Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * dm-snapshot.c |
| 3 | * |
| 4 | * Copyright (C) 2001-2002 Sistina Software (UK) Limited. |
| 5 | * |
| 6 | * This file is released under the GPL. |
| 7 | */ |
| 8 | |
| 9 | #include <linux/blkdev.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 10 | #include <linux/ctype.h> |
| 11 | #include <linux/device-mapper.h> |
| 12 | #include <linux/fs.h> |
| 13 | #include <linux/init.h> |
| 14 | #include <linux/kdev_t.h> |
| 15 | #include <linux/list.h> |
| 16 | #include <linux/mempool.h> |
| 17 | #include <linux/module.h> |
| 18 | #include <linux/slab.h> |
| 19 | #include <linux/vmalloc.h> |
vignesh babu | 6f3c3f0 | 2007-10-19 22:38:44 +0100 | [diff] [blame] | 20 | #include <linux/log2.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 21 | |
| 22 | #include "dm-snap.h" |
| 23 | #include "dm-bio-list.h" |
| 24 | #include "kcopyd.h" |
| 25 | |
Alasdair G Kergon | 72d9486 | 2006-06-26 00:27:35 -0700 | [diff] [blame] | 26 | #define DM_MSG_PREFIX "snapshots" |
| 27 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 28 | /* |
| 29 | * The percentage increment we will wake up users at |
| 30 | */ |
| 31 | #define WAKE_UP_PERCENT 5 |
| 32 | |
| 33 | /* |
| 34 | * kcopyd priority of snapshot operations |
| 35 | */ |
| 36 | #define SNAPSHOT_COPY_PRIORITY 2 |
| 37 | |
| 38 | /* |
| 39 | * Each snapshot reserves this many pages for io |
| 40 | */ |
| 41 | #define SNAPSHOT_PAGES 256 |
| 42 | |
Adrian Bunk | c642f9e | 2006-12-08 02:41:13 -0800 | [diff] [blame] | 43 | static struct workqueue_struct *ksnapd; |
David Howells | c402895 | 2006-11-22 14:57:56 +0000 | [diff] [blame] | 44 | static void flush_queued_bios(struct work_struct *work); |
Alasdair G Kergon | ca3a931 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 45 | |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 46 | struct dm_snap_pending_exception { |
| 47 | struct dm_snap_exception e; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 48 | |
| 49 | /* |
| 50 | * Origin buffers waiting for this to complete are held |
| 51 | * in a bio list |
| 52 | */ |
| 53 | struct bio_list origin_bios; |
| 54 | struct bio_list snapshot_bios; |
| 55 | |
| 56 | /* |
Alasdair G Kergon | eccf081 | 2006-03-27 01:17:42 -0800 | [diff] [blame] | 57 | * Short-term queue of pending exceptions prior to submission. |
| 58 | */ |
| 59 | struct list_head list; |
| 60 | |
| 61 | /* |
Alasdair G Kergon | b4b610f | 2006-03-27 01:17:44 -0800 | [diff] [blame] | 62 | * The primary pending_exception is the one that holds |
Alasdair G Kergon | 4b832e8 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 63 | * the ref_count and the list of origin_bios for a |
Alasdair G Kergon | b4b610f | 2006-03-27 01:17:44 -0800 | [diff] [blame] | 64 | * group of pending_exceptions. It is always last to get freed. |
| 65 | * These fields get set up when writing to the origin. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 66 | */ |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 67 | struct dm_snap_pending_exception *primary_pe; |
Alasdair G Kergon | b4b610f | 2006-03-27 01:17:44 -0800 | [diff] [blame] | 68 | |
| 69 | /* |
| 70 | * Number of pending_exceptions processing this chunk. |
| 71 | * When this drops to zero we must complete the origin bios. |
| 72 | * If incrementing or decrementing this, hold pe->snap->lock for |
| 73 | * the sibling concerned and not pe->primary_pe->snap->lock unless |
| 74 | * they are the same. |
| 75 | */ |
Alasdair G Kergon | 4b832e8 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 76 | atomic_t ref_count; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 77 | |
| 78 | /* Pointer back to snapshot context */ |
| 79 | struct dm_snapshot *snap; |
| 80 | |
| 81 | /* |
| 82 | * 1 indicates the exception has already been sent to |
| 83 | * kcopyd. |
| 84 | */ |
| 85 | int started; |
| 86 | }; |
| 87 | |
| 88 | /* |
| 89 | * Hash table mapping origin volumes to lists of snapshots and |
| 90 | * a lock to protect it |
| 91 | */ |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 92 | static struct kmem_cache *exception_cache; |
| 93 | static struct kmem_cache *pending_cache; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 94 | static mempool_t *pending_pool; |
| 95 | |
| 96 | /* |
| 97 | * One of these per registered origin, held in the snapshot_origins hash |
| 98 | */ |
| 99 | struct origin { |
| 100 | /* The origin device */ |
| 101 | struct block_device *bdev; |
| 102 | |
| 103 | struct list_head hash_list; |
| 104 | |
| 105 | /* List of snapshots for this origin */ |
| 106 | struct list_head snapshots; |
| 107 | }; |
| 108 | |
| 109 | /* |
| 110 | * Size of the hash table for origin volumes. If we make this |
| 111 | * the size of the minors list then it should be nearly perfect |
| 112 | */ |
| 113 | #define ORIGIN_HASH_SIZE 256 |
| 114 | #define ORIGIN_MASK 0xFF |
| 115 | static struct list_head *_origins; |
| 116 | static struct rw_semaphore _origins_lock; |
| 117 | |
| 118 | static int init_origin_hash(void) |
| 119 | { |
| 120 | int i; |
| 121 | |
| 122 | _origins = kmalloc(ORIGIN_HASH_SIZE * sizeof(struct list_head), |
| 123 | GFP_KERNEL); |
| 124 | if (!_origins) { |
Alasdair G Kergon | 72d9486 | 2006-06-26 00:27:35 -0700 | [diff] [blame] | 125 | DMERR("unable to allocate memory"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 126 | return -ENOMEM; |
| 127 | } |
| 128 | |
| 129 | for (i = 0; i < ORIGIN_HASH_SIZE; i++) |
| 130 | INIT_LIST_HEAD(_origins + i); |
| 131 | init_rwsem(&_origins_lock); |
| 132 | |
| 133 | return 0; |
| 134 | } |
| 135 | |
| 136 | static void exit_origin_hash(void) |
| 137 | { |
| 138 | kfree(_origins); |
| 139 | } |
| 140 | |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 141 | static unsigned origin_hash(struct block_device *bdev) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 142 | { |
| 143 | return bdev->bd_dev & ORIGIN_MASK; |
| 144 | } |
| 145 | |
| 146 | static struct origin *__lookup_origin(struct block_device *origin) |
| 147 | { |
| 148 | struct list_head *ol; |
| 149 | struct origin *o; |
| 150 | |
| 151 | ol = &_origins[origin_hash(origin)]; |
| 152 | list_for_each_entry (o, ol, hash_list) |
| 153 | if (bdev_equal(o->bdev, origin)) |
| 154 | return o; |
| 155 | |
| 156 | return NULL; |
| 157 | } |
| 158 | |
| 159 | static void __insert_origin(struct origin *o) |
| 160 | { |
| 161 | struct list_head *sl = &_origins[origin_hash(o->bdev)]; |
| 162 | list_add_tail(&o->hash_list, sl); |
| 163 | } |
| 164 | |
| 165 | /* |
| 166 | * Make a note of the snapshot and its origin so we can look it |
| 167 | * up when the origin has a write on it. |
| 168 | */ |
| 169 | static int register_snapshot(struct dm_snapshot *snap) |
| 170 | { |
| 171 | struct origin *o; |
| 172 | struct block_device *bdev = snap->origin->bdev; |
| 173 | |
| 174 | down_write(&_origins_lock); |
| 175 | o = __lookup_origin(bdev); |
| 176 | |
| 177 | if (!o) { |
| 178 | /* New origin */ |
| 179 | o = kmalloc(sizeof(*o), GFP_KERNEL); |
| 180 | if (!o) { |
| 181 | up_write(&_origins_lock); |
| 182 | return -ENOMEM; |
| 183 | } |
| 184 | |
| 185 | /* Initialise the struct */ |
| 186 | INIT_LIST_HEAD(&o->snapshots); |
| 187 | o->bdev = bdev; |
| 188 | |
| 189 | __insert_origin(o); |
| 190 | } |
| 191 | |
| 192 | list_add_tail(&snap->list, &o->snapshots); |
| 193 | |
| 194 | up_write(&_origins_lock); |
| 195 | return 0; |
| 196 | } |
| 197 | |
| 198 | static void unregister_snapshot(struct dm_snapshot *s) |
| 199 | { |
| 200 | struct origin *o; |
| 201 | |
| 202 | down_write(&_origins_lock); |
| 203 | o = __lookup_origin(s->origin->bdev); |
| 204 | |
| 205 | list_del(&s->list); |
| 206 | if (list_empty(&o->snapshots)) { |
| 207 | list_del(&o->hash_list); |
| 208 | kfree(o); |
| 209 | } |
| 210 | |
| 211 | up_write(&_origins_lock); |
| 212 | } |
| 213 | |
| 214 | /* |
| 215 | * Implementation of the exception hash tables. |
| 216 | */ |
| 217 | static int init_exception_table(struct exception_table *et, uint32_t size) |
| 218 | { |
| 219 | unsigned int i; |
| 220 | |
| 221 | et->hash_mask = size - 1; |
| 222 | et->table = dm_vcalloc(size, sizeof(struct list_head)); |
| 223 | if (!et->table) |
| 224 | return -ENOMEM; |
| 225 | |
| 226 | for (i = 0; i < size; i++) |
| 227 | INIT_LIST_HEAD(et->table + i); |
| 228 | |
| 229 | return 0; |
| 230 | } |
| 231 | |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 232 | static void exit_exception_table(struct exception_table *et, struct kmem_cache *mem) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 233 | { |
| 234 | struct list_head *slot; |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 235 | struct dm_snap_exception *ex, *next; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 236 | int i, size; |
| 237 | |
| 238 | size = et->hash_mask + 1; |
| 239 | for (i = 0; i < size; i++) { |
| 240 | slot = et->table + i; |
| 241 | |
| 242 | list_for_each_entry_safe (ex, next, slot, hash_list) |
| 243 | kmem_cache_free(mem, ex); |
| 244 | } |
| 245 | |
| 246 | vfree(et->table); |
| 247 | } |
| 248 | |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 249 | static uint32_t exception_hash(struct exception_table *et, chunk_t chunk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 250 | { |
| 251 | return chunk & et->hash_mask; |
| 252 | } |
| 253 | |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 254 | static void insert_exception(struct exception_table *eh, |
| 255 | struct dm_snap_exception *e) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 256 | { |
| 257 | struct list_head *l = &eh->table[exception_hash(eh, e->old_chunk)]; |
| 258 | list_add(&e->hash_list, l); |
| 259 | } |
| 260 | |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 261 | static void remove_exception(struct dm_snap_exception *e) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 262 | { |
| 263 | list_del(&e->hash_list); |
| 264 | } |
| 265 | |
| 266 | /* |
| 267 | * Return the exception data for a sector, or NULL if not |
| 268 | * remapped. |
| 269 | */ |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 270 | static struct dm_snap_exception *lookup_exception(struct exception_table *et, |
| 271 | chunk_t chunk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 272 | { |
| 273 | struct list_head *slot; |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 274 | struct dm_snap_exception *e; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 275 | |
| 276 | slot = &et->table[exception_hash(et, chunk)]; |
| 277 | list_for_each_entry (e, slot, hash_list) |
| 278 | if (e->old_chunk == chunk) |
| 279 | return e; |
| 280 | |
| 281 | return NULL; |
| 282 | } |
| 283 | |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 284 | static struct dm_snap_exception *alloc_exception(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 285 | { |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 286 | struct dm_snap_exception *e; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 287 | |
| 288 | e = kmem_cache_alloc(exception_cache, GFP_NOIO); |
| 289 | if (!e) |
| 290 | e = kmem_cache_alloc(exception_cache, GFP_ATOMIC); |
| 291 | |
| 292 | return e; |
| 293 | } |
| 294 | |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 295 | static void free_exception(struct dm_snap_exception *e) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 296 | { |
| 297 | kmem_cache_free(exception_cache, e); |
| 298 | } |
| 299 | |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 300 | static struct dm_snap_pending_exception *alloc_pending_exception(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 301 | { |
| 302 | return mempool_alloc(pending_pool, GFP_NOIO); |
| 303 | } |
| 304 | |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 305 | static void free_pending_exception(struct dm_snap_pending_exception *pe) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 306 | { |
| 307 | mempool_free(pe, pending_pool); |
| 308 | } |
| 309 | |
| 310 | int dm_add_exception(struct dm_snapshot *s, chunk_t old, chunk_t new) |
| 311 | { |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 312 | struct dm_snap_exception *e; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 313 | |
| 314 | e = alloc_exception(); |
| 315 | if (!e) |
| 316 | return -ENOMEM; |
| 317 | |
| 318 | e->old_chunk = old; |
| 319 | e->new_chunk = new; |
| 320 | insert_exception(&s->complete, e); |
| 321 | return 0; |
| 322 | } |
| 323 | |
| 324 | /* |
| 325 | * Hard coded magic. |
| 326 | */ |
| 327 | static int calc_max_buckets(void) |
| 328 | { |
| 329 | /* use a fixed size of 2MB */ |
| 330 | unsigned long mem = 2 * 1024 * 1024; |
| 331 | mem /= sizeof(struct list_head); |
| 332 | |
| 333 | return mem; |
| 334 | } |
| 335 | |
| 336 | /* |
| 337 | * Rounds a number down to a power of 2. |
| 338 | */ |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 339 | static uint32_t round_down(uint32_t n) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 340 | { |
| 341 | while (n & (n - 1)) |
| 342 | n &= (n - 1); |
| 343 | return n; |
| 344 | } |
| 345 | |
| 346 | /* |
| 347 | * Allocate room for a suitable hash table. |
| 348 | */ |
| 349 | static int init_hash_tables(struct dm_snapshot *s) |
| 350 | { |
| 351 | sector_t hash_size, cow_dev_size, origin_dev_size, max_buckets; |
| 352 | |
| 353 | /* |
| 354 | * Calculate based on the size of the original volume or |
| 355 | * the COW volume... |
| 356 | */ |
| 357 | cow_dev_size = get_dev_size(s->cow->bdev); |
| 358 | origin_dev_size = get_dev_size(s->origin->bdev); |
| 359 | max_buckets = calc_max_buckets(); |
| 360 | |
| 361 | hash_size = min(origin_dev_size, cow_dev_size) >> s->chunk_shift; |
| 362 | hash_size = min(hash_size, max_buckets); |
| 363 | |
| 364 | /* Round it down to a power of 2 */ |
| 365 | hash_size = round_down(hash_size); |
| 366 | if (init_exception_table(&s->complete, hash_size)) |
| 367 | return -ENOMEM; |
| 368 | |
| 369 | /* |
| 370 | * Allocate hash table for in-flight exceptions |
| 371 | * Make this smaller than the real hash table |
| 372 | */ |
| 373 | hash_size >>= 3; |
| 374 | if (hash_size < 64) |
| 375 | hash_size = 64; |
| 376 | |
| 377 | if (init_exception_table(&s->pending, hash_size)) { |
| 378 | exit_exception_table(&s->complete, exception_cache); |
| 379 | return -ENOMEM; |
| 380 | } |
| 381 | |
| 382 | return 0; |
| 383 | } |
| 384 | |
| 385 | /* |
| 386 | * Round a number up to the nearest 'size' boundary. size must |
| 387 | * be a power of 2. |
| 388 | */ |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 389 | static ulong round_up(ulong n, ulong size) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 390 | { |
| 391 | size--; |
| 392 | return (n + size) & ~size; |
| 393 | } |
| 394 | |
Mark McLoughlin | 4c7e3bf | 2006-10-03 01:15:25 -0700 | [diff] [blame] | 395 | static int set_chunk_size(struct dm_snapshot *s, const char *chunk_size_arg, |
| 396 | char **error) |
| 397 | { |
| 398 | unsigned long chunk_size; |
| 399 | char *value; |
| 400 | |
| 401 | chunk_size = simple_strtoul(chunk_size_arg, &value, 10); |
| 402 | if (*chunk_size_arg == '\0' || *value != '\0') { |
| 403 | *error = "Invalid chunk size"; |
| 404 | return -EINVAL; |
| 405 | } |
| 406 | |
| 407 | if (!chunk_size) { |
| 408 | s->chunk_size = s->chunk_mask = s->chunk_shift = 0; |
| 409 | return 0; |
| 410 | } |
| 411 | |
| 412 | /* |
| 413 | * Chunk size must be multiple of page size. Silently |
| 414 | * round up if it's not. |
| 415 | */ |
| 416 | chunk_size = round_up(chunk_size, PAGE_SIZE >> 9); |
| 417 | |
| 418 | /* Check chunk_size is a power of 2 */ |
vignesh babu | 6f3c3f0 | 2007-10-19 22:38:44 +0100 | [diff] [blame] | 419 | if (!is_power_of_2(chunk_size)) { |
Mark McLoughlin | 4c7e3bf | 2006-10-03 01:15:25 -0700 | [diff] [blame] | 420 | *error = "Chunk size is not a power of 2"; |
| 421 | return -EINVAL; |
| 422 | } |
| 423 | |
| 424 | /* Validate the chunk size against the device block size */ |
| 425 | if (chunk_size % (bdev_hardsect_size(s->cow->bdev) >> 9)) { |
| 426 | *error = "Chunk size is not a multiple of device blocksize"; |
| 427 | return -EINVAL; |
| 428 | } |
| 429 | |
| 430 | s->chunk_size = chunk_size; |
| 431 | s->chunk_mask = chunk_size - 1; |
| 432 | s->chunk_shift = ffs(chunk_size) - 1; |
| 433 | |
| 434 | return 0; |
| 435 | } |
| 436 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 437 | /* |
| 438 | * Construct a snapshot mapping: <origin_dev> <COW-dev> <p/n> <chunk-size> |
| 439 | */ |
| 440 | static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) |
| 441 | { |
| 442 | struct dm_snapshot *s; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 443 | int r = -EINVAL; |
| 444 | char persistent; |
| 445 | char *origin_path; |
| 446 | char *cow_path; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 447 | |
Mark McLoughlin | 4c7e3bf | 2006-10-03 01:15:25 -0700 | [diff] [blame] | 448 | if (argc != 4) { |
Alasdair G Kergon | 72d9486 | 2006-06-26 00:27:35 -0700 | [diff] [blame] | 449 | ti->error = "requires exactly 4 arguments"; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 450 | r = -EINVAL; |
| 451 | goto bad1; |
| 452 | } |
| 453 | |
| 454 | origin_path = argv[0]; |
| 455 | cow_path = argv[1]; |
| 456 | persistent = toupper(*argv[2]); |
| 457 | |
| 458 | if (persistent != 'P' && persistent != 'N') { |
| 459 | ti->error = "Persistent flag is not P or N"; |
| 460 | r = -EINVAL; |
| 461 | goto bad1; |
| 462 | } |
| 463 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 464 | s = kmalloc(sizeof(*s), GFP_KERNEL); |
| 465 | if (s == NULL) { |
| 466 | ti->error = "Cannot allocate snapshot context private " |
| 467 | "structure"; |
| 468 | r = -ENOMEM; |
| 469 | goto bad1; |
| 470 | } |
| 471 | |
| 472 | r = dm_get_device(ti, origin_path, 0, ti->len, FMODE_READ, &s->origin); |
| 473 | if (r) { |
| 474 | ti->error = "Cannot get origin device"; |
| 475 | goto bad2; |
| 476 | } |
| 477 | |
| 478 | r = dm_get_device(ti, cow_path, 0, 0, |
| 479 | FMODE_READ | FMODE_WRITE, &s->cow); |
| 480 | if (r) { |
| 481 | dm_put_device(ti, s->origin); |
| 482 | ti->error = "Cannot get COW device"; |
| 483 | goto bad2; |
| 484 | } |
| 485 | |
Mark McLoughlin | 4c7e3bf | 2006-10-03 01:15:25 -0700 | [diff] [blame] | 486 | r = set_chunk_size(s, argv[3], &ti->error); |
| 487 | if (r) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 488 | goto bad3; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 489 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 490 | s->type = persistent; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 491 | |
| 492 | s->valid = 1; |
Alasdair G Kergon | aa14ede | 2006-02-01 03:04:50 -0800 | [diff] [blame] | 493 | s->active = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 494 | s->last_percent = 0; |
| 495 | init_rwsem(&s->lock); |
Alasdair G Kergon | ca3a931 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 496 | spin_lock_init(&s->pe_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 497 | s->table = ti->table; |
| 498 | |
| 499 | /* Allocate hash table for COW data */ |
| 500 | if (init_hash_tables(s)) { |
| 501 | ti->error = "Unable to allocate hash table space"; |
| 502 | r = -ENOMEM; |
| 503 | goto bad3; |
| 504 | } |
| 505 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 506 | s->store.snap = s; |
| 507 | |
| 508 | if (persistent == 'P') |
Mark McLoughlin | 4c7e3bf | 2006-10-03 01:15:25 -0700 | [diff] [blame] | 509 | r = dm_create_persistent(&s->store); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 510 | else |
Mark McLoughlin | 4c7e3bf | 2006-10-03 01:15:25 -0700 | [diff] [blame] | 511 | r = dm_create_transient(&s->store); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 512 | |
| 513 | if (r) { |
| 514 | ti->error = "Couldn't create exception store"; |
| 515 | r = -EINVAL; |
| 516 | goto bad4; |
| 517 | } |
| 518 | |
| 519 | r = kcopyd_client_create(SNAPSHOT_PAGES, &s->kcopyd_client); |
| 520 | if (r) { |
| 521 | ti->error = "Could not create kcopyd client"; |
| 522 | goto bad5; |
| 523 | } |
| 524 | |
Alasdair G Kergon | aa14ede | 2006-02-01 03:04:50 -0800 | [diff] [blame] | 525 | /* Metadata must only be loaded into one table at once */ |
Mark McLoughlin | f9cea4f | 2006-10-03 01:15:25 -0700 | [diff] [blame] | 526 | r = s->store.read_metadata(&s->store); |
Milan Broz | 0764147 | 2007-07-12 17:28:13 +0100 | [diff] [blame] | 527 | if (r < 0) { |
Mark McLoughlin | f9cea4f | 2006-10-03 01:15:25 -0700 | [diff] [blame] | 528 | ti->error = "Failed to read snapshot metadata"; |
| 529 | goto bad6; |
Milan Broz | 0764147 | 2007-07-12 17:28:13 +0100 | [diff] [blame] | 530 | } else if (r > 0) { |
| 531 | s->valid = 0; |
| 532 | DMWARN("Snapshot is marked invalid."); |
Mark McLoughlin | f9cea4f | 2006-10-03 01:15:25 -0700 | [diff] [blame] | 533 | } |
Alasdair G Kergon | aa14ede | 2006-02-01 03:04:50 -0800 | [diff] [blame] | 534 | |
Alasdair G Kergon | ca3a931 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 535 | bio_list_init(&s->queued_bios); |
David Howells | c402895 | 2006-11-22 14:57:56 +0000 | [diff] [blame] | 536 | INIT_WORK(&s->queued_bios_work, flush_queued_bios); |
Alasdair G Kergon | ca3a931 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 537 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 538 | /* Add snapshot to the list of snapshots for this origin */ |
Alasdair G Kergon | aa14ede | 2006-02-01 03:04:50 -0800 | [diff] [blame] | 539 | /* Exceptions aren't triggered till snapshot_resume() is called */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 540 | if (register_snapshot(s)) { |
| 541 | r = -EINVAL; |
| 542 | ti->error = "Cannot register snapshot origin"; |
| 543 | goto bad6; |
| 544 | } |
| 545 | |
| 546 | ti->private = s; |
Alasdair G Kergon | c51c275 | 2006-06-26 00:27:18 -0700 | [diff] [blame] | 547 | ti->split_io = s->chunk_size; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 548 | |
| 549 | return 0; |
| 550 | |
| 551 | bad6: |
| 552 | kcopyd_client_destroy(s->kcopyd_client); |
| 553 | |
| 554 | bad5: |
| 555 | s->store.destroy(&s->store); |
| 556 | |
| 557 | bad4: |
| 558 | exit_exception_table(&s->pending, pending_cache); |
| 559 | exit_exception_table(&s->complete, exception_cache); |
| 560 | |
| 561 | bad3: |
| 562 | dm_put_device(ti, s->cow); |
| 563 | dm_put_device(ti, s->origin); |
| 564 | |
| 565 | bad2: |
| 566 | kfree(s); |
| 567 | |
| 568 | bad1: |
| 569 | return r; |
| 570 | } |
| 571 | |
Milan Broz | 31c93a0 | 2006-12-08 02:41:11 -0800 | [diff] [blame] | 572 | static void __free_exceptions(struct dm_snapshot *s) |
| 573 | { |
| 574 | kcopyd_client_destroy(s->kcopyd_client); |
| 575 | s->kcopyd_client = NULL; |
| 576 | |
| 577 | exit_exception_table(&s->pending, pending_cache); |
| 578 | exit_exception_table(&s->complete, exception_cache); |
| 579 | |
| 580 | s->store.destroy(&s->store); |
| 581 | } |
| 582 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 583 | static void snapshot_dtr(struct dm_target *ti) |
| 584 | { |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 585 | struct dm_snapshot *s = ti->private; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 586 | |
Alasdair G Kergon | ca3a931 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 587 | flush_workqueue(ksnapd); |
| 588 | |
Alasdair G Kergon | 138728dc | 2006-03-27 01:17:50 -0800 | [diff] [blame] | 589 | /* Prevent further origin writes from using this snapshot. */ |
| 590 | /* After this returns there can be no new kcopyd jobs. */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 591 | unregister_snapshot(s); |
| 592 | |
Milan Broz | 31c93a0 | 2006-12-08 02:41:11 -0800 | [diff] [blame] | 593 | __free_exceptions(s); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 594 | |
| 595 | dm_put_device(ti, s->origin); |
| 596 | dm_put_device(ti, s->cow); |
Alasdair G Kergon | 138728dc | 2006-03-27 01:17:50 -0800 | [diff] [blame] | 597 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 598 | kfree(s); |
| 599 | } |
| 600 | |
| 601 | /* |
| 602 | * Flush a list of buffers. |
| 603 | */ |
| 604 | static void flush_bios(struct bio *bio) |
| 605 | { |
| 606 | struct bio *n; |
| 607 | |
| 608 | while (bio) { |
| 609 | n = bio->bi_next; |
| 610 | bio->bi_next = NULL; |
| 611 | generic_make_request(bio); |
| 612 | bio = n; |
| 613 | } |
| 614 | } |
| 615 | |
David Howells | c402895 | 2006-11-22 14:57:56 +0000 | [diff] [blame] | 616 | static void flush_queued_bios(struct work_struct *work) |
Alasdair G Kergon | ca3a931 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 617 | { |
David Howells | c402895 | 2006-11-22 14:57:56 +0000 | [diff] [blame] | 618 | struct dm_snapshot *s = |
| 619 | container_of(work, struct dm_snapshot, queued_bios_work); |
Alasdair G Kergon | ca3a931 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 620 | struct bio *queued_bios; |
| 621 | unsigned long flags; |
| 622 | |
| 623 | spin_lock_irqsave(&s->pe_lock, flags); |
| 624 | queued_bios = bio_list_get(&s->queued_bios); |
| 625 | spin_unlock_irqrestore(&s->pe_lock, flags); |
| 626 | |
| 627 | flush_bios(queued_bios); |
| 628 | } |
| 629 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 630 | /* |
| 631 | * Error a list of buffers. |
| 632 | */ |
| 633 | static void error_bios(struct bio *bio) |
| 634 | { |
| 635 | struct bio *n; |
| 636 | |
| 637 | while (bio) { |
| 638 | n = bio->bi_next; |
| 639 | bio->bi_next = NULL; |
NeilBrown | 6712ecf | 2007-09-27 12:47:43 +0200 | [diff] [blame] | 640 | bio_io_error(bio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 641 | bio = n; |
| 642 | } |
| 643 | } |
| 644 | |
Alasdair G Kergon | 695368a | 2006-10-03 01:15:31 -0700 | [diff] [blame] | 645 | static void __invalidate_snapshot(struct dm_snapshot *s, int err) |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 646 | { |
| 647 | if (!s->valid) |
| 648 | return; |
| 649 | |
| 650 | if (err == -EIO) |
| 651 | DMERR("Invalidating snapshot: Error reading/writing."); |
| 652 | else if (err == -ENOMEM) |
| 653 | DMERR("Invalidating snapshot: Unable to allocate exception."); |
| 654 | |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 655 | if (s->store.drop_snapshot) |
| 656 | s->store.drop_snapshot(&s->store); |
| 657 | |
| 658 | s->valid = 0; |
| 659 | |
| 660 | dm_table_event(s->table); |
| 661 | } |
| 662 | |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 663 | static void get_pending_exception(struct dm_snap_pending_exception *pe) |
Alasdair G Kergon | 4b832e8 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 664 | { |
| 665 | atomic_inc(&pe->ref_count); |
| 666 | } |
| 667 | |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 668 | static struct bio *put_pending_exception(struct dm_snap_pending_exception *pe) |
Alasdair G Kergon | 4b832e8 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 669 | { |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 670 | struct dm_snap_pending_exception *primary_pe; |
Alasdair G Kergon | 4b832e8 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 671 | struct bio *origin_bios = NULL; |
| 672 | |
| 673 | primary_pe = pe->primary_pe; |
| 674 | |
| 675 | /* |
| 676 | * If this pe is involved in a write to the origin and |
| 677 | * it is the last sibling to complete then release |
| 678 | * the bios for the original write to the origin. |
| 679 | */ |
| 680 | if (primary_pe && |
| 681 | atomic_dec_and_test(&primary_pe->ref_count)) |
| 682 | origin_bios = bio_list_get(&primary_pe->origin_bios); |
| 683 | |
| 684 | /* |
| 685 | * Free the pe if it's not linked to an origin write or if |
| 686 | * it's not itself a primary pe. |
| 687 | */ |
| 688 | if (!primary_pe || primary_pe != pe) |
| 689 | free_pending_exception(pe); |
| 690 | |
| 691 | /* |
| 692 | * Free the primary pe if nothing references it. |
| 693 | */ |
| 694 | if (primary_pe && !atomic_read(&primary_pe->ref_count)) |
| 695 | free_pending_exception(primary_pe); |
| 696 | |
| 697 | return origin_bios; |
| 698 | } |
| 699 | |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 700 | static void pending_complete(struct dm_snap_pending_exception *pe, int success) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 701 | { |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 702 | struct dm_snap_exception *e; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 703 | struct dm_snapshot *s = pe->snap; |
Alasdair G Kergon | 9d493fa | 2006-10-03 01:15:29 -0700 | [diff] [blame] | 704 | struct bio *origin_bios = NULL; |
| 705 | struct bio *snapshot_bios = NULL; |
| 706 | int error = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 707 | |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 708 | if (!success) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 709 | /* Read/write error - snapshot is unusable */ |
| 710 | down_write(&s->lock); |
Alasdair G Kergon | 695368a | 2006-10-03 01:15:31 -0700 | [diff] [blame] | 711 | __invalidate_snapshot(s, -EIO); |
Alasdair G Kergon | 9d493fa | 2006-10-03 01:15:29 -0700 | [diff] [blame] | 712 | error = 1; |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 713 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 714 | } |
| 715 | |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 716 | e = alloc_exception(); |
| 717 | if (!e) { |
| 718 | down_write(&s->lock); |
Alasdair G Kergon | 695368a | 2006-10-03 01:15:31 -0700 | [diff] [blame] | 719 | __invalidate_snapshot(s, -ENOMEM); |
Alasdair G Kergon | 9d493fa | 2006-10-03 01:15:29 -0700 | [diff] [blame] | 720 | error = 1; |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 721 | goto out; |
| 722 | } |
| 723 | *e = pe->e; |
| 724 | |
Alasdair G Kergon | 9d493fa | 2006-10-03 01:15:29 -0700 | [diff] [blame] | 725 | down_write(&s->lock); |
| 726 | if (!s->valid) { |
| 727 | free_exception(e); |
| 728 | error = 1; |
| 729 | goto out; |
| 730 | } |
| 731 | |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 732 | /* |
| 733 | * Add a proper exception, and remove the |
| 734 | * in-flight exception from the list. |
| 735 | */ |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 736 | insert_exception(&s->complete, e); |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 737 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 738 | out: |
Alasdair G Kergon | 695368a | 2006-10-03 01:15:31 -0700 | [diff] [blame] | 739 | remove_exception(&pe->e); |
Alasdair G Kergon | 9d493fa | 2006-10-03 01:15:29 -0700 | [diff] [blame] | 740 | snapshot_bios = bio_list_get(&pe->snapshot_bios); |
Alasdair G Kergon | 4b832e8 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 741 | origin_bios = put_pending_exception(pe); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 742 | |
Alasdair G Kergon | 9d493fa | 2006-10-03 01:15:29 -0700 | [diff] [blame] | 743 | up_write(&s->lock); |
| 744 | |
| 745 | /* Submit any pending write bios */ |
| 746 | if (error) |
| 747 | error_bios(snapshot_bios); |
| 748 | else |
| 749 | flush_bios(snapshot_bios); |
| 750 | |
| 751 | flush_bios(origin_bios); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 752 | } |
| 753 | |
| 754 | static void commit_callback(void *context, int success) |
| 755 | { |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 756 | struct dm_snap_pending_exception *pe = context; |
| 757 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 758 | pending_complete(pe, success); |
| 759 | } |
| 760 | |
| 761 | /* |
| 762 | * Called when the copy I/O has finished. kcopyd actually runs |
| 763 | * this code so don't block. |
| 764 | */ |
| 765 | static void copy_callback(int read_err, unsigned int write_err, void *context) |
| 766 | { |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 767 | struct dm_snap_pending_exception *pe = context; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 768 | struct dm_snapshot *s = pe->snap; |
| 769 | |
| 770 | if (read_err || write_err) |
| 771 | pending_complete(pe, 0); |
| 772 | |
| 773 | else |
| 774 | /* Update the metadata if we are persistent */ |
| 775 | s->store.commit_exception(&s->store, &pe->e, commit_callback, |
| 776 | pe); |
| 777 | } |
| 778 | |
| 779 | /* |
| 780 | * Dispatches the copy operation to kcopyd. |
| 781 | */ |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 782 | static void start_copy(struct dm_snap_pending_exception *pe) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 783 | { |
| 784 | struct dm_snapshot *s = pe->snap; |
| 785 | struct io_region src, dest; |
| 786 | struct block_device *bdev = s->origin->bdev; |
| 787 | sector_t dev_size; |
| 788 | |
| 789 | dev_size = get_dev_size(bdev); |
| 790 | |
| 791 | src.bdev = bdev; |
| 792 | src.sector = chunk_to_sector(s, pe->e.old_chunk); |
| 793 | src.count = min(s->chunk_size, dev_size - src.sector); |
| 794 | |
| 795 | dest.bdev = s->cow->bdev; |
| 796 | dest.sector = chunk_to_sector(s, pe->e.new_chunk); |
| 797 | dest.count = src.count; |
| 798 | |
| 799 | /* Hand over to kcopyd */ |
| 800 | kcopyd_copy(s->kcopyd_client, |
| 801 | &src, 1, &dest, 0, copy_callback, pe); |
| 802 | } |
| 803 | |
| 804 | /* |
| 805 | * Looks to see if this snapshot already has a pending exception |
| 806 | * for this chunk, otherwise it allocates a new one and inserts |
| 807 | * it into the pending table. |
| 808 | * |
| 809 | * NOTE: a write lock must be held on snap->lock before calling |
| 810 | * this. |
| 811 | */ |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 812 | static struct dm_snap_pending_exception * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 813 | __find_pending_exception(struct dm_snapshot *s, struct bio *bio) |
| 814 | { |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 815 | struct dm_snap_exception *e; |
| 816 | struct dm_snap_pending_exception *pe; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 817 | chunk_t chunk = sector_to_chunk(s, bio->bi_sector); |
| 818 | |
| 819 | /* |
| 820 | * Is there a pending exception for this already ? |
| 821 | */ |
| 822 | e = lookup_exception(&s->pending, chunk); |
| 823 | if (e) { |
| 824 | /* cast the exception to a pending exception */ |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 825 | pe = container_of(e, struct dm_snap_pending_exception, e); |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 826 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 827 | } |
| 828 | |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 829 | /* |
| 830 | * Create a new pending exception, we don't want |
| 831 | * to hold the lock while we do this. |
| 832 | */ |
| 833 | up_write(&s->lock); |
| 834 | pe = alloc_pending_exception(); |
| 835 | down_write(&s->lock); |
| 836 | |
| 837 | if (!s->valid) { |
| 838 | free_pending_exception(pe); |
| 839 | return NULL; |
| 840 | } |
| 841 | |
| 842 | e = lookup_exception(&s->pending, chunk); |
| 843 | if (e) { |
| 844 | free_pending_exception(pe); |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 845 | pe = container_of(e, struct dm_snap_pending_exception, e); |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 846 | goto out; |
| 847 | } |
| 848 | |
| 849 | pe->e.old_chunk = chunk; |
| 850 | bio_list_init(&pe->origin_bios); |
| 851 | bio_list_init(&pe->snapshot_bios); |
| 852 | pe->primary_pe = NULL; |
Alasdair G Kergon | 4b832e8 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 853 | atomic_set(&pe->ref_count, 0); |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 854 | pe->snap = s; |
| 855 | pe->started = 0; |
| 856 | |
| 857 | if (s->store.prepare_exception(&s->store, &pe->e)) { |
| 858 | free_pending_exception(pe); |
| 859 | return NULL; |
| 860 | } |
| 861 | |
Alasdair G Kergon | 4b832e8 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 862 | get_pending_exception(pe); |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 863 | insert_exception(&s->pending, &pe->e); |
| 864 | |
| 865 | out: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 866 | return pe; |
| 867 | } |
| 868 | |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 869 | static void remap_exception(struct dm_snapshot *s, struct dm_snap_exception *e, |
| 870 | struct bio *bio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 871 | { |
| 872 | bio->bi_bdev = s->cow->bdev; |
| 873 | bio->bi_sector = chunk_to_sector(s, e->new_chunk) + |
| 874 | (bio->bi_sector & s->chunk_mask); |
| 875 | } |
| 876 | |
| 877 | static int snapshot_map(struct dm_target *ti, struct bio *bio, |
| 878 | union map_info *map_context) |
| 879 | { |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 880 | struct dm_snap_exception *e; |
| 881 | struct dm_snapshot *s = ti->private; |
Kiyoshi Ueda | d2a7ad2 | 2006-12-08 02:41:06 -0800 | [diff] [blame] | 882 | int r = DM_MAPIO_REMAPPED; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 883 | chunk_t chunk; |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 884 | struct dm_snap_pending_exception *pe = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 885 | |
| 886 | chunk = sector_to_chunk(s, bio->bi_sector); |
| 887 | |
| 888 | /* Full snapshots are not usable */ |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 889 | /* To get here the table must be live so s->active is always set. */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 890 | if (!s->valid) |
Alasdair G Kergon | f6a80ea | 2005-07-12 15:53:01 -0700 | [diff] [blame] | 891 | return -EIO; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 892 | |
Alasdair G Kergon | ba40a2a | 2006-10-03 01:15:28 -0700 | [diff] [blame] | 893 | /* FIXME: should only take write lock if we need |
| 894 | * to copy an exception */ |
| 895 | down_write(&s->lock); |
| 896 | |
| 897 | if (!s->valid) { |
| 898 | r = -EIO; |
| 899 | goto out_unlock; |
| 900 | } |
| 901 | |
| 902 | /* If the block is already remapped - use that, else remap it */ |
| 903 | e = lookup_exception(&s->complete, chunk); |
| 904 | if (e) { |
| 905 | remap_exception(s, e, bio); |
| 906 | goto out_unlock; |
| 907 | } |
| 908 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 909 | /* |
| 910 | * Write to snapshot - higher level takes care of RW/RO |
| 911 | * flags so we should only get this if we are |
| 912 | * writeable. |
| 913 | */ |
| 914 | if (bio_rw(bio) == WRITE) { |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 915 | pe = __find_pending_exception(s, bio); |
| 916 | if (!pe) { |
Alasdair G Kergon | 695368a | 2006-10-03 01:15:31 -0700 | [diff] [blame] | 917 | __invalidate_snapshot(s, -ENOMEM); |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 918 | r = -EIO; |
| 919 | goto out_unlock; |
| 920 | } |
| 921 | |
| 922 | remap_exception(s, &pe->e, bio); |
| 923 | bio_list_add(&pe->snapshot_bios, bio); |
| 924 | |
Kiyoshi Ueda | d2a7ad2 | 2006-12-08 02:41:06 -0800 | [diff] [blame] | 925 | r = DM_MAPIO_SUBMITTED; |
Alasdair G Kergon | ba40a2a | 2006-10-03 01:15:28 -0700 | [diff] [blame] | 926 | |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 927 | if (!pe->started) { |
| 928 | /* this is protected by snap->lock */ |
| 929 | pe->started = 1; |
Alasdair G Kergon | ba40a2a | 2006-10-03 01:15:28 -0700 | [diff] [blame] | 930 | up_write(&s->lock); |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 931 | start_copy(pe); |
Alasdair G Kergon | ba40a2a | 2006-10-03 01:15:28 -0700 | [diff] [blame] | 932 | goto out; |
| 933 | } |
| 934 | } else |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 935 | /* |
| 936 | * FIXME: this read path scares me because we |
| 937 | * always use the origin when we have a pending |
| 938 | * exception. However I can't think of a |
| 939 | * situation where this is wrong - ejt. |
| 940 | */ |
Alasdair G Kergon | ba40a2a | 2006-10-03 01:15:28 -0700 | [diff] [blame] | 941 | bio->bi_bdev = s->origin->bdev; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 942 | |
Alasdair G Kergon | ba40a2a | 2006-10-03 01:15:28 -0700 | [diff] [blame] | 943 | out_unlock: |
| 944 | up_write(&s->lock); |
| 945 | out: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 946 | return r; |
| 947 | } |
| 948 | |
| 949 | static void snapshot_resume(struct dm_target *ti) |
| 950 | { |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 951 | struct dm_snapshot *s = ti->private; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 952 | |
Alasdair G Kergon | aa14ede | 2006-02-01 03:04:50 -0800 | [diff] [blame] | 953 | down_write(&s->lock); |
| 954 | s->active = 1; |
| 955 | up_write(&s->lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 956 | } |
| 957 | |
| 958 | static int snapshot_status(struct dm_target *ti, status_type_t type, |
| 959 | char *result, unsigned int maxlen) |
| 960 | { |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 961 | struct dm_snapshot *snap = ti->private; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 962 | |
| 963 | switch (type) { |
| 964 | case STATUSTYPE_INFO: |
| 965 | if (!snap->valid) |
| 966 | snprintf(result, maxlen, "Invalid"); |
| 967 | else { |
| 968 | if (snap->store.fraction_full) { |
| 969 | sector_t numerator, denominator; |
| 970 | snap->store.fraction_full(&snap->store, |
| 971 | &numerator, |
| 972 | &denominator); |
Andrew Morton | 4ee218c | 2006-03-27 01:17:48 -0800 | [diff] [blame] | 973 | snprintf(result, maxlen, "%llu/%llu", |
| 974 | (unsigned long long)numerator, |
| 975 | (unsigned long long)denominator); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 976 | } |
| 977 | else |
| 978 | snprintf(result, maxlen, "Unknown"); |
| 979 | } |
| 980 | break; |
| 981 | |
| 982 | case STATUSTYPE_TABLE: |
| 983 | /* |
| 984 | * kdevname returns a static pointer so we need |
| 985 | * to make private copies if the output is to |
| 986 | * make sense. |
| 987 | */ |
Andrew Morton | 4ee218c | 2006-03-27 01:17:48 -0800 | [diff] [blame] | 988 | snprintf(result, maxlen, "%s %s %c %llu", |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 989 | snap->origin->name, snap->cow->name, |
Andrew Morton | 4ee218c | 2006-03-27 01:17:48 -0800 | [diff] [blame] | 990 | snap->type, |
| 991 | (unsigned long long)snap->chunk_size); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 992 | break; |
| 993 | } |
| 994 | |
| 995 | return 0; |
| 996 | } |
| 997 | |
| 998 | /*----------------------------------------------------------------- |
| 999 | * Origin methods |
| 1000 | *---------------------------------------------------------------*/ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1001 | static int __origin_write(struct list_head *snapshots, struct bio *bio) |
| 1002 | { |
Kiyoshi Ueda | d2a7ad2 | 2006-12-08 02:41:06 -0800 | [diff] [blame] | 1003 | int r = DM_MAPIO_REMAPPED, first = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1004 | struct dm_snapshot *snap; |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 1005 | struct dm_snap_exception *e; |
| 1006 | struct dm_snap_pending_exception *pe, *next_pe, *primary_pe = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1007 | chunk_t chunk; |
Alasdair G Kergon | eccf081 | 2006-03-27 01:17:42 -0800 | [diff] [blame] | 1008 | LIST_HEAD(pe_queue); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1009 | |
| 1010 | /* Do all the snapshots on this origin */ |
| 1011 | list_for_each_entry (snap, snapshots, list) { |
| 1012 | |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 1013 | down_write(&snap->lock); |
| 1014 | |
Alasdair G Kergon | aa14ede | 2006-02-01 03:04:50 -0800 | [diff] [blame] | 1015 | /* Only deal with valid and active snapshots */ |
| 1016 | if (!snap->valid || !snap->active) |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 1017 | goto next_snapshot; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1018 | |
Alasdair G Kergon | d5e404c | 2005-07-12 15:53:05 -0700 | [diff] [blame] | 1019 | /* Nothing to do if writing beyond end of snapshot */ |
| 1020 | if (bio->bi_sector >= dm_table_get_size(snap->table)) |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 1021 | goto next_snapshot; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1022 | |
| 1023 | /* |
| 1024 | * Remember, different snapshots can have |
| 1025 | * different chunk sizes. |
| 1026 | */ |
| 1027 | chunk = sector_to_chunk(snap, bio->bi_sector); |
| 1028 | |
| 1029 | /* |
| 1030 | * Check exception table to see if block |
| 1031 | * is already remapped in this snapshot |
| 1032 | * and trigger an exception if not. |
Alasdair G Kergon | b4b610f | 2006-03-27 01:17:44 -0800 | [diff] [blame] | 1033 | * |
Alasdair G Kergon | 4b832e8 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 1034 | * ref_count is initialised to 1 so pending_complete() |
Alasdair G Kergon | b4b610f | 2006-03-27 01:17:44 -0800 | [diff] [blame] | 1035 | * won't destroy the primary_pe while we're inside this loop. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1036 | */ |
| 1037 | e = lookup_exception(&snap->complete, chunk); |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 1038 | if (e) |
| 1039 | goto next_snapshot; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1040 | |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 1041 | pe = __find_pending_exception(snap, bio); |
| 1042 | if (!pe) { |
Alasdair G Kergon | 695368a | 2006-10-03 01:15:31 -0700 | [diff] [blame] | 1043 | __invalidate_snapshot(snap, -ENOMEM); |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 1044 | goto next_snapshot; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1045 | } |
| 1046 | |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 1047 | if (!primary_pe) { |
| 1048 | /* |
| 1049 | * Either every pe here has same |
| 1050 | * primary_pe or none has one yet. |
| 1051 | */ |
| 1052 | if (pe->primary_pe) |
| 1053 | primary_pe = pe->primary_pe; |
| 1054 | else { |
| 1055 | primary_pe = pe; |
| 1056 | first = 1; |
| 1057 | } |
| 1058 | |
| 1059 | bio_list_add(&primary_pe->origin_bios, bio); |
| 1060 | |
Kiyoshi Ueda | d2a7ad2 | 2006-12-08 02:41:06 -0800 | [diff] [blame] | 1061 | r = DM_MAPIO_SUBMITTED; |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 1062 | } |
| 1063 | |
| 1064 | if (!pe->primary_pe) { |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 1065 | pe->primary_pe = primary_pe; |
Alasdair G Kergon | 4b832e8 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 1066 | get_pending_exception(primary_pe); |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 1067 | } |
| 1068 | |
| 1069 | if (!pe->started) { |
| 1070 | pe->started = 1; |
| 1071 | list_add_tail(&pe->list, &pe_queue); |
| 1072 | } |
| 1073 | |
| 1074 | next_snapshot: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1075 | up_write(&snap->lock); |
| 1076 | } |
| 1077 | |
Alasdair G Kergon | b4b610f | 2006-03-27 01:17:44 -0800 | [diff] [blame] | 1078 | if (!primary_pe) |
Alasdair G Kergon | 4b832e8 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 1079 | return r; |
Alasdair G Kergon | b4b610f | 2006-03-27 01:17:44 -0800 | [diff] [blame] | 1080 | |
| 1081 | /* |
| 1082 | * If this is the first time we're processing this chunk and |
Alasdair G Kergon | 4b832e8 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 1083 | * ref_count is now 1 it means all the pending exceptions |
Alasdair G Kergon | b4b610f | 2006-03-27 01:17:44 -0800 | [diff] [blame] | 1084 | * got completed while we were in the loop above, so it falls to |
| 1085 | * us here to remove the primary_pe and submit any origin_bios. |
| 1086 | */ |
| 1087 | |
Alasdair G Kergon | 4b832e8 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 1088 | if (first && atomic_dec_and_test(&primary_pe->ref_count)) { |
Alasdair G Kergon | b4b610f | 2006-03-27 01:17:44 -0800 | [diff] [blame] | 1089 | flush_bios(bio_list_get(&primary_pe->origin_bios)); |
| 1090 | free_pending_exception(primary_pe); |
| 1091 | /* If we got here, pe_queue is necessarily empty. */ |
Alasdair G Kergon | 4b832e8 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 1092 | return r; |
Alasdair G Kergon | b4b610f | 2006-03-27 01:17:44 -0800 | [diff] [blame] | 1093 | } |
| 1094 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1095 | /* |
| 1096 | * Now that we have a complete pe list we can start the copying. |
| 1097 | */ |
Alasdair G Kergon | eccf081 | 2006-03-27 01:17:42 -0800 | [diff] [blame] | 1098 | list_for_each_entry_safe(pe, next_pe, &pe_queue, list) |
| 1099 | start_copy(pe); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1100 | |
| 1101 | return r; |
| 1102 | } |
| 1103 | |
| 1104 | /* |
| 1105 | * Called on a write from the origin driver. |
| 1106 | */ |
| 1107 | static int do_origin(struct dm_dev *origin, struct bio *bio) |
| 1108 | { |
| 1109 | struct origin *o; |
Kiyoshi Ueda | d2a7ad2 | 2006-12-08 02:41:06 -0800 | [diff] [blame] | 1110 | int r = DM_MAPIO_REMAPPED; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1111 | |
| 1112 | down_read(&_origins_lock); |
| 1113 | o = __lookup_origin(origin->bdev); |
| 1114 | if (o) |
| 1115 | r = __origin_write(&o->snapshots, bio); |
| 1116 | up_read(&_origins_lock); |
| 1117 | |
| 1118 | return r; |
| 1119 | } |
| 1120 | |
| 1121 | /* |
| 1122 | * Origin: maps a linear range of a device, with hooks for snapshotting. |
| 1123 | */ |
| 1124 | |
| 1125 | /* |
| 1126 | * Construct an origin mapping: <dev_path> |
| 1127 | * The context for an origin is merely a 'struct dm_dev *' |
| 1128 | * pointing to the real device. |
| 1129 | */ |
| 1130 | static int origin_ctr(struct dm_target *ti, unsigned int argc, char **argv) |
| 1131 | { |
| 1132 | int r; |
| 1133 | struct dm_dev *dev; |
| 1134 | |
| 1135 | if (argc != 1) { |
Alasdair G Kergon | 72d9486 | 2006-06-26 00:27:35 -0700 | [diff] [blame] | 1136 | ti->error = "origin: incorrect number of arguments"; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1137 | return -EINVAL; |
| 1138 | } |
| 1139 | |
| 1140 | r = dm_get_device(ti, argv[0], 0, ti->len, |
| 1141 | dm_table_get_mode(ti->table), &dev); |
| 1142 | if (r) { |
| 1143 | ti->error = "Cannot get target device"; |
| 1144 | return r; |
| 1145 | } |
| 1146 | |
| 1147 | ti->private = dev; |
| 1148 | return 0; |
| 1149 | } |
| 1150 | |
| 1151 | static void origin_dtr(struct dm_target *ti) |
| 1152 | { |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 1153 | struct dm_dev *dev = ti->private; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1154 | dm_put_device(ti, dev); |
| 1155 | } |
| 1156 | |
| 1157 | static int origin_map(struct dm_target *ti, struct bio *bio, |
| 1158 | union map_info *map_context) |
| 1159 | { |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 1160 | struct dm_dev *dev = ti->private; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1161 | bio->bi_bdev = dev->bdev; |
| 1162 | |
| 1163 | /* Only tell snapshots if this is a write */ |
Kiyoshi Ueda | d2a7ad2 | 2006-12-08 02:41:06 -0800 | [diff] [blame] | 1164 | return (bio_rw(bio) == WRITE) ? do_origin(dev, bio) : DM_MAPIO_REMAPPED; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1165 | } |
| 1166 | |
| 1167 | #define min_not_zero(l, r) (l == 0) ? r : ((r == 0) ? l : min(l, r)) |
| 1168 | |
| 1169 | /* |
| 1170 | * Set the target "split_io" field to the minimum of all the snapshots' |
| 1171 | * chunk sizes. |
| 1172 | */ |
| 1173 | static void origin_resume(struct dm_target *ti) |
| 1174 | { |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 1175 | struct dm_dev *dev = ti->private; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1176 | struct dm_snapshot *snap; |
| 1177 | struct origin *o; |
| 1178 | chunk_t chunk_size = 0; |
| 1179 | |
| 1180 | down_read(&_origins_lock); |
| 1181 | o = __lookup_origin(dev->bdev); |
| 1182 | if (o) |
| 1183 | list_for_each_entry (snap, &o->snapshots, list) |
| 1184 | chunk_size = min_not_zero(chunk_size, snap->chunk_size); |
| 1185 | up_read(&_origins_lock); |
| 1186 | |
| 1187 | ti->split_io = chunk_size; |
| 1188 | } |
| 1189 | |
| 1190 | static int origin_status(struct dm_target *ti, status_type_t type, char *result, |
| 1191 | unsigned int maxlen) |
| 1192 | { |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 1193 | struct dm_dev *dev = ti->private; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1194 | |
| 1195 | switch (type) { |
| 1196 | case STATUSTYPE_INFO: |
| 1197 | result[0] = '\0'; |
| 1198 | break; |
| 1199 | |
| 1200 | case STATUSTYPE_TABLE: |
| 1201 | snprintf(result, maxlen, "%s", dev->name); |
| 1202 | break; |
| 1203 | } |
| 1204 | |
| 1205 | return 0; |
| 1206 | } |
| 1207 | |
| 1208 | static struct target_type origin_target = { |
| 1209 | .name = "snapshot-origin", |
Mark McLoughlin | 4c7e3bf | 2006-10-03 01:15:25 -0700 | [diff] [blame] | 1210 | .version = {1, 5, 0}, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1211 | .module = THIS_MODULE, |
| 1212 | .ctr = origin_ctr, |
| 1213 | .dtr = origin_dtr, |
| 1214 | .map = origin_map, |
| 1215 | .resume = origin_resume, |
| 1216 | .status = origin_status, |
| 1217 | }; |
| 1218 | |
| 1219 | static struct target_type snapshot_target = { |
| 1220 | .name = "snapshot", |
Mark McLoughlin | 4c7e3bf | 2006-10-03 01:15:25 -0700 | [diff] [blame] | 1221 | .version = {1, 5, 0}, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1222 | .module = THIS_MODULE, |
| 1223 | .ctr = snapshot_ctr, |
| 1224 | .dtr = snapshot_dtr, |
| 1225 | .map = snapshot_map, |
| 1226 | .resume = snapshot_resume, |
| 1227 | .status = snapshot_status, |
| 1228 | }; |
| 1229 | |
| 1230 | static int __init dm_snapshot_init(void) |
| 1231 | { |
| 1232 | int r; |
| 1233 | |
| 1234 | r = dm_register_target(&snapshot_target); |
| 1235 | if (r) { |
| 1236 | DMERR("snapshot target register failed %d", r); |
| 1237 | return r; |
| 1238 | } |
| 1239 | |
| 1240 | r = dm_register_target(&origin_target); |
| 1241 | if (r < 0) { |
Alasdair G Kergon | 72d9486 | 2006-06-26 00:27:35 -0700 | [diff] [blame] | 1242 | DMERR("Origin target register failed %d", r); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1243 | goto bad1; |
| 1244 | } |
| 1245 | |
| 1246 | r = init_origin_hash(); |
| 1247 | if (r) { |
| 1248 | DMERR("init_origin_hash failed."); |
| 1249 | goto bad2; |
| 1250 | } |
| 1251 | |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 1252 | exception_cache = KMEM_CACHE(dm_snap_exception, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1253 | if (!exception_cache) { |
| 1254 | DMERR("Couldn't create exception cache."); |
| 1255 | r = -ENOMEM; |
| 1256 | goto bad3; |
| 1257 | } |
| 1258 | |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 1259 | pending_cache = KMEM_CACHE(dm_snap_pending_exception, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1260 | if (!pending_cache) { |
| 1261 | DMERR("Couldn't create pending cache."); |
| 1262 | r = -ENOMEM; |
| 1263 | goto bad4; |
| 1264 | } |
| 1265 | |
Matthew Dobson | 93d2341 | 2006-03-26 01:37:50 -0800 | [diff] [blame] | 1266 | pending_pool = mempool_create_slab_pool(128, pending_cache); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1267 | if (!pending_pool) { |
| 1268 | DMERR("Couldn't create pending pool."); |
| 1269 | r = -ENOMEM; |
| 1270 | goto bad5; |
| 1271 | } |
| 1272 | |
Alasdair G Kergon | ca3a931 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 1273 | ksnapd = create_singlethread_workqueue("ksnapd"); |
| 1274 | if (!ksnapd) { |
| 1275 | DMERR("Failed to create ksnapd workqueue."); |
| 1276 | r = -ENOMEM; |
| 1277 | goto bad6; |
| 1278 | } |
| 1279 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1280 | return 0; |
| 1281 | |
Alasdair G Kergon | ca3a931 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 1282 | bad6: |
| 1283 | mempool_destroy(pending_pool); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1284 | bad5: |
| 1285 | kmem_cache_destroy(pending_cache); |
| 1286 | bad4: |
| 1287 | kmem_cache_destroy(exception_cache); |
| 1288 | bad3: |
| 1289 | exit_origin_hash(); |
| 1290 | bad2: |
| 1291 | dm_unregister_target(&origin_target); |
| 1292 | bad1: |
| 1293 | dm_unregister_target(&snapshot_target); |
| 1294 | return r; |
| 1295 | } |
| 1296 | |
| 1297 | static void __exit dm_snapshot_exit(void) |
| 1298 | { |
| 1299 | int r; |
| 1300 | |
Alasdair G Kergon | ca3a931 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 1301 | destroy_workqueue(ksnapd); |
| 1302 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1303 | r = dm_unregister_target(&snapshot_target); |
| 1304 | if (r) |
| 1305 | DMERR("snapshot unregister failed %d", r); |
| 1306 | |
| 1307 | r = dm_unregister_target(&origin_target); |
| 1308 | if (r) |
| 1309 | DMERR("origin unregister failed %d", r); |
| 1310 | |
| 1311 | exit_origin_hash(); |
| 1312 | mempool_destroy(pending_pool); |
| 1313 | kmem_cache_destroy(pending_cache); |
| 1314 | kmem_cache_destroy(exception_cache); |
| 1315 | } |
| 1316 | |
| 1317 | /* Module hooks */ |
| 1318 | module_init(dm_snapshot_init); |
| 1319 | module_exit(dm_snapshot_exit); |
| 1320 | |
| 1321 | MODULE_DESCRIPTION(DM_NAME " snapshot target"); |
| 1322 | MODULE_AUTHOR("Joe Thornber"); |
| 1323 | MODULE_LICENSE("GPL"); |