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Diffstat (limited to 'module/zfs/metaslab.c')
| -rw-r--r-- | module/zfs/metaslab.c | 1049 |
1 files changed, 1049 insertions, 0 deletions
diff --git a/module/zfs/metaslab.c b/module/zfs/metaslab.c new file mode 100644 index 000000000..87727fac2 --- /dev/null +++ b/module/zfs/metaslab.c @@ -0,0 +1,1049 @@ +/* + * 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 2008 Sun Microsystems, Inc. All rights reserved. + * Use is subject to license terms. + */ + +#include <sys/zfs_context.h> +#include <sys/spa_impl.h> +#include <sys/dmu.h> +#include <sys/dmu_tx.h> +#include <sys/space_map.h> +#include <sys/metaslab_impl.h> +#include <sys/vdev_impl.h> +#include <sys/zio.h> + +uint64_t metaslab_aliquot = 512ULL << 10; +uint64_t metaslab_gang_bang = SPA_MAXBLOCKSIZE + 1; /* force gang blocks */ + +/* + * ========================================================================== + * Metaslab classes + * ========================================================================== + */ +metaslab_class_t * +metaslab_class_create(void) +{ + metaslab_class_t *mc; + + mc = kmem_zalloc(sizeof (metaslab_class_t), KM_SLEEP); + + mc->mc_rotor = NULL; + + return (mc); +} + +void +metaslab_class_destroy(metaslab_class_t *mc) +{ + metaslab_group_t *mg; + + while ((mg = mc->mc_rotor) != NULL) { + metaslab_class_remove(mc, mg); + metaslab_group_destroy(mg); + } + + kmem_free(mc, sizeof (metaslab_class_t)); +} + +void +metaslab_class_add(metaslab_class_t *mc, metaslab_group_t *mg) +{ + metaslab_group_t *mgprev, *mgnext; + + ASSERT(mg->mg_class == NULL); + + if ((mgprev = mc->mc_rotor) == NULL) { + mg->mg_prev = mg; + mg->mg_next = mg; + } else { + mgnext = mgprev->mg_next; + mg->mg_prev = mgprev; + mg->mg_next = mgnext; + mgprev->mg_next = mg; + mgnext->mg_prev = mg; + } + mc->mc_rotor = mg; + mg->mg_class = mc; +} + +void +metaslab_class_remove(metaslab_class_t *mc, metaslab_group_t *mg) +{ + metaslab_group_t *mgprev, *mgnext; + + ASSERT(mg->mg_class == mc); + + mgprev = mg->mg_prev; + mgnext = mg->mg_next; + + if (mg == mgnext) { + mc->mc_rotor = NULL; + } else { + mc->mc_rotor = mgnext; + mgprev->mg_next = mgnext; + mgnext->mg_prev = mgprev; + } + + mg->mg_prev = NULL; + mg->mg_next = NULL; + mg->mg_class = NULL; +} + +/* + * ========================================================================== + * Metaslab groups + * ========================================================================== + */ +static int +metaslab_compare(const void *x1, const void *x2) +{ + const metaslab_t *m1 = x1; + const metaslab_t *m2 = x2; + + if (m1->ms_weight < m2->ms_weight) + return (1); + if (m1->ms_weight > m2->ms_weight) + return (-1); + + /* + * If the weights are identical, use the offset to force uniqueness. + */ + if (m1->ms_map.sm_start < m2->ms_map.sm_start) + return (-1); + if (m1->ms_map.sm_start > m2->ms_map.sm_start) + return (1); + + ASSERT3P(m1, ==, m2); + + return (0); +} + +metaslab_group_t * +metaslab_group_create(metaslab_class_t *mc, vdev_t *vd) +{ + metaslab_group_t *mg; + + mg = kmem_zalloc(sizeof (metaslab_group_t), KM_SLEEP); + mutex_init(&mg->mg_lock, NULL, MUTEX_DEFAULT, NULL); + avl_create(&mg->mg_metaslab_tree, metaslab_compare, + sizeof (metaslab_t), offsetof(struct metaslab, ms_group_node)); + mg->mg_aliquot = metaslab_aliquot * MAX(1, vd->vdev_children); + mg->mg_vd = vd; + metaslab_class_add(mc, mg); + + return (mg); +} + +void +metaslab_group_destroy(metaslab_group_t *mg) +{ + avl_destroy(&mg->mg_metaslab_tree); + mutex_destroy(&mg->mg_lock); + kmem_free(mg, sizeof (metaslab_group_t)); +} + +static void +metaslab_group_add(metaslab_group_t *mg, metaslab_t *msp) +{ + mutex_enter(&mg->mg_lock); + ASSERT(msp->ms_group == NULL); + msp->ms_group = mg; + msp->ms_weight = 0; + avl_add(&mg->mg_metaslab_tree, msp); + mutex_exit(&mg->mg_lock); +} + +static void +metaslab_group_remove(metaslab_group_t *mg, metaslab_t *msp) +{ + mutex_enter(&mg->mg_lock); + ASSERT(msp->ms_group == mg); + avl_remove(&mg->mg_metaslab_tree, msp); + msp->ms_group = NULL; + mutex_exit(&mg->mg_lock); +} + +static void +metaslab_group_sort(metaslab_group_t *mg, metaslab_t *msp, uint64_t weight) +{ + /* + * Although in principle the weight can be any value, in + * practice we do not use values in the range [1, 510]. + */ + ASSERT(weight >= SPA_MINBLOCKSIZE-1 || weight == 0); + ASSERT(MUTEX_HELD(&msp->ms_lock)); + + mutex_enter(&mg->mg_lock); + ASSERT(msp->ms_group == mg); + avl_remove(&mg->mg_metaslab_tree, msp); + msp->ms_weight = weight; + avl_add(&mg->mg_metaslab_tree, msp); + mutex_exit(&mg->mg_lock); +} + +/* + * ========================================================================== + * The first-fit block allocator + * ========================================================================== + */ +static void +metaslab_ff_load(space_map_t *sm) +{ + ASSERT(sm->sm_ppd == NULL); + sm->sm_ppd = kmem_zalloc(64 * sizeof (uint64_t), KM_SLEEP); +} + +static void +metaslab_ff_unload(space_map_t *sm) +{ + kmem_free(sm->sm_ppd, 64 * sizeof (uint64_t)); + sm->sm_ppd = NULL; +} + +static uint64_t +metaslab_ff_alloc(space_map_t *sm, uint64_t size) +{ + avl_tree_t *t = &sm->sm_root; + uint64_t align = size & -size; + uint64_t *cursor = (uint64_t *)sm->sm_ppd + highbit(align) - 1; + space_seg_t *ss, ssearch; + avl_index_t where; + + ssearch.ss_start = *cursor; + ssearch.ss_end = *cursor + size; + + ss = avl_find(t, &ssearch, &where); + if (ss == NULL) + ss = avl_nearest(t, where, AVL_AFTER); + + while (ss != NULL) { + uint64_t offset = P2ROUNDUP(ss->ss_start, align); + + if (offset + size <= ss->ss_end) { + *cursor = offset + size; + return (offset); + } + ss = AVL_NEXT(t, ss); + } + + /* + * If we know we've searched the whole map (*cursor == 0), give up. + * Otherwise, reset the cursor to the beginning and try again. + */ + if (*cursor == 0) + return (-1ULL); + + *cursor = 0; + return (metaslab_ff_alloc(sm, size)); +} + +/* ARGSUSED */ +static void +metaslab_ff_claim(space_map_t *sm, uint64_t start, uint64_t size) +{ + /* No need to update cursor */ +} + +/* ARGSUSED */ +static void +metaslab_ff_free(space_map_t *sm, uint64_t start, uint64_t size) +{ + /* No need to update cursor */ +} + +static space_map_ops_t metaslab_ff_ops = { + metaslab_ff_load, + metaslab_ff_unload, + metaslab_ff_alloc, + metaslab_ff_claim, + metaslab_ff_free +}; + +/* + * ========================================================================== + * Metaslabs + * ========================================================================== + */ +metaslab_t * +metaslab_init(metaslab_group_t *mg, space_map_obj_t *smo, + uint64_t start, uint64_t size, uint64_t txg) +{ + vdev_t *vd = mg->mg_vd; + metaslab_t *msp; + + msp = kmem_zalloc(sizeof (metaslab_t), KM_SLEEP); + mutex_init(&msp->ms_lock, NULL, MUTEX_DEFAULT, NULL); + + msp->ms_smo_syncing = *smo; + + /* + * We create the main space map here, but we don't create the + * allocmaps and freemaps until metaslab_sync_done(). This serves + * two purposes: it allows metaslab_sync_done() to detect the + * addition of new space; and for debugging, it ensures that we'd + * data fault on any attempt to use this metaslab before it's ready. + */ + space_map_create(&msp->ms_map, start, size, + vd->vdev_ashift, &msp->ms_lock); + + metaslab_group_add(mg, msp); + + /* + * If we're opening an existing pool (txg == 0) or creating + * a new one (txg == TXG_INITIAL), all space is available now. + * If we're adding space to an existing pool, the new space + * does not become available until after this txg has synced. + */ + if (txg <= TXG_INITIAL) + metaslab_sync_done(msp, 0); + + if (txg != 0) { + /* + * The vdev is dirty, but the metaslab isn't -- it just needs + * to have metaslab_sync_done() invoked from vdev_sync_done(). + * [We could just dirty the metaslab, but that would cause us + * to allocate a space map object for it, which is wasteful + * and would mess up the locality logic in metaslab_weight().] + */ + ASSERT(TXG_CLEAN(txg) == spa_last_synced_txg(vd->vdev_spa)); + vdev_dirty(vd, 0, NULL, txg); + vdev_dirty(vd, VDD_METASLAB, msp, TXG_CLEAN(txg)); + } + + return (msp); +} + +void +metaslab_fini(metaslab_t *msp) +{ + metaslab_group_t *mg = msp->ms_group; + int t; + + vdev_space_update(mg->mg_vd, -msp->ms_map.sm_size, + -msp->ms_smo.smo_alloc, B_TRUE); + + metaslab_group_remove(mg, msp); + + mutex_enter(&msp->ms_lock); + + space_map_unload(&msp->ms_map); + space_map_destroy(&msp->ms_map); + + for (t = 0; t < TXG_SIZE; t++) { + space_map_destroy(&msp->ms_allocmap[t]); + space_map_destroy(&msp->ms_freemap[t]); + } + + mutex_exit(&msp->ms_lock); + mutex_destroy(&msp->ms_lock); + + kmem_free(msp, sizeof (metaslab_t)); +} + +#define METASLAB_WEIGHT_PRIMARY (1ULL << 63) +#define METASLAB_WEIGHT_SECONDARY (1ULL << 62) +#define METASLAB_ACTIVE_MASK \ + (METASLAB_WEIGHT_PRIMARY | METASLAB_WEIGHT_SECONDARY) +#define METASLAB_SMO_BONUS_MULTIPLIER 2 + +static uint64_t +metaslab_weight(metaslab_t *msp) +{ + metaslab_group_t *mg = msp->ms_group; + space_map_t *sm = &msp->ms_map; + space_map_obj_t *smo = &msp->ms_smo; + vdev_t *vd = mg->mg_vd; + uint64_t weight, space; + + ASSERT(MUTEX_HELD(&msp->ms_lock)); + + /* + * The baseline weight is the metaslab's free space. + */ + space = sm->sm_size - smo->smo_alloc; + weight = space; + + /* + * Modern disks have uniform bit density and constant angular velocity. + * Therefore, the outer recording zones are faster (higher bandwidth) + * than the inner zones by the ratio of outer to inner track diameter, + * which is typically around 2:1. We account for this by assigning + * higher weight to lower metaslabs (multiplier ranging from 2x to 1x). + * In effect, this means that we'll select the metaslab with the most + * free bandwidth rather than simply the one with the most free space. + */ + weight = 2 * weight - + ((sm->sm_start >> vd->vdev_ms_shift) * weight) / vd->vdev_ms_count; + ASSERT(weight >= space && weight <= 2 * space); + + /* + * For locality, assign higher weight to metaslabs we've used before. + */ + if (smo->smo_object != 0) + weight *= METASLAB_SMO_BONUS_MULTIPLIER; + ASSERT(weight >= space && + weight <= 2 * METASLAB_SMO_BONUS_MULTIPLIER * space); + + /* + * If this metaslab is one we're actively using, adjust its weight to + * make it preferable to any inactive metaslab so we'll polish it off. + */ + weight |= (msp->ms_weight & METASLAB_ACTIVE_MASK); + + return (weight); +} + +static int +metaslab_activate(metaslab_t *msp, uint64_t activation_weight) +{ + space_map_t *sm = &msp->ms_map; + + ASSERT(MUTEX_HELD(&msp->ms_lock)); + + if ((msp->ms_weight & METASLAB_ACTIVE_MASK) == 0) { + int error = space_map_load(sm, &metaslab_ff_ops, + SM_FREE, &msp->ms_smo, + msp->ms_group->mg_vd->vdev_spa->spa_meta_objset); + if (error) { + metaslab_group_sort(msp->ms_group, msp, 0); + return (error); + } + metaslab_group_sort(msp->ms_group, msp, + msp->ms_weight | activation_weight); + } + ASSERT(sm->sm_loaded); + ASSERT(msp->ms_weight & METASLAB_ACTIVE_MASK); + + return (0); +} + +static void +metaslab_passivate(metaslab_t *msp, uint64_t size) +{ + /* + * If size < SPA_MINBLOCKSIZE, then we will not allocate from + * this metaslab again. In that case, it had better be empty, + * or we would be leaving space on the table. + */ + ASSERT(size >= SPA_MINBLOCKSIZE || msp->ms_map.sm_space == 0); + metaslab_group_sort(msp->ms_group, msp, MIN(msp->ms_weight, size)); + ASSERT((msp->ms_weight & METASLAB_ACTIVE_MASK) == 0); +} + +/* + * Write a metaslab to disk in the context of the specified transaction group. + */ +void +metaslab_sync(metaslab_t *msp, uint64_t txg) +{ + vdev_t *vd = msp->ms_group->mg_vd; + spa_t *spa = vd->vdev_spa; + objset_t *mos = spa->spa_meta_objset; + space_map_t *allocmap = &msp->ms_allocmap[txg & TXG_MASK]; + space_map_t *freemap = &msp->ms_freemap[txg & TXG_MASK]; + space_map_t *freed_map = &msp->ms_freemap[TXG_CLEAN(txg) & TXG_MASK]; + space_map_t *sm = &msp->ms_map; + space_map_obj_t *smo = &msp->ms_smo_syncing; + dmu_buf_t *db; + dmu_tx_t *tx; + int t; + + tx = dmu_tx_create_assigned(spa_get_dsl(spa), txg); + + /* + * The only state that can actually be changing concurrently with + * metaslab_sync() is the metaslab's ms_map. No other thread can + * be modifying this txg's allocmap, freemap, freed_map, or smo. + * Therefore, we only hold ms_lock to satify space_map ASSERTs. + * We drop it whenever we call into the DMU, because the DMU + * can call down to us (e.g. via zio_free()) at any time. + */ + mutex_enter(&msp->ms_lock); + + if (smo->smo_object == 0) { + ASSERT(smo->smo_objsize == 0); + ASSERT(smo->smo_alloc == 0); + mutex_exit(&msp->ms_lock); + smo->smo_object = dmu_object_alloc(mos, + DMU_OT_SPACE_MAP, 1 << SPACE_MAP_BLOCKSHIFT, + DMU_OT_SPACE_MAP_HEADER, sizeof (*smo), tx); + ASSERT(smo->smo_object != 0); + dmu_write(mos, vd->vdev_ms_array, sizeof (uint64_t) * + (sm->sm_start >> vd->vdev_ms_shift), + sizeof (uint64_t), &smo->smo_object, tx); + mutex_enter(&msp->ms_lock); + } + + space_map_walk(freemap, space_map_add, freed_map); + + if (sm->sm_loaded && spa_sync_pass(spa) == 1 && smo->smo_objsize >= + 2 * sizeof (uint64_t) * avl_numnodes(&sm->sm_root)) { + /* + * The in-core space map representation is twice as compact + * as the on-disk one, so it's time to condense the latter + * by generating a pure allocmap from first principles. + * + * This metaslab is 100% allocated, + * minus the content of the in-core map (sm), + * minus what's been freed this txg (freed_map), + * minus allocations from txgs in the future + * (because they haven't been committed yet). + */ + space_map_vacate(allocmap, NULL, NULL); + space_map_vacate(freemap, NULL, NULL); + + space_map_add(allocmap, allocmap->sm_start, allocmap->sm_size); + + space_map_walk(sm, space_map_remove, allocmap); + space_map_walk(freed_map, space_map_remove, allocmap); + + for (t = 1; t < TXG_CONCURRENT_STATES; t++) + space_map_walk(&msp->ms_allocmap[(txg + t) & TXG_MASK], + space_map_remove, allocmap); + + mutex_exit(&msp->ms_lock); + space_map_truncate(smo, mos, tx); + mutex_enter(&msp->ms_lock); + } + + space_map_sync(allocmap, SM_ALLOC, smo, mos, tx); + space_map_sync(freemap, SM_FREE, smo, mos, tx); + + mutex_exit(&msp->ms_lock); + + VERIFY(0 == dmu_bonus_hold(mos, smo->smo_object, FTAG, &db)); + dmu_buf_will_dirty(db, tx); + ASSERT3U(db->db_size, >=, sizeof (*smo)); + bcopy(smo, db->db_data, sizeof (*smo)); + dmu_buf_rele(db, FTAG); + + dmu_tx_commit(tx); +} + +/* + * Called after a transaction group has completely synced to mark + * all of the metaslab's free space as usable. + */ +void +metaslab_sync_done(metaslab_t *msp, uint64_t txg) +{ + space_map_obj_t *smo = &msp->ms_smo; + space_map_obj_t *smosync = &msp->ms_smo_syncing; + space_map_t *sm = &msp->ms_map; + space_map_t *freed_map = &msp->ms_freemap[TXG_CLEAN(txg) & TXG_MASK]; + metaslab_group_t *mg = msp->ms_group; + vdev_t *vd = mg->mg_vd; + int t; + + mutex_enter(&msp->ms_lock); + + /* + * If this metaslab is just becoming available, initialize its + * allocmaps and freemaps and add its capacity to the vdev. + */ + if (freed_map->sm_size == 0) { + for (t = 0; t < TXG_SIZE; t++) { + space_map_create(&msp->ms_allocmap[t], sm->sm_start, + sm->sm_size, sm->sm_shift, sm->sm_lock); + space_map_create(&msp->ms_freemap[t], sm->sm_start, + sm->sm_size, sm->sm_shift, sm->sm_lock); + } + vdev_space_update(vd, sm->sm_size, 0, B_TRUE); + } + + vdev_space_update(vd, 0, smosync->smo_alloc - smo->smo_alloc, B_TRUE); + + ASSERT(msp->ms_allocmap[txg & TXG_MASK].sm_space == 0); + ASSERT(msp->ms_freemap[txg & TXG_MASK].sm_space == 0); + + /* + * If there's a space_map_load() in progress, wait for it to complete + * so that we have a consistent view of the in-core space map. + * Then, add everything we freed in this txg to the map. + */ + space_map_load_wait(sm); + space_map_vacate(freed_map, sm->sm_loaded ? space_map_free : NULL, sm); + + *smo = *smosync; + + /* + * If the map is loaded but no longer active, evict it as soon as all + * future allocations have synced. (If we unloaded it now and then + * loaded a moment later, the map wouldn't reflect those allocations.) + */ + if (sm->sm_loaded && (msp->ms_weight & METASLAB_ACTIVE_MASK) == 0) { + int evictable = 1; + + for (t = 1; t < TXG_CONCURRENT_STATES; t++) + if (msp->ms_allocmap[(txg + t) & TXG_MASK].sm_space) + evictable = 0; + + if (evictable) + space_map_unload(sm); + } + + metaslab_group_sort(mg, msp, metaslab_weight(msp)); + + mutex_exit(&msp->ms_lock); +} + +static uint64_t +metaslab_distance(metaslab_t *msp, dva_t *dva) +{ + uint64_t ms_shift = msp->ms_group->mg_vd->vdev_ms_shift; + uint64_t offset = DVA_GET_OFFSET(dva) >> ms_shift; + uint64_t start = msp->ms_map.sm_start >> ms_shift; + + if (msp->ms_group->mg_vd->vdev_id != DVA_GET_VDEV(dva)) + return (1ULL << 63); + + if (offset < start) + return ((start - offset) << ms_shift); + if (offset > start) + return ((offset - start) << ms_shift); + return (0); +} + +static uint64_t +metaslab_group_alloc(metaslab_group_t *mg, uint64_t size, uint64_t txg, + uint64_t min_distance, dva_t *dva, int d) +{ + metaslab_t *msp = NULL; + uint64_t offset = -1ULL; + avl_tree_t *t = &mg->mg_metaslab_tree; + uint64_t activation_weight; + uint64_t target_distance; + int i; + + activation_weight = METASLAB_WEIGHT_PRIMARY; + for (i = 0; i < d; i++) + if (DVA_GET_VDEV(&dva[i]) == mg->mg_vd->vdev_id) + activation_weight = METASLAB_WEIGHT_SECONDARY; + + for (;;) { + mutex_enter(&mg->mg_lock); + for (msp = avl_first(t); msp; msp = AVL_NEXT(t, msp)) { + if (msp->ms_weight < size) { + mutex_exit(&mg->mg_lock); + return (-1ULL); + } + + if (activation_weight == METASLAB_WEIGHT_PRIMARY) + break; + + target_distance = min_distance + + (msp->ms_smo.smo_alloc ? 0 : min_distance >> 1); + + for (i = 0; i < d; i++) + if (metaslab_distance(msp, &dva[i]) < + target_distance) + break; + if (i == d) + break; + } + mutex_exit(&mg->mg_lock); + if (msp == NULL) + return (-1ULL); + + mutex_enter(&msp->ms_lock); + + /* + * Ensure that the metaslab we have selected is still + * capable of handling our request. It's possible that + * another thread may have changed the weight while we + * were blocked on the metaslab lock. + */ + if (msp->ms_weight < size) { + mutex_exit(&msp->ms_lock); + continue; + } + + if ((msp->ms_weight & METASLAB_WEIGHT_SECONDARY) && + activation_weight == METASLAB_WEIGHT_PRIMARY) { + metaslab_passivate(msp, + msp->ms_weight & ~METASLAB_ACTIVE_MASK); + mutex_exit(&msp->ms_lock); + continue; + } + + if (metaslab_activate(msp, activation_weight) != 0) { + mutex_exit(&msp->ms_lock); + continue; + } + + if ((offset = space_map_alloc(&msp->ms_map, size)) != -1ULL) + break; + + metaslab_passivate(msp, size - 1); + + mutex_exit(&msp->ms_lock); + } + + if (msp->ms_allocmap[txg & TXG_MASK].sm_space == 0) + vdev_dirty(mg->mg_vd, VDD_METASLAB, msp, txg); + + space_map_add(&msp->ms_allocmap[txg & TXG_MASK], offset, size); + + mutex_exit(&msp->ms_lock); + + return (offset); +} + +/* + * Allocate a block for the specified i/o. + */ +static int +metaslab_alloc_dva(spa_t *spa, metaslab_class_t *mc, uint64_t psize, + dva_t *dva, int d, dva_t *hintdva, uint64_t txg, int flags) +{ + metaslab_group_t *mg, *rotor; + vdev_t *vd; + int dshift = 3; + int all_zero; + uint64_t offset = -1ULL; + uint64_t asize; + uint64_t distance; + + ASSERT(!DVA_IS_VALID(&dva[d])); + + /* + * For testing, make some blocks above a certain size be gang blocks. + */ + if (psize >= metaslab_gang_bang && (lbolt & 3) == 0) + return (ENOSPC); + + /* + * Start at the rotor and loop through all mgs until we find something. + * Note that there's no locking on mc_rotor or mc_allocated because + * nothing actually breaks if we miss a few updates -- we just won't + * allocate quite as evenly. It all balances out over time. + * + * If we are doing ditto or log blocks, try to spread them across + * consecutive vdevs. If we're forced to reuse a vdev before we've + * allocated all of our ditto blocks, then try and spread them out on + * that vdev as much as possible. If it turns out to not be possible, + * gradually lower our standards until anything becomes acceptable. + * Also, allocating on consecutive vdevs (as opposed to random vdevs) + * gives us hope of containing our fault domains to something we're + * able to reason about. Otherwise, any two top-level vdev failures + * will guarantee the loss of data. With consecutive allocation, + * only two adjacent top-level vdev failures will result in data loss. + * + * If we are doing gang blocks (hintdva is non-NULL), try to keep + * ourselves on the same vdev as our gang block header. That + * way, we can hope for locality in vdev_cache, plus it makes our + * fault domains something tractable. + */ + if (hintdva) { + vd = vdev_lookup_top(spa, DVA_GET_VDEV(&hintdva[d])); + if (flags & METASLAB_HINTBP_AVOID) + mg = vd->vdev_mg->mg_next; + else + mg = vd->vdev_mg; + } else if (d != 0) { + vd = vdev_lookup_top(spa, DVA_GET_VDEV(&dva[d - 1])); + mg = vd->vdev_mg->mg_next; + } else { + mg = mc->mc_rotor; + } + + /* + * If the hint put us into the wrong class, just follow the rotor. + */ + if (mg->mg_class != mc) + mg = mc->mc_rotor; + + rotor = mg; +top: + all_zero = B_TRUE; + do { + vd = mg->mg_vd; + /* + * Don't allocate from faulted devices. + */ + if (!vdev_allocatable(vd)) + goto next; + /* + * Avoid writing single-copy data to a failing vdev + */ + if ((vd->vdev_stat.vs_write_errors > 0 || + vd->vdev_state < VDEV_STATE_HEALTHY) && + d == 0 && dshift == 3) { + all_zero = B_FALSE; + goto next; + } + + ASSERT(mg->mg_class == mc); + + distance = vd->vdev_asize >> dshift; + if (distance <= (1ULL << vd->vdev_ms_shift)) + distance = 0; + else + all_zero = B_FALSE; + + asize = vdev_psize_to_asize(vd, psize); + ASSERT(P2PHASE(asize, 1ULL << vd->vdev_ashift) == 0); + + offset = metaslab_group_alloc(mg, asize, txg, distance, dva, d); + if (offset != -1ULL) { + /* + * If we've just selected this metaslab group, + * figure out whether the corresponding vdev is + * over- or under-used relative to the pool, + * and set an allocation bias to even it out. + */ + if (mc->mc_allocated == 0) { + vdev_stat_t *vs = &vd->vdev_stat; + uint64_t alloc, space; + int64_t vu, su; + + alloc = spa_get_alloc(spa); + space = spa_get_space(spa); + + /* + * Determine percent used in units of 0..1024. + * (This is just to avoid floating point.) + */ + vu = (vs->vs_alloc << 10) / (vs->vs_space + 1); + su = (alloc << 10) / (space + 1); + + /* + * Bias by at most +/- 25% of the aliquot. + */ + mg->mg_bias = ((su - vu) * + (int64_t)mg->mg_aliquot) / (1024 * 4); + } + + if (atomic_add_64_nv(&mc->mc_allocated, asize) >= + mg->mg_aliquot + mg->mg_bias) { + mc->mc_rotor = mg->mg_next; + mc->mc_allocated = 0; + } + + DVA_SET_VDEV(&dva[d], vd->vdev_id); + DVA_SET_OFFSET(&dva[d], offset); + DVA_SET_GANG(&dva[d], !!(flags & METASLAB_GANG_HEADER)); + DVA_SET_ASIZE(&dva[d], asize); + + return (0); + } +next: + mc->mc_rotor = mg->mg_next; + mc->mc_allocated = 0; + } while ((mg = mg->mg_next) != rotor); + + if (!all_zero) { + dshift++; + ASSERT(dshift < 64); + goto top; + } + + bzero(&dva[d], sizeof (dva_t)); + + return (ENOSPC); +} + +/* + * Free the block represented by DVA in the context of the specified + * transaction group. + */ +static void +metaslab_free_dva(spa_t *spa, const dva_t *dva, uint64_t txg, boolean_t now) +{ + uint64_t vdev = DVA_GET_VDEV(dva); + uint64_t offset = DVA_GET_OFFSET(dva); + uint64_t size = DVA_GET_ASIZE(dva); + vdev_t *vd; + metaslab_t *msp; + + ASSERT(DVA_IS_VALID(dva)); + + if (txg > spa_freeze_txg(spa)) + return; + + if ((vd = vdev_lookup_top(spa, vdev)) == NULL || + (offset >> vd->vdev_ms_shift) >= vd->vdev_ms_count) { + cmn_err(CE_WARN, "metaslab_free_dva(): bad DVA %llu:%llu", + (u_longlong_t)vdev, (u_longlong_t)offset); + ASSERT(0); + return; + } + + msp = vd->vdev_ms[offset >> vd->vdev_ms_shift]; + + if (DVA_GET_GANG(dva)) + size = vdev_psize_to_asize(vd, SPA_GANGBLOCKSIZE); + + mutex_enter(&msp->ms_lock); + + if (now) { + space_map_remove(&msp->ms_allocmap[txg & TXG_MASK], + offset, size); + space_map_free(&msp->ms_map, offset, size); + } else { + if (msp->ms_freemap[txg & TXG_MASK].sm_space == 0) + vdev_dirty(vd, VDD_METASLAB, msp, txg); + space_map_add(&msp->ms_freemap[txg & TXG_MASK], offset, size); + } + + mutex_exit(&msp->ms_lock); +} + +/* + * Intent log support: upon opening the pool after a crash, notify the SPA + * of blocks that the intent log has allocated for immediate write, but + * which are still considered free by the SPA because the last transaction + * group didn't commit yet. + */ +static int +metaslab_claim_dva(spa_t *spa, const dva_t *dva, uint64_t txg) +{ + uint64_t vdev = DVA_GET_VDEV(dva); + uint64_t offset = DVA_GET_OFFSET(dva); + uint64_t size = DVA_GET_ASIZE(dva); + vdev_t *vd; + metaslab_t *msp; + int error; + + ASSERT(DVA_IS_VALID(dva)); + + if ((vd = vdev_lookup_top(spa, vdev)) == NULL || + (offset >> vd->vdev_ms_shift) >= vd->vdev_ms_count) + return (ENXIO); + + msp = vd->vdev_ms[offset >> vd->vdev_ms_shift]; + + if (DVA_GET_GANG(dva)) + size = vdev_psize_to_asize(vd, SPA_GANGBLOCKSIZE); + + mutex_enter(&msp->ms_lock); + + error = metaslab_activate(msp, METASLAB_WEIGHT_SECONDARY); + if (error || txg == 0) { /* txg == 0 indicates dry run */ + mutex_exit(&msp->ms_lock); + return (error); + } + + space_map_claim(&msp->ms_map, offset, size); + + if (spa_mode & FWRITE) { /* don't dirty if we're zdb(1M) */ + if (msp->ms_allocmap[txg & TXG_MASK].sm_space == 0) + vdev_dirty(vd, VDD_METASLAB, msp, txg); + space_map_add(&msp->ms_allocmap[txg & TXG_MASK], offset, size); + } + + mutex_exit(&msp->ms_lock); + + return (0); +} + +int +metaslab_alloc(spa_t *spa, metaslab_class_t *mc, uint64_t psize, blkptr_t *bp, + int ndvas, uint64_t txg, blkptr_t *hintbp, int flags) +{ + dva_t *dva = bp->blk_dva; + dva_t *hintdva = hintbp->blk_dva; + int error = 0; + + ASSERT(bp->blk_birth == 0); + + spa_config_enter(spa, SCL_ALLOC, FTAG, RW_READER); + + if (mc->mc_rotor == NULL) { /* no vdevs in this class */ + spa_config_exit(spa, SCL_ALLOC, FTAG); + return (ENOSPC); + } + + ASSERT(ndvas > 0 && ndvas <= spa_max_replication(spa)); + ASSERT(BP_GET_NDVAS(bp) == 0); + ASSERT(hintbp == NULL || ndvas <= BP_GET_NDVAS(hintbp)); + + for (int d = 0; d < ndvas; d++) { + error = metaslab_alloc_dva(spa, mc, psize, dva, d, hintdva, + txg, flags); + if (error) { + for (d--; d >= 0; d--) { + metaslab_free_dva(spa, &dva[d], txg, B_TRUE); + bzero(&dva[d], sizeof (dva_t)); + } + spa_config_exit(spa, SCL_ALLOC, FTAG); + return (error); + } + } + ASSERT(error == 0); + ASSERT(BP_GET_NDVAS(bp) == ndvas); + + spa_config_exit(spa, SCL_ALLOC, FTAG); + + bp->blk_birth = txg; + + return (0); +} + +void +metaslab_free(spa_t *spa, const blkptr_t *bp, uint64_t txg, boolean_t now) +{ + const dva_t *dva = bp->blk_dva; + int ndvas = BP_GET_NDVAS(bp); + + ASSERT(!BP_IS_HOLE(bp)); + ASSERT(!now || bp->blk_birth >= spa->spa_syncing_txg); + + spa_config_enter(spa, SCL_FREE, FTAG, RW_READER); + + for (int d = 0; d < ndvas; d++) + metaslab_free_dva(spa, &dva[d], txg, now); + + spa_config_exit(spa, SCL_FREE, FTAG); +} + +int +metaslab_claim(spa_t *spa, const blkptr_t *bp, uint64_t txg) +{ + const dva_t *dva = bp->blk_dva; + int ndvas = BP_GET_NDVAS(bp); + int error = 0; + + ASSERT(!BP_IS_HOLE(bp)); + + if (txg != 0) { + /* + * First do a dry run to make sure all DVAs are claimable, + * so we don't have to unwind from partial failures below. + */ + if ((error = metaslab_claim(spa, bp, 0)) != 0) + return (error); + } + + spa_config_enter(spa, SCL_ALLOC, FTAG, RW_READER); + + for (int d = 0; d < ndvas; d++) + if ((error = metaslab_claim_dva(spa, &dva[d], txg)) != 0) + break; + + spa_config_exit(spa, SCL_ALLOC, FTAG); + + ASSERT(error == 0 || txg == 0); + + return (error); +} |