module/zfs/spa_config.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  24  * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
  25  * Copyright (c) 2013 by Delphix. All rights reserved.
  26  */
  27
  28 #include <sys/spa.h>
  29 #include <sys/spa_impl.h>
  30 #include <sys/nvpair.h>
  31 #include <sys/uio.h>
  32 #include <sys/fs/zfs.h>
  33 #include <sys/vdev_impl.h>
  34 #include <sys/zfs_ioctl.h>
  35 #include <sys/systeminfo.h>
  36 #include <sys/sunddi.h>
  37 #include <sys/zfeature.h>
  38 #ifdef _KERNEL
  39 #include <sys/kobj.h>
  40 #include <sys/zone.h>
  41 #endif
  42
  43 /*
  44  * Pool configuration repository.
  45  *
  46  * Pool configuration is stored as a packed nvlist on the filesystem.  By
  47  * default, all pools are stored in /etc/zfs/zpool.cache and loaded on boot
  48  * (when the ZFS module is loaded).  Pools can also have the 'cachefile'
  49  * property set that allows them to be stored in an alternate location until
  50  * the control of external software.
  51  *
  52  * For each cache file, we have a single nvlist which holds all the
  53  * configuration information.  When the module loads, we read this information
  54  * from /etc/zfs/zpool.cache and populate the SPA namespace.  This namespace is
  55  * maintained independently in spa.c.  Whenever the namespace is modified, or
  56  * the configuration of a pool is changed, we call spa_config_sync(), which
  57  * walks through all the active pools and writes the configuration to disk.
  58  */
  59
  60 static uint64_t spa_config_generation = 1;
  61
  62 /*
  63  * This can be overridden in userland to preserve an alternate namespace for
  64  * userland pools when doing testing.
  65  */
  66 char *spa_config_path = ZPOOL_CACHE;
  67 int zfs_autoimport_disable = 0;
  68
  69 /*
  70  * Called when the module is first loaded, this routine loads the configuration
  71  * file into the SPA namespace.  It does not actually open or load the pools; it
  72  * only populates the namespace.
  73  */
  74 void
  75 spa_config_load(void)
  76 {
  77         void *buf = NULL;
  78         nvlist_t *nvlist, *child;
  79         nvpair_t *nvpair;
  80         char *pathname;
  81         struct _buf *file;
  82         uint64_t fsize;
  83
  84         if (zfs_autoimport_disable)
  85                 return;
  86
  87         /*
  88          * Open the configuration file.
  89          */
  90         pathname = kmem_alloc(MAXPATHLEN, KM_SLEEP);
  91
  92         (void) snprintf(pathname, MAXPATHLEN, "%s%s",
  93             (rootdir != NULL) ? "./" : "", spa_config_path);
  94
  95         file = kobj_open_file(pathname);
  96
  97         kmem_free(pathname, MAXPATHLEN);
  98
  99         if (file == (struct _buf *)-1)
 100                 return;
 101
 102         if (kobj_get_filesize(file, &fsize) != 0)
 103                 goto out;
 104
 105         buf = kmem_alloc(fsize, KM_SLEEP);
 106
 107         /*
 108          * Read the nvlist from the file.
 109          */
 110         if (kobj_read_file(file, buf, fsize, 0) < 0)
 111                 goto out;
 112
 113         /*
 114          * Unpack the nvlist.
 115          */
 116         if (nvlist_unpack(buf, fsize, &nvlist, KM_SLEEP) != 0)
 117                 goto out;
 118
 119         /*
 120          * Iterate over all elements in the nvlist, creating a new spa_t for
 121          * each one with the specified configuration.
 122          */
 123         mutex_enter(&spa_namespace_lock);
 124         nvpair = NULL;
 125         while ((nvpair = nvlist_next_nvpair(nvlist, nvpair)) != NULL) {
 126                 if (nvpair_type(nvpair) != DATA_TYPE_NVLIST)
 127                         continue;
 128
 129                 VERIFY(nvpair_value_nvlist(nvpair, &child) == 0);
 130
 131                 if (spa_lookup(nvpair_name(nvpair)) != NULL)
 132                         continue;
 133                 (void) spa_add(nvpair_name(nvpair), child, NULL);
 134         }
 135         mutex_exit(&spa_namespace_lock);
 136
 137         nvlist_free(nvlist);
 138
 139 out:
 140         if (buf != NULL)
 141                 kmem_free(buf, fsize);
 142
 143         kobj_close_file(file);
 144 }
 145
 146 static void
 147 spa_config_write(spa_config_dirent_t *dp, nvlist_t *nvl)
 148 {
 149         size_t buflen;
 150         char *buf;
 151         vnode_t *vp;
 152         int oflags = FWRITE | FTRUNC | FCREAT | FOFFMAX;
 153         char *temp;
 154
 155         /*
 156          * If the nvlist is empty (NULL), then remove the old cachefile.
 157          */
 158         if (nvl == NULL) {
 159                 (void) vn_remove(dp->scd_path, UIO_SYSSPACE, RMFILE);
 160                 return;
 161         }
 162
 163         /*
 164          * Pack the configuration into a buffer.
 165          */
 166         VERIFY(nvlist_size(nvl, &buflen, NV_ENCODE_XDR) == 0);
 167
 168         buf = kmem_alloc(buflen, KM_SLEEP);
 169         temp = kmem_zalloc(MAXPATHLEN, KM_SLEEP);
 170
 171         VERIFY(nvlist_pack(nvl, &buf, &buflen, NV_ENCODE_XDR,
 172             KM_SLEEP) == 0);
 173
 174         /*
 175          * Write the configuration to disk.  We need to do the traditional
 176          * 'write to temporary file, sync, move over original' to make sure we
 177          * always have a consistent view of the data.
 178          */
 179         (void) snprintf(temp, MAXPATHLEN, "%s.tmp", dp->scd_path);
 180
 181         if (vn_open(temp, UIO_SYSSPACE, oflags, 0644, &vp, CRCREAT, 0) == 0) {
 182                 if (vn_rdwr(UIO_WRITE, vp, buf, buflen, 0, UIO_SYSSPACE,
 183                     0, RLIM64_INFINITY, kcred, NULL) == 0 &&
 184                     VOP_FSYNC(vp, FSYNC, kcred, NULL) == 0) {
 185                         (void) vn_rename(temp, dp->scd_path, UIO_SYSSPACE);
 186                 }
 187                 (void) VOP_CLOSE(vp, oflags, 1, 0, kcred, NULL);
 188         }
 189
 190         (void) vn_remove(temp, UIO_SYSSPACE, RMFILE);
 191
 192         kmem_free(buf, buflen);
 193         kmem_free(temp, MAXPATHLEN);
 194 }
 195
 196 /*
 197  * Synchronize pool configuration to disk.  This must be called with the
 198  * namespace lock held. Synchronizing the pool cache is typically done after
 199  * the configuration has been synced to the MOS. This exposes a window where
 200  * the MOS config will have been updated but the cache file has not. If
 201  * the system were to crash at that instant then the cached config may not
 202  * contain the correct information to open the pool and an explicity import
 203  * would be required.
 204  */
 205 void
 206 spa_config_sync(spa_t *target, boolean_t removing, boolean_t postsysevent)
 207 {
 208         spa_config_dirent_t *dp, *tdp;
 209         nvlist_t *nvl;
 210         char *pool_name;
 211
 212         ASSERT(MUTEX_HELD(&spa_namespace_lock));
 213
 214         if (rootdir == NULL || !(spa_mode_global & FWRITE))
 215                 return;
 216
 217         /*
 218          * Iterate over all cachefiles for the pool, past or present.  When the
 219          * cachefile is changed, the new one is pushed onto this list, allowing
 220          * us to update previous cachefiles that no longer contain this pool.
 221          */
 222         for (dp = list_head(&target->spa_config_list); dp != NULL;
 223             dp = list_next(&target->spa_config_list, dp)) {
 224                 spa_t *spa = NULL;
 225                 if (dp->scd_path == NULL)
 226                         continue;
 227
 228                 /*
 229                  * Iterate over all pools, adding any matching pools to 'nvl'.
 230                  */
 231                 nvl = NULL;
 232                 while ((spa = spa_next(spa)) != NULL) {
 233                         /*
 234                          * Skip over our own pool if we're about to remove
 235                          * ourselves from the spa namespace or any pool that
 236                          * is readonly. Since we cannot guarantee that a
 237                          * readonly pool would successfully import upon reboot,
 238                          * we don't allow them to be written to the cache file.
 239                          */
 240                         if ((spa == target && removing) ||
 241                             !spa_writeable(spa))
 242                                 continue;
 243
 244                         mutex_enter(&spa->spa_props_lock);
 245                         tdp = list_head(&spa->spa_config_list);
 246                         if (spa->spa_config == NULL ||
 247                             tdp->scd_path == NULL ||
 248                             strcmp(tdp->scd_path, dp->scd_path) != 0) {
 249                                 mutex_exit(&spa->spa_props_lock);
 250                                 continue;
 251                         }
 252
 253                         if (nvl == NULL)
 254                                 VERIFY(nvlist_alloc(&nvl, NV_UNIQUE_NAME,
 255                                     KM_SLEEP) == 0);
 256
 257                         if (spa->spa_import_flags & ZFS_IMPORT_TEMP_NAME) {
 258                                 VERIFY0(nvlist_lookup_string(spa->spa_config,
 259                                         ZPOOL_CONFIG_POOL_NAME, &pool_name));
 260                         } else
 261                                 pool_name = spa_name(spa);
 262
 263                         VERIFY(nvlist_add_nvlist(nvl, pool_name,
 264                             spa->spa_config) == 0);
 265                         mutex_exit(&spa->spa_props_lock);
 266                 }
 267
 268                 spa_config_write(dp, nvl);
 269                 nvlist_free(nvl);
 270         }
 271
 272         /*
 273          * Remove any config entries older than the current one.
 274          */
 275         dp = list_head(&target->spa_config_list);
 276         while ((tdp = list_next(&target->spa_config_list, dp)) != NULL) {
 277                 list_remove(&target->spa_config_list, tdp);
 278                 if (tdp->scd_path != NULL)
 279                         spa_strfree(tdp->scd_path);
 280                 kmem_free(tdp, sizeof (spa_config_dirent_t));
 281         }
 282
 283         spa_config_generation++;
 284
 285         if (postsysevent)
 286                 spa_event_notify(target, NULL, FM_EREPORT_ZFS_CONFIG_SYNC);
 287 }
 288
 289 /*
 290  * Sigh.  Inside a local zone, we don't have access to /etc/zfs/zpool.cache,
 291  * and we don't want to allow the local zone to see all the pools anyway.
 292  * So we have to invent the ZFS_IOC_CONFIG ioctl to grab the configuration
 293  * information for all pool visible within the zone.
 294  */
 295 nvlist_t *
 296 spa_all_configs(uint64_t *generation)
 297 {
 298         nvlist_t *pools;
 299         spa_t *spa = NULL;
 300
 301         if (*generation == spa_config_generation)
 302                 return (NULL);
 303
 304         VERIFY(nvlist_alloc(&pools, NV_UNIQUE_NAME, KM_SLEEP) == 0);
 305
 306         mutex_enter(&spa_namespace_lock);
 307         while ((spa = spa_next(spa)) != NULL) {
 308                 if (INGLOBALZONE(curproc) ||
 309                     zone_dataset_visible(spa_name(spa), NULL)) {
 310                         mutex_enter(&spa->spa_props_lock);
 311                         VERIFY(nvlist_add_nvlist(pools, spa_name(spa),
 312                             spa->spa_config) == 0);
 313                         mutex_exit(&spa->spa_props_lock);
 314                 }
 315         }
 316         *generation = spa_config_generation;
 317         mutex_exit(&spa_namespace_lock);
 318
 319         return (pools);
 320 }
 321
 322 void
 323 spa_config_set(spa_t *spa, nvlist_t *config)
 324 {
 325         mutex_enter(&spa->spa_props_lock);
 326         if (spa->spa_config != NULL)
 327                 nvlist_free(spa->spa_config);
 328         spa->spa_config = config;
 329         mutex_exit(&spa->spa_props_lock);
 330 }
 331
 332 /*
 333  * Generate the pool's configuration based on the current in-core state.
 334  *
 335  * We infer whether to generate a complete config or just one top-level config
 336  * based on whether vd is the root vdev.
 337  */
 338 nvlist_t *
 339 spa_config_generate(spa_t *spa, vdev_t *vd, uint64_t txg, int getstats)
 340 {
 341         nvlist_t *config, *nvroot;
 342         vdev_t *rvd = spa->spa_root_vdev;
 343         unsigned long hostid = 0;
 344         boolean_t locked = B_FALSE;
 345         uint64_t split_guid;
 346         char *pool_name;
 347
 348         if (vd == NULL) {
 349                 vd = rvd;
 350                 locked = B_TRUE;
 351                 spa_config_enter(spa, SCL_CONFIG | SCL_STATE, FTAG, RW_READER);
 352         }
 353
 354         ASSERT(spa_config_held(spa, SCL_CONFIG | SCL_STATE, RW_READER) ==
 355             (SCL_CONFIG | SCL_STATE));
 356
 357         /*
 358          * If txg is -1, report the current value of spa->spa_config_txg.
 359          */
 360         if (txg == -1ULL)
 361                 txg = spa->spa_config_txg;
 362
 363         /*
 364          * Originally, users had to handle spa namespace collisions by either
 365          * exporting the already imported pool or by specifying a new name for
 366          * the pool with a conflicting name. In the case of root pools from
 367          * virtual guests, neither approach to collision resolution is
 368          * reasonable. This is addressed by extending the new name syntax with
 369          * an option to specify that the new name is temporary. When specified,
 370          * ZFS_IMPORT_TEMP_NAME will be set in spa->spa_import_flags to tell us
 371          * to use the previous name, which we do below.
 372          */
 373         if (spa->spa_import_flags & ZFS_IMPORT_TEMP_NAME) {
 374                 VERIFY0(nvlist_lookup_string(spa->spa_config,
 375                         ZPOOL_CONFIG_POOL_NAME, &pool_name));
 376         } else
 377                 pool_name = spa_name(spa);
 378
 379         VERIFY(nvlist_alloc(&config, NV_UNIQUE_NAME, KM_SLEEP) == 0);
 380
 381         VERIFY(nvlist_add_uint64(config, ZPOOL_CONFIG_VERSION,
 382             spa_version(spa)) == 0);
 383         VERIFY(nvlist_add_string(config, ZPOOL_CONFIG_POOL_NAME,
 384             pool_name) == 0);
 385         VERIFY(nvlist_add_uint64(config, ZPOOL_CONFIG_POOL_STATE,
 386             spa_state(spa)) == 0);
 387         VERIFY(nvlist_add_uint64(config, ZPOOL_CONFIG_POOL_TXG,
 388             txg) == 0);
 389         VERIFY(nvlist_add_uint64(config, ZPOOL_CONFIG_POOL_GUID,
 390             spa_guid(spa)) == 0);
 391         VERIFY(nvlist_add_uint64(config, ZPOOL_CONFIG_ERRATA,
 392             spa->spa_errata) == 0);
 393         VERIFY(spa->spa_comment == NULL || nvlist_add_string(config,
 394             ZPOOL_CONFIG_COMMENT, spa->spa_comment) == 0);
 395
 396
 397 #ifdef  _KERNEL
 398         hostid = zone_get_hostid(NULL);
 399 #else   /* _KERNEL */
 400         /*
 401          * We're emulating the system's hostid in userland, so we can't use
 402          * zone_get_hostid().
 403          */
 404         (void) ddi_strtoul(hw_serial, NULL, 10, &hostid);
 405 #endif  /* _KERNEL */
 406         if (hostid != 0) {
 407                 VERIFY(nvlist_add_uint64(config, ZPOOL_CONFIG_HOSTID,
 408                     hostid) == 0);
 409         }
 410         VERIFY0(nvlist_add_string(config, ZPOOL_CONFIG_HOSTNAME,
 411             utsname()->nodename));
 412
 413         if (vd != rvd) {
 414                 VERIFY(nvlist_add_uint64(config, ZPOOL_CONFIG_TOP_GUID,
 415                     vd->vdev_top->vdev_guid) == 0);
 416                 VERIFY(nvlist_add_uint64(config, ZPOOL_CONFIG_GUID,
 417                     vd->vdev_guid) == 0);
 418                 if (vd->vdev_isspare)
 419                         VERIFY(nvlist_add_uint64(config, ZPOOL_CONFIG_IS_SPARE,
 420                             1ULL) == 0);
 421                 if (vd->vdev_islog)
 422                         VERIFY(nvlist_add_uint64(config, ZPOOL_CONFIG_IS_LOG,
 423                             1ULL) == 0);
 424                 vd = vd->vdev_top;              /* label contains top config */
 425         } else {
 426                 /*
 427                  * Only add the (potentially large) split information
 428                  * in the mos config, and not in the vdev labels
 429                  */
 430                 if (spa->spa_config_splitting != NULL)
 431                         VERIFY(nvlist_add_nvlist(config, ZPOOL_CONFIG_SPLIT,
 432                             spa->spa_config_splitting) == 0);
 433         }
 434
 435         /*
 436          * Add the top-level config.  We even add this on pools which
 437          * don't support holes in the namespace.
 438          */
 439         vdev_top_config_generate(spa, config);
 440
 441         /*
 442          * If we're splitting, record the original pool's guid.
 443          */
 444         if (spa->spa_config_splitting != NULL &&
 445             nvlist_lookup_uint64(spa->spa_config_splitting,
 446             ZPOOL_CONFIG_SPLIT_GUID, &split_guid) == 0) {
 447                 VERIFY(nvlist_add_uint64(config, ZPOOL_CONFIG_SPLIT_GUID,
 448                     split_guid) == 0);
 449         }
 450
 451         nvroot = vdev_config_generate(spa, vd, getstats, 0);
 452         VERIFY(nvlist_add_nvlist(config, ZPOOL_CONFIG_VDEV_TREE, nvroot) == 0);
 453         nvlist_free(nvroot);
 454
 455         /*
 456          * Store what's necessary for reading the MOS in the label.
 457          */
 458         VERIFY(nvlist_add_nvlist(config, ZPOOL_CONFIG_FEATURES_FOR_READ,
 459             spa->spa_label_features) == 0);
 460
 461         if (getstats && spa_load_state(spa) == SPA_LOAD_NONE) {
 462                 ddt_histogram_t *ddh;
 463                 ddt_stat_t *dds;
 464                 ddt_object_t *ddo;
 465
 466                 ddh = kmem_zalloc(sizeof (ddt_histogram_t), KM_SLEEP);
 467                 ddt_get_dedup_histogram(spa, ddh);
 468                 VERIFY(nvlist_add_uint64_array(config,
 469                     ZPOOL_CONFIG_DDT_HISTOGRAM,
 470                     (uint64_t *)ddh, sizeof (*ddh) / sizeof (uint64_t)) == 0);
 471                 kmem_free(ddh, sizeof (ddt_histogram_t));
 472
 473                 ddo = kmem_zalloc(sizeof (ddt_object_t), KM_SLEEP);
 474                 ddt_get_dedup_object_stats(spa, ddo);
 475                 VERIFY(nvlist_add_uint64_array(config,
 476                     ZPOOL_CONFIG_DDT_OBJ_STATS,
 477                     (uint64_t *)ddo, sizeof (*ddo) / sizeof (uint64_t)) == 0);
 478                 kmem_free(ddo, sizeof (ddt_object_t));
 479
 480                 dds = kmem_zalloc(sizeof (ddt_stat_t), KM_SLEEP);
 481                 ddt_get_dedup_stats(spa, dds);
 482                 VERIFY(nvlist_add_uint64_array(config,
 483                     ZPOOL_CONFIG_DDT_STATS,
 484                     (uint64_t *)dds, sizeof (*dds) / sizeof (uint64_t)) == 0);
 485                 kmem_free(dds, sizeof (ddt_stat_t));
 486         }
 487
 488         if (locked)
 489                 spa_config_exit(spa, SCL_CONFIG | SCL_STATE, FTAG);
 490
 491         return (config);
 492 }
 493
 494 /*
 495  * Update all disk labels, generate a fresh config based on the current
 496  * in-core state, and sync the global config cache (do not sync the config
 497  * cache if this is a booting rootpool).
 498  */
 499 void
 500 spa_config_update(spa_t *spa, int what)
 501 {
 502         vdev_t *rvd = spa->spa_root_vdev;
 503         uint64_t txg;
 504         int c;
 505
 506         ASSERT(MUTEX_HELD(&spa_namespace_lock));
 507
 508         spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
 509         txg = spa_last_synced_txg(spa) + 1;
 510         if (what == SPA_CONFIG_UPDATE_POOL) {
 511                 vdev_config_dirty(rvd);
 512         } else {
 513                 /*
 514                  * If we have top-level vdevs that were added but have
 515                  * not yet been prepared for allocation, do that now.
 516                  * (It's safe now because the config cache is up to date,
 517                  * so it will be able to translate the new DVAs.)
 518                  * See comments in spa_vdev_add() for full details.
 519                  */
 520                 for (c = 0; c < rvd->vdev_children; c++) {
 521                         vdev_t *tvd = rvd->vdev_child[c];
 522                         if (tvd->vdev_ms_array == 0)
 523                                 vdev_metaslab_set_size(tvd);
 524                         vdev_expand(tvd, txg);
 525                 }
 526         }
 527         spa_config_exit(spa, SCL_ALL, FTAG);
 528
 529         /*
 530          * Wait for the mosconfig to be regenerated and synced.
 531          */
 532         txg_wait_synced(spa->spa_dsl_pool, txg);
 533
 534         /*
 535          * Update the global config cache to reflect the new mosconfig.
 536          */
 537         if (!spa->spa_is_root)
 538                 spa_config_sync(spa, B_FALSE, what != SPA_CONFIG_UPDATE_POOL);
 539
 540         if (what == SPA_CONFIG_UPDATE_POOL)
 541                 spa_config_update(spa, SPA_CONFIG_UPDATE_VDEVS);
 542 }
 543
 544 #if defined(_KERNEL) && defined(HAVE_SPL)
 545 EXPORT_SYMBOL(spa_config_sync);
 546 EXPORT_SYMBOL(spa_config_load);
 547 EXPORT_SYMBOL(spa_all_configs);
 548 EXPORT_SYMBOL(spa_config_set);
 549 EXPORT_SYMBOL(spa_config_generate);
 550 EXPORT_SYMBOL(spa_config_update);
 551
 552 module_param(spa_config_path, charp, 0444);
 553 MODULE_PARM_DESC(spa_config_path, "SPA config file (/etc/zfs/zpool.cache)");
 554
 555 module_param(zfs_autoimport_disable, int, 0644);
 556 MODULE_PARM_DESC(zfs_autoimport_disable, "Disable pool import at module load");
 557
 558 #endif