sys/geom/virstor/g_virstor.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   3  *
   4  * Copyright (c) 2006-2007 Ivan Voras <ivoras@freebsd.org>
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  */
  28
  29 /* Implementation notes:
  30  * - "Components" are wrappers around providers that make up the
  31  *   virtual storage (i.e. a virstor has "physical" components)
  32  */
  33
  34 #include <sys/cdefs.h>
  35 __FBSDID("$FreeBSD$");
  36
  37 #include <sys/param.h>
  38 #include <sys/systm.h>
  39 #include <sys/kernel.h>
  40 #include <sys/module.h>
  41 #include <sys/lock.h>
  42 #include <sys/mutex.h>
  43 #include <sys/sx.h>
  44 #include <sys/bio.h>
  45 #include <sys/sbuf.h>
  46 #include <sys/sysctl.h>
  47 #include <sys/malloc.h>
  48 #include <sys/time.h>
  49 #include <sys/proc.h>
  50 #include <sys/kthread.h>
  51 #include <sys/mutex.h>
  52 #include <vm/uma.h>
  53 #include <geom/geom.h>
  54
  55 #include <geom/virstor/g_virstor.h>
  56 #include <geom/virstor/g_virstor_md.h>
  57
  58 FEATURE(g_virstor, "GEOM virtual storage support");
  59
  60 /* Declare malloc(9) label */
  61 static MALLOC_DEFINE(M_GVIRSTOR, "gvirstor", "GEOM_VIRSTOR Data");
  62
  63 /* GEOM class methods */
  64 static g_init_t g_virstor_init;
  65 static g_fini_t g_virstor_fini;
  66 static g_taste_t g_virstor_taste;
  67 static g_ctl_req_t g_virstor_config;
  68 static g_ctl_destroy_geom_t g_virstor_destroy_geom;
  69
  70 /* Declare & initialize class structure ("geom class") */
  71 struct g_class g_virstor_class = {
  72         .name =         G_VIRSTOR_CLASS_NAME,
  73         .version =      G_VERSION,
  74         .init =         g_virstor_init,
  75         .fini =         g_virstor_fini,
  76         .taste =        g_virstor_taste,
  77         .ctlreq =       g_virstor_config,
  78         .destroy_geom = g_virstor_destroy_geom
  79         /* The .dumpconf and the rest are only usable for a geom instance, so
  80          * they will be set when such instance is created. */
  81 };
  82
  83 /* Declare sysctl's and loader tunables */
  84 SYSCTL_DECL(_kern_geom);
  85 static SYSCTL_NODE(_kern_geom, OID_AUTO, virstor, CTLFLAG_RW, 0,
  86     "GEOM_GVIRSTOR information");
  87
  88 static u_int g_virstor_debug = 2; /* XXX: lower to 2 when released to public */
  89 SYSCTL_UINT(_kern_geom_virstor, OID_AUTO, debug, CTLFLAG_RWTUN, &g_virstor_debug,
  90     0, "Debug level (2=production, 5=normal, 15=excessive)");
  91
  92 static u_int g_virstor_chunk_watermark = 100;
  93 SYSCTL_UINT(_kern_geom_virstor, OID_AUTO, chunk_watermark, CTLFLAG_RWTUN,
  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 SYSCTL_UINT(_kern_geom_virstor, OID_AUTO, component_watermark, CTLFLAG_RWTUN,
  99     &g_virstor_component_watermark, 0,
 100     "Minimum number of free components before issuing administrative warning");
 101
 102 static int read_metadata(struct g_consumer *, struct g_virstor_metadata *);
 103 static void write_metadata(struct g_consumer *, struct g_virstor_metadata *);
 104 static int clear_metadata(struct g_virstor_component *);
 105 static int add_provider_to_geom(struct g_virstor_softc *, struct g_provider *,
 106     struct g_virstor_metadata *);
 107 static struct g_geom *create_virstor_geom(struct g_class *,
 108     struct g_virstor_metadata *);
 109 static void virstor_check_and_run(struct g_virstor_softc *);
 110 static u_int virstor_valid_components(struct g_virstor_softc *);
 111 static int virstor_geom_destroy(struct g_virstor_softc *, boolean_t,
 112     boolean_t);
 113 static void remove_component(struct g_virstor_softc *,
 114     struct g_virstor_component *, boolean_t);
 115 static void bioq_dismantle(struct bio_queue_head *);
 116 static int allocate_chunk(struct g_virstor_softc *,
 117     struct g_virstor_component **, u_int *, u_int *);
 118 static void delay_destroy_consumer(void *, int);
 119 static void dump_component(struct g_virstor_component *comp);
 120 #if 0
 121 static void dump_me(struct virstor_map_entry *me, unsigned int nr);
 122 #endif
 123
 124 static void virstor_ctl_stop(struct gctl_req *, struct g_class *);
 125 static void virstor_ctl_add(struct gctl_req *, struct g_class *);
 126 static void virstor_ctl_remove(struct gctl_req *, struct g_class *);
 127 static struct g_virstor_softc * virstor_find_geom(const struct g_class *,
 128     const char *);
 129 static void update_metadata(struct g_virstor_softc *);
 130 static void fill_metadata(struct g_virstor_softc *, struct g_virstor_metadata *,
 131     u_int, u_int);
 132
 133 static void g_virstor_orphan(struct g_consumer *);
 134 static int g_virstor_access(struct g_provider *, int, int, int);
 135 static void g_virstor_start(struct bio *);
 136 static void g_virstor_dumpconf(struct sbuf *, const char *, struct g_geom *,
 137     struct g_consumer *, struct g_provider *);
 138 static void g_virstor_done(struct bio *);
 139
 140 static void invalid_call(void);
 141 /*
 142  * Initialise GEOM class (per-class callback)
 143  */
 144 static void
 145 g_virstor_init(struct g_class *mp __unused)
 146 {
 147
 148         /* Catch map struct size mismatch at compile time; Map entries must
 149          * fit into MAXPHYS exactly, with no wasted space. */
 150         CTASSERT(VIRSTOR_MAP_BLOCK_ENTRIES*VIRSTOR_MAP_ENTRY_SIZE == MAXPHYS);
 151
 152         /* Init UMA zones, TAILQ's, other global vars */
 153 }
 154
 155 /*
 156  * Finalise GEOM class (per-class callback)
 157  */
 158 static void
 159 g_virstor_fini(struct g_class *mp __unused)
 160 {
 161
 162         /* Deinit UMA zones & global vars */
 163 }
 164
 165 /*
 166  * Config (per-class callback)
 167  */
 168 static void
 169 g_virstor_config(struct gctl_req *req, struct g_class *cp, char const *verb)
 170 {
 171         uint32_t *version;
 172
 173         g_topology_assert();
 174
 175         version = gctl_get_paraml(req, "version", sizeof(*version));
 176         if (version == NULL) {
 177                 gctl_error(req, "Failed to get 'version' argument");
 178                 return;
 179         }
 180         if (*version != G_VIRSTOR_VERSION) {
 181                 gctl_error(req, "Userland and kernel versions out of sync");
 182                 return;
 183         }
 184
 185         g_topology_unlock();
 186         if (strcmp(verb, "add") == 0)
 187                 virstor_ctl_add(req, cp);
 188         else if (strcmp(verb, "stop") == 0 || strcmp(verb, "destroy") == 0)
 189                 virstor_ctl_stop(req, cp);
 190         else if (strcmp(verb, "remove") == 0)
 191                 virstor_ctl_remove(req, cp);
 192         else
 193                 gctl_error(req, "unknown verb: '%s'", verb);
 194         g_topology_lock();
 195 }
 196
 197 /*
 198  * "stop" verb from userland
 199  */
 200 static void
 201 virstor_ctl_stop(struct gctl_req *req, struct g_class *cp)
 202 {
 203         int *force, *nargs;
 204         int i;
 205
 206         nargs = gctl_get_paraml(req, "nargs", sizeof *nargs);
 207         if (nargs == NULL) {
 208                 gctl_error(req, "Error fetching argument '%s'", "nargs");
 209                 return;
 210         }
 211         if (*nargs < 1) {
 212                 gctl_error(req, "Invalid number of arguments");
 213                 return;
 214         }
 215         force = gctl_get_paraml(req, "force", sizeof *force);
 216         if (force == NULL) {
 217                 gctl_error(req, "Error fetching argument '%s'", "force");
 218                 return;
 219         }
 220
 221         g_topology_lock();
 222         for (i = 0; i < *nargs; i++) {
 223                 char param[8];
 224                 const char *name;
 225                 struct g_virstor_softc *sc;
 226                 int error;
 227
 228                 sprintf(param, "arg%d", i);
 229                 name = gctl_get_asciiparam(req, param);
 230                 if (name == NULL) {
 231                         gctl_error(req, "No 'arg%d' argument", i);
 232                         g_topology_unlock();
 233                         return;
 234                 }
 235                 sc = virstor_find_geom(cp, name);
 236                 if (sc == NULL) {
 237                         gctl_error(req, "Don't know anything about '%s'", name);
 238                         g_topology_unlock();
 239                         return;
 240                 }
 241
 242                 LOG_MSG(LVL_INFO, "Stopping %s by the userland command",
 243                     sc->geom->name);
 244                 update_metadata(sc);
 245                 if ((error = virstor_geom_destroy(sc, TRUE, TRUE)) != 0) {
 246                         LOG_MSG(LVL_ERROR, "Cannot destroy %s: %d",
 247                             sc->geom->name, error);
 248                 }
 249         }
 250         g_topology_unlock();
 251 }
 252
 253 /*
 254  * "add" verb from userland - add new component(s) to the structure.
 255  * This will be done all at once in here, without going through the
 256  * .taste function for new components.
 257  */
 258 static void
 259 virstor_ctl_add(struct gctl_req *req, struct g_class *cp)
 260 {
 261         /* Note: while this is going on, I/O is being done on
 262          * the g_up and g_down threads. The idea is to make changes
 263          * to softc members in a way that can atomically activate
 264          * them all at once. */
 265         struct g_virstor_softc *sc;
 266         int *hardcode, *nargs;
 267         const char *geom_name;  /* geom to add a component to */
 268         struct g_consumer *fcp;
 269         struct g_virstor_bio_q *bq;
 270         u_int added;
 271         int error;
 272         int i;
 273
 274         nargs = gctl_get_paraml(req, "nargs", sizeof(*nargs));
 275         if (nargs == NULL) {
 276                 gctl_error(req, "Error fetching argument '%s'", "nargs");
 277                 return;
 278         }
 279         if (*nargs < 2) {
 280                 gctl_error(req, "Invalid number of arguments");
 281                 return;
 282         }
 283         hardcode = gctl_get_paraml(req, "hardcode", sizeof(*hardcode));
 284         if (hardcode == NULL) {
 285                 gctl_error(req, "Error fetching argument '%s'", "hardcode");
 286                 return;
 287         }
 288
 289         /* Find "our" geom */
 290         geom_name = gctl_get_asciiparam(req, "arg0");
 291         if (geom_name == NULL) {
 292                 gctl_error(req, "Error fetching argument '%s'", "geom_name (arg0)");
 293                 return;
 294         }
 295         sc = virstor_find_geom(cp, geom_name);
 296         if (sc == NULL) {
 297                 gctl_error(req, "Don't know anything about '%s'", geom_name);
 298                 return;
 299         }
 300
 301         if (virstor_valid_components(sc) != sc->n_components) {
 302                 LOG_MSG(LVL_ERROR, "Cannot add components to incomplete "
 303                     "virstor %s", sc->geom->name);
 304                 gctl_error(req, "Virstor %s is incomplete", sc->geom->name);
 305                 return;
 306         }
 307
 308         fcp = sc->components[0].gcons;
 309         added = 0;
 310         g_topology_lock();
 311         for (i = 1; i < *nargs; i++) {
 312                 struct g_virstor_metadata md;
 313                 char aname[8];
 314                 const char *prov_name;
 315                 struct g_provider *pp;
 316                 struct g_consumer *cp;
 317                 u_int nc;
 318                 u_int j;
 319
 320                 snprintf(aname, sizeof aname, "arg%d", i);
 321                 prov_name = gctl_get_asciiparam(req, aname);
 322                 if (prov_name == NULL) {
 323                         gctl_error(req, "Error fetching argument '%s'", aname);
 324                         g_topology_unlock();
 325                         return;
 326                 }
 327                 if (strncmp(prov_name, _PATH_DEV, sizeof(_PATH_DEV) - 1) == 0)
 328                         prov_name += sizeof(_PATH_DEV) - 1;
 329
 330                 pp = g_provider_by_name(prov_name);
 331                 if (pp == NULL) {
 332                         /* This is the most common error so be verbose about it */
 333                         if (added != 0) {
 334                                 gctl_error(req, "Invalid provider: '%s' (added"
 335                                     " %u components)", prov_name, added);
 336                                 update_metadata(sc);
 337                         } else {
 338                                 gctl_error(req, "Invalid provider: '%s'",
 339                                     prov_name);
 340                         }
 341                         g_topology_unlock();
 342                         return;
 343                 }
 344                 cp = g_new_consumer(sc->geom);
 345                 if (cp == NULL) {
 346                         gctl_error(req, "Cannot create consumer");
 347                         g_topology_unlock();
 348                         return;
 349                 }
 350                 error = g_attach(cp, pp);
 351                 if (error != 0) {
 352                         gctl_error(req, "Cannot attach a consumer to %s",
 353                             pp->name);
 354                         g_destroy_consumer(cp);
 355                         g_topology_unlock();
 356                         return;
 357                 }
 358                 if (fcp->acr != 0 || fcp->acw != 0 || fcp->ace != 0) {
 359                         error = g_access(cp, fcp->acr, fcp->acw, fcp->ace);
 360                         if (error != 0) {
 361                                 gctl_error(req, "Access request failed for %s",
 362                                     pp->name);
 363                                 g_destroy_consumer(cp);
 364                                 g_topology_unlock();
 365                                 return;
 366                         }
 367                 }
 368                 if (fcp->provider->sectorsize != pp->sectorsize) {
 369                         gctl_error(req, "Sector size doesn't fit for %s",
 370                             pp->name);
 371                         g_destroy_consumer(cp);
 372                         g_topology_unlock();
 373                         return;
 374                 }
 375                 for (j = 0; j < sc->n_components; j++) {
 376                         if (strcmp(sc->components[j].gcons->provider->name,
 377                             pp->name) == 0) {
 378                                 gctl_error(req, "Component %s already in %s",
 379                                     pp->name, sc->geom->name);
 380                                 g_destroy_consumer(cp);
 381                                 g_topology_unlock();
 382                                 return;
 383                         }
 384                 }
 385                 sc->components = realloc(sc->components,
 386                     sizeof(*sc->components) * (sc->n_components + 1),
 387                     M_GVIRSTOR, M_WAITOK);
 388
 389                 nc = sc->n_components;
 390                 sc->components[nc].gcons = cp;
 391                 sc->components[nc].sc = sc;
 392                 sc->components[nc].index = nc;
 393                 sc->components[nc].chunk_count = cp->provider->mediasize /
 394                     sc->chunk_size;
 395                 sc->components[nc].chunk_next = 0;
 396                 sc->components[nc].chunk_reserved = 0;
 397
 398                 if (sc->components[nc].chunk_count < 4) {
 399                         gctl_error(req, "Provider too small: %s",
 400                             cp->provider->name);
 401                         g_destroy_consumer(cp);
 402                         g_topology_unlock();
 403                         return;
 404                 }
 405                 fill_metadata(sc, &md, nc, *hardcode);
 406                 write_metadata(cp, &md);
 407                 /* The new component becomes visible when n_components is
 408                  * incremented */
 409                 sc->n_components++;
 410                 added++;
 411
 412         }
 413         /* This call to update_metadata() is critical. In case there's a
 414          * power failure in the middle of it and some components are updated
 415          * while others are not, there will be trouble on next .taste() iff
 416          * a non-updated component is detected first */
 417         update_metadata(sc);
 418         g_topology_unlock();
 419         LOG_MSG(LVL_INFO, "Added %d component(s) to %s", added,
 420             sc->geom->name);
 421         /* Fire off BIOs previously queued because there wasn't any
 422          * physical space left. If the BIOs still can't be satisfied
 423          * they will again be added to the end of the queue (during
 424          * which the mutex will be recursed) */
 425         bq = malloc(sizeof(*bq), M_GVIRSTOR, M_WAITOK);
 426         bq->bio = NULL;
 427         mtx_lock(&sc->delayed_bio_q_mtx);
 428         /* First, insert a sentinel to the queue end, so we don't
 429          * end up in an infinite loop if there's still no free
 430          * space available. */
 431         STAILQ_INSERT_TAIL(&sc->delayed_bio_q, bq, linkage);
 432         while (!STAILQ_EMPTY(&sc->delayed_bio_q)) {
 433                 bq = STAILQ_FIRST(&sc->delayed_bio_q);
 434                 if (bq->bio != NULL) {
 435                         g_virstor_start(bq->bio);
 436                         STAILQ_REMOVE_HEAD(&sc->delayed_bio_q, linkage);
 437                         free(bq, M_GVIRSTOR);
 438                 } else {
 439                         STAILQ_REMOVE_HEAD(&sc->delayed_bio_q, linkage);
 440                         free(bq, M_GVIRSTOR);
 441                         break;
 442                 }
 443         }
 444         mtx_unlock(&sc->delayed_bio_q_mtx);
 445
 446 }
 447
 448 /*
 449  * Find a geom handled by the class
 450  */
 451 static struct g_virstor_softc *
 452 virstor_find_geom(const struct g_class *cp, const char *name)
 453 {
 454         struct g_geom *gp;
 455
 456         LIST_FOREACH(gp, &cp->geom, geom) {
 457                 if (strcmp(name, gp->name) == 0)
 458                         return (gp->softc);
 459         }
 460         return (NULL);
 461 }
 462
 463 /*
 464  * Update metadata on all components to reflect the current state
 465  * of these fields:
 466  *    - chunk_next
 467  *    - flags
 468  *    - md_count
 469  * Expects things to be set up so write_metadata() can work, i.e.
 470  * the topology lock must be held.
 471  */
 472 static void
 473 update_metadata(struct g_virstor_softc *sc)
 474 {
 475         struct g_virstor_metadata md;
 476         u_int n;
 477
 478         if (virstor_valid_components(sc) != sc->n_components)
 479                 return; /* Incomplete device */
 480         LOG_MSG(LVL_DEBUG, "Updating metadata on components for %s",
 481             sc->geom->name);
 482         /* Update metadata on components */
 483         g_trace(G_T_TOPOLOGY, "%s(%s, %s)", __func__,
 484             sc->geom->class->name, sc->geom->name);
 485         g_topology_assert();
 486         for (n = 0; n < sc->n_components; n++) {
 487                 read_metadata(sc->components[n].gcons, &md);
 488                 md.chunk_next = sc->components[n].chunk_next;
 489                 md.flags = sc->components[n].flags;
 490                 md.md_count = sc->n_components;
 491                 write_metadata(sc->components[n].gcons, &md);
 492         }
 493 }
 494
 495 /*
 496  * Fills metadata (struct md) from information stored in softc and the nc'th
 497  * component of virstor
 498  */
 499 static void
 500 fill_metadata(struct g_virstor_softc *sc, struct g_virstor_metadata *md,
 501     u_int nc, u_int hardcode)
 502 {
 503         struct g_virstor_component *c;
 504
 505         bzero(md, sizeof *md);
 506         c = &sc->components[nc];
 507
 508         strncpy(md->md_magic, G_VIRSTOR_MAGIC, sizeof md->md_magic);
 509         md->md_version = G_VIRSTOR_VERSION;
 510         strncpy(md->md_name, sc->geom->name, sizeof md->md_name);
 511         md->md_id = sc->id;
 512         md->md_virsize = sc->virsize;
 513         md->md_chunk_size = sc->chunk_size;
 514         md->md_count = sc->n_components;
 515
 516         if (hardcode) {
 517                 strncpy(md->provider, c->gcons->provider->name,
 518                     sizeof md->provider);
 519         }
 520         md->no = nc;
 521         md->provsize = c->gcons->provider->mediasize;
 522         md->chunk_count = c->chunk_count;
 523         md->chunk_next = c->chunk_next;
 524         md->chunk_reserved = c->chunk_reserved;
 525         md->flags = c->flags;
 526 }
 527
 528 /*
 529  * Remove a component from virstor device.
 530  * Can only be done if the component is unallocated.
 531  */
 532 static void
 533 virstor_ctl_remove(struct gctl_req *req, struct g_class *cp)
 534 {
 535         /* As this is executed in parallel to I/O, operations on virstor
 536          * structures must be as atomic as possible. */
 537         struct g_virstor_softc *sc;
 538         int *nargs;
 539         const char *geom_name;
 540         u_int removed;
 541         int i;
 542
 543         nargs = gctl_get_paraml(req, "nargs", sizeof(*nargs));
 544         if (nargs == NULL) {
 545                 gctl_error(req, "Error fetching argument '%s'", "nargs");
 546                 return;
 547         }
 548         if (*nargs < 2) {
 549                 gctl_error(req, "Invalid number of arguments");
 550                 return;
 551         }
 552         /* Find "our" geom */
 553         geom_name = gctl_get_asciiparam(req, "arg0");
 554         if (geom_name == NULL) {
 555                 gctl_error(req, "Error fetching argument '%s'",
 556                     "geom_name (arg0)");
 557                 return;
 558         }
 559         sc = virstor_find_geom(cp, geom_name);
 560         if (sc == NULL) {
 561                 gctl_error(req, "Don't know anything about '%s'", geom_name);
 562                 return;
 563         }
 564
 565         if (virstor_valid_components(sc) != sc->n_components) {
 566                 LOG_MSG(LVL_ERROR, "Cannot remove components from incomplete "
 567                     "virstor %s", sc->geom->name);
 568                 gctl_error(req, "Virstor %s is incomplete", sc->geom->name);
 569                 return;
 570         }
 571
 572         removed = 0;
 573         for (i = 1; i < *nargs; i++) {
 574                 char param[8];
 575                 const char *prov_name;
 576                 int j, found;
 577                 struct g_virstor_component *newcomp, *compbak;
 578
 579                 sprintf(param, "arg%d", i);
 580                 prov_name = gctl_get_asciiparam(req, param);
 581                 if (prov_name == NULL) {
 582                         gctl_error(req, "Error fetching argument '%s'", param);
 583                         return;
 584                 }
 585                 if (strncmp(prov_name, _PATH_DEV, sizeof(_PATH_DEV) - 1) == 0)
 586                         prov_name += sizeof(_PATH_DEV) - 1;
 587
 588                 found = -1;
 589                 for (j = 0; j < sc->n_components; j++) {
 590                         if (strcmp(sc->components[j].gcons->provider->name,
 591                             prov_name) == 0) {
 592                                 found = j;
 593                                 break;
 594                         }
 595                 }
 596                 if (found == -1) {
 597                         LOG_MSG(LVL_ERROR, "No %s component in %s",
 598                             prov_name, sc->geom->name);
 599                         continue;
 600                 }
 601
 602                 compbak = sc->components;
 603                 newcomp = malloc(sc->n_components * sizeof(*sc->components),
 604                     M_GVIRSTOR, M_WAITOK | M_ZERO);
 605                 bcopy(sc->components, newcomp, found * sizeof(*sc->components));
 606                 bcopy(&sc->components[found + 1], newcomp + found,
 607                     found * sizeof(*sc->components));
 608                 if ((sc->components[j].flags & VIRSTOR_PROVIDER_ALLOCATED) != 0) {
 609                         LOG_MSG(LVL_ERROR, "Allocated provider %s cannot be "
 610                             "removed from %s",
 611                             prov_name, sc->geom->name);
 612                         free(newcomp, M_GVIRSTOR);
 613                         /* We'll consider this non-fatal error */
 614                         continue;
 615                 }
 616                 /* Renumerate unallocated components */
 617                 for (j = 0; j < sc->n_components-1; j++) {
 618                         if ((sc->components[j].flags &
 619                             VIRSTOR_PROVIDER_ALLOCATED) == 0) {
 620                                 sc->components[j].index = j;
 621                         }
 622                 }
 623                 /* This is the critical section. If a component allocation
 624                  * event happens while both variables are not yet set,
 625                  * there will be trouble. Something will panic on encountering
 626                  * NULL sc->components[x].gcomp member.
 627                  * Luckily, component allocation happens very rarely and
 628                  * removing components is an abnormal action in any case. */
 629                 sc->components = newcomp;
 630                 sc->n_components--;
 631                 /* End critical section */
 632
 633                 g_topology_lock();
 634                 if (clear_metadata(&compbak[found]) != 0) {
 635                         LOG_MSG(LVL_WARNING, "Trouble ahead: cannot clear "
 636                             "metadata on %s", prov_name);
 637                 }
 638                 g_detach(compbak[found].gcons);
 639                 g_destroy_consumer(compbak[found].gcons);
 640                 g_topology_unlock();
 641
 642                 free(compbak, M_GVIRSTOR);
 643
 644                 removed++;
 645         }
 646
 647         /* This call to update_metadata() is critical. In case there's a
 648          * power failure in the middle of it and some components are updated
 649          * while others are not, there will be trouble on next .taste() iff
 650          * a non-updated component is detected first */
 651         g_topology_lock();
 652         update_metadata(sc);
 653         g_topology_unlock();
 654         LOG_MSG(LVL_INFO, "Removed %d component(s) from %s", removed,
 655             sc->geom->name);
 656 }
 657
 658 /*
 659  * Clear metadata sector on component
 660  */
 661 static int
 662 clear_metadata(struct g_virstor_component *comp)
 663 {
 664         char *buf;
 665         int error;
 666
 667         LOG_MSG(LVL_INFO, "Clearing metadata on %s",
 668             comp->gcons->provider->name);
 669         g_topology_assert();
 670         error = g_access(comp->gcons, 0, 1, 0);
 671         if (error != 0)
 672                 return (error);
 673         buf = malloc(comp->gcons->provider->sectorsize, M_GVIRSTOR,
 674             M_WAITOK | M_ZERO);
 675         error = g_write_data(comp->gcons,
 676             comp->gcons->provider->mediasize -
 677             comp->gcons->provider->sectorsize,
 678             buf,
 679             comp->gcons->provider->sectorsize);
 680         free(buf, M_GVIRSTOR);
 681         g_access(comp->gcons, 0, -1, 0);
 682         return (error);
 683 }
 684
 685 /*
 686  * Destroy geom forcibly.
 687  */
 688 static int
 689 g_virstor_destroy_geom(struct gctl_req *req __unused, struct g_class *mp,
 690     struct g_geom *gp)
 691 {
 692         struct g_virstor_softc *sc;
 693         int exitval;
 694
 695         sc = gp->softc;
 696         KASSERT(sc != NULL, ("%s: NULL sc", __func__));
 697
 698         exitval = 0;
 699         LOG_MSG(LVL_DEBUG, "%s called for %s, sc=%p", __func__, gp->name,
 700             gp->softc);
 701
 702         if (sc != NULL) {
 703 #ifdef INVARIANTS
 704                 char *buf;
 705                 int error;
 706                 off_t off;
 707                 int isclean, count;
 708                 int n;
 709
 710                 LOG_MSG(LVL_INFO, "INVARIANTS detected");
 711                 LOG_MSG(LVL_INFO, "Verifying allocation "
 712                     "table for %s", sc->geom->name);
 713                 count = 0;
 714                 for (n = 0; n < sc->chunk_count; n++) {
 715                         if (sc->map[n].flags || VIRSTOR_MAP_ALLOCATED != 0)
 716                                 count++;
 717                 }
 718                 LOG_MSG(LVL_INFO, "Device %s has %d allocated chunks",
 719                     sc->geom->name, count);
 720                 n = off = count = 0;
 721                 isclean = 1;
 722                 if (virstor_valid_components(sc) != sc->n_components) {
 723                         /* This is a incomplete virstor device (not all
 724                          * components have been found) */
 725                         LOG_MSG(LVL_ERROR, "Device %s is incomplete",
 726                             sc->geom->name);
 727                         goto bailout;
 728                 }
 729                 error = g_access(sc->components[0].gcons, 1, 0, 0);
 730                 KASSERT(error == 0, ("%s: g_access failed (%d)", __func__,
 731                     error));
 732                 /* Compare the whole on-disk allocation table with what's
 733                  * currently in memory */
 734                 while (n < sc->chunk_count) {
 735                         buf = g_read_data(sc->components[0].gcons, off,
 736                             sc->sectorsize, &error);
 737                         KASSERT(buf != NULL, ("g_read_data returned NULL (%d) "
 738                             "for read at %jd", error, off));
 739                         if (bcmp(buf, &sc->map[n], sc->sectorsize) != 0) {
 740                                 LOG_MSG(LVL_ERROR, "ERROR in allocation table, "
 741                                     "entry %d, offset %jd", n, off);
 742                                 isclean = 0;
 743                                 count++;
 744                         }
 745                         n += sc->me_per_sector;
 746                         off += sc->sectorsize;
 747                         g_free(buf);
 748                 }
 749                 error = g_access(sc->components[0].gcons, -1, 0, 0);
 750                 KASSERT(error == 0, ("%s: g_access failed (%d) on exit",
 751                     __func__, error));
 752                 if (isclean != 1) {
 753                         LOG_MSG(LVL_ERROR, "ALLOCATION TABLE CORRUPTED FOR %s "
 754                             "(%d sectors don't match, max %zu allocations)",
 755                             sc->geom->name, count,
 756                             count * sc->me_per_sector);
 757                 } else {
 758                         LOG_MSG(LVL_INFO, "Allocation table ok for %s",
 759                             sc->geom->name);
 760                 }
 761 bailout:
 762 #endif
 763                 update_metadata(sc);
 764                 virstor_geom_destroy(sc, FALSE, FALSE);
 765                 exitval = EAGAIN;
 766         } else
 767                 exitval = 0;
 768         return (exitval);
 769 }
 770
 771 /*
 772  * Taste event (per-class callback)
 773  * Examines a provider and creates geom instances if needed
 774  */
 775 static struct g_geom *
 776 g_virstor_taste(struct g_class *mp, struct g_provider *pp, int flags)
 777 {
 778         struct g_virstor_metadata md;
 779         struct g_geom *gp;
 780         struct g_consumer *cp;
 781         struct g_virstor_softc *sc;
 782         int error;
 783
 784         g_trace(G_T_TOPOLOGY, "%s(%s, %s)", __func__, mp->name, pp->name);
 785         g_topology_assert();
 786         LOG_MSG(LVL_DEBUG, "Tasting %s", pp->name);
 787
 788         /* We need a dummy geom to attach a consumer to the given provider */
 789         gp = g_new_geomf(mp, "virstor:taste.helper");
 790         gp->start = (void *)invalid_call;       /* XXX: hacked up so the        */
 791         gp->access = (void *)invalid_call;      /* compiler doesn't complain.   */
 792         gp->orphan = (void *)invalid_call;      /* I really want these to fail. */
 793
 794         cp = g_new_consumer(gp);
 795         g_attach(cp, pp);
 796         error = read_metadata(cp, &md);
 797         g_detach(cp);
 798         g_destroy_consumer(cp);
 799         g_destroy_geom(gp);
 800
 801         if (error != 0)
 802                 return (NULL);
 803
 804         if (strcmp(md.md_magic, G_VIRSTOR_MAGIC) != 0)
 805                 return (NULL);
 806         if (md.md_version != G_VIRSTOR_VERSION) {
 807                 LOG_MSG(LVL_ERROR, "Kernel module version invalid "
 808                     "to handle %s (%s) : %d should be %d",
 809                     md.md_name, pp->name, md.md_version, G_VIRSTOR_VERSION);
 810                 return (NULL);
 811         }
 812         if (md.provsize != pp->mediasize)
 813                 return (NULL);
 814
 815         /* If the provider name is hardcoded, use the offered provider only
 816          * if it's been offered with its proper name (the one used in
 817          * the label command). */
 818         if (md.provider[0] != '\0' &&
 819             !g_compare_names(md.provider, pp->name))
 820                 return (NULL);
 821
 822         /* Iterate all geoms this class already knows about to see if a new
 823          * geom instance of this class needs to be created (in case the provider
 824          * is first from a (possibly) multi-consumer geom) or it just needs
 825          * to be added to an existing instance. */
 826         sc = NULL;
 827         gp = NULL;
 828         LIST_FOREACH(gp, &mp->geom, geom) {
 829                 sc = gp->softc;
 830                 if (sc == NULL)
 831                         continue;
 832                 if (strcmp(md.md_name, sc->geom->name) != 0)
 833                         continue;
 834                 if (md.md_id != sc->id)
 835                         continue;
 836                 break;
 837         }
 838         if (gp != NULL) { /* We found an existing geom instance; add to it */
 839                 LOG_MSG(LVL_INFO, "Adding %s to %s", pp->name, md.md_name);
 840                 error = add_provider_to_geom(sc, pp, &md);
 841                 if (error != 0) {
 842                         LOG_MSG(LVL_ERROR, "Error adding %s to %s (error %d)",
 843                             pp->name, md.md_name, error);
 844                         return (NULL);
 845                 }
 846         } else { /* New geom instance needs to be created */
 847                 gp = create_virstor_geom(mp, &md);
 848                 if (gp == NULL) {
 849                         LOG_MSG(LVL_ERROR, "Error creating new instance of "
 850                             "class %s: %s", mp->name, md.md_name);
 851                         LOG_MSG(LVL_DEBUG, "Error creating %s at %s",
 852                             md.md_name, pp->name);
 853                         return (NULL);
 854                 }
 855                 sc = gp->softc;
 856                 LOG_MSG(LVL_INFO, "Adding %s to %s (first found)", pp->name,
 857                     md.md_name);
 858                 error = add_provider_to_geom(sc, pp, &md);
 859                 if (error != 0) {
 860                         LOG_MSG(LVL_ERROR, "Error adding %s to %s (error %d)",
 861                             pp->name, md.md_name, error);
 862                         virstor_geom_destroy(sc, TRUE, FALSE);
 863                         return (NULL);
 864                 }
 865         }
 866
 867         return (gp);
 868 }
 869
 870 /*
 871  * Destroyes consumer passed to it in arguments. Used as a callback
 872  * on g_event queue.
 873  */
 874 static void
 875 delay_destroy_consumer(void *arg, int flags __unused)
 876 {
 877         struct g_consumer *c = arg;
 878         KASSERT(c != NULL, ("%s: invalid consumer", __func__));
 879         LOG_MSG(LVL_DEBUG, "Consumer %s destroyed with delay",
 880             c->provider->name);
 881         g_detach(c);
 882         g_destroy_consumer(c);
 883 }
 884
 885 /*
 886  * Remove a component (consumer) from geom instance; If it's the first
 887  * component being removed, orphan the provider to announce geom's being
 888  * dismantled
 889  */
 890 static void
 891 remove_component(struct g_virstor_softc *sc, struct g_virstor_component *comp,
 892     boolean_t delay)
 893 {
 894         struct g_consumer *c;
 895
 896         KASSERT(comp->gcons != NULL, ("Component with no consumer in %s",
 897             sc->geom->name));
 898         c = comp->gcons;
 899
 900         comp->gcons = NULL;
 901         KASSERT(c->provider != NULL, ("%s: no provider", __func__));
 902         LOG_MSG(LVL_DEBUG, "Component %s removed from %s", c->provider->name,
 903             sc->geom->name);
 904         if (sc->provider != NULL) {
 905                 LOG_MSG(LVL_INFO, "Removing provider %s", sc->provider->name);
 906                 g_wither_provider(sc->provider, ENXIO);
 907                 sc->provider = NULL;
 908         }
 909
 910         if (c->acr > 0 || c->acw > 0 || c->ace > 0)
 911                 g_access(c, -c->acr, -c->acw, -c->ace);
 912         if (delay) {
 913                 /* Destroy consumer after it's tasted */
 914                 g_post_event(delay_destroy_consumer, c, M_WAITOK, NULL);
 915         } else {
 916                 g_detach(c);
 917                 g_destroy_consumer(c);
 918         }
 919 }
 920
 921 /*
 922  * Destroy geom - called internally
 923  * See g_virstor_destroy_geom for the other one
 924  */
 925 static int
 926 virstor_geom_destroy(struct g_virstor_softc *sc, boolean_t force,
 927     boolean_t delay)
 928 {
 929         struct g_provider *pp;
 930         struct g_geom *gp;
 931         u_int n;
 932
 933         g_topology_assert();
 934
 935         if (sc == NULL)
 936                 return (ENXIO);
 937
 938         pp = sc->provider;
 939         if (pp != NULL && (pp->acr != 0 || pp->acw != 0 || pp->ace != 0)) {
 940                 LOG_MSG(force ? LVL_WARNING : LVL_ERROR,
 941                     "Device %s is still open.", pp->name);
 942                 if (!force)
 943                         return (EBUSY);
 944         }
 945
 946         for (n = 0; n < sc->n_components; n++) {
 947                 if (sc->components[n].gcons != NULL)
 948                         remove_component(sc, &sc->components[n], delay);
 949         }
 950
 951         gp = sc->geom;
 952         gp->softc = NULL;
 953
 954         KASSERT(sc->provider == NULL, ("Provider still exists for %s",
 955             gp->name));
 956
 957         /* XXX: This might or might not work, since we're called with
 958          * the topology lock held. Also, it might panic the kernel if
 959          * the error'd BIO is in softupdates code. */
 960         mtx_lock(&sc->delayed_bio_q_mtx);
 961         while (!STAILQ_EMPTY(&sc->delayed_bio_q)) {
 962                 struct g_virstor_bio_q *bq;
 963                 bq = STAILQ_FIRST(&sc->delayed_bio_q);
 964                 bq->bio->bio_error = ENOSPC;
 965                 g_io_deliver(bq->bio, EIO);
 966                 STAILQ_REMOVE_HEAD(&sc->delayed_bio_q, linkage);
 967                 free(bq, M_GVIRSTOR);
 968         }
 969         mtx_unlock(&sc->delayed_bio_q_mtx);
 970         mtx_destroy(&sc->delayed_bio_q_mtx);
 971
 972         free(sc->map, M_GVIRSTOR);
 973         free(sc->components, M_GVIRSTOR);
 974         bzero(sc, sizeof *sc);
 975         free(sc, M_GVIRSTOR);
 976
 977         pp = LIST_FIRST(&gp->provider); /* We only offer one provider */
 978         if (pp == NULL || (pp->acr == 0 && pp->acw == 0 && pp->ace == 0))
 979                 LOG_MSG(LVL_DEBUG, "Device %s destroyed", gp->name);
 980
 981         g_wither_geom(gp, ENXIO);
 982
 983         return (0);
 984 }
 985
 986 /*
 987  * Utility function: read metadata & decode. Wants topology lock to be
 988  * held.
 989  */
 990 static int
 991 read_metadata(struct g_consumer *cp, struct g_virstor_metadata *md)
 992 {
 993         struct g_provider *pp;
 994         char *buf;
 995         int error;
 996
 997         g_topology_assert();
 998         error = g_access(cp, 1, 0, 0);
 999         if (error != 0)
1000                 return (error);
1001         pp = cp->provider;
1002         g_topology_unlock();
1003         buf = g_read_data(cp, pp->mediasize - pp->sectorsize, pp->sectorsize,
1004             &error);
1005         g_topology_lock();
1006         g_access(cp, -1, 0, 0);
1007         if (buf == NULL)
1008                 return (error);
1009
1010         virstor_metadata_decode(buf, md);
1011         g_free(buf);
1012
1013         return (0);
1014 }
1015
1016 /**
1017  * Utility function: encode & write metadata. Assumes topology lock is
1018  * held.
1019  *
1020  * There is no useful way of recovering from errors in this function,
1021  * not involving panicking the kernel. If the metadata cannot be written
1022  * the most we can do is notify the operator and hope he spots it and
1023  * replaces the broken drive.
1024  */
1025 static void
1026 write_metadata(struct g_consumer *cp, struct g_virstor_metadata *md)
1027 {
1028         struct g_provider *pp;
1029         char *buf;
1030         int error;
1031
1032         KASSERT(cp != NULL && md != NULL && cp->provider != NULL,
1033             ("Something's fishy in %s", __func__));
1034         LOG_MSG(LVL_DEBUG, "Writing metadata on %s", cp->provider->name);
1035         g_topology_assert();
1036         error = g_access(cp, 0, 1, 0);
1037         if (error != 0) {
1038                 LOG_MSG(LVL_ERROR, "g_access(0,1,0) failed for %s: %d",
1039                     cp->provider->name, error);
1040                 return;
1041         }
1042         pp = cp->provider;
1043
1044         buf = malloc(pp->sectorsize, M_GVIRSTOR, M_WAITOK);
1045         bzero(buf, pp->sectorsize);
1046         virstor_metadata_encode(md, buf);
1047         g_topology_unlock();
1048         error = g_write_data(cp, pp->mediasize - pp->sectorsize, buf,
1049             pp->sectorsize);
1050         g_topology_lock();
1051         g_access(cp, 0, -1, 0);
1052         free(buf, M_GVIRSTOR);
1053
1054         if (error != 0)
1055                 LOG_MSG(LVL_ERROR, "Error %d writing metadata to %s",
1056                     error, cp->provider->name);
1057 }
1058
1059 /*
1060  * Creates a new instance of this GEOM class, initialise softc
1061  */
1062 static struct g_geom *
1063 create_virstor_geom(struct g_class *mp, struct g_virstor_metadata *md)
1064 {
1065         struct g_geom *gp;
1066         struct g_virstor_softc *sc;
1067
1068         LOG_MSG(LVL_DEBUG, "Creating geom instance for %s (id=%u)",
1069             md->md_name, md->md_id);
1070
1071         if (md->md_count < 1 || md->md_chunk_size < 1 ||
1072             md->md_virsize < md->md_chunk_size) {
1073                 /* This is bogus configuration, and probably means data is
1074                  * somehow corrupted. Panic, maybe? */
1075                 LOG_MSG(LVL_ERROR, "Nonsensical metadata information for %s",
1076                     md->md_name);
1077                 return (NULL);
1078         }
1079
1080         /* Check if it's already created */
1081         LIST_FOREACH(gp, &mp->geom, geom) {
1082                 sc = gp->softc;
1083                 if (sc != NULL && strcmp(sc->geom->name, md->md_name) == 0) {
1084                         LOG_MSG(LVL_WARNING, "Geom %s already exists",
1085                             md->md_name);
1086                         if (sc->id != md->md_id) {
1087                                 LOG_MSG(LVL_ERROR,
1088                                     "Some stale or invalid components "
1089                                     "exist for virstor device named %s. "
1090                                     "You will need to <CLEAR> all stale "
1091                                     "components and maybe reconfigure "
1092                                     "the virstor device. Tune "
1093                                     "kern.geom.virstor.debug sysctl up "
1094                                     "for more information.",
1095                                     sc->geom->name);
1096                         }
1097                         return (NULL);
1098                 }
1099         }
1100         gp = g_new_geomf(mp, "%s", md->md_name);
1101         gp->softc = NULL; /* to circumevent races that test softc */
1102
1103         gp->start = g_virstor_start;
1104         gp->spoiled = g_virstor_orphan;
1105         gp->orphan = g_virstor_orphan;
1106         gp->access = g_virstor_access;
1107         gp->dumpconf = g_virstor_dumpconf;
1108
1109         sc = malloc(sizeof(*sc), M_GVIRSTOR, M_WAITOK | M_ZERO);
1110         sc->id = md->md_id;
1111         sc->n_components = md->md_count;
1112         sc->components = malloc(sizeof(struct g_virstor_component) * md->md_count,
1113             M_GVIRSTOR, M_WAITOK | M_ZERO);
1114         sc->chunk_size = md->md_chunk_size;
1115         sc->virsize = md->md_virsize;
1116         STAILQ_INIT(&sc->delayed_bio_q);
1117         mtx_init(&sc->delayed_bio_q_mtx, "gvirstor_delayed_bio_q_mtx",
1118             "gvirstor", MTX_DEF | MTX_RECURSE);
1119
1120         sc->geom = gp;
1121         sc->provider = NULL; /* virstor_check_and_run will create it */
1122         gp->softc = sc;
1123
1124         LOG_MSG(LVL_ANNOUNCE, "Device %s created", sc->geom->name);
1125
1126         return (gp);
1127 }
1128
1129 /*
1130  * Add provider to a GEOM class instance
1131  */
1132 static int
1133 add_provider_to_geom(struct g_virstor_softc *sc, struct g_provider *pp,
1134     struct g_virstor_metadata *md)
1135 {
1136         struct g_virstor_component *component;
1137         struct g_consumer *cp, *fcp;
1138         struct g_geom *gp;
1139         int error;
1140
1141         if (md->no >= sc->n_components)
1142                 return (EINVAL);
1143
1144         /* "Current" compontent */
1145         component = &(sc->components[md->no]);
1146         if (component->gcons != NULL)
1147                 return (EEXIST);
1148
1149         gp = sc->geom;
1150         fcp = LIST_FIRST(&gp->consumer);
1151
1152         cp = g_new_consumer(gp);
1153         error = g_attach(cp, pp);
1154
1155         if (error != 0) {
1156                 g_destroy_consumer(cp);
1157                 return (error);
1158         }
1159
1160         if (fcp != NULL) {
1161                 if (fcp->provider->sectorsize != pp->sectorsize) {
1162                         /* TODO: this can be made to work */
1163                         LOG_MSG(LVL_ERROR, "Provider %s of %s has invalid "
1164                             "sector size (%d)", pp->name, sc->geom->name,
1165                             pp->sectorsize);
1166                         return (EINVAL);
1167                 }
1168                 if (fcp->acr > 0 || fcp->acw || fcp->ace > 0) {
1169                         /* Replicate access permissions from first "live" consumer
1170                          * to the new one */
1171                         error = g_access(cp, fcp->acr, fcp->acw, fcp->ace);
1172                         if (error != 0) {
1173                                 g_detach(cp);
1174                                 g_destroy_consumer(cp);
1175                                 return (error);
1176                         }
1177                 }
1178         }
1179
1180         /* Bring up a new component */
1181         cp->private = component;
1182         component->gcons = cp;
1183         component->sc = sc;
1184         component->index = md->no;
1185         component->chunk_count = md->chunk_count;
1186         component->chunk_next = md->chunk_next;
1187         component->chunk_reserved = md->chunk_reserved;
1188         component->flags = md->flags;
1189
1190         LOG_MSG(LVL_DEBUG, "%s attached to %s", pp->name, sc->geom->name);
1191
1192         virstor_check_and_run(sc);
1193         return (0);
1194 }
1195
1196 /*
1197  * Check if everything's ready to create the geom provider & device entry,
1198  * create and start provider.
1199  * Called ultimately by .taste, from g_event thread
1200  */
1201 static void
1202 virstor_check_and_run(struct g_virstor_softc *sc)
1203 {
1204         off_t off;
1205         size_t n, count;
1206         int index;
1207         int error;
1208
1209         if (virstor_valid_components(sc) != sc->n_components)
1210                 return;
1211
1212         if (virstor_valid_components(sc) == 0) {
1213                 /* This is actually a candidate for panic() */
1214                 LOG_MSG(LVL_ERROR, "No valid components for %s?",
1215                     sc->provider->name);
1216                 return;
1217         }
1218
1219         sc->sectorsize = sc->components[0].gcons->provider->sectorsize;
1220
1221         /* Initialise allocation map from the first consumer */
1222         sc->chunk_count = sc->virsize / sc->chunk_size;
1223         if (sc->chunk_count * (off_t)sc->chunk_size != sc->virsize) {
1224                 LOG_MSG(LVL_WARNING, "Device %s truncated to %ju bytes",
1225                     sc->provider->name,
1226                     sc->chunk_count * (off_t)sc->chunk_size);
1227         }
1228         sc->map_size = sc->chunk_count * sizeof *(sc->map);
1229         /* The following allocation is in order of 4MB - 8MB */
1230         sc->map = malloc(sc->map_size, M_GVIRSTOR, M_WAITOK);
1231         KASSERT(sc->map != NULL, ("%s: Memory allocation error (%zu bytes) for %s",
1232             __func__, sc->map_size, sc->provider->name));
1233         sc->map_sectors = sc->map_size / sc->sectorsize;
1234
1235         count = 0;
1236         for (n = 0; n < sc->n_components; n++)
1237                 count += sc->components[n].chunk_count;
1238         LOG_MSG(LVL_INFO, "Device %s has %zu physical chunks and %zu virtual "
1239             "(%zu KB chunks)",
1240             sc->geom->name, count, sc->chunk_count, sc->chunk_size / 1024);
1241
1242         error = g_access(sc->components[0].gcons, 1, 0, 0);
1243         if (error != 0) {
1244                 LOG_MSG(LVL_ERROR, "Cannot acquire read access for %s to "
1245                     "read allocation map for %s",
1246                     sc->components[0].gcons->provider->name,
1247                     sc->geom->name);
1248                 return;
1249         }
1250         /* Read in the allocation map */
1251         LOG_MSG(LVL_DEBUG, "Reading map for %s from %s", sc->geom->name,
1252             sc->components[0].gcons->provider->name);
1253         off = count = n = 0;
1254         while (count < sc->map_size) {
1255                 struct g_virstor_map_entry *mapbuf;
1256                 size_t bs;
1257
1258                 bs = MIN(MAXPHYS, sc->map_size - count);
1259                 if (bs % sc->sectorsize != 0) {
1260                         /* Check for alignment errors */
1261                         bs = rounddown(bs, sc->sectorsize);
1262                         if (bs == 0)
1263                                 break;
1264                         LOG_MSG(LVL_ERROR, "Trouble: map is not sector-aligned "
1265                             "for %s on %s", sc->geom->name,
1266                             sc->components[0].gcons->provider->name);
1267                 }
1268                 mapbuf = g_read_data(sc->components[0].gcons, off, bs, &error);
1269                 if (mapbuf == NULL) {
1270                         free(sc->map, M_GVIRSTOR);
1271                         LOG_MSG(LVL_ERROR, "Error reading allocation map "
1272                             "for %s from %s (offset %ju) (error %d)",
1273                             sc->geom->name,
1274                             sc->components[0].gcons->provider->name,
1275                             off, error);
1276                         return;
1277                 }
1278
1279                 bcopy(mapbuf, &sc->map[n], bs);
1280                 off += bs;
1281                 count += bs;
1282                 n += bs / sizeof *(sc->map);
1283                 g_free(mapbuf);
1284         }
1285         g_access(sc->components[0].gcons, -1, 0, 0);
1286         LOG_MSG(LVL_DEBUG, "Read map for %s", sc->geom->name);
1287
1288         /* find first component with allocatable chunks */
1289         index = -1;
1290         for (n = 0; n < sc->n_components; n++) {
1291                 if (sc->components[n].chunk_next <
1292                     sc->components[n].chunk_count) {
1293                         index = n;
1294                         break;
1295                 }
1296         }
1297         if (index == -1)
1298                 /* not found? set it to the last component and handle it
1299                  * later */
1300                 index = sc->n_components - 1;
1301
1302         if (index >= sc->n_components - g_virstor_component_watermark - 1) {
1303                 LOG_MSG(LVL_WARNING, "Device %s running out of components "
1304                     "(%d/%u: %s)", sc->geom->name,
1305                     index+1,
1306                     sc->n_components,
1307                     sc->components[index].gcons->provider->name);
1308         }
1309         sc->curr_component = index;
1310
1311         if (sc->components[index].chunk_next >=
1312             sc->components[index].chunk_count - g_virstor_chunk_watermark) {
1313                 LOG_MSG(LVL_WARNING,
1314                     "Component %s of %s is running out of free space "
1315                     "(%u chunks left)",
1316                     sc->components[index].gcons->provider->name,
1317                     sc->geom->name, sc->components[index].chunk_count -
1318                     sc->components[index].chunk_next);
1319         }
1320
1321         sc->me_per_sector = sc->sectorsize / sizeof *(sc->map);
1322         if (sc->sectorsize % sizeof *(sc->map) != 0) {
1323                 LOG_MSG(LVL_ERROR,
1324                     "%s: Map entries don't fit exactly in a sector (%s)",
1325                     __func__, sc->geom->name);
1326                 return;
1327         }
1328
1329         /* Recalculate allocated chunks in components & at the same time
1330          * verify map data is sane. We could trust metadata on this, but
1331          * we want to make sure. */
1332         for (n = 0; n < sc->n_components; n++)
1333                 sc->components[n].chunk_next = sc->components[n].chunk_reserved;
1334
1335         for (n = 0; n < sc->chunk_count; n++) {
1336                 if (sc->map[n].provider_no >= sc->n_components ||
1337                         sc->map[n].provider_chunk >=
1338                         sc->components[sc->map[n].provider_no].chunk_count) {
1339                         LOG_MSG(LVL_ERROR, "%s: Invalid entry %u in map for %s",
1340                             __func__, (u_int)n, sc->geom->name);
1341                         LOG_MSG(LVL_ERROR, "%s: provider_no: %u, n_components: %u"
1342                             " provider_chunk: %u, chunk_count: %u", __func__,
1343                             sc->map[n].provider_no, sc->n_components,
1344                             sc->map[n].provider_chunk,
1345                             sc->components[sc->map[n].provider_no].chunk_count);
1346                         return;
1347                 }
1348                 if (sc->map[n].flags & VIRSTOR_MAP_ALLOCATED)
1349                         sc->components[sc->map[n].provider_no].chunk_next++;
1350         }
1351
1352         sc->provider = g_new_providerf(sc->geom, "virstor/%s",
1353             sc->geom->name);
1354
1355         sc->provider->sectorsize = sc->sectorsize;
1356         sc->provider->mediasize = sc->virsize;
1357         g_error_provider(sc->provider, 0);
1358
1359         LOG_MSG(LVL_INFO, "%s activated", sc->provider->name);
1360         LOG_MSG(LVL_DEBUG, "%s starting with current component %u, starting "
1361             "chunk %u", sc->provider->name, sc->curr_component,
1362             sc->components[sc->curr_component].chunk_next);
1363 }
1364
1365 /*
1366  * Returns count of active providers in this geom instance
1367  */
1368 static u_int
1369 virstor_valid_components(struct g_virstor_softc *sc)
1370 {
1371         unsigned int nc, i;
1372
1373         nc = 0;
1374         KASSERT(sc != NULL, ("%s: softc is NULL", __func__));
1375         KASSERT(sc->components != NULL, ("%s: sc->components is NULL", __func__));
1376         for (i = 0; i < sc->n_components; i++)
1377                 if (sc->components[i].gcons != NULL)
1378                         nc++;
1379         return (nc);
1380 }
1381
1382 /*
1383  * Called when the consumer gets orphaned (?)
1384  */
1385 static void
1386 g_virstor_orphan(struct g_consumer *cp)
1387 {
1388         struct g_virstor_softc *sc;
1389         struct g_virstor_component *comp;
1390         struct g_geom *gp;
1391
1392         g_topology_assert();
1393         gp = cp->geom;
1394         sc = gp->softc;
1395         if (sc == NULL)
1396                 return;
1397
1398         comp = cp->private;
1399         KASSERT(comp != NULL, ("%s: No component in private part of consumer",
1400             __func__));
1401         remove_component(sc, comp, FALSE);
1402         if (virstor_valid_components(sc) == 0)
1403                 virstor_geom_destroy(sc, TRUE, FALSE);
1404 }
1405
1406 /*
1407  * Called to notify geom when it's been opened, and for what intent
1408  */
1409 static int
1410 g_virstor_access(struct g_provider *pp, int dr, int dw, int de)
1411 {
1412         struct g_consumer *c;
1413         struct g_virstor_softc *sc;
1414         struct g_geom *gp;
1415         int error;
1416
1417         KASSERT(pp != NULL, ("%s: NULL provider", __func__));
1418         gp = pp->geom;
1419         KASSERT(gp != NULL, ("%s: NULL geom", __func__));
1420         sc = gp->softc;
1421
1422         if (sc == NULL) {
1423                 /* It seems that .access can be called with negative dr,dw,dx
1424                  * in this case but I want to check for myself */
1425                 LOG_MSG(LVL_WARNING, "access(%d, %d, %d) for %s",
1426                     dr, dw, de, pp->name);
1427                 /* This should only happen when geom is withered so
1428                  * allow only negative requests */
1429                 KASSERT(dr <= 0 && dw <= 0 && de <= 0,
1430                     ("%s: Positive access for %s", __func__, pp->name));
1431                 if (pp->acr + dr == 0 && pp->acw + dw == 0 && pp->ace + de == 0)
1432                         LOG_MSG(LVL_DEBUG, "Device %s definitely destroyed",
1433                             pp->name);
1434                 return (0);
1435         }
1436
1437         /* Grab an exclusive bit to propagate on our consumers on first open */
1438         if (pp->acr == 0 && pp->acw == 0 && pp->ace == 0)
1439                 de++;
1440         /* ... drop it on close */
1441         if (pp->acr + dr == 0 && pp->acw + dw == 0 && pp->ace + de == 0) {
1442                 de--;
1443                 update_metadata(sc);    /* Writes statistical information */
1444         }
1445
1446         error = ENXIO;
1447         LIST_FOREACH(c, &gp->consumer, consumer) {
1448                 KASSERT(c != NULL, ("%s: consumer is NULL", __func__));
1449                 error = g_access(c, dr, dw, de);
1450                 if (error != 0) {
1451                         struct g_consumer *c2;
1452
1453                         /* Backout earlier changes */
1454                         LIST_FOREACH(c2, &gp->consumer, consumer) {
1455                                 if (c2 == c) /* all eariler components fixed */
1456                                         return (error);
1457                                 g_access(c2, -dr, -dw, -de);
1458                         }
1459                 }
1460         }
1461
1462         return (error);
1463 }
1464
1465 /*
1466  * Generate XML dump of current state
1467  */
1468 static void
1469 g_virstor_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp,
1470     struct g_consumer *cp, struct g_provider *pp)
1471 {
1472         struct g_virstor_softc *sc;
1473
1474         g_topology_assert();
1475         sc = gp->softc;
1476
1477         if (sc == NULL || pp != NULL)
1478                 return;
1479
1480         if (cp != NULL) {
1481                 /* For each component */
1482                 struct g_virstor_component *comp;
1483
1484                 comp = cp->private;
1485                 if (comp == NULL)
1486                         return;
1487                 sbuf_printf(sb, "%s<ComponentIndex>%u</ComponentIndex>\n",
1488                     indent, comp->index);
1489                 sbuf_printf(sb, "%s<ChunkCount>%u</ChunkCount>\n",
1490                     indent, comp->chunk_count);
1491                 sbuf_printf(sb, "%s<ChunksUsed>%u</ChunksUsed>\n",
1492                     indent, comp->chunk_next);
1493                 sbuf_printf(sb, "%s<ChunksReserved>%u</ChunksReserved>\n",
1494                     indent, comp->chunk_reserved);
1495                 sbuf_printf(sb, "%s<StorageFree>%u%%</StorageFree>\n",
1496                     indent,
1497                     comp->chunk_next > 0 ? 100 -
1498                     ((comp->chunk_next + comp->chunk_reserved) * 100) /
1499                     comp->chunk_count : 100);
1500         } else {
1501                 /* For the whole thing */
1502                 u_int count, used, i;
1503                 off_t size;
1504
1505                 count = used = size = 0;
1506                 for (i = 0; i < sc->n_components; i++) {
1507                         if (sc->components[i].gcons != NULL) {
1508                                 count += sc->components[i].chunk_count;
1509                                 used += sc->components[i].chunk_next +
1510                                     sc->components[i].chunk_reserved;
1511                                 size += sc->components[i].gcons->
1512                                     provider->mediasize;
1513                         }
1514                 }
1515
1516                 sbuf_printf(sb, "%s<Status>"
1517                     "Components=%u, Online=%u</Status>\n", indent,
1518                     sc->n_components, virstor_valid_components(sc));
1519                 sbuf_printf(sb, "%s<State>%u%% physical free</State>\n",
1520                     indent, 100-(used * 100) / count);
1521                 sbuf_printf(sb, "%s<ChunkSize>%zu</ChunkSize>\n", indent,
1522                     sc->chunk_size);
1523                 sbuf_printf(sb, "%s<PhysicalFree>%u%%</PhysicalFree>\n",
1524                     indent, used > 0 ? 100 - (used * 100) / count : 100);
1525                 sbuf_printf(sb, "%s<ChunkPhysicalCount>%u</ChunkPhysicalCount>\n",
1526                     indent, count);
1527                 sbuf_printf(sb, "%s<ChunkVirtualCount>%zu</ChunkVirtualCount>\n",
1528                     indent, sc->chunk_count);
1529                 sbuf_printf(sb, "%s<PhysicalBacking>%zu%%</PhysicalBacking>\n",
1530                     indent,
1531                     (count * 100) / sc->chunk_count);
1532                 sbuf_printf(sb, "%s<PhysicalBackingSize>%jd</PhysicalBackingSize>\n",
1533                     indent, size);
1534                 sbuf_printf(sb, "%s<VirtualSize>%jd</VirtualSize>\n", indent,
1535                     sc->virsize);
1536         }
1537 }
1538
1539 /*
1540  * GEOM .done handler
1541  * Can't use standard handler because one requested IO may
1542  * fork into additional data IOs
1543  */
1544 static void
1545 g_virstor_done(struct bio *b)
1546 {
1547         struct g_virstor_softc *sc;
1548         struct bio *parent_b;
1549
1550         parent_b = b->bio_parent;
1551         sc = parent_b->bio_to->geom->softc;
1552
1553         if (b->bio_error != 0) {
1554                 LOG_MSG(LVL_ERROR, "Error %d for offset=%ju, length=%ju, %s",
1555                     b->bio_error, b->bio_offset, b->bio_length,
1556                     b->bio_to->name);
1557                 if (parent_b->bio_error == 0)
1558                         parent_b->bio_error = b->bio_error;
1559         }
1560
1561         parent_b->bio_inbed++;
1562         parent_b->bio_completed += b->bio_completed;
1563
1564         if (parent_b->bio_children == parent_b->bio_inbed) {
1565                 parent_b->bio_completed = parent_b->bio_length;
1566                 g_io_deliver(parent_b, parent_b->bio_error);
1567         }
1568         g_destroy_bio(b);
1569 }
1570
1571 /*
1572  * I/O starts here
1573  * Called in g_down thread
1574  */
1575 static void
1576 g_virstor_start(struct bio *b)
1577 {
1578         struct g_virstor_softc *sc;
1579         struct g_virstor_component *comp;
1580         struct bio *cb;
1581         struct g_provider *pp;
1582         char *addr;
1583         off_t offset, length;
1584         struct bio_queue_head bq;
1585         size_t chunk_size;      /* cached for convenience */
1586         u_int count;
1587
1588         pp = b->bio_to;
1589         sc = pp->geom->softc;
1590         KASSERT(sc != NULL, ("%s: no softc (error=%d, device=%s)", __func__,
1591             b->bio_to->error, b->bio_to->name));
1592
1593         LOG_REQ(LVL_MOREDEBUG, b, "%s", __func__);
1594
1595         switch (b->bio_cmd) {
1596         case BIO_READ:
1597         case BIO_WRITE:
1598         case BIO_DELETE:
1599                 break;
1600         default:
1601                 g_io_deliver(b, EOPNOTSUPP);
1602                 return;
1603         }
1604
1605         LOG_MSG(LVL_DEBUG2, "BIO arrived, size=%ju", b->bio_length);
1606         bioq_init(&bq);
1607
1608         chunk_size = sc->chunk_size;
1609         addr = b->bio_data;
1610         offset = b->bio_offset; /* virtual offset and length */
1611         length = b->bio_length;
1612
1613         while (length > 0) {
1614                 size_t chunk_index, in_chunk_offset, in_chunk_length;
1615                 struct virstor_map_entry *me;
1616
1617                 chunk_index = offset / chunk_size; /* round downwards */
1618                 in_chunk_offset = offset % chunk_size;
1619                 in_chunk_length = min(length, chunk_size - in_chunk_offset);
1620                 LOG_MSG(LVL_DEBUG, "Mapped %s(%ju, %ju) to (%zu,%zu,%zu)",
1621                     b->bio_cmd == BIO_READ ? "R" : "W",
1622                     offset, length,
1623                     chunk_index, in_chunk_offset, in_chunk_length);
1624                 me = &sc->map[chunk_index];
1625
1626                 if (b->bio_cmd == BIO_READ || b->bio_cmd == BIO_DELETE) {
1627                         if ((me->flags & VIRSTOR_MAP_ALLOCATED) == 0) {
1628                                 /* Reads from unallocated chunks return zeroed
1629                                  * buffers */
1630                                 if (b->bio_cmd == BIO_READ)
1631                                         bzero(addr, in_chunk_length);
1632                         } else {
1633                                 comp = &sc->components[me->provider_no];
1634
1635                                 cb = g_clone_bio(b);
1636                                 if (cb == NULL) {
1637                                         bioq_dismantle(&bq);
1638                                         if (b->bio_error == 0)
1639                                                 b->bio_error = ENOMEM;
1640                                         g_io_deliver(b, b->bio_error);
1641                                         return;
1642                                 }
1643                                 cb->bio_to = comp->gcons->provider;
1644                                 cb->bio_done = g_virstor_done;
1645                                 cb->bio_offset =
1646                                     (off_t)me->provider_chunk * (off_t)chunk_size
1647                                     + in_chunk_offset;
1648                                 cb->bio_length = in_chunk_length;
1649                                 cb->bio_data = addr;
1650                                 cb->bio_caller1 = comp;
1651                                 bioq_disksort(&bq, cb);
1652                         }
1653                 } else { /* handle BIO_WRITE */
1654                         KASSERT(b->bio_cmd == BIO_WRITE,
1655                             ("%s: Unknown command %d", __func__,
1656                             b->bio_cmd));
1657
1658                         if ((me->flags & VIRSTOR_MAP_ALLOCATED) == 0) {
1659                                 /* We have a virtual chunk, represented by
1660                                  * the "me" entry, but it's not yet allocated
1661                                  * (tied to) a physical chunk. So do it now. */
1662                                 struct virstor_map_entry *data_me;
1663                                 u_int phys_chunk, comp_no;
1664                                 off_t s_offset;
1665                                 int error;
1666
1667                                 error = allocate_chunk(sc, &comp, &comp_no,
1668                                     &phys_chunk);
1669                                 if (error != 0) {
1670                                         /* We cannot allocate a physical chunk
1671                                          * to satisfy this request, so we'll
1672                                          * delay it to when we can...
1673                                          * XXX: this will prevent the fs from
1674                                          * being umounted! */
1675                                         struct g_virstor_bio_q *biq;
1676                                         biq = malloc(sizeof *biq, M_GVIRSTOR,
1677                                             M_NOWAIT);
1678                                         if (biq == NULL) {
1679                                                 bioq_dismantle(&bq);
1680                                                 if (b->bio_error == 0)
1681                                                         b->bio_error = ENOMEM;
1682                                                 g_io_deliver(b, b->bio_error);
1683                                                 return;
1684                                         }
1685                                         biq->bio = b;
1686                                         mtx_lock(&sc->delayed_bio_q_mtx);
1687                                         STAILQ_INSERT_TAIL(&sc->delayed_bio_q,
1688                                             biq, linkage);
1689                                         mtx_unlock(&sc->delayed_bio_q_mtx);
1690                                         LOG_MSG(LVL_WARNING, "Delaying BIO "
1691                                             "(size=%ju) until free physical "
1692                                             "space can be found on %s",
1693                                             b->bio_length,
1694                                             sc->provider->name);
1695                                         return;
1696                                 }
1697                                 LOG_MSG(LVL_DEBUG, "Allocated chunk %u on %s "
1698                                     "for %s",
1699                                     phys_chunk,
1700                                     comp->gcons->provider->name,
1701                                     sc->provider->name);
1702
1703                                 me->provider_no = comp_no;
1704                                 me->provider_chunk = phys_chunk;
1705                                 me->flags |= VIRSTOR_MAP_ALLOCATED;
1706
1707                                 cb = g_clone_bio(b);
1708                                 if (cb == NULL) {
1709                                         me->flags &= ~VIRSTOR_MAP_ALLOCATED;
1710                                         me->provider_no = 0;
1711                                         me->provider_chunk = 0;
1712                                         bioq_dismantle(&bq);
1713                                         if (b->bio_error == 0)
1714                                                 b->bio_error = ENOMEM;
1715                                         g_io_deliver(b, b->bio_error);
1716                                         return;
1717                                 }
1718
1719                                 /* The allocation table is stored continuously
1720                                  * at the start of the drive. We need to
1721                                  * calculate the offset of the sector that holds
1722                                  * this map entry both on the drive and in the
1723                                  * map array.
1724                                  * sc_offset will end up pointing to the drive
1725                                  * sector. */
1726                                 s_offset = chunk_index * sizeof *me;
1727                                 s_offset = rounddown(s_offset, sc->sectorsize);
1728
1729                                 /* data_me points to map entry sector
1730                                  * in memory (analogous to offset) */
1731                                 data_me = &sc->map[rounddown(chunk_index,
1732                                     sc->me_per_sector)];
1733
1734                                 /* Commit sector with map entry to storage */
1735                                 cb->bio_to = sc->components[0].gcons->provider;
1736                                 cb->bio_done = g_virstor_done;
1737                                 cb->bio_offset = s_offset;
1738                                 cb->bio_data = (char *)data_me;
1739                                 cb->bio_length = sc->sectorsize;
1740                                 cb->bio_caller1 = &sc->components[0];
1741                                 bioq_disksort(&bq, cb);
1742                         }
1743
1744                         comp = &sc->components[me->provider_no];
1745                         cb = g_clone_bio(b);
1746                         if (cb == NULL) {
1747                                 bioq_dismantle(&bq);
1748                                 if (b->bio_error == 0)
1749                                         b->bio_error = ENOMEM;
1750                                 g_io_deliver(b, b->bio_error);
1751                                 return;
1752                         }
1753                         /* Finally, handle the data */
1754                         cb->bio_to = comp->gcons->provider;
1755                         cb->bio_done = g_virstor_done;
1756                         cb->bio_offset = (off_t)me->provider_chunk*(off_t)chunk_size +
1757                             in_chunk_offset;
1758                         cb->bio_length = in_chunk_length;
1759                         cb->bio_data = addr;
1760                         cb->bio_caller1 = comp;
1761                         bioq_disksort(&bq, cb);
1762                 }
1763                 addr += in_chunk_length;
1764                 length -= in_chunk_length;
1765                 offset += in_chunk_length;
1766         }
1767
1768         /* Fire off bio's here */
1769         count = 0;
1770         for (cb = bioq_first(&bq); cb != NULL; cb = bioq_first(&bq)) {
1771                 bioq_remove(&bq, cb);
1772                 LOG_REQ(LVL_MOREDEBUG, cb, "Firing request");
1773                 comp = cb->bio_caller1;
1774                 cb->bio_caller1 = NULL;
1775                 LOG_MSG(LVL_DEBUG, " firing bio, offset=%ju, length=%ju",
1776                     cb->bio_offset, cb->bio_length);
1777                 g_io_request(cb, comp->gcons);
1778                 count++;
1779         }
1780         if (count == 0) { /* We handled everything locally */
1781                 b->bio_completed = b->bio_length;
1782                 g_io_deliver(b, 0);
1783         }
1784
1785 }
1786
1787 /*
1788  * Allocate a chunk from a physical provider. Returns physical component,
1789  * chunk index relative to the component and the component's index.
1790  */
1791 static int
1792 allocate_chunk(struct g_virstor_softc *sc, struct g_virstor_component **comp,
1793     u_int *comp_no_p, u_int *chunk)
1794 {
1795         u_int comp_no;
1796
1797         KASSERT(sc->curr_component < sc->n_components,
1798             ("%s: Invalid curr_component: %u",  __func__, sc->curr_component));
1799
1800         comp_no = sc->curr_component;
1801         *comp = &sc->components[comp_no];
1802         dump_component(*comp);
1803         if ((*comp)->chunk_next >= (*comp)->chunk_count) {
1804                 /* This component is full. Allocate next component */
1805                 if (comp_no >= sc->n_components-1) {
1806                         LOG_MSG(LVL_ERROR, "All physical space allocated for %s",
1807                             sc->geom->name);
1808                         return (-1);
1809                 }
1810                 (*comp)->flags &= ~VIRSTOR_PROVIDER_CURRENT;
1811                 sc->curr_component = ++comp_no;
1812
1813                 *comp = &sc->components[comp_no];
1814                 if (comp_no >= sc->n_components - g_virstor_component_watermark-1)
1815                         LOG_MSG(LVL_WARNING, "Device %s running out of components "
1816                             "(switching to %u/%u: %s)", sc->geom->name,
1817                             comp_no+1, sc->n_components,
1818                             (*comp)->gcons->provider->name);
1819                 /* Take care not to overwrite reserved chunks */
1820                 if ( (*comp)->chunk_reserved > 0 &&
1821                     (*comp)->chunk_next < (*comp)->chunk_reserved)
1822                         (*comp)->chunk_next = (*comp)->chunk_reserved;
1823
1824                 (*comp)->flags |=
1825                     VIRSTOR_PROVIDER_ALLOCATED | VIRSTOR_PROVIDER_CURRENT;
1826                 dump_component(*comp);
1827                 *comp_no_p = comp_no;
1828                 *chunk = (*comp)->chunk_next++;
1829         } else {
1830                 *comp_no_p = comp_no;
1831                 *chunk = (*comp)->chunk_next++;
1832         }
1833         return (0);
1834 }
1835
1836 /* Dump a component */
1837 static void
1838 dump_component(struct g_virstor_component *comp)
1839 {
1840
1841         if (g_virstor_debug < LVL_DEBUG2)
1842                 return;
1843         printf("Component %d: %s\n", comp->index, comp->gcons->provider->name);
1844         printf("  chunk_count: %u\n", comp->chunk_count);
1845         printf("   chunk_next: %u\n", comp->chunk_next);
1846         printf("        flags: %u\n", comp->flags);
1847 }
1848
1849 #if 0
1850 /* Dump a map entry */
1851 static void
1852 dump_me(struct virstor_map_entry *me, unsigned int nr)
1853 {
1854         if (g_virstor_debug < LVL_DEBUG)
1855                 return;
1856         printf("VIRT. CHUNK #%d: ", nr);
1857         if ((me->flags & VIRSTOR_MAP_ALLOCATED) == 0)
1858                 printf("(unallocated)\n");
1859         else
1860                 printf("allocated at provider %u, provider_chunk %u\n",
1861                     me->provider_no, me->provider_chunk);
1862 }
1863 #endif
1864
1865 /*
1866  * Dismantle bio_queue and destroy its components
1867  */
1868 static void
1869 bioq_dismantle(struct bio_queue_head *bq)
1870 {
1871         struct bio *b;
1872
1873         for (b = bioq_first(bq); b != NULL; b = bioq_first(bq)) {
1874                 bioq_remove(bq, b);
1875                 g_destroy_bio(b);
1876         }
1877 }
1878
1879 /*
1880  * The function that shouldn't be called.
1881  * When this is called, the stack is already garbled because of
1882  * argument mismatch. There's nothing to do now but panic, which is
1883  * accidentally the whole purpose of this function.
1884  * Motivation: to guard from accidentally calling geom methods when
1885  * they shouldn't be called. (see g_..._taste)
1886  */
1887 static void
1888 invalid_call(void)
1889 {
1890         panic("invalid_call() has just been called. Something's fishy here.");
1891 }
1892
1893 DECLARE_GEOM_CLASS(g_virstor_class, g_virstor); /* Let there be light */
1894 MODULE_VERSION(geom_virstor, 0);