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 /* FIXME: we should loop round a couple of times */ 171 r = sm_ll_find_free_block(&smd->old_ll, smd->begin, smd->old_ll.nr_blocks, b); 172 if (r) 173 return r; 174 175 smd->begin = *b + 1; 176 r = sm_ll_inc(&smd->ll, *b, &ev); 177 if (!r) { 178 BUG_ON(ev != SM_ALLOC); 179 smd->nr_allocated_this_transaction++; 180 } 181 182 return r; 183 } 184 185 static int sm_disk_commit(struct dm_space_map *sm) 186 { 187 int r; 188 dm_block_t nr_free; 189 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 190 191 r = sm_disk_get_nr_free(sm, &nr_free); 192 if (r) 193 return r; 194 195 r = sm_ll_commit(&smd->ll); 196 if (r) 197 return r; 198 199 memcpy(&smd->old_ll, &smd->ll, sizeof(smd->old_ll)); 200 smd->begin = 0; 201 smd->nr_allocated_this_transaction = 0; 202 203 r = sm_disk_get_nr_free(sm, &nr_free); 204 if (r) 205 return r; 206 207 return 0; 208 } 209 210 static int sm_disk_root_size(struct dm_space_map *sm, size_t *result) 211 { 212 *result = sizeof(struct disk_sm_root); 213 214 return 0; 215 } 216 217 static int sm_disk_copy_root(struct dm_space_map *sm, void *where_le, size_t max) 218 { 219 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 220 struct disk_sm_root root_le; 221 222 root_le.nr_blocks = cpu_to_le64(smd->ll.nr_blocks); 223 root_le.nr_allocated = cpu_to_le64(smd->ll.nr_allocated); 224 root_le.bitmap_root = cpu_to_le64(smd->ll.bitmap_root); 225 root_le.ref_count_root = cpu_to_le64(smd->ll.ref_count_root); 226 227 if (max < sizeof(root_le)) 228 return -ENOSPC; 229 230 memcpy(where_le, &root_le, sizeof(root_le)); 231 232 return 0; 233 } 234 235 /*----------------------------------------------------------------*/ 236 237 static struct dm_space_map ops = { 238 .destroy = sm_disk_destroy, 239 .extend = sm_disk_extend, 240 .get_nr_blocks = sm_disk_get_nr_blocks, 241 .get_nr_free = sm_disk_get_nr_free, 242 .get_count = sm_disk_get_count, 243 .count_is_more_than_one = sm_disk_count_is_more_than_one, 244 .set_count = sm_disk_set_count, 245 .inc_block = sm_disk_inc_block, 246 .dec_block = sm_disk_dec_block, 247 .new_block = sm_disk_new_block, 248 .commit = sm_disk_commit, 249 .root_size = sm_disk_root_size, 250 .copy_root = sm_disk_copy_root, 251 .register_threshold_callback = NULL 252 }; 253 254 struct dm_space_map *dm_sm_disk_create(struct dm_transaction_manager *tm, 255 dm_block_t nr_blocks) 256 { 257 int r; 258 struct sm_disk *smd; 259 260 smd = kmalloc(sizeof(*smd), GFP_KERNEL); 261 if (!smd) 262 return ERR_PTR(-ENOMEM); 263 264 smd->begin = 0; 265 smd->nr_allocated_this_transaction = 0; 266 memcpy(&smd->sm, &ops, sizeof(smd->sm)); 267 268 r = sm_ll_new_disk(&smd->ll, tm); 269 if (r) 270 goto bad; 271 272 r = sm_ll_extend(&smd->ll, nr_blocks); 273 if (r) 274 goto bad; 275 276 r = sm_disk_commit(&smd->sm); 277 if (r) 278 goto bad; 279 280 return &smd->sm; 281 282 bad: 283 kfree(smd); 284 return ERR_PTR(r); 285 } 286 EXPORT_SYMBOL_GPL(dm_sm_disk_create); 287 288 struct dm_space_map *dm_sm_disk_open(struct dm_transaction_manager *tm, 289 void *root_le, size_t len) 290 { 291 int r; 292 struct sm_disk *smd; 293 294 smd = kmalloc(sizeof(*smd), GFP_KERNEL); 295 if (!smd) 296 return ERR_PTR(-ENOMEM); 297 298 smd->begin = 0; 299 smd->nr_allocated_this_transaction = 0; 300 memcpy(&smd->sm, &ops, sizeof(smd->sm)); 301 302 r = sm_ll_open_disk(&smd->ll, tm, root_le, len); 303 if (r) 304 goto bad; 305 306 r = sm_disk_commit(&smd->sm); 307 if (r) 308 goto bad; 309 310 return &smd->sm; 311 312 bad: 313 kfree(smd); 314 return ERR_PTR(r); 315 } 316 EXPORT_SYMBOL_GPL(dm_sm_disk_open); 317 318 /*----------------------------------------------------------------*/ 319