/* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License (the "License"). * You may not use this file except in compliance with the License. * * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE * or http://www.opensolaris.org/os/licensing. * See the License for the specific language governing permissions * and limitations under the License. * * When distributing Covered Code, include this CDDL HEADER in each * file and include the License file at usr/src/OPENSOLARIS.LICENSE. * If applicable, add the following below this CDDL HEADER, with the * fields enclosed by brackets "[]" replaced with your own identifying * information: Portions Copyright [yyyy] [name of copyright owner] * * CDDL HEADER END */ /* * Copyright (c) 2006, 2010, Oracle and/or its affiliates. All rights reserved. */ /* * Routines to manage the on-disk persistent error log. * * Each pool stores a log of all logical data errors seen during normal * operation. This is actually the union of two distinct logs: the last log, * and the current log. All errors seen are logged to the current log. When a * scrub completes, the current log becomes the last log, the last log is thrown * out, and the current log is reinitialized. This way, if an error is somehow * corrected, a new scrub will show that that it no longer exists, and will be * deleted from the log when the scrub completes. * * The log is stored using a ZAP object whose key is a string form of the * zbookmark tuple (objset, object, level, blkid), and whose contents is an * optional 'objset:object' human-readable string describing the data. When an * error is first logged, this string will be empty, indicating that no name is * known. This prevents us from having to issue a potentially large amount of * I/O to discover the object name during an error path. Instead, we do the * calculation when the data is requested, storing the result so future queries * will be faster. * * This log is then shipped into an nvlist where the key is the dataset name and * the value is the object name. Userland is then responsible for uniquifying * this list and displaying it to the user. */ #include <sys/dmu_tx.h> #include <sys/spa.h> #include <sys/spa_impl.h> #include <sys/zap.h> #include <sys/zio.h> /* * Convert a bookmark to a string. */ static void bookmark_to_name(zbookmark_t *zb, char *buf, size_t len) { (void) snprintf(buf, len, "%llx:%llx:%llx:%llx", (u_longlong_t)zb->zb_objset, (u_longlong_t)zb->zb_object, (u_longlong_t)zb->zb_level, (u_longlong_t)zb->zb_blkid); } /* * Convert a string to a bookmark */ #ifdef _KERNEL static void name_to_bookmark(char *buf, zbookmark_t *zb) { zb->zb_objset = strtonum(buf, &buf); ASSERT(*buf == ':'); zb->zb_object = strtonum(buf + 1, &buf); ASSERT(*buf == ':'); zb->zb_level = (int)strtonum(buf + 1, &buf); ASSERT(*buf == ':'); zb->zb_blkid = strtonum(buf + 1, &buf); ASSERT(*buf == '\0'); } #endif /* * Log an uncorrectable error to the persistent error log. We add it to the * spa's list of pending errors. The changes are actually synced out to disk * during spa_errlog_sync(). */ void spa_log_error(spa_t *spa, zio_t *zio) { zbookmark_t *zb = &zio->io_logical->io_bookmark; spa_error_entry_t search; spa_error_entry_t *new; avl_tree_t *tree; avl_index_t where; /* * If we are trying to import a pool, ignore any errors, as we won't be * writing to the pool any time soon. */ if (spa_load_state(spa) == SPA_LOAD_TRYIMPORT) return; mutex_enter(&spa->spa_errlist_lock); /* * If we have had a request to rotate the log, log it to the next list * instead of the current one. */ if (spa->spa_scrub_active || spa->spa_scrub_finished) tree = &spa->spa_errlist_scrub; else tree = &spa->spa_errlist_last; search.se_bookmark = *zb; if (avl_find(tree, &search, &where) != NULL) { mutex_exit(&spa->spa_errlist_lock); return; } new = kmem_zalloc(sizeof (spa_error_entry_t), KM_SLEEP); new->se_bookmark = *zb; avl_insert(tree, new, where); mutex_exit(&spa->spa_errlist_lock); } /* * Return the number of errors currently in the error log. This is actually the * sum of both the last log and the current log, since we don't know the union * of these logs until we reach userland. */ uint64_t spa_get_errlog_size(spa_t *spa) { uint64_t total = 0, count; mutex_enter(&spa->spa_errlog_lock); if (spa->spa_errlog_scrub != 0 && zap_count(spa->spa_meta_objset, spa->spa_errlog_scrub, &count) == 0) total += count; if (spa->spa_errlog_last != 0 && !spa->spa_scrub_finished && zap_count(spa->spa_meta_objset, spa->spa_errlog_last, &count) == 0) total += count; mutex_exit(&spa->spa_errlog_lock); mutex_enter(&spa->spa_errlist_lock); total += avl_numnodes(&spa->spa_errlist_last); total += avl_numnodes(&spa->spa_errlist_scrub); mutex_exit(&spa->spa_errlist_lock); return (total); } #ifdef _KERNEL static int process_error_log(spa_t *spa, uint64_t obj, void *addr, size_t *count) { zap_cursor_t zc; zap_attribute_t za; zbookmark_t zb; if (obj == 0) return (0); for (zap_cursor_init(&zc, spa->spa_meta_objset, obj); zap_cursor_retrieve(&zc, &za) == 0; zap_cursor_advance(&zc)) { if (*count == 0) { zap_cursor_fini(&zc); return (ENOMEM); } name_to_bookmark(za.za_name, &zb); if (copyout(&zb, (char *)addr + (*count - 1) * sizeof (zbookmark_t), sizeof (zbookmark_t)) != 0) return (EFAULT); *count -= 1; } zap_cursor_fini(&zc); return (0); } static int process_error_list(avl_tree_t *list, void *addr, size_t *count) { spa_error_entry_t *se; for (se = avl_first(list); se != NULL; se = AVL_NEXT(list, se)) { if (*count == 0) return (ENOMEM); if (copyout(&se->se_bookmark, (char *)addr + (*count - 1) * sizeof (zbookmark_t), sizeof (zbookmark_t)) != 0) return (EFAULT); *count -= 1; } return (0); } #endif /* * Copy all known errors to userland as an array of bookmarks. This is * actually a union of the on-disk last log and current log, as well as any * pending error requests. * * Because the act of reading the on-disk log could cause errors to be * generated, we have two separate locks: one for the error log and one for the * in-core error lists. We only need the error list lock to log and error, so * we grab the error log lock while we read the on-disk logs, and only pick up * the error list lock when we are finished. */ int spa_get_errlog(spa_t *spa, void *uaddr, size_t *count) { int ret = 0; #ifdef _KERNEL mutex_enter(&spa->spa_errlog_lock); ret = process_error_log(spa, spa->spa_errlog_scrub, uaddr, count); if (!ret && !spa->spa_scrub_finished) ret = process_error_log(spa, spa->spa_errlog_last, uaddr, count); mutex_enter(&spa->spa_errlist_lock); if (!ret) ret = process_error_list(&spa->spa_errlist_scrub, uaddr, count); if (!ret) ret = process_error_list(&spa->spa_errlist_last, uaddr, count); mutex_exit(&spa->spa_errlist_lock); mutex_exit(&spa->spa_errlog_lock); #endif return (ret); } /* * Called when a scrub completes. This simply set a bit which tells which AVL * tree to add new errors. spa_errlog_sync() is responsible for actually * syncing the changes to the underlying objects. */ void spa_errlog_rotate(spa_t *spa) { mutex_enter(&spa->spa_errlist_lock); spa->spa_scrub_finished = B_TRUE; mutex_exit(&spa->spa_errlist_lock); } /* * Discard any pending errors from the spa_t. Called when unloading a faulted * pool, as the errors encountered during the open cannot be synced to disk. */ void spa_errlog_drain(spa_t *spa) { spa_error_entry_t *se; void *cookie; mutex_enter(&spa->spa_errlist_lock); cookie = NULL; while ((se = avl_destroy_nodes(&spa->spa_errlist_last, &cookie)) != NULL) kmem_free(se, sizeof (spa_error_entry_t)); cookie = NULL; while ((se = avl_destroy_nodes(&spa->spa_errlist_scrub, &cookie)) != NULL) kmem_free(se, sizeof (spa_error_entry_t)); mutex_exit(&spa->spa_errlist_lock); } /* * Process a list of errors into the current on-disk log. */ static void sync_error_list(spa_t *spa, avl_tree_t *t, uint64_t *obj, dmu_tx_t *tx) { spa_error_entry_t *se; char buf[64]; void *cookie; if (avl_numnodes(t) != 0) { /* create log if necessary */ if (*obj == 0) *obj = zap_create(spa->spa_meta_objset, DMU_OT_ERROR_LOG, DMU_OT_NONE, 0, tx); /* add errors to the current log */ for (se = avl_first(t); se != NULL; se = AVL_NEXT(t, se)) { char *name = se->se_name ? se->se_name : ""; bookmark_to_name(&se->se_bookmark, buf, sizeof (buf)); (void) zap_update(spa->spa_meta_objset, *obj, buf, 1, strlen(name) + 1, name, tx); } /* purge the error list */ cookie = NULL; while ((se = avl_destroy_nodes(t, &cookie)) != NULL) kmem_free(se, sizeof (spa_error_entry_t)); } } /* * Sync the error log out to disk. This is a little tricky because the act of * writing the error log requires the spa_errlist_lock. So, we need to lock the * error lists, take a copy of the lists, and then reinitialize them. Then, we * drop the error list lock and take the error log lock, at which point we * do the errlog processing. Then, if we encounter an I/O error during this * process, we can successfully add the error to the list. Note that this will * result in the perpetual recycling of errors, but it is an unlikely situation * and not a performance critical operation. */ void spa_errlog_sync(spa_t *spa, uint64_t txg) { dmu_tx_t *tx; avl_tree_t scrub, last; int scrub_finished; mutex_enter(&spa->spa_errlist_lock); /* * Bail out early under normal circumstances. */ if (avl_numnodes(&spa->spa_errlist_scrub) == 0 && avl_numnodes(&spa->spa_errlist_last) == 0 && !spa->spa_scrub_finished) { mutex_exit(&spa->spa_errlist_lock); return; } spa_get_errlists(spa, &last, &scrub); scrub_finished = spa->spa_scrub_finished; spa->spa_scrub_finished = B_FALSE; mutex_exit(&spa->spa_errlist_lock); mutex_enter(&spa->spa_errlog_lock); tx = dmu_tx_create_assigned(spa->spa_dsl_pool, txg); /* * Sync out the current list of errors. */ sync_error_list(spa, &last, &spa->spa_errlog_last, tx); /* * Rotate the log if necessary. */ if (scrub_finished) { if (spa->spa_errlog_last != 0) VERIFY(dmu_object_free(spa->spa_meta_objset, spa->spa_errlog_last, tx) == 0); spa->spa_errlog_last = spa->spa_errlog_scrub; spa->spa_errlog_scrub = 0; sync_error_list(spa, &scrub, &spa->spa_errlog_last, tx); } /* * Sync out any pending scrub errors. */ sync_error_list(spa, &scrub, &spa->spa_errlog_scrub, tx); /* * Update the MOS to reflect the new values. */ (void) zap_update(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_ERRLOG_LAST, sizeof (uint64_t), 1, &spa->spa_errlog_last, tx); (void) zap_update(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_ERRLOG_SCRUB, sizeof (uint64_t), 1, &spa->spa_errlog_scrub, tx); dmu_tx_commit(tx); mutex_exit(&spa->spa_errlog_lock); } #if defined(_KERNEL) && defined(HAVE_SPL) /* error handling */ EXPORT_SYMBOL(spa_log_error); EXPORT_SYMBOL(spa_get_errlog_size); EXPORT_SYMBOL(spa_get_errlog); EXPORT_SYMBOL(spa_errlog_rotate); EXPORT_SYMBOL(spa_errlog_drain); EXPORT_SYMBOL(spa_errlog_sync); EXPORT_SYMBOL(spa_get_errlists); #endif