Joe Thornber | 991d9fa | 2011-10-31 20:21:18 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2011 Red Hat UK. |
| 3 | * |
| 4 | * This file is released under the GPL. |
| 5 | */ |
| 6 | |
| 7 | #include "dm-thin-metadata.h" |
| 8 | |
| 9 | #include <linux/device-mapper.h> |
| 10 | #include <linux/dm-io.h> |
| 11 | #include <linux/dm-kcopyd.h> |
| 12 | #include <linux/list.h> |
| 13 | #include <linux/init.h> |
| 14 | #include <linux/module.h> |
| 15 | #include <linux/slab.h> |
| 16 | |
| 17 | #define DM_MSG_PREFIX "thin" |
| 18 | |
| 19 | /* |
| 20 | * Tunable constants |
| 21 | */ |
| 22 | #define ENDIO_HOOK_POOL_SIZE 10240 |
| 23 | #define DEFERRED_SET_SIZE 64 |
| 24 | #define MAPPING_POOL_SIZE 1024 |
| 25 | #define PRISON_CELLS 1024 |
| 26 | |
| 27 | /* |
| 28 | * The block size of the device holding pool data must be |
| 29 | * between 64KB and 1GB. |
| 30 | */ |
| 31 | #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (64 * 1024 >> SECTOR_SHIFT) |
| 32 | #define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT) |
| 33 | |
| 34 | /* |
| 35 | * The metadata device is currently limited in size. The limitation is |
| 36 | * checked lower down in dm-space-map-metadata, but we also check it here |
| 37 | * so we can fail early. |
| 38 | * |
| 39 | * We have one block of index, which can hold 255 index entries. Each |
| 40 | * index entry contains allocation info about 16k metadata blocks. |
| 41 | */ |
| 42 | #define METADATA_DEV_MAX_SECTORS (255 * (1 << 14) * (THIN_METADATA_BLOCK_SIZE / (1 << SECTOR_SHIFT))) |
| 43 | |
| 44 | /* |
| 45 | * Device id is restricted to 24 bits. |
| 46 | */ |
| 47 | #define MAX_DEV_ID ((1 << 24) - 1) |
| 48 | |
| 49 | /* |
| 50 | * How do we handle breaking sharing of data blocks? |
| 51 | * ================================================= |
| 52 | * |
| 53 | * We use a standard copy-on-write btree to store the mappings for the |
| 54 | * devices (note I'm talking about copy-on-write of the metadata here, not |
| 55 | * the data). When you take an internal snapshot you clone the root node |
| 56 | * of the origin btree. After this there is no concept of an origin or a |
| 57 | * snapshot. They are just two device trees that happen to point to the |
| 58 | * same data blocks. |
| 59 | * |
| 60 | * When we get a write in we decide if it's to a shared data block using |
| 61 | * some timestamp magic. If it is, we have to break sharing. |
| 62 | * |
| 63 | * Let's say we write to a shared block in what was the origin. The |
| 64 | * steps are: |
| 65 | * |
| 66 | * i) plug io further to this physical block. (see bio_prison code). |
| 67 | * |
| 68 | * ii) quiesce any read io to that shared data block. Obviously |
| 69 | * including all devices that share this block. (see deferred_set code) |
| 70 | * |
| 71 | * iii) copy the data block to a newly allocate block. This step can be |
| 72 | * missed out if the io covers the block. (schedule_copy). |
| 73 | * |
| 74 | * iv) insert the new mapping into the origin's btree |
| 75 | * (process_prepared_mappings). This act of inserting breaks some |
| 76 | * sharing of btree nodes between the two devices. Breaking sharing only |
| 77 | * effects the btree of that specific device. Btrees for the other |
| 78 | * devices that share the block never change. The btree for the origin |
| 79 | * device as it was after the last commit is untouched, ie. we're using |
| 80 | * persistent data structures in the functional programming sense. |
| 81 | * |
| 82 | * v) unplug io to this physical block, including the io that triggered |
| 83 | * the breaking of sharing. |
| 84 | * |
| 85 | * Steps (ii) and (iii) occur in parallel. |
| 86 | * |
| 87 | * The metadata _doesn't_ need to be committed before the io continues. We |
| 88 | * get away with this because the io is always written to a _new_ block. |
| 89 | * If there's a crash, then: |
| 90 | * |
| 91 | * - The origin mapping will point to the old origin block (the shared |
| 92 | * one). This will contain the data as it was before the io that triggered |
| 93 | * the breaking of sharing came in. |
| 94 | * |
| 95 | * - The snap mapping still points to the old block. As it would after |
| 96 | * the commit. |
| 97 | * |
| 98 | * The downside of this scheme is the timestamp magic isn't perfect, and |
| 99 | * will continue to think that data block in the snapshot device is shared |
| 100 | * even after the write to the origin has broken sharing. I suspect data |
| 101 | * blocks will typically be shared by many different devices, so we're |
| 102 | * breaking sharing n + 1 times, rather than n, where n is the number of |
| 103 | * devices that reference this data block. At the moment I think the |
| 104 | * benefits far, far outweigh the disadvantages. |
| 105 | */ |
| 106 | |
| 107 | /*----------------------------------------------------------------*/ |
| 108 | |
| 109 | /* |
| 110 | * Sometimes we can't deal with a bio straight away. We put them in prison |
| 111 | * where they can't cause any mischief. Bios are put in a cell identified |
| 112 | * by a key, multiple bios can be in the same cell. When the cell is |
| 113 | * subsequently unlocked the bios become available. |
| 114 | */ |
| 115 | struct bio_prison; |
| 116 | |
| 117 | struct cell_key { |
| 118 | int virtual; |
| 119 | dm_thin_id dev; |
| 120 | dm_block_t block; |
| 121 | }; |
| 122 | |
| 123 | struct cell { |
| 124 | struct hlist_node list; |
| 125 | struct bio_prison *prison; |
| 126 | struct cell_key key; |
Joe Thornber | 6f94a4c | 2012-03-28 18:41:23 +0100 | [diff] [blame^] | 127 | struct bio *holder; |
Joe Thornber | 991d9fa | 2011-10-31 20:21:18 +0000 | [diff] [blame] | 128 | struct bio_list bios; |
| 129 | }; |
| 130 | |
| 131 | struct bio_prison { |
| 132 | spinlock_t lock; |
| 133 | mempool_t *cell_pool; |
| 134 | |
| 135 | unsigned nr_buckets; |
| 136 | unsigned hash_mask; |
| 137 | struct hlist_head *cells; |
| 138 | }; |
| 139 | |
| 140 | static uint32_t calc_nr_buckets(unsigned nr_cells) |
| 141 | { |
| 142 | uint32_t n = 128; |
| 143 | |
| 144 | nr_cells /= 4; |
| 145 | nr_cells = min(nr_cells, 8192u); |
| 146 | |
| 147 | while (n < nr_cells) |
| 148 | n <<= 1; |
| 149 | |
| 150 | return n; |
| 151 | } |
| 152 | |
| 153 | /* |
| 154 | * @nr_cells should be the number of cells you want in use _concurrently_. |
| 155 | * Don't confuse it with the number of distinct keys. |
| 156 | */ |
| 157 | static struct bio_prison *prison_create(unsigned nr_cells) |
| 158 | { |
| 159 | unsigned i; |
| 160 | uint32_t nr_buckets = calc_nr_buckets(nr_cells); |
| 161 | size_t len = sizeof(struct bio_prison) + |
| 162 | (sizeof(struct hlist_head) * nr_buckets); |
| 163 | struct bio_prison *prison = kmalloc(len, GFP_KERNEL); |
| 164 | |
| 165 | if (!prison) |
| 166 | return NULL; |
| 167 | |
| 168 | spin_lock_init(&prison->lock); |
| 169 | prison->cell_pool = mempool_create_kmalloc_pool(nr_cells, |
| 170 | sizeof(struct cell)); |
| 171 | if (!prison->cell_pool) { |
| 172 | kfree(prison); |
| 173 | return NULL; |
| 174 | } |
| 175 | |
| 176 | prison->nr_buckets = nr_buckets; |
| 177 | prison->hash_mask = nr_buckets - 1; |
| 178 | prison->cells = (struct hlist_head *) (prison + 1); |
| 179 | for (i = 0; i < nr_buckets; i++) |
| 180 | INIT_HLIST_HEAD(prison->cells + i); |
| 181 | |
| 182 | return prison; |
| 183 | } |
| 184 | |
| 185 | static void prison_destroy(struct bio_prison *prison) |
| 186 | { |
| 187 | mempool_destroy(prison->cell_pool); |
| 188 | kfree(prison); |
| 189 | } |
| 190 | |
| 191 | static uint32_t hash_key(struct bio_prison *prison, struct cell_key *key) |
| 192 | { |
| 193 | const unsigned long BIG_PRIME = 4294967291UL; |
| 194 | uint64_t hash = key->block * BIG_PRIME; |
| 195 | |
| 196 | return (uint32_t) (hash & prison->hash_mask); |
| 197 | } |
| 198 | |
| 199 | static int keys_equal(struct cell_key *lhs, struct cell_key *rhs) |
| 200 | { |
| 201 | return (lhs->virtual == rhs->virtual) && |
| 202 | (lhs->dev == rhs->dev) && |
| 203 | (lhs->block == rhs->block); |
| 204 | } |
| 205 | |
| 206 | static struct cell *__search_bucket(struct hlist_head *bucket, |
| 207 | struct cell_key *key) |
| 208 | { |
| 209 | struct cell *cell; |
| 210 | struct hlist_node *tmp; |
| 211 | |
| 212 | hlist_for_each_entry(cell, tmp, bucket, list) |
| 213 | if (keys_equal(&cell->key, key)) |
| 214 | return cell; |
| 215 | |
| 216 | return NULL; |
| 217 | } |
| 218 | |
| 219 | /* |
| 220 | * This may block if a new cell needs allocating. You must ensure that |
| 221 | * cells will be unlocked even if the calling thread is blocked. |
| 222 | * |
Joe Thornber | 6f94a4c | 2012-03-28 18:41:23 +0100 | [diff] [blame^] | 223 | * Returns 1 if the cell was already held, 0 if @inmate is the new holder. |
Joe Thornber | 991d9fa | 2011-10-31 20:21:18 +0000 | [diff] [blame] | 224 | */ |
| 225 | static int bio_detain(struct bio_prison *prison, struct cell_key *key, |
| 226 | struct bio *inmate, struct cell **ref) |
| 227 | { |
Joe Thornber | 6f94a4c | 2012-03-28 18:41:23 +0100 | [diff] [blame^] | 228 | int r = 1; |
Joe Thornber | 991d9fa | 2011-10-31 20:21:18 +0000 | [diff] [blame] | 229 | unsigned long flags; |
| 230 | uint32_t hash = hash_key(prison, key); |
Joe Thornber | 6f94a4c | 2012-03-28 18:41:23 +0100 | [diff] [blame^] | 231 | struct cell *cell, *cell2; |
Joe Thornber | 991d9fa | 2011-10-31 20:21:18 +0000 | [diff] [blame] | 232 | |
| 233 | BUG_ON(hash > prison->nr_buckets); |
| 234 | |
| 235 | spin_lock_irqsave(&prison->lock, flags); |
Joe Thornber | 6f94a4c | 2012-03-28 18:41:23 +0100 | [diff] [blame^] | 236 | |
Joe Thornber | 991d9fa | 2011-10-31 20:21:18 +0000 | [diff] [blame] | 237 | cell = __search_bucket(prison->cells + hash, key); |
Joe Thornber | 6f94a4c | 2012-03-28 18:41:23 +0100 | [diff] [blame^] | 238 | if (cell) { |
| 239 | bio_list_add(&cell->bios, inmate); |
| 240 | goto out; |
Joe Thornber | 991d9fa | 2011-10-31 20:21:18 +0000 | [diff] [blame] | 241 | } |
| 242 | |
Joe Thornber | 6f94a4c | 2012-03-28 18:41:23 +0100 | [diff] [blame^] | 243 | /* |
| 244 | * Allocate a new cell |
| 245 | */ |
Joe Thornber | 991d9fa | 2011-10-31 20:21:18 +0000 | [diff] [blame] | 246 | spin_unlock_irqrestore(&prison->lock, flags); |
Joe Thornber | 6f94a4c | 2012-03-28 18:41:23 +0100 | [diff] [blame^] | 247 | cell2 = mempool_alloc(prison->cell_pool, GFP_NOIO); |
| 248 | spin_lock_irqsave(&prison->lock, flags); |
Joe Thornber | 991d9fa | 2011-10-31 20:21:18 +0000 | [diff] [blame] | 249 | |
Joe Thornber | 6f94a4c | 2012-03-28 18:41:23 +0100 | [diff] [blame^] | 250 | /* |
| 251 | * We've been unlocked, so we have to double check that |
| 252 | * nobody else has inserted this cell in the meantime. |
| 253 | */ |
| 254 | cell = __search_bucket(prison->cells + hash, key); |
| 255 | if (cell) { |
Joe Thornber | 991d9fa | 2011-10-31 20:21:18 +0000 | [diff] [blame] | 256 | mempool_free(cell2, prison->cell_pool); |
Joe Thornber | 6f94a4c | 2012-03-28 18:41:23 +0100 | [diff] [blame^] | 257 | bio_list_add(&cell->bios, inmate); |
| 258 | goto out; |
| 259 | } |
| 260 | |
| 261 | /* |
| 262 | * Use new cell. |
| 263 | */ |
| 264 | cell = cell2; |
| 265 | |
| 266 | cell->prison = prison; |
| 267 | memcpy(&cell->key, key, sizeof(cell->key)); |
| 268 | cell->holder = inmate; |
| 269 | bio_list_init(&cell->bios); |
| 270 | hlist_add_head(&cell->list, prison->cells + hash); |
| 271 | |
| 272 | r = 0; |
| 273 | |
| 274 | out: |
| 275 | spin_unlock_irqrestore(&prison->lock, flags); |
Joe Thornber | 991d9fa | 2011-10-31 20:21:18 +0000 | [diff] [blame] | 276 | |
| 277 | *ref = cell; |
| 278 | |
| 279 | return r; |
| 280 | } |
| 281 | |
| 282 | /* |
| 283 | * @inmates must have been initialised prior to this call |
| 284 | */ |
| 285 | static void __cell_release(struct cell *cell, struct bio_list *inmates) |
| 286 | { |
| 287 | struct bio_prison *prison = cell->prison; |
| 288 | |
| 289 | hlist_del(&cell->list); |
| 290 | |
Joe Thornber | 6f94a4c | 2012-03-28 18:41:23 +0100 | [diff] [blame^] | 291 | bio_list_add(inmates, cell->holder); |
| 292 | bio_list_merge(inmates, &cell->bios); |
Joe Thornber | 991d9fa | 2011-10-31 20:21:18 +0000 | [diff] [blame] | 293 | |
| 294 | mempool_free(cell, prison->cell_pool); |
| 295 | } |
| 296 | |
| 297 | static void cell_release(struct cell *cell, struct bio_list *bios) |
| 298 | { |
| 299 | unsigned long flags; |
| 300 | struct bio_prison *prison = cell->prison; |
| 301 | |
| 302 | spin_lock_irqsave(&prison->lock, flags); |
| 303 | __cell_release(cell, bios); |
| 304 | spin_unlock_irqrestore(&prison->lock, flags); |
| 305 | } |
| 306 | |
| 307 | /* |
| 308 | * There are a couple of places where we put a bio into a cell briefly |
| 309 | * before taking it out again. In these situations we know that no other |
| 310 | * bio may be in the cell. This function releases the cell, and also does |
| 311 | * a sanity check. |
| 312 | */ |
Joe Thornber | 6f94a4c | 2012-03-28 18:41:23 +0100 | [diff] [blame^] | 313 | static void __cell_release_singleton(struct cell *cell, struct bio *bio) |
| 314 | { |
| 315 | hlist_del(&cell->list); |
| 316 | BUG_ON(cell->holder != bio); |
| 317 | BUG_ON(!bio_list_empty(&cell->bios)); |
| 318 | } |
| 319 | |
Joe Thornber | 991d9fa | 2011-10-31 20:21:18 +0000 | [diff] [blame] | 320 | static void cell_release_singleton(struct cell *cell, struct bio *bio) |
| 321 | { |
Joe Thornber | 991d9fa | 2011-10-31 20:21:18 +0000 | [diff] [blame] | 322 | unsigned long flags; |
Joe Thornber | 6f94a4c | 2012-03-28 18:41:23 +0100 | [diff] [blame^] | 323 | struct bio_prison *prison = cell->prison; |
Joe Thornber | 991d9fa | 2011-10-31 20:21:18 +0000 | [diff] [blame] | 324 | |
| 325 | spin_lock_irqsave(&prison->lock, flags); |
Joe Thornber | 6f94a4c | 2012-03-28 18:41:23 +0100 | [diff] [blame^] | 326 | __cell_release_singleton(cell, bio); |
Joe Thornber | 991d9fa | 2011-10-31 20:21:18 +0000 | [diff] [blame] | 327 | spin_unlock_irqrestore(&prison->lock, flags); |
Joe Thornber | 6f94a4c | 2012-03-28 18:41:23 +0100 | [diff] [blame^] | 328 | } |
Joe Thornber | 991d9fa | 2011-10-31 20:21:18 +0000 | [diff] [blame] | 329 | |
Joe Thornber | 6f94a4c | 2012-03-28 18:41:23 +0100 | [diff] [blame^] | 330 | /* |
| 331 | * Sometimes we don't want the holder, just the additional bios. |
| 332 | */ |
| 333 | static void __cell_release_no_holder(struct cell *cell, struct bio_list *inmates) |
| 334 | { |
| 335 | struct bio_prison *prison = cell->prison; |
| 336 | |
| 337 | hlist_del(&cell->list); |
| 338 | bio_list_merge(inmates, &cell->bios); |
| 339 | |
| 340 | mempool_free(cell, prison->cell_pool); |
| 341 | } |
| 342 | |
| 343 | static void cell_release_no_holder(struct cell *cell, struct bio_list *inmates) |
| 344 | { |
| 345 | unsigned long flags; |
| 346 | struct bio_prison *prison = cell->prison; |
| 347 | |
| 348 | spin_lock_irqsave(&prison->lock, flags); |
| 349 | __cell_release_no_holder(cell, inmates); |
| 350 | spin_unlock_irqrestore(&prison->lock, flags); |
Joe Thornber | 991d9fa | 2011-10-31 20:21:18 +0000 | [diff] [blame] | 351 | } |
| 352 | |
| 353 | static void cell_error(struct cell *cell) |
| 354 | { |
| 355 | struct bio_prison *prison = cell->prison; |
| 356 | struct bio_list bios; |
| 357 | struct bio *bio; |
| 358 | unsigned long flags; |
| 359 | |
| 360 | bio_list_init(&bios); |
| 361 | |
| 362 | spin_lock_irqsave(&prison->lock, flags); |
| 363 | __cell_release(cell, &bios); |
| 364 | spin_unlock_irqrestore(&prison->lock, flags); |
| 365 | |
| 366 | while ((bio = bio_list_pop(&bios))) |
| 367 | bio_io_error(bio); |
| 368 | } |
| 369 | |
| 370 | /*----------------------------------------------------------------*/ |
| 371 | |
| 372 | /* |
| 373 | * We use the deferred set to keep track of pending reads to shared blocks. |
| 374 | * We do this to ensure the new mapping caused by a write isn't performed |
| 375 | * until these prior reads have completed. Otherwise the insertion of the |
| 376 | * new mapping could free the old block that the read bios are mapped to. |
| 377 | */ |
| 378 | |
| 379 | struct deferred_set; |
| 380 | struct deferred_entry { |
| 381 | struct deferred_set *ds; |
| 382 | unsigned count; |
| 383 | struct list_head work_items; |
| 384 | }; |
| 385 | |
| 386 | struct deferred_set { |
| 387 | spinlock_t lock; |
| 388 | unsigned current_entry; |
| 389 | unsigned sweeper; |
| 390 | struct deferred_entry entries[DEFERRED_SET_SIZE]; |
| 391 | }; |
| 392 | |
| 393 | static void ds_init(struct deferred_set *ds) |
| 394 | { |
| 395 | int i; |
| 396 | |
| 397 | spin_lock_init(&ds->lock); |
| 398 | ds->current_entry = 0; |
| 399 | ds->sweeper = 0; |
| 400 | for (i = 0; i < DEFERRED_SET_SIZE; i++) { |
| 401 | ds->entries[i].ds = ds; |
| 402 | ds->entries[i].count = 0; |
| 403 | INIT_LIST_HEAD(&ds->entries[i].work_items); |
| 404 | } |
| 405 | } |
| 406 | |
| 407 | static struct deferred_entry *ds_inc(struct deferred_set *ds) |
| 408 | { |
| 409 | unsigned long flags; |
| 410 | struct deferred_entry *entry; |
| 411 | |
| 412 | spin_lock_irqsave(&ds->lock, flags); |
| 413 | entry = ds->entries + ds->current_entry; |
| 414 | entry->count++; |
| 415 | spin_unlock_irqrestore(&ds->lock, flags); |
| 416 | |
| 417 | return entry; |
| 418 | } |
| 419 | |
| 420 | static unsigned ds_next(unsigned index) |
| 421 | { |
| 422 | return (index + 1) % DEFERRED_SET_SIZE; |
| 423 | } |
| 424 | |
| 425 | static void __sweep(struct deferred_set *ds, struct list_head *head) |
| 426 | { |
| 427 | while ((ds->sweeper != ds->current_entry) && |
| 428 | !ds->entries[ds->sweeper].count) { |
| 429 | list_splice_init(&ds->entries[ds->sweeper].work_items, head); |
| 430 | ds->sweeper = ds_next(ds->sweeper); |
| 431 | } |
| 432 | |
| 433 | if ((ds->sweeper == ds->current_entry) && !ds->entries[ds->sweeper].count) |
| 434 | list_splice_init(&ds->entries[ds->sweeper].work_items, head); |
| 435 | } |
| 436 | |
| 437 | static void ds_dec(struct deferred_entry *entry, struct list_head *head) |
| 438 | { |
| 439 | unsigned long flags; |
| 440 | |
| 441 | spin_lock_irqsave(&entry->ds->lock, flags); |
| 442 | BUG_ON(!entry->count); |
| 443 | --entry->count; |
| 444 | __sweep(entry->ds, head); |
| 445 | spin_unlock_irqrestore(&entry->ds->lock, flags); |
| 446 | } |
| 447 | |
| 448 | /* |
| 449 | * Returns 1 if deferred or 0 if no pending items to delay job. |
| 450 | */ |
| 451 | static int ds_add_work(struct deferred_set *ds, struct list_head *work) |
| 452 | { |
| 453 | int r = 1; |
| 454 | unsigned long flags; |
| 455 | unsigned next_entry; |
| 456 | |
| 457 | spin_lock_irqsave(&ds->lock, flags); |
| 458 | if ((ds->sweeper == ds->current_entry) && |
| 459 | !ds->entries[ds->current_entry].count) |
| 460 | r = 0; |
| 461 | else { |
| 462 | list_add(work, &ds->entries[ds->current_entry].work_items); |
| 463 | next_entry = ds_next(ds->current_entry); |
| 464 | if (!ds->entries[next_entry].count) |
| 465 | ds->current_entry = next_entry; |
| 466 | } |
| 467 | spin_unlock_irqrestore(&ds->lock, flags); |
| 468 | |
| 469 | return r; |
| 470 | } |
| 471 | |
| 472 | /*----------------------------------------------------------------*/ |
| 473 | |
| 474 | /* |
| 475 | * Key building. |
| 476 | */ |
| 477 | static void build_data_key(struct dm_thin_device *td, |
| 478 | dm_block_t b, struct cell_key *key) |
| 479 | { |
| 480 | key->virtual = 0; |
| 481 | key->dev = dm_thin_dev_id(td); |
| 482 | key->block = b; |
| 483 | } |
| 484 | |
| 485 | static void build_virtual_key(struct dm_thin_device *td, dm_block_t b, |
| 486 | struct cell_key *key) |
| 487 | { |
| 488 | key->virtual = 1; |
| 489 | key->dev = dm_thin_dev_id(td); |
| 490 | key->block = b; |
| 491 | } |
| 492 | |
| 493 | /*----------------------------------------------------------------*/ |
| 494 | |
| 495 | /* |
| 496 | * A pool device ties together a metadata device and a data device. It |
| 497 | * also provides the interface for creating and destroying internal |
| 498 | * devices. |
| 499 | */ |
| 500 | struct new_mapping; |
| 501 | struct pool { |
| 502 | struct list_head list; |
| 503 | struct dm_target *ti; /* Only set if a pool target is bound */ |
| 504 | |
| 505 | struct mapped_device *pool_md; |
| 506 | struct block_device *md_dev; |
| 507 | struct dm_pool_metadata *pmd; |
| 508 | |
| 509 | uint32_t sectors_per_block; |
| 510 | unsigned block_shift; |
| 511 | dm_block_t offset_mask; |
| 512 | dm_block_t low_water_blocks; |
| 513 | |
| 514 | unsigned zero_new_blocks:1; |
| 515 | unsigned low_water_triggered:1; /* A dm event has been sent */ |
| 516 | unsigned no_free_space:1; /* A -ENOSPC warning has been issued */ |
| 517 | |
| 518 | struct bio_prison *prison; |
| 519 | struct dm_kcopyd_client *copier; |
| 520 | |
| 521 | struct workqueue_struct *wq; |
| 522 | struct work_struct worker; |
| 523 | |
| 524 | unsigned ref_count; |
| 525 | |
| 526 | spinlock_t lock; |
| 527 | struct bio_list deferred_bios; |
| 528 | struct bio_list deferred_flush_bios; |
| 529 | struct list_head prepared_mappings; |
| 530 | |
| 531 | struct bio_list retry_on_resume_list; |
| 532 | |
| 533 | struct deferred_set ds; /* FIXME: move to thin_c */ |
| 534 | |
| 535 | struct new_mapping *next_mapping; |
| 536 | mempool_t *mapping_pool; |
| 537 | mempool_t *endio_hook_pool; |
| 538 | }; |
| 539 | |
| 540 | /* |
| 541 | * Target context for a pool. |
| 542 | */ |
| 543 | struct pool_c { |
| 544 | struct dm_target *ti; |
| 545 | struct pool *pool; |
| 546 | struct dm_dev *data_dev; |
| 547 | struct dm_dev *metadata_dev; |
| 548 | struct dm_target_callbacks callbacks; |
| 549 | |
| 550 | dm_block_t low_water_blocks; |
| 551 | unsigned zero_new_blocks:1; |
| 552 | }; |
| 553 | |
| 554 | /* |
| 555 | * Target context for a thin. |
| 556 | */ |
| 557 | struct thin_c { |
| 558 | struct dm_dev *pool_dev; |
| 559 | dm_thin_id dev_id; |
| 560 | |
| 561 | struct pool *pool; |
| 562 | struct dm_thin_device *td; |
| 563 | }; |
| 564 | |
| 565 | /*----------------------------------------------------------------*/ |
| 566 | |
| 567 | /* |
| 568 | * A global list of pools that uses a struct mapped_device as a key. |
| 569 | */ |
| 570 | static struct dm_thin_pool_table { |
| 571 | struct mutex mutex; |
| 572 | struct list_head pools; |
| 573 | } dm_thin_pool_table; |
| 574 | |
| 575 | static void pool_table_init(void) |
| 576 | { |
| 577 | mutex_init(&dm_thin_pool_table.mutex); |
| 578 | INIT_LIST_HEAD(&dm_thin_pool_table.pools); |
| 579 | } |
| 580 | |
| 581 | static void __pool_table_insert(struct pool *pool) |
| 582 | { |
| 583 | BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); |
| 584 | list_add(&pool->list, &dm_thin_pool_table.pools); |
| 585 | } |
| 586 | |
| 587 | static void __pool_table_remove(struct pool *pool) |
| 588 | { |
| 589 | BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); |
| 590 | list_del(&pool->list); |
| 591 | } |
| 592 | |
| 593 | static struct pool *__pool_table_lookup(struct mapped_device *md) |
| 594 | { |
| 595 | struct pool *pool = NULL, *tmp; |
| 596 | |
| 597 | BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); |
| 598 | |
| 599 | list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) { |
| 600 | if (tmp->pool_md == md) { |
| 601 | pool = tmp; |
| 602 | break; |
| 603 | } |
| 604 | } |
| 605 | |
| 606 | return pool; |
| 607 | } |
| 608 | |
| 609 | static struct pool *__pool_table_lookup_metadata_dev(struct block_device *md_dev) |
| 610 | { |
| 611 | struct pool *pool = NULL, *tmp; |
| 612 | |
| 613 | BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); |
| 614 | |
| 615 | list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) { |
| 616 | if (tmp->md_dev == md_dev) { |
| 617 | pool = tmp; |
| 618 | break; |
| 619 | } |
| 620 | } |
| 621 | |
| 622 | return pool; |
| 623 | } |
| 624 | |
| 625 | /*----------------------------------------------------------------*/ |
| 626 | |
| 627 | static void __requeue_bio_list(struct thin_c *tc, struct bio_list *master) |
| 628 | { |
| 629 | struct bio *bio; |
| 630 | struct bio_list bios; |
| 631 | |
| 632 | bio_list_init(&bios); |
| 633 | bio_list_merge(&bios, master); |
| 634 | bio_list_init(master); |
| 635 | |
| 636 | while ((bio = bio_list_pop(&bios))) { |
| 637 | if (dm_get_mapinfo(bio)->ptr == tc) |
| 638 | bio_endio(bio, DM_ENDIO_REQUEUE); |
| 639 | else |
| 640 | bio_list_add(master, bio); |
| 641 | } |
| 642 | } |
| 643 | |
| 644 | static void requeue_io(struct thin_c *tc) |
| 645 | { |
| 646 | struct pool *pool = tc->pool; |
| 647 | unsigned long flags; |
| 648 | |
| 649 | spin_lock_irqsave(&pool->lock, flags); |
| 650 | __requeue_bio_list(tc, &pool->deferred_bios); |
| 651 | __requeue_bio_list(tc, &pool->retry_on_resume_list); |
| 652 | spin_unlock_irqrestore(&pool->lock, flags); |
| 653 | } |
| 654 | |
| 655 | /* |
| 656 | * This section of code contains the logic for processing a thin device's IO. |
| 657 | * Much of the code depends on pool object resources (lists, workqueues, etc) |
| 658 | * but most is exclusively called from the thin target rather than the thin-pool |
| 659 | * target. |
| 660 | */ |
| 661 | |
| 662 | static dm_block_t get_bio_block(struct thin_c *tc, struct bio *bio) |
| 663 | { |
| 664 | return bio->bi_sector >> tc->pool->block_shift; |
| 665 | } |
| 666 | |
| 667 | static void remap(struct thin_c *tc, struct bio *bio, dm_block_t block) |
| 668 | { |
| 669 | struct pool *pool = tc->pool; |
| 670 | |
| 671 | bio->bi_bdev = tc->pool_dev->bdev; |
| 672 | bio->bi_sector = (block << pool->block_shift) + |
| 673 | (bio->bi_sector & pool->offset_mask); |
| 674 | } |
| 675 | |
| 676 | static void remap_and_issue(struct thin_c *tc, struct bio *bio, |
| 677 | dm_block_t block) |
| 678 | { |
| 679 | struct pool *pool = tc->pool; |
| 680 | unsigned long flags; |
| 681 | |
| 682 | remap(tc, bio, block); |
| 683 | |
| 684 | /* |
| 685 | * Batch together any FUA/FLUSH bios we find and then issue |
| 686 | * a single commit for them in process_deferred_bios(). |
| 687 | */ |
| 688 | if (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) { |
| 689 | spin_lock_irqsave(&pool->lock, flags); |
| 690 | bio_list_add(&pool->deferred_flush_bios, bio); |
| 691 | spin_unlock_irqrestore(&pool->lock, flags); |
| 692 | } else |
| 693 | generic_make_request(bio); |
| 694 | } |
| 695 | |
| 696 | /* |
| 697 | * wake_worker() is used when new work is queued and when pool_resume is |
| 698 | * ready to continue deferred IO processing. |
| 699 | */ |
| 700 | static void wake_worker(struct pool *pool) |
| 701 | { |
| 702 | queue_work(pool->wq, &pool->worker); |
| 703 | } |
| 704 | |
| 705 | /*----------------------------------------------------------------*/ |
| 706 | |
| 707 | /* |
| 708 | * Bio endio functions. |
| 709 | */ |
| 710 | struct endio_hook { |
| 711 | struct thin_c *tc; |
| 712 | bio_end_io_t *saved_bi_end_io; |
| 713 | struct deferred_entry *entry; |
| 714 | }; |
| 715 | |
| 716 | struct new_mapping { |
| 717 | struct list_head list; |
| 718 | |
| 719 | int prepared; |
| 720 | |
| 721 | struct thin_c *tc; |
| 722 | dm_block_t virt_block; |
| 723 | dm_block_t data_block; |
| 724 | struct cell *cell; |
| 725 | int err; |
| 726 | |
| 727 | /* |
| 728 | * If the bio covers the whole area of a block then we can avoid |
| 729 | * zeroing or copying. Instead this bio is hooked. The bio will |
| 730 | * still be in the cell, so care has to be taken to avoid issuing |
| 731 | * the bio twice. |
| 732 | */ |
| 733 | struct bio *bio; |
| 734 | bio_end_io_t *saved_bi_end_io; |
| 735 | }; |
| 736 | |
| 737 | static void __maybe_add_mapping(struct new_mapping *m) |
| 738 | { |
| 739 | struct pool *pool = m->tc->pool; |
| 740 | |
| 741 | if (list_empty(&m->list) && m->prepared) { |
| 742 | list_add(&m->list, &pool->prepared_mappings); |
| 743 | wake_worker(pool); |
| 744 | } |
| 745 | } |
| 746 | |
| 747 | static void copy_complete(int read_err, unsigned long write_err, void *context) |
| 748 | { |
| 749 | unsigned long flags; |
| 750 | struct new_mapping *m = context; |
| 751 | struct pool *pool = m->tc->pool; |
| 752 | |
| 753 | m->err = read_err || write_err ? -EIO : 0; |
| 754 | |
| 755 | spin_lock_irqsave(&pool->lock, flags); |
| 756 | m->prepared = 1; |
| 757 | __maybe_add_mapping(m); |
| 758 | spin_unlock_irqrestore(&pool->lock, flags); |
| 759 | } |
| 760 | |
| 761 | static void overwrite_endio(struct bio *bio, int err) |
| 762 | { |
| 763 | unsigned long flags; |
| 764 | struct new_mapping *m = dm_get_mapinfo(bio)->ptr; |
| 765 | struct pool *pool = m->tc->pool; |
| 766 | |
| 767 | m->err = err; |
| 768 | |
| 769 | spin_lock_irqsave(&pool->lock, flags); |
| 770 | m->prepared = 1; |
| 771 | __maybe_add_mapping(m); |
| 772 | spin_unlock_irqrestore(&pool->lock, flags); |
| 773 | } |
| 774 | |
| 775 | static void shared_read_endio(struct bio *bio, int err) |
| 776 | { |
| 777 | struct list_head mappings; |
| 778 | struct new_mapping *m, *tmp; |
| 779 | struct endio_hook *h = dm_get_mapinfo(bio)->ptr; |
| 780 | unsigned long flags; |
| 781 | struct pool *pool = h->tc->pool; |
| 782 | |
| 783 | bio->bi_end_io = h->saved_bi_end_io; |
| 784 | bio_endio(bio, err); |
| 785 | |
| 786 | INIT_LIST_HEAD(&mappings); |
| 787 | ds_dec(h->entry, &mappings); |
| 788 | |
| 789 | spin_lock_irqsave(&pool->lock, flags); |
| 790 | list_for_each_entry_safe(m, tmp, &mappings, list) { |
| 791 | list_del(&m->list); |
| 792 | INIT_LIST_HEAD(&m->list); |
| 793 | __maybe_add_mapping(m); |
| 794 | } |
| 795 | spin_unlock_irqrestore(&pool->lock, flags); |
| 796 | |
| 797 | mempool_free(h, pool->endio_hook_pool); |
| 798 | } |
| 799 | |
| 800 | /*----------------------------------------------------------------*/ |
| 801 | |
| 802 | /* |
| 803 | * Workqueue. |
| 804 | */ |
| 805 | |
| 806 | /* |
| 807 | * Prepared mapping jobs. |
| 808 | */ |
| 809 | |
| 810 | /* |
| 811 | * This sends the bios in the cell back to the deferred_bios list. |
| 812 | */ |
| 813 | static void cell_defer(struct thin_c *tc, struct cell *cell, |
| 814 | dm_block_t data_block) |
| 815 | { |
| 816 | struct pool *pool = tc->pool; |
| 817 | unsigned long flags; |
| 818 | |
| 819 | spin_lock_irqsave(&pool->lock, flags); |
| 820 | cell_release(cell, &pool->deferred_bios); |
| 821 | spin_unlock_irqrestore(&tc->pool->lock, flags); |
| 822 | |
| 823 | wake_worker(pool); |
| 824 | } |
| 825 | |
| 826 | /* |
| 827 | * Same as cell_defer above, except it omits one particular detainee, |
| 828 | * a write bio that covers the block and has already been processed. |
| 829 | */ |
Joe Thornber | 6f94a4c | 2012-03-28 18:41:23 +0100 | [diff] [blame^] | 830 | static void cell_defer_except(struct thin_c *tc, struct cell *cell) |
Joe Thornber | 991d9fa | 2011-10-31 20:21:18 +0000 | [diff] [blame] | 831 | { |
| 832 | struct bio_list bios; |
Joe Thornber | 991d9fa | 2011-10-31 20:21:18 +0000 | [diff] [blame] | 833 | struct pool *pool = tc->pool; |
| 834 | unsigned long flags; |
| 835 | |
| 836 | bio_list_init(&bios); |
Joe Thornber | 991d9fa | 2011-10-31 20:21:18 +0000 | [diff] [blame] | 837 | |
| 838 | spin_lock_irqsave(&pool->lock, flags); |
Joe Thornber | 6f94a4c | 2012-03-28 18:41:23 +0100 | [diff] [blame^] | 839 | cell_release_no_holder(cell, &pool->deferred_bios); |
Joe Thornber | 991d9fa | 2011-10-31 20:21:18 +0000 | [diff] [blame] | 840 | spin_unlock_irqrestore(&pool->lock, flags); |
| 841 | |
| 842 | wake_worker(pool); |
| 843 | } |
| 844 | |
| 845 | static void process_prepared_mapping(struct new_mapping *m) |
| 846 | { |
| 847 | struct thin_c *tc = m->tc; |
| 848 | struct bio *bio; |
| 849 | int r; |
| 850 | |
| 851 | bio = m->bio; |
| 852 | if (bio) |
| 853 | bio->bi_end_io = m->saved_bi_end_io; |
| 854 | |
| 855 | if (m->err) { |
| 856 | cell_error(m->cell); |
| 857 | return; |
| 858 | } |
| 859 | |
| 860 | /* |
| 861 | * Commit the prepared block into the mapping btree. |
| 862 | * Any I/O for this block arriving after this point will get |
| 863 | * remapped to it directly. |
| 864 | */ |
| 865 | r = dm_thin_insert_block(tc->td, m->virt_block, m->data_block); |
| 866 | if (r) { |
| 867 | DMERR("dm_thin_insert_block() failed"); |
| 868 | cell_error(m->cell); |
| 869 | return; |
| 870 | } |
| 871 | |
| 872 | /* |
| 873 | * Release any bios held while the block was being provisioned. |
| 874 | * If we are processing a write bio that completely covers the block, |
| 875 | * we already processed it so can ignore it now when processing |
| 876 | * the bios in the cell. |
| 877 | */ |
| 878 | if (bio) { |
Joe Thornber | 6f94a4c | 2012-03-28 18:41:23 +0100 | [diff] [blame^] | 879 | cell_defer_except(tc, m->cell); |
Joe Thornber | 991d9fa | 2011-10-31 20:21:18 +0000 | [diff] [blame] | 880 | bio_endio(bio, 0); |
| 881 | } else |
| 882 | cell_defer(tc, m->cell, m->data_block); |
| 883 | |
| 884 | list_del(&m->list); |
| 885 | mempool_free(m, tc->pool->mapping_pool); |
| 886 | } |
| 887 | |
| 888 | static void process_prepared_mappings(struct pool *pool) |
| 889 | { |
| 890 | unsigned long flags; |
| 891 | struct list_head maps; |
| 892 | struct new_mapping *m, *tmp; |
| 893 | |
| 894 | INIT_LIST_HEAD(&maps); |
| 895 | spin_lock_irqsave(&pool->lock, flags); |
| 896 | list_splice_init(&pool->prepared_mappings, &maps); |
| 897 | spin_unlock_irqrestore(&pool->lock, flags); |
| 898 | |
| 899 | list_for_each_entry_safe(m, tmp, &maps, list) |
| 900 | process_prepared_mapping(m); |
| 901 | } |
| 902 | |
| 903 | /* |
| 904 | * Deferred bio jobs. |
| 905 | */ |
| 906 | static int io_overwrites_block(struct pool *pool, struct bio *bio) |
| 907 | { |
| 908 | return ((bio_data_dir(bio) == WRITE) && |
| 909 | !(bio->bi_sector & pool->offset_mask)) && |
| 910 | (bio->bi_size == (pool->sectors_per_block << SECTOR_SHIFT)); |
| 911 | } |
| 912 | |
| 913 | static void save_and_set_endio(struct bio *bio, bio_end_io_t **save, |
| 914 | bio_end_io_t *fn) |
| 915 | { |
| 916 | *save = bio->bi_end_io; |
| 917 | bio->bi_end_io = fn; |
| 918 | } |
| 919 | |
| 920 | static int ensure_next_mapping(struct pool *pool) |
| 921 | { |
| 922 | if (pool->next_mapping) |
| 923 | return 0; |
| 924 | |
| 925 | pool->next_mapping = mempool_alloc(pool->mapping_pool, GFP_ATOMIC); |
| 926 | |
| 927 | return pool->next_mapping ? 0 : -ENOMEM; |
| 928 | } |
| 929 | |
| 930 | static struct new_mapping *get_next_mapping(struct pool *pool) |
| 931 | { |
| 932 | struct new_mapping *r = pool->next_mapping; |
| 933 | |
| 934 | BUG_ON(!pool->next_mapping); |
| 935 | |
| 936 | pool->next_mapping = NULL; |
| 937 | |
| 938 | return r; |
| 939 | } |
| 940 | |
| 941 | static void schedule_copy(struct thin_c *tc, dm_block_t virt_block, |
| 942 | dm_block_t data_origin, dm_block_t data_dest, |
| 943 | struct cell *cell, struct bio *bio) |
| 944 | { |
| 945 | int r; |
| 946 | struct pool *pool = tc->pool; |
| 947 | struct new_mapping *m = get_next_mapping(pool); |
| 948 | |
| 949 | INIT_LIST_HEAD(&m->list); |
| 950 | m->prepared = 0; |
| 951 | m->tc = tc; |
| 952 | m->virt_block = virt_block; |
| 953 | m->data_block = data_dest; |
| 954 | m->cell = cell; |
| 955 | m->err = 0; |
| 956 | m->bio = NULL; |
| 957 | |
| 958 | ds_add_work(&pool->ds, &m->list); |
| 959 | |
| 960 | /* |
| 961 | * IO to pool_dev remaps to the pool target's data_dev. |
| 962 | * |
| 963 | * If the whole block of data is being overwritten, we can issue the |
| 964 | * bio immediately. Otherwise we use kcopyd to clone the data first. |
| 965 | */ |
| 966 | if (io_overwrites_block(pool, bio)) { |
| 967 | m->bio = bio; |
| 968 | save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio); |
| 969 | dm_get_mapinfo(bio)->ptr = m; |
| 970 | remap_and_issue(tc, bio, data_dest); |
| 971 | } else { |
| 972 | struct dm_io_region from, to; |
| 973 | |
| 974 | from.bdev = tc->pool_dev->bdev; |
| 975 | from.sector = data_origin * pool->sectors_per_block; |
| 976 | from.count = pool->sectors_per_block; |
| 977 | |
| 978 | to.bdev = tc->pool_dev->bdev; |
| 979 | to.sector = data_dest * pool->sectors_per_block; |
| 980 | to.count = pool->sectors_per_block; |
| 981 | |
| 982 | r = dm_kcopyd_copy(pool->copier, &from, 1, &to, |
| 983 | 0, copy_complete, m); |
| 984 | if (r < 0) { |
| 985 | mempool_free(m, pool->mapping_pool); |
| 986 | DMERR("dm_kcopyd_copy() failed"); |
| 987 | cell_error(cell); |
| 988 | } |
| 989 | } |
| 990 | } |
| 991 | |
| 992 | static void schedule_zero(struct thin_c *tc, dm_block_t virt_block, |
| 993 | dm_block_t data_block, struct cell *cell, |
| 994 | struct bio *bio) |
| 995 | { |
| 996 | struct pool *pool = tc->pool; |
| 997 | struct new_mapping *m = get_next_mapping(pool); |
| 998 | |
| 999 | INIT_LIST_HEAD(&m->list); |
| 1000 | m->prepared = 0; |
| 1001 | m->tc = tc; |
| 1002 | m->virt_block = virt_block; |
| 1003 | m->data_block = data_block; |
| 1004 | m->cell = cell; |
| 1005 | m->err = 0; |
| 1006 | m->bio = NULL; |
| 1007 | |
| 1008 | /* |
| 1009 | * If the whole block of data is being overwritten or we are not |
| 1010 | * zeroing pre-existing data, we can issue the bio immediately. |
| 1011 | * Otherwise we use kcopyd to zero the data first. |
| 1012 | */ |
| 1013 | if (!pool->zero_new_blocks) |
| 1014 | process_prepared_mapping(m); |
| 1015 | |
| 1016 | else if (io_overwrites_block(pool, bio)) { |
| 1017 | m->bio = bio; |
| 1018 | save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio); |
| 1019 | dm_get_mapinfo(bio)->ptr = m; |
| 1020 | remap_and_issue(tc, bio, data_block); |
| 1021 | |
| 1022 | } else { |
| 1023 | int r; |
| 1024 | struct dm_io_region to; |
| 1025 | |
| 1026 | to.bdev = tc->pool_dev->bdev; |
| 1027 | to.sector = data_block * pool->sectors_per_block; |
| 1028 | to.count = pool->sectors_per_block; |
| 1029 | |
| 1030 | r = dm_kcopyd_zero(pool->copier, 1, &to, 0, copy_complete, m); |
| 1031 | if (r < 0) { |
| 1032 | mempool_free(m, pool->mapping_pool); |
| 1033 | DMERR("dm_kcopyd_zero() failed"); |
| 1034 | cell_error(cell); |
| 1035 | } |
| 1036 | } |
| 1037 | } |
| 1038 | |
| 1039 | static int alloc_data_block(struct thin_c *tc, dm_block_t *result) |
| 1040 | { |
| 1041 | int r; |
| 1042 | dm_block_t free_blocks; |
| 1043 | unsigned long flags; |
| 1044 | struct pool *pool = tc->pool; |
| 1045 | |
| 1046 | r = dm_pool_get_free_block_count(pool->pmd, &free_blocks); |
| 1047 | if (r) |
| 1048 | return r; |
| 1049 | |
| 1050 | if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) { |
| 1051 | DMWARN("%s: reached low water mark, sending event.", |
| 1052 | dm_device_name(pool->pool_md)); |
| 1053 | spin_lock_irqsave(&pool->lock, flags); |
| 1054 | pool->low_water_triggered = 1; |
| 1055 | spin_unlock_irqrestore(&pool->lock, flags); |
| 1056 | dm_table_event(pool->ti->table); |
| 1057 | } |
| 1058 | |
| 1059 | if (!free_blocks) { |
| 1060 | if (pool->no_free_space) |
| 1061 | return -ENOSPC; |
| 1062 | else { |
| 1063 | /* |
| 1064 | * Try to commit to see if that will free up some |
| 1065 | * more space. |
| 1066 | */ |
| 1067 | r = dm_pool_commit_metadata(pool->pmd); |
| 1068 | if (r) { |
| 1069 | DMERR("%s: dm_pool_commit_metadata() failed, error = %d", |
| 1070 | __func__, r); |
| 1071 | return r; |
| 1072 | } |
| 1073 | |
| 1074 | r = dm_pool_get_free_block_count(pool->pmd, &free_blocks); |
| 1075 | if (r) |
| 1076 | return r; |
| 1077 | |
| 1078 | /* |
| 1079 | * If we still have no space we set a flag to avoid |
| 1080 | * doing all this checking and return -ENOSPC. |
| 1081 | */ |
| 1082 | if (!free_blocks) { |
| 1083 | DMWARN("%s: no free space available.", |
| 1084 | dm_device_name(pool->pool_md)); |
| 1085 | spin_lock_irqsave(&pool->lock, flags); |
| 1086 | pool->no_free_space = 1; |
| 1087 | spin_unlock_irqrestore(&pool->lock, flags); |
| 1088 | return -ENOSPC; |
| 1089 | } |
| 1090 | } |
| 1091 | } |
| 1092 | |
| 1093 | r = dm_pool_alloc_data_block(pool->pmd, result); |
| 1094 | if (r) |
| 1095 | return r; |
| 1096 | |
| 1097 | return 0; |
| 1098 | } |
| 1099 | |
| 1100 | /* |
| 1101 | * If we have run out of space, queue bios until the device is |
| 1102 | * resumed, presumably after having been reloaded with more space. |
| 1103 | */ |
| 1104 | static void retry_on_resume(struct bio *bio) |
| 1105 | { |
| 1106 | struct thin_c *tc = dm_get_mapinfo(bio)->ptr; |
| 1107 | struct pool *pool = tc->pool; |
| 1108 | unsigned long flags; |
| 1109 | |
| 1110 | spin_lock_irqsave(&pool->lock, flags); |
| 1111 | bio_list_add(&pool->retry_on_resume_list, bio); |
| 1112 | spin_unlock_irqrestore(&pool->lock, flags); |
| 1113 | } |
| 1114 | |
| 1115 | static void no_space(struct cell *cell) |
| 1116 | { |
| 1117 | struct bio *bio; |
| 1118 | struct bio_list bios; |
| 1119 | |
| 1120 | bio_list_init(&bios); |
| 1121 | cell_release(cell, &bios); |
| 1122 | |
| 1123 | while ((bio = bio_list_pop(&bios))) |
| 1124 | retry_on_resume(bio); |
| 1125 | } |
| 1126 | |
| 1127 | static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block, |
| 1128 | struct cell_key *key, |
| 1129 | struct dm_thin_lookup_result *lookup_result, |
| 1130 | struct cell *cell) |
| 1131 | { |
| 1132 | int r; |
| 1133 | dm_block_t data_block; |
| 1134 | |
| 1135 | r = alloc_data_block(tc, &data_block); |
| 1136 | switch (r) { |
| 1137 | case 0: |
| 1138 | schedule_copy(tc, block, lookup_result->block, |
| 1139 | data_block, cell, bio); |
| 1140 | break; |
| 1141 | |
| 1142 | case -ENOSPC: |
| 1143 | no_space(cell); |
| 1144 | break; |
| 1145 | |
| 1146 | default: |
| 1147 | DMERR("%s: alloc_data_block() failed, error = %d", __func__, r); |
| 1148 | cell_error(cell); |
| 1149 | break; |
| 1150 | } |
| 1151 | } |
| 1152 | |
| 1153 | static void process_shared_bio(struct thin_c *tc, struct bio *bio, |
| 1154 | dm_block_t block, |
| 1155 | struct dm_thin_lookup_result *lookup_result) |
| 1156 | { |
| 1157 | struct cell *cell; |
| 1158 | struct pool *pool = tc->pool; |
| 1159 | struct cell_key key; |
| 1160 | |
| 1161 | /* |
| 1162 | * If cell is already occupied, then sharing is already in the process |
| 1163 | * of being broken so we have nothing further to do here. |
| 1164 | */ |
| 1165 | build_data_key(tc->td, lookup_result->block, &key); |
| 1166 | if (bio_detain(pool->prison, &key, bio, &cell)) |
| 1167 | return; |
| 1168 | |
| 1169 | if (bio_data_dir(bio) == WRITE) |
| 1170 | break_sharing(tc, bio, block, &key, lookup_result, cell); |
| 1171 | else { |
| 1172 | struct endio_hook *h; |
| 1173 | h = mempool_alloc(pool->endio_hook_pool, GFP_NOIO); |
| 1174 | |
| 1175 | h->tc = tc; |
| 1176 | h->entry = ds_inc(&pool->ds); |
| 1177 | save_and_set_endio(bio, &h->saved_bi_end_io, shared_read_endio); |
| 1178 | dm_get_mapinfo(bio)->ptr = h; |
| 1179 | |
| 1180 | cell_release_singleton(cell, bio); |
| 1181 | remap_and_issue(tc, bio, lookup_result->block); |
| 1182 | } |
| 1183 | } |
| 1184 | |
| 1185 | static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block, |
| 1186 | struct cell *cell) |
| 1187 | { |
| 1188 | int r; |
| 1189 | dm_block_t data_block; |
| 1190 | |
| 1191 | /* |
| 1192 | * Remap empty bios (flushes) immediately, without provisioning. |
| 1193 | */ |
| 1194 | if (!bio->bi_size) { |
| 1195 | cell_release_singleton(cell, bio); |
| 1196 | remap_and_issue(tc, bio, 0); |
| 1197 | return; |
| 1198 | } |
| 1199 | |
| 1200 | /* |
| 1201 | * Fill read bios with zeroes and complete them immediately. |
| 1202 | */ |
| 1203 | if (bio_data_dir(bio) == READ) { |
| 1204 | zero_fill_bio(bio); |
| 1205 | cell_release_singleton(cell, bio); |
| 1206 | bio_endio(bio, 0); |
| 1207 | return; |
| 1208 | } |
| 1209 | |
| 1210 | r = alloc_data_block(tc, &data_block); |
| 1211 | switch (r) { |
| 1212 | case 0: |
| 1213 | schedule_zero(tc, block, data_block, cell, bio); |
| 1214 | break; |
| 1215 | |
| 1216 | case -ENOSPC: |
| 1217 | no_space(cell); |
| 1218 | break; |
| 1219 | |
| 1220 | default: |
| 1221 | DMERR("%s: alloc_data_block() failed, error = %d", __func__, r); |
| 1222 | cell_error(cell); |
| 1223 | break; |
| 1224 | } |
| 1225 | } |
| 1226 | |
| 1227 | static void process_bio(struct thin_c *tc, struct bio *bio) |
| 1228 | { |
| 1229 | int r; |
| 1230 | dm_block_t block = get_bio_block(tc, bio); |
| 1231 | struct cell *cell; |
| 1232 | struct cell_key key; |
| 1233 | struct dm_thin_lookup_result lookup_result; |
| 1234 | |
| 1235 | /* |
| 1236 | * If cell is already occupied, then the block is already |
| 1237 | * being provisioned so we have nothing further to do here. |
| 1238 | */ |
| 1239 | build_virtual_key(tc->td, block, &key); |
| 1240 | if (bio_detain(tc->pool->prison, &key, bio, &cell)) |
| 1241 | return; |
| 1242 | |
| 1243 | r = dm_thin_find_block(tc->td, block, 1, &lookup_result); |
| 1244 | switch (r) { |
| 1245 | case 0: |
| 1246 | /* |
| 1247 | * We can release this cell now. This thread is the only |
| 1248 | * one that puts bios into a cell, and we know there were |
| 1249 | * no preceding bios. |
| 1250 | */ |
| 1251 | /* |
| 1252 | * TODO: this will probably have to change when discard goes |
| 1253 | * back in. |
| 1254 | */ |
| 1255 | cell_release_singleton(cell, bio); |
| 1256 | |
| 1257 | if (lookup_result.shared) |
| 1258 | process_shared_bio(tc, bio, block, &lookup_result); |
| 1259 | else |
| 1260 | remap_and_issue(tc, bio, lookup_result.block); |
| 1261 | break; |
| 1262 | |
| 1263 | case -ENODATA: |
| 1264 | provision_block(tc, bio, block, cell); |
| 1265 | break; |
| 1266 | |
| 1267 | default: |
| 1268 | DMERR("dm_thin_find_block() failed, error = %d", r); |
| 1269 | bio_io_error(bio); |
| 1270 | break; |
| 1271 | } |
| 1272 | } |
| 1273 | |
| 1274 | static void process_deferred_bios(struct pool *pool) |
| 1275 | { |
| 1276 | unsigned long flags; |
| 1277 | struct bio *bio; |
| 1278 | struct bio_list bios; |
| 1279 | int r; |
| 1280 | |
| 1281 | bio_list_init(&bios); |
| 1282 | |
| 1283 | spin_lock_irqsave(&pool->lock, flags); |
| 1284 | bio_list_merge(&bios, &pool->deferred_bios); |
| 1285 | bio_list_init(&pool->deferred_bios); |
| 1286 | spin_unlock_irqrestore(&pool->lock, flags); |
| 1287 | |
| 1288 | while ((bio = bio_list_pop(&bios))) { |
| 1289 | struct thin_c *tc = dm_get_mapinfo(bio)->ptr; |
| 1290 | /* |
| 1291 | * If we've got no free new_mapping structs, and processing |
| 1292 | * this bio might require one, we pause until there are some |
| 1293 | * prepared mappings to process. |
| 1294 | */ |
| 1295 | if (ensure_next_mapping(pool)) { |
| 1296 | spin_lock_irqsave(&pool->lock, flags); |
| 1297 | bio_list_merge(&pool->deferred_bios, &bios); |
| 1298 | spin_unlock_irqrestore(&pool->lock, flags); |
| 1299 | |
| 1300 | break; |
| 1301 | } |
| 1302 | process_bio(tc, bio); |
| 1303 | } |
| 1304 | |
| 1305 | /* |
| 1306 | * If there are any deferred flush bios, we must commit |
| 1307 | * the metadata before issuing them. |
| 1308 | */ |
| 1309 | bio_list_init(&bios); |
| 1310 | spin_lock_irqsave(&pool->lock, flags); |
| 1311 | bio_list_merge(&bios, &pool->deferred_flush_bios); |
| 1312 | bio_list_init(&pool->deferred_flush_bios); |
| 1313 | spin_unlock_irqrestore(&pool->lock, flags); |
| 1314 | |
| 1315 | if (bio_list_empty(&bios)) |
| 1316 | return; |
| 1317 | |
| 1318 | r = dm_pool_commit_metadata(pool->pmd); |
| 1319 | if (r) { |
| 1320 | DMERR("%s: dm_pool_commit_metadata() failed, error = %d", |
| 1321 | __func__, r); |
| 1322 | while ((bio = bio_list_pop(&bios))) |
| 1323 | bio_io_error(bio); |
| 1324 | return; |
| 1325 | } |
| 1326 | |
| 1327 | while ((bio = bio_list_pop(&bios))) |
| 1328 | generic_make_request(bio); |
| 1329 | } |
| 1330 | |
| 1331 | static void do_worker(struct work_struct *ws) |
| 1332 | { |
| 1333 | struct pool *pool = container_of(ws, struct pool, worker); |
| 1334 | |
| 1335 | process_prepared_mappings(pool); |
| 1336 | process_deferred_bios(pool); |
| 1337 | } |
| 1338 | |
| 1339 | /*----------------------------------------------------------------*/ |
| 1340 | |
| 1341 | /* |
| 1342 | * Mapping functions. |
| 1343 | */ |
| 1344 | |
| 1345 | /* |
| 1346 | * Called only while mapping a thin bio to hand it over to the workqueue. |
| 1347 | */ |
| 1348 | static void thin_defer_bio(struct thin_c *tc, struct bio *bio) |
| 1349 | { |
| 1350 | unsigned long flags; |
| 1351 | struct pool *pool = tc->pool; |
| 1352 | |
| 1353 | spin_lock_irqsave(&pool->lock, flags); |
| 1354 | bio_list_add(&pool->deferred_bios, bio); |
| 1355 | spin_unlock_irqrestore(&pool->lock, flags); |
| 1356 | |
| 1357 | wake_worker(pool); |
| 1358 | } |
| 1359 | |
| 1360 | /* |
| 1361 | * Non-blocking function called from the thin target's map function. |
| 1362 | */ |
| 1363 | static int thin_bio_map(struct dm_target *ti, struct bio *bio, |
| 1364 | union map_info *map_context) |
| 1365 | { |
| 1366 | int r; |
| 1367 | struct thin_c *tc = ti->private; |
| 1368 | dm_block_t block = get_bio_block(tc, bio); |
| 1369 | struct dm_thin_device *td = tc->td; |
| 1370 | struct dm_thin_lookup_result result; |
| 1371 | |
| 1372 | /* |
| 1373 | * Save the thin context for easy access from the deferred bio later. |
| 1374 | */ |
| 1375 | map_context->ptr = tc; |
| 1376 | |
| 1377 | if (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) { |
| 1378 | thin_defer_bio(tc, bio); |
| 1379 | return DM_MAPIO_SUBMITTED; |
| 1380 | } |
| 1381 | |
| 1382 | r = dm_thin_find_block(td, block, 0, &result); |
| 1383 | |
| 1384 | /* |
| 1385 | * Note that we defer readahead too. |
| 1386 | */ |
| 1387 | switch (r) { |
| 1388 | case 0: |
| 1389 | if (unlikely(result.shared)) { |
| 1390 | /* |
| 1391 | * We have a race condition here between the |
| 1392 | * result.shared value returned by the lookup and |
| 1393 | * snapshot creation, which may cause new |
| 1394 | * sharing. |
| 1395 | * |
| 1396 | * To avoid this always quiesce the origin before |
| 1397 | * taking the snap. You want to do this anyway to |
| 1398 | * ensure a consistent application view |
| 1399 | * (i.e. lockfs). |
| 1400 | * |
| 1401 | * More distant ancestors are irrelevant. The |
| 1402 | * shared flag will be set in their case. |
| 1403 | */ |
| 1404 | thin_defer_bio(tc, bio); |
| 1405 | r = DM_MAPIO_SUBMITTED; |
| 1406 | } else { |
| 1407 | remap(tc, bio, result.block); |
| 1408 | r = DM_MAPIO_REMAPPED; |
| 1409 | } |
| 1410 | break; |
| 1411 | |
| 1412 | case -ENODATA: |
| 1413 | /* |
| 1414 | * In future, the failed dm_thin_find_block above could |
| 1415 | * provide the hint to load the metadata into cache. |
| 1416 | */ |
| 1417 | case -EWOULDBLOCK: |
| 1418 | thin_defer_bio(tc, bio); |
| 1419 | r = DM_MAPIO_SUBMITTED; |
| 1420 | break; |
| 1421 | } |
| 1422 | |
| 1423 | return r; |
| 1424 | } |
| 1425 | |
| 1426 | static int pool_is_congested(struct dm_target_callbacks *cb, int bdi_bits) |
| 1427 | { |
| 1428 | int r; |
| 1429 | unsigned long flags; |
| 1430 | struct pool_c *pt = container_of(cb, struct pool_c, callbacks); |
| 1431 | |
| 1432 | spin_lock_irqsave(&pt->pool->lock, flags); |
| 1433 | r = !bio_list_empty(&pt->pool->retry_on_resume_list); |
| 1434 | spin_unlock_irqrestore(&pt->pool->lock, flags); |
| 1435 | |
| 1436 | if (!r) { |
| 1437 | struct request_queue *q = bdev_get_queue(pt->data_dev->bdev); |
| 1438 | r = bdi_congested(&q->backing_dev_info, bdi_bits); |
| 1439 | } |
| 1440 | |
| 1441 | return r; |
| 1442 | } |
| 1443 | |
| 1444 | static void __requeue_bios(struct pool *pool) |
| 1445 | { |
| 1446 | bio_list_merge(&pool->deferred_bios, &pool->retry_on_resume_list); |
| 1447 | bio_list_init(&pool->retry_on_resume_list); |
| 1448 | } |
| 1449 | |
| 1450 | /*---------------------------------------------------------------- |
| 1451 | * Binding of control targets to a pool object |
| 1452 | *--------------------------------------------------------------*/ |
| 1453 | static int bind_control_target(struct pool *pool, struct dm_target *ti) |
| 1454 | { |
| 1455 | struct pool_c *pt = ti->private; |
| 1456 | |
| 1457 | pool->ti = ti; |
| 1458 | pool->low_water_blocks = pt->low_water_blocks; |
| 1459 | pool->zero_new_blocks = pt->zero_new_blocks; |
| 1460 | |
| 1461 | return 0; |
| 1462 | } |
| 1463 | |
| 1464 | static void unbind_control_target(struct pool *pool, struct dm_target *ti) |
| 1465 | { |
| 1466 | if (pool->ti == ti) |
| 1467 | pool->ti = NULL; |
| 1468 | } |
| 1469 | |
| 1470 | /*---------------------------------------------------------------- |
| 1471 | * Pool creation |
| 1472 | *--------------------------------------------------------------*/ |
| 1473 | static void __pool_destroy(struct pool *pool) |
| 1474 | { |
| 1475 | __pool_table_remove(pool); |
| 1476 | |
| 1477 | if (dm_pool_metadata_close(pool->pmd) < 0) |
| 1478 | DMWARN("%s: dm_pool_metadata_close() failed.", __func__); |
| 1479 | |
| 1480 | prison_destroy(pool->prison); |
| 1481 | dm_kcopyd_client_destroy(pool->copier); |
| 1482 | |
| 1483 | if (pool->wq) |
| 1484 | destroy_workqueue(pool->wq); |
| 1485 | |
| 1486 | if (pool->next_mapping) |
| 1487 | mempool_free(pool->next_mapping, pool->mapping_pool); |
| 1488 | mempool_destroy(pool->mapping_pool); |
| 1489 | mempool_destroy(pool->endio_hook_pool); |
| 1490 | kfree(pool); |
| 1491 | } |
| 1492 | |
| 1493 | static struct pool *pool_create(struct mapped_device *pool_md, |
| 1494 | struct block_device *metadata_dev, |
| 1495 | unsigned long block_size, char **error) |
| 1496 | { |
| 1497 | int r; |
| 1498 | void *err_p; |
| 1499 | struct pool *pool; |
| 1500 | struct dm_pool_metadata *pmd; |
| 1501 | |
| 1502 | pmd = dm_pool_metadata_open(metadata_dev, block_size); |
| 1503 | if (IS_ERR(pmd)) { |
| 1504 | *error = "Error creating metadata object"; |
| 1505 | return (struct pool *)pmd; |
| 1506 | } |
| 1507 | |
| 1508 | pool = kmalloc(sizeof(*pool), GFP_KERNEL); |
| 1509 | if (!pool) { |
| 1510 | *error = "Error allocating memory for pool"; |
| 1511 | err_p = ERR_PTR(-ENOMEM); |
| 1512 | goto bad_pool; |
| 1513 | } |
| 1514 | |
| 1515 | pool->pmd = pmd; |
| 1516 | pool->sectors_per_block = block_size; |
| 1517 | pool->block_shift = ffs(block_size) - 1; |
| 1518 | pool->offset_mask = block_size - 1; |
| 1519 | pool->low_water_blocks = 0; |
| 1520 | pool->zero_new_blocks = 1; |
| 1521 | pool->prison = prison_create(PRISON_CELLS); |
| 1522 | if (!pool->prison) { |
| 1523 | *error = "Error creating pool's bio prison"; |
| 1524 | err_p = ERR_PTR(-ENOMEM); |
| 1525 | goto bad_prison; |
| 1526 | } |
| 1527 | |
| 1528 | pool->copier = dm_kcopyd_client_create(); |
| 1529 | if (IS_ERR(pool->copier)) { |
| 1530 | r = PTR_ERR(pool->copier); |
| 1531 | *error = "Error creating pool's kcopyd client"; |
| 1532 | err_p = ERR_PTR(r); |
| 1533 | goto bad_kcopyd_client; |
| 1534 | } |
| 1535 | |
| 1536 | /* |
| 1537 | * Create singlethreaded workqueue that will service all devices |
| 1538 | * that use this metadata. |
| 1539 | */ |
| 1540 | pool->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM); |
| 1541 | if (!pool->wq) { |
| 1542 | *error = "Error creating pool's workqueue"; |
| 1543 | err_p = ERR_PTR(-ENOMEM); |
| 1544 | goto bad_wq; |
| 1545 | } |
| 1546 | |
| 1547 | INIT_WORK(&pool->worker, do_worker); |
| 1548 | spin_lock_init(&pool->lock); |
| 1549 | bio_list_init(&pool->deferred_bios); |
| 1550 | bio_list_init(&pool->deferred_flush_bios); |
| 1551 | INIT_LIST_HEAD(&pool->prepared_mappings); |
| 1552 | pool->low_water_triggered = 0; |
| 1553 | pool->no_free_space = 0; |
| 1554 | bio_list_init(&pool->retry_on_resume_list); |
| 1555 | ds_init(&pool->ds); |
| 1556 | |
| 1557 | pool->next_mapping = NULL; |
| 1558 | pool->mapping_pool = |
| 1559 | mempool_create_kmalloc_pool(MAPPING_POOL_SIZE, sizeof(struct new_mapping)); |
| 1560 | if (!pool->mapping_pool) { |
| 1561 | *error = "Error creating pool's mapping mempool"; |
| 1562 | err_p = ERR_PTR(-ENOMEM); |
| 1563 | goto bad_mapping_pool; |
| 1564 | } |
| 1565 | |
| 1566 | pool->endio_hook_pool = |
| 1567 | mempool_create_kmalloc_pool(ENDIO_HOOK_POOL_SIZE, sizeof(struct endio_hook)); |
| 1568 | if (!pool->endio_hook_pool) { |
| 1569 | *error = "Error creating pool's endio_hook mempool"; |
| 1570 | err_p = ERR_PTR(-ENOMEM); |
| 1571 | goto bad_endio_hook_pool; |
| 1572 | } |
| 1573 | pool->ref_count = 1; |
| 1574 | pool->pool_md = pool_md; |
| 1575 | pool->md_dev = metadata_dev; |
| 1576 | __pool_table_insert(pool); |
| 1577 | |
| 1578 | return pool; |
| 1579 | |
| 1580 | bad_endio_hook_pool: |
| 1581 | mempool_destroy(pool->mapping_pool); |
| 1582 | bad_mapping_pool: |
| 1583 | destroy_workqueue(pool->wq); |
| 1584 | bad_wq: |
| 1585 | dm_kcopyd_client_destroy(pool->copier); |
| 1586 | bad_kcopyd_client: |
| 1587 | prison_destroy(pool->prison); |
| 1588 | bad_prison: |
| 1589 | kfree(pool); |
| 1590 | bad_pool: |
| 1591 | if (dm_pool_metadata_close(pmd)) |
| 1592 | DMWARN("%s: dm_pool_metadata_close() failed.", __func__); |
| 1593 | |
| 1594 | return err_p; |
| 1595 | } |
| 1596 | |
| 1597 | static void __pool_inc(struct pool *pool) |
| 1598 | { |
| 1599 | BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); |
| 1600 | pool->ref_count++; |
| 1601 | } |
| 1602 | |
| 1603 | static void __pool_dec(struct pool *pool) |
| 1604 | { |
| 1605 | BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); |
| 1606 | BUG_ON(!pool->ref_count); |
| 1607 | if (!--pool->ref_count) |
| 1608 | __pool_destroy(pool); |
| 1609 | } |
| 1610 | |
| 1611 | static struct pool *__pool_find(struct mapped_device *pool_md, |
| 1612 | struct block_device *metadata_dev, |
| 1613 | unsigned long block_size, char **error) |
| 1614 | { |
| 1615 | struct pool *pool = __pool_table_lookup_metadata_dev(metadata_dev); |
| 1616 | |
| 1617 | if (pool) { |
| 1618 | if (pool->pool_md != pool_md) |
| 1619 | return ERR_PTR(-EBUSY); |
| 1620 | __pool_inc(pool); |
| 1621 | |
| 1622 | } else { |
| 1623 | pool = __pool_table_lookup(pool_md); |
| 1624 | if (pool) { |
| 1625 | if (pool->md_dev != metadata_dev) |
| 1626 | return ERR_PTR(-EINVAL); |
| 1627 | __pool_inc(pool); |
| 1628 | |
| 1629 | } else |
| 1630 | pool = pool_create(pool_md, metadata_dev, block_size, error); |
| 1631 | } |
| 1632 | |
| 1633 | return pool; |
| 1634 | } |
| 1635 | |
| 1636 | /*---------------------------------------------------------------- |
| 1637 | * Pool target methods |
| 1638 | *--------------------------------------------------------------*/ |
| 1639 | static void pool_dtr(struct dm_target *ti) |
| 1640 | { |
| 1641 | struct pool_c *pt = ti->private; |
| 1642 | |
| 1643 | mutex_lock(&dm_thin_pool_table.mutex); |
| 1644 | |
| 1645 | unbind_control_target(pt->pool, ti); |
| 1646 | __pool_dec(pt->pool); |
| 1647 | dm_put_device(ti, pt->metadata_dev); |
| 1648 | dm_put_device(ti, pt->data_dev); |
| 1649 | kfree(pt); |
| 1650 | |
| 1651 | mutex_unlock(&dm_thin_pool_table.mutex); |
| 1652 | } |
| 1653 | |
| 1654 | struct pool_features { |
| 1655 | unsigned zero_new_blocks:1; |
| 1656 | }; |
| 1657 | |
| 1658 | static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf, |
| 1659 | struct dm_target *ti) |
| 1660 | { |
| 1661 | int r; |
| 1662 | unsigned argc; |
| 1663 | const char *arg_name; |
| 1664 | |
| 1665 | static struct dm_arg _args[] = { |
| 1666 | {0, 1, "Invalid number of pool feature arguments"}, |
| 1667 | }; |
| 1668 | |
| 1669 | /* |
| 1670 | * No feature arguments supplied. |
| 1671 | */ |
| 1672 | if (!as->argc) |
| 1673 | return 0; |
| 1674 | |
| 1675 | r = dm_read_arg_group(_args, as, &argc, &ti->error); |
| 1676 | if (r) |
| 1677 | return -EINVAL; |
| 1678 | |
| 1679 | while (argc && !r) { |
| 1680 | arg_name = dm_shift_arg(as); |
| 1681 | argc--; |
| 1682 | |
| 1683 | if (!strcasecmp(arg_name, "skip_block_zeroing")) { |
| 1684 | pf->zero_new_blocks = 0; |
| 1685 | continue; |
| 1686 | } |
| 1687 | |
| 1688 | ti->error = "Unrecognised pool feature requested"; |
| 1689 | r = -EINVAL; |
| 1690 | } |
| 1691 | |
| 1692 | return r; |
| 1693 | } |
| 1694 | |
| 1695 | /* |
| 1696 | * thin-pool <metadata dev> <data dev> |
| 1697 | * <data block size (sectors)> |
| 1698 | * <low water mark (blocks)> |
| 1699 | * [<#feature args> [<arg>]*] |
| 1700 | * |
| 1701 | * Optional feature arguments are: |
| 1702 | * skip_block_zeroing: skips the zeroing of newly-provisioned blocks. |
| 1703 | */ |
| 1704 | static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv) |
| 1705 | { |
| 1706 | int r; |
| 1707 | struct pool_c *pt; |
| 1708 | struct pool *pool; |
| 1709 | struct pool_features pf; |
| 1710 | struct dm_arg_set as; |
| 1711 | struct dm_dev *data_dev; |
| 1712 | unsigned long block_size; |
| 1713 | dm_block_t low_water_blocks; |
| 1714 | struct dm_dev *metadata_dev; |
| 1715 | sector_t metadata_dev_size; |
| 1716 | |
| 1717 | /* |
| 1718 | * FIXME Remove validation from scope of lock. |
| 1719 | */ |
| 1720 | mutex_lock(&dm_thin_pool_table.mutex); |
| 1721 | |
| 1722 | if (argc < 4) { |
| 1723 | ti->error = "Invalid argument count"; |
| 1724 | r = -EINVAL; |
| 1725 | goto out_unlock; |
| 1726 | } |
| 1727 | as.argc = argc; |
| 1728 | as.argv = argv; |
| 1729 | |
| 1730 | r = dm_get_device(ti, argv[0], FMODE_READ | FMODE_WRITE, &metadata_dev); |
| 1731 | if (r) { |
| 1732 | ti->error = "Error opening metadata block device"; |
| 1733 | goto out_unlock; |
| 1734 | } |
| 1735 | |
| 1736 | metadata_dev_size = i_size_read(metadata_dev->bdev->bd_inode) >> SECTOR_SHIFT; |
| 1737 | if (metadata_dev_size > METADATA_DEV_MAX_SECTORS) { |
| 1738 | ti->error = "Metadata device is too large"; |
| 1739 | r = -EINVAL; |
| 1740 | goto out_metadata; |
| 1741 | } |
| 1742 | |
| 1743 | r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &data_dev); |
| 1744 | if (r) { |
| 1745 | ti->error = "Error getting data device"; |
| 1746 | goto out_metadata; |
| 1747 | } |
| 1748 | |
| 1749 | if (kstrtoul(argv[2], 10, &block_size) || !block_size || |
| 1750 | block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS || |
| 1751 | block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS || |
| 1752 | !is_power_of_2(block_size)) { |
| 1753 | ti->error = "Invalid block size"; |
| 1754 | r = -EINVAL; |
| 1755 | goto out; |
| 1756 | } |
| 1757 | |
| 1758 | if (kstrtoull(argv[3], 10, (unsigned long long *)&low_water_blocks)) { |
| 1759 | ti->error = "Invalid low water mark"; |
| 1760 | r = -EINVAL; |
| 1761 | goto out; |
| 1762 | } |
| 1763 | |
| 1764 | /* |
| 1765 | * Set default pool features. |
| 1766 | */ |
| 1767 | memset(&pf, 0, sizeof(pf)); |
| 1768 | pf.zero_new_blocks = 1; |
| 1769 | |
| 1770 | dm_consume_args(&as, 4); |
| 1771 | r = parse_pool_features(&as, &pf, ti); |
| 1772 | if (r) |
| 1773 | goto out; |
| 1774 | |
| 1775 | pt = kzalloc(sizeof(*pt), GFP_KERNEL); |
| 1776 | if (!pt) { |
| 1777 | r = -ENOMEM; |
| 1778 | goto out; |
| 1779 | } |
| 1780 | |
| 1781 | pool = __pool_find(dm_table_get_md(ti->table), metadata_dev->bdev, |
| 1782 | block_size, &ti->error); |
| 1783 | if (IS_ERR(pool)) { |
| 1784 | r = PTR_ERR(pool); |
| 1785 | goto out_free_pt; |
| 1786 | } |
| 1787 | |
| 1788 | pt->pool = pool; |
| 1789 | pt->ti = ti; |
| 1790 | pt->metadata_dev = metadata_dev; |
| 1791 | pt->data_dev = data_dev; |
| 1792 | pt->low_water_blocks = low_water_blocks; |
| 1793 | pt->zero_new_blocks = pf.zero_new_blocks; |
| 1794 | ti->num_flush_requests = 1; |
| 1795 | ti->num_discard_requests = 0; |
| 1796 | ti->private = pt; |
| 1797 | |
| 1798 | pt->callbacks.congested_fn = pool_is_congested; |
| 1799 | dm_table_add_target_callbacks(ti->table, &pt->callbacks); |
| 1800 | |
| 1801 | mutex_unlock(&dm_thin_pool_table.mutex); |
| 1802 | |
| 1803 | return 0; |
| 1804 | |
| 1805 | out_free_pt: |
| 1806 | kfree(pt); |
| 1807 | out: |
| 1808 | dm_put_device(ti, data_dev); |
| 1809 | out_metadata: |
| 1810 | dm_put_device(ti, metadata_dev); |
| 1811 | out_unlock: |
| 1812 | mutex_unlock(&dm_thin_pool_table.mutex); |
| 1813 | |
| 1814 | return r; |
| 1815 | } |
| 1816 | |
| 1817 | static int pool_map(struct dm_target *ti, struct bio *bio, |
| 1818 | union map_info *map_context) |
| 1819 | { |
| 1820 | int r; |
| 1821 | struct pool_c *pt = ti->private; |
| 1822 | struct pool *pool = pt->pool; |
| 1823 | unsigned long flags; |
| 1824 | |
| 1825 | /* |
| 1826 | * As this is a singleton target, ti->begin is always zero. |
| 1827 | */ |
| 1828 | spin_lock_irqsave(&pool->lock, flags); |
| 1829 | bio->bi_bdev = pt->data_dev->bdev; |
| 1830 | r = DM_MAPIO_REMAPPED; |
| 1831 | spin_unlock_irqrestore(&pool->lock, flags); |
| 1832 | |
| 1833 | return r; |
| 1834 | } |
| 1835 | |
| 1836 | /* |
| 1837 | * Retrieves the number of blocks of the data device from |
| 1838 | * the superblock and compares it to the actual device size, |
| 1839 | * thus resizing the data device in case it has grown. |
| 1840 | * |
| 1841 | * This both copes with opening preallocated data devices in the ctr |
| 1842 | * being followed by a resume |
| 1843 | * -and- |
| 1844 | * calling the resume method individually after userspace has |
| 1845 | * grown the data device in reaction to a table event. |
| 1846 | */ |
| 1847 | static int pool_preresume(struct dm_target *ti) |
| 1848 | { |
| 1849 | int r; |
| 1850 | struct pool_c *pt = ti->private; |
| 1851 | struct pool *pool = pt->pool; |
| 1852 | dm_block_t data_size, sb_data_size; |
| 1853 | |
| 1854 | /* |
| 1855 | * Take control of the pool object. |
| 1856 | */ |
| 1857 | r = bind_control_target(pool, ti); |
| 1858 | if (r) |
| 1859 | return r; |
| 1860 | |
| 1861 | data_size = ti->len >> pool->block_shift; |
| 1862 | r = dm_pool_get_data_dev_size(pool->pmd, &sb_data_size); |
| 1863 | if (r) { |
| 1864 | DMERR("failed to retrieve data device size"); |
| 1865 | return r; |
| 1866 | } |
| 1867 | |
| 1868 | if (data_size < sb_data_size) { |
| 1869 | DMERR("pool target too small, is %llu blocks (expected %llu)", |
| 1870 | data_size, sb_data_size); |
| 1871 | return -EINVAL; |
| 1872 | |
| 1873 | } else if (data_size > sb_data_size) { |
| 1874 | r = dm_pool_resize_data_dev(pool->pmd, data_size); |
| 1875 | if (r) { |
| 1876 | DMERR("failed to resize data device"); |
| 1877 | return r; |
| 1878 | } |
| 1879 | |
| 1880 | r = dm_pool_commit_metadata(pool->pmd); |
| 1881 | if (r) { |
| 1882 | DMERR("%s: dm_pool_commit_metadata() failed, error = %d", |
| 1883 | __func__, r); |
| 1884 | return r; |
| 1885 | } |
| 1886 | } |
| 1887 | |
| 1888 | return 0; |
| 1889 | } |
| 1890 | |
| 1891 | static void pool_resume(struct dm_target *ti) |
| 1892 | { |
| 1893 | struct pool_c *pt = ti->private; |
| 1894 | struct pool *pool = pt->pool; |
| 1895 | unsigned long flags; |
| 1896 | |
| 1897 | spin_lock_irqsave(&pool->lock, flags); |
| 1898 | pool->low_water_triggered = 0; |
| 1899 | pool->no_free_space = 0; |
| 1900 | __requeue_bios(pool); |
| 1901 | spin_unlock_irqrestore(&pool->lock, flags); |
| 1902 | |
| 1903 | wake_worker(pool); |
| 1904 | } |
| 1905 | |
| 1906 | static void pool_postsuspend(struct dm_target *ti) |
| 1907 | { |
| 1908 | int r; |
| 1909 | struct pool_c *pt = ti->private; |
| 1910 | struct pool *pool = pt->pool; |
| 1911 | |
| 1912 | flush_workqueue(pool->wq); |
| 1913 | |
| 1914 | r = dm_pool_commit_metadata(pool->pmd); |
| 1915 | if (r < 0) { |
| 1916 | DMERR("%s: dm_pool_commit_metadata() failed, error = %d", |
| 1917 | __func__, r); |
| 1918 | /* FIXME: invalidate device? error the next FUA or FLUSH bio ?*/ |
| 1919 | } |
| 1920 | } |
| 1921 | |
| 1922 | static int check_arg_count(unsigned argc, unsigned args_required) |
| 1923 | { |
| 1924 | if (argc != args_required) { |
| 1925 | DMWARN("Message received with %u arguments instead of %u.", |
| 1926 | argc, args_required); |
| 1927 | return -EINVAL; |
| 1928 | } |
| 1929 | |
| 1930 | return 0; |
| 1931 | } |
| 1932 | |
| 1933 | static int read_dev_id(char *arg, dm_thin_id *dev_id, int warning) |
| 1934 | { |
| 1935 | if (!kstrtoull(arg, 10, (unsigned long long *)dev_id) && |
| 1936 | *dev_id <= MAX_DEV_ID) |
| 1937 | return 0; |
| 1938 | |
| 1939 | if (warning) |
| 1940 | DMWARN("Message received with invalid device id: %s", arg); |
| 1941 | |
| 1942 | return -EINVAL; |
| 1943 | } |
| 1944 | |
| 1945 | static int process_create_thin_mesg(unsigned argc, char **argv, struct pool *pool) |
| 1946 | { |
| 1947 | dm_thin_id dev_id; |
| 1948 | int r; |
| 1949 | |
| 1950 | r = check_arg_count(argc, 2); |
| 1951 | if (r) |
| 1952 | return r; |
| 1953 | |
| 1954 | r = read_dev_id(argv[1], &dev_id, 1); |
| 1955 | if (r) |
| 1956 | return r; |
| 1957 | |
| 1958 | r = dm_pool_create_thin(pool->pmd, dev_id); |
| 1959 | if (r) { |
| 1960 | DMWARN("Creation of new thinly-provisioned device with id %s failed.", |
| 1961 | argv[1]); |
| 1962 | return r; |
| 1963 | } |
| 1964 | |
| 1965 | return 0; |
| 1966 | } |
| 1967 | |
| 1968 | static int process_create_snap_mesg(unsigned argc, char **argv, struct pool *pool) |
| 1969 | { |
| 1970 | dm_thin_id dev_id; |
| 1971 | dm_thin_id origin_dev_id; |
| 1972 | int r; |
| 1973 | |
| 1974 | r = check_arg_count(argc, 3); |
| 1975 | if (r) |
| 1976 | return r; |
| 1977 | |
| 1978 | r = read_dev_id(argv[1], &dev_id, 1); |
| 1979 | if (r) |
| 1980 | return r; |
| 1981 | |
| 1982 | r = read_dev_id(argv[2], &origin_dev_id, 1); |
| 1983 | if (r) |
| 1984 | return r; |
| 1985 | |
| 1986 | r = dm_pool_create_snap(pool->pmd, dev_id, origin_dev_id); |
| 1987 | if (r) { |
| 1988 | DMWARN("Creation of new snapshot %s of device %s failed.", |
| 1989 | argv[1], argv[2]); |
| 1990 | return r; |
| 1991 | } |
| 1992 | |
| 1993 | return 0; |
| 1994 | } |
| 1995 | |
| 1996 | static int process_delete_mesg(unsigned argc, char **argv, struct pool *pool) |
| 1997 | { |
| 1998 | dm_thin_id dev_id; |
| 1999 | int r; |
| 2000 | |
| 2001 | r = check_arg_count(argc, 2); |
| 2002 | if (r) |
| 2003 | return r; |
| 2004 | |
| 2005 | r = read_dev_id(argv[1], &dev_id, 1); |
| 2006 | if (r) |
| 2007 | return r; |
| 2008 | |
| 2009 | r = dm_pool_delete_thin_device(pool->pmd, dev_id); |
| 2010 | if (r) |
| 2011 | DMWARN("Deletion of thin device %s failed.", argv[1]); |
| 2012 | |
| 2013 | return r; |
| 2014 | } |
| 2015 | |
| 2016 | static int process_set_transaction_id_mesg(unsigned argc, char **argv, struct pool *pool) |
| 2017 | { |
| 2018 | dm_thin_id old_id, new_id; |
| 2019 | int r; |
| 2020 | |
| 2021 | r = check_arg_count(argc, 3); |
| 2022 | if (r) |
| 2023 | return r; |
| 2024 | |
| 2025 | if (kstrtoull(argv[1], 10, (unsigned long long *)&old_id)) { |
| 2026 | DMWARN("set_transaction_id message: Unrecognised id %s.", argv[1]); |
| 2027 | return -EINVAL; |
| 2028 | } |
| 2029 | |
| 2030 | if (kstrtoull(argv[2], 10, (unsigned long long *)&new_id)) { |
| 2031 | DMWARN("set_transaction_id message: Unrecognised new id %s.", argv[2]); |
| 2032 | return -EINVAL; |
| 2033 | } |
| 2034 | |
| 2035 | r = dm_pool_set_metadata_transaction_id(pool->pmd, old_id, new_id); |
| 2036 | if (r) { |
| 2037 | DMWARN("Failed to change transaction id from %s to %s.", |
| 2038 | argv[1], argv[2]); |
| 2039 | return r; |
| 2040 | } |
| 2041 | |
| 2042 | return 0; |
| 2043 | } |
| 2044 | |
| 2045 | /* |
| 2046 | * Messages supported: |
| 2047 | * create_thin <dev_id> |
| 2048 | * create_snap <dev_id> <origin_id> |
| 2049 | * delete <dev_id> |
| 2050 | * trim <dev_id> <new_size_in_sectors> |
| 2051 | * set_transaction_id <current_trans_id> <new_trans_id> |
| 2052 | */ |
| 2053 | static int pool_message(struct dm_target *ti, unsigned argc, char **argv) |
| 2054 | { |
| 2055 | int r = -EINVAL; |
| 2056 | struct pool_c *pt = ti->private; |
| 2057 | struct pool *pool = pt->pool; |
| 2058 | |
| 2059 | if (!strcasecmp(argv[0], "create_thin")) |
| 2060 | r = process_create_thin_mesg(argc, argv, pool); |
| 2061 | |
| 2062 | else if (!strcasecmp(argv[0], "create_snap")) |
| 2063 | r = process_create_snap_mesg(argc, argv, pool); |
| 2064 | |
| 2065 | else if (!strcasecmp(argv[0], "delete")) |
| 2066 | r = process_delete_mesg(argc, argv, pool); |
| 2067 | |
| 2068 | else if (!strcasecmp(argv[0], "set_transaction_id")) |
| 2069 | r = process_set_transaction_id_mesg(argc, argv, pool); |
| 2070 | |
| 2071 | else |
| 2072 | DMWARN("Unrecognised thin pool target message received: %s", argv[0]); |
| 2073 | |
| 2074 | if (!r) { |
| 2075 | r = dm_pool_commit_metadata(pool->pmd); |
| 2076 | if (r) |
| 2077 | DMERR("%s message: dm_pool_commit_metadata() failed, error = %d", |
| 2078 | argv[0], r); |
| 2079 | } |
| 2080 | |
| 2081 | return r; |
| 2082 | } |
| 2083 | |
| 2084 | /* |
| 2085 | * Status line is: |
| 2086 | * <transaction id> <used metadata sectors>/<total metadata sectors> |
| 2087 | * <used data sectors>/<total data sectors> <held metadata root> |
| 2088 | */ |
| 2089 | static int pool_status(struct dm_target *ti, status_type_t type, |
| 2090 | char *result, unsigned maxlen) |
| 2091 | { |
| 2092 | int r; |
| 2093 | unsigned sz = 0; |
| 2094 | uint64_t transaction_id; |
| 2095 | dm_block_t nr_free_blocks_data; |
| 2096 | dm_block_t nr_free_blocks_metadata; |
| 2097 | dm_block_t nr_blocks_data; |
| 2098 | dm_block_t nr_blocks_metadata; |
| 2099 | dm_block_t held_root; |
| 2100 | char buf[BDEVNAME_SIZE]; |
| 2101 | char buf2[BDEVNAME_SIZE]; |
| 2102 | struct pool_c *pt = ti->private; |
| 2103 | struct pool *pool = pt->pool; |
| 2104 | |
| 2105 | switch (type) { |
| 2106 | case STATUSTYPE_INFO: |
| 2107 | r = dm_pool_get_metadata_transaction_id(pool->pmd, |
| 2108 | &transaction_id); |
| 2109 | if (r) |
| 2110 | return r; |
| 2111 | |
| 2112 | r = dm_pool_get_free_metadata_block_count(pool->pmd, |
| 2113 | &nr_free_blocks_metadata); |
| 2114 | if (r) |
| 2115 | return r; |
| 2116 | |
| 2117 | r = dm_pool_get_metadata_dev_size(pool->pmd, &nr_blocks_metadata); |
| 2118 | if (r) |
| 2119 | return r; |
| 2120 | |
| 2121 | r = dm_pool_get_free_block_count(pool->pmd, |
| 2122 | &nr_free_blocks_data); |
| 2123 | if (r) |
| 2124 | return r; |
| 2125 | |
| 2126 | r = dm_pool_get_data_dev_size(pool->pmd, &nr_blocks_data); |
| 2127 | if (r) |
| 2128 | return r; |
| 2129 | |
| 2130 | r = dm_pool_get_held_metadata_root(pool->pmd, &held_root); |
| 2131 | if (r) |
| 2132 | return r; |
| 2133 | |
| 2134 | DMEMIT("%llu %llu/%llu %llu/%llu ", |
| 2135 | (unsigned long long)transaction_id, |
| 2136 | (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata), |
| 2137 | (unsigned long long)nr_blocks_metadata, |
| 2138 | (unsigned long long)(nr_blocks_data - nr_free_blocks_data), |
| 2139 | (unsigned long long)nr_blocks_data); |
| 2140 | |
| 2141 | if (held_root) |
| 2142 | DMEMIT("%llu", held_root); |
| 2143 | else |
| 2144 | DMEMIT("-"); |
| 2145 | |
| 2146 | break; |
| 2147 | |
| 2148 | case STATUSTYPE_TABLE: |
| 2149 | DMEMIT("%s %s %lu %llu ", |
| 2150 | format_dev_t(buf, pt->metadata_dev->bdev->bd_dev), |
| 2151 | format_dev_t(buf2, pt->data_dev->bdev->bd_dev), |
| 2152 | (unsigned long)pool->sectors_per_block, |
| 2153 | (unsigned long long)pt->low_water_blocks); |
| 2154 | |
| 2155 | DMEMIT("%u ", !pool->zero_new_blocks); |
| 2156 | |
| 2157 | if (!pool->zero_new_blocks) |
| 2158 | DMEMIT("skip_block_zeroing "); |
| 2159 | break; |
| 2160 | } |
| 2161 | |
| 2162 | return 0; |
| 2163 | } |
| 2164 | |
| 2165 | static int pool_iterate_devices(struct dm_target *ti, |
| 2166 | iterate_devices_callout_fn fn, void *data) |
| 2167 | { |
| 2168 | struct pool_c *pt = ti->private; |
| 2169 | |
| 2170 | return fn(ti, pt->data_dev, 0, ti->len, data); |
| 2171 | } |
| 2172 | |
| 2173 | static int pool_merge(struct dm_target *ti, struct bvec_merge_data *bvm, |
| 2174 | struct bio_vec *biovec, int max_size) |
| 2175 | { |
| 2176 | struct pool_c *pt = ti->private; |
| 2177 | struct request_queue *q = bdev_get_queue(pt->data_dev->bdev); |
| 2178 | |
| 2179 | if (!q->merge_bvec_fn) |
| 2180 | return max_size; |
| 2181 | |
| 2182 | bvm->bi_bdev = pt->data_dev->bdev; |
| 2183 | |
| 2184 | return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); |
| 2185 | } |
| 2186 | |
| 2187 | static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits) |
| 2188 | { |
| 2189 | struct pool_c *pt = ti->private; |
| 2190 | struct pool *pool = pt->pool; |
| 2191 | |
| 2192 | blk_limits_io_min(limits, 0); |
| 2193 | blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT); |
| 2194 | } |
| 2195 | |
| 2196 | static struct target_type pool_target = { |
| 2197 | .name = "thin-pool", |
| 2198 | .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE | |
| 2199 | DM_TARGET_IMMUTABLE, |
| 2200 | .version = {1, 0, 0}, |
| 2201 | .module = THIS_MODULE, |
| 2202 | .ctr = pool_ctr, |
| 2203 | .dtr = pool_dtr, |
| 2204 | .map = pool_map, |
| 2205 | .postsuspend = pool_postsuspend, |
| 2206 | .preresume = pool_preresume, |
| 2207 | .resume = pool_resume, |
| 2208 | .message = pool_message, |
| 2209 | .status = pool_status, |
| 2210 | .merge = pool_merge, |
| 2211 | .iterate_devices = pool_iterate_devices, |
| 2212 | .io_hints = pool_io_hints, |
| 2213 | }; |
| 2214 | |
| 2215 | /*---------------------------------------------------------------- |
| 2216 | * Thin target methods |
| 2217 | *--------------------------------------------------------------*/ |
| 2218 | static void thin_dtr(struct dm_target *ti) |
| 2219 | { |
| 2220 | struct thin_c *tc = ti->private; |
| 2221 | |
| 2222 | mutex_lock(&dm_thin_pool_table.mutex); |
| 2223 | |
| 2224 | __pool_dec(tc->pool); |
| 2225 | dm_pool_close_thin_device(tc->td); |
| 2226 | dm_put_device(ti, tc->pool_dev); |
| 2227 | kfree(tc); |
| 2228 | |
| 2229 | mutex_unlock(&dm_thin_pool_table.mutex); |
| 2230 | } |
| 2231 | |
| 2232 | /* |
| 2233 | * Thin target parameters: |
| 2234 | * |
| 2235 | * <pool_dev> <dev_id> |
| 2236 | * |
| 2237 | * pool_dev: the path to the pool (eg, /dev/mapper/my_pool) |
| 2238 | * dev_id: the internal device identifier |
| 2239 | */ |
| 2240 | static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv) |
| 2241 | { |
| 2242 | int r; |
| 2243 | struct thin_c *tc; |
| 2244 | struct dm_dev *pool_dev; |
| 2245 | struct mapped_device *pool_md; |
| 2246 | |
| 2247 | mutex_lock(&dm_thin_pool_table.mutex); |
| 2248 | |
| 2249 | if (argc != 2) { |
| 2250 | ti->error = "Invalid argument count"; |
| 2251 | r = -EINVAL; |
| 2252 | goto out_unlock; |
| 2253 | } |
| 2254 | |
| 2255 | tc = ti->private = kzalloc(sizeof(*tc), GFP_KERNEL); |
| 2256 | if (!tc) { |
| 2257 | ti->error = "Out of memory"; |
| 2258 | r = -ENOMEM; |
| 2259 | goto out_unlock; |
| 2260 | } |
| 2261 | |
| 2262 | r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &pool_dev); |
| 2263 | if (r) { |
| 2264 | ti->error = "Error opening pool device"; |
| 2265 | goto bad_pool_dev; |
| 2266 | } |
| 2267 | tc->pool_dev = pool_dev; |
| 2268 | |
| 2269 | if (read_dev_id(argv[1], (unsigned long long *)&tc->dev_id, 0)) { |
| 2270 | ti->error = "Invalid device id"; |
| 2271 | r = -EINVAL; |
| 2272 | goto bad_common; |
| 2273 | } |
| 2274 | |
| 2275 | pool_md = dm_get_md(tc->pool_dev->bdev->bd_dev); |
| 2276 | if (!pool_md) { |
| 2277 | ti->error = "Couldn't get pool mapped device"; |
| 2278 | r = -EINVAL; |
| 2279 | goto bad_common; |
| 2280 | } |
| 2281 | |
| 2282 | tc->pool = __pool_table_lookup(pool_md); |
| 2283 | if (!tc->pool) { |
| 2284 | ti->error = "Couldn't find pool object"; |
| 2285 | r = -EINVAL; |
| 2286 | goto bad_pool_lookup; |
| 2287 | } |
| 2288 | __pool_inc(tc->pool); |
| 2289 | |
| 2290 | r = dm_pool_open_thin_device(tc->pool->pmd, tc->dev_id, &tc->td); |
| 2291 | if (r) { |
| 2292 | ti->error = "Couldn't open thin internal device"; |
| 2293 | goto bad_thin_open; |
| 2294 | } |
| 2295 | |
| 2296 | ti->split_io = tc->pool->sectors_per_block; |
| 2297 | ti->num_flush_requests = 1; |
| 2298 | ti->num_discard_requests = 0; |
| 2299 | ti->discards_supported = 0; |
| 2300 | |
| 2301 | dm_put(pool_md); |
| 2302 | |
| 2303 | mutex_unlock(&dm_thin_pool_table.mutex); |
| 2304 | |
| 2305 | return 0; |
| 2306 | |
| 2307 | bad_thin_open: |
| 2308 | __pool_dec(tc->pool); |
| 2309 | bad_pool_lookup: |
| 2310 | dm_put(pool_md); |
| 2311 | bad_common: |
| 2312 | dm_put_device(ti, tc->pool_dev); |
| 2313 | bad_pool_dev: |
| 2314 | kfree(tc); |
| 2315 | out_unlock: |
| 2316 | mutex_unlock(&dm_thin_pool_table.mutex); |
| 2317 | |
| 2318 | return r; |
| 2319 | } |
| 2320 | |
| 2321 | static int thin_map(struct dm_target *ti, struct bio *bio, |
| 2322 | union map_info *map_context) |
| 2323 | { |
| 2324 | bio->bi_sector -= ti->begin; |
| 2325 | |
| 2326 | return thin_bio_map(ti, bio, map_context); |
| 2327 | } |
| 2328 | |
| 2329 | static void thin_postsuspend(struct dm_target *ti) |
| 2330 | { |
| 2331 | if (dm_noflush_suspending(ti)) |
| 2332 | requeue_io((struct thin_c *)ti->private); |
| 2333 | } |
| 2334 | |
| 2335 | /* |
| 2336 | * <nr mapped sectors> <highest mapped sector> |
| 2337 | */ |
| 2338 | static int thin_status(struct dm_target *ti, status_type_t type, |
| 2339 | char *result, unsigned maxlen) |
| 2340 | { |
| 2341 | int r; |
| 2342 | ssize_t sz = 0; |
| 2343 | dm_block_t mapped, highest; |
| 2344 | char buf[BDEVNAME_SIZE]; |
| 2345 | struct thin_c *tc = ti->private; |
| 2346 | |
| 2347 | if (!tc->td) |
| 2348 | DMEMIT("-"); |
| 2349 | else { |
| 2350 | switch (type) { |
| 2351 | case STATUSTYPE_INFO: |
| 2352 | r = dm_thin_get_mapped_count(tc->td, &mapped); |
| 2353 | if (r) |
| 2354 | return r; |
| 2355 | |
| 2356 | r = dm_thin_get_highest_mapped_block(tc->td, &highest); |
| 2357 | if (r < 0) |
| 2358 | return r; |
| 2359 | |
| 2360 | DMEMIT("%llu ", mapped * tc->pool->sectors_per_block); |
| 2361 | if (r) |
| 2362 | DMEMIT("%llu", ((highest + 1) * |
| 2363 | tc->pool->sectors_per_block) - 1); |
| 2364 | else |
| 2365 | DMEMIT("-"); |
| 2366 | break; |
| 2367 | |
| 2368 | case STATUSTYPE_TABLE: |
| 2369 | DMEMIT("%s %lu", |
| 2370 | format_dev_t(buf, tc->pool_dev->bdev->bd_dev), |
| 2371 | (unsigned long) tc->dev_id); |
| 2372 | break; |
| 2373 | } |
| 2374 | } |
| 2375 | |
| 2376 | return 0; |
| 2377 | } |
| 2378 | |
| 2379 | static int thin_iterate_devices(struct dm_target *ti, |
| 2380 | iterate_devices_callout_fn fn, void *data) |
| 2381 | { |
| 2382 | dm_block_t blocks; |
| 2383 | struct thin_c *tc = ti->private; |
| 2384 | |
| 2385 | /* |
| 2386 | * We can't call dm_pool_get_data_dev_size() since that blocks. So |
| 2387 | * we follow a more convoluted path through to the pool's target. |
| 2388 | */ |
| 2389 | if (!tc->pool->ti) |
| 2390 | return 0; /* nothing is bound */ |
| 2391 | |
| 2392 | blocks = tc->pool->ti->len >> tc->pool->block_shift; |
| 2393 | if (blocks) |
| 2394 | return fn(ti, tc->pool_dev, 0, tc->pool->sectors_per_block * blocks, data); |
| 2395 | |
| 2396 | return 0; |
| 2397 | } |
| 2398 | |
| 2399 | static void thin_io_hints(struct dm_target *ti, struct queue_limits *limits) |
| 2400 | { |
| 2401 | struct thin_c *tc = ti->private; |
| 2402 | |
| 2403 | blk_limits_io_min(limits, 0); |
| 2404 | blk_limits_io_opt(limits, tc->pool->sectors_per_block << SECTOR_SHIFT); |
| 2405 | } |
| 2406 | |
| 2407 | static struct target_type thin_target = { |
| 2408 | .name = "thin", |
| 2409 | .version = {1, 0, 0}, |
| 2410 | .module = THIS_MODULE, |
| 2411 | .ctr = thin_ctr, |
| 2412 | .dtr = thin_dtr, |
| 2413 | .map = thin_map, |
| 2414 | .postsuspend = thin_postsuspend, |
| 2415 | .status = thin_status, |
| 2416 | .iterate_devices = thin_iterate_devices, |
| 2417 | .io_hints = thin_io_hints, |
| 2418 | }; |
| 2419 | |
| 2420 | /*----------------------------------------------------------------*/ |
| 2421 | |
| 2422 | static int __init dm_thin_init(void) |
| 2423 | { |
| 2424 | int r; |
| 2425 | |
| 2426 | pool_table_init(); |
| 2427 | |
| 2428 | r = dm_register_target(&thin_target); |
| 2429 | if (r) |
| 2430 | return r; |
| 2431 | |
| 2432 | r = dm_register_target(&pool_target); |
| 2433 | if (r) |
| 2434 | dm_unregister_target(&thin_target); |
| 2435 | |
| 2436 | return r; |
| 2437 | } |
| 2438 | |
| 2439 | static void dm_thin_exit(void) |
| 2440 | { |
| 2441 | dm_unregister_target(&thin_target); |
| 2442 | dm_unregister_target(&pool_target); |
| 2443 | } |
| 2444 | |
| 2445 | module_init(dm_thin_init); |
| 2446 | module_exit(dm_thin_exit); |
| 2447 | |
| 2448 | MODULE_DESCRIPTION(DM_NAME "device-mapper thin provisioning target"); |
| 2449 | MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>"); |
| 2450 | MODULE_LICENSE("GPL"); |