sys/geom/union/g_union.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   3  *
   4  * Copyright (c) 2022 Marshall Kirk McKusick <mckusick@mckusick.com>
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
  16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
  19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  25  * SUCH DAMAGE.
  26  */
  27
  28 #include <sys/param.h>
  29 #include <sys/bio.h>
  30 #include <sys/buf.h>
  31 #include <sys/ctype.h>
  32 #include <sys/kernel.h>
  33 #include <sys/lock.h>
  34 #include <sys/malloc.h>
  35 #include <sys/module.h>
  36 #include <sys/reboot.h>
  37 #include <sys/rwlock.h>
  38 #include <sys/sbuf.h>
  39 #include <sys/sysctl.h>
  40
  41 #include <geom/geom.h>
  42 #include <geom/geom_dbg.h>
  43 #include <geom/union/g_union.h>
  44
  45 SYSCTL_DECL(_kern_geom);
  46 static SYSCTL_NODE(_kern_geom, OID_AUTO, union, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
  47     "GEOM_UNION stuff");
  48 static u_int g_union_debug = 0;
  49 SYSCTL_UINT(_kern_geom_union, OID_AUTO, debug, CTLFLAG_RW, &g_union_debug, 0,
  50     "Debug level");
  51
  52 static void g_union_config(struct gctl_req *req, struct g_class *mp,
  53     const char *verb);
  54 static g_access_t g_union_access;
  55 static g_start_t g_union_start;
  56 static g_dumpconf_t g_union_dumpconf;
  57 static g_orphan_t g_union_orphan;
  58 static int g_union_destroy_geom(struct gctl_req *req, struct g_class *mp,
  59     struct g_geom *gp);
  60 static g_provgone_t g_union_providergone;
  61 static g_resize_t g_union_resize;
  62
  63 struct g_class g_union_class = {
  64         .name = G_UNION_CLASS_NAME,
  65         .version = G_VERSION,
  66         .ctlreq = g_union_config,
  67         .access = g_union_access,
  68         .start = g_union_start,
  69         .dumpconf = g_union_dumpconf,
  70         .orphan = g_union_orphan,
  71         .destroy_geom = g_union_destroy_geom,
  72         .providergone = g_union_providergone,
  73         .resize = g_union_resize,
  74 };
  75
  76 static void g_union_ctl_create(struct gctl_req *req, struct g_class *mp, bool);
  77 static intmax_t g_union_fetcharg(struct gctl_req *req, const char *name);
  78 static bool g_union_verify_nprefix(const char *name);
  79 static void g_union_ctl_destroy(struct gctl_req *req, struct g_class *mp, bool);
  80 static struct g_geom *g_union_find_geom(struct g_class *mp, const char *name);
  81 static void g_union_ctl_reset(struct gctl_req *req, struct g_class *mp, bool);
  82 static void g_union_ctl_revert(struct gctl_req *req, struct g_class *mp, bool);
  83 static void g_union_revert(struct g_union_softc *sc);
  84 static void g_union_doio(struct g_union_wip *wip);
  85 static void g_union_ctl_commit(struct gctl_req *req, struct g_class *mp, bool);
  86 static void g_union_setmap(struct bio *bp, struct g_union_softc *sc);
  87 static bool g_union_getmap(struct bio *bp, struct g_union_softc *sc,
  88         off_t *len2read);
  89 static void g_union_done(struct bio *bp);
  90 static void g_union_kerneldump(struct bio *bp, struct g_union_softc *sc);
  91 static int g_union_dumper(void *, void *, vm_offset_t, off_t, size_t);
  92 static int g_union_destroy(struct gctl_req *req, struct g_geom *gp, bool force);
  93
  94 /*
  95  * Operate on union-specific configuration commands.
  96  */
  97 static void
  98 g_union_config(struct gctl_req *req, struct g_class *mp, const char *verb)
  99 {
 100         uint32_t *version, *verbose;
 101
 102         g_topology_assert();
 103
 104         version = gctl_get_paraml(req, "version", sizeof(*version));
 105         if (version == NULL) {
 106                 gctl_error(req, "No '%s' argument.", "version");
 107                 return;
 108         }
 109         if (*version != G_UNION_VERSION) {
 110                 gctl_error(req, "Userland and kernel parts are out of sync.");
 111                 return;
 112         }
 113         verbose = gctl_get_paraml(req, "verbose", sizeof(*verbose));
 114         if (verbose == NULL) {
 115                 gctl_error(req, "No '%s' argument.", "verbose");
 116                 return;
 117         }
 118         if (strcmp(verb, "create") == 0) {
 119                 g_union_ctl_create(req, mp, *verbose);
 120                 return;
 121         } else if (strcmp(verb, "destroy") == 0) {
 122                 g_union_ctl_destroy(req, mp, *verbose);
 123                 return;
 124         } else if (strcmp(verb, "reset") == 0) {
 125                 g_union_ctl_reset(req, mp, *verbose);
 126                 return;
 127         } else if (strcmp(verb, "revert") == 0) {
 128                 g_union_ctl_revert(req, mp, *verbose);
 129                 return;
 130         } else if (strcmp(verb, "commit") == 0) {
 131                 g_union_ctl_commit(req, mp, *verbose);
 132                 return;
 133         }
 134
 135         gctl_error(req, "Unknown verb.");
 136 }
 137
 138 /*
 139  * Create a union device.
 140  */
 141 static void
 142 g_union_ctl_create(struct gctl_req *req, struct g_class *mp, bool verbose)
 143 {
 144         struct g_provider *upperpp, *lowerpp, *newpp;
 145         struct g_consumer *uppercp, *lowercp;
 146         struct g_union_softc *sc;
 147         struct g_geom_alias *gap;
 148         struct g_geom *gp;
 149         intmax_t offset, secsize, size, needed;
 150         const char *gunionname;
 151         int *nargs, error, i, n;
 152         char name[64];
 153
 154         g_topology_assert();
 155
 156         nargs = gctl_get_paraml(req, "nargs", sizeof(*nargs));
 157         if (nargs == NULL) {
 158                 gctl_error(req, "No '%s' argument.", "nargs");
 159                 return;
 160         }
 161         if (*nargs < 2) {
 162                 gctl_error(req, "Missing device(s).");
 163                 return;
 164         }
 165         if (*nargs > 2) {
 166                 gctl_error(req, "Extra device(s).");
 167                 return;
 168         }
 169
 170         offset = g_union_fetcharg(req, "offset");
 171         size = g_union_fetcharg(req, "size");
 172         secsize = g_union_fetcharg(req, "secsize");
 173         gunionname = gctl_get_asciiparam(req, "gunionname");
 174
 175         upperpp = gctl_get_provider(req, "arg0");
 176         lowerpp = gctl_get_provider(req, "arg1");
 177         if (upperpp == NULL || lowerpp == NULL)
 178                 /* error message provided by gctl_get_provider() */
 179                 return;
 180         /* Create the union */
 181         if (secsize == 0)
 182                 secsize = lowerpp->sectorsize;
 183         else if ((secsize % lowerpp->sectorsize) != 0) {
 184                 gctl_error(req, "Sector size %jd is not a multiple of lower "
 185                     "provider %s's %jd sector size.", (intmax_t)secsize,
 186                     lowerpp->name, (intmax_t)lowerpp->sectorsize);
 187                 return;
 188         }
 189         if (secsize > maxphys) {
 190                 gctl_error(req, "Too big secsize %jd for lower provider %s.",
 191                     (intmax_t)secsize, lowerpp->name);
 192                 return;
 193         }
 194         if (secsize % upperpp->sectorsize != 0) {
 195                 gctl_error(req, "Sector size %jd is not a multiple of upper "
 196                     "provider %s's %jd sector size.", (intmax_t)secsize,
 197                     upperpp->name, (intmax_t)upperpp->sectorsize);
 198                 return;
 199         }
 200         if ((offset % secsize) != 0) {
 201                 gctl_error(req, "Offset %jd is not a multiple of lower "
 202                     "provider %s's %jd sector size.", (intmax_t)offset,
 203                     lowerpp->name, (intmax_t)lowerpp->sectorsize);
 204                 return;
 205         }
 206         if (size == 0)
 207                 size = lowerpp->mediasize - offset;
 208         else
 209                 size -= offset;
 210         if ((size % secsize) != 0) {
 211                 gctl_error(req, "Size %jd is not a multiple of sector size "
 212                     "%jd.", (intmax_t)size, (intmax_t)secsize);
 213                 return;
 214         }
 215         if (offset + size < lowerpp->mediasize) {
 216                 gctl_error(req, "Size %jd is too small for lower provider %s, "
 217                     "needs %jd.", (intmax_t)(offset + size), lowerpp->name,
 218                     lowerpp->mediasize);
 219                 return;
 220         }
 221         if (size > upperpp->mediasize) {
 222                 gctl_error(req, "Upper provider %s size (%jd) is too small, "
 223                     "needs %jd.", upperpp->name, (intmax_t)upperpp->mediasize,
 224                     (intmax_t)size);
 225                 return;
 226         }
 227         if (gunionname != NULL && !g_union_verify_nprefix(gunionname)) {
 228                 gctl_error(req, "Gunion name %s must be alphanumeric.",
 229                     gunionname);
 230                 return;
 231         }
 232         if (gunionname != NULL) {
 233                 n = snprintf(name, sizeof(name), "%s%s", gunionname,
 234                     G_UNION_SUFFIX);
 235         } else {
 236                 n = snprintf(name, sizeof(name), "%s-%s%s", upperpp->name,
 237                     lowerpp->name, G_UNION_SUFFIX);
 238         }
 239         if (n <= 0 || n >= sizeof(name)) {
 240                 gctl_error(req, "Invalid provider name.");
 241                 return;
 242         }
 243         LIST_FOREACH(gp, &mp->geom, geom) {
 244                 if (strcmp(gp->name, name) == 0) {
 245                         gctl_error(req, "Provider %s already exists.", name);
 246                         return;
 247                 }
 248         }
 249         gp = g_new_geomf(mp, "%s", name);
 250         sc = g_malloc(sizeof(*sc), M_WAITOK | M_ZERO);
 251         rw_init(&sc->sc_rwlock, "gunion");
 252         TAILQ_INIT(&sc->sc_wiplist);
 253         sc->sc_offset = offset;
 254         sc->sc_size = size;
 255         sc->sc_sectorsize = secsize;
 256         sc->sc_reads = 0;
 257         sc->sc_writes = 0;
 258         sc->sc_deletes = 0;
 259         sc->sc_getattrs = 0;
 260         sc->sc_flushes = 0;
 261         sc->sc_speedups = 0;
 262         sc->sc_cmd0s = 0;
 263         sc->sc_cmd1s = 0;
 264         sc->sc_cmd2s = 0;
 265         sc->sc_readbytes = 0;
 266         sc->sc_wrotebytes = 0;
 267         sc->sc_writemap_memory = 0;
 268         gp->softc = sc;
 269
 270         newpp = g_new_providerf(gp, "%s", gp->name);
 271         newpp->flags |= G_PF_DIRECT_SEND | G_PF_DIRECT_RECEIVE;
 272         newpp->mediasize = size;
 273         newpp->sectorsize = secsize;
 274         LIST_FOREACH(gap, &upperpp->aliases, ga_next)
 275                 g_provider_add_alias(newpp, "%s%s", gap->ga_alias,
 276                     G_UNION_SUFFIX);
 277         LIST_FOREACH(gap, &lowerpp->aliases, ga_next)
 278                 g_provider_add_alias(newpp, "%s%s", gap->ga_alias,
 279                     G_UNION_SUFFIX);
 280         lowercp = g_new_consumer(gp);
 281         lowercp->flags |= G_CF_DIRECT_SEND | G_CF_DIRECT_RECEIVE;
 282         if ((error = g_attach(lowercp, lowerpp)) != 0) {
 283                 gctl_error(req, "Error %d: cannot attach to provider %s.",
 284                     error, lowerpp->name);
 285                 goto fail1;
 286         }
 287         /* request read and exclusive access for lower */
 288         if ((error = g_access(lowercp, 1, 0, 1)) != 0) {
 289                 gctl_error(req, "Error %d: cannot obtain exclusive access to "
 290                     "%s.\n\tMust be unmounted or mounted read-only.", error,
 291                     lowerpp->name);
 292                 goto fail2;
 293         }
 294         uppercp = g_new_consumer(gp);
 295         uppercp->flags |= G_CF_DIRECT_SEND | G_CF_DIRECT_RECEIVE;
 296         if ((error = g_attach(uppercp, upperpp)) != 0) {
 297                 gctl_error(req, "Error %d: cannot attach to provider %s.",
 298                     error, upperpp->name);
 299                 goto fail3;
 300         }
 301         /* request read, write, and exclusive access for upper */
 302         if ((error = g_access(uppercp, 1, 1, 1)) != 0) {
 303                 gctl_error(req, "Error %d: cannot obtain write access to %s.",
 304                     error, upperpp->name);
 305                 goto fail4;
 306         }
 307         sc->sc_uppercp = uppercp;
 308         sc->sc_lowercp = lowercp;
 309
 310         newpp->flags |= (upperpp->flags & G_PF_ACCEPT_UNMAPPED) &
 311             (lowerpp->flags & G_PF_ACCEPT_UNMAPPED);
 312         g_error_provider(newpp, 0);
 313         /*
 314          * Allocate the map that tracks the sectors that have been written
 315          * to the top layer. We use a 2-level hierarchy as that lets us
 316          * map up to 1 petabyte using allocations of less than 33 Mb
 317          * when using 4K byte sectors (or 268 Mb with 512 byte sectors).
 318          *
 319          * We totally populate the leaf nodes rather than allocating them
 320          * as they are first used because their usage occurs in the
 321          * g_union_start() routine that may be running in the g_down
 322          * thread which cannot sleep.
 323          */
 324         sc->sc_map_size = roundup(size / secsize, BITS_PER_ENTRY);
 325         needed = sc->sc_map_size / BITS_PER_ENTRY;
 326         for (sc->sc_root_size = 1;
 327              sc->sc_root_size * sc->sc_root_size < needed;
 328              sc->sc_root_size++)
 329                 continue;
 330         sc->sc_writemap_root = g_malloc(sc->sc_root_size * sizeof(uint64_t *),
 331             M_WAITOK | M_ZERO);
 332         sc->sc_leaf_size = sc->sc_root_size;
 333         sc->sc_bits_per_leaf = sc->sc_leaf_size * BITS_PER_ENTRY;
 334         sc->sc_leafused = g_malloc(roundup(sc->sc_root_size, BITS_PER_ENTRY),
 335             M_WAITOK | M_ZERO);
 336         for (i = 0; i < sc->sc_root_size; i++)
 337                 sc->sc_writemap_root[i] =
 338                     g_malloc(sc->sc_leaf_size * sizeof(uint64_t),
 339                     M_WAITOK | M_ZERO);
 340         sc->sc_writemap_memory =
 341             (sc->sc_root_size + sc->sc_root_size * sc->sc_leaf_size) *
 342             sizeof(uint64_t) + roundup(sc->sc_root_size, BITS_PER_ENTRY);
 343         if (verbose)
 344                 gctl_error(req, "Device %s created with memory map size %jd.",
 345                     gp->name, (intmax_t)sc->sc_writemap_memory);
 346         G_UNION_DEBUG(1, "Device %s created with memory map size %jd.",
 347             gp->name, (intmax_t)sc->sc_writemap_memory);
 348         return;
 349
 350 fail4:
 351         g_detach(uppercp);
 352 fail3:
 353         g_destroy_consumer(uppercp);
 354         g_access(lowercp, -1, 0, -1);
 355 fail2:
 356         g_detach(lowercp);
 357 fail1:
 358         g_destroy_consumer(lowercp);
 359         g_destroy_provider(newpp);
 360         g_destroy_geom(gp);
 361 }
 362
 363 /*
 364  * Fetch named option and verify that it is positive.
 365  */
 366 static intmax_t
 367 g_union_fetcharg(struct gctl_req *req, const char *name)
 368 {
 369         intmax_t *val;
 370
 371         val = gctl_get_paraml_opt(req, name, sizeof(*val));
 372         if (val == NULL)
 373                 return (0);
 374         if (*val >= 0)
 375                 return (*val);
 376         gctl_error(req, "Invalid '%s': negative value, using default.", name);
 377         return (0);
 378 }
 379
 380 /*
 381  * Verify that a name is alphanumeric.
 382  */
 383 static bool
 384 g_union_verify_nprefix(const char *name)
 385 {
 386         int i;
 387
 388         for (i = 0; i < strlen(name); i++) {
 389                 if (isalpha(name[i]) == 0 && isdigit(name[i]) == 0) {
 390                         return (false);
 391                 }
 392         }
 393         return (true);
 394 }
 395
 396 /*
 397  * Destroy a union device.
 398  */
 399 static void
 400 g_union_ctl_destroy(struct gctl_req *req, struct g_class *mp, bool verbose)
 401 {
 402         int *nargs, *force, error, i;
 403         struct g_geom *gp;
 404         const char *name;
 405         char param[16];
 406
 407         g_topology_assert();
 408
 409         nargs = gctl_get_paraml(req, "nargs", sizeof(*nargs));
 410         if (nargs == NULL) {
 411                 gctl_error(req, "No '%s' argument.", "nargs");
 412                 return;
 413         }
 414         if (*nargs <= 0) {
 415                 gctl_error(req, "Missing device(s).");
 416                 return;
 417         }
 418         force = gctl_get_paraml(req, "force", sizeof(*force));
 419         if (force == NULL) {
 420                 gctl_error(req, "No 'force' argument.");
 421                 return;
 422         }
 423
 424         for (i = 0; i < *nargs; i++) {
 425                 snprintf(param, sizeof(param), "arg%d", i);
 426                 name = gctl_get_asciiparam(req, param);
 427                 if (name == NULL) {
 428                         gctl_msg(req, "No '%s' argument.", param);
 429                         continue;
 430                 }
 431                 if (strncmp(name, _PATH_DEV, strlen(_PATH_DEV)) == 0)
 432                         name += strlen(_PATH_DEV);
 433                 gp = g_union_find_geom(mp, name);
 434                 if (gp == NULL) {
 435                         gctl_msg(req, "Device %s is invalid.", name);
 436                         continue;
 437                 }
 438                 error = g_union_destroy(verbose ? req : NULL, gp, *force);
 439                 if (error != 0)
 440                         gctl_msg(req, "Error %d: cannot destroy device %s.",
 441                             error, gp->name);
 442         }
 443         gctl_post_messages(req);
 444 }
 445
 446 /*
 447  * Find a union geom.
 448  */
 449 static struct g_geom *
 450 g_union_find_geom(struct g_class *mp, const char *name)
 451 {
 452         struct g_geom *gp;
 453
 454         LIST_FOREACH(gp, &mp->geom, geom) {
 455                 if (strcmp(gp->name, name) == 0)
 456                         return (gp);
 457         }
 458         return (NULL);
 459 }
 460
 461 /*
 462  * Zero out all the statistics associated with a union device.
 463  */
 464 static void
 465 g_union_ctl_reset(struct gctl_req *req, struct g_class *mp, bool verbose)
 466 {
 467         struct g_union_softc *sc;
 468         struct g_provider *pp;
 469         struct g_geom *gp;
 470         char param[16];
 471         int i, *nargs;
 472
 473         g_topology_assert();
 474
 475         nargs = gctl_get_paraml(req, "nargs", sizeof(*nargs));
 476         if (nargs == NULL) {
 477                 gctl_error(req, "No '%s' argument.", "nargs");
 478                 return;
 479         }
 480         if (*nargs <= 0) {
 481                 gctl_error(req, "Missing device(s).");
 482                 return;
 483         }
 484
 485         for (i = 0; i < *nargs; i++) {
 486                 snprintf(param, sizeof(param), "arg%d", i);
 487                 pp = gctl_get_provider(req, param);
 488                 if (pp == NULL) {
 489                         gctl_msg(req, "No '%s' argument.", param);
 490                         continue;
 491                 }
 492                 gp = pp->geom;
 493                 if (gp->class != mp) {
 494                         gctl_msg(req, "Provider %s is invalid.",
 495                             pp->name);
 496                         continue;
 497                 }
 498                 sc = gp->softc;
 499                 sc->sc_reads = 0;
 500                 sc->sc_writes = 0;
 501                 sc->sc_deletes = 0;
 502                 sc->sc_getattrs = 0;
 503                 sc->sc_flushes = 0;
 504                 sc->sc_speedups = 0;
 505                 sc->sc_cmd0s = 0;
 506                 sc->sc_cmd1s = 0;
 507                 sc->sc_cmd2s = 0;
 508                 sc->sc_readbytes = 0;
 509                 sc->sc_wrotebytes = 0;
 510                 if (verbose)
 511                         gctl_msg(req, "Device %s has been reset.", pp->name);
 512                 G_UNION_DEBUG(1, "Device %s has been reset.", pp->name);
 513         }
 514         gctl_post_messages(req);
 515 }
 516
 517 /*
 518  * Revert all write requests made to the top layer of the union.
 519  */
 520 static void
 521 g_union_ctl_revert(struct gctl_req *req, struct g_class *mp, bool verbose)
 522 {
 523         struct g_union_softc *sc;
 524         struct g_provider *pp;
 525         struct g_geom *gp;
 526         char param[16];
 527         int i, *nargs;
 528
 529         g_topology_assert();
 530
 531         nargs = gctl_get_paraml(req, "nargs", sizeof(*nargs));
 532         if (nargs == NULL) {
 533                 gctl_error(req, "No '%s' argument.", "nargs");
 534                 return;
 535         }
 536         if (*nargs <= 0) {
 537                 gctl_error(req, "Missing device(s).");
 538                 return;
 539         }
 540
 541         for (i = 0; i < *nargs; i++) {
 542                 snprintf(param, sizeof(param), "arg%d", i);
 543                 pp = gctl_get_provider(req, param);
 544                 if (pp == NULL) {
 545                         gctl_msg(req, "No '%s' argument.", param);
 546                         continue;
 547                 }
 548                 gp = pp->geom;
 549                 if (gp->class != mp) {
 550                         gctl_msg(req, "Provider %s is invalid.", pp->name);
 551                         continue;
 552                 }
 553                 sc = gp->softc;
 554                 if (g_union_get_writelock(sc) != 0) {
 555                         gctl_msg(req, "Revert already in progress for "
 556                             "provider %s.", pp->name);
 557                         continue;
 558                 }
 559                 /*
 560                  * No mount or other use of union is allowed.
 561                  */
 562                 if (pp->acr > 0 || pp->acw > 0 || pp->ace > 0) {
 563                         gctl_msg(req, "Unable to get exclusive access for "
 564                             "reverting of %s;\n\t%s cannot be mounted or "
 565                             "otherwise open during a revert.",
 566                              pp->name, pp->name);
 567                         g_union_rel_writelock(sc);
 568                         continue;
 569                 }
 570                 g_union_revert(sc);
 571                 g_union_rel_writelock(sc);
 572                 if (verbose)
 573                         gctl_msg(req, "Device %s has been reverted.", pp->name);
 574                 G_UNION_DEBUG(1, "Device %s has been reverted.", pp->name);
 575         }
 576         gctl_post_messages(req);
 577 }
 578
 579 /*
 580  * Revert union writes by zero'ing out the writemap.
 581  */
 582 static void
 583 g_union_revert(struct g_union_softc *sc)
 584 {
 585         int i;
 586
 587         G_WLOCK(sc);
 588         for (i = 0; i < sc->sc_root_size; i++)
 589                 memset(sc->sc_writemap_root[i], 0,
 590                     sc->sc_leaf_size * sizeof(uint64_t));
 591         memset(sc->sc_leafused, 0, roundup(sc->sc_root_size, BITS_PER_ENTRY));
 592         G_WUNLOCK(sc);
 593 }
 594
 595 /*
 596  * Commit all the writes made in the top layer to the lower layer.
 597  */
 598 static void
 599 g_union_ctl_commit(struct gctl_req *req, struct g_class *mp, bool verbose)
 600 {
 601         struct g_union_softc *sc;
 602         struct g_provider *pp, *lowerpp;
 603         struct g_consumer *lowercp;
 604         struct g_geom *gp;
 605         struct bio *bp;
 606         char param[16];
 607         off_t len2rd, len2wt, savelen;
 608         int i, error, error1, *nargs, *force, *reboot;
 609
 610         g_topology_assert();
 611
 612         nargs = gctl_get_paraml(req, "nargs", sizeof(*nargs));
 613         if (nargs == NULL) {
 614                 gctl_error(req, "No '%s' argument.", "nargs");
 615                 return;
 616         }
 617         if (*nargs <= 0) {
 618                 gctl_error(req, "Missing device(s).");
 619                 return;
 620         }
 621         force = gctl_get_paraml(req, "force", sizeof(*force));
 622         if (force == NULL) {
 623                 gctl_error(req, "No 'force' argument.");
 624                 return;
 625         }
 626         reboot = gctl_get_paraml(req, "reboot", sizeof(*reboot));
 627         if (reboot == NULL) {
 628                 gctl_error(req, "No 'reboot' argument.");
 629                 return;
 630         }
 631
 632         /* Get a bio buffer to do our I/O */
 633         bp = g_alloc_bio();
 634         bp->bio_data = g_malloc(MAXBSIZE, M_WAITOK);
 635         bp->bio_done = biodone;
 636         for (i = 0; i < *nargs; i++) {
 637                 snprintf(param, sizeof(param), "arg%d", i);
 638                 pp = gctl_get_provider(req, param);
 639                 if (pp == NULL) {
 640                         gctl_msg(req, "No '%s' argument.", param);
 641                         continue;
 642                 }
 643                 gp = pp->geom;
 644                 if (gp->class != mp) {
 645                         gctl_msg(req, "Provider %s is invalid.", pp->name);
 646                         continue;
 647                 }
 648                 sc = gp->softc;
 649                 if (g_union_get_writelock(sc) != 0) {
 650                         gctl_msg(req, "Commit already in progress for "
 651                             "provider %s.", pp->name);
 652                         continue;
 653                 }
 654
 655                 /* upgrade to write access for lower */
 656                 lowercp = sc->sc_lowercp;
 657                 lowerpp = lowercp->provider;
 658                 /*
 659                  * No mount or other use of union is allowed, unless the
 660                  * -f flag is given which allows read-only mount or usage.
 661                  */
 662                 if ((*force == false && pp->acr > 0) || pp->acw > 0 ||
 663                      pp->ace > 0) {
 664                         gctl_msg(req, "Unable to get exclusive access for "
 665                             "writing of %s.\n\tNote that %s cannot be mounted "
 666                             "or otherwise\n\topen during a commit unless the "
 667                             "-f flag is used.", pp->name, pp->name);
 668                         g_union_rel_writelock(sc);
 669                         continue;
 670                 }
 671                 /*
 672                  * No mount or other use of lower media is allowed, unless the
 673                  * -f flag is given which allows read-only mount or usage.
 674                  */
 675                 if ((*force == false && lowerpp->acr > lowercp->acr) ||
 676                      lowerpp->acw > lowercp->acw ||
 677                      lowerpp->ace > lowercp->ace) {
 678                         gctl_msg(req, "provider %s is unable to get "
 679                             "exclusive access to %s\n\tfor writing. Note that "
 680                             "%s cannot be mounted or otherwise open\n\tduring "
 681                             "a commit unless the -f flag is used.", pp->name,
 682                             lowerpp->name, lowerpp->name);
 683                         g_union_rel_writelock(sc);
 684                         continue;
 685                 }
 686                 if ((error = g_access(lowercp, 0, 1, 0)) != 0) {
 687                         gctl_msg(req, "Error %d: provider %s is unable to "
 688                             "access %s for writing.", error, pp->name,
 689                             lowerpp->name);
 690                         g_union_rel_writelock(sc);
 691                         continue;
 692                 }
 693                 g_topology_unlock();
 694                 /* Loop over write map copying across written blocks */
 695                 bp->bio_offset = 0;
 696                 bp->bio_length = sc->sc_map_size * sc->sc_sectorsize;
 697                 G_RLOCK(sc);
 698                 error = 0;
 699                 while (bp->bio_length > 0) {
 700                         if (!g_union_getmap(bp, sc, &len2rd)) {
 701                                 /* not written, so skip */
 702                                 bp->bio_offset += len2rd;
 703                                 bp->bio_length -= len2rd;
 704                                 continue;
 705                         }
 706                         G_RUNLOCK(sc);
 707                         /* need to read then write len2rd sectors */
 708                         for ( ; len2rd > 0; len2rd -= len2wt) {
 709                                 /* limit ourselves to MAXBSIZE size I/Os */
 710                                 len2wt = len2rd;
 711                                 if (len2wt > MAXBSIZE)
 712                                         len2wt = MAXBSIZE;
 713                                 savelen = bp->bio_length;
 714                                 bp->bio_length = len2wt;
 715                                 bp->bio_cmd = BIO_READ;
 716                                 g_io_request(bp, sc->sc_uppercp);
 717                                 if ((error = biowait(bp, "rdunion")) != 0) {
 718                                         gctl_msg(req, "Commit read error %d "
 719                                             "in provider %s, commit aborted.",
 720                                             error, pp->name);
 721                                         goto cleanup;
 722                                 }
 723                                 bp->bio_flags &= ~BIO_DONE;
 724                                 bp->bio_cmd = BIO_WRITE;
 725                                 g_io_request(bp, lowercp);
 726                                 if ((error = biowait(bp, "wtunion")) != 0) {
 727                                         gctl_msg(req, "Commit write error %d "
 728                                             "in provider %s, commit aborted.",
 729                                             error, pp->name);
 730                                         goto cleanup;
 731                                 }
 732                                 bp->bio_flags &= ~BIO_DONE;
 733                                 bp->bio_offset += len2wt;
 734                                 bp->bio_length = savelen - len2wt;
 735                         }
 736                         G_RLOCK(sc);
 737                 }
 738                 G_RUNLOCK(sc);
 739                 /* clear the write map */
 740                 g_union_revert(sc);
 741 cleanup:
 742                 g_topology_lock();
 743                 /* return lower to previous access */
 744                 if ((error1 = g_access(lowercp, 0, -1, 0)) != 0) {
 745                         G_UNION_DEBUG(2, "Error %d: device %s could not reset "
 746                             "access to %s (r=0 w=-1 e=0).", error1, pp->name,
 747                             lowerpp->name);
 748                 }
 749                 g_union_rel_writelock(sc);
 750                 if (error == 0 && verbose)
 751                         gctl_msg(req, "Device %s has been committed.",
 752                             pp->name);
 753                 G_UNION_DEBUG(1, "Device %s has been committed.", pp->name);
 754         }
 755         gctl_post_messages(req);
 756         g_free(bp->bio_data);
 757         g_destroy_bio(bp);
 758         if (*reboot)
 759                 kern_reboot(RB_AUTOBOOT);
 760 }
 761
 762 /*
 763  * Generally allow access unless a commit is in progress.
 764  */
 765 static int
 766 g_union_access(struct g_provider *pp, int r, int w, int e)
 767 {
 768         struct g_union_softc *sc;
 769
 770         sc = pp->geom->softc;
 771         if (sc == NULL) {
 772                 if (r <= 0 && w <= 0 && e <= 0)
 773                         return (0);
 774                 return (ENXIO);
 775         }
 776         r += pp->acr;
 777         w += pp->acw;
 778         e += pp->ace;
 779         if (g_union_get_writelock(sc) != 0) {
 780                 if ((pp->acr + pp->acw + pp->ace) > 0 && (r + w + e) == 0)
 781                         return (0);
 782                 return (EBUSY);
 783         }
 784         g_union_rel_writelock(sc);
 785         return (0);
 786 }
 787
 788 /*
 789  * Initiate an I/O operation on the union device.
 790  */
 791 static void
 792 g_union_start(struct bio *bp)
 793 {
 794         struct g_union_softc *sc;
 795         struct g_union_wip *wip;
 796         struct bio *cbp;
 797
 798         sc = bp->bio_to->geom->softc;
 799         if (bp->bio_cmd == BIO_READ || bp->bio_cmd == BIO_WRITE) {
 800                 wip = g_malloc(sizeof(*wip), M_NOWAIT);
 801                 if (wip == NULL) {
 802                         g_io_deliver(bp, ENOMEM);
 803                         return;
 804                 }
 805                 TAILQ_INIT(&wip->wip_waiting);
 806                 wip->wip_bp = bp;
 807                 wip->wip_sc = sc;
 808                 wip->wip_start = bp->bio_offset + sc->sc_offset;
 809                 wip->wip_end = wip->wip_start + bp->bio_length - 1;
 810                 wip->wip_numios = 1;
 811                 wip->wip_error = 0;
 812                 g_union_doio(wip);
 813                 return;
 814         }
 815
 816         /*
 817          * All commands other than read and write are passed through to
 818          * the upper-level device since it is writable and thus able to
 819          * respond to delete, flush, and speedup requests.
 820          */
 821         cbp = g_clone_bio(bp);
 822         if (cbp == NULL) {
 823                 g_io_deliver(bp, ENOMEM);
 824                 return;
 825         }
 826         cbp->bio_offset = bp->bio_offset + sc->sc_offset;
 827         cbp->bio_done = g_std_done;
 828
 829         switch (cbp->bio_cmd) {
 830         case BIO_DELETE:
 831                 G_UNION_LOGREQ(cbp, "Delete request received.");
 832                 atomic_add_long(&sc->sc_deletes, 1);
 833                 break;
 834         case BIO_GETATTR:
 835                 G_UNION_LOGREQ(cbp, "Getattr request received.");
 836                 atomic_add_long(&sc->sc_getattrs, 1);
 837                 if (strcmp(cbp->bio_attribute, "GEOM::kerneldump") != 0)
 838                         /* forward the GETATTR to the lower-level device */
 839                         break;
 840                 g_union_kerneldump(bp, sc);
 841                 return;
 842         case BIO_FLUSH:
 843                 G_UNION_LOGREQ(cbp, "Flush request received.");
 844                 atomic_add_long(&sc->sc_flushes, 1);
 845                 break;
 846         case BIO_SPEEDUP:
 847                 G_UNION_LOGREQ(cbp, "Speedup request received.");
 848                 atomic_add_long(&sc->sc_speedups, 1);
 849                 break;
 850         case BIO_CMD0:
 851                 G_UNION_LOGREQ(cbp, "Cmd0 request received.");
 852                 atomic_add_long(&sc->sc_cmd0s, 1);
 853                 break;
 854         case BIO_CMD1:
 855                 G_UNION_LOGREQ(cbp, "Cmd1 request received.");
 856                 atomic_add_long(&sc->sc_cmd1s, 1);
 857                 break;
 858         case BIO_CMD2:
 859                 G_UNION_LOGREQ(cbp, "Cmd2 request received.");
 860                 atomic_add_long(&sc->sc_cmd2s, 1);
 861                 break;
 862         default:
 863                 G_UNION_LOGREQ(cbp, "Unknown (%d) request received.",
 864                     cbp->bio_cmd);
 865                 break;
 866         }
 867         g_io_request(cbp, sc->sc_uppercp);
 868 }
 869
 870 /*
 871  * Initiate a read or write operation on the union device.
 872  */
 873 static void
 874 g_union_doio(struct g_union_wip *wip)
 875 {
 876         struct g_union_softc *sc;
 877         struct g_consumer *cp, *firstcp;
 878         struct g_union_wip *activewip;
 879         struct bio *cbp, *firstbp;
 880         off_t rdlen, len2rd, offset;
 881         int iocnt, needstoblock;
 882         char *level;
 883
 884         /*
 885          * To maintain consistency, we cannot allow concurrent reads
 886          * or writes to the same block.
 887          *
 888          * A work-in-progress (wip) structure is allocated for each
 889          * read or write request. All active requests are kept on the
 890          * softc sc_wiplist. As each request arrives, it is checked to
 891          * see if it overlaps any of the active entries. If it does not
 892          * overlap, then it is added to the active list and initiated.
 893          * If it does overlap an active entry, it is added to the
 894          * wip_waiting list for the active entry that it overlaps.
 895          * When an active entry completes, it restarts all the requests
 896          * on its wip_waiting list.
 897          */
 898         sc = wip->wip_sc;
 899         G_WLOCK(sc);
 900         TAILQ_FOREACH(activewip, &sc->sc_wiplist, wip_next) {
 901                 if (wip->wip_end < activewip->wip_start ||
 902                     wip->wip_start > activewip->wip_end)
 903                         continue;
 904                 needstoblock = 1;
 905                 if (wip->wip_bp->bio_cmd == BIO_WRITE)
 906                         if (activewip->wip_bp->bio_cmd == BIO_WRITE)
 907                                 sc->sc_writeblockwrite += 1;
 908                         else
 909                                 sc->sc_readblockwrite += 1;
 910                 else
 911                         if (activewip->wip_bp->bio_cmd == BIO_WRITE)
 912                                 sc->sc_writeblockread += 1;
 913                         else {
 914                                 sc->sc_readcurrentread += 1;
 915                                 needstoblock = 0;
 916                         }
 917                 /* Put request on a waiting list if necessary */
 918                 if (needstoblock) {
 919                         TAILQ_INSERT_TAIL(&activewip->wip_waiting, wip,
 920                             wip_next);
 921                         G_WUNLOCK(sc);
 922                         return;
 923                 }
 924         }
 925         /* Put request on the active list */
 926         TAILQ_INSERT_TAIL(&sc->sc_wiplist, wip, wip_next);
 927
 928         /*
 929          * Process I/O requests that have been cleared to go.
 930          */
 931         cbp = g_clone_bio(wip->wip_bp);
 932         if (cbp == NULL) {
 933                 TAILQ_REMOVE(&sc->sc_wiplist, wip, wip_next);
 934                 G_WUNLOCK(sc);
 935                 KASSERT(TAILQ_FIRST(&wip->wip_waiting) == NULL,
 936                     ("g_union_doio: non-empty work-in-progress waiting queue"));
 937                 g_io_deliver(wip->wip_bp, ENOMEM);
 938                 g_free(wip);
 939                 return;
 940         }
 941         G_WUNLOCK(sc);
 942         cbp->bio_caller1 = wip;
 943         cbp->bio_done = g_union_done;
 944         cbp->bio_offset = wip->wip_start;
 945
 946         /*
 947          * Writes are always done to the top level. The blocks that
 948          * are written are recorded in the bitmap when the I/O completes.
 949          */
 950         if (cbp->bio_cmd == BIO_WRITE) {
 951                 G_UNION_LOGREQ(cbp, "Sending %jd byte write request to upper "
 952                     "level.", cbp->bio_length);
 953                 atomic_add_long(&sc->sc_writes, 1);
 954                 atomic_add_long(&sc->sc_wrotebytes, cbp->bio_length);
 955                 g_io_request(cbp, sc->sc_uppercp);
 956                 return;
 957         }
 958         /*
 959          * The usual read case is that we either read the top layer
 960          * if the block has been previously written or the bottom layer
 961          * if it has not been written. However, it is possible that
 962          * only part of the block has been written, For example we may
 963          * have written a UFS/FFS file fragment comprising several
 964          * sectors out of an 8-sector block.  Here, if the entire
 965          * 8-sector block is read for example by a snapshot needing
 966          * to copy the full block, then we need to read the written
 967          * sectors from the upper level and the unwritten sectors from
 968          * the lower level. We do this by alternately reading from the
 969          * top and bottom layers until we complete the read. We
 970          * simplify for the common case to just do the I/O and return.
 971          */
 972         atomic_add_long(&sc->sc_reads, 1);
 973         atomic_add_long(&sc->sc_readbytes, cbp->bio_length);
 974         rdlen = cbp->bio_length;
 975         offset = 0;
 976         for (iocnt = 0; ; iocnt++) {
 977                 if (g_union_getmap(cbp, sc, &len2rd)) {
 978                         /* read top */
 979                         cp = sc->sc_uppercp;
 980                         level = "upper";
 981                 } else {
 982                         /* read bottom */
 983                         cp = sc->sc_lowercp;
 984                         level = "lower";
 985                 }
 986                 /* Check if only a single read is required */
 987                 if (iocnt == 0 && rdlen == len2rd) {
 988                         G_UNION_LOGREQLVL((cp == sc->sc_uppercp) ?
 989                             3 : 4, cbp, "Sending %jd byte read "
 990                             "request to %s level.", len2rd, level);
 991                         g_io_request(cbp, cp);
 992                         return;
 993                 }
 994                 cbp->bio_length = len2rd;
 995                 if ((cbp->bio_flags & BIO_UNMAPPED) != 0)
 996                         cbp->bio_ma_offset += offset;
 997                 else
 998                         cbp->bio_data += offset;
 999                 offset += len2rd;
1000                 rdlen -= len2rd;
1001                 G_UNION_LOGREQLVL(3, cbp, "Sending %jd byte read "
1002                     "request to %s level.", len2rd, level);
1003                 /*
1004                  * To avoid prematurely notifying our consumer
1005                  * that their I/O has completed, we have to delay
1006                  * issuing our first I/O request until we have
1007                  * issued all the additional I/O requests.
1008                  */
1009                 if (iocnt > 0) {
1010                         atomic_add_long(&wip->wip_numios, 1);
1011                         g_io_request(cbp, cp);
1012                 } else {
1013                         firstbp = cbp;
1014                         firstcp = cp;
1015                 }
1016                 if (rdlen == 0)
1017                         break;
1018                 /* set up for next read */
1019                 cbp = g_clone_bio(wip->wip_bp);
1020                 if (cbp == NULL) {
1021                         wip->wip_error = ENOMEM;
1022                         atomic_add_long(&wip->wip_numios, -1);
1023                         break;
1024                 }
1025                 cbp->bio_caller1 = wip;
1026                 cbp->bio_done = g_union_done;
1027                 cbp->bio_offset += offset;
1028                 cbp->bio_length = rdlen;
1029                 atomic_add_long(&sc->sc_reads, 1);
1030         }
1031         /* We have issued all our I/O, so start the first one */
1032         g_io_request(firstbp, firstcp);
1033         return;
1034 }
1035
1036 /*
1037  * Used when completing a union I/O operation.
1038  */
1039 static void
1040 g_union_done(struct bio *bp)
1041 {
1042         struct g_union_wip *wip, *waitingwip;
1043         struct g_union_softc *sc;
1044
1045         wip = bp->bio_caller1;
1046         if (wip->wip_error != 0 && bp->bio_error == 0)
1047                 bp->bio_error = wip->wip_error;
1048         wip->wip_error = 0;
1049         if (atomic_fetchadd_long(&wip->wip_numios, -1) == 1) {
1050                 sc = wip->wip_sc;
1051                 G_WLOCK(sc);
1052                 if (bp->bio_cmd == BIO_WRITE)
1053                         g_union_setmap(bp, sc);
1054                 TAILQ_REMOVE(&sc->sc_wiplist, wip, wip_next);
1055                 G_WUNLOCK(sc);
1056                 while ((waitingwip = TAILQ_FIRST(&wip->wip_waiting)) != NULL) {
1057                         TAILQ_REMOVE(&wip->wip_waiting, waitingwip, wip_next);
1058                         g_union_doio(waitingwip);
1059                 }
1060                 g_free(wip);
1061         }
1062         g_std_done(bp);
1063 }
1064
1065 /*
1066  * Record blocks that have been written in the map.
1067  */
1068 static void
1069 g_union_setmap(struct bio *bp, struct g_union_softc *sc)
1070 {
1071         size_t root_idx;
1072         uint64_t **leaf;
1073         uint64_t *wordp;
1074         off_t start, numsec;
1075
1076         G_WLOCKOWNED(sc);
1077         KASSERT(bp->bio_offset % sc->sc_sectorsize == 0,
1078             ("g_union_setmap: offset not on sector boundry"));
1079         KASSERT(bp->bio_length % sc->sc_sectorsize == 0,
1080             ("g_union_setmap: length not a multiple of sectors"));
1081         start = bp->bio_offset / sc->sc_sectorsize;
1082         numsec = bp->bio_length / sc->sc_sectorsize;
1083         KASSERT(start + numsec <= sc->sc_map_size,
1084             ("g_union_setmap: block %jd is out of range", start + numsec));
1085         for ( ; numsec > 0; numsec--, start++) {
1086                 root_idx = start / sc->sc_bits_per_leaf;
1087                 leaf = &sc->sc_writemap_root[root_idx];
1088                 wordp = &(*leaf)
1089                     [(start % sc->sc_bits_per_leaf) / BITS_PER_ENTRY];
1090                 *wordp |= 1ULL << (start % BITS_PER_ENTRY);
1091                 sc->sc_leafused[root_idx / BITS_PER_ENTRY] |=
1092                     1ULL << (root_idx % BITS_PER_ENTRY);
1093         }
1094 }
1095
1096 /*
1097  * Check map to determine whether blocks have been written.
1098  *
1099  * Return true if they have been written so should be read from the top
1100  * layer. Return false if they have not been written so should be read
1101  * from the bottom layer. Return in len2read the bytes to be read. See
1102  * the comment above the BIO_READ implementation in g_union_start() for
1103  * an explantion of why len2read may be shorter than the buffer length.
1104  */
1105 static bool
1106 g_union_getmap(struct bio *bp, struct g_union_softc *sc, off_t *len2read)
1107 {
1108         off_t start, numsec, leafresid, bitloc;
1109         bool first, maptype, retval;
1110         uint64_t *leaf, word;
1111         size_t root_idx;
1112
1113         KASSERT(bp->bio_offset % sc->sc_sectorsize == 0,
1114             ("g_union_getmap: offset not on sector boundry"));
1115         KASSERT(bp->bio_length % sc->sc_sectorsize == 0,
1116             ("g_union_getmap: length not a multiple of sectors"));
1117         start = bp->bio_offset / sc->sc_sectorsize;
1118         numsec = bp->bio_length / sc->sc_sectorsize;
1119         G_UNION_DEBUG(4, "g_union_getmap: check %jd sectors starting at %jd\n",
1120             numsec, start);
1121         KASSERT(start + numsec <= sc->sc_map_size,
1122             ("g_union_getmap: block %jd is out of range", start + numsec));
1123                 root_idx = start / sc->sc_bits_per_leaf;
1124         first = true;
1125         maptype = false;
1126         while (numsec > 0) {
1127                 /* Check first if the leaf records any written sectors */
1128                 root_idx = start / sc->sc_bits_per_leaf;
1129                 leafresid = sc->sc_bits_per_leaf -
1130                     (start % sc->sc_bits_per_leaf);
1131                 if (((sc->sc_leafused[root_idx / BITS_PER_ENTRY]) &
1132                     (1ULL << (root_idx % BITS_PER_ENTRY))) == 0) {
1133                         if (first) {
1134                                 maptype = false;
1135                                 first = false;
1136                         }
1137                         if (maptype)
1138                                 break;
1139                         numsec -= leafresid;
1140                         start += leafresid;
1141                         continue;
1142                 }
1143                 /* Check up to a word boundry, then check word by word */
1144                 leaf = sc->sc_writemap_root[root_idx];
1145                 word = leaf[(start % sc->sc_bits_per_leaf) / BITS_PER_ENTRY];
1146                 bitloc = start % BITS_PER_ENTRY;
1147                 if (bitloc == 0 && (word == 0 || word == ~0)) {
1148                         if (first) {
1149                                 if (word == 0)
1150                                         maptype = false;
1151                                 else
1152                                         maptype = true;
1153                                 first = false;
1154                         }
1155                         if ((word == 0 && maptype) ||
1156                             (word == ~0 && !maptype))
1157                                 break;
1158                         numsec -= BITS_PER_ENTRY;
1159                         start += BITS_PER_ENTRY;
1160                         continue;
1161                 }
1162                 for ( ; bitloc < BITS_PER_ENTRY; bitloc ++) {
1163                         retval = (word & (1ULL << bitloc)) != 0;
1164                         if (first) {
1165                                 maptype = retval;
1166                                 first = false;
1167                         }
1168                         if (maptype == retval) {
1169                                 numsec--;
1170                                 start++;
1171                                 continue;
1172                         }
1173                         goto out;
1174                 }
1175         }
1176 out:
1177         if (numsec < 0) {
1178                 start += numsec;
1179                 numsec = 0;
1180         }
1181         *len2read = bp->bio_length - (numsec * sc->sc_sectorsize);
1182         G_UNION_DEBUG(maptype ? 3 : 4,
1183             "g_union_getmap: return maptype %swritten for %jd "
1184             "sectors ending at %jd\n", maptype ? "" : "NOT ",
1185             *len2read / sc->sc_sectorsize, start - 1);
1186         return (maptype);
1187 }
1188
1189 /*
1190  * Fill in details for a BIO_GETATTR request.
1191  */
1192 static void
1193 g_union_kerneldump(struct bio *bp, struct g_union_softc *sc)
1194 {
1195         struct g_kerneldump *gkd;
1196         struct g_geom *gp;
1197         struct g_provider *pp;
1198
1199         gkd = (struct g_kerneldump *)bp->bio_data;
1200         gp = bp->bio_to->geom;
1201         g_trace(G_T_TOPOLOGY, "%s(%s, %jd, %jd)", __func__, gp->name,
1202             (intmax_t)gkd->offset, (intmax_t)gkd->length);
1203
1204         pp = LIST_FIRST(&gp->provider);
1205
1206         gkd->di.dumper = g_union_dumper;
1207         gkd->di.priv = sc;
1208         gkd->di.blocksize = pp->sectorsize;
1209         gkd->di.maxiosize = DFLTPHYS;
1210         gkd->di.mediaoffset = sc->sc_offset + gkd->offset;
1211         if (gkd->offset > sc->sc_size) {
1212                 g_io_deliver(bp, ENODEV);
1213                 return;
1214         }
1215         if (gkd->offset + gkd->length > sc->sc_size)
1216                 gkd->length = sc->sc_size - gkd->offset;
1217         gkd->di.mediasize = gkd->length;
1218         g_io_deliver(bp, 0);
1219 }
1220
1221 /*
1222  * Handler for g_union_kerneldump().
1223  */
1224 static int
1225 g_union_dumper(void *priv, void *virtual, vm_offset_t physical, off_t offset,
1226     size_t length)
1227 {
1228
1229         return (0);
1230 }
1231
1232 /*
1233  * List union statistics.
1234  */
1235 static void
1236 g_union_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp,
1237     struct g_consumer *cp, struct g_provider *pp)
1238 {
1239         struct g_union_softc *sc;
1240
1241         if (pp != NULL || cp != NULL || gp->softc == NULL)
1242                 return;
1243         sc = gp->softc;
1244         sbuf_printf(sb, "%s<Reads>%ju</Reads>\n", indent,
1245             (uintmax_t)sc->sc_reads);
1246         sbuf_printf(sb, "%s<Writes>%ju</Writes>\n", indent,
1247             (uintmax_t)sc->sc_writes);
1248         sbuf_printf(sb, "%s<Deletes>%ju</Deletes>\n", indent,
1249             (uintmax_t)sc->sc_deletes);
1250         sbuf_printf(sb, "%s<Getattrs>%ju</Getattrs>\n", indent,
1251             (uintmax_t)sc->sc_getattrs);
1252         sbuf_printf(sb, "%s<Flushes>%ju</Flushes>\n", indent,
1253             (uintmax_t)sc->sc_flushes);
1254         sbuf_printf(sb, "%s<Speedups>%ju</Speedups>\n", indent,
1255             (uintmax_t)sc->sc_speedups);
1256         sbuf_printf(sb, "%s<Cmd0s>%ju</Cmd0s>\n", indent,
1257             (uintmax_t)sc->sc_cmd0s);
1258         sbuf_printf(sb, "%s<Cmd1s>%ju</Cmd1s>\n", indent,
1259             (uintmax_t)sc->sc_cmd1s);
1260         sbuf_printf(sb, "%s<Cmd2s>%ju</Cmd2s>\n", indent,
1261             (uintmax_t)sc->sc_cmd2s);
1262         sbuf_printf(sb, "%s<ReadCurrentRead>%ju</ReadCurrentRead>\n", indent,
1263             (uintmax_t)sc->sc_readcurrentread);
1264         sbuf_printf(sb, "%s<ReadBlockWrite>%ju</ReadBlockWrite>\n", indent,
1265             (uintmax_t)sc->sc_readblockwrite);
1266         sbuf_printf(sb, "%s<WriteBlockRead>%ju</WriteBlockRead>\n", indent,
1267             (uintmax_t)sc->sc_writeblockread);
1268         sbuf_printf(sb, "%s<WriteBlockWrite>%ju</WriteBlockWrite>\n", indent,
1269             (uintmax_t)sc->sc_writeblockwrite);
1270         sbuf_printf(sb, "%s<ReadBytes>%ju</ReadBytes>\n", indent,
1271             (uintmax_t)sc->sc_readbytes);
1272         sbuf_printf(sb, "%s<WroteBytes>%ju</WroteBytes>\n", indent,
1273             (uintmax_t)sc->sc_wrotebytes);
1274         sbuf_printf(sb, "%s<Offset>%jd</Offset>\n", indent,
1275             (intmax_t)sc->sc_offset);
1276 }
1277
1278 /*
1279  * Clean up an orphaned geom.
1280  */
1281 static void
1282 g_union_orphan(struct g_consumer *cp)
1283 {
1284
1285         g_topology_assert();
1286         g_union_destroy(NULL, cp->geom, true);
1287 }
1288
1289 /*
1290  * Clean up a union geom.
1291  */
1292 static int
1293 g_union_destroy_geom(struct gctl_req *req, struct g_class *mp,
1294     struct g_geom *gp)
1295 {
1296
1297         return (g_union_destroy(NULL, gp, false));
1298 }
1299
1300 /*
1301  * Clean up a union device.
1302  */
1303 static int
1304 g_union_destroy(struct gctl_req *req, struct g_geom *gp, bool force)
1305 {
1306         struct g_union_softc *sc;
1307         struct g_provider *pp;
1308         int error;
1309
1310         g_topology_assert();
1311         sc = gp->softc;
1312         if (sc == NULL)
1313                 return (ENXIO);
1314         pp = LIST_FIRST(&gp->provider);
1315         if ((sc->sc_flags & DOING_COMMIT) != 0 ||
1316             (pp != NULL && (pp->acr != 0 || pp->acw != 0 || pp->ace != 0))) {
1317                 if (force) {
1318                         if (req != NULL)
1319                                 gctl_msg(req, "Device %s is still in use, "
1320                                     "so is being forcibly removed.", pp->name);
1321                         G_UNION_DEBUG(1, "Device %s is still in use, so "
1322                             "is being forcibly removed.", pp->name);
1323                 } else {
1324                         if (req != NULL)
1325                                 gctl_msg(req, "Device %s is still open "
1326                                     "(r=%d w=%d e=%d).", pp->name, pp->acr,
1327                                     pp->acw, pp->ace);
1328                         G_UNION_DEBUG(1, "Device %s is still open "
1329                             "(r=%d w=%d e=%d).", pp->name, pp->acr,
1330                             pp->acw, pp->ace);
1331                         return (EBUSY);
1332                 }
1333         } else {
1334                 if (req != NULL)
1335                         gctl_msg(req, "Device %s removed.", pp->name);
1336                 G_UNION_DEBUG(1, "Device %s removed.", pp->name);
1337         }
1338         /* Close consumers */
1339         if ((error = g_access(sc->sc_lowercp, -1, 0, -1)) != 0)
1340                 G_UNION_DEBUG(2, "Error %d: device %s could not reset access "
1341                     "to %s.", error, pp->name, sc->sc_lowercp->provider->name);
1342         if ((error = g_access(sc->sc_uppercp, -1, -1, -1)) != 0)
1343                 G_UNION_DEBUG(2, "Error %d: device %s could not reset access "
1344                     "to %s.", error, pp->name, sc->sc_uppercp->provider->name);
1345
1346         g_wither_geom(gp, ENXIO);
1347
1348         return (0);
1349 }
1350
1351 /*
1352  * Clean up a union provider.
1353  */
1354 static void
1355 g_union_providergone(struct g_provider *pp)
1356 {
1357         struct g_geom *gp;
1358         struct g_union_softc *sc;
1359         size_t i;
1360
1361         gp = pp->geom;
1362         sc = gp->softc;
1363         gp->softc = NULL;
1364         for (i = 0; i < sc->sc_root_size; i++)
1365                 g_free(sc->sc_writemap_root[i]);
1366         g_free(sc->sc_writemap_root);
1367         g_free(sc->sc_leafused);
1368         rw_destroy(&sc->sc_rwlock);
1369         g_free(sc);
1370 }
1371
1372 /*
1373  * Respond to a resized provider.
1374  */
1375 static void
1376 g_union_resize(struct g_consumer *cp)
1377 {
1378         struct g_union_softc *sc;
1379         struct g_geom *gp;
1380
1381         g_topology_assert();
1382
1383         gp = cp->geom;
1384         sc = gp->softc;
1385
1386         /*
1387          * If size has gotten bigger, ignore it and just keep using
1388          * the space we already had. Otherwise we are done.
1389          */
1390         if (sc->sc_size < cp->provider->mediasize - sc->sc_offset)
1391                 return;
1392         g_union_destroy(NULL, gp, true);
1393 }
1394
1395 DECLARE_GEOM_CLASS(g_union_class, g_union);
1396 MODULE_VERSION(geom_union, 0);