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         MPASS(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         error = g_attach(cp, pp);
 784         if (error == 0) {
 785                 error = read_metadata(cp, &md);
 786                 g_detach(cp);
 787         }
 788         g_destroy_consumer(cp);
 789         g_destroy_geom(gp);
 790
 791         if (error != 0)
 792                 return (NULL);
 793
 794         if (strcmp(md.md_magic, G_VIRSTOR_MAGIC) != 0)
 795                 return (NULL);
 796         if (md.md_version != G_VIRSTOR_VERSION) {
 797                 LOG_MSG(LVL_ERROR, "Kernel module version invalid "
 798                     "to handle %s (%s) : %d should be %d",
 799                     md.md_name, pp->name, md.md_version, G_VIRSTOR_VERSION);
 800                 return (NULL);
 801         }
 802         if (md.provsize != pp->mediasize)
 803                 return (NULL);
 804
 805         /* If the provider name is hardcoded, use the offered provider only
 806          * if it's been offered with its proper name (the one used in
 807          * the label command). */
 808         if (md.provider[0] != '\0' &&
 809             !g_compare_names(md.provider, pp->name))
 810                 return (NULL);
 811
 812         /* Iterate all geoms this class already knows about to see if a new
 813          * geom instance of this class needs to be created (in case the provider
 814          * is first from a (possibly) multi-consumer geom) or it just needs
 815          * to be added to an existing instance. */
 816         sc = NULL;
 817         gp = NULL;
 818         LIST_FOREACH(gp, &mp->geom, geom) {
 819                 sc = gp->softc;
 820                 if (sc == NULL)
 821                         continue;
 822                 if (strcmp(md.md_name, sc->geom->name) != 0)
 823                         continue;
 824                 if (md.md_id != sc->id)
 825                         continue;
 826                 break;
 827         }
 828         if (gp != NULL) { /* We found an existing geom instance; add to it */
 829                 LOG_MSG(LVL_INFO, "Adding %s to %s", pp->name, md.md_name);
 830                 error = add_provider_to_geom(sc, pp, &md);
 831                 if (error != 0) {
 832                         LOG_MSG(LVL_ERROR, "Error adding %s to %s (error %d)",
 833                             pp->name, md.md_name, error);
 834                         return (NULL);
 835                 }
 836         } else { /* New geom instance needs to be created */
 837                 gp = create_virstor_geom(mp, &md);
 838                 if (gp == NULL) {
 839                         LOG_MSG(LVL_ERROR, "Error creating new instance of "
 840                             "class %s: %s", mp->name, md.md_name);
 841                         LOG_MSG(LVL_DEBUG, "Error creating %s at %s",
 842                             md.md_name, pp->name);
 843                         return (NULL);
 844                 }
 845                 sc = gp->softc;
 846                 LOG_MSG(LVL_INFO, "Adding %s to %s (first found)", pp->name,
 847                     md.md_name);
 848                 error = add_provider_to_geom(sc, pp, &md);
 849                 if (error != 0) {
 850                         LOG_MSG(LVL_ERROR, "Error adding %s to %s (error %d)",
 851                             pp->name, md.md_name, error);
 852                         virstor_geom_destroy(sc, TRUE, FALSE);
 853                         return (NULL);
 854                 }
 855         }
 856
 857         return (gp);
 858 }
 859
 860 /*
 861  * Destroyes consumer passed to it in arguments. Used as a callback
 862  * on g_event queue.
 863  */
 864 static void
 865 delay_destroy_consumer(void *arg, int flags __unused)
 866 {
 867         struct g_consumer *c = arg;
 868         KASSERT(c != NULL, ("%s: invalid consumer", __func__));
 869         LOG_MSG(LVL_DEBUG, "Consumer %s destroyed with delay",
 870             c->provider->name);
 871         g_detach(c);
 872         g_destroy_consumer(c);
 873 }
 874
 875 /*
 876  * Remove a component (consumer) from geom instance; If it's the first
 877  * component being removed, orphan the provider to announce geom's being
 878  * dismantled
 879  */
 880 static void
 881 remove_component(struct g_virstor_softc *sc, struct g_virstor_component *comp,
 882     boolean_t delay)
 883 {
 884         struct g_consumer *c;
 885
 886         KASSERT(comp->gcons != NULL, ("Component with no consumer in %s",
 887             sc->geom->name));
 888         c = comp->gcons;
 889
 890         comp->gcons = NULL;
 891         KASSERT(c->provider != NULL, ("%s: no provider", __func__));
 892         LOG_MSG(LVL_DEBUG, "Component %s removed from %s", c->provider->name,
 893             sc->geom->name);
 894         if (sc->provider != NULL) {
 895                 LOG_MSG(LVL_INFO, "Removing provider %s", sc->provider->name);
 896                 g_wither_provider(sc->provider, ENXIO);
 897                 sc->provider = NULL;
 898         }
 899
 900         if (c->acr > 0 || c->acw > 0 || c->ace > 0)
 901                 return;
 902         if (delay) {
 903                 /* Destroy consumer after it's tasted */
 904                 g_post_event(delay_destroy_consumer, c, M_WAITOK, NULL);
 905         } else {
 906                 g_detach(c);
 907                 g_destroy_consumer(c);
 908         }
 909 }
 910
 911 /*
 912  * Destroy geom - called internally
 913  * See g_virstor_destroy_geom for the other one
 914  */
 915 static int
 916 virstor_geom_destroy(struct g_virstor_softc *sc, boolean_t force,
 917     boolean_t delay)
 918 {
 919         struct g_provider *pp;
 920         struct g_geom *gp;
 921         u_int n;
 922
 923         g_topology_assert();
 924
 925         if (sc == NULL)
 926                 return (ENXIO);
 927
 928         pp = sc->provider;
 929         if (pp != NULL && (pp->acr != 0 || pp->acw != 0 || pp->ace != 0)) {
 930                 LOG_MSG(force ? LVL_WARNING : LVL_ERROR,
 931                     "Device %s is still open.", pp->name);
 932                 if (!force)
 933                         return (EBUSY);
 934         }
 935
 936         for (n = 0; n < sc->n_components; n++) {
 937                 if (sc->components[n].gcons != NULL)
 938                         remove_component(sc, &sc->components[n], delay);
 939         }
 940
 941         gp = sc->geom;
 942         gp->softc = NULL;
 943
 944         KASSERT(sc->provider == NULL, ("Provider still exists for %s",
 945             gp->name));
 946
 947         /* XXX: This might or might not work, since we're called with
 948          * the topology lock held. Also, it might panic the kernel if
 949          * the error'd BIO is in softupdates code. */
 950         mtx_lock(&sc->delayed_bio_q_mtx);
 951         while (!STAILQ_EMPTY(&sc->delayed_bio_q)) {
 952                 struct g_virstor_bio_q *bq;
 953                 bq = STAILQ_FIRST(&sc->delayed_bio_q);
 954                 bq->bio->bio_error = ENOSPC;
 955                 g_io_deliver(bq->bio, EIO);
 956                 STAILQ_REMOVE_HEAD(&sc->delayed_bio_q, linkage);
 957                 free(bq, M_GVIRSTOR);
 958         }
 959         mtx_unlock(&sc->delayed_bio_q_mtx);
 960         mtx_destroy(&sc->delayed_bio_q_mtx);
 961
 962         free(sc->map, M_GVIRSTOR);
 963         free(sc->components, M_GVIRSTOR);
 964         bzero(sc, sizeof *sc);
 965         free(sc, M_GVIRSTOR);
 966
 967         pp = LIST_FIRST(&gp->provider); /* We only offer one provider */
 968         if (pp == NULL || (pp->acr == 0 && pp->acw == 0 && pp->ace == 0))
 969                 LOG_MSG(LVL_DEBUG, "Device %s destroyed", gp->name);
 970
 971         g_wither_geom(gp, ENXIO);
 972
 973         return (0);
 974 }
 975
 976 /*
 977  * Utility function: read metadata & decode. Wants topology lock to be
 978  * held.
 979  */
 980 static int
 981 read_metadata(struct g_consumer *cp, struct g_virstor_metadata *md)
 982 {
 983         struct g_provider *pp;
 984         char *buf;
 985         int error;
 986
 987         g_topology_assert();
 988         error = g_access(cp, 1, 0, 0);
 989         if (error != 0)
 990                 return (error);
 991         pp = cp->provider;
 992         g_topology_unlock();
 993         buf = g_read_data(cp, pp->mediasize - pp->sectorsize, pp->sectorsize,
 994             &error);
 995         g_topology_lock();
 996         g_access(cp, -1, 0, 0);
 997         if (buf == NULL)
 998                 return (error);
 999
1000         virstor_metadata_decode(buf, md);
1001         g_free(buf);
1002
1003         return (0);
1004 }
1005
1006 /**
1007  * Utility function: encode & write metadata. Assumes topology lock is
1008  * held.
1009  *
1010  * There is no useful way of recovering from errors in this function,
1011  * not involving panicking the kernel. If the metadata cannot be written
1012  * the most we can do is notify the operator and hope he spots it and
1013  * replaces the broken drive.
1014  */
1015 static void
1016 write_metadata(struct g_consumer *cp, struct g_virstor_metadata *md)
1017 {
1018         struct g_provider *pp;
1019         char *buf;
1020         int error;
1021
1022         KASSERT(cp != NULL && md != NULL && cp->provider != NULL,
1023             ("Something's fishy in %s", __func__));
1024         LOG_MSG(LVL_DEBUG, "Writing metadata on %s", cp->provider->name);
1025         g_topology_assert();
1026         error = g_access(cp, 0, 1, 0);
1027         if (error != 0) {
1028                 LOG_MSG(LVL_ERROR, "g_access(0,1,0) failed for %s: %d",
1029                     cp->provider->name, error);
1030                 return;
1031         }
1032         pp = cp->provider;
1033
1034         buf = malloc(pp->sectorsize, M_GVIRSTOR, M_WAITOK);
1035         bzero(buf, pp->sectorsize);
1036         virstor_metadata_encode(md, buf);
1037         g_topology_unlock();
1038         error = g_write_data(cp, pp->mediasize - pp->sectorsize, buf,
1039             pp->sectorsize);
1040         g_topology_lock();
1041         g_access(cp, 0, -1, 0);
1042         free(buf, M_GVIRSTOR);
1043
1044         if (error != 0)
1045                 LOG_MSG(LVL_ERROR, "Error %d writing metadata to %s",
1046                     error, cp->provider->name);
1047 }
1048
1049 /*
1050  * Creates a new instance of this GEOM class, initialise softc
1051  */
1052 static struct g_geom *
1053 create_virstor_geom(struct g_class *mp, struct g_virstor_metadata *md)
1054 {
1055         struct g_geom *gp;
1056         struct g_virstor_softc *sc;
1057
1058         LOG_MSG(LVL_DEBUG, "Creating geom instance for %s (id=%u)",
1059             md->md_name, md->md_id);
1060
1061         if (md->md_count < 1 || md->md_chunk_size < 1 ||
1062             md->md_virsize < md->md_chunk_size) {
1063                 /* This is bogus configuration, and probably means data is
1064                  * somehow corrupted. Panic, maybe? */
1065                 LOG_MSG(LVL_ERROR, "Nonsensical metadata information for %s",
1066                     md->md_name);
1067                 return (NULL);
1068         }
1069
1070         /* Check if it's already created */
1071         LIST_FOREACH(gp, &mp->geom, geom) {
1072                 sc = gp->softc;
1073                 if (sc != NULL && strcmp(sc->geom->name, md->md_name) == 0) {
1074                         LOG_MSG(LVL_WARNING, "Geom %s already exists",
1075                             md->md_name);
1076                         if (sc->id != md->md_id) {
1077                                 LOG_MSG(LVL_ERROR,
1078                                     "Some stale or invalid components "
1079                                     "exist for virstor device named %s. "
1080                                     "You will need to <CLEAR> all stale "
1081                                     "components and maybe reconfigure "
1082                                     "the virstor device. Tune "
1083                                     "kern.geom.virstor.debug sysctl up "
1084                                     "for more information.",
1085                                     sc->geom->name);
1086                         }
1087                         return (NULL);
1088                 }
1089         }
1090         gp = g_new_geomf(mp, "%s", md->md_name);
1091         gp->softc = NULL; /* to circumevent races that test softc */
1092
1093         gp->start = g_virstor_start;
1094         gp->spoiled = g_virstor_orphan;
1095         gp->orphan = g_virstor_orphan;
1096         gp->access = g_virstor_access;
1097         gp->dumpconf = g_virstor_dumpconf;
1098
1099         sc = malloc(sizeof(*sc), M_GVIRSTOR, M_WAITOK | M_ZERO);
1100         sc->id = md->md_id;
1101         sc->n_components = md->md_count;
1102         sc->components = malloc(sizeof(struct g_virstor_component) * md->md_count,
1103             M_GVIRSTOR, M_WAITOK | M_ZERO);
1104         sc->chunk_size = md->md_chunk_size;
1105         sc->virsize = md->md_virsize;
1106         STAILQ_INIT(&sc->delayed_bio_q);
1107         mtx_init(&sc->delayed_bio_q_mtx, "gvirstor_delayed_bio_q_mtx",
1108             "gvirstor", MTX_DEF | MTX_RECURSE);
1109
1110         sc->geom = gp;
1111         sc->provider = NULL; /* virstor_check_and_run will create it */
1112         gp->softc = sc;
1113
1114         LOG_MSG(LVL_ANNOUNCE, "Device %s created", sc->geom->name);
1115
1116         return (gp);
1117 }
1118
1119 /*
1120  * Add provider to a GEOM class instance
1121  */
1122 static int
1123 add_provider_to_geom(struct g_virstor_softc *sc, struct g_provider *pp,
1124     struct g_virstor_metadata *md)
1125 {
1126         struct g_virstor_component *component;
1127         struct g_consumer *cp, *fcp;
1128         struct g_geom *gp;
1129         int error;
1130
1131         if (md->no >= sc->n_components)
1132                 return (EINVAL);
1133
1134         /* "Current" compontent */
1135         component = &(sc->components[md->no]);
1136         if (component->gcons != NULL)
1137                 return (EEXIST);
1138
1139         gp = sc->geom;
1140         fcp = LIST_FIRST(&gp->consumer);
1141
1142         cp = g_new_consumer(gp);
1143         error = g_attach(cp, pp);
1144
1145         if (error != 0) {
1146                 g_destroy_consumer(cp);
1147                 return (error);
1148         }
1149
1150         if (fcp != NULL) {
1151                 if (fcp->provider->sectorsize != pp->sectorsize) {
1152                         /* TODO: this can be made to work */
1153                         LOG_MSG(LVL_ERROR, "Provider %s of %s has invalid "
1154                             "sector size (%d)", pp->name, sc->geom->name,
1155                             pp->sectorsize);
1156                         return (EINVAL);
1157                 }
1158                 if (fcp->acr > 0 || fcp->acw || fcp->ace > 0) {
1159                         /* Replicate access permissions from first "live" consumer
1160                          * to the new one */
1161                         error = g_access(cp, fcp->acr, fcp->acw, fcp->ace);
1162                         if (error != 0) {
1163                                 g_detach(cp);
1164                                 g_destroy_consumer(cp);
1165                                 return (error);
1166                         }
1167                 }
1168         }
1169
1170         /* Bring up a new component */
1171         cp->private = component;
1172         component->gcons = cp;
1173         component->sc = sc;
1174         component->index = md->no;
1175         component->chunk_count = md->chunk_count;
1176         component->chunk_next = md->chunk_next;
1177         component->chunk_reserved = md->chunk_reserved;
1178         component->flags = md->flags;
1179
1180         LOG_MSG(LVL_DEBUG, "%s attached to %s", pp->name, sc->geom->name);
1181
1182         virstor_check_and_run(sc);
1183         return (0);
1184 }
1185
1186 /*
1187  * Check if everything's ready to create the geom provider & device entry,
1188  * create and start provider.
1189  * Called ultimately by .taste, from g_event thread
1190  */
1191 static void
1192 virstor_check_and_run(struct g_virstor_softc *sc)
1193 {
1194         off_t off;
1195         size_t n, count;
1196         int index;
1197         int error;
1198
1199         if (virstor_valid_components(sc) != sc->n_components)
1200                 return;
1201
1202         if (virstor_valid_components(sc) == 0) {
1203                 /* This is actually a candidate for panic() */
1204                 LOG_MSG(LVL_ERROR, "No valid components for %s?",
1205                     sc->provider->name);
1206                 return;
1207         }
1208
1209         sc->sectorsize = sc->components[0].gcons->provider->sectorsize;
1210
1211         /* Initialise allocation map from the first consumer */
1212         sc->chunk_count = sc->virsize / sc->chunk_size;
1213         if (sc->chunk_count * (off_t)sc->chunk_size != sc->virsize) {
1214                 LOG_MSG(LVL_WARNING, "Device %s truncated to %ju bytes",
1215                     sc->provider->name,
1216                     sc->chunk_count * (off_t)sc->chunk_size);
1217         }
1218         sc->map_size = sc->chunk_count * sizeof *(sc->map);
1219         /* The following allocation is in order of 4MB - 8MB */
1220         sc->map = malloc(sc->map_size, M_GVIRSTOR, M_WAITOK);
1221         KASSERT(sc->map != NULL, ("%s: Memory allocation error (%zu bytes) for %s",
1222             __func__, sc->map_size, sc->provider->name));
1223         sc->map_sectors = sc->map_size / sc->sectorsize;
1224
1225         count = 0;
1226         for (n = 0; n < sc->n_components; n++)
1227                 count += sc->components[n].chunk_count;
1228         LOG_MSG(LVL_INFO, "Device %s has %zu physical chunks and %zu virtual "
1229             "(%zu KB chunks)",
1230             sc->geom->name, count, sc->chunk_count, sc->chunk_size / 1024);
1231
1232         error = g_access(sc->components[0].gcons, 1, 0, 0);
1233         if (error != 0) {
1234                 LOG_MSG(LVL_ERROR, "Cannot acquire read access for %s to "
1235                     "read allocation map for %s",
1236                     sc->components[0].gcons->provider->name,
1237                     sc->geom->name);
1238                 return;
1239         }
1240         /* Read in the allocation map */
1241         LOG_MSG(LVL_DEBUG, "Reading map for %s from %s", sc->geom->name,
1242             sc->components[0].gcons->provider->name);
1243         off = count = n = 0;
1244         while (count < sc->map_size) {
1245                 struct g_virstor_map_entry *mapbuf;
1246                 size_t bs;
1247
1248                 bs = MIN(maxphys, sc->map_size - count);
1249                 if (bs % sc->sectorsize != 0) {
1250                         /* Check for alignment errors */
1251                         bs = rounddown(bs, sc->sectorsize);
1252                         if (bs == 0)
1253                                 break;
1254                         LOG_MSG(LVL_ERROR, "Trouble: map is not sector-aligned "
1255                             "for %s on %s", sc->geom->name,
1256                             sc->components[0].gcons->provider->name);
1257                 }
1258                 mapbuf = g_read_data(sc->components[0].gcons, off, bs, &error);
1259                 if (mapbuf == NULL) {
1260                         free(sc->map, M_GVIRSTOR);
1261                         LOG_MSG(LVL_ERROR, "Error reading allocation map "
1262                             "for %s from %s (offset %ju) (error %d)",
1263                             sc->geom->name,
1264                             sc->components[0].gcons->provider->name,
1265                             off, error);
1266                         return;
1267                 }
1268
1269                 bcopy(mapbuf, &sc->map[n], bs);
1270                 off += bs;
1271                 count += bs;
1272                 n += bs / sizeof *(sc->map);
1273                 g_free(mapbuf);
1274         }
1275         g_access(sc->components[0].gcons, -1, 0, 0);
1276         LOG_MSG(LVL_DEBUG, "Read map for %s", sc->geom->name);
1277
1278         /* find first component with allocatable chunks */
1279         index = -1;
1280         for (n = 0; n < sc->n_components; n++) {
1281                 if (sc->components[n].chunk_next <
1282                     sc->components[n].chunk_count) {
1283                         index = n;
1284                         break;
1285                 }
1286         }
1287         if (index == -1)
1288                 /* not found? set it to the last component and handle it
1289                  * later */
1290                 index = sc->n_components - 1;
1291
1292         if (index >= sc->n_components - g_virstor_component_watermark - 1) {
1293                 LOG_MSG(LVL_WARNING, "Device %s running out of components "
1294                     "(%d/%u: %s)", sc->geom->name,
1295                     index+1,
1296                     sc->n_components,
1297                     sc->components[index].gcons->provider->name);
1298         }
1299         sc->curr_component = index;
1300
1301         if (sc->components[index].chunk_next >=
1302             sc->components[index].chunk_count - g_virstor_chunk_watermark) {
1303                 LOG_MSG(LVL_WARNING,
1304                     "Component %s of %s is running out of free space "
1305                     "(%u chunks left)",
1306                     sc->components[index].gcons->provider->name,
1307                     sc->geom->name, sc->components[index].chunk_count -
1308                     sc->components[index].chunk_next);
1309         }
1310
1311         sc->me_per_sector = sc->sectorsize / sizeof *(sc->map);
1312         if (sc->sectorsize % sizeof *(sc->map) != 0) {
1313                 LOG_MSG(LVL_ERROR,
1314                     "%s: Map entries don't fit exactly in a sector (%s)",
1315                     __func__, sc->geom->name);
1316                 return;
1317         }
1318
1319         /* Recalculate allocated chunks in components & at the same time
1320          * verify map data is sane. We could trust metadata on this, but
1321          * we want to make sure. */
1322         for (n = 0; n < sc->n_components; n++)
1323                 sc->components[n].chunk_next = sc->components[n].chunk_reserved;
1324
1325         for (n = 0; n < sc->chunk_count; n++) {
1326                 if (sc->map[n].provider_no >= sc->n_components ||
1327                         sc->map[n].provider_chunk >=
1328                         sc->components[sc->map[n].provider_no].chunk_count) {
1329                         LOG_MSG(LVL_ERROR, "%s: Invalid entry %u in map for %s",
1330                             __func__, (u_int)n, sc->geom->name);
1331                         LOG_MSG(LVL_ERROR, "%s: provider_no: %u, n_components: %u"
1332                             " provider_chunk: %u, chunk_count: %u", __func__,
1333                             sc->map[n].provider_no, sc->n_components,
1334                             sc->map[n].provider_chunk,
1335                             sc->components[sc->map[n].provider_no].chunk_count);
1336                         return;
1337                 }
1338                 if (sc->map[n].flags & VIRSTOR_MAP_ALLOCATED)
1339                         sc->components[sc->map[n].provider_no].chunk_next++;
1340         }
1341
1342         sc->provider = g_new_providerf(sc->geom, "virstor/%s",
1343             sc->geom->name);
1344
1345         sc->provider->sectorsize = sc->sectorsize;
1346         sc->provider->mediasize = sc->virsize;
1347         g_error_provider(sc->provider, 0);
1348
1349         LOG_MSG(LVL_INFO, "%s activated", sc->provider->name);
1350         LOG_MSG(LVL_DEBUG, "%s starting with current component %u, starting "
1351             "chunk %u", sc->provider->name, sc->curr_component,
1352             sc->components[sc->curr_component].chunk_next);
1353 }
1354
1355 /*
1356  * Returns count of active providers in this geom instance
1357  */
1358 static u_int
1359 virstor_valid_components(struct g_virstor_softc *sc)
1360 {
1361         unsigned int nc, i;
1362
1363         nc = 0;
1364         KASSERT(sc != NULL, ("%s: softc is NULL", __func__));
1365         KASSERT(sc->components != NULL, ("%s: sc->components is NULL", __func__));
1366         for (i = 0; i < sc->n_components; i++)
1367                 if (sc->components[i].gcons != NULL)
1368                         nc++;
1369         return (nc);
1370 }
1371
1372 /*
1373  * Called when the consumer gets orphaned (?)
1374  */
1375 static void
1376 g_virstor_orphan(struct g_consumer *cp)
1377 {
1378         struct g_virstor_softc *sc;
1379         struct g_virstor_component *comp;
1380         struct g_geom *gp;
1381
1382         g_topology_assert();
1383         gp = cp->geom;
1384         sc = gp->softc;
1385         if (sc == NULL)
1386                 return;
1387
1388         comp = cp->private;
1389         KASSERT(comp != NULL, ("%s: No component in private part of consumer",
1390             __func__));
1391         remove_component(sc, comp, FALSE);
1392         if (LIST_EMPTY(&gp->consumer))
1393                 virstor_geom_destroy(sc, TRUE, FALSE);
1394 }
1395
1396 /*
1397  * Called to notify geom when it's been opened, and for what intent
1398  */
1399 static int
1400 g_virstor_access(struct g_provider *pp, int dr, int dw, int de)
1401 {
1402         struct g_consumer *c, *c2, *tmp;
1403         struct g_virstor_softc *sc;
1404         struct g_geom *gp;
1405         int error;
1406
1407         KASSERT(pp != NULL, ("%s: NULL provider", __func__));
1408         gp = pp->geom;
1409         KASSERT(gp != NULL, ("%s: NULL geom", __func__));
1410         sc = gp->softc;
1411
1412         /* Grab an exclusive bit to propagate on our consumers on first open */
1413         if (pp->acr == 0 && pp->acw == 0 && pp->ace == 0)
1414                 de++;
1415         /* ... drop it on close */
1416         if (pp->acr + dr == 0 && pp->acw + dw == 0 && pp->ace + de == 0) {
1417                 de--;
1418                 if (sc != NULL)
1419                         update_metadata(sc);
1420         }
1421
1422         error = ENXIO;
1423         LIST_FOREACH_SAFE(c, &gp->consumer, consumer, tmp) {
1424                 error = g_access(c, dr, dw, de);
1425                 if (error != 0)
1426                         goto fail;
1427                 if (c->acr == 0 && c->acw == 0 && c->ace == 0 &&
1428                     c->flags & G_CF_ORPHAN) {
1429                         g_detach(c);
1430                         g_destroy_consumer(c);
1431                 }
1432         }
1433
1434         if (sc != NULL && LIST_EMPTY(&gp->consumer))
1435                 virstor_geom_destroy(sc, TRUE, FALSE);
1436
1437         return (error);
1438
1439 fail:
1440         /* Backout earlier changes */
1441         LIST_FOREACH(c2, &gp->consumer, consumer) {
1442                 if (c2 == c)
1443                         break;
1444                 g_access(c2, -dr, -dw, -de);
1445         }
1446         return (error);
1447 }
1448
1449 /*
1450  * Generate XML dump of current state
1451  */
1452 static void
1453 g_virstor_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp,
1454     struct g_consumer *cp, struct g_provider *pp)
1455 {
1456         struct g_virstor_softc *sc;
1457
1458         g_topology_assert();
1459         sc = gp->softc;
1460
1461         if (sc == NULL || pp != NULL)
1462                 return;
1463
1464         if (cp != NULL) {
1465                 /* For each component */
1466                 struct g_virstor_component *comp;
1467
1468                 comp = cp->private;
1469                 if (comp == NULL)
1470                         return;
1471                 sbuf_printf(sb, "%s<ComponentIndex>%u</ComponentIndex>\n",
1472                     indent, comp->index);
1473                 sbuf_printf(sb, "%s<ChunkCount>%u</ChunkCount>\n",
1474                     indent, comp->chunk_count);
1475                 sbuf_printf(sb, "%s<ChunksUsed>%u</ChunksUsed>\n",
1476                     indent, comp->chunk_next);
1477                 sbuf_printf(sb, "%s<ChunksReserved>%u</ChunksReserved>\n",
1478                     indent, comp->chunk_reserved);
1479                 sbuf_printf(sb, "%s<StorageFree>%u%%</StorageFree>\n",
1480                     indent,
1481                     comp->chunk_next > 0 ? 100 -
1482                     ((comp->chunk_next + comp->chunk_reserved) * 100) /
1483                     comp->chunk_count : 100);
1484         } else {
1485                 /* For the whole thing */
1486                 u_int count, used, i;
1487                 off_t size;
1488
1489                 count = used = size = 0;
1490                 for (i = 0; i < sc->n_components; i++) {
1491                         if (sc->components[i].gcons != NULL) {
1492                                 count += sc->components[i].chunk_count;
1493                                 used += sc->components[i].chunk_next +
1494                                     sc->components[i].chunk_reserved;
1495                                 size += sc->components[i].gcons->
1496                                     provider->mediasize;
1497                         }
1498                 }
1499
1500                 sbuf_printf(sb, "%s<Status>"
1501                     "Components=%u, Online=%u</Status>\n", indent,
1502                     sc->n_components, virstor_valid_components(sc));
1503                 sbuf_printf(sb, "%s<State>%u%% physical free</State>\n",
1504                     indent, 100-(used * 100) / count);
1505                 sbuf_printf(sb, "%s<ChunkSize>%zu</ChunkSize>\n", indent,
1506                     sc->chunk_size);
1507                 sbuf_printf(sb, "%s<PhysicalFree>%u%%</PhysicalFree>\n",
1508                     indent, used > 0 ? 100 - (used * 100) / count : 100);
1509                 sbuf_printf(sb, "%s<ChunkPhysicalCount>%u</ChunkPhysicalCount>\n",
1510                     indent, count);
1511                 sbuf_printf(sb, "%s<ChunkVirtualCount>%zu</ChunkVirtualCount>\n",
1512                     indent, sc->chunk_count);
1513                 sbuf_printf(sb, "%s<PhysicalBacking>%zu%%</PhysicalBacking>\n",
1514                     indent,
1515                     (count * 100) / sc->chunk_count);
1516                 sbuf_printf(sb, "%s<PhysicalBackingSize>%jd</PhysicalBackingSize>\n",
1517                     indent, size);
1518                 sbuf_printf(sb, "%s<VirtualSize>%jd</VirtualSize>\n", indent,
1519                     sc->virsize);
1520         }
1521 }
1522
1523 /*
1524  * GEOM .done handler
1525  * Can't use standard handler because one requested IO may
1526  * fork into additional data IOs
1527  */
1528 static void
1529 g_virstor_done(struct bio *b)
1530 {
1531         struct g_virstor_softc *sc;
1532         struct bio *parent_b;
1533
1534         parent_b = b->bio_parent;
1535         sc = parent_b->bio_to->geom->softc;
1536
1537         if (b->bio_error != 0) {
1538                 LOG_MSG(LVL_ERROR, "Error %d for offset=%ju, length=%ju, %s",
1539                     b->bio_error, b->bio_offset, b->bio_length,
1540                     b->bio_to->name);
1541                 if (parent_b->bio_error == 0)
1542                         parent_b->bio_error = b->bio_error;
1543         }
1544
1545         parent_b->bio_inbed++;
1546         parent_b->bio_completed += b->bio_completed;
1547
1548         if (parent_b->bio_children == parent_b->bio_inbed) {
1549                 parent_b->bio_completed = parent_b->bio_length;
1550                 g_io_deliver(parent_b, parent_b->bio_error);
1551         }
1552         g_destroy_bio(b);
1553 }
1554
1555 /*
1556  * I/O starts here
1557  * Called in g_down thread
1558  */
1559 static void
1560 g_virstor_start(struct bio *b)
1561 {
1562         struct g_virstor_softc *sc;
1563         struct g_virstor_component *comp;
1564         struct bio *cb;
1565         struct g_provider *pp;
1566         char *addr;
1567         off_t offset, length;
1568         struct bio_queue_head bq;
1569         size_t chunk_size;      /* cached for convenience */
1570         u_int count;
1571
1572         pp = b->bio_to;
1573         sc = pp->geom->softc;
1574         KASSERT(sc != NULL, ("%s: no softc (error=%d, device=%s)", __func__,
1575             b->bio_to->error, b->bio_to->name));
1576
1577         LOG_REQ(LVL_MOREDEBUG, b, "%s", __func__);
1578
1579         switch (b->bio_cmd) {
1580         case BIO_READ:
1581         case BIO_WRITE:
1582         case BIO_DELETE:
1583                 break;
1584         default:
1585                 g_io_deliver(b, EOPNOTSUPP);
1586                 return;
1587         }
1588
1589         LOG_MSG(LVL_DEBUG2, "BIO arrived, size=%ju", b->bio_length);
1590         bioq_init(&bq);
1591
1592         chunk_size = sc->chunk_size;
1593         addr = b->bio_data;
1594         offset = b->bio_offset; /* virtual offset and length */
1595         length = b->bio_length;
1596
1597         while (length > 0) {
1598                 size_t chunk_index, in_chunk_offset, in_chunk_length;
1599                 struct virstor_map_entry *me;
1600
1601                 chunk_index = offset / chunk_size; /* round downwards */
1602                 in_chunk_offset = offset % chunk_size;
1603                 in_chunk_length = min(length, chunk_size - in_chunk_offset);
1604                 LOG_MSG(LVL_DEBUG, "Mapped %s(%ju, %ju) to (%zu,%zu,%zu)",
1605                     b->bio_cmd == BIO_READ ? "R" : "W",
1606                     offset, length,
1607                     chunk_index, in_chunk_offset, in_chunk_length);
1608                 me = &sc->map[chunk_index];
1609
1610                 if (b->bio_cmd == BIO_READ || b->bio_cmd == BIO_DELETE) {
1611                         if ((me->flags & VIRSTOR_MAP_ALLOCATED) == 0) {
1612                                 /* Reads from unallocated chunks return zeroed
1613                                  * buffers */
1614                                 if (b->bio_cmd == BIO_READ)
1615                                         bzero(addr, in_chunk_length);
1616                         } else {
1617                                 comp = &sc->components[me->provider_no];
1618
1619                                 cb = g_clone_bio(b);
1620                                 if (cb == NULL) {
1621                                         bioq_dismantle(&bq);
1622                                         if (b->bio_error == 0)
1623                                                 b->bio_error = ENOMEM;
1624                                         g_io_deliver(b, b->bio_error);
1625                                         return;
1626                                 }
1627                                 cb->bio_to = comp->gcons->provider;
1628                                 cb->bio_done = g_virstor_done;
1629                                 cb->bio_offset =
1630                                     (off_t)me->provider_chunk * (off_t)chunk_size
1631                                     + in_chunk_offset;
1632                                 cb->bio_length = in_chunk_length;
1633                                 cb->bio_data = addr;
1634                                 cb->bio_caller1 = comp;
1635                                 bioq_disksort(&bq, cb);
1636                         }
1637                 } else { /* handle BIO_WRITE */
1638                         KASSERT(b->bio_cmd == BIO_WRITE,
1639                             ("%s: Unknown command %d", __func__,
1640                             b->bio_cmd));
1641
1642                         if ((me->flags & VIRSTOR_MAP_ALLOCATED) == 0) {
1643                                 /* We have a virtual chunk, represented by
1644                                  * the "me" entry, but it's not yet allocated
1645                                  * (tied to) a physical chunk. So do it now. */
1646                                 struct virstor_map_entry *data_me;
1647                                 u_int phys_chunk, comp_no;
1648                                 off_t s_offset;
1649                                 int error;
1650
1651                                 error = allocate_chunk(sc, &comp, &comp_no,
1652                                     &phys_chunk);
1653                                 if (error != 0) {
1654                                         /* We cannot allocate a physical chunk
1655                                          * to satisfy this request, so we'll
1656                                          * delay it to when we can...
1657                                          * XXX: this will prevent the fs from
1658                                          * being umounted! */
1659                                         struct g_virstor_bio_q *biq;
1660                                         biq = malloc(sizeof *biq, M_GVIRSTOR,
1661                                             M_NOWAIT);
1662                                         if (biq == NULL) {
1663                                                 bioq_dismantle(&bq);
1664                                                 if (b->bio_error == 0)
1665                                                         b->bio_error = ENOMEM;
1666                                                 g_io_deliver(b, b->bio_error);
1667                                                 return;
1668                                         }
1669                                         biq->bio = b;
1670                                         mtx_lock(&sc->delayed_bio_q_mtx);
1671                                         STAILQ_INSERT_TAIL(&sc->delayed_bio_q,
1672                                             biq, linkage);
1673                                         mtx_unlock(&sc->delayed_bio_q_mtx);
1674                                         LOG_MSG(LVL_WARNING, "Delaying BIO "
1675                                             "(size=%ju) until free physical "
1676                                             "space can be found on %s",
1677                                             b->bio_length,
1678                                             sc->provider->name);
1679                                         return;
1680                                 }
1681                                 LOG_MSG(LVL_DEBUG, "Allocated chunk %u on %s "
1682                                     "for %s",
1683                                     phys_chunk,
1684                                     comp->gcons->provider->name,
1685                                     sc->provider->name);
1686
1687                                 me->provider_no = comp_no;
1688                                 me->provider_chunk = phys_chunk;
1689                                 me->flags |= VIRSTOR_MAP_ALLOCATED;
1690
1691                                 cb = g_clone_bio(b);
1692                                 if (cb == NULL) {
1693                                         me->flags &= ~VIRSTOR_MAP_ALLOCATED;
1694                                         me->provider_no = 0;
1695                                         me->provider_chunk = 0;
1696                                         bioq_dismantle(&bq);
1697                                         if (b->bio_error == 0)
1698                                                 b->bio_error = ENOMEM;
1699                                         g_io_deliver(b, b->bio_error);
1700                                         return;
1701                                 }
1702
1703                                 /* The allocation table is stored continuously
1704                                  * at the start of the drive. We need to
1705                                  * calculate the offset of the sector that holds
1706                                  * this map entry both on the drive and in the
1707                                  * map array.
1708                                  * sc_offset will end up pointing to the drive
1709                                  * sector. */
1710                                 s_offset = chunk_index * sizeof *me;
1711                                 s_offset = rounddown(s_offset, sc->sectorsize);
1712
1713                                 /* data_me points to map entry sector
1714                                  * in memory (analogous to offset) */
1715                                 data_me = &sc->map[rounddown(chunk_index,
1716                                     sc->me_per_sector)];
1717
1718                                 /* Commit sector with map entry to storage */
1719                                 cb->bio_to = sc->components[0].gcons->provider;
1720                                 cb->bio_done = g_virstor_done;
1721                                 cb->bio_offset = s_offset;
1722                                 cb->bio_data = (char *)data_me;
1723                                 cb->bio_length = sc->sectorsize;
1724                                 cb->bio_caller1 = &sc->components[0];
1725                                 bioq_disksort(&bq, cb);
1726                         }
1727
1728                         comp = &sc->components[me->provider_no];
1729                         cb = g_clone_bio(b);
1730                         if (cb == NULL) {
1731                                 bioq_dismantle(&bq);
1732                                 if (b->bio_error == 0)
1733                                         b->bio_error = ENOMEM;
1734                                 g_io_deliver(b, b->bio_error);
1735                                 return;
1736                         }
1737                         /* Finally, handle the data */
1738                         cb->bio_to = comp->gcons->provider;
1739                         cb->bio_done = g_virstor_done;
1740                         cb->bio_offset = (off_t)me->provider_chunk*(off_t)chunk_size +
1741                             in_chunk_offset;
1742                         cb->bio_length = in_chunk_length;
1743                         cb->bio_data = addr;
1744                         cb->bio_caller1 = comp;
1745                         bioq_disksort(&bq, cb);
1746                 }
1747                 addr += in_chunk_length;
1748                 length -= in_chunk_length;
1749                 offset += in_chunk_length;
1750         }
1751
1752         /* Fire off bio's here */
1753         count = 0;
1754         for (cb = bioq_first(&bq); cb != NULL; cb = bioq_first(&bq)) {
1755                 bioq_remove(&bq, cb);
1756                 LOG_REQ(LVL_MOREDEBUG, cb, "Firing request");
1757                 comp = cb->bio_caller1;
1758                 cb->bio_caller1 = NULL;
1759                 LOG_MSG(LVL_DEBUG, " firing bio, offset=%ju, length=%ju",
1760                     cb->bio_offset, cb->bio_length);
1761                 g_io_request(cb, comp->gcons);
1762                 count++;
1763         }
1764         if (count == 0) { /* We handled everything locally */
1765                 b->bio_completed = b->bio_length;
1766                 g_io_deliver(b, 0);
1767         }
1768
1769 }
1770
1771 /*
1772  * Allocate a chunk from a physical provider. Returns physical component,
1773  * chunk index relative to the component and the component's index.
1774  */
1775 static int
1776 allocate_chunk(struct g_virstor_softc *sc, struct g_virstor_component **comp,
1777     u_int *comp_no_p, u_int *chunk)
1778 {
1779         u_int comp_no;
1780
1781         KASSERT(sc->curr_component < sc->n_components,
1782             ("%s: Invalid curr_component: %u",  __func__, sc->curr_component));
1783
1784         comp_no = sc->curr_component;
1785         *comp = &sc->components[comp_no];
1786         dump_component(*comp);
1787         if ((*comp)->chunk_next >= (*comp)->chunk_count) {
1788                 /* This component is full. Allocate next component */
1789                 if (comp_no >= sc->n_components-1) {
1790                         LOG_MSG(LVL_ERROR, "All physical space allocated for %s",
1791                             sc->geom->name);
1792                         return (-1);
1793                 }
1794                 (*comp)->flags &= ~VIRSTOR_PROVIDER_CURRENT;
1795                 sc->curr_component = ++comp_no;
1796
1797                 *comp = &sc->components[comp_no];
1798                 if (comp_no >= sc->n_components - g_virstor_component_watermark-1)
1799                         LOG_MSG(LVL_WARNING, "Device %s running out of components "
1800                             "(switching to %u/%u: %s)", sc->geom->name,
1801                             comp_no+1, sc->n_components,
1802                             (*comp)->gcons->provider->name);
1803                 /* Take care not to overwrite reserved chunks */
1804                 if ( (*comp)->chunk_reserved > 0 &&
1805                     (*comp)->chunk_next < (*comp)->chunk_reserved)
1806                         (*comp)->chunk_next = (*comp)->chunk_reserved;
1807
1808                 (*comp)->flags |=
1809                     VIRSTOR_PROVIDER_ALLOCATED | VIRSTOR_PROVIDER_CURRENT;
1810                 dump_component(*comp);
1811                 *comp_no_p = comp_no;
1812                 *chunk = (*comp)->chunk_next++;
1813         } else {
1814                 *comp_no_p = comp_no;
1815                 *chunk = (*comp)->chunk_next++;
1816         }
1817         return (0);
1818 }
1819
1820 /* Dump a component */
1821 static void
1822 dump_component(struct g_virstor_component *comp)
1823 {
1824
1825         if (g_virstor_debug < LVL_DEBUG2)
1826                 return;
1827         printf("Component %d: %s\n", comp->index, comp->gcons->provider->name);
1828         printf("  chunk_count: %u\n", comp->chunk_count);
1829         printf("   chunk_next: %u\n", comp->chunk_next);
1830         printf("        flags: %u\n", comp->flags);
1831 }
1832
1833 #if 0
1834 /* Dump a map entry */
1835 static void
1836 dump_me(struct virstor_map_entry *me, unsigned int nr)
1837 {
1838         if (g_virstor_debug < LVL_DEBUG)
1839                 return;
1840         printf("VIRT. CHUNK #%d: ", nr);
1841         if ((me->flags & VIRSTOR_MAP_ALLOCATED) == 0)
1842                 printf("(unallocated)\n");
1843         else
1844                 printf("allocated at provider %u, provider_chunk %u\n",
1845                     me->provider_no, me->provider_chunk);
1846 }
1847 #endif
1848
1849 /*
1850  * Dismantle bio_queue and destroy its components
1851  */
1852 static void
1853 bioq_dismantle(struct bio_queue_head *bq)
1854 {
1855         struct bio *b;
1856
1857         for (b = bioq_first(bq); b != NULL; b = bioq_first(bq)) {
1858                 bioq_remove(bq, b);
1859                 g_destroy_bio(b);
1860         }
1861 }
1862
1863 /*
1864  * The function that shouldn't be called.
1865  * When this is called, the stack is already garbled because of
1866  * argument mismatch. There's nothing to do now but panic, which is
1867  * accidentally the whole purpose of this function.
1868  * Motivation: to guard from accidentally calling geom methods when
1869  * they shouldn't be called. (see g_..._taste)
1870  */
1871 static void
1872 invalid_call(void)
1873 {
1874         panic("invalid_call() has just been called. Something's fishy here.");
1875 }
1876
1877 DECLARE_GEOM_CLASS(g_virstor_class, g_virstor); /* Let there be light */
1878 MODULE_VERSION(geom_virstor, 0);