Joe Thornber | 3241b1d | 2011-10-31 20:19:11 +0000 | [diff] [blame] | 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> |
Paul Gortmaker | 1944ce60 | 2011-09-28 18:29:32 -0400 | [diff] [blame] | 15 | #include <linux/export.h> |
Joe Thornber | 3241b1d | 2011-10-31 20:19:11 +0000 | [diff] [blame] | 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 | /*----------------------------------------------------------------*/ |