The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_disk.c

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    1 /*      $NetBSD: subr_disk.c,v 1.100 2010/10/14 00:47:16 mrg Exp $      */
    2 
    3 /*-
    4  * Copyright (c) 1996, 1997, 1999, 2000, 2009 The NetBSD Foundation, Inc.
    5  * All rights reserved.
    6  *
    7  * This code is derived from software contributed to The NetBSD Foundation
    8  * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
    9  * NASA Ames Research Center.
   10  *
   11  * Redistribution and use in source and binary forms, with or without
   12  * modification, are permitted provided that the following conditions
   13  * are met:
   14  * 1. Redistributions of source code must retain the above copyright
   15  *    notice, this list of conditions and the following disclaimer.
   16  * 2. Redistributions in binary form must reproduce the above copyright
   17  *    notice, this list of conditions and the following disclaimer in the
   18  *    documentation and/or other materials provided with the distribution.
   19  *
   20  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
   21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
   22  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   23  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
   24  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   25  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   26  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   27  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   28  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   29  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   30  * POSSIBILITY OF SUCH DAMAGE.
   31  */
   32 
   33 /*
   34  * Copyright (c) 1982, 1986, 1988, 1993
   35  *      The Regents of the University of California.  All rights reserved.
   36  * (c) UNIX System Laboratories, Inc.
   37  * All or some portions of this file are derived from material licensed
   38  * to the University of California by American Telephone and Telegraph
   39  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
   40  * the permission of UNIX System Laboratories, Inc.
   41  *
   42  * Redistribution and use in source and binary forms, with or without
   43  * modification, are permitted provided that the following conditions
   44  * are met:
   45  * 1. Redistributions of source code must retain the above copyright
   46  *    notice, this list of conditions and the following disclaimer.
   47  * 2. Redistributions in binary form must reproduce the above copyright
   48  *    notice, this list of conditions and the following disclaimer in the
   49  *    documentation and/or other materials provided with the distribution.
   50  * 3. Neither the name of the University nor the names of its contributors
   51  *    may be used to endorse or promote products derived from this software
   52  *    without specific prior written permission.
   53  *
   54  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   55  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   56  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   57  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   58  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   59  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   60  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   61  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   62  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   63  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   64  * SUCH DAMAGE.
   65  *
   66  *      @(#)ufs_disksubr.c      8.5 (Berkeley) 1/21/94
   67  */
   68 
   69 #include <sys/cdefs.h>
   70 __KERNEL_RCSID(0, "$NetBSD: subr_disk.c,v 1.100 2010/10/14 00:47:16 mrg Exp $");
   71 
   72 #include <sys/param.h>
   73 #include <sys/kernel.h>
   74 #include <sys/kmem.h>
   75 #include <sys/buf.h>
   76 #include <sys/syslog.h>
   77 #include <sys/disklabel.h>
   78 #include <sys/disk.h>
   79 #include <sys/sysctl.h>
   80 #include <lib/libkern/libkern.h>
   81 
   82 /*
   83  * Compute checksum for disk label.
   84  */
   85 u_int
   86 dkcksum(struct disklabel *lp)
   87 {
   88 
   89         return dkcksum_sized(lp, lp->d_npartitions);
   90 }
   91 
   92 u_int
   93 dkcksum_sized(struct disklabel *lp, size_t npartitions)
   94 {
   95         uint16_t *start, *end;
   96         uint16_t sum = 0;
   97 
   98         start = (uint16_t *)lp;
   99         end = (uint16_t *)&lp->d_partitions[npartitions];
  100         while (start < end)
  101                 sum ^= *start++;
  102         return sum;
  103 }
  104 
  105 /*
  106  * Disk error is the preface to plaintive error messages
  107  * about failing disk transfers.  It prints messages of the form
  108 
  109 hp0g: hard error reading fsbn 12345 of 12344-12347 (hp0 bn %d cn %d tn %d sn %d)
  110 
  111  * if the offset of the error in the transfer and a disk label
  112  * are both available.  blkdone should be -1 if the position of the error
  113  * is unknown; the disklabel pointer may be null from drivers that have not
  114  * been converted to use them.  The message is printed with printf
  115  * if pri is LOG_PRINTF, otherwise it uses log at the specified priority.
  116  * The message should be completed (with at least a newline) with printf
  117  * or addlog, respectively.  There is no trailing space.
  118  */
  119 #ifndef PRIdaddr
  120 #define PRIdaddr PRId64
  121 #endif
  122 void
  123 diskerr(const struct buf *bp, const char *dname, const char *what, int pri,
  124     int blkdone, const struct disklabel *lp)
  125 {
  126         int unit = DISKUNIT(bp->b_dev), part = DISKPART(bp->b_dev);
  127         void (*pr)(const char *, ...);
  128         char partname = 'a' + part;
  129         daddr_t sn;
  130 
  131         if (/*CONSTCOND*/0)
  132                 /* Compiler will error this is the format is wrong... */
  133                 printf("%" PRIdaddr, bp->b_blkno);
  134 
  135         if (pri != LOG_PRINTF) {
  136                 static const char fmt[] = "";
  137                 log(pri, fmt);
  138                 pr = addlog;
  139         } else
  140                 pr = printf;
  141         (*pr)("%s%d%c: %s %sing fsbn ", dname, unit, partname, what,
  142             bp->b_flags & B_READ ? "read" : "writ");
  143         sn = bp->b_blkno;
  144         if (bp->b_bcount <= DEV_BSIZE)
  145                 (*pr)("%" PRIdaddr, sn);
  146         else {
  147                 if (blkdone >= 0) {
  148                         sn += blkdone;
  149                         (*pr)("%" PRIdaddr " of ", sn);
  150                 }
  151                 (*pr)("%" PRIdaddr "-%" PRIdaddr "", bp->b_blkno,
  152                     bp->b_blkno + (bp->b_bcount - 1) / DEV_BSIZE);
  153         }
  154         if (lp && (blkdone >= 0 || bp->b_bcount <= lp->d_secsize)) {
  155                 sn += lp->d_partitions[part].p_offset;
  156                 (*pr)(" (%s%d bn %" PRIdaddr "; cn %" PRIdaddr "",
  157                     dname, unit, sn, sn / lp->d_secpercyl);
  158                 sn %= lp->d_secpercyl;
  159                 (*pr)(" tn %" PRIdaddr " sn %" PRIdaddr ")",
  160                     sn / lp->d_nsectors, sn % lp->d_nsectors);
  161         }
  162 }
  163 
  164 /*
  165  * Searches the iostatlist for the disk corresponding to the
  166  * name provided.
  167  */
  168 struct disk *
  169 disk_find(const char *name)
  170 {
  171         struct io_stats *stat;
  172 
  173         stat = iostat_find(name);
  174 
  175         if ((stat != NULL) && (stat->io_type == IOSTAT_DISK))
  176                 return stat->io_parent;
  177 
  178         return (NULL);
  179 }
  180 
  181 void
  182 disk_init(struct disk *diskp, const char *name, const struct dkdriver *driver)
  183 {
  184 
  185         /*
  186          * Initialize the wedge-related locks and other fields.
  187          */
  188         mutex_init(&diskp->dk_rawlock, MUTEX_DEFAULT, IPL_NONE);
  189         mutex_init(&diskp->dk_openlock, MUTEX_DEFAULT, IPL_NONE);
  190         LIST_INIT(&diskp->dk_wedges);
  191         diskp->dk_nwedges = 0;
  192         diskp->dk_labelsector = LABELSECTOR;
  193         disk_blocksize(diskp, DEV_BSIZE);
  194         diskp->dk_name = name;
  195         diskp->dk_driver = driver;
  196 }
  197 
  198 /*
  199  * Attach a disk.
  200  */
  201 void
  202 disk_attach(struct disk *diskp)
  203 {
  204 
  205         /*
  206          * Allocate and initialize the disklabel structures.
  207          */
  208         diskp->dk_label = kmem_zalloc(sizeof(struct disklabel), KM_SLEEP);
  209         diskp->dk_cpulabel = kmem_zalloc(sizeof(struct cpu_disklabel),
  210             KM_SLEEP);
  211         if ((diskp->dk_label == NULL) || (diskp->dk_cpulabel == NULL))
  212                 panic("disk_attach: can't allocate storage for disklabel");
  213 
  214         /*
  215          * Set up the stats collection.
  216          */
  217         diskp->dk_stats = iostat_alloc(IOSTAT_DISK, diskp, diskp->dk_name);
  218 }
  219 
  220 int
  221 disk_begindetach(struct disk *dk, int (*lastclose)(device_t),
  222     device_t self, int flags)
  223 {
  224         int rc;
  225 
  226         rc = 0;
  227         mutex_enter(&dk->dk_openlock);
  228         if (dk->dk_openmask == 0)
  229                 ;       /* nothing to do */
  230         else if ((flags & DETACH_FORCE) == 0)
  231                 rc = EBUSY;
  232         else if (lastclose != NULL)
  233                 rc = (*lastclose)(self);
  234         mutex_exit(&dk->dk_openlock);
  235 
  236         return rc;
  237 }
  238 
  239 /*
  240  * Detach a disk.
  241  */
  242 void
  243 disk_detach(struct disk *diskp)
  244 {
  245 
  246         /*
  247          * Remove from the drivelist.
  248          */
  249         iostat_free(diskp->dk_stats);
  250 
  251         /*
  252          * Release the disk-info dictionary.
  253          */
  254         if (diskp->dk_info) {
  255                 prop_object_release(diskp->dk_info);
  256                 diskp->dk_info = NULL;
  257         }
  258 
  259         /*
  260          * Free the space used by the disklabel structures.
  261          */
  262         kmem_free(diskp->dk_label, sizeof(*diskp->dk_label));
  263         kmem_free(diskp->dk_cpulabel, sizeof(*diskp->dk_cpulabel));
  264 }
  265 
  266 void
  267 disk_destroy(struct disk *diskp)
  268 {
  269 
  270         mutex_destroy(&diskp->dk_openlock);
  271         mutex_destroy(&diskp->dk_rawlock);
  272 }
  273 
  274 /*
  275  * Mark the disk as busy for metrics collection.
  276  */
  277 void
  278 disk_busy(struct disk *diskp)
  279 {
  280 
  281         iostat_busy(diskp->dk_stats);
  282 }
  283 
  284 /*
  285  * Finished disk operations, gather metrics.
  286  */
  287 void
  288 disk_unbusy(struct disk *diskp, long bcount, int read)
  289 {
  290 
  291         iostat_unbusy(diskp->dk_stats, bcount, read);
  292 }
  293 
  294 /*
  295  * Return true if disk has an I/O operation in flight.
  296  */
  297 bool
  298 disk_isbusy(struct disk *diskp)
  299 {
  300 
  301         return iostat_isbusy(diskp->dk_stats);
  302 }
  303 
  304 /*
  305  * Set the physical blocksize of a disk, in bytes.
  306  * Only necessary if blocksize != DEV_BSIZE.
  307  */
  308 void
  309 disk_blocksize(struct disk *diskp, int blocksize)
  310 {
  311 
  312         diskp->dk_blkshift = DK_BSIZE2BLKSHIFT(blocksize);
  313         diskp->dk_byteshift = DK_BSIZE2BYTESHIFT(blocksize);
  314 }
  315 
  316 /*
  317  * Bounds checking against the media size, used for the raw partition.
  318  * secsize, mediasize and b_blkno must all be the same units.
  319  * Possibly this has to be DEV_BSIZE (512).
  320  */
  321 int
  322 bounds_check_with_mediasize(struct buf *bp, int secsize, uint64_t mediasize)
  323 {
  324         int64_t sz;
  325 
  326         sz = howmany(bp->b_bcount, secsize);
  327 
  328         if (bp->b_blkno + sz > mediasize) {
  329                 sz = mediasize - bp->b_blkno;
  330                 if (sz == 0) {
  331                         /* If exactly at end of disk, return EOF. */
  332                         bp->b_resid = bp->b_bcount;
  333                         return 0;
  334                 }
  335                 if (sz < 0) {
  336                         /* If past end of disk, return EINVAL. */
  337                         bp->b_error = EINVAL;
  338                         return 0;
  339                 }
  340                 /* Otherwise, truncate request. */
  341                 bp->b_bcount = sz * secsize;
  342         }
  343 
  344         return 1;
  345 }
  346 
  347 /*
  348  * Determine the size of the transfer, and make sure it is
  349  * within the boundaries of the partition. Adjust transfer
  350  * if needed, and signal errors or early completion.
  351  */
  352 int
  353 bounds_check_with_label(struct disk *dk, struct buf *bp, int wlabel)
  354 {
  355         struct disklabel *lp = dk->dk_label;
  356         struct partition *p = lp->d_partitions + DISKPART(bp->b_dev);
  357         uint64_t p_size, p_offset, labelsector;
  358         int64_t sz;
  359 
  360         /* Protect against division by zero. XXX: Should never happen?!?! */
  361         if (lp->d_secpercyl == 0) {
  362                 bp->b_error = EINVAL;
  363                 return -1;
  364         }
  365 
  366         p_size = (uint64_t)p->p_size << dk->dk_blkshift;
  367         p_offset = (uint64_t)p->p_offset << dk->dk_blkshift;
  368 #if RAW_PART == 3
  369         labelsector = lp->d_partitions[2].p_offset;
  370 #else
  371         labelsector = lp->d_partitions[RAW_PART].p_offset;
  372 #endif
  373         labelsector = (labelsector + dk->dk_labelsector) << dk->dk_blkshift;
  374 
  375         sz = howmany(bp->b_bcount, DEV_BSIZE);
  376         if ((bp->b_blkno + sz) > p_size) {
  377                 sz = p_size - bp->b_blkno;
  378                 if (sz == 0) {
  379                         /* If exactly at end of disk, return EOF. */
  380                         bp->b_resid = bp->b_bcount;
  381                         return 0;
  382                 }
  383                 if (sz < 0) {
  384                         /* If past end of disk, return EINVAL. */
  385                         bp->b_error = EINVAL;
  386                         return -1;
  387                 }
  388                 /* Otherwise, truncate request. */
  389                 bp->b_bcount = sz << DEV_BSHIFT;
  390         }
  391 
  392         /* Overwriting disk label? */
  393         if (bp->b_blkno + p_offset <= labelsector &&
  394             bp->b_blkno + p_offset + sz > labelsector &&
  395             (bp->b_flags & B_READ) == 0 && !wlabel) {
  396                 bp->b_error = EROFS;
  397                 return -1;
  398         }
  399 
  400         /* calculate cylinder for disksort to order transfers with */
  401         bp->b_cylinder = (bp->b_blkno + p->p_offset) /
  402             (lp->d_secsize / DEV_BSIZE) / lp->d_secpercyl;
  403         return 1;
  404 }
  405 
  406 int
  407 disk_read_sectors(void (*strat)(struct buf *), const struct disklabel *lp,
  408     struct buf *bp, unsigned int sector, int count)
  409 {
  410         bp->b_blkno = sector;
  411         bp->b_bcount = count * lp->d_secsize;
  412         bp->b_flags = (bp->b_flags & ~B_WRITE) | B_READ;
  413         bp->b_oflags &= ~BO_DONE;
  414         bp->b_cylinder = sector / lp->d_secpercyl;
  415         (*strat)(bp);
  416         return biowait(bp);
  417 }
  418 
  419 const char *
  420 convertdisklabel(struct disklabel *lp, void (*strat)(struct buf *),
  421     struct buf *bp, uint32_t secperunit)
  422 {
  423         struct partition rp, *altp, *p;
  424         int geom_ok;
  425 
  426         memset(&rp, 0, sizeof(rp));
  427         rp.p_size = secperunit;
  428         rp.p_fstype = FS_UNUSED;
  429 
  430         /* If we can seek to d_secperunit - 1, believe the disk geometry. */
  431         if (secperunit != 0 &&
  432             disk_read_sectors(strat, lp, bp, secperunit - 1, 1) == 0)
  433                 geom_ok = 1;
  434         else
  435                 geom_ok = 0;
  436 
  437 #if 0
  438         printf("%s: secperunit (%" PRIu32 ") %s\n", __func__,
  439             secperunit, geom_ok ? "ok" : "not ok");
  440 #endif
  441 
  442         p = &lp->d_partitions[RAW_PART];
  443         if (RAW_PART == 'c' - 'a')
  444                 altp = &lp->d_partitions['d' - 'a'];
  445         else
  446                 altp = &lp->d_partitions['c' - 'a'];
  447 
  448         if (lp->d_npartitions > RAW_PART && p->p_offset == 0 && p->p_size != 0)
  449                 ;       /* already a raw partition */
  450         else if (lp->d_npartitions > MAX('c', 'd') - 'a' &&
  451                  altp->p_offset == 0 && altp->p_size != 0) {
  452                 /* alternate partition ('c' or 'd') is suitable for raw slot,
  453                  * swap with 'd' or 'c'.
  454                  */
  455                 rp = *p;
  456                 *p = *altp;
  457                 *altp = rp;
  458         } else if (lp->d_npartitions <= RAW_PART &&
  459                    lp->d_npartitions > 'c' - 'a') {
  460                 /* No raw partition is present, but the alternate is present.
  461                  * Copy alternate to raw partition.
  462                  */
  463                 lp->d_npartitions = RAW_PART + 1;
  464                 *p = *altp;
  465         } else if (!geom_ok)
  466                 return "no raw partition and disk reports bad geometry";
  467         else if (lp->d_npartitions <= RAW_PART) {
  468                 memset(&lp->d_partitions[lp->d_npartitions], 0,
  469                     sizeof(struct partition) * (RAW_PART - lp->d_npartitions));
  470                 *p = rp;
  471                 lp->d_npartitions = RAW_PART + 1;
  472         } else if (lp->d_npartitions < MAXPARTITIONS) {
  473                 memmove(p + 1, p,
  474                     sizeof(struct partition) * (lp->d_npartitions - RAW_PART));
  475                 *p = rp;
  476                 lp->d_npartitions++;
  477         } else
  478                 return "no raw partition and partition table is full";
  479         return NULL;
  480 }
  481 
  482 /*
  483  * disk_ioctl --
  484  *      Generic disk ioctl handling.
  485  */
  486 int
  487 disk_ioctl(struct disk *diskp, u_long cmd, void *data, int flag,
  488            struct lwp *l)
  489 {
  490         int error;
  491 
  492         switch (cmd) {
  493         case DIOCGDISKINFO:
  494             {
  495                 struct plistref *pref = (struct plistref *) data;
  496 
  497                 if (diskp->dk_info == NULL)
  498                         error = ENOTSUP;
  499                 else
  500                         error = prop_dictionary_copyout_ioctl(pref, cmd,
  501                                                         diskp->dk_info);
  502                 break;
  503             }
  504 
  505         default:
  506                 error = EPASSTHROUGH;
  507         }
  508 
  509         return (error);
  510 }

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