sys/geom/virstor/g_virstor.c

   1 /*-
   2  * Copyright (c) 2006-2007 Ivan Voras <ivoras@freebsd.org>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  */
  26
  27 /* Implementation notes:
  28  * - "Components" are wrappers around providers that make up the
  29  *   virtual storage (i.e. a virstor has "physical" components)
  30  */
  31
  32 #include <sys/cdefs.h>
  33 __FBSDID("$FreeBSD$");
  34
  35 #include <sys/param.h>
  36 #include <sys/systm.h>
  37 #include <sys/kernel.h>
  38 #include <sys/module.h>
  39 #include <sys/lock.h>
  40 #include <sys/mutex.h>
  41 #include <sys/sx.h>
  42 #include <sys/bio.h>
  43 #include <sys/sbuf.h>
  44 #include <sys/sysctl.h>
  45 #include <sys/malloc.h>
  46 #include <sys/time.h>
  47 #include <sys/proc.h>
  48 #include <sys/kthread.h>
  49 #include <sys/mutex.h>
  50 #include <vm/uma.h>
  51 #include <geom/geom.h>
  52
  53 #include <geom/virstor/g_virstor.h>
  54 #include <geom/virstor/g_virstor_md.h>
  55
  56 FEATURE(g_virstor, "GEOM virtual storage support");
  57
  58 /* Declare malloc(9) label */
  59 static MALLOC_DEFINE(M_GVIRSTOR, "gvirstor", "GEOM_VIRSTOR Data");
  60
  61 /* GEOM class methods */
  62 static g_init_t g_virstor_init;
  63 static g_fini_t g_virstor_fini;
  64 static g_taste_t g_virstor_taste;
  65 static g_ctl_req_t g_virstor_config;
  66 static g_ctl_destroy_geom_t g_virstor_destroy_geom;
  67
  68 /* Declare & initialize class structure ("geom class") */
  69 struct g_class g_virstor_class = {
  70         .name =         G_VIRSTOR_CLASS_NAME,
  71         .version =      G_VERSION,
  72         .init =         g_virstor_init,
  73         .fini =         g_virstor_fini,
  74         .taste =        g_virstor_taste,
  75         .ctlreq =       g_virstor_config,
  76         .destroy_geom = g_virstor_destroy_geom
  77         /* The .dumpconf and the rest are only usable for a geom instance, so
  78          * they will be set when such instance is created. */
  79 };
  80
  81 /* Declare sysctl's and loader tunables */
  82 SYSCTL_DECL(_kern_geom);
  83 static SYSCTL_NODE(_kern_geom, OID_AUTO, virstor, CTLFLAG_RW, 0,
  84     "GEOM_GVIRSTOR information");
  85
  86 static u_int g_virstor_debug = 2; /* XXX: lower to 2 when released to public */
  87 TUNABLE_INT("kern.geom.virstor.debug", &g_virstor_debug);
  88 SYSCTL_UINT(_kern_geom_virstor, OID_AUTO, debug, CTLFLAG_RW, &g_virstor_debug,
  89     0, "Debug level (2=production, 5=normal, 15=excessive)");
  90
  91 static u_int g_virstor_chunk_watermark = 100;
  92 TUNABLE_INT("kern.geom.virstor.chunk_watermark", &g_virstor_chunk_watermark);
  93 SYSCTL_UINT(_kern_geom_virstor, OID_AUTO, chunk_watermark, CTLFLAG_RW,
  94     &g_virstor_chunk_watermark, 0,
  95     "Minimum number of free chunks before issuing administrative warning");
  96
  97 static u_int g_virstor_component_watermark = 1;
  98 TUNABLE_INT("kern.geom.virstor.component_watermark",
  99     &g_virstor_component_watermark);
 100 SYSCTL_UINT(_kern_geom_virstor, OID_AUTO, component_watermark, CTLFLAG_RW,
 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                 sprintf(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                 const char *prov_name;
 317                 struct g_provider *pp;
 318                 struct g_consumer *cp;
 319                 u_int nc;
 320                 u_int j;
 321
 322                 snprintf(aname, sizeof aname, "arg%d", i);
 323                 prov_name = gctl_get_asciiparam(req, aname);
 324                 if (prov_name == NULL) {
 325                         gctl_error(req, "Error fetching argument '%s'", aname);
 326                         g_topology_unlock();
 327                         return;
 328                 }
 329                 if (strncmp(prov_name, _PATH_DEV, sizeof(_PATH_DEV) - 1) == 0)
 330                         prov_name += sizeof(_PATH_DEV) - 1;
 331
 332                 pp = g_provider_by_name(prov_name);
 333                 if (pp == NULL) {
 334                         /* This is the most common error so be verbose about it */
 335                         if (added != 0) {
 336                                 gctl_error(req, "Invalid provider: '%s' (added"
 337                                     " %u components)", prov_name, added);
 338                                 update_metadata(sc);
 339                         } else {
 340                                 gctl_error(req, "Invalid provider: '%s'",
 341                                     prov_name);
 342                         }
 343                         g_topology_unlock();
 344                         return;
 345                 }
 346                 cp = g_new_consumer(sc->geom);
 347                 if (cp == NULL) {
 348                         gctl_error(req, "Cannot create consumer");
 349                         g_topology_unlock();
 350                         return;
 351                 }
 352                 error = g_attach(cp, pp);
 353                 if (error != 0) {
 354                         gctl_error(req, "Cannot attach a consumer to %s",
 355                             pp->name);
 356                         g_destroy_consumer(cp);
 357                         g_topology_unlock();
 358                         return;
 359                 }
 360                 if (fcp->acr != 0 || fcp->acw != 0 || fcp->ace != 0) {
 361                         error = g_access(cp, fcp->acr, fcp->acw, fcp->ace);
 362                         if (error != 0) {
 363                                 gctl_error(req, "Access request failed for %s",
 364                                     pp->name);
 365                                 g_destroy_consumer(cp);
 366                                 g_topology_unlock();
 367                                 return;
 368                         }
 369                 }
 370                 if (fcp->provider->sectorsize != pp->sectorsize) {
 371                         gctl_error(req, "Sector size doesn't fit for %s",
 372                             pp->name);
 373                         g_destroy_consumer(cp);
 374                         g_topology_unlock();
 375                         return;
 376                 }
 377                 for (j = 0; j < sc->n_components; j++) {
 378                         if (strcmp(sc->components[j].gcons->provider->name,
 379                             pp->name) == 0) {
 380                                 gctl_error(req, "Component %s already in %s",
 381                                     pp->name, sc->geom->name);
 382                                 g_destroy_consumer(cp);
 383                                 g_topology_unlock();
 384                                 return;
 385                         }
 386                 }
 387                 sc->components = realloc(sc->components,
 388                     sizeof(*sc->components) * (sc->n_components + 1),
 389                     M_GVIRSTOR, M_WAITOK);
 390
 391                 nc = sc->n_components;
 392                 sc->components[nc].gcons = cp;
 393                 sc->components[nc].sc = sc;
 394                 sc->components[nc].index = nc;
 395                 sc->components[nc].chunk_count = cp->provider->mediasize /
 396                     sc->chunk_size;
 397                 sc->components[nc].chunk_next = 0;
 398                 sc->components[nc].chunk_reserved = 0;
 399
 400                 if (sc->components[nc].chunk_count < 4) {
 401                         gctl_error(req, "Provider too small: %s",
 402                             cp->provider->name);
 403                         g_destroy_consumer(cp);
 404                         g_topology_unlock();
 405                         return;
 406                 }
 407                 fill_metadata(sc, &md, nc, *hardcode);
 408                 write_metadata(cp, &md);
 409                 /* The new component becomes visible when n_components is
 410                  * incremented */
 411                 sc->n_components++;
 412                 added++;
 413
 414         }
 415         /* This call to update_metadata() is critical. In case there's a
 416          * power failure in the middle of it and some components are updated
 417          * while others are not, there will be trouble on next .taste() iff
 418          * a non-updated component is detected first */
 419         update_metadata(sc);
 420         g_topology_unlock();
 421         LOG_MSG(LVL_INFO, "Added %d component(s) to %s", added,
 422             sc->geom->name);
 423         /* Fire off BIOs previously queued because there wasn't any
 424          * physical space left. If the BIOs still can't be satisfied
 425          * they will again be added to the end of the queue (during
 426          * which the mutex will be recursed) */
 427         bq = malloc(sizeof(*bq), M_GVIRSTOR, M_WAITOK);
 428         bq->bio = NULL;
 429         mtx_lock(&sc->delayed_bio_q_mtx);
 430         /* First, insert a sentinel to the queue end, so we don't
 431          * end up in an infinite loop if there's still no free
 432          * space available. */
 433         STAILQ_INSERT_TAIL(&sc->delayed_bio_q, bq, linkage);
 434         while (!STAILQ_EMPTY(&sc->delayed_bio_q)) {
 435                 bq = STAILQ_FIRST(&sc->delayed_bio_q);
 436                 if (bq->bio != NULL) {
 437                         g_virstor_start(bq->bio);
 438                         STAILQ_REMOVE_HEAD(&sc->delayed_bio_q, linkage);
 439                         free(bq, M_GVIRSTOR);
 440                 } else {
 441                         STAILQ_REMOVE_HEAD(&sc->delayed_bio_q, linkage);
 442                         free(bq, M_GVIRSTOR);
 443                         break;
 444                 }
 445         }
 446         mtx_unlock(&sc->delayed_bio_q_mtx);
 447
 448 }
 449
 450 /*
 451  * Find a geom handled by the class
 452  */
 453 static struct g_virstor_softc *
 454 virstor_find_geom(const struct g_class *cp, const char *name)
 455 {
 456         struct g_geom *gp;
 457
 458         LIST_FOREACH(gp, &cp->geom, geom) {
 459                 if (strcmp(name, gp->name) == 0)
 460                         return (gp->softc);
 461         }
 462         return (NULL);
 463 }
 464
 465 /*
 466  * Update metadata on all components to reflect the current state
 467  * of these fields:
 468  *    - chunk_next
 469  *    - flags
 470  *    - md_count
 471  * Expects things to be set up so write_metadata() can work, i.e.
 472  * the topology lock must be held.
 473  */
 474 static void
 475 update_metadata(struct g_virstor_softc *sc)
 476 {
 477         struct g_virstor_metadata md;
 478         u_int n;
 479
 480         if (virstor_valid_components(sc) != sc->n_components)
 481                 return; /* Incomplete device */
 482         LOG_MSG(LVL_DEBUG, "Updating metadata on components for %s",
 483             sc->geom->name);
 484         /* Update metadata on components */
 485         g_trace(G_T_TOPOLOGY, "%s(%s, %s)", __func__,
 486             sc->geom->class->name, sc->geom->name);
 487         g_topology_assert();
 488         for (n = 0; n < sc->n_components; n++) {
 489                 read_metadata(sc->components[n].gcons, &md);
 490                 md.chunk_next = sc->components[n].chunk_next;
 491                 md.flags = sc->components[n].flags;
 492                 md.md_count = sc->n_components;
 493                 write_metadata(sc->components[n].gcons, &md);
 494         }
 495 }
 496
 497 /*
 498  * Fills metadata (struct md) from information stored in softc and the nc'th
 499  * component of virstor
 500  */
 501 static void
 502 fill_metadata(struct g_virstor_softc *sc, struct g_virstor_metadata *md,
 503     u_int nc, u_int hardcode)
 504 {
 505         struct g_virstor_component *c;
 506
 507         bzero(md, sizeof *md);
 508         c = &sc->components[nc];
 509
 510         strncpy(md->md_magic, G_VIRSTOR_MAGIC, sizeof md->md_magic);
 511         md->md_version = G_VIRSTOR_VERSION;
 512         strncpy(md->md_name, sc->geom->name, sizeof md->md_name);
 513         md->md_id = sc->id;
 514         md->md_virsize = sc->virsize;
 515         md->md_chunk_size = sc->chunk_size;
 516         md->md_count = sc->n_components;
 517
 518         if (hardcode) {
 519                 strncpy(md->provider, c->gcons->provider->name,
 520                     sizeof md->provider);
 521         }
 522         md->no = nc;
 523         md->provsize = c->gcons->provider->mediasize;
 524         md->chunk_count = c->chunk_count;
 525         md->chunk_next = c->chunk_next;
 526         md->chunk_reserved = c->chunk_reserved;
 527         md->flags = c->flags;
 528 }
 529
 530 /*
 531  * Remove a component from virstor device.
 532  * Can only be done if the component is unallocated.
 533  */
 534 static void
 535 virstor_ctl_remove(struct gctl_req *req, struct g_class *cp)
 536 {
 537         /* As this is executed in parallel to I/O, operations on virstor
 538          * structures must be as atomic as possible. */
 539         struct g_virstor_softc *sc;
 540         int *nargs;
 541         const char *geom_name;
 542         u_int removed;
 543         int i;
 544
 545         nargs = gctl_get_paraml(req, "nargs", sizeof(*nargs));
 546         if (nargs == NULL) {
 547                 gctl_error(req, "Error fetching argument '%s'", "nargs");
 548                 return;
 549         }
 550         if (*nargs < 2) {
 551                 gctl_error(req, "Invalid number of arguments");
 552                 return;
 553         }
 554         /* Find "our" geom */
 555         geom_name = gctl_get_asciiparam(req, "arg0");
 556         if (geom_name == NULL) {
 557                 gctl_error(req, "Error fetching argument '%s'",
 558                     "geom_name (arg0)");
 559                 return;
 560         }
 561         sc = virstor_find_geom(cp, geom_name);
 562         if (sc == NULL) {
 563                 gctl_error(req, "Don't know anything about '%s'", geom_name);
 564                 return;
 565         }
 566
 567         if (virstor_valid_components(sc) != sc->n_components) {
 568                 LOG_MSG(LVL_ERROR, "Cannot remove components from incomplete "
 569                     "virstor %s", sc->geom->name);
 570                 gctl_error(req, "Virstor %s is incomplete", sc->geom->name);
 571                 return;
 572         }
 573
 574         removed = 0;
 575         for (i = 1; i < *nargs; i++) {
 576                 char param[8];
 577                 const char *prov_name;
 578                 int j, found;
 579                 struct g_virstor_component *newcomp, *compbak;
 580
 581                 sprintf(param, "arg%d", i);
 582                 prov_name = gctl_get_asciiparam(req, param);
 583                 if (prov_name == NULL) {
 584                         gctl_error(req, "Error fetching argument '%s'", param);
 585                         return;
 586                 }
 587                 if (strncmp(prov_name, _PATH_DEV, sizeof(_PATH_DEV) - 1) == 0)
 588                         prov_name += sizeof(_PATH_DEV) - 1;
 589
 590                 found = -1;
 591                 for (j = 0; j < sc->n_components; j++) {
 592                         if (strcmp(sc->components[j].gcons->provider->name,
 593                             prov_name) == 0) {
 594                                 found = j;
 595                                 break;
 596                         }
 597                 }
 598                 if (found == -1) {
 599                         LOG_MSG(LVL_ERROR, "No %s component in %s",
 600                             prov_name, sc->geom->name);
 601                         continue;
 602                 }
 603
 604                 compbak = sc->components;
 605                 newcomp = malloc(sc->n_components * sizeof(*sc->components),
 606                     M_GVIRSTOR, M_WAITOK | M_ZERO);
 607                 bcopy(sc->components, newcomp, found * sizeof(*sc->components));
 608                 bcopy(&sc->components[found + 1], newcomp + found,
 609                     found * sizeof(*sc->components));
 610                 if ((sc->components[j].flags & VIRSTOR_PROVIDER_ALLOCATED) != 0) {
 611                         LOG_MSG(LVL_ERROR, "Allocated provider %s cannot be "
 612                             "removed from %s",
 613                             prov_name, sc->geom->name);
 614                         free(newcomp, M_GVIRSTOR);
 615                         /* We'll consider this non-fatal error */
 616                         continue;
 617                 }
 618                 /* Renumerate unallocated components */
 619                 for (j = 0; j < sc->n_components-1; j++) {
 620                         if ((sc->components[j].flags &
 621                             VIRSTOR_PROVIDER_ALLOCATED) == 0) {
 622                                 sc->components[j].index = j;
 623                         }
 624                 }
 625                 /* This is the critical section. If a component allocation
 626                  * event happens while both variables are not yet set,
 627                  * there will be trouble. Something will panic on encountering
 628                  * NULL sc->components[x].gcomp member.
 629                  * Luckily, component allocation happens very rarely and
 630                  * removing components is an abnormal action in any case. */
 631                 sc->components = newcomp;
 632                 sc->n_components--;
 633                 /* End critical section */
 634
 635                 g_topology_lock();
 636                 if (clear_metadata(&compbak[found]) != 0) {
 637                         LOG_MSG(LVL_WARNING, "Trouble ahead: cannot clear "
 638                             "metadata on %s", prov_name);
 639                 }
 640                 g_detach(compbak[found].gcons);
 641                 g_destroy_consumer(compbak[found].gcons);
 642                 g_topology_unlock();
 643
 644                 free(compbak, M_GVIRSTOR);
 645
 646                 removed++;
 647         }
 648
 649         /* This call to update_metadata() is critical. In case there's a
 650          * power failure in the middle of it and some components are updated
 651          * while others are not, there will be trouble on next .taste() iff
 652          * a non-updated component is detected first */
 653         g_topology_lock();
 654         update_metadata(sc);
 655         g_topology_unlock();
 656         LOG_MSG(LVL_INFO, "Removed %d component(s) from %s", removed,
 657             sc->geom->name);
 658 }
 659
 660 /*
 661  * Clear metadata sector on component
 662  */
 663 static int
 664 clear_metadata(struct g_virstor_component *comp)
 665 {
 666         char *buf;
 667         int error;
 668
 669         LOG_MSG(LVL_INFO, "Clearing metadata on %s",
 670             comp->gcons->provider->name);
 671         g_topology_assert();
 672         error = g_access(comp->gcons, 0, 1, 0);
 673         if (error != 0)
 674                 return (error);
 675         buf = malloc(comp->gcons->provider->sectorsize, M_GVIRSTOR,
 676             M_WAITOK | M_ZERO);
 677         error = g_write_data(comp->gcons,
 678             comp->gcons->provider->mediasize -
 679             comp->gcons->provider->sectorsize,
 680             buf,
 681             comp->gcons->provider->sectorsize);
 682         free(buf, M_GVIRSTOR);
 683         g_access(comp->gcons, 0, -1, 0);
 684         return (error);
 685 }
 686
 687 /*
 688  * Destroy geom forcibly.
 689  */
 690 static int
 691 g_virstor_destroy_geom(struct gctl_req *req __unused, struct g_class *mp,
 692     struct g_geom *gp)
 693 {
 694         struct g_virstor_softc *sc;
 695         int exitval;
 696
 697         sc = gp->softc;
 698         KASSERT(sc != NULL, ("%s: NULL sc", __func__));
 699
 700         exitval = 0;
 701         LOG_MSG(LVL_DEBUG, "%s called for %s, sc=%p", __func__, gp->name,
 702             gp->softc);
 703
 704         if (sc != NULL) {
 705 #ifdef INVARIANTS
 706                 char *buf;
 707                 int error;
 708                 off_t off;
 709                 int isclean, count;
 710                 int n;
 711
 712                 LOG_MSG(LVL_INFO, "INVARIANTS detected");
 713                 LOG_MSG(LVL_INFO, "Verifying allocation "
 714                     "table for %s", sc->geom->name);
 715                 count = 0;
 716                 for (n = 0; n < sc->chunk_count; n++) {
 717                         if (sc->map[n].flags || VIRSTOR_MAP_ALLOCATED != 0)
 718                                 count++;
 719                 }
 720                 LOG_MSG(LVL_INFO, "Device %s has %d allocated chunks",
 721                     sc->geom->name, count);
 722                 n = off = count = 0;
 723                 isclean = 1;
 724                 if (virstor_valid_components(sc) != sc->n_components) {
 725                         /* This is a incomplete virstor device (not all
 726                          * components have been found) */
 727                         LOG_MSG(LVL_ERROR, "Device %s is incomplete",
 728                             sc->geom->name);
 729                         goto bailout;
 730                 }
 731                 error = g_access(sc->components[0].gcons, 1, 0, 0);
 732                 KASSERT(error == 0, ("%s: g_access failed (%d)", __func__,
 733                     error));
 734                 /* Compare the whole on-disk allocation table with what's
 735                  * currently in memory */
 736                 while (n < sc->chunk_count) {
 737                         buf = g_read_data(sc->components[0].gcons, off,
 738                             sc->sectorsize, &error);
 739                         KASSERT(buf != NULL, ("g_read_data returned NULL (%d) "
 740                             "for read at %jd", error, off));
 741                         if (bcmp(buf, &sc->map[n], sc->sectorsize) != 0) {
 742                                 LOG_MSG(LVL_ERROR, "ERROR in allocation table, "
 743                                     "entry %d, offset %jd", n, off);
 744                                 isclean = 0;
 745                                 count++;
 746                         }
 747                         n += sc->me_per_sector;
 748                         off += sc->sectorsize;
 749                         g_free(buf);
 750                 }
 751                 error = g_access(sc->components[0].gcons, -1, 0, 0);
 752                 KASSERT(error == 0, ("%s: g_access failed (%d) on exit",
 753                     __func__, error));
 754                 if (isclean != 1) {
 755                         LOG_MSG(LVL_ERROR, "ALLOCATION TABLE CORRUPTED FOR %s "
 756                             "(%d sectors don't match, max %zu allocations)",
 757                             sc->geom->name, count,
 758                             count * sc->me_per_sector);
 759                 } else {
 760                         LOG_MSG(LVL_INFO, "Allocation table ok for %s",
 761                             sc->geom->name);
 762                 }
 763 bailout:
 764 #endif
 765                 update_metadata(sc);
 766                 virstor_geom_destroy(sc, FALSE, FALSE);
 767                 exitval = EAGAIN;
 768         } else
 769                 exitval = 0;
 770         return (exitval);
 771 }
 772
 773 /*
 774  * Taste event (per-class callback)
 775  * Examines a provider and creates geom instances if needed
 776  */
 777 static struct g_geom *
 778 g_virstor_taste(struct g_class *mp, struct g_provider *pp, int flags)
 779 {
 780         struct g_virstor_metadata md;
 781         struct g_geom *gp;
 782         struct g_consumer *cp;
 783         struct g_virstor_softc *sc;
 784         int error;
 785
 786         g_trace(G_T_TOPOLOGY, "%s(%s, %s)", __func__, mp->name, pp->name);
 787         g_topology_assert();
 788         LOG_MSG(LVL_DEBUG, "Tasting %s", pp->name);
 789
 790         /* We need a dummy geom to attach a consumer to the given provider */
 791         gp = g_new_geomf(mp, "virstor:taste.helper");
 792         gp->start = (void *)invalid_call;       /* XXX: hacked up so the        */
 793         gp->access = (void *)invalid_call;      /* compiler doesn't complain.   */
 794         gp->orphan = (void *)invalid_call;      /* I really want these to fail. */
 795
 796         cp = g_new_consumer(gp);
 797         g_attach(cp, pp);
 798         error = read_metadata(cp, &md);
 799         g_detach(cp);
 800         g_destroy_consumer(cp);
 801         g_destroy_geom(gp);
 802
 803         if (error != 0)
 804                 return (NULL);
 805
 806         if (strcmp(md.md_magic, G_VIRSTOR_MAGIC) != 0)
 807                 return (NULL);
 808         if (md.md_version != G_VIRSTOR_VERSION) {
 809                 LOG_MSG(LVL_ERROR, "Kernel module version invalid "
 810                     "to handle %s (%s) : %d should be %d",
 811                     md.md_name, pp->name, md.md_version, G_VIRSTOR_VERSION);
 812                 return (NULL);
 813         }
 814         if (md.provsize != pp->mediasize)
 815                 return (NULL);
 816
 817         /* If the provider name is hardcoded, use the offered provider only
 818          * if it's been offered with its proper name (the one used in
 819          * the label command). */
 820         if (md.provider[0] != '\0' &&
 821             !g_compare_names(md.provider, pp->name))
 822                 return (NULL);
 823
 824         /* Iterate all geoms this class already knows about to see if a new
 825          * geom instance of this class needs to be created (in case the provider
 826          * is first from a (possibly) multi-consumer geom) or it just needs
 827          * to be added to an existing instance. */
 828         sc = NULL;
 829         gp = NULL;
 830         LIST_FOREACH(gp, &mp->geom, geom) {
 831                 sc = gp->softc;
 832                 if (sc == NULL)
 833                         continue;
 834                 if (strcmp(md.md_name, sc->geom->name) != 0)
 835                         continue;
 836                 if (md.md_id != sc->id)
 837                         continue;
 838                 break;
 839         }
 840         if (gp != NULL) { /* We found an existing geom instance; add to it */
 841                 LOG_MSG(LVL_INFO, "Adding %s to %s", pp->name, md.md_name);
 842                 error = add_provider_to_geom(sc, pp, &md);
 843                 if (error != 0) {
 844                         LOG_MSG(LVL_ERROR, "Error adding %s to %s (error %d)",
 845                             pp->name, md.md_name, error);
 846                         return (NULL);
 847                 }
 848         } else { /* New geom instance needs to be created */
 849                 gp = create_virstor_geom(mp, &md);
 850                 if (gp == NULL) {
 851                         LOG_MSG(LVL_ERROR, "Error creating new instance of "
 852                             "class %s: %s", mp->name, md.md_name);
 853                         LOG_MSG(LVL_DEBUG, "Error creating %s at %s",
 854                             md.md_name, pp->name);
 855                         return (NULL);
 856                 }
 857                 sc = gp->softc;
 858                 LOG_MSG(LVL_INFO, "Adding %s to %s (first found)", pp->name,
 859                     md.md_name);
 860                 error = add_provider_to_geom(sc, pp, &md);
 861                 if (error != 0) {
 862                         LOG_MSG(LVL_ERROR, "Error adding %s to %s (error %d)",
 863                             pp->name, md.md_name, error);
 864                         virstor_geom_destroy(sc, TRUE, FALSE);
 865                         return (NULL);
 866                 }
 867         }
 868
 869         return (gp);
 870 }
 871
 872 /*
 873  * Destroyes consumer passed to it in arguments. Used as a callback
 874  * on g_event queue.
 875  */
 876 static void
 877 delay_destroy_consumer(void *arg, int flags __unused)
 878 {
 879         struct g_consumer *c = arg;
 880         KASSERT(c != NULL, ("%s: invalid consumer", __func__));
 881         LOG_MSG(LVL_DEBUG, "Consumer %s destroyed with delay",
 882             c->provider->name);
 883         g_detach(c);
 884         g_destroy_consumer(c);
 885 }
 886
 887 /*
 888  * Remove a component (consumer) from geom instance; If it's the first
 889  * component being removed, orphan the provider to announce geom's being
 890  * dismantled
 891  */
 892 static void
 893 remove_component(struct g_virstor_softc *sc, struct g_virstor_component *comp,
 894     boolean_t delay)
 895 {
 896         struct g_consumer *c;
 897
 898         KASSERT(comp->gcons != NULL, ("Component with no consumer in %s",
 899             sc->geom->name));
 900         c = comp->gcons;
 901
 902         comp->gcons = NULL;
 903         KASSERT(c->provider != NULL, ("%s: no provider", __func__));
 904         LOG_MSG(LVL_DEBUG, "Component %s removed from %s", c->provider->name,
 905             sc->geom->name);
 906         if (sc->provider != NULL) {
 907                 LOG_MSG(LVL_INFO, "Removing provider %s", sc->provider->name);
 908                 g_wither_provider(sc->provider, ENXIO);
 909                 sc->provider = NULL;
 910         }
 911
 912         if (c->acr > 0 || c->acw > 0 || c->ace > 0)
 913                 g_access(c, -c->acr, -c->acw, -c->ace);
 914         if (delay) {
 915                 /* Destroy consumer after it's tasted */
 916                 g_post_event(delay_destroy_consumer, c, M_WAITOK, NULL);
 917         } else {
 918                 g_detach(c);
 919                 g_destroy_consumer(c);
 920         }
 921 }
 922
 923 /*
 924  * Destroy geom - called internally
 925  * See g_virstor_destroy_geom for the other one
 926  */
 927 static int
 928 virstor_geom_destroy(struct g_virstor_softc *sc, boolean_t force,
 929     boolean_t delay)
 930 {
 931         struct g_provider *pp;
 932         struct g_geom *gp;
 933         u_int n;
 934
 935         g_topology_assert();
 936
 937         if (sc == NULL)
 938                 return (ENXIO);
 939
 940         pp = sc->provider;
 941         if (pp != NULL && (pp->acr != 0 || pp->acw != 0 || pp->ace != 0)) {
 942                 LOG_MSG(force ? LVL_WARNING : LVL_ERROR,
 943                     "Device %s is still open.", pp->name);
 944                 if (!force)
 945                         return (EBUSY);
 946         }
 947
 948         for (n = 0; n < sc->n_components; n++) {
 949                 if (sc->components[n].gcons != NULL)
 950                         remove_component(sc, &sc->components[n], delay);
 951         }
 952
 953         gp = sc->geom;
 954         gp->softc = NULL;
 955
 956         KASSERT(sc->provider == NULL, ("Provider still exists for %s",
 957             gp->name));
 958
 959         /* XXX: This might or might not work, since we're called with
 960          * the topology lock held. Also, it might panic the kernel if
 961          * the error'd BIO is in softupdates code. */
 962         mtx_lock(&sc->delayed_bio_q_mtx);
 963         while (!STAILQ_EMPTY(&sc->delayed_bio_q)) {
 964                 struct g_virstor_bio_q *bq;
 965                 bq = STAILQ_FIRST(&sc->delayed_bio_q);
 966                 bq->bio->bio_error = ENOSPC;
 967                 g_io_deliver(bq->bio, EIO);
 968                 STAILQ_REMOVE_HEAD(&sc->delayed_bio_q, linkage);
 969                 free(bq, M_GVIRSTOR);
 970         }
 971         mtx_unlock(&sc->delayed_bio_q_mtx);
 972         mtx_destroy(&sc->delayed_bio_q_mtx);
 973
 974         free(sc->map, M_GVIRSTOR);
 975         free(sc->components, M_GVIRSTOR);
 976         bzero(sc, sizeof *sc);
 977         free(sc, M_GVIRSTOR);
 978
 979         pp = LIST_FIRST(&gp->provider); /* We only offer one provider */
 980         if (pp == NULL || (pp->acr == 0 && pp->acw == 0 && pp->ace == 0))
 981                 LOG_MSG(LVL_DEBUG, "Device %s destroyed", gp->name);
 982
 983         g_wither_geom(gp, ENXIO);
 984
 985         return (0);
 986 }
 987
 988 /*
 989  * Utility function: read metadata & decode. Wants topology lock to be
 990  * held.
 991  */
 992 static int
 993 read_metadata(struct g_consumer *cp, struct g_virstor_metadata *md)
 994 {
 995         struct g_provider *pp;
 996         char *buf;
 997         int error;
 998
 999         g_topology_assert();
1000         error = g_access(cp, 1, 0, 0);
1001         if (error != 0)
1002                 return (error);
1003         pp = cp->provider;
1004         g_topology_unlock();
1005         buf = g_read_data(cp, pp->mediasize - pp->sectorsize, pp->sectorsize,
1006             &error);
1007         g_topology_lock();
1008         g_access(cp, -1, 0, 0);
1009         if (buf == NULL)
1010                 return (error);
1011
1012         virstor_metadata_decode(buf, md);
1013         g_free(buf);
1014
1015         return (0);
1016 }
1017
1018 /**
1019  * Utility function: encode & write metadata. Assumes topology lock is
1020  * held.
1021  *
1022  * There is no useful way of recovering from errors in this function,
1023  * not involving panicking the kernel. If the metadata cannot be written
1024  * the most we can do is notify the operator and hope he spots it and
1025  * replaces the broken drive.
1026  */
1027 static void
1028 write_metadata(struct g_consumer *cp, struct g_virstor_metadata *md)
1029 {
1030         struct g_provider *pp;
1031         char *buf;
1032         int error;
1033
1034         KASSERT(cp != NULL && md != NULL && cp->provider != NULL,
1035             ("Something's fishy in %s", __func__));
1036         LOG_MSG(LVL_DEBUG, "Writing metadata on %s", cp->provider->name);
1037         g_topology_assert();
1038         error = g_access(cp, 0, 1, 0);
1039         if (error != 0) {
1040                 LOG_MSG(LVL_ERROR, "g_access(0,1,0) failed for %s: %d",
1041                     cp->provider->name, error);
1042                 return;
1043         }
1044         pp = cp->provider;
1045
1046         buf = malloc(pp->sectorsize, M_GVIRSTOR, M_WAITOK);
1047         virstor_metadata_encode(md, buf);
1048         g_topology_unlock();
1049         error = g_write_data(cp, pp->mediasize - pp->sectorsize, buf,
1050             pp->sectorsize);
1051         g_topology_lock();
1052         g_access(cp, 0, -1, 0);
1053         free(buf, M_GVIRSTOR);
1054
1055         if (error != 0)
1056                 LOG_MSG(LVL_ERROR, "Error %d writing metadata to %s",
1057                     error, cp->provider->name);
1058 }
1059
1060 /*
1061  * Creates a new instance of this GEOM class, initialise softc
1062  */
1063 static struct g_geom *
1064 create_virstor_geom(struct g_class *mp, struct g_virstor_metadata *md)
1065 {
1066         struct g_geom *gp;
1067         struct g_virstor_softc *sc;
1068
1069         LOG_MSG(LVL_DEBUG, "Creating geom instance for %s (id=%u)",
1070             md->md_name, md->md_id);
1071
1072         if (md->md_count < 1 || md->md_chunk_size < 1 ||
1073             md->md_virsize < md->md_chunk_size) {
1074                 /* This is bogus configuration, and probably means data is
1075                  * somehow corrupted. Panic, maybe? */
1076                 LOG_MSG(LVL_ERROR, "Nonsensical metadata information for %s",
1077                     md->md_name);
1078                 return (NULL);
1079         }
1080
1081         /* Check if it's already created */
1082         LIST_FOREACH(gp, &mp->geom, geom) {
1083                 sc = gp->softc;
1084                 if (sc != NULL && strcmp(sc->geom->name, md->md_name) == 0) {
1085                         LOG_MSG(LVL_WARNING, "Geom %s already exists",
1086                             md->md_name);
1087                         if (sc->id != md->md_id) {
1088                                 LOG_MSG(LVL_ERROR,
1089                                     "Some stale or invalid components "
1090                                     "exist for virstor device named %s. "
1091                                     "You will need to <CLEAR> all stale "
1092                                     "components and maybe reconfigure "
1093                                     "the virstor device. Tune "
1094                                     "kern.geom.virstor.debug sysctl up "
1095                                     "for more information.",
1096                                     sc->geom->name);
1097                         }
1098                         return (NULL);
1099                 }
1100         }
1101         gp = g_new_geomf(mp, "%s", md->md_name);
1102         gp->softc = NULL; /* to circumevent races that test softc */
1103
1104         gp->start = g_virstor_start;
1105         gp->spoiled = g_virstor_orphan;
1106         gp->orphan = g_virstor_orphan;
1107         gp->access = g_virstor_access;
1108         gp->dumpconf = g_virstor_dumpconf;
1109
1110         sc = malloc(sizeof(*sc), M_GVIRSTOR, M_WAITOK | M_ZERO);
1111         sc->id = md->md_id;
1112         sc->n_components = md->md_count;
1113         sc->components = malloc(sizeof(struct g_virstor_component) * md->md_count,
1114             M_GVIRSTOR, M_WAITOK | M_ZERO);
1115         sc->chunk_size = md->md_chunk_size;
1116         sc->virsize = md->md_virsize;
1117         STAILQ_INIT(&sc->delayed_bio_q);
1118         mtx_init(&sc->delayed_bio_q_mtx, "gvirstor_delayed_bio_q_mtx",
1119             "gvirstor", MTX_DEF | MTX_RECURSE);
1120
1121         sc->geom = gp;
1122         sc->provider = NULL; /* virstor_check_and_run will create it */
1123         gp->softc = sc;
1124
1125         LOG_MSG(LVL_ANNOUNCE, "Device %s created", sc->geom->name);
1126
1127         return (gp);
1128 }
1129
1130 /*
1131  * Add provider to a GEOM class instance
1132  */
1133 static int
1134 add_provider_to_geom(struct g_virstor_softc *sc, struct g_provider *pp,
1135     struct g_virstor_metadata *md)
1136 {
1137         struct g_virstor_component *component;
1138         struct g_consumer *cp, *fcp;
1139         struct g_geom *gp;
1140         int error;
1141
1142         if (md->no >= sc->n_components)
1143                 return (EINVAL);
1144
1145         /* "Current" compontent */
1146         component = &(sc->components[md->no]);
1147         if (component->gcons != NULL)
1148                 return (EEXIST);
1149
1150         gp = sc->geom;
1151         fcp = LIST_FIRST(&gp->consumer);
1152
1153         cp = g_new_consumer(gp);
1154         error = g_attach(cp, pp);
1155
1156         if (error != 0) {
1157                 g_destroy_consumer(cp);
1158                 return (error);
1159         }
1160
1161         if (fcp != NULL) {
1162                 if (fcp->provider->sectorsize != pp->sectorsize) {
1163                         /* TODO: this can be made to work */
1164                         LOG_MSG(LVL_ERROR, "Provider %s of %s has invalid "
1165                             "sector size (%d)", pp->name, sc->geom->name,
1166                             pp->sectorsize);
1167                         return (EINVAL);
1168                 }
1169                 if (fcp->acr > 0 || fcp->acw || fcp->ace > 0) {
1170                         /* Replicate access permissions from first "live" consumer
1171                          * to the new one */
1172                         error = g_access(cp, fcp->acr, fcp->acw, fcp->ace);
1173                         if (error != 0) {
1174                                 g_detach(cp);
1175                                 g_destroy_consumer(cp);
1176                                 return (error);
1177                         }
1178                 }
1179         }
1180
1181         /* Bring up a new component */
1182         cp->private = component;
1183         component->gcons = cp;
1184         component->sc = sc;
1185         component->index = md->no;
1186         component->chunk_count = md->chunk_count;
1187         component->chunk_next = md->chunk_next;
1188         component->chunk_reserved = md->chunk_reserved;
1189         component->flags = md->flags;
1190
1191         LOG_MSG(LVL_DEBUG, "%s attached to %s", pp->name, sc->geom->name);
1192
1193         virstor_check_and_run(sc);
1194         return (0);
1195 }
1196
1197 /*
1198  * Check if everything's ready to create the geom provider & device entry,
1199  * create and start provider.
1200  * Called ultimately by .taste, from g_event thread
1201  */
1202 static void
1203 virstor_check_and_run(struct g_virstor_softc *sc)
1204 {
1205         off_t off;
1206         size_t n, count;
1207         int index;
1208         int error;
1209
1210         if (virstor_valid_components(sc) != sc->n_components)
1211                 return;
1212
1213         if (virstor_valid_components(sc) == 0) {
1214                 /* This is actually a candidate for panic() */
1215                 LOG_MSG(LVL_ERROR, "No valid components for %s?",
1216                     sc->provider->name);
1217                 return;
1218         }
1219
1220         sc->sectorsize = sc->components[0].gcons->provider->sectorsize;
1221
1222         /* Initialise allocation map from the first consumer */
1223         sc->chunk_count = sc->virsize / sc->chunk_size;
1224         if (sc->chunk_count * (off_t)sc->chunk_size != sc->virsize) {
1225                 LOG_MSG(LVL_WARNING, "Device %s truncated to %ju bytes",
1226                     sc->provider->name,
1227                     sc->chunk_count * (off_t)sc->chunk_size);
1228         }
1229         sc->map_size = sc->chunk_count * sizeof *(sc->map);
1230         /* The following allocation is in order of 4MB - 8MB */
1231         sc->map = malloc(sc->map_size, M_GVIRSTOR, M_WAITOK);
1232         KASSERT(sc->map != NULL, ("%s: Memory allocation error (%zu bytes) for %s",
1233             __func__, sc->map_size, sc->provider->name));
1234         sc->map_sectors = sc->map_size / sc->sectorsize;
1235
1236         count = 0;
1237         for (n = 0; n < sc->n_components; n++)
1238                 count += sc->components[n].chunk_count;
1239         LOG_MSG(LVL_INFO, "Device %s has %zu physical chunks and %zu virtual "
1240             "(%zu KB chunks)",
1241             sc->geom->name, count, sc->chunk_count, sc->chunk_size / 1024);
1242
1243         error = g_access(sc->components[0].gcons, 1, 0, 0);
1244         if (error != 0) {
1245                 LOG_MSG(LVL_ERROR, "Cannot acquire read access for %s to "
1246                     "read allocation map for %s",
1247                     sc->components[0].gcons->provider->name,
1248                     sc->geom->name);
1249                 return;
1250         }
1251         /* Read in the allocation map */
1252         LOG_MSG(LVL_DEBUG, "Reading map for %s from %s", sc->geom->name,
1253             sc->components[0].gcons->provider->name);
1254         off = count = n = 0;
1255         while (count < sc->map_size) {
1256                 struct g_virstor_map_entry *mapbuf;
1257                 size_t bs;
1258
1259                 bs = MIN(MAXPHYS, sc->map_size - count);
1260                 if (bs % sc->sectorsize != 0) {
1261                         /* Check for alignment errors */
1262                         bs = (bs / sc->sectorsize) * sc->sectorsize;
1263                         if (bs == 0)
1264                                 break;
1265                         LOG_MSG(LVL_ERROR, "Trouble: map is not sector-aligned "
1266                             "for %s on %s", sc->geom->name,
1267                             sc->components[0].gcons->provider->name);
1268                 }
1269                 mapbuf = g_read_data(sc->components[0].gcons, off, bs, &error);
1270                 if (mapbuf == NULL) {
1271                         free(sc->map, M_GVIRSTOR);
1272                         LOG_MSG(LVL_ERROR, "Error reading allocation map "
1273                             "for %s from %s (offset %ju) (error %d)",
1274                             sc->geom->name,
1275                             sc->components[0].gcons->provider->name,
1276                             off, error);
1277                         return;
1278                 }
1279
1280                 bcopy(mapbuf, &sc->map[n], bs);
1281                 off += bs;
1282                 count += bs;
1283                 n += bs / sizeof *(sc->map);
1284                 g_free(mapbuf);
1285         }
1286         g_access(sc->components[0].gcons, -1, 0, 0);
1287         LOG_MSG(LVL_DEBUG, "Read map for %s", sc->geom->name);
1288
1289         /* find first component with allocatable chunks */
1290         index = -1;
1291         for (n = 0; n < sc->n_components; n++) {
1292                 if (sc->components[n].chunk_next <
1293                     sc->components[n].chunk_count) {
1294                         index = n;
1295                         break;
1296                 }
1297         }
1298         if (index == -1)
1299                 /* not found? set it to the last component and handle it
1300                  * later */
1301                 index = sc->n_components - 1;
1302
1303         if (index >= sc->n_components - g_virstor_component_watermark - 1) {
1304                 LOG_MSG(LVL_WARNING, "Device %s running out of components "
1305                     "(%d/%u: %s)", sc->geom->name,
1306                     index+1,
1307                     sc->n_components,
1308                     sc->components[index].gcons->provider->name);
1309         }
1310         sc->curr_component = index;
1311
1312         if (sc->components[index].chunk_next >=
1313             sc->components[index].chunk_count - g_virstor_chunk_watermark) {
1314                 LOG_MSG(LVL_WARNING,
1315                     "Component %s of %s is running out of free space "
1316                     "(%u chunks left)",
1317                     sc->components[index].gcons->provider->name,
1318                     sc->geom->name, sc->components[index].chunk_count -
1319                     sc->components[index].chunk_next);
1320         }
1321
1322         sc->me_per_sector = sc->sectorsize / sizeof *(sc->map);
1323         if (sc->sectorsize % sizeof *(sc->map) != 0) {
1324                 LOG_MSG(LVL_ERROR,
1325                     "%s: Map entries don't fit exactly in a sector (%s)",
1326                     __func__, sc->geom->name);
1327                 return;
1328         }
1329
1330         /* Recalculate allocated chunks in components & at the same time
1331          * verify map data is sane. We could trust metadata on this, but
1332          * we want to make sure. */
1333         for (n = 0; n < sc->n_components; n++)
1334                 sc->components[n].chunk_next = sc->components[n].chunk_reserved;
1335
1336         for (n = 0; n < sc->chunk_count; n++) {
1337                 if (sc->map[n].provider_no >= sc->n_components ||
1338                         sc->map[n].provider_chunk >=
1339                         sc->components[sc->map[n].provider_no].chunk_count) {
1340                         LOG_MSG(LVL_ERROR, "%s: Invalid entry %u in map for %s",
1341                             __func__, (u_int)n, sc->geom->name);
1342                         LOG_MSG(LVL_ERROR, "%s: provider_no: %u, n_components: %u"
1343                             " provider_chunk: %u, chunk_count: %u", __func__,
1344                             sc->map[n].provider_no, sc->n_components,
1345                             sc->map[n].provider_chunk,
1346                             sc->components[sc->map[n].provider_no].chunk_count);
1347                         return;
1348                 }
1349                 if (sc->map[n].flags & VIRSTOR_MAP_ALLOCATED)
1350                         sc->components[sc->map[n].provider_no].chunk_next++;
1351         }
1352
1353         sc->provider = g_new_providerf(sc->geom, "virstor/%s",
1354             sc->geom->name);
1355
1356         sc->provider->sectorsize = sc->sectorsize;
1357         sc->provider->mediasize = sc->virsize;
1358         g_error_provider(sc->provider, 0);
1359
1360         LOG_MSG(LVL_INFO, "%s activated", sc->provider->name);
1361         LOG_MSG(LVL_DEBUG, "%s starting with current component %u, starting "
1362             "chunk %u", sc->provider->name, sc->curr_component,
1363             sc->components[sc->curr_component].chunk_next);
1364 }
1365
1366 /*
1367  * Returns count of active providers in this geom instance
1368  */
1369 static u_int
1370 virstor_valid_components(struct g_virstor_softc *sc)
1371 {
1372         unsigned int nc, i;
1373
1374         nc = 0;
1375         KASSERT(sc != NULL, ("%s: softc is NULL", __func__));
1376         KASSERT(sc->components != NULL, ("%s: sc->components is NULL", __func__));
1377         for (i = 0; i < sc->n_components; i++)
1378                 if (sc->components[i].gcons != NULL)
1379                         nc++;
1380         return (nc);
1381 }
1382
1383 /*
1384  * Called when the consumer gets orphaned (?)
1385  */
1386 static void
1387 g_virstor_orphan(struct g_consumer *cp)
1388 {
1389         struct g_virstor_softc *sc;
1390         struct g_virstor_component *comp;
1391         struct g_geom *gp;
1392
1393         g_topology_assert();
1394         gp = cp->geom;
1395         sc = gp->softc;
1396         if (sc == NULL)
1397                 return;
1398
1399         comp = cp->private;
1400         KASSERT(comp != NULL, ("%s: No component in private part of consumer",
1401             __func__));
1402         remove_component(sc, comp, FALSE);
1403         if (virstor_valid_components(sc) == 0)
1404                 virstor_geom_destroy(sc, TRUE, FALSE);
1405 }
1406
1407 /*
1408  * Called to notify geom when it's been opened, and for what intent
1409  */
1410 static int
1411 g_virstor_access(struct g_provider *pp, int dr, int dw, int de)
1412 {
1413         struct g_consumer *c;
1414         struct g_virstor_softc *sc;
1415         struct g_geom *gp;
1416         int error;
1417
1418         KASSERT(pp != NULL, ("%s: NULL provider", __func__));
1419         gp = pp->geom;
1420         KASSERT(gp != NULL, ("%s: NULL geom", __func__));
1421         sc = gp->softc;
1422
1423         if (sc == NULL) {
1424                 /* It seems that .access can be called with negative dr,dw,dx
1425                  * in this case but I want to check for myself */
1426                 LOG_MSG(LVL_WARNING, "access(%d, %d, %d) for %s",
1427                     dr, dw, de, pp->name);
1428                 /* This should only happen when geom is withered so
1429                  * allow only negative requests */
1430                 KASSERT(dr <= 0 && dw <= 0 && de <= 0,
1431                     ("%s: Positive access for %s", __func__, pp->name));
1432                 if (pp->acr + dr == 0 && pp->acw + dw == 0 && pp->ace + de == 0)
1433                         LOG_MSG(LVL_DEBUG, "Device %s definitely destroyed",
1434                             pp->name);
1435                 return (0);
1436         }
1437
1438         /* Grab an exclusive bit to propagate on our consumers on first open */
1439         if (pp->acr == 0 && pp->acw == 0 && pp->ace == 0)
1440                 de++;
1441         /* ... drop it on close */
1442         if (pp->acr + dr == 0 && pp->acw + dw == 0 && pp->ace + de == 0) {
1443                 de--;
1444                 update_metadata(sc);    /* Writes statistical information */
1445         }
1446
1447         error = ENXIO;
1448         LIST_FOREACH(c, &gp->consumer, consumer) {
1449                 KASSERT(c != NULL, ("%s: consumer is NULL", __func__));
1450                 error = g_access(c, dr, dw, de);
1451                 if (error != 0) {
1452                         struct g_consumer *c2;
1453
1454                         /* Backout earlier changes */
1455                         LIST_FOREACH(c2, &gp->consumer, consumer) {
1456                                 if (c2 == c) /* all eariler components fixed */
1457                                         return (error);
1458                                 g_access(c2, -dr, -dw, -de);
1459                         }
1460                 }
1461         }
1462
1463         return (error);
1464 }
1465
1466 /*
1467  * Generate XML dump of current state
1468  */
1469 static void
1470 g_virstor_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp,
1471     struct g_consumer *cp, struct g_provider *pp)
1472 {
1473         struct g_virstor_softc *sc;
1474
1475         g_topology_assert();
1476         sc = gp->softc;
1477
1478         if (sc == NULL || pp != NULL)
1479                 return;
1480
1481         if (cp != NULL) {
1482                 /* For each component */
1483                 struct g_virstor_component *comp;
1484
1485                 comp = cp->private;
1486                 if (comp == NULL)
1487                         return;
1488                 sbuf_printf(sb, "%s<ComponentIndex>%u</ComponentIndex>\n",
1489                     indent, comp->index);
1490                 sbuf_printf(sb, "%s<ChunkCount>%u</ChunkCount>\n",
1491                     indent, comp->chunk_count);
1492                 sbuf_printf(sb, "%s<ChunksUsed>%u</ChunksUsed>\n",
1493                     indent, comp->chunk_next);
1494                 sbuf_printf(sb, "%s<ChunksReserved>%u</ChunksReserved>\n",
1495                     indent, comp->chunk_reserved);
1496                 sbuf_printf(sb, "%s<StorageFree>%u%%</StorageFree>\n",
1497                     indent,
1498                     comp->chunk_next > 0 ? 100 -
1499                     ((comp->chunk_next + comp->chunk_reserved) * 100) /
1500                     comp->chunk_count : 100);
1501         } else {
1502                 /* For the whole thing */
1503                 u_int count, used, i;
1504                 off_t size;
1505
1506                 count = used = size = 0;
1507                 for (i = 0; i < sc->n_components; i++) {
1508                         if (sc->components[i].gcons != NULL) {
1509                                 count += sc->components[i].chunk_count;
1510                                 used += sc->components[i].chunk_next +
1511                                     sc->components[i].chunk_reserved;
1512                                 size += sc->components[i].gcons->
1513                                     provider->mediasize;
1514                         }
1515                 }
1516
1517                 sbuf_printf(sb, "%s<Status>"
1518                     "Components=%u, Online=%u</Status>\n", indent,
1519                     sc->n_components, virstor_valid_components(sc));
1520                 sbuf_printf(sb, "%s<State>%u%% physical free</State>\n",
1521                     indent, 100-(used * 100) / count);
1522                 sbuf_printf(sb, "%s<ChunkSize>%zu</ChunkSize>\n", indent,
1523                     sc->chunk_size);
1524                 sbuf_printf(sb, "%s<PhysicalFree>%u%%</PhysicalFree>\n",
1525                     indent, used > 0 ? 100 - (used * 100) / count : 100);
1526                 sbuf_printf(sb, "%s<ChunkPhysicalCount>%u</ChunkPhysicalCount>\n",
1527                     indent, count);
1528                 sbuf_printf(sb, "%s<ChunkVirtualCount>%zu</ChunkVirtualCount>\n",
1529                     indent, sc->chunk_count);
1530                 sbuf_printf(sb, "%s<PhysicalBacking>%zu%%</PhysicalBacking>\n",
1531                     indent,
1532                     (count * 100) / sc->chunk_count);
1533                 sbuf_printf(sb, "%s<PhysicalBackingSize>%jd</PhysicalBackingSize>\n",
1534                     indent, size);
1535                 sbuf_printf(sb, "%s<VirtualSize>%jd</VirtualSize>\n", indent,
1536                     sc->virsize);
1537         }
1538 }
1539
1540 /*
1541  * GEOM .done handler
1542  * Can't use standard handler because one requested IO may
1543  * fork into additional data IOs
1544  */
1545 static void
1546 g_virstor_done(struct bio *b)
1547 {
1548         struct g_virstor_softc *sc;
1549         struct bio *parent_b;
1550
1551         parent_b = b->bio_parent;
1552         sc = parent_b->bio_to->geom->softc;
1553
1554         if (b->bio_error != 0) {
1555                 LOG_MSG(LVL_ERROR, "Error %d for offset=%ju, length=%ju, %s",
1556                     b->bio_error, b->bio_offset, b->bio_length,
1557                     b->bio_to->name);
1558                 if (parent_b->bio_error == 0)
1559                         parent_b->bio_error = b->bio_error;
1560         }
1561
1562         parent_b->bio_inbed++;
1563         parent_b->bio_completed += b->bio_completed;
1564
1565         if (parent_b->bio_children == parent_b->bio_inbed) {
1566                 parent_b->bio_completed = parent_b->bio_length;
1567                 g_io_deliver(parent_b, parent_b->bio_error);
1568         }
1569         g_destroy_bio(b);
1570 }
1571
1572 /*
1573  * I/O starts here
1574  * Called in g_down thread
1575  */
1576 static void
1577 g_virstor_start(struct bio *b)
1578 {
1579         struct g_virstor_softc *sc;
1580         struct g_virstor_component *comp;
1581         struct bio *cb;
1582         struct g_provider *pp;
1583         char *addr;
1584         off_t offset, length;
1585         struct bio_queue_head bq;
1586         size_t chunk_size;      /* cached for convenience */
1587         u_int count;
1588
1589         pp = b->bio_to;
1590         sc = pp->geom->softc;
1591         KASSERT(sc != NULL, ("%s: no softc (error=%d, device=%s)", __func__,
1592             b->bio_to->error, b->bio_to->name));
1593
1594         LOG_REQ(LVL_MOREDEBUG, b, "%s", __func__);
1595
1596         switch (b->bio_cmd) {
1597         case BIO_READ:
1598         case BIO_WRITE:
1599         case BIO_DELETE:
1600                 break;
1601         default:
1602                 g_io_deliver(b, EOPNOTSUPP);
1603                 return;
1604         }
1605
1606         LOG_MSG(LVL_DEBUG2, "BIO arrived, size=%ju", b->bio_length);
1607         bioq_init(&bq);
1608
1609         chunk_size = sc->chunk_size;
1610         addr = b->bio_data;
1611         offset = b->bio_offset; /* virtual offset and length */
1612         length = b->bio_length;
1613
1614         while (length > 0) {
1615                 size_t chunk_index, in_chunk_offset, in_chunk_length;
1616                 struct virstor_map_entry *me;
1617
1618                 chunk_index = offset / chunk_size; /* round downwards */
1619                 in_chunk_offset = offset % chunk_size;
1620                 in_chunk_length = min(length, chunk_size - in_chunk_offset);
1621                 LOG_MSG(LVL_DEBUG, "Mapped %s(%ju, %ju) to (%zu,%zu,%zu)",
1622                     b->bio_cmd == BIO_READ ? "R" : "W",
1623                     offset, length,
1624                     chunk_index, in_chunk_offset, in_chunk_length);
1625                 me = &sc->map[chunk_index];
1626
1627                 if (b->bio_cmd == BIO_READ || b->bio_cmd == BIO_DELETE) {
1628                         if ((me->flags & VIRSTOR_MAP_ALLOCATED) == 0) {
1629                                 /* Reads from unallocated chunks return zeroed
1630                                  * buffers */
1631                                 if (b->bio_cmd == BIO_READ)
1632                                         bzero(addr, in_chunk_length);
1633                         } else {
1634                                 comp = &sc->components[me->provider_no];
1635
1636                                 cb = g_clone_bio(b);
1637                                 if (cb == NULL) {
1638                                         bioq_dismantle(&bq);
1639                                         if (b->bio_error == 0)
1640                                                 b->bio_error = ENOMEM;
1641                                         g_io_deliver(b, b->bio_error);
1642                                         return;
1643                                 }
1644                                 cb->bio_to = comp->gcons->provider;
1645                                 cb->bio_done = g_virstor_done;
1646                                 cb->bio_offset =
1647                                     (off_t)me->provider_chunk * (off_t)chunk_size
1648                                     + in_chunk_offset;
1649                                 cb->bio_length = in_chunk_length;
1650                                 cb->bio_data = addr;
1651                                 cb->bio_caller1 = comp;
1652                                 bioq_disksort(&bq, cb);
1653                         }
1654                 } else { /* handle BIO_WRITE */
1655                         KASSERT(b->bio_cmd == BIO_WRITE,
1656                             ("%s: Unknown command %d", __func__,
1657                             b->bio_cmd));
1658
1659                         if ((me->flags & VIRSTOR_MAP_ALLOCATED) == 0) {
1660                                 /* We have a virtual chunk, represented by
1661                                  * the "me" entry, but it's not yet allocated
1662                                  * (tied to) a physical chunk. So do it now. */
1663                                 struct virstor_map_entry *data_me;
1664                                 u_int phys_chunk, comp_no;
1665                                 off_t s_offset;
1666                                 int error;
1667
1668                                 error = allocate_chunk(sc, &comp, &comp_no,
1669                                     &phys_chunk);
1670                                 if (error != 0) {
1671                                         /* We cannot allocate a physical chunk
1672                                          * to satisfy this request, so we'll
1673                                          * delay it to when we can...
1674                                          * XXX: this will prevent the fs from
1675                                          * being umounted! */
1676                                         struct g_virstor_bio_q *biq;
1677                                         biq = malloc(sizeof *biq, M_GVIRSTOR,
1678                                             M_NOWAIT);
1679                                         if (biq == NULL) {
1680                                                 bioq_dismantle(&bq);
1681                                                 if (b->bio_error == 0)
1682                                                         b->bio_error = ENOMEM;
1683                                                 g_io_deliver(b, b->bio_error);
1684                                                 return;
1685                                         }
1686                                         biq->bio = b;
1687                                         mtx_lock(&sc->delayed_bio_q_mtx);
1688                                         STAILQ_INSERT_TAIL(&sc->delayed_bio_q,
1689                                             biq, linkage);
1690                                         mtx_unlock(&sc->delayed_bio_q_mtx);
1691                                         LOG_MSG(LVL_WARNING, "Delaying BIO "
1692                                             "(size=%ju) until free physical "
1693                                             "space can be found on %s",
1694                                             b->bio_length,
1695                                             sc->provider->name);
1696                                         return;
1697                                 }
1698                                 LOG_MSG(LVL_DEBUG, "Allocated chunk %u on %s "
1699                                     "for %s",
1700                                     phys_chunk,
1701                                     comp->gcons->provider->name,
1702                                     sc->provider->name);
1703
1704                                 me->provider_no = comp_no;
1705                                 me->provider_chunk = phys_chunk;
1706                                 me->flags |= VIRSTOR_MAP_ALLOCATED;
1707
1708                                 cb = g_clone_bio(b);
1709                                 if (cb == NULL) {
1710                                         me->flags &= ~VIRSTOR_MAP_ALLOCATED;
1711                                         me->provider_no = 0;
1712                                         me->provider_chunk = 0;
1713                                         bioq_dismantle(&bq);
1714                                         if (b->bio_error == 0)
1715                                                 b->bio_error = ENOMEM;
1716                                         g_io_deliver(b, b->bio_error);
1717                                         return;
1718                                 }
1719
1720                                 /* The allocation table is stored continuously
1721                                  * at the start of the drive. We need to
1722                                  * calculate the offset of the sector that holds
1723                                  * this map entry both on the drive and in the
1724                                  * map array.
1725                                  * sc_offset will end up pointing to the drive
1726                                  * sector. */
1727                                 s_offset = chunk_index * sizeof *me;
1728                                 s_offset = (s_offset / sc->sectorsize) *
1729                                     sc->sectorsize;
1730
1731                                 /* data_me points to map entry sector
1732                                  * in memory (analoguos to offset) */
1733                                 data_me = &sc->map[(chunk_index /
1734                                     sc->me_per_sector) * sc->me_per_sector];
1735
1736                                 /* Commit sector with map entry to storage */
1737                                 cb->bio_to = sc->components[0].gcons->provider;
1738                                 cb->bio_done = g_virstor_done;
1739                                 cb->bio_offset = s_offset;
1740                                 cb->bio_data = (char *)data_me;
1741                                 cb->bio_length = sc->sectorsize;
1742                                 cb->bio_caller1 = &sc->components[0];
1743                                 bioq_disksort(&bq, cb);
1744                         }
1745
1746                         comp = &sc->components[me->provider_no];
1747                         cb = g_clone_bio(b);
1748                         if (cb == NULL) {
1749                                 bioq_dismantle(&bq);
1750                                 if (b->bio_error == 0)
1751                                         b->bio_error = ENOMEM;
1752                                 g_io_deliver(b, b->bio_error);
1753                                 return;
1754                         }
1755                         /* Finally, handle the data */
1756                         cb->bio_to = comp->gcons->provider;
1757                         cb->bio_done = g_virstor_done;
1758                         cb->bio_offset = (off_t)me->provider_chunk*(off_t)chunk_size +
1759                             in_chunk_offset;
1760                         cb->bio_length = in_chunk_length;
1761                         cb->bio_data = addr;
1762                         cb->bio_caller1 = comp;
1763                         bioq_disksort(&bq, cb);
1764                 }
1765                 addr += in_chunk_length;
1766                 length -= in_chunk_length;
1767                 offset += in_chunk_length;
1768         }
1769
1770         /* Fire off bio's here */
1771         count = 0;
1772         for (cb = bioq_first(&bq); cb != NULL; cb = bioq_first(&bq)) {
1773                 bioq_remove(&bq, cb);
1774                 LOG_REQ(LVL_MOREDEBUG, cb, "Firing request");
1775                 comp = cb->bio_caller1;
1776                 cb->bio_caller1 = NULL;
1777                 LOG_MSG(LVL_DEBUG, " firing bio, offset=%ju, length=%ju",
1778                     cb->bio_offset, cb->bio_length);
1779                 g_io_request(cb, comp->gcons);
1780                 count++;
1781         }
1782         if (count == 0) { /* We handled everything locally */
1783                 b->bio_completed = b->bio_length;
1784                 g_io_deliver(b, 0);
1785         }
1786
1787 }
1788
1789 /*
1790  * Allocate a chunk from a physical provider. Returns physical component,
1791  * chunk index relative to the component and the component's index.
1792  */
1793 static int
1794 allocate_chunk(struct g_virstor_softc *sc, struct g_virstor_component **comp,
1795     u_int *comp_no_p, u_int *chunk)
1796 {
1797         u_int comp_no;
1798
1799         KASSERT(sc->curr_component < sc->n_components,
1800             ("%s: Invalid curr_component: %u",  __func__, sc->curr_component));
1801
1802         comp_no = sc->curr_component;
1803         *comp = &sc->components[comp_no];
1804         dump_component(*comp);
1805         if ((*comp)->chunk_next >= (*comp)->chunk_count) {
1806                 /* This component is full. Allocate next component */
1807                 if (comp_no >= sc->n_components-1) {
1808                         LOG_MSG(LVL_ERROR, "All physical space allocated for %s",
1809                             sc->geom->name);
1810                         return (-1);
1811                 }
1812                 (*comp)->flags &= ~VIRSTOR_PROVIDER_CURRENT;
1813                 sc->curr_component = ++comp_no;
1814
1815                 *comp = &sc->components[comp_no];
1816                 if (comp_no >= sc->n_components - g_virstor_component_watermark-1)
1817                         LOG_MSG(LVL_WARNING, "Device %s running out of components "
1818                             "(switching to %u/%u: %s)", sc->geom->name,
1819                             comp_no+1, sc->n_components,
1820                             (*comp)->gcons->provider->name);
1821                 /* Take care not to overwrite reserved chunks */
1822                 if ( (*comp)->chunk_reserved > 0 &&
1823                     (*comp)->chunk_next < (*comp)->chunk_reserved)
1824                         (*comp)->chunk_next = (*comp)->chunk_reserved;
1825
1826                 (*comp)->flags |=
1827                     VIRSTOR_PROVIDER_ALLOCATED | VIRSTOR_PROVIDER_CURRENT;
1828                 dump_component(*comp);
1829                 *comp_no_p = comp_no;
1830                 *chunk = (*comp)->chunk_next++;
1831         } else {
1832                 *comp_no_p = comp_no;
1833                 *chunk = (*comp)->chunk_next++;
1834         }
1835         return (0);
1836 }
1837
1838 /* Dump a component */
1839 static void
1840 dump_component(struct g_virstor_component *comp)
1841 {
1842
1843         if (g_virstor_debug < LVL_DEBUG2)
1844                 return;
1845         printf("Component %d: %s\n", comp->index, comp->gcons->provider->name);
1846         printf("  chunk_count: %u\n", comp->chunk_count);
1847         printf("   chunk_next: %u\n", comp->chunk_next);
1848         printf("        flags: %u\n", comp->flags);
1849 }
1850
1851 #if 0
1852 /* Dump a map entry */
1853 static void
1854 dump_me(struct virstor_map_entry *me, unsigned int nr)
1855 {
1856         if (g_virstor_debug < LVL_DEBUG)
1857                 return;
1858         printf("VIRT. CHUNK #%d: ", nr);
1859         if ((me->flags & VIRSTOR_MAP_ALLOCATED) == 0)
1860                 printf("(unallocated)\n");
1861         else
1862                 printf("allocated at provider %u, provider_chunk %u\n",
1863                     me->provider_no, me->provider_chunk);
1864 }
1865 #endif
1866
1867 /*
1868  * Dismantle bio_queue and destroy its components
1869  */
1870 static void
1871 bioq_dismantle(struct bio_queue_head *bq)
1872 {
1873         struct bio *b;
1874
1875         for (b = bioq_first(bq); b != NULL; b = bioq_first(bq)) {
1876                 bioq_remove(bq, b);
1877                 g_destroy_bio(b);
1878         }
1879 }
1880
1881 /*
1882  * The function that shouldn't be called.
1883  * When this is called, the stack is already garbled because of
1884  * argument mismatch. There's nothing to do now but panic, which is
1885  * accidentally the whole purpose of this function.
1886  * Motivation: to guard from accidentally calling geom methods when
1887  * they shouldn't be called. (see g_..._taste)
1888  */
1889 static void
1890 invalid_call(void)
1891 {
1892         panic("invalid_call() has just been called. Something's fishy here.");
1893 }
1894
1895 DECLARE_GEOM_CLASS(g_virstor_class, g_virstor); /* Let there be light */