/* * 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) 2011, 2018 by Delphix. All rights reserved. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * This file contains the necessary logic to remove vdevs from a * storage pool. Currently, the only devices that can be removed * are log, cache, and spare devices; and top level vdevs from a pool * w/o raidz or mirrors. (Note that members of a mirror can be removed * by the detach operation.) * * Log vdevs are removed by evacuating them and then turning the vdev * into a hole vdev while holding spa config locks. * * Top level vdevs are removed and converted into an indirect vdev via * a multi-step process: * * - Disable allocations from this device (spa_vdev_remove_top). * * - From a new thread (spa_vdev_remove_thread), copy data from * the removing vdev to a different vdev. The copy happens in open * context (spa_vdev_copy_impl) and issues a sync task * (vdev_mapping_sync) so the sync thread can update the partial * indirect mappings in core and on disk. * * - If a free happens during a removal, it is freed from the * removing vdev, and if it has already been copied, from the new * location as well (free_from_removing_vdev). * * - After the removal is completed, the copy thread converts the vdev * into an indirect vdev (vdev_remove_complete) before instructing * the sync thread to destroy the space maps and finish the removal * (spa_finish_removal). */ typedef struct vdev_copy_arg { metaslab_t *vca_msp; uint64_t vca_outstanding_bytes; kcondvar_t vca_cv; kmutex_t vca_lock; } vdev_copy_arg_t; /* * The maximum amount of memory we can use for outstanding i/o while * doing a device removal. This determines how much i/o we can have * in flight concurrently. */ int zfs_remove_max_copy_bytes = 64 * 1024 * 1024; /* * The largest contiguous segment that we will attempt to allocate when * removing a device. This can be no larger than SPA_MAXBLOCKSIZE. If * there is a performance problem with attempting to allocate large blocks, * consider decreasing this. */ int zfs_remove_max_segment = SPA_MAXBLOCKSIZE; /* * Allow a remap segment to span free chunks of at most this size. The main * impact of a larger span is that we will read and write larger, more * contiguous chunks, with more "unnecessary" data -- trading off bandwidth * for iops. The value here was chosen to align with * zfs_vdev_read_gap_limit, which is a similar concept when doing regular * reads (but there's no reason it has to be the same). * * Additionally, a higher span will have the following relatively minor * effects: * - the mapping will be smaller, since one entry can cover more allocated * segments * - more of the fragmentation in the removing device will be preserved * - we'll do larger allocations, which may fail and fall back on smaller * allocations */ int vdev_removal_max_span = 32 * 1024; /* * This is used by the test suite so that it can ensure that certain * actions happen while in the middle of a removal. */ unsigned long zfs_remove_max_bytes_pause = -1UL; #define VDEV_REMOVAL_ZAP_OBJS "lzap" static void spa_vdev_remove_thread(void *arg); static void spa_sync_removing_state(spa_t *spa, dmu_tx_t *tx) { VERIFY0(zap_update(spa->spa_dsl_pool->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_REMOVING, sizeof (uint64_t), sizeof (spa->spa_removing_phys) / sizeof (uint64_t), &spa->spa_removing_phys, tx)); } static nvlist_t * spa_nvlist_lookup_by_guid(nvlist_t **nvpp, int count, uint64_t target_guid) { for (int i = 0; i < count; i++) { uint64_t guid = fnvlist_lookup_uint64(nvpp[i], ZPOOL_CONFIG_GUID); if (guid == target_guid) return (nvpp[i]); } return (NULL); } static void spa_vdev_remove_aux(nvlist_t *config, char *name, nvlist_t **dev, int count, nvlist_t *dev_to_remove) { nvlist_t **newdev = NULL; if (count > 1) newdev = kmem_alloc((count - 1) * sizeof (void *), KM_SLEEP); for (int i = 0, j = 0; i < count; i++) { if (dev[i] == dev_to_remove) continue; VERIFY(nvlist_dup(dev[i], &newdev[j++], KM_SLEEP) == 0); } VERIFY(nvlist_remove(config, name, DATA_TYPE_NVLIST_ARRAY) == 0); VERIFY(nvlist_add_nvlist_array(config, name, newdev, count - 1) == 0); for (int i = 0; i < count - 1; i++) nvlist_free(newdev[i]); if (count > 1) kmem_free(newdev, (count - 1) * sizeof (void *)); } static spa_vdev_removal_t * spa_vdev_removal_create(vdev_t *vd) { spa_vdev_removal_t *svr = kmem_zalloc(sizeof (*svr), KM_SLEEP); mutex_init(&svr->svr_lock, NULL, MUTEX_DEFAULT, NULL); cv_init(&svr->svr_cv, NULL, CV_DEFAULT, NULL); svr->svr_allocd_segs = range_tree_create(NULL, NULL); svr->svr_vdev_id = vd->vdev_id; for (int i = 0; i < TXG_SIZE; i++) { svr->svr_frees[i] = range_tree_create(NULL, NULL); list_create(&svr->svr_new_segments[i], sizeof (vdev_indirect_mapping_entry_t), offsetof(vdev_indirect_mapping_entry_t, vime_node)); } return (svr); } void spa_vdev_removal_destroy(spa_vdev_removal_t *svr) { for (int i = 0; i < TXG_SIZE; i++) { ASSERT0(svr->svr_bytes_done[i]); ASSERT0(svr->svr_max_offset_to_sync[i]); range_tree_destroy(svr->svr_frees[i]); list_destroy(&svr->svr_new_segments[i]); } range_tree_destroy(svr->svr_allocd_segs); mutex_destroy(&svr->svr_lock); cv_destroy(&svr->svr_cv); kmem_free(svr, sizeof (*svr)); } /* * This is called as a synctask in the txg in which we will mark this vdev * as removing (in the config stored in the MOS). * * It begins the evacuation of a toplevel vdev by: * - initializing the spa_removing_phys which tracks this removal * - computing the amount of space to remove for accounting purposes * - dirtying all dbufs in the spa_config_object * - creating the spa_vdev_removal * - starting the spa_vdev_remove_thread */ static void vdev_remove_initiate_sync(void *arg, dmu_tx_t *tx) { int vdev_id = (uintptr_t)arg; spa_t *spa = dmu_tx_pool(tx)->dp_spa; vdev_t *vd = vdev_lookup_top(spa, vdev_id); vdev_indirect_config_t *vic = &vd->vdev_indirect_config; objset_t *mos = spa->spa_dsl_pool->dp_meta_objset; spa_vdev_removal_t *svr = NULL; ASSERTV(uint64_t txg = dmu_tx_get_txg(tx)); ASSERT3P(vd->vdev_ops, !=, &vdev_raidz_ops); svr = spa_vdev_removal_create(vd); ASSERT(vd->vdev_removing); ASSERT3P(vd->vdev_indirect_mapping, ==, NULL); spa_feature_incr(spa, SPA_FEATURE_DEVICE_REMOVAL, tx); if (spa_feature_is_enabled(spa, SPA_FEATURE_OBSOLETE_COUNTS)) { /* * By activating the OBSOLETE_COUNTS feature, we prevent * the pool from being downgraded and ensure that the * refcounts are precise. */ spa_feature_incr(spa, SPA_FEATURE_OBSOLETE_COUNTS, tx); uint64_t one = 1; VERIFY0(zap_add(spa->spa_meta_objset, vd->vdev_top_zap, VDEV_TOP_ZAP_OBSOLETE_COUNTS_ARE_PRECISE, sizeof (one), 1, &one, tx)); ASSERTV(boolean_t are_precise); ASSERT0(vdev_obsolete_counts_are_precise(vd, &are_precise)); ASSERT3B(are_precise, ==, B_TRUE); } vic->vic_mapping_object = vdev_indirect_mapping_alloc(mos, tx); vd->vdev_indirect_mapping = vdev_indirect_mapping_open(mos, vic->vic_mapping_object); vic->vic_births_object = vdev_indirect_births_alloc(mos, tx); vd->vdev_indirect_births = vdev_indirect_births_open(mos, vic->vic_births_object); spa->spa_removing_phys.sr_removing_vdev = vd->vdev_id; spa->spa_removing_phys.sr_start_time = gethrestime_sec(); spa->spa_removing_phys.sr_end_time = 0; spa->spa_removing_phys.sr_state = DSS_SCANNING; spa->spa_removing_phys.sr_to_copy = 0; spa->spa_removing_phys.sr_copied = 0; /* * Note: We can't use vdev_stat's vs_alloc for sr_to_copy, because * there may be space in the defer tree, which is free, but still * counted in vs_alloc. */ for (uint64_t i = 0; i < vd->vdev_ms_count; i++) { metaslab_t *ms = vd->vdev_ms[i]; if (ms->ms_sm == NULL) continue; /* * Sync tasks happen before metaslab_sync(), therefore * smp_alloc and sm_alloc must be the same. */ ASSERT3U(space_map_allocated(ms->ms_sm), ==, ms->ms_sm->sm_phys->smp_alloc); spa->spa_removing_phys.sr_to_copy += space_map_allocated(ms->ms_sm); /* * Space which we are freeing this txg does not need to * be copied. */ spa->spa_removing_phys.sr_to_copy -= range_tree_space(ms->ms_freeing); ASSERT0(range_tree_space(ms->ms_freed)); for (int t = 0; t < TXG_SIZE; t++) ASSERT0(range_tree_space(ms->ms_allocating[t])); } /* * Sync tasks are called before metaslab_sync(), so there should * be no already-synced metaslabs in the TXG_CLEAN list. */ ASSERT3P(txg_list_head(&vd->vdev_ms_list, TXG_CLEAN(txg)), ==, NULL); spa_sync_removing_state(spa, tx); /* * All blocks that we need to read the most recent mapping must be * stored on concrete vdevs. Therefore, we must dirty anything that * is read before spa_remove_init(). Specifically, the * spa_config_object. (Note that although we already modified the * spa_config_object in spa_sync_removing_state, that may not have * modified all blocks of the object.) */ dmu_object_info_t doi; VERIFY0(dmu_object_info(mos, DMU_POOL_DIRECTORY_OBJECT, &doi)); for (uint64_t offset = 0; offset < doi.doi_max_offset; ) { dmu_buf_t *dbuf; VERIFY0(dmu_buf_hold(mos, DMU_POOL_DIRECTORY_OBJECT, offset, FTAG, &dbuf, 0)); dmu_buf_will_dirty(dbuf, tx); offset += dbuf->db_size; dmu_buf_rele(dbuf, FTAG); } /* * Now that we've allocated the im_object, dirty the vdev to ensure * that the object gets written to the config on disk. */ vdev_config_dirty(vd); zfs_dbgmsg("starting removal thread for vdev %llu (%p) in txg %llu " "im_obj=%llu", vd->vdev_id, vd, dmu_tx_get_txg(tx), vic->vic_mapping_object); spa_history_log_internal(spa, "vdev remove started", tx, "%s vdev %llu %s", spa_name(spa), vd->vdev_id, (vd->vdev_path != NULL) ? vd->vdev_path : "-"); /* * Setting spa_vdev_removal causes subsequent frees to call * free_from_removing_vdev(). Note that we don't need any locking * because we are the sync thread, and metaslab_free_impl() is only * called from syncing context (potentially from a zio taskq thread, * but in any case only when there are outstanding free i/os, which * there are not). */ ASSERT3P(spa->spa_vdev_removal, ==, NULL); spa->spa_vdev_removal = svr; svr->svr_thread = thread_create(NULL, 0, spa_vdev_remove_thread, spa, 0, &p0, TS_RUN, minclsyspri); } /* * When we are opening a pool, we must read the mapping for each * indirect vdev in order from most recently removed to least * recently removed. We do this because the blocks for the mapping * of older indirect vdevs may be stored on more recently removed vdevs. * In order to read each indirect mapping object, we must have * initialized all more recently removed vdevs. */ int spa_remove_init(spa_t *spa) { int error; error = zap_lookup(spa->spa_dsl_pool->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_REMOVING, sizeof (uint64_t), sizeof (spa->spa_removing_phys) / sizeof (uint64_t), &spa->spa_removing_phys); if (error == ENOENT) { spa->spa_removing_phys.sr_state = DSS_NONE; spa->spa_removing_phys.sr_removing_vdev = -1; spa->spa_removing_phys.sr_prev_indirect_vdev = -1; spa->spa_indirect_vdevs_loaded = B_TRUE; return (0); } else if (error != 0) { return (error); } if (spa->spa_removing_phys.sr_state == DSS_SCANNING) { /* * We are currently removing a vdev. Create and * initialize a spa_vdev_removal_t from the bonus * buffer of the removing vdevs vdev_im_object, and * initialize its partial mapping. */ spa_config_enter(spa, SCL_STATE, FTAG, RW_READER); vdev_t *vd = vdev_lookup_top(spa, spa->spa_removing_phys.sr_removing_vdev); if (vd == NULL) { spa_config_exit(spa, SCL_STATE, FTAG); return (EINVAL); } vdev_indirect_config_t *vic = &vd->vdev_indirect_config; ASSERT(vdev_is_concrete(vd)); spa_vdev_removal_t *svr = spa_vdev_removal_create(vd); ASSERT3U(svr->svr_vdev_id, ==, vd->vdev_id); ASSERT(vd->vdev_removing); vd->vdev_indirect_mapping = vdev_indirect_mapping_open( spa->spa_meta_objset, vic->vic_mapping_object); vd->vdev_indirect_births = vdev_indirect_births_open( spa->spa_meta_objset, vic->vic_births_object); spa_config_exit(spa, SCL_STATE, FTAG); spa->spa_vdev_removal = svr; } spa_config_enter(spa, SCL_STATE, FTAG, RW_READER); uint64_t indirect_vdev_id = spa->spa_removing_phys.sr_prev_indirect_vdev; while (indirect_vdev_id != UINT64_MAX) { vdev_t *vd = vdev_lookup_top(spa, indirect_vdev_id); vdev_indirect_config_t *vic = &vd->vdev_indirect_config; ASSERT3P(vd->vdev_ops, ==, &vdev_indirect_ops); vd->vdev_indirect_mapping = vdev_indirect_mapping_open( spa->spa_meta_objset, vic->vic_mapping_object); vd->vdev_indirect_births = vdev_indirect_births_open( spa->spa_meta_objset, vic->vic_births_object); indirect_vdev_id = vic->vic_prev_indirect_vdev; } spa_config_exit(spa, SCL_STATE, FTAG); /* * Now that we've loaded all the indirect mappings, we can allow * reads from other blocks (e.g. via predictive prefetch). */ spa->spa_indirect_vdevs_loaded = B_TRUE; return (0); } void spa_restart_removal(spa_t *spa) { spa_vdev_removal_t *svr = spa->spa_vdev_removal; if (svr == NULL) return; /* * In general when this function is called there is no * removal thread running. The only scenario where this * is not true is during spa_import() where this function * is called twice [once from spa_import_impl() and * spa_async_resume()]. Thus, in the scenario where we * import a pool that has an ongoing removal we don't * want to spawn a second thread. */ if (svr->svr_thread != NULL) return; if (!spa_writeable(spa)) return; zfs_dbgmsg("restarting removal of %llu", svr->svr_vdev_id); svr->svr_thread = thread_create(NULL, 0, spa_vdev_remove_thread, spa, 0, &p0, TS_RUN, minclsyspri); } /* * Process freeing from a device which is in the middle of being removed. * We must handle this carefully so that we attempt to copy freed data, * and we correctly free already-copied data. */ void free_from_removing_vdev(vdev_t *vd, uint64_t offset, uint64_t size) { spa_t *spa = vd->vdev_spa; spa_vdev_removal_t *svr = spa->spa_vdev_removal; vdev_indirect_mapping_t *vim = vd->vdev_indirect_mapping; uint64_t txg = spa_syncing_txg(spa); uint64_t max_offset_yet = 0; ASSERT(vd->vdev_indirect_config.vic_mapping_object != 0); ASSERT3U(vd->vdev_indirect_config.vic_mapping_object, ==, vdev_indirect_mapping_object(vim)); ASSERT3U(vd->vdev_id, ==, svr->svr_vdev_id); mutex_enter(&svr->svr_lock); /* * Remove the segment from the removing vdev's spacemap. This * ensures that we will not attempt to copy this space (if the * removal thread has not yet visited it), and also ensures * that we know what is actually allocated on the new vdevs * (needed if we cancel the removal). * * Note: we must do the metaslab_free_concrete() with the svr_lock * held, so that the remove_thread can not load this metaslab and then * visit this offset between the time that we metaslab_free_concrete() * and when we check to see if it has been visited. * * Note: The checkpoint flag is set to false as having/taking * a checkpoint and removing a device can't happen at the same * time. */ ASSERT(!spa_has_checkpoint(spa)); metaslab_free_concrete(vd, offset, size, B_FALSE); uint64_t synced_size = 0; uint64_t synced_offset = 0; uint64_t max_offset_synced = vdev_indirect_mapping_max_offset(vim); if (offset < max_offset_synced) { /* * The mapping for this offset is already on disk. * Free from the new location. * * Note that we use svr_max_synced_offset because it is * updated atomically with respect to the in-core mapping. * By contrast, vim_max_offset is not. * * This block may be split between a synced entry and an * in-flight or unvisited entry. Only process the synced * portion of it here. */ synced_size = MIN(size, max_offset_synced - offset); synced_offset = offset; ASSERT3U(max_offset_yet, <=, max_offset_synced); max_offset_yet = max_offset_synced; DTRACE_PROBE3(remove__free__synced, spa_t *, spa, uint64_t, offset, uint64_t, synced_size); size -= synced_size; offset += synced_size; } /* * Look at all in-flight txgs starting from the currently syncing one * and see if a section of this free is being copied. By starting from * this txg and iterating forward, we might find that this region * was copied in two different txgs and handle it appropriately. */ for (int i = 0; i < TXG_CONCURRENT_STATES; i++) { int txgoff = (txg + i) & TXG_MASK; if (size > 0 && offset < svr->svr_max_offset_to_sync[txgoff]) { /* * The mapping for this offset is in flight, and * will be synced in txg+i. */ uint64_t inflight_size = MIN(size, svr->svr_max_offset_to_sync[txgoff] - offset); DTRACE_PROBE4(remove__free__inflight, spa_t *, spa, uint64_t, offset, uint64_t, inflight_size, uint64_t, txg + i); /* * We copy data in order of increasing offset. * Therefore the max_offset_to_sync[] must increase * (or be zero, indicating that nothing is being * copied in that txg). */ if (svr->svr_max_offset_to_sync[txgoff] != 0) { ASSERT3U(svr->svr_max_offset_to_sync[txgoff], >=, max_offset_yet); max_offset_yet = svr->svr_max_offset_to_sync[txgoff]; } /* * We've already committed to copying this segment: * we have allocated space elsewhere in the pool for * it and have an IO outstanding to copy the data. We * cannot free the space before the copy has * completed, or else the copy IO might overwrite any * new data. To free that space, we record the * segment in the appropriate svr_frees tree and free * the mapped space later, in the txg where we have * completed the copy and synced the mapping (see * vdev_mapping_sync). */ range_tree_add(svr->svr_frees[txgoff], offset, inflight_size); size -= inflight_size; offset += inflight_size; /* * This space is already accounted for as being * done, because it is being copied in txg+i. * However, if i!=0, then it is being copied in * a future txg. If we crash after this txg * syncs but before txg+i syncs, then the space * will be free. Therefore we must account * for the space being done in *this* txg * (when it is freed) rather than the future txg * (when it will be copied). */ ASSERT3U(svr->svr_bytes_done[txgoff], >=, inflight_size); svr->svr_bytes_done[txgoff] -= inflight_size; svr->svr_bytes_done[txg & TXG_MASK] += inflight_size; } } ASSERT0(svr->svr_max_offset_to_sync[TXG_CLEAN(txg) & TXG_MASK]); if (size > 0) { /* * The copy thread has not yet visited this offset. Ensure * that it doesn't. */ DTRACE_PROBE3(remove__free__unvisited, spa_t *, spa, uint64_t, offset, uint64_t, size); if (svr->svr_allocd_segs != NULL) range_tree_clear(svr->svr_allocd_segs, offset, size); /* * Since we now do not need to copy this data, for * accounting purposes we have done our job and can count * it as completed. */ svr->svr_bytes_done[txg & TXG_MASK] += size; } mutex_exit(&svr->svr_lock); /* * Now that we have dropped svr_lock, process the synced portion * of this free. */ if (synced_size > 0) { vdev_indirect_mark_obsolete(vd, synced_offset, synced_size); /* * Note: this can only be called from syncing context, * and the vdev_indirect_mapping is only changed from the * sync thread, so we don't need svr_lock while doing * metaslab_free_impl_cb. */ boolean_t checkpoint = B_FALSE; vdev_indirect_ops.vdev_op_remap(vd, synced_offset, synced_size, metaslab_free_impl_cb, &checkpoint); } } /* * Stop an active removal and update the spa_removing phys. */ static void spa_finish_removal(spa_t *spa, dsl_scan_state_t state, dmu_tx_t *tx) { spa_vdev_removal_t *svr = spa->spa_vdev_removal; ASSERT3U(dmu_tx_get_txg(tx), ==, spa_syncing_txg(spa)); /* Ensure the removal thread has completed before we free the svr. */ spa_vdev_remove_suspend(spa); ASSERT(state == DSS_FINISHED || state == DSS_CANCELED); if (state == DSS_FINISHED) { spa_removing_phys_t *srp = &spa->spa_removing_phys; vdev_t *vd = vdev_lookup_top(spa, svr->svr_vdev_id); vdev_indirect_config_t *vic = &vd->vdev_indirect_config; if (srp->sr_prev_indirect_vdev != UINT64_MAX) { vdev_t *pvd; pvd = vdev_lookup_top(spa, srp->sr_prev_indirect_vdev); ASSERT3P(pvd->vdev_ops, ==, &vdev_indirect_ops); } vic->vic_prev_indirect_vdev = srp->sr_prev_indirect_vdev; srp->sr_prev_indirect_vdev = vd->vdev_id; } spa->spa_removing_phys.sr_state = state; spa->spa_removing_phys.sr_end_time = gethrestime_sec(); spa->spa_vdev_removal = NULL; spa_vdev_removal_destroy(svr); spa_sync_removing_state(spa, tx); vdev_config_dirty(spa->spa_root_vdev); } static void free_mapped_segment_cb(void *arg, uint64_t offset, uint64_t size) { vdev_t *vd = arg; vdev_indirect_mark_obsolete(vd, offset, size); boolean_t checkpoint = B_FALSE; vdev_indirect_ops.vdev_op_remap(vd, offset, size, metaslab_free_impl_cb, &checkpoint); } /* * On behalf of the removal thread, syncs an incremental bit more of * the indirect mapping to disk and updates the in-memory mapping. * Called as a sync task in every txg that the removal thread makes progress. */ static void vdev_mapping_sync(void *arg, dmu_tx_t *tx) { spa_vdev_removal_t *svr = arg; spa_t *spa = dmu_tx_pool(tx)->dp_spa; vdev_t *vd = vdev_lookup_top(spa, svr->svr_vdev_id); ASSERTV(vdev_indirect_config_t *vic = &vd->vdev_indirect_config); uint64_t txg = dmu_tx_get_txg(tx); vdev_indirect_mapping_t *vim = vd->vdev_indirect_mapping; ASSERT(vic->vic_mapping_object != 0); ASSERT3U(txg, ==, spa_syncing_txg(spa)); vdev_indirect_mapping_add_entries(vim, &svr->svr_new_segments[txg & TXG_MASK], tx); vdev_indirect_births_add_entry(vd->vdev_indirect_births, vdev_indirect_mapping_max_offset(vim), dmu_tx_get_txg(tx), tx); /* * Free the copied data for anything that was freed while the * mapping entries were in flight. */ mutex_enter(&svr->svr_lock); range_tree_vacate(svr->svr_frees[txg & TXG_MASK], free_mapped_segment_cb, vd); ASSERT3U(svr->svr_max_offset_to_sync[txg & TXG_MASK], >=, vdev_indirect_mapping_max_offset(vim)); svr->svr_max_offset_to_sync[txg & TXG_MASK] = 0; mutex_exit(&svr->svr_lock); spa_sync_removing_state(spa, tx); } typedef struct vdev_copy_segment_arg { spa_t *vcsa_spa; dva_t *vcsa_dest_dva; uint64_t vcsa_txg; range_tree_t *vcsa_obsolete_segs; } vdev_copy_segment_arg_t; static void unalloc_seg(void *arg, uint64_t start, uint64_t size) { vdev_copy_segment_arg_t *vcsa = arg; spa_t *spa = vcsa->vcsa_spa; blkptr_t bp = { { { {0} } } }; BP_SET_BIRTH(&bp, TXG_INITIAL, TXG_INITIAL); BP_SET_LSIZE(&bp, size); BP_SET_PSIZE(&bp, size); BP_SET_COMPRESS(&bp, ZIO_COMPRESS_OFF); BP_SET_CHECKSUM(&bp, ZIO_CHECKSUM_OFF); BP_SET_TYPE(&bp, DMU_OT_NONE); BP_SET_LEVEL(&bp, 0); BP_SET_DEDUP(&bp, 0); BP_SET_BYTEORDER(&bp, ZFS_HOST_BYTEORDER); DVA_SET_VDEV(&bp.blk_dva[0], DVA_GET_VDEV(vcsa->vcsa_dest_dva)); DVA_SET_OFFSET(&bp.blk_dva[0], DVA_GET_OFFSET(vcsa->vcsa_dest_dva) + start); DVA_SET_ASIZE(&bp.blk_dva[0], size); zio_free(spa, vcsa->vcsa_txg, &bp); } /* * All reads and writes associated with a call to spa_vdev_copy_segment() * are done. */ static void spa_vdev_copy_segment_done(zio_t *zio) { vdev_copy_segment_arg_t *vcsa = zio->io_private; range_tree_vacate(vcsa->vcsa_obsolete_segs, unalloc_seg, vcsa); range_tree_destroy(vcsa->vcsa_obsolete_segs); kmem_free(vcsa, sizeof (*vcsa)); spa_config_exit(zio->io_spa, SCL_STATE, zio->io_spa); } /* * The write of the new location is done. */ static void spa_vdev_copy_segment_write_done(zio_t *zio) { vdev_copy_arg_t *vca = zio->io_private; abd_free(zio->io_abd); mutex_enter(&vca->vca_lock); vca->vca_outstanding_bytes -= zio->io_size; cv_signal(&vca->vca_cv); mutex_exit(&vca->vca_lock); } /* * The read of the old location is done. The parent zio is the write to * the new location. Allow it to start. */ static void spa_vdev_copy_segment_read_done(zio_t *zio) { zio_nowait(zio_unique_parent(zio)); } /* * If the old and new vdevs are mirrors, we will read both sides of the old * mirror, and write each copy to the corresponding side of the new mirror. * If the old and new vdevs have a different number of children, we will do * this as best as possible. Since we aren't verifying checksums, this * ensures that as long as there's a good copy of the data, we'll have a * good copy after the removal, even if there's silent damage to one side * of the mirror. If we're removing a mirror that has some silent damage, * we'll have exactly the same damage in the new location (assuming that * the new location is also a mirror). * * We accomplish this by creating a tree of zio_t's, with as many writes as * there are "children" of the new vdev (a non-redundant vdev counts as one * child, a 2-way mirror has 2 children, etc). Each write has an associated * read from a child of the old vdev. Typically there will be the same * number of children of the old and new vdevs. However, if there are more * children of the new vdev, some child(ren) of the old vdev will be issued * multiple reads. If there are more children of the old vdev, some copies * will be dropped. * * For example, the tree of zio_t's for a 2-way mirror is: * * null * / \ * write(new vdev, child 0) write(new vdev, child 1) * | | * read(old vdev, child 0) read(old vdev, child 1) * * Child zio's complete before their parents complete. However, zio's * created with zio_vdev_child_io() may be issued before their children * complete. In this case we need to make sure that the children (reads) * complete before the parents (writes) are *issued*. We do this by not * calling zio_nowait() on each write until its corresponding read has * completed. * * The spa_config_lock must be held while zio's created by * zio_vdev_child_io() are in progress, to ensure that the vdev tree does * not change (e.g. due to a concurrent "zpool attach/detach"). The "null" * zio is needed to release the spa_config_lock after all the reads and * writes complete. (Note that we can't grab the config lock for each read, * because it is not reentrant - we could deadlock with a thread waiting * for a write lock.) */ static void spa_vdev_copy_one_child(vdev_copy_arg_t *vca, zio_t *nzio, vdev_t *source_vd, uint64_t source_offset, vdev_t *dest_child_vd, uint64_t dest_offset, int dest_id, uint64_t size) { ASSERT3U(spa_config_held(nzio->io_spa, SCL_ALL, RW_READER), !=, 0); mutex_enter(&vca->vca_lock); vca->vca_outstanding_bytes += size; mutex_exit(&vca->vca_lock); abd_t *abd = abd_alloc_for_io(size, B_FALSE); vdev_t *source_child_vd; if (source_vd->vdev_ops == &vdev_mirror_ops && dest_id != -1) { /* * Source and dest are both mirrors. Copy from the same * child id as we are copying to (wrapping around if there * are more dest children than source children). */ source_child_vd = source_vd->vdev_child[dest_id % source_vd->vdev_children]; } else { source_child_vd = source_vd; } zio_t *write_zio = zio_vdev_child_io(nzio, NULL, dest_child_vd, dest_offset, abd, size, ZIO_TYPE_WRITE, ZIO_PRIORITY_REMOVAL, ZIO_FLAG_CANFAIL, spa_vdev_copy_segment_write_done, vca); zio_nowait(zio_vdev_child_io(write_zio, NULL, source_child_vd, source_offset, abd, size, ZIO_TYPE_READ, ZIO_PRIORITY_REMOVAL, ZIO_FLAG_CANFAIL, spa_vdev_copy_segment_read_done, vca)); } /* * Allocate a new location for this segment, and create the zio_t's to * read from the old location and write to the new location. */ static int spa_vdev_copy_segment(vdev_t *vd, range_tree_t *segs, uint64_t maxalloc, uint64_t txg, vdev_copy_arg_t *vca, zio_alloc_list_t *zal) { metaslab_group_t *mg = vd->vdev_mg; spa_t *spa = vd->vdev_spa; spa_vdev_removal_t *svr = spa->spa_vdev_removal; vdev_indirect_mapping_entry_t *entry; dva_t dst = {{ 0 }}; uint64_t start = range_tree_min(segs); ASSERT3U(maxalloc, <=, SPA_MAXBLOCKSIZE); uint64_t size = range_tree_span(segs); if (range_tree_span(segs) > maxalloc) { /* * We can't allocate all the segments. Prefer to end * the allocation at the end of a segment, thus avoiding * additional split blocks. */ range_seg_t search; avl_index_t where; search.rs_start = start + maxalloc; search.rs_end = search.rs_start; range_seg_t *rs = avl_find(&segs->rt_root, &search, &where); if (rs == NULL) { rs = avl_nearest(&segs->rt_root, where, AVL_BEFORE); } else { rs = AVL_PREV(&segs->rt_root, rs); } if (rs != NULL) { size = rs->rs_end - start; } else { /* * There are no segments that end before maxalloc. * I.e. the first segment is larger than maxalloc, * so we must split it. */ size = maxalloc; } } ASSERT3U(size, <=, maxalloc); /* * An allocation class might not have any remaining vdevs or space */ metaslab_class_t *mc = mg->mg_class; if (mc != spa_normal_class(spa) && mc->mc_groups <= 1) mc = spa_normal_class(spa); int error = metaslab_alloc_dva(spa, mc, size, &dst, 0, NULL, txg, 0, zal, 0); if (error == ENOSPC && mc != spa_normal_class(spa)) { error = metaslab_alloc_dva(spa, spa_normal_class(spa), size, &dst, 0, NULL, txg, 0, zal, 0); } if (error != 0) return (error); /* * Determine the ranges that are not actually needed. Offsets are * relative to the start of the range to be copied (i.e. relative to the * local variable "start"). */ range_tree_t *obsolete_segs = range_tree_create(NULL, NULL); range_seg_t *rs = avl_first(&segs->rt_root); ASSERT3U(rs->rs_start, ==, start); uint64_t prev_seg_end = rs->rs_end; while ((rs = AVL_NEXT(&segs->rt_root, rs)) != NULL) { if (rs->rs_start >= start + size) { break; } else { range_tree_add(obsolete_segs, prev_seg_end - start, rs->rs_start - prev_seg_end); } prev_seg_end = rs->rs_end; } /* We don't end in the middle of an obsolete range */ ASSERT3U(start + size, <=, prev_seg_end); range_tree_clear(segs, start, size); /* * We can't have any padding of the allocated size, otherwise we will * misunderstand what's allocated, and the size of the mapping. * The caller ensures this will be true by passing in a size that is * aligned to the worst (highest) ashift in the pool. */ ASSERT3U(DVA_GET_ASIZE(&dst), ==, size); entry = kmem_zalloc(sizeof (vdev_indirect_mapping_entry_t), KM_SLEEP); DVA_MAPPING_SET_SRC_OFFSET(&entry->vime_mapping, start); entry->vime_mapping.vimep_dst = dst; if (spa_feature_is_enabled(spa, SPA_FEATURE_OBSOLETE_COUNTS)) { entry->vime_obsolete_count = range_tree_space(obsolete_segs); } vdev_copy_segment_arg_t *vcsa = kmem_zalloc(sizeof (*vcsa), KM_SLEEP); vcsa->vcsa_dest_dva = &entry->vime_mapping.vimep_dst; vcsa->vcsa_obsolete_segs = obsolete_segs; vcsa->vcsa_spa = spa; vcsa->vcsa_txg = txg; /* * See comment before spa_vdev_copy_one_child(). */ spa_config_enter(spa, SCL_STATE, spa, RW_READER); zio_t *nzio = zio_null(spa->spa_txg_zio[txg & TXG_MASK], spa, NULL, spa_vdev_copy_segment_done, vcsa, 0); vdev_t *dest_vd = vdev_lookup_top(spa, DVA_GET_VDEV(&dst)); if (dest_vd->vdev_ops == &vdev_mirror_ops) { for (int i = 0; i < dest_vd->vdev_children; i++) { vdev_t *child = dest_vd->vdev_child[i]; spa_vdev_copy_one_child(vca, nzio, vd, start, child, DVA_GET_OFFSET(&dst), i, size); } } else { spa_vdev_copy_one_child(vca, nzio, vd, start, dest_vd, DVA_GET_OFFSET(&dst), -1, size); } zio_nowait(nzio); list_insert_tail(&svr->svr_new_segments[txg & TXG_MASK], entry); ASSERT3U(start + size, <=, vd->vdev_ms_count << vd->vdev_ms_shift); vdev_dirty(vd, 0, NULL, txg); return (0); } /* * Complete the removal of a toplevel vdev. This is called as a * synctask in the same txg that we will sync out the new config (to the * MOS object) which indicates that this vdev is indirect. */ static void vdev_remove_complete_sync(void *arg, dmu_tx_t *tx) { spa_vdev_removal_t *svr = arg; spa_t *spa = dmu_tx_pool(tx)->dp_spa; vdev_t *vd = vdev_lookup_top(spa, svr->svr_vdev_id); ASSERT3P(vd->vdev_ops, ==, &vdev_indirect_ops); for (int i = 0; i < TXG_SIZE; i++) { ASSERT0(svr->svr_bytes_done[i]); } ASSERT3U(spa->spa_removing_phys.sr_copied, ==, spa->spa_removing_phys.sr_to_copy); vdev_destroy_spacemaps(vd, tx); /* destroy leaf zaps, if any */ ASSERT3P(svr->svr_zaplist, !=, NULL); for (nvpair_t *pair = nvlist_next_nvpair(svr->svr_zaplist, NULL); pair != NULL; pair = nvlist_next_nvpair(svr->svr_zaplist, pair)) { vdev_destroy_unlink_zap(vd, fnvpair_value_uint64(pair), tx); } fnvlist_free(svr->svr_zaplist); spa_finish_removal(dmu_tx_pool(tx)->dp_spa, DSS_FINISHED, tx); /* vd->vdev_path is not available here */ spa_history_log_internal(spa, "vdev remove completed", tx, "%s vdev %llu", spa_name(spa), vd->vdev_id); } static void vdev_remove_enlist_zaps(vdev_t *vd, nvlist_t *zlist) { ASSERT3P(zlist, !=, NULL); ASSERT3P(vd->vdev_ops, !=, &vdev_raidz_ops); if (vd->vdev_leaf_zap != 0) { char zkey[32]; (void) snprintf(zkey, sizeof (zkey), "%s-%llu", VDEV_REMOVAL_ZAP_OBJS, (u_longlong_t)vd->vdev_leaf_zap); fnvlist_add_uint64(zlist, zkey, vd->vdev_leaf_zap); } for (uint64_t id = 0; id < vd->vdev_children; id++) { vdev_remove_enlist_zaps(vd->vdev_child[id], zlist); } } static void vdev_remove_replace_with_indirect(vdev_t *vd, uint64_t txg) { vdev_t *ivd; dmu_tx_t *tx; spa_t *spa = vd->vdev_spa; spa_vdev_removal_t *svr = spa->spa_vdev_removal; /* * First, build a list of leaf zaps to be destroyed. * This is passed to the sync context thread, * which does the actual unlinking. */ svr->svr_zaplist = fnvlist_alloc(); vdev_remove_enlist_zaps(vd, svr->svr_zaplist); ivd = vdev_add_parent(vd, &vdev_indirect_ops); ivd->vdev_removing = 0; vd->vdev_leaf_zap = 0; vdev_remove_child(ivd, vd); vdev_compact_children(ivd); ASSERT(!list_link_active(&vd->vdev_state_dirty_node)); tx = dmu_tx_create_assigned(spa->spa_dsl_pool, txg); dsl_sync_task_nowait(spa->spa_dsl_pool, vdev_remove_complete_sync, svr, 0, ZFS_SPACE_CHECK_NONE, tx); dmu_tx_commit(tx); /* * Indicate that this thread has exited. * After this, we can not use svr. */ mutex_enter(&svr->svr_lock); svr->svr_thread = NULL; cv_broadcast(&svr->svr_cv); mutex_exit(&svr->svr_lock); } /* * Complete the removal of a toplevel vdev. This is called in open * context by the removal thread after we have copied all vdev's data. */ static void vdev_remove_complete(spa_t *spa) { uint64_t txg; /* * Wait for any deferred frees to be synced before we call * vdev_metaslab_fini() */ txg_wait_synced(spa->spa_dsl_pool, 0); txg = spa_vdev_enter(spa); vdev_t *vd = vdev_lookup_top(spa, spa->spa_vdev_removal->svr_vdev_id); sysevent_t *ev = spa_event_create(spa, vd, NULL, ESC_ZFS_VDEV_REMOVE_DEV); zfs_dbgmsg("finishing device removal for vdev %llu in txg %llu", vd->vdev_id, txg); /* * Discard allocation state. */ if (vd->vdev_mg != NULL) { vdev_metaslab_fini(vd); metaslab_group_destroy(vd->vdev_mg); vd->vdev_mg = NULL; } ASSERT0(vd->vdev_stat.vs_space); ASSERT0(vd->vdev_stat.vs_dspace); vdev_remove_replace_with_indirect(vd, txg); /* * We now release the locks, allowing spa_sync to run and finish the * removal via vdev_remove_complete_sync in syncing context. * * Note that we hold on to the vdev_t that has been replaced. Since * it isn't part of the vdev tree any longer, it can't be concurrently * manipulated, even while we don't have the config lock. */ (void) spa_vdev_exit(spa, NULL, txg, 0); /* * Top ZAP should have been transferred to the indirect vdev in * vdev_remove_replace_with_indirect. */ ASSERT0(vd->vdev_top_zap); /* * Leaf ZAP should have been moved in vdev_remove_replace_with_indirect. */ ASSERT0(vd->vdev_leaf_zap); txg = spa_vdev_enter(spa); (void) vdev_label_init(vd, 0, VDEV_LABEL_REMOVE); /* * Request to update the config and the config cachefile. */ vdev_config_dirty(spa->spa_root_vdev); (void) spa_vdev_exit(spa, vd, txg, 0); if (ev != NULL) spa_event_post(ev); } /* * Evacuates a segment of size at most max_alloc from the vdev * via repeated calls to spa_vdev_copy_segment. If an allocation * fails, the pool is probably too fragmented to handle such a * large size, so decrease max_alloc so that the caller will not try * this size again this txg. */ static void spa_vdev_copy_impl(vdev_t *vd, spa_vdev_removal_t *svr, vdev_copy_arg_t *vca, uint64_t *max_alloc, dmu_tx_t *tx) { uint64_t txg = dmu_tx_get_txg(tx); spa_t *spa = dmu_tx_pool(tx)->dp_spa; mutex_enter(&svr->svr_lock); /* * Determine how big of a chunk to copy. We can allocate up * to max_alloc bytes, and we can span up to vdev_removal_max_span * bytes of unallocated space at a time. "segs" will track the * allocated segments that we are copying. We may also be copying * free segments (of up to vdev_removal_max_span bytes). */ range_tree_t *segs = range_tree_create(NULL, NULL); for (;;) { range_seg_t *rs = range_tree_first(svr->svr_allocd_segs); if (rs == NULL) break; uint64_t seg_length; if (range_tree_is_empty(segs)) { /* need to truncate the first seg based on max_alloc */ seg_length = MIN(rs->rs_end - rs->rs_start, *max_alloc); } else { if (rs->rs_start - range_tree_max(segs) > vdev_removal_max_span) { /* * Including this segment would cause us to * copy a larger unneeded chunk than is allowed. */ break; } else if (rs->rs_end - range_tree_min(segs) > *max_alloc) { /* * This additional segment would extend past * max_alloc. Rather than splitting this * segment, leave it for the next mapping. */ break; } else { seg_length = rs->rs_end - rs->rs_start; } } range_tree_add(segs, rs->rs_start, seg_length); range_tree_remove(svr->svr_allocd_segs, rs->rs_start, seg_length); } if (range_tree_is_empty(segs)) { mutex_exit(&svr->svr_lock); range_tree_destroy(segs); return; } if (svr->svr_max_offset_to_sync[txg & TXG_MASK] == 0) { dsl_sync_task_nowait(dmu_tx_pool(tx), vdev_mapping_sync, svr, 0, ZFS_SPACE_CHECK_NONE, tx); } svr->svr_max_offset_to_sync[txg & TXG_MASK] = range_tree_max(segs); /* * Note: this is the amount of *allocated* space * that we are taking care of each txg. */ svr->svr_bytes_done[txg & TXG_MASK] += range_tree_space(segs); mutex_exit(&svr->svr_lock); zio_alloc_list_t zal; metaslab_trace_init(&zal); uint64_t thismax = SPA_MAXBLOCKSIZE; while (!range_tree_is_empty(segs)) { int error = spa_vdev_copy_segment(vd, segs, thismax, txg, vca, &zal); if (error == ENOSPC) { /* * Cut our segment in half, and don't try this * segment size again this txg. Note that the * allocation size must be aligned to the highest * ashift in the pool, so that the allocation will * not be padded out to a multiple of the ashift, * which could cause us to think that this mapping * is larger than we intended. */ ASSERT3U(spa->spa_max_ashift, >=, SPA_MINBLOCKSHIFT); ASSERT3U(spa->spa_max_ashift, ==, spa->spa_min_ashift); uint64_t attempted = MIN(range_tree_span(segs), thismax); thismax = P2ROUNDUP(attempted / 2, 1 << spa->spa_max_ashift); /* * The minimum-size allocation can not fail. */ ASSERT3U(attempted, >, 1 << spa->spa_max_ashift); *max_alloc = attempted - (1 << spa->spa_max_ashift); } else { ASSERT0(error); /* * We've performed an allocation, so reset the * alloc trace list. */ metaslab_trace_fini(&zal); metaslab_trace_init(&zal); } } metaslab_trace_fini(&zal); range_tree_destroy(segs); } /* * The removal thread operates in open context. It iterates over all * allocated space in the vdev, by loading each metaslab's spacemap. * For each contiguous segment of allocated space (capping the segment * size at SPA_MAXBLOCKSIZE), we: * - Allocate space for it on another vdev. * - Create a new mapping from the old location to the new location * (as a record in svr_new_segments). * - Initiate a physical read zio to get the data off the removing disk. * - In the read zio's done callback, initiate a physical write zio to * write it to the new vdev. * Note that all of this will take effect when a particular TXG syncs. * The sync thread ensures that all the phys reads and writes for the syncing * TXG have completed (see spa_txg_zio) and writes the new mappings to disk * (see vdev_mapping_sync()). */ static void spa_vdev_remove_thread(void *arg) { spa_t *spa = arg; spa_vdev_removal_t *svr = spa->spa_vdev_removal; vdev_copy_arg_t vca; uint64_t max_alloc = zfs_remove_max_segment; uint64_t last_txg = 0; spa_config_enter(spa, SCL_CONFIG, FTAG, RW_READER); vdev_t *vd = vdev_lookup_top(spa, svr->svr_vdev_id); vdev_indirect_mapping_t *vim = vd->vdev_indirect_mapping; uint64_t start_offset = vdev_indirect_mapping_max_offset(vim); ASSERT3P(vd->vdev_ops, !=, &vdev_indirect_ops); ASSERT(vdev_is_concrete(vd)); ASSERT(vd->vdev_removing); ASSERT(vd->vdev_indirect_config.vic_mapping_object != 0); ASSERT(vim != NULL); mutex_init(&vca.vca_lock, NULL, MUTEX_DEFAULT, NULL); cv_init(&vca.vca_cv, NULL, CV_DEFAULT, NULL); vca.vca_outstanding_bytes = 0; mutex_enter(&svr->svr_lock); /* * Start from vim_max_offset so we pick up where we left off * if we are restarting the removal after opening the pool. */ uint64_t msi; for (msi = start_offset >> vd->vdev_ms_shift; msi < vd->vdev_ms_count && !svr->svr_thread_exit; msi++) { metaslab_t *msp = vd->vdev_ms[msi]; ASSERT3U(msi, <=, vd->vdev_ms_count); ASSERT0(range_tree_space(svr->svr_allocd_segs)); mutex_enter(&msp->ms_sync_lock); mutex_enter(&msp->ms_lock); /* * Assert nothing in flight -- ms_*tree is empty. */ for (int i = 0; i < TXG_SIZE; i++) { ASSERT0(range_tree_space(msp->ms_allocating[i])); } /* * If the metaslab has ever been allocated from (ms_sm!=NULL), * read the allocated segments from the space map object * into svr_allocd_segs. Since we do this while holding * svr_lock and ms_sync_lock, concurrent frees (which * would have modified the space map) will wait for us * to finish loading the spacemap, and then take the * appropriate action (see free_from_removing_vdev()). */ if (msp->ms_sm != NULL) { space_map_t *sm = NULL; /* * We have to open a new space map here, because * ms_sm's sm_length and sm_alloc may not reflect * what's in the object contents, if we are in between * metaslab_sync() and metaslab_sync_done(). */ VERIFY0(space_map_open(&sm, spa->spa_dsl_pool->dp_meta_objset, msp->ms_sm->sm_object, msp->ms_sm->sm_start, msp->ms_sm->sm_size, msp->ms_sm->sm_shift)); space_map_update(sm); VERIFY0(space_map_load(sm, svr->svr_allocd_segs, SM_ALLOC)); space_map_close(sm); range_tree_walk(msp->ms_freeing, range_tree_remove, svr->svr_allocd_segs); /* * When we are resuming from a paused removal (i.e. * when importing a pool with a removal in progress), * discard any state that we have already processed. */ range_tree_clear(svr->svr_allocd_segs, 0, start_offset); } mutex_exit(&msp->ms_lock); mutex_exit(&msp->ms_sync_lock); vca.vca_msp = msp; zfs_dbgmsg("copying %llu segments for metaslab %llu", avl_numnodes(&svr->svr_allocd_segs->rt_root), msp->ms_id); while (!svr->svr_thread_exit && !range_tree_is_empty(svr->svr_allocd_segs)) { mutex_exit(&svr->svr_lock); /* * We need to periodically drop the config lock so that * writers can get in. Additionally, we can't wait * for a txg to sync while holding a config lock * (since a waiting writer could cause a 3-way deadlock * with the sync thread, which also gets a config * lock for reader). So we can't hold the config lock * while calling dmu_tx_assign(). */ spa_config_exit(spa, SCL_CONFIG, FTAG); /* * This delay will pause the removal around the point * specified by zfs_remove_max_bytes_pause. We do this * solely from the test suite or during debugging. */ uint64_t bytes_copied = spa->spa_removing_phys.sr_copied; for (int i = 0; i < TXG_SIZE; i++) bytes_copied += svr->svr_bytes_done[i]; while (zfs_remove_max_bytes_pause <= bytes_copied && !svr->svr_thread_exit) delay(hz); mutex_enter(&vca.vca_lock); while (vca.vca_outstanding_bytes > zfs_remove_max_copy_bytes) { cv_wait(&vca.vca_cv, &vca.vca_lock); } mutex_exit(&vca.vca_lock); dmu_tx_t *tx = dmu_tx_create_dd(spa_get_dsl(spa)->dp_mos_dir); dmu_tx_hold_space(tx, SPA_MAXBLOCKSIZE); VERIFY0(dmu_tx_assign(tx, TXG_WAIT)); uint64_t txg = dmu_tx_get_txg(tx); /* * Reacquire the vdev_config lock. The vdev_t * that we're removing may have changed, e.g. due * to a vdev_attach or vdev_detach. */ spa_config_enter(spa, SCL_CONFIG, FTAG, RW_READER); vd = vdev_lookup_top(spa, svr->svr_vdev_id); if (txg != last_txg) max_alloc = zfs_remove_max_segment; last_txg = txg; spa_vdev_copy_impl(vd, svr, &vca, &max_alloc, tx); dmu_tx_commit(tx); mutex_enter(&svr->svr_lock); } } mutex_exit(&svr->svr_lock); spa_config_exit(spa, SCL_CONFIG, FTAG); /* * Wait for all copies to finish before cleaning up the vca. */ txg_wait_synced(spa->spa_dsl_pool, 0); ASSERT0(vca.vca_outstanding_bytes); mutex_destroy(&vca.vca_lock); cv_destroy(&vca.vca_cv); if (svr->svr_thread_exit) { mutex_enter(&svr->svr_lock); range_tree_vacate(svr->svr_allocd_segs, NULL, NULL); svr->svr_thread = NULL; cv_broadcast(&svr->svr_cv); mutex_exit(&svr->svr_lock); } else { ASSERT0(range_tree_space(svr->svr_allocd_segs)); vdev_remove_complete(spa); } } void spa_vdev_remove_suspend(spa_t *spa) { spa_vdev_removal_t *svr = spa->spa_vdev_removal; if (svr == NULL) return; mutex_enter(&svr->svr_lock); svr->svr_thread_exit = B_TRUE; while (svr->svr_thread != NULL) cv_wait(&svr->svr_cv, &svr->svr_lock); svr->svr_thread_exit = B_FALSE; mutex_exit(&svr->svr_lock); } /* ARGSUSED */ static int spa_vdev_remove_cancel_check(void *arg, dmu_tx_t *tx) { spa_t *spa = dmu_tx_pool(tx)->dp_spa; if (spa->spa_vdev_removal == NULL) return (ENOTACTIVE); return (0); } /* * Cancel a removal by freeing all entries from the partial mapping * and marking the vdev as no longer being removing. */ /* ARGSUSED */ static void spa_vdev_remove_cancel_sync(void *arg, dmu_tx_t *tx) { spa_t *spa = dmu_tx_pool(tx)->dp_spa; spa_vdev_removal_t *svr = spa->spa_vdev_removal; vdev_t *vd = vdev_lookup_top(spa, svr->svr_vdev_id); vdev_indirect_config_t *vic = &vd->vdev_indirect_config; vdev_indirect_mapping_t *vim = vd->vdev_indirect_mapping; objset_t *mos = spa->spa_meta_objset; ASSERT3P(svr->svr_thread, ==, NULL); spa_feature_decr(spa, SPA_FEATURE_DEVICE_REMOVAL, tx); boolean_t are_precise; VERIFY0(vdev_obsolete_counts_are_precise(vd, &are_precise)); if (are_precise) { spa_feature_decr(spa, SPA_FEATURE_OBSOLETE_COUNTS, tx); VERIFY0(zap_remove(spa->spa_meta_objset, vd->vdev_top_zap, VDEV_TOP_ZAP_OBSOLETE_COUNTS_ARE_PRECISE, tx)); } uint64_t obsolete_sm_object; VERIFY0(vdev_obsolete_sm_object(vd, &obsolete_sm_object)); if (obsolete_sm_object != 0) { ASSERT(vd->vdev_obsolete_sm != NULL); ASSERT3U(obsolete_sm_object, ==, space_map_object(vd->vdev_obsolete_sm)); space_map_free(vd->vdev_obsolete_sm, tx); VERIFY0(zap_remove(spa->spa_meta_objset, vd->vdev_top_zap, VDEV_TOP_ZAP_INDIRECT_OBSOLETE_SM, tx)); space_map_close(vd->vdev_obsolete_sm); vd->vdev_obsolete_sm = NULL; spa_feature_decr(spa, SPA_FEATURE_OBSOLETE_COUNTS, tx); } for (int i = 0; i < TXG_SIZE; i++) { ASSERT(list_is_empty(&svr->svr_new_segments[i])); ASSERT3U(svr->svr_max_offset_to_sync[i], <=, vdev_indirect_mapping_max_offset(vim)); } for (uint64_t msi = 0; msi < vd->vdev_ms_count; msi++) { metaslab_t *msp = vd->vdev_ms[msi]; if (msp->ms_start >= vdev_indirect_mapping_max_offset(vim)) break; ASSERT0(range_tree_space(svr->svr_allocd_segs)); mutex_enter(&msp->ms_lock); /* * Assert nothing in flight -- ms_*tree is empty. */ for (int i = 0; i < TXG_SIZE; i++) ASSERT0(range_tree_space(msp->ms_allocating[i])); for (int i = 0; i < TXG_DEFER_SIZE; i++) ASSERT0(range_tree_space(msp->ms_defer[i])); ASSERT0(range_tree_space(msp->ms_freed)); if (msp->ms_sm != NULL) { /* * Assert that the in-core spacemap has the same * length as the on-disk one, so we can use the * existing in-core spacemap to load it from disk. */ ASSERT3U(msp->ms_sm->sm_alloc, ==, msp->ms_sm->sm_phys->smp_alloc); ASSERT3U(msp->ms_sm->sm_length, ==, msp->ms_sm->sm_phys->smp_objsize); mutex_enter(&svr->svr_lock); VERIFY0(space_map_load(msp->ms_sm, svr->svr_allocd_segs, SM_ALLOC)); range_tree_walk(msp->ms_freeing, range_tree_remove, svr->svr_allocd_segs); /* * Clear everything past what has been synced, * because we have not allocated mappings for it yet. */ uint64_t syncd = vdev_indirect_mapping_max_offset(vim); uint64_t sm_end = msp->ms_sm->sm_start + msp->ms_sm->sm_size; if (sm_end > syncd) range_tree_clear(svr->svr_allocd_segs, syncd, sm_end - syncd); mutex_exit(&svr->svr_lock); } mutex_exit(&msp->ms_lock); mutex_enter(&svr->svr_lock); range_tree_vacate(svr->svr_allocd_segs, free_mapped_segment_cb, vd); mutex_exit(&svr->svr_lock); } /* * Note: this must happen after we invoke free_mapped_segment_cb, * because it adds to the obsolete_segments. */ range_tree_vacate(vd->vdev_obsolete_segments, NULL, NULL); ASSERT3U(vic->vic_mapping_object, ==, vdev_indirect_mapping_object(vd->vdev_indirect_mapping)); vdev_indirect_mapping_close(vd->vdev_indirect_mapping); vd->vdev_indirect_mapping = NULL; vdev_indirect_mapping_free(mos, vic->vic_mapping_object, tx); vic->vic_mapping_object = 0; ASSERT3U(vic->vic_births_object, ==, vdev_indirect_births_object(vd->vdev_indirect_births)); vdev_indirect_births_close(vd->vdev_indirect_births); vd->vdev_indirect_births = NULL; vdev_indirect_births_free(mos, vic->vic_births_object, tx); vic->vic_births_object = 0; /* * We may have processed some frees from the removing vdev in this * txg, thus increasing svr_bytes_done; discard that here to * satisfy the assertions in spa_vdev_removal_destroy(). * Note that future txg's can not have any bytes_done, because * future TXG's are only modified from open context, and we have * already shut down the copying thread. */ svr->svr_bytes_done[dmu_tx_get_txg(tx) & TXG_MASK] = 0; spa_finish_removal(spa, DSS_CANCELED, tx); vd->vdev_removing = B_FALSE; vdev_config_dirty(vd); zfs_dbgmsg("canceled device removal for vdev %llu in %llu", vd->vdev_id, dmu_tx_get_txg(tx)); spa_history_log_internal(spa, "vdev remove canceled", tx, "%s vdev %llu %s", spa_name(spa), vd->vdev_id, (vd->vdev_path != NULL) ? vd->vdev_path : "-"); } int spa_vdev_remove_cancel(spa_t *spa) { spa_vdev_remove_suspend(spa); if (spa->spa_vdev_removal == NULL) return (ENOTACTIVE); uint64_t vdid = spa->spa_vdev_removal->svr_vdev_id; int error = dsl_sync_task(spa->spa_name, spa_vdev_remove_cancel_check, spa_vdev_remove_cancel_sync, NULL, 0, ZFS_SPACE_CHECK_EXTRA_RESERVED); if (error == 0) { spa_config_enter(spa, SCL_ALLOC | SCL_VDEV, FTAG, RW_WRITER); vdev_t *vd = vdev_lookup_top(spa, vdid); metaslab_group_activate(vd->vdev_mg); spa_config_exit(spa, SCL_ALLOC | SCL_VDEV, FTAG); } return (error); } /* * Called every sync pass of every txg if there's a svr. */ void svr_sync(spa_t *spa, dmu_tx_t *tx) { spa_vdev_removal_t *svr = spa->spa_vdev_removal; int txgoff = dmu_tx_get_txg(tx) & TXG_MASK; /* * This check is necessary so that we do not dirty the * DIRECTORY_OBJECT via spa_sync_removing_state() when there * is nothing to do. Dirtying it every time would prevent us * from syncing-to-convergence. */ if (svr->svr_bytes_done[txgoff] == 0) return; /* * Update progress accounting. */ spa->spa_removing_phys.sr_copied += svr->svr_bytes_done[txgoff]; svr->svr_bytes_done[txgoff] = 0; spa_sync_removing_state(spa, tx); } static void vdev_remove_make_hole_and_free(vdev_t *vd) { uint64_t id = vd->vdev_id; spa_t *spa = vd->vdev_spa; vdev_t *rvd = spa->spa_root_vdev; boolean_t last_vdev = (id == (rvd->vdev_children - 1)); ASSERT(MUTEX_HELD(&spa_namespace_lock)); ASSERT(spa_config_held(spa, SCL_ALL, RW_WRITER) == SCL_ALL); vdev_free(vd); if (last_vdev) { vdev_compact_children(rvd); } else { vd = vdev_alloc_common(spa, id, 0, &vdev_hole_ops); vdev_add_child(rvd, vd); } vdev_config_dirty(rvd); /* * Reassess the health of our root vdev. */ vdev_reopen(rvd); } /* * Remove a log device. The config lock is held for the specified TXG. */ static int spa_vdev_remove_log(vdev_t *vd, uint64_t *txg) { metaslab_group_t *mg = vd->vdev_mg; spa_t *spa = vd->vdev_spa; int error = 0; ASSERT(vd->vdev_islog); ASSERT(vd == vd->vdev_top); /* * Stop allocating from this vdev. */ metaslab_group_passivate(mg); /* * Wait for the youngest allocations and frees to sync, * and then wait for the deferral of those frees to finish. */ spa_vdev_config_exit(spa, NULL, *txg + TXG_CONCURRENT_STATES + TXG_DEFER_SIZE, 0, FTAG); /* * Evacuate the device. We don't hold the config lock as writer * since we need to do I/O but we do keep the * spa_namespace_lock held. Once this completes the device * should no longer have any blocks allocated on it. */ if (vd->vdev_islog) { if (vd->vdev_stat.vs_alloc != 0) error = spa_reset_logs(spa); } *txg = spa_vdev_config_enter(spa); if (error != 0) { metaslab_group_activate(mg); return (error); } ASSERT0(vd->vdev_stat.vs_alloc); /* * The evacuation succeeded. Remove any remaining MOS metadata * associated with this vdev, and wait for these changes to sync. */ vd->vdev_removing = B_TRUE; vdev_dirty_leaves(vd, VDD_DTL, *txg); vdev_config_dirty(vd); spa_history_log_internal(spa, "vdev remove", NULL, "%s vdev %llu (log) %s", spa_name(spa), vd->vdev_id, (vd->vdev_path != NULL) ? vd->vdev_path : "-"); spa_vdev_config_exit(spa, NULL, *txg, 0, FTAG); *txg = spa_vdev_config_enter(spa); sysevent_t *ev = spa_event_create(spa, vd, NULL, ESC_ZFS_VDEV_REMOVE_DEV); ASSERT(MUTEX_HELD(&spa_namespace_lock)); ASSERT(spa_config_held(spa, SCL_ALL, RW_WRITER) == SCL_ALL); /* The top ZAP should have been destroyed by vdev_remove_empty. */ ASSERT0(vd->vdev_top_zap); /* The leaf ZAP should have been destroyed by vdev_dtl_sync. */ ASSERT0(vd->vdev_leaf_zap); (void) vdev_label_init(vd, 0, VDEV_LABEL_REMOVE); if (list_link_active(&vd->vdev_state_dirty_node)) vdev_state_clean(vd); if (list_link_active(&vd->vdev_config_dirty_node)) vdev_config_clean(vd); /* * Clean up the vdev namespace. */ vdev_remove_make_hole_and_free(vd); if (ev != NULL) spa_event_post(ev); return (0); } static int spa_vdev_remove_top_check(vdev_t *vd) { spa_t *spa = vd->vdev_spa; if (vd != vd->vdev_top) return (SET_ERROR(ENOTSUP)); if (!spa_feature_is_enabled(spa, SPA_FEATURE_DEVICE_REMOVAL)) return (SET_ERROR(ENOTSUP)); /* available space in the pool's normal class */ uint64_t available = dsl_dir_space_available( spa->spa_dsl_pool->dp_root_dir, NULL, 0, B_TRUE); metaslab_class_t *mc = vd->vdev_mg->mg_class; /* * When removing a vdev from an allocation class that has * remaining vdevs, include available space from the class. */ if (mc != spa_normal_class(spa) && mc->mc_groups > 1) { uint64_t class_avail = metaslab_class_get_space(mc) - metaslab_class_get_alloc(mc); /* add class space, adjusted for overhead */ available += (class_avail * 94) / 100; } /* * There has to be enough free space to remove the * device and leave double the "slop" space (i.e. we * must leave at least 3% of the pool free, in addition to * the normal slop space). */ if (available < vd->vdev_stat.vs_dspace + spa_get_slop_space(spa)) { return (SET_ERROR(ENOSPC)); } /* * There can not be a removal in progress. */ if (spa->spa_removing_phys.sr_state == DSS_SCANNING) return (SET_ERROR(EBUSY)); /* * The device must have all its data. */ if (!vdev_dtl_empty(vd, DTL_MISSING) || !vdev_dtl_empty(vd, DTL_OUTAGE)) return (SET_ERROR(EBUSY)); /* * The device must be healthy. */ if (!vdev_readable(vd)) return (SET_ERROR(EIO)); /* * All vdevs in normal class must have the same ashift. */ if (spa->spa_max_ashift != spa->spa_min_ashift) { return (SET_ERROR(EINVAL)); } /* * All vdevs in normal class must have the same ashift * and not be raidz. */ vdev_t *rvd = spa->spa_root_vdev; int num_indirect = 0; for (uint64_t id = 0; id < rvd->vdev_children; id++) { vdev_t *cvd = rvd->vdev_child[id]; if (cvd->vdev_ashift != 0 && !cvd->vdev_islog) ASSERT3U(cvd->vdev_ashift, ==, spa->spa_max_ashift); if (cvd->vdev_ops == &vdev_indirect_ops) num_indirect++; if (!vdev_is_concrete(cvd)) continue; if (cvd->vdev_ops == &vdev_raidz_ops) return (SET_ERROR(EINVAL)); /* * Need the mirror to be mirror of leaf vdevs only */ if (cvd->vdev_ops == &vdev_mirror_ops) { for (uint64_t cid = 0; cid < cvd->vdev_children; cid++) { if (!cvd->vdev_child[cid]->vdev_ops-> vdev_op_leaf) return (SET_ERROR(EINVAL)); } } } return (0); } /* * Initiate removal of a top-level vdev, reducing the total space in the pool. * The config lock is held for the specified TXG. Once initiated, * evacuation of all allocated space (copying it to other vdevs) happens * in the background (see spa_vdev_remove_thread()), and can be canceled * (see spa_vdev_remove_cancel()). If successful, the vdev will * be transformed to an indirect vdev (see spa_vdev_remove_complete()). */ static int spa_vdev_remove_top(vdev_t *vd, uint64_t *txg) { spa_t *spa = vd->vdev_spa; int error; /* * Check for errors up-front, so that we don't waste time * passivating the metaslab group and clearing the ZIL if there * are errors. */ error = spa_vdev_remove_top_check(vd); if (error != 0) return (error); /* * Stop allocating from this vdev. Note that we must check * that this is not the only device in the pool before * passivating, otherwise we will not be able to make * progress because we can't allocate from any vdevs. * The above check for sufficient free space serves this * purpose. */ metaslab_group_t *mg = vd->vdev_mg; metaslab_group_passivate(mg); /* * Wait for the youngest allocations and frees to sync, * and then wait for the deferral of those frees to finish. */ spa_vdev_config_exit(spa, NULL, *txg + TXG_CONCURRENT_STATES + TXG_DEFER_SIZE, 0, FTAG); /* * We must ensure that no "stubby" log blocks are allocated * on the device to be removed. These blocks could be * written at any time, including while we are in the middle * of copying them. */ error = spa_reset_logs(spa); *txg = spa_vdev_config_enter(spa); /* * Things might have changed while the config lock was dropped * (e.g. space usage). Check for errors again. */ if (error == 0) error = spa_vdev_remove_top_check(vd); if (error != 0) { metaslab_group_activate(mg); return (error); } vd->vdev_removing = B_TRUE; vdev_dirty_leaves(vd, VDD_DTL, *txg); vdev_config_dirty(vd); dmu_tx_t *tx = dmu_tx_create_assigned(spa->spa_dsl_pool, *txg); dsl_sync_task_nowait(spa->spa_dsl_pool, vdev_remove_initiate_sync, (void *)(uintptr_t)vd->vdev_id, 0, ZFS_SPACE_CHECK_NONE, tx); dmu_tx_commit(tx); return (0); } /* * Remove a device from the pool. * * Removing a device from the vdev namespace requires several steps * and can take a significant amount of time. As a result we use * the spa_vdev_config_[enter/exit] functions which allow us to * grab and release the spa_config_lock while still holding the namespace * lock. During each step the configuration is synced out. */ int spa_vdev_remove(spa_t *spa, uint64_t guid, boolean_t unspare) { vdev_t *vd; nvlist_t **spares, **l2cache, *nv; uint64_t txg = 0; uint_t nspares, nl2cache; int error = 0; boolean_t locked = MUTEX_HELD(&spa_namespace_lock); sysevent_t *ev = NULL; ASSERT(spa_writeable(spa)); if (!locked) txg = spa_vdev_enter(spa); ASSERT(MUTEX_HELD(&spa_namespace_lock)); if (spa_feature_is_active(spa, SPA_FEATURE_POOL_CHECKPOINT)) { error = (spa_has_checkpoint(spa)) ? ZFS_ERR_CHECKPOINT_EXISTS : ZFS_ERR_DISCARDING_CHECKPOINT; if (!locked) return (spa_vdev_exit(spa, NULL, txg, error)); return (error); } vd = spa_lookup_by_guid(spa, guid, B_FALSE); if (spa->spa_spares.sav_vdevs != NULL && nvlist_lookup_nvlist_array(spa->spa_spares.sav_config, ZPOOL_CONFIG_SPARES, &spares, &nspares) == 0 && (nv = spa_nvlist_lookup_by_guid(spares, nspares, guid)) != NULL) { /* * Only remove the hot spare if it's not currently in use * in this pool. */ if (vd == NULL || unspare) { if (vd == NULL) vd = spa_lookup_by_guid(spa, guid, B_TRUE); ev = spa_event_create(spa, vd, NULL, ESC_ZFS_VDEV_REMOVE_AUX); char *nvstr = fnvlist_lookup_string(nv, ZPOOL_CONFIG_PATH); spa_history_log_internal(spa, "vdev remove", NULL, "%s vdev (%s) %s", spa_name(spa), VDEV_TYPE_SPARE, nvstr); spa_vdev_remove_aux(spa->spa_spares.sav_config, ZPOOL_CONFIG_SPARES, spares, nspares, nv); spa_load_spares(spa); spa->spa_spares.sav_sync = B_TRUE; } else { error = SET_ERROR(EBUSY); } } else if (spa->spa_l2cache.sav_vdevs != NULL && nvlist_lookup_nvlist_array(spa->spa_l2cache.sav_config, ZPOOL_CONFIG_L2CACHE, &l2cache, &nl2cache) == 0 && (nv = spa_nvlist_lookup_by_guid(l2cache, nl2cache, guid)) != NULL) { char *nvstr = fnvlist_lookup_string(nv, ZPOOL_CONFIG_PATH); spa_history_log_internal(spa, "vdev remove", NULL, "%s vdev (%s) %s", spa_name(spa), VDEV_TYPE_L2CACHE, nvstr); /* * Cache devices can always be removed. */ vd = spa_lookup_by_guid(spa, guid, B_TRUE); ev = spa_event_create(spa, vd, NULL, ESC_ZFS_VDEV_REMOVE_AUX); spa_vdev_remove_aux(spa->spa_l2cache.sav_config, ZPOOL_CONFIG_L2CACHE, l2cache, nl2cache, nv); spa_load_l2cache(spa); spa->spa_l2cache.sav_sync = B_TRUE; } else if (vd != NULL && vd->vdev_islog) { ASSERT(!locked); error = spa_vdev_remove_log(vd, &txg); } else if (vd != NULL) { ASSERT(!locked); error = spa_vdev_remove_top(vd, &txg); } else { /* * There is no vdev of any kind with the specified guid. */ error = SET_ERROR(ENOENT); } if (!locked) error = spa_vdev_exit(spa, NULL, txg, error); if (ev != NULL) spa_event_post(ev); return (error); } int spa_removal_get_stats(spa_t *spa, pool_removal_stat_t *prs) { prs->prs_state = spa->spa_removing_phys.sr_state; if (prs->prs_state == DSS_NONE) return (SET_ERROR(ENOENT)); prs->prs_removing_vdev = spa->spa_removing_phys.sr_removing_vdev; prs->prs_start_time = spa->spa_removing_phys.sr_start_time; prs->prs_end_time = spa->spa_removing_phys.sr_end_time; prs->prs_to_copy = spa->spa_removing_phys.sr_to_copy; prs->prs_copied = spa->spa_removing_phys.sr_copied; if (spa->spa_vdev_removal != NULL) { for (int i = 0; i < TXG_SIZE; i++) { prs->prs_copied += spa->spa_vdev_removal->svr_bytes_done[i]; } } prs->prs_mapping_memory = 0; uint64_t indirect_vdev_id = spa->spa_removing_phys.sr_prev_indirect_vdev; while (indirect_vdev_id != -1) { vdev_t *vd = spa->spa_root_vdev->vdev_child[indirect_vdev_id]; vdev_indirect_config_t *vic = &vd->vdev_indirect_config; vdev_indirect_mapping_t *vim = vd->vdev_indirect_mapping; ASSERT3P(vd->vdev_ops, ==, &vdev_indirect_ops); prs->prs_mapping_memory += vdev_indirect_mapping_size(vim); indirect_vdev_id = vic->vic_prev_indirect_vdev; } return (0); } #if defined(_KERNEL) module_param(zfs_remove_max_segment, int, 0644); MODULE_PARM_DESC(zfs_remove_max_segment, "Largest contiguous segment to allocate when removing device"); module_param(vdev_removal_max_span, int, 0644); MODULE_PARM_DESC(vdev_removal_max_span, "Largest span of free chunks a remap segment can span"); /* BEGIN CSTYLED */ module_param(zfs_remove_max_bytes_pause, ulong, 0644); MODULE_PARM_DESC(zfs_remove_max_bytes_pause, "Pause device removal after this many bytes are copied " "(debug use only - causes removal to hang)"); /* END CSTYLED */ EXPORT_SYMBOL(free_from_removing_vdev); EXPORT_SYMBOL(spa_removal_get_stats); EXPORT_SYMBOL(spa_remove_init); EXPORT_SYMBOL(spa_restart_removal); EXPORT_SYMBOL(spa_vdev_removal_destroy); EXPORT_SYMBOL(spa_vdev_remove); EXPORT_SYMBOL(spa_vdev_remove_cancel); EXPORT_SYMBOL(spa_vdev_remove_suspend); EXPORT_SYMBOL(svr_sync); #endif