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