freebsd-src/sys/kern/subr_disklabel.c
Poul-Henning Kamp 1be9232f73 This basically allows you to stick a disklabel on any partition.
For it to be useful, you must stick your disklabel on the partition which
starts where the MBR says FreeBSD lives.  If you don't do that, you might
get a bad day.

Oh, that probably also means that putting swap there is a bad idea...
1994-10-17 02:31:33 +00:00

472 lines
14 KiB
C

/*
* Copyright (c) 1982, 1986, 1988, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)ufs_disksubr.c 8.5 (Berkeley) 1/21/94
* $Id: ufs_disksubr.c,v 1.4 1994/10/08 06:57:23 phk Exp $
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/buf.h>
#include <sys/disklabel.h>
#include <sys/syslog.h>
#include <sys/dkbad.h>
int dkcksum __P((struct disklabel *));
/*
* Seek sort for disks. We depend on the driver which calls us using b_resid
* as the current cylinder number.
*
* The argument ap structure holds a b_actf activity chain pointer on which we
* keep two queues, sorted in ascending cylinder order. The first queue holds
* those requests which are positioned after the current cylinder (in the first
* request); the second holds requests which came in after their cylinder number
* was passed. Thus we implement a one way scan, retracting after reaching the
* end of the drive to the first request on the second queue, at which time it
* becomes the first queue.
*
* A one-way scan is natural because of the way UNIX read-ahead blocks are
* allocated.
*/
/*
* For portability with historic industry practice, the
* cylinder number has to be maintained in the `b_resid'
* field.
*/
#define b_cylinder b_resid
void
disksort(ap, bp)
register struct buf *ap, *bp;
{
register struct buf *bq;
/* If the queue is empty, then it's easy. */
if (ap->b_actf == NULL) {
bp->b_actf = NULL;
ap->b_actf = bp;
return;
}
/*
* If we lie after the first (currently active) request, then we
* must locate the second request list and add ourselves to it.
*/
bq = ap->b_actf;
if (bp->b_cylinder < bq->b_cylinder) {
while (bq->b_actf) {
/*
* Check for an ``inversion'' in the normally ascending
* cylinder numbers, indicating the start of the second
* request list.
*/
if (bq->b_actf->b_cylinder < bq->b_cylinder) {
/*
* Search the second request list for the first
* request at a larger cylinder number. We go
* before that; if there is no such request, we
* go at end.
*/
do {
if (bp->b_cylinder <
bq->b_actf->b_cylinder)
goto insert;
if (bp->b_cylinder ==
bq->b_actf->b_cylinder &&
bp->b_blkno < bq->b_actf->b_blkno)
goto insert;
bq = bq->b_actf;
} while (bq->b_actf);
goto insert; /* after last */
}
bq = bq->b_actf;
}
/*
* No inversions... we will go after the last, and
* be the first request in the second request list.
*/
goto insert;
}
/*
* Request is at/after the current request...
* sort in the first request list.
*/
while (bq->b_actf) {
/*
* We want to go after the current request if there is an
* inversion after it (i.e. it is the end of the first
* request list), or if the next request is a larger cylinder
* than our request.
*/
if (bq->b_actf->b_cylinder < bq->b_cylinder ||
bp->b_cylinder < bq->b_actf->b_cylinder ||
(bp->b_cylinder == bq->b_actf->b_cylinder &&
bp->b_blkno < bq->b_actf->b_blkno))
goto insert;
bq = bq->b_actf;
}
/*
* Neither a second list nor a larger request... we go at the end of
* the first list, which is the same as the end of the whole schebang.
*/
insert: bp->b_actf = bq->b_actf;
bq->b_actf = bp;
}
/*
* Attempt to read a disk label from a device using the indicated stategy
* routine. The label must be partly set up before this: secpercyl and
* anything required in the strategy routine (e.g., sector size) must be
* filled in before calling us. Returns NULL on success and an error
* string on failure.
*/
char *
readdisklabel(dev, strat, lp, dp, bdp)
dev_t dev;
int (*strat)();
register struct disklabel *lp;
struct dos_partition *dp;
struct dkbad *bdp;
{
register struct buf *bp;
struct disklabel *dlp;
char *msg = NULL;
int dospartoff;
int i;
int cyl;
if (lp->d_secperunit == 0)
lp->d_secperunit = 0x1fffffff;
lp->d_npartitions = 1;
if (lp->d_partitions[0].p_size == 0)
lp->d_partitions[0].p_size = 0x1fffffff;
lp->d_partitions[0].p_offset = 0;
bp = geteblk((int)lp->d_secsize);
/* do dos partitions in the process of getting disklabel? */
dospartoff = 0;
cyl = LABELSECTOR / lp->d_secpercyl;
if (dp) {
/* read master boot record */
bp->b_dev = dev;
bp->b_blkno = DOSBBSECTOR;
bp->b_bcount = lp->d_secsize;
bp->b_flags = B_BUSY | B_READ;
bp->b_cylinder = DOSBBSECTOR / lp->d_secpercyl;
(*strat)(bp);
/* if successful, wander through dos partition table */
if (biowait(bp)) {
msg = "dos partition I/O error";
goto done;
} else {
/* XXX how do we check veracity/bounds of this? */
bcopy(bp->b_un.b_addr + DOSPARTOFF, dp,
NDOSPART * sizeof(*dp));
for (i = 0; i < NDOSPART; i++, dp++)
/* is this ours? */
if (dp->dp_size &&
dp->dp_typ == DOSPTYP_386BSD
&& dospartoff == 0) {
/* need sector address for SCSI/IDE,
cylinder for ESDI/ST506/RLL */
dospartoff = dp->dp_start;
cyl = DPCYL(dp->dp_scyl, dp->dp_ssect);
/* update disklabel with details */
lp->d_partitions[0].p_size =
dp->dp_size;
lp->d_partitions[0].p_offset =
dp->dp_start;
lp->d_ntracks = dp->dp_ehd + 1;
lp->d_nsectors = DPSECT(dp->dp_esect);
#ifdef CC_WALL
/* The next statement looks bogus... i runs int 0..3 ??? */
lp->d_subtype |= ((lp->d_subtype & 3)
+ i) | DSTYPE_INDOSPART;
#else /* CC_WALL */
lp->d_subtype |= (lp->d_subtype & 3)
+ i | DSTYPE_INDOSPART;
#endif /* CC_WALL */
lp->d_secpercyl = lp->d_ntracks *
lp->d_nsectors;
}
}
}
/* next, dig out disk label */
bp->b_blkno = dospartoff + LABELSECTOR;
bp->b_dev = dev;
bp->b_bcount = lp->d_secsize;
bp->b_flags = B_BUSY | B_READ;
bp->b_cylinder = cyl;
(*strat)(bp);
if (biowait(bp))
msg = "I/O error";
else for (dlp = (struct disklabel *)bp->b_data;
dlp <= (struct disklabel *)((char *)bp->b_data +
DEV_BSIZE - sizeof(*dlp));
dlp = (struct disklabel *)((char *)dlp + sizeof(long))) {
if (dlp->d_magic != DISKMAGIC || dlp->d_magic2 != DISKMAGIC) {
if (msg == NULL)
msg = "no disk label";
} else if (dlp->d_npartitions > MAXPARTITIONS ||
dkcksum(dlp) != 0)
msg = "disk label corrupted";
else {
*lp = *dlp;
msg = NULL;
break;
}
}
if (msg)
goto done;
/* obtain bad sector table if requested and present */
if (bdp && (lp->d_flags & D_BADSECT)) {
struct dkbad *db;
printf("d_secsize: %ld\n", lp->d_secsize);
i = 0;
do {
/* read a bad sector table */
bp->b_flags = B_BUSY | B_READ;
bp->b_blkno = lp->d_secperunit - lp->d_nsectors + i;
if (lp->d_secsize > DEV_BSIZE)
bp->b_blkno *= lp->d_secsize / DEV_BSIZE;
else
bp->b_blkno /= DEV_BSIZE / lp->d_secsize;
bp->b_bcount = lp->d_secsize;
bp->b_cylinder = lp->d_ncylinders - 1;
(*strat)(bp);
/* if successful, validate, otherwise try another */
if (biowait(bp)) {
msg = "bad sector table I/O error";
} else {
db = (struct dkbad *)(bp->b_un.b_addr);
#define DKBAD_MAGIC 0x4321
if (db->bt_mbz == 0
&& db->bt_flag == DKBAD_MAGIC) {
msg = NULL;
*bdp = *db;
break;
} else
msg = "bad sector table corrupted";
}
} while ((bp->b_flags & B_ERROR) && (i += 2) < 10 &&
i < lp->d_nsectors);
}
done:
bp->b_flags = B_INVAL | B_AGE;
brelse(bp);
return (msg);
}
/*
* Check new disk label for sensibility before setting it.
*/
int
setdisklabel(olp, nlp, openmask)
register struct disklabel *olp, *nlp;
u_long openmask;
{
register i;
register struct partition *opp, *npp;
if (nlp->d_magic != DISKMAGIC || nlp->d_magic2 != DISKMAGIC ||
dkcksum(nlp) != 0)
return (EINVAL);
while ((i = ffs((long)openmask)) != 0) {
i--;
openmask &= ~(1 << i);
if (nlp->d_npartitions <= i)
return (EBUSY);
opp = &olp->d_partitions[i];
npp = &nlp->d_partitions[i];
if (npp->p_offset != opp->p_offset || npp->p_size < opp->p_size)
return (EBUSY);
/*
* Copy internally-set partition information
* if new label doesn't include it. XXX
*/
if (npp->p_fstype == FS_UNUSED && opp->p_fstype != FS_UNUSED) {
npp->p_fstype = opp->p_fstype;
npp->p_fsize = opp->p_fsize;
npp->p_frag = opp->p_frag;
npp->p_cpg = opp->p_cpg;
}
}
nlp->d_checksum = 0;
nlp->d_checksum = dkcksum(nlp);
*olp = *nlp;
return (0);
}
/* encoding of disk minor numbers, should be elsewhere... */
#define dkunit(dev) (minor(dev) >> 3)
#define dkpart(dev) (minor(dev) & 07)
#define dkminor(unit, part) (((unit) << 3) | (part))
/*
* Write disk label back to device after modification.
*/
int
writedisklabel(dev, strat, lp)
dev_t dev;
int (*strat)();
register struct disklabel *lp;
{
struct buf *bp;
struct disklabel *dlp;
int labelpart;
int error = 0;
labelpart = dkpart(dev);
/* XXX this is wrong. But leaving it in is worse. */
#ifndef __FREEBSD__
if (lp->d_partitions[labelpart].p_offset != 0) {
if (lp->d_partitions[0].p_offset != 0)
return (EXDEV); /* not quite right */
labelpart = 0;
}
#endif
bp = geteblk((int)lp->d_secsize);
bp->b_dev = makedev(major(dev), dkminor(dkunit(dev), labelpart));
bp->b_blkno = LABELSECTOR;
bp->b_bcount = lp->d_secsize;
bp->b_flags = B_READ;
(*strat)(bp);
error = biowait(bp);
if (error)
goto done;
for (dlp = (struct disklabel *)bp->b_data;
dlp <= (struct disklabel *)
((char *)bp->b_data + lp->d_secsize - sizeof(*dlp));
dlp = (struct disklabel *)((char *)dlp + sizeof(long))) {
if (dlp->d_magic == DISKMAGIC && dlp->d_magic2 == DISKMAGIC &&
dkcksum(dlp) == 0) {
*dlp = *lp;
bp->b_flags = B_WRITE;
(*strat)(bp);
error = biowait(bp);
goto done;
}
}
error = ESRCH;
done:
brelse(bp);
return (error);
}
/*
* Compute checksum for disk label.
*/
int
dkcksum(lp)
register struct disklabel *lp;
{
register u_short *start, *end;
register u_short sum = 0;
start = (u_short *)lp;
end = (u_short *)&lp->d_partitions[lp->d_npartitions];
while (start < end)
sum ^= *start++;
return (sum);
}
/*
* Disk error is the preface to plaintive error messages
* about failing disk transfers. It prints messages of the form
hp0g: hard error reading fsbn 12345 of 12344-12347 (hp0 bn %d cn %d tn %d sn %d)
* if the offset of the error in the transfer and a disk label
* are both available. blkdone should be -1 if the position of the error
* is unknown; the disklabel pointer may be null from drivers that have not
* been converted to use them. The message is printed with printf
* if pri is LOG_PRINTF, otherwise it uses log at the specified priority.
* The message should be completed (with at least a newline) with printf
* or addlog, respectively. There is no trailing space.
*/
void
diskerr(bp, dname, what, pri, blkdone, lp)
register struct buf *bp;
char *dname, *what;
int pri, blkdone;
register struct disklabel *lp;
{
int unit = dkunit(bp->b_dev), part = dkpart(bp->b_dev);
register void (*pr) __P((const char *, ...));
char partname = 'a' + part;
int sn;
if (pri != LOG_PRINTF) {
log(pri, "");
pr = addlog;
} else
pr = printf;
(*pr)("%s%d%c: %s %sing fsbn ", dname, unit, partname, what,
bp->b_flags & B_READ ? "read" : "writ");
sn = bp->b_blkno;
if (bp->b_bcount <= DEV_BSIZE)
(*pr)("%d", sn);
else {
if (blkdone >= 0) {
sn += blkdone;
(*pr)("%d of ", sn);
}
(*pr)("%d-%d", bp->b_blkno,
bp->b_blkno + (bp->b_bcount - 1) / DEV_BSIZE);
}
if (lp && (blkdone >= 0 || bp->b_bcount <= lp->d_secsize)) {
#ifdef tahoe
sn *= DEV_BSIZE / lp->d_secsize; /* XXX */
#endif
sn += lp->d_partitions[part].p_offset;
(*pr)(" (%s%d bn %d; cn %d", dname, unit, sn,
sn / lp->d_secpercyl);
sn %= lp->d_secpercyl;
(*pr)(" tn %d sn %d)", sn / lp->d_nsectors, sn % lp->d_nsectors);
}
}