The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/geom/virstor/g_virstor.c

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    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: releng/10.0/sys/geom/virstor/g_virstor.c 239021 2012-08-03 20:24:16Z jimharris $");
   34 
   35 #include <sys/param.h>
   36 #include <sys/systm.h>
   37 #include <sys/kernel.h>
   38 #include <sys/module.h>
   39 #include <sys/lock.h>
   40 #include <sys/mutex.h>
   41 #include <sys/sx.h>
   42 #include <sys/bio.h>
   43 #include <sys/sbuf.h>
   44 #include <sys/sysctl.h>
   45 #include <sys/malloc.h>
   46 #include <sys/time.h>
   47 #include <sys/proc.h>
   48 #include <sys/kthread.h>
   49 #include <sys/mutex.h>
   50 #include <vm/uma.h>
   51 #include <geom/geom.h>
   52 
   53 #include <geom/virstor/g_virstor.h>
   54 #include <geom/virstor/g_virstor_md.h>
   55 
   56 FEATURE(g_virstor, "GEOM virtual storage support");
   57 
   58 /* Declare malloc(9) label */
   59 static MALLOC_DEFINE(M_GVIRSTOR, "gvirstor", "GEOM_VIRSTOR Data");
   60 
   61 /* GEOM class methods */
   62 static g_init_t g_virstor_init;
   63 static g_fini_t g_virstor_fini;
   64 static g_taste_t g_virstor_taste;
   65 static g_ctl_req_t g_virstor_config;
   66 static g_ctl_destroy_geom_t g_virstor_destroy_geom;
   67 
   68 /* Declare & initialize class structure ("geom class") */
   69 struct g_class g_virstor_class = {
   70         .name =         G_VIRSTOR_CLASS_NAME,
   71         .version =      G_VERSION,
   72         .init =         g_virstor_init,
   73         .fini =         g_virstor_fini,
   74         .taste =        g_virstor_taste,
   75         .ctlreq =       g_virstor_config,
   76         .destroy_geom = g_virstor_destroy_geom
   77         /* The .dumpconf and the rest are only usable for a geom instance, so
   78          * they will be set when such instance is created. */
   79 };
   80 
   81 /* Declare sysctl's and loader tunables */
   82 SYSCTL_DECL(_kern_geom);
   83 static SYSCTL_NODE(_kern_geom, OID_AUTO, virstor, CTLFLAG_RW, 0,
   84     "GEOM_GVIRSTOR information");
   85 
   86 static u_int g_virstor_debug = 2; /* XXX: lower to 2 when released to public */
   87 TUNABLE_INT("kern.geom.virstor.debug", &g_virstor_debug);
   88 SYSCTL_UINT(_kern_geom_virstor, OID_AUTO, debug, CTLFLAG_RW, &g_virstor_debug,
   89     0, "Debug level (2=production, 5=normal, 15=excessive)");
   90 
   91 static u_int g_virstor_chunk_watermark = 100;
   92 TUNABLE_INT("kern.geom.virstor.chunk_watermark", &g_virstor_chunk_watermark);
   93 SYSCTL_UINT(_kern_geom_virstor, OID_AUTO, chunk_watermark, CTLFLAG_RW,
   94     &g_virstor_chunk_watermark, 0,
   95     "Minimum number of free chunks before issuing administrative warning");
   96 
   97 static u_int g_virstor_component_watermark = 1;
   98 TUNABLE_INT("kern.geom.virstor.component_watermark",
   99     &g_virstor_component_watermark);
  100 SYSCTL_UINT(_kern_geom_virstor, OID_AUTO, component_watermark, CTLFLAG_RW,
  101     &g_virstor_component_watermark, 0,
  102     "Minimum number of free components before issuing administrative warning");
  103 
  104 static int read_metadata(struct g_consumer *, struct g_virstor_metadata *);
  105 static void write_metadata(struct g_consumer *, struct g_virstor_metadata *);
  106 static int clear_metadata(struct g_virstor_component *);
  107 static int add_provider_to_geom(struct g_virstor_softc *, struct g_provider *,
  108     struct g_virstor_metadata *);
  109 static struct g_geom *create_virstor_geom(struct g_class *,
  110     struct g_virstor_metadata *);
  111 static void virstor_check_and_run(struct g_virstor_softc *);
  112 static u_int virstor_valid_components(struct g_virstor_softc *);
  113 static int virstor_geom_destroy(struct g_virstor_softc *, boolean_t,
  114     boolean_t);
  115 static void remove_component(struct g_virstor_softc *,
  116     struct g_virstor_component *, boolean_t);
  117 static void bioq_dismantle(struct bio_queue_head *);
  118 static int allocate_chunk(struct g_virstor_softc *,
  119     struct g_virstor_component **, u_int *, u_int *);
  120 static void delay_destroy_consumer(void *, int);
  121 static void dump_component(struct g_virstor_component *comp);
  122 #if 0
  123 static void dump_me(struct virstor_map_entry *me, unsigned int nr);
  124 #endif
  125 
  126 static void virstor_ctl_stop(struct gctl_req *, struct g_class *);
  127 static void virstor_ctl_add(struct gctl_req *, struct g_class *);
  128 static void virstor_ctl_remove(struct gctl_req *, struct g_class *);
  129 static struct g_virstor_softc * virstor_find_geom(const struct g_class *,
  130     const char *);
  131 static void update_metadata(struct g_virstor_softc *);
  132 static void fill_metadata(struct g_virstor_softc *, struct g_virstor_metadata *,
  133     u_int, u_int);
  134 
  135 static void g_virstor_orphan(struct g_consumer *);
  136 static int g_virstor_access(struct g_provider *, int, int, int);
  137 static void g_virstor_start(struct bio *);
  138 static void g_virstor_dumpconf(struct sbuf *, const char *, struct g_geom *,
  139     struct g_consumer *, struct g_provider *);
  140 static void g_virstor_done(struct bio *);
  141 
  142 static void invalid_call(void);
  143 /*
  144  * Initialise GEOM class (per-class callback)
  145  */
  146 static void
  147 g_virstor_init(struct g_class *mp __unused)
  148 {
  149 
  150         /* Catch map struct size mismatch at compile time; Map entries must
  151          * fit into MAXPHYS exactly, with no wasted space. */
  152         CTASSERT(VIRSTOR_MAP_BLOCK_ENTRIES*VIRSTOR_MAP_ENTRY_SIZE == MAXPHYS);
  153 
  154         /* Init UMA zones, TAILQ's, other global vars */
  155 }
  156 
  157 /*
  158  * Finalise GEOM class (per-class callback)
  159  */
  160 static void
  161 g_virstor_fini(struct g_class *mp __unused)
  162 {
  163 
  164         /* Deinit UMA zones & global vars */
  165 }
  166 
  167 /*
  168  * Config (per-class callback)
  169  */
  170 static void
  171 g_virstor_config(struct gctl_req *req, struct g_class *cp, char const *verb)
  172 {
  173         uint32_t *version;
  174 
  175         g_topology_assert();
  176 
  177         version = gctl_get_paraml(req, "version", sizeof(*version));
  178         if (version == NULL) {
  179                 gctl_error(req, "Failed to get 'version' argument");
  180                 return;
  181         }
  182         if (*version != G_VIRSTOR_VERSION) {
  183                 gctl_error(req, "Userland and kernel versions out of sync");
  184                 return;
  185         }
  186 
  187         g_topology_unlock();
  188         if (strcmp(verb, "add") == 0)
  189                 virstor_ctl_add(req, cp);
  190         else if (strcmp(verb, "stop") == 0 || strcmp(verb, "destroy") == 0)
  191                 virstor_ctl_stop(req, cp);
  192         else if (strcmp(verb, "remove") == 0)
  193                 virstor_ctl_remove(req, cp);
  194         else
  195                 gctl_error(req, "unknown verb: '%s'", verb);
  196         g_topology_lock();
  197 }
  198 
  199 /*
  200  * "stop" verb from userland
  201  */
  202 static void
  203 virstor_ctl_stop(struct gctl_req *req, struct g_class *cp)
  204 {
  205         int *force, *nargs;
  206         int i;
  207 
  208         nargs = gctl_get_paraml(req, "nargs", sizeof *nargs);
  209         if (nargs == NULL) {
  210                 gctl_error(req, "Error fetching argument '%s'", "nargs");
  211                 return;
  212         }
  213         if (*nargs < 1) {
  214                 gctl_error(req, "Invalid number of arguments");
  215                 return;
  216         }
  217         force = gctl_get_paraml(req, "force", sizeof *force);
  218         if (force == NULL) {
  219                 gctl_error(req, "Error fetching argument '%s'", "force");
  220                 return;
  221         }
  222 
  223         g_topology_lock();
  224         for (i = 0; i < *nargs; i++) {
  225                 char param[8];
  226                 const char *name;
  227                 struct g_virstor_softc *sc;
  228                 int error;
  229 
  230                 sprintf(param, "arg%d", i);
  231                 name = gctl_get_asciiparam(req, param);
  232                 if (name == NULL) {
  233                         gctl_error(req, "No 'arg%d' argument", i);
  234                         g_topology_unlock();
  235                         return;
  236                 }
  237                 sc = virstor_find_geom(cp, name);
  238                 if (sc == NULL) {
  239                         gctl_error(req, "Don't know anything about '%s'", name);
  240                         g_topology_unlock();
  241                         return;
  242                 }
  243 
  244                 LOG_MSG(LVL_INFO, "Stopping %s by the userland command",
  245                     sc->geom->name);
  246                 update_metadata(sc);
  247                 if ((error = virstor_geom_destroy(sc, TRUE, TRUE)) != 0) {
  248                         LOG_MSG(LVL_ERROR, "Cannot destroy %s: %d",
  249                             sc->geom->name, error);
  250                 }
  251         }
  252         g_topology_unlock();
  253 }
  254 
  255 /*
  256  * "add" verb from userland - add new component(s) to the structure.
  257  * This will be done all at once in here, without going through the
  258  * .taste function for new components.
  259  */
  260 static void
  261 virstor_ctl_add(struct gctl_req *req, struct g_class *cp)
  262 {
  263         /* Note: while this is going on, I/O is being done on
  264          * the g_up and g_down threads. The idea is to make changes
  265          * to softc members in a way that can atomically activate
  266          * them all at once. */
  267         struct g_virstor_softc *sc;
  268         int *hardcode, *nargs;
  269         const char *geom_name;  /* geom to add a component to */
  270         struct g_consumer *fcp;
  271         struct g_virstor_bio_q *bq;
  272         u_int added;
  273         int error;
  274         int i;
  275 
  276         nargs = gctl_get_paraml(req, "nargs", sizeof(*nargs));
  277         if (nargs == NULL) {
  278                 gctl_error(req, "Error fetching argument '%s'", "nargs");
  279                 return;
  280         }
  281         if (*nargs < 2) {
  282                 gctl_error(req, "Invalid number of arguments");
  283                 return;
  284         }
  285         hardcode = gctl_get_paraml(req, "hardcode", sizeof(*hardcode));
  286         if (hardcode == NULL) {
  287                 gctl_error(req, "Error fetching argument '%s'", "hardcode");
  288                 return;
  289         }
  290 
  291         /* Find "our" geom */
  292         geom_name = gctl_get_asciiparam(req, "arg0");
  293         if (geom_name == NULL) {
  294                 gctl_error(req, "Error fetching argument '%s'", "geom_name (arg0)");
  295                 return;
  296         }
  297         sc = virstor_find_geom(cp, geom_name);
  298         if (sc == NULL) {
  299                 gctl_error(req, "Don't know anything about '%s'", geom_name);
  300                 return;
  301         }
  302 
  303         if (virstor_valid_components(sc) != sc->n_components) {
  304                 LOG_MSG(LVL_ERROR, "Cannot add components to incomplete "
  305                     "virstor %s", sc->geom->name);
  306                 gctl_error(req, "Virstor %s is incomplete", sc->geom->name);
  307                 return;
  308         }
  309 
  310         fcp = sc->components[0].gcons;
  311         added = 0;
  312         g_topology_lock();
  313         for (i = 1; i < *nargs; i++) {
  314                 struct g_virstor_metadata md;
  315                 char aname[8];
  316                 const char *prov_name;
  317                 struct g_provider *pp;
  318                 struct g_consumer *cp;
  319                 u_int nc;
  320                 u_int j;
  321 
  322                 snprintf(aname, sizeof aname, "arg%d", i);
  323                 prov_name = gctl_get_asciiparam(req, aname);
  324                 if (prov_name == NULL) {
  325                         gctl_error(req, "Error fetching argument '%s'", aname);
  326                         g_topology_unlock();
  327                         return;
  328                 }
  329                 if (strncmp(prov_name, _PATH_DEV, sizeof(_PATH_DEV) - 1) == 0)
  330                         prov_name += sizeof(_PATH_DEV) - 1;
  331 
  332                 pp = g_provider_by_name(prov_name);
  333                 if (pp == NULL) {
  334                         /* This is the most common error so be verbose about it */
  335                         if (added != 0) {
  336                                 gctl_error(req, "Invalid provider: '%s' (added"
  337                                     " %u components)", prov_name, added);
  338                                 update_metadata(sc);
  339                         } else {
  340                                 gctl_error(req, "Invalid provider: '%s'",
  341                                     prov_name);
  342                         }
  343                         g_topology_unlock();
  344                         return;
  345                 }
  346                 cp = g_new_consumer(sc->geom);
  347                 if (cp == NULL) {
  348                         gctl_error(req, "Cannot create consumer");
  349                         g_topology_unlock();
  350                         return;
  351                 }
  352                 error = g_attach(cp, pp);
  353                 if (error != 0) {
  354                         gctl_error(req, "Cannot attach a consumer to %s",
  355                             pp->name);
  356                         g_destroy_consumer(cp);
  357                         g_topology_unlock();
  358                         return;
  359                 }
  360                 if (fcp->acr != 0 || fcp->acw != 0 || fcp->ace != 0) {
  361                         error = g_access(cp, fcp->acr, fcp->acw, fcp->ace);
  362                         if (error != 0) {
  363                                 gctl_error(req, "Access request failed for %s",
  364                                     pp->name);
  365                                 g_destroy_consumer(cp);
  366                                 g_topology_unlock();
  367                                 return;
  368                         }
  369                 }
  370                 if (fcp->provider->sectorsize != pp->sectorsize) {
  371                         gctl_error(req, "Sector size doesn't fit for %s",
  372                             pp->name);
  373                         g_destroy_consumer(cp);
  374                         g_topology_unlock();
  375                         return;
  376                 }
  377                 for (j = 0; j < sc->n_components; j++) {
  378                         if (strcmp(sc->components[j].gcons->provider->name,
  379                             pp->name) == 0) {
  380                                 gctl_error(req, "Component %s already in %s",
  381                                     pp->name, sc->geom->name);
  382                                 g_destroy_consumer(cp);
  383                                 g_topology_unlock();
  384                                 return;
  385                         }
  386                 }
  387                 sc->components = realloc(sc->components,
  388                     sizeof(*sc->components) * (sc->n_components + 1),
  389                     M_GVIRSTOR, M_WAITOK);
  390 
  391                 nc = sc->n_components;
  392                 sc->components[nc].gcons = cp;
  393                 sc->components[nc].sc = sc;
  394                 sc->components[nc].index = nc;
  395                 sc->components[nc].chunk_count = cp->provider->mediasize /
  396                     sc->chunk_size;
  397                 sc->components[nc].chunk_next = 0;
  398                 sc->components[nc].chunk_reserved = 0;
  399 
  400                 if (sc->components[nc].chunk_count < 4) {
  401                         gctl_error(req, "Provider too small: %s",
  402                             cp->provider->name);
  403                         g_destroy_consumer(cp);
  404                         g_topology_unlock();
  405                         return;
  406                 }
  407                 fill_metadata(sc, &md, nc, *hardcode);
  408                 write_metadata(cp, &md);
  409                 /* The new component becomes visible when n_components is
  410                  * incremented */
  411                 sc->n_components++;
  412                 added++;
  413 
  414         }
  415         /* This call to update_metadata() is critical. In case there's a
  416          * power failure in the middle of it and some components are updated
  417          * while others are not, there will be trouble on next .taste() iff
  418          * a non-updated component is detected first */
  419         update_metadata(sc);
  420         g_topology_unlock();
  421         LOG_MSG(LVL_INFO, "Added %d component(s) to %s", added,
  422             sc->geom->name);
  423         /* Fire off BIOs previously queued because there wasn't any
  424          * physical space left. If the BIOs still can't be satisfied
  425          * they will again be added to the end of the queue (during
  426          * which the mutex will be recursed) */
  427         bq = malloc(sizeof(*bq), M_GVIRSTOR, M_WAITOK);
  428         bq->bio = NULL;
  429         mtx_lock(&sc->delayed_bio_q_mtx);
  430         /* First, insert a sentinel to the queue end, so we don't
  431          * end up in an infinite loop if there's still no free
  432          * space available. */
  433         STAILQ_INSERT_TAIL(&sc->delayed_bio_q, bq, linkage);
  434         while (!STAILQ_EMPTY(&sc->delayed_bio_q)) {
  435                 bq = STAILQ_FIRST(&sc->delayed_bio_q);
  436                 if (bq->bio != NULL) {
  437                         g_virstor_start(bq->bio);
  438                         STAILQ_REMOVE_HEAD(&sc->delayed_bio_q, linkage);
  439                         free(bq, M_GVIRSTOR);
  440                 } else {
  441                         STAILQ_REMOVE_HEAD(&sc->delayed_bio_q, linkage);
  442                         free(bq, M_GVIRSTOR);
  443                         break;
  444                 }
  445         }
  446         mtx_unlock(&sc->delayed_bio_q_mtx);
  447 
  448 }
  449 
  450 /*
  451  * Find a geom handled by the class
  452  */
  453 static struct g_virstor_softc *
  454 virstor_find_geom(const struct g_class *cp, const char *name)
  455 {
  456         struct g_geom *gp;
  457 
  458         LIST_FOREACH(gp, &cp->geom, geom) {
  459                 if (strcmp(name, gp->name) == 0)
  460                         return (gp->softc);
  461         }
  462         return (NULL);
  463 }
  464 
  465 /*
  466  * Update metadata on all components to reflect the current state
  467  * of these fields:
  468  *    - chunk_next
  469  *    - flags
  470  *    - md_count
  471  * Expects things to be set up so write_metadata() can work, i.e.
  472  * the topology lock must be held.
  473  */
  474 static void
  475 update_metadata(struct g_virstor_softc *sc)
  476 {
  477         struct g_virstor_metadata md;
  478         int n;
  479 
  480         if (virstor_valid_components(sc) != sc->n_components)
  481                 return; /* Incomplete device */
  482         LOG_MSG(LVL_DEBUG, "Updating metadata on components for %s",
  483             sc->geom->name);
  484         /* Update metadata on components */
  485         g_trace(G_T_TOPOLOGY, "%s(%s, %s)", __func__,
  486             sc->geom->class->name, sc->geom->name);
  487         g_topology_assert();
  488         for (n = 0; n < sc->n_components; n++) {
  489                 read_metadata(sc->components[n].gcons, &md);
  490                 md.chunk_next = sc->components[n].chunk_next;
  491                 md.flags = sc->components[n].flags;
  492                 md.md_count = sc->n_components;
  493                 write_metadata(sc->components[n].gcons, &md);
  494         }
  495 }
  496 
  497 /*
  498  * Fills metadata (struct md) from information stored in softc and the nc'th
  499  * component of virstor
  500  */
  501 static void
  502 fill_metadata(struct g_virstor_softc *sc, struct g_virstor_metadata *md,
  503     u_int nc, u_int hardcode)
  504 {
  505         struct g_virstor_component *c;
  506 
  507         bzero(md, sizeof *md);
  508         c = &sc->components[nc];
  509 
  510         strncpy(md->md_magic, G_VIRSTOR_MAGIC, sizeof md->md_magic);
  511         md->md_version = G_VIRSTOR_VERSION;
  512         strncpy(md->md_name, sc->geom->name, sizeof md->md_name);
  513         md->md_id = sc->id;
  514         md->md_virsize = sc->virsize;
  515         md->md_chunk_size = sc->chunk_size;
  516         md->md_count = sc->n_components;
  517 
  518         if (hardcode) {
  519                 strncpy(md->provider, c->gcons->provider->name,
  520                     sizeof md->provider);
  521         }
  522         md->no = nc;
  523         md->provsize = c->gcons->provider->mediasize;
  524         md->chunk_count = c->chunk_count;
  525         md->chunk_next = c->chunk_next;
  526         md->chunk_reserved = c->chunk_reserved;
  527         md->flags = c->flags;
  528 }
  529 
  530 /*
  531  * Remove a component from virstor device.
  532  * Can only be done if the component is unallocated.
  533  */
  534 static void
  535 virstor_ctl_remove(struct gctl_req *req, struct g_class *cp)
  536 {
  537         /* As this is executed in parallel to I/O, operations on virstor
  538          * structures must be as atomic as possible. */
  539         struct g_virstor_softc *sc;
  540         int *nargs;
  541         const char *geom_name;
  542         u_int removed;
  543         int i;
  544 
  545         nargs = gctl_get_paraml(req, "nargs", sizeof(*nargs));
  546         if (nargs == NULL) {
  547                 gctl_error(req, "Error fetching argument '%s'", "nargs");
  548                 return;
  549         }
  550         if (*nargs < 2) {
  551                 gctl_error(req, "Invalid number of arguments");
  552                 return;
  553         }
  554         /* Find "our" geom */
  555         geom_name = gctl_get_asciiparam(req, "arg0");
  556         if (geom_name == NULL) {
  557                 gctl_error(req, "Error fetching argument '%s'",
  558                     "geom_name (arg0)");
  559                 return;
  560         }
  561         sc = virstor_find_geom(cp, geom_name);
  562         if (sc == NULL) {
  563                 gctl_error(req, "Don't know anything about '%s'", geom_name);
  564                 return;
  565         }
  566 
  567         if (virstor_valid_components(sc) != sc->n_components) {
  568                 LOG_MSG(LVL_ERROR, "Cannot remove components from incomplete "
  569                     "virstor %s", sc->geom->name);
  570                 gctl_error(req, "Virstor %s is incomplete", sc->geom->name);
  571                 return;
  572         }
  573 
  574         removed = 0;
  575         for (i = 1; i < *nargs; i++) {
  576                 char param[8];
  577                 const char *prov_name;
  578                 int j, found;
  579                 struct g_virstor_component *newcomp, *compbak;
  580 
  581                 sprintf(param, "arg%d", i);
  582                 prov_name = gctl_get_asciiparam(req, param);
  583                 if (prov_name == NULL) {
  584                         gctl_error(req, "Error fetching argument '%s'", param);
  585                         return;
  586                 }
  587                 if (strncmp(prov_name, _PATH_DEV, sizeof(_PATH_DEV) - 1) == 0)
  588                         prov_name += sizeof(_PATH_DEV) - 1;
  589 
  590                 found = -1;
  591                 for (j = 0; j < sc->n_components; j++) {
  592                         if (strcmp(sc->components[j].gcons->provider->name,
  593                             prov_name) == 0) {
  594                                 found = j;
  595                                 break;
  596                         }
  597                 }
  598                 if (found == -1) {
  599                         LOG_MSG(LVL_ERROR, "No %s component in %s",
  600                             prov_name, sc->geom->name);
  601                         continue;
  602                 }
  603 
  604                 compbak = sc->components;
  605                 newcomp = malloc(sc->n_components * sizeof(*sc->components),
  606                     M_GVIRSTOR, M_WAITOK | M_ZERO);
  607                 bcopy(sc->components, newcomp, found * sizeof(*sc->components));
  608                 bcopy(&sc->components[found + 1], newcomp + found,
  609                     found * sizeof(*sc->components));
  610                 if ((sc->components[j].flags & VIRSTOR_PROVIDER_ALLOCATED) != 0) {
  611                         LOG_MSG(LVL_ERROR, "Allocated provider %s cannot be "
  612                             "removed from %s",
  613                             prov_name, sc->geom->name);
  614                         free(newcomp, M_GVIRSTOR);
  615                         /* We'll consider this non-fatal error */
  616                         continue;
  617                 }
  618                 /* Renumerate unallocated components */
  619                 for (j = 0; j < sc->n_components-1; j++) {
  620                         if ((sc->components[j].flags &
  621                             VIRSTOR_PROVIDER_ALLOCATED) == 0) {
  622                                 sc->components[j].index = j;
  623                         }
  624                 }
  625                 /* This is the critical section. If a component allocation
  626                  * event happens while both variables are not yet set,
  627                  * there will be trouble. Something will panic on encountering
  628                  * NULL sc->components[x].gcomp member.
  629                  * Luckily, component allocation happens very rarely and
  630                  * removing components is an abnormal action in any case. */
  631                 sc->components = newcomp;
  632                 sc->n_components--;
  633                 /* End critical section */
  634 
  635                 g_topology_lock();
  636                 if (clear_metadata(&compbak[found]) != 0) {
  637                         LOG_MSG(LVL_WARNING, "Trouble ahead: cannot clear "
  638                             "metadata on %s", prov_name);
  639                 }
  640                 g_detach(compbak[found].gcons);
  641                 g_destroy_consumer(compbak[found].gcons);
  642                 g_topology_unlock();
  643 
  644                 free(compbak, M_GVIRSTOR);
  645 
  646                 removed++;
  647         }
  648 
  649         /* This call to update_metadata() is critical. In case there's a
  650          * power failure in the middle of it and some components are updated
  651          * while others are not, there will be trouble on next .taste() iff
  652          * a non-updated component is detected first */
  653         g_topology_lock();
  654         update_metadata(sc);
  655         g_topology_unlock();
  656         LOG_MSG(LVL_INFO, "Removed %d component(s) from %s", removed,
  657             sc->geom->name);
  658 }
  659 
  660 /*
  661  * Clear metadata sector on component
  662  */
  663 static int
  664 clear_metadata(struct g_virstor_component *comp)
  665 {
  666         char *buf;
  667         int error;
  668 
  669         LOG_MSG(LVL_INFO, "Clearing metadata on %s",
  670             comp->gcons->provider->name);
  671         g_topology_assert();
  672         error = g_access(comp->gcons, 0, 1, 0);
  673         if (error != 0)
  674                 return (error);
  675         buf = malloc(comp->gcons->provider->sectorsize, M_GVIRSTOR,
  676             M_WAITOK | M_ZERO);
  677         error = g_write_data(comp->gcons,
  678             comp->gcons->provider->mediasize -
  679             comp->gcons->provider->sectorsize,
  680             buf,
  681             comp->gcons->provider->sectorsize);
  682         free(buf, M_GVIRSTOR);
  683         g_access(comp->gcons, 0, -1, 0);
  684         return (error);
  685 }
  686 
  687 /*
  688  * Destroy geom forcibly.
  689  */
  690 static int
  691 g_virstor_destroy_geom(struct gctl_req *req __unused, struct g_class *mp,
  692     struct g_geom *gp)
  693 {
  694         struct g_virstor_softc *sc;
  695         int exitval;
  696 
  697         sc = gp->softc;
  698         KASSERT(sc != NULL, ("%s: NULL sc", __func__));
  699         
  700         exitval = 0;
  701         LOG_MSG(LVL_DEBUG, "%s called for %s, sc=%p", __func__, gp->name,
  702             gp->softc);
  703 
  704         if (sc != NULL) {
  705 #ifdef INVARIANTS
  706                 char *buf;
  707                 int error;
  708                 off_t off;
  709                 int isclean, count;
  710                 int n;
  711 
  712                 LOG_MSG(LVL_INFO, "INVARIANTS detected");
  713                 LOG_MSG(LVL_INFO, "Verifying allocation "
  714                     "table for %s", sc->geom->name);
  715                 count = 0;
  716                 for (n = 0; n < sc->chunk_count; n++) {
  717                         if (sc->map[n].flags || VIRSTOR_MAP_ALLOCATED != 0)
  718                                 count++;
  719                 }
  720                 LOG_MSG(LVL_INFO, "Device %s has %d allocated chunks",
  721                     sc->geom->name, count);
  722                 n = off = count = 0;
  723                 isclean = 1;
  724                 if (virstor_valid_components(sc) != sc->n_components) {
  725                         /* This is a incomplete virstor device (not all
  726                          * components have been found) */
  727                         LOG_MSG(LVL_ERROR, "Device %s is incomplete",
  728                             sc->geom->name);
  729                         goto bailout;
  730                 }
  731                 error = g_access(sc->components[0].gcons, 1, 0, 0);
  732                 KASSERT(error == 0, ("%s: g_access failed (%d)", __func__,
  733                     error));
  734                 /* Compare the whole on-disk allocation table with what's
  735                  * currently in memory */
  736                 while (n < sc->chunk_count) {
  737                         buf = g_read_data(sc->components[0].gcons, off,
  738                             sc->sectorsize, &error);
  739                         KASSERT(buf != NULL, ("g_read_data returned NULL (%d) "
  740                             "for read at %jd", error, off));
  741                         if (bcmp(buf, &sc->map[n], sc->sectorsize) != 0) {
  742                                 LOG_MSG(LVL_ERROR, "ERROR in allocation table, "
  743                                     "entry %d, offset %jd", n, off);
  744                                 isclean = 0;
  745                                 count++;
  746                         }
  747                         n += sc->me_per_sector;
  748                         off += sc->sectorsize;
  749                         g_free(buf);
  750                 }
  751                 error = g_access(sc->components[0].gcons, -1, 0, 0);
  752                 KASSERT(error == 0, ("%s: g_access failed (%d) on exit",
  753                     __func__, error));
  754                 if (isclean != 1) {
  755                         LOG_MSG(LVL_ERROR, "ALLOCATION TABLE CORRUPTED FOR %s "
  756                             "(%d sectors don't match, max %zu allocations)",
  757                             sc->geom->name, count,
  758                             count * sc->me_per_sector);
  759                 } else {
  760                         LOG_MSG(LVL_INFO, "Allocation table ok for %s",
  761                             sc->geom->name);
  762                 }
  763 bailout:
  764 #endif
  765                 update_metadata(sc);
  766                 virstor_geom_destroy(sc, FALSE, FALSE);
  767                 exitval = EAGAIN;
  768         } else
  769                 exitval = 0;
  770         return (exitval);
  771 }
  772 
  773 /*
  774  * Taste event (per-class callback)
  775  * Examines a provider and creates geom instances if needed
  776  */
  777 static struct g_geom *
  778 g_virstor_taste(struct g_class *mp, struct g_provider *pp, int flags)
  779 {
  780         struct g_virstor_metadata md;
  781         struct g_geom *gp;
  782         struct g_consumer *cp;
  783         struct g_virstor_softc *sc;
  784         int error;
  785 
  786         g_trace(G_T_TOPOLOGY, "%s(%s, %s)", __func__, mp->name, pp->name);
  787         g_topology_assert();
  788         LOG_MSG(LVL_DEBUG, "Tasting %s", pp->name);
  789 
  790         /* We need a dummy geom to attach a consumer to the given provider */
  791         gp = g_new_geomf(mp, "virstor:taste.helper");
  792         gp->start = (void *)invalid_call;       /* XXX: hacked up so the        */
  793         gp->access = (void *)invalid_call;      /* compiler doesn't complain.   */
  794         gp->orphan = (void *)invalid_call;      /* I really want these to fail. */
  795 
  796         cp = g_new_consumer(gp);
  797         g_attach(cp, pp);
  798         error = read_metadata(cp, &md);
  799         g_detach(cp);
  800         g_destroy_consumer(cp);
  801         g_destroy_geom(gp);
  802 
  803         if (error != 0)
  804                 return (NULL);
  805 
  806         if (strcmp(md.md_magic, G_VIRSTOR_MAGIC) != 0)
  807                 return (NULL);
  808         if (md.md_version != G_VIRSTOR_VERSION) {
  809                 LOG_MSG(LVL_ERROR, "Kernel module version invalid "
  810                     "to handle %s (%s) : %d should be %d",
  811                     md.md_name, pp->name, md.md_version, G_VIRSTOR_VERSION);
  812                 return (NULL);
  813         }
  814         if (md.provsize != pp->mediasize)
  815                 return (NULL);
  816 
  817         /* If the provider name is hardcoded, use the offered provider only
  818          * if it's been offered with its proper name (the one used in
  819          * the label command). */
  820         if (md.provider[0] != '\0' &&
  821             !g_compare_names(md.provider, pp->name))
  822                 return (NULL);
  823 
  824         /* Iterate all geoms this class already knows about to see if a new
  825          * geom instance of this class needs to be created (in case the provider
  826          * is first from a (possibly) multi-consumer geom) or it just needs
  827          * to be added to an existing instance. */
  828         sc = NULL;
  829         gp = NULL;
  830         LIST_FOREACH(gp, &mp->geom, geom) {
  831                 sc = gp->softc;
  832                 if (sc == NULL)
  833                         continue;
  834                 if (strcmp(md.md_name, sc->geom->name) != 0)
  835                         continue;
  836                 if (md.md_id != sc->id)
  837                         continue;
  838                 break;
  839         }
  840         if (gp != NULL) { /* We found an existing geom instance; add to it */
  841                 LOG_MSG(LVL_INFO, "Adding %s to %s", pp->name, md.md_name);
  842                 error = add_provider_to_geom(sc, pp, &md);
  843                 if (error != 0) {
  844                         LOG_MSG(LVL_ERROR, "Error adding %s to %s (error %d)",
  845                             pp->name, md.md_name, error);
  846                         return (NULL);
  847                 }
  848         } else { /* New geom instance needs to be created */
  849                 gp = create_virstor_geom(mp, &md);
  850                 if (gp == NULL) {
  851                         LOG_MSG(LVL_ERROR, "Error creating new instance of "
  852                             "class %s: %s", mp->name, md.md_name);
  853                         LOG_MSG(LVL_DEBUG, "Error creating %s at %s",
  854                             md.md_name, pp->name);
  855                         return (NULL);
  856                 }
  857                 sc = gp->softc;
  858                 LOG_MSG(LVL_INFO, "Adding %s to %s (first found)", pp->name,
  859                     md.md_name);
  860                 error = add_provider_to_geom(sc, pp, &md);
  861                 if (error != 0) {
  862                         LOG_MSG(LVL_ERROR, "Error adding %s to %s (error %d)",
  863                             pp->name, md.md_name, error);
  864                         virstor_geom_destroy(sc, TRUE, FALSE);
  865                         return (NULL);
  866                 }
  867         }
  868 
  869         return (gp);
  870 }
  871 
  872 /*
  873  * Destroyes consumer passed to it in arguments. Used as a callback
  874  * on g_event queue.
  875  */
  876 static void
  877 delay_destroy_consumer(void *arg, int flags __unused)
  878 {
  879         struct g_consumer *c = arg;
  880         KASSERT(c != NULL, ("%s: invalid consumer", __func__));
  881         LOG_MSG(LVL_DEBUG, "Consumer %s destroyed with delay",
  882             c->provider->name);
  883         g_detach(c);
  884         g_destroy_consumer(c);
  885 }
  886 
  887 /*
  888  * Remove a component (consumer) from geom instance; If it's the first
  889  * component being removed, orphan the provider to announce geom's being
  890  * dismantled
  891  */
  892 static void
  893 remove_component(struct g_virstor_softc *sc, struct g_virstor_component *comp,
  894     boolean_t delay)
  895 {
  896         struct g_consumer *c;
  897 
  898         KASSERT(comp->gcons != NULL, ("Component with no consumer in %s",
  899             sc->geom->name));
  900         c = comp->gcons;
  901 
  902         comp->gcons = NULL;
  903         KASSERT(c->provider != NULL, ("%s: no provider", __func__));
  904         LOG_MSG(LVL_DEBUG, "Component %s removed from %s", c->provider->name,
  905             sc->geom->name);
  906         if (sc->provider != NULL) {
  907                 /* Whither, GEOM? */
  908                 sc->provider->flags |= G_PF_WITHER;
  909                 g_orphan_provider(sc->provider, ENXIO);
  910                 sc->provider = NULL;
  911                 LOG_MSG(LVL_INFO, "Removing provider %s", sc->geom->name);
  912         }
  913 
  914         if (c->acr > 0 || c->acw > 0 || c->ace > 0)
  915                 g_access(c, -c->acr, -c->acw, -c->ace);
  916         if (delay) {
  917                 /* Destroy consumer after it's tasted */
  918                 g_post_event(delay_destroy_consumer, c, M_WAITOK, NULL);
  919         } else {
  920                 g_detach(c);
  921                 g_destroy_consumer(c);
  922         }
  923 }
  924 
  925 /*
  926  * Destroy geom - called internally
  927  * See g_virstor_destroy_geom for the other one
  928  */
  929 static int
  930 virstor_geom_destroy(struct g_virstor_softc *sc, boolean_t force,
  931     boolean_t delay)
  932 {
  933         struct g_provider *pp;
  934         struct g_geom *gp;
  935         int n;
  936 
  937         g_topology_assert();
  938 
  939         if (sc == NULL)
  940                 return (ENXIO);
  941 
  942         pp = sc->provider;
  943         if (pp != NULL && (pp->acr != 0 || pp->acw != 0 || pp->ace != 0)) {
  944                 LOG_MSG(force ? LVL_WARNING : LVL_ERROR,
  945                     "Device %s is still open.", pp->name);
  946                 if (!force)
  947                         return (EBUSY);
  948         }
  949 
  950         for (n = 0; n < sc->n_components; n++) {
  951                 if (sc->components[n].gcons != NULL)
  952                         remove_component(sc, &sc->components[n], delay);
  953         }
  954 
  955         gp = sc->geom;
  956         gp->softc = NULL;
  957 
  958         KASSERT(sc->provider == NULL, ("Provider still exists for %s",
  959             gp->name));
  960 
  961         /* XXX: This might or might not work, since we're called with
  962          * the topology lock held. Also, it might panic the kernel if
  963          * the error'd BIO is in softupdates code. */
  964         mtx_lock(&sc->delayed_bio_q_mtx);
  965         while (!STAILQ_EMPTY(&sc->delayed_bio_q)) {
  966                 struct g_virstor_bio_q *bq;
  967                 bq = STAILQ_FIRST(&sc->delayed_bio_q);
  968                 bq->bio->bio_error = ENOSPC;
  969                 g_io_deliver(bq->bio, EIO);
  970                 STAILQ_REMOVE_HEAD(&sc->delayed_bio_q, linkage);
  971                 free(bq, M_GVIRSTOR);
  972         }
  973         mtx_unlock(&sc->delayed_bio_q_mtx);
  974         mtx_destroy(&sc->delayed_bio_q_mtx);
  975 
  976         free(sc->map, M_GVIRSTOR);
  977         free(sc->components, M_GVIRSTOR);
  978         bzero(sc, sizeof *sc);
  979         free(sc, M_GVIRSTOR);
  980 
  981         pp = LIST_FIRST(&gp->provider); /* We only offer one provider */
  982         if (pp == NULL || (pp->acr == 0 && pp->acw == 0 && pp->ace == 0))
  983                 LOG_MSG(LVL_DEBUG, "Device %s destroyed", gp->name);
  984 
  985         g_wither_geom(gp, ENXIO);
  986 
  987         return (0);
  988 }
  989 
  990 /*
  991  * Utility function: read metadata & decode. Wants topology lock to be
  992  * held.
  993  */
  994 static int
  995 read_metadata(struct g_consumer *cp, struct g_virstor_metadata *md)
  996 {
  997         struct g_provider *pp;
  998         char *buf;
  999         int error;
 1000 
 1001         g_topology_assert();
 1002         error = g_access(cp, 1, 0, 0);
 1003         if (error != 0)
 1004                 return (error);
 1005         pp = cp->provider;
 1006         g_topology_unlock();
 1007         buf = g_read_data(cp, pp->mediasize - pp->sectorsize, pp->sectorsize,
 1008             &error);
 1009         g_topology_lock();
 1010         g_access(cp, -1, 0, 0);
 1011         if (buf == NULL)
 1012                 return (error);
 1013 
 1014         virstor_metadata_decode(buf, md);
 1015         g_free(buf);
 1016 
 1017         return (0);
 1018 }
 1019 
 1020 /**
 1021  * Utility function: encode & write metadata. Assumes topology lock is
 1022  * held.
 1023  *
 1024  * There is no useful way of recovering from errors in this function,
 1025  * not involving panicking the kernel. If the metadata cannot be written
 1026  * the most we can do is notify the operator and hope he spots it and
 1027  * replaces the broken drive.
 1028  */
 1029 static void
 1030 write_metadata(struct g_consumer *cp, struct g_virstor_metadata *md)
 1031 {
 1032         struct g_provider *pp;
 1033         char *buf;
 1034         int error;
 1035 
 1036         KASSERT(cp != NULL && md != NULL && cp->provider != NULL,
 1037             ("Something's fishy in %s", __func__));
 1038         LOG_MSG(LVL_DEBUG, "Writing metadata on %s", cp->provider->name);
 1039         g_topology_assert();
 1040         error = g_access(cp, 0, 1, 0);
 1041         if (error != 0) {
 1042                 LOG_MSG(LVL_ERROR, "g_access(0,1,0) failed for %s: %d",
 1043                     cp->provider->name, error);
 1044                 return;
 1045         }
 1046         pp = cp->provider;
 1047 
 1048         buf = malloc(pp->sectorsize, M_GVIRSTOR, M_WAITOK);
 1049         virstor_metadata_encode(md, buf);
 1050         g_topology_unlock();
 1051         error = g_write_data(cp, pp->mediasize - pp->sectorsize, buf,
 1052             pp->sectorsize);
 1053         g_topology_lock();
 1054         g_access(cp, 0, -1, 0);
 1055         free(buf, M_GVIRSTOR);
 1056 
 1057         if (error != 0)
 1058                 LOG_MSG(LVL_ERROR, "Error %d writing metadata to %s",
 1059                     error, cp->provider->name);
 1060 }
 1061 
 1062 /*
 1063  * Creates a new instance of this GEOM class, initialise softc
 1064  */
 1065 static struct g_geom *
 1066 create_virstor_geom(struct g_class *mp, struct g_virstor_metadata *md)
 1067 {
 1068         struct g_geom *gp;
 1069         struct g_virstor_softc *sc;
 1070 
 1071         LOG_MSG(LVL_DEBUG, "Creating geom instance for %s (id=%u)",
 1072             md->md_name, md->md_id);
 1073 
 1074         if (md->md_count < 1 || md->md_chunk_size < 1 ||
 1075             md->md_virsize < md->md_chunk_size) {
 1076                 /* This is bogus configuration, and probably means data is
 1077                  * somehow corrupted. Panic, maybe? */
 1078                 LOG_MSG(LVL_ERROR, "Nonsensical metadata information for %s",
 1079                     md->md_name);
 1080                 return (NULL);
 1081         }
 1082 
 1083         /* Check if it's already created */
 1084         LIST_FOREACH(gp, &mp->geom, geom) {
 1085                 sc = gp->softc;
 1086                 if (sc != NULL && strcmp(sc->geom->name, md->md_name) == 0) {
 1087                         LOG_MSG(LVL_WARNING, "Geom %s already exists",
 1088                             md->md_name);
 1089                         if (sc->id != md->md_id) {
 1090                                 LOG_MSG(LVL_ERROR,
 1091                                     "Some stale or invalid components "
 1092                                     "exist for virstor device named %s. "
 1093                                     "You will need to <CLEAR> all stale "
 1094                                     "components and maybe reconfigure "
 1095                                     "the virstor device. Tune "
 1096                                     "kern.geom.virstor.debug sysctl up "
 1097                                     "for more information.",
 1098                                     sc->geom->name);
 1099                         }
 1100                         return (NULL);
 1101                 }
 1102         }
 1103         gp = g_new_geomf(mp, "%s", md->md_name);
 1104         gp->softc = NULL; /* to circumevent races that test softc */
 1105 
 1106         gp->start = g_virstor_start;
 1107         gp->spoiled = g_virstor_orphan;
 1108         gp->orphan = g_virstor_orphan;
 1109         gp->access = g_virstor_access;
 1110         gp->dumpconf = g_virstor_dumpconf;
 1111 
 1112         sc = malloc(sizeof(*sc), M_GVIRSTOR, M_WAITOK | M_ZERO);
 1113         sc->id = md->md_id;
 1114         sc->n_components = md->md_count;
 1115         sc->components = malloc(sizeof(struct g_virstor_component) * md->md_count,
 1116             M_GVIRSTOR, M_WAITOK | M_ZERO);
 1117         sc->chunk_size = md->md_chunk_size;
 1118         sc->virsize = md->md_virsize;
 1119         STAILQ_INIT(&sc->delayed_bio_q);
 1120         mtx_init(&sc->delayed_bio_q_mtx, "gvirstor_delayed_bio_q_mtx",
 1121             "gvirstor", MTX_DEF | MTX_RECURSE);
 1122 
 1123         sc->geom = gp;
 1124         sc->provider = NULL; /* virstor_check_and_run will create it */
 1125         gp->softc = sc;
 1126 
 1127         LOG_MSG(LVL_ANNOUNCE, "Device %s created", sc->geom->name);
 1128 
 1129         return (gp);
 1130 }
 1131 
 1132 /*
 1133  * Add provider to a GEOM class instance
 1134  */
 1135 static int
 1136 add_provider_to_geom(struct g_virstor_softc *sc, struct g_provider *pp,
 1137     struct g_virstor_metadata *md)
 1138 {
 1139         struct g_virstor_component *component;
 1140         struct g_consumer *cp, *fcp;
 1141         struct g_geom *gp;
 1142         int error;
 1143 
 1144         if (md->no >= sc->n_components)
 1145                 return (EINVAL);
 1146 
 1147         /* "Current" compontent */
 1148         component = &(sc->components[md->no]);
 1149         if (component->gcons != NULL)
 1150                 return (EEXIST);
 1151 
 1152         gp = sc->geom;
 1153         fcp = LIST_FIRST(&gp->consumer);
 1154 
 1155         cp = g_new_consumer(gp);
 1156         error = g_attach(cp, pp);
 1157 
 1158         if (error != 0) {
 1159                 g_destroy_consumer(cp);
 1160                 return (error);
 1161         }
 1162 
 1163         if (fcp != NULL) {
 1164                 if (fcp->provider->sectorsize != pp->sectorsize) {
 1165                         /* TODO: this can be made to work */
 1166                         LOG_MSG(LVL_ERROR, "Provider %s of %s has invalid "
 1167                             "sector size (%d)", pp->name, sc->geom->name,
 1168                             pp->sectorsize);
 1169                         return (EINVAL);
 1170                 }
 1171                 if (fcp->acr > 0 || fcp->acw || fcp->ace > 0) {
 1172                         /* Replicate access permissions from first "live" consumer
 1173                          * to the new one */
 1174                         error = g_access(cp, fcp->acr, fcp->acw, fcp->ace);
 1175                         if (error != 0) {
 1176                                 g_detach(cp);
 1177                                 g_destroy_consumer(cp);
 1178                                 return (error);
 1179                         }
 1180                 }
 1181         }
 1182 
 1183         /* Bring up a new component */
 1184         cp->private = component;
 1185         component->gcons = cp;
 1186         component->sc = sc;
 1187         component->index = md->no;
 1188         component->chunk_count = md->chunk_count;
 1189         component->chunk_next = md->chunk_next;
 1190         component->chunk_reserved = md->chunk_reserved;
 1191         component->flags = md->flags;
 1192 
 1193         LOG_MSG(LVL_DEBUG, "%s attached to %s", pp->name, sc->geom->name);
 1194 
 1195         virstor_check_and_run(sc);
 1196         return (0);
 1197 }
 1198 
 1199 /*
 1200  * Check if everything's ready to create the geom provider & device entry,
 1201  * create and start provider.
 1202  * Called ultimately by .taste, from g_event thread
 1203  */
 1204 static void
 1205 virstor_check_and_run(struct g_virstor_softc *sc)
 1206 {
 1207         off_t off;
 1208         size_t n, count;
 1209         int index;
 1210         int error;
 1211 
 1212         if (virstor_valid_components(sc) != sc->n_components)
 1213                 return;
 1214 
 1215         if (virstor_valid_components(sc) == 0) {
 1216                 /* This is actually a candidate for panic() */
 1217                 LOG_MSG(LVL_ERROR, "No valid components for %s?",
 1218                     sc->provider->name);
 1219                 return;
 1220         }
 1221 
 1222         sc->sectorsize = sc->components[0].gcons->provider->sectorsize;
 1223 
 1224         /* Initialise allocation map from the first consumer */
 1225         sc->chunk_count = sc->virsize / sc->chunk_size;
 1226         if (sc->chunk_count * (off_t)sc->chunk_size != sc->virsize) {
 1227                 LOG_MSG(LVL_WARNING, "Device %s truncated to %ju bytes",
 1228                     sc->provider->name,
 1229                     sc->chunk_count * (off_t)sc->chunk_size);
 1230         }
 1231         sc->map_size = sc->chunk_count * sizeof *(sc->map);
 1232         /* The following allocation is in order of 4MB - 8MB */
 1233         sc->map = malloc(sc->map_size, M_GVIRSTOR, M_WAITOK);
 1234         KASSERT(sc->map != NULL, ("%s: Memory allocation error (%zu bytes) for %s",
 1235             __func__, sc->map_size, sc->provider->name));
 1236         sc->map_sectors = sc->map_size / sc->sectorsize;
 1237 
 1238         count = 0;
 1239         for (n = 0; n < sc->n_components; n++)
 1240                 count += sc->components[n].chunk_count;
 1241         LOG_MSG(LVL_INFO, "Device %s has %zu physical chunks and %zu virtual "
 1242             "(%zu KB chunks)",
 1243             sc->geom->name, count, sc->chunk_count, sc->chunk_size / 1024);
 1244 
 1245         error = g_access(sc->components[0].gcons, 1, 0, 0);
 1246         if (error != 0) {
 1247                 LOG_MSG(LVL_ERROR, "Cannot acquire read access for %s to "
 1248                     "read allocation map for %s",
 1249                     sc->components[0].gcons->provider->name,
 1250                     sc->geom->name);
 1251                 return;
 1252         }
 1253         /* Read in the allocation map */
 1254         LOG_MSG(LVL_DEBUG, "Reading map for %s from %s", sc->geom->name,
 1255             sc->components[0].gcons->provider->name);
 1256         off = count = n = 0;
 1257         while (count < sc->map_size) {
 1258                 struct g_virstor_map_entry *mapbuf;
 1259                 size_t bs;
 1260 
 1261                 bs = MIN(MAXPHYS, sc->map_size - count);
 1262                 if (bs % sc->sectorsize != 0) {
 1263                         /* Check for alignment errors */
 1264                         bs = (bs / sc->sectorsize) * sc->sectorsize;
 1265                         if (bs == 0)
 1266                                 break;
 1267                         LOG_MSG(LVL_ERROR, "Trouble: map is not sector-aligned "
 1268                             "for %s on %s", sc->geom->name,
 1269                             sc->components[0].gcons->provider->name);
 1270                 }
 1271                 mapbuf = g_read_data(sc->components[0].gcons, off, bs, &error);
 1272                 if (mapbuf == NULL) {
 1273                         free(sc->map, M_GVIRSTOR);
 1274                         LOG_MSG(LVL_ERROR, "Error reading allocation map "
 1275                             "for %s from %s (offset %ju) (error %d)",
 1276                             sc->geom->name,
 1277                             sc->components[0].gcons->provider->name,
 1278                             off, error);
 1279                         return;
 1280                 }
 1281 
 1282                 bcopy(mapbuf, &sc->map[n], bs);
 1283                 off += bs;
 1284                 count += bs;
 1285                 n += bs / sizeof *(sc->map);
 1286                 g_free(mapbuf);
 1287         }
 1288         g_access(sc->components[0].gcons, -1, 0, 0);
 1289         LOG_MSG(LVL_DEBUG, "Read map for %s", sc->geom->name);
 1290 
 1291         /* find first component with allocatable chunks */
 1292         index = -1;
 1293         for (n = 0; n < sc->n_components; n++) {
 1294                 if (sc->components[n].chunk_next <
 1295                     sc->components[n].chunk_count) {
 1296                         index = n;
 1297                         break;
 1298                 }
 1299         }
 1300         if (index == -1)
 1301                 /* not found? set it to the last component and handle it
 1302                  * later */
 1303                 index = sc->n_components - 1;
 1304 
 1305         if (index >= sc->n_components - g_virstor_component_watermark - 1) {
 1306                 LOG_MSG(LVL_WARNING, "Device %s running out of components "
 1307                     "(%d/%u: %s)", sc->geom->name,
 1308                     index+1,
 1309                     sc->n_components,
 1310                     sc->components[index].gcons->provider->name);
 1311         }
 1312         sc->curr_component = index;
 1313 
 1314         if (sc->components[index].chunk_next >=
 1315             sc->components[index].chunk_count - g_virstor_chunk_watermark) {
 1316                 LOG_MSG(LVL_WARNING,
 1317                     "Component %s of %s is running out of free space "
 1318                     "(%u chunks left)",
 1319                     sc->components[index].gcons->provider->name,
 1320                     sc->geom->name, sc->components[index].chunk_count -
 1321                     sc->components[index].chunk_next);
 1322         }
 1323 
 1324         sc->me_per_sector = sc->sectorsize / sizeof *(sc->map);
 1325         if (sc->sectorsize % sizeof *(sc->map) != 0) {
 1326                 LOG_MSG(LVL_ERROR,
 1327                     "%s: Map entries don't fit exactly in a sector (%s)",
 1328                     __func__, sc->geom->name);
 1329                 return;
 1330         }
 1331 
 1332         /* Recalculate allocated chunks in components & at the same time
 1333          * verify map data is sane. We could trust metadata on this, but
 1334          * we want to make sure. */
 1335         for (n = 0; n < sc->n_components; n++)
 1336                 sc->components[n].chunk_next = sc->components[n].chunk_reserved;
 1337 
 1338         for (n = 0; n < sc->chunk_count; n++) {
 1339                 if (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                         LOG_MSG(LVL_ERROR, "%s: Invalid entry %u in map for %s",
 1343                             __func__, (u_int)n, sc->geom->name);
 1344                         LOG_MSG(LVL_ERROR, "%s: provider_no: %u, n_components: %u"
 1345                             " provider_chunk: %u, chunk_count: %u", __func__,
 1346                             sc->map[n].provider_no, sc->n_components,
 1347                             sc->map[n].provider_chunk,
 1348                             sc->components[sc->map[n].provider_no].chunk_count);
 1349                         return;
 1350                 }
 1351                 if (sc->map[n].flags & VIRSTOR_MAP_ALLOCATED)
 1352                         sc->components[sc->map[n].provider_no].chunk_next++;
 1353         }
 1354 
 1355         sc->provider = g_new_providerf(sc->geom, "virstor/%s",
 1356             sc->geom->name);
 1357 
 1358         sc->provider->sectorsize = sc->sectorsize;
 1359         sc->provider->mediasize = sc->virsize;
 1360         g_error_provider(sc->provider, 0);
 1361 
 1362         LOG_MSG(LVL_INFO, "%s activated", sc->provider->name);
 1363         LOG_MSG(LVL_DEBUG, "%s starting with current component %u, starting "
 1364             "chunk %u", sc->provider->name, sc->curr_component,
 1365             sc->components[sc->curr_component].chunk_next);
 1366 }
 1367 
 1368 /*
 1369  * Returns count of active providers in this geom instance
 1370  */
 1371 static u_int
 1372 virstor_valid_components(struct g_virstor_softc *sc)
 1373 {
 1374         unsigned int nc, i;
 1375 
 1376         nc = 0;
 1377         KASSERT(sc != NULL, ("%s: softc is NULL", __func__));
 1378         KASSERT(sc->components != NULL, ("%s: sc->components is NULL", __func__));
 1379         for (i = 0; i < sc->n_components; i++)
 1380                 if (sc->components[i].gcons != NULL)
 1381                         nc++;
 1382         return (nc);
 1383 }
 1384 
 1385 /*
 1386  * Called when the consumer gets orphaned (?)
 1387  */
 1388 static void
 1389 g_virstor_orphan(struct g_consumer *cp)
 1390 {
 1391         struct g_virstor_softc *sc;
 1392         struct g_virstor_component *comp;
 1393         struct g_geom *gp;
 1394 
 1395         g_topology_assert();
 1396         gp = cp->geom;
 1397         sc = gp->softc;
 1398         if (sc == NULL)
 1399                 return;
 1400 
 1401         comp = cp->private;
 1402         KASSERT(comp != NULL, ("%s: No component in private part of consumer",
 1403             __func__));
 1404         remove_component(sc, comp, FALSE);
 1405         if (virstor_valid_components(sc) == 0)
 1406                 virstor_geom_destroy(sc, TRUE, FALSE);
 1407 }
 1408 
 1409 /*
 1410  * Called to notify geom when it's been opened, and for what intent
 1411  */
 1412 static int
 1413 g_virstor_access(struct g_provider *pp, int dr, int dw, int de)
 1414 {
 1415         struct g_consumer *c;
 1416         struct g_virstor_softc *sc;
 1417         struct g_geom *gp;
 1418         int error;
 1419 
 1420         KASSERT(pp != NULL, ("%s: NULL provider", __func__));
 1421         gp = pp->geom;
 1422         KASSERT(gp != NULL, ("%s: NULL geom", __func__));
 1423         sc = gp->softc;
 1424 
 1425         if (sc == NULL) {
 1426                 /* It seems that .access can be called with negative dr,dw,dx
 1427                  * in this case but I want to check for myself */
 1428                 LOG_MSG(LVL_WARNING, "access(%d, %d, %d) for %s",
 1429                     dr, dw, de, pp->name);
 1430                 /* This should only happen when geom is withered so
 1431                  * allow only negative requests */
 1432                 KASSERT(dr <= 0 && dw <= 0 && de <= 0,
 1433                     ("%s: Positive access for %s", __func__, pp->name));
 1434                 if (pp->acr + dr == 0 && pp->acw + dw == 0 && pp->ace + de == 0)
 1435                         LOG_MSG(LVL_DEBUG, "Device %s definitely destroyed",
 1436                             pp->name);
 1437                 return (0);
 1438         }
 1439 
 1440         /* Grab an exclusive bit to propagate on our consumers on first open */
 1441         if (pp->acr == 0 && pp->acw == 0 && pp->ace == 0)
 1442                 de++;
 1443         /* ... drop it on close */
 1444         if (pp->acr + dr == 0 && pp->acw + dw == 0 && pp->ace + de == 0) {
 1445                 de--;
 1446                 update_metadata(sc);    /* Writes statistical information */
 1447         }
 1448 
 1449         error = ENXIO;
 1450         LIST_FOREACH(c, &gp->consumer, consumer) {
 1451                 KASSERT(c != NULL, ("%s: consumer is NULL", __func__));
 1452                 error = g_access(c, dr, dw, de);
 1453                 if (error != 0) {
 1454                         struct g_consumer *c2;
 1455 
 1456                         /* Backout earlier changes */
 1457                         LIST_FOREACH(c2, &gp->consumer, consumer) {
 1458                                 if (c2 == c) /* all eariler components fixed */
 1459                                         return (error);
 1460                                 g_access(c2, -dr, -dw, -de);
 1461                         }
 1462                 }
 1463         }
 1464 
 1465         return (error);
 1466 }
 1467 
 1468 /*
 1469  * Generate XML dump of current state
 1470  */
 1471 static void
 1472 g_virstor_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp,
 1473     struct g_consumer *cp, struct g_provider *pp)
 1474 {
 1475         struct g_virstor_softc *sc;
 1476 
 1477         g_topology_assert();
 1478         sc = gp->softc;
 1479 
 1480         if (sc == NULL || pp != NULL)
 1481                 return;
 1482 
 1483         if (cp != NULL) {
 1484                 /* For each component */
 1485                 struct g_virstor_component *comp;
 1486 
 1487                 comp = cp->private;
 1488                 if (comp == NULL)
 1489                         return;
 1490                 sbuf_printf(sb, "%s<ComponentIndex>%u</ComponentIndex>\n",
 1491                     indent, comp->index);
 1492                 sbuf_printf(sb, "%s<ChunkCount>%u</ChunkCount>\n",
 1493                     indent, comp->chunk_count);
 1494                 sbuf_printf(sb, "%s<ChunksUsed>%u</ChunksUsed>\n",
 1495                     indent, comp->chunk_next);
 1496                 sbuf_printf(sb, "%s<ChunksReserved>%u</ChunksReserved>\n",
 1497                     indent, comp->chunk_reserved);
 1498                 sbuf_printf(sb, "%s<StorageFree>%u%%</StorageFree>\n",
 1499                     indent,
 1500                     comp->chunk_next > 0 ? 100 -
 1501                     ((comp->chunk_next + comp->chunk_reserved) * 100) /
 1502                     comp->chunk_count : 100);
 1503         } else {
 1504                 /* For the whole thing */
 1505                 u_int count, used, i;
 1506                 off_t size;
 1507 
 1508                 count = used = size = 0;
 1509                 for (i = 0; i < sc->n_components; i++) {
 1510                         if (sc->components[i].gcons != NULL) {
 1511                                 count += sc->components[i].chunk_count;
 1512                                 used += sc->components[i].chunk_next +
 1513                                     sc->components[i].chunk_reserved;
 1514                                 size += sc->components[i].gcons->
 1515                                     provider->mediasize;
 1516                         }
 1517                 }
 1518 
 1519                 sbuf_printf(sb, "%s<Status>"
 1520                     "Components=%u, Online=%u</Status>\n", indent,
 1521                     sc->n_components, virstor_valid_components(sc));
 1522                 sbuf_printf(sb, "%s<State>%u%% physical free</State>\n",
 1523                     indent, 100-(used * 100) / count);
 1524                 sbuf_printf(sb, "%s<ChunkSize>%zu</ChunkSize>\n", indent,
 1525                     sc->chunk_size);
 1526                 sbuf_printf(sb, "%s<PhysicalFree>%u%%</PhysicalFree>\n",
 1527                     indent, used > 0 ? 100 - (used * 100) / count : 100);
 1528                 sbuf_printf(sb, "%s<ChunkPhysicalCount>%u</ChunkPhysicalCount>\n",
 1529                     indent, count);
 1530                 sbuf_printf(sb, "%s<ChunkVirtualCount>%zu</ChunkVirtualCount>\n",
 1531                     indent, sc->chunk_count);
 1532                 sbuf_printf(sb, "%s<PhysicalBacking>%zu%%</PhysicalBacking>\n",
 1533                     indent,
 1534                     (count * 100) / sc->chunk_count);
 1535                 sbuf_printf(sb, "%s<PhysicalBackingSize>%jd</PhysicalBackingSize>\n",
 1536                     indent, size);
 1537                 sbuf_printf(sb, "%s<VirtualSize>%jd</VirtualSize>\n", indent,
 1538                     sc->virsize);
 1539         }
 1540 }
 1541 
 1542 /*
 1543  * GEOM .done handler
 1544  * Can't use standard handler because one requested IO may
 1545  * fork into additional data IOs
 1546  */
 1547 static void
 1548 g_virstor_done(struct bio *b)
 1549 {
 1550         struct g_virstor_softc *sc;
 1551         struct bio *parent_b;
 1552 
 1553         parent_b = b->bio_parent;
 1554         sc = parent_b->bio_to->geom->softc;
 1555 
 1556         if (b->bio_error != 0) {
 1557                 LOG_MSG(LVL_ERROR, "Error %d for offset=%ju, length=%ju, %s",
 1558                     b->bio_error, b->bio_offset, b->bio_length,
 1559                     b->bio_to->name);
 1560                 if (parent_b->bio_error == 0)
 1561                         parent_b->bio_error = b->bio_error;
 1562         }
 1563 
 1564         parent_b->bio_inbed++;
 1565         parent_b->bio_completed += b->bio_completed;
 1566 
 1567         if (parent_b->bio_children == parent_b->bio_inbed) {
 1568                 parent_b->bio_completed = parent_b->bio_length;
 1569                 g_io_deliver(parent_b, parent_b->bio_error);
 1570         }
 1571         g_destroy_bio(b);
 1572 }
 1573 
 1574 /*
 1575  * I/O starts here
 1576  * Called in g_down thread
 1577  */
 1578 static void
 1579 g_virstor_start(struct bio *b)
 1580 {
 1581         struct g_virstor_softc *sc;
 1582         struct g_virstor_component *comp;
 1583         struct bio *cb;
 1584         struct g_provider *pp;
 1585         char *addr;
 1586         off_t offset, length;
 1587         struct bio_queue_head bq;
 1588         size_t chunk_size;      /* cached for convenience */
 1589         u_int count;
 1590 
 1591         pp = b->bio_to;
 1592         sc = pp->geom->softc;
 1593         KASSERT(sc != NULL, ("%s: no softc (error=%d, device=%s)", __func__,
 1594             b->bio_to->error, b->bio_to->name));
 1595 
 1596         LOG_REQ(LVL_MOREDEBUG, b, "%s", __func__);
 1597 
 1598         switch (b->bio_cmd) {
 1599         case BIO_READ:
 1600         case BIO_WRITE:
 1601         case BIO_DELETE:
 1602                 break;
 1603         default:
 1604                 g_io_deliver(b, EOPNOTSUPP);
 1605                 return;
 1606         }
 1607 
 1608         LOG_MSG(LVL_DEBUG2, "BIO arrived, size=%ju", b->bio_length);
 1609         bioq_init(&bq);
 1610 
 1611         chunk_size = sc->chunk_size;
 1612         addr = b->bio_data;
 1613         offset = b->bio_offset; /* virtual offset and length */
 1614         length = b->bio_length;
 1615 
 1616         while (length > 0) {
 1617                 size_t chunk_index, in_chunk_offset, in_chunk_length;
 1618                 struct virstor_map_entry *me;
 1619 
 1620                 chunk_index = offset / chunk_size; /* round downwards */
 1621                 in_chunk_offset = offset % chunk_size;
 1622                 in_chunk_length = min(length, chunk_size - in_chunk_offset);
 1623                 LOG_MSG(LVL_DEBUG, "Mapped %s(%ju, %ju) to (%zu,%zu,%zu)",
 1624                     b->bio_cmd == BIO_READ ? "R" : "W",
 1625                     offset, length,
 1626                     chunk_index, in_chunk_offset, in_chunk_length);
 1627                 me = &sc->map[chunk_index];
 1628 
 1629                 if (b->bio_cmd == BIO_READ || b->bio_cmd == BIO_DELETE) {
 1630                         if ((me->flags & VIRSTOR_MAP_ALLOCATED) == 0) {
 1631                                 /* Reads from unallocated chunks return zeroed
 1632                                  * buffers */
 1633                                 if (b->bio_cmd == BIO_READ)
 1634                                         bzero(addr, in_chunk_length);
 1635                         } else {
 1636                                 comp = &sc->components[me->provider_no];
 1637 
 1638                                 cb = g_clone_bio(b);
 1639                                 if (cb == NULL) {
 1640                                         bioq_dismantle(&bq);
 1641                                         if (b->bio_error == 0)
 1642                                                 b->bio_error = ENOMEM;
 1643                                         g_io_deliver(b, b->bio_error);
 1644                                         return;
 1645                                 }
 1646                                 cb->bio_to = comp->gcons->provider;
 1647                                 cb->bio_done = g_virstor_done;
 1648                                 cb->bio_offset =
 1649                                     (off_t)me->provider_chunk * (off_t)chunk_size
 1650                                     + in_chunk_offset;
 1651                                 cb->bio_length = in_chunk_length;
 1652                                 cb->bio_data = addr;
 1653                                 cb->bio_caller1 = comp;
 1654                                 bioq_disksort(&bq, cb);
 1655                         }
 1656                 } else { /* handle BIO_WRITE */
 1657                         KASSERT(b->bio_cmd == BIO_WRITE,
 1658                             ("%s: Unknown command %d", __func__,
 1659                             b->bio_cmd));
 1660 
 1661                         if ((me->flags & VIRSTOR_MAP_ALLOCATED) == 0) {
 1662                                 /* We have a virtual chunk, represented by
 1663                                  * the "me" entry, but it's not yet allocated
 1664                                  * (tied to) a physical chunk. So do it now. */
 1665                                 struct virstor_map_entry *data_me;
 1666                                 u_int phys_chunk, comp_no;
 1667                                 off_t s_offset;
 1668                                 int error;
 1669 
 1670                                 error = allocate_chunk(sc, &comp, &comp_no,
 1671                                     &phys_chunk);
 1672                                 if (error != 0) {
 1673                                         /* We cannot allocate a physical chunk
 1674                                          * to satisfy this request, so we'll
 1675                                          * delay it to when we can...
 1676                                          * XXX: this will prevent the fs from
 1677                                          * being umounted! */
 1678                                         struct g_virstor_bio_q *biq;
 1679                                         biq = malloc(sizeof *biq, M_GVIRSTOR,
 1680                                             M_NOWAIT);
 1681                                         if (biq == NULL) {
 1682                                                 bioq_dismantle(&bq);
 1683                                                 if (b->bio_error == 0)
 1684                                                         b->bio_error = ENOMEM;
 1685                                                 g_io_deliver(b, b->bio_error);
 1686                                                 return;
 1687                                         }
 1688                                         biq->bio = b;
 1689                                         mtx_lock(&sc->delayed_bio_q_mtx);
 1690                                         STAILQ_INSERT_TAIL(&sc->delayed_bio_q,
 1691                                             biq, linkage);
 1692                                         mtx_unlock(&sc->delayed_bio_q_mtx);
 1693                                         LOG_MSG(LVL_WARNING, "Delaying BIO "
 1694                                             "(size=%ju) until free physical "
 1695                                             "space can be found on %s",
 1696                                             b->bio_length,
 1697                                             sc->provider->name);
 1698                                         return;
 1699                                 }
 1700                                 LOG_MSG(LVL_DEBUG, "Allocated chunk %u on %s "
 1701                                     "for %s",
 1702                                     phys_chunk,
 1703                                     comp->gcons->provider->name,
 1704                                     sc->provider->name);
 1705 
 1706                                 me->provider_no = comp_no;
 1707                                 me->provider_chunk = phys_chunk;
 1708                                 me->flags |= VIRSTOR_MAP_ALLOCATED;
 1709 
 1710                                 cb = g_clone_bio(b);
 1711                                 if (cb == NULL) {
 1712                                         me->flags &= ~VIRSTOR_MAP_ALLOCATED;
 1713                                         me->provider_no = 0;
 1714                                         me->provider_chunk = 0;
 1715                                         bioq_dismantle(&bq);
 1716                                         if (b->bio_error == 0)
 1717                                                 b->bio_error = ENOMEM;
 1718                                         g_io_deliver(b, b->bio_error);
 1719                                         return;
 1720                                 }
 1721 
 1722                                 /* The allocation table is stored continuously
 1723                                  * at the start of the drive. We need to
 1724                                  * calculate the offset of the sector that holds
 1725                                  * this map entry both on the drive and in the
 1726                                  * map array.
 1727                                  * sc_offset will end up pointing to the drive
 1728                                  * sector. */
 1729                                 s_offset = chunk_index * sizeof *me;
 1730                                 s_offset = (s_offset / sc->sectorsize) *
 1731                                     sc->sectorsize;
 1732 
 1733                                 /* data_me points to map entry sector
 1734                                  * in memory (analoguos to offset) */
 1735                                 data_me = &sc->map[(chunk_index /
 1736                                     sc->me_per_sector) * sc->me_per_sector];
 1737 
 1738                                 /* Commit sector with map entry to storage */
 1739                                 cb->bio_to = sc->components[0].gcons->provider;
 1740                                 cb->bio_done = g_virstor_done;
 1741                                 cb->bio_offset = s_offset;
 1742                                 cb->bio_data = (char *)data_me;
 1743                                 cb->bio_length = sc->sectorsize;
 1744                                 cb->bio_caller1 = &sc->components[0];
 1745                                 bioq_disksort(&bq, cb);
 1746                         }
 1747 
 1748                         comp = &sc->components[me->provider_no];
 1749                         cb = g_clone_bio(b);
 1750                         if (cb == NULL) {
 1751                                 bioq_dismantle(&bq);
 1752                                 if (b->bio_error == 0)
 1753                                         b->bio_error = ENOMEM;
 1754                                 g_io_deliver(b, b->bio_error);
 1755                                 return;
 1756                         }
 1757                         /* Finally, handle the data */
 1758                         cb->bio_to = comp->gcons->provider;
 1759                         cb->bio_done = g_virstor_done;
 1760                         cb->bio_offset = (off_t)me->provider_chunk*(off_t)chunk_size +
 1761                             in_chunk_offset;
 1762                         cb->bio_length = in_chunk_length;
 1763                         cb->bio_data = addr;
 1764                         cb->bio_caller1 = comp;
 1765                         bioq_disksort(&bq, cb);
 1766                 }
 1767                 addr += in_chunk_length;
 1768                 length -= in_chunk_length;
 1769                 offset += in_chunk_length;
 1770         }
 1771 
 1772         /* Fire off bio's here */
 1773         count = 0;
 1774         for (cb = bioq_first(&bq); cb != NULL; cb = bioq_first(&bq)) {
 1775                 bioq_remove(&bq, cb);
 1776                 LOG_REQ(LVL_MOREDEBUG, cb, "Firing request");
 1777                 comp = cb->bio_caller1;
 1778                 cb->bio_caller1 = NULL;
 1779                 LOG_MSG(LVL_DEBUG, " firing bio, offset=%ju, length=%ju",
 1780                     cb->bio_offset, cb->bio_length);
 1781                 g_io_request(cb, comp->gcons);
 1782                 count++;
 1783         }
 1784         if (count == 0) { /* We handled everything locally */
 1785                 b->bio_completed = b->bio_length;
 1786                 g_io_deliver(b, 0);
 1787         }
 1788 
 1789 }
 1790 
 1791 /*
 1792  * Allocate a chunk from a physical provider. Returns physical component,
 1793  * chunk index relative to the component and the component's index.
 1794  */
 1795 static int
 1796 allocate_chunk(struct g_virstor_softc *sc, struct g_virstor_component **comp,
 1797     u_int *comp_no_p, u_int *chunk)
 1798 {
 1799         u_int comp_no;
 1800 
 1801         KASSERT(sc->curr_component < sc->n_components,
 1802             ("%s: Invalid curr_component: %u",  __func__, sc->curr_component));
 1803 
 1804         comp_no = sc->curr_component;
 1805         *comp = &sc->components[comp_no];
 1806         dump_component(*comp);
 1807         if ((*comp)->chunk_next >= (*comp)->chunk_count) {
 1808                 /* This component is full. Allocate next component */
 1809                 if (comp_no >= sc->n_components-1) {
 1810                         LOG_MSG(LVL_ERROR, "All physical space allocated for %s",
 1811                             sc->geom->name);
 1812                         return (-1);
 1813                 }
 1814                 (*comp)->flags &= ~VIRSTOR_PROVIDER_CURRENT;
 1815                 sc->curr_component = ++comp_no;
 1816 
 1817                 *comp = &sc->components[comp_no];
 1818                 if (comp_no >= sc->n_components - g_virstor_component_watermark-1)
 1819                         LOG_MSG(LVL_WARNING, "Device %s running out of components "
 1820                             "(switching to %u/%u: %s)", sc->geom->name,
 1821                             comp_no+1, sc->n_components,
 1822                             (*comp)->gcons->provider->name);
 1823                 /* Take care not to overwrite reserved chunks */
 1824                 if ( (*comp)->chunk_reserved > 0 &&
 1825                     (*comp)->chunk_next < (*comp)->chunk_reserved)
 1826                         (*comp)->chunk_next = (*comp)->chunk_reserved;
 1827 
 1828                 (*comp)->flags |=
 1829                     VIRSTOR_PROVIDER_ALLOCATED | VIRSTOR_PROVIDER_CURRENT;
 1830                 dump_component(*comp);
 1831                 *comp_no_p = comp_no;
 1832                 *chunk = (*comp)->chunk_next++;
 1833         } else {
 1834                 *comp_no_p = comp_no;
 1835                 *chunk = (*comp)->chunk_next++;
 1836         }
 1837         return (0);
 1838 }
 1839 
 1840 /* Dump a component */
 1841 static void
 1842 dump_component(struct g_virstor_component *comp)
 1843 {
 1844 
 1845         if (g_virstor_debug < LVL_DEBUG2)
 1846                 return;
 1847         printf("Component %d: %s\n", comp->index, comp->gcons->provider->name);
 1848         printf("  chunk_count: %u\n", comp->chunk_count);
 1849         printf("   chunk_next: %u\n", comp->chunk_next);
 1850         printf("        flags: %u\n", comp->flags);
 1851 }
 1852 
 1853 #if 0
 1854 /* Dump a map entry */
 1855 static void
 1856 dump_me(struct virstor_map_entry *me, unsigned int nr)
 1857 {
 1858         if (g_virstor_debug < LVL_DEBUG)
 1859                 return;
 1860         printf("VIRT. CHUNK #%d: ", nr);
 1861         if ((me->flags & VIRSTOR_MAP_ALLOCATED) == 0)
 1862                 printf("(unallocated)\n");
 1863         else
 1864                 printf("allocated at provider %u, provider_chunk %u\n",
 1865                     me->provider_no, me->provider_chunk);
 1866 }
 1867 #endif
 1868 
 1869 /*
 1870  * Dismantle bio_queue and destroy its components
 1871  */
 1872 static void
 1873 bioq_dismantle(struct bio_queue_head *bq)
 1874 {
 1875         struct bio *b;
 1876 
 1877         for (b = bioq_first(bq); b != NULL; b = bioq_first(bq)) {
 1878                 bioq_remove(bq, b);
 1879                 g_destroy_bio(b);
 1880         }
 1881 }
 1882 
 1883 /*
 1884  * The function that shouldn't be called.
 1885  * When this is called, the stack is already garbled because of
 1886  * argument mismatch. There's nothing to do now but panic, which is
 1887  * accidentally the whole purpose of this function.
 1888  * Motivation: to guard from accidentally calling geom methods when
 1889  * they shouldn't be called. (see g_..._taste)
 1890  */
 1891 static void
 1892 invalid_call(void)
 1893 {
 1894         panic("invalid_call() has just been called. Something's fishy here.");
 1895 }
 1896 
 1897 DECLARE_GEOM_CLASS(g_virstor_class, g_virstor); /* Let there be light */

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