xref: /freebsd/sys/ufs/ffs/fs.h (revision afe61c15161c324a7af299a9b8457aba5afc92db)
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	8.7 (Berkeley) 4/19/94
34  */
35 
36 /*
37  * Each disk drive contains some number of file systems.
38  * A file system consists of a number of cylinder groups.
39  * Each cylinder group has inodes and data.
40  *
41  * A file system is described by its super-block, which in turn
42  * describes the cylinder groups.  The super-block is critical
43  * data and is replicated in each cylinder group to protect against
44  * catastrophic loss.  This is done at `newfs' time and the critical
45  * super-block data does not change, so the copies need not be
46  * referenced further unless disaster strikes.
47  *
48  * For file system fs, the offsets of the various blocks of interest
49  * are given in the super block as:
50  *	[fs->fs_sblkno]		Super-block
51  *	[fs->fs_cblkno]		Cylinder group block
52  *	[fs->fs_iblkno]		Inode blocks
53  *	[fs->fs_dblkno]		Data blocks
54  * The beginning of cylinder group cg in fs, is given by
55  * the ``cgbase(fs, cg)'' macro.
56  *
57  * The first boot and super blocks are given in absolute disk addresses.
58  * The byte-offset forms are preferred, as they don't imply a sector size.
59  */
60 #define BBSIZE		8192
61 #define SBSIZE		8192
62 #define	BBOFF		((off_t)(0))
63 #define	SBOFF		((off_t)(BBOFF + BBSIZE))
64 #define	BBLOCK		((daddr_t)(0))
65 #define	SBLOCK		((daddr_t)(BBLOCK + BBSIZE / DEV_BSIZE))
66 
67 /*
68  * Addresses stored in inodes are capable of addressing fragments
69  * of `blocks'. File system blocks of at most size MAXBSIZE can
70  * be optionally broken into 2, 4, or 8 pieces, each of which is
71  * addressible; these pieces may be DEV_BSIZE, or some multiple of
72  * a DEV_BSIZE unit.
73  *
74  * Large files consist of exclusively large data blocks.  To avoid
75  * undue wasted disk space, the last data block of a small file may be
76  * allocated as only as many fragments of a large block as are
77  * necessary.  The file system format retains only a single pointer
78  * to such a fragment, which is a piece of a single large block that
79  * has been divided.  The size of such a fragment is determinable from
80  * information in the inode, using the ``blksize(fs, ip, lbn)'' macro.
81  *
82  * The file system records space availability at the fragment level;
83  * to determine block availability, aligned fragments are examined.
84  */
85 
86 /*
87  * MINBSIZE is the smallest allowable block size.
88  * In order to insure that it is possible to create files of size
89  * 2^32 with only two levels of indirection, MINBSIZE is set to 4096.
90  * MINBSIZE must be big enough to hold a cylinder group block,
91  * thus changes to (struct cg) must keep its size within MINBSIZE.
92  * Note that super blocks are always of size SBSIZE,
93  * and that both SBSIZE and MAXBSIZE must be >= MINBSIZE.
94  */
95 #define MINBSIZE	4096
96 
97 /*
98  * The path name on which the file system is mounted is maintained
99  * in fs_fsmnt. MAXMNTLEN defines the amount of space allocated in
100  * the super block for this name.
101  * The limit on the amount of summary information per file system
102  * is defined by MAXCSBUFS. It is currently parameterized for a
103  * maximum of two million cylinders.
104  */
105 #define MAXMNTLEN 512
106 #define MAXCSBUFS 32
107 
108 /*
109  * A summary of contiguous blocks of various sizes is maintained
110  * in each cylinder group. Normally this is set by the initial
111  * value of fs_maxcontig. To conserve space, a maximum summary size
112  * is set by FS_MAXCONTIG.
113  */
114 #define FS_MAXCONTIG	16
115 
116 /*
117  * MINFREE gives the minimum acceptable percentage of file system
118  * blocks which may be free. If the freelist drops below this level
119  * only the superuser may continue to allocate blocks. This may
120  * be set to 0 if no reserve of free blocks is deemed necessary,
121  * however throughput drops by fifty percent if the file system
122  * is run at between 95% and 100% full; thus the minimum default
123  * value of fs_minfree is 5%. However, to get good clustering
124  * performance, 10% is a better choice. hence we use 10% as our
125  * default value. With 10% free space, fragmentation is not a
126  * problem, so we choose to optimize for time.
127  */
128 #define MINFREE		5
129 #define DEFAULTOPT	FS_OPTTIME
130 
131 /*
132  * Per cylinder group information; summarized in blocks allocated
133  * from first cylinder group data blocks.  These blocks have to be
134  * read in from fs_csaddr (size fs_cssize) in addition to the
135  * super block.
136  *
137  * N.B. sizeof(struct csum) must be a power of two in order for
138  * the ``fs_cs'' macro to work (see below).
139  */
140 struct csum {
141 	long	cs_ndir;	/* number of directories */
142 	long	cs_nbfree;	/* number of free blocks */
143 	long	cs_nifree;	/* number of free inodes */
144 	long	cs_nffree;	/* number of free frags */
145 };
146 
147 /*
148  * Super block for a file system.
149  */
150 struct fs {
151 	struct	fs *fs_link;		/* linked list of file systems */
152 	struct	fs *fs_rlink;		/*     used for incore super blocks */
153 	daddr_t	fs_sblkno;		/* addr of super-block in filesys */
154 	daddr_t	fs_cblkno;		/* offset of cyl-block in filesys */
155 	daddr_t	fs_iblkno;		/* offset of inode-blocks in filesys */
156 	daddr_t	fs_dblkno;		/* offset of first data after cg */
157 	long	fs_cgoffset;		/* cylinder group offset in cylinder */
158 	long	fs_cgmask;		/* used to calc mod fs_ntrak */
159 	time_t 	fs_time;    		/* last time written */
160 	long	fs_size;		/* number of blocks in fs */
161 	long	fs_dsize;		/* number of data blocks in fs */
162 	long	fs_ncg;			/* number of cylinder groups */
163 	long	fs_bsize;		/* size of basic blocks in fs */
164 	long	fs_fsize;		/* size of frag blocks in fs */
165 	long	fs_frag;		/* number of frags in a block in fs */
166 /* these are configuration parameters */
167 	long	fs_minfree;		/* minimum percentage of free blocks */
168 	long	fs_rotdelay;		/* num of ms for optimal next block */
169 	long	fs_rps;			/* disk revolutions per second */
170 /* these fields can be computed from the others */
171 	long	fs_bmask;		/* ``blkoff'' calc of blk offsets */
172 	long	fs_fmask;		/* ``fragoff'' calc of frag offsets */
173 	long	fs_bshift;		/* ``lblkno'' calc of logical blkno */
174 	long	fs_fshift;		/* ``numfrags'' calc number of frags */
175 /* these are configuration parameters */
176 	long	fs_maxcontig;		/* max number of contiguous blks */
177 	long	fs_maxbpg;		/* max number of blks per cyl group */
178 /* these fields can be computed from the others */
179 	long	fs_fragshift;		/* block to frag shift */
180 	long	fs_fsbtodb;		/* fsbtodb and dbtofsb shift constant */
181 	long	fs_sbsize;		/* actual size of super block */
182 	long	fs_csmask;		/* csum block offset */
183 	long	fs_csshift;		/* csum block number */
184 	long	fs_nindir;		/* value of NINDIR */
185 	long	fs_inopb;		/* value of INOPB */
186 	long	fs_nspf;		/* value of NSPF */
187 /* yet another configuration parameter */
188 	long	fs_optim;		/* optimization preference, see below */
189 /* these fields are derived from the hardware */
190 	long	fs_npsect;		/* # sectors/track including spares */
191 	long	fs_interleave;		/* hardware sector interleave */
192 	long	fs_trackskew;		/* sector 0 skew, per track */
193 	long	fs_headswitch;		/* head switch time, usec */
194 	long	fs_trkseek;		/* track-to-track seek, usec */
195 /* sizes determined by number of cylinder groups and their sizes */
196 	daddr_t fs_csaddr;		/* blk addr of cyl grp summary area */
197 	long	fs_cssize;		/* size of cyl grp summary area */
198 	long	fs_cgsize;		/* cylinder group size */
199 /* these fields are derived from the hardware */
200 	long	fs_ntrak;		/* tracks per cylinder */
201 	long	fs_nsect;		/* sectors per track */
202 	long  	fs_spc;   		/* sectors per cylinder */
203 /* this comes from the disk driver partitioning */
204 	long	fs_ncyl;   		/* cylinders in file system */
205 /* these fields can be computed from the others */
206 	long	fs_cpg;			/* cylinders per group */
207 	long	fs_ipg;			/* inodes per group */
208 	long	fs_fpg;			/* blocks per group * fs_frag */
209 /* this data must be re-computed after crashes */
210 	struct	csum fs_cstotal;	/* cylinder summary information */
211 /* these fields are cleared at mount time */
212 	char   	fs_fmod;    		/* super block modified flag */
213 	char   	fs_clean;    		/* file system is clean flag */
214 	char   	fs_ronly;   		/* mounted read-only flag */
215 	char   	fs_flags;   		/* currently unused flag */
216 	char	fs_fsmnt[MAXMNTLEN];	/* name mounted on */
217 /* these fields retain the current block allocation info */
218 	long	fs_cgrotor;		/* last cg searched */
219 	struct	csum *fs_csp[MAXCSBUFS];/* list of fs_cs info buffers */
220 	long	fs_cpc;			/* cyl per cycle in postbl */
221 	short	fs_opostbl[16][8];	/* old rotation block list head */
222 	long	fs_sparecon[50];	/* reserved for future constants */
223 	long	fs_contigsumsize;	/* size of cluster summary array */
224 	long	fs_maxsymlinklen;	/* max length of an internal symlink */
225 	long	fs_inodefmt;		/* format of on-disk inodes */
226 	u_quad_t fs_maxfilesize;	/* maximum representable file size */
227 	quad_t	fs_qbmask;		/* ~fs_bmask - for use with quad size */
228 	quad_t	fs_qfmask;		/* ~fs_fmask - for use with quad size */
229 	long	fs_state;		/* validate fs_clean field */
230 	long	fs_postblformat;	/* format of positional layout tables */
231 	long	fs_nrpos;		/* number of rotational positions */
232 	long	fs_postbloff;		/* (short) rotation block list head */
233 	long	fs_rotbloff;		/* (u_char) blocks for each rotation */
234 	long	fs_magic;		/* magic number */
235 	u_char	fs_space[1];		/* list of blocks for each rotation */
236 /* actually longer */
237 };
238 /*
239  * Filesystem idetification
240  */
241 #define	FS_MAGIC	0x011954	/* the fast filesystem magic number */
242 #define	FS_OKAY		0x7c269d38	/* superblock checksum */
243 #define FS_42INODEFMT	-1		/* 4.2BSD inode format */
244 #define FS_44INODEFMT	2		/* 4.4BSD inode format */
245 /*
246  * Preference for optimization.
247  */
248 #define FS_OPTTIME	0	/* minimize allocation time */
249 #define FS_OPTSPACE	1	/* minimize disk fragmentation */
250 
251 /*
252  * Rotational layout table format types
253  */
254 #define FS_42POSTBLFMT		-1	/* 4.2BSD rotational table format */
255 #define FS_DYNAMICPOSTBLFMT	1	/* dynamic rotational table format */
256 /*
257  * Macros for access to superblock array structures
258  */
259 #define fs_postbl(fs, cylno) \
260     (((fs)->fs_postblformat == FS_42POSTBLFMT) \
261     ? ((fs)->fs_opostbl[cylno]) \
262     : ((short *)((char *)(fs) + (fs)->fs_postbloff) + (cylno) * (fs)->fs_nrpos))
263 #define fs_rotbl(fs) \
264     (((fs)->fs_postblformat == FS_42POSTBLFMT) \
265     ? ((fs)->fs_space) \
266     : ((u_char *)((char *)(fs) + (fs)->fs_rotbloff)))
267 
268 /*
269  * The size of a cylinder group is calculated by CGSIZE. The maximum size
270  * is limited by the fact that cylinder groups are at most one block.
271  * Its size is derived from the size of the maps maintained in the
272  * cylinder group and the (struct cg) size.
273  */
274 #define CGSIZE(fs) \
275     /* base cg */	(sizeof(struct cg) + sizeof(long) + \
276     /* blktot size */	(fs)->fs_cpg * sizeof(long) + \
277     /* blks size */	(fs)->fs_cpg * (fs)->fs_nrpos * sizeof(short) + \
278     /* inode map */	howmany((fs)->fs_ipg, NBBY) + \
279     /* block map */	howmany((fs)->fs_cpg * (fs)->fs_spc / NSPF(fs), NBBY) +\
280     /* if present */	((fs)->fs_contigsumsize <= 0 ? 0 : \
281     /* cluster sum */	(fs)->fs_contigsumsize * sizeof(long) + \
282     /* cluster map */	howmany((fs)->fs_cpg * (fs)->fs_spc / NSPB(fs), NBBY)))
283 
284 /*
285  * Convert cylinder group to base address of its global summary info.
286  *
287  * N.B. This macro assumes that sizeof(struct csum) is a power of two.
288  */
289 #define fs_cs(fs, indx) \
290 	fs_csp[(indx) >> (fs)->fs_csshift][(indx) & ~(fs)->fs_csmask]
291 
292 /*
293  * Cylinder group block for a file system.
294  */
295 #define	CG_MAGIC	0x090255
296 struct	cg {
297 	struct	cg *cg_link;		/* linked list of cyl groups */
298 	long	cg_magic;		/* magic number */
299 	time_t	cg_time;		/* time last written */
300 	long	cg_cgx;			/* we are the cgx'th cylinder group */
301 	short	cg_ncyl;		/* number of cyl's this cg */
302 	short	cg_niblk;		/* number of inode blocks this cg */
303 	long	cg_ndblk;		/* number of data blocks this cg */
304 	struct	csum cg_cs;		/* cylinder summary information */
305 	long	cg_rotor;		/* position of last used block */
306 	long	cg_frotor;		/* position of last used frag */
307 	long	cg_irotor;		/* position of last used inode */
308 	long	cg_frsum[MAXFRAG];	/* counts of available frags */
309 	long	cg_btotoff;		/* (long) block totals per cylinder */
310 	long	cg_boff;		/* (short) free block positions */
311 	long	cg_iusedoff;		/* (char) used inode map */
312 	long	cg_freeoff;		/* (u_char) free block map */
313 	long	cg_nextfreeoff;		/* (u_char) next available space */
314 	long	cg_clustersumoff;	/* (long) counts of avail clusters */
315 	long	cg_clusteroff;		/* (char) free cluster map */
316 	long	cg_nclusterblks;	/* number of clusters this cg */
317 	long	cg_sparecon[13];	/* reserved for future use */
318 	u_char	cg_space[1];		/* space for cylinder group maps */
319 /* actually longer */
320 };
321 /*
322  * Macros for access to cylinder group array structures
323  */
324 #define cg_blktot(cgp) \
325     (((cgp)->cg_magic != CG_MAGIC) \
326     ? (((struct ocg *)(cgp))->cg_btot) \
327     : ((long *)((char *)(cgp) + (cgp)->cg_btotoff)))
328 #define cg_blks(fs, cgp, cylno) \
329     (((cgp)->cg_magic != CG_MAGIC) \
330     ? (((struct ocg *)(cgp))->cg_b[cylno]) \
331     : ((short *)((char *)(cgp) + (cgp)->cg_boff) + (cylno) * (fs)->fs_nrpos))
332 #define cg_inosused(cgp) \
333     (((cgp)->cg_magic != CG_MAGIC) \
334     ? (((struct ocg *)(cgp))->cg_iused) \
335     : ((char *)((char *)(cgp) + (cgp)->cg_iusedoff)))
336 #define cg_blksfree(cgp) \
337     (((cgp)->cg_magic != CG_MAGIC) \
338     ? (((struct ocg *)(cgp))->cg_free) \
339     : ((u_char *)((char *)(cgp) + (cgp)->cg_freeoff)))
340 #define cg_chkmagic(cgp) \
341     ((cgp)->cg_magic == CG_MAGIC || ((struct ocg *)(cgp))->cg_magic == CG_MAGIC)
342 #define cg_clustersfree(cgp) \
343     ((u_char *)((char *)(cgp) + (cgp)->cg_clusteroff))
344 #define cg_clustersum(cgp) \
345     ((long *)((char *)(cgp) + (cgp)->cg_clustersumoff))
346 
347 /*
348  * The following structure is defined
349  * for compatibility with old file systems.
350  */
351 struct	ocg {
352 	struct	ocg *cg_link;		/* linked list of cyl groups */
353 	struct	ocg *cg_rlink;		/*     used for incore cyl groups */
354 	time_t	cg_time;		/* time last written */
355 	long	cg_cgx;			/* we are the cgx'th cylinder group */
356 	short	cg_ncyl;		/* number of cyl's this cg */
357 	short	cg_niblk;		/* number of inode blocks this cg */
358 	long	cg_ndblk;		/* number of data blocks this cg */
359 	struct	csum cg_cs;		/* cylinder summary information */
360 	long	cg_rotor;		/* position of last used block */
361 	long	cg_frotor;		/* position of last used frag */
362 	long	cg_irotor;		/* position of last used inode */
363 	long	cg_frsum[8];		/* counts of available frags */
364 	long	cg_btot[32];		/* block totals per cylinder */
365 	short	cg_b[32][8];		/* positions of free blocks */
366 	char	cg_iused[256];		/* used inode map */
367 	long	cg_magic;		/* magic number */
368 	u_char	cg_free[1];		/* free block map */
369 /* actually longer */
370 };
371 
372 /*
373  * Turn file system block numbers into disk block addresses.
374  * This maps file system blocks to device size blocks.
375  */
376 #define fsbtodb(fs, b)	((b) << (fs)->fs_fsbtodb)
377 #define	dbtofsb(fs, b)	((b) >> (fs)->fs_fsbtodb)
378 
379 /*
380  * Cylinder group macros to locate things in cylinder groups.
381  * They calc file system addresses of cylinder group data structures.
382  */
383 #define	cgbase(fs, c)	((daddr_t)((fs)->fs_fpg * (c)))
384 #define	cgdmin(fs, c)	(cgstart(fs, c) + (fs)->fs_dblkno)	/* 1st data */
385 #define	cgimin(fs, c)	(cgstart(fs, c) + (fs)->fs_iblkno)	/* inode blk */
386 #define	cgsblock(fs, c)	(cgstart(fs, c) + (fs)->fs_sblkno)	/* super blk */
387 #define	cgtod(fs, c)	(cgstart(fs, c) + (fs)->fs_cblkno)	/* cg block */
388 #define cgstart(fs, c)							\
389 	(cgbase(fs, c) + (fs)->fs_cgoffset * ((c) & ~((fs)->fs_cgmask)))
390 
391 /*
392  * Macros for handling inode numbers:
393  *     inode number to file system block offset.
394  *     inode number to cylinder group number.
395  *     inode number to file system block address.
396  */
397 #define	ino_to_cg(fs, x)	((x) / (fs)->fs_ipg)
398 #define	ino_to_fsba(fs, x)						\
399 	((daddr_t)(cgimin(fs, ino_to_cg(fs, x)) +			\
400 	    (blkstofrags((fs), (((x) % (fs)->fs_ipg) / INOPB(fs))))))
401 #define	ino_to_fsbo(fs, x)	((x) % INOPB(fs))
402 
403 /*
404  * Give cylinder group number for a file system block.
405  * Give cylinder group block number for a file system block.
406  */
407 #define	dtog(fs, d)	((d) / (fs)->fs_fpg)
408 #define	dtogd(fs, d)	((d) % (fs)->fs_fpg)
409 
410 /*
411  * Extract the bits for a block from a map.
412  * Compute the cylinder and rotational position of a cyl block addr.
413  */
414 #define blkmap(fs, map, loc) \
415     (((map)[(loc) / NBBY] >> ((loc) % NBBY)) & (0xff >> (NBBY - (fs)->fs_frag)))
416 #define cbtocylno(fs, bno) \
417     ((bno) * NSPF(fs) / (fs)->fs_spc)
418 #define cbtorpos(fs, bno) \
419     (((bno) * NSPF(fs) % (fs)->fs_spc / (fs)->fs_nsect * (fs)->fs_trackskew + \
420      (bno) * NSPF(fs) % (fs)->fs_spc % (fs)->fs_nsect * (fs)->fs_interleave) % \
421      (fs)->fs_nsect * (fs)->fs_nrpos / (fs)->fs_npsect)
422 
423 /*
424  * The following macros optimize certain frequently calculated
425  * quantities by using shifts and masks in place of divisions
426  * modulos and multiplications.
427  */
428 #define blkoff(fs, loc)		/* calculates (loc % fs->fs_bsize) */ \
429 	((loc) & (fs)->fs_qbmask)
430 #define fragoff(fs, loc)	/* calculates (loc % fs->fs_fsize) */ \
431 	((loc) & (fs)->fs_qfmask)
432 #define lblktosize(fs, blk)	/* calculates (blk * fs->fs_bsize) */ \
433 	((blk) << (fs)->fs_bshift)
434 #define lblkno(fs, loc)		/* calculates (loc / fs->fs_bsize) */ \
435 	((loc) >> (fs)->fs_bshift)
436 #define numfrags(fs, loc)	/* calculates (loc / fs->fs_fsize) */ \
437 	((loc) >> (fs)->fs_fshift)
438 #define blkroundup(fs, size)	/* calculates roundup(size, fs->fs_bsize) */ \
439 	(((size) + (fs)->fs_qbmask) & (fs)->fs_bmask)
440 #define fragroundup(fs, size)	/* calculates roundup(size, fs->fs_fsize) */ \
441 	(((size) + (fs)->fs_qfmask) & (fs)->fs_fmask)
442 #define fragstoblks(fs, frags)	/* calculates (frags / fs->fs_frag) */ \
443 	((frags) >> (fs)->fs_fragshift)
444 #define blkstofrags(fs, blks)	/* calculates (blks * fs->fs_frag) */ \
445 	((blks) << (fs)->fs_fragshift)
446 #define fragnum(fs, fsb)	/* calculates (fsb % fs->fs_frag) */ \
447 	((fsb) & ((fs)->fs_frag - 1))
448 #define blknum(fs, fsb)		/* calculates rounddown(fsb, fs->fs_frag) */ \
449 	((fsb) &~ ((fs)->fs_frag - 1))
450 
451 /*
452  * Determine the number of available frags given a
453  * percentage to hold in reserve
454  */
455 #define freespace(fs, percentreserved) \
456 	(blkstofrags((fs), (fs)->fs_cstotal.cs_nbfree) + \
457 	(fs)->fs_cstotal.cs_nffree - ((fs)->fs_dsize * (percentreserved) / 100))
458 
459 /*
460  * Determining the size of a file block in the file system.
461  */
462 #define blksize(fs, ip, lbn) \
463 	(((lbn) >= NDADDR || (ip)->i_size >= ((lbn) + 1) << (fs)->fs_bshift) \
464 	    ? (fs)->fs_bsize \
465 	    : (fragroundup(fs, blkoff(fs, (ip)->i_size))))
466 #define dblksize(fs, dip, lbn) \
467 	(((lbn) >= NDADDR || (dip)->di_size >= ((lbn) + 1) << (fs)->fs_bshift) \
468 	    ? (fs)->fs_bsize \
469 	    : (fragroundup(fs, blkoff(fs, (dip)->di_size))))
470 
471 /*
472  * Number of disk sectors per block; assumes DEV_BSIZE byte sector size.
473  */
474 #define	NSPB(fs)	((fs)->fs_nspf << (fs)->fs_fragshift)
475 #define	NSPF(fs)	((fs)->fs_nspf)
476 
477 /*
478  * INOPB is the number of inodes in a secondary storage block.
479  */
480 #define	INOPB(fs)	((fs)->fs_inopb)
481 #define	INOPF(fs)	((fs)->fs_inopb >> (fs)->fs_fragshift)
482 
483 /*
484  * NINDIR is the number of indirects in a file system block.
485  */
486 #define	NINDIR(fs)	((fs)->fs_nindir)
487 
488 extern int inside[], around[];
489 extern u_char *fragtbl[];
490