312 lines
8.7 KiB
C
312 lines
8.7 KiB
C
/* $NetBSD: disksubr.c,v 1.1 2002/12/09 12:16:21 scw Exp $ */
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/*
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* Copyright (c) 1982, 1986, 1988 Regents of the University of California.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)ufs_disksubr.c 7.16 (Berkeley) 5/4/91
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/buf.h>
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#include <sys/disklabel.h>
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#include <sys/syslog.h>
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/*
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* Attempt to read a disk label from a device
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* using the indicated strategy routine.
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* The label must be partly set up before this:
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* secpercyl, secsize and anything required for a block i/o read
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* operation in the driver's strategy/start routines
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* must be filled in before calling us.
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*
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* If dos partition table requested, attempt to load it and
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* find disklabel inside a DOS partition. Also, if bad block
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* table needed, attempt to extract it as well. Return buffer
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* for use in signalling errors if requested.
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*
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* Returns null on success and an error string on failure.
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*/
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char *
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readdisklabel(dev_t dev, void (*strat)(struct buf *), struct disklabel *lp,
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struct cpu_disklabel *osdep)
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{
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struct buf *bp;
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struct disklabel *dlp;
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struct dkbad *bdp;
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char *msg = NULL;
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int i;
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/* minimal requirements for archtypal disk label */
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if (lp->d_secsize == 0)
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lp->d_secsize = DEV_BSIZE;
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if (lp->d_secperunit == 0)
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lp->d_secperunit = 0x1fffffff;
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lp->d_npartitions = RAW_PART + 1;
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if (lp->d_partitions[RAW_PART].p_size == 0)
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lp->d_partitions[RAW_PART].p_size =
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lp->d_secperunit * (lp->d_secsize / DEV_BSIZE);
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lp->d_partitions[RAW_PART].p_offset = 0;
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/* get a buffer and initialize it */
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bp = geteblk((int)lp->d_secsize);
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/* next, dig out disk label */
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bp->b_dev = dev;
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bp->b_blkno = LABELSECTOR;
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bp->b_cylinder = 0;
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bp->b_bcount = lp->d_secsize;
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bp->b_flags |= B_READ;
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(*strat)(bp);
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/* if successful, locate disk label within block and validate */
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if (biowait(bp)) {
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msg = "disk label I/O error";
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goto done;
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}
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for (dlp = (struct disklabel *)bp->b_data;
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dlp <= (struct disklabel *)(bp->b_data + lp->d_secsize - sizeof(*dlp));
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dlp = (struct disklabel *)((char *)dlp + sizeof(long))) {
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if (dlp->d_magic != DISKMAGIC || dlp->d_magic2 != DISKMAGIC) {
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if (msg == NULL)
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msg = "no disk label";
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} else if (dlp->d_npartitions > MAXPARTITIONS ||
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dkcksum(dlp) != 0)
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msg = "disk label corrupted";
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else {
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*lp = *dlp;
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msg = NULL;
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break;
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}
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}
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if (msg)
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goto done;
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/* obtain bad sector table if requested and present */
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if (osdep && (lp->d_flags & D_BADSECT)) {
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struct dkbad *db;
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bdp = &osdep->bad;
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i = 0;
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do {
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/* read a bad sector table */
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bp->b_flags &= ~(B_DONE);
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bp->b_flags |= B_READ;
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bp->b_blkno = lp->d_secperunit - lp->d_nsectors + i;
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if (lp->d_secsize > DEV_BSIZE)
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bp->b_blkno *= lp->d_secsize / DEV_BSIZE;
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else
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bp->b_blkno /= DEV_BSIZE / lp->d_secsize;
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bp->b_bcount = lp->d_secsize;
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bp->b_cylinder = lp->d_ncylinders - 1;
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(*strat)(bp);
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/* if successful, validate, otherwise try another */
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if (biowait(bp)) {
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msg = "bad sector table I/O error";
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} else {
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db = (struct dkbad *)(bp->b_data);
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#define DKBAD_MAGIC 0x4321
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if (db->bt_mbz == 0
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&& db->bt_flag == DKBAD_MAGIC) {
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msg = NULL;
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*bdp = *db;
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break;
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} else
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msg = "bad sector table corrupted";
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}
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} while ((bp->b_flags & B_ERROR) && (i += 2) < 10 &&
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i < lp->d_nsectors);
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}
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done:
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bp->b_flags |= B_INVAL;
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brelse(bp);
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return (msg);
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}
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/*
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* Check new disk label for sensibility before setting it.
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*/
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int
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setdisklabel(struct disklabel *olp, struct disklabel *nlp, u_long openmask,
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struct cpu_disklabel *osdep)
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{
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int i;
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struct partition *opp, *npp;
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/* sanity clause */
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if (nlp->d_secpercyl == 0 || nlp->d_secsize == 0 ||
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(nlp->d_secsize % DEV_BSIZE) != 0)
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return(EINVAL);
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/* special case to allow disklabel to be invalidated */
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if (nlp->d_magic == 0xffffffff) {
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*olp = *nlp;
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return (0);
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}
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if (nlp->d_magic != DISKMAGIC || nlp->d_magic2 != DISKMAGIC ||
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dkcksum(nlp) != 0)
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return (EINVAL);
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while (openmask != 0) {
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i = ffs(openmask) - 1;
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openmask &= ~(1 << i);
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if (nlp->d_npartitions <= i)
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return (EBUSY);
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opp = &olp->d_partitions[i];
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npp = &nlp->d_partitions[i];
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if (npp->p_offset != opp->p_offset || npp->p_size < opp->p_size)
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return (EBUSY);
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/*
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* Copy internally-set partition information
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* if new label doesn't include it. XXX
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*/
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if (npp->p_fstype == FS_UNUSED && opp->p_fstype != FS_UNUSED) {
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npp->p_fstype = opp->p_fstype;
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npp->p_fsize = opp->p_fsize;
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npp->p_frag = opp->p_frag;
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npp->p_cpg = opp->p_cpg;
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}
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}
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nlp->d_checksum = 0;
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nlp->d_checksum = dkcksum(nlp);
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*olp = *nlp;
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return (0);
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}
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/*
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* Write disk label back to device after modification.
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*/
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int
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writedisklabel(dev_t dev, void (*strat)(struct buf *), struct disklabel *lp,
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struct cpu_disklabel *osdep)
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{
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struct buf *bp;
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struct disklabel *dlp;
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int error;
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#ifdef maybe
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/* disklabel in appropriate location? */
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if (lp->d_partitions[2].p_offset != 0
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&& lp->d_partitions[2].p_offset != dospartoff) {
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error = EXDEV;
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goto done;
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}
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#endif
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/* get a buffer and initialize it */
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bp = geteblk((int)lp->d_secsize);
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bp->b_dev = dev;
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bp->b_blkno = LABELSECTOR;
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bp->b_cylinder = 0;
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bp->b_bcount = lp->d_secsize;
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bp->b_flags |= B_READ;
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(*strat)(bp);
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/* if successful, locate disk label within block and validate */
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if ((error = biowait(bp)) != 0)
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goto done;
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for (dlp = (struct disklabel *)bp->b_data;
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dlp <= (struct disklabel *)(bp->b_data + lp->d_secsize - sizeof(*dlp));
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dlp = (struct disklabel *)((char *)dlp + sizeof(long))) {
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if (dlp->d_magic == DISKMAGIC && dlp->d_magic2 == DISKMAGIC &&
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dkcksum(dlp) == 0) {
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*dlp = *lp;
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bp->b_flags = B_BUSY | B_WRITE;
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(*strat)(bp);
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error = biowait(bp);
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goto done;
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}
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}
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error = ESRCH;
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done:
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brelse(bp);
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return (error);
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}
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/*
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* Determine the size of the transfer, and make sure it is
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* within the boundaries of the partition. Adjust transfer
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* if needed, and signal errors or early completion.
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*/
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int
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bounds_check_with_label(struct buf *bp, struct disklabel *lp, int wlabel)
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{
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struct partition *p = lp->d_partitions + DISKPART(bp->b_dev);
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int labelsector = lp->d_partitions[RAW_PART].p_offset + LABELSECTOR;
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int sz;
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sz = howmany(bp->b_bcount, lp->d_secsize);
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if (bp->b_blkno + sz > p->p_size) {
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sz = p->p_size - bp->b_blkno;
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if (sz == 0) {
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/* If exactly at end of disk, return EOF. */
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bp->b_resid = bp->b_bcount;
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goto done;
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}
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if (sz < 0) {
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/* If past end of disk, return EINVAL. */
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bp->b_error = EINVAL;
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goto bad;
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}
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/* Otherwise, truncate request. */
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bp->b_bcount = sz << DEV_BSHIFT;
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}
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/* Overwriting disk label? */
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if (bp->b_blkno + p->p_offset <= labelsector &&
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#if LABELSECTOR != 0
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bp->b_blkno + p->p_offset + sz > labelsector &&
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#endif
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(bp->b_flags & B_READ) == 0 && !wlabel) {
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bp->b_error = EROFS;
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goto bad;
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}
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/* calculate cylinder for disksort to order transfers with */
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bp->b_cylinder = (bp->b_blkno + p->p_offset) /
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(lp->d_secsize / DEV_BSIZE) / lp->d_secpercyl;
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return (1);
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bad:
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bp->b_flags |= B_ERROR;
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done:
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return (0);
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}
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