1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or https://opensource.org/licenses/CDDL-1.0. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright (c) 2020, 2021, 2022 by Pawel Jakub Dawidek 23 */ 24 25 #ifndef _SYS_BRT_IMPL_H 26 #define _SYS_BRT_IMPL_H 27 28 #ifdef __cplusplus 29 extern "C" { 30 #endif 31 32 /* 33 * BRT - Block Reference Table. 34 */ 35 #define BRT_OBJECT_VDEV_PREFIX "com.fudosecurity:brt:vdev:" 36 37 /* 38 * We divide each VDEV into 16MB chunks. Each chunk is represented in memory 39 * by a 16bit counter, thus 1TB VDEV requires 128kB of memory: (1TB / 16MB) * 2B 40 * Each element in this array represents how many BRT entries do we have in this 41 * chunk of storage. We always load this entire array into memory and update as 42 * needed. By having it in memory we can quickly tell (during zio_free()) if 43 * there are any BRT entries that we might need to update. 44 * 45 * This value cannot be larger than 16MB, at least as long as we support 46 * 512 byte block sizes. With 512 byte block size we can have exactly 47 * 32768 blocks in 16MB. In 32MB we could have 65536 blocks, which is one too 48 * many for a 16bit counter. 49 */ 50 #define BRT_RANGESIZE (16 * 1024 * 1024) 51 _Static_assert(BRT_RANGESIZE / SPA_MINBLOCKSIZE <= UINT16_MAX, 52 "BRT_RANGESIZE is too large."); 53 /* 54 * We don't want to update the whole structure every time. Maintain bitmap 55 * of dirty blocks within the regions, so that a single bit represents a 56 * block size of entcounts. For example if we have a 1PB vdev then all 57 * entcounts take 128MB of memory ((64TB / 16MB) * 2B). We can divide this 58 * 128MB array of entcounts into 32kB disk blocks, as we don't want to update 59 * the whole 128MB on disk when we have updated only a single entcount. 60 * We maintain a bitmap where each 32kB disk block within 128MB entcounts array 61 * is represented by a single bit. This gives us 4096 bits. A set bit in the 62 * bitmap means that we had a change in at least one of the 16384 entcounts 63 * that reside on a 32kB disk block (32kB / sizeof (uint16_t)). 64 */ 65 #define BRT_BLOCKSIZE (32 * 1024) 66 #define BRT_RANGESIZE_TO_NBLOCKS(size) \ 67 (((size) - 1) / BRT_BLOCKSIZE / sizeof (uint16_t) + 1) 68 69 #define BRT_LITTLE_ENDIAN 0 70 #define BRT_BIG_ENDIAN 1 71 #ifdef _ZFS_LITTLE_ENDIAN 72 #define BRT_NATIVE_BYTEORDER BRT_LITTLE_ENDIAN 73 #define BRT_NON_NATIVE_BYTEORDER BRT_BIG_ENDIAN 74 #else 75 #define BRT_NATIVE_BYTEORDER BRT_BIG_ENDIAN 76 #define BRT_NON_NATIVE_BYTEORDER BRT_LITTLE_ENDIAN 77 #endif 78 79 typedef struct brt_vdev_phys { 80 uint64_t bvp_mos_entries; 81 uint64_t bvp_size; 82 uint64_t bvp_byteorder; 83 uint64_t bvp_totalcount; 84 uint64_t bvp_rangesize; 85 uint64_t bvp_usedspace; 86 uint64_t bvp_savedspace; 87 } brt_vdev_phys_t; 88 89 struct brt_vdev { 90 /* 91 * Pending changes from open contexts. 92 */ 93 kmutex_t bv_pending_lock; 94 avl_tree_t bv_pending_tree[TXG_SIZE]; 95 /* 96 * Protects bv_mos_*. 97 */ 98 krwlock_t bv_mos_entries_lock ____cacheline_aligned; 99 /* 100 * Protects all the fields starting from bv_initiated. 101 */ 102 krwlock_t bv_lock ____cacheline_aligned; 103 /* 104 * VDEV id. 105 */ 106 uint64_t bv_vdevid ____cacheline_aligned; 107 /* 108 * Object number in the MOS for the entcount array and brt_vdev_phys. 109 */ 110 uint64_t bv_mos_brtvdev; 111 /* 112 * Object number in the MOS and dnode for the entries table. 113 */ 114 uint64_t bv_mos_entries; 115 dnode_t *bv_mos_entries_dnode; 116 /* 117 * Is the structure initiated? 118 * (bv_entcount and bv_bitmap are allocated?) 119 */ 120 boolean_t bv_initiated; 121 /* 122 * Does the bv_entcount[] array needs byte swapping? 123 */ 124 boolean_t bv_need_byteswap; 125 /* 126 * Number of entries in the bv_entcount[] array. 127 */ 128 uint64_t bv_size; 129 /* 130 * This is the array with BRT entry count per BRT_RANGESIZE. 131 */ 132 uint16_t *bv_entcount; 133 /* 134 * bv_entcount[] potentially can be a bit too big to sychronize it all 135 * when we just changed few entcounts. The fields below allow us to 136 * track updates to bv_entcount[] array since the last sync. 137 * A single bit in the bv_bitmap represents as many entcounts as can 138 * fit into a single BRT_BLOCKSIZE. 139 * For example we have 65536 entcounts in the bv_entcount array 140 * (so the whole array is 128kB). We updated bv_entcount[2] and 141 * bv_entcount[5]. In that case only first bit in the bv_bitmap will 142 * be set and we will write only first BRT_BLOCKSIZE out of 128kB. 143 */ 144 ulong_t *bv_bitmap; 145 /* 146 * bv_entcount[] needs updating on disk. 147 */ 148 boolean_t bv_entcount_dirty; 149 /* 150 * brt_vdev_phys needs updating on disk. 151 */ 152 boolean_t bv_meta_dirty; 153 /* 154 * Sum of all bv_entcount[]s. 155 */ 156 uint64_t bv_totalcount; 157 /* 158 * Space on disk occupied by cloned blocks (without compression). 159 */ 160 uint64_t bv_usedspace; 161 /* 162 * How much additional space would be occupied without block cloning. 163 */ 164 uint64_t bv_savedspace; 165 /* 166 * Entries to sync. 167 */ 168 avl_tree_t bv_tree; 169 }; 170 171 /* Size of offset / sizeof (uint64_t). */ 172 #define BRT_KEY_WORDS (1) 173 174 #define BRE_OFFSET(bre) (DVA_GET_OFFSET(&(bre)->bre_bp.blk_dva[0])) 175 176 /* 177 * In-core brt entry. 178 * On-disk we use ZAP with offset as the key and count as the value. 179 */ 180 typedef struct brt_entry { 181 avl_node_t bre_node; 182 blkptr_t bre_bp; 183 uint64_t bre_count; 184 uint64_t bre_pcount; 185 } brt_entry_t; 186 187 #ifdef __cplusplus 188 } 189 #endif 190 191 #endif /* _SYS_BRT_IMPL_H */ 192