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 SYSCTL_NODE(_kern_geom, OID_AUTO, virstor, CTLFLAG_RW, 0, "GEOM_GVIRSTOR information");
  84
  85 static u_int g_virstor_debug = 2; /* XXX: lower to 2 when released to public */
  86 TUNABLE_INT("kern.geom.virstor.debug", &g_virstor_debug);
  87 SYSCTL_UINT(_kern_geom_virstor, OID_AUTO, debug, CTLFLAG_RW, &g_virstor_debug,
  88     0, "Debug level (2=production, 5=normal, 15=excessive)");
  89
  90 static u_int g_virstor_chunk_watermark = 100;
  91 TUNABLE_INT("kern.geom.virstor.chunk_watermark", &g_virstor_chunk_watermark);
  92 SYSCTL_UINT(_kern_geom_virstor, OID_AUTO, chunk_watermark, CTLFLAG_RW,
  93     &g_virstor_chunk_watermark, 0,
  94     "Minimum number of free chunks before issuing administrative warning");
  95
  96 static u_int g_virstor_component_watermark = 1;
  97 TUNABLE_INT("kern.geom.virstor.component_watermark",
  98     &g_virstor_component_watermark);
  99 SYSCTL_UINT(_kern_geom_virstor, OID_AUTO, component_watermark, CTLFLAG_RW,
 100     &g_virstor_component_watermark, 0,
 101     "Minimum number of free components before issuing administrative warning");
 102
 103 static int read_metadata(struct g_consumer *, struct g_virstor_metadata *);
 104 static void write_metadata(struct g_consumer *, struct g_virstor_metadata *);
 105 static int clear_metadata(struct g_virstor_component *);
 106 static int add_provider_to_geom(struct g_virstor_softc *, struct g_provider *,
 107     struct g_virstor_metadata *);
 108 static struct g_geom *create_virstor_geom(struct g_class *,
 109     struct g_virstor_metadata *);
 110 static void virstor_check_and_run(struct g_virstor_softc *);
 111 static u_int virstor_valid_components(struct g_virstor_softc *);
 112 static int virstor_geom_destroy(struct g_virstor_softc *, boolean_t,
 113     boolean_t);
 114 static void remove_component(struct g_virstor_softc *,
 115     struct g_virstor_component *, boolean_t);
 116 static void bioq_dismantle(struct bio_queue_head *);
 117 static int allocate_chunk(struct g_virstor_softc *,
 118     struct g_virstor_component **, u_int *, u_int *);
 119 static void delay_destroy_consumer(void *, int);
 120 static void dump_component(struct g_virstor_component *comp);
 121 #if 0
 122 static void dump_me(struct virstor_map_entry *me, unsigned int nr);
 123 #endif
 124
 125 static void virstor_ctl_stop(struct gctl_req *, struct g_class *);
 126 static void virstor_ctl_add(struct gctl_req *, struct g_class *);
 127 static void virstor_ctl_remove(struct gctl_req *, struct g_class *);
 128 static struct g_virstor_softc * virstor_find_geom(const struct g_class *,
 129     const char *);
 130 static void update_metadata(struct g_virstor_softc *);
 131 static void fill_metadata(struct g_virstor_softc *, struct g_virstor_metadata *,
 132     u_int, u_int);
 133
 134 static void g_virstor_orphan(struct g_consumer *);
 135 static int g_virstor_access(struct g_provider *, int, int, int);
 136 static void g_virstor_start(struct bio *);
 137 static void g_virstor_dumpconf(struct sbuf *, const char *, struct g_geom *,
 138     struct g_consumer *, struct g_provider *);
 139 static void g_virstor_done(struct bio *);
 140
 141 static void invalid_call(void);
 142 /*
 143  * Initialise GEOM class (per-class callback)
 144  */
 145 static void
 146 g_virstor_init(struct g_class *mp __unused)
 147 {
 148
 149         /* Catch map struct size mismatch at compile time; Map entries must
 150          * fit into MAXPHYS exactly, with no wasted space. */
 151         CTASSERT(VIRSTOR_MAP_BLOCK_ENTRIES*VIRSTOR_MAP_ENTRY_SIZE == MAXPHYS);
 152
 153         /* Init UMA zones, TAILQ's, other global vars */
 154 }
 155
 156 /*
 157  * Finalise GEOM class (per-class callback)
 158  */
 159 static void
 160 g_virstor_fini(struct g_class *mp __unused)
 161 {
 162
 163         /* Deinit UMA zones & global vars */
 164 }
 165
 166 /*
 167  * Config (per-class callback)
 168  */
 169 static void
 170 g_virstor_config(struct gctl_req *req, struct g_class *cp, char const *verb)
 171 {
 172         uint32_t *version;
 173
 174         g_topology_assert();
 175
 176         version = gctl_get_paraml(req, "version", sizeof(*version));
 177         if (version == NULL) {
 178                 gctl_error(req, "Failed to get 'version' argument");
 179                 return;
 180         }
 181         if (*version != G_VIRSTOR_VERSION) {
 182                 gctl_error(req, "Userland and kernel versions out of sync");
 183                 return;
 184         }
 185
 186         g_topology_unlock();
 187         if (strcmp(verb, "add") == 0)
 188                 virstor_ctl_add(req, cp);
 189         else if (strcmp(verb, "stop") == 0 || strcmp(verb, "destroy") == 0)
 190                 virstor_ctl_stop(req, cp);
 191         else if (strcmp(verb, "remove") == 0)
 192                 virstor_ctl_remove(req, cp);
 193         else
 194                 gctl_error(req, "unknown verb: '%s'", verb);
 195         g_topology_lock();
 196 }
 197
 198 /*
 199  * "stop" verb from userland
 200  */
 201 static void
 202 virstor_ctl_stop(struct gctl_req *req, struct g_class *cp)
 203 {
 204         int *force, *nargs;
 205         int i;
 206
 207         nargs = gctl_get_paraml(req, "nargs", sizeof *nargs);
 208         if (nargs == NULL) {
 209                 gctl_error(req, "Error fetching argument '%s'", "nargs");
 210                 return;
 211         }
 212         if (*nargs < 1) {
 213                 gctl_error(req, "Invalid number of arguments");
 214                 return;
 215         }
 216         force = gctl_get_paraml(req, "force", sizeof *force);
 217         if (force == NULL) {
 218                 gctl_error(req, "Error fetching argument '%s'", "force");
 219                 return;
 220         }
 221
 222         g_topology_lock();
 223         for (i = 0; i < *nargs; i++) {
 224                 char param[8];
 225                 const char *name;
 226                 struct g_virstor_softc *sc;
 227                 int error;
 228
 229                 sprintf(param, "arg%d", i);
 230                 name = gctl_get_asciiparam(req, param);
 231                 if (name == NULL) {
 232                         gctl_error(req, "No 'arg%d' argument", i);
 233                         g_topology_unlock();
 234                         return;
 235                 }
 236                 sc = virstor_find_geom(cp, name);
 237                 LOG_MSG(LVL_INFO, "Stopping %s by the userland command",
 238                     sc->geom->name);
 239                 update_metadata(sc);
 240                 if ((error = virstor_geom_destroy(sc, TRUE, TRUE)) != 0) {
 241                         LOG_MSG(LVL_ERROR, "Cannot destroy %s: %d",
 242                             sc->geom->name, error);
 243                 }
 244         }
 245         g_topology_unlock();
 246 }
 247
 248 /*
 249  * "add" verb from userland - add new component(s) to the structure.
 250  * This will be done all at once in here, without going through the
 251  * .taste function for new components.
 252  */
 253 static void
 254 virstor_ctl_add(struct gctl_req *req, struct g_class *cp)
 255 {
 256         /* Note: while this is going on, I/O is being done on
 257          * the g_up and g_down threads. The idea is to make changes
 258          * to softc members in a way that can atomically activate
 259          * them all at once. */
 260         struct g_virstor_softc *sc;
 261         int *hardcode, *nargs;
 262         const char *geom_name;  /* geom to add a component to */
 263         struct g_consumer *fcp;
 264         struct g_virstor_bio_q *bq;
 265         u_int added;
 266         int error;
 267         int i;
 268
 269         nargs = gctl_get_paraml(req, "nargs", sizeof(*nargs));
 270         if (nargs == NULL) {
 271                 gctl_error(req, "Error fetching argument '%s'", "nargs");
 272                 return;
 273         }
 274         if (*nargs < 2) {
 275                 gctl_error(req, "Invalid number of arguments");
 276                 return;
 277         }
 278         hardcode = gctl_get_paraml(req, "hardcode", sizeof(*hardcode));
 279         if (hardcode == NULL) {
 280                 gctl_error(req, "Error fetching argument '%s'", "hardcode");
 281                 return;
 282         }
 283
 284         /* Find "our" geom */
 285         geom_name = gctl_get_asciiparam(req, "arg0");
 286         if (geom_name == NULL) {
 287                 gctl_error(req, "Error fetching argument '%s'", "geom_name (arg0)");
 288                 return;
 289         }
 290         sc = virstor_find_geom(cp, geom_name);
 291         if (sc == NULL) {
 292                 gctl_error(req, "Don't know anything about '%s'", geom_name);
 293                 return;
 294         }
 295
 296         if (virstor_valid_components(sc) != sc->n_components) {
 297                 LOG_MSG(LVL_ERROR, "Cannot add components to incomplete "
 298                     "virstor %s", sc->geom->name);
 299                 gctl_error(req, "Virstor %s is incomplete", sc->geom->name);
 300                 return;
 301         }
 302
 303         fcp = sc->components[0].gcons;
 304         added = 0;
 305         g_topology_lock();
 306         for (i = 1; i < *nargs; i++) {
 307                 struct g_virstor_metadata md;
 308                 char aname[8];
 309                 const char *prov_name;
 310                 struct g_provider *pp;
 311                 struct g_consumer *cp;
 312                 u_int nc;
 313                 u_int j;
 314
 315                 snprintf(aname, sizeof aname, "arg%d", i);
 316                 prov_name = gctl_get_asciiparam(req, aname);
 317                 if (prov_name == NULL) {
 318                         gctl_error(req, "Error fetching argument '%s'", aname);
 319                         g_topology_unlock();
 320                         return;
 321                 }
 322                 if (strncmp(prov_name, _PATH_DEV, sizeof(_PATH_DEV) - 1) == 0)
 323                         prov_name += sizeof(_PATH_DEV) - 1;
 324
 325                 pp = g_provider_by_name(prov_name);
 326                 if (pp == NULL) {
 327                         /* This is the most common error so be verbose about it */
 328                         if (added != 0) {
 329                                 gctl_error(req, "Invalid provider: '%s' (added"
 330                                     " %u components)", prov_name, added);
 331                                 update_metadata(sc);
 332                         } else {
 333                                 gctl_error(req, "Invalid provider: '%s'",
 334                                     prov_name);
 335                         }
 336                         g_topology_unlock();
 337                         return;
 338                 }
 339                 cp = g_new_consumer(sc->geom);
 340                 if (cp == NULL) {
 341                         gctl_error(req, "Cannot create consumer");
 342                         g_topology_unlock();
 343                         return;
 344                 }
 345                 error = g_attach(cp, pp);
 346                 if (error != 0) {
 347                         gctl_error(req, "Cannot attach a consumer to %s",
 348                             pp->name);
 349                         g_destroy_consumer(cp);
 350                         g_topology_unlock();
 351                         return;
 352                 }
 353                 if (fcp->acr != 0 || fcp->acw != 0 || fcp->ace != 0) {
 354                         error = g_access(cp, fcp->acr, fcp->acw, fcp->ace);
 355                         if (error != 0) {
 356                                 gctl_error(req, "Access request failed for %s",
 357                                     pp->name);
 358                                 g_destroy_consumer(cp);
 359                                 g_topology_unlock();
 360                                 return;
 361                         }
 362                 }
 363                 if (fcp->provider->sectorsize != pp->sectorsize) {
 364                         gctl_error(req, "Sector size doesn't fit for %s",
 365                             pp->name);
 366                         g_destroy_consumer(cp);
 367                         g_topology_unlock();
 368                         return;
 369                 }
 370                 for (j = 0; j < sc->n_components; j++) {
 371                         if (strcmp(sc->components[j].gcons->provider->name,
 372                             pp->name) == 0) {
 373                                 gctl_error(req, "Component %s already in %s",
 374                                     pp->name, sc->geom->name);
 375                                 g_destroy_consumer(cp);
 376                                 g_topology_unlock();
 377                                 return;
 378                         }
 379                 }
 380                 sc->components = realloc(sc->components,
 381                     sizeof(*sc->components) * (sc->n_components + 1),
 382                     M_GVIRSTOR, M_WAITOK);
 383
 384                 nc = sc->n_components;
 385                 sc->components[nc].gcons = cp;
 386                 sc->components[nc].sc = sc;
 387                 sc->components[nc].index = nc;
 388                 sc->components[nc].chunk_count = cp->provider->mediasize /
 389                     sc->chunk_size;
 390                 sc->components[nc].chunk_next = 0;
 391                 sc->components[nc].chunk_reserved = 0;
 392
 393                 if (sc->components[nc].chunk_count < 4) {
 394                         gctl_error(req, "Provider too small: %s",
 395                             cp->provider->name);
 396                         g_destroy_consumer(cp);
 397                         g_topology_unlock();
 398                         return;
 399                 }
 400                 fill_metadata(sc, &md, nc, *hardcode);
 401                 write_metadata(cp, &md);
 402                 /* The new component becomes visible when n_components is
 403                  * incremented */
 404                 sc->n_components++;
 405                 added++;
 406
 407         }
 408         /* This call to update_metadata() is critical. In case there's a
 409          * power failure in the middle of it and some components are updated
 410          * while others are not, there will be trouble on next .taste() iff
 411          * a non-updated component is detected first */
 412         update_metadata(sc);
 413         g_topology_unlock();
 414         LOG_MSG(LVL_INFO, "Added %d component(s) to %s", added,
 415             sc->geom->name);
 416         /* Fire off BIOs previously queued because there wasn't any
 417          * physical space left. If the BIOs still can't be satisfied
 418          * they will again be added to the end of the queue (during
 419          * which the mutex will be recursed) */
 420         bq = malloc(sizeof(*bq), M_GVIRSTOR, M_WAITOK);
 421         bq->bio = NULL;
 422         mtx_lock(&sc->delayed_bio_q_mtx);
 423         /* First, insert a sentinel to the queue end, so we don't
 424          * end up in an infinite loop if there's still no free
 425          * space available. */
 426         STAILQ_INSERT_TAIL(&sc->delayed_bio_q, bq, linkage);
 427         while (!STAILQ_EMPTY(&sc->delayed_bio_q)) {
 428                 bq = STAILQ_FIRST(&sc->delayed_bio_q);
 429                 if (bq->bio != NULL) {
 430                         g_virstor_start(bq->bio);
 431                         STAILQ_REMOVE_HEAD(&sc->delayed_bio_q, linkage);
 432                         free(bq, M_GVIRSTOR);
 433                 } else {
 434                         STAILQ_REMOVE_HEAD(&sc->delayed_bio_q, linkage);
 435                         free(bq, M_GVIRSTOR);
 436                         break;
 437                 }
 438         }
 439         mtx_unlock(&sc->delayed_bio_q_mtx);
 440
 441 }
 442
 443 /*
 444  * Find a geom handled by the class
 445  */
 446 static struct g_virstor_softc *
 447 virstor_find_geom(const struct g_class *cp, const char *name)
 448 {
 449         struct g_geom *gp;
 450
 451         LIST_FOREACH(gp, &cp->geom, geom) {
 452                 if (strcmp(name, gp->name) == 0)
 453                         return (gp->softc);
 454         }
 455         return (NULL);
 456 }
 457
 458 /*
 459  * Update metadata on all components to reflect the current state
 460  * of these fields:
 461  *    - chunk_next
 462  *    - flags
 463  *    - md_count
 464  * Expects things to be set up so write_metadata() can work, i.e.
 465  * the topology lock must be held.
 466  */
 467 static void
 468 update_metadata(struct g_virstor_softc *sc)
 469 {
 470         struct g_virstor_metadata md;
 471         int n;
 472
 473         if (virstor_valid_components(sc) != sc->n_components)
 474                 return; /* Incomplete device */
 475         LOG_MSG(LVL_DEBUG, "Updating metadata on components for %s",
 476             sc->geom->name);
 477         /* Update metadata on components */
 478         g_trace(G_T_TOPOLOGY, "%s(%s, %s)", __func__,
 479             sc->geom->class->name, sc->geom->name);
 480         g_topology_assert();
 481         for (n = 0; n < sc->n_components; n++) {
 482                 read_metadata(sc->components[n].gcons, &md);
 483                 md.chunk_next = sc->components[n].chunk_next;
 484                 md.flags = sc->components[n].flags;
 485                 md.md_count = sc->n_components;
 486                 write_metadata(sc->components[n].gcons, &md);
 487         }
 488 }
 489
 490 /*
 491  * Fills metadata (struct md) from information stored in softc and the nc'th
 492  * component of virstor
 493  */
 494 static void
 495 fill_metadata(struct g_virstor_softc *sc, struct g_virstor_metadata *md,
 496     u_int nc, u_int hardcode)
 497 {
 498         struct g_virstor_component *c;
 499
 500         bzero(md, sizeof *md);
 501         c = &sc->components[nc];
 502
 503         strncpy(md->md_magic, G_VIRSTOR_MAGIC, sizeof md->md_magic);
 504         md->md_version = G_VIRSTOR_VERSION;
 505         strncpy(md->md_name, sc->geom->name, sizeof md->md_name);
 506         md->md_id = sc->id;
 507         md->md_virsize = sc->virsize;
 508         md->md_chunk_size = sc->chunk_size;
 509         md->md_count = sc->n_components;
 510
 511         if (hardcode) {
 512                 strncpy(md->provider, c->gcons->provider->name,
 513                     sizeof md->provider);
 514         }
 515         md->no = nc;
 516         md->provsize = c->gcons->provider->mediasize;
 517         md->chunk_count = c->chunk_count;
 518         md->chunk_next = c->chunk_next;
 519         md->chunk_reserved = c->chunk_reserved;
 520         md->flags = c->flags;
 521 }
 522
 523 /*
 524  * Remove a component from virstor device.
 525  * Can only be done if the component is unallocated.
 526  */
 527 static void
 528 virstor_ctl_remove(struct gctl_req *req, struct g_class *cp)
 529 {
 530         /* As this is executed in parallel to I/O, operations on virstor
 531          * structures must be as atomic as possible. */
 532         struct g_virstor_softc *sc;
 533         int *nargs;
 534         const char *geom_name;
 535         u_int removed;
 536         int i;
 537
 538         nargs = gctl_get_paraml(req, "nargs", sizeof(*nargs));
 539         if (nargs == NULL) {
 540                 gctl_error(req, "Error fetching argument '%s'", "nargs");
 541                 return;
 542         }
 543         if (*nargs < 2) {
 544                 gctl_error(req, "Invalid number of arguments");
 545                 return;
 546         }
 547         /* Find "our" geom */
 548         geom_name = gctl_get_asciiparam(req, "arg0");
 549         if (geom_name == NULL) {
 550                 gctl_error(req, "Error fetching argument '%s'",
 551                     "geom_name (arg0)");
 552                 return;
 553         }
 554         sc = virstor_find_geom(cp, geom_name);
 555         if (sc == NULL) {
 556                 gctl_error(req, "Don't know anything about '%s'", geom_name);
 557                 return;
 558         }
 559
 560         if (virstor_valid_components(sc) != sc->n_components) {
 561                 LOG_MSG(LVL_ERROR, "Cannot remove components from incomplete "
 562                     "virstor %s", sc->geom->name);
 563                 gctl_error(req, "Virstor %s is incomplete", sc->geom->name);
 564                 return;
 565         }
 566
 567         removed = 0;
 568         for (i = 1; i < *nargs; i++) {
 569                 char param[8];
 570                 const char *prov_name;
 571                 int j, found;
 572                 struct g_virstor_component *newcomp, *compbak;
 573
 574                 sprintf(param, "arg%d", i);
 575                 prov_name = gctl_get_asciiparam(req, param);
 576                 if (prov_name == NULL) {
 577                         gctl_error(req, "Error fetching argument '%s'", param);
 578                         return;
 579                 }
 580                 if (strncmp(prov_name, _PATH_DEV, sizeof(_PATH_DEV) - 1) == 0)
 581                         prov_name += sizeof(_PATH_DEV) - 1;
 582
 583                 found = -1;
 584                 for (j = 0; j < sc->n_components; j++) {
 585                         if (strcmp(sc->components[j].gcons->provider->name,
 586                             prov_name) == 0) {
 587                                 found = j;
 588                                 break;
 589                         }
 590                 }
 591                 if (found == -1) {
 592                         LOG_MSG(LVL_ERROR, "No %s component in %s",
 593                             prov_name, sc->geom->name);
 594                         continue;
 595                 }
 596
 597                 compbak = sc->components;
 598                 newcomp = malloc(sc->n_components * sizeof(*sc->components),
 599                     M_GVIRSTOR, M_WAITOK | M_ZERO);
 600                 bcopy(sc->components, newcomp, found * sizeof(*sc->components));
 601                 bcopy(&sc->components[found + 1], newcomp + found,
 602                     found * sizeof(*sc->components));
 603                 if ((sc->components[j].flags & VIRSTOR_PROVIDER_ALLOCATED) != 0) {
 604                         LOG_MSG(LVL_ERROR, "Allocated provider %s cannot be "
 605                             "removed from %s",
 606                             prov_name, sc->geom->name);
 607                         free(newcomp, M_GVIRSTOR);
 608                         /* We'll consider this non-fatal error */
 609                         continue;
 610                 }
 611                 /* Renumerate unallocated components */
 612                 for (j = 0; j < sc->n_components-1; j++) {
 613                         if ((sc->components[j].flags &
 614                             VIRSTOR_PROVIDER_ALLOCATED) == 0) {
 615                                 sc->components[j].index = j;
 616                         }
 617                 }
 618                 /* This is the critical section. If a component allocation
 619                  * event happens while both variables are not yet set,
 620                  * there will be trouble. Something will panic on encountering
 621                  * NULL sc->components[x].gcomp member.
 622                  * Luckily, component allocation happens very rarely and
 623                  * removing components is an abnormal action in any case. */
 624                 sc->components = newcomp;
 625                 sc->n_components--;
 626                 /* End critical section */
 627
 628                 g_topology_lock();
 629                 if (clear_metadata(&compbak[found]) != 0) {
 630                         LOG_MSG(LVL_WARNING, "Trouble ahead: cannot clear "
 631                             "metadata on %s", prov_name);
 632                 }
 633                 g_detach(compbak[found].gcons);
 634                 g_destroy_consumer(compbak[found].gcons);
 635                 g_topology_unlock();
 636
 637                 free(compbak, M_GVIRSTOR);
 638
 639                 removed++;
 640         }
 641
 642         /* This call to update_metadata() is critical. In case there's a
 643          * power failure in the middle of it and some components are updated
 644          * while others are not, there will be trouble on next .taste() iff
 645          * a non-updated component is detected first */
 646         g_topology_lock();
 647         update_metadata(sc);
 648         g_topology_unlock();
 649         LOG_MSG(LVL_INFO, "Removed %d component(s) from %s", removed,
 650             sc->geom->name);
 651 }
 652
 653 /*
 654  * Clear metadata sector on component
 655  */
 656 static int
 657 clear_metadata(struct g_virstor_component *comp)
 658 {
 659         char *buf;
 660         int error;
 661
 662         LOG_MSG(LVL_INFO, "Clearing metadata on %s",
 663             comp->gcons->provider->name);
 664         g_topology_assert();
 665         error = g_access(comp->gcons, 0, 1, 0);
 666         if (error != 0)
 667                 return (error);
 668         buf = malloc(comp->gcons->provider->sectorsize, M_GVIRSTOR,
 669             M_WAITOK | M_ZERO);
 670         error = g_write_data(comp->gcons,
 671             comp->gcons->provider->mediasize -
 672             comp->gcons->provider->sectorsize,
 673             buf,
 674             comp->gcons->provider->sectorsize);
 675         free(buf, M_GVIRSTOR);
 676         g_access(comp->gcons, 0, -1, 0);
 677         return (error);
 678 }
 679
 680 /*
 681  * Destroy geom forcibly.
 682  */
 683 static int
 684 g_virstor_destroy_geom(struct gctl_req *req __unused, struct g_class *mp,
 685     struct g_geom *gp)
 686 {
 687         struct g_virstor_softc *sc;
 688         int exitval;
 689
 690         sc = gp->softc;
 691         KASSERT(sc != NULL, ("%s: NULL sc", __func__));
 692
 693         exitval = 0;
 694         LOG_MSG(LVL_DEBUG, "%s called for %s, sc=%p", __func__, gp->name,
 695             gp->softc);
 696
 697         if (sc != NULL) {
 698 #ifdef INVARIANTS
 699                 char *buf;
 700                 int error;
 701                 off_t off;
 702                 int isclean, count;
 703                 int n;
 704
 705                 LOG_MSG(LVL_INFO, "INVARIANTS detected");
 706                 LOG_MSG(LVL_INFO, "Verifying allocation "
 707                     "table for %s", sc->geom->name);
 708                 count = 0;
 709                 for (n = 0; n < sc->chunk_count; n++) {
 710                         if (sc->map[n].flags || VIRSTOR_MAP_ALLOCATED != 0)
 711                                 count++;
 712                 }
 713                 LOG_MSG(LVL_INFO, "Device %s has %d allocated chunks",
 714                     sc->geom->name, count);
 715                 n = off = count = 0;
 716                 isclean = 1;
 717                 if (virstor_valid_components(sc) != sc->n_components) {
 718                         /* This is a incomplete virstor device (not all
 719                          * components have been found) */
 720                         LOG_MSG(LVL_ERROR, "Device %s is incomplete",
 721                             sc->geom->name);
 722                         goto bailout;
 723                 }
 724                 error = g_access(sc->components[0].gcons, 1, 0, 0);
 725                 KASSERT(error == 0, ("%s: g_access failed (%d)", __func__,
 726                     error));
 727                 /* Compare the whole on-disk allocation table with what's
 728                  * currently in memory */
 729                 while (n < sc->chunk_count) {
 730                         buf = g_read_data(sc->components[0].gcons, off,
 731                             sc->sectorsize, &error);
 732                         KASSERT(buf != NULL, ("g_read_data returned NULL (%d) "
 733                             "for read at %jd", error, off));
 734                         if (bcmp(buf, &sc->map[n], sc->sectorsize) != 0) {
 735                                 LOG_MSG(LVL_ERROR, "ERROR in allocation table, "
 736                                     "entry %d, offset %jd", n, off);
 737                                 isclean = 0;
 738                                 count++;
 739                         }
 740                         n += sc->me_per_sector;
 741                         off += sc->sectorsize;
 742                         g_free(buf);
 743                 }
 744                 error = g_access(sc->components[0].gcons, -1, 0, 0);
 745                 KASSERT(error == 0, ("%s: g_access failed (%d) on exit",
 746                     __func__, error));
 747                 if (isclean != 1) {
 748                         LOG_MSG(LVL_ERROR, "ALLOCATION TABLE CORRUPTED FOR %s "
 749                             "(%d sectors don't match, max %zu allocations)",
 750                             sc->geom->name, count,
 751                             count * sc->me_per_sector);
 752                 } else {
 753                         LOG_MSG(LVL_INFO, "Allocation table ok for %s",
 754                             sc->geom->name);
 755                 }
 756 bailout:
 757 #endif
 758                 update_metadata(sc);
 759                 virstor_geom_destroy(sc, FALSE, FALSE);
 760                 exitval = EAGAIN;
 761         } else
 762                 exitval = 0;
 763         return (exitval);
 764 }
 765
 766 /*
 767  * Taste event (per-class callback)
 768  * Examines a provider and creates geom instances if needed
 769  */
 770 static struct g_geom *
 771 g_virstor_taste(struct g_class *mp, struct g_provider *pp, int flags)
 772 {
 773         struct g_virstor_metadata md;
 774         struct g_geom *gp;
 775         struct g_consumer *cp;
 776         struct g_virstor_softc *sc;
 777         int error;
 778
 779         g_trace(G_T_TOPOLOGY, "%s(%s, %s)", __func__, mp->name, pp->name);
 780         g_topology_assert();
 781         LOG_MSG(LVL_DEBUG, "Tasting %s", pp->name);
 782
 783         /* We need a dummy geom to attach a consumer to the given provider */
 784         gp = g_new_geomf(mp, "virstor:taste.helper");
 785         gp->start = (void *)invalid_call;       /* XXX: hacked up so the        */
 786         gp->access = (void *)invalid_call;      /* compiler doesn't complain.   */
 787         gp->orphan = (void *)invalid_call;      /* I really want these to fail. */
 788
 789         cp = g_new_consumer(gp);
 790         g_attach(cp, pp);
 791         error = read_metadata(cp, &md);
 792         g_detach(cp);
 793         g_destroy_consumer(cp);
 794         g_destroy_geom(gp);
 795
 796         if (error != 0)
 797                 return (NULL);
 798
 799         if (strcmp(md.md_magic, G_VIRSTOR_MAGIC) != 0)
 800                 return (NULL);
 801         if (md.md_version != G_VIRSTOR_VERSION) {
 802                 LOG_MSG(LVL_ERROR, "Kernel module version invalid "
 803                     "to handle %s (%s) : %d should be %d",
 804                     md.md_name, pp->name, md.md_version, G_VIRSTOR_VERSION);
 805                 return (NULL);
 806         }
 807         if (md.provsize != pp->mediasize)
 808                 return (NULL);
 809
 810         /* If the provider name is hardcoded, use the offered provider only
 811          * if it's been offered with its proper name (the one used in
 812          * the label command). */
 813         if (md.provider[0] != '\0' &&
 814             !g_compare_names(md.provider, pp->name))
 815                 return (NULL);
 816
 817         /* Iterate all geoms this class already knows about to see if a new
 818          * geom instance of this class needs to be created (in case the provider
 819          * is first from a (possibly) multi-consumer geom) or it just needs
 820          * to be added to an existing instance. */
 821         sc = NULL;
 822         gp = NULL;
 823         LIST_FOREACH(gp, &mp->geom, geom) {
 824                 sc = gp->softc;
 825                 if (sc == NULL)
 826                         continue;
 827                 if (strcmp(md.md_name, sc->geom->name) != 0)
 828                         continue;
 829                 if (md.md_id != sc->id)
 830                         continue;
 831                 break;
 832         }
 833         if (gp != NULL) { /* We found an existing geom instance; add to it */
 834                 LOG_MSG(LVL_INFO, "Adding %s to %s", pp->name, md.md_name);
 835                 error = add_provider_to_geom(sc, pp, &md);
 836                 if (error != 0) {
 837                         LOG_MSG(LVL_ERROR, "Error adding %s to %s (error %d)",
 838                             pp->name, md.md_name, error);
 839                         return (NULL);
 840                 }
 841         } else { /* New geom instance needs to be created */
 842                 gp = create_virstor_geom(mp, &md);
 843                 if (gp == NULL) {
 844                         LOG_MSG(LVL_ERROR, "Error creating new instance of "
 845                             "class %s: %s", mp->name, md.md_name);
 846                         LOG_MSG(LVL_DEBUG, "Error creating %s at %s",
 847                             md.md_name, pp->name);
 848                         return (NULL);
 849                 }
 850                 sc = gp->softc;
 851                 LOG_MSG(LVL_INFO, "Adding %s to %s (first found)", pp->name,
 852                     md.md_name);
 853                 error = add_provider_to_geom(sc, pp, &md);
 854                 if (error != 0) {
 855                         LOG_MSG(LVL_ERROR, "Error adding %s to %s (error %d)",
 856                             pp->name, md.md_name, error);
 857                         virstor_geom_destroy(sc, TRUE, FALSE);
 858                         return (NULL);
 859                 }
 860         }
 861
 862         return (gp);
 863 }
 864
 865 /*
 866  * Destroyes consumer passed to it in arguments. Used as a callback
 867  * on g_event queue.
 868  */
 869 static void
 870 delay_destroy_consumer(void *arg, int flags __unused)
 871 {
 872         struct g_consumer *c = arg;
 873         KASSERT(c != NULL, ("%s: invalid consumer", __func__));
 874         LOG_MSG(LVL_DEBUG, "Consumer %s destroyed with delay",
 875             c->provider->name);
 876         g_detach(c);
 877         g_destroy_consumer(c);
 878 }
 879
 880 /*
 881  * Remove a component (consumer) from geom instance; If it's the first
 882  * component being removed, orphan the provider to announce geom's being
 883  * dismantled
 884  */
 885 static void
 886 remove_component(struct g_virstor_softc *sc, struct g_virstor_component *comp,
 887     boolean_t delay)
 888 {
 889         struct g_consumer *c;
 890
 891         KASSERT(comp->gcons != NULL, ("Component with no consumer in %s",
 892             sc->geom->name));
 893         c = comp->gcons;
 894
 895         comp->gcons = NULL;
 896         KASSERT(c->provider != NULL, ("%s: no provider", __func__));
 897         LOG_MSG(LVL_DEBUG, "Component %s removed from %s", c->provider->name,
 898             sc->geom->name);
 899         if (sc->provider != NULL) {
 900                 /* Whither, GEOM? */
 901                 sc->provider->flags |= G_PF_WITHER;
 902                 g_orphan_provider(sc->provider, ENXIO);
 903                 sc->provider = NULL;
 904                 LOG_MSG(LVL_INFO, "Removing provider %s", sc->geom->name);
 905         }
 906
 907         if (c->acr > 0 || c->acw > 0 || c->ace > 0)
 908                 g_access(c, -c->acr, -c->acw, -c->ace);
 909         if (delay) {
 910                 /* Destroy consumer after it's tasted */
 911                 g_post_event(delay_destroy_consumer, c, M_WAITOK, NULL);
 912         } else {
 913                 g_detach(c);
 914                 g_destroy_consumer(c);
 915         }
 916 }
 917
 918 /*
 919  * Destroy geom - called internally
 920  * See g_virstor_destroy_geom for the other one
 921  */
 922 static int
 923 virstor_geom_destroy(struct g_virstor_softc *sc, boolean_t force,
 924     boolean_t delay)
 925 {
 926         struct g_provider *pp;
 927         struct g_geom *gp;
 928         int n;
 929
 930         g_topology_assert();
 931
 932         if (sc == NULL)
 933                 return (ENXIO);
 934
 935         pp = sc->provider;
 936         if (pp != NULL && (pp->acr != 0 || pp->acw != 0 || pp->ace != 0)) {
 937                 LOG_MSG(force ? LVL_WARNING : LVL_ERROR,
 938                     "Device %s is still open.", pp->name);
 939                 if (!force)
 940                         return (EBUSY);
 941         }
 942
 943         for (n = 0; n < sc->n_components; n++) {
 944                 if (sc->components[n].gcons != NULL)
 945                         remove_component(sc, &sc->components[n], delay);
 946         }
 947
 948         gp = sc->geom;
 949         gp->softc = NULL;
 950
 951         KASSERT(sc->provider == NULL, ("Provider still exists for %s",
 952             gp->name));
 953
 954         /* XXX: This might or might not work, since we're called with
 955          * the topology lock held. Also, it might panic the kernel if
 956          * the error'd BIO is in softupdates code. */
 957         mtx_lock(&sc->delayed_bio_q_mtx);
 958         while (!STAILQ_EMPTY(&sc->delayed_bio_q)) {
 959                 struct g_virstor_bio_q *bq;
 960                 bq = STAILQ_FIRST(&sc->delayed_bio_q);
 961                 bq->bio->bio_error = ENOSPC;
 962                 g_io_deliver(bq->bio, EIO);
 963                 STAILQ_REMOVE_HEAD(&sc->delayed_bio_q, linkage);
 964                 free(bq, M_GVIRSTOR);
 965         }
 966         mtx_unlock(&sc->delayed_bio_q_mtx);
 967         mtx_destroy(&sc->delayed_bio_q_mtx);
 968
 969         free(sc->map, M_GVIRSTOR);
 970         free(sc->components, M_GVIRSTOR);
 971         bzero(sc, sizeof *sc);
 972         free(sc, M_GVIRSTOR);
 973
 974         pp = LIST_FIRST(&gp->provider); /* We only offer one provider */
 975         if (pp == NULL || (pp->acr == 0 && pp->acw == 0 && pp->ace == 0))
 976                 LOG_MSG(LVL_DEBUG, "Device %s destroyed", gp->name);
 977
 978         g_wither_geom(gp, ENXIO);
 979
 980         return (0);
 981 }
 982
 983 /*
 984  * Utility function: read metadata & decode. Wants topology lock to be
 985  * held.
 986  */
 987 static int
 988 read_metadata(struct g_consumer *cp, struct g_virstor_metadata *md)
 989 {
 990         struct g_provider *pp;
 991         char *buf;
 992         int error;
 993
 994         g_topology_assert();
 995         error = g_access(cp, 1, 0, 0);
 996         if (error != 0)
 997                 return (error);
 998         pp = cp->provider;
 999         g_topology_unlock();
1000         buf = g_read_data(cp, pp->mediasize - pp->sectorsize, pp->sectorsize,
1001             &error);
1002         g_topology_lock();
1003         g_access(cp, -1, 0, 0);
1004         if (buf == NULL)
1005                 return (error);
1006
1007         virstor_metadata_decode(buf, md);
1008         g_free(buf);
1009
1010         return (0);
1011 }
1012
1013 /**
1014  * Utility function: encode & write metadata. Assumes topology lock is
1015  * held.
1016  *
1017  * There is no useful way of recovering from errors in this function,
1018  * not involving panicking the kernel. If the metadata cannot be written
1019  * the most we can do is notify the operator and hope he spots it and
1020  * replaces the broken drive.
1021  */
1022 static void
1023 write_metadata(struct g_consumer *cp, struct g_virstor_metadata *md)
1024 {
1025         struct g_provider *pp;
1026         char *buf;
1027         int error;
1028
1029         KASSERT(cp != NULL && md != NULL && cp->provider != NULL,
1030             ("Something's fishy in %s", __func__));
1031         LOG_MSG(LVL_DEBUG, "Writing metadata on %s", cp->provider->name);
1032         g_topology_assert();
1033         error = g_access(cp, 0, 1, 0);
1034         if (error != 0) {
1035                 LOG_MSG(LVL_ERROR, "g_access(0,1,0) failed for %s: %d",
1036                     cp->provider->name, error);
1037                 return;
1038         }
1039         pp = cp->provider;
1040
1041         buf = malloc(pp->sectorsize, M_GVIRSTOR, M_WAITOK);
1042         virstor_metadata_encode(md, buf);
1043         g_topology_unlock();
1044         error = g_write_data(cp, pp->mediasize - pp->sectorsize, buf,
1045             pp->sectorsize);
1046         g_topology_lock();
1047         g_access(cp, 0, -1, 0);
1048         free(buf, M_GVIRSTOR);
1049
1050         if (error != 0)
1051                 LOG_MSG(LVL_ERROR, "Error %d writing metadata to %s",
1052                     error, cp->provider->name);
1053 }
1054
1055 /*
1056  * Creates a new instance of this GEOM class, initialise softc
1057  */
1058 static struct g_geom *
1059 create_virstor_geom(struct g_class *mp, struct g_virstor_metadata *md)
1060 {
1061         struct g_geom *gp;
1062         struct g_virstor_softc *sc;
1063
1064         LOG_MSG(LVL_DEBUG, "Creating geom instance for %s (id=%u)",
1065             md->md_name, md->md_id);
1066
1067         if (md->md_count < 1 || md->md_chunk_size < 1 ||
1068             md->md_virsize < md->md_chunk_size) {
1069                 /* This is bogus configuration, and probably means data is
1070                  * somehow corrupted. Panic, maybe? */
1071                 LOG_MSG(LVL_ERROR, "Nonsensical metadata information for %s",
1072                     md->md_name);
1073                 return (NULL);
1074         }
1075
1076         /* Check if it's already created */
1077         LIST_FOREACH(gp, &mp->geom, geom) {
1078                 sc = gp->softc;
1079                 if (sc != NULL && strcmp(sc->geom->name, md->md_name) == 0) {
1080                         LOG_MSG(LVL_WARNING, "Geom %s already exists",
1081                             md->md_name);
1082                         if (sc->id != md->md_id) {
1083                                 LOG_MSG(LVL_ERROR,
1084                                     "Some stale or invalid components "
1085                                     "exist for virstor device named %s. "
1086                                     "You will need to <CLEAR> all stale "
1087                                     "components and maybe reconfigure "
1088                                     "the virstor device. Tune "
1089                                     "kern.geom.virstor.debug sysctl up "
1090                                     "for more information.",
1091                                     sc->geom->name);
1092                         }
1093                         return (NULL);
1094                 }
1095         }
1096         gp = g_new_geomf(mp, "%s", md->md_name);
1097         gp->softc = NULL; /* to circumevent races that test softc */
1098
1099         gp->start = g_virstor_start;
1100         gp->spoiled = g_virstor_orphan;
1101         gp->orphan = g_virstor_orphan;
1102         gp->access = g_virstor_access;
1103         gp->dumpconf = g_virstor_dumpconf;
1104
1105         sc = malloc(sizeof(*sc), M_GVIRSTOR, M_WAITOK | M_ZERO);
1106         sc->id = md->md_id;
1107         sc->n_components = md->md_count;
1108         sc->components = malloc(sizeof(struct g_virstor_component) * md->md_count,
1109             M_GVIRSTOR, M_WAITOK | M_ZERO);
1110         sc->chunk_size = md->md_chunk_size;
1111         sc->virsize = md->md_virsize;
1112         STAILQ_INIT(&sc->delayed_bio_q);
1113         mtx_init(&sc->delayed_bio_q_mtx, "gvirstor_delayed_bio_q_mtx",
1114             "gvirstor", MTX_DEF | MTX_RECURSE);
1115
1116         sc->geom = gp;
1117         sc->provider = NULL; /* virstor_check_and_run will create it */
1118         gp->softc = sc;
1119
1120         LOG_MSG(LVL_ANNOUNCE, "Device %s created", sc->geom->name);
1121
1122         return (gp);
1123 }
1124
1125 /*
1126  * Add provider to a GEOM class instance
1127  */
1128 static int
1129 add_provider_to_geom(struct g_virstor_softc *sc, struct g_provider *pp,
1130     struct g_virstor_metadata *md)
1131 {
1132         struct g_virstor_component *component;
1133         struct g_consumer *cp, *fcp;
1134         struct g_geom *gp;
1135         int error;
1136
1137         if (md->no >= sc->n_components)
1138                 return (EINVAL);
1139
1140         /* "Current" compontent */
1141         component = &(sc->components[md->no]);
1142         if (component->gcons != NULL)
1143                 return (EEXIST);
1144
1145         gp = sc->geom;
1146         fcp = LIST_FIRST(&gp->consumer);
1147
1148         cp = g_new_consumer(gp);
1149         error = g_attach(cp, pp);
1150
1151         if (error != 0) {
1152                 g_destroy_consumer(cp);
1153                 return (error);
1154         }
1155
1156         if (fcp != NULL) {
1157                 if (fcp->provider->sectorsize != pp->sectorsize) {
1158                         /* TODO: this can be made to work */
1159                         LOG_MSG(LVL_ERROR, "Provider %s of %s has invalid "
1160                             "sector size (%d)", pp->name, sc->geom->name,
1161                             pp->sectorsize);
1162                         return (EINVAL);
1163                 }
1164                 if (fcp->acr > 0 || fcp->acw || fcp->ace > 0) {
1165                         /* Replicate access permissions from first "live" consumer
1166                          * to the new one */
1167                         error = g_access(cp, fcp->acr, fcp->acw, fcp->ace);
1168                         if (error != 0) {
1169                                 g_detach(cp);
1170                                 g_destroy_consumer(cp);
1171                                 return (error);
1172                         }
1173                 }
1174         }
1175
1176         /* Bring up a new component */
1177         cp->private = component;
1178         component->gcons = cp;
1179         component->sc = sc;
1180         component->index = md->no;
1181         component->chunk_count = md->chunk_count;
1182         component->chunk_next = md->chunk_next;
1183         component->chunk_reserved = md->chunk_reserved;
1184         component->flags = md->flags;
1185
1186         LOG_MSG(LVL_DEBUG, "%s attached to %s", pp->name, sc->geom->name);
1187
1188         virstor_check_and_run(sc);
1189         return (0);
1190 }
1191
1192 /*
1193  * Check if everything's ready to create the geom provider & device entry,
1194  * create and start provider.
1195  * Called ultimately by .taste, from g_event thread
1196  */
1197 static void
1198 virstor_check_and_run(struct g_virstor_softc *sc)
1199 {
1200         off_t off;
1201         size_t n, count;
1202         int index;
1203         int error;
1204
1205         if (virstor_valid_components(sc) != sc->n_components)
1206                 return;
1207
1208         if (virstor_valid_components(sc) == 0) {
1209                 /* This is actually a candidate for panic() */
1210                 LOG_MSG(LVL_ERROR, "No valid components for %s?",
1211                     sc->provider->name);
1212                 return;
1213         }
1214
1215         sc->sectorsize = sc->components[0].gcons->provider->sectorsize;
1216
1217         /* Initialise allocation map from the first consumer */
1218         sc->chunk_count = sc->virsize / sc->chunk_size;
1219         if (sc->chunk_count * (off_t)sc->chunk_size != sc->virsize) {
1220                 LOG_MSG(LVL_WARNING, "Device %s truncated to %ju bytes",
1221                     sc->provider->name,
1222                     sc->chunk_count * (off_t)sc->chunk_size);
1223         }
1224         sc->map_size = sc->chunk_count * sizeof *(sc->map);
1225         /* The following allocation is in order of 4MB - 8MB */
1226         sc->map = malloc(sc->map_size, M_GVIRSTOR, M_WAITOK);
1227         KASSERT(sc->map != NULL, ("%s: Memory allocation error (%zu bytes) for %s",
1228             __func__, sc->map_size, sc->provider->name));
1229         sc->map_sectors = sc->map_size / sc->sectorsize;
1230
1231         count = 0;
1232         for (n = 0; n < sc->n_components; n++)
1233                 count += sc->components[n].chunk_count;
1234         LOG_MSG(LVL_INFO, "Device %s has %zu physical chunks and %zu virtual "
1235             "(%zu KB chunks)",
1236             sc->geom->name, count, sc->chunk_count, sc->chunk_size / 1024);
1237
1238         error = g_access(sc->components[0].gcons, 1, 0, 0);
1239         if (error != 0) {
1240                 LOG_MSG(LVL_ERROR, "Cannot acquire read access for %s to "
1241                     "read allocation map for %s",
1242                     sc->components[0].gcons->provider->name,
1243                     sc->geom->name);
1244                 return;
1245         }
1246         /* Read in the allocation map */
1247         LOG_MSG(LVL_DEBUG, "Reading map for %s from %s", sc->geom->name,
1248             sc->components[0].gcons->provider->name);
1249         off = count = n = 0;
1250         while (count < sc->map_size) {
1251                 struct g_virstor_map_entry *mapbuf;
1252                 size_t bs;
1253
1254                 bs = MIN(MAXPHYS, sc->map_size - count);
1255                 if (bs % sc->sectorsize != 0) {
1256                         /* Check for alignment errors */
1257                         bs = (bs / sc->sectorsize) * sc->sectorsize;
1258                         if (bs == 0)
1259                                 break;
1260                         LOG_MSG(LVL_ERROR, "Trouble: map is not sector-aligned "
1261                             "for %s on %s", sc->geom->name,
1262                             sc->components[0].gcons->provider->name);
1263                 }
1264                 mapbuf = g_read_data(sc->components[0].gcons, off, bs, &error);
1265                 if (mapbuf == NULL) {
1266                         free(sc->map, M_GVIRSTOR);
1267                         LOG_MSG(LVL_ERROR, "Error reading allocation map "
1268                             "for %s from %s (offset %ju) (error %d)",
1269                             sc->geom->name,
1270                             sc->components[0].gcons->provider->name,
1271                             off, error);
1272                         return;
1273                 }
1274
1275                 bcopy(mapbuf, &sc->map[n], bs);
1276                 off += bs;
1277                 count += bs;
1278                 n += bs / sizeof *(sc->map);
1279                 g_free(mapbuf);
1280         }
1281         g_access(sc->components[0].gcons, -1, 0, 0);
1282         LOG_MSG(LVL_DEBUG, "Read map for %s", sc->geom->name);
1283
1284         /* find first component with allocatable chunks */
1285         index = -1;
1286         for (n = 0; n < sc->n_components; n++) {
1287                 if (sc->components[n].chunk_next <
1288                     sc->components[n].chunk_count) {
1289                         index = n;
1290                         break;
1291                 }
1292         }
1293         if (index == -1)
1294                 /* not found? set it to the last component and handle it
1295                  * later */
1296                 index = sc->n_components - 1;
1297
1298         if (index >= sc->n_components - g_virstor_component_watermark - 1) {
1299                 LOG_MSG(LVL_WARNING, "Device %s running out of components "
1300                     "(%d/%u: %s)", sc->geom->name,
1301                     index+1,
1302                     sc->n_components,
1303                     sc->components[index].gcons->provider->name);
1304         }
1305         sc->curr_component = index;
1306
1307         if (sc->components[index].chunk_next >=
1308             sc->components[index].chunk_count - g_virstor_chunk_watermark) {
1309                 LOG_MSG(LVL_WARNING,
1310                     "Component %s of %s is running out of free space "
1311                     "(%u chunks left)",
1312                     sc->components[index].gcons->provider->name,
1313                     sc->geom->name, sc->components[index].chunk_count -
1314                     sc->components[index].chunk_next);
1315         }
1316
1317         sc->me_per_sector = sc->sectorsize / sizeof *(sc->map);
1318         if (sc->sectorsize % sizeof *(sc->map) != 0) {
1319                 LOG_MSG(LVL_ERROR,
1320                     "%s: Map entries don't fit exactly in a sector (%s)",
1321                     __func__, sc->geom->name);
1322                 return;
1323         }
1324
1325         /* Recalculate allocated chunks in components & at the same time
1326          * verify map data is sane. We could trust metadata on this, but
1327          * we want to make sure. */
1328         for (n = 0; n < sc->n_components; n++)
1329                 sc->components[n].chunk_next = sc->components[n].chunk_reserved;
1330
1331         for (n = 0; n < sc->chunk_count; n++) {
1332                 if (sc->map[n].provider_no >= sc->n_components ||
1333                         sc->map[n].provider_chunk >=
1334                         sc->components[sc->map[n].provider_no].chunk_count) {
1335                         LOG_MSG(LVL_ERROR, "%s: Invalid entry %u in map for %s",
1336                             __func__, (u_int)n, sc->geom->name);
1337                         LOG_MSG(LVL_ERROR, "%s: provider_no: %u, n_components: %u"
1338                             " provider_chunk: %u, chunk_count: %u", __func__,
1339                             sc->map[n].provider_no, sc->n_components,
1340                             sc->map[n].provider_chunk,
1341                             sc->components[sc->map[n].provider_no].chunk_count);
1342                         return;
1343                 }
1344                 if (sc->map[n].flags & VIRSTOR_MAP_ALLOCATED)
1345                         sc->components[sc->map[n].provider_no].chunk_next++;
1346         }
1347
1348         sc->provider = g_new_providerf(sc->geom, "virstor/%s",
1349             sc->geom->name);
1350
1351         sc->provider->sectorsize = sc->sectorsize;
1352         sc->provider->mediasize = sc->virsize;
1353         g_error_provider(sc->provider, 0);
1354
1355         LOG_MSG(LVL_INFO, "%s activated", sc->provider->name);
1356         LOG_MSG(LVL_DEBUG, "%s starting with current component %u, starting "
1357             "chunk %u", sc->provider->name, sc->curr_component,
1358             sc->components[sc->curr_component].chunk_next);
1359 }
1360
1361 /*
1362  * Returns count of active providers in this geom instance
1363  */
1364 static u_int
1365 virstor_valid_components(struct g_virstor_softc *sc)
1366 {
1367         unsigned int nc, i;
1368
1369         nc = 0;
1370         KASSERT(sc != NULL, ("%s: softc is NULL", __func__));
1371         KASSERT(sc->components != NULL, ("%s: sc->components is NULL", __func__));
1372         for (i = 0; i < sc->n_components; i++)
1373                 if (sc->components[i].gcons != NULL)
1374                         nc++;
1375         return (nc);
1376 }
1377
1378 /*
1379  * Called when the consumer gets orphaned (?)
1380  */
1381 static void
1382 g_virstor_orphan(struct g_consumer *cp)
1383 {
1384         struct g_virstor_softc *sc;
1385         struct g_virstor_component *comp;
1386         struct g_geom *gp;
1387
1388         g_topology_assert();
1389         gp = cp->geom;
1390         sc = gp->softc;
1391         if (sc == NULL)
1392                 return;
1393
1394         comp = cp->private;
1395         KASSERT(comp != NULL, ("%s: No component in private part of consumer",
1396             __func__));
1397         remove_component(sc, comp, FALSE);
1398         if (virstor_valid_components(sc) == 0)
1399                 virstor_geom_destroy(sc, TRUE, FALSE);
1400 }
1401
1402 /*
1403  * Called to notify geom when it's been opened, and for what intent
1404  */
1405 static int
1406 g_virstor_access(struct g_provider *pp, int dr, int dw, int de)
1407 {
1408         struct g_consumer *c;
1409         struct g_virstor_softc *sc;
1410         struct g_geom *gp;
1411         int error;
1412
1413         KASSERT(pp != NULL, ("%s: NULL provider", __func__));
1414         gp = pp->geom;
1415         KASSERT(gp != NULL, ("%s: NULL geom", __func__));
1416         sc = gp->softc;
1417
1418         if (sc == NULL) {
1419                 /* It seems that .access can be called with negative dr,dw,dx
1420                  * in this case but I want to check for myself */
1421                 LOG_MSG(LVL_WARNING, "access(%d, %d, %d) for %s",
1422                     dr, dw, de, pp->name);
1423                 /* This should only happen when geom is withered so
1424                  * allow only negative requests */
1425                 KASSERT(dr <= 0 && dw <= 0 && de <= 0,
1426                     ("%s: Positive access for %s", __func__, pp->name));
1427                 if (pp->acr + dr == 0 && pp->acw + dw == 0 && pp->ace + de == 0)
1428                         LOG_MSG(LVL_DEBUG, "Device %s definitely destroyed",
1429                             pp->name);
1430                 return (0);
1431         }
1432
1433         /* Grab an exclusive bit to propagate on our consumers on first open */
1434         if (pp->acr == 0 && pp->acw == 0 && pp->ace == 0)
1435                 de++;
1436         /* ... drop it on close */
1437         if (pp->acr + dr == 0 && pp->acw + dw == 0 && pp->ace + de == 0) {
1438                 de--;
1439                 update_metadata(sc);    /* Writes statistical information */
1440         }
1441
1442         error = ENXIO;
1443         LIST_FOREACH(c, &gp->consumer, consumer) {
1444                 KASSERT(c != NULL, ("%s: consumer is NULL", __func__));
1445                 error = g_access(c, dr, dw, de);
1446                 if (error != 0) {
1447                         struct g_consumer *c2;
1448
1449                         /* Backout earlier changes */
1450                         LIST_FOREACH(c2, &gp->consumer, consumer) {
1451                                 if (c2 == c) /* all eariler components fixed */
1452                                         return (error);
1453                                 g_access(c2, -dr, -dw, -de);
1454                         }
1455                 }
1456         }
1457
1458         return (error);
1459 }
1460
1461 /*
1462  * Generate XML dump of current state
1463  */
1464 static void
1465 g_virstor_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp,
1466     struct g_consumer *cp, struct g_provider *pp)
1467 {
1468         struct g_virstor_softc *sc;
1469
1470         g_topology_assert();
1471         sc = gp->softc;
1472
1473         if (sc == NULL || pp != NULL)
1474                 return;
1475
1476         if (cp != NULL) {
1477                 /* For each component */
1478                 struct g_virstor_component *comp;
1479
1480                 comp = cp->private;
1481                 if (comp == NULL)
1482                         return;
1483                 sbuf_printf(sb, "%s<ComponentIndex>%u</ComponentIndex>\n",
1484                     indent, comp->index);
1485                 sbuf_printf(sb, "%s<ChunkCount>%u</ChunkCount>\n",
1486                     indent, comp->chunk_count);
1487                 sbuf_printf(sb, "%s<ChunksUsed>%u</ChunksUsed>\n",
1488                     indent, comp->chunk_next);
1489                 sbuf_printf(sb, "%s<ChunksReserved>%u</ChunksReserved>\n",
1490                     indent, comp->chunk_reserved);
1491                 sbuf_printf(sb, "%s<StorageFree>%u%%</StorageFree>\n",
1492                     indent,
1493                     comp->chunk_next > 0 ? 100 -
1494                     ((comp->chunk_next + comp->chunk_reserved) * 100) /
1495                     comp->chunk_count : 100);
1496         } else {
1497                 /* For the whole thing */
1498                 u_int count, used, i;
1499                 off_t size;
1500
1501                 count = used = size = 0;
1502                 for (i = 0; i < sc->n_components; i++) {
1503                         if (sc->components[i].gcons != NULL) {
1504                                 count += sc->components[i].chunk_count;
1505                                 used += sc->components[i].chunk_next +
1506                                     sc->components[i].chunk_reserved;
1507                                 size += sc->components[i].gcons->
1508                                     provider->mediasize;
1509                         }
1510                 }
1511
1512                 sbuf_printf(sb, "%s<Status>"
1513                     "Components=%u, Online=%u</Status>\n", indent,
1514                     sc->n_components, virstor_valid_components(sc));
1515                 sbuf_printf(sb, "%s<State>%u%% physical free</State>\n",
1516                     indent, 100-(used * 100) / count);
1517                 sbuf_printf(sb, "%s<ChunkSize>%zu</ChunkSize>\n", indent,
1518                     sc->chunk_size);
1519                 sbuf_printf(sb, "%s<PhysicalFree>%u%%</PhysicalFree>\n",
1520                     indent, used > 0 ? 100 - (used * 100) / count : 100);
1521                 sbuf_printf(sb, "%s<ChunkPhysicalCount>%u</ChunkPhysicalCount>\n",
1522                     indent, count);
1523                 sbuf_printf(sb, "%s<ChunkVirtualCount>%zu</ChunkVirtualCount>\n",
1524                     indent, sc->chunk_count);
1525                 sbuf_printf(sb, "%s<PhysicalBacking>%zu%%</PhysicalBacking>\n",
1526                     indent,
1527                     (count * 100) / sc->chunk_count);
1528                 sbuf_printf(sb, "%s<PhysicalBackingSize>%jd</PhysicalBackingSize>\n",
1529                     indent, size);
1530                 sbuf_printf(sb, "%s<VirtualSize>%jd</VirtualSize>\n", indent,
1531                     sc->virsize);
1532         }
1533 }
1534
1535 /*
1536  * GEOM .done handler
1537  * Can't use standard handler because one requested IO may
1538  * fork into additional data IOs
1539  */
1540 static void
1541 g_virstor_done(struct bio *b)
1542 {
1543         struct g_virstor_softc *sc;
1544         struct bio *parent_b;
1545
1546         parent_b = b->bio_parent;
1547         sc = parent_b->bio_to->geom->softc;
1548
1549         if (b->bio_error != 0) {
1550                 LOG_MSG(LVL_ERROR, "Error %d for offset=%ju, length=%ju, %s",
1551                     b->bio_error, b->bio_offset, b->bio_length,
1552                     b->bio_to->name);
1553                 if (parent_b->bio_error == 0)
1554                         parent_b->bio_error = b->bio_error;
1555         }
1556
1557         parent_b->bio_inbed++;
1558         parent_b->bio_completed += b->bio_completed;
1559
1560         if (parent_b->bio_children == parent_b->bio_inbed) {
1561                 parent_b->bio_completed = parent_b->bio_length;
1562                 g_io_deliver(parent_b, parent_b->bio_error);
1563         }
1564         g_destroy_bio(b);
1565 }
1566
1567 /*
1568  * I/O starts here
1569  * Called in g_down thread
1570  */
1571 static void
1572 g_virstor_start(struct bio *b)
1573 {
1574         struct g_virstor_softc *sc;
1575         struct g_virstor_component *comp;
1576         struct bio *cb;
1577         struct g_provider *pp;
1578         char *addr;
1579         off_t offset, length;
1580         struct bio_queue_head bq;
1581         size_t chunk_size;      /* cached for convenience */
1582         u_int count;
1583
1584         pp = b->bio_to;
1585         sc = pp->geom->softc;
1586         KASSERT(sc != NULL, ("%s: no softc (error=%d, device=%s)", __func__,
1587             b->bio_to->error, b->bio_to->name));
1588
1589         LOG_REQ(LVL_MOREDEBUG, b, "%s", __func__);
1590
1591         switch (b->bio_cmd) {
1592         case BIO_READ:
1593         case BIO_WRITE:
1594         case BIO_DELETE:
1595                 break;
1596         default:
1597                 g_io_deliver(b, EOPNOTSUPP);
1598                 return;
1599         }
1600
1601         LOG_MSG(LVL_DEBUG2, "BIO arrived, size=%ju", b->bio_length);
1602         bioq_init(&bq);
1603
1604         chunk_size = sc->chunk_size;
1605         addr = b->bio_data;
1606         offset = b->bio_offset; /* virtual offset and length */
1607         length = b->bio_length;
1608
1609         while (length > 0) {
1610                 size_t chunk_index, in_chunk_offset, in_chunk_length;
1611                 struct virstor_map_entry *me;
1612
1613                 chunk_index = offset / chunk_size; /* round downwards */
1614                 in_chunk_offset = offset % chunk_size;
1615                 in_chunk_length = min(length, chunk_size - in_chunk_offset);
1616                 LOG_MSG(LVL_DEBUG, "Mapped %s(%ju, %ju) to (%zu,%zu,%zu)",
1617                     b->bio_cmd == BIO_READ ? "R" : "W",
1618                     offset, length,
1619                     chunk_index, in_chunk_offset, in_chunk_length);
1620                 me = &sc->map[chunk_index];
1621
1622                 if (b->bio_cmd == BIO_READ || b->bio_cmd == BIO_DELETE) {
1623                         if ((me->flags & VIRSTOR_MAP_ALLOCATED) == 0) {
1624                                 /* Reads from unallocated chunks return zeroed
1625                                  * buffers */
1626                                 if (b->bio_cmd == BIO_READ)
1627                                         bzero(addr, in_chunk_length);
1628                         } else {
1629                                 comp = &sc->components[me->provider_no];
1630
1631                                 cb = g_clone_bio(b);
1632                                 if (cb == NULL) {
1633                                         bioq_dismantle(&bq);
1634                                         if (b->bio_error == 0)
1635                                                 b->bio_error = ENOMEM;
1636                                         g_io_deliver(b, b->bio_error);
1637                                         return;
1638                                 }
1639                                 cb->bio_to = comp->gcons->provider;
1640                                 cb->bio_done = g_virstor_done;
1641                                 cb->bio_offset =
1642                                     (off_t)me->provider_chunk * (off_t)chunk_size
1643                                     + in_chunk_offset;
1644                                 cb->bio_length = in_chunk_length;
1645                                 cb->bio_data = addr;
1646                                 cb->bio_caller1 = comp;
1647                                 bioq_disksort(&bq, cb);
1648                         }
1649                 } else { /* handle BIO_WRITE */
1650                         KASSERT(b->bio_cmd == BIO_WRITE,
1651                             ("%s: Unknown command %d", __func__,
1652                             b->bio_cmd));
1653
1654                         if ((me->flags & VIRSTOR_MAP_ALLOCATED) == 0) {
1655                                 /* We have a virtual chunk, represented by
1656                                  * the "me" entry, but it's not yet allocated
1657                                  * (tied to) a physical chunk. So do it now. */
1658                                 struct virstor_map_entry *data_me;
1659                                 u_int phys_chunk, comp_no;
1660                                 off_t s_offset;
1661                                 int error;
1662
1663                                 error = allocate_chunk(sc, &comp, &comp_no,
1664                                     &phys_chunk);
1665                                 if (error != 0) {
1666                                         /* We cannot allocate a physical chunk
1667                                          * to satisfy this request, so we'll
1668                                          * delay it to when we can...
1669                                          * XXX: this will prevent the fs from
1670                                          * being umounted! */
1671                                         struct g_virstor_bio_q *biq;
1672                                         biq = malloc(sizeof *biq, M_GVIRSTOR,
1673                                             M_NOWAIT);
1674                                         if (biq == NULL) {
1675                                                 bioq_dismantle(&bq);
1676                                                 if (b->bio_error == 0)
1677                                                         b->bio_error = ENOMEM;
1678                                                 g_io_deliver(b, b->bio_error);
1679                                                 return;
1680                                         }
1681                                         biq->bio = b;
1682                                         mtx_lock(&sc->delayed_bio_q_mtx);
1683                                         STAILQ_INSERT_TAIL(&sc->delayed_bio_q,
1684                                             biq, linkage);
1685                                         mtx_unlock(&sc->delayed_bio_q_mtx);
1686                                         LOG_MSG(LVL_WARNING, "Delaying BIO "
1687                                             "(size=%ju) until free physical "
1688                                             "space can be found on %s",
1689                                             b->bio_length,
1690                                             sc->provider->name);
1691                                         return;
1692                                 }
1693                                 LOG_MSG(LVL_DEBUG, "Allocated chunk %u on %s "
1694                                     "for %s",
1695                                     phys_chunk,
1696                                     comp->gcons->provider->name,
1697                                     sc->provider->name);
1698
1699                                 me->provider_no = comp_no;
1700                                 me->provider_chunk = phys_chunk;
1701                                 me->flags |= VIRSTOR_MAP_ALLOCATED;
1702
1703                                 cb = g_clone_bio(b);
1704                                 if (cb == NULL) {
1705                                         me->flags &= ~VIRSTOR_MAP_ALLOCATED;
1706                                         me->provider_no = 0;
1707                                         me->provider_chunk = 0;
1708                                         bioq_dismantle(&bq);
1709                                         if (b->bio_error == 0)
1710                                                 b->bio_error = ENOMEM;
1711                                         g_io_deliver(b, b->bio_error);
1712                                         return;
1713                                 }
1714
1715                                 /* The allocation table is stored continuously
1716                                  * at the start of the drive. We need to
1717                                  * calculate the offset of the sector that holds
1718                                  * this map entry both on the drive and in the
1719                                  * map array.
1720                                  * sc_offset will end up pointing to the drive
1721                                  * sector. */
1722                                 s_offset = chunk_index * sizeof *me;
1723                                 s_offset = (s_offset / sc->sectorsize) *
1724                                     sc->sectorsize;
1725
1726                                 /* data_me points to map entry sector
1727                                  * in memory (analoguos to offset) */
1728                                 data_me = &sc->map[(chunk_index /
1729                                     sc->me_per_sector) * sc->me_per_sector];
1730
1731                                 /* Commit sector with map entry to storage */
1732                                 cb->bio_to = sc->components[0].gcons->provider;
1733                                 cb->bio_done = g_virstor_done;
1734                                 cb->bio_offset = s_offset;
1735                                 cb->bio_data = (char *)data_me;
1736                                 cb->bio_length = sc->sectorsize;
1737                                 cb->bio_caller1 = &sc->components[0];
1738                                 bioq_disksort(&bq, cb);
1739                         }
1740
1741                         comp = &sc->components[me->provider_no];
1742                         cb = g_clone_bio(b);
1743                         if (cb == NULL) {
1744                                 bioq_dismantle(&bq);
1745                                 if (b->bio_error == 0)
1746                                         b->bio_error = ENOMEM;
1747                                 g_io_deliver(b, b->bio_error);
1748                                 return;
1749                         }
1750                         /* Finally, handle the data */
1751                         cb->bio_to = comp->gcons->provider;
1752                         cb->bio_done = g_virstor_done;
1753                         cb->bio_offset = (off_t)me->provider_chunk*(off_t)chunk_size +
1754                             in_chunk_offset;
1755                         cb->bio_length = in_chunk_length;
1756                         cb->bio_data = addr;
1757                         cb->bio_caller1 = comp;
1758                         bioq_disksort(&bq, cb);
1759                 }
1760                 addr += in_chunk_length;
1761                 length -= in_chunk_length;
1762                 offset += in_chunk_length;
1763         }
1764
1765         /* Fire off bio's here */
1766         count = 0;
1767         for (cb = bioq_first(&bq); cb != NULL; cb = bioq_first(&bq)) {
1768                 bioq_remove(&bq, cb);
1769                 LOG_REQ(LVL_MOREDEBUG, cb, "Firing request");
1770                 comp = cb->bio_caller1;
1771                 cb->bio_caller1 = NULL;
1772                 LOG_MSG(LVL_DEBUG, " firing bio, offset=%ju, length=%ju",
1773                     cb->bio_offset, cb->bio_length);
1774                 g_io_request(cb, comp->gcons);
1775                 count++;
1776         }
1777         if (count == 0) { /* We handled everything locally */
1778                 b->bio_completed = b->bio_length;
1779                 g_io_deliver(b, 0);
1780         }
1781
1782 }
1783
1784 /*
1785  * Allocate a chunk from a physical provider. Returns physical component,
1786  * chunk index relative to the component and the component's index.
1787  */
1788 static int
1789 allocate_chunk(struct g_virstor_softc *sc, struct g_virstor_component **comp,
1790     u_int *comp_no_p, u_int *chunk)
1791 {
1792         u_int comp_no;
1793
1794         KASSERT(sc->curr_component < sc->n_components,
1795             ("%s: Invalid curr_component: %u",  __func__, sc->curr_component));
1796
1797         comp_no = sc->curr_component;
1798         *comp = &sc->components[comp_no];
1799         dump_component(*comp);
1800         if ((*comp)->chunk_next >= (*comp)->chunk_count) {
1801                 /* This component is full. Allocate next component */
1802                 if (comp_no >= sc->n_components-1) {
1803                         LOG_MSG(LVL_ERROR, "All physical space allocated for %s",
1804                             sc->geom->name);
1805                         return (-1);
1806                 }
1807                 (*comp)->flags &= ~VIRSTOR_PROVIDER_CURRENT;
1808                 sc->curr_component = ++comp_no;
1809
1810                 *comp = &sc->components[comp_no];
1811                 if (comp_no >= sc->n_components - g_virstor_component_watermark-1)
1812                         LOG_MSG(LVL_WARNING, "Device %s running out of components "
1813                             "(switching to %u/%u: %s)", sc->geom->name,
1814                             comp_no+1, sc->n_components,
1815                             (*comp)->gcons->provider->name);
1816                 /* Take care not to overwrite reserved chunks */
1817                 if ( (*comp)->chunk_reserved > 0 &&
1818                     (*comp)->chunk_next < (*comp)->chunk_reserved)
1819                         (*comp)->chunk_next = (*comp)->chunk_reserved;
1820
1821                 (*comp)->flags |=
1822                     VIRSTOR_PROVIDER_ALLOCATED | VIRSTOR_PROVIDER_CURRENT;
1823                 dump_component(*comp);
1824                 *comp_no_p = comp_no;
1825                 *chunk = (*comp)->chunk_next++;
1826         } else {
1827                 *comp_no_p = comp_no;
1828                 *chunk = (*comp)->chunk_next++;
1829         }
1830         return (0);
1831 }
1832
1833 /* Dump a component */
1834 static void
1835 dump_component(struct g_virstor_component *comp)
1836 {
1837
1838         if (g_virstor_debug < LVL_DEBUG2)
1839                 return;
1840         printf("Component %d: %s\n", comp->index, comp->gcons->provider->name);
1841         printf("  chunk_count: %u\n", comp->chunk_count);
1842         printf("   chunk_next: %u\n", comp->chunk_next);
1843         printf("        flags: %u\n", comp->flags);
1844 }
1845
1846 #if 0
1847 /* Dump a map entry */
1848 static void
1849 dump_me(struct virstor_map_entry *me, unsigned int nr)
1850 {
1851         if (g_virstor_debug < LVL_DEBUG)
1852                 return;
1853         printf("VIRT. CHUNK #%d: ", nr);
1854         if ((me->flags & VIRSTOR_MAP_ALLOCATED) == 0)
1855                 printf("(unallocated)\n");
1856         else
1857                 printf("allocated at provider %u, provider_chunk %u\n",
1858                     me->provider_no, me->provider_chunk);
1859 }
1860 #endif
1861
1862 /*
1863  * Dismantle bio_queue and destroy its components
1864  */
1865 static void
1866 bioq_dismantle(struct bio_queue_head *bq)
1867 {
1868         struct bio *b;
1869
1870         for (b = bioq_first(bq); b != NULL; b = bioq_first(bq)) {
1871                 bioq_remove(bq, b);
1872                 g_destroy_bio(b);
1873         }
1874 }
1875
1876 /*
1877  * The function that shouldn't be called.
1878  * When this is called, the stack is already garbled because of
1879  * argument mismatch. There's nothing to do now but panic, which is
1880  * accidentally the whole purpose of this function.
1881  * Motivation: to guard from accidentally calling geom methods when
1882  * they shouldn't be called. (see g_..._taste)
1883  */
1884 static void
1885 invalid_call(void)
1886 {
1887         panic("invalid_call() has just been called. Something's fishy here.");
1888 }
1889
1890 DECLARE_GEOM_CLASS(g_virstor_class, g_virstor); /* Let there be light */