dm-space-map-disk.c revision 62662303e7f590fdfbb0070ab820a0ad4267c119
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 */ 25struct 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 35static 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 42static 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 49static 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 57static 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 65static 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 72static 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 85static 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 125static 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 142static 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 166static 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 187static 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 212static 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 219static 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 239static 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 255static 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 284bad: 285 kfree(smd); 286 return ERR_PTR(r); 287} 288 289struct 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 struct dm_space_map *smc; 294 295 if (IS_ERR_OR_NULL(sm)) 296 return sm; 297 298 smc = dm_sm_checker_create_fresh(sm); 299 if (IS_ERR(smc)) 300 dm_sm_destroy(sm); 301 302 return smc; 303} 304EXPORT_SYMBOL_GPL(dm_sm_disk_create); 305 306static struct dm_space_map *dm_sm_disk_open_real( 307 struct dm_transaction_manager *tm, 308 void *root_le, size_t len) 309{ 310 int r; 311 struct sm_disk *smd; 312 313 smd = kmalloc(sizeof(*smd), GFP_KERNEL); 314 if (!smd) 315 return ERR_PTR(-ENOMEM); 316 317 smd->begin = 0; 318 smd->nr_allocated_this_transaction = 0; 319 memcpy(&smd->sm, &ops, sizeof(smd->sm)); 320 321 r = sm_ll_open_disk(&smd->ll, tm, root_le, len); 322 if (r) 323 goto bad; 324 325 r = sm_disk_commit(&smd->sm); 326 if (r) 327 goto bad; 328 329 return &smd->sm; 330 331bad: 332 kfree(smd); 333 return ERR_PTR(r); 334} 335 336struct dm_space_map *dm_sm_disk_open(struct dm_transaction_manager *tm, 337 void *root_le, size_t len) 338{ 339 return dm_sm_checker_create( 340 dm_sm_disk_open_real(tm, root_le, len)); 341} 342EXPORT_SYMBOL_GPL(dm_sm_disk_open); 343 344/*----------------------------------------------------------------*/ 345