| /* |
| * 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 2009 Sun Microsystems, Inc. All rights reserved. |
| * Use is subject to license terms. |
| */ |
| /* |
| * Copyright (c) 2013, 2015 by Delphix. All rights reserved. |
| */ |
| |
| #include <sys/zfs_context.h> |
| #include <sys/range_tree.h> |
| #include <sys/space_reftree.h> |
| |
| /* |
| * Space reference trees. |
| * |
| * A range tree is a collection of integers. Every integer is either |
| * in the tree, or it's not. A space reference tree generalizes |
| * the idea: it allows its members to have arbitrary reference counts, |
| * as opposed to the implicit reference count of 0 or 1 in a range tree. |
| * This representation comes in handy when computing the union or |
| * intersection of multiple space maps. For example, the union of |
| * N range trees is the subset of the reference tree with refcnt >= 1. |
| * The intersection of N range trees is the subset with refcnt >= N. |
| * |
| * [It's very much like a Fourier transform. Unions and intersections |
| * are hard to perform in the 'range tree domain', so we convert the trees |
| * into the 'reference count domain', where it's trivial, then invert.] |
| * |
| * vdev_dtl_reassess() uses computations of this form to determine |
| * DTL_MISSING and DTL_OUTAGE for interior vdevs -- e.g. a RAID-Z vdev |
| * has an outage wherever refcnt >= vdev_nparity + 1, and a mirror vdev |
| * has an outage wherever refcnt >= vdev_children. |
| */ |
| static int |
| space_reftree_compare(const void *x1, const void *x2) |
| { |
| const space_ref_t *sr1 = (const space_ref_t *)x1; |
| const space_ref_t *sr2 = (const space_ref_t *)x2; |
| |
| int cmp = AVL_CMP(sr1->sr_offset, sr2->sr_offset); |
| if (likely(cmp)) |
| return (cmp); |
| |
| return (AVL_PCMP(sr1, sr2)); |
| } |
| |
| void |
| space_reftree_create(avl_tree_t *t) |
| { |
| avl_create(t, space_reftree_compare, |
| sizeof (space_ref_t), offsetof(space_ref_t, sr_node)); |
| } |
| |
| void |
| space_reftree_destroy(avl_tree_t *t) |
| { |
| space_ref_t *sr; |
| void *cookie = NULL; |
| |
| while ((sr = avl_destroy_nodes(t, &cookie)) != NULL) |
| kmem_free(sr, sizeof (*sr)); |
| |
| avl_destroy(t); |
| } |
| |
| static void |
| space_reftree_add_node(avl_tree_t *t, uint64_t offset, int64_t refcnt) |
| { |
| space_ref_t *sr; |
| |
| sr = kmem_alloc(sizeof (*sr), KM_SLEEP); |
| sr->sr_offset = offset; |
| sr->sr_refcnt = refcnt; |
| |
| avl_add(t, sr); |
| } |
| |
| void |
| space_reftree_add_seg(avl_tree_t *t, uint64_t start, uint64_t end, |
| int64_t refcnt) |
| { |
| space_reftree_add_node(t, start, refcnt); |
| space_reftree_add_node(t, end, -refcnt); |
| } |
| |
| /* |
| * Convert (or add) a range tree into a reference tree. |
| */ |
| void |
| space_reftree_add_map(avl_tree_t *t, range_tree_t *rt, int64_t refcnt) |
| { |
| range_seg_t *rs; |
| |
| for (rs = avl_first(&rt->rt_root); rs; rs = AVL_NEXT(&rt->rt_root, rs)) |
| space_reftree_add_seg(t, rs->rs_start, rs->rs_end, refcnt); |
| } |
| |
| /* |
| * Convert a reference tree into a range tree. The range tree will contain |
| * all members of the reference tree for which refcnt >= minref. |
| */ |
| void |
| space_reftree_generate_map(avl_tree_t *t, range_tree_t *rt, int64_t minref) |
| { |
| uint64_t start = -1ULL; |
| int64_t refcnt = 0; |
| space_ref_t *sr; |
| |
| range_tree_vacate(rt, NULL, NULL); |
| |
| for (sr = avl_first(t); sr != NULL; sr = AVL_NEXT(t, sr)) { |
| refcnt += sr->sr_refcnt; |
| if (refcnt >= minref) { |
| if (start == -1ULL) { |
| start = sr->sr_offset; |
| } |
| } else { |
| if (start != -1ULL) { |
| uint64_t end = sr->sr_offset; |
| ASSERT(start <= end); |
| if (end > start) |
| range_tree_add(rt, start, end - start); |
| start = -1ULL; |
| } |
| } |
| } |
| ASSERT(refcnt == 0); |
| ASSERT(start == -1ULL); |
| } |