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31 .\" @(#)disklabel.5.5 8.1 (Berkeley) 6/5/93
43 Each disk or disk pack on a system may contain a disk label
44 which provides detailed information
45 about the geometry of the disk and the partitions into which the disk
47 It should be initialized when the disk is formatted,
48 and may be changed later with the
51 This information is used by the system disk driver and by the bootstrap
52 program to determine how to program the drive
53 and where to find the file systems on the disk partitions.
54 Additional information is used by the file system in order
55 to use the disk most efficiently and to locate important file system information.
56 The description of each partition contains an identifier for the partition
57 type (standard file system, swap area, etc.).
58 The file system updates the in-core copy of the label if it contains
59 incomplete information about the file system.
61 The label is located in sector number
63 of the drive, usually sector 0 where it may be found
64 without any information about the disk geometry.
67 from the beginning of the sector, to allow room for the initial bootstrap.
68 The disk sector containing the label is normally made read-only
69 so that it is not accidentally overwritten by pack-to-pack copies
74 which is done as needed by the
78 A copy of the in-core label for a disk can be obtained with the
81 this works with a file descriptor for a block or character (``raw'') device
82 for any partition of the disk.
83 The in-core copy of the label is set by the
86 The offset of a partition cannot generally be changed while it is open,
87 nor can it be made smaller while it is open.
88 One exception is that any change is allowed if no label was found
89 on the disk, and the driver was able to construct only a skeletal label
90 without partition information.
94 operation sets the in-core label and then updates the on-disk label;
95 there must be an existing label on the disk for this operation to succeed.
96 Thus, the initial label for a disk or disk pack must be installed
97 by writing to the raw disk.
98 All of these operations are normally done using
101 The format of the disk label, as specified in
102 .In sys/disklabel.h ,
105 #ifndef _SYS_DISKLABEL_H_
106 #define _SYS_DISKLABEL_H_
109 #include <sys/types.h>
111 #include <sys/ioccom.h>
114 * Disk description table, see disktab(5)
116 #define _PATH_DISKTAB "/etc/disktab"
117 #define DISKTAB "/etc/disktab" /* deprecated */
120 * Each disk has a label which includes information about the hardware
121 * disk geometry, file system partitions, and drive specific information.
122 * The label is in block 0 or 1, possibly offset from the beginning
123 * to leave room for a bootstrap, etc.
126 /* XXX these should be defined per controller (or drive) elsewhere, not here! */
128 #define LABELSECTOR 1 /* sector containing label */
129 #define LABELOFFSET 0 /* offset of label in sector */
133 #define LABELSECTOR 0
134 #define LABELOFFSET 64
138 #define LABELSECTOR 0 /* sector containing label */
142 #define LABELOFFSET 64 /* offset of label in sector */
145 #define DISKMAGIC ((u_int32_t)0x82564557) /* The disk magic number */
146 #ifndef MAXPARTITIONS
147 #define MAXPARTITIONS 8
150 #define LABEL_PART 2 /* partition containing label */
151 #define RAW_PART 2 /* partition containing whole disk */
152 #define SWAP_PART 1 /* partition normally containing swap */
156 u_int32_t d_magic; /* the magic number */
157 u_int16_t d_type; /* drive type */
158 u_int16_t d_subtype; /* controller/d_type specific */
159 char d_typename[16]; /* type name, e.g. "eagle" */
160 char d_packname[16]; /* pack identifier */
163 u_int32_t d_secsize; /* # of bytes per sector */
164 u_int32_t d_nsectors; /* # of data sectors per track */
165 u_int32_t d_ntracks; /* # of tracks per cylinder */
166 u_int32_t d_ncylinders; /* # of data cylinders per unit */
167 u_int32_t d_secpercyl; /* # of data sectors per cylinder */
168 u_int32_t d_secperunit; /* # of data sectors per unit */
171 * Spares (bad sector replacements) below are not counted in
172 * d_nsectors or d_secpercyl. Spare sectors are assumed to
173 * be physical sectors which occupy space at the end of each
174 * track and/or cylinder.
176 u_int16_t d_sparespertrack; /* # of spare sectors per track */
177 u_int16_t d_sparespercyl; /* # of spare sectors per cylinder */
179 * Alternate cylinders include maintenance, replacement, configuration
180 * description areas, etc.
182 u_int32_t d_acylinders; /* # of alt. cylinders per unit */
184 /* hardware characteristics: */
186 * d_interleave, d_trackskew and d_cylskew describe perturbations
187 * in the media format used to compensate for a slow controller.
188 * Interleave is physical sector interleave, set up by the
189 * formatter or controller when formatting. When interleaving is
190 * in use, logically adjacent sectors are not physically
191 * contiguous, but instead are separated by some number of
192 * sectors. It is specified as the ratio of physical sectors
193 * traversed per logical sector. Thus an interleave of 1:1
194 * implies contiguous layout, while 2:1 implies that logical
195 * sector 0 is separated by one sector from logical sector 1.
196 * d_trackskew is the offset of sector 0 on track N relative to
197 * sector 0 on track N-1 on the same cylinder. Finally, d_cylskew
198 * is the offset of sector 0 on cylinder N relative to sector 0
201 u_int16_t d_rpm; /* rotational speed */
202 u_int16_t d_interleave; /* hardware sector interleave */
203 u_int16_t d_trackskew; /* sector 0 skew, per track */
204 u_int16_t d_cylskew; /* sector 0 skew, per cylinder */
205 u_int32_t d_headswitch; /* head switch time, usec */
206 u_int32_t d_trkseek; /* track-to-track seek, usec */
207 u_int32_t d_flags; /* generic flags */
209 u_int32_t d_drivedata[NDDATA]; /* drive-type specific information */
211 u_int32_t d_spare[NSPARE]; /* reserved for future use */
212 u_int32_t d_magic2; /* the magic number (again) */
213 u_int16_t d_checksum; /* xor of data incl. partitions */
215 /* file system and partition information: */
216 u_int16_t d_npartitions; /* number of partitions in following */
217 u_int32_t d_bbsize; /* size of boot area at sn0, bytes */
218 u_int32_t d_sbsize; /* max size of fs superblock, bytes */
219 struct partition { /* the partition table */
220 u_int32_t p_size; /* number of sectors in partition */
221 u_int32_t p_offset; /* starting sector */
222 u_int32_t p_fsize; /* file system basic fragment size */
223 u_int8_t p_fstype; /* file system type, see below */
224 u_int8_t p_frag; /* file system fragments per block */
226 u_int16_t cpg; /* UFS: FS cylinders per group */
227 u_int16_t sgs; /* LFS: FS segment shift */
229 #define p_cpg __partition_u1.cpg
230 #define p_sgs __partition_u1.sgs
231 } d_partitions[MAXPARTITIONS]; /* actually may be more */
235 * offsets for asm boot files.
243 .set d_end_,276 /* size of disk label */
247 #define DTYPE_SMD 1 /* SMD, XSMD; VAX hp/up */
248 #define DTYPE_MSCP 2 /* MSCP */
249 #define DTYPE_DEC 3 /* other DEC (rk, rl) */
250 #define DTYPE_SCSI 4 /* SCSI */
251 #define DTYPE_ESDI 5 /* ESDI interface */
252 #define DTYPE_ST506 6 /* ST506 etc. */
253 #define DTYPE_HPIB 7 /* CS/80 on HP-IB */
254 #define DTYPE_HPFL 8 /* HP Fiber-link */
255 #define DTYPE_FLOPPY 10 /* floppy */
256 #define DTYPE_CCD 11 /* concatenated disk */
257 #define DTYPE_VINUM 12 /* vinum volume */
258 #define DTYPE_DOC2K 13 /* Msys DiskOnChip */
260 #if defined(PC98) && !defined(PC98_ATCOMPAT)
261 #define DSTYPE_SEC256 0x80 /* physical sector size=256 */
265 static char *dktypenames[] = {
282 #define DKMAXTYPES (sizeof(dktypenames) / sizeof(dktypenames[0]) - 1)
286 * File system type and version.
287 * Used to interpret other file system-specific
288 * per-partition information.
290 #define FS_UNUSED 0 /* unused */
291 #define FS_SWAP 1 /* swap */
292 #define FS_V6 2 /* Sixth Edition */
293 #define FS_V7 3 /* Seventh Edition */
294 #define FS_SYSV 4 /* System V */
295 #define FS_V71K 5 /* V7 with 1K blocks (4.1, 2.9) */
296 #define FS_V8 6 /* Eighth Edition, 4K blocks */
297 #define FS_BSDFFS 7 /* 4.2BSD fast file system */
298 #define FS_MSDOS 8 /* MSDOS file system */
299 #define FS_BSDLFS 9 /* 4.4BSD log-structured file system */
300 #define FS_OTHER 10 /* in use, but unknown/unsupported */
301 #define FS_HPFS 11 /* OS/2 high-performance file system */
302 #define FS_ISO9660 12 /* ISO 9660, normally CD-ROM */
303 #define FS_BOOT 13 /* partition contains bootstrap */
304 #define FS_VINUM 14 /* Vinum drive */
307 static char *fstypenames[] = {
325 #define FSMAXTYPES (sizeof(fstypenames) / sizeof(fstypenames[0]) - 1)
329 * flags shared by various drives:
331 #define D_REMOVABLE 0x01 /* removable media */
332 #define D_ECC 0x02 /* supports ECC */
333 #define D_BADSECT 0x04 /* supports bad sector forw. */
334 #define D_RAMDISK 0x08 /* disk emulator */
335 #define D_CHAIN 0x10 /* can do back-back transfers */
338 * Drive data for SMD.
340 #define d_smdflags d_drivedata[0]
341 #define D_SSE 0x1 /* supports skip sectoring */
342 #define d_mindist d_drivedata[1]
343 #define d_maxdist d_drivedata[2]
344 #define d_sdist d_drivedata[3]
347 * Drive data for ST506.
349 #define d_precompcyl d_drivedata[0]
350 #define d_gap3 d_drivedata[1] /* used only when formatting */
353 * Drive data for SCSI.
355 #define d_blind d_drivedata[0]
359 * Structure used to perform a format or other raw operation, returning
360 * data and/or register values. Register identification and format
361 * are device- and driver-dependent.
365 int df_count; /* value-result */
367 int df_reg[8]; /* result */
371 * Structure used internally to retrieve information about a partition
375 struct disklabel *disklab;
376 struct partition *part;
379 /* DOS partition table -- located in boot block */
381 #if defined(PC98) && !defined(PC98_ATCOMPAT)
382 #define DOSBBSECTOR 0 /* DOS boot block relative sector number */
383 #define DOSLABELSECTOR 1 /* 0: 256b/s, 1: 512b/s */
386 #define DOSPTYP_386BSD 0x94 /* 386BSD partition type */
387 #define MBR_PTYPE_FreeBSD 0x94 /* FreeBSD partition type */
389 struct dos_partition {
390 unsigned char dp_mid;
391 #define DOSMID_386BSD (0x14|0x80) /* 386bsd|bootable */
392 unsigned char dp_sid;
393 #define DOSSID_386BSD (0x44|0x80) /* 386bsd|active */
394 unsigned char dp_dum1;
395 unsigned char dp_dum2;
396 unsigned char dp_ipl_sct;
397 unsigned char dp_ipl_head;
398 unsigned short dp_ipl_cyl;
399 unsigned char dp_ssect; /* starting sector */
400 unsigned char dp_shd; /* starting head */
401 unsigned short dp_scyl; /* starting cylinder */
402 unsigned char dp_esect; /* end sector */
403 unsigned char dp_ehd; /* end head */
404 unsigned short dp_ecyl; /* end cylinder */
405 unsigned char dp_name[16];
409 #define DOSBBSECTOR 0 /* DOS boot block relative sector number */
410 #define DOSPARTOFF 446
412 #define DOSPTYP_386BSD 0xa5 /* 386BSD partition type */
414 struct dos_partition {
415 unsigned char dp_flag; /* bootstrap flags */
416 unsigned char dp_shd; /* starting head */
417 unsigned char dp_ssect; /* starting sector */
418 unsigned char dp_scyl; /* starting cylinder */
419 unsigned char dp_typ; /* partition type */
420 unsigned char dp_ehd; /* end head */
421 unsigned char dp_esect; /* end sector */
422 unsigned char dp_ecyl; /* end cylinder */
423 u_int32_t dp_start; /* absolute starting sector number */
424 u_int32_t dp_size; /* partition size in sectors */
428 #define DPSECT(s) ((s) & 0x3f) /* isolate relevant bits of sector */
429 #define DPCYL(c, s) ((c) + (((s) & 0xc0)<<2)) /* and those that are cylinder */
432 * Disk-specific ioctls.
434 /* get and set disklabel; DIOCGPART used internally */
435 #define DIOCGDINFO _IOR('d', 101, struct disklabel)/* get */
436 #define DIOCSDINFO _IOW('d', 102, struct disklabel)/* set */
437 #define DIOCWDINFO _IOW('d', 103, struct disklabel)/* set, update disk */
438 #define DIOCGPART _IOW('d', 104, struct partinfo) /* get partition */
440 #define DIOCWLABEL _IOW('d', 109, int) /* write en/disable label */
445 * XXX encoding of disk minor numbers, should be elsewhere.
447 * See <sys/reboot.h> for a possibly better encoding.
449 * "cpio -H newc" can be used to back up device files with large minor
450 * numbers (but not ones >= 2^31). Old cpio formats and all tar formats
451 * don't have enough bits, and cpio and tar don't notice the lossage.
452 * There are also some sign extension bugs.
457 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
458 _________________________________________________________________
459 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
460 -----------------------------------------------------------------
461 | TYPE |UNIT_2 | SLICE | MAJOR? | UNIT |PART |
462 -----------------------------------------------------------------
464 #define dkmakeminor(unit, slice, part) \e
465 (((slice) << 16) | (((unit) & 0x1e0) << 16) | \e
466 (((unit) & 0x1f) << 3) | (part))
467 static __inline dev_t
468 dkmodpart(dev_t dev, int part)
470 return (makedev(major(dev), (minor(dev) & ~7) | part));
473 static __inline dev_t
474 dkmodslice(dev_t dev, int slice)
476 return (makedev(major(dev), (minor(dev) & ~0x1f0000) | (slice << 16)));
479 #define dkpart(dev) (minor(dev) & 7)
480 #define dkslice(dev) ((minor(dev) >> 16) & 0x1f)
481 #define dktype(dev) ((minor(dev) >> 25) & 0x7f)
483 static __inline u_int
486 return (((minor(dev) >> 16) & 0x1e0) | ((minor(dev) >> 3) & 0x1f));
490 struct buf_queue_head;
492 int bounds_check_with_label(struct buf *bp, struct disklabel *lp,
494 void diskerr(struct buf *bp, char *what, int pri, int blkdone,
495 struct disklabel *lp);
496 void disksort(struct buf *ap, struct buf *bp);
497 u_int dkcksum struct disklabel *lp);
498 char *readdisklabel(dev_t dev, struct disklabel *lp);
499 void bufqdisksort(struct buf_queue_head *ap, struct buf *bp);
500 int setdisklabel(struct disklabel *olp, struct disklabel *nlp,
502 int writedisklabel(dev_t dev, struct disklabel *lp);
504 void alpha_fix_srm_checksum(struct buf *bp);
513 struct disklabel *getdiskbyname(const char *);
517 #endif /* !_SYS_DISKLABEL_H_ */