1 /* 2 * Copyright (C) 2011 Red Hat, Inc. 3 * 4 * This file is released under the GPL. 5 */ 6 7 #include "dm-space-map-common.h" 8 #include "dm-space-map-disk.h" 9 #include "dm-space-map.h" 10 #include "dm-transaction-manager.h" 11 12 #include <linux/list.h> 13 #include <linux/slab.h> 14 #include <linux/export.h> 15 #include <linux/device-mapper.h> 16 17 #define DM_MSG_PREFIX "space map disk" 18 19 /*----------------------------------------------------------------*/ 20 21 /* 22 * Space map interface. 23 */ 24 struct sm_disk { 25 struct dm_space_map sm; 26 27 struct ll_disk ll; 28 struct ll_disk old_ll; 29 30 dm_block_t begin; 31 dm_block_t nr_allocated_this_transaction; 32 }; 33 34 static void sm_disk_destroy(struct dm_space_map *sm) 35 { 36 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 37 38 kfree(smd); 39 } 40 41 static int sm_disk_extend(struct dm_space_map *sm, dm_block_t extra_blocks) 42 { 43 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 44 45 return sm_ll_extend(&smd->ll, extra_blocks); 46 } 47 48 static int sm_disk_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count) 49 { 50 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 51 *count = smd->old_ll.nr_blocks; 52 53 return 0; 54 } 55 56 static int sm_disk_get_nr_free(struct dm_space_map *sm, dm_block_t *count) 57 { 58 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 59 *count = (smd->old_ll.nr_blocks - smd->old_ll.nr_allocated) - smd->nr_allocated_this_transaction; 60 61 return 0; 62 } 63 64 static int sm_disk_get_count(struct dm_space_map *sm, dm_block_t b, 65 uint32_t *result) 66 { 67 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 68 return sm_ll_lookup(&smd->ll, b, result); 69 } 70 71 static int sm_disk_count_is_more_than_one(struct dm_space_map *sm, dm_block_t b, 72 int *result) 73 { 74 int r; 75 uint32_t count; 76 77 r = sm_disk_get_count(sm, b, &count); 78 if (r) 79 return r; 80 81 *result = count > 1; 82 83 return 0; 84 } 85 86 static int sm_disk_set_count(struct dm_space_map *sm, dm_block_t b, 87 uint32_t count) 88 { 89 int r; 90 uint32_t old_count; 91 enum allocation_event ev; 92 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 93 94 r = sm_ll_insert(&smd->ll, b, count, &ev); 95 if (!r) { 96 switch (ev) { 97 case SM_NONE: 98 break; 99 100 case SM_ALLOC: 101 /* 102 * This _must_ be free in the prior transaction 103 * otherwise we've lost atomicity. 104 */ 105 smd->nr_allocated_this_transaction++; 106 break; 107 108 case SM_FREE: 109 /* 110 * It's only free if it's also free in the last 111 * transaction. 112 */ 113 r = sm_ll_lookup(&smd->old_ll, b, &old_count); 114 if (r) 115 return r; 116 117 if (!old_count) 118 smd->nr_allocated_this_transaction--; 119 break; 120 } 121 } 122 123 return r; 124 } 125 126 static int sm_disk_inc_block(struct dm_space_map *sm, dm_block_t b) 127 { 128 int r; 129 enum allocation_event ev; 130 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 131 132 r = sm_ll_inc(&smd->ll, b, &ev); 133 if (!r && (ev == SM_ALLOC)) 134 /* 135 * This _must_ be free in the prior transaction 136 * otherwise we've lost atomicity. 137 */ 138 smd->nr_allocated_this_transaction++; 139 140 return r; 141 } 142 143 static int sm_disk_dec_block(struct dm_space_map *sm, dm_block_t b) 144 { 145 int r; 146 uint32_t old_count; 147 enum allocation_event ev; 148 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 149 150 r = sm_ll_dec(&smd->ll, b, &ev); 151 if (!r && (ev == SM_FREE)) { 152 /* 153 * It's only free if it's also free in the last 154 * transaction. 155 */ 156 r = sm_ll_lookup(&smd->old_ll, b, &old_count); 157 if (!r && !old_count) 158 smd->nr_allocated_this_transaction--; 159 } 160 161 return r; 162 } 163 164 static int sm_disk_new_block(struct dm_space_map *sm, dm_block_t *b) 165 { 166 int r; 167 enum allocation_event ev; 168 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 169 170 /* 171 * Any block we allocate has to be free in both the old and current ll. 172 */ 173 r = sm_ll_find_common_free_block(&smd->old_ll, &smd->ll, smd->begin, smd->ll.nr_blocks, b); 174 if (r) 175 return r; 176 177 smd->begin = *b + 1; 178 r = sm_ll_inc(&smd->ll, *b, &ev); 179 if (!r) { 180 BUG_ON(ev != SM_ALLOC); 181 smd->nr_allocated_this_transaction++; 182 } 183 184 return r; 185 } 186 187 static int sm_disk_commit(struct dm_space_map *sm) 188 { 189 int r; 190 dm_block_t nr_free; 191 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 192 193 r = sm_disk_get_nr_free(sm, &nr_free); 194 if (r) 195 return r; 196 197 r = sm_ll_commit(&smd->ll); 198 if (r) 199 return r; 200 201 memcpy(&smd->old_ll, &smd->ll, sizeof(smd->old_ll)); 202 smd->begin = 0; 203 smd->nr_allocated_this_transaction = 0; 204 205 r = sm_disk_get_nr_free(sm, &nr_free); 206 if (r) 207 return r; 208 209 return 0; 210 } 211 212 static int sm_disk_root_size(struct dm_space_map *sm, size_t *result) 213 { 214 *result = sizeof(struct disk_sm_root); 215 216 return 0; 217 } 218 219 static int sm_disk_copy_root(struct dm_space_map *sm, void *where_le, size_t max) 220 { 221 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 222 struct disk_sm_root root_le; 223 224 root_le.nr_blocks = cpu_to_le64(smd->ll.nr_blocks); 225 root_le.nr_allocated = cpu_to_le64(smd->ll.nr_allocated); 226 root_le.bitmap_root = cpu_to_le64(smd->ll.bitmap_root); 227 root_le.ref_count_root = cpu_to_le64(smd->ll.ref_count_root); 228 229 if (max < sizeof(root_le)) 230 return -ENOSPC; 231 232 memcpy(where_le, &root_le, sizeof(root_le)); 233 234 return 0; 235 } 236 237 /*----------------------------------------------------------------*/ 238 239 static struct dm_space_map ops = { 240 .destroy = sm_disk_destroy, 241 .extend = sm_disk_extend, 242 .get_nr_blocks = sm_disk_get_nr_blocks, 243 .get_nr_free = sm_disk_get_nr_free, 244 .get_count = sm_disk_get_count, 245 .count_is_more_than_one = sm_disk_count_is_more_than_one, 246 .set_count = sm_disk_set_count, 247 .inc_block = sm_disk_inc_block, 248 .dec_block = sm_disk_dec_block, 249 .new_block = sm_disk_new_block, 250 .commit = sm_disk_commit, 251 .root_size = sm_disk_root_size, 252 .copy_root = sm_disk_copy_root, 253 .register_threshold_callback = NULL 254 }; 255 256 struct dm_space_map *dm_sm_disk_create(struct dm_transaction_manager *tm, 257 dm_block_t nr_blocks) 258 { 259 int r; 260 struct sm_disk *smd; 261 262 smd = kmalloc(sizeof(*smd), GFP_KERNEL); 263 if (!smd) 264 return ERR_PTR(-ENOMEM); 265 266 smd->begin = 0; 267 smd->nr_allocated_this_transaction = 0; 268 memcpy(&smd->sm, &ops, sizeof(smd->sm)); 269 270 r = sm_ll_new_disk(&smd->ll, tm); 271 if (r) 272 goto bad; 273 274 r = sm_ll_extend(&smd->ll, nr_blocks); 275 if (r) 276 goto bad; 277 278 r = sm_disk_commit(&smd->sm); 279 if (r) 280 goto bad; 281 282 return &smd->sm; 283 284 bad: 285 kfree(smd); 286 return ERR_PTR(r); 287 } 288 EXPORT_SYMBOL_GPL(dm_sm_disk_create); 289 290 struct dm_space_map *dm_sm_disk_open(struct dm_transaction_manager *tm, 291 void *root_le, size_t len) 292 { 293 int r; 294 struct sm_disk *smd; 295 296 smd = kmalloc(sizeof(*smd), GFP_KERNEL); 297 if (!smd) 298 return ERR_PTR(-ENOMEM); 299 300 smd->begin = 0; 301 smd->nr_allocated_this_transaction = 0; 302 memcpy(&smd->sm, &ops, sizeof(smd->sm)); 303 304 r = sm_ll_open_disk(&smd->ll, tm, root_le, len); 305 if (r) 306 goto bad; 307 308 r = sm_disk_commit(&smd->sm); 309 if (r) 310 goto bad; 311 312 return &smd->sm; 313 314 bad: 315 kfree(smd); 316 return ERR_PTR(r); 317 } 318 EXPORT_SYMBOL_GPL(dm_sm_disk_open); 319 320 /*----------------------------------------------------------------*/ 321