diff options
Diffstat (limited to 'module/zfs/spa.c')
| -rw-r--r-- | module/zfs/spa.c | 277 |
1 files changed, 277 insertions, 0 deletions
diff --git a/module/zfs/spa.c b/module/zfs/spa.c index 8330ab1ce..0f1a2a9eb 100644 --- a/module/zfs/spa.c +++ b/module/zfs/spa.c @@ -1541,6 +1541,8 @@ spa_unload(spa_t *spa) spa_import_progress_remove(spa_guid(spa)); spa_load_note(spa, "UNLOADING"); + spa_wake_waiters(spa); + /* * If the log space map feature is enabled and the pool is getting * exported (but not destroyed), we want to spend some time flushing @@ -2470,6 +2472,7 @@ livelist_delete_sync(void *arg, dmu_tx_t *tx) DMU_POOL_DELETED_CLONES, tx)); VERIFY0(zap_destroy(mos, zap_obj, tx)); spa->spa_livelists_to_delete = 0; + spa_notify_waiters(spa); } } @@ -6947,6 +6950,7 @@ spa_vdev_detach(spa_t *spa, uint64_t guid, uint64_t pguid, int replace_done) vdev_dirty(tvd, VDD_DTL, vd, txg); spa_event_notify(spa, vd, NULL, ESC_ZFS_VDEV_REMOVE); + spa_notify_waiters(spa); /* hang on to the spa before we release the lock */ spa_open_ref(spa, FTAG); @@ -9228,6 +9232,279 @@ spa_total_metaslabs(spa_t *spa) return (m); } +/* + * Notify any waiting threads that some activity has switched from being in- + * progress to not-in-progress so that the thread can wake up and determine + * whether it is finished waiting. + */ +void +spa_notify_waiters(spa_t *spa) +{ + /* + * Acquiring spa_activities_lock here prevents the cv_broadcast from + * happening between the waiting thread's check and cv_wait. + */ + mutex_enter(&spa->spa_activities_lock); + cv_broadcast(&spa->spa_activities_cv); + mutex_exit(&spa->spa_activities_lock); +} + +/* + * Notify any waiting threads that the pool is exporting, and then block until + * they are finished using the spa_t. + */ +void +spa_wake_waiters(spa_t *spa) +{ + mutex_enter(&spa->spa_activities_lock); + spa->spa_waiters_cancel = B_TRUE; + cv_broadcast(&spa->spa_activities_cv); + while (spa->spa_waiters != 0) + cv_wait(&spa->spa_waiters_cv, &spa->spa_activities_lock); + spa->spa_waiters_cancel = B_FALSE; + mutex_exit(&spa->spa_activities_lock); +} + +/* Whether the vdev or any of its descendants is initializing. */ +static boolean_t +spa_vdev_initializing_impl(vdev_t *vd) +{ + spa_t *spa = vd->vdev_spa; + boolean_t initializing; + + ASSERT(spa_config_held(spa, SCL_CONFIG | SCL_STATE, RW_READER)); + ASSERT(MUTEX_HELD(&spa->spa_activities_lock)); + + mutex_exit(&spa->spa_activities_lock); + mutex_enter(&vd->vdev_initialize_lock); + mutex_enter(&spa->spa_activities_lock); + + initializing = (vd->vdev_initialize_state == VDEV_INITIALIZE_ACTIVE); + mutex_exit(&vd->vdev_initialize_lock); + + if (initializing) + return (B_TRUE); + + for (int i = 0; i < vd->vdev_children; i++) { + if (spa_vdev_initializing_impl(vd->vdev_child[i])) + return (B_TRUE); + } + + return (B_FALSE); +} + +/* + * If use_guid is true, this checks whether the vdev specified by guid is + * being initialized. Otherwise, it checks whether any vdev in the pool is being + * initialized. The caller must hold the config lock and spa_activities_lock. + */ +static int +spa_vdev_initializing(spa_t *spa, boolean_t use_guid, uint64_t guid, + boolean_t *in_progress) +{ + mutex_exit(&spa->spa_activities_lock); + spa_config_enter(spa, SCL_CONFIG | SCL_STATE, FTAG, RW_READER); + mutex_enter(&spa->spa_activities_lock); + + vdev_t *vd; + if (use_guid) { + vd = spa_lookup_by_guid(spa, guid, B_FALSE); + if (vd == NULL || !vd->vdev_ops->vdev_op_leaf) { + spa_config_exit(spa, SCL_CONFIG | SCL_STATE, FTAG); + return (EINVAL); + } + } else { + vd = spa->spa_root_vdev; + } + + *in_progress = spa_vdev_initializing_impl(vd); + + spa_config_exit(spa, SCL_CONFIG | SCL_STATE, FTAG); + return (0); +} + +/* + * Locking for waiting threads + * --------------------------- + * + * Waiting threads need a way to check whether a given activity is in progress, + * and then, if it is, wait for it to complete. Each activity will have some + * in-memory representation of the relevant on-disk state which can be used to + * determine whether or not the activity is in progress. The in-memory state and + * the locking used to protect it will be different for each activity, and may + * not be suitable for use with a cvar (e.g., some state is protected by the + * config lock). To allow waiting threads to wait without any races, another + * lock, spa_activities_lock, is used. + * + * When the state is checked, both the activity-specific lock (if there is one) + * and spa_activities_lock are held. In some cases, the activity-specific lock + * is acquired explicitly (e.g. the config lock). In others, the locking is + * internal to some check (e.g. bpobj_is_empty). After checking, the waiting + * thread releases the activity-specific lock and, if the activity is in + * progress, then cv_waits using spa_activities_lock. + * + * The waiting thread is woken when another thread, one completing some + * activity, updates the state of the activity and then calls + * spa_notify_waiters, which will cv_broadcast. This 'completing' thread only + * needs to hold its activity-specific lock when updating the state, and this + * lock can (but doesn't have to) be dropped before calling spa_notify_waiters. + * + * Because spa_notify_waiters acquires spa_activities_lock before broadcasting, + * and because it is held when the waiting thread checks the state of the + * activity, it can never be the case that the completing thread both updates + * the activity state and cv_broadcasts in between the waiting thread's check + * and cv_wait. Thus, a waiting thread can never miss a wakeup. + * + * In order to prevent deadlock, when the waiting thread does its check, in some + * cases it will temporarily drop spa_activities_lock in order to acquire the + * activity-specific lock. The order in which spa_activities_lock and the + * activity specific lock are acquired in the waiting thread is determined by + * the order in which they are acquired in the completing thread; if the + * completing thread calls spa_notify_waiters with the activity-specific lock + * held, then the waiting thread must also acquire the activity-specific lock + * first. + */ + +static int +spa_activity_in_progress(spa_t *spa, zpool_wait_activity_t activity, + boolean_t use_tag, uint64_t tag, boolean_t *in_progress) +{ + int error = 0; + + ASSERT(MUTEX_HELD(&spa->spa_activities_lock)); + + switch (activity) { + case ZPOOL_WAIT_CKPT_DISCARD: + *in_progress = + (spa_feature_is_active(spa, SPA_FEATURE_POOL_CHECKPOINT) && + zap_contains(spa_meta_objset(spa), + DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_ZPOOL_CHECKPOINT) == + ENOENT); + break; + case ZPOOL_WAIT_FREE: + *in_progress = ((spa_version(spa) >= SPA_VERSION_DEADLISTS && + !bpobj_is_empty(&spa->spa_dsl_pool->dp_free_bpobj)) || + spa_feature_is_active(spa, SPA_FEATURE_ASYNC_DESTROY) || + spa_livelist_delete_check(spa)); + break; + case ZPOOL_WAIT_INITIALIZE: + error = spa_vdev_initializing(spa, use_tag, tag, in_progress); + break; + case ZPOOL_WAIT_REPLACE: + mutex_exit(&spa->spa_activities_lock); + spa_config_enter(spa, SCL_CONFIG | SCL_STATE, FTAG, RW_READER); + mutex_enter(&spa->spa_activities_lock); + + *in_progress = vdev_replace_in_progress(spa->spa_root_vdev); + spa_config_exit(spa, SCL_CONFIG | SCL_STATE, FTAG); + break; + case ZPOOL_WAIT_REMOVE: + *in_progress = (spa->spa_removing_phys.sr_state == + DSS_SCANNING); + break; + case ZPOOL_WAIT_RESILVER: + case ZPOOL_WAIT_SCRUB: + { + boolean_t scanning, paused, is_scrub; + dsl_scan_t *scn = spa->spa_dsl_pool->dp_scan; + + is_scrub = (scn->scn_phys.scn_func == POOL_SCAN_SCRUB); + scanning = (scn->scn_phys.scn_state == DSS_SCANNING); + paused = dsl_scan_is_paused_scrub(scn); + *in_progress = (scanning && !paused && + is_scrub == (activity == ZPOOL_WAIT_SCRUB)); + break; + } + default: + panic("unrecognized value for activity %d", activity); + } + + return (error); +} + +static int +spa_wait_common(const char *pool, zpool_wait_activity_t activity, + boolean_t use_tag, uint64_t tag, boolean_t *waited) +{ + /* + * The tag is used to distinguish between instances of an activity. + * 'initialize' is the only activity that we use this for. The other + * activities can only have a single instance in progress in a pool at + * one time, making the tag unnecessary. + * + * There can be multiple devices being replaced at once, but since they + * all finish once resilvering finishes, we don't bother keeping track + * of them individually, we just wait for them all to finish. + */ + if (use_tag && activity != ZPOOL_WAIT_INITIALIZE) + return (EINVAL); + + if (activity < 0 || activity >= ZPOOL_WAIT_NUM_ACTIVITIES) + return (EINVAL); + + spa_t *spa; + int error = spa_open(pool, &spa, FTAG); + if (error != 0) + return (error); + + /* + * Increment the spa's waiter count so that we can call spa_close and + * still ensure that the spa_t doesn't get freed before this thread is + * finished with it when the pool is exported. We want to call spa_close + * before we start waiting because otherwise the additional ref would + * prevent the pool from being exported or destroyed throughout the + * potentially long wait. + */ + mutex_enter(&spa->spa_activities_lock); + spa->spa_waiters++; + spa_close(spa, FTAG); + + *waited = B_FALSE; + for (;;) { + boolean_t in_progress; + error = spa_activity_in_progress(spa, activity, use_tag, tag, + &in_progress); + + if (!in_progress || spa->spa_waiters_cancel || error) + break; + + *waited = B_TRUE; + + if (cv_wait_sig(&spa->spa_activities_cv, + &spa->spa_activities_lock) == 0) { + error = EINTR; + break; + } + } + + spa->spa_waiters--; + cv_signal(&spa->spa_waiters_cv); + mutex_exit(&spa->spa_activities_lock); + + return (error); +} + +/* + * Wait for a particular instance of the specified activity to complete, where + * the instance is identified by 'tag' + */ +int +spa_wait_tag(const char *pool, zpool_wait_activity_t activity, uint64_t tag, + boolean_t *waited) +{ + return (spa_wait_common(pool, activity, B_TRUE, tag, waited)); +} + +/* + * Wait for all instances of the specified activity complete + */ +int +spa_wait(const char *pool, zpool_wait_activity_t activity, boolean_t *waited) +{ + + return (spa_wait_common(pool, activity, B_FALSE, 0, waited)); +} + sysevent_t * spa_event_create(spa_t *spa, vdev_t *vd, nvlist_t *hist_nvl, const char *name) { |