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Annotation of 43BSDReno/sys/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 is only permitted until one year after the first shipment
        !             6:  * of 4.4BSD by the Regents.  Otherwise, redistribution and use in source and
        !             7:  * binary forms are permitted provided that: (1) source distributions retain
        !             8:  * this entire copyright notice and comment, and (2) distributions including
        !             9:  * binaries display the following acknowledgement:  This product includes
        !            10:  * software developed by the University of California, Berkeley and its
        !            11:  * contributors'' in the documentation or other materials provided with the
        !            12:  * distribution and in all advertising materials mentioning features or use
        !            13:  * of this software.  Neither the name of the University nor the names of
        !            14:  * its contributors may be used to endorse or promote products derived from
        !            15:  * this software without specific prior written permission.
        !            16:  * THIS SOFTWARE IS PROVIDED AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
        !            17:  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
        !            18:  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
        !            19:  *
        !            20:  *     @(#)ufs_disksubr.c      7.14 (Berkeley) 6/28/90
        !            21:  */
        !            22: 
        !            23: #include "param.h"
        !            24: #include "systm.h"
        !            25: #include "buf.h"
        !            26: #include "disklabel.h"
        !            27: #include "syslog.h"
        !            28: #include "user.h"
        !            29: 
        !            30: /*
        !            31:  * Seek sort for disks.  We depend on the driver
        !            32:  * which calls us using b_resid as the current cylinder number.
        !            33:  *
        !            34:  * The argument dp structure holds a b_actf activity chain pointer
        !            35:  * on which we keep two queues, sorted in ascending cylinder order.
        !            36:  * The first queue holds those requests which are positioned after
        !            37:  * the current cylinder (in the first request); the second holds
        !            38:  * requests which came in after their cylinder number was passed.
        !            39:  * Thus we implement a one way scan, retracting after reaching the
        !            40:  * end of the drive to the first request on the second queue,
        !            41:  * at which time it becomes the first queue.
        !            42:  *
        !            43:  * A one-way scan is natural because of the way UNIX read-ahead
        !            44:  * blocks are allocated.
        !            45:  */
        !            46: 
        !            47: #define        b_cylin b_resid
        !            48: 
        !            49: disksort(dp, bp)
        !            50:        register struct buf *dp, *bp;
        !            51: {
        !            52:        register struct buf *ap;
        !            53: 
        !            54:        /*
        !            55:         * If nothing on the activity queue, then
        !            56:         * we become the only thing.
        !            57:         */
        !            58:        ap = dp->b_actf;
        !            59:        if(ap == NULL) {
        !            60:                dp->b_actf = bp;
        !            61:                dp->b_actl = bp;
        !            62:                bp->av_forw = NULL;
        !            63:                return;
        !            64:        }
        !            65:        /*
        !            66:         * If we lie after the first (currently active)
        !            67:         * request, then we must locate the second request list
        !            68:         * and add ourselves to it.
        !            69:         */
        !            70:        if (bp->b_cylin < ap->b_cylin) {
        !            71:                while (ap->av_forw) {
        !            72:                        /*
        !            73:                         * Check for an ``inversion'' in the
        !            74:                         * normally ascending cylinder numbers,
        !            75:                         * indicating the start of the second request list.
        !            76:                         */
        !            77:                        if (ap->av_forw->b_cylin < ap->b_cylin) {
        !            78:                                /*
        !            79:                                 * Search the second request list
        !            80:                                 * for the first request at a larger
        !            81:                                 * cylinder number.  We go before that;
        !            82:                                 * if there is no such request, we go at end.
        !            83:                                 */
        !            84:                                do {
        !            85:                                        if (bp->b_cylin < ap->av_forw->b_cylin)
        !            86:                                                goto insert;
        !            87:                                        if (bp->b_cylin == ap->av_forw->b_cylin &&
        !            88:                                            bp->b_blkno < ap->av_forw->b_blkno)
        !            89:                                                goto insert;
        !            90:                                        ap = ap->av_forw;
        !            91:                                } while (ap->av_forw);
        !            92:                                goto insert;            /* after last */
        !            93:                        }
        !            94:                        ap = ap->av_forw;
        !            95:                }
        !            96:                /*
        !            97:                 * No inversions... we will go after the last, and
        !            98:                 * be the first request in the second request list.
        !            99:                 */
        !           100:                goto insert;
        !           101:        }
        !           102:        /*
        !           103:         * Request is at/after the current request...
        !           104:         * sort in the first request list.
        !           105:         */
        !           106:        while (ap->av_forw) {
        !           107:                /*
        !           108:                 * We want to go after the current request
        !           109:                 * if there is an inversion after it (i.e. it is
        !           110:                 * the end of the first request list), or if
        !           111:                 * the next request is a larger cylinder than our request.
        !           112:                 */
        !           113:                if (ap->av_forw->b_cylin < ap->b_cylin ||
        !           114:                    bp->b_cylin < ap->av_forw->b_cylin ||
        !           115:                    (bp->b_cylin == ap->av_forw->b_cylin &&
        !           116:                    bp->b_blkno < ap->av_forw->b_blkno))
        !           117:                        goto insert;
        !           118:                ap = ap->av_forw;
        !           119:        }
        !           120:        /*
        !           121:         * Neither a second list nor a larger
        !           122:         * request... we go at the end of the first list,
        !           123:         * which is the same as the end of the whole schebang.
        !           124:         */
        !           125: insert:
        !           126:        bp->av_forw = ap->av_forw;
        !           127:        ap->av_forw = bp;
        !           128:        if (ap == dp->b_actl)
        !           129:                dp->b_actl = bp;
        !           130: }
        !           131: 
        !           132: /*
        !           133:  * Attempt to read a disk label from a device
        !           134:  * using the indicated stategy routine.
        !           135:  * The label must be partly set up before this:
        !           136:  * secpercyl and anything required in the strategy routine
        !           137:  * (e.g., sector size) must be filled in before calling us.
        !           138:  * Returns null on success and an error string on failure.
        !           139:  */
        !           140: char *
        !           141: readdisklabel(dev, strat, lp)
        !           142:        dev_t dev;
        !           143:        int (*strat)();
        !           144:        register struct disklabel *lp;
        !           145: {
        !           146:        register struct buf *bp;
        !           147:        struct disklabel *dlp;
        !           148:        char *msg = NULL;
        !           149: 
        !           150:        if (lp->d_secperunit == 0)
        !           151:                lp->d_secperunit = 0x1fffffff;
        !           152:        lp->d_npartitions = 1;
        !           153:        if (lp->d_partitions[0].p_size == 0)
        !           154:                lp->d_partitions[0].p_size = 0x1fffffff;
        !           155:        lp->d_partitions[0].p_offset = 0;
        !           156: 
        !           157:        bp = geteblk((int)lp->d_secsize);
        !           158:        bp->b_dev = dev;
        !           159:        bp->b_blkno = LABELSECTOR;
        !           160:        bp->b_bcount = lp->d_secsize;
        !           161:        bp->b_flags = B_BUSY | B_READ;
        !           162:        bp->b_cylin = LABELSECTOR / lp->d_secpercyl;
        !           163:        (*strat)(bp);
        !           164:        if (biowait(bp)) {
        !           165:                msg = "I/O error";
        !           166:        } else for (dlp = (struct disklabel *)bp->b_un.b_addr;
        !           167:            dlp <= (struct disklabel *)(bp->b_un.b_addr+DEV_BSIZE-sizeof(*dlp));
        !           168:            dlp = (struct disklabel *)((char *)dlp + sizeof(long))) {
        !           169:                if (dlp->d_magic != DISKMAGIC || dlp->d_magic2 != DISKMAGIC) {
        !           170:                        if (msg == NULL)
        !           171:                                msg = "no disk label";
        !           172:                } else if (dlp->d_npartitions > MAXPARTITIONS ||
        !           173:                           dkcksum(dlp) != 0)
        !           174:                        msg = "disk label corrupted";
        !           175:                else {
        !           176:                        *lp = *dlp;
        !           177:                        msg = NULL;
        !           178:                        break;
        !           179:                }
        !           180:        }
        !           181:        bp->b_flags = B_INVAL | B_AGE;
        !           182:        brelse(bp);
        !           183:        return (msg);
        !           184: }
        !           185: 
        !           186: /*
        !           187:  * Check new disk label for sensibility
        !           188:  * before setting it.
        !           189:  */
        !           190: setdisklabel(olp, nlp, openmask)
        !           191:        register struct disklabel *olp, *nlp;
        !           192:        u_long openmask;
        !           193: {
        !           194:        register i;
        !           195:        register struct partition *opp, *npp;
        !           196: 
        !           197:        if (nlp->d_magic != DISKMAGIC || nlp->d_magic2 != DISKMAGIC ||
        !           198:            dkcksum(nlp) != 0)
        !           199:                return (EINVAL);
        !           200:        while ((i = ffs((long)openmask)) != 0) {
        !           201:                i--;
        !           202:                openmask &= ~(1 << i);
        !           203:                if (nlp->d_npartitions <= i)
        !           204:                        return (EBUSY);
        !           205:                opp = &olp->d_partitions[i];
        !           206:                npp = &nlp->d_partitions[i];
        !           207:                if (npp->p_offset != opp->p_offset || npp->p_size < opp->p_size)
        !           208:                        return (EBUSY);
        !           209:                /*
        !           210:                 * Copy internally-set partition information
        !           211:                 * if new label doesn't include it.             XXX
        !           212:                 */
        !           213:                if (npp->p_fstype == FS_UNUSED && opp->p_fstype != FS_UNUSED) {
        !           214:                        npp->p_fstype = opp->p_fstype;
        !           215:                        npp->p_fsize = opp->p_fsize;
        !           216:                        npp->p_frag = opp->p_frag;
        !           217:                        npp->p_cpg = opp->p_cpg;
        !           218:                }
        !           219:        }
        !           220:        nlp->d_checksum = 0;
        !           221:        nlp->d_checksum = dkcksum(nlp);
        !           222:        *olp = *nlp;
        !           223:        return (0);
        !           224: }
        !           225: 
        !           226: /* encoding of disk minor numbers, should be elsewhere... */
        !           227: #define dkunit(dev)            (minor(dev) >> 3)
        !           228: #define dkpart(dev)            (minor(dev) & 07)
        !           229: #define dkminor(unit, part)    (((unit) << 3) | (part))
        !           230: 
        !           231: /*
        !           232:  * Write disk label back to device after modification.
        !           233:  */
        !           234: writedisklabel(dev, strat, lp)
        !           235:        dev_t dev;
        !           236:        int (*strat)();
        !           237:        register struct disklabel *lp;
        !           238: {
        !           239:        struct buf *bp;
        !           240:        struct disklabel *dlp;
        !           241:        int labelpart;
        !           242:        int error = 0;
        !           243: 
        !           244:        labelpart = dkpart(dev);
        !           245:        if (lp->d_partitions[labelpart].p_offset != 0) {
        !           246:                if (lp->d_partitions[0].p_offset != 0)
        !           247:                        return (EXDEV);                 /* not quite right */
        !           248:                labelpart = 0;
        !           249:        }
        !           250:        bp = geteblk((int)lp->d_secsize);
        !           251:        bp->b_dev = makedev(major(dev), dkminor(dkunit(dev), labelpart));
        !           252:        bp->b_blkno = LABELSECTOR;
        !           253:        bp->b_bcount = lp->d_secsize;
        !           254:        bp->b_flags = B_READ;
        !           255:        (*strat)(bp);
        !           256:        if (error = biowait(bp))
        !           257:                goto done;
        !           258:        for (dlp = (struct disklabel *)bp->b_un.b_addr;
        !           259:            dlp <= (struct disklabel *)
        !           260:              (bp->b_un.b_addr + lp->d_secsize - sizeof(*dlp));
        !           261:            dlp = (struct disklabel *)((char *)dlp + sizeof(long))) {
        !           262:                if (dlp->d_magic == DISKMAGIC && dlp->d_magic2 == DISKMAGIC &&
        !           263:                    dkcksum(dlp) == 0) {
        !           264:                        *dlp = *lp;
        !           265:                        bp->b_flags = B_WRITE;
        !           266:                        (*strat)(bp);
        !           267:                        error = biowait(bp);
        !           268:                        goto done;
        !           269:                }
        !           270:        }
        !           271:        error = ESRCH;
        !           272: done:
        !           273:        brelse(bp);
        !           274:        return (error);
        !           275: }
        !           276: 
        !           277: /*
        !           278:  * Compute checksum for disk label.
        !           279:  */
        !           280: dkcksum(lp)
        !           281:        register struct disklabel *lp;
        !           282: {
        !           283:        register u_short *start, *end;
        !           284:        register u_short sum = 0;
        !           285: 
        !           286:        start = (u_short *)lp;
        !           287:        end = (u_short *)&lp->d_partitions[lp->d_npartitions];
        !           288:        while (start < end)
        !           289:                sum ^= *start++;
        !           290:        return (sum);
        !           291: }
        !           292: 
        !           293: /*
        !           294:  * Disk error is the preface to plaintive error messages
        !           295:  * about failing disk transfers.  It prints messages of the form
        !           296: 
        !           297: hp0g: hard error reading fsbn 12345 of 12344-12347 (hp0 bn %d cn %d tn %d sn %d)
        !           298: 
        !           299:  * if the offset of the error in the transfer and a disk label
        !           300:  * are both available.  blkdone should be -1 if the position of the error
        !           301:  * is unknown; the disklabel pointer may be null from drivers that have not
        !           302:  * been converted to use them.  The message is printed with printf
        !           303:  * if pri is LOG_PRINTF, otherwise it uses log at the specified priority.
        !           304:  * The message should be completed (with at least a newline) with printf
        !           305:  * or addlog, respectively.  There is no trailing space.
        !           306:  */
        !           307: diskerr(bp, dname, what, pri, blkdone, lp)
        !           308:        register struct buf *bp;
        !           309:        char *dname, *what;
        !           310:        int pri, blkdone;
        !           311:        register struct disklabel *lp;
        !           312: {
        !           313:        int unit = dkunit(bp->b_dev), part = dkpart(bp->b_dev);
        !           314:        register int (*pr)(), sn;
        !           315:        char partname = 'a' + part;
        !           316:        extern printf(), addlog();
        !           317: 
        !           318:        if (pri != LOG_PRINTF) {
        !           319:                log(pri, "");
        !           320:                pr = addlog;
        !           321:        } else
        !           322:                pr = printf;
        !           323:        (*pr)("%s%d%c: %s %sing fsbn ", dname, unit, partname, what,
        !           324:            bp->b_flags & B_READ ? "read" : "writ");
        !           325:        sn = bp->b_blkno;
        !           326:        if (bp->b_bcount <= DEV_BSIZE)
        !           327:                (*pr)("%d", sn);
        !           328:        else {
        !           329:                if (blkdone >= 0) {
        !           330:                        sn += blkdone;
        !           331:                        (*pr)("%d of ", sn);
        !           332:                }
        !           333:                (*pr)("%d-%d", bp->b_blkno,
        !           334:                    bp->b_blkno + (bp->b_bcount - 1) / DEV_BSIZE);
        !           335:        }
        !           336:        if (lp && (blkdone >= 0 || bp->b_bcount <= lp->d_secsize)) {
        !           337: #ifdef tahoe
        !           338:                sn *= DEV_BSIZE / lp->d_secsize;                /* XXX */
        !           339: #endif
        !           340:                sn += lp->d_partitions[part].p_offset;
        !           341:                (*pr)(" (%s%d bn %d; cn %d", dname, unit, sn,
        !           342:                    sn / lp->d_secpercyl);
        !           343:                sn %= lp->d_secpercyl;
        !           344:                (*pr)(" tn %d sn %d)", sn / lp->d_nsectors, sn % lp->d_nsectors);
        !           345:        }
        !           346: }

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