198 /*
199  * Sysctl values for the fast filesystem.
200  */
201 #define	FFS_ADJ_REFCNT		 1	/* adjust inode reference count */
202 #define	FFS_ADJ_BLKCNT		 2	/* adjust inode used block count */
203 #define	FFS_BLK_FREE		 3	/* free range of blocks in map */
204 #define	FFS_DIR_FREE		 4	/* free specified dir inodes in map */
205 #define	FFS_FILE_FREE		 5	/* free specified file inodes in map */
206 #define	FFS_SET_FLAGS		 6	/* set filesystem flags */
207 #define	FFS_MAXID		 7	/* number of valid ffs ids */
208 
209 /*
210  * Command structure passed in to the filesystem to adjust filesystem values.
211  */
212 #define	FFS_CMD_VERSION		0x19790518	/* version ID */
213 struct fsck_cmd {
214 	int32_t	version;	/* version of command structure */
215 	int32_t	handle;		/* reference to filesystem to be changed */
216 	int64_t	value;		/* inode or block number to be affected */
217 	int64_t	size;		/* amount or range to be adjusted */
218 	int64_t	spare;		/* reserved for future use */
219 };
220 
221 /*
222  * Per cylinder group information; summarized in blocks allocated
223  * from first cylinder group data blocks.  These blocks have to be
224  * read in from fs_csaddr (size fs_cssize) in addition to the
225  * super block.
226  */
227 struct csum {
228 	int32_t	cs_ndir;		/* number of directories */
229 	int32_t	cs_nbfree;		/* number of free blocks */
230 	int32_t	cs_nifree;		/* number of free inodes */
231 	int32_t	cs_nffree;		/* number of free frags */
232 };
233 struct csum_total {
234 	int64_t	cs_ndir;		/* number of directories */
235 	int64_t	cs_nbfree;		/* number of free blocks */
236 	int64_t	cs_nifree;		/* number of free inodes */
237 	int64_t	cs_nffree;		/* number of free frags */
238 	int64_t	cs_numclusters;		/* number of free clusters */
239 	int64_t	cs_spare[3];		/* future expansion */
240 };
241 
242 /*
243  * Super block for an FFS filesystem.
244  */
245 struct fs {
246 	int32_t	 fs_firstfield;		/* historic filesystem linked list, */
247 	int32_t	 fs_unused_1;		/*     used for incore super blocks */
248 	int32_t	 fs_sblkno;		/* offset of super-block in filesys */
249 	int32_t	 fs_cblkno;		/* offset of cyl-block in filesys */
250 	int32_t	 fs_iblkno;		/* offset of inode-blocks in filesys */
251 	int32_t	 fs_dblkno;		/* offset of first data after cg */
252 	int32_t	 fs_old_cgoffset;	/* cylinder group offset in cylinder */
253 	int32_t	 fs_old_cgmask;		/* used to calc mod fs_ntrak */
254 	int32_t  fs_old_time;		/* last time written */
255 	int32_t	 fs_old_size;		/* number of blocks in fs */
256 	int32_t	 fs_old_dsize;		/* number of data blocks in fs */
257 	int32_t	 fs_ncg;		/* number of cylinder groups */
258 	int32_t	 fs_bsize;		/* size of basic blocks in fs */
259 	int32_t	 fs_fsize;		/* size of frag blocks in fs */
260 	int32_t	 fs_frag;		/* number of frags in a block in fs */
261 /* these are configuration parameters */
262 	int32_t	 fs_minfree;		/* minimum percentage of free blocks */
263 	int32_t	 fs_old_rotdelay;	/* num of ms for optimal next block */
264 	int32_t	 fs_old_rps;		/* disk revolutions per second */
265 /* these fields can be computed from the others */
266 	int32_t	 fs_bmask;		/* ``blkoff'' calc of blk offsets */
267 	int32_t	 fs_fmask;		/* ``fragoff'' calc of frag offsets */
268 	int32_t	 fs_bshift;		/* ``lblkno'' calc of logical blkno */
269 	int32_t	 fs_fshift;		/* ``numfrags'' calc number of frags */
270 /* these are configuration parameters */
271 	int32_t	 fs_maxcontig;		/* max number of contiguous blks */
272 	int32_t	 fs_maxbpg;		/* max number of blks per cyl group */
273 /* these fields can be computed from the others */
274 	int32_t	 fs_fragshift;		/* block to frag shift */
275 	int32_t	 fs_fsbtodb;		/* fsbtodb and dbtofsb shift constant */
276 	int32_t	 fs_sbsize;		/* actual size of super block */
277 	int32_t	 fs_spare1[2];		/* old fs_csmask */
278 					/* old fs_csshift */
279 	int32_t	 fs_nindir;		/* value of NINDIR */
280 	int32_t	 fs_inopb;		/* value of INOPB */
281 	int32_t	 fs_old_nspf;		/* value of NSPF */
282 /* yet another configuration parameter */
283 	int32_t	 fs_optim;		/* optimization preference, see below */
284 	int32_t	 fs_old_npsect;		/* # sectors/track including spares */
285 	int32_t	 fs_old_interleave;	/* hardware sector interleave */
286 	int32_t	 fs_old_trackskew;	/* sector 0 skew, per track */
287 	int32_t	 fs_id[2];		/* unique filesystem id */
288 /* sizes determined by number of cylinder groups and their sizes */
289 	int32_t	 fs_old_csaddr;		/* blk addr of cyl grp summary area */
290 	int32_t	 fs_cssize;		/* size of cyl grp summary area */
291 	int32_t	 fs_cgsize;		/* cylinder group size */
292 	int32_t	 fs_spare2;		/* old fs_ntrak */
293 	int32_t	 fs_old_nsect;		/* sectors per track */
294 	int32_t  fs_old_spc;		/* sectors per cylinder */
295 	int32_t	 fs_old_ncyl;		/* cylinders in filesystem */
296 	int32_t	 fs_old_cpg;		/* cylinders per group */
297 	int32_t	 fs_ipg;		/* inodes per group */
298 	int32_t	 fs_fpg;		/* blocks per group * fs_frag */
299 /* this data must be re-computed after crashes */
300 	struct	csum fs_old_cstotal;	/* cylinder summary information */
301 /* these fields are cleared at mount time */
302 	int8_t   fs_fmod;		/* super block modified flag */
303 	int8_t   fs_clean;		/* filesystem is clean flag */
304 	int8_t 	 fs_ronly;		/* mounted read-only flag */
305 	int8_t   fs_flags;		/* see FS_ flags below */
306 	u_char	 fs_fsmnt[MAXMNTLEN];	/* name mounted on */
307 /* these fields retain the current block allocation info */
308 	int32_t	 fs_cgrotor;		/* last cg searched */
309 	void 	*fs_ocsp[NOCSPTRS];	/* padding; was list of fs_cs buffers */
310 	u_int8_t *fs_contigdirs;	/* # of contiguously allocated dirs */
311 	struct	csum *fs_csp;		/* cg summary info buffer for fs_cs */
312 	int32_t	*fs_maxcluster;		/* max cluster in each cyl group */
313 	u_int	*fs_active;		/* used by snapshots to track fs */
314 	int32_t	 fs_old_cpc;		/* cyl per cycle in postbl */
315 	int32_t	 fs_maxbsize;		/* maximum blocking factor permitted */
316 	int64_t	 fs_sparecon64[17];	/* old rotation block list head */
317 	int64_t	 fs_sblockloc;		/* location of standard superblock */
318 	struct	csum_total fs_cstotal;	/* cylinder summary information */
319 	ufs_time_t fs_time;		/* last time written */
320 	int64_t	 fs_size;		/* number of blocks in fs */
321 	int64_t	 fs_dsize;		/* number of data blocks in fs */
322 	ufs2_daddr_t fs_csaddr;		/* blk addr of cyl grp summary area */
323 	int64_t	 fs_pendingblocks;	/* blocks in process of being freed */
324 	int32_t	 fs_pendinginodes;	/* inodes in process of being freed */
325 	int32_t	 fs_snapinum[FSMAXSNAP];/* list of snapshot inode numbers */
326 	int32_t	 fs_avgfilesize;	/* expected average file size */
327 	int32_t	 fs_avgfpdir;		/* expected # of files per directory */
328 	int32_t	 fs_save_cgsize;	/* save real cg size to use fs_bsize */
329 	int32_t	 fs_sparecon32[27];	/* reserved for future constants */
330 	int32_t	 fs_contigsumsize;	/* size of cluster summary array */
331 	int32_t	 fs_maxsymlinklen;	/* max length of an internal symlink */
332 	int32_t	 fs_old_inodefmt;	/* format of on-disk inodes */
333 	u_int64_t fs_maxfilesize;	/* maximum representable file size */
334 	int64_t	 fs_qbmask;		/* ~fs_bmask for use with 64-bit size */
335 	int64_t	 fs_qfmask;		/* ~fs_fmask for use with 64-bit size */
336 	int32_t	 fs_state;		/* validate fs_clean field */
337 	int32_t	 fs_old_postblformat;	/* format of positional layout tables */
338 	int32_t	 fs_old_nrpos;		/* number of rotational positions */
339 	int32_t	 fs_spare5[2];		/* old fs_postbloff */
340 					/* old fs_rotbloff */
341 	int32_t	 fs_magic;		/* magic number */
342 };
343 
344 /*
345  * Filesystem identification
346  */
347 #define	FS_UFS1_MAGIC	0x011954	/* UFS1 fast filesystem magic number */
348 #define	FS_UFS2_MAGIC	0x19540119	/* UFS2 fast filesystem magic number */
349 #define	FS_OKAY		0x7c269d38	/* superblock checksum */
350 #define FS_42INODEFMT	-1		/* 4.2BSD inode format */
351 #define FS_44INODEFMT	2		/* 4.4BSD inode format */
352 
353 /*
354  * Preference for optimization.
355  */
356 #define FS_OPTTIME	0	/* minimize allocation time */
357 #define FS_OPTSPACE	1	/* minimize disk fragmentation */
358 
359 /*
360  * Filesystem flags.
361  *
362  * The FS_UNCLEAN flag is set by the kernel when the filesystem was
363  * mounted with fs_clean set to zero. The FS_DOSOFTDEP flag indicates
364  * that the filesystem should be managed by the soft updates code.
365  * Note that the FS_NEEDSFSCK flag is set and cleared only by the
366  * fsck utility. It is set when background fsck finds an unexpected
367  * inconsistency which requires a traditional foreground fsck to be
368  * run. Such inconsistencies should only be found after an uncorrectable
369  * disk error. A foreground fsck will clear the FS_NEEDSFSCK flag when
370  * it has successfully cleaned up the filesystem. The kernel uses this
371  * flag to enforce that inconsistent filesystems be mounted read-only.
372  * The FS_INDEXDIRS flag when set indicates that the kernel maintains
373  * on-disk auxiliary indexes (such as B-trees) for speeding directory
374  * accesses. Kernels that do not support auxiliary indicies clear the
375  * flag to indicate that the indicies need to be rebuilt (by fsck) before
376  * they can be used.
377  */
378 #define FS_UNCLEAN    0x01	/* filesystem not clean at mount */
379 #define FS_DOSOFTDEP  0x02	/* filesystem using soft dependencies */
380 #define FS_NEEDSFSCK  0x04	/* filesystem needs sync fsck before mount */
381 #define FS_INDEXDIRS  0x08	/* kernel supports indexed directories */
382 
383 /*
384  * Macros to access bits in the fs_active array.
385  */
386 #define	ACTIVECGNUM(fs, cg)	((fs)->fs_active[(cg) / (NBBY * sizeof(int))])
387 #define	ACTIVECGOFF(cg)		(1 << ((cg) % (NBBY * sizeof(int))))
388 
389 /*
390  * The size of a cylinder group is calculated by CGSIZE. The maximum size
391  * is limited by the fact that cylinder groups are at most one block.
392  * Its size is derived from the size of the maps maintained in the
393  * cylinder group and the (struct cg) size.
394  */
395 #define CGSIZE(fs) \
396     /* base cg */	(sizeof(struct cg) + sizeof(int32_t) + \
397     /* old btotoff */	(fs)->fs_old_cpg * sizeof(int32_t) + \
398     /* old boff */	(fs)->fs_old_cpg * sizeof(u_int16_t) + \
399     /* inode map */	howmany((fs)->fs_ipg, NBBY) + \
400     /* block map */	howmany((fs)->fs_fpg, NBBY) +\
401     /* if present */	((fs)->fs_contigsumsize <= 0 ? 0 : \
402     /* cluster sum */	(fs)->fs_contigsumsize * sizeof(int32_t) + \
403     /* cluster map */	howmany(fragstoblks(fs, (fs)->fs_fpg), NBBY)))
404 
405 /*
406  * The minimal number of cylinder groups that should be created.
407  */
408 #define MINCYLGRPS	4
409 
410 /*
411  * Convert cylinder group to base address of its global summary info.
412  */
413 #define fs_cs(fs, indx) fs_csp[indx]
414 
415 /*
416  * Cylinder group block for a filesystem.
417  */
418 #define	CG_MAGIC	0x090255
419 struct cg {
420 	int32_t	 cg_firstfield;		/* historic cyl groups linked list */
421 	int32_t	 cg_magic;		/* magic number */
422 	int32_t  cg_old_time;		/* time last written */
423 	int32_t	 cg_cgx;		/* we are the cgx'th cylinder group */
424 	int16_t	 cg_old_ncyl;		/* number of cyl's this cg */
425 	int16_t  cg_old_niblk;		/* number of inode blocks this cg */
426 	int32_t	 cg_ndblk;		/* number of data blocks this cg */
427 	struct	csum cg_cs;		/* cylinder summary information */
428 	int32_t	 cg_rotor;		/* position of last used block */
429 	int32_t	 cg_frotor;		/* position of last used frag */
430 	int32_t	 cg_irotor;		/* position of last used inode */
431 	int32_t	 cg_frsum[MAXFRAG];	/* counts of available frags */
432 	int32_t	 cg_old_btotoff;	/* (int32) block totals per cylinder */
433 	int32_t	 cg_old_boff;		/* (u_int16) free block positions */
434 	int32_t	 cg_iusedoff;		/* (u_int8) used inode map */
435 	int32_t	 cg_freeoff;		/* (u_int8) free block map */
436 	int32_t	 cg_nextfreeoff;	/* (u_int8) next available space */
437 	int32_t	 cg_clustersumoff;	/* (u_int32) counts of avail clusters */
438 	int32_t	 cg_clusteroff;		/* (u_int8) free cluster map */
439 	int32_t	 cg_nclusterblks;	/* number of clusters this cg */
440 	int32_t  cg_niblk;		/* number of inode blocks this cg */
441 	int32_t	 cg_initediblk;		/* last initialized inode */
442 	int32_t	 cg_sparecon32[3];	/* reserved for future use */
443 	ufs_time_t cg_time;		/* time last written */
444 	int64_t	 cg_sparecon64[3];	/* reserved for future use */
445 	u_int8_t cg_space[1];		/* space for cylinder group maps */
446 /* actually longer */
447 };
448 
449 /*
450  * Macros for access to cylinder group array structures
451  */
452 #define cg_chkmagic(cgp) ((cgp)->cg_magic == CG_MAGIC)
453 #define cg_inosused(cgp) \
454     ((u_int8_t *)((u_int8_t *)(cgp) + (cgp)->cg_iusedoff))
455 #define cg_blksfree(cgp) \
456     ((u_int8_t *)((u_int8_t *)(cgp) + (cgp)->cg_freeoff))
457 #define cg_clustersfree(cgp) \
458     ((u_int8_t *)((u_int8_t *)(cgp) + (cgp)->cg_clusteroff))
459 #define cg_clustersum(cgp) \
460     ((int32_t *)((u_int8_t *)(cgp) + (cgp)->cg_clustersumoff))
461 
462 /*
463  * Turn filesystem block numbers into disk block addresses.
464  * This maps filesystem blocks to device size blocks.
465  */
466 #define fsbtodb(fs, b)	((b) << (fs)->fs_fsbtodb)
467 #define	dbtofsb(fs, b)	((b) >> (fs)->fs_fsbtodb)
468 
469 /*
470  * Cylinder group macros to locate things in cylinder groups.
471  * They calc filesystem addresses of cylinder group data structures.
472  */
473 #define	cgbase(fs, c)	((ufs2_daddr_t)((fs)->fs_fpg * (c)))
474 #define	cgdmin(fs, c)	(cgstart(fs, c) + (fs)->fs_dblkno)	/* 1st data */
475 #define	cgimin(fs, c)	(cgstart(fs, c) + (fs)->fs_iblkno)	/* inode blk */
476 #define	cgsblock(fs, c)	(cgstart(fs, c) + (fs)->fs_sblkno)	/* super blk */
477 #define	cgtod(fs, c)	(cgstart(fs, c) + (fs)->fs_cblkno)	/* cg block */
478 #define cgstart(fs, c)							\
479        ((fs)->fs_magic == FS_UFS2_MAGIC ? cgbase(fs, c) :		\
480        (cgbase(fs, c) + (fs)->fs_old_cgoffset * ((c) & ~((fs)->fs_old_cgmask))))
481 
482 /*
483  * Macros for handling inode numbers:
484  *     inode number to filesystem block offset.
485  *     inode number to cylinder group number.
486  *     inode number to filesystem block address.
487  */
488 #define	ino_to_cg(fs, x)	((x) / (fs)->fs_ipg)
489 #define	ino_to_fsba(fs, x)						\
490 	((ufs2_daddr_t)(cgimin(fs, ino_to_cg(fs, x)) +			\
491 	    (blkstofrags((fs), (((x) % (fs)->fs_ipg) / INOPB(fs))))))
492 #define	ino_to_fsbo(fs, x)	((x) % INOPB(fs))
493 
494 /*
495  * Give cylinder group number for a filesystem block.
496  * Give cylinder group block number for a filesystem block.
497  */
498 #define	dtog(fs, d)	((d) / (fs)->fs_fpg)
499 #define	dtogd(fs, d)	((d) % (fs)->fs_fpg)
500 
501 /*
502  * Extract the bits for a block from a map.
503  * Compute the cylinder and rotational position of a cyl block addr.
504  */
505 #define blkmap(fs, map, loc) \
506     (((map)[(loc) / NBBY] >> ((loc) % NBBY)) & (0xff >> (NBBY - (fs)->fs_frag)))
507 
508 /*
509  * The following macros optimize certain frequently calculated
510  * quantities by using shifts and masks in place of divisions
511  * modulos and multiplications.
512  */
513 #define blkoff(fs, loc)		/* calculates (loc % fs->fs_bsize) */ \
514 	((loc) & (fs)->fs_qbmask)
515 #define fragoff(fs, loc)	/* calculates (loc % fs->fs_fsize) */ \
516 	((loc) & (fs)->fs_qfmask)
517 #define lfragtosize(fs, frag)	/* calculates ((off_t)frag * fs->fs_fsize) */ \
518 	((off_t)(frag) << (fs)->fs_fshift)
519 #define lblktosize(fs, blk)	/* calculates ((off_t)blk * fs->fs_bsize) */ \
520 	((off_t)(blk) << (fs)->fs_bshift)
521 /* Use this only when `blk' is known to be small, e.g., < NDADDR. */
522 #define smalllblktosize(fs, blk)    /* calculates (blk * fs->fs_bsize) */ \
523 	((blk) << (fs)->fs_bshift)
524 #define lblkno(fs, loc)		/* calculates (loc / fs->fs_bsize) */ \
525 	((loc) >> (fs)->fs_bshift)
526 #define numfrags(fs, loc)	/* calculates (loc / fs->fs_fsize) */ \
527 	((loc) >> (fs)->fs_fshift)
528 #define blkroundup(fs, size)	/* calculates roundup(size, fs->fs_bsize) */ \
529 	(((size) + (fs)->fs_qbmask) & (fs)->fs_bmask)
530 #define fragroundup(fs, size)	/* calculates roundup(size, fs->fs_fsize) */ \
531 	(((size) + (fs)->fs_qfmask) & (fs)->fs_fmask)
532 #define fragstoblks(fs, frags)	/* calculates (frags / fs->fs_frag) */ \
533 	((frags) >> (fs)->fs_fragshift)
534 #define blkstofrags(fs, blks)	/* calculates (blks * fs->fs_frag) */ \
535 	((blks) << (fs)->fs_fragshift)
536 #define fragnum(fs, fsb)	/* calculates (fsb % fs->fs_frag) */ \
537 	((fsb) & ((fs)->fs_frag - 1))
538 #define blknum(fs, fsb)		/* calculates rounddown(fsb, fs->fs_frag) */ \
539 	((fsb) &~ ((fs)->fs_frag - 1))
540 
541 /*
542  * Determine the number of available frags given a
543  * percentage to hold in reserve.
544  */
545 #define freespace(fs, percentreserved) \
546 	(blkstofrags((fs), (fs)->fs_cstotal.cs_nbfree) + \
547 	(fs)->fs_cstotal.cs_nffree - \
548 	((off_t)((fs)->fs_dsize) * (percentreserved) / 100))
549 
550 /*
551  * Determining the size of a file block in the filesystem.
552  */
553 #define blksize(fs, ip, lbn) \
554 	(((lbn) >= NDADDR || (ip)->i_size >= smalllblktosize(fs, (lbn) + 1)) \
555 	    ? (fs)->fs_bsize \
556 	    : (fragroundup(fs, blkoff(fs, (ip)->i_size))))
557 #define sblksize(fs, size, lbn) \
558 	(((lbn) >= NDADDR || (size) >= ((lbn) + 1) << (fs)->fs_bshift) \
559 	  ? (fs)->fs_bsize \
560 	  : (fragroundup(fs, blkoff(fs, (size)))))
561 
562 
563 /*
564  * Number of inodes in a secondary storage block/fragment.
565  */
566 #define	INOPB(fs)	((fs)->fs_inopb)
567 #define	INOPF(fs)	((fs)->fs_inopb >> (fs)->fs_fragshift)
568 
569 /*
570  * Number of indirects in a filesystem block.
571  */
572 #define	NINDIR(fs)	((fs)->fs_nindir)
573 
574 extern int inside[], around[];
575 extern u_char *fragtbl[];
576 
577 #endif
578