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-rw-r--r--uts/common/fs/zfs/metaslab.c1604
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diff --git a/uts/common/fs/zfs/metaslab.c b/uts/common/fs/zfs/metaslab.c
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+/*
+ * 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.
+ */
+
+#include <sys/zfs_context.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 debugging: when set, keeps all space maps in core to verify frees.
+ */
+static int metaslab_debug = 0;
+
+/*
+ * Minimum size which forces the dynamic allocator to change
+ * it's allocation strategy. Once the space map cannot satisfy
+ * an allocation of this size then it switches to using more
+ * aggressive strategy (i.e search by size rather than offset).
+ */
+uint64_t metaslab_df_alloc_threshold = SPA_MAXBLOCKSIZE;
+
+/*
+ * The minimum free space, in percent, which must be available
+ * in a space map to continue allocations in a first-fit fashion.
+ * Once the space_map's free space drops below this level we dynamically
+ * switch to using best-fit allocations.
+ */
+int metaslab_df_free_pct = 4;
+
+/*
+ * A metaslab is considered "free" if it contains a contiguous
+ * segment which is greater than metaslab_min_alloc_size.
+ */
+uint64_t metaslab_min_alloc_size = DMU_MAX_ACCESS;
+
+/*
+ * Max number of space_maps to prefetch.
+ */
+int metaslab_prefetch_limit = SPA_DVAS_PER_BP;
+
+/*
+ * Percentage bonus multiplier for metaslabs that are in the bonus area.
+ */
+int metaslab_smo_bonus_pct = 150;
+
+/*
+ * ==========================================================================
+ * Metaslab classes
+ * ==========================================================================
+ */
+metaslab_class_t *
+metaslab_class_create(spa_t *spa, space_map_ops_t *ops)
+{
+ metaslab_class_t *mc;
+
+ mc = kmem_zalloc(sizeof (metaslab_class_t), KM_SLEEP);
+
+ mc->mc_spa = spa;
+ mc->mc_rotor = NULL;
+ mc->mc_ops = ops;
+
+ return (mc);
+}
+
+void
+metaslab_class_destroy(metaslab_class_t *mc)
+{
+ ASSERT(mc->mc_rotor == NULL);
+ ASSERT(mc->mc_alloc == 0);
+ ASSERT(mc->mc_deferred == 0);
+ ASSERT(mc->mc_space == 0);
+ ASSERT(mc->mc_dspace == 0);
+
+ kmem_free(mc, sizeof (metaslab_class_t));
+}
+
+int
+metaslab_class_validate(metaslab_class_t *mc)
+{
+ metaslab_group_t *mg;
+ vdev_t *vd;
+
+ /*
+ * Must hold one of the spa_config locks.
+ */
+ ASSERT(spa_config_held(mc->mc_spa, SCL_ALL, RW_READER) ||
+ spa_config_held(mc->mc_spa, SCL_ALL, RW_WRITER));
+
+ if ((mg = mc->mc_rotor) == NULL)
+ return (0);
+
+ do {
+ vd = mg->mg_vd;
+ ASSERT(vd->vdev_mg != NULL);
+ ASSERT3P(vd->vdev_top, ==, vd);
+ ASSERT3P(mg->mg_class, ==, mc);
+ ASSERT3P(vd->vdev_ops, !=, &vdev_hole_ops);
+ } while ((mg = mg->mg_next) != mc->mc_rotor);
+
+ return (0);
+}
+
+void
+metaslab_class_space_update(metaslab_class_t *mc, int64_t alloc_delta,
+ int64_t defer_delta, int64_t space_delta, int64_t dspace_delta)
+{
+ atomic_add_64(&mc->mc_alloc, alloc_delta);
+ atomic_add_64(&mc->mc_deferred, defer_delta);
+ atomic_add_64(&mc->mc_space, space_delta);
+ atomic_add_64(&mc->mc_dspace, dspace_delta);
+}
+
+uint64_t
+metaslab_class_get_alloc(metaslab_class_t *mc)
+{
+ return (mc->mc_alloc);
+}
+
+uint64_t
+metaslab_class_get_deferred(metaslab_class_t *mc)
+{
+ return (mc->mc_deferred);
+}
+
+uint64_t
+metaslab_class_get_space(metaslab_class_t *mc)
+{
+ return (mc->mc_space);
+}
+
+uint64_t
+metaslab_class_get_dspace(metaslab_class_t *mc)
+{
+ return (spa_deflate(mc->mc_spa) ? mc->mc_dspace : mc->mc_space);
+}
+
+/*
+ * ==========================================================================
+ * 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_vd = vd;
+ mg->mg_class = mc;
+ mg->mg_activation_count = 0;
+
+ return (mg);
+}
+
+void
+metaslab_group_destroy(metaslab_group_t *mg)
+{
+ ASSERT(mg->mg_prev == NULL);
+ ASSERT(mg->mg_next == NULL);
+ /*
+ * We may have gone below zero with the activation count
+ * either because we never activated in the first place or
+ * because we're done, and possibly removing the vdev.
+ */
+ ASSERT(mg->mg_activation_count <= 0);
+
+ avl_destroy(&mg->mg_metaslab_tree);
+ mutex_destroy(&mg->mg_lock);
+ kmem_free(mg, sizeof (metaslab_group_t));
+}
+
+void
+metaslab_group_activate(metaslab_group_t *mg)
+{
+ metaslab_class_t *mc = mg->mg_class;
+ metaslab_group_t *mgprev, *mgnext;
+
+ ASSERT(spa_config_held(mc->mc_spa, SCL_ALLOC, RW_WRITER));
+
+ ASSERT(mc->mc_rotor != mg);
+ ASSERT(mg->mg_prev == NULL);
+ ASSERT(mg->mg_next == NULL);
+ ASSERT(mg->mg_activation_count <= 0);
+
+ if (++mg->mg_activation_count <= 0)
+ return;
+
+ mg->mg_aliquot = metaslab_aliquot * MAX(1, mg->mg_vd->vdev_children);
+
+ 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;
+}
+
+void
+metaslab_group_passivate(metaslab_group_t *mg)
+{
+ metaslab_class_t *mc = mg->mg_class;
+ metaslab_group_t *mgprev, *mgnext;
+
+ ASSERT(spa_config_held(mc->mc_spa, SCL_ALLOC, RW_WRITER));
+
+ if (--mg->mg_activation_count != 0) {
+ ASSERT(mc->mc_rotor != mg);
+ ASSERT(mg->mg_prev == NULL);
+ ASSERT(mg->mg_next == NULL);
+ ASSERT(mg->mg_activation_count < 0);
+ return;
+ }
+
+ 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;
+}
+
+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);
+}
+
+/*
+ * ==========================================================================
+ * Common allocator routines
+ * ==========================================================================
+ */
+static int
+metaslab_segsize_compare(const void *x1, const void *x2)
+{
+ const space_seg_t *s1 = x1;
+ const space_seg_t *s2 = x2;
+ uint64_t ss_size1 = s1->ss_end - s1->ss_start;
+ uint64_t ss_size2 = s2->ss_end - s2->ss_start;
+
+ if (ss_size1 < ss_size2)
+ return (-1);
+ if (ss_size1 > ss_size2)
+ return (1);
+
+ if (s1->ss_start < s2->ss_start)
+ return (-1);
+ if (s1->ss_start > s2->ss_start)
+ return (1);
+
+ return (0);
+}
+
+/*
+ * This is a helper function that can be used by the allocator to find
+ * a suitable block to allocate. This will search the specified AVL
+ * tree looking for a block that matches the specified criteria.
+ */
+static uint64_t
+metaslab_block_picker(avl_tree_t *t, uint64_t *cursor, uint64_t size,
+ uint64_t align)
+{
+ 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_block_picker(t, cursor, size, align));
+}
+
+static void
+metaslab_pp_load(space_map_t *sm)
+{
+ space_seg_t *ss;
+
+ ASSERT(sm->sm_ppd == NULL);
+ sm->sm_ppd = kmem_zalloc(64 * sizeof (uint64_t), KM_SLEEP);
+
+ sm->sm_pp_root = kmem_alloc(sizeof (avl_tree_t), KM_SLEEP);
+ avl_create(sm->sm_pp_root, metaslab_segsize_compare,
+ sizeof (space_seg_t), offsetof(struct space_seg, ss_pp_node));
+
+ for (ss = avl_first(&sm->sm_root); ss; ss = AVL_NEXT(&sm->sm_root, ss))
+ avl_add(sm->sm_pp_root, ss);
+}
+
+static void
+metaslab_pp_unload(space_map_t *sm)
+{
+ void *cookie = NULL;
+
+ kmem_free(sm->sm_ppd, 64 * sizeof (uint64_t));
+ sm->sm_ppd = NULL;
+
+ while (avl_destroy_nodes(sm->sm_pp_root, &cookie) != NULL) {
+ /* tear down the tree */
+ }
+
+ avl_destroy(sm->sm_pp_root);
+ kmem_free(sm->sm_pp_root, sizeof (avl_tree_t));
+ sm->sm_pp_root = NULL;
+}
+
+/* ARGSUSED */
+static void
+metaslab_pp_claim(space_map_t *sm, uint64_t start, uint64_t size)
+{
+ /* No need to update cursor */
+}
+
+/* ARGSUSED */
+static void
+metaslab_pp_free(space_map_t *sm, uint64_t start, uint64_t size)
+{
+ /* No need to update cursor */
+}
+
+/*
+ * Return the maximum contiguous segment within the metaslab.
+ */
+uint64_t
+metaslab_pp_maxsize(space_map_t *sm)
+{
+ avl_tree_t *t = sm->sm_pp_root;
+ space_seg_t *ss;
+
+ if (t == NULL || (ss = avl_last(t)) == NULL)
+ return (0ULL);
+
+ return (ss->ss_end - ss->ss_start);
+}
+
+/*
+ * ==========================================================================
+ * The first-fit block allocator
+ * ==========================================================================
+ */
+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;
+
+ return (metaslab_block_picker(t, cursor, size, align));
+}
+
+/* ARGSUSED */
+boolean_t
+metaslab_ff_fragmented(space_map_t *sm)
+{
+ return (B_TRUE);
+}
+
+static space_map_ops_t metaslab_ff_ops = {
+ metaslab_pp_load,
+ metaslab_pp_unload,
+ metaslab_ff_alloc,
+ metaslab_pp_claim,
+ metaslab_pp_free,
+ metaslab_pp_maxsize,
+ metaslab_ff_fragmented
+};
+
+/*
+ * ==========================================================================
+ * Dynamic block allocator -
+ * Uses the first fit allocation scheme until space get low and then
+ * adjusts to a best fit allocation method. Uses metaslab_df_alloc_threshold
+ * and metaslab_df_free_pct to determine when to switch the allocation scheme.
+ * ==========================================================================
+ */
+static uint64_t
+metaslab_df_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;
+ uint64_t max_size = metaslab_pp_maxsize(sm);
+ int free_pct = sm->sm_space * 100 / sm->sm_size;
+
+ ASSERT(MUTEX_HELD(sm->sm_lock));
+ ASSERT3U(avl_numnodes(&sm->sm_root), ==, avl_numnodes(sm->sm_pp_root));
+
+ if (max_size < size)
+ return (-1ULL);
+
+ /*
+ * If we're running low on space switch to using the size
+ * sorted AVL tree (best-fit).
+ */
+ if (max_size < metaslab_df_alloc_threshold ||
+ free_pct < metaslab_df_free_pct) {
+ t = sm->sm_pp_root;
+ *cursor = 0;
+ }
+
+ return (metaslab_block_picker(t, cursor, size, 1ULL));
+}
+
+static boolean_t
+metaslab_df_fragmented(space_map_t *sm)
+{
+ uint64_t max_size = metaslab_pp_maxsize(sm);
+ int free_pct = sm->sm_space * 100 / sm->sm_size;
+
+ if (max_size >= metaslab_df_alloc_threshold &&
+ free_pct >= metaslab_df_free_pct)
+ return (B_FALSE);
+
+ return (B_TRUE);
+}
+
+static space_map_ops_t metaslab_df_ops = {
+ metaslab_pp_load,
+ metaslab_pp_unload,
+ metaslab_df_alloc,
+ metaslab_pp_claim,
+ metaslab_pp_free,
+ metaslab_pp_maxsize,
+ metaslab_df_fragmented
+};
+
+/*
+ * ==========================================================================
+ * Other experimental allocators
+ * ==========================================================================
+ */
+static uint64_t
+metaslab_cdf_alloc(space_map_t *sm, uint64_t size)
+{
+ avl_tree_t *t = &sm->sm_root;
+ uint64_t *cursor = (uint64_t *)sm->sm_ppd;
+ uint64_t *extent_end = (uint64_t *)sm->sm_ppd + 1;
+ uint64_t max_size = metaslab_pp_maxsize(sm);
+ uint64_t rsize = size;
+ uint64_t offset = 0;
+
+ ASSERT(MUTEX_HELD(sm->sm_lock));
+ ASSERT3U(avl_numnodes(&sm->sm_root), ==, avl_numnodes(sm->sm_pp_root));
+
+ if (max_size < size)
+ return (-1ULL);
+
+ ASSERT3U(*extent_end, >=, *cursor);
+
+ /*
+ * If we're running low on space switch to using the size
+ * sorted AVL tree (best-fit).
+ */
+ if ((*cursor + size) > *extent_end) {
+
+ t = sm->sm_pp_root;
+ *cursor = *extent_end = 0;
+
+ if (max_size > 2 * SPA_MAXBLOCKSIZE)
+ rsize = MIN(metaslab_min_alloc_size, max_size);
+ offset = metaslab_block_picker(t, extent_end, rsize, 1ULL);
+ if (offset != -1)
+ *cursor = offset + size;
+ } else {
+ offset = metaslab_block_picker(t, cursor, rsize, 1ULL);
+ }
+ ASSERT3U(*cursor, <=, *extent_end);
+ return (offset);
+}
+
+static boolean_t
+metaslab_cdf_fragmented(space_map_t *sm)
+{
+ uint64_t max_size = metaslab_pp_maxsize(sm);
+
+ if (max_size > (metaslab_min_alloc_size * 10))
+ return (B_FALSE);
+ return (B_TRUE);
+}
+
+static space_map_ops_t metaslab_cdf_ops = {
+ metaslab_pp_load,
+ metaslab_pp_unload,
+ metaslab_cdf_alloc,
+ metaslab_pp_claim,
+ metaslab_pp_free,
+ metaslab_pp_maxsize,
+ metaslab_cdf_fragmented
+};
+
+uint64_t metaslab_ndf_clump_shift = 4;
+
+static uint64_t
+metaslab_ndf_alloc(space_map_t *sm, uint64_t size)
+{
+ avl_tree_t *t = &sm->sm_root;
+ avl_index_t where;
+ space_seg_t *ss, ssearch;
+ uint64_t hbit = highbit(size);
+ uint64_t *cursor = (uint64_t *)sm->sm_ppd + hbit - 1;
+ uint64_t max_size = metaslab_pp_maxsize(sm);
+
+ ASSERT(MUTEX_HELD(sm->sm_lock));
+ ASSERT3U(avl_numnodes(&sm->sm_root), ==, avl_numnodes(sm->sm_pp_root));
+
+ if (max_size < size)
+ return (-1ULL);
+
+ ssearch.ss_start = *cursor;
+ ssearch.ss_end = *cursor + size;
+
+ ss = avl_find(t, &ssearch, &where);
+ if (ss == NULL || (ss->ss_start + size > ss->ss_end)) {
+ t = sm->sm_pp_root;
+
+ ssearch.ss_start = 0;
+ ssearch.ss_end = MIN(max_size,
+ 1ULL << (hbit + metaslab_ndf_clump_shift));
+ ss = avl_find(t, &ssearch, &where);
+ if (ss == NULL)
+ ss = avl_nearest(t, where, AVL_AFTER);
+ ASSERT(ss != NULL);
+ }
+
+ if (ss != NULL) {
+ if (ss->ss_start + size <= ss->ss_end) {
+ *cursor = ss->ss_start + size;
+ return (ss->ss_start);
+ }
+ }
+ return (-1ULL);
+}
+
+static boolean_t
+metaslab_ndf_fragmented(space_map_t *sm)
+{
+ uint64_t max_size = metaslab_pp_maxsize(sm);
+
+ if (max_size > (metaslab_min_alloc_size << metaslab_ndf_clump_shift))
+ return (B_FALSE);
+ return (B_TRUE);
+}
+
+
+static space_map_ops_t metaslab_ndf_ops = {
+ metaslab_pp_load,
+ metaslab_pp_unload,
+ metaslab_ndf_alloc,
+ metaslab_pp_claim,
+ metaslab_pp_free,
+ metaslab_pp_maxsize,
+ metaslab_ndf_fragmented
+};
+
+space_map_ops_t *zfs_metaslab_ops = &metaslab_ndf_ops;
+
+/*
+ * ==========================================================================
+ * 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 (metaslab_debug && smo->smo_object != 0) {
+ mutex_enter(&msp->ms_lock);
+ VERIFY(space_map_load(&msp->ms_map, mg->mg_class->mc_ops,
+ SM_FREE, smo, spa_meta_objset(vd->vdev_spa)) == 0);
+ mutex_exit(&msp->ms_lock);
+ }
+
+ /*
+ * 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) {
+ vdev_dirty(vd, 0, NULL, txg);
+ vdev_dirty(vd, VDD_METASLAB, msp, txg);
+ }
+
+ return (msp);
+}
+
+void
+metaslab_fini(metaslab_t *msp)
+{
+ metaslab_group_t *mg = msp->ms_group;
+
+ vdev_space_update(mg->mg_vd,
+ -msp->ms_smo.smo_alloc, 0, -msp->ms_map.sm_size);
+
+ metaslab_group_remove(mg, msp);
+
+ mutex_enter(&msp->ms_lock);
+
+ space_map_unload(&msp->ms_map);
+ space_map_destroy(&msp->ms_map);
+
+ for (int t = 0; t < TXG_SIZE; t++) {
+ space_map_destroy(&msp->ms_allocmap[t]);
+ space_map_destroy(&msp->ms_freemap[t]);
+ }
+
+ for (int t = 0; t < TXG_DEFER_SIZE; t++)
+ space_map_destroy(&msp->ms_defermap[t]);
+
+ ASSERT3S(msp->ms_deferspace, ==, 0);
+
+ 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)
+
+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 which have
+ * a lower offset than what we've already activated.
+ */
+ if (sm->sm_start <= mg->mg_bonus_area)
+ weight *= (metaslab_smo_bonus_pct / 100);
+ ASSERT(weight >= space &&
+ weight <= 2 * (metaslab_smo_bonus_pct / 100) * space);
+
+ if (sm->sm_loaded && !sm->sm_ops->smop_fragmented(sm)) {
+ /*
+ * 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 void
+metaslab_prefetch(metaslab_group_t *mg)
+{
+ spa_t *spa = mg->mg_vd->vdev_spa;
+ metaslab_t *msp;
+ avl_tree_t *t = &mg->mg_metaslab_tree;
+ int m;
+
+ mutex_enter(&mg->mg_lock);
+
+ /*
+ * Prefetch the next potential metaslabs
+ */
+ for (msp = avl_first(t), m = 0; msp; msp = AVL_NEXT(t, msp), m++) {
+ space_map_t *sm = &msp->ms_map;
+ space_map_obj_t *smo = &msp->ms_smo;
+
+ /* If we have reached our prefetch limit then we're done */
+ if (m >= metaslab_prefetch_limit)
+ break;
+
+ if (!sm->sm_loaded && smo->smo_object != 0) {
+ mutex_exit(&mg->mg_lock);
+ dmu_prefetch(spa_meta_objset(spa), smo->smo_object,
+ 0ULL, smo->smo_objsize);
+ mutex_enter(&mg->mg_lock);
+ }
+ }
+ mutex_exit(&mg->mg_lock);
+}
+
+static int
+metaslab_activate(metaslab_t *msp, uint64_t activation_weight, uint64_t size)
+{
+ metaslab_group_t *mg = msp->ms_group;
+ space_map_t *sm = &msp->ms_map;
+ space_map_ops_t *sm_ops = msp->ms_group->mg_class->mc_ops;
+
+ ASSERT(MUTEX_HELD(&msp->ms_lock));
+
+ if ((msp->ms_weight & METASLAB_ACTIVE_MASK) == 0) {
+ space_map_load_wait(sm);
+ if (!sm->sm_loaded) {
+ int error = space_map_load(sm, sm_ops, SM_FREE,
+ &msp->ms_smo,
+ spa_meta_objset(msp->ms_group->mg_vd->vdev_spa));
+ if (error) {
+ metaslab_group_sort(msp->ms_group, msp, 0);
+ return (error);
+ }
+ for (int t = 0; t < TXG_DEFER_SIZE; t++)
+ space_map_walk(&msp->ms_defermap[t],
+ space_map_claim, sm);
+
+ }
+
+ /*
+ * Track the bonus area as we activate new metaslabs.
+ */
+ if (sm->sm_start > mg->mg_bonus_area) {
+ mutex_enter(&mg->mg_lock);
+ mg->mg_bonus_area = sm->sm_start;
+ mutex_exit(&mg->mg_lock);
+ }
+
+ /*
+ * If we were able to load the map then make sure
+ * that this map is still able to satisfy our request.
+ */
+ if (msp->ms_weight < size)
+ return (ENOSPC);
+
+ 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_meta_objset(spa);
+ 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;
+
+ ASSERT(!vd->vdev_ishole);
+
+ if (allocmap->sm_space == 0 && freemap->sm_space == 0)
+ return;
+
+ /*
+ * 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.
+ */
+
+ tx = dmu_tx_create_assigned(spa_get_dsl(spa), txg);
+
+ if (smo->smo_object == 0) {
+ ASSERT(smo->smo_objsize == 0);
+ ASSERT(smo->smo_alloc == 0);
+ 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 deferred frees (ms_defermap[]),
+ * 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 (int t = 0; t < TXG_DEFER_SIZE; t++)
+ space_map_walk(&msp->ms_defermap[t],
+ space_map_remove, allocmap);
+
+ for (int 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];
+ space_map_t *defer_map = &msp->ms_defermap[txg % TXG_DEFER_SIZE];
+ metaslab_group_t *mg = msp->ms_group;
+ vdev_t *vd = mg->mg_vd;
+ int64_t alloc_delta, defer_delta;
+
+ ASSERT(!vd->vdev_ishole);
+
+ 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 (int 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);
+ }
+
+ for (int t = 0; t < TXG_DEFER_SIZE; t++)
+ space_map_create(&msp->ms_defermap[t], sm->sm_start,
+ sm->sm_size, sm->sm_shift, sm->sm_lock);
+
+ vdev_space_update(vd, 0, 0, sm->sm_size);
+ }
+
+ alloc_delta = smosync->smo_alloc - smo->smo_alloc;
+ defer_delta = freed_map->sm_space - defer_map->sm_space;
+
+ vdev_space_update(vd, alloc_delta + defer_delta, defer_delta, 0);
+
+ 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 defer_map (oldest deferred frees) to this map and
+ * transfer freed_map (this txg's frees) to defer_map.
+ */
+ space_map_load_wait(sm);
+ space_map_vacate(defer_map, sm->sm_loaded ? space_map_free : NULL, sm);
+ space_map_vacate(freed_map, space_map_add, defer_map);
+
+ *smo = *smosync;
+
+ msp->ms_deferspace += defer_delta;
+ ASSERT3S(msp->ms_deferspace, >=, 0);
+ ASSERT3S(msp->ms_deferspace, <=, sm->sm_size);
+ if (msp->ms_deferspace != 0) {
+ /*
+ * Keep syncing this metaslab until all deferred frees
+ * are back in circulation.
+ */
+ vdev_dirty(vd, VDD_METASLAB, msp, txg + 1);
+ }
+
+ /*
+ * 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 (int t = 1; t < TXG_CONCURRENT_STATES; t++)
+ if (msp->ms_allocmap[(txg + t) & TXG_MASK].sm_space)
+ evictable = 0;
+
+ if (evictable && !metaslab_debug)
+ space_map_unload(sm);
+ }
+
+ metaslab_group_sort(mg, msp, metaslab_weight(msp));
+
+ mutex_exit(&msp->ms_lock);
+}
+
+void
+metaslab_sync_reassess(metaslab_group_t *mg)
+{
+ vdev_t *vd = mg->mg_vd;
+
+ /*
+ * Re-evaluate all metaslabs which have lower offsets than the
+ * bonus area.
+ */
+ for (int m = 0; m < vd->vdev_ms_count; m++) {
+ metaslab_t *msp = vd->vdev_ms[m];
+
+ if (msp->ms_map.sm_start > mg->mg_bonus_area)
+ break;
+
+ mutex_enter(&msp->ms_lock);
+ metaslab_group_sort(mg, msp, metaslab_weight(msp));
+ mutex_exit(&msp->ms_lock);
+ }
+
+ /*
+ * Prefetch the next potential metaslabs
+ */
+ metaslab_prefetch(mg);
+}
+
+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;
+ break;
+ }
+ }
+
+ for (;;) {
+ boolean_t was_active;
+
+ 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);
+ }
+
+ was_active = msp->ms_weight & METASLAB_ACTIVE_MASK;
+ 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 || (was_active &&
+ !(msp->ms_weight & METASLAB_ACTIVE_MASK) &&
+ activation_weight == METASLAB_WEIGHT_PRIMARY)) {
+ 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, size) != 0) {
+ mutex_exit(&msp->ms_lock);
+ continue;
+ }
+
+ if ((offset = space_map_alloc(&msp->ms_map, size)) != -1ULL)
+ break;
+
+ metaslab_passivate(msp, space_map_maxsize(&msp->ms_map));
+
+ 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;
+ int zio_lock = B_FALSE;
+ boolean_t allocatable;
+ 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 && (ddi_get_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_aliquot 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]));
+
+ /*
+ * It's possible the vdev we're using as the hint no
+ * longer exists (i.e. removed). Consult the rotor when
+ * all else fails.
+ */
+ if (vd != NULL) {
+ mg = vd->vdev_mg;
+
+ if (flags & METASLAB_HINTBP_AVOID &&
+ mg->mg_next != NULL)
+ mg = mg->mg_next;
+ } else {
+ mg = mc->mc_rotor;
+ }
+ } 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 metaslab class, or into a
+ * metaslab group that has been passivated, just follow the rotor.
+ */
+ if (mg->mg_class != mc || mg->mg_activation_count <= 0)
+ mg = mc->mc_rotor;
+
+ rotor = mg;
+top:
+ all_zero = B_TRUE;
+ do {
+ ASSERT(mg->mg_activation_count == 1);
+
+ vd = mg->mg_vd;
+
+ /*
+ * Don't allocate from faulted devices.
+ */
+ if (zio_lock) {
+ spa_config_enter(spa, SCL_ZIO, FTAG, RW_READER);
+ allocatable = vdev_allocatable(vd);
+ spa_config_exit(spa, SCL_ZIO, FTAG);
+ } else {
+ allocatable = vdev_allocatable(vd);
+ }
+ if (!allocatable)
+ 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_aliquot == 0) {
+ vdev_stat_t *vs = &vd->vdev_stat;
+ int64_t vu, cu;
+
+ /*
+ * Determine percent used in units of 0..1024.
+ * (This is just to avoid floating point.)
+ */
+ vu = (vs->vs_alloc << 10) / (vs->vs_space + 1);
+ cu = (mc->mc_alloc << 10) / (mc->mc_space + 1);
+
+ /*
+ * Bias by at most +/- 25% of the aliquot.
+ */
+ mg->mg_bias = ((cu - vu) *
+ (int64_t)mg->mg_aliquot) / (1024 * 4);
+ }
+
+ if (atomic_add_64_nv(&mc->mc_aliquot, asize) >=
+ mg->mg_aliquot + mg->mg_bias) {
+ mc->mc_rotor = mg->mg_next;
+ mc->mc_aliquot = 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_aliquot = 0;
+ } while ((mg = mg->mg_next) != rotor);
+
+ if (!all_zero) {
+ dshift++;
+ ASSERT(dshift < 64);
+ goto top;
+ }
+
+ if (!allocatable && !zio_lock) {
+ dshift = 3;
+ zio_lock = B_TRUE;
+ 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 = 0;
+
+ 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);
+
+ if ((txg != 0 && spa_writeable(spa)) || !msp->ms_map.sm_loaded)
+ error = metaslab_activate(msp, METASLAB_WEIGHT_SECONDARY, 0);
+
+ if (error == 0 && !space_map_contains(&msp->ms_map, offset, size))
+ error = ENOENT;
+
+ 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_writeable(spa)) { /* 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);
+ ASSERT(BP_PHYSICAL_BIRTH(bp) == 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_SET_BIRTH(bp, txg, 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_syncing_txg(spa));
+
+ 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);
+}