/* * 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) 2005, 2010, Oracle and/or its affiliates. All rights reserved. * Copyright (c) 2012, 2015 by Delphix. All rights reserved. */ /* * ZFS fault injection * * To handle fault injection, we keep track of a series of zinject_record_t * structures which describe which logical block(s) should be injected with a * fault. These are kept in a global list. Each record corresponds to a given * spa_t and maintains a special hold on the spa_t so that it cannot be deleted * or exported while the injection record exists. * * Device level injection is done using the 'zi_guid' field. If this is set, it * means that the error is destined for a particular device, not a piece of * data. * * This is a rather poor data structure and algorithm, but we don't expect more * than a few faults at any one time, so it should be sufficient for our needs. */ #include #include #include #include #include #include uint32_t zio_injection_enabled = 0; /* * Data describing each zinject handler registered on the system, and * contains the list node linking the handler in the global zinject * handler list. */ typedef struct inject_handler { int zi_id; spa_t *zi_spa; zinject_record_t zi_record; uint64_t *zi_lanes; int zi_next_lane; list_node_t zi_link; } inject_handler_t; /* * List of all zinject handlers registered on the system, protected by * the inject_lock defined below. */ static list_t inject_handlers; /* * This protects insertion into, and traversal of, the inject handler * list defined above; as well as the inject_delay_count. Any time a * handler is inserted or removed from the list, this lock should be * taken as a RW_WRITER; and any time traversal is done over the list * (without modification to it) this lock should be taken as a RW_READER. */ static krwlock_t inject_lock; /* * This holds the number of zinject delay handlers that have been * registered on the system. It is protected by the inject_lock defined * above. Thus modifications to this count must be a RW_WRITER of the * inject_lock, and reads of this count must be (at least) a RW_READER * of the lock. */ static int inject_delay_count = 0; /* * This lock is used only in zio_handle_io_delay(), refer to the comment * in that function for more details. */ static kmutex_t inject_delay_mtx; /* * Used to assign unique identifying numbers to each new zinject handler. */ static int inject_next_id = 1; /* * Returns true if the given record matches the I/O in progress. */ static boolean_t zio_match_handler(zbookmark_phys_t *zb, uint64_t type, zinject_record_t *record, int error) { /* * Check for a match against the MOS, which is based on type */ if (zb->zb_objset == DMU_META_OBJSET && record->zi_objset == DMU_META_OBJSET && record->zi_object == DMU_META_DNODE_OBJECT) { if (record->zi_type == DMU_OT_NONE || type == record->zi_type) return (record->zi_freq == 0 || spa_get_random(100) < record->zi_freq); else return (B_FALSE); } /* * Check for an exact match. */ if (zb->zb_objset == record->zi_objset && zb->zb_object == record->zi_object && zb->zb_level == record->zi_level && zb->zb_blkid >= record->zi_start && zb->zb_blkid <= record->zi_end && error == record->zi_error) return (record->zi_freq == 0 || spa_get_random(100) < record->zi_freq); return (B_FALSE); } /* * Panic the system when a config change happens in the function * specified by tag. */ void zio_handle_panic_injection(spa_t *spa, char *tag, uint64_t type) { inject_handler_t *handler; rw_enter(&inject_lock, RW_READER); for (handler = list_head(&inject_handlers); handler != NULL; handler = list_next(&inject_handlers, handler)) { if (spa != handler->zi_spa) continue; if (handler->zi_record.zi_type == type && strcmp(tag, handler->zi_record.zi_func) == 0) panic("Panic requested in function %s\n", tag); } rw_exit(&inject_lock); } /* * Determine if the I/O in question should return failure. Returns the errno * to be returned to the caller. */ int zio_handle_fault_injection(zio_t *zio, int error) { int ret = 0; inject_handler_t *handler; /* * Ignore I/O not associated with any logical data. */ if (zio->io_logical == NULL) return (0); /* * Currently, we only support fault injection on reads. */ if (zio->io_type != ZIO_TYPE_READ) return (0); rw_enter(&inject_lock, RW_READER); for (handler = list_head(&inject_handlers); handler != NULL; handler = list_next(&inject_handlers, handler)) { if (zio->io_spa != handler->zi_spa || handler->zi_record.zi_cmd != ZINJECT_DATA_FAULT) continue; /* If this handler matches, return EIO */ if (zio_match_handler(&zio->io_logical->io_bookmark, zio->io_bp ? BP_GET_TYPE(zio->io_bp) : DMU_OT_NONE, &handler->zi_record, error)) { ret = error; break; } } rw_exit(&inject_lock); return (ret); } /* * Determine if the zio is part of a label update and has an injection * handler associated with that portion of the label. Currently, we * allow error injection in either the nvlist or the uberblock region of * of the vdev label. */ int zio_handle_label_injection(zio_t *zio, int error) { inject_handler_t *handler; vdev_t *vd = zio->io_vd; uint64_t offset = zio->io_offset; int label; int ret = 0; if (offset >= VDEV_LABEL_START_SIZE && offset < vd->vdev_psize - VDEV_LABEL_END_SIZE) return (0); rw_enter(&inject_lock, RW_READER); for (handler = list_head(&inject_handlers); handler != NULL; handler = list_next(&inject_handlers, handler)) { uint64_t start = handler->zi_record.zi_start; uint64_t end = handler->zi_record.zi_end; if (handler->zi_record.zi_cmd != ZINJECT_LABEL_FAULT) continue; /* * The injection region is the relative offsets within a * vdev label. We must determine the label which is being * updated and adjust our region accordingly. */ label = vdev_label_number(vd->vdev_psize, offset); start = vdev_label_offset(vd->vdev_psize, label, start); end = vdev_label_offset(vd->vdev_psize, label, end); if (zio->io_vd->vdev_guid == handler->zi_record.zi_guid && (offset >= start && offset <= end)) { ret = error; break; } } rw_exit(&inject_lock); return (ret); } int zio_handle_device_injection(vdev_t *vd, zio_t *zio, int error) { inject_handler_t *handler; int ret = 0; /* * We skip over faults in the labels unless it's during * device open (i.e. zio == NULL). */ if (zio != NULL) { uint64_t offset = zio->io_offset; if (offset < VDEV_LABEL_START_SIZE || offset >= vd->vdev_psize - VDEV_LABEL_END_SIZE) return (0); } rw_enter(&inject_lock, RW_READER); for (handler = list_head(&inject_handlers); handler != NULL; handler = list_next(&inject_handlers, handler)) { if (handler->zi_record.zi_cmd != ZINJECT_DEVICE_FAULT) continue; if (vd->vdev_guid == handler->zi_record.zi_guid) { if (handler->zi_record.zi_failfast && (zio == NULL || (zio->io_flags & (ZIO_FLAG_IO_RETRY | ZIO_FLAG_TRYHARD)))) { continue; } /* Handle type specific I/O failures */ if (zio != NULL && handler->zi_record.zi_iotype != ZIO_TYPES && handler->zi_record.zi_iotype != zio->io_type) continue; if (handler->zi_record.zi_error == error) { /* * For a failed open, pretend like the device * has gone away. */ if (error == ENXIO) vd->vdev_stat.vs_aux = VDEV_AUX_OPEN_FAILED; /* * Treat these errors as if they had been * retried so that all the appropriate stats * and FMA events are generated. */ if (!handler->zi_record.zi_failfast && zio != NULL) zio->io_flags |= ZIO_FLAG_IO_RETRY; ret = error; break; } if (handler->zi_record.zi_error == ENXIO) { ret = SET_ERROR(EIO); break; } } } rw_exit(&inject_lock); return (ret); } /* * Simulate hardware that ignores cache flushes. For requested number * of seconds nix the actual writing to disk. */ void zio_handle_ignored_writes(zio_t *zio) { inject_handler_t *handler; rw_enter(&inject_lock, RW_READER); for (handler = list_head(&inject_handlers); handler != NULL; handler = list_next(&inject_handlers, handler)) { /* Ignore errors not destined for this pool */ if (zio->io_spa != handler->zi_spa || handler->zi_record.zi_cmd != ZINJECT_IGNORED_WRITES) continue; /* * Positive duration implies # of seconds, negative * a number of txgs */ if (handler->zi_record.zi_timer == 0) { if (handler->zi_record.zi_duration > 0) handler->zi_record.zi_timer = ddi_get_lbolt64(); else handler->zi_record.zi_timer = zio->io_txg; } /* Have a "problem" writing 60% of the time */ if (spa_get_random(100) < 60) zio->io_pipeline &= ~ZIO_VDEV_IO_STAGES; break; } rw_exit(&inject_lock); } void spa_handle_ignored_writes(spa_t *spa) { inject_handler_t *handler; if (zio_injection_enabled == 0) return; rw_enter(&inject_lock, RW_READER); for (handler = list_head(&inject_handlers); handler != NULL; handler = list_next(&inject_handlers, handler)) { if (spa != handler->zi_spa || handler->zi_record.zi_cmd != ZINJECT_IGNORED_WRITES) continue; if (handler->zi_record.zi_duration > 0) { VERIFY(handler->zi_record.zi_timer == 0 || ddi_time_after64( (int64_t)handler->zi_record.zi_timer + handler->zi_record.zi_duration * hz, ddi_get_lbolt64())); } else { /* duration is negative so the subtraction here adds */ VERIFY(handler->zi_record.zi_timer == 0 || handler->zi_record.zi_timer - handler->zi_record.zi_duration >= spa_syncing_txg(spa)); } } rw_exit(&inject_lock); } hrtime_t zio_handle_io_delay(zio_t *zio) { vdev_t *vd = zio->io_vd; inject_handler_t *min_handler = NULL; hrtime_t min_target = 0; inject_handler_t *handler; hrtime_t idle; hrtime_t busy; hrtime_t target; rw_enter(&inject_lock, RW_READER); /* * inject_delay_count is a subset of zio_injection_enabled that * is only incremented for delay handlers. These checks are * mainly added to remind the reader why we're not explicitly * checking zio_injection_enabled like the other functions. */ IMPLY(inject_delay_count > 0, zio_injection_enabled > 0); IMPLY(zio_injection_enabled == 0, inject_delay_count == 0); /* * If there aren't any inject delay handlers registered, then we * can short circuit and simply return 0 here. A value of zero * informs zio_delay_interrupt() that this request should not be * delayed. This short circuit keeps us from acquiring the * inject_delay_mutex unnecessarily. */ if (inject_delay_count == 0) { rw_exit(&inject_lock); return (0); } /* * Each inject handler has a number of "lanes" associated with * it. Each lane is able to handle requests independently of one * another, and at a latency defined by the inject handler * record's zi_timer field. Thus if a handler in configured with * a single lane with a 10ms latency, it will delay requests * such that only a single request is completed every 10ms. So, * if more than one request is attempted per each 10ms interval, * the average latency of the requests will be greater than * 10ms; but if only a single request is submitted each 10ms * interval the average latency will be 10ms. * * We need to acquire this mutex to prevent multiple concurrent * threads being assigned to the same lane of a given inject * handler. The mutex allows us to perform the following two * operations atomically: * * 1. determine the minimum handler and minimum target * value of all the possible handlers * 2. update that minimum handler's lane array * * Without atomicity, two (or more) threads could pick the same * lane in step (1), and then conflict with each other in step * (2). This could allow a single lane handler to process * multiple requests simultaneously, which shouldn't be possible. */ mutex_enter(&inject_delay_mtx); for (handler = list_head(&inject_handlers); handler != NULL; handler = list_next(&inject_handlers, handler)) { if (handler->zi_record.zi_cmd != ZINJECT_DELAY_IO) continue; if (handler->zi_record.zi_freq != 0 && spa_get_random(100) >= handler->zi_record.zi_freq) { continue; } if (vd->vdev_guid != handler->zi_record.zi_guid) continue; /* * Defensive; should never happen as the array allocation * occurs prior to inserting this handler on the list. */ ASSERT3P(handler->zi_lanes, !=, NULL); /* * This should never happen, the zinject command should * prevent a user from setting an IO delay with zero lanes. */ ASSERT3U(handler->zi_record.zi_nlanes, !=, 0); ASSERT3U(handler->zi_record.zi_nlanes, >, handler->zi_next_lane); /* * We want to issue this IO to the lane that will become * idle the soonest, so we compare the soonest this * specific handler can complete the IO with all other * handlers, to find the lowest value of all possible * lanes. We then use this lane to submit the request. * * Since each handler has a constant value for its * delay, we can just use the "next" lane for that * handler; as it will always be the lane with the * lowest value for that particular handler (i.e. the * lane that will become idle the soonest). This saves a * scan of each handler's lanes array. * * There's two cases to consider when determining when * this specific IO request should complete. If this * lane is idle, we want to "submit" the request now so * it will complete after zi_timer milliseconds. Thus, * we set the target to now + zi_timer. * * If the lane is busy, we want this request to complete * zi_timer milliseconds after the lane becomes idle. * Since the 'zi_lanes' array holds the time at which * each lane will become idle, we use that value to * determine when this request should complete. */ idle = handler->zi_record.zi_timer + gethrtime(); busy = handler->zi_record.zi_timer + handler->zi_lanes[handler->zi_next_lane]; target = MAX(idle, busy); if (min_handler == NULL) { min_handler = handler; min_target = target; continue; } ASSERT3P(min_handler, !=, NULL); ASSERT3U(min_target, !=, 0); /* * We don't yet increment the "next lane" variable since * we still might find a lower value lane in another * handler during any remaining iterations. Once we're * sure we've selected the absolute minimum, we'll claim * the lane and increment the handler's "next lane" * field below. */ if (target < min_target) { min_handler = handler; min_target = target; } } /* * 'min_handler' will be NULL if no IO delays are registered for * this vdev, otherwise it will point to the handler containing * the lane that will become idle the soonest. */ if (min_handler != NULL) { ASSERT3U(min_target, !=, 0); min_handler->zi_lanes[min_handler->zi_next_lane] = min_target; /* * If we've used all possible lanes for this handler, * loop back and start using the first lane again; * otherwise, just increment the lane index. */ min_handler->zi_next_lane = (min_handler->zi_next_lane + 1) % min_handler->zi_record.zi_nlanes; } mutex_exit(&inject_delay_mtx); rw_exit(&inject_lock); return (min_target); } /* * Create a new handler for the given record. We add it to the list, adding * a reference to the spa_t in the process. We increment zio_injection_enabled, * which is the switch to trigger all fault injection. */ int zio_inject_fault(char *name, int flags, int *id, zinject_record_t *record) { inject_handler_t *handler; int error; spa_t *spa; /* * If this is pool-wide metadata, make sure we unload the corresponding * spa_t, so that the next attempt to load it will trigger the fault. * We call spa_reset() to unload the pool appropriately. */ if (flags & ZINJECT_UNLOAD_SPA) if ((error = spa_reset(name)) != 0) return (error); if (record->zi_cmd == ZINJECT_DELAY_IO) { /* * A value of zero for the number of lanes or for the * delay time doesn't make sense. */ if (record->zi_timer == 0 || record->zi_nlanes == 0) return (SET_ERROR(EINVAL)); /* * The number of lanes is directly mapped to the size of * an array used by the handler. Thus, to ensure the * user doesn't trigger an allocation that's "too large" * we cap the number of lanes here. */ if (record->zi_nlanes >= UINT16_MAX) return (SET_ERROR(EINVAL)); } if (!(flags & ZINJECT_NULL)) { /* * spa_inject_ref() will add an injection reference, which will * prevent the pool from being removed from the namespace while * still allowing it to be unloaded. */ if ((spa = spa_inject_addref(name)) == NULL) return (SET_ERROR(ENOENT)); handler = kmem_alloc(sizeof (inject_handler_t), KM_SLEEP); handler->zi_spa = spa; handler->zi_record = *record; if (handler->zi_record.zi_cmd == ZINJECT_DELAY_IO) { handler->zi_lanes = kmem_zalloc( sizeof (*handler->zi_lanes) * handler->zi_record.zi_nlanes, KM_SLEEP); handler->zi_next_lane = 0; } else { handler->zi_lanes = NULL; handler->zi_next_lane = 0; } rw_enter(&inject_lock, RW_WRITER); /* * We can't move this increment into the conditional * above because we need to hold the RW_WRITER lock of * inject_lock, and we don't want to hold that while * allocating the handler's zi_lanes array. */ if (handler->zi_record.zi_cmd == ZINJECT_DELAY_IO) { ASSERT3S(inject_delay_count, >=, 0); inject_delay_count++; ASSERT3S(inject_delay_count, >, 0); } *id = handler->zi_id = inject_next_id++; list_insert_tail(&inject_handlers, handler); atomic_inc_32(&zio_injection_enabled); rw_exit(&inject_lock); } /* * Flush the ARC, so that any attempts to read this data will end up * going to the ZIO layer. Note that this is a little overkill, but * we don't have the necessary ARC interfaces to do anything else, and * fault injection isn't a performance critical path. */ if (flags & ZINJECT_FLUSH_ARC) /* * We must use FALSE to ensure arc_flush returns, since * we're not preventing concurrent ARC insertions. */ arc_flush(NULL, FALSE); return (0); } /* * Returns the next record with an ID greater than that supplied to the * function. Used to iterate over all handlers in the system. */ int zio_inject_list_next(int *id, char *name, size_t buflen, zinject_record_t *record) { inject_handler_t *handler; int ret; mutex_enter(&spa_namespace_lock); rw_enter(&inject_lock, RW_READER); for (handler = list_head(&inject_handlers); handler != NULL; handler = list_next(&inject_handlers, handler)) if (handler->zi_id > *id) break; if (handler) { *record = handler->zi_record; *id = handler->zi_id; (void) strncpy(name, spa_name(handler->zi_spa), buflen); ret = 0; } else { ret = SET_ERROR(ENOENT); } rw_exit(&inject_lock); mutex_exit(&spa_namespace_lock); return (ret); } /* * Clear the fault handler with the given identifier, or return ENOENT if none * exists. */ int zio_clear_fault(int id) { inject_handler_t *handler; rw_enter(&inject_lock, RW_WRITER); for (handler = list_head(&inject_handlers); handler != NULL; handler = list_next(&inject_handlers, handler)) if (handler->zi_id == id) break; if (handler == NULL) { rw_exit(&inject_lock); return (SET_ERROR(ENOENT)); } if (handler->zi_record.zi_cmd == ZINJECT_DELAY_IO) { ASSERT3S(inject_delay_count, >, 0); inject_delay_count--; ASSERT3S(inject_delay_count, >=, 0); } list_remove(&inject_handlers, handler); rw_exit(&inject_lock); if (handler->zi_record.zi_cmd == ZINJECT_DELAY_IO) { ASSERT3P(handler->zi_lanes, !=, NULL); kmem_free(handler->zi_lanes, sizeof (*handler->zi_lanes) * handler->zi_record.zi_nlanes); } else { ASSERT3P(handler->zi_lanes, ==, NULL); } spa_inject_delref(handler->zi_spa); kmem_free(handler, sizeof (inject_handler_t)); atomic_dec_32(&zio_injection_enabled); return (0); } void zio_inject_init(void) { rw_init(&inject_lock, NULL, RW_DEFAULT, NULL); mutex_init(&inject_delay_mtx, NULL, MUTEX_DEFAULT, NULL); list_create(&inject_handlers, sizeof (inject_handler_t), offsetof(inject_handler_t, zi_link)); } void zio_inject_fini(void) { list_destroy(&inject_handlers); mutex_destroy(&inject_delay_mtx); rw_destroy(&inject_lock); } #if defined(_KERNEL) && defined(HAVE_SPL) EXPORT_SYMBOL(zio_injection_enabled); EXPORT_SYMBOL(zio_inject_fault); EXPORT_SYMBOL(zio_inject_list_next); EXPORT_SYMBOL(zio_clear_fault); EXPORT_SYMBOL(zio_handle_fault_injection); EXPORT_SYMBOL(zio_handle_device_injection); EXPORT_SYMBOL(zio_handle_label_injection); #endif