The Design and Implementation of the FreeBSD Operating System, Second Edition
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sys/geom/geom_subr.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("$FreeBSD$");
   38 
   39 #include "opt_ddb.h"
   40 
   41 #include <sys/param.h>
   42 #include <sys/systm.h>
   43 #include <sys/devicestat.h>
   44 #include <sys/kernel.h>
   45 #include <sys/malloc.h>
   46 #include <sys/bio.h>
   47 #include <sys/sysctl.h>
   48 #include <sys/proc.h>
   49 #include <sys/kthread.h>
   50 #include <sys/lock.h>
   51 #include <sys/mutex.h>
   52 #include <sys/errno.h>
   53 #include <sys/sbuf.h>
   54 #include <geom/geom.h>
   55 #include <geom/geom_int.h>
   56 #include <machine/stdarg.h>
   57 
   58 #ifdef DDB
   59 #include <ddb/ddb.h>
   60 #endif
   61 
   62 struct class_list_head g_classes = LIST_HEAD_INITIALIZER(g_classes);
   63 static struct g_tailq_head geoms = TAILQ_HEAD_INITIALIZER(geoms);
   64 char *g_wait_event, *g_wait_up, *g_wait_down, *g_wait_sim;
   65 
   66 struct g_hh00 {
   67         struct g_class  *mp;
   68         int             error;
   69         int             post;
   70 };
   71 
   72 /*
   73  * This event offers a new class a chance to taste all preexisting providers.
   74  */
   75 static void
   76 g_load_class(void *arg, int flag)
   77 {
   78         struct g_hh00 *hh;
   79         struct g_class *mp2, *mp;
   80         struct g_geom *gp;
   81         struct g_provider *pp;
   82 
   83         g_topology_assert();
   84         if (flag == EV_CANCEL)  /* XXX: can't happen ? */
   85                 return;
   86         if (g_shutdown)
   87                 return;
   88 
   89         hh = arg;
   90         mp = hh->mp;
   91         hh->error = 0;
   92         if (hh->post) {
   93                 g_free(hh);
   94                 hh = NULL;
   95         }
   96         g_trace(G_T_TOPOLOGY, "g_load_class(%s)", mp->name);
   97         KASSERT(mp->name != NULL && *mp->name != '\0',
   98             ("GEOM class has no name"));
   99         LIST_FOREACH(mp2, &g_classes, class) {
  100                 if (mp2 == mp) {
  101                         printf("The GEOM class %s is already loaded.\n",
  102                             mp2->name);
  103                         if (hh != NULL)
  104                                 hh->error = EEXIST;
  105                         return;
  106                 } else if (strcmp(mp2->name, mp->name) == 0) {
  107                         printf("A GEOM class %s is already loaded.\n",
  108                             mp2->name);
  109                         if (hh != NULL)
  110                                 hh->error = EEXIST;
  111                         return;
  112                 }
  113         }
  114 
  115         LIST_INIT(&mp->geom);
  116         LIST_INSERT_HEAD(&g_classes, mp, class);
  117         if (mp->init != NULL)
  118                 mp->init(mp);
  119         if (mp->taste == NULL)
  120                 return;
  121         LIST_FOREACH(mp2, &g_classes, class) {
  122                 if (mp == mp2)
  123                         continue;
  124                 LIST_FOREACH(gp, &mp2->geom, geom) {
  125                         LIST_FOREACH(pp, &gp->provider, provider) {
  126                                 mp->taste(mp, pp, 0);
  127                                 g_topology_assert();
  128                         }
  129                 }
  130         }
  131 }
  132 
  133 static void
  134 g_unload_class(void *arg, int flag)
  135 {
  136         struct g_hh00 *hh;
  137         struct g_class *mp;
  138         struct g_geom *gp;
  139         struct g_provider *pp;
  140         struct g_consumer *cp;
  141         int error;
  142 
  143         g_topology_assert();
  144         hh = arg;
  145         mp = hh->mp;
  146         G_VALID_CLASS(mp);
  147         g_trace(G_T_TOPOLOGY, "g_unload_class(%s)", mp->name);
  148 
  149         /*
  150          * We allow unloading if we have no geoms, or a class
  151          * method we can use to get rid of them.
  152          */
  153         if (!LIST_EMPTY(&mp->geom) && mp->destroy_geom == NULL) {
  154                 hh->error = EOPNOTSUPP;
  155                 return;
  156         }
  157 
  158         /* We refuse to unload if anything is open */
  159         LIST_FOREACH(gp, &mp->geom, geom) {
  160                 LIST_FOREACH(pp, &gp->provider, provider)
  161                         if (pp->acr || pp->acw || pp->ace) {
  162                                 hh->error = EBUSY;
  163                                 return;
  164                         }
  165                 LIST_FOREACH(cp, &gp->consumer, consumer)
  166                         if (cp->acr || cp->acw || cp->ace) {
  167                                 hh->error = EBUSY;
  168                                 return;
  169                         }
  170         }
  171 
  172         /* Bar new entries */
  173         mp->taste = NULL;
  174         mp->config = NULL;
  175 
  176         error = 0;
  177         for (;;) {
  178                 gp = LIST_FIRST(&mp->geom);
  179                 if (gp == NULL)
  180                         break;
  181                 error = mp->destroy_geom(NULL, mp, gp);
  182                 if (error != 0)
  183                         break;
  184         }
  185         if (error == 0) {
  186                 if (mp->fini != NULL)
  187                         mp->fini(mp);
  188                 LIST_REMOVE(mp, class);
  189         }
  190         hh->error = error;
  191         return;
  192 }
  193 
  194 int
  195 g_modevent(module_t mod, int type, void *data)
  196 {
  197         struct g_hh00 *hh;
  198         int error;
  199         static int g_ignition;
  200         struct g_class *mp;
  201 
  202         mp = data;
  203         if (mp->version != G_VERSION) {
  204                 printf("GEOM class %s has Wrong version %x\n",
  205                     mp->name, mp->version);
  206                 return (EINVAL);
  207         }
  208         if (!g_ignition) {
  209                 g_ignition++;
  210                 g_init();
  211         }
  212         hh = g_malloc(sizeof *hh, M_WAITOK | M_ZERO);
  213         hh->mp = data;
  214         error = EOPNOTSUPP;
  215         switch (type) {
  216         case MOD_LOAD:
  217                 g_trace(G_T_TOPOLOGY, "g_modevent(%s, LOAD)", hh->mp->name);
  218                 /*
  219                  * Once the system is not cold, MOD_LOAD calls will be
  220                  * from the userland and the g_event thread will be able
  221                  * to acknowledge their completion.
  222                  */
  223                 if (cold) {
  224                         hh->post = 1;
  225                         error = g_post_event(g_load_class, hh, M_WAITOK, NULL);
  226                 } else {
  227                         error = g_waitfor_event(g_load_class, hh, M_WAITOK,
  228                             NULL);
  229                         if (error == 0)
  230                                 error = hh->error;
  231                         g_free(hh);
  232                 }
  233                 break;
  234         case MOD_UNLOAD:
  235                 g_trace(G_T_TOPOLOGY, "g_modevent(%s, UNLOAD)", hh->mp->name);
  236                 error = g_waitfor_event(g_unload_class, hh, M_WAITOK, NULL);
  237                 if (error == 0)
  238                         error = hh->error;
  239                 if (error == 0) {
  240                         KASSERT(LIST_EMPTY(&hh->mp->geom),
  241                             ("Unloaded class (%s) still has geom", hh->mp->name));
  242                 }
  243                 g_free(hh);
  244                 break;
  245         default:
  246                 g_free(hh);
  247                 break;
  248         }
  249         return (error);
  250 }
  251 
  252 struct g_geom *
  253 g_new_geomf(struct g_class *mp, const char *fmt, ...)
  254 {
  255         struct g_geom *gp;
  256         va_list ap;
  257         struct sbuf *sb;
  258 
  259         g_topology_assert();
  260         G_VALID_CLASS(mp);
  261         sb = sbuf_new(NULL, NULL, 0, SBUF_AUTOEXTEND);
  262         va_start(ap, fmt);
  263         sbuf_vprintf(sb, fmt, ap);
  264         va_end(ap);
  265         sbuf_finish(sb);
  266         gp = g_malloc(sizeof *gp, M_WAITOK | M_ZERO);
  267         gp->name = g_malloc(sbuf_len(sb) + 1, M_WAITOK | M_ZERO);
  268         gp->class = mp;
  269         gp->rank = 1;
  270         LIST_INIT(&gp->consumer);
  271         LIST_INIT(&gp->provider);
  272         LIST_INSERT_HEAD(&mp->geom, gp, geom);
  273         TAILQ_INSERT_HEAD(&geoms, gp, geoms);
  274         strcpy(gp->name, sbuf_data(sb));
  275         sbuf_delete(sb);
  276         /* Fill in defaults from class */
  277         gp->start = mp->start;
  278         gp->spoiled = mp->spoiled;
  279         gp->dumpconf = mp->dumpconf;
  280         gp->access = mp->access;
  281         gp->orphan = mp->orphan;
  282         gp->ioctl = mp->ioctl;
  283         return (gp);
  284 }
  285 
  286 void
  287 g_destroy_geom(struct g_geom *gp)
  288 {
  289 
  290         g_topology_assert();
  291         G_VALID_GEOM(gp);
  292         g_trace(G_T_TOPOLOGY, "g_destroy_geom(%p(%s))", gp, gp->name);
  293         KASSERT(LIST_EMPTY(&gp->consumer),
  294             ("g_destroy_geom(%s) with consumer(s) [%p]",
  295             gp->name, LIST_FIRST(&gp->consumer)));
  296         KASSERT(LIST_EMPTY(&gp->provider),
  297             ("g_destroy_geom(%s) with provider(s) [%p]",
  298             gp->name, LIST_FIRST(&gp->provider)));
  299         g_cancel_event(gp);
  300         LIST_REMOVE(gp, geom);
  301         TAILQ_REMOVE(&geoms, gp, geoms);
  302         g_free(gp->name);
  303         g_free(gp);
  304 }
  305 
  306 /*
  307  * This function is called (repeatedly) until the has withered away.
  308  */
  309 void
  310 g_wither_geom(struct g_geom *gp, int error)
  311 {
  312         struct g_provider *pp;
  313 
  314         g_topology_assert();
  315         G_VALID_GEOM(gp);
  316         g_trace(G_T_TOPOLOGY, "g_wither_geom(%p(%s))", gp, gp->name);
  317         if (!(gp->flags & G_GEOM_WITHER)) {
  318                 gp->flags |= G_GEOM_WITHER;
  319                 LIST_FOREACH(pp, &gp->provider, provider)
  320                         if (!(pp->flags & G_PF_ORPHAN))
  321                                 g_orphan_provider(pp, error);
  322         }
  323         g_do_wither();
  324 }
  325 
  326 /*
  327  * Convenience function to destroy a particular provider.
  328  */
  329 void
  330 g_wither_provider(struct g_provider *pp, int error)
  331 {
  332 
  333         pp->flags |= G_PF_WITHER;
  334         if (!(pp->flags & G_PF_ORPHAN))
  335                 g_orphan_provider(pp, error);
  336 }
  337 
  338 /*
  339  * This function is called (repeatedly) until the has withered away.
  340  */
  341 void
  342 g_wither_geom_close(struct g_geom *gp, int error)
  343 {
  344         struct g_consumer *cp;
  345 
  346         g_topology_assert();
  347         G_VALID_GEOM(gp);
  348         g_trace(G_T_TOPOLOGY, "g_wither_geom_close(%p(%s))", gp, gp->name);
  349         LIST_FOREACH(cp, &gp->consumer, consumer)
  350                 if (cp->acr || cp->acw || cp->ace)
  351                         g_access(cp, -cp->acr, -cp->acw, -cp->ace);
  352         g_wither_geom(gp, error);
  353 }
  354 
  355 /*
  356  * This function is called (repeatedly) until we cant wash away more
  357  * withered bits at present.  Return value contains two bits.  Bit 0
  358  * set means "withering stuff we can't wash now", bit 1 means "call
  359  * me again, there may be stuff I didn't get the first time around.
  360  */
  361 int
  362 g_wither_washer()
  363 {
  364         struct g_class *mp;
  365         struct g_geom *gp, *gp2;
  366         struct g_provider *pp, *pp2;
  367         struct g_consumer *cp, *cp2;
  368         int result;
  369 
  370         result = 0;
  371         g_topology_assert();
  372         LIST_FOREACH(mp, &g_classes, class) {
  373                 LIST_FOREACH_SAFE(gp, &mp->geom, geom, gp2) {
  374                         LIST_FOREACH_SAFE(pp, &gp->provider, provider, pp2) {
  375                                 if (!(pp->flags & G_PF_WITHER))
  376                                         continue;
  377                                 if (LIST_EMPTY(&pp->consumers))
  378                                         g_destroy_provider(pp);
  379                                 else
  380                                         result |= 1;
  381                         }
  382                         if (!(gp->flags & G_GEOM_WITHER))
  383                                 continue;
  384                         LIST_FOREACH_SAFE(pp, &gp->provider, provider, pp2) {
  385                                 if (LIST_EMPTY(&pp->consumers))
  386                                         g_destroy_provider(pp);
  387                                 else
  388                                         result |= 1;
  389                         }
  390                         LIST_FOREACH_SAFE(cp, &gp->consumer, consumer, cp2) {
  391                                 if (cp->acr || cp->acw || cp->ace) {
  392                                         result |= 1;
  393                                         continue;
  394                                 }
  395                                 if (cp->provider != NULL)
  396                                         g_detach(cp);
  397                                 g_destroy_consumer(cp);
  398                                 result |= 2;
  399                         }
  400                         if (LIST_EMPTY(&gp->provider) &&
  401                             LIST_EMPTY(&gp->consumer))
  402                                 g_destroy_geom(gp);
  403                         else
  404                                 result |= 1;
  405                 }
  406         }
  407         return (result);
  408 }
  409 
  410 struct g_consumer *
  411 g_new_consumer(struct g_geom *gp)
  412 {
  413         struct g_consumer *cp;
  414 
  415         g_topology_assert();
  416         G_VALID_GEOM(gp);
  417         KASSERT(!(gp->flags & G_GEOM_WITHER),
  418             ("g_new_consumer on WITHERing geom(%s) (class %s)",
  419             gp->name, gp->class->name));
  420         KASSERT(gp->orphan != NULL,
  421             ("g_new_consumer on geom(%s) (class %s) without orphan",
  422             gp->name, gp->class->name));
  423 
  424         cp = g_malloc(sizeof *cp, M_WAITOK | M_ZERO);
  425         cp->geom = gp;
  426         cp->stat = devstat_new_entry(cp, -1, 0, DEVSTAT_ALL_SUPPORTED,
  427             DEVSTAT_TYPE_DIRECT, DEVSTAT_PRIORITY_MAX);
  428         LIST_INSERT_HEAD(&gp->consumer, cp, consumer);
  429         return(cp);
  430 }
  431 
  432 void
  433 g_destroy_consumer(struct g_consumer *cp)
  434 {
  435         struct g_geom *gp;
  436 
  437         g_topology_assert();
  438         G_VALID_CONSUMER(cp);
  439         g_trace(G_T_TOPOLOGY, "g_destroy_consumer(%p)", cp);
  440         KASSERT (cp->provider == NULL, ("g_destroy_consumer but attached"));
  441         KASSERT (cp->acr == 0, ("g_destroy_consumer with acr"));
  442         KASSERT (cp->acw == 0, ("g_destroy_consumer with acw"));
  443         KASSERT (cp->ace == 0, ("g_destroy_consumer with ace"));
  444         g_cancel_event(cp);
  445         gp = cp->geom;
  446         LIST_REMOVE(cp, consumer);
  447         devstat_remove_entry(cp->stat);
  448         g_free(cp);
  449         if (gp->flags & G_GEOM_WITHER)
  450                 g_do_wither();
  451 }
  452 
  453 static void
  454 g_new_provider_event(void *arg, int flag)
  455 {
  456         struct g_class *mp;
  457         struct g_provider *pp;
  458         struct g_consumer *cp;
  459         int i;
  460 
  461         g_topology_assert();
  462         if (flag == EV_CANCEL)
  463                 return;
  464         if (g_shutdown)
  465                 return;
  466         pp = arg;
  467         G_VALID_PROVIDER(pp);
  468         LIST_FOREACH(mp, &g_classes, class) {
  469                 if (mp->taste == NULL)
  470                         continue;
  471                 i = 1;
  472                 LIST_FOREACH(cp, &pp->consumers, consumers)
  473                         if (cp->geom->class == mp)
  474                                 i = 0;
  475                 if (!i)
  476                         continue;
  477                 mp->taste(mp, pp, 0);
  478                 g_topology_assert();
  479         }
  480 }
  481 
  482 
  483 struct g_provider *
  484 g_new_providerf(struct g_geom *gp, const char *fmt, ...)
  485 {
  486         struct g_provider *pp;
  487         struct sbuf *sb;
  488         va_list ap;
  489 
  490         g_topology_assert();
  491         G_VALID_GEOM(gp);
  492         KASSERT(gp->access != NULL,
  493             ("new provider on geom(%s) without ->access (class %s)",
  494             gp->name, gp->class->name));
  495         KASSERT(gp->start != NULL,
  496             ("new provider on geom(%s) without ->start (class %s)",
  497             gp->name, gp->class->name));
  498         KASSERT(!(gp->flags & G_GEOM_WITHER),
  499             ("new provider on WITHERing geom(%s) (class %s)",
  500             gp->name, gp->class->name));
  501         sb = sbuf_new(NULL, NULL, 0, SBUF_AUTOEXTEND);
  502         va_start(ap, fmt);
  503         sbuf_vprintf(sb, fmt, ap);
  504         va_end(ap);
  505         sbuf_finish(sb);
  506         pp = g_malloc(sizeof *pp + sbuf_len(sb) + 1, M_WAITOK | M_ZERO);
  507         pp->name = (char *)(pp + 1);
  508         strcpy(pp->name, sbuf_data(sb));
  509         sbuf_delete(sb);
  510         LIST_INIT(&pp->consumers);
  511         pp->error = ENXIO;
  512         pp->geom = gp;
  513         pp->stat = devstat_new_entry(pp, -1, 0, DEVSTAT_ALL_SUPPORTED,
  514             DEVSTAT_TYPE_DIRECT, DEVSTAT_PRIORITY_MAX);
  515         LIST_INSERT_HEAD(&gp->provider, pp, provider);
  516         g_post_event(g_new_provider_event, pp, M_WAITOK, pp, gp, NULL);
  517         return (pp);
  518 }
  519 
  520 void
  521 g_error_provider(struct g_provider *pp, int error)
  522 {
  523 
  524         /* G_VALID_PROVIDER(pp);  We may not have g_topology */
  525         pp->error = error;
  526 }
  527 
  528 struct g_provider *
  529 g_provider_by_name(char const *arg)
  530 {
  531         struct g_class *cp;
  532         struct g_geom *gp;
  533         struct g_provider *pp;
  534 
  535         LIST_FOREACH(cp, &g_classes, class) {
  536                 LIST_FOREACH(gp, &cp->geom, geom) {
  537                         LIST_FOREACH(pp, &gp->provider, provider) {
  538                                 if (!strcmp(arg, pp->name))
  539                                         return (pp);
  540                         }
  541                 }
  542         }
  543         return (NULL);
  544 }
  545 
  546 void
  547 g_destroy_provider(struct g_provider *pp)
  548 {
  549         struct g_geom *gp;
  550 
  551         g_topology_assert();
  552         G_VALID_PROVIDER(pp);
  553         KASSERT(LIST_EMPTY(&pp->consumers),
  554             ("g_destroy_provider but attached"));
  555         KASSERT (pp->acr == 0, ("g_destroy_provider with acr"));
  556         KASSERT (pp->acw == 0, ("g_destroy_provider with acw"));
  557         KASSERT (pp->acw == 0, ("g_destroy_provider with ace"));
  558         g_cancel_event(pp);
  559         LIST_REMOVE(pp, provider);
  560         gp = pp->geom;
  561         devstat_remove_entry(pp->stat);
  562         g_free(pp);
  563         if ((gp->flags & G_GEOM_WITHER))
  564                 g_do_wither();
  565 }
  566 
  567 /*
  568  * We keep the "geoms" list sorted by topological order (== increasing
  569  * numerical rank) at all times.
  570  * When an attach is done, the attaching geoms rank is invalidated
  571  * and it is moved to the tail of the list.
  572  * All geoms later in the sequence has their ranks reevaluated in
  573  * sequence.  If we cannot assign rank to a geom because it's
  574  * prerequisites do not have rank, we move that element to the tail
  575  * of the sequence with invalid rank as well.
  576  * At some point we encounter our original geom and if we stil fail
  577  * to assign it a rank, there must be a loop and we fail back to
  578  * g_attach() which detach again and calls redo_rank again
  579  * to fix up the damage.
  580  * It would be much simpler code wise to do it recursively, but we
  581  * can't risk that on the kernel stack.
  582  */
  583 
  584 static int
  585 redo_rank(struct g_geom *gp)
  586 {
  587         struct g_consumer *cp;
  588         struct g_geom *gp1, *gp2;
  589         int n, m;
  590 
  591         g_topology_assert();
  592         G_VALID_GEOM(gp);
  593 
  594         /* Invalidate this geoms rank and move it to the tail */
  595         gp1 = TAILQ_NEXT(gp, geoms);
  596         if (gp1 != NULL) {
  597                 gp->rank = 0;
  598                 TAILQ_REMOVE(&geoms, gp, geoms);
  599                 TAILQ_INSERT_TAIL(&geoms, gp, geoms);
  600         } else {
  601                 gp1 = gp;
  602         }
  603 
  604         /* re-rank the rest of the sequence */
  605         for (; gp1 != NULL; gp1 = gp2) {
  606                 gp1->rank = 0;
  607                 m = 1;
  608                 LIST_FOREACH(cp, &gp1->consumer, consumer) {
  609                         if (cp->provider == NULL)
  610                                 continue;
  611                         n = cp->provider->geom->rank;
  612                         if (n == 0) {
  613                                 m = 0;
  614                                 break;
  615                         } else if (n >= m)
  616                                 m = n + 1;
  617                 }
  618                 gp1->rank = m;
  619                 gp2 = TAILQ_NEXT(gp1, geoms);
  620 
  621                 /* got a rank, moving on */
  622                 if (m != 0)
  623                         continue;
  624 
  625                 /* no rank to original geom means loop */
  626                 if (gp == gp1) 
  627                         return (ELOOP);
  628 
  629                 /* no rank, put it at the end move on */
  630                 TAILQ_REMOVE(&geoms, gp1, geoms);
  631                 TAILQ_INSERT_TAIL(&geoms, gp1, geoms);
  632         }
  633         return (0);
  634 }
  635 
  636 int
  637 g_attach(struct g_consumer *cp, struct g_provider *pp)
  638 {
  639         int error;
  640 
  641         g_topology_assert();
  642         G_VALID_CONSUMER(cp);
  643         G_VALID_PROVIDER(pp);
  644         KASSERT(cp->provider == NULL, ("attach but attached"));
  645         cp->provider = pp;
  646         LIST_INSERT_HEAD(&pp->consumers, cp, consumers);
  647         error = redo_rank(cp->geom);
  648         if (error) {
  649                 LIST_REMOVE(cp, consumers);
  650                 cp->provider = NULL;
  651                 redo_rank(cp->geom);
  652         }
  653         return (error);
  654 }
  655 
  656 void
  657 g_detach(struct g_consumer *cp)
  658 {
  659         struct g_provider *pp;
  660 
  661         g_topology_assert();
  662         G_VALID_CONSUMER(cp);
  663         g_trace(G_T_TOPOLOGY, "g_detach(%p)", cp);
  664         KASSERT(cp->provider != NULL, ("detach but not attached"));
  665         KASSERT(cp->acr == 0, ("detach but nonzero acr"));
  666         KASSERT(cp->acw == 0, ("detach but nonzero acw"));
  667         KASSERT(cp->ace == 0, ("detach but nonzero ace"));
  668         KASSERT(cp->nstart == cp->nend,
  669             ("detach with active requests"));
  670         pp = cp->provider;
  671         LIST_REMOVE(cp, consumers);
  672         cp->provider = NULL;
  673         if (pp->geom->flags & G_GEOM_WITHER)
  674                 g_do_wither();
  675         else if (pp->flags & G_PF_WITHER)
  676                 g_do_wither();
  677         redo_rank(cp->geom);
  678 }
  679 
  680 /*
  681  * g_access()
  682  *
  683  * Access-check with delta values.  The question asked is "can provider
  684  * "cp" change the access counters by the relative amounts dc[rwe] ?"
  685  */
  686 
  687 int
  688 g_access(struct g_consumer *cp, int dcr, int dcw, int dce)
  689 {
  690         struct g_provider *pp;
  691         int pr,pw,pe;
  692         int error;
  693 
  694         g_topology_assert();
  695         G_VALID_CONSUMER(cp);
  696         pp = cp->provider;
  697         KASSERT(pp != NULL, ("access but not attached"));
  698         G_VALID_PROVIDER(pp);
  699 
  700         g_trace(G_T_ACCESS, "g_access(%p(%s), %d, %d, %d)",
  701             cp, pp->name, dcr, dcw, dce);
  702 
  703         KASSERT(cp->acr + dcr >= 0, ("access resulting in negative acr"));
  704         KASSERT(cp->acw + dcw >= 0, ("access resulting in negative acw"));
  705         KASSERT(cp->ace + dce >= 0, ("access resulting in negative ace"));
  706         KASSERT(dcr != 0 || dcw != 0 || dce != 0, ("NOP access request"));
  707         KASSERT(pp->geom->access != NULL, ("NULL geom->access"));
  708 
  709         /*
  710          * If our class cares about being spoiled, and we have been, we
  711          * are probably just ahead of the event telling us that.  Fail
  712          * now rather than having to unravel this later.
  713          */
  714         if (cp->geom->spoiled != NULL && cp->spoiled &&
  715             (dcr > 0 || dcw > 0 || dce > 0))
  716                 return (ENXIO);
  717 
  718         /*
  719          * Figure out what counts the provider would have had, if this
  720          * consumer had (r0w0e0) at this time.
  721          */
  722         pr = pp->acr - cp->acr;
  723         pw = pp->acw - cp->acw;
  724         pe = pp->ace - cp->ace;
  725 
  726         g_trace(G_T_ACCESS,
  727     "open delta:[r%dw%de%d] old:[r%dw%de%d] provider:[r%dw%de%d] %p(%s)",
  728             dcr, dcw, dce,
  729             cp->acr, cp->acw, cp->ace,
  730             pp->acr, pp->acw, pp->ace,
  731             pp, pp->name);
  732 
  733         /* If foot-shooting is enabled, any open on rank#1 is OK */
  734         if ((g_debugflags & 16) && pp->geom->rank == 1)
  735                 ;
  736         /* If we try exclusive but already write: fail */
  737         else if (dce > 0 && pw > 0)
  738                 return (EPERM);
  739         /* If we try write but already exclusive: fail */
  740         else if (dcw > 0 && pe > 0)
  741                 return (EPERM);
  742         /* If we try to open more but provider is error'ed: fail */
  743         else if ((dcr > 0 || dcw > 0 || dce > 0) && pp->error != 0)
  744                 return (pp->error);
  745 
  746         /* Ok then... */
  747 
  748         error = pp->geom->access(pp, dcr, dcw, dce);
  749         KASSERT(dcr > 0 || dcw > 0 || dce > 0 || error == 0,
  750             ("Geom provider %s::%s failed closing ->access()",
  751             pp->geom->class->name, pp->name));
  752         if (!error) {
  753                 /*
  754                  * If we open first write, spoil any partner consumers.
  755                  * If we close last write and provider is not errored,
  756                  * trigger re-taste.
  757                  */
  758                 if (pp->acw == 0 && dcw != 0)
  759                         g_spoil(pp, cp);
  760                 else if (pp->acw != 0 && pp->acw == -dcw && pp->error == 0 &&
  761                     !(pp->geom->flags & G_GEOM_WITHER))
  762                         g_post_event(g_new_provider_event, pp, M_WAITOK, 
  763                             pp, NULL);
  764 
  765                 pp->acr += dcr;
  766                 pp->acw += dcw;
  767                 pp->ace += dce;
  768                 cp->acr += dcr;
  769                 cp->acw += dcw;
  770                 cp->ace += dce;
  771                 if (pp->acr != 0 || pp->acw != 0 || pp->ace != 0)
  772                         KASSERT(pp->sectorsize > 0,
  773                             ("Provider %s lacks sectorsize", pp->name));
  774         }
  775         return (error);
  776 }
  777 
  778 int
  779 g_handleattr_int(struct bio *bp, const char *attribute, int val)
  780 {
  781 
  782         return (g_handleattr(bp, attribute, &val, sizeof val));
  783 }
  784 
  785 int
  786 g_handleattr_off_t(struct bio *bp, const char *attribute, off_t val)
  787 {
  788 
  789         return (g_handleattr(bp, attribute, &val, sizeof val));
  790 }
  791 
  792 int
  793 g_handleattr_str(struct bio *bp, const char *attribute, char *str)
  794 {
  795 
  796         return (g_handleattr(bp, attribute, str, 0));
  797 }
  798 
  799 int
  800 g_handleattr(struct bio *bp, const char *attribute, void *val, int len)
  801 {
  802         int error = 0;
  803 
  804         if (strcmp(bp->bio_attribute, attribute))
  805                 return (0);
  806         if (len == 0) {
  807                 bzero(bp->bio_data, bp->bio_length);
  808                 if (strlcpy(bp->bio_data, val, bp->bio_length) >=
  809                     bp->bio_length) {
  810                         printf("%s: %s bio_length %jd len %zu -> EFAULT\n",
  811                             __func__, bp->bio_to->name,
  812                             (intmax_t)bp->bio_length, strlen(val));
  813                         error = EFAULT;
  814                 }
  815         } else if (bp->bio_length == len) {
  816                 bcopy(val, bp->bio_data, len);
  817                 bp->bio_completed = len;
  818         } else {
  819                 printf("%s: %s bio_length %jd len %d -> EFAULT\n", __func__,
  820                     bp->bio_to->name, (intmax_t)bp->bio_length, len);
  821                 error = EFAULT;
  822         }
  823         g_io_deliver(bp, error);
  824         return (1);
  825 }
  826 
  827 int
  828 g_std_access(struct g_provider *pp,
  829         int dr __unused, int dw __unused, int de __unused)
  830 {
  831 
  832         g_topology_assert();
  833         G_VALID_PROVIDER(pp);
  834         return (0);
  835 }
  836 
  837 void
  838 g_std_done(struct bio *bp)
  839 {
  840         struct bio *bp2;
  841 
  842         bp2 = bp->bio_parent;
  843         if (bp2->bio_error == 0)
  844                 bp2->bio_error = bp->bio_error;
  845         bp2->bio_completed += bp->bio_completed;
  846         g_destroy_bio(bp);
  847         bp2->bio_inbed++;
  848         if (bp2->bio_children == bp2->bio_inbed)
  849                 g_io_deliver(bp2, bp2->bio_error);
  850 }
  851 
  852 /* XXX: maybe this is only g_slice_spoiled */
  853 
  854 void
  855 g_std_spoiled(struct g_consumer *cp)
  856 {
  857         struct g_geom *gp;
  858         struct g_provider *pp;
  859 
  860         g_topology_assert();
  861         G_VALID_CONSUMER(cp);
  862         g_trace(G_T_TOPOLOGY, "g_std_spoiled(%p)", cp);
  863         g_detach(cp);
  864         gp = cp->geom;
  865         LIST_FOREACH(pp, &gp->provider, provider)
  866                 g_orphan_provider(pp, ENXIO);
  867         g_destroy_consumer(cp);
  868         if (LIST_EMPTY(&gp->provider) && LIST_EMPTY(&gp->consumer))
  869                 g_destroy_geom(gp);
  870         else
  871                 gp->flags |= G_GEOM_WITHER;
  872 }
  873 
  874 /*
  875  * Spoiling happens when a provider is opened for writing, but consumers
  876  * which are configured by in-band data are attached (slicers for instance).
  877  * Since the write might potentially change the in-band data, such consumers
  878  * need to re-evaluate their existence after the writing session closes.
  879  * We do this by (offering to) tear them down when the open for write happens
  880  * in return for a re-taste when it closes again.
  881  * Together with the fact that such consumers grab an 'e' bit whenever they
  882  * are open, regardless of mode, this ends up DTRT.
  883  */
  884 
  885 static void
  886 g_spoil_event(void *arg, int flag)
  887 {
  888         struct g_provider *pp;
  889         struct g_consumer *cp, *cp2;
  890 
  891         g_topology_assert();
  892         if (flag == EV_CANCEL)
  893                 return;
  894         pp = arg;
  895         G_VALID_PROVIDER(pp);
  896         for (cp = LIST_FIRST(&pp->consumers); cp != NULL; cp = cp2) {
  897                 cp2 = LIST_NEXT(cp, consumers);
  898                 if (!cp->spoiled)
  899                         continue;
  900                 cp->spoiled = 0;
  901                 if (cp->geom->spoiled == NULL)
  902                         continue;
  903                 cp->geom->spoiled(cp);
  904                 g_topology_assert();
  905         }
  906 }
  907 
  908 void
  909 g_spoil(struct g_provider *pp, struct g_consumer *cp)
  910 {
  911         struct g_consumer *cp2;
  912 
  913         g_topology_assert();
  914         G_VALID_PROVIDER(pp);
  915         G_VALID_CONSUMER(cp);
  916 
  917         LIST_FOREACH(cp2, &pp->consumers, consumers) {
  918                 if (cp2 == cp)
  919                         continue;
  920 /*
  921                 KASSERT(cp2->acr == 0, ("spoiling cp->acr = %d", cp2->acr));
  922                 KASSERT(cp2->acw == 0, ("spoiling cp->acw = %d", cp2->acw));
  923 */
  924                 KASSERT(cp2->ace == 0, ("spoiling cp->ace = %d", cp2->ace));
  925                 cp2->spoiled++;
  926         }
  927         g_post_event(g_spoil_event, pp, M_WAITOK, pp, NULL);
  928 }
  929 
  930 int
  931 g_getattr__(const char *attr, struct g_consumer *cp, void *var, int len)
  932 {
  933         int error, i;
  934 
  935         i = len;
  936         error = g_io_getattr(attr, cp, &i, var);
  937         if (error)
  938                 return (error);
  939         if (i != len)
  940                 return (EINVAL);
  941         return (0);
  942 }
  943 
  944 #if defined(DIAGNOSTIC) || defined(DDB)
  945 /*
  946  * This function walks (topologically unsafely) the mesh and return a
  947  * non-zero integer if it finds the argument pointer is an object.
  948  * The return value indicates which type of object it is belived to be.
  949  * If topology is not locked, this function is potentially dangerous,
  950  * but since it is for debugging purposes and can be useful for instance
  951  * from DDB, we do not assert topology lock is held.
  952  */
  953 int
  954 g_valid_obj(void const *ptr)
  955 {
  956         struct g_class *mp;
  957         struct g_geom *gp;
  958         struct g_consumer *cp;
  959         struct g_provider *pp;
  960 
  961         LIST_FOREACH(mp, &g_classes, class) {
  962                 if (ptr == mp)
  963                         return (1);
  964                 LIST_FOREACH(gp, &mp->geom, geom) {
  965                         if (ptr == gp)
  966                                 return (2);
  967                         LIST_FOREACH(cp, &gp->consumer, consumer)
  968                                 if (ptr == cp)
  969                                         return (3);
  970                         LIST_FOREACH(pp, &gp->provider, provider)
  971                                 if (ptr == pp)
  972                                         return (4);
  973                 }
  974         }
  975         return(0);
  976 }
  977 #endif
  978 
  979 #ifdef DDB
  980 
  981 #define gprintf(...)    do {                                            \
  982         printf("%*s", indent, "");                                      \
  983         printf(__VA_ARGS__);                                            \
  984 } while (0)
  985 #define gprintln(...)   do {                                            \
  986         gprintf(__VA_ARGS__);                                           \
  987         printf("\n");                                                   \
  988 } while (0)
  989 
  990 #define ADDFLAG(obj, flag, sflag)       do {                            \
  991         if ((obj)->flags & (flag)) {                                    \
  992                 if (comma)                                              \
  993                         strlcat(str, ",", size);                        \
  994                 strlcat(str, (sflag), size);                            \
  995                 comma = 1;                                              \
  996         }                                                               \
  997 } while (0)
  998 
  999 static char *
 1000 provider_flags_to_string(struct g_provider *pp, char *str, size_t size)
 1001 {
 1002         int comma = 0;
 1003 
 1004         bzero(str, size);
 1005         if (pp->flags == 0) {
 1006                 strlcpy(str, "NONE", size);
 1007                 return (str);
 1008         }
 1009         ADDFLAG(pp, G_PF_CANDELETE, "G_PF_CANDELETE");
 1010         ADDFLAG(pp, G_PF_WITHER, "G_PF_WITHER");
 1011         ADDFLAG(pp, G_PF_ORPHAN, "G_PF_ORPHAN");
 1012         return (str);
 1013 }
 1014 
 1015 static char *
 1016 geom_flags_to_string(struct g_geom *gp, char *str, size_t size)
 1017 {
 1018         int comma = 0;
 1019 
 1020         bzero(str, size);
 1021         if (gp->flags == 0) {
 1022                 strlcpy(str, "NONE", size);
 1023                 return (str);
 1024         }
 1025         ADDFLAG(gp, G_GEOM_WITHER, "G_GEOM_WITHER");
 1026         return (str);
 1027 }
 1028 static void
 1029 db_show_geom_consumer(int indent, struct g_consumer *cp)
 1030 {
 1031 
 1032         if (indent == 0) {
 1033                 gprintln("consumer: %p", cp);
 1034                 gprintln("  class:    %s (%p)", cp->geom->class->name,
 1035                     cp->geom->class);
 1036                 gprintln("  geom:     %s (%p)", cp->geom->name, cp->geom);
 1037                 if (cp->provider == NULL)
 1038                         gprintln("  provider: none");
 1039                 else {
 1040                         gprintln("  provider: %s (%p)", cp->provider->name,
 1041                             cp->provider);
 1042                 }
 1043                 gprintln("  access:   r%dw%de%d", cp->acr, cp->acw, cp->ace);
 1044                 gprintln("  spoiled:  %d", cp->spoiled);
 1045                 gprintln("  nstart:   %u", cp->nstart);
 1046                 gprintln("  nend:     %u", cp->nend);
 1047         } else {
 1048                 gprintf("consumer: %p (%s), access=r%dw%de%d", cp,
 1049                     cp->provider != NULL ? cp->provider->name : "none",
 1050                     cp->acr, cp->acw, cp->ace);
 1051                 if (cp->spoiled)
 1052                         printf(", spoiled=%d", cp->spoiled);
 1053                 printf("\n");
 1054         }
 1055 }
 1056 
 1057 static void
 1058 db_show_geom_provider(int indent, struct g_provider *pp)
 1059 {
 1060         struct g_consumer *cp;
 1061         char flags[64];
 1062 
 1063         if (indent == 0) {
 1064                 gprintln("provider: %s (%p)", pp->name, pp);
 1065                 gprintln("  class:        %s (%p)", pp->geom->class->name,
 1066                     pp->geom->class);
 1067                 gprintln("  geom:         %s (%p)", pp->geom->name, pp->geom);
 1068                 gprintln("  mediasize:    %jd", (intmax_t)pp->mediasize);
 1069                 gprintln("  sectorsize:   %u", pp->sectorsize);
 1070                 gprintln("  stripesize:   %u", pp->stripesize);
 1071                 gprintln("  stripeoffset: %u", pp->stripeoffset);
 1072                 gprintln("  access:       r%dw%de%d", pp->acr, pp->acw,
 1073                     pp->ace);
 1074                 gprintln("  flags:        %s (0x%04x)",
 1075                     provider_flags_to_string(pp, flags, sizeof(flags)),
 1076                     pp->flags);
 1077                 gprintln("  error:        %d", pp->error);
 1078                 gprintln("  nstart:       %u", pp->nstart);
 1079                 gprintln("  nend:         %u", pp->nend);
 1080                 if (LIST_EMPTY(&pp->consumers))
 1081                         gprintln("  consumers:    none");
 1082         } else {
 1083                 gprintf("provider: %s (%p), access=r%dw%de%d",
 1084                     pp->name, pp, pp->acr, pp->acw, pp->ace);
 1085                 if (pp->flags != 0) {
 1086                         printf(", flags=%s (0x%04x)",
 1087                             provider_flags_to_string(pp, flags, sizeof(flags)),
 1088                             pp->flags);
 1089                 }
 1090                 printf("\n");
 1091         }
 1092         if (!LIST_EMPTY(&pp->consumers)) {
 1093                 LIST_FOREACH(cp, &pp->consumers, consumers)
 1094                         db_show_geom_consumer(indent + 2, cp);
 1095         }
 1096 }
 1097 
 1098 static void
 1099 db_show_geom_geom(int indent, struct g_geom *gp)
 1100 {
 1101         struct g_provider *pp;
 1102         struct g_consumer *cp;
 1103         char flags[64];
 1104 
 1105         if (indent == 0) {
 1106                 gprintln("geom: %s (%p)", gp->name, gp);
 1107                 gprintln("  class:     %s (%p)", gp->class->name, gp->class);
 1108                 gprintln("  flags:     %s (0x%04x)",
 1109                     geom_flags_to_string(gp, flags, sizeof(flags)), gp->flags);
 1110                 gprintln("  rank:      %d", gp->rank);
 1111                 if (LIST_EMPTY(&gp->provider))
 1112                         gprintln("  providers: none");
 1113                 if (LIST_EMPTY(&gp->consumer))
 1114                         gprintln("  consumers: none");
 1115         } else {
 1116                 gprintf("geom: %s (%p), rank=%d", gp->name, gp, gp->rank);
 1117                 if (gp->flags != 0) {
 1118                         printf(", flags=%s (0x%04x)",
 1119                             geom_flags_to_string(gp, flags, sizeof(flags)),
 1120                             gp->flags);
 1121                 }
 1122                 printf("\n");
 1123         }
 1124         if (!LIST_EMPTY(&gp->provider)) {
 1125                 LIST_FOREACH(pp, &gp->provider, provider)
 1126                         db_show_geom_provider(indent + 2, pp);
 1127         }
 1128         if (!LIST_EMPTY(&gp->consumer)) {
 1129                 LIST_FOREACH(cp, &gp->consumer, consumer)
 1130                         db_show_geom_consumer(indent + 2, cp);
 1131         }
 1132 }
 1133 
 1134 static void
 1135 db_show_geom_class(struct g_class *mp)
 1136 {
 1137         struct g_geom *gp;
 1138 
 1139         printf("class: %s (%p)\n", mp->name, mp);
 1140         LIST_FOREACH(gp, &mp->geom, geom)
 1141                 db_show_geom_geom(2, gp);
 1142 }
 1143 
 1144 /*
 1145  * Print the GEOM topology or the given object.
 1146  */
 1147 DB_SHOW_COMMAND(geom, db_show_geom)
 1148 {
 1149         struct g_class *mp;
 1150 
 1151         if (!have_addr) {
 1152                 /* No address given, print the entire topology. */
 1153                 LIST_FOREACH(mp, &g_classes, class) {
 1154                         db_show_geom_class(mp);
 1155                         printf("\n");
 1156                 }
 1157         } else {
 1158                 switch (g_valid_obj((void *)addr)) {
 1159                 case 1:
 1160                         db_show_geom_class((struct g_class *)addr);
 1161                         break;
 1162                 case 2:
 1163                         db_show_geom_geom(0, (struct g_geom *)addr);
 1164                         break;
 1165                 case 3:
 1166                         db_show_geom_consumer(0, (struct g_consumer *)addr);
 1167                         break;
 1168                 case 4:
 1169                         db_show_geom_provider(0, (struct g_provider *)addr);
 1170                         break;
 1171                 default:
 1172                         printf("Not a GEOM object.\n");
 1173                         break;
 1174                 }
 1175         }
 1176 }
 1177 
 1178 #undef  gprintf
 1179 #undef  gprintln
 1180 #undef  ADDFLAG
 1181 
 1182 #endif  /* DDB */

Cache object: 6a8626d4cd499c1076a28cc0b67d978f


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