sys/geom/virstor/g_virstor.c

   1 /*-
   2  * Copyright (c) 2006-2007 Ivan Voras <ivoras@freebsd.org>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  */
  26
  27 /* Implementation notes:
  28  * - "Components" are wrappers around providers that make up the
  29  *   virtual storage (i.e. a virstor has "physical" components)
  30  */
  31
  32 #include <sys/cdefs.h>
  33 __FBSDID("$FreeBSD$");
  34
  35 #include <sys/param.h>
  36 #include <sys/systm.h>
  37 #include <sys/kernel.h>
  38 #include <sys/module.h>
  39 #include <sys/lock.h>
  40 #include <sys/mutex.h>
  41 #include <sys/sx.h>
  42 #include <sys/bio.h>
  43 #include <sys/sysctl.h>
  44 #include <sys/malloc.h>
  45 #include <sys/time.h>
  46 #include <sys/proc.h>
  47 #include <sys/kthread.h>
  48 #include <sys/mutex.h>
  49 #include <vm/uma.h>
  50 #include <geom/geom.h>
  51
  52 #include <geom/virstor/g_virstor.h>
  53 #include <geom/virstor/g_virstor_md.h>
  54
  55 /* Declare malloc(9) label */
  56 static MALLOC_DEFINE(M_GVIRSTOR, "gvirstor", "GEOM_VIRSTOR Data");
  57
  58 /* GEOM class methods */
  59 static g_init_t g_virstor_init;
  60 static g_fini_t g_virstor_fini;
  61 static g_taste_t g_virstor_taste;
  62 static g_ctl_req_t g_virstor_config;
  63 static g_ctl_destroy_geom_t g_virstor_destroy_geom;
  64
  65 /* Declare & initialize class structure ("geom class") */
  66 struct g_class g_virstor_class = {
  67         .name =         G_VIRSTOR_CLASS_NAME,
  68         .version =      G_VERSION,
  69         .init =         g_virstor_init,
  70         .fini =         g_virstor_fini,
  71         .taste =        g_virstor_taste,
  72         .ctlreq =       g_virstor_config,
  73         .destroy_geom = g_virstor_destroy_geom
  74         /* The .dumpconf and the rest are only usable for a geom instance, so
  75          * they will be set when such instance is created. */
  76 };
  77
  78 /* Declare sysctl's and loader tunables */
  79 SYSCTL_DECL(_kern_geom);
  80 SYSCTL_NODE(_kern_geom, OID_AUTO, virstor, CTLFLAG_RW, 0, "GEOM_GVIRSTOR information");
  81
  82 static u_int g_virstor_debug = 2; /* XXX: lower to 2 when released to public */
  83 TUNABLE_INT("kern.geom.virstor.debug", &g_virstor_debug);
  84 SYSCTL_UINT(_kern_geom_virstor, OID_AUTO, debug, CTLFLAG_RW, &g_virstor_debug,
  85     0, "Debug level (2=production, 5=normal, 15=excessive)");
  86
  87 static u_int g_virstor_chunk_watermark = 100;
  88 TUNABLE_INT("kern.geom.virstor.chunk_watermark", &g_virstor_chunk_watermark);
  89 SYSCTL_UINT(_kern_geom_virstor, OID_AUTO, chunk_watermark, CTLFLAG_RW,
  90     &g_virstor_chunk_watermark, 0,
  91     "Minimum number of free chunks before issuing administrative warning");
  92
  93 static u_int g_virstor_component_watermark = 1;
  94 TUNABLE_INT("kern.geom.virstor.component_watermark",
  95     &g_virstor_component_watermark);
  96 SYSCTL_UINT(_kern_geom_virstor, OID_AUTO, component_watermark, CTLFLAG_RW,
  97     &g_virstor_component_watermark, 0,
  98     "Minimum number of free components before issuing administrative warning");
  99
 100 static int read_metadata(struct g_consumer *, struct g_virstor_metadata *);
 101 static int write_metadata(struct g_consumer *, struct g_virstor_metadata *);
 102 static int clear_metadata(struct g_virstor_component *);
 103 static int add_provider_to_geom(struct g_virstor_softc *, struct g_provider *,
 104     struct g_virstor_metadata *);
 105 static struct g_geom *create_virstor_geom(struct g_class *,
 106     struct g_virstor_metadata *);
 107 static void virstor_check_and_run(struct g_virstor_softc *);
 108 static u_int virstor_valid_components(struct g_virstor_softc *);
 109 static int virstor_geom_destroy(struct g_virstor_softc *, boolean_t,
 110     boolean_t);
 111 static void remove_component(struct g_virstor_softc *,
 112     struct g_virstor_component *, boolean_t);
 113 static void bioq_dismantle(struct bio_queue_head *);
 114 static int allocate_chunk(struct g_virstor_softc *,
 115     struct g_virstor_component **, u_int *, u_int *);
 116 static void delay_destroy_consumer(void *, int);
 117 static void dump_component(struct g_virstor_component *comp);
 118 #if 0
 119 static void dump_me(struct virstor_map_entry *me, unsigned int nr);
 120 #endif
 121
 122 static void virstor_ctl_stop(struct gctl_req *, struct g_class *);
 123 static void virstor_ctl_add(struct gctl_req *, struct g_class *);
 124 static void virstor_ctl_remove(struct gctl_req *, struct g_class *);
 125 static struct g_virstor_softc * virstor_find_geom(const struct g_class *,
 126     const char *);
 127 static void update_metadata(struct g_virstor_softc *);
 128 static void fill_metadata(struct g_virstor_softc *, struct g_virstor_metadata *,
 129     u_int, u_int);
 130
 131 static void g_virstor_orphan(struct g_consumer *);
 132 static int g_virstor_access(struct g_provider *, int, int, int);
 133 static void g_virstor_start(struct bio *);
 134 static void g_virstor_dumpconf(struct sbuf *, const char *, struct g_geom *,
 135     struct g_consumer *, struct g_provider *);
 136 static void g_virstor_done(struct bio *);
 137
 138 static void invalid_call(void);
 139 /*
 140  * Initialise GEOM class (per-class callback)
 141  */
 142 static void
 143 g_virstor_init(struct g_class *mp __unused)
 144 {
 145
 146         /* Catch map struct size mismatch at compile time; Map entries must
 147          * fit into MAXPHYS exactly, with no wasted space. */
 148         CTASSERT(VIRSTOR_MAP_BLOCK_ENTRIES*VIRSTOR_MAP_ENTRY_SIZE == MAXPHYS);
 149
 150         /* Init UMA zones, TAILQ's, other global vars */
 151 }
 152
 153 /*
 154  * Finalise GEOM class (per-class callback)
 155  */
 156 static void
 157 g_virstor_fini(struct g_class *mp __unused)
 158 {
 159
 160         /* Deinit UMA zones & global vars */
 161 }
 162
 163 /*
 164  * Config (per-class callback)
 165  */
 166 static void
 167 g_virstor_config(struct gctl_req *req, struct g_class *cp, char const *verb)
 168 {
 169         uint32_t *version;
 170
 171         g_topology_assert();
 172
 173         version = gctl_get_paraml(req, "version", sizeof(*version));
 174         if (version == NULL) {
 175                 gctl_error(req, "Failed to get 'version' argument");
 176                 return;
 177         }
 178         if (*version != G_VIRSTOR_VERSION) {
 179                 gctl_error(req, "Userland and kernel versions out of sync");
 180                 return;
 181         }
 182
 183         g_topology_unlock();
 184         if (strcmp(verb, "add") == 0)
 185                 virstor_ctl_add(req, cp);
 186         else if (strcmp(verb, "stop") == 0 || strcmp(verb, "destroy") == 0)
 187                 virstor_ctl_stop(req, cp);
 188         else if (strcmp(verb, "remove") == 0)
 189                 virstor_ctl_remove(req, cp);
 190         else
 191                 gctl_error(req, "unknown verb: '%s'", verb);
 192         g_topology_lock();
 193 }
 194
 195 /*
 196  * "stop" verb from userland
 197  */
 198 static void
 199 virstor_ctl_stop(struct gctl_req *req, struct g_class *cp)
 200 {
 201         int *force, *nargs;
 202         int i;
 203
 204         nargs = gctl_get_paraml(req, "nargs", sizeof *nargs);
 205         if (nargs == NULL) {
 206                 gctl_error(req, "Error fetching argument '%s'", "nargs");
 207                 return;
 208         }
 209         if (*nargs < 1) {
 210                 gctl_error(req, "Invalid number of arguments");
 211                 return;
 212         }
 213         force = gctl_get_paraml(req, "force", sizeof *force);
 214         if (force == NULL) {
 215                 gctl_error(req, "Error fetching argument '%s'", "force");
 216                 return;
 217         }
 218
 219         g_topology_lock();
 220         for (i = 0; i < *nargs; i++) {
 221                 char param[8];
 222                 const char *name;
 223                 struct g_virstor_softc *sc;
 224                 int error;
 225
 226                 sprintf(param, "arg%d", i);
 227                 name = gctl_get_asciiparam(req, param);
 228                 if (name == NULL) {
 229                         gctl_error(req, "No 'arg%d' argument", i);
 230                         g_topology_unlock();
 231                         return;
 232                 }
 233                 sc = virstor_find_geom(cp, name);
 234                 LOG_MSG(LVL_INFO, "Stopping %s by the userland command",
 235                     sc->geom->name);
 236                 update_metadata(sc);
 237                 if ((error = virstor_geom_destroy(sc, TRUE, TRUE)) != 0) {
 238                         LOG_MSG(LVL_ERROR, "Cannot destroy %s: %d",
 239                             sc->geom->name, error);
 240                 }
 241         }
 242         g_topology_unlock();
 243 }
 244
 245 /*
 246  * "add" verb from userland - add new component(s) to the structure.
 247  * This will be done all at once in here, without going through the
 248  * .taste function for new components.
 249  */
 250 static void
 251 virstor_ctl_add(struct gctl_req *req, struct g_class *cp)
 252 {
 253         /* Note: while this is going on, I/O is being done on
 254          * the g_up and g_down threads. The idea is to make changes
 255          * to softc members in a way that can atomically activate
 256          * them all at once. */
 257         struct g_virstor_softc *sc;
 258         int *hardcode, *nargs;
 259         const char *geom_name;  /* geom to add a component to */
 260         struct g_consumer *fcp;
 261         struct g_virstor_bio_q *bq;
 262         u_int added;
 263         int error;
 264         int i;
 265
 266         nargs = gctl_get_paraml(req, "nargs", sizeof(*nargs));
 267         if (nargs == NULL) {
 268                 gctl_error(req, "Error fetching argument '%s'", "nargs");
 269                 return;
 270         }
 271         if (*nargs < 2) {
 272                 gctl_error(req, "Invalid number of arguments");
 273                 return;
 274         }
 275         hardcode = gctl_get_paraml(req, "hardcode", sizeof(*hardcode));
 276         if (hardcode == NULL) {
 277                 gctl_error(req, "Error fetching argument '%s'", "hardcode");
 278                 return;
 279         }
 280
 281         /* Find "our" geom */
 282         geom_name = gctl_get_asciiparam(req, "arg0");
 283         if (geom_name == NULL) {
 284                 gctl_error(req, "Error fetching argument '%s'", "geom_name (arg0)");
 285                 return;
 286         }
 287         sc = virstor_find_geom(cp, geom_name);
 288         if (sc == NULL) {
 289                 gctl_error(req, "Don't know anything about '%s'", geom_name);
 290                 return;
 291         }
 292
 293         if (virstor_valid_components(sc) != sc->n_components) {
 294                 LOG_MSG(LVL_ERROR, "Cannot add components to incomplete "
 295                     "virstor %s", sc->geom->name);
 296                 gctl_error(req, "Virstor %s is incomplete", sc->geom->name);
 297                 return;
 298         }
 299
 300         fcp = sc->components[0].gcons;
 301         added = 0;
 302         g_topology_lock();
 303         for (i = 1; i < *nargs; i++) {
 304                 struct g_virstor_metadata md;
 305                 char aname[8];
 306                 const char *prov_name;
 307                 struct g_provider *pp;
 308                 struct g_consumer *cp;
 309                 u_int nc;
 310                 u_int j;
 311
 312                 snprintf(aname, sizeof aname, "arg%d", i);
 313                 prov_name = gctl_get_asciiparam(req, aname);
 314                 if (strncmp(prov_name, _PATH_DEV, strlen(_PATH_DEV)) == 0)
 315                         prov_name += strlen(_PATH_DEV);
 316
 317                 pp = g_provider_by_name(prov_name);
 318                 if (pp == NULL) {
 319                         /* This is the most common error so be verbose about it */
 320                         if (added != 0) {
 321                                 gctl_error(req, "Invalid provider: '%s' (added"
 322                                     " %u components)", prov_name, added);
 323                                 update_metadata(sc);
 324                         } else {
 325                                 gctl_error(req, "Invalid provider: '%s'",
 326                                     prov_name);
 327                         }
 328                         g_topology_unlock();
 329                         return;
 330                 }
 331                 cp = g_new_consumer(sc->geom);
 332                 if (cp == NULL) {
 333                         gctl_error(req, "Cannot create consumer");
 334                         g_topology_unlock();
 335                         return;
 336                 }
 337                 error = g_attach(cp, pp);
 338                 if (error != 0) {
 339                         gctl_error(req, "Cannot attach a consumer to %s",
 340                             pp->name);
 341                         g_destroy_consumer(cp);
 342                         g_topology_unlock();
 343                         return;
 344                 }
 345                 if (fcp->acr != 0 || fcp->acw != 0 || fcp->ace != 0) {
 346                         error = g_access(cp, fcp->acr, fcp->acw, fcp->ace);
 347                         if (error != 0) {
 348                                 gctl_error(req, "Access request failed for %s",
 349                                     pp->name);
 350                                 g_destroy_consumer(cp);
 351                                 g_topology_unlock();
 352                                 return;
 353                         }
 354                 }
 355                 if (fcp->provider->sectorsize != pp->sectorsize) {
 356                         gctl_error(req, "Sector size doesn't fit for %s",
 357                             pp->name);
 358                         g_destroy_consumer(cp);
 359                         g_topology_unlock();
 360                         return;
 361                 }
 362                 for (j = 0; j < sc->n_components; j++) {
 363                         if (strcmp(sc->components[j].gcons->provider->name,
 364                             pp->name) == 0) {
 365                                 gctl_error(req, "Component %s already in %s",
 366                                     pp->name, sc->geom->name);
 367                                 g_destroy_consumer(cp);
 368                                 g_topology_unlock();
 369                                 return;
 370                         }
 371                 }
 372                 sc->components = realloc(sc->components,
 373                     sizeof(*sc->components) * (sc->n_components + 1),
 374                     M_GVIRSTOR, M_WAITOK);
 375
 376                 nc = sc->n_components;
 377                 sc->components[nc].gcons = cp;
 378                 sc->components[nc].sc = sc;
 379                 sc->components[nc].index = nc;
 380                 sc->components[nc].chunk_count = cp->provider->mediasize /
 381                     sc->chunk_size;
 382                 sc->components[nc].chunk_next = 0;
 383                 sc->components[nc].chunk_reserved = 0;
 384
 385                 if (sc->components[nc].chunk_count < 4) {
 386                         gctl_error(req, "Provider too small: %s",
 387                             cp->provider->name);
 388                         g_destroy_consumer(cp);
 389                         g_topology_unlock();
 390                         return;
 391                 }
 392                 fill_metadata(sc, &md, nc, *hardcode);
 393                 write_metadata(cp, &md);
 394                 /* The new component becomes visible when n_components is
 395                  * incremented */
 396                 sc->n_components++;
 397                 added++;
 398
 399         }
 400         /* This call to update_metadata() is critical. In case there's a
 401          * power failure in the middle of it and some components are updated
 402          * while others are not, there will be trouble on next .taste() iff
 403          * a non-updated component is detected first */
 404         update_metadata(sc);
 405         g_topology_unlock();
 406         LOG_MSG(LVL_INFO, "Added %d component(s) to %s", added,
 407             sc->geom->name);
 408         /* Fire off BIOs previously queued because there wasn't any
 409          * physical space left. If the BIOs still can't be satisfied
 410          * they will again be added to the end of the queue (during
 411          * which the mutex will be recursed) */
 412         bq = malloc(sizeof(*bq), M_GVIRSTOR, M_WAITOK);
 413         bq->bio = NULL;
 414         mtx_lock(&sc->delayed_bio_q_mtx);
 415         /* First, insert a sentinel to the queue end, so we don't
 416          * end up in an infinite loop if there's still no free
 417          * space available. */
 418         STAILQ_INSERT_TAIL(&sc->delayed_bio_q, bq, linkage);
 419         while (!STAILQ_EMPTY(&sc->delayed_bio_q)) {
 420                 bq = STAILQ_FIRST(&sc->delayed_bio_q);
 421                 if (bq->bio != NULL) {
 422                         g_virstor_start(bq->bio);
 423                         STAILQ_REMOVE_HEAD(&sc->delayed_bio_q, linkage);
 424                         free(bq, M_GVIRSTOR);
 425                 } else {
 426                         STAILQ_REMOVE_HEAD(&sc->delayed_bio_q, linkage);
 427                         free(bq, M_GVIRSTOR);
 428                         break;
 429                 }
 430         }
 431         mtx_unlock(&sc->delayed_bio_q_mtx);
 432
 433 }
 434
 435 /*
 436  * Find a geom handled by the class
 437  */
 438 static struct g_virstor_softc *
 439 virstor_find_geom(const struct g_class *cp, const char *name)
 440 {
 441         struct g_geom *gp;
 442
 443         LIST_FOREACH(gp, &cp->geom, geom) {
 444                 if (strcmp(name, gp->name) == 0)
 445                         return (gp->softc);
 446         }
 447         return (NULL);
 448 }
 449
 450 /*
 451  * Update metadata on all components to reflect the current state
 452  * of these fields:
 453  *    - chunk_next
 454  *    - flags
 455  *    - md_count
 456  * Expects things to be set up so write_metadata() can work, i.e.
 457  * the topology lock must be held.
 458  */
 459 static void
 460 update_metadata(struct g_virstor_softc *sc)
 461 {
 462         struct g_virstor_metadata md;
 463         int n;
 464
 465         if (virstor_valid_components(sc) != sc->n_components)
 466                 return; /* Incomplete device */
 467         LOG_MSG(LVL_DEBUG, "Updating metadata on components for %s",
 468             sc->geom->name);
 469         /* Update metadata on components */
 470         g_trace(G_T_TOPOLOGY, "%s(%s, %s)", __func__,
 471             sc->geom->class->name, sc->geom->name);
 472         g_topology_assert();
 473         for (n = 0; n < sc->n_components; n++) {
 474                 read_metadata(sc->components[n].gcons, &md);
 475                 md.chunk_next = sc->components[n].chunk_next;
 476                 md.flags = sc->components[n].flags;
 477                 md.md_count = sc->n_components;
 478                 write_metadata(sc->components[n].gcons, &md);
 479         }
 480 }
 481
 482 /*
 483  * Fills metadata (struct md) from information stored in softc and the nc'th
 484  * component of virstor
 485  */
 486 static void
 487 fill_metadata(struct g_virstor_softc *sc, struct g_virstor_metadata *md,
 488     u_int nc, u_int hardcode)
 489 {
 490         struct g_virstor_component *c;
 491
 492         bzero(md, sizeof *md);
 493         c = &sc->components[nc];
 494
 495         strncpy(md->md_magic, G_VIRSTOR_MAGIC, sizeof md->md_magic);
 496         md->md_version = G_VIRSTOR_VERSION;
 497         strncpy(md->md_name, sc->geom->name, sizeof md->md_name);
 498         md->md_id = sc->id;
 499         md->md_virsize = sc->virsize;
 500         md->md_chunk_size = sc->chunk_size;
 501         md->md_count = sc->n_components;
 502
 503         if (hardcode) {
 504                 strncpy(md->provider, c->gcons->provider->name,
 505                     sizeof md->provider);
 506         }
 507         md->no = nc;
 508         md->provsize = c->gcons->provider->mediasize;
 509         md->chunk_count = c->chunk_count;
 510         md->chunk_next = c->chunk_next;
 511         md->chunk_reserved = c->chunk_reserved;
 512         md->flags = c->flags;
 513 }
 514
 515 /*
 516  * Remove a component from virstor device.
 517  * Can only be done if the component is unallocated.
 518  */
 519 static void
 520 virstor_ctl_remove(struct gctl_req *req, struct g_class *cp)
 521 {
 522         /* As this is executed in parallel to I/O, operations on virstor
 523          * structures must be as atomic as possible. */
 524         struct g_virstor_softc *sc;
 525         int *nargs;
 526         const char *geom_name;
 527         u_int removed;
 528         int i;
 529
 530         nargs = gctl_get_paraml(req, "nargs", sizeof(*nargs));
 531         if (nargs == NULL) {
 532                 gctl_error(req, "Error fetching argument '%s'", "nargs");
 533                 return;
 534         }
 535         if (*nargs < 2) {
 536                 gctl_error(req, "Invalid number of arguments");
 537                 return;
 538         }
 539         /* Find "our" geom */
 540         geom_name = gctl_get_asciiparam(req, "arg0");
 541         if (geom_name == NULL) {
 542                 gctl_error(req, "Error fetching argument '%s'",
 543                     "geom_name (arg0)");
 544                 return;
 545         }
 546         sc = virstor_find_geom(cp, geom_name);
 547         if (sc == NULL) {
 548                 gctl_error(req, "Don't know anything about '%s'", geom_name);
 549                 return;
 550         }
 551
 552         if (virstor_valid_components(sc) != sc->n_components) {
 553                 LOG_MSG(LVL_ERROR, "Cannot remove components from incomplete "
 554                     "virstor %s", sc->geom->name);
 555                 gctl_error(req, "Virstor %s is incomplete", sc->geom->name);
 556                 return;
 557         }
 558
 559         removed = 0;
 560         for (i = 1; i < *nargs; i++) {
 561                 char param[8];
 562                 const char *prov_name;
 563                 int j, found;
 564                 struct g_virstor_component *newcomp, *compbak;
 565
 566                 sprintf(param, "arg%d", i);
 567                 prov_name = gctl_get_asciiparam(req, param);
 568                 if (strncmp(prov_name, _PATH_DEV, strlen(_PATH_DEV)) == 0)
 569                         prov_name += strlen(_PATH_DEV);
 570
 571                 found = -1;
 572                 for (j = 0; j < sc->n_components; j++) {
 573                         if (strcmp(sc->components[j].gcons->provider->name,
 574                             prov_name) == 0) {
 575                                 found = j;
 576                                 break;
 577                         }
 578                 }
 579                 if (found == -1) {
 580                         LOG_MSG(LVL_ERROR, "No %s component in %s",
 581                             prov_name, sc->geom->name);
 582                         continue;
 583                 }
 584
 585                 compbak = sc->components;
 586                 newcomp = malloc(sc->n_components * sizeof(*sc->components),
 587                     M_GVIRSTOR, M_WAITOK | M_ZERO);
 588                 bcopy(sc->components, newcomp, found * sizeof(*sc->components));
 589                 bcopy(&sc->components[found + 1], newcomp + found,
 590                     found * sizeof(*sc->components));
 591                 if ((sc->components[j].flags & VIRSTOR_PROVIDER_ALLOCATED) != 0) {
 592                         LOG_MSG(LVL_ERROR, "Allocated provider %s cannot be "
 593                             "removed from %s",
 594                             prov_name, sc->geom->name);
 595                         free(newcomp, M_GVIRSTOR);
 596                         /* We'll consider this non-fatal error */
 597                         continue;
 598                 }
 599                 /* Renumerate unallocated components */
 600                 for (j = 0; j < sc->n_components-1; j++) {
 601                         if ((sc->components[j].flags &
 602                             VIRSTOR_PROVIDER_ALLOCATED) == 0) {
 603                                 sc->components[j].index = j;
 604                         }
 605                 }
 606                 /* This is the critical section. If a component allocation
 607                  * event happens while both variables are not yet set,
 608                  * there will be trouble. Something will panic on encountering
 609                  * NULL sc->components[x].gcomp member.
 610                  * Luckily, component allocation happens very rarely and
 611                  * removing components is an abnormal action in any case. */
 612                 sc->components = newcomp;
 613                 sc->n_components--;
 614                 /* End critical section */
 615
 616                 g_topology_lock();
 617                 if (clear_metadata(&compbak[found]) != 0) {
 618                         LOG_MSG(LVL_WARNING, "Trouble ahead: cannot clear "
 619                             "metadata on %s", prov_name);
 620                 }
 621                 g_detach(compbak[found].gcons);
 622                 g_destroy_consumer(compbak[found].gcons);
 623                 g_topology_unlock();
 624
 625                 free(compbak, M_GVIRSTOR);
 626
 627                 removed++;
 628         }
 629
 630         /* This call to update_metadata() is critical. In case there's a
 631          * power failure in the middle of it and some components are updated
 632          * while others are not, there will be trouble on next .taste() iff
 633          * a non-updated component is detected first */
 634         g_topology_lock();
 635         update_metadata(sc);
 636         g_topology_unlock();
 637         LOG_MSG(LVL_INFO, "Removed %d component(s) from %s", removed,
 638             sc->geom->name);
 639 }
 640
 641 /*
 642  * Clear metadata sector on component
 643  */
 644 static int
 645 clear_metadata(struct g_virstor_component *comp)
 646 {
 647         char *buf;
 648         int error;
 649
 650         LOG_MSG(LVL_INFO, "Clearing metadata on %s",
 651             comp->gcons->provider->name);
 652         g_topology_assert();
 653         error = g_access(comp->gcons, 0, 1, 0);
 654         if (error != 0)
 655                 return (error);
 656         buf = malloc(comp->gcons->provider->sectorsize, M_GVIRSTOR,
 657             M_WAITOK | M_ZERO);
 658         error = g_write_data(comp->gcons,
 659             comp->gcons->provider->mediasize -
 660             comp->gcons->provider->sectorsize,
 661             buf,
 662             comp->gcons->provider->sectorsize);
 663         free(buf, M_GVIRSTOR);
 664         g_access(comp->gcons, 0, -1, 0);
 665         return (error);
 666 }
 667
 668 /*
 669  * Destroy geom forcibly.
 670  */
 671 static int
 672 g_virstor_destroy_geom(struct gctl_req *req __unused, struct g_class *mp,
 673     struct g_geom *gp)
 674 {
 675         struct g_virstor_softc *sc;
 676         int exitval;
 677
 678         sc = gp->softc;
 679         KASSERT(sc != NULL, ("%s: NULL sc", __func__));
 680
 681         exitval = 0;
 682         LOG_MSG(LVL_DEBUG, "%s called for %s, sc=%p", __func__, gp->name,
 683             gp->softc);
 684
 685         if (sc != NULL) {
 686 #ifdef INVARIANTS
 687                 char *buf;
 688                 int error;
 689                 off_t off;
 690                 int isclean, count;
 691                 int n;
 692
 693                 LOG_MSG(LVL_INFO, "INVARIANTS detected");
 694                 LOG_MSG(LVL_INFO, "Verifying allocation "
 695                     "table for %s", sc->geom->name);
 696                 count = 0;
 697                 for (n = 0; n < sc->chunk_count; n++) {
 698                         if (sc->map[n].flags || VIRSTOR_MAP_ALLOCATED != 0)
 699                                 count++;
 700                 }
 701                 LOG_MSG(LVL_INFO, "Device %s has %d allocated chunks",
 702                     sc->geom->name, count);
 703                 n = off = count = 0;
 704                 isclean = 1;
 705                 if (virstor_valid_components(sc) != sc->n_components) {
 706                         /* This is a incomplete virstor device (not all
 707                          * components have been found) */
 708                         LOG_MSG(LVL_ERROR, "Device %s is incomplete",
 709                             sc->geom->name);
 710                         goto bailout;
 711                 }
 712                 error = g_access(sc->components[0].gcons, 1, 0, 0);
 713                 KASSERT(error == 0, ("%s: g_access failed (%d)", __func__,
 714                     error));
 715                 /* Compare the whole on-disk allocation table with what's
 716                  * currently in memory */
 717                 while (n < sc->chunk_count) {
 718                         buf = g_read_data(sc->components[0].gcons, off,
 719                             sc->sectorsize, &error);
 720                         KASSERT(buf != NULL, ("g_read_data returned NULL (%d) "
 721                             "for read at %jd", error, off));
 722                         if (bcmp(buf, &sc->map[n], sc->sectorsize) != 0) {
 723                                 LOG_MSG(LVL_ERROR, "ERROR in allocation table, "
 724                                     "entry %d, offset %jd", n, off);
 725                                 isclean = 0;
 726                                 count++;
 727                         }
 728                         n += sc->me_per_sector;
 729                         off += sc->sectorsize;
 730                         g_free(buf);
 731                 }
 732                 error = g_access(sc->components[0].gcons, -1, 0, 0);
 733                 KASSERT(error == 0, ("%s: g_access failed (%d) on exit",
 734                     __func__, error));
 735                 if (isclean != 1) {
 736                         LOG_MSG(LVL_ERROR, "ALLOCATION TABLE CORRUPTED FOR %s "
 737                             "(%d sectors don't match, max %zu allocations)",
 738                             sc->geom->name, count,
 739                             count * sc->me_per_sector);
 740                 } else {
 741                         LOG_MSG(LVL_INFO, "Allocation table ok for %s",
 742                             sc->geom->name);
 743                 }
 744 bailout:
 745 #endif
 746                 update_metadata(sc);
 747                 virstor_geom_destroy(sc, FALSE, FALSE);
 748                 exitval = EAGAIN;
 749         } else
 750                 exitval = 0;
 751         return (exitval);
 752 }
 753
 754 /*
 755  * Taste event (per-class callback)
 756  * Examines a provider and creates geom instances if needed
 757  */
 758 static struct g_geom *
 759 g_virstor_taste(struct g_class *mp, struct g_provider *pp, int flags)
 760 {
 761         struct g_virstor_metadata md;
 762         struct g_geom *gp;
 763         struct g_consumer *cp;
 764         struct g_virstor_softc *sc;
 765         int error;
 766
 767         g_trace(G_T_TOPOLOGY, "%s(%s, %s)", __func__, mp->name, pp->name);
 768         g_topology_assert();
 769         LOG_MSG(LVL_DEBUG, "Tasting %s", pp->name);
 770
 771         /* We need a dummy geom to attach a consumer to the given provider */
 772         gp = g_new_geomf(mp, "virstor:taste.helper");
 773         gp->start = (void *)invalid_call;       /* XXX: hacked up so the        */
 774         gp->access = (void *)invalid_call;      /* compiler doesn't complain.   */
 775         gp->orphan = (void *)invalid_call;      /* I really want these to fail. */
 776
 777         cp = g_new_consumer(gp);
 778         g_attach(cp, pp);
 779         error = read_metadata(cp, &md);
 780         g_detach(cp);
 781         g_destroy_consumer(cp);
 782         g_destroy_geom(gp);
 783
 784         if (error != 0)
 785                 return (NULL);
 786
 787         if (strcmp(md.md_magic, G_VIRSTOR_MAGIC) != 0)
 788                 return (NULL);
 789         if (md.md_version != G_VIRSTOR_VERSION) {
 790                 LOG_MSG(LVL_ERROR, "Kernel module version invalid "
 791                     "to handle %s (%s) : %d should be %d",
 792                     md.md_name, pp->name, md.md_version, G_VIRSTOR_VERSION);
 793                 return (NULL);
 794         }
 795         if (md.provsize != pp->mediasize)
 796                 return (NULL);
 797
 798         /* If the provider name is hardcoded, use the offered provider only
 799          * if it's been offered with its proper name (the one used in
 800          * the label command). */
 801         if (md.provider[0] != '\0') {
 802                 if (strcmp(md.provider, pp->name) != 0)
 803                         return (NULL);
 804         }
 805
 806         /* Iterate all geoms this class already knows about to see if a new
 807          * geom instance of this class needs to be created (in case the provider
 808          * is first from a (possibly) multi-consumer geom) or it just needs
 809          * to be added to an existing instance. */
 810         sc = NULL;
 811         gp = NULL;
 812         LIST_FOREACH(gp, &mp->geom, geom) {
 813                 sc = gp->softc;
 814                 if (sc == NULL)
 815                         continue;
 816                 if (strcmp(md.md_name, sc->geom->name) != 0)
 817                         continue;
 818                 if (md.md_id != sc->id)
 819                         continue;
 820                 break;
 821         }
 822         if (gp != NULL) { /* We found an existing geom instance; add to it */
 823                 LOG_MSG(LVL_INFO, "Adding %s to %s", pp->name, md.md_name);
 824                 error = add_provider_to_geom(sc, pp, &md);
 825                 if (error != 0) {
 826                         LOG_MSG(LVL_ERROR, "Error adding %s to %s (error %d)",
 827                             pp->name, md.md_name, error);
 828                         return (NULL);
 829                 }
 830         } else { /* New geom instance needs to be created */
 831                 gp = create_virstor_geom(mp, &md);
 832                 if (gp == NULL) {
 833                         LOG_MSG(LVL_ERROR, "Error creating new instance of "
 834                             "class %s: %s", mp->name, md.md_name);
 835                         LOG_MSG(LVL_DEBUG, "Error creating %s at %s",
 836                             md.md_name, pp->name);
 837                         return (NULL);
 838                 }
 839                 sc = gp->softc;
 840                 LOG_MSG(LVL_INFO, "Adding %s to %s (first found)", pp->name,
 841                     md.md_name);
 842                 error = add_provider_to_geom(sc, pp, &md);
 843                 if (error != 0) {
 844                         LOG_MSG(LVL_ERROR, "Error adding %s to %s (error %d)",
 845                             pp->name, md.md_name, error);
 846                         virstor_geom_destroy(sc, TRUE, FALSE);
 847                         return (NULL);
 848                 }
 849         }
 850
 851         return (gp);
 852 }
 853
 854 /*
 855  * Destroyes consumer passed to it in arguments. Used as a callback
 856  * on g_event queue.
 857  */
 858 static void
 859 delay_destroy_consumer(void *arg, int flags __unused)
 860 {
 861         struct g_consumer *c = arg;
 862         KASSERT(c != NULL, ("%s: invalid consumer", __func__));
 863         LOG_MSG(LVL_DEBUG, "Consumer %s destroyed with delay",
 864             c->provider->name);
 865         g_detach(c);
 866         g_destroy_consumer(c);
 867 }
 868
 869 /*
 870  * Remove a component (consumer) from geom instance; If it's the first
 871  * component being removed, orphan the provider to announce geom's being
 872  * dismantled
 873  */
 874 static void
 875 remove_component(struct g_virstor_softc *sc, struct g_virstor_component *comp,
 876     boolean_t delay)
 877 {
 878         struct g_consumer *c;
 879
 880         KASSERT(comp->gcons != NULL, ("Component with no consumer in %s",
 881             sc->geom->name));
 882         c = comp->gcons;
 883
 884         comp->gcons = NULL;
 885         KASSERT(c->provider != NULL, ("%s: no provider", __func__));
 886         LOG_MSG(LVL_DEBUG, "Component %s removed from %s", c->provider->name,
 887             sc->geom->name);
 888         if (sc->provider != NULL) {
 889                 /* Whither, GEOM? */
 890                 sc->provider->flags |= G_PF_WITHER;
 891                 g_orphan_provider(sc->provider, ENXIO);
 892                 sc->provider = NULL;
 893                 LOG_MSG(LVL_INFO, "Removing provider %s", sc->geom->name);
 894         }
 895
 896         if (c->acr > 0 || c->acw > 0 || c->ace > 0)
 897                 g_access(c, -c->acr, -c->acw, -c->ace);
 898         if (delay) {
 899                 /* Destroy consumer after it's tasted */
 900                 g_post_event(delay_destroy_consumer, c, M_WAITOK, NULL);
 901         } else {
 902                 g_detach(c);
 903                 g_destroy_consumer(c);
 904         }
 905 }
 906
 907 /*
 908  * Destroy geom - called internally
 909  * See g_virstor_destroy_geom for the other one
 910  */
 911 static int
 912 virstor_geom_destroy(struct g_virstor_softc *sc, boolean_t force,
 913     boolean_t delay)
 914 {
 915         struct g_provider *pp;
 916         struct g_geom *gp;
 917         int n;
 918
 919         g_topology_assert();
 920
 921         if (sc == NULL)
 922                 return (ENXIO);
 923
 924         pp = sc->provider;
 925         if (pp != NULL && (pp->acr != 0 || pp->acw != 0 || pp->ace != 0)) {
 926                 LOG_MSG(force ? LVL_WARNING : LVL_ERROR,
 927                     "Device %s is still open.", pp->name);
 928                 if (!force)
 929                         return (EBUSY);
 930         }
 931
 932         for (n = 0; n < sc->n_components; n++) {
 933                 if (sc->components[n].gcons != NULL)
 934                         remove_component(sc, &sc->components[n], delay);
 935         }
 936
 937         gp = sc->geom;
 938         gp->softc = NULL;
 939
 940         KASSERT(sc->provider == NULL, ("Provider still exists for %s",
 941             gp->name));
 942
 943         /* XXX: This might or might not work, since we're called with
 944          * the topology lock held. Also, it might panic the kernel if
 945          * the error'd BIO is in softupdates code. */
 946         mtx_lock(&sc->delayed_bio_q_mtx);
 947         while (!STAILQ_EMPTY(&sc->delayed_bio_q)) {
 948                 struct g_virstor_bio_q *bq;
 949                 bq = STAILQ_FIRST(&sc->delayed_bio_q);
 950                 bq->bio->bio_error = ENOSPC;
 951                 g_io_deliver(bq->bio, EIO);
 952                 STAILQ_REMOVE_HEAD(&sc->delayed_bio_q, linkage);
 953                 free(bq, M_GVIRSTOR);
 954         }
 955         mtx_unlock(&sc->delayed_bio_q_mtx);
 956         mtx_destroy(&sc->delayed_bio_q_mtx);
 957
 958         free(sc->map, M_GVIRSTOR);
 959         free(sc->components, M_GVIRSTOR);
 960         bzero(sc, sizeof *sc);
 961         free(sc, M_GVIRSTOR);
 962
 963         pp = LIST_FIRST(&gp->provider); /* We only offer one provider */
 964         if (pp == NULL || (pp->acr == 0 && pp->acw == 0 && pp->ace == 0))
 965                 LOG_MSG(LVL_DEBUG, "Device %s destroyed", gp->name);
 966
 967         g_wither_geom(gp, ENXIO);
 968
 969         return (0);
 970 }
 971
 972 /*
 973  * Utility function: read metadata & decode. Wants topology lock to be
 974  * held.
 975  */
 976 static int
 977 read_metadata(struct g_consumer *cp, struct g_virstor_metadata *md)
 978 {
 979         struct g_provider *pp;
 980         char *buf;
 981         int error;
 982
 983         g_topology_assert();
 984         error = g_access(cp, 1, 0, 0);
 985         if (error != 0)
 986                 return (error);
 987         pp = cp->provider;
 988         g_topology_unlock();
 989         buf = g_read_data(cp, pp->mediasize - pp->sectorsize, pp->sectorsize,
 990             &error);
 991         g_topology_lock();
 992         g_access(cp, -1, 0, 0);
 993         if (buf == NULL)
 994                 return (error);
 995
 996         virstor_metadata_decode(buf, md);
 997         g_free(buf);
 998
 999         return (0);
1000 }
1001
1002 /**
1003  * Utility function: encode & write metadata. Assumes topology lock is
1004  * held.
1005  */
1006 static int
1007 write_metadata(struct g_consumer *cp, struct g_virstor_metadata *md)
1008 {
1009         struct g_provider *pp;
1010         char *buf;
1011         int error;
1012
1013         KASSERT(cp != NULL && md != NULL && cp->provider != NULL,
1014             ("Something's fishy in %s", __func__));
1015         LOG_MSG(LVL_DEBUG, "Writing metadata on %s", cp->provider->name);
1016         g_topology_assert();
1017         error = g_access(cp, 0, 1, 0);
1018         if (error != 0)
1019                 return (error);
1020         pp = cp->provider;
1021
1022         buf = malloc(pp->sectorsize, M_GVIRSTOR, M_WAITOK);
1023         virstor_metadata_encode(md, buf);
1024         g_topology_unlock();
1025         error = g_write_data(cp, pp->mediasize - pp->sectorsize, buf,
1026             pp->sectorsize);
1027         g_topology_lock();
1028         g_access(cp, 0, -1, 0);
1029
1030         free(buf, M_GVIRSTOR);
1031         return (0);
1032 }
1033
1034 /*
1035  * Creates a new instance of this GEOM class, initialise softc
1036  */
1037 static struct g_geom *
1038 create_virstor_geom(struct g_class *mp, struct g_virstor_metadata *md)
1039 {
1040         struct g_geom *gp;
1041         struct g_virstor_softc *sc;
1042
1043         LOG_MSG(LVL_DEBUG, "Creating geom instance for %s (id=%u)",
1044             md->md_name, md->md_id);
1045
1046         if (md->md_count < 1 || md->md_chunk_size < 1 ||
1047             md->md_virsize < md->md_chunk_size) {
1048                 /* This is bogus configuration, and probably means data is
1049                  * somehow corrupted. Panic, maybe? */
1050                 LOG_MSG(LVL_ERROR, "Nonsensical metadata information for %s",
1051                     md->md_name);
1052                 return (NULL);
1053         }
1054
1055         /* Check if it's already created */
1056         LIST_FOREACH(gp, &mp->geom, geom) {
1057                 sc = gp->softc;
1058                 if (sc != NULL && strcmp(sc->geom->name, md->md_name) == 0) {
1059                         LOG_MSG(LVL_WARNING, "Geom %s already exists",
1060                             md->md_name);
1061                         if (sc->id != md->md_id) {
1062                                 LOG_MSG(LVL_ERROR,
1063                                     "Some stale or invalid components "
1064                                     "exist for virstor device named %s. "
1065                                     "You will need to <CLEAR> all stale "
1066                                     "components and maybe reconfigure "
1067                                     "the virstor device. Tune "
1068                                     "kern.geom.virstor.debug sysctl up "
1069                                     "for more information.",
1070                                     sc->geom->name);
1071                         }
1072                         return (NULL);
1073                 }
1074         }
1075         gp = g_new_geomf(mp, "%s", md->md_name);
1076         gp->softc = NULL; /* to circumevent races that test softc */
1077
1078         gp->start = g_virstor_start;
1079         gp->spoiled = g_virstor_orphan;
1080         gp->orphan = g_virstor_orphan;
1081         gp->access = g_virstor_access;
1082         gp->dumpconf = g_virstor_dumpconf;
1083
1084         sc = malloc(sizeof(*sc), M_GVIRSTOR, M_WAITOK | M_ZERO);
1085         sc->id = md->md_id;
1086         sc->n_components = md->md_count;
1087         sc->components = malloc(sizeof(struct g_virstor_component) * md->md_count,
1088             M_GVIRSTOR, M_WAITOK | M_ZERO);
1089         sc->chunk_size = md->md_chunk_size;
1090         sc->virsize = md->md_virsize;
1091         STAILQ_INIT(&sc->delayed_bio_q);
1092         mtx_init(&sc->delayed_bio_q_mtx, "gvirstor_delayed_bio_q_mtx",
1093             "gvirstor", MTX_DEF | MTX_RECURSE);
1094
1095         sc->geom = gp;
1096         sc->provider = NULL; /* virstor_check_and_run will create it */
1097         gp->softc = sc;
1098
1099         LOG_MSG(LVL_ANNOUNCE, "Device %s created", sc->geom->name);
1100
1101         return (gp);
1102 }
1103
1104 /*
1105  * Add provider to a GEOM class instance
1106  */
1107 static int
1108 add_provider_to_geom(struct g_virstor_softc *sc, struct g_provider *pp,
1109     struct g_virstor_metadata *md)
1110 {
1111         struct g_virstor_component *component;
1112         struct g_consumer *cp, *fcp;
1113         struct g_geom *gp;
1114         int error;
1115
1116         if (md->no >= sc->n_components)
1117                 return (EINVAL);
1118
1119         /* "Current" compontent */
1120         component = &(sc->components[md->no]);
1121         if (component->gcons != NULL)
1122                 return (EEXIST);
1123
1124         gp = sc->geom;
1125         fcp = LIST_FIRST(&gp->consumer);
1126
1127         cp = g_new_consumer(gp);
1128         error = g_attach(cp, pp);
1129
1130         if (error != 0) {
1131                 g_destroy_consumer(cp);
1132                 return (error);
1133         }
1134
1135         if (fcp != NULL) {
1136                 if (fcp->provider->sectorsize != pp->sectorsize) {
1137                         /* TODO: this can be made to work */
1138                         LOG_MSG(LVL_ERROR, "Provider %s of %s has invalid "
1139                             "sector size (%d)", pp->name, sc->geom->name,
1140                             pp->sectorsize);
1141                         return (EINVAL);
1142                 }
1143                 if (fcp->acr > 0 || fcp->acw || fcp->ace > 0) {
1144                         /* Replicate access permissions from first "live" consumer
1145                          * to the new one */
1146                         error = g_access(cp, fcp->acr, fcp->acw, fcp->ace);
1147                         if (error != 0) {
1148                                 g_detach(cp);
1149                                 g_destroy_consumer(cp);
1150                                 return (error);
1151                         }
1152                 }
1153         }
1154
1155         /* Bring up a new component */
1156         cp->private = component;
1157         component->gcons = cp;
1158         component->sc = sc;
1159         component->index = md->no;
1160         component->chunk_count = md->chunk_count;
1161         component->chunk_next = md->chunk_next;
1162         component->chunk_reserved = md->chunk_reserved;
1163         component->flags = md->flags;
1164
1165         LOG_MSG(LVL_DEBUG, "%s attached to %s", pp->name, sc->geom->name);
1166
1167         virstor_check_and_run(sc);
1168         return (0);
1169 }
1170
1171 /*
1172  * Check if everything's ready to create the geom provider & device entry,
1173  * create and start provider.
1174  * Called ultimately by .taste, from g_event thread
1175  */
1176 static void
1177 virstor_check_and_run(struct g_virstor_softc *sc)
1178 {
1179         off_t off;
1180         size_t n, count;
1181         int index;
1182         int error;
1183
1184         if (virstor_valid_components(sc) != sc->n_components)
1185                 return;
1186
1187         if (virstor_valid_components(sc) == 0) {
1188                 /* This is actually a candidate for panic() */
1189                 LOG_MSG(LVL_ERROR, "No valid components for %s?",
1190                     sc->provider->name);
1191                 return;
1192         }
1193
1194         sc->sectorsize = sc->components[0].gcons->provider->sectorsize;
1195
1196         /* Initialise allocation map from the first consumer */
1197         sc->chunk_count = sc->virsize / sc->chunk_size;
1198         if (sc->chunk_count * (off_t)sc->chunk_size != sc->virsize) {
1199                 LOG_MSG(LVL_WARNING, "Device %s truncated to %ju bytes",
1200                     sc->provider->name,
1201                     sc->chunk_count * (off_t)sc->chunk_size);
1202         }
1203         sc->map_size = sc->chunk_count * sizeof *(sc->map);
1204         /* The following allocation is in order of 4MB - 8MB */
1205         sc->map = malloc(sc->map_size, M_GVIRSTOR, M_WAITOK);
1206         KASSERT(sc->map != NULL, ("%s: Memory allocation error (%zu bytes) for %s",
1207             __func__, sc->map_size, sc->provider->name));
1208         sc->map_sectors = sc->map_size / sc->sectorsize;
1209
1210         count = 0;
1211         for (n = 0; n < sc->n_components; n++)
1212                 count += sc->components[n].chunk_count;
1213         LOG_MSG(LVL_INFO, "Device %s has %zu physical chunks and %zu virtual "
1214             "(%zu KB chunks)",
1215             sc->geom->name, count, sc->chunk_count, sc->chunk_size / 1024);
1216
1217         error = g_access(sc->components[0].gcons, 1, 0, 0);
1218         if (error != 0) {
1219                 LOG_MSG(LVL_ERROR, "Cannot acquire read access for %s to "
1220                     "read allocation map for %s",
1221                     sc->components[0].gcons->provider->name,
1222                     sc->geom->name);
1223                 return;
1224         }
1225         /* Read in the allocation map */
1226         LOG_MSG(LVL_DEBUG, "Reading map for %s from %s", sc->geom->name,
1227             sc->components[0].gcons->provider->name);
1228         off = count = n = 0;
1229         while (count < sc->map_size) {
1230                 struct g_virstor_map_entry *mapbuf;
1231                 size_t bs;
1232
1233                 bs = MIN(MAXPHYS, sc->map_size - count);
1234                 if (bs % sc->sectorsize != 0) {
1235                         /* Check for alignment errors */
1236                         bs = (bs / sc->sectorsize) * sc->sectorsize;
1237                         if (bs == 0)
1238                                 break;
1239                         LOG_MSG(LVL_ERROR, "Trouble: map is not sector-aligned "
1240                             "for %s on %s", sc->geom->name,
1241                             sc->components[0].gcons->provider->name);
1242                 }
1243                 mapbuf = g_read_data(sc->components[0].gcons, off, bs, &error);
1244                 if (mapbuf == NULL) {
1245                         free(sc->map, M_GVIRSTOR);
1246                         LOG_MSG(LVL_ERROR, "Error reading allocation map "
1247                             "for %s from %s (offset %ju) (error %d)",
1248                             sc->geom->name,
1249                             sc->components[0].gcons->provider->name,
1250                             off, error);
1251                         return;
1252                 }
1253
1254                 bcopy(mapbuf, &sc->map[n], bs);
1255                 off += bs;
1256                 count += bs;
1257                 n += bs / sizeof *(sc->map);
1258                 g_free(mapbuf);
1259         }
1260         g_access(sc->components[0].gcons, -1, 0, 0);
1261         LOG_MSG(LVL_DEBUG, "Read map for %s", sc->geom->name);
1262
1263         /* find first component with allocatable chunks */
1264         index = -1;
1265         for (n = 0; n < sc->n_components; n++) {
1266                 if (sc->components[n].chunk_next <
1267                     sc->components[n].chunk_count) {
1268                         index = n;
1269                         break;
1270                 }
1271         }
1272         if (index == -1)
1273                 /* not found? set it to the last component and handle it
1274                  * later */
1275                 index = sc->n_components - 1;
1276
1277         if (index >= sc->n_components - g_virstor_component_watermark - 1) {
1278                 LOG_MSG(LVL_WARNING, "Device %s running out of components "
1279                     "(%d/%u: %s)", sc->geom->name,
1280                     index+1,
1281                     sc->n_components,
1282                     sc->components[index].gcons->provider->name);
1283         }
1284         sc->curr_component = index;
1285
1286         if (sc->components[index].chunk_next >=
1287             sc->components[index].chunk_count - g_virstor_chunk_watermark) {
1288                 LOG_MSG(LVL_WARNING,
1289                     "Component %s of %s is running out of free space "
1290                     "(%u chunks left)",
1291                     sc->components[index].gcons->provider->name,
1292                     sc->geom->name, sc->components[index].chunk_count -
1293                     sc->components[index].chunk_next);
1294         }
1295
1296         sc->me_per_sector = sc->sectorsize / sizeof *(sc->map);
1297         if (sc->sectorsize % sizeof *(sc->map) != 0) {
1298                 LOG_MSG(LVL_ERROR,
1299                     "%s: Map entries don't fit exactly in a sector (%s)",
1300                     __func__, sc->geom->name);
1301                 return;
1302         }
1303
1304         /* Recalculate allocated chunks in components & at the same time
1305          * verify map data is sane. We could trust metadata on this, but
1306          * we want to make sure. */
1307         for (n = 0; n < sc->n_components; n++)
1308                 sc->components[n].chunk_next = sc->components[n].chunk_reserved;
1309
1310         for (n = 0; n < sc->chunk_count; n++) {
1311                 if (sc->map[n].provider_no >= sc->n_components ||
1312                         sc->map[n].provider_chunk >=
1313                         sc->components[sc->map[n].provider_no].chunk_count) {
1314                         LOG_MSG(LVL_ERROR, "%s: Invalid entry %u in map for %s",
1315                             __func__, (u_int)n, sc->geom->name);
1316                         LOG_MSG(LVL_ERROR, "%s: provider_no: %u, n_components: %u"
1317                             " provider_chunk: %u, chunk_count: %u", __func__,
1318                             sc->map[n].provider_no, sc->n_components,
1319                             sc->map[n].provider_chunk,
1320                             sc->components[sc->map[n].provider_no].chunk_count);
1321                         return;
1322                 }
1323                 if (sc->map[n].flags & VIRSTOR_MAP_ALLOCATED)
1324                         sc->components[sc->map[n].provider_no].chunk_next++;
1325         }
1326
1327         sc->provider = g_new_providerf(sc->geom, "virstor/%s",
1328             sc->geom->name);
1329
1330         sc->provider->sectorsize = sc->sectorsize;
1331         sc->provider->mediasize = sc->virsize;
1332         g_error_provider(sc->provider, 0);
1333
1334         LOG_MSG(LVL_INFO, "%s activated", sc->provider->name);
1335         LOG_MSG(LVL_DEBUG, "%s starting with current component %u, starting "
1336             "chunk %u", sc->provider->name, sc->curr_component,
1337             sc->components[sc->curr_component].chunk_next);
1338 }
1339
1340 /*
1341  * Returns count of active providers in this geom instance
1342  */
1343 static u_int
1344 virstor_valid_components(struct g_virstor_softc *sc)
1345 {
1346         unsigned int nc, i;
1347
1348         nc = 0;
1349         KASSERT(sc != NULL, ("%s: softc is NULL", __func__));
1350         KASSERT(sc->components != NULL, ("%s: sc->components is NULL", __func__));
1351         for (i = 0; i < sc->n_components; i++)
1352                 if (sc->components[i].gcons != NULL)
1353                         nc++;
1354         return (nc);
1355 }
1356
1357 /*
1358  * Called when the consumer gets orphaned (?)
1359  */
1360 static void
1361 g_virstor_orphan(struct g_consumer *cp)
1362 {
1363         struct g_virstor_softc *sc;
1364         struct g_virstor_component *comp;
1365         struct g_geom *gp;
1366
1367         g_topology_assert();
1368         gp = cp->geom;
1369         sc = gp->softc;
1370         if (sc == NULL)
1371                 return;
1372
1373         comp = cp->private;
1374         KASSERT(comp != NULL, ("%s: No component in private part of consumer",
1375             __func__));
1376         remove_component(sc, comp, FALSE);
1377         if (virstor_valid_components(sc) == 0)
1378                 virstor_geom_destroy(sc, TRUE, FALSE);
1379 }
1380
1381 /*
1382  * Called to notify geom when it's been opened, and for what intent
1383  */
1384 static int
1385 g_virstor_access(struct g_provider *pp, int dr, int dw, int de)
1386 {
1387         struct g_consumer *c;
1388         struct g_virstor_softc *sc;
1389         struct g_geom *gp;
1390         int error;
1391
1392         KASSERT(pp != NULL, ("%s: NULL provider", __func__));
1393         gp = pp->geom;
1394         KASSERT(gp != NULL, ("%s: NULL geom", __func__));
1395         sc = gp->softc;
1396
1397         if (sc == NULL) {
1398                 /* It seems that .access can be called with negative dr,dw,dx
1399                  * in this case but I want to check for myself */
1400                 LOG_MSG(LVL_WARNING, "access(%d, %d, %d) for %s",
1401                     dr, dw, de, pp->name);
1402                 /* This should only happen when geom is withered so
1403                  * allow only negative requests */
1404                 KASSERT(dr <= 0 && dw <= 0 && de <= 0,
1405                     ("%s: Positive access for %s", __func__, pp->name));
1406                 if (pp->acr + dr == 0 && pp->acw + dw == 0 && pp->ace + de == 0)
1407                         LOG_MSG(LVL_DEBUG, "Device %s definitely destroyed",
1408                             pp->name);
1409                 return (0);
1410         }
1411
1412         /* Grab an exclusive bit to propagate on our consumers on first open */
1413         if (pp->acr == 0 && pp->acw == 0 && pp->ace == 0)
1414                 de++;
1415         /* ... drop it on close */
1416         if (pp->acr + dr == 0 && pp->acw + dw == 0 && pp->ace + de == 0) {
1417                 de--;
1418                 update_metadata(sc);    /* Writes statistical information */
1419         }
1420
1421         error = ENXIO;
1422         LIST_FOREACH(c, &gp->consumer, consumer) {
1423                 KASSERT(c != NULL, ("%s: consumer is NULL", __func__));
1424                 error = g_access(c, dr, dw, de);
1425                 if (error != 0) {
1426                         struct g_consumer *c2;
1427
1428                         /* Backout earlier changes */
1429                         LIST_FOREACH(c2, &gp->consumer, consumer) {
1430                                 if (c2 == c) /* all eariler components fixed */
1431                                         return (error);
1432                                 g_access(c2, -dr, -dw, -de);
1433                         }
1434                 }
1435         }
1436
1437         return (error);
1438 }
1439
1440 /*
1441  * Generate XML dump of current state
1442  */
1443 static void
1444 g_virstor_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp,
1445     struct g_consumer *cp, struct g_provider *pp)
1446 {
1447         struct g_virstor_softc *sc;
1448
1449         g_topology_assert();
1450         sc = gp->softc;
1451
1452         if (sc == NULL || pp != NULL)
1453                 return;
1454
1455         if (cp != NULL) {
1456                 /* For each component */
1457                 struct g_virstor_component *comp;
1458
1459                 comp = cp->private;
1460                 if (comp == NULL)
1461                         return;
1462                 sbuf_printf(sb, "%s<ComponentIndex>%u</ComponentIndex>\n",
1463                     indent, comp->index);
1464                 sbuf_printf(sb, "%s<ChunkCount>%u</ChunkCount>\n",
1465                     indent, comp->chunk_count);
1466                 sbuf_printf(sb, "%s<ChunksUsed>%u</ChunksUsed>\n",
1467                     indent, comp->chunk_next);
1468                 sbuf_printf(sb, "%s<ChunksReserved>%u</ChunksReserved>\n",
1469                     indent, comp->chunk_reserved);
1470                 sbuf_printf(sb, "%s<StorageFree>%u%%</StorageFree>\n",
1471                     indent,
1472                     comp->chunk_next > 0 ? 100 -
1473                     ((comp->chunk_next + comp->chunk_reserved) * 100) /
1474                     comp->chunk_count : 100);
1475         } else {
1476                 /* For the whole thing */
1477                 u_int count, used, i;
1478                 off_t size;
1479
1480                 count = used = size = 0;
1481                 for (i = 0; i < sc->n_components; i++) {
1482                         if (sc->components[i].gcons != NULL) {
1483                                 count += sc->components[i].chunk_count;
1484                                 used += sc->components[i].chunk_next +
1485                                     sc->components[i].chunk_reserved;
1486                                 size += sc->components[i].gcons->
1487                                     provider->mediasize;
1488                         }
1489                 }
1490
1491                 sbuf_printf(sb, "%s<Status>"
1492                     "Components=%u, Online=%u</Status>\n", indent,
1493                     sc->n_components, virstor_valid_components(sc));
1494                 sbuf_printf(sb, "%s<State>%u%% physical free</State>\n",
1495                     indent, 100-(used * 100) / count);
1496                 sbuf_printf(sb, "%s<ChunkSize>%zu</ChunkSize>\n", indent,
1497                     sc->chunk_size);
1498                 sbuf_printf(sb, "%s<PhysicalFree>%u%%</PhysicalFree>\n",
1499                     indent, used > 0 ? 100 - (used * 100) / count : 100);
1500                 sbuf_printf(sb, "%s<ChunkPhysicalCount>%u</ChunkPhysicalCount>\n",
1501                     indent, count);
1502                 sbuf_printf(sb, "%s<ChunkVirtualCount>%zu</ChunkVirtualCount>\n",
1503                     indent, sc->chunk_count);
1504                 sbuf_printf(sb, "%s<PhysicalBacking>%zu%%</PhysicalBacking>\n",
1505                     indent,
1506                     (count * 100) / sc->chunk_count);
1507                 sbuf_printf(sb, "%s<PhysicalBackingSize>%jd</PhysicalBackingSize>\n",
1508                     indent, size);
1509                 sbuf_printf(sb, "%s<VirtualSize>%jd</VirtualSize>\n", indent,
1510                     sc->virsize);
1511         }
1512 }
1513
1514 /*
1515  * GEOM .done handler
1516  * Can't use standard handler because one requested IO may
1517  * fork into additional data IOs
1518  */
1519 static void
1520 g_virstor_done(struct bio *b)
1521 {
1522         struct g_virstor_softc *sc;
1523         struct bio *parent_b;
1524
1525         parent_b = b->bio_parent;
1526         sc = parent_b->bio_to->geom->softc;
1527
1528         if (b->bio_error != 0) {
1529                 LOG_MSG(LVL_ERROR, "Error %d for offset=%ju, length=%ju, %s",
1530                     b->bio_error, b->bio_offset, b->bio_length,
1531                     b->bio_to->name);
1532                 if (parent_b->bio_error == 0)
1533                         parent_b->bio_error = b->bio_error;
1534         }
1535
1536         parent_b->bio_inbed++;
1537         parent_b->bio_completed += b->bio_completed;
1538
1539         if (parent_b->bio_children == parent_b->bio_inbed) {
1540                 parent_b->bio_completed = parent_b->bio_length;
1541                 g_io_deliver(parent_b, parent_b->bio_error);
1542         }
1543         g_destroy_bio(b);
1544 }
1545
1546 /*
1547  * I/O starts here
1548  * Called in g_down thread
1549  */
1550 static void
1551 g_virstor_start(struct bio *b)
1552 {
1553         struct g_virstor_softc *sc;
1554         struct g_virstor_component *comp;
1555         struct bio *cb;
1556         struct g_provider *pp;
1557         char *addr;
1558         off_t offset, length;
1559         struct bio_queue_head bq;
1560         size_t chunk_size;      /* cached for convenience */
1561         u_int count;
1562
1563         pp = b->bio_to;
1564         sc = pp->geom->softc;
1565         KASSERT(sc != NULL, ("%s: no softc (error=%d, device=%s)", __func__,
1566             b->bio_to->error, b->bio_to->name));
1567
1568         LOG_REQ(LVL_MOREDEBUG, b, "%s", __func__);
1569
1570         switch (b->bio_cmd) {
1571         case BIO_READ:
1572         case BIO_WRITE:
1573         case BIO_DELETE:
1574                 break;
1575         default:
1576                 g_io_deliver(b, EOPNOTSUPP);
1577                 return;
1578         }
1579
1580         LOG_MSG(LVL_DEBUG2, "BIO arrived, size=%ju", b->bio_length);
1581         bioq_init(&bq);
1582
1583         chunk_size = sc->chunk_size;
1584         addr = b->bio_data;
1585         offset = b->bio_offset; /* virtual offset and length */
1586         length = b->bio_length;
1587
1588         while (length > 0) {
1589                 size_t chunk_index, in_chunk_offset, in_chunk_length;
1590                 struct virstor_map_entry *me;
1591
1592                 chunk_index = offset / chunk_size; /* round downwards */
1593                 in_chunk_offset = offset % chunk_size;
1594                 in_chunk_length = min(length, chunk_size - in_chunk_offset);
1595                 LOG_MSG(LVL_DEBUG, "Mapped %s(%ju, %ju) to (%zu,%zu,%zu)",
1596                     b->bio_cmd == BIO_READ ? "R" : "W",
1597                     offset, length,
1598                     chunk_index, in_chunk_offset, in_chunk_length);
1599                 me = &sc->map[chunk_index];
1600
1601                 if (b->bio_cmd == BIO_READ || b->bio_cmd == BIO_DELETE) {
1602                         if ((me->flags & VIRSTOR_MAP_ALLOCATED) == 0) {
1603                                 /* Reads from unallocated chunks return zeroed
1604                                  * buffers */
1605                                 if (b->bio_cmd == BIO_READ)
1606                                         bzero(addr, in_chunk_length);
1607                         } else {
1608                                 comp = &sc->components[me->provider_no];
1609
1610                                 cb = g_clone_bio(b);
1611                                 if (cb == NULL) {
1612                                         bioq_dismantle(&bq);
1613                                         if (b->bio_error == 0)
1614                                                 b->bio_error = ENOMEM;
1615                                         g_io_deliver(b, b->bio_error);
1616                                         return;
1617                                 }
1618                                 cb->bio_to = comp->gcons->provider;
1619                                 cb->bio_done = g_virstor_done;
1620                                 cb->bio_offset =
1621                                     (off_t)me->provider_chunk * (off_t)chunk_size
1622                                     + in_chunk_offset;
1623                                 cb->bio_length = in_chunk_length;
1624                                 cb->bio_data = addr;
1625                                 cb->bio_caller1 = comp;
1626                                 bioq_disksort(&bq, cb);
1627                         }
1628                 } else { /* handle BIO_WRITE */
1629                         KASSERT(b->bio_cmd == BIO_WRITE,
1630                             ("%s: Unknown command %d", __func__,
1631                             b->bio_cmd));
1632
1633                         if ((me->flags & VIRSTOR_MAP_ALLOCATED) == 0) {
1634                                 /* We have a virtual chunk, represented by
1635                                  * the "me" entry, but it's not yet allocated
1636                                  * (tied to) a physical chunk. So do it now. */
1637                                 struct virstor_map_entry *data_me;
1638                                 u_int phys_chunk, comp_no;
1639                                 off_t s_offset;
1640                                 int error;
1641
1642                                 error = allocate_chunk(sc, &comp, &comp_no,
1643                                     &phys_chunk);
1644                                 if (error != 0) {
1645                                         /* We cannot allocate a physical chunk
1646                                          * to satisfy this request, so we'll
1647                                          * delay it to when we can...
1648                                          * XXX: this will prevent the fs from
1649                                          * being umounted! */
1650                                         struct g_virstor_bio_q *biq;
1651                                         biq = malloc(sizeof *biq, M_GVIRSTOR,
1652                                             M_NOWAIT);
1653                                         if (biq == NULL) {
1654                                                 bioq_dismantle(&bq);
1655                                                 if (b->bio_error == 0)
1656                                                         b->bio_error = ENOMEM;
1657                                                 g_io_deliver(b, b->bio_error);
1658                                                 return;
1659                                         }
1660                                         biq->bio = b;
1661                                         mtx_lock(&sc->delayed_bio_q_mtx);
1662                                         STAILQ_INSERT_TAIL(&sc->delayed_bio_q,
1663                                             biq, linkage);
1664                                         mtx_unlock(&sc->delayed_bio_q_mtx);
1665                                         LOG_MSG(LVL_WARNING, "Delaying BIO "
1666                                             "(size=%ju) until free physical "
1667                                             "space can be found on %s",
1668                                             b->bio_length,
1669                                             sc->provider->name);
1670                                         return;
1671                                 }
1672                                 LOG_MSG(LVL_DEBUG, "Allocated chunk %u on %s "
1673                                     "for %s",
1674                                     phys_chunk,
1675                                     comp->gcons->provider->name,
1676                                     sc->provider->name);
1677
1678                                 me->provider_no = comp_no;
1679                                 me->provider_chunk = phys_chunk;
1680                                 me->flags |= VIRSTOR_MAP_ALLOCATED;
1681
1682                                 cb = g_clone_bio(b);
1683                                 if (cb == NULL) {
1684                                         me->flags &= ~VIRSTOR_MAP_ALLOCATED;
1685                                         me->provider_no = 0;
1686                                         me->provider_chunk = 0;
1687                                         bioq_dismantle(&bq);
1688                                         if (b->bio_error == 0)
1689                                                 b->bio_error = ENOMEM;
1690                                         g_io_deliver(b, b->bio_error);
1691                                         return;
1692                                 }
1693
1694                                 /* The allocation table is stored continuously
1695                                  * at the start of the drive. We need to
1696                                  * calculate the offset of the sector that holds
1697                                  * this map entry both on the drive and in the
1698                                  * map array.
1699                                  * sc_offset will end up pointing to the drive
1700                                  * sector. */
1701                                 s_offset = chunk_index * sizeof *me;
1702                                 s_offset = (s_offset / sc->sectorsize) *
1703                                     sc->sectorsize;
1704
1705                                 /* data_me points to map entry sector
1706                                  * in memory (analoguos to offset) */
1707                                 data_me = &sc->map[(chunk_index /
1708                                     sc->me_per_sector) * sc->me_per_sector];
1709
1710                                 /* Commit sector with map entry to storage */
1711                                 cb->bio_to = sc->components[0].gcons->provider;
1712                                 cb->bio_done = g_virstor_done;
1713                                 cb->bio_offset = s_offset;
1714                                 cb->bio_data = (char *)data_me;
1715                                 cb->bio_length = sc->sectorsize;
1716                                 cb->bio_caller1 = &sc->components[0];
1717                                 bioq_disksort(&bq, cb);
1718                         }
1719
1720                         comp = &sc->components[me->provider_no];
1721                         cb = g_clone_bio(b);
1722                         if (cb == NULL) {
1723                                 bioq_dismantle(&bq);
1724                                 if (b->bio_error == 0)
1725                                         b->bio_error = ENOMEM;
1726                                 g_io_deliver(b, b->bio_error);
1727                                 return;
1728                         }
1729                         /* Finally, handle the data */
1730                         cb->bio_to = comp->gcons->provider;
1731                         cb->bio_done = g_virstor_done;
1732                         cb->bio_offset = (off_t)me->provider_chunk*(off_t)chunk_size +
1733                             in_chunk_offset;
1734                         cb->bio_length = in_chunk_length;
1735                         cb->bio_data = addr;
1736                         cb->bio_caller1 = comp;
1737                         bioq_disksort(&bq, cb);
1738                 }
1739                 addr += in_chunk_length;
1740                 length -= in_chunk_length;
1741                 offset += in_chunk_length;
1742         }
1743
1744         /* Fire off bio's here */
1745         count = 0;
1746         for (cb = bioq_first(&bq); cb != NULL; cb = bioq_first(&bq)) {
1747                 bioq_remove(&bq, cb);
1748                 LOG_REQ(LVL_MOREDEBUG, cb, "Firing request");
1749                 comp = cb->bio_caller1;
1750                 cb->bio_caller1 = NULL;
1751                 LOG_MSG(LVL_DEBUG, " firing bio, offset=%ju, length=%ju",
1752                     cb->bio_offset, cb->bio_length);
1753                 g_io_request(cb, comp->gcons);
1754                 count++;
1755         }
1756         if (count == 0) { /* We handled everything locally */
1757                 b->bio_completed = b->bio_length;
1758                 g_io_deliver(b, 0);
1759         }
1760
1761 }
1762
1763 /*
1764  * Allocate a chunk from a physical provider. Returns physical component,
1765  * chunk index relative to the component and the component's index.
1766  */
1767 static int
1768 allocate_chunk(struct g_virstor_softc *sc, struct g_virstor_component **comp,
1769     u_int *comp_no_p, u_int *chunk)
1770 {
1771         u_int comp_no;
1772
1773         KASSERT(sc->curr_component < sc->n_components,
1774             ("%s: Invalid curr_component: %u",  __func__, sc->curr_component));
1775
1776         comp_no = sc->curr_component;
1777         *comp = &sc->components[comp_no];
1778         dump_component(*comp);
1779         if ((*comp)->chunk_next >= (*comp)->chunk_count) {
1780                 /* This component is full. Allocate next component */
1781                 if (comp_no >= sc->n_components-1) {
1782                         LOG_MSG(LVL_ERROR, "All physical space allocated for %s",
1783                             sc->geom->name);
1784                         return (-1);
1785                 }
1786                 (*comp)->flags &= ~VIRSTOR_PROVIDER_CURRENT;
1787                 sc->curr_component = ++comp_no;
1788
1789                 *comp = &sc->components[comp_no];
1790                 if (comp_no >= sc->n_components - g_virstor_component_watermark-1)
1791                         LOG_MSG(LVL_WARNING, "Device %s running out of components "
1792                             "(switching to %u/%u: %s)", sc->geom->name,
1793                             comp_no+1, sc->n_components,
1794                             (*comp)->gcons->provider->name);
1795                 /* Take care not to overwrite reserved chunks */
1796                 if ( (*comp)->chunk_reserved > 0 &&
1797                     (*comp)->chunk_next < (*comp)->chunk_reserved)
1798                         (*comp)->chunk_next = (*comp)->chunk_reserved;
1799
1800                 (*comp)->flags |=
1801                     VIRSTOR_PROVIDER_ALLOCATED | VIRSTOR_PROVIDER_CURRENT;
1802                 dump_component(*comp);
1803                 *comp_no_p = comp_no;
1804                 *chunk = (*comp)->chunk_next++;
1805         } else {
1806                 *comp_no_p = comp_no;
1807                 *chunk = (*comp)->chunk_next++;
1808         }
1809         return (0);
1810 }
1811
1812 /* Dump a component */
1813 static void
1814 dump_component(struct g_virstor_component *comp)
1815 {
1816
1817         if (g_virstor_debug < LVL_DEBUG2)
1818                 return;
1819         printf("Component %d: %s\n", comp->index, comp->gcons->provider->name);
1820         printf("  chunk_count: %u\n", comp->chunk_count);
1821         printf("   chunk_next: %u\n", comp->chunk_next);
1822         printf("        flags: %u\n", comp->flags);
1823 }
1824
1825 #if 0
1826 /* Dump a map entry */
1827 static void
1828 dump_me(struct virstor_map_entry *me, unsigned int nr)
1829 {
1830         if (g_virstor_debug < LVL_DEBUG)
1831                 return;
1832         printf("VIRT. CHUNK #%d: ", nr);
1833         if ((me->flags & VIRSTOR_MAP_ALLOCATED) == 0)
1834                 printf("(unallocated)\n");
1835         else
1836                 printf("allocated at provider %u, provider_chunk %u\n",
1837                     me->provider_no, me->provider_chunk);
1838 }
1839 #endif
1840
1841 /*
1842  * Dismantle bio_queue and destroy its components
1843  */
1844 static void
1845 bioq_dismantle(struct bio_queue_head *bq)
1846 {
1847         struct bio *b;
1848
1849         for (b = bioq_first(bq); b != NULL; b = bioq_first(bq)) {
1850                 bioq_remove(bq, b);
1851                 g_destroy_bio(b);
1852         }
1853 }
1854
1855 /*
1856  * The function that shouldn't be called.
1857  * When this is called, the stack is already garbled because of
1858  * argument mismatch. There's nothing to do now but panic, which is
1859  * accidentally the whole purpose of this function.
1860  * Motivation: to guard from accidentally calling geom methods when
1861  * they shouldn't be called. (see g_..._taste)
1862  */
1863 static void
1864 invalid_call(void)
1865 {
1866         panic("invalid_call() has just been called. Something's fishy here.");
1867 }
1868
1869 DECLARE_GEOM_CLASS(g_virstor_class, g_virstor); /* Let there be light */