1fa9e4066Sahrens /* 2fa9e4066Sahrens * CDDL HEADER START 3fa9e4066Sahrens * 4fa9e4066Sahrens * The contents of this file are subject to the terms of the 591ebeef5Sahrens * Common Development and Distribution License (the "License"). 691ebeef5Sahrens * You may not use this file except in compliance with the License. 7fa9e4066Sahrens * 8fa9e4066Sahrens * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9fa9e4066Sahrens * or http://www.opensolaris.org/os/licensing. 10fa9e4066Sahrens * See the License for the specific language governing permissions 11fa9e4066Sahrens * and limitations under the License. 12fa9e4066Sahrens * 13fa9e4066Sahrens * When distributing Covered Code, include this CDDL HEADER in each 14fa9e4066Sahrens * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15fa9e4066Sahrens * If applicable, add the following below this CDDL HEADER, with the 16fa9e4066Sahrens * fields enclosed by brackets "[]" replaced with your own identifying 17fa9e4066Sahrens * information: Portions Copyright [yyyy] [name of copyright owner] 18fa9e4066Sahrens * 19fa9e4066Sahrens * CDDL HEADER END 20fa9e4066Sahrens */ 21fa9e4066Sahrens /* 223f9d6ad7SLin Ling * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. 230f7643c7SGeorge Wilson * Copyright (c) 2012, 2015 by Delphix. All rights reserved. 24fa9e4066Sahrens */ 25fa9e4066Sahrens 26fa9e4066Sahrens #include <sys/zfs_context.h> 27fa9e4066Sahrens #include <sys/refcount.h> 28fa9e4066Sahrens 29744947dcSTom Erickson #ifdef ZFS_DEBUG 30fa9e4066Sahrens 31fa9e4066Sahrens #ifdef _KERNEL 32fa9e4066Sahrens int reference_tracking_enable = FALSE; /* runs out of memory too easily */ 33fa9e4066Sahrens #else 34fa9e4066Sahrens int reference_tracking_enable = TRUE; 35fa9e4066Sahrens #endif 363b2aab18SMatthew Ahrens int reference_history = 3; /* tunable */ 37fa9e4066Sahrens 38fa9e4066Sahrens static kmem_cache_t *reference_cache; 39fa9e4066Sahrens static kmem_cache_t *reference_history_cache; 40fa9e4066Sahrens 41fa9e4066Sahrens void 42e914ace2STim Schumacher zfs_refcount_init(void) 43fa9e4066Sahrens { 44fa9e4066Sahrens reference_cache = kmem_cache_create("reference_cache", 45fa9e4066Sahrens sizeof (reference_t), 0, NULL, NULL, NULL, NULL, NULL, 0); 46fa9e4066Sahrens 47fa9e4066Sahrens reference_history_cache = kmem_cache_create("reference_history_cache", 48fa9e4066Sahrens sizeof (uint64_t), 0, NULL, NULL, NULL, NULL, NULL, 0); 49fa9e4066Sahrens } 50fa9e4066Sahrens 51fa9e4066Sahrens void 52e914ace2STim Schumacher zfs_refcount_fini(void) 53fa9e4066Sahrens { 54fa9e4066Sahrens kmem_cache_destroy(reference_cache); 55fa9e4066Sahrens kmem_cache_destroy(reference_history_cache); 56fa9e4066Sahrens } 57fa9e4066Sahrens 58fa9e4066Sahrens void 59e914ace2STim Schumacher zfs_refcount_create(zfs_refcount_t *rc) 60fa9e4066Sahrens { 6191ebeef5Sahrens mutex_init(&rc->rc_mtx, NULL, MUTEX_DEFAULT, NULL); 62fa9e4066Sahrens list_create(&rc->rc_list, sizeof (reference_t), 63fa9e4066Sahrens offsetof(reference_t, ref_link)); 64fa9e4066Sahrens list_create(&rc->rc_removed, sizeof (reference_t), 65fa9e4066Sahrens offsetof(reference_t, ref_link)); 6691ebeef5Sahrens rc->rc_count = 0; 6791ebeef5Sahrens rc->rc_removed_count = 0; 683b2aab18SMatthew Ahrens rc->rc_tracked = reference_tracking_enable; 693b2aab18SMatthew Ahrens } 703b2aab18SMatthew Ahrens 710f7643c7SGeorge Wilson void 72e914ace2STim Schumacher zfs_refcount_create_tracked(zfs_refcount_t *rc) 730f7643c7SGeorge Wilson { 74e914ace2STim Schumacher zfs_refcount_create(rc); 750f7643c7SGeorge Wilson rc->rc_tracked = B_TRUE; 760f7643c7SGeorge Wilson } 770f7643c7SGeorge Wilson 783b2aab18SMatthew Ahrens void 79e914ace2STim Schumacher zfs_refcount_create_untracked(zfs_refcount_t *rc) 803b2aab18SMatthew Ahrens { 81e914ace2STim Schumacher zfs_refcount_create(rc); 823b2aab18SMatthew Ahrens rc->rc_tracked = B_FALSE; 83fa9e4066Sahrens } 84fa9e4066Sahrens 85fa9e4066Sahrens void 86e914ace2STim Schumacher zfs_refcount_destroy_many(zfs_refcount_t *rc, uint64_t number) 87fa9e4066Sahrens { 88fa9e4066Sahrens reference_t *ref; 89fa9e4066Sahrens 90fa9e4066Sahrens ASSERT(rc->rc_count == number); 91fa9e4066Sahrens while (ref = list_head(&rc->rc_list)) { 92fa9e4066Sahrens list_remove(&rc->rc_list, ref); 93fa9e4066Sahrens kmem_cache_free(reference_cache, ref); 94fa9e4066Sahrens } 95fa9e4066Sahrens list_destroy(&rc->rc_list); 96fa9e4066Sahrens 97fa9e4066Sahrens while (ref = list_head(&rc->rc_removed)) { 98fa9e4066Sahrens list_remove(&rc->rc_removed, ref); 99fa9e4066Sahrens kmem_cache_free(reference_history_cache, ref->ref_removed); 100fa9e4066Sahrens kmem_cache_free(reference_cache, ref); 101fa9e4066Sahrens } 102fa9e4066Sahrens list_destroy(&rc->rc_removed); 103fa9e4066Sahrens mutex_destroy(&rc->rc_mtx); 104fa9e4066Sahrens } 105fa9e4066Sahrens 106fa9e4066Sahrens void 107e914ace2STim Schumacher zfs_refcount_destroy(zfs_refcount_t *rc) 108fa9e4066Sahrens { 109e914ace2STim Schumacher zfs_refcount_destroy_many(rc, 0); 110fa9e4066Sahrens } 111fa9e4066Sahrens 112fa9e4066Sahrens int 113e914ace2STim Schumacher zfs_refcount_is_zero(zfs_refcount_t *rc) 114fa9e4066Sahrens { 115fa9e4066Sahrens return (rc->rc_count == 0); 116fa9e4066Sahrens } 117fa9e4066Sahrens 118fa9e4066Sahrens int64_t 119e914ace2STim Schumacher zfs_refcount_count(zfs_refcount_t *rc) 120fa9e4066Sahrens { 121fa9e4066Sahrens return (rc->rc_count); 122fa9e4066Sahrens } 123fa9e4066Sahrens 124fa9e4066Sahrens int64_t 125e914ace2STim Schumacher zfs_refcount_add_many(zfs_refcount_t *rc, uint64_t number, void *holder) 126fa9e4066Sahrens { 127d5285caeSGeorge Wilson reference_t *ref = NULL; 128fa9e4066Sahrens int64_t count; 129fa9e4066Sahrens 1303b2aab18SMatthew Ahrens if (rc->rc_tracked) { 131fa9e4066Sahrens ref = kmem_cache_alloc(reference_cache, KM_SLEEP); 132fa9e4066Sahrens ref->ref_holder = holder; 133fa9e4066Sahrens ref->ref_number = number; 134fa9e4066Sahrens } 135fa9e4066Sahrens mutex_enter(&rc->rc_mtx); 136fa9e4066Sahrens ASSERT(rc->rc_count >= 0); 1373b2aab18SMatthew Ahrens if (rc->rc_tracked) 138fa9e4066Sahrens list_insert_head(&rc->rc_list, ref); 139fa9e4066Sahrens rc->rc_count += number; 140fa9e4066Sahrens count = rc->rc_count; 141fa9e4066Sahrens mutex_exit(&rc->rc_mtx); 142fa9e4066Sahrens 143fa9e4066Sahrens return (count); 144fa9e4066Sahrens } 145fa9e4066Sahrens 146fa9e4066Sahrens int64_t 147e914ace2STim Schumacher zfs_refcount_add(zfs_refcount_t *rc, void *holder) 148fa9e4066Sahrens { 149e914ace2STim Schumacher return (zfs_refcount_add_many(rc, 1, holder)); 150fa9e4066Sahrens } 151fa9e4066Sahrens 152fa9e4066Sahrens int64_t 153e914ace2STim Schumacher zfs_refcount_remove_many(zfs_refcount_t *rc, uint64_t number, void *holder) 154fa9e4066Sahrens { 155fa9e4066Sahrens reference_t *ref; 156fa9e4066Sahrens int64_t count; 157fa9e4066Sahrens 158fa9e4066Sahrens mutex_enter(&rc->rc_mtx); 159fa9e4066Sahrens ASSERT(rc->rc_count >= number); 160fa9e4066Sahrens 1613b2aab18SMatthew Ahrens if (!rc->rc_tracked) { 162fa9e4066Sahrens rc->rc_count -= number; 163fa9e4066Sahrens count = rc->rc_count; 164fa9e4066Sahrens mutex_exit(&rc->rc_mtx); 165fa9e4066Sahrens return (count); 166fa9e4066Sahrens } 167fa9e4066Sahrens 168fa9e4066Sahrens for (ref = list_head(&rc->rc_list); ref; 169fa9e4066Sahrens ref = list_next(&rc->rc_list, ref)) { 170fa9e4066Sahrens if (ref->ref_holder == holder && ref->ref_number == number) { 171fa9e4066Sahrens list_remove(&rc->rc_list, ref); 172fa9e4066Sahrens if (reference_history > 0) { 173fa9e4066Sahrens ref->ref_removed = 174fa9e4066Sahrens kmem_cache_alloc(reference_history_cache, 175fa9e4066Sahrens KM_SLEEP); 176fa9e4066Sahrens list_insert_head(&rc->rc_removed, ref); 177fa9e4066Sahrens rc->rc_removed_count++; 1783b2aab18SMatthew Ahrens if (rc->rc_removed_count > reference_history) { 179fa9e4066Sahrens ref = list_tail(&rc->rc_removed); 180fa9e4066Sahrens list_remove(&rc->rc_removed, ref); 181fa9e4066Sahrens kmem_cache_free(reference_history_cache, 182fa9e4066Sahrens ref->ref_removed); 183fa9e4066Sahrens kmem_cache_free(reference_cache, ref); 184fa9e4066Sahrens rc->rc_removed_count--; 185fa9e4066Sahrens } 186fa9e4066Sahrens } else { 187fa9e4066Sahrens kmem_cache_free(reference_cache, ref); 188fa9e4066Sahrens } 189fa9e4066Sahrens rc->rc_count -= number; 190fa9e4066Sahrens count = rc->rc_count; 191fa9e4066Sahrens mutex_exit(&rc->rc_mtx); 192fa9e4066Sahrens return (count); 193fa9e4066Sahrens } 194fa9e4066Sahrens } 195fa9e4066Sahrens panic("No such hold %p on refcount %llx", holder, 196fa9e4066Sahrens (u_longlong_t)(uintptr_t)rc); 197fa9e4066Sahrens return (-1); 198fa9e4066Sahrens } 199fa9e4066Sahrens 200fa9e4066Sahrens int64_t 201e914ace2STim Schumacher zfs_refcount_remove(zfs_refcount_t *rc, void *holder) 202fa9e4066Sahrens { 203e914ace2STim Schumacher return (zfs_refcount_remove_many(rc, 1, holder)); 204fa9e4066Sahrens } 205fa9e4066Sahrens 206744947dcSTom Erickson void 207e914ace2STim Schumacher zfs_refcount_transfer(zfs_refcount_t *dst, zfs_refcount_t *src) 208744947dcSTom Erickson { 209744947dcSTom Erickson int64_t count, removed_count; 210744947dcSTom Erickson list_t list, removed; 211744947dcSTom Erickson 212744947dcSTom Erickson list_create(&list, sizeof (reference_t), 213744947dcSTom Erickson offsetof(reference_t, ref_link)); 214744947dcSTom Erickson list_create(&removed, sizeof (reference_t), 215744947dcSTom Erickson offsetof(reference_t, ref_link)); 216744947dcSTom Erickson 217744947dcSTom Erickson mutex_enter(&src->rc_mtx); 218744947dcSTom Erickson count = src->rc_count; 219744947dcSTom Erickson removed_count = src->rc_removed_count; 220744947dcSTom Erickson src->rc_count = 0; 221744947dcSTom Erickson src->rc_removed_count = 0; 222744947dcSTom Erickson list_move_tail(&list, &src->rc_list); 223744947dcSTom Erickson list_move_tail(&removed, &src->rc_removed); 224744947dcSTom Erickson mutex_exit(&src->rc_mtx); 225744947dcSTom Erickson 226744947dcSTom Erickson mutex_enter(&dst->rc_mtx); 227744947dcSTom Erickson dst->rc_count += count; 228744947dcSTom Erickson dst->rc_removed_count += removed_count; 229744947dcSTom Erickson list_move_tail(&dst->rc_list, &list); 230744947dcSTom Erickson list_move_tail(&dst->rc_removed, &removed); 231744947dcSTom Erickson mutex_exit(&dst->rc_mtx); 232744947dcSTom Erickson 233744947dcSTom Erickson list_destroy(&list); 234744947dcSTom Erickson list_destroy(&removed); 235744947dcSTom Erickson } 236744947dcSTom Erickson 237*eb633035STom Caputi /* ARGSUSED */ 238dcbf3bd6SGeorge Wilson void 239*eb633035STom Caputi zfs_refcount_transfer_ownership_many(zfs_refcount_t *rc, uint64_t number, 240*eb633035STom Caputi void *current_holder, void *new_holder) 241dcbf3bd6SGeorge Wilson { 242dcbf3bd6SGeorge Wilson reference_t *ref; 243dcbf3bd6SGeorge Wilson boolean_t found = B_FALSE; 244dcbf3bd6SGeorge Wilson 245dcbf3bd6SGeorge Wilson mutex_enter(&rc->rc_mtx); 246dcbf3bd6SGeorge Wilson if (!rc->rc_tracked) { 247dcbf3bd6SGeorge Wilson mutex_exit(&rc->rc_mtx); 248dcbf3bd6SGeorge Wilson return; 249dcbf3bd6SGeorge Wilson } 250dcbf3bd6SGeorge Wilson 251dcbf3bd6SGeorge Wilson for (ref = list_head(&rc->rc_list); ref; 252dcbf3bd6SGeorge Wilson ref = list_next(&rc->rc_list, ref)) { 253*eb633035STom Caputi if (ref->ref_holder == current_holder && 254*eb633035STom Caputi ref->ref_number == number) { 255dcbf3bd6SGeorge Wilson ref->ref_holder = new_holder; 256dcbf3bd6SGeorge Wilson found = B_TRUE; 257dcbf3bd6SGeorge Wilson break; 258dcbf3bd6SGeorge Wilson } 259dcbf3bd6SGeorge Wilson } 260dcbf3bd6SGeorge Wilson ASSERT(found); 261dcbf3bd6SGeorge Wilson mutex_exit(&rc->rc_mtx); 262dcbf3bd6SGeorge Wilson } 2630f7643c7SGeorge Wilson 264*eb633035STom Caputi void 265*eb633035STom Caputi zfs_refcount_transfer_ownership(zfs_refcount_t *rc, void *current_holder, 266*eb633035STom Caputi void *new_holder) 267*eb633035STom Caputi { 268*eb633035STom Caputi zfs_refcount_transfer_ownership_many(rc, 1, current_holder, 269*eb633035STom Caputi new_holder); 270*eb633035STom Caputi } 271*eb633035STom Caputi 2720f7643c7SGeorge Wilson /* 2730f7643c7SGeorge Wilson * If tracking is enabled, return true if a reference exists that matches 2740f7643c7SGeorge Wilson * the "holder" tag. If tracking is disabled, then return true if a reference 2750f7643c7SGeorge Wilson * might be held. 2760f7643c7SGeorge Wilson */ 2770f7643c7SGeorge Wilson boolean_t 278e914ace2STim Schumacher zfs_refcount_held(zfs_refcount_t *rc, void *holder) 2790f7643c7SGeorge Wilson { 2800f7643c7SGeorge Wilson reference_t *ref; 2810f7643c7SGeorge Wilson 2820f7643c7SGeorge Wilson mutex_enter(&rc->rc_mtx); 2830f7643c7SGeorge Wilson 2840f7643c7SGeorge Wilson if (!rc->rc_tracked) { 2850f7643c7SGeorge Wilson mutex_exit(&rc->rc_mtx); 2860f7643c7SGeorge Wilson return (rc->rc_count > 0); 2870f7643c7SGeorge Wilson } 2880f7643c7SGeorge Wilson 2890f7643c7SGeorge Wilson for (ref = list_head(&rc->rc_list); ref; 2900f7643c7SGeorge Wilson ref = list_next(&rc->rc_list, ref)) { 2910f7643c7SGeorge Wilson if (ref->ref_holder == holder) { 2920f7643c7SGeorge Wilson mutex_exit(&rc->rc_mtx); 2930f7643c7SGeorge Wilson return (B_TRUE); 2940f7643c7SGeorge Wilson } 2950f7643c7SGeorge Wilson } 2960f7643c7SGeorge Wilson mutex_exit(&rc->rc_mtx); 2970f7643c7SGeorge Wilson return (B_FALSE); 2980f7643c7SGeorge Wilson } 2990f7643c7SGeorge Wilson 3000f7643c7SGeorge Wilson /* 3010f7643c7SGeorge Wilson * If tracking is enabled, return true if a reference does not exist that 3020f7643c7SGeorge Wilson * matches the "holder" tag. If tracking is disabled, always return true 3030f7643c7SGeorge Wilson * since the reference might not be held. 3040f7643c7SGeorge Wilson */ 3050f7643c7SGeorge Wilson boolean_t 306e914ace2STim Schumacher zfs_refcount_not_held(zfs_refcount_t *rc, void *holder) 3070f7643c7SGeorge Wilson { 3080f7643c7SGeorge Wilson reference_t *ref; 3090f7643c7SGeorge Wilson 3100f7643c7SGeorge Wilson mutex_enter(&rc->rc_mtx); 3110f7643c7SGeorge Wilson 3120f7643c7SGeorge Wilson if (!rc->rc_tracked) { 3130f7643c7SGeorge Wilson mutex_exit(&rc->rc_mtx); 3140f7643c7SGeorge Wilson return (B_TRUE); 3150f7643c7SGeorge Wilson } 3160f7643c7SGeorge Wilson 3170f7643c7SGeorge Wilson for (ref = list_head(&rc->rc_list); ref; 3180f7643c7SGeorge Wilson ref = list_next(&rc->rc_list, ref)) { 3190f7643c7SGeorge Wilson if (ref->ref_holder == holder) { 3200f7643c7SGeorge Wilson mutex_exit(&rc->rc_mtx); 3210f7643c7SGeorge Wilson return (B_FALSE); 3220f7643c7SGeorge Wilson } 3230f7643c7SGeorge Wilson } 3240f7643c7SGeorge Wilson mutex_exit(&rc->rc_mtx); 3250f7643c7SGeorge Wilson return (B_TRUE); 3260f7643c7SGeorge Wilson } 327744947dcSTom Erickson #endif /* ZFS_DEBUG */ 328