/* * 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 https://opensource.org/licenses/CDDL-1.0. * 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) 2018, Intel Corporation. * Copyright (c) 2020 by Lawrence Livermore National Security, LLC. * Copyright (c) 2022 Hewlett Packard Enterprise Development LP. * Copyright (c) 2024 by Delphix. All rights reserved. */ #include #include #include #include #include #include #include #include #include #include #include /* * This file contains the sequential reconstruction implementation for * resilvering. This form of resilvering is internally referred to as device * rebuild to avoid conflating it with the traditional healing reconstruction * performed by the dsl scan code. * * When replacing a device, or scrubbing the pool, ZFS has historically used * a process called resilvering which is a form of healing reconstruction. * This approach has the advantage that as blocks are read from disk their * checksums can be immediately verified and the data repaired. Unfortunately, * it also results in a random IO pattern to the disk even when extra care * is taken to sequentialize the IO as much as possible. This substantially * increases the time required to resilver the pool and restore redundancy. * * For mirrored devices it's possible to implement an alternate sequential * reconstruction strategy when resilvering. Sequential reconstruction * behaves like a traditional RAID rebuild and reconstructs a device in LBA * order without verifying the checksum. After this phase completes a second * scrub phase is started to verify all of the checksums. This two phase * process will take longer than the healing reconstruction described above. * However, it has that advantage that after the reconstruction first phase * completes redundancy has been restored. At this point the pool can incur * another device failure without risking data loss. * * There are a few noteworthy limitations and other advantages of resilvering * using sequential reconstruction vs healing reconstruction. * * Limitations: * * - Sequential reconstruction is not possible on RAIDZ due to its * variable stripe width. Note dRAID uses a fixed stripe width which * avoids this issue, but comes at the expense of some usable capacity. * * - Block checksums are not verified during sequential reconstruction. * Similar to traditional RAID the parity/mirror data is reconstructed * but cannot be immediately double checked. For this reason when the * last active resilver completes the pool is automatically scrubbed * by default. * * - Deferred resilvers using sequential reconstruction are not currently * supported. When adding another vdev to an active top-level resilver * it must be restarted. * * Advantages: * * - Sequential reconstruction is performed in LBA order which may be faster * than healing reconstruction particularly when using HDDs (or * especially with SMR devices). Only allocated capacity is resilvered. * * - Sequential reconstruction is not constrained by ZFS block boundaries. * This allows it to issue larger IOs to disk which span multiple blocks * allowing all of these logical blocks to be repaired with a single IO. * * - Unlike a healing resilver or scrub which are pool wide operations, * sequential reconstruction is handled by the top-level vdevs. This * allows for it to be started or canceled on a top-level vdev without * impacting any other top-level vdevs in the pool. * * - Data only referenced by a pool checkpoint will be repaired because * that space is reflected in the space maps. This differs for a * healing resilver or scrub which will not repair that data. */ /* * Size of rebuild reads; defaults to 1MiB per data disk and is capped at * SPA_MAXBLOCKSIZE. */ static uint64_t zfs_rebuild_max_segment = 1024 * 1024; /* * Maximum number of parallelly executed bytes per leaf vdev caused by a * sequential resilver. We attempt to strike a balance here between keeping * the vdev queues full of I/Os at all times and not overflowing the queues * to cause long latency, which would cause long txg sync times. * * A large default value can be safely used here because the default target * segment size is also large (zfs_rebuild_max_segment=1M). This helps keep * the queue depth short. * * 64MB was observed to deliver the best performance and set as the default. * Testing was performed with a 106-drive dRAID HDD pool (draid2:11d:106c) * and a rebuild rate of 1.2GB/s was measured to the distribute spare. * Smaller values were unable to fully saturate the available pool I/O. */ static uint64_t zfs_rebuild_vdev_limit = 64 << 20; /* * Automatically start a pool scrub when the last active sequential resilver * completes in order to verify the checksums of all blocks which have been * resilvered. This option is enabled by default and is strongly recommended. */ static int zfs_rebuild_scrub_enabled = 1; /* * For vdev_rebuild_initiate_sync() and vdev_rebuild_reset_sync(). */ static __attribute__((noreturn)) void vdev_rebuild_thread(void *arg); static void vdev_rebuild_reset_sync(void *arg, dmu_tx_t *tx); /* * Clear the per-vdev rebuild bytes value for a vdev tree. */ static void clear_rebuild_bytes(vdev_t *vd) { vdev_stat_t *vs = &vd->vdev_stat; for (uint64_t i = 0; i < vd->vdev_children; i++) clear_rebuild_bytes(vd->vdev_child[i]); mutex_enter(&vd->vdev_stat_lock); vs->vs_rebuild_processed = 0; mutex_exit(&vd->vdev_stat_lock); } /* * Determines whether a vdev_rebuild_thread() should be stopped. */ static boolean_t vdev_rebuild_should_stop(vdev_t *vd) { return (!vdev_writeable(vd) || vd->vdev_removing || vd->vdev_rebuild_exit_wanted || vd->vdev_rebuild_cancel_wanted || vd->vdev_rebuild_reset_wanted); } /* * Determine if the rebuild should be canceled. This may happen when all * vdevs with MISSING DTLs are detached. */ static boolean_t vdev_rebuild_should_cancel(vdev_t *vd) { vdev_rebuild_t *vr = &vd->vdev_rebuild_config; vdev_rebuild_phys_t *vrp = &vr->vr_rebuild_phys; if (!vdev_resilver_needed(vd, &vrp->vrp_min_txg, &vrp->vrp_max_txg)) return (B_TRUE); return (B_FALSE); } /* * The sync task for updating the on-disk state of a rebuild. This is * scheduled by vdev_rebuild_range(). */ static void vdev_rebuild_update_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_rebuild_t *vr = &vd->vdev_rebuild_config; vdev_rebuild_phys_t *vrp = &vr->vr_rebuild_phys; uint64_t txg = dmu_tx_get_txg(tx); mutex_enter(&vd->vdev_rebuild_lock); if (vr->vr_scan_offset[txg & TXG_MASK] > 0) { vrp->vrp_last_offset = vr->vr_scan_offset[txg & TXG_MASK]; vr->vr_scan_offset[txg & TXG_MASK] = 0; } vrp->vrp_scan_time_ms = vr->vr_prev_scan_time_ms + NSEC2MSEC(gethrtime() - vr->vr_pass_start_time); VERIFY0(zap_update(vd->vdev_spa->spa_meta_objset, vd->vdev_top_zap, VDEV_TOP_ZAP_VDEV_REBUILD_PHYS, sizeof (uint64_t), REBUILD_PHYS_ENTRIES, vrp, tx)); mutex_exit(&vd->vdev_rebuild_lock); } /* * Initialize the on-disk state for a new rebuild, start the rebuild thread. */ static void vdev_rebuild_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_rebuild_t *vr = &vd->vdev_rebuild_config; vdev_rebuild_phys_t *vrp = &vr->vr_rebuild_phys; ASSERT(vd->vdev_rebuilding); spa_feature_incr(vd->vdev_spa, SPA_FEATURE_DEVICE_REBUILD, tx); mutex_enter(&vd->vdev_rebuild_lock); memset(vrp, 0, sizeof (uint64_t) * REBUILD_PHYS_ENTRIES); vrp->vrp_rebuild_state = VDEV_REBUILD_ACTIVE; vrp->vrp_min_txg = 0; vrp->vrp_max_txg = dmu_tx_get_txg(tx); vrp->vrp_start_time = gethrestime_sec(); vrp->vrp_scan_time_ms = 0; vr->vr_prev_scan_time_ms = 0; /* * Rebuilds are currently only used when replacing a device, in which * case there must be DTL_MISSING entries. In the future, we could * allow rebuilds to be used in a way similar to a scrub. This would * be useful because it would allow us to rebuild the space used by * pool checkpoints. */ VERIFY(vdev_resilver_needed(vd, &vrp->vrp_min_txg, &vrp->vrp_max_txg)); VERIFY0(zap_update(vd->vdev_spa->spa_meta_objset, vd->vdev_top_zap, VDEV_TOP_ZAP_VDEV_REBUILD_PHYS, sizeof (uint64_t), REBUILD_PHYS_ENTRIES, vrp, tx)); spa_history_log_internal(spa, "rebuild", tx, "vdev_id=%llu vdev_guid=%llu started", (u_longlong_t)vd->vdev_id, (u_longlong_t)vd->vdev_guid); ASSERT3P(vd->vdev_rebuild_thread, ==, NULL); vd->vdev_rebuild_thread = thread_create(NULL, 0, vdev_rebuild_thread, vd, 0, &p0, TS_RUN, maxclsyspri); mutex_exit(&vd->vdev_rebuild_lock); } static void vdev_rebuild_log_notify(spa_t *spa, vdev_t *vd, const char *name) { nvlist_t *aux = fnvlist_alloc(); fnvlist_add_string(aux, ZFS_EV_RESILVER_TYPE, "sequential"); spa_event_notify(spa, vd, aux, name); nvlist_free(aux); } /* * Called to request that a new rebuild be started. The feature will remain * active for the duration of the rebuild, then revert to the enabled state. */ static void vdev_rebuild_initiate(vdev_t *vd) { spa_t *spa = vd->vdev_spa; ASSERT(vd->vdev_top == vd); ASSERT(MUTEX_HELD(&vd->vdev_rebuild_lock)); ASSERT(!vd->vdev_rebuilding); dmu_tx_t *tx = dmu_tx_create_dd(spa_get_dsl(spa)->dp_mos_dir); VERIFY0(dmu_tx_assign(tx, TXG_WAIT)); vd->vdev_rebuilding = B_TRUE; dsl_sync_task_nowait(spa_get_dsl(spa), vdev_rebuild_initiate_sync, (void *)(uintptr_t)vd->vdev_id, tx); dmu_tx_commit(tx); vdev_rebuild_log_notify(spa, vd, ESC_ZFS_RESILVER_START); } /* * Update the on-disk state to completed when a rebuild finishes. */ static void vdev_rebuild_complete_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_rebuild_t *vr = &vd->vdev_rebuild_config; vdev_rebuild_phys_t *vrp = &vr->vr_rebuild_phys; mutex_enter(&vd->vdev_rebuild_lock); /* * Handle a second device failure if it occurs after all rebuild I/O * has completed but before this sync task has been executed. */ if (vd->vdev_rebuild_reset_wanted) { mutex_exit(&vd->vdev_rebuild_lock); vdev_rebuild_reset_sync(arg, tx); return; } vrp->vrp_rebuild_state = VDEV_REBUILD_COMPLETE; vrp->vrp_end_time = gethrestime_sec(); VERIFY0(zap_update(vd->vdev_spa->spa_meta_objset, vd->vdev_top_zap, VDEV_TOP_ZAP_VDEV_REBUILD_PHYS, sizeof (uint64_t), REBUILD_PHYS_ENTRIES, vrp, tx)); vdev_dtl_reassess(vd, tx->tx_txg, vrp->vrp_max_txg, B_TRUE, B_TRUE); spa_feature_decr(vd->vdev_spa, SPA_FEATURE_DEVICE_REBUILD, tx); spa_history_log_internal(spa, "rebuild", tx, "vdev_id=%llu vdev_guid=%llu complete", (u_longlong_t)vd->vdev_id, (u_longlong_t)vd->vdev_guid); vdev_rebuild_log_notify(spa, vd, ESC_ZFS_RESILVER_FINISH); /* Handles detaching of spares */ spa_async_request(spa, SPA_ASYNC_REBUILD_DONE); vd->vdev_rebuilding = B_FALSE; mutex_exit(&vd->vdev_rebuild_lock); /* * While we're in syncing context take the opportunity to * setup the scrub when there are no more active rebuilds. */ setup_sync_arg_t setup_sync_arg = { .func = POOL_SCAN_SCRUB, .txgstart = 0, .txgend = 0, }; if (dsl_scan_setup_check(&setup_sync_arg.func, tx) == 0 && zfs_rebuild_scrub_enabled) { dsl_scan_setup_sync(&setup_sync_arg, tx); } cv_broadcast(&vd->vdev_rebuild_cv); /* Clear recent error events (i.e. duplicate events tracking) */ zfs_ereport_clear(spa, NULL); } /* * Update the on-disk state to canceled when a rebuild finishes. */ static void vdev_rebuild_cancel_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_rebuild_t *vr = &vd->vdev_rebuild_config; vdev_rebuild_phys_t *vrp = &vr->vr_rebuild_phys; mutex_enter(&vd->vdev_rebuild_lock); vrp->vrp_rebuild_state = VDEV_REBUILD_CANCELED; vrp->vrp_end_time = gethrestime_sec(); VERIFY0(zap_update(vd->vdev_spa->spa_meta_objset, vd->vdev_top_zap, VDEV_TOP_ZAP_VDEV_REBUILD_PHYS, sizeof (uint64_t), REBUILD_PHYS_ENTRIES, vrp, tx)); spa_feature_decr(vd->vdev_spa, SPA_FEATURE_DEVICE_REBUILD, tx); spa_history_log_internal(spa, "rebuild", tx, "vdev_id=%llu vdev_guid=%llu canceled", (u_longlong_t)vd->vdev_id, (u_longlong_t)vd->vdev_guid); vdev_rebuild_log_notify(spa, vd, ESC_ZFS_RESILVER_FINISH); vd->vdev_rebuild_cancel_wanted = B_FALSE; vd->vdev_rebuilding = B_FALSE; mutex_exit(&vd->vdev_rebuild_lock); spa_notify_waiters(spa); cv_broadcast(&vd->vdev_rebuild_cv); } /* * Resets the progress of a running rebuild. This will occur when a new * vdev is added to rebuild. */ static void vdev_rebuild_reset_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_rebuild_t *vr = &vd->vdev_rebuild_config; vdev_rebuild_phys_t *vrp = &vr->vr_rebuild_phys; mutex_enter(&vd->vdev_rebuild_lock); ASSERT(vrp->vrp_rebuild_state == VDEV_REBUILD_ACTIVE); ASSERT3P(vd->vdev_rebuild_thread, ==, NULL); vrp->vrp_last_offset = 0; vrp->vrp_min_txg = 0; vrp->vrp_max_txg = dmu_tx_get_txg(tx); vrp->vrp_bytes_scanned = 0; vrp->vrp_bytes_issued = 0; vrp->vrp_bytes_rebuilt = 0; vrp->vrp_bytes_est = 0; vrp->vrp_scan_time_ms = 0; vr->vr_prev_scan_time_ms = 0; /* See vdev_rebuild_initiate_sync comment */ VERIFY(vdev_resilver_needed(vd, &vrp->vrp_min_txg, &vrp->vrp_max_txg)); VERIFY0(zap_update(vd->vdev_spa->spa_meta_objset, vd->vdev_top_zap, VDEV_TOP_ZAP_VDEV_REBUILD_PHYS, sizeof (uint64_t), REBUILD_PHYS_ENTRIES, vrp, tx)); spa_history_log_internal(spa, "rebuild", tx, "vdev_id=%llu vdev_guid=%llu reset", (u_longlong_t)vd->vdev_id, (u_longlong_t)vd->vdev_guid); vd->vdev_rebuild_reset_wanted = B_FALSE; ASSERT(vd->vdev_rebuilding); vd->vdev_rebuild_thread = thread_create(NULL, 0, vdev_rebuild_thread, vd, 0, &p0, TS_RUN, maxclsyspri); mutex_exit(&vd->vdev_rebuild_lock); } /* * Clear the last rebuild status. */ void vdev_rebuild_clear_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_rebuild_t *vr = &vd->vdev_rebuild_config; vdev_rebuild_phys_t *vrp = &vr->vr_rebuild_phys; objset_t *mos = spa_meta_objset(spa); mutex_enter(&vd->vdev_rebuild_lock); if (!spa_feature_is_enabled(spa, SPA_FEATURE_DEVICE_REBUILD) || vrp->vrp_rebuild_state == VDEV_REBUILD_ACTIVE) { mutex_exit(&vd->vdev_rebuild_lock); return; } clear_rebuild_bytes(vd); memset(vrp, 0, sizeof (uint64_t) * REBUILD_PHYS_ENTRIES); if (vd->vdev_top_zap != 0 && zap_contains(mos, vd->vdev_top_zap, VDEV_TOP_ZAP_VDEV_REBUILD_PHYS) == 0) { VERIFY0(zap_update(mos, vd->vdev_top_zap, VDEV_TOP_ZAP_VDEV_REBUILD_PHYS, sizeof (uint64_t), REBUILD_PHYS_ENTRIES, vrp, tx)); } mutex_exit(&vd->vdev_rebuild_lock); } /* * The zio_done_func_t callback for each rebuild I/O issued. It's responsible * for updating the rebuild stats and limiting the number of in flight I/Os. */ static void vdev_rebuild_cb(zio_t *zio) { vdev_rebuild_t *vr = zio->io_private; vdev_rebuild_phys_t *vrp = &vr->vr_rebuild_phys; vdev_t *vd = vr->vr_top_vdev; mutex_enter(&vr->vr_io_lock); if (zio->io_error == ENXIO && !vdev_writeable(vd)) { /* * The I/O failed because the top-level vdev was unavailable. * Attempt to roll back to the last completed offset, in order * resume from the correct location if the pool is resumed. * (This works because spa_sync waits on spa_txg_zio before * it runs sync tasks.) */ uint64_t *off = &vr->vr_scan_offset[zio->io_txg & TXG_MASK]; *off = MIN(*off, zio->io_offset); } else if (zio->io_error) { vrp->vrp_errors++; } abd_free(zio->io_abd); ASSERT3U(vr->vr_bytes_inflight, >, 0); vr->vr_bytes_inflight -= zio->io_size; cv_broadcast(&vr->vr_io_cv); mutex_exit(&vr->vr_io_lock); spa_config_exit(vd->vdev_spa, SCL_STATE_ALL, vd); } /* * Initialize a block pointer that can be used to read the given segment * for sequential rebuild. */ static void vdev_rebuild_blkptr_init(blkptr_t *bp, vdev_t *vd, uint64_t start, uint64_t asize) { ASSERT(vd->vdev_ops == &vdev_draid_ops || vd->vdev_ops == &vdev_mirror_ops || vd->vdev_ops == &vdev_replacing_ops || vd->vdev_ops == &vdev_spare_ops); uint64_t psize = vd->vdev_ops == &vdev_draid_ops ? vdev_draid_asize_to_psize(vd, asize) : asize; BP_ZERO(bp); DVA_SET_VDEV(&bp->blk_dva[0], vd->vdev_id); DVA_SET_OFFSET(&bp->blk_dva[0], start); DVA_SET_GANG(&bp->blk_dva[0], 0); DVA_SET_ASIZE(&bp->blk_dva[0], asize); BP_SET_BIRTH(bp, TXG_INITIAL, TXG_INITIAL); BP_SET_LSIZE(bp, psize); BP_SET_PSIZE(bp, psize); 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); } /* * Issues a rebuild I/O and takes care of rate limiting the number of queued * rebuild I/Os. The provided start and size must be properly aligned for the * top-level vdev type being rebuilt. */ static int vdev_rebuild_range(vdev_rebuild_t *vr, uint64_t start, uint64_t size) { uint64_t ms_id __maybe_unused = vr->vr_scan_msp->ms_id; vdev_t *vd = vr->vr_top_vdev; spa_t *spa = vd->vdev_spa; blkptr_t blk; ASSERT3U(ms_id, ==, start >> vd->vdev_ms_shift); ASSERT3U(ms_id, ==, (start + size - 1) >> vd->vdev_ms_shift); vr->vr_pass_bytes_scanned += size; vr->vr_rebuild_phys.vrp_bytes_scanned += size; /* * Rebuild the data in this range by constructing a special block * pointer. It has no relation to any existing blocks in the pool. * However, by disabling checksum verification and issuing a scrub IO * we can reconstruct and repair any children with missing data. */ vdev_rebuild_blkptr_init(&blk, vd, start, size); uint64_t psize = BP_GET_PSIZE(&blk); if (!vdev_dtl_need_resilver(vd, &blk.blk_dva[0], psize, TXG_UNKNOWN)) { vr->vr_pass_bytes_skipped += size; return (0); } mutex_enter(&vr->vr_io_lock); /* Limit in flight rebuild I/Os */ while (vr->vr_bytes_inflight >= vr->vr_bytes_inflight_max) cv_wait(&vr->vr_io_cv, &vr->vr_io_lock); vr->vr_bytes_inflight += psize; mutex_exit(&vr->vr_io_lock); dmu_tx_t *tx = dmu_tx_create_dd(spa_get_dsl(spa)->dp_mos_dir); VERIFY0(dmu_tx_assign(tx, TXG_WAIT)); uint64_t txg = dmu_tx_get_txg(tx); spa_config_enter(spa, SCL_STATE_ALL, vd, RW_READER); mutex_enter(&vd->vdev_rebuild_lock); /* This is the first I/O for this txg. */ if (vr->vr_scan_offset[txg & TXG_MASK] == 0) { vr->vr_scan_offset[txg & TXG_MASK] = start; dsl_sync_task_nowait(spa_get_dsl(spa), vdev_rebuild_update_sync, (void *)(uintptr_t)vd->vdev_id, tx); } /* When exiting write out our progress. */ if (vdev_rebuild_should_stop(vd)) { mutex_enter(&vr->vr_io_lock); vr->vr_bytes_inflight -= psize; mutex_exit(&vr->vr_io_lock); spa_config_exit(vd->vdev_spa, SCL_STATE_ALL, vd); mutex_exit(&vd->vdev_rebuild_lock); dmu_tx_commit(tx); return (SET_ERROR(EINTR)); } mutex_exit(&vd->vdev_rebuild_lock); dmu_tx_commit(tx); vr->vr_scan_offset[txg & TXG_MASK] = start + size; vr->vr_pass_bytes_issued += size; vr->vr_rebuild_phys.vrp_bytes_issued += size; zio_nowait(zio_read(spa->spa_txg_zio[txg & TXG_MASK], spa, &blk, abd_alloc(psize, B_FALSE), psize, vdev_rebuild_cb, vr, ZIO_PRIORITY_REBUILD, ZIO_FLAG_RAW | ZIO_FLAG_CANFAIL | ZIO_FLAG_RESILVER, NULL)); return (0); } /* * Issues rebuild I/Os for all ranges in the provided vr->vr_tree range tree. */ static int vdev_rebuild_ranges(vdev_rebuild_t *vr) { vdev_t *vd = vr->vr_top_vdev; zfs_btree_t *t = &vr->vr_scan_tree->rt_root; zfs_btree_index_t idx; int error; for (range_seg_t *rs = zfs_btree_first(t, &idx); rs != NULL; rs = zfs_btree_next(t, &idx, &idx)) { uint64_t start = rs_get_start(rs, vr->vr_scan_tree); uint64_t size = rs_get_end(rs, vr->vr_scan_tree) - start; /* * zfs_scan_suspend_progress can be set to disable rebuild * progress for testing. See comment in dsl_scan_sync(). */ while (zfs_scan_suspend_progress && !vdev_rebuild_should_stop(vd)) { delay(hz); } while (size > 0) { uint64_t chunk_size; /* * Split range into legally-sized logical chunks * given the constraints of the top-level vdev * being rebuilt (dRAID or mirror). */ ASSERT3P(vd->vdev_ops, !=, NULL); chunk_size = vd->vdev_ops->vdev_op_rebuild_asize(vd, start, size, zfs_rebuild_max_segment); error = vdev_rebuild_range(vr, start, chunk_size); if (error != 0) return (error); size -= chunk_size; start += chunk_size; } } return (0); } /* * Calculates the estimated capacity which remains to be scanned. Since * we traverse the pool in metaslab order only allocated capacity beyond * the vrp_last_offset need be considered. All lower offsets must have * already been rebuilt and are thus already included in vrp_bytes_scanned. */ static void vdev_rebuild_update_bytes_est(vdev_t *vd, uint64_t ms_id) { vdev_rebuild_t *vr = &vd->vdev_rebuild_config; vdev_rebuild_phys_t *vrp = &vr->vr_rebuild_phys; uint64_t bytes_est = vrp->vrp_bytes_scanned; if (vrp->vrp_last_offset < vd->vdev_ms[ms_id]->ms_start) return; for (uint64_t i = ms_id; i < vd->vdev_ms_count; i++) { metaslab_t *msp = vd->vdev_ms[i]; mutex_enter(&msp->ms_lock); bytes_est += metaslab_allocated_space(msp); mutex_exit(&msp->ms_lock); } vrp->vrp_bytes_est = bytes_est; } /* * Load from disk the top-level vdev's rebuild information. */ int vdev_rebuild_load(vdev_t *vd) { vdev_rebuild_t *vr = &vd->vdev_rebuild_config; vdev_rebuild_phys_t *vrp = &vr->vr_rebuild_phys; spa_t *spa = vd->vdev_spa; int err = 0; mutex_enter(&vd->vdev_rebuild_lock); vd->vdev_rebuilding = B_FALSE; if (!spa_feature_is_enabled(spa, SPA_FEATURE_DEVICE_REBUILD)) { memset(vrp, 0, sizeof (uint64_t) * REBUILD_PHYS_ENTRIES); mutex_exit(&vd->vdev_rebuild_lock); return (SET_ERROR(ENOTSUP)); } ASSERT(vd->vdev_top == vd); err = zap_lookup(spa->spa_meta_objset, vd->vdev_top_zap, VDEV_TOP_ZAP_VDEV_REBUILD_PHYS, sizeof (uint64_t), REBUILD_PHYS_ENTRIES, vrp); /* * A missing or damaged VDEV_TOP_ZAP_VDEV_REBUILD_PHYS should * not prevent a pool from being imported. Clear the rebuild * status allowing a new resilver/rebuild to be started. */ if (err == ENOENT || err == EOVERFLOW || err == ECKSUM) { memset(vrp, 0, sizeof (uint64_t) * REBUILD_PHYS_ENTRIES); } else if (err) { mutex_exit(&vd->vdev_rebuild_lock); return (err); } vr->vr_prev_scan_time_ms = vrp->vrp_scan_time_ms; vr->vr_top_vdev = vd; mutex_exit(&vd->vdev_rebuild_lock); return (0); } /* * Each scan thread is responsible for rebuilding a top-level vdev. The * rebuild progress in tracked on-disk in VDEV_TOP_ZAP_VDEV_REBUILD_PHYS. */ static __attribute__((noreturn)) void vdev_rebuild_thread(void *arg) { vdev_t *vd = arg; spa_t *spa = vd->vdev_spa; vdev_t *rvd = spa->spa_root_vdev; int error = 0; /* * If there's a scrub in process request that it be stopped. This * is not required for a correct rebuild, but we do want rebuilds to * emulate the resilver behavior as much as possible. */ dsl_pool_t *dsl = spa_get_dsl(spa); if (dsl_scan_scrubbing(dsl)) dsl_scan_cancel(dsl); spa_config_enter(spa, SCL_CONFIG, FTAG, RW_READER); mutex_enter(&vd->vdev_rebuild_lock); ASSERT3P(vd->vdev_top, ==, vd); ASSERT3P(vd->vdev_rebuild_thread, !=, NULL); ASSERT(vd->vdev_rebuilding); ASSERT(spa_feature_is_active(spa, SPA_FEATURE_DEVICE_REBUILD)); ASSERT3B(vd->vdev_rebuild_cancel_wanted, ==, B_FALSE); vdev_rebuild_t *vr = &vd->vdev_rebuild_config; vdev_rebuild_phys_t *vrp = &vr->vr_rebuild_phys; vr->vr_top_vdev = vd; vr->vr_scan_msp = NULL; vr->vr_scan_tree = range_tree_create(NULL, RANGE_SEG64, NULL, 0, 0); mutex_init(&vr->vr_io_lock, NULL, MUTEX_DEFAULT, NULL); cv_init(&vr->vr_io_cv, NULL, CV_DEFAULT, NULL); vr->vr_pass_start_time = gethrtime(); vr->vr_pass_bytes_scanned = 0; vr->vr_pass_bytes_issued = 0; vr->vr_pass_bytes_skipped = 0; uint64_t update_est_time = gethrtime(); vdev_rebuild_update_bytes_est(vd, 0); clear_rebuild_bytes(vr->vr_top_vdev); mutex_exit(&vd->vdev_rebuild_lock); /* * Systematically walk the metaslabs and issue rebuild I/Os for * all ranges in the allocated space map. */ for (uint64_t i = 0; i < vd->vdev_ms_count; i++) { metaslab_t *msp = vd->vdev_ms[i]; vr->vr_scan_msp = msp; /* * Calculate the max number of in-flight bytes for top-level * vdev scanning operations (minimum 1MB, maximum 1/2 of * arc_c_max shared by all top-level vdevs). Limits for the * issuing phase are done per top-level vdev and are handled * separately. */ uint64_t limit = (arc_c_max / 2) / MAX(rvd->vdev_children, 1); vr->vr_bytes_inflight_max = MIN(limit, MAX(1ULL << 20, zfs_rebuild_vdev_limit * vd->vdev_children)); /* * Removal of vdevs from the vdev tree may eliminate the need * for the rebuild, in which case it should be canceled. The * vdev_rebuild_cancel_wanted flag is set until the sync task * completes. This may be after the rebuild thread exits. */ if (vdev_rebuild_should_cancel(vd)) { vd->vdev_rebuild_cancel_wanted = B_TRUE; error = EINTR; break; } ASSERT0(range_tree_space(vr->vr_scan_tree)); /* Disable any new allocations to this metaslab */ spa_config_exit(spa, SCL_CONFIG, FTAG); metaslab_disable(msp); mutex_enter(&msp->ms_sync_lock); mutex_enter(&msp->ms_lock); /* * If there are outstanding allocations wait for them to be * synced. This is needed to ensure all allocated ranges are * on disk and therefore will be rebuilt. */ for (int j = 0; j < TXG_SIZE; j++) { if (range_tree_space(msp->ms_allocating[j])) { mutex_exit(&msp->ms_lock); mutex_exit(&msp->ms_sync_lock); txg_wait_synced(dsl, 0); mutex_enter(&msp->ms_sync_lock); mutex_enter(&msp->ms_lock); break; } } /* * When a metaslab has been allocated from read its allocated * ranges from the space map object into the vr_scan_tree. * Then add inflight / unflushed ranges and remove inflight / * unflushed frees. This is the minimum range to be rebuilt. */ if (msp->ms_sm != NULL) { VERIFY0(space_map_load(msp->ms_sm, vr->vr_scan_tree, SM_ALLOC)); for (int i = 0; i < TXG_SIZE; i++) { ASSERT0(range_tree_space( msp->ms_allocating[i])); } range_tree_walk(msp->ms_unflushed_allocs, range_tree_add, vr->vr_scan_tree); range_tree_walk(msp->ms_unflushed_frees, range_tree_remove, vr->vr_scan_tree); /* * Remove ranges which have already been rebuilt based * on the last offset. This can happen when restarting * a scan after exporting and re-importing the pool. */ range_tree_clear(vr->vr_scan_tree, 0, vrp->vrp_last_offset); } mutex_exit(&msp->ms_lock); mutex_exit(&msp->ms_sync_lock); /* * To provide an accurate estimate re-calculate the estimated * size every 5 minutes to account for recent allocations and * frees made to space maps which have not yet been rebuilt. */ if (gethrtime() > update_est_time + SEC2NSEC(300)) { update_est_time = gethrtime(); vdev_rebuild_update_bytes_est(vd, i); } /* * Walk the allocated space map and issue the rebuild I/O. */ error = vdev_rebuild_ranges(vr); range_tree_vacate(vr->vr_scan_tree, NULL, NULL); spa_config_enter(spa, SCL_CONFIG, FTAG, RW_READER); metaslab_enable(msp, B_FALSE, B_FALSE); if (error != 0) break; } range_tree_destroy(vr->vr_scan_tree); spa_config_exit(spa, SCL_CONFIG, FTAG); /* Wait for any remaining rebuild I/O to complete */ mutex_enter(&vr->vr_io_lock); while (vr->vr_bytes_inflight > 0) cv_wait(&vr->vr_io_cv, &vr->vr_io_lock); mutex_exit(&vr->vr_io_lock); mutex_destroy(&vr->vr_io_lock); cv_destroy(&vr->vr_io_cv); spa_config_enter(spa, SCL_CONFIG, FTAG, RW_READER); dsl_pool_t *dp = spa_get_dsl(spa); dmu_tx_t *tx = dmu_tx_create_dd(dp->dp_mos_dir); VERIFY0(dmu_tx_assign(tx, TXG_WAIT)); mutex_enter(&vd->vdev_rebuild_lock); if (error == 0) { /* * After a successful rebuild clear the DTLs of all ranges * which were missing when the rebuild was started. These * ranges must have been rebuilt as a consequence of rebuilding * all allocated space. Note that unlike a scrub or resilver * the rebuild operation will reconstruct data only referenced * by a pool checkpoint. See the dsl_scan_done() comments. */ dsl_sync_task_nowait(dp, vdev_rebuild_complete_sync, (void *)(uintptr_t)vd->vdev_id, tx); } else if (vd->vdev_rebuild_cancel_wanted) { /* * The rebuild operation was canceled. This will occur when * a device participating in the rebuild is detached. */ dsl_sync_task_nowait(dp, vdev_rebuild_cancel_sync, (void *)(uintptr_t)vd->vdev_id, tx); } else if (vd->vdev_rebuild_reset_wanted) { /* * Reset the running rebuild without canceling and restarting * it. This will occur when a new device is attached and must * participate in the rebuild. */ dsl_sync_task_nowait(dp, vdev_rebuild_reset_sync, (void *)(uintptr_t)vd->vdev_id, tx); } else { /* * The rebuild operation should be suspended. This may occur * when detaching a child vdev or when exporting the pool. The * rebuild is left in the active state so it will be resumed. */ ASSERT(vrp->vrp_rebuild_state == VDEV_REBUILD_ACTIVE); vd->vdev_rebuilding = B_FALSE; } dmu_tx_commit(tx); vd->vdev_rebuild_thread = NULL; mutex_exit(&vd->vdev_rebuild_lock); spa_config_exit(spa, SCL_CONFIG, FTAG); cv_broadcast(&vd->vdev_rebuild_cv); thread_exit(); } /* * Returns B_TRUE if any top-level vdev are rebuilding. */ boolean_t vdev_rebuild_active(vdev_t *vd) { spa_t *spa = vd->vdev_spa; boolean_t ret = B_FALSE; if (vd == spa->spa_root_vdev) { for (uint64_t i = 0; i < vd->vdev_children; i++) { ret = vdev_rebuild_active(vd->vdev_child[i]); if (ret) return (ret); } } else if (vd->vdev_top_zap != 0) { vdev_rebuild_t *vr = &vd->vdev_rebuild_config; vdev_rebuild_phys_t *vrp = &vr->vr_rebuild_phys; mutex_enter(&vd->vdev_rebuild_lock); ret = (vrp->vrp_rebuild_state == VDEV_REBUILD_ACTIVE); mutex_exit(&vd->vdev_rebuild_lock); } return (ret); } /* * Start a rebuild operation. The rebuild may be restarted when the * top-level vdev is currently actively rebuilding. */ void vdev_rebuild(vdev_t *vd) { vdev_rebuild_t *vr = &vd->vdev_rebuild_config; vdev_rebuild_phys_t *vrp __maybe_unused = &vr->vr_rebuild_phys; ASSERT(vd->vdev_top == vd); ASSERT(vdev_is_concrete(vd)); ASSERT(!vd->vdev_removing); ASSERT(spa_feature_is_enabled(vd->vdev_spa, SPA_FEATURE_DEVICE_REBUILD)); mutex_enter(&vd->vdev_rebuild_lock); if (vd->vdev_rebuilding) { ASSERT3U(vrp->vrp_rebuild_state, ==, VDEV_REBUILD_ACTIVE); /* * Signal a running rebuild operation that it should restart * from the beginning because a new device was attached. The * vdev_rebuild_reset_wanted flag is set until the sync task * completes. This may be after the rebuild thread exits. */ if (!vd->vdev_rebuild_reset_wanted) vd->vdev_rebuild_reset_wanted = B_TRUE; } else { vdev_rebuild_initiate(vd); } mutex_exit(&vd->vdev_rebuild_lock); } static void vdev_rebuild_restart_impl(vdev_t *vd) { spa_t *spa = vd->vdev_spa; if (vd == spa->spa_root_vdev) { for (uint64_t i = 0; i < vd->vdev_children; i++) vdev_rebuild_restart_impl(vd->vdev_child[i]); } else if (vd->vdev_top_zap != 0) { vdev_rebuild_t *vr = &vd->vdev_rebuild_config; vdev_rebuild_phys_t *vrp = &vr->vr_rebuild_phys; mutex_enter(&vd->vdev_rebuild_lock); if (vrp->vrp_rebuild_state == VDEV_REBUILD_ACTIVE && vdev_writeable(vd) && !vd->vdev_rebuilding) { ASSERT(spa_feature_is_active(spa, SPA_FEATURE_DEVICE_REBUILD)); vd->vdev_rebuilding = B_TRUE; vd->vdev_rebuild_thread = thread_create(NULL, 0, vdev_rebuild_thread, vd, 0, &p0, TS_RUN, maxclsyspri); } mutex_exit(&vd->vdev_rebuild_lock); } } /* * Conditionally restart all of the vdev_rebuild_thread's for a pool. The * feature flag must be active and the rebuild in the active state. This * cannot be used to start a new rebuild. */ void vdev_rebuild_restart(spa_t *spa) { ASSERT(MUTEX_HELD(&spa_namespace_lock) || spa->spa_load_thread == curthread); vdev_rebuild_restart_impl(spa->spa_root_vdev); } /* * Stop and wait for all of the vdev_rebuild_thread's associated with the * vdev tree provide to be terminated (canceled or stopped). */ void vdev_rebuild_stop_wait(vdev_t *vd) { spa_t *spa = vd->vdev_spa; ASSERT(MUTEX_HELD(&spa_namespace_lock) || spa->spa_export_thread == curthread); if (vd == spa->spa_root_vdev) { for (uint64_t i = 0; i < vd->vdev_children; i++) vdev_rebuild_stop_wait(vd->vdev_child[i]); } else if (vd->vdev_top_zap != 0) { ASSERT(vd == vd->vdev_top); mutex_enter(&vd->vdev_rebuild_lock); if (vd->vdev_rebuild_thread != NULL) { vd->vdev_rebuild_exit_wanted = B_TRUE; while (vd->vdev_rebuilding) { cv_wait(&vd->vdev_rebuild_cv, &vd->vdev_rebuild_lock); } vd->vdev_rebuild_exit_wanted = B_FALSE; } mutex_exit(&vd->vdev_rebuild_lock); } } /* * Stop all rebuild operations but leave them in the active state so they * will be resumed when importing the pool. */ void vdev_rebuild_stop_all(spa_t *spa) { vdev_rebuild_stop_wait(spa->spa_root_vdev); } /* * Rebuild statistics reported per top-level vdev. */ int vdev_rebuild_get_stats(vdev_t *tvd, vdev_rebuild_stat_t *vrs) { spa_t *spa = tvd->vdev_spa; if (!spa_feature_is_enabled(spa, SPA_FEATURE_DEVICE_REBUILD)) return (SET_ERROR(ENOTSUP)); if (tvd != tvd->vdev_top || tvd->vdev_top_zap == 0) return (SET_ERROR(EINVAL)); int error = zap_contains(spa_meta_objset(spa), tvd->vdev_top_zap, VDEV_TOP_ZAP_VDEV_REBUILD_PHYS); if (error == ENOENT) { memset(vrs, 0, sizeof (vdev_rebuild_stat_t)); vrs->vrs_state = VDEV_REBUILD_NONE; error = 0; } else if (error == 0) { vdev_rebuild_t *vr = &tvd->vdev_rebuild_config; vdev_rebuild_phys_t *vrp = &vr->vr_rebuild_phys; mutex_enter(&tvd->vdev_rebuild_lock); vrs->vrs_state = vrp->vrp_rebuild_state; vrs->vrs_start_time = vrp->vrp_start_time; vrs->vrs_end_time = vrp->vrp_end_time; vrs->vrs_scan_time_ms = vrp->vrp_scan_time_ms; vrs->vrs_bytes_scanned = vrp->vrp_bytes_scanned; vrs->vrs_bytes_issued = vrp->vrp_bytes_issued; vrs->vrs_bytes_rebuilt = vrp->vrp_bytes_rebuilt; vrs->vrs_bytes_est = vrp->vrp_bytes_est; vrs->vrs_errors = vrp->vrp_errors; vrs->vrs_pass_time_ms = NSEC2MSEC(gethrtime() - vr->vr_pass_start_time); vrs->vrs_pass_bytes_scanned = vr->vr_pass_bytes_scanned; vrs->vrs_pass_bytes_issued = vr->vr_pass_bytes_issued; vrs->vrs_pass_bytes_skipped = vr->vr_pass_bytes_skipped; mutex_exit(&tvd->vdev_rebuild_lock); } return (error); } ZFS_MODULE_PARAM(zfs, zfs_, rebuild_max_segment, U64, ZMOD_RW, "Max segment size in bytes of rebuild reads"); ZFS_MODULE_PARAM(zfs, zfs_, rebuild_vdev_limit, U64, ZMOD_RW, "Max bytes in flight per leaf vdev for sequential resilvers"); ZFS_MODULE_PARAM(zfs, zfs_, rebuild_scrub_enabled, INT, ZMOD_RW, "Automatically scrub after sequential resilver completes");