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.
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.
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]
22 * Copyright 2009 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
27 * Routines to manage the on-disk persistent error log.
29 * Each pool stores a log of all logical data errors seen during normal
30 * operation. This is actually the union of two distinct logs: the last log,
31 * and the current log. All errors seen are logged to the current log. When a
32 * scrub completes, the current log becomes the last log, the last log is thrown
33 * out, and the current log is reinitialized. This way, if an error is somehow
34 * corrected, a new scrub will show that that it no longer exists, and will be
35 * deleted from the log when the scrub completes.
37 * The log is stored using a ZAP object whose key is a string form of the
38 * zbookmark tuple (objset, object, level, blkid), and whose contents is an
39 * optional 'objset:object' human-readable string describing the data. When an
40 * error is first logged, this string will be empty, indicating that no name is
41 * known. This prevents us from having to issue a potentially large amount of
42 * I/O to discover the object name during an error path. Instead, we do the
43 * calculation when the data is requested, storing the result so future queries
46 * This log is then shipped into an nvlist where the key is the dataset name and
47 * the value is the object name. Userland is then responsible for uniquifying
48 * this list and displaying it to the user.
51 #include <sys/dmu_tx.h>
53 #include <sys/spa_impl.h>
58 * This is a stripped-down version of strtoull, suitable only for converting
59 * lowercase hexidecimal numbers that don't overflow.
63 _strtonum(const char *str, char **nptr)
69 while ((c = *str) != '\0') {
70 if (c >= '0' && c <= '9')
72 else if (c >= 'a' && c <= 'f')
91 * Convert a bookmark to a string.
94 bookmark_to_name(zbookmark_t *zb, char *buf, size_t len)
96 (void) snprintf(buf, len, "%llx:%llx:%llx:%llx",
97 (u_longlong_t)zb->zb_objset, (u_longlong_t)zb->zb_object,
98 (u_longlong_t)zb->zb_level, (u_longlong_t)zb->zb_blkid);
102 * Convert a string to a bookmark
106 name_to_bookmark(char *buf, zbookmark_t *zb)
108 zb->zb_objset = _strtonum(buf, &buf);
110 zb->zb_object = _strtonum(buf + 1, &buf);
112 zb->zb_level = (int)_strtonum(buf + 1, &buf);
114 zb->zb_blkid = _strtonum(buf + 1, &buf);
115 ASSERT(*buf == '\0');
120 * Log an uncorrectable error to the persistent error log. We add it to the
121 * spa's list of pending errors. The changes are actually synced out to disk
122 * during spa_errlog_sync().
125 spa_log_error(spa_t *spa, zio_t *zio)
127 zbookmark_t *zb = &zio->io_logical->io_bookmark;
128 spa_error_entry_t search;
129 spa_error_entry_t *new;
134 * If we are trying to import a pool, ignore any errors, as we won't be
135 * writing to the pool any time soon.
137 if (spa->spa_load_state == SPA_LOAD_TRYIMPORT)
140 mutex_enter(&spa->spa_errlist_lock);
143 * If we have had a request to rotate the log, log it to the next list
144 * instead of the current one.
146 if (spa->spa_scrub_active || spa->spa_scrub_finished)
147 tree = &spa->spa_errlist_scrub;
149 tree = &spa->spa_errlist_last;
151 search.se_bookmark = *zb;
152 if (avl_find(tree, &search, &where) != NULL) {
153 mutex_exit(&spa->spa_errlist_lock);
157 new = kmem_zalloc(sizeof (spa_error_entry_t), KM_SLEEP);
158 new->se_bookmark = *zb;
159 avl_insert(tree, new, where);
161 mutex_exit(&spa->spa_errlist_lock);
165 * Return the number of errors currently in the error log. This is actually the
166 * sum of both the last log and the current log, since we don't know the union
167 * of these logs until we reach userland.
170 spa_get_errlog_size(spa_t *spa)
172 uint64_t total = 0, count;
174 mutex_enter(&spa->spa_errlog_lock);
175 if (spa->spa_errlog_scrub != 0 &&
176 zap_count(spa->spa_meta_objset, spa->spa_errlog_scrub,
180 if (spa->spa_errlog_last != 0 && !spa->spa_scrub_finished &&
181 zap_count(spa->spa_meta_objset, spa->spa_errlog_last,
184 mutex_exit(&spa->spa_errlog_lock);
186 mutex_enter(&spa->spa_errlist_lock);
187 total += avl_numnodes(&spa->spa_errlist_last);
188 total += avl_numnodes(&spa->spa_errlist_scrub);
189 mutex_exit(&spa->spa_errlist_lock);
196 process_error_log(spa_t *spa, uint64_t obj, void *addr, size_t *count)
205 for (zap_cursor_init(&zc, spa->spa_meta_objset, obj);
206 zap_cursor_retrieve(&zc, &za) == 0;
207 zap_cursor_advance(&zc)) {
210 zap_cursor_fini(&zc);
214 name_to_bookmark(za.za_name, &zb);
216 if (copyout(&zb, (char *)addr +
217 (*count - 1) * sizeof (zbookmark_t),
218 sizeof (zbookmark_t)) != 0)
224 zap_cursor_fini(&zc);
230 process_error_list(avl_tree_t *list, void *addr, size_t *count)
232 spa_error_entry_t *se;
234 for (se = avl_first(list); se != NULL; se = AVL_NEXT(list, se)) {
239 if (copyout(&se->se_bookmark, (char *)addr +
240 (*count - 1) * sizeof (zbookmark_t),
241 sizeof (zbookmark_t)) != 0)
252 * Copy all known errors to userland as an array of bookmarks. This is
253 * actually a union of the on-disk last log and current log, as well as any
254 * pending error requests.
256 * Because the act of reading the on-disk log could cause errors to be
257 * generated, we have two separate locks: one for the error log and one for the
258 * in-core error lists. We only need the error list lock to log and error, so
259 * we grab the error log lock while we read the on-disk logs, and only pick up
260 * the error list lock when we are finished.
263 spa_get_errlog(spa_t *spa, void *uaddr, size_t *count)
268 mutex_enter(&spa->spa_errlog_lock);
270 ret = process_error_log(spa, spa->spa_errlog_scrub, uaddr, count);
272 if (!ret && !spa->spa_scrub_finished)
273 ret = process_error_log(spa, spa->spa_errlog_last, uaddr,
276 mutex_enter(&spa->spa_errlist_lock);
278 ret = process_error_list(&spa->spa_errlist_scrub, uaddr,
281 ret = process_error_list(&spa->spa_errlist_last, uaddr,
283 mutex_exit(&spa->spa_errlist_lock);
285 mutex_exit(&spa->spa_errlog_lock);
292 * Called when a scrub completes. This simply set a bit which tells which AVL
293 * tree to add new errors. spa_errlog_sync() is responsible for actually
294 * syncing the changes to the underlying objects.
297 spa_errlog_rotate(spa_t *spa)
299 mutex_enter(&spa->spa_errlist_lock);
300 spa->spa_scrub_finished = B_TRUE;
301 mutex_exit(&spa->spa_errlist_lock);
305 * Discard any pending errors from the spa_t. Called when unloading a faulted
306 * pool, as the errors encountered during the open cannot be synced to disk.
309 spa_errlog_drain(spa_t *spa)
311 spa_error_entry_t *se;
314 mutex_enter(&spa->spa_errlist_lock);
317 while ((se = avl_destroy_nodes(&spa->spa_errlist_last,
319 kmem_free(se, sizeof (spa_error_entry_t));
321 while ((se = avl_destroy_nodes(&spa->spa_errlist_scrub,
323 kmem_free(se, sizeof (spa_error_entry_t));
325 mutex_exit(&spa->spa_errlist_lock);
329 * Process a list of errors into the current on-disk log.
332 sync_error_list(spa_t *spa, avl_tree_t *t, uint64_t *obj, dmu_tx_t *tx)
334 spa_error_entry_t *se;
338 if (avl_numnodes(t) != 0) {
339 /* create log if necessary */
341 *obj = zap_create(spa->spa_meta_objset,
342 DMU_OT_ERROR_LOG, DMU_OT_NONE,
345 /* add errors to the current log */
346 for (se = avl_first(t); se != NULL; se = AVL_NEXT(t, se)) {
347 char *name = se->se_name ? se->se_name : "";
349 bookmark_to_name(&se->se_bookmark, buf, sizeof (buf));
351 (void) zap_update(spa->spa_meta_objset,
352 *obj, buf, 1, strlen(name) + 1, name, tx);
355 /* purge the error list */
357 while ((se = avl_destroy_nodes(t, &cookie)) != NULL)
358 kmem_free(se, sizeof (spa_error_entry_t));
363 * Sync the error log out to disk. This is a little tricky because the act of
364 * writing the error log requires the spa_errlist_lock. So, we need to lock the
365 * error lists, take a copy of the lists, and then reinitialize them. Then, we
366 * drop the error list lock and take the error log lock, at which point we
367 * do the errlog processing. Then, if we encounter an I/O error during this
368 * process, we can successfully add the error to the list. Note that this will
369 * result in the perpetual recycling of errors, but it is an unlikely situation
370 * and not a performance critical operation.
373 spa_errlog_sync(spa_t *spa, uint64_t txg)
376 avl_tree_t scrub, last;
379 mutex_enter(&spa->spa_errlist_lock);
382 * Bail out early under normal circumstances.
384 if (avl_numnodes(&spa->spa_errlist_scrub) == 0 &&
385 avl_numnodes(&spa->spa_errlist_last) == 0 &&
386 !spa->spa_scrub_finished) {
387 mutex_exit(&spa->spa_errlist_lock);
391 spa_get_errlists(spa, &last, &scrub);
392 scrub_finished = spa->spa_scrub_finished;
393 spa->spa_scrub_finished = B_FALSE;
395 mutex_exit(&spa->spa_errlist_lock);
396 mutex_enter(&spa->spa_errlog_lock);
398 tx = dmu_tx_create_assigned(spa->spa_dsl_pool, txg);
401 * Sync out the current list of errors.
403 sync_error_list(spa, &last, &spa->spa_errlog_last, tx);
406 * Rotate the log if necessary.
408 if (scrub_finished) {
409 if (spa->spa_errlog_last != 0)
410 VERIFY(dmu_object_free(spa->spa_meta_objset,
411 spa->spa_errlog_last, tx) == 0);
412 spa->spa_errlog_last = spa->spa_errlog_scrub;
413 spa->spa_errlog_scrub = 0;
415 sync_error_list(spa, &scrub, &spa->spa_errlog_last, tx);
419 * Sync out any pending scrub errors.
421 sync_error_list(spa, &scrub, &spa->spa_errlog_scrub, tx);
424 * Update the MOS to reflect the new values.
426 (void) zap_update(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
427 DMU_POOL_ERRLOG_LAST, sizeof (uint64_t), 1,
428 &spa->spa_errlog_last, tx);
429 (void) zap_update(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
430 DMU_POOL_ERRLOG_SCRUB, sizeof (uint64_t), 1,
431 &spa->spa_errlog_scrub, tx);
435 mutex_exit(&spa->spa_errlog_lock);