xref: /illumos-gate/usr/src/uts/common/fs/zfs/spa_config.c (revision 04e56356520b98d5a93c496b10f02530bb6647e0)
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) 2011, 2018 by Delphix. All rights reserved.
26  * Copyright 2017 Joyent, Inc.
27  */
28 
29 #include <sys/spa.h>
30 #include <sys/fm/fs/zfs.h>
31 #include <sys/spa_impl.h>
32 #include <sys/nvpair.h>
33 #include <sys/uio.h>
34 #include <sys/fs/zfs.h>
35 #include <sys/vdev_impl.h>
36 #include <sys/zfs_ioctl.h>
37 #include <sys/utsname.h>
38 #include <sys/systeminfo.h>
39 #include <sys/sunddi.h>
40 #include <sys/zfeature.h>
41 #ifdef _KERNEL
42 #include <sys/kobj.h>
43 #include <sys/zone.h>
44 #endif
45 
46 /*
47  * Pool configuration repository.
48  *
49  * Pool configuration is stored as a packed nvlist on the filesystem.  By
50  * default, all pools are stored in /etc/zfs/zpool.cache and loaded on boot
51  * (when the ZFS module is loaded).  Pools can also have the 'cachefile'
52  * property set that allows them to be stored in an alternate location until
53  * the control of external software.
54  *
55  * For each cache file, we have a single nvlist which holds all the
56  * configuration information.  When the module loads, we read this information
57  * from /etc/zfs/zpool.cache and populate the SPA namespace.  This namespace is
58  * maintained independently in spa.c.  Whenever the namespace is modified, or
59  * the configuration of a pool is changed, we call spa_write_cachefile(), which
60  * walks through all the active pools and writes the configuration to disk.
61  */
62 
63 static uint64_t spa_config_generation = 1;
64 
65 /*
66  * This can be overridden in userland to preserve an alternate namespace for
67  * userland pools when doing testing.
68  */
69 const char *spa_config_path = ZPOOL_CACHE;
70 
71 /*
72  * Called when the module is first loaded, this routine loads the configuration
73  * file into the SPA namespace.  It does not actually open or load the pools; it
74  * only populates the namespace.
75  */
76 void
77 spa_config_load(void)
78 {
79 	void *buf = NULL;
80 	nvlist_t *nvlist, *child;
81 	nvpair_t *nvpair;
82 	char *pathname;
83 	struct _buf *file;
84 	uint64_t fsize;
85 
86 	/*
87 	 * Open the configuration file.
88 	 */
89 	pathname = kmem_alloc(MAXPATHLEN, KM_SLEEP);
90 
91 	(void) snprintf(pathname, MAXPATHLEN, "%s%s",
92 	    (rootdir != NULL) ? "./" : "", spa_config_path);
93 
94 	file = kobj_open_file(pathname);
95 
96 	kmem_free(pathname, MAXPATHLEN);
97 
98 	if (file == (struct _buf *)-1)
99 		return;
100 
101 	if (kobj_get_filesize(file, &fsize) != 0)
102 		goto out;
103 
104 	buf = kmem_alloc(fsize, KM_SLEEP);
105 
106 	/*
107 	 * Read the nvlist from the file.
108 	 */
109 	if (kobj_read_file(file, buf, fsize, 0) < 0)
110 		goto out;
111 
112 	/*
113 	 * Unpack the nvlist.
114 	 */
115 	if (nvlist_unpack(buf, fsize, &nvlist, KM_SLEEP) != 0)
116 		goto out;
117 
118 	/*
119 	 * Iterate over all elements in the nvlist, creating a new spa_t for
120 	 * each one with the specified configuration.
121 	 */
122 	mutex_enter(&spa_namespace_lock);
123 	nvpair = NULL;
124 	while ((nvpair = nvlist_next_nvpair(nvlist, nvpair)) != NULL) {
125 		if (nvpair_type(nvpair) != DATA_TYPE_NVLIST)
126 			continue;
127 
128 		child = fnvpair_value_nvlist(nvpair);
129 
130 		if (spa_lookup(nvpair_name(nvpair)) != NULL)
131 			continue;
132 		(void) spa_add(nvpair_name(nvpair), child, NULL);
133 	}
134 	mutex_exit(&spa_namespace_lock);
135 
136 	nvlist_free(nvlist);
137 
138 out:
139 	if (buf != NULL)
140 		kmem_free(buf, fsize);
141 
142 	kobj_close_file(file);
143 }
144 
145 static int
146 spa_config_write(spa_config_dirent_t *dp, nvlist_t *nvl)
147 {
148 	size_t buflen;
149 	char *buf;
150 	vnode_t *vp;
151 	int oflags = FWRITE | FTRUNC | FCREAT | FOFFMAX;
152 	char *temp;
153 	int err;
154 
155 	/*
156 	 * If the nvlist is empty (NULL), then remove the old cachefile.
157 	 */
158 	if (nvl == NULL) {
159 		err = vn_remove(dp->scd_path, UIO_SYSSPACE, RMFILE);
160 		return (err);
161 	}
162 
163 	/*
164 	 * Pack the configuration into a buffer.
165 	 */
166 	buf = fnvlist_pack(nvl, &buflen);
167 	temp = kmem_zalloc(MAXPATHLEN, KM_SLEEP);
168 
169 	/*
170 	 * Write the configuration to disk.  We need to do the traditional
171 	 * 'write to temporary file, sync, move over original' to make sure we
172 	 * always have a consistent view of the data.
173 	 */
174 	(void) snprintf(temp, MAXPATHLEN, "%s.tmp", dp->scd_path);
175 
176 	err = vn_open(temp, UIO_SYSSPACE, oflags, 0644, &vp, CRCREAT, 0);
177 	if (err == 0) {
178 		err = vn_rdwr(UIO_WRITE, vp, buf, buflen, 0, UIO_SYSSPACE,
179 		    0, RLIM64_INFINITY, kcred, NULL);
180 		if (err == 0)
181 			err = VOP_FSYNC(vp, FSYNC, kcred, NULL);
182 		if (err == 0)
183 			err = vn_rename(temp, dp->scd_path, UIO_SYSSPACE);
184 		(void) VOP_CLOSE(vp, oflags, 1, 0, kcred, NULL);
185 		VN_RELE(vp);
186 	}
187 
188 	(void) vn_remove(temp, UIO_SYSSPACE, RMFILE);
189 
190 	fnvlist_pack_free(buf, buflen);
191 	kmem_free(temp, MAXPATHLEN);
192 	return (err);
193 }
194 
195 /*
196  * Synchronize pool configuration to disk.  This must be called with the
197  * namespace lock held. Synchronizing the pool cache is typically done after
198  * the configuration has been synced to the MOS. This exposes a window where
199  * the MOS config will have been updated but the cache file has not. If
200  * the system were to crash at that instant then the cached config may not
201  * contain the correct information to open the pool and an explicit import
202  * would be required.
203  */
204 void
205 spa_write_cachefile(spa_t *target, boolean_t removing, boolean_t postsysevent)
206 {
207 	spa_config_dirent_t *dp, *tdp;
208 	nvlist_t *nvl;
209 	boolean_t ccw_failure;
210 	int error;
211 	char *pool_name;
212 
213 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
214 
215 	if (rootdir == NULL || !(spa_mode_global & FWRITE))
216 		return;
217 
218 	/*
219 	 * Iterate over all cachefiles for the pool, past or present.  When the
220 	 * cachefile is changed, the new one is pushed onto this list, allowing
221 	 * us to update previous cachefiles that no longer contain this pool.
222 	 */
223 	ccw_failure = B_FALSE;
224 	for (dp = list_head(&target->spa_config_list); dp != NULL;
225 	    dp = list_next(&target->spa_config_list, dp)) {
226 		spa_t *spa = NULL;
227 		if (dp->scd_path == NULL)
228 			continue;
229 
230 		/*
231 		 * Iterate over all pools, adding any matching pools to 'nvl'.
232 		 */
233 		nvl = NULL;
234 		while ((spa = spa_next(spa)) != NULL) {
235 			/*
236 			 * Skip over our own pool if we're about to remove
237 			 * ourselves from the spa namespace or any pool that
238 			 * is readonly. Since we cannot guarantee that a
239 			 * readonly pool would successfully import upon reboot,
240 			 * we don't allow them to be written to the cache file.
241 			 */
242 			if ((spa == target && removing) ||
243 			    !spa_writeable(spa))
244 				continue;
245 
246 			mutex_enter(&spa->spa_props_lock);
247 			tdp = list_head(&spa->spa_config_list);
248 			if (spa->spa_config == NULL ||
249 			    tdp->scd_path == NULL ||
250 			    strcmp(tdp->scd_path, dp->scd_path) != 0) {
251 				mutex_exit(&spa->spa_props_lock);
252 				continue;
253 			}
254 
255 			if (nvl == NULL)
256 				nvl = fnvlist_alloc();
257 
258 			if (spa->spa_import_flags & ZFS_IMPORT_TEMP_NAME) {
259 				pool_name = fnvlist_lookup_string(
260 				    spa->spa_config, ZPOOL_CONFIG_POOL_NAME);
261 			} else {
262 				pool_name = spa_name(spa);
263 			}
264 
265 			fnvlist_add_nvlist(nvl, pool_name,
266 			    spa->spa_config);
267 			mutex_exit(&spa->spa_props_lock);
268 		}
269 
270 		error = spa_config_write(dp, nvl);
271 		if (error != 0)
272 			ccw_failure = B_TRUE;
273 		nvlist_free(nvl);
274 	}
275 
276 	if (ccw_failure) {
277 		/*
278 		 * Keep trying so that configuration data is
279 		 * written if/when any temporary filesystem
280 		 * resource issues are resolved.
281 		 */
282 		if (target->spa_ccw_fail_time == 0) {
283 			zfs_ereport_post(FM_EREPORT_ZFS_CONFIG_CACHE_WRITE,
284 			    target, NULL, NULL, 0, 0);
285 		}
286 		target->spa_ccw_fail_time = gethrtime();
287 		spa_async_request(target, SPA_ASYNC_CONFIG_UPDATE);
288 	} else {
289 		/*
290 		 * Do not rate limit future attempts to update
291 		 * the config cache.
292 		 */
293 		target->spa_ccw_fail_time = 0;
294 	}
295 
296 	/*
297 	 * Remove any config entries older than the current one.
298 	 */
299 	dp = list_head(&target->spa_config_list);
300 	while ((tdp = list_next(&target->spa_config_list, dp)) != NULL) {
301 		list_remove(&target->spa_config_list, tdp);
302 		if (tdp->scd_path != NULL)
303 			spa_strfree(tdp->scd_path);
304 		kmem_free(tdp, sizeof (spa_config_dirent_t));
305 	}
306 
307 	spa_config_generation++;
308 
309 	if (postsysevent)
310 		spa_event_notify(target, NULL, NULL, ESC_ZFS_CONFIG_SYNC);
311 }
312 
313 /*
314  * Sigh.  Inside a local zone, we don't have access to /etc/zfs/zpool.cache,
315  * and we don't want to allow the local zone to see all the pools anyway.
316  * So we have to invent the ZFS_IOC_CONFIG ioctl to grab the configuration
317  * information for all pool visible within the zone.
318  */
319 nvlist_t *
320 spa_all_configs(uint64_t *generation)
321 {
322 	nvlist_t *pools;
323 	spa_t *spa = NULL;
324 
325 	if (*generation == spa_config_generation)
326 		return (NULL);
327 
328 	pools = fnvlist_alloc();
329 
330 	mutex_enter(&spa_namespace_lock);
331 	while ((spa = spa_next(spa)) != NULL) {
332 		if (INGLOBALZONE(curproc) ||
333 		    zone_dataset_visible(spa_name(spa), NULL)) {
334 			mutex_enter(&spa->spa_props_lock);
335 			fnvlist_add_nvlist(pools, spa_name(spa),
336 			    spa->spa_config);
337 			mutex_exit(&spa->spa_props_lock);
338 		}
339 	}
340 	*generation = spa_config_generation;
341 	mutex_exit(&spa_namespace_lock);
342 
343 	return (pools);
344 }
345 
346 void
347 spa_config_set(spa_t *spa, nvlist_t *config)
348 {
349 	mutex_enter(&spa->spa_props_lock);
350 	if (spa->spa_config != NULL && spa->spa_config != config)
351 		nvlist_free(spa->spa_config);
352 	spa->spa_config = config;
353 	mutex_exit(&spa->spa_props_lock);
354 }
355 
356 /*
357  * Generate the pool's configuration based on the current in-core state.
358  *
359  * We infer whether to generate a complete config or just one top-level config
360  * based on whether vd is the root vdev.
361  */
362 nvlist_t *
363 spa_config_generate(spa_t *spa, vdev_t *vd, uint64_t txg, int getstats)
364 {
365 	nvlist_t *config, *nvroot;
366 	vdev_t *rvd = spa->spa_root_vdev;
367 	unsigned long hostid = 0;
368 	boolean_t locked = B_FALSE;
369 	uint64_t split_guid;
370 	char *pool_name;
371 
372 	if (vd == NULL) {
373 		vd = rvd;
374 		locked = B_TRUE;
375 		spa_config_enter(spa, SCL_CONFIG | SCL_STATE, FTAG, RW_READER);
376 	}
377 
378 	ASSERT(spa_config_held(spa, SCL_CONFIG | SCL_STATE, RW_READER) ==
379 	    (SCL_CONFIG | SCL_STATE));
380 
381 	/*
382 	 * If txg is -1, report the current value of spa->spa_config_txg.
383 	 */
384 	if (txg == -1ULL)
385 		txg = spa->spa_config_txg;
386 
387 	/*
388 	 * Originally, users had to handle spa namespace collisions by either
389 	 * exporting the already imported pool or by specifying a new name for
390 	 * the pool with a conflicting name. In the case of root pools from
391 	 * virtual guests, neither approach to collision resolution is
392 	 * reasonable. This is addressed by extending the new name syntax with
393 	 * an option to specify that the new name is temporary. When specified,
394 	 * ZFS_IMPORT_TEMP_NAME will be set in spa->spa_import_flags to tell us
395 	 * to use the previous name, which we do below.
396 	 */
397 	if (spa->spa_import_flags & ZFS_IMPORT_TEMP_NAME) {
398 		pool_name = fnvlist_lookup_string(spa->spa_config,
399 		    ZPOOL_CONFIG_POOL_NAME);
400 	} else {
401 		pool_name = spa_name(spa);
402 	}
403 
404 	config = fnvlist_alloc();
405 
406 	fnvlist_add_uint64(config, ZPOOL_CONFIG_VERSION, spa_version(spa));
407 	fnvlist_add_string(config, ZPOOL_CONFIG_POOL_NAME, pool_name);
408 	fnvlist_add_uint64(config, ZPOOL_CONFIG_POOL_STATE, spa_state(spa));
409 	fnvlist_add_uint64(config, ZPOOL_CONFIG_POOL_TXG, txg);
410 	fnvlist_add_uint64(config, ZPOOL_CONFIG_POOL_GUID, spa_guid(spa));
411 	if (spa->spa_comment != NULL) {
412 		fnvlist_add_string(config, ZPOOL_CONFIG_COMMENT,
413 		    spa->spa_comment);
414 	}
415 
416 	hostid = zone_get_hostid(NULL);
417 
418 	if (hostid != 0) {
419 		fnvlist_add_uint64(config, ZPOOL_CONFIG_HOSTID, hostid);
420 	}
421 	fnvlist_add_string(config, ZPOOL_CONFIG_HOSTNAME, utsname.nodename);
422 
423 	int config_gen_flags = 0;
424 	if (vd != rvd) {
425 		fnvlist_add_uint64(config, ZPOOL_CONFIG_TOP_GUID,
426 		    vd->vdev_top->vdev_guid);
427 		fnvlist_add_uint64(config, ZPOOL_CONFIG_GUID,
428 		    vd->vdev_guid);
429 		if (vd->vdev_isspare) {
430 			fnvlist_add_uint64(config,
431 			    ZPOOL_CONFIG_IS_SPARE, 1ULL);
432 		}
433 		if (vd->vdev_islog) {
434 			fnvlist_add_uint64(config,
435 			    ZPOOL_CONFIG_IS_LOG, 1ULL);
436 		}
437 		vd = vd->vdev_top;		/* label contains top config */
438 	} else {
439 		/*
440 		 * Only add the (potentially large) split information
441 		 * in the mos config, and not in the vdev labels
442 		 */
443 		if (spa->spa_config_splitting != NULL)
444 			fnvlist_add_nvlist(config, ZPOOL_CONFIG_SPLIT,
445 			    spa->spa_config_splitting);
446 		fnvlist_add_boolean(config,
447 		    ZPOOL_CONFIG_HAS_PER_VDEV_ZAPS);
448 
449 		config_gen_flags |= VDEV_CONFIG_MOS;
450 	}
451 
452 	/*
453 	 * Add the top-level config.  We even add this on pools which
454 	 * don't support holes in the namespace.
455 	 */
456 	vdev_top_config_generate(spa, config);
457 
458 	/*
459 	 * If we're splitting, record the original pool's guid.
460 	 */
461 	if (spa->spa_config_splitting != NULL &&
462 	    nvlist_lookup_uint64(spa->spa_config_splitting,
463 	    ZPOOL_CONFIG_SPLIT_GUID, &split_guid) == 0) {
464 		fnvlist_add_uint64(config, ZPOOL_CONFIG_SPLIT_GUID,
465 		    split_guid);
466 	}
467 
468 	nvroot = vdev_config_generate(spa, vd, getstats, config_gen_flags);
469 	fnvlist_add_nvlist(config, ZPOOL_CONFIG_VDEV_TREE, nvroot);
470 	nvlist_free(nvroot);
471 
472 	/*
473 	 * Store what's necessary for reading the MOS in the label.
474 	 */
475 	fnvlist_add_nvlist(config, ZPOOL_CONFIG_FEATURES_FOR_READ,
476 	    spa->spa_label_features);
477 
478 	if (getstats && spa_load_state(spa) == SPA_LOAD_NONE) {
479 		ddt_histogram_t *ddh;
480 		ddt_stat_t *dds;
481 		ddt_object_t *ddo;
482 
483 		ddh = kmem_zalloc(sizeof (ddt_histogram_t), KM_SLEEP);
484 		ddt_get_dedup_histogram(spa, ddh);
485 		fnvlist_add_uint64_array(config,
486 		    ZPOOL_CONFIG_DDT_HISTOGRAM,
487 		    (uint64_t *)ddh, sizeof (*ddh) / sizeof (uint64_t));
488 		kmem_free(ddh, sizeof (ddt_histogram_t));
489 
490 		ddo = kmem_zalloc(sizeof (ddt_object_t), KM_SLEEP);
491 		ddt_get_dedup_object_stats(spa, ddo);
492 		fnvlist_add_uint64_array(config,
493 		    ZPOOL_CONFIG_DDT_OBJ_STATS,
494 		    (uint64_t *)ddo, sizeof (*ddo) / sizeof (uint64_t));
495 		kmem_free(ddo, sizeof (ddt_object_t));
496 
497 		dds = kmem_zalloc(sizeof (ddt_stat_t), KM_SLEEP);
498 		ddt_get_dedup_stats(spa, dds);
499 		fnvlist_add_uint64_array(config,
500 		    ZPOOL_CONFIG_DDT_STATS,
501 		    (uint64_t *)dds, sizeof (*dds) / sizeof (uint64_t));
502 		kmem_free(dds, sizeof (ddt_stat_t));
503 	}
504 
505 	if (locked)
506 		spa_config_exit(spa, SCL_CONFIG | SCL_STATE, FTAG);
507 
508 	return (config);
509 }
510 
511 /*
512  * Update all disk labels, generate a fresh config based on the current
513  * in-core state, and sync the global config cache (do not sync the config
514  * cache if this is a booting rootpool).
515  */
516 void
517 spa_config_update(spa_t *spa, int what)
518 {
519 	vdev_t *rvd = spa->spa_root_vdev;
520 	uint64_t txg;
521 	int c;
522 
523 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
524 
525 	spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
526 	txg = spa_last_synced_txg(spa) + 1;
527 	if (what == SPA_CONFIG_UPDATE_POOL) {
528 		vdev_config_dirty(rvd);
529 	} else {
530 		/*
531 		 * If we have top-level vdevs that were added but have
532 		 * not yet been prepared for allocation, do that now.
533 		 * (It's safe now because the config cache is up to date,
534 		 * so it will be able to translate the new DVAs.)
535 		 * See comments in spa_vdev_add() for full details.
536 		 */
537 		for (c = 0; c < rvd->vdev_children; c++) {
538 			vdev_t *tvd = rvd->vdev_child[c];
539 
540 			/*
541 			 * Explicitly skip vdevs that are indirect or
542 			 * log vdevs that are being removed. The reason
543 			 * is that both of those can have vdev_ms_array
544 			 * set to 0 and we wouldn't want to change their
545 			 * metaslab size nor call vdev_expand() on them.
546 			 */
547 			if (!vdev_is_concrete(tvd) ||
548 			    (tvd->vdev_islog && tvd->vdev_removing))
549 				continue;
550 
551 			if (tvd->vdev_ms_array == 0)
552 				vdev_metaslab_set_size(tvd);
553 			vdev_expand(tvd, txg);
554 		}
555 	}
556 	spa_config_exit(spa, SCL_ALL, FTAG);
557 
558 	/*
559 	 * Wait for the mosconfig to be regenerated and synced.
560 	 */
561 	txg_wait_synced(spa->spa_dsl_pool, txg);
562 
563 	/*
564 	 * Update the global config cache to reflect the new mosconfig.
565 	 */
566 	if (!spa->spa_is_root) {
567 		spa_write_cachefile(spa, B_FALSE,
568 		    what != SPA_CONFIG_UPDATE_POOL);
569 	}
570 
571 	if (what == SPA_CONFIG_UPDATE_POOL)
572 		spa_config_update(spa, SPA_CONFIG_UPDATE_VDEVS);
573 }
574