sys/geom/virstor/g_virstor.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   3  *
   4  * Copyright (c) 2006-2007 Ivan Voras <ivoras@freebsd.org>
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  */
  28
  29 /* Implementation notes:
  30  * - "Components" are wrappers around providers that make up the
  31  *   virtual storage (i.e. a virstor has "physical" components)
  32  */
  33
  34 #include <sys/cdefs.h>
  35 __FBSDID("$FreeBSD$");
  36
  37 #include <sys/param.h>
  38 #include <sys/systm.h>
  39 #include <sys/kernel.h>
  40 #include <sys/module.h>
  41 #include <sys/lock.h>
  42 #include <sys/mutex.h>
  43 #include <sys/sx.h>
  44 #include <sys/bio.h>
  45 #include <sys/sbuf.h>
  46 #include <sys/sysctl.h>
  47 #include <sys/malloc.h>
  48 #include <sys/time.h>
  49 #include <sys/proc.h>
  50 #include <sys/kthread.h>
  51 #include <sys/mutex.h>
  52 #include <vm/uma.h>
  53 #include <geom/geom.h>
  54 #include <geom/geom_dbg.h>
  55
  56 #include <geom/virstor/g_virstor.h>
  57 #include <geom/virstor/g_virstor_md.h>
  58
  59 FEATURE(g_virstor, "GEOM virtual storage support");
  60
  61 /* Declare malloc(9) label */
  62 static MALLOC_DEFINE(M_GVIRSTOR, "gvirstor", "GEOM_VIRSTOR Data");
  63
  64 /* GEOM class methods */
  65 static g_init_t g_virstor_init;
  66 static g_fini_t g_virstor_fini;
  67 static g_taste_t g_virstor_taste;
  68 static g_ctl_req_t g_virstor_config;
  69 static g_ctl_destroy_geom_t g_virstor_destroy_geom;
  70
  71 /* Declare & initialize class structure ("geom class") */
  72 struct g_class g_virstor_class = {
  73         .name =         G_VIRSTOR_CLASS_NAME,
  74         .version =      G_VERSION,
  75         .init =         g_virstor_init,
  76         .fini =         g_virstor_fini,
  77         .taste =        g_virstor_taste,
  78         .ctlreq =       g_virstor_config,
  79         .destroy_geom = g_virstor_destroy_geom
  80         /* The .dumpconf and the rest are only usable for a geom instance, so
  81          * they will be set when such instance is created. */
  82 };
  83
  84 /* Declare sysctl's and loader tunables */
  85 SYSCTL_DECL(_kern_geom);
  86 static SYSCTL_NODE(_kern_geom, OID_AUTO, virstor,
  87     CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
  88     "GEOM_GVIRSTOR information");
  89
  90 static u_int g_virstor_debug = 2; /* XXX: lower to 2 when released to public */
  91 SYSCTL_UINT(_kern_geom_virstor, OID_AUTO, debug, CTLFLAG_RWTUN, &g_virstor_debug,
  92     0, "Debug level (2=production, 5=normal, 15=excessive)");
  93
  94 static u_int g_virstor_chunk_watermark = 100;
  95 SYSCTL_UINT(_kern_geom_virstor, OID_AUTO, chunk_watermark, CTLFLAG_RWTUN,
  96     &g_virstor_chunk_watermark, 0,
  97     "Minimum number of free chunks before issuing administrative warning");
  98
  99 static u_int g_virstor_component_watermark = 1;
 100 SYSCTL_UINT(_kern_geom_virstor, OID_AUTO, component_watermark, CTLFLAG_RWTUN,
 101     &g_virstor_component_watermark, 0,
 102     "Minimum number of free components before issuing administrative warning");
 103
 104 static int read_metadata(struct g_consumer *, struct g_virstor_metadata *);
 105 static void write_metadata(struct g_consumer *, struct g_virstor_metadata *);
 106 static int clear_metadata(struct g_virstor_component *);
 107 static int add_provider_to_geom(struct g_virstor_softc *, struct g_provider *,
 108     struct g_virstor_metadata *);
 109 static struct g_geom *create_virstor_geom(struct g_class *,
 110     struct g_virstor_metadata *);
 111 static void virstor_check_and_run(struct g_virstor_softc *);
 112 static u_int virstor_valid_components(struct g_virstor_softc *);
 113 static int virstor_geom_destroy(struct g_virstor_softc *, boolean_t,
 114     boolean_t);
 115 static void remove_component(struct g_virstor_softc *,
 116     struct g_virstor_component *, boolean_t);
 117 static void bioq_dismantle(struct bio_queue_head *);
 118 static int allocate_chunk(struct g_virstor_softc *,
 119     struct g_virstor_component **, u_int *, u_int *);
 120 static void delay_destroy_consumer(void *, int);
 121 static void dump_component(struct g_virstor_component *comp);
 122 #if 0
 123 static void dump_me(struct virstor_map_entry *me, unsigned int nr);
 124 #endif
 125
 126 static void virstor_ctl_stop(struct gctl_req *, struct g_class *);
 127 static void virstor_ctl_add(struct gctl_req *, struct g_class *);
 128 static void virstor_ctl_remove(struct gctl_req *, struct g_class *);
 129 static struct g_virstor_softc * virstor_find_geom(const struct g_class *,
 130     const char *);
 131 static void update_metadata(struct g_virstor_softc *);
 132 static void fill_metadata(struct g_virstor_softc *, struct g_virstor_metadata *,
 133     u_int, u_int);
 134
 135 static void g_virstor_orphan(struct g_consumer *);
 136 static int g_virstor_access(struct g_provider *, int, int, int);
 137 static void g_virstor_start(struct bio *);
 138 static void g_virstor_dumpconf(struct sbuf *, const char *, struct g_geom *,
 139     struct g_consumer *, struct g_provider *);
 140 static void g_virstor_done(struct bio *);
 141
 142 static void invalid_call(void);
 143 /*
 144  * Initialise GEOM class (per-class callback)
 145  */
 146 static void
 147 g_virstor_init(struct g_class *mp __unused)
 148 {
 149
 150         /* Catch map struct size mismatch at compile time; Map entries must
 151          * fit into MAXPHYS exactly, with no wasted space. */
 152         CTASSERT(VIRSTOR_MAP_BLOCK_ENTRIES*VIRSTOR_MAP_ENTRY_SIZE == MAXPHYS);
 153
 154         /* Init UMA zones, TAILQ's, other global vars */
 155 }
 156
 157 /*
 158  * Finalise GEOM class (per-class callback)
 159  */
 160 static void
 161 g_virstor_fini(struct g_class *mp __unused)
 162 {
 163
 164         /* Deinit UMA zones & global vars */
 165 }
 166
 167 /*
 168  * Config (per-class callback)
 169  */
 170 static void
 171 g_virstor_config(struct gctl_req *req, struct g_class *cp, char const *verb)
 172 {
 173         uint32_t *version;
 174
 175         g_topology_assert();
 176
 177         version = gctl_get_paraml(req, "version", sizeof(*version));
 178         if (version == NULL) {
 179                 gctl_error(req, "Failed to get 'version' argument");
 180                 return;
 181         }
 182         if (*version != G_VIRSTOR_VERSION) {
 183                 gctl_error(req, "Userland and kernel versions out of sync");
 184                 return;
 185         }
 186
 187         g_topology_unlock();
 188         if (strcmp(verb, "add") == 0)
 189                 virstor_ctl_add(req, cp);
 190         else if (strcmp(verb, "stop") == 0 || strcmp(verb, "destroy") == 0)
 191                 virstor_ctl_stop(req, cp);
 192         else if (strcmp(verb, "remove") == 0)
 193                 virstor_ctl_remove(req, cp);
 194         else
 195                 gctl_error(req, "unknown verb: '%s'", verb);
 196         g_topology_lock();
 197 }
 198
 199 /*
 200  * "stop" verb from userland
 201  */
 202 static void
 203 virstor_ctl_stop(struct gctl_req *req, struct g_class *cp)
 204 {
 205         int *force, *nargs;
 206         int i;
 207
 208         nargs = gctl_get_paraml(req, "nargs", sizeof *nargs);
 209         if (nargs == NULL) {
 210                 gctl_error(req, "Error fetching argument '%s'", "nargs");
 211                 return;
 212         }
 213         if (*nargs < 1) {
 214                 gctl_error(req, "Invalid number of arguments");
 215                 return;
 216         }
 217         force = gctl_get_paraml(req, "force", sizeof *force);
 218         if (force == NULL) {
 219                 gctl_error(req, "Error fetching argument '%s'", "force");
 220                 return;
 221         }
 222
 223         g_topology_lock();
 224         for (i = 0; i < *nargs; i++) {
 225                 char param[8];
 226                 const char *name;
 227                 struct g_virstor_softc *sc;
 228                 int error;
 229
 230                 snprintf(param, sizeof(param), "arg%d", i);
 231                 name = gctl_get_asciiparam(req, param);
 232                 if (name == NULL) {
 233                         gctl_error(req, "No 'arg%d' argument", i);
 234                         g_topology_unlock();
 235                         return;
 236                 }
 237                 sc = virstor_find_geom(cp, name);
 238                 if (sc == NULL) {
 239                         gctl_error(req, "Don't know anything about '%s'", name);
 240                         g_topology_unlock();
 241                         return;
 242                 }
 243
 244                 LOG_MSG(LVL_INFO, "Stopping %s by the userland command",
 245                     sc->geom->name);
 246                 update_metadata(sc);
 247                 if ((error = virstor_geom_destroy(sc, TRUE, TRUE)) != 0) {
 248                         LOG_MSG(LVL_ERROR, "Cannot destroy %s: %d",
 249                             sc->geom->name, error);
 250                 }
 251         }
 252         g_topology_unlock();
 253 }
 254
 255 /*
 256  * "add" verb from userland - add new component(s) to the structure.
 257  * This will be done all at once in here, without going through the
 258  * .taste function for new components.
 259  */
 260 static void
 261 virstor_ctl_add(struct gctl_req *req, struct g_class *cp)
 262 {
 263         /* Note: while this is going on, I/O is being done on
 264          * the g_up and g_down threads. The idea is to make changes
 265          * to softc members in a way that can atomically activate
 266          * them all at once. */
 267         struct g_virstor_softc *sc;
 268         int *hardcode, *nargs;
 269         const char *geom_name;  /* geom to add a component to */
 270         struct g_consumer *fcp;
 271         struct g_virstor_bio_q *bq;
 272         u_int added;
 273         int error;
 274         int i;
 275
 276         nargs = gctl_get_paraml(req, "nargs", sizeof(*nargs));
 277         if (nargs == NULL) {
 278                 gctl_error(req, "Error fetching argument '%s'", "nargs");
 279                 return;
 280         }
 281         if (*nargs < 2) {
 282                 gctl_error(req, "Invalid number of arguments");
 283                 return;
 284         }
 285         hardcode = gctl_get_paraml(req, "hardcode", sizeof(*hardcode));
 286         if (hardcode == NULL) {
 287                 gctl_error(req, "Error fetching argument '%s'", "hardcode");
 288                 return;
 289         }
 290
 291         /* Find "our" geom */
 292         geom_name = gctl_get_asciiparam(req, "arg0");
 293         if (geom_name == NULL) {
 294                 gctl_error(req, "Error fetching argument '%s'", "geom_name (arg0)");
 295                 return;
 296         }
 297         sc = virstor_find_geom(cp, geom_name);
 298         if (sc == NULL) {
 299                 gctl_error(req, "Don't know anything about '%s'", geom_name);
 300                 return;
 301         }
 302
 303         if (virstor_valid_components(sc) != sc->n_components) {
 304                 LOG_MSG(LVL_ERROR, "Cannot add components to incomplete "
 305                     "virstor %s", sc->geom->name);
 306                 gctl_error(req, "Virstor %s is incomplete", sc->geom->name);
 307                 return;
 308         }
 309
 310         fcp = sc->components[0].gcons;
 311         added = 0;
 312         g_topology_lock();
 313         for (i = 1; i < *nargs; i++) {
 314                 struct g_virstor_metadata md;
 315                 char aname[8];
 316                 struct g_provider *pp;
 317                 struct g_consumer *cp;
 318                 u_int nc;
 319                 u_int j;
 320
 321                 snprintf(aname, sizeof aname, "arg%d", i);
 322                 pp = gctl_get_provider(req, aname);
 323                 if (pp == NULL) {
 324                         /* This is the most common error so be verbose about it */
 325                         if (added != 0) {
 326                                 gctl_error(req, "Invalid provider. (added"
 327                                     " %u components)", added);
 328                                 update_metadata(sc);
 329                         }
 330                         g_topology_unlock();
 331                         return;
 332                 }
 333                 cp = g_new_consumer(sc->geom);
 334                 if (cp == NULL) {
 335                         gctl_error(req, "Cannot create consumer");
 336                         g_topology_unlock();
 337                         return;
 338                 }
 339                 error = g_attach(cp, pp);
 340                 if (error != 0) {
 341                         gctl_error(req, "Cannot attach a consumer to %s",
 342                             pp->name);
 343                         g_destroy_consumer(cp);
 344                         g_topology_unlock();
 345                         return;
 346                 }
 347                 if (fcp->acr != 0 || fcp->acw != 0 || fcp->ace != 0) {
 348                         error = g_access(cp, fcp->acr, fcp->acw, fcp->ace);
 349                         if (error != 0) {
 350                                 gctl_error(req, "Access request failed for %s",
 351                                     pp->name);
 352                                 g_destroy_consumer(cp);
 353                                 g_topology_unlock();
 354                                 return;
 355                         }
 356                 }
 357                 if (fcp->provider->sectorsize != pp->sectorsize) {
 358                         gctl_error(req, "Sector size doesn't fit for %s",
 359                             pp->name);
 360                         g_destroy_consumer(cp);
 361                         g_topology_unlock();
 362                         return;
 363                 }
 364                 for (j = 0; j < sc->n_components; j++) {
 365                         if (strcmp(sc->components[j].gcons->provider->name,
 366                             pp->name) == 0) {
 367                                 gctl_error(req, "Component %s already in %s",
 368                                     pp->name, sc->geom->name);
 369                                 g_destroy_consumer(cp);
 370                                 g_topology_unlock();
 371                                 return;
 372                         }
 373                 }
 374                 sc->components = realloc(sc->components,
 375                     sizeof(*sc->components) * (sc->n_components + 1),
 376                     M_GVIRSTOR, M_WAITOK);
 377
 378                 nc = sc->n_components;
 379                 sc->components[nc].gcons = cp;
 380                 sc->components[nc].sc = sc;
 381                 sc->components[nc].index = nc;
 382                 sc->components[nc].chunk_count = cp->provider->mediasize /
 383                     sc->chunk_size;
 384                 sc->components[nc].chunk_next = 0;
 385                 sc->components[nc].chunk_reserved = 0;
 386
 387                 if (sc->components[nc].chunk_count < 4) {
 388                         gctl_error(req, "Provider too small: %s",
 389                             cp->provider->name);
 390                         g_destroy_consumer(cp);
 391                         g_topology_unlock();
 392                         return;
 393                 }
 394                 fill_metadata(sc, &md, nc, *hardcode);
 395                 write_metadata(cp, &md);
 396                 /* The new component becomes visible when n_components is
 397                  * incremented */
 398                 sc->n_components++;
 399                 added++;
 400         }
 401         /* This call to update_metadata() is critical. In case there's a
 402          * power failure in the middle of it and some components are updated
 403          * while others are not, there will be trouble on next .taste() iff
 404          * a non-updated component is detected first */
 405         update_metadata(sc);
 406         g_topology_unlock();
 407         LOG_MSG(LVL_INFO, "Added %d component(s) to %s", added,
 408             sc->geom->name);
 409         /* Fire off BIOs previously queued because there wasn't any
 410          * physical space left. If the BIOs still can't be satisfied
 411          * they will again be added to the end of the queue (during
 412          * which the mutex will be recursed) */
 413         bq = malloc(sizeof(*bq), M_GVIRSTOR, M_WAITOK);
 414         bq->bio = NULL;
 415         mtx_lock(&sc->delayed_bio_q_mtx);
 416         /* First, insert a sentinel to the queue end, so we don't
 417          * end up in an infinite loop if there's still no free
 418          * space available. */
 419         STAILQ_INSERT_TAIL(&sc->delayed_bio_q, bq, linkage);
 420         while (!STAILQ_EMPTY(&sc->delayed_bio_q)) {
 421                 bq = STAILQ_FIRST(&sc->delayed_bio_q);
 422                 if (bq->bio != NULL) {
 423                         g_virstor_start(bq->bio);
 424                         STAILQ_REMOVE_HEAD(&sc->delayed_bio_q, linkage);
 425                         free(bq, M_GVIRSTOR);
 426                 } else {
 427                         STAILQ_REMOVE_HEAD(&sc->delayed_bio_q, linkage);
 428                         free(bq, M_GVIRSTOR);
 429                         break;
 430                 }
 431         }
 432         mtx_unlock(&sc->delayed_bio_q_mtx);
 433
 434 }
 435
 436 /*
 437  * Find a geom handled by the class
 438  */
 439 static struct g_virstor_softc *
 440 virstor_find_geom(const struct g_class *cp, const char *name)
 441 {
 442         struct g_geom *gp;
 443
 444         LIST_FOREACH(gp, &cp->geom, geom) {
 445                 if (strcmp(name, gp->name) == 0)
 446                         return (gp->softc);
 447         }
 448         return (NULL);
 449 }
 450
 451 /*
 452  * Update metadata on all components to reflect the current state
 453  * of these fields:
 454  *    - chunk_next
 455  *    - flags
 456  *    - md_count
 457  * Expects things to be set up so write_metadata() can work, i.e.
 458  * the topology lock must be held.
 459  */
 460 static void
 461 update_metadata(struct g_virstor_softc *sc)
 462 {
 463         struct g_virstor_metadata md;
 464         u_int n;
 465
 466         if (virstor_valid_components(sc) != sc->n_components)
 467                 return; /* Incomplete device */
 468         LOG_MSG(LVL_DEBUG, "Updating metadata on components for %s",
 469             sc->geom->name);
 470         /* Update metadata on components */
 471         g_trace(G_T_TOPOLOGY, "%s(%s, %s)", __func__,
 472             sc->geom->class->name, sc->geom->name);
 473         g_topology_assert();
 474         for (n = 0; n < sc->n_components; n++) {
 475                 read_metadata(sc->components[n].gcons, &md);
 476                 md.chunk_next = sc->components[n].chunk_next;
 477                 md.flags = sc->components[n].flags;
 478                 md.md_count = sc->n_components;
 479                 write_metadata(sc->components[n].gcons, &md);
 480         }
 481 }
 482
 483 /*
 484  * Fills metadata (struct md) from information stored in softc and the nc'th
 485  * component of virstor
 486  */
 487 static void
 488 fill_metadata(struct g_virstor_softc *sc, struct g_virstor_metadata *md,
 489     u_int nc, u_int hardcode)
 490 {
 491         struct g_virstor_component *c;
 492
 493         bzero(md, sizeof *md);
 494         c = &sc->components[nc];
 495
 496         strncpy(md->md_magic, G_VIRSTOR_MAGIC, sizeof md->md_magic);
 497         md->md_version = G_VIRSTOR_VERSION;
 498         strncpy(md->md_name, sc->geom->name, sizeof md->md_name);
 499         md->md_id = sc->id;
 500         md->md_virsize = sc->virsize;
 501         md->md_chunk_size = sc->chunk_size;
 502         md->md_count = sc->n_components;
 503
 504         if (hardcode) {
 505                 strncpy(md->provider, c->gcons->provider->name,
 506                     sizeof md->provider);
 507         }
 508         md->no = nc;
 509         md->provsize = c->gcons->provider->mediasize;
 510         md->chunk_count = c->chunk_count;
 511         md->chunk_next = c->chunk_next;
 512         md->chunk_reserved = c->chunk_reserved;
 513         md->flags = c->flags;
 514 }
 515
 516 /*
 517  * Remove a component from virstor device.
 518  * Can only be done if the component is unallocated.
 519  */
 520 static void
 521 virstor_ctl_remove(struct gctl_req *req, struct g_class *cp)
 522 {
 523         /* As this is executed in parallel to I/O, operations on virstor
 524          * structures must be as atomic as possible. */
 525         struct g_virstor_softc *sc;
 526         int *nargs;
 527         const char *geom_name;
 528         u_int removed;
 529         int i;
 530
 531         nargs = gctl_get_paraml(req, "nargs", sizeof(*nargs));
 532         if (nargs == NULL) {
 533                 gctl_error(req, "Error fetching argument '%s'", "nargs");
 534                 return;
 535         }
 536         if (*nargs < 2) {
 537                 gctl_error(req, "Invalid number of arguments");
 538                 return;
 539         }
 540         /* Find "our" geom */
 541         geom_name = gctl_get_asciiparam(req, "arg0");
 542         if (geom_name == NULL) {
 543                 gctl_error(req, "Error fetching argument '%s'",
 544                     "geom_name (arg0)");
 545                 return;
 546         }
 547         sc = virstor_find_geom(cp, geom_name);
 548         if (sc == NULL) {
 549                 gctl_error(req, "Don't know anything about '%s'", geom_name);
 550                 return;
 551         }
 552
 553         if (virstor_valid_components(sc) != sc->n_components) {
 554                 LOG_MSG(LVL_ERROR, "Cannot remove components from incomplete "
 555                     "virstor %s", sc->geom->name);
 556                 gctl_error(req, "Virstor %s is incomplete", sc->geom->name);
 557                 return;
 558         }
 559
 560         removed = 0;
 561         for (i = 1; i < *nargs; i++) {
 562                 char param[8];
 563                 const char *prov_name;
 564                 int j, found;
 565                 struct g_virstor_component *newcomp, *compbak;
 566
 567                 snprintf(param, sizeof(param), "arg%d", i);
 568                 prov_name = gctl_get_asciiparam(req, param);
 569                 if (prov_name == NULL) {
 570                         gctl_error(req, "Error fetching argument '%s'", param);
 571                         return;
 572                 }
 573                 if (strncmp(prov_name, _PATH_DEV, sizeof(_PATH_DEV) - 1) == 0)
 574                         prov_name += sizeof(_PATH_DEV) - 1;
 575
 576                 found = -1;
 577                 for (j = 0; j < sc->n_components; j++) {
 578                         if (strcmp(sc->components[j].gcons->provider->name,
 579                             prov_name) == 0) {
 580                                 found = j;
 581                                 break;
 582                         }
 583                 }
 584                 if (found == -1) {
 585                         LOG_MSG(LVL_ERROR, "No %s component in %s",
 586                             prov_name, sc->geom->name);
 587                         continue;
 588                 }
 589
 590                 compbak = sc->components;
 591                 newcomp = malloc(sc->n_components * sizeof(*sc->components),
 592                     M_GVIRSTOR, M_WAITOK | M_ZERO);
 593                 bcopy(sc->components, newcomp, found * sizeof(*sc->components));
 594                 bcopy(&sc->components[found + 1], newcomp + found,
 595                     found * sizeof(*sc->components));
 596                 if ((sc->components[j].flags & VIRSTOR_PROVIDER_ALLOCATED) != 0) {
 597                         LOG_MSG(LVL_ERROR, "Allocated provider %s cannot be "
 598                             "removed from %s",
 599                             prov_name, sc->geom->name);
 600                         free(newcomp, M_GVIRSTOR);
 601                         /* We'll consider this non-fatal error */
 602                         continue;
 603                 }
 604                 /* Renumerate unallocated components */
 605                 for (j = 0; j < sc->n_components-1; j++) {
 606                         if ((sc->components[j].flags &
 607                             VIRSTOR_PROVIDER_ALLOCATED) == 0) {
 608                                 sc->components[j].index = j;
 609                         }
 610                 }
 611                 /* This is the critical section. If a component allocation
 612                  * event happens while both variables are not yet set,
 613                  * there will be trouble. Something will panic on encountering
 614                  * NULL sc->components[x].gcomp member.
 615                  * Luckily, component allocation happens very rarely and
 616                  * removing components is an abnormal action in any case. */
 617                 sc->components = newcomp;
 618                 sc->n_components--;
 619                 /* End critical section */
 620
 621                 g_topology_lock();
 622                 if (clear_metadata(&compbak[found]) != 0) {
 623                         LOG_MSG(LVL_WARNING, "Trouble ahead: cannot clear "
 624                             "metadata on %s", prov_name);
 625                 }
 626                 g_detach(compbak[found].gcons);
 627                 g_destroy_consumer(compbak[found].gcons);
 628                 g_topology_unlock();
 629
 630                 free(compbak, M_GVIRSTOR);
 631
 632                 removed++;
 633         }
 634
 635         /* This call to update_metadata() is critical. In case there's a
 636          * power failure in the middle of it and some components are updated
 637          * while others are not, there will be trouble on next .taste() iff
 638          * a non-updated component is detected first */
 639         g_topology_lock();
 640         update_metadata(sc);
 641         g_topology_unlock();
 642         LOG_MSG(LVL_INFO, "Removed %d component(s) from %s", removed,
 643             sc->geom->name);
 644 }
 645
 646 /*
 647  * Clear metadata sector on component
 648  */
 649 static int
 650 clear_metadata(struct g_virstor_component *comp)
 651 {
 652         char *buf;
 653         int error;
 654
 655         LOG_MSG(LVL_INFO, "Clearing metadata on %s",
 656             comp->gcons->provider->name);
 657         g_topology_assert();
 658         error = g_access(comp->gcons, 0, 1, 0);
 659         if (error != 0)
 660                 return (error);
 661         buf = malloc(comp->gcons->provider->sectorsize, M_GVIRSTOR,
 662             M_WAITOK | M_ZERO);
 663         error = g_write_data(comp->gcons,
 664             comp->gcons->provider->mediasize -
 665             comp->gcons->provider->sectorsize,
 666             buf,
 667             comp->gcons->provider->sectorsize);
 668         free(buf, M_GVIRSTOR);
 669         g_access(comp->gcons, 0, -1, 0);
 670         return (error);
 671 }
 672
 673 /*
 674  * Destroy geom forcibly.
 675  */
 676 static int
 677 g_virstor_destroy_geom(struct gctl_req *req __unused, struct g_class *mp,
 678     struct g_geom *gp)
 679 {
 680         struct g_virstor_softc *sc;
 681         int exitval;
 682
 683         sc = gp->softc;
 684         KASSERT(sc != NULL, ("%s: NULL sc", __func__));
 685
 686         exitval = 0;
 687         LOG_MSG(LVL_DEBUG, "%s called for %s, sc=%p", __func__, gp->name,
 688             gp->softc);
 689
 690         if (sc != NULL) {
 691 #ifdef INVARIANTS
 692                 char *buf;
 693                 int error;
 694                 off_t off;
 695                 int isclean, count;
 696                 int n;
 697
 698                 LOG_MSG(LVL_INFO, "INVARIANTS detected");
 699                 LOG_MSG(LVL_INFO, "Verifying allocation "
 700                     "table for %s", sc->geom->name);
 701                 count = 0;
 702                 for (n = 0; n < sc->chunk_count; n++) {
 703                         if (sc->map[n].flags || VIRSTOR_MAP_ALLOCATED != 0)
 704                                 count++;
 705                 }
 706                 LOG_MSG(LVL_INFO, "Device %s has %d allocated chunks",
 707                     sc->geom->name, count);
 708                 n = off = count = 0;
 709                 isclean = 1;
 710                 if (virstor_valid_components(sc) != sc->n_components) {
 711                         /* This is a incomplete virstor device (not all
 712                          * components have been found) */
 713                         LOG_MSG(LVL_ERROR, "Device %s is incomplete",
 714                             sc->geom->name);
 715                         goto bailout;
 716                 }
 717                 error = g_access(sc->components[0].gcons, 1, 0, 0);
 718                 KASSERT(error == 0, ("%s: g_access failed (%d)", __func__,
 719                     error));
 720                 /* Compare the whole on-disk allocation table with what's
 721                  * currently in memory */
 722                 while (n < sc->chunk_count) {
 723                         buf = g_read_data(sc->components[0].gcons, off,
 724                             sc->sectorsize, &error);
 725                         KASSERT(buf != NULL, ("g_read_data returned NULL (%d) "
 726                             "for read at %jd", error, off));
 727                         if (bcmp(buf, &sc->map[n], sc->sectorsize) != 0) {
 728                                 LOG_MSG(LVL_ERROR, "ERROR in allocation table, "
 729                                     "entry %d, offset %jd", n, off);
 730                                 isclean = 0;
 731                                 count++;
 732                         }
 733                         n += sc->me_per_sector;
 734                         off += sc->sectorsize;
 735                         g_free(buf);
 736                 }
 737                 error = g_access(sc->components[0].gcons, -1, 0, 0);
 738                 KASSERT(error == 0, ("%s: g_access failed (%d) on exit",
 739                     __func__, error));
 740                 if (isclean != 1) {
 741                         LOG_MSG(LVL_ERROR, "ALLOCATION TABLE CORRUPTED FOR %s "
 742                             "(%d sectors don't match, max %zu allocations)",
 743                             sc->geom->name, count,
 744                             count * sc->me_per_sector);
 745                 } else {
 746                         LOG_MSG(LVL_INFO, "Allocation table ok for %s",
 747                             sc->geom->name);
 748                 }
 749 bailout:
 750 #endif
 751                 update_metadata(sc);
 752                 virstor_geom_destroy(sc, FALSE, FALSE);
 753                 exitval = EAGAIN;
 754         } else
 755                 exitval = 0;
 756         return (exitval);
 757 }
 758
 759 /*
 760  * Taste event (per-class callback)
 761  * Examines a provider and creates geom instances if needed
 762  */
 763 static struct g_geom *
 764 g_virstor_taste(struct g_class *mp, struct g_provider *pp, int flags)
 765 {
 766         struct g_virstor_metadata md;
 767         struct g_geom *gp;
 768         struct g_consumer *cp;
 769         struct g_virstor_softc *sc;
 770         int error;
 771
 772         g_trace(G_T_TOPOLOGY, "%s(%s, %s)", __func__, mp->name, pp->name);
 773         g_topology_assert();
 774         LOG_MSG(LVL_DEBUG, "Tasting %s", pp->name);
 775
 776         /* We need a dummy geom to attach a consumer to the given provider */
 777         gp = g_new_geomf(mp, "virstor:taste.helper");
 778         gp->start = (void *)invalid_call;       /* XXX: hacked up so the        */
 779         gp->access = (void *)invalid_call;      /* compiler doesn't complain.   */
 780         gp->orphan = (void *)invalid_call;      /* I really want these to fail. */
 781
 782         cp = g_new_consumer(gp);
 783         g_attach(cp, pp);
 784         error = read_metadata(cp, &md);
 785         g_detach(cp);
 786         g_destroy_consumer(cp);
 787         g_destroy_geom(gp);
 788
 789         if (error != 0)
 790                 return (NULL);
 791
 792         if (strcmp(md.md_magic, G_VIRSTOR_MAGIC) != 0)
 793                 return (NULL);
 794         if (md.md_version != G_VIRSTOR_VERSION) {
 795                 LOG_MSG(LVL_ERROR, "Kernel module version invalid "
 796                     "to handle %s (%s) : %d should be %d",
 797                     md.md_name, pp->name, md.md_version, G_VIRSTOR_VERSION);
 798                 return (NULL);
 799         }
 800         if (md.provsize != pp->mediasize)
 801                 return (NULL);
 802
 803         /* If the provider name is hardcoded, use the offered provider only
 804          * if it's been offered with its proper name (the one used in
 805          * the label command). */
 806         if (md.provider[0] != '\0' &&
 807             !g_compare_names(md.provider, pp->name))
 808                 return (NULL);
 809
 810         /* Iterate all geoms this class already knows about to see if a new
 811          * geom instance of this class needs to be created (in case the provider
 812          * is first from a (possibly) multi-consumer geom) or it just needs
 813          * to be added to an existing instance. */
 814         sc = NULL;
 815         gp = NULL;
 816         LIST_FOREACH(gp, &mp->geom, geom) {
 817                 sc = gp->softc;
 818                 if (sc == NULL)
 819                         continue;
 820                 if (strcmp(md.md_name, sc->geom->name) != 0)
 821                         continue;
 822                 if (md.md_id != sc->id)
 823                         continue;
 824                 break;
 825         }
 826         if (gp != NULL) { /* We found an existing geom instance; add to it */
 827                 LOG_MSG(LVL_INFO, "Adding %s to %s", pp->name, md.md_name);
 828                 error = add_provider_to_geom(sc, pp, &md);
 829                 if (error != 0) {
 830                         LOG_MSG(LVL_ERROR, "Error adding %s to %s (error %d)",
 831                             pp->name, md.md_name, error);
 832                         return (NULL);
 833                 }
 834         } else { /* New geom instance needs to be created */
 835                 gp = create_virstor_geom(mp, &md);
 836                 if (gp == NULL) {
 837                         LOG_MSG(LVL_ERROR, "Error creating new instance of "
 838                             "class %s: %s", mp->name, md.md_name);
 839                         LOG_MSG(LVL_DEBUG, "Error creating %s at %s",
 840                             md.md_name, pp->name);
 841                         return (NULL);
 842                 }
 843                 sc = gp->softc;
 844                 LOG_MSG(LVL_INFO, "Adding %s to %s (first found)", pp->name,
 845                     md.md_name);
 846                 error = add_provider_to_geom(sc, pp, &md);
 847                 if (error != 0) {
 848                         LOG_MSG(LVL_ERROR, "Error adding %s to %s (error %d)",
 849                             pp->name, md.md_name, error);
 850                         virstor_geom_destroy(sc, TRUE, FALSE);
 851                         return (NULL);
 852                 }
 853         }
 854
 855         return (gp);
 856 }
 857
 858 /*
 859  * Destroyes consumer passed to it in arguments. Used as a callback
 860  * on g_event queue.
 861  */
 862 static void
 863 delay_destroy_consumer(void *arg, int flags __unused)
 864 {
 865         struct g_consumer *c = arg;
 866         KASSERT(c != NULL, ("%s: invalid consumer", __func__));
 867         LOG_MSG(LVL_DEBUG, "Consumer %s destroyed with delay",
 868             c->provider->name);
 869         g_detach(c);
 870         g_destroy_consumer(c);
 871 }
 872
 873 /*
 874  * Remove a component (consumer) from geom instance; If it's the first
 875  * component being removed, orphan the provider to announce geom's being
 876  * dismantled
 877  */
 878 static void
 879 remove_component(struct g_virstor_softc *sc, struct g_virstor_component *comp,
 880     boolean_t delay)
 881 {
 882         struct g_consumer *c;
 883
 884         KASSERT(comp->gcons != NULL, ("Component with no consumer in %s",
 885             sc->geom->name));
 886         c = comp->gcons;
 887
 888         comp->gcons = NULL;
 889         KASSERT(c->provider != NULL, ("%s: no provider", __func__));
 890         LOG_MSG(LVL_DEBUG, "Component %s removed from %s", c->provider->name,
 891             sc->geom->name);
 892         if (sc->provider != NULL) {
 893                 LOG_MSG(LVL_INFO, "Removing provider %s", sc->provider->name);
 894                 g_wither_provider(sc->provider, ENXIO);
 895                 sc->provider = NULL;
 896         }
 897
 898         if (c->acr > 0 || c->acw > 0 || c->ace > 0)
 899                 return;
 900         if (delay) {
 901                 /* Destroy consumer after it's tasted */
 902                 g_post_event(delay_destroy_consumer, c, M_WAITOK, NULL);
 903         } else {
 904                 g_detach(c);
 905                 g_destroy_consumer(c);
 906         }
 907 }
 908
 909 /*
 910  * Destroy geom - called internally
 911  * See g_virstor_destroy_geom for the other one
 912  */
 913 static int
 914 virstor_geom_destroy(struct g_virstor_softc *sc, boolean_t force,
 915     boolean_t delay)
 916 {
 917         struct g_provider *pp;
 918         struct g_geom *gp;
 919         u_int n;
 920
 921         g_topology_assert();
 922
 923         if (sc == NULL)
 924                 return (ENXIO);
 925
 926         pp = sc->provider;
 927         if (pp != NULL && (pp->acr != 0 || pp->acw != 0 || pp->ace != 0)) {
 928                 LOG_MSG(force ? LVL_WARNING : LVL_ERROR,
 929                     "Device %s is still open.", pp->name);
 930                 if (!force)
 931                         return (EBUSY);
 932         }
 933
 934         for (n = 0; n < sc->n_components; n++) {
 935                 if (sc->components[n].gcons != NULL)
 936                         remove_component(sc, &sc->components[n], delay);
 937         }
 938
 939         gp = sc->geom;
 940         gp->softc = NULL;
 941
 942         KASSERT(sc->provider == NULL, ("Provider still exists for %s",
 943             gp->name));
 944
 945         /* XXX: This might or might not work, since we're called with
 946          * the topology lock held. Also, it might panic the kernel if
 947          * the error'd BIO is in softupdates code. */
 948         mtx_lock(&sc->delayed_bio_q_mtx);
 949         while (!STAILQ_EMPTY(&sc->delayed_bio_q)) {
 950                 struct g_virstor_bio_q *bq;
 951                 bq = STAILQ_FIRST(&sc->delayed_bio_q);
 952                 bq->bio->bio_error = ENOSPC;
 953                 g_io_deliver(bq->bio, EIO);
 954                 STAILQ_REMOVE_HEAD(&sc->delayed_bio_q, linkage);
 955                 free(bq, M_GVIRSTOR);
 956         }
 957         mtx_unlock(&sc->delayed_bio_q_mtx);
 958         mtx_destroy(&sc->delayed_bio_q_mtx);
 959
 960         free(sc->map, M_GVIRSTOR);
 961         free(sc->components, M_GVIRSTOR);
 962         bzero(sc, sizeof *sc);
 963         free(sc, M_GVIRSTOR);
 964
 965         pp = LIST_FIRST(&gp->provider); /* We only offer one provider */
 966         if (pp == NULL || (pp->acr == 0 && pp->acw == 0 && pp->ace == 0))
 967                 LOG_MSG(LVL_DEBUG, "Device %s destroyed", gp->name);
 968
 969         g_wither_geom(gp, ENXIO);
 970
 971         return (0);
 972 }
 973
 974 /*
 975  * Utility function: read metadata & decode. Wants topology lock to be
 976  * held.
 977  */
 978 static int
 979 read_metadata(struct g_consumer *cp, struct g_virstor_metadata *md)
 980 {
 981         struct g_provider *pp;
 982         char *buf;
 983         int error;
 984
 985         g_topology_assert();
 986         error = g_access(cp, 1, 0, 0);
 987         if (error != 0)
 988                 return (error);
 989         pp = cp->provider;
 990         g_topology_unlock();
 991         buf = g_read_data(cp, pp->mediasize - pp->sectorsize, pp->sectorsize,
 992             &error);
 993         g_topology_lock();
 994         g_access(cp, -1, 0, 0);
 995         if (buf == NULL)
 996                 return (error);
 997
 998         virstor_metadata_decode(buf, md);
 999         g_free(buf);
1000
1001         return (0);
1002 }
1003
1004 /**
1005  * Utility function: encode & write metadata. Assumes topology lock is
1006  * held.
1007  *
1008  * There is no useful way of recovering from errors in this function,
1009  * not involving panicking the kernel. If the metadata cannot be written
1010  * the most we can do is notify the operator and hope he spots it and
1011  * replaces the broken drive.
1012  */
1013 static void
1014 write_metadata(struct g_consumer *cp, struct g_virstor_metadata *md)
1015 {
1016         struct g_provider *pp;
1017         char *buf;
1018         int error;
1019
1020         KASSERT(cp != NULL && md != NULL && cp->provider != NULL,
1021             ("Something's fishy in %s", __func__));
1022         LOG_MSG(LVL_DEBUG, "Writing metadata on %s", cp->provider->name);
1023         g_topology_assert();
1024         error = g_access(cp, 0, 1, 0);
1025         if (error != 0) {
1026                 LOG_MSG(LVL_ERROR, "g_access(0,1,0) failed for %s: %d",
1027                     cp->provider->name, error);
1028                 return;
1029         }
1030         pp = cp->provider;
1031
1032         buf = malloc(pp->sectorsize, M_GVIRSTOR, M_WAITOK);
1033         bzero(buf, pp->sectorsize);
1034         virstor_metadata_encode(md, buf);
1035         g_topology_unlock();
1036         error = g_write_data(cp, pp->mediasize - pp->sectorsize, buf,
1037             pp->sectorsize);
1038         g_topology_lock();
1039         g_access(cp, 0, -1, 0);
1040         free(buf, M_GVIRSTOR);
1041
1042         if (error != 0)
1043                 LOG_MSG(LVL_ERROR, "Error %d writing metadata to %s",
1044                     error, cp->provider->name);
1045 }
1046
1047 /*
1048  * Creates a new instance of this GEOM class, initialise softc
1049  */
1050 static struct g_geom *
1051 create_virstor_geom(struct g_class *mp, struct g_virstor_metadata *md)
1052 {
1053         struct g_geom *gp;
1054         struct g_virstor_softc *sc;
1055
1056         LOG_MSG(LVL_DEBUG, "Creating geom instance for %s (id=%u)",
1057             md->md_name, md->md_id);
1058
1059         if (md->md_count < 1 || md->md_chunk_size < 1 ||
1060             md->md_virsize < md->md_chunk_size) {
1061                 /* This is bogus configuration, and probably means data is
1062                  * somehow corrupted. Panic, maybe? */
1063                 LOG_MSG(LVL_ERROR, "Nonsensical metadata information for %s",
1064                     md->md_name);
1065                 return (NULL);
1066         }
1067
1068         /* Check if it's already created */
1069         LIST_FOREACH(gp, &mp->geom, geom) {
1070                 sc = gp->softc;
1071                 if (sc != NULL && strcmp(sc->geom->name, md->md_name) == 0) {
1072                         LOG_MSG(LVL_WARNING, "Geom %s already exists",
1073                             md->md_name);
1074                         if (sc->id != md->md_id) {
1075                                 LOG_MSG(LVL_ERROR,
1076                                     "Some stale or invalid components "
1077                                     "exist for virstor device named %s. "
1078                                     "You will need to <CLEAR> all stale "
1079                                     "components and maybe reconfigure "
1080                                     "the virstor device. Tune "
1081                                     "kern.geom.virstor.debug sysctl up "
1082                                     "for more information.",
1083                                     sc->geom->name);
1084                         }
1085                         return (NULL);
1086                 }
1087         }
1088         gp = g_new_geomf(mp, "%s", md->md_name);
1089         gp->softc = NULL; /* to circumevent races that test softc */
1090
1091         gp->start = g_virstor_start;
1092         gp->spoiled = g_virstor_orphan;
1093         gp->orphan = g_virstor_orphan;
1094         gp->access = g_virstor_access;
1095         gp->dumpconf = g_virstor_dumpconf;
1096
1097         sc = malloc(sizeof(*sc), M_GVIRSTOR, M_WAITOK | M_ZERO);
1098         sc->id = md->md_id;
1099         sc->n_components = md->md_count;
1100         sc->components = malloc(sizeof(struct g_virstor_component) * md->md_count,
1101             M_GVIRSTOR, M_WAITOK | M_ZERO);
1102         sc->chunk_size = md->md_chunk_size;
1103         sc->virsize = md->md_virsize;
1104         STAILQ_INIT(&sc->delayed_bio_q);
1105         mtx_init(&sc->delayed_bio_q_mtx, "gvirstor_delayed_bio_q_mtx",
1106             "gvirstor", MTX_DEF | MTX_RECURSE);
1107
1108         sc->geom = gp;
1109         sc->provider = NULL; /* virstor_check_and_run will create it */
1110         gp->softc = sc;
1111
1112         LOG_MSG(LVL_ANNOUNCE, "Device %s created", sc->geom->name);
1113
1114         return (gp);
1115 }
1116
1117 /*
1118  * Add provider to a GEOM class instance
1119  */
1120 static int
1121 add_provider_to_geom(struct g_virstor_softc *sc, struct g_provider *pp,
1122     struct g_virstor_metadata *md)
1123 {
1124         struct g_virstor_component *component;
1125         struct g_consumer *cp, *fcp;
1126         struct g_geom *gp;
1127         int error;
1128
1129         if (md->no >= sc->n_components)
1130                 return (EINVAL);
1131
1132         /* "Current" compontent */
1133         component = &(sc->components[md->no]);
1134         if (component->gcons != NULL)
1135                 return (EEXIST);
1136
1137         gp = sc->geom;
1138         fcp = LIST_FIRST(&gp->consumer);
1139
1140         cp = g_new_consumer(gp);
1141         error = g_attach(cp, pp);
1142
1143         if (error != 0) {
1144                 g_destroy_consumer(cp);
1145                 return (error);
1146         }
1147
1148         if (fcp != NULL) {
1149                 if (fcp->provider->sectorsize != pp->sectorsize) {
1150                         /* TODO: this can be made to work */
1151                         LOG_MSG(LVL_ERROR, "Provider %s of %s has invalid "
1152                             "sector size (%d)", pp->name, sc->geom->name,
1153                             pp->sectorsize);
1154                         return (EINVAL);
1155                 }
1156                 if (fcp->acr > 0 || fcp->acw || fcp->ace > 0) {
1157                         /* Replicate access permissions from first "live" consumer
1158                          * to the new one */
1159                         error = g_access(cp, fcp->acr, fcp->acw, fcp->ace);
1160                         if (error != 0) {
1161                                 g_detach(cp);
1162                                 g_destroy_consumer(cp);
1163                                 return (error);
1164                         }
1165                 }
1166         }
1167
1168         /* Bring up a new component */
1169         cp->private = component;
1170         component->gcons = cp;
1171         component->sc = sc;
1172         component->index = md->no;
1173         component->chunk_count = md->chunk_count;
1174         component->chunk_next = md->chunk_next;
1175         component->chunk_reserved = md->chunk_reserved;
1176         component->flags = md->flags;
1177
1178         LOG_MSG(LVL_DEBUG, "%s attached to %s", pp->name, sc->geom->name);
1179
1180         virstor_check_and_run(sc);
1181         return (0);
1182 }
1183
1184 /*
1185  * Check if everything's ready to create the geom provider & device entry,
1186  * create and start provider.
1187  * Called ultimately by .taste, from g_event thread
1188  */
1189 static void
1190 virstor_check_and_run(struct g_virstor_softc *sc)
1191 {
1192         off_t off;
1193         size_t n, count;
1194         int index;
1195         int error;
1196
1197         if (virstor_valid_components(sc) != sc->n_components)
1198                 return;
1199
1200         if (virstor_valid_components(sc) == 0) {
1201                 /* This is actually a candidate for panic() */
1202                 LOG_MSG(LVL_ERROR, "No valid components for %s?",
1203                     sc->provider->name);
1204                 return;
1205         }
1206
1207         sc->sectorsize = sc->components[0].gcons->provider->sectorsize;
1208
1209         /* Initialise allocation map from the first consumer */
1210         sc->chunk_count = sc->virsize / sc->chunk_size;
1211         if (sc->chunk_count * (off_t)sc->chunk_size != sc->virsize) {
1212                 LOG_MSG(LVL_WARNING, "Device %s truncated to %ju bytes",
1213                     sc->provider->name,
1214                     sc->chunk_count * (off_t)sc->chunk_size);
1215         }
1216         sc->map_size = sc->chunk_count * sizeof *(sc->map);
1217         /* The following allocation is in order of 4MB - 8MB */
1218         sc->map = malloc(sc->map_size, M_GVIRSTOR, M_WAITOK);
1219         KASSERT(sc->map != NULL, ("%s: Memory allocation error (%zu bytes) for %s",
1220             __func__, sc->map_size, sc->provider->name));
1221         sc->map_sectors = sc->map_size / sc->sectorsize;
1222
1223         count = 0;
1224         for (n = 0; n < sc->n_components; n++)
1225                 count += sc->components[n].chunk_count;
1226         LOG_MSG(LVL_INFO, "Device %s has %zu physical chunks and %zu virtual "
1227             "(%zu KB chunks)",
1228             sc->geom->name, count, sc->chunk_count, sc->chunk_size / 1024);
1229
1230         error = g_access(sc->components[0].gcons, 1, 0, 0);
1231         if (error != 0) {
1232                 LOG_MSG(LVL_ERROR, "Cannot acquire read access for %s to "
1233                     "read allocation map for %s",
1234                     sc->components[0].gcons->provider->name,
1235                     sc->geom->name);
1236                 return;
1237         }
1238         /* Read in the allocation map */
1239         LOG_MSG(LVL_DEBUG, "Reading map for %s from %s", sc->geom->name,
1240             sc->components[0].gcons->provider->name);
1241         off = count = n = 0;
1242         while (count < sc->map_size) {
1243                 struct g_virstor_map_entry *mapbuf;
1244                 size_t bs;
1245
1246                 bs = MIN(MAXPHYS, sc->map_size - count);
1247                 if (bs % sc->sectorsize != 0) {
1248                         /* Check for alignment errors */
1249                         bs = rounddown(bs, sc->sectorsize);
1250                         if (bs == 0)
1251                                 break;
1252                         LOG_MSG(LVL_ERROR, "Trouble: map is not sector-aligned "
1253                             "for %s on %s", sc->geom->name,
1254                             sc->components[0].gcons->provider->name);
1255                 }
1256                 mapbuf = g_read_data(sc->components[0].gcons, off, bs, &error);
1257                 if (mapbuf == NULL) {
1258                         free(sc->map, M_GVIRSTOR);
1259                         LOG_MSG(LVL_ERROR, "Error reading allocation map "
1260                             "for %s from %s (offset %ju) (error %d)",
1261                             sc->geom->name,
1262                             sc->components[0].gcons->provider->name,
1263                             off, error);
1264                         return;
1265                 }
1266
1267                 bcopy(mapbuf, &sc->map[n], bs);
1268                 off += bs;
1269                 count += bs;
1270                 n += bs / sizeof *(sc->map);
1271                 g_free(mapbuf);
1272         }
1273         g_access(sc->components[0].gcons, -1, 0, 0);
1274         LOG_MSG(LVL_DEBUG, "Read map for %s", sc->geom->name);
1275
1276         /* find first component with allocatable chunks */
1277         index = -1;
1278         for (n = 0; n < sc->n_components; n++) {
1279                 if (sc->components[n].chunk_next <
1280                     sc->components[n].chunk_count) {
1281                         index = n;
1282                         break;
1283                 }
1284         }
1285         if (index == -1)
1286                 /* not found? set it to the last component and handle it
1287                  * later */
1288                 index = sc->n_components - 1;
1289
1290         if (index >= sc->n_components - g_virstor_component_watermark - 1) {
1291                 LOG_MSG(LVL_WARNING, "Device %s running out of components "
1292                     "(%d/%u: %s)", sc->geom->name,
1293                     index+1,
1294                     sc->n_components,
1295                     sc->components[index].gcons->provider->name);
1296         }
1297         sc->curr_component = index;
1298
1299         if (sc->components[index].chunk_next >=
1300             sc->components[index].chunk_count - g_virstor_chunk_watermark) {
1301                 LOG_MSG(LVL_WARNING,
1302                     "Component %s of %s is running out of free space "
1303                     "(%u chunks left)",
1304                     sc->components[index].gcons->provider->name,
1305                     sc->geom->name, sc->components[index].chunk_count -
1306                     sc->components[index].chunk_next);
1307         }
1308
1309         sc->me_per_sector = sc->sectorsize / sizeof *(sc->map);
1310         if (sc->sectorsize % sizeof *(sc->map) != 0) {
1311                 LOG_MSG(LVL_ERROR,
1312                     "%s: Map entries don't fit exactly in a sector (%s)",
1313                     __func__, sc->geom->name);
1314                 return;
1315         }
1316
1317         /* Recalculate allocated chunks in components & at the same time
1318          * verify map data is sane. We could trust metadata on this, but
1319          * we want to make sure. */
1320         for (n = 0; n < sc->n_components; n++)
1321                 sc->components[n].chunk_next = sc->components[n].chunk_reserved;
1322
1323         for (n = 0; n < sc->chunk_count; n++) {
1324                 if (sc->map[n].provider_no >= sc->n_components ||
1325                         sc->map[n].provider_chunk >=
1326                         sc->components[sc->map[n].provider_no].chunk_count) {
1327                         LOG_MSG(LVL_ERROR, "%s: Invalid entry %u in map for %s",
1328                             __func__, (u_int)n, sc->geom->name);
1329                         LOG_MSG(LVL_ERROR, "%s: provider_no: %u, n_components: %u"
1330                             " provider_chunk: %u, chunk_count: %u", __func__,
1331                             sc->map[n].provider_no, sc->n_components,
1332                             sc->map[n].provider_chunk,
1333                             sc->components[sc->map[n].provider_no].chunk_count);
1334                         return;
1335                 }
1336                 if (sc->map[n].flags & VIRSTOR_MAP_ALLOCATED)
1337                         sc->components[sc->map[n].provider_no].chunk_next++;
1338         }
1339
1340         sc->provider = g_new_providerf(sc->geom, "virstor/%s",
1341             sc->geom->name);
1342
1343         sc->provider->sectorsize = sc->sectorsize;
1344         sc->provider->mediasize = sc->virsize;
1345         g_error_provider(sc->provider, 0);
1346
1347         LOG_MSG(LVL_INFO, "%s activated", sc->provider->name);
1348         LOG_MSG(LVL_DEBUG, "%s starting with current component %u, starting "
1349             "chunk %u", sc->provider->name, sc->curr_component,
1350             sc->components[sc->curr_component].chunk_next);
1351 }
1352
1353 /*
1354  * Returns count of active providers in this geom instance
1355  */
1356 static u_int
1357 virstor_valid_components(struct g_virstor_softc *sc)
1358 {
1359         unsigned int nc, i;
1360
1361         nc = 0;
1362         KASSERT(sc != NULL, ("%s: softc is NULL", __func__));
1363         KASSERT(sc->components != NULL, ("%s: sc->components is NULL", __func__));
1364         for (i = 0; i < sc->n_components; i++)
1365                 if (sc->components[i].gcons != NULL)
1366                         nc++;
1367         return (nc);
1368 }
1369
1370 /*
1371  * Called when the consumer gets orphaned (?)
1372  */
1373 static void
1374 g_virstor_orphan(struct g_consumer *cp)
1375 {
1376         struct g_virstor_softc *sc;
1377         struct g_virstor_component *comp;
1378         struct g_geom *gp;
1379
1380         g_topology_assert();
1381         gp = cp->geom;
1382         sc = gp->softc;
1383         if (sc == NULL)
1384                 return;
1385
1386         comp = cp->private;
1387         KASSERT(comp != NULL, ("%s: No component in private part of consumer",
1388             __func__));
1389         remove_component(sc, comp, FALSE);
1390         if (LIST_EMPTY(&gp->consumer))
1391                 virstor_geom_destroy(sc, TRUE, FALSE);
1392 }
1393
1394 /*
1395  * Called to notify geom when it's been opened, and for what intent
1396  */
1397 static int
1398 g_virstor_access(struct g_provider *pp, int dr, int dw, int de)
1399 {
1400         struct g_consumer *c, *c2, *tmp;
1401         struct g_virstor_softc *sc;
1402         struct g_geom *gp;
1403         int error;
1404
1405         KASSERT(pp != NULL, ("%s: NULL provider", __func__));
1406         gp = pp->geom;
1407         KASSERT(gp != NULL, ("%s: NULL geom", __func__));
1408         sc = gp->softc;
1409
1410         /* Grab an exclusive bit to propagate on our consumers on first open */
1411         if (pp->acr == 0 && pp->acw == 0 && pp->ace == 0)
1412                 de++;
1413         /* ... drop it on close */
1414         if (pp->acr + dr == 0 && pp->acw + dw == 0 && pp->ace + de == 0) {
1415                 de--;
1416                 if (sc != NULL)
1417                         update_metadata(sc);
1418         }
1419
1420         error = ENXIO;
1421         LIST_FOREACH_SAFE(c, &gp->consumer, consumer, tmp) {
1422                 error = g_access(c, dr, dw, de);
1423                 if (error != 0)
1424                         goto fail;
1425                 if (c->acr == 0 && c->acw == 0 && c->ace == 0 &&
1426                     c->flags & G_CF_ORPHAN) {
1427                         g_detach(c);
1428                         g_destroy_consumer(c);
1429                 }
1430         }
1431
1432         if (sc != NULL && LIST_EMPTY(&gp->consumer))
1433                 virstor_geom_destroy(sc, TRUE, FALSE);
1434
1435         return (error);
1436
1437 fail:
1438         /* Backout earlier changes */
1439         LIST_FOREACH(c2, &gp->consumer, consumer) {
1440                 if (c2 == c)
1441                         break;
1442                 g_access(c2, -dr, -dw, -de);
1443         }
1444         return (error);
1445 }
1446
1447 /*
1448  * Generate XML dump of current state
1449  */
1450 static void
1451 g_virstor_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp,
1452     struct g_consumer *cp, struct g_provider *pp)
1453 {
1454         struct g_virstor_softc *sc;
1455
1456         g_topology_assert();
1457         sc = gp->softc;
1458
1459         if (sc == NULL || pp != NULL)
1460                 return;
1461
1462         if (cp != NULL) {
1463                 /* For each component */
1464                 struct g_virstor_component *comp;
1465
1466                 comp = cp->private;
1467                 if (comp == NULL)
1468                         return;
1469                 sbuf_printf(sb, "%s<ComponentIndex>%u</ComponentIndex>\n",
1470                     indent, comp->index);
1471                 sbuf_printf(sb, "%s<ChunkCount>%u</ChunkCount>\n",
1472                     indent, comp->chunk_count);
1473                 sbuf_printf(sb, "%s<ChunksUsed>%u</ChunksUsed>\n",
1474                     indent, comp->chunk_next);
1475                 sbuf_printf(sb, "%s<ChunksReserved>%u</ChunksReserved>\n",
1476                     indent, comp->chunk_reserved);
1477                 sbuf_printf(sb, "%s<StorageFree>%u%%</StorageFree>\n",
1478                     indent,
1479                     comp->chunk_next > 0 ? 100 -
1480                     ((comp->chunk_next + comp->chunk_reserved) * 100) /
1481                     comp->chunk_count : 100);
1482         } else {
1483                 /* For the whole thing */
1484                 u_int count, used, i;
1485                 off_t size;
1486
1487                 count = used = size = 0;
1488                 for (i = 0; i < sc->n_components; i++) {
1489                         if (sc->components[i].gcons != NULL) {
1490                                 count += sc->components[i].chunk_count;
1491                                 used += sc->components[i].chunk_next +
1492                                     sc->components[i].chunk_reserved;
1493                                 size += sc->components[i].gcons->
1494                                     provider->mediasize;
1495                         }
1496                 }
1497
1498                 sbuf_printf(sb, "%s<Status>"
1499                     "Components=%u, Online=%u</Status>\n", indent,
1500                     sc->n_components, virstor_valid_components(sc));
1501                 sbuf_printf(sb, "%s<State>%u%% physical free</State>\n",
1502                     indent, 100-(used * 100) / count);
1503                 sbuf_printf(sb, "%s<ChunkSize>%zu</ChunkSize>\n", indent,
1504                     sc->chunk_size);
1505                 sbuf_printf(sb, "%s<PhysicalFree>%u%%</PhysicalFree>\n",
1506                     indent, used > 0 ? 100 - (used * 100) / count : 100);
1507                 sbuf_printf(sb, "%s<ChunkPhysicalCount>%u</ChunkPhysicalCount>\n",
1508                     indent, count);
1509                 sbuf_printf(sb, "%s<ChunkVirtualCount>%zu</ChunkVirtualCount>\n",
1510                     indent, sc->chunk_count);
1511                 sbuf_printf(sb, "%s<PhysicalBacking>%zu%%</PhysicalBacking>\n",
1512                     indent,
1513                     (count * 100) / sc->chunk_count);
1514                 sbuf_printf(sb, "%s<PhysicalBackingSize>%jd</PhysicalBackingSize>\n",
1515                     indent, size);
1516                 sbuf_printf(sb, "%s<VirtualSize>%jd</VirtualSize>\n", indent,
1517                     sc->virsize);
1518         }
1519 }
1520
1521 /*
1522  * GEOM .done handler
1523  * Can't use standard handler because one requested IO may
1524  * fork into additional data IOs
1525  */
1526 static void
1527 g_virstor_done(struct bio *b)
1528 {
1529         struct g_virstor_softc *sc;
1530         struct bio *parent_b;
1531
1532         parent_b = b->bio_parent;
1533         sc = parent_b->bio_to->geom->softc;
1534
1535         if (b->bio_error != 0) {
1536                 LOG_MSG(LVL_ERROR, "Error %d for offset=%ju, length=%ju, %s",
1537                     b->bio_error, b->bio_offset, b->bio_length,
1538                     b->bio_to->name);
1539                 if (parent_b->bio_error == 0)
1540                         parent_b->bio_error = b->bio_error;
1541         }
1542
1543         parent_b->bio_inbed++;
1544         parent_b->bio_completed += b->bio_completed;
1545
1546         if (parent_b->bio_children == parent_b->bio_inbed) {
1547                 parent_b->bio_completed = parent_b->bio_length;
1548                 g_io_deliver(parent_b, parent_b->bio_error);
1549         }
1550         g_destroy_bio(b);
1551 }
1552
1553 /*
1554  * I/O starts here
1555  * Called in g_down thread
1556  */
1557 static void
1558 g_virstor_start(struct bio *b)
1559 {
1560         struct g_virstor_softc *sc;
1561         struct g_virstor_component *comp;
1562         struct bio *cb;
1563         struct g_provider *pp;
1564         char *addr;
1565         off_t offset, length;
1566         struct bio_queue_head bq;
1567         size_t chunk_size;      /* cached for convenience */
1568         u_int count;
1569
1570         pp = b->bio_to;
1571         sc = pp->geom->softc;
1572         KASSERT(sc != NULL, ("%s: no softc (error=%d, device=%s)", __func__,
1573             b->bio_to->error, b->bio_to->name));
1574
1575         LOG_REQ(LVL_MOREDEBUG, b, "%s", __func__);
1576
1577         switch (b->bio_cmd) {
1578         case BIO_READ:
1579         case BIO_WRITE:
1580         case BIO_DELETE:
1581                 break;
1582         default:
1583                 g_io_deliver(b, EOPNOTSUPP);
1584                 return;
1585         }
1586
1587         LOG_MSG(LVL_DEBUG2, "BIO arrived, size=%ju", b->bio_length);
1588         bioq_init(&bq);
1589
1590         chunk_size = sc->chunk_size;
1591         addr = b->bio_data;
1592         offset = b->bio_offset; /* virtual offset and length */
1593         length = b->bio_length;
1594
1595         while (length > 0) {
1596                 size_t chunk_index, in_chunk_offset, in_chunk_length;
1597                 struct virstor_map_entry *me;
1598
1599                 chunk_index = offset / chunk_size; /* round downwards */
1600                 in_chunk_offset = offset % chunk_size;
1601                 in_chunk_length = min(length, chunk_size - in_chunk_offset);
1602                 LOG_MSG(LVL_DEBUG, "Mapped %s(%ju, %ju) to (%zu,%zu,%zu)",
1603                     b->bio_cmd == BIO_READ ? "R" : "W",
1604                     offset, length,
1605                     chunk_index, in_chunk_offset, in_chunk_length);
1606                 me = &sc->map[chunk_index];
1607
1608                 if (b->bio_cmd == BIO_READ || b->bio_cmd == BIO_DELETE) {
1609                         if ((me->flags & VIRSTOR_MAP_ALLOCATED) == 0) {
1610                                 /* Reads from unallocated chunks return zeroed
1611                                  * buffers */
1612                                 if (b->bio_cmd == BIO_READ)
1613                                         bzero(addr, in_chunk_length);
1614                         } else {
1615                                 comp = &sc->components[me->provider_no];
1616
1617                                 cb = g_clone_bio(b);
1618                                 if (cb == NULL) {
1619                                         bioq_dismantle(&bq);
1620                                         if (b->bio_error == 0)
1621                                                 b->bio_error = ENOMEM;
1622                                         g_io_deliver(b, b->bio_error);
1623                                         return;
1624                                 }
1625                                 cb->bio_to = comp->gcons->provider;
1626                                 cb->bio_done = g_virstor_done;
1627                                 cb->bio_offset =
1628                                     (off_t)me->provider_chunk * (off_t)chunk_size
1629                                     + in_chunk_offset;
1630                                 cb->bio_length = in_chunk_length;
1631                                 cb->bio_data = addr;
1632                                 cb->bio_caller1 = comp;
1633                                 bioq_disksort(&bq, cb);
1634                         }
1635                 } else { /* handle BIO_WRITE */
1636                         KASSERT(b->bio_cmd == BIO_WRITE,
1637                             ("%s: Unknown command %d", __func__,
1638                             b->bio_cmd));
1639
1640                         if ((me->flags & VIRSTOR_MAP_ALLOCATED) == 0) {
1641                                 /* We have a virtual chunk, represented by
1642                                  * the "me" entry, but it's not yet allocated
1643                                  * (tied to) a physical chunk. So do it now. */
1644                                 struct virstor_map_entry *data_me;
1645                                 u_int phys_chunk, comp_no;
1646                                 off_t s_offset;
1647                                 int error;
1648
1649                                 error = allocate_chunk(sc, &comp, &comp_no,
1650                                     &phys_chunk);
1651                                 if (error != 0) {
1652                                         /* We cannot allocate a physical chunk
1653                                          * to satisfy this request, so we'll
1654                                          * delay it to when we can...
1655                                          * XXX: this will prevent the fs from
1656                                          * being umounted! */
1657                                         struct g_virstor_bio_q *biq;
1658                                         biq = malloc(sizeof *biq, M_GVIRSTOR,
1659                                             M_NOWAIT);
1660                                         if (biq == NULL) {
1661                                                 bioq_dismantle(&bq);
1662                                                 if (b->bio_error == 0)
1663                                                         b->bio_error = ENOMEM;
1664                                                 g_io_deliver(b, b->bio_error);
1665                                                 return;
1666                                         }
1667                                         biq->bio = b;
1668                                         mtx_lock(&sc->delayed_bio_q_mtx);
1669                                         STAILQ_INSERT_TAIL(&sc->delayed_bio_q,
1670                                             biq, linkage);
1671                                         mtx_unlock(&sc->delayed_bio_q_mtx);
1672                                         LOG_MSG(LVL_WARNING, "Delaying BIO "
1673                                             "(size=%ju) until free physical "
1674                                             "space can be found on %s",
1675                                             b->bio_length,
1676                                             sc->provider->name);
1677                                         return;
1678                                 }
1679                                 LOG_MSG(LVL_DEBUG, "Allocated chunk %u on %s "
1680                                     "for %s",
1681                                     phys_chunk,
1682                                     comp->gcons->provider->name,
1683                                     sc->provider->name);
1684
1685                                 me->provider_no = comp_no;
1686                                 me->provider_chunk = phys_chunk;
1687                                 me->flags |= VIRSTOR_MAP_ALLOCATED;
1688
1689                                 cb = g_clone_bio(b);
1690                                 if (cb == NULL) {
1691                                         me->flags &= ~VIRSTOR_MAP_ALLOCATED;
1692                                         me->provider_no = 0;
1693                                         me->provider_chunk = 0;
1694                                         bioq_dismantle(&bq);
1695                                         if (b->bio_error == 0)
1696                                                 b->bio_error = ENOMEM;
1697                                         g_io_deliver(b, b->bio_error);
1698                                         return;
1699                                 }
1700
1701                                 /* The allocation table is stored continuously
1702                                  * at the start of the drive. We need to
1703                                  * calculate the offset of the sector that holds
1704                                  * this map entry both on the drive and in the
1705                                  * map array.
1706                                  * sc_offset will end up pointing to the drive
1707                                  * sector. */
1708                                 s_offset = chunk_index * sizeof *me;
1709                                 s_offset = rounddown(s_offset, sc->sectorsize);
1710
1711                                 /* data_me points to map entry sector
1712                                  * in memory (analogous to offset) */
1713                                 data_me = &sc->map[rounddown(chunk_index,
1714                                     sc->me_per_sector)];
1715
1716                                 /* Commit sector with map entry to storage */
1717                                 cb->bio_to = sc->components[0].gcons->provider;
1718                                 cb->bio_done = g_virstor_done;
1719                                 cb->bio_offset = s_offset;
1720                                 cb->bio_data = (char *)data_me;
1721                                 cb->bio_length = sc->sectorsize;
1722                                 cb->bio_caller1 = &sc->components[0];
1723                                 bioq_disksort(&bq, cb);
1724                         }
1725
1726                         comp = &sc->components[me->provider_no];
1727                         cb = g_clone_bio(b);
1728                         if (cb == NULL) {
1729                                 bioq_dismantle(&bq);
1730                                 if (b->bio_error == 0)
1731                                         b->bio_error = ENOMEM;
1732                                 g_io_deliver(b, b->bio_error);
1733                                 return;
1734                         }
1735                         /* Finally, handle the data */
1736                         cb->bio_to = comp->gcons->provider;
1737                         cb->bio_done = g_virstor_done;
1738                         cb->bio_offset = (off_t)me->provider_chunk*(off_t)chunk_size +
1739                             in_chunk_offset;
1740                         cb->bio_length = in_chunk_length;
1741                         cb->bio_data = addr;
1742                         cb->bio_caller1 = comp;
1743                         bioq_disksort(&bq, cb);
1744                 }
1745                 addr += in_chunk_length;
1746                 length -= in_chunk_length;
1747                 offset += in_chunk_length;
1748         }
1749
1750         /* Fire off bio's here */
1751         count = 0;
1752         for (cb = bioq_first(&bq); cb != NULL; cb = bioq_first(&bq)) {
1753                 bioq_remove(&bq, cb);
1754                 LOG_REQ(LVL_MOREDEBUG, cb, "Firing request");
1755                 comp = cb->bio_caller1;
1756                 cb->bio_caller1 = NULL;
1757                 LOG_MSG(LVL_DEBUG, " firing bio, offset=%ju, length=%ju",
1758                     cb->bio_offset, cb->bio_length);
1759                 g_io_request(cb, comp->gcons);
1760                 count++;
1761         }
1762         if (count == 0) { /* We handled everything locally */
1763                 b->bio_completed = b->bio_length;
1764                 g_io_deliver(b, 0);
1765         }
1766
1767 }
1768
1769 /*
1770  * Allocate a chunk from a physical provider. Returns physical component,
1771  * chunk index relative to the component and the component's index.
1772  */
1773 static int
1774 allocate_chunk(struct g_virstor_softc *sc, struct g_virstor_component **comp,
1775     u_int *comp_no_p, u_int *chunk)
1776 {
1777         u_int comp_no;
1778
1779         KASSERT(sc->curr_component < sc->n_components,
1780             ("%s: Invalid curr_component: %u",  __func__, sc->curr_component));
1781
1782         comp_no = sc->curr_component;
1783         *comp = &sc->components[comp_no];
1784         dump_component(*comp);
1785         if ((*comp)->chunk_next >= (*comp)->chunk_count) {
1786                 /* This component is full. Allocate next component */
1787                 if (comp_no >= sc->n_components-1) {
1788                         LOG_MSG(LVL_ERROR, "All physical space allocated for %s",
1789                             sc->geom->name);
1790                         return (-1);
1791                 }
1792                 (*comp)->flags &= ~VIRSTOR_PROVIDER_CURRENT;
1793                 sc->curr_component = ++comp_no;
1794
1795                 *comp = &sc->components[comp_no];
1796                 if (comp_no >= sc->n_components - g_virstor_component_watermark-1)
1797                         LOG_MSG(LVL_WARNING, "Device %s running out of components "
1798                             "(switching to %u/%u: %s)", sc->geom->name,
1799                             comp_no+1, sc->n_components,
1800                             (*comp)->gcons->provider->name);
1801                 /* Take care not to overwrite reserved chunks */
1802                 if ( (*comp)->chunk_reserved > 0 &&
1803                     (*comp)->chunk_next < (*comp)->chunk_reserved)
1804                         (*comp)->chunk_next = (*comp)->chunk_reserved;
1805
1806                 (*comp)->flags |=
1807                     VIRSTOR_PROVIDER_ALLOCATED | VIRSTOR_PROVIDER_CURRENT;
1808                 dump_component(*comp);
1809                 *comp_no_p = comp_no;
1810                 *chunk = (*comp)->chunk_next++;
1811         } else {
1812                 *comp_no_p = comp_no;
1813                 *chunk = (*comp)->chunk_next++;
1814         }
1815         return (0);
1816 }
1817
1818 /* Dump a component */
1819 static void
1820 dump_component(struct g_virstor_component *comp)
1821 {
1822
1823         if (g_virstor_debug < LVL_DEBUG2)
1824                 return;
1825         printf("Component %d: %s\n", comp->index, comp->gcons->provider->name);
1826         printf("  chunk_count: %u\n", comp->chunk_count);
1827         printf("   chunk_next: %u\n", comp->chunk_next);
1828         printf("        flags: %u\n", comp->flags);
1829 }
1830
1831 #if 0
1832 /* Dump a map entry */
1833 static void
1834 dump_me(struct virstor_map_entry *me, unsigned int nr)
1835 {
1836         if (g_virstor_debug < LVL_DEBUG)
1837                 return;
1838         printf("VIRT. CHUNK #%d: ", nr);
1839         if ((me->flags & VIRSTOR_MAP_ALLOCATED) == 0)
1840                 printf("(unallocated)\n");
1841         else
1842                 printf("allocated at provider %u, provider_chunk %u\n",
1843                     me->provider_no, me->provider_chunk);
1844 }
1845 #endif
1846
1847 /*
1848  * Dismantle bio_queue and destroy its components
1849  */
1850 static void
1851 bioq_dismantle(struct bio_queue_head *bq)
1852 {
1853         struct bio *b;
1854
1855         for (b = bioq_first(bq); b != NULL; b = bioq_first(bq)) {
1856                 bioq_remove(bq, b);
1857                 g_destroy_bio(b);
1858         }
1859 }
1860
1861 /*
1862  * The function that shouldn't be called.
1863  * When this is called, the stack is already garbled because of
1864  * argument mismatch. There's nothing to do now but panic, which is
1865  * accidentally the whole purpose of this function.
1866  * Motivation: to guard from accidentally calling geom methods when
1867  * they shouldn't be called. (see g_..._taste)
1868  */
1869 static void
1870 invalid_call(void)
1871 {
1872         panic("invalid_call() has just been called. Something's fishy here.");
1873 }
1874
1875 DECLARE_GEOM_CLASS(g_virstor_class, g_virstor); /* Let there be light */
1876 MODULE_VERSION(geom_virstor, 0);