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Annotation of Net2/ufs/ufs_disksubr.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1982, 1986, 1988 Regents of the University of California.
        !             3:  * 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:  *     @(#)ufs_disksubr.c      7.16 (Berkeley) 5/4/91
        !            34:  */
        !            35: 
        !            36: #include "param.h"
        !            37: #include "systm.h"
        !            38: #include "buf.h"
        !            39: #include "disklabel.h"
        !            40: #include "syslog.h"
        !            41: 
        !            42: /*
        !            43:  * Seek sort for disks.  We depend on the driver
        !            44:  * which calls us using b_resid as the current cylinder number.
        !            45:  *
        !            46:  * The argument dp structure holds a b_actf activity chain pointer
        !            47:  * on which we keep two queues, sorted in ascending cylinder order.
        !            48:  * The first queue holds those requests which are positioned after
        !            49:  * the current cylinder (in the first request); the second holds
        !            50:  * requests which came in after their cylinder number was passed.
        !            51:  * Thus we implement a one way scan, retracting after reaching the
        !            52:  * end of the drive to the first request on the second queue,
        !            53:  * at which time it becomes the first queue.
        !            54:  *
        !            55:  * A one-way scan is natural because of the way UNIX read-ahead
        !            56:  * blocks are allocated.
        !            57:  */
        !            58: 
        !            59: #define        b_cylin b_resid
        !            60: 
        !            61: disksort(dp, bp)
        !            62:        register struct buf *dp, *bp;
        !            63: {
        !            64:        register struct buf *ap;
        !            65: 
        !            66:        /*
        !            67:         * If nothing on the activity queue, then
        !            68:         * we become the only thing.
        !            69:         */
        !            70:        ap = dp->b_actf;
        !            71:        if(ap == NULL) {
        !            72:                dp->b_actf = bp;
        !            73:                dp->b_actl = bp;
        !            74:                bp->av_forw = NULL;
        !            75:                return;
        !            76:        }
        !            77:        /*
        !            78:         * If we lie after the first (currently active)
        !            79:         * request, then we must locate the second request list
        !            80:         * and add ourselves to it.
        !            81:         */
        !            82:        if (bp->b_cylin < ap->b_cylin) {
        !            83:                while (ap->av_forw) {
        !            84:                        /*
        !            85:                         * Check for an ``inversion'' in the
        !            86:                         * normally ascending cylinder numbers,
        !            87:                         * indicating the start of the second request list.
        !            88:                         */
        !            89:                        if (ap->av_forw->b_cylin < ap->b_cylin) {
        !            90:                                /*
        !            91:                                 * Search the second request list
        !            92:                                 * for the first request at a larger
        !            93:                                 * cylinder number.  We go before that;
        !            94:                                 * if there is no such request, we go at end.
        !            95:                                 */
        !            96:                                do {
        !            97:                                        if (bp->b_cylin < ap->av_forw->b_cylin)
        !            98:                                                goto insert;
        !            99:                                        if (bp->b_cylin == ap->av_forw->b_cylin &&
        !           100:                                            bp->b_blkno < ap->av_forw->b_blkno)
        !           101:                                                goto insert;
        !           102:                                        ap = ap->av_forw;
        !           103:                                } while (ap->av_forw);
        !           104:                                goto insert;            /* after last */
        !           105:                        }
        !           106:                        ap = ap->av_forw;
        !           107:                }
        !           108:                /*
        !           109:                 * No inversions... we will go after the last, and
        !           110:                 * be the first request in the second request list.
        !           111:                 */
        !           112:                goto insert;
        !           113:        }
        !           114:        /*
        !           115:         * Request is at/after the current request...
        !           116:         * sort in the first request list.
        !           117:         */
        !           118:        while (ap->av_forw) {
        !           119:                /*
        !           120:                 * We want to go after the current request
        !           121:                 * if there is an inversion after it (i.e. it is
        !           122:                 * the end of the first request list), or if
        !           123:                 * the next request is a larger cylinder than our request.
        !           124:                 */
        !           125:                if (ap->av_forw->b_cylin < ap->b_cylin ||
        !           126:                    bp->b_cylin < ap->av_forw->b_cylin ||
        !           127:                    (bp->b_cylin == ap->av_forw->b_cylin &&
        !           128:                    bp->b_blkno < ap->av_forw->b_blkno))
        !           129:                        goto insert;
        !           130:                ap = ap->av_forw;
        !           131:        }
        !           132:        /*
        !           133:         * Neither a second list nor a larger
        !           134:         * request... we go at the end of the first list,
        !           135:         * which is the same as the end of the whole schebang.
        !           136:         */
        !           137: insert:
        !           138:        bp->av_forw = ap->av_forw;
        !           139:        ap->av_forw = bp;
        !           140:        if (ap == dp->b_actl)
        !           141:                dp->b_actl = bp;
        !           142: }
        !           143: 
        !           144: /*
        !           145:  * Attempt to read a disk label from a device
        !           146:  * using the indicated stategy routine.
        !           147:  * The label must be partly set up before this:
        !           148:  * secpercyl and anything required in the strategy routine
        !           149:  * (e.g., sector size) must be filled in before calling us.
        !           150:  * Returns null on success and an error string on failure.
        !           151:  */
        !           152: char *
        !           153: readdisklabel(dev, strat, lp)
        !           154:        dev_t dev;
        !           155:        int (*strat)();
        !           156:        register struct disklabel *lp;
        !           157: {
        !           158:        register struct buf *bp;
        !           159:        struct disklabel *dlp;
        !           160:        char *msg = NULL;
        !           161: 
        !           162:        if (lp->d_secperunit == 0)
        !           163:                lp->d_secperunit = 0x1fffffff;
        !           164:        lp->d_npartitions = 1;
        !           165:        if (lp->d_partitions[0].p_size == 0)
        !           166:                lp->d_partitions[0].p_size = 0x1fffffff;
        !           167:        lp->d_partitions[0].p_offset = 0;
        !           168: 
        !           169:        bp = geteblk((int)lp->d_secsize);
        !           170:        bp->b_dev = dev;
        !           171:        bp->b_blkno = LABELSECTOR;
        !           172:        bp->b_bcount = lp->d_secsize;
        !           173:        bp->b_flags = B_BUSY | B_READ;
        !           174:        bp->b_cylin = LABELSECTOR / lp->d_secpercyl;
        !           175:        (*strat)(bp);
        !           176:        if (biowait(bp)) {
        !           177:                msg = "I/O error";
        !           178:        } else for (dlp = (struct disklabel *)bp->b_un.b_addr;
        !           179:            dlp <= (struct disklabel *)(bp->b_un.b_addr+DEV_BSIZE-sizeof(*dlp));
        !           180:            dlp = (struct disklabel *)((char *)dlp + sizeof(long))) {
        !           181:                if (dlp->d_magic != DISKMAGIC || dlp->d_magic2 != DISKMAGIC) {
        !           182:                        if (msg == NULL)
        !           183:                                msg = "no disk label";
        !           184:                } else if (dlp->d_npartitions > MAXPARTITIONS ||
        !           185:                           dkcksum(dlp) != 0)
        !           186:                        msg = "disk label corrupted";
        !           187:                else {
        !           188:                        *lp = *dlp;
        !           189:                        msg = NULL;
        !           190:                        break;
        !           191:                }
        !           192:        }
        !           193:        bp->b_flags = B_INVAL | B_AGE;
        !           194:        brelse(bp);
        !           195:        return (msg);
        !           196: }
        !           197: 
        !           198: /*
        !           199:  * Check new disk label for sensibility
        !           200:  * before setting it.
        !           201:  */
        !           202: setdisklabel(olp, nlp, openmask)
        !           203:        register struct disklabel *olp, *nlp;
        !           204:        u_long openmask;
        !           205: {
        !           206:        register i;
        !           207:        register struct partition *opp, *npp;
        !           208: 
        !           209:        if (nlp->d_magic != DISKMAGIC || nlp->d_magic2 != DISKMAGIC ||
        !           210:            dkcksum(nlp) != 0)
        !           211:                return (EINVAL);
        !           212:        while ((i = ffs((long)openmask)) != 0) {
        !           213:                i--;
        !           214:                openmask &= ~(1 << i);
        !           215:                if (nlp->d_npartitions <= i)
        !           216:                        return (EBUSY);
        !           217:                opp = &olp->d_partitions[i];
        !           218:                npp = &nlp->d_partitions[i];
        !           219:                if (npp->p_offset != opp->p_offset || npp->p_size < opp->p_size)
        !           220:                        return (EBUSY);
        !           221:                /*
        !           222:                 * Copy internally-set partition information
        !           223:                 * if new label doesn't include it.             XXX
        !           224:                 */
        !           225:                if (npp->p_fstype == FS_UNUSED && opp->p_fstype != FS_UNUSED) {
        !           226:                        npp->p_fstype = opp->p_fstype;
        !           227:                        npp->p_fsize = opp->p_fsize;
        !           228:                        npp->p_frag = opp->p_frag;
        !           229:                        npp->p_cpg = opp->p_cpg;
        !           230:                }
        !           231:        }
        !           232:        nlp->d_checksum = 0;
        !           233:        nlp->d_checksum = dkcksum(nlp);
        !           234:        *olp = *nlp;
        !           235:        return (0);
        !           236: }
        !           237: 
        !           238: /* encoding of disk minor numbers, should be elsewhere... */
        !           239: #define dkunit(dev)            (minor(dev) >> 3)
        !           240: #define dkpart(dev)            (minor(dev) & 07)
        !           241: #define dkminor(unit, part)    (((unit) << 3) | (part))
        !           242: 
        !           243: /*
        !           244:  * Write disk label back to device after modification.
        !           245:  */
        !           246: writedisklabel(dev, strat, lp)
        !           247:        dev_t dev;
        !           248:        int (*strat)();
        !           249:        register struct disklabel *lp;
        !           250: {
        !           251:        struct buf *bp;
        !           252:        struct disklabel *dlp;
        !           253:        int labelpart;
        !           254:        int error = 0;
        !           255: 
        !           256:        labelpart = dkpart(dev);
        !           257:        if (lp->d_partitions[labelpart].p_offset != 0) {
        !           258:                if (lp->d_partitions[0].p_offset != 0)
        !           259:                        return (EXDEV);                 /* not quite right */
        !           260:                labelpart = 0;
        !           261:        }
        !           262:        bp = geteblk((int)lp->d_secsize);
        !           263:        bp->b_dev = makedev(major(dev), dkminor(dkunit(dev), labelpart));
        !           264:        bp->b_blkno = LABELSECTOR;
        !           265:        bp->b_bcount = lp->d_secsize;
        !           266:        bp->b_flags = B_READ;
        !           267:        (*strat)(bp);
        !           268:        if (error = biowait(bp))
        !           269:                goto done;
        !           270:        for (dlp = (struct disklabel *)bp->b_un.b_addr;
        !           271:            dlp <= (struct disklabel *)
        !           272:              (bp->b_un.b_addr + lp->d_secsize - sizeof(*dlp));
        !           273:            dlp = (struct disklabel *)((char *)dlp + sizeof(long))) {
        !           274:                if (dlp->d_magic == DISKMAGIC && dlp->d_magic2 == DISKMAGIC &&
        !           275:                    dkcksum(dlp) == 0) {
        !           276:                        *dlp = *lp;
        !           277:                        bp->b_flags = B_WRITE;
        !           278:                        (*strat)(bp);
        !           279:                        error = biowait(bp);
        !           280:                        goto done;
        !           281:                }
        !           282:        }
        !           283:        error = ESRCH;
        !           284: done:
        !           285:        brelse(bp);
        !           286:        return (error);
        !           287: }
        !           288: 
        !           289: /*
        !           290:  * Compute checksum for disk label.
        !           291:  */
        !           292: dkcksum(lp)
        !           293:        register struct disklabel *lp;
        !           294: {
        !           295:        register u_short *start, *end;
        !           296:        register u_short sum = 0;
        !           297: 
        !           298:        start = (u_short *)lp;
        !           299:        end = (u_short *)&lp->d_partitions[lp->d_npartitions];
        !           300:        while (start < end)
        !           301:                sum ^= *start++;
        !           302:        return (sum);
        !           303: }
        !           304: 
        !           305: /*
        !           306:  * Disk error is the preface to plaintive error messages
        !           307:  * about failing disk transfers.  It prints messages of the form
        !           308: 
        !           309: hp0g: hard error reading fsbn 12345 of 12344-12347 (hp0 bn %d cn %d tn %d sn %d)
        !           310: 
        !           311:  * if the offset of the error in the transfer and a disk label
        !           312:  * are both available.  blkdone should be -1 if the position of the error
        !           313:  * is unknown; the disklabel pointer may be null from drivers that have not
        !           314:  * been converted to use them.  The message is printed with printf
        !           315:  * if pri is LOG_PRINTF, otherwise it uses log at the specified priority.
        !           316:  * The message should be completed (with at least a newline) with printf
        !           317:  * or addlog, respectively.  There is no trailing space.
        !           318:  */
        !           319: diskerr(bp, dname, what, pri, blkdone, lp)
        !           320:        register struct buf *bp;
        !           321:        char *dname, *what;
        !           322:        int pri, blkdone;
        !           323:        register struct disklabel *lp;
        !           324: {
        !           325:        int unit = dkunit(bp->b_dev), part = dkpart(bp->b_dev);
        !           326:        register void (*pr) __P((const char *, ...));
        !           327:        char partname = 'a' + part;
        !           328:        int sn;
        !           329: 
        !           330:        if (pri != LOG_PRINTF) {
        !           331:                log(pri, "");
        !           332:                pr = addlog;
        !           333:        } else
        !           334:                pr = printf;
        !           335:        (*pr)("%s%d%c: %s %sing fsbn ", dname, unit, partname, what,
        !           336:            bp->b_flags & B_READ ? "read" : "writ");
        !           337:        sn = bp->b_blkno;
        !           338:        if (bp->b_bcount <= DEV_BSIZE)
        !           339:                (*pr)("%d", sn);
        !           340:        else {
        !           341:                if (blkdone >= 0) {
        !           342:                        sn += blkdone;
        !           343:                        (*pr)("%d of ", sn);
        !           344:                }
        !           345:                (*pr)("%d-%d", bp->b_blkno,
        !           346:                    bp->b_blkno + (bp->b_bcount - 1) / DEV_BSIZE);
        !           347:        }
        !           348:        if (lp && (blkdone >= 0 || bp->b_bcount <= lp->d_secsize)) {
        !           349: #ifdef tahoe
        !           350:                sn *= DEV_BSIZE / lp->d_secsize;                /* XXX */
        !           351: #endif
        !           352:                sn += lp->d_partitions[part].p_offset;
        !           353:                (*pr)(" (%s%d bn %d; cn %d", dname, unit, sn,
        !           354:                    sn / lp->d_secpercyl);
        !           355:                sn %= lp->d_secpercyl;
        !           356:                (*pr)(" tn %d sn %d)", sn / lp->d_nsectors, sn % lp->d_nsectors);
        !           357:        }
        !           358: }

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