1 /* 2 * Copyright (C) 2011 Red Hat, Inc. 3 * 4 * This file is released under the GPL. 5 */ 6 7 #include "dm-space-map-checker.h" 8 #include "dm-space-map-common.h" 9 #include "dm-space-map-disk.h" 10 #include "dm-space-map.h" 11 #include "dm-transaction-manager.h" 12 13 #include <linux/list.h> 14 #include <linux/slab.h> 15 #include <linux/export.h> 16 #include <linux/device-mapper.h> 17 18 #define DM_MSG_PREFIX "space map disk" 19 20 /*----------------------------------------------------------------*/ 21 22 /* 23 * Space map interface. 24 */ 25 struct sm_disk { 26 struct dm_space_map sm; 27 28 struct ll_disk ll; 29 struct ll_disk old_ll; 30 31 dm_block_t begin; 32 dm_block_t nr_allocated_this_transaction; 33 }; 34 35 static void sm_disk_destroy(struct dm_space_map *sm) 36 { 37 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 38 39 kfree(smd); 40 } 41 42 static int sm_disk_extend(struct dm_space_map *sm, dm_block_t extra_blocks) 43 { 44 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 45 46 return sm_ll_extend(&smd->ll, extra_blocks); 47 } 48 49 static int sm_disk_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count) 50 { 51 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 52 *count = smd->old_ll.nr_blocks; 53 54 return 0; 55 } 56 57 static int sm_disk_get_nr_free(struct dm_space_map *sm, dm_block_t *count) 58 { 59 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 60 *count = (smd->old_ll.nr_blocks - smd->old_ll.nr_allocated) - smd->nr_allocated_this_transaction; 61 62 return 0; 63 } 64 65 static int sm_disk_get_count(struct dm_space_map *sm, dm_block_t b, 66 uint32_t *result) 67 { 68 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 69 return sm_ll_lookup(&smd->ll, b, result); 70 } 71 72 static int sm_disk_count_is_more_than_one(struct dm_space_map *sm, dm_block_t b, 73 int *result) 74 { 75 int r; 76 uint32_t count; 77 78 r = sm_disk_get_count(sm, b, &count); 79 if (r) 80 return r; 81 82 return count > 1; 83 } 84 85 static int sm_disk_set_count(struct dm_space_map *sm, dm_block_t b, 86 uint32_t count) 87 { 88 int r; 89 uint32_t old_count; 90 enum allocation_event ev; 91 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 92 93 r = sm_ll_insert(&smd->ll, b, count, &ev); 94 if (!r) { 95 switch (ev) { 96 case SM_NONE: 97 break; 98 99 case SM_ALLOC: 100 /* 101 * This _must_ be free in the prior transaction 102 * otherwise we've lost atomicity. 103 */ 104 smd->nr_allocated_this_transaction++; 105 break; 106 107 case SM_FREE: 108 /* 109 * It's only free if it's also free in the last 110 * transaction. 111 */ 112 r = sm_ll_lookup(&smd->old_ll, b, &old_count); 113 if (r) 114 return r; 115 116 if (!old_count) 117 smd->nr_allocated_this_transaction--; 118 break; 119 } 120 } 121 122 return r; 123 } 124 125 static int sm_disk_inc_block(struct dm_space_map *sm, dm_block_t b) 126 { 127 int r; 128 enum allocation_event ev; 129 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 130 131 r = sm_ll_inc(&smd->ll, b, &ev); 132 if (!r && (ev == SM_ALLOC)) 133 /* 134 * This _must_ be free in the prior transaction 135 * otherwise we've lost atomicity. 136 */ 137 smd->nr_allocated_this_transaction++; 138 139 return r; 140 } 141 142 static int sm_disk_dec_block(struct dm_space_map *sm, dm_block_t b) 143 { 144 int r; 145 uint32_t old_count; 146 enum allocation_event ev; 147 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 148 149 r = sm_ll_dec(&smd->ll, b, &ev); 150 if (!r && (ev == SM_FREE)) { 151 /* 152 * It's only free if it's also free in the last 153 * transaction. 154 */ 155 r = sm_ll_lookup(&smd->old_ll, b, &old_count); 156 if (r) 157 return r; 158 159 if (!old_count) 160 smd->nr_allocated_this_transaction--; 161 } 162 163 return r; 164 } 165 166 static int sm_disk_new_block(struct dm_space_map *sm, dm_block_t *b) 167 { 168 int r; 169 enum allocation_event ev; 170 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 171 172 /* FIXME: we should loop round a couple of times */ 173 r = sm_ll_find_free_block(&smd->old_ll, smd->begin, smd->old_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 }; 254 255 static struct dm_space_map *dm_sm_disk_create_real( 256 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 } 288 289 struct dm_space_map *dm_sm_disk_create(struct dm_transaction_manager *tm, 290 dm_block_t nr_blocks) 291 { 292 struct dm_space_map *sm = dm_sm_disk_create_real(tm, nr_blocks); 293 return dm_sm_checker_create_fresh(sm); 294 } 295 EXPORT_SYMBOL_GPL(dm_sm_disk_create); 296 297 static struct dm_space_map *dm_sm_disk_open_real( 298 struct dm_transaction_manager *tm, 299 void *root_le, size_t len) 300 { 301 int r; 302 struct sm_disk *smd; 303 304 smd = kmalloc(sizeof(*smd), GFP_KERNEL); 305 if (!smd) 306 return ERR_PTR(-ENOMEM); 307 308 smd->begin = 0; 309 smd->nr_allocated_this_transaction = 0; 310 memcpy(&smd->sm, &ops, sizeof(smd->sm)); 311 312 r = sm_ll_open_disk(&smd->ll, tm, root_le, len); 313 if (r) 314 goto bad; 315 316 r = sm_disk_commit(&smd->sm); 317 if (r) 318 goto bad; 319 320 return &smd->sm; 321 322 bad: 323 kfree(smd); 324 return ERR_PTR(r); 325 } 326 327 struct dm_space_map *dm_sm_disk_open(struct dm_transaction_manager *tm, 328 void *root_le, size_t len) 329 { 330 return dm_sm_checker_create( 331 dm_sm_disk_open_real(tm, root_le, len)); 332 } 333 EXPORT_SYMBOL_GPL(dm_sm_disk_open); 334 335 /*----------------------------------------------------------------*/ 336