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

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    1 /*-
    2  * Copyright (c) 2002 Poul-Henning Kamp
    3  * Copyright (c) 2002 Networks Associates Technology, Inc.
    4  * All rights reserved.
    5  *
    6  * This software was developed for the FreeBSD Project by Poul-Henning Kamp
    7  * and NAI Labs, the Security Research Division of Network Associates, Inc.
    8  * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
    9  * DARPA CHATS research program.
   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  * 3. The names of the authors may not be used to endorse or promote
   20  *    products derived from this software without specific prior written
   21  *    permission.
   22  *
   23  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   33  * SUCH DAMAGE.
   34  */
   35 
   36 #include <sys/cdefs.h>
   37 __FBSDID("$FreeBSD: releng/9.1/sys/geom/geom_dev.c 223089 2011-06-14 17:10:32Z gibbs $");
   38 
   39 #include <sys/param.h>
   40 #include <sys/systm.h>
   41 #include <sys/malloc.h>
   42 #include <sys/kernel.h>
   43 #include <sys/conf.h>
   44 #include <sys/ctype.h>
   45 #include <sys/bio.h>
   46 #include <sys/lock.h>
   47 #include <sys/mutex.h>
   48 #include <sys/proc.h>
   49 #include <sys/errno.h>
   50 #include <sys/time.h>
   51 #include <sys/disk.h>
   52 #include <sys/fcntl.h>
   53 #include <sys/limits.h>
   54 #include <geom/geom.h>
   55 #include <geom/geom_int.h>
   56 #include <machine/stdarg.h>
   57 
   58 /*
   59  * Use the consumer private field to reference a physdev alias (if any).
   60  */
   61 #define cp_alias_dev    private
   62 
   63 static d_open_t         g_dev_open;
   64 static d_close_t        g_dev_close;
   65 static d_strategy_t     g_dev_strategy;
   66 static d_ioctl_t        g_dev_ioctl;
   67 
   68 static struct cdevsw g_dev_cdevsw = {
   69         .d_version =    D_VERSION,
   70         .d_open =       g_dev_open,
   71         .d_close =      g_dev_close,
   72         .d_read =       physread,
   73         .d_write =      physwrite,
   74         .d_ioctl =      g_dev_ioctl,
   75         .d_strategy =   g_dev_strategy,
   76         .d_name =       "g_dev",
   77         .d_flags =      D_DISK | D_TRACKCLOSE,
   78 };
   79 
   80 static g_taste_t g_dev_taste;
   81 static g_orphan_t g_dev_orphan;
   82 static g_attrchanged_t g_dev_attrchanged;
   83 
   84 static struct g_class g_dev_class       = {
   85         .name = "DEV",
   86         .version = G_VERSION,
   87         .taste = g_dev_taste,
   88         .orphan = g_dev_orphan,
   89         .attrchanged = g_dev_attrchanged
   90 };
   91 
   92 void
   93 g_dev_print(void)
   94 {
   95         struct g_geom *gp;
   96         char const *p = "";
   97 
   98         LIST_FOREACH(gp, &g_dev_class.geom, geom) {
   99                 printf("%s%s", p, gp->name);
  100                 p = " ";
  101         }
  102         printf("\n");
  103 }
  104 
  105 static void
  106 g_dev_attrchanged(struct g_consumer *cp, const char *attr)
  107 {
  108 
  109         if (strcmp(attr, "GEOM::physpath") != 0)
  110                 return;
  111 
  112         if (g_access(cp, 1, 0, 0) == 0) {
  113                 char *physpath;
  114                 int error, physpath_len;
  115 
  116                 physpath_len = MAXPATHLEN;
  117                 physpath = g_malloc(physpath_len, M_WAITOK|M_ZERO);
  118                 error =
  119                     g_io_getattr("GEOM::physpath", cp, &physpath_len, physpath);
  120                 g_access(cp, -1, 0, 0);
  121                 if (error == 0 && strlen(physpath) != 0) {
  122                         struct cdev *dev;
  123                         struct cdev *old_alias_dev;
  124                         struct cdev **alias_devp;
  125 
  126                         dev = cp->geom->softc;
  127                         old_alias_dev = cp->cp_alias_dev;
  128                         alias_devp = (struct cdev **)&cp->cp_alias_dev;
  129                         make_dev_physpath_alias(MAKEDEV_WAITOK, alias_devp,
  130                             dev, old_alias_dev, physpath);
  131                 } else if (cp->cp_alias_dev) {
  132                         destroy_dev((struct cdev *)cp->cp_alias_dev);
  133                         cp->cp_alias_dev = NULL;
  134                 }
  135                 g_free(physpath);
  136         }
  137 }
  138 
  139 struct g_provider *
  140 g_dev_getprovider(struct cdev *dev)
  141 {
  142         struct g_consumer *cp;
  143 
  144         g_topology_assert();
  145         if (dev == NULL)
  146                 return (NULL);
  147         if (dev->si_devsw != &g_dev_cdevsw)
  148                 return (NULL);
  149         cp = dev->si_drv2;
  150         return (cp->provider);
  151 }
  152 
  153 static struct g_geom *
  154 g_dev_taste(struct g_class *mp, struct g_provider *pp, int insist __unused)
  155 {
  156         struct g_geom *gp;
  157         struct g_consumer *cp;
  158         int error, len;
  159         struct cdev *dev, *adev;
  160         char buf[64], *val;
  161 
  162         g_trace(G_T_TOPOLOGY, "dev_taste(%s,%s)", mp->name, pp->name);
  163         g_topology_assert();
  164         LIST_FOREACH(cp, &pp->consumers, consumers)
  165                 if (cp->geom->class == mp)
  166                         return (NULL);
  167         gp = g_new_geomf(mp, pp->name);
  168         cp = g_new_consumer(gp);
  169         error = g_attach(cp, pp);
  170         KASSERT(error == 0,
  171             ("g_dev_taste(%s) failed to g_attach, err=%d", pp->name, error));
  172         error = make_dev_p(MAKEDEV_CHECKNAME | MAKEDEV_WAITOK, &dev,
  173             &g_dev_cdevsw, NULL, UID_ROOT, GID_OPERATOR, 0640, "%s", gp->name);
  174         if (error != 0) {
  175                 printf("%s: make_dev_p() failed (gp->name=%s, error=%d)\n",
  176                     __func__, gp->name, error);
  177                 g_detach(cp);
  178                 g_destroy_consumer(cp);
  179                 g_destroy_geom(gp);
  180                 return (NULL);
  181         }
  182 
  183         /* Search for device alias name and create it if found. */
  184         adev = NULL;
  185         for (len = MIN(strlen(gp->name), sizeof(buf) - 15); len > 0; len--) {
  186                 snprintf(buf, sizeof(buf), "kern.devalias.%s", gp->name);
  187                 buf[14 + len] = 0;
  188                 val = getenv(buf);
  189                 if (val != NULL) {
  190                         snprintf(buf, sizeof(buf), "%s%s",
  191                             val, gp->name + len);
  192                         freeenv(val);
  193                         make_dev_alias_p(MAKEDEV_CHECKNAME | MAKEDEV_WAITOK,
  194                             &adev, dev, "%s", buf);
  195                         break;
  196                 }
  197         }
  198 
  199         if (pp->flags & G_PF_CANDELETE)
  200                 dev->si_flags |= SI_CANDELETE;
  201         dev->si_iosize_max = MAXPHYS;
  202         gp->softc = dev;
  203         dev->si_drv1 = gp;
  204         dev->si_drv2 = cp;
  205         if (adev != NULL) {
  206                 if (pp->flags & G_PF_CANDELETE)
  207                         adev->si_flags |= SI_CANDELETE;
  208                 adev->si_iosize_max = MAXPHYS;
  209                 adev->si_drv1 = gp;
  210                 adev->si_drv2 = cp;
  211         }
  212 
  213         g_dev_attrchanged(cp, "GEOM::physpath");
  214 
  215         return (gp);
  216 }
  217 
  218 static int
  219 g_dev_open(struct cdev *dev, int flags, int fmt, struct thread *td)
  220 {
  221         struct g_geom *gp;
  222         struct g_consumer *cp;
  223         int error, r, w, e;
  224 
  225         gp = dev->si_drv1;
  226         cp = dev->si_drv2;
  227         if (gp == NULL || cp == NULL || gp->softc != dev)
  228                 return(ENXIO);          /* g_dev_taste() not done yet */
  229 
  230         g_trace(G_T_ACCESS, "g_dev_open(%s, %d, %d, %p)",
  231             gp->name, flags, fmt, td);
  232 
  233         r = flags & FREAD ? 1 : 0;
  234         w = flags & FWRITE ? 1 : 0;
  235 #ifdef notyet
  236         e = flags & O_EXCL ? 1 : 0;
  237 #else
  238         e = 0;
  239 #endif
  240         if (w) {
  241                 /*
  242                  * When running in very secure mode, do not allow
  243                  * opens for writing of any disks.
  244                  */
  245                 error = securelevel_ge(td->td_ucred, 2);
  246                 if (error)
  247                         return (error);
  248         }
  249         g_topology_lock();
  250         if (dev->si_devsw == NULL)
  251                 error = ENXIO;          /* We were orphaned */
  252         else
  253                 error = g_access(cp, r, w, e);
  254         g_topology_unlock();
  255         return(error);
  256 }
  257 
  258 static int
  259 g_dev_close(struct cdev *dev, int flags, int fmt, struct thread *td)
  260 {
  261         struct g_geom *gp;
  262         struct g_consumer *cp;
  263         int error, r, w, e, i;
  264 
  265         gp = dev->si_drv1;
  266         cp = dev->si_drv2;
  267         if (gp == NULL || cp == NULL)
  268                 return(ENXIO);
  269         g_trace(G_T_ACCESS, "g_dev_close(%s, %d, %d, %p)",
  270             gp->name, flags, fmt, td);
  271         r = flags & FREAD ? -1 : 0;
  272         w = flags & FWRITE ? -1 : 0;
  273 #ifdef notyet
  274         e = flags & O_EXCL ? -1 : 0;
  275 #else
  276         e = 0;
  277 #endif
  278         g_topology_lock();
  279         if (dev->si_devsw == NULL)
  280                 error = ENXIO;          /* We were orphaned */
  281         else
  282                 error = g_access(cp, r, w, e);
  283         for (i = 0; i < 10 * hz;) {
  284                 if (cp->acr != 0 || cp->acw != 0)
  285                         break;
  286                 if (cp->nstart == cp->nend)
  287                         break;
  288                 pause("gdevwclose", hz / 10);
  289                 i += hz / 10;
  290         }
  291         if (cp->acr == 0 && cp->acw == 0 && cp->nstart != cp->nend) {
  292                 printf("WARNING: Final close of geom_dev(%s) %s %s\n",
  293                     gp->name,
  294                     "still has outstanding I/O after 10 seconds.",
  295                     "Completing close anyway, panic may happen later.");
  296         }
  297         g_topology_unlock();
  298         return (error);
  299 }
  300 
  301 /*
  302  * XXX: Until we have unmessed the ioctl situation, there is a race against
  303  * XXX: a concurrent orphanization.  We cannot close it by holding topology
  304  * XXX: since that would prevent us from doing our job, and stalling events
  305  * XXX: will break (actually: stall) the BSD disklabel hacks.
  306  */
  307 static int
  308 g_dev_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag, struct thread *td)
  309 {
  310         struct g_geom *gp;
  311         struct g_consumer *cp;
  312         struct g_provider *pp;
  313         struct g_kerneldump kd;
  314         off_t offset, length, chunk;
  315         int i, error;
  316         u_int u;
  317 
  318         gp = dev->si_drv1;
  319         cp = dev->si_drv2;
  320         pp = cp->provider;
  321 
  322         error = 0;
  323         KASSERT(cp->acr || cp->acw,
  324             ("Consumer with zero access count in g_dev_ioctl"));
  325 
  326         i = IOCPARM_LEN(cmd);
  327         switch (cmd) {
  328         case DIOCGSECTORSIZE:
  329                 *(u_int *)data = cp->provider->sectorsize;
  330                 if (*(u_int *)data == 0)
  331                         error = ENOENT;
  332                 break;
  333         case DIOCGMEDIASIZE:
  334                 *(off_t *)data = cp->provider->mediasize;
  335                 if (*(off_t *)data == 0)
  336                         error = ENOENT;
  337                 break;
  338         case DIOCGFWSECTORS:
  339                 error = g_io_getattr("GEOM::fwsectors", cp, &i, data);
  340                 if (error == 0 && *(u_int *)data == 0)
  341                         error = ENOENT;
  342                 break;
  343         case DIOCGFWHEADS:
  344                 error = g_io_getattr("GEOM::fwheads", cp, &i, data);
  345                 if (error == 0 && *(u_int *)data == 0)
  346                         error = ENOENT;
  347                 break;
  348         case DIOCGFRONTSTUFF:
  349                 error = g_io_getattr("GEOM::frontstuff", cp, &i, data);
  350                 break;
  351         case DIOCSKERNELDUMP:
  352                 u = *((u_int *)data);
  353                 if (!u) {
  354                         set_dumper(NULL);
  355                         error = 0;
  356                         break;
  357                 }
  358                 kd.offset = 0;
  359                 kd.length = OFF_MAX;
  360                 i = sizeof kd;
  361                 error = g_io_getattr("GEOM::kerneldump", cp, &i, &kd);
  362                 if (!error) {
  363                         error = set_dumper(&kd.di);
  364                         if (!error)
  365                                 dev->si_flags |= SI_DUMPDEV;
  366                 }
  367                 break;
  368         case DIOCGFLUSH:
  369                 error = g_io_flush(cp);
  370                 break;
  371         case DIOCGDELETE:
  372                 offset = ((off_t *)data)[0];
  373                 length = ((off_t *)data)[1];
  374                 if ((offset % cp->provider->sectorsize) != 0 ||
  375                     (length % cp->provider->sectorsize) != 0 || length <= 0) {
  376                         printf("%s: offset=%jd length=%jd\n", __func__, offset,
  377                             length);
  378                         error = EINVAL;
  379                         break;
  380                 }
  381                 while (length > 0) { 
  382                         chunk = length;
  383                         if (chunk > 65536 * cp->provider->sectorsize)
  384                                 chunk = 65536 * cp->provider->sectorsize;
  385                         error = g_delete_data(cp, offset, chunk);
  386                         length -= chunk;
  387                         offset += chunk;
  388                         if (error)
  389                                 break;
  390                         /*
  391                          * Since the request size is unbounded, the service
  392                          * time is likewise.  We make this ioctl interruptible
  393                          * by checking for signals for each bio.
  394                          */
  395                         if (SIGPENDING(td))
  396                                 break;
  397                 }
  398                 break;
  399         case DIOCGIDENT:
  400                 error = g_io_getattr("GEOM::ident", cp, &i, data);
  401                 break;
  402         case DIOCGPROVIDERNAME:
  403                 if (pp == NULL)
  404                         return (ENOENT);
  405                 strlcpy(data, pp->name, i);
  406                 break;
  407         case DIOCGSTRIPESIZE:
  408                 *(off_t *)data = cp->provider->stripesize;
  409                 break;
  410         case DIOCGSTRIPEOFFSET:
  411                 *(off_t *)data = cp->provider->stripeoffset;
  412                 break;
  413         case DIOCGPHYSPATH:
  414                 error = g_io_getattr("GEOM::physpath", cp, &i, data);
  415                 if (error == 0 && *(char *)data == '\0')
  416                         error = ENOENT;
  417                 break;
  418         default:
  419                 if (cp->provider->geom->ioctl != NULL) {
  420                         error = cp->provider->geom->ioctl(cp->provider, cmd, data, fflag, td);
  421                 } else {
  422                         error = ENOIOCTL;
  423                 }
  424         }
  425 
  426         return (error);
  427 }
  428 
  429 static void
  430 g_dev_done(struct bio *bp2)
  431 {
  432         struct bio *bp;
  433 
  434         bp = bp2->bio_parent;
  435         bp->bio_error = bp2->bio_error;
  436         if (bp->bio_error != 0) {
  437                 g_trace(G_T_BIO, "g_dev_done(%p) had error %d",
  438                     bp2, bp->bio_error);
  439                 bp->bio_flags |= BIO_ERROR;
  440         } else {
  441                 g_trace(G_T_BIO, "g_dev_done(%p/%p) resid %ld completed %jd",
  442                     bp2, bp, bp->bio_resid, (intmax_t)bp2->bio_completed);
  443         }
  444         bp->bio_resid = bp->bio_length - bp2->bio_completed;
  445         bp->bio_completed = bp2->bio_completed;
  446         g_destroy_bio(bp2);
  447         biodone(bp);
  448 }
  449 
  450 static void
  451 g_dev_strategy(struct bio *bp)
  452 {
  453         struct g_consumer *cp;
  454         struct bio *bp2;
  455         struct cdev *dev;
  456 
  457         KASSERT(bp->bio_cmd == BIO_READ ||
  458                 bp->bio_cmd == BIO_WRITE ||
  459                 bp->bio_cmd == BIO_DELETE,
  460                 ("Wrong bio_cmd bio=%p cmd=%d", bp, bp->bio_cmd));
  461         dev = bp->bio_dev;
  462         cp = dev->si_drv2;
  463         KASSERT(cp->acr || cp->acw,
  464             ("Consumer with zero access count in g_dev_strategy"));
  465 #ifdef INVARIANTS
  466         if ((bp->bio_offset % cp->provider->sectorsize) != 0 ||
  467             (bp->bio_bcount % cp->provider->sectorsize) != 0) {
  468                 bp->bio_resid = bp->bio_bcount;
  469                 biofinish(bp, NULL, EINVAL);
  470                 return;
  471         }
  472 #endif
  473         for (;;) {
  474                 /*
  475                  * XXX: This is not an ideal solution, but I belive it to
  476                  * XXX: deadlock safe, all things considered.
  477                  */
  478                 bp2 = g_clone_bio(bp);
  479                 if (bp2 != NULL)
  480                         break;
  481                 pause("gdstrat", hz / 10);
  482         }
  483         KASSERT(bp2 != NULL, ("XXX: ENOMEM in a bad place"));
  484         bp2->bio_done = g_dev_done;
  485         g_trace(G_T_BIO,
  486             "g_dev_strategy(%p/%p) offset %jd length %jd data %p cmd %d",
  487             bp, bp2, (intmax_t)bp->bio_offset, (intmax_t)bp2->bio_length,
  488             bp2->bio_data, bp2->bio_cmd);
  489         g_io_request(bp2, cp);
  490         KASSERT(cp->acr || cp->acw,
  491             ("g_dev_strategy raced with g_dev_close and lost"));
  492 
  493 }
  494 
  495 /*
  496  * g_dev_orphan()
  497  *
  498  * Called from below when the provider orphaned us.
  499  * - Clear any dump settings.
  500  * - Destroy the struct cdev *to prevent any more request from coming in.  The
  501  *   provider is already marked with an error, so anything which comes in
  502  *   in the interrim will be returned immediately.
  503  * - Wait for any outstanding I/O to finish.
  504  * - Set our access counts to zero, whatever they were.
  505  * - Detach and self-destruct.
  506  */
  507 
  508 static void
  509 g_dev_orphan(struct g_consumer *cp)
  510 {
  511         struct g_geom *gp;
  512         struct cdev *dev;
  513 
  514         g_topology_assert();
  515         gp = cp->geom;
  516         dev = gp->softc;
  517         g_trace(G_T_TOPOLOGY, "g_dev_orphan(%p(%s))", cp, gp->name);
  518 
  519         /* Reset any dump-area set on this device */
  520         if (dev->si_flags & SI_DUMPDEV)
  521                 set_dumper(NULL);
  522 
  523         /* Destroy the struct cdev *so we get no more requests */
  524         destroy_dev(dev);
  525 
  526         /* Wait for the cows to come home */
  527         while (cp->nstart != cp->nend)
  528                 pause("gdevorphan", hz / 10);
  529 
  530         if (cp->acr > 0 || cp->acw > 0 || cp->ace > 0)
  531                 g_access(cp, -cp->acr, -cp->acw, -cp->ace);
  532 
  533         g_detach(cp);
  534         g_destroy_consumer(cp);
  535         g_destroy_geom(gp);
  536 }
  537 
  538 DECLARE_GEOM_CLASS(g_dev_class, g_dev);

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