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