The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: 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/8.0/sys/geom/geom_dev.c 195436 2009-07-08 05:56:14Z marcel $");
   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/bio.h>
   45 #include <sys/lock.h>
   46 #include <sys/mutex.h>
   47 #include <sys/proc.h>
   48 #include <sys/errno.h>
   49 #include <sys/time.h>
   50 #include <sys/disk.h>
   51 #include <sys/fcntl.h>
   52 #include <sys/limits.h>
   53 #include <geom/geom.h>
   54 #include <geom/geom_int.h>
   55 
   56 static d_open_t         g_dev_open;
   57 static d_close_t        g_dev_close;
   58 static d_strategy_t     g_dev_strategy;
   59 static d_ioctl_t        g_dev_ioctl;
   60 
   61 static struct cdevsw g_dev_cdevsw = {
   62         .d_version =    D_VERSION,
   63         .d_open =       g_dev_open,
   64         .d_close =      g_dev_close,
   65         .d_read =       physread,
   66         .d_write =      physwrite,
   67         .d_ioctl =      g_dev_ioctl,
   68         .d_strategy =   g_dev_strategy,
   69         .d_name =       "g_dev",
   70         .d_flags =      D_DISK | D_TRACKCLOSE,
   71 };
   72 
   73 static g_taste_t g_dev_taste;
   74 static g_orphan_t g_dev_orphan;
   75 
   76 static struct g_class g_dev_class       = {
   77         .name = "DEV",
   78         .version = G_VERSION,
   79         .taste = g_dev_taste,
   80         .orphan = g_dev_orphan,
   81 };
   82 
   83 void
   84 g_dev_print(void)
   85 {
   86         struct g_geom *gp;
   87         char const *p = "";
   88 
   89         LIST_FOREACH(gp, &g_dev_class.geom, geom) {
   90                 printf("%s%s", p, gp->name);
   91                 p = " ";
   92         }
   93         printf("\n");
   94 }
   95 
   96 struct g_provider *
   97 g_dev_getprovider(struct cdev *dev)
   98 {
   99         struct g_consumer *cp;
  100 
  101         g_topology_assert();
  102         if (dev == NULL)
  103                 return (NULL);
  104         if (dev->si_devsw != &g_dev_cdevsw)
  105                 return (NULL);
  106         cp = dev->si_drv2;
  107         return (cp->provider);
  108 }
  109 
  110 
  111 static struct g_geom *
  112 g_dev_taste(struct g_class *mp, struct g_provider *pp, int insist __unused)
  113 {
  114         struct g_geom *gp;
  115         struct g_consumer *cp;
  116         int error;
  117         struct cdev *dev;
  118 
  119         g_trace(G_T_TOPOLOGY, "dev_taste(%s,%s)", mp->name, pp->name);
  120         g_topology_assert();
  121         LIST_FOREACH(cp, &pp->consumers, consumers)
  122                 if (cp->geom->class == mp)
  123                         return (NULL);
  124         gp = g_new_geomf(mp, pp->name);
  125         cp = g_new_consumer(gp);
  126         error = g_attach(cp, pp);
  127         KASSERT(error == 0,
  128             ("g_dev_taste(%s) failed to g_attach, err=%d", pp->name, error));
  129         dev = make_dev(&g_dev_cdevsw, 0,
  130             UID_ROOT, GID_OPERATOR, 0640, gp->name);
  131         if (pp->flags & G_PF_CANDELETE)
  132                 dev->si_flags |= SI_CANDELETE;
  133         dev->si_iosize_max = MAXPHYS;
  134         gp->softc = dev;
  135         dev->si_drv1 = gp;
  136         dev->si_drv2 = cp;
  137         return (gp);
  138 }
  139 
  140 static int
  141 g_dev_open(struct cdev *dev, int flags, int fmt, struct thread *td)
  142 {
  143         struct g_geom *gp;
  144         struct g_consumer *cp;
  145         int error, r, w, e;
  146 
  147         gp = dev->si_drv1;
  148         cp = dev->si_drv2;
  149         if (gp == NULL || cp == NULL || gp->softc != dev)
  150                 return(ENXIO);          /* g_dev_taste() not done yet */
  151 
  152         g_trace(G_T_ACCESS, "g_dev_open(%s, %d, %d, %p)",
  153             gp->name, flags, fmt, td);
  154 
  155         r = flags & FREAD ? 1 : 0;
  156         w = flags & FWRITE ? 1 : 0;
  157 #ifdef notyet
  158         e = flags & O_EXCL ? 1 : 0;
  159 #else
  160         e = 0;
  161 #endif
  162         if (w) {
  163                 /*
  164                  * When running in very secure mode, do not allow
  165                  * opens for writing of any disks.
  166                  */
  167                 error = securelevel_ge(td->td_ucred, 2);
  168                 if (error)
  169                         return (error);
  170         }
  171         g_topology_lock();
  172         if (dev->si_devsw == NULL)
  173                 error = ENXIO;          /* We were orphaned */
  174         else
  175                 error = g_access(cp, r, w, e);
  176         g_topology_unlock();
  177         return(error);
  178 }
  179 
  180 static int
  181 g_dev_close(struct cdev *dev, int flags, int fmt, struct thread *td)
  182 {
  183         struct g_geom *gp;
  184         struct g_consumer *cp;
  185         int error, r, w, e, i;
  186 
  187         gp = dev->si_drv1;
  188         cp = dev->si_drv2;
  189         if (gp == NULL || cp == NULL)
  190                 return(ENXIO);
  191         g_trace(G_T_ACCESS, "g_dev_close(%s, %d, %d, %p)",
  192             gp->name, flags, fmt, td);
  193         r = flags & FREAD ? -1 : 0;
  194         w = flags & FWRITE ? -1 : 0;
  195 #ifdef notyet
  196         e = flags & O_EXCL ? -1 : 0;
  197 #else
  198         e = 0;
  199 #endif
  200         g_topology_lock();
  201         if (dev->si_devsw == NULL)
  202                 error = ENXIO;          /* We were orphaned */
  203         else
  204                 error = g_access(cp, r, w, e);
  205         for (i = 0; i < 10 * hz;) {
  206                 if (cp->acr != 0 || cp->acw != 0)
  207                         break;
  208                 if (cp->nstart == cp->nend)
  209                         break;
  210                 pause("gdevwclose", hz / 10);
  211                 i += hz / 10;
  212         }
  213         if (cp->acr == 0 && cp->acw == 0 && cp->nstart != cp->nend) {
  214                 printf("WARNING: Final close of geom_dev(%s) %s %s\n",
  215                     gp->name,
  216                     "still has outstanding I/O after 10 seconds.",
  217                     "Completing close anyway, panic may happen later.");
  218         }
  219         g_topology_unlock();
  220         return (error);
  221 }
  222 
  223 /*
  224  * XXX: Until we have unmessed the ioctl situation, there is a race against
  225  * XXX: a concurrent orphanization.  We cannot close it by holding topology
  226  * XXX: since that would prevent us from doing our job, and stalling events
  227  * XXX: will break (actually: stall) the BSD disklabel hacks.
  228  */
  229 static int
  230 g_dev_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag, struct thread *td)
  231 {
  232         struct g_geom *gp;
  233         struct g_consumer *cp;
  234         struct g_provider *pp;
  235         struct g_kerneldump kd;
  236         off_t offset, length, chunk;
  237         int i, error;
  238         u_int u;
  239 
  240         gp = dev->si_drv1;
  241         cp = dev->si_drv2;
  242         pp = cp->provider;
  243 
  244         error = 0;
  245         KASSERT(cp->acr || cp->acw,
  246             ("Consumer with zero access count in g_dev_ioctl"));
  247 
  248         i = IOCPARM_LEN(cmd);
  249         switch (cmd) {
  250         case DIOCGSECTORSIZE:
  251                 *(u_int *)data = cp->provider->sectorsize;
  252                 if (*(u_int *)data == 0)
  253                         error = ENOENT;
  254                 break;
  255         case DIOCGMEDIASIZE:
  256                 *(off_t *)data = cp->provider->mediasize;
  257                 if (*(off_t *)data == 0)
  258                         error = ENOENT;
  259                 break;
  260         case DIOCGFWSECTORS:
  261                 error = g_io_getattr("GEOM::fwsectors", cp, &i, data);
  262                 if (error == 0 && *(u_int *)data == 0)
  263                         error = ENOENT;
  264                 break;
  265         case DIOCGFWHEADS:
  266                 error = g_io_getattr("GEOM::fwheads", cp, &i, data);
  267                 if (error == 0 && *(u_int *)data == 0)
  268                         error = ENOENT;
  269                 break;
  270         case DIOCGFRONTSTUFF:
  271                 error = g_io_getattr("GEOM::frontstuff", cp, &i, data);
  272                 break;
  273         case DIOCSKERNELDUMP:
  274                 u = *((u_int *)data);
  275                 if (!u) {
  276                         set_dumper(NULL);
  277                         error = 0;
  278                         break;
  279                 }
  280                 kd.offset = 0;
  281                 kd.length = OFF_MAX;
  282                 i = sizeof kd;
  283                 error = g_io_getattr("GEOM::kerneldump", cp, &i, &kd);
  284                 if (!error)
  285                         dev->si_flags |= SI_DUMPDEV;
  286                 break;
  287         case DIOCGFLUSH:
  288                 error = g_io_flush(cp);
  289                 break;
  290         case DIOCGDELETE:
  291                 offset = ((off_t *)data)[0];
  292                 length = ((off_t *)data)[1];
  293                 if ((offset % cp->provider->sectorsize) != 0 ||
  294                     (length % cp->provider->sectorsize) != 0 || length <= 0) {
  295                         printf("%s: offset=%jd length=%jd\n", __func__, offset,
  296                             length);
  297                         error = EINVAL;
  298                         break;
  299                 }
  300                 while (length > 0) { 
  301                         chunk = length;
  302                         if (chunk > 1024 * cp->provider->sectorsize)
  303                                 chunk = 1024 * cp->provider->sectorsize;
  304                         error = g_delete_data(cp, offset, chunk);
  305                         length -= chunk;
  306                         offset += chunk;
  307                         if (error)
  308                                 break;
  309                         /*
  310                          * Since the request size is unbounded, the service
  311                          * time is likewise.  We make this ioctl interruptible
  312                          * by checking for signals for each bio.
  313                          */
  314                         if (SIGPENDING(td))
  315                                 break;
  316                 }
  317                 break;
  318         case DIOCGIDENT:
  319                 error = g_io_getattr("GEOM::ident", cp, &i, data);
  320                 break;
  321         case DIOCGPROVIDERNAME:
  322                 if (pp == NULL)
  323                         return (ENOENT);
  324                 strlcpy(data, pp->name, i);
  325                 break;
  326 
  327         default:
  328                 if (cp->provider->geom->ioctl != NULL) {
  329                         error = cp->provider->geom->ioctl(cp->provider, cmd, data, fflag, td);
  330                 } else {
  331                         error = ENOIOCTL;
  332                 }
  333         }
  334 
  335         return (error);
  336 }
  337 
  338 static void
  339 g_dev_done(struct bio *bp2)
  340 {
  341         struct bio *bp;
  342 
  343         bp = bp2->bio_parent;
  344         bp->bio_error = bp2->bio_error;
  345         if (bp->bio_error != 0) {
  346                 g_trace(G_T_BIO, "g_dev_done(%p) had error %d",
  347                     bp2, bp->bio_error);
  348                 bp->bio_flags |= BIO_ERROR;
  349         } else {
  350                 g_trace(G_T_BIO, "g_dev_done(%p/%p) resid %ld completed %jd",
  351                     bp2, bp, bp->bio_resid, (intmax_t)bp2->bio_completed);
  352         }
  353         bp->bio_resid = bp->bio_length - bp2->bio_completed;
  354         bp->bio_completed = bp2->bio_completed;
  355         g_destroy_bio(bp2);
  356         biodone(bp);
  357 }
  358 
  359 static void
  360 g_dev_strategy(struct bio *bp)
  361 {
  362         struct g_consumer *cp;
  363         struct bio *bp2;
  364         struct cdev *dev;
  365 
  366         KASSERT(bp->bio_cmd == BIO_READ ||
  367                 bp->bio_cmd == BIO_WRITE ||
  368                 bp->bio_cmd == BIO_DELETE,
  369                 ("Wrong bio_cmd bio=%p cmd=%d", bp, bp->bio_cmd));
  370         dev = bp->bio_dev;
  371         cp = dev->si_drv2;
  372         KASSERT(cp->acr || cp->acw,
  373             ("Consumer with zero access count in g_dev_strategy"));
  374 
  375         if ((bp->bio_offset % cp->provider->sectorsize) != 0 ||
  376             (bp->bio_bcount % cp->provider->sectorsize) != 0) {
  377                 bp->bio_resid = bp->bio_bcount;
  378                 biofinish(bp, NULL, EINVAL);
  379                 return;
  380         }
  381 
  382         for (;;) {
  383                 /*
  384                  * XXX: This is not an ideal solution, but I belive it to
  385                  * XXX: deadlock safe, all things considered.
  386                  */
  387                 bp2 = g_clone_bio(bp);
  388                 if (bp2 != NULL)
  389                         break;
  390                 pause("gdstrat", hz / 10);
  391         }
  392         KASSERT(bp2 != NULL, ("XXX: ENOMEM in a bad place"));
  393         bp2->bio_done = g_dev_done;
  394         g_trace(G_T_BIO,
  395             "g_dev_strategy(%p/%p) offset %jd length %jd data %p cmd %d",
  396             bp, bp2, (intmax_t)bp->bio_offset, (intmax_t)bp2->bio_length,
  397             bp2->bio_data, bp2->bio_cmd);
  398         g_io_request(bp2, cp);
  399         KASSERT(cp->acr || cp->acw,
  400             ("g_dev_strategy raced with g_dev_close and lost"));
  401 
  402 }
  403 
  404 /*
  405  * g_dev_orphan()
  406  *
  407  * Called from below when the provider orphaned us.
  408  * - Clear any dump settings.
  409  * - Destroy the struct cdev *to prevent any more request from coming in.  The
  410  *   provider is already marked with an error, so anything which comes in
  411  *   in the interrim will be returned immediately.
  412  * - Wait for any outstanding I/O to finish.
  413  * - Set our access counts to zero, whatever they were.
  414  * - Detach and self-destruct.
  415  */
  416 
  417 static void
  418 g_dev_orphan(struct g_consumer *cp)
  419 {
  420         struct g_geom *gp;
  421         struct cdev *dev;
  422 
  423         g_topology_assert();
  424         gp = cp->geom;
  425         dev = gp->softc;
  426         g_trace(G_T_TOPOLOGY, "g_dev_orphan(%p(%s))", cp, gp->name);
  427 
  428         /* Reset any dump-area set on this device */
  429         if (dev->si_flags & SI_DUMPDEV)
  430                 set_dumper(NULL);
  431 
  432         /* Destroy the struct cdev *so we get no more requests */
  433         destroy_dev(dev);
  434 
  435         /* Wait for the cows to come home */
  436         while (cp->nstart != cp->nend)
  437                 pause("gdevorphan", hz / 10);
  438 
  439         if (cp->acr > 0 || cp->acw > 0 || cp->ace > 0)
  440                 g_access(cp, -cp->acr, -cp->acw, -cp->ace);
  441 
  442         g_detach(cp);
  443         g_destroy_consumer(cp);
  444         g_destroy_geom(gp);
  445 }
  446 
  447 DECLARE_GEOM_CLASS(g_dev_class, g_dev);

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