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/device-mapper.h> |
Mikulas Patocka | 90fa152 | 2009-01-06 03:04:54 +0000 | [diff] [blame] | 11 | #include <linux/delay.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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> |
Alasdair G Kergon | a765e20 | 2008-04-24 22:02:01 +0100 | [diff] [blame] | 21 | #include <linux/dm-kcopyd.h> |
Jonathan Brassow | ccc45ea | 2009-04-02 19:55:34 +0100 | [diff] [blame] | 22 | #include <linux/workqueue.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 23 | |
Jonathan Brassow | aea53d9 | 2009-01-06 03:05:15 +0000 | [diff] [blame] | 24 | #include "dm-exception-store.h" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | /* |
Milan Broz | 8ee2767 | 2008-04-24 21:42:36 +0100 | [diff] [blame] | 39 | * Reserve 1MB for each snapshot initially (with minimum of 1 page). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 40 | */ |
Milan Broz | 8ee2767 | 2008-04-24 21:42:36 +0100 | [diff] [blame] | 41 | #define SNAPSHOT_PAGES (((1UL << 20) >> PAGE_SHIFT) ? : 1) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 42 | |
Mikulas Patocka | cd45daf | 2008-07-21 12:00:32 +0100 | [diff] [blame] | 43 | /* |
| 44 | * The size of the mempool used to track chunks in use. |
| 45 | */ |
| 46 | #define MIN_IOS 256 |
| 47 | |
Jonathan Brassow | ccc45ea | 2009-04-02 19:55:34 +0100 | [diff] [blame] | 48 | #define DM_TRACKED_CHUNK_HASH_SIZE 16 |
| 49 | #define DM_TRACKED_CHUNK_HASH(x) ((unsigned long)(x) & \ |
| 50 | (DM_TRACKED_CHUNK_HASH_SIZE - 1)) |
| 51 | |
Jon Brassow | 191437a | 2009-12-10 23:52:10 +0000 | [diff] [blame] | 52 | struct dm_exception_table { |
Jonathan Brassow | ccc45ea | 2009-04-02 19:55:34 +0100 | [diff] [blame] | 53 | uint32_t hash_mask; |
| 54 | unsigned hash_shift; |
| 55 | struct list_head *table; |
| 56 | }; |
| 57 | |
| 58 | struct dm_snapshot { |
| 59 | struct rw_semaphore lock; |
| 60 | |
| 61 | struct dm_dev *origin; |
Mike Snitzer | fc56f6f | 2009-12-10 23:52:12 +0000 | [diff] [blame] | 62 | struct dm_dev *cow; |
| 63 | |
| 64 | struct dm_target *ti; |
Jonathan Brassow | ccc45ea | 2009-04-02 19:55:34 +0100 | [diff] [blame] | 65 | |
| 66 | /* List of snapshots per Origin */ |
| 67 | struct list_head list; |
| 68 | |
| 69 | /* You can't use a snapshot if this is 0 (e.g. if full) */ |
| 70 | int valid; |
| 71 | |
| 72 | /* Origin writes don't trigger exceptions until this is set */ |
| 73 | int active; |
| 74 | |
Mike Snitzer | c26655c | 2009-12-10 23:52:12 +0000 | [diff] [blame] | 75 | /* Whether or not owning mapped_device is suspended */ |
| 76 | int suspended; |
| 77 | |
Jonathan Brassow | ccc45ea | 2009-04-02 19:55:34 +0100 | [diff] [blame] | 78 | mempool_t *pending_pool; |
| 79 | |
| 80 | atomic_t pending_exceptions_count; |
| 81 | |
Jon Brassow | 191437a | 2009-12-10 23:52:10 +0000 | [diff] [blame] | 82 | struct dm_exception_table pending; |
| 83 | struct dm_exception_table complete; |
Jonathan Brassow | ccc45ea | 2009-04-02 19:55:34 +0100 | [diff] [blame] | 84 | |
| 85 | /* |
| 86 | * pe_lock protects all pending_exception operations and access |
| 87 | * as well as the snapshot_bios list. |
| 88 | */ |
| 89 | spinlock_t pe_lock; |
| 90 | |
| 91 | /* The on disk metadata handler */ |
| 92 | struct dm_exception_store *store; |
| 93 | |
| 94 | struct dm_kcopyd_client *kcopyd_client; |
| 95 | |
| 96 | /* Queue of snapshot writes for ksnapd to flush */ |
| 97 | struct bio_list queued_bios; |
| 98 | struct work_struct queued_bios_work; |
| 99 | |
| 100 | /* Chunks with outstanding reads */ |
| 101 | mempool_t *tracked_chunk_pool; |
| 102 | spinlock_t tracked_chunk_lock; |
| 103 | struct hlist_head tracked_chunk_hash[DM_TRACKED_CHUNK_HASH_SIZE]; |
| 104 | }; |
| 105 | |
Mike Snitzer | fc56f6f | 2009-12-10 23:52:12 +0000 | [diff] [blame] | 106 | struct dm_dev *dm_snap_cow(struct dm_snapshot *s) |
| 107 | { |
| 108 | return s->cow; |
| 109 | } |
| 110 | EXPORT_SYMBOL(dm_snap_cow); |
| 111 | |
Adrian Bunk | c642f9e | 2006-12-08 02:41:13 -0800 | [diff] [blame] | 112 | static struct workqueue_struct *ksnapd; |
David Howells | c402895 | 2006-11-22 14:57:56 +0000 | [diff] [blame] | 113 | static void flush_queued_bios(struct work_struct *work); |
Alasdair G Kergon | ca3a931 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 114 | |
Jonathan Brassow | ccc45ea | 2009-04-02 19:55:34 +0100 | [diff] [blame] | 115 | static sector_t chunk_to_sector(struct dm_exception_store *store, |
| 116 | chunk_t chunk) |
| 117 | { |
| 118 | return chunk << store->chunk_shift; |
| 119 | } |
| 120 | |
| 121 | static int bdev_equal(struct block_device *lhs, struct block_device *rhs) |
| 122 | { |
| 123 | /* |
| 124 | * There is only ever one instance of a particular block |
| 125 | * device so we can compare pointers safely. |
| 126 | */ |
| 127 | return lhs == rhs; |
| 128 | } |
| 129 | |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 130 | struct dm_snap_pending_exception { |
Jon Brassow | 1d4989c | 2009-12-10 23:52:10 +0000 | [diff] [blame] | 131 | struct dm_exception e; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 132 | |
| 133 | /* |
| 134 | * Origin buffers waiting for this to complete are held |
| 135 | * in a bio list |
| 136 | */ |
| 137 | struct bio_list origin_bios; |
| 138 | struct bio_list snapshot_bios; |
| 139 | |
| 140 | /* |
Alasdair G Kergon | eccf081 | 2006-03-27 01:17:42 -0800 | [diff] [blame] | 141 | * Short-term queue of pending exceptions prior to submission. |
| 142 | */ |
| 143 | struct list_head list; |
| 144 | |
| 145 | /* |
Alasdair G Kergon | b4b610f | 2006-03-27 01:17:44 -0800 | [diff] [blame] | 146 | * The primary pending_exception is the one that holds |
Alasdair G Kergon | 4b832e8 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 147 | * the ref_count and the list of origin_bios for a |
Alasdair G Kergon | b4b610f | 2006-03-27 01:17:44 -0800 | [diff] [blame] | 148 | * group of pending_exceptions. It is always last to get freed. |
| 149 | * These fields get set up when writing to the origin. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 150 | */ |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 151 | struct dm_snap_pending_exception *primary_pe; |
Alasdair G Kergon | b4b610f | 2006-03-27 01:17:44 -0800 | [diff] [blame] | 152 | |
| 153 | /* |
| 154 | * Number of pending_exceptions processing this chunk. |
| 155 | * When this drops to zero we must complete the origin bios. |
| 156 | * If incrementing or decrementing this, hold pe->snap->lock for |
| 157 | * the sibling concerned and not pe->primary_pe->snap->lock unless |
| 158 | * they are the same. |
| 159 | */ |
Alasdair G Kergon | 4b832e8 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 160 | atomic_t ref_count; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 161 | |
| 162 | /* Pointer back to snapshot context */ |
| 163 | struct dm_snapshot *snap; |
| 164 | |
| 165 | /* |
| 166 | * 1 indicates the exception has already been sent to |
| 167 | * kcopyd. |
| 168 | */ |
| 169 | int started; |
| 170 | }; |
| 171 | |
| 172 | /* |
| 173 | * Hash table mapping origin volumes to lists of snapshots and |
| 174 | * a lock to protect it |
| 175 | */ |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 176 | static struct kmem_cache *exception_cache; |
| 177 | static struct kmem_cache *pending_cache; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 178 | |
Mikulas Patocka | cd45daf | 2008-07-21 12:00:32 +0100 | [diff] [blame] | 179 | struct dm_snap_tracked_chunk { |
| 180 | struct hlist_node node; |
| 181 | chunk_t chunk; |
| 182 | }; |
| 183 | |
| 184 | static struct kmem_cache *tracked_chunk_cache; |
| 185 | |
| 186 | static struct dm_snap_tracked_chunk *track_chunk(struct dm_snapshot *s, |
| 187 | chunk_t chunk) |
| 188 | { |
| 189 | struct dm_snap_tracked_chunk *c = mempool_alloc(s->tracked_chunk_pool, |
| 190 | GFP_NOIO); |
| 191 | unsigned long flags; |
| 192 | |
| 193 | c->chunk = chunk; |
| 194 | |
| 195 | spin_lock_irqsave(&s->tracked_chunk_lock, flags); |
| 196 | hlist_add_head(&c->node, |
| 197 | &s->tracked_chunk_hash[DM_TRACKED_CHUNK_HASH(chunk)]); |
| 198 | spin_unlock_irqrestore(&s->tracked_chunk_lock, flags); |
| 199 | |
| 200 | return c; |
| 201 | } |
| 202 | |
| 203 | static void stop_tracking_chunk(struct dm_snapshot *s, |
| 204 | struct dm_snap_tracked_chunk *c) |
| 205 | { |
| 206 | unsigned long flags; |
| 207 | |
| 208 | spin_lock_irqsave(&s->tracked_chunk_lock, flags); |
| 209 | hlist_del(&c->node); |
| 210 | spin_unlock_irqrestore(&s->tracked_chunk_lock, flags); |
| 211 | |
| 212 | mempool_free(c, s->tracked_chunk_pool); |
| 213 | } |
| 214 | |
Mikulas Patocka | a8d41b5 | 2008-07-21 12:00:34 +0100 | [diff] [blame] | 215 | static int __chunk_is_tracked(struct dm_snapshot *s, chunk_t chunk) |
| 216 | { |
| 217 | struct dm_snap_tracked_chunk *c; |
| 218 | struct hlist_node *hn; |
| 219 | int found = 0; |
| 220 | |
| 221 | spin_lock_irq(&s->tracked_chunk_lock); |
| 222 | |
| 223 | hlist_for_each_entry(c, hn, |
| 224 | &s->tracked_chunk_hash[DM_TRACKED_CHUNK_HASH(chunk)], node) { |
| 225 | if (c->chunk == chunk) { |
| 226 | found = 1; |
| 227 | break; |
| 228 | } |
| 229 | } |
| 230 | |
| 231 | spin_unlock_irq(&s->tracked_chunk_lock); |
| 232 | |
| 233 | return found; |
| 234 | } |
| 235 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 236 | /* |
| 237 | * One of these per registered origin, held in the snapshot_origins hash |
| 238 | */ |
| 239 | struct origin { |
| 240 | /* The origin device */ |
| 241 | struct block_device *bdev; |
| 242 | |
| 243 | struct list_head hash_list; |
| 244 | |
| 245 | /* List of snapshots for this origin */ |
| 246 | struct list_head snapshots; |
| 247 | }; |
| 248 | |
| 249 | /* |
| 250 | * Size of the hash table for origin volumes. If we make this |
| 251 | * the size of the minors list then it should be nearly perfect |
| 252 | */ |
| 253 | #define ORIGIN_HASH_SIZE 256 |
| 254 | #define ORIGIN_MASK 0xFF |
| 255 | static struct list_head *_origins; |
| 256 | static struct rw_semaphore _origins_lock; |
| 257 | |
| 258 | static int init_origin_hash(void) |
| 259 | { |
| 260 | int i; |
| 261 | |
| 262 | _origins = kmalloc(ORIGIN_HASH_SIZE * sizeof(struct list_head), |
| 263 | GFP_KERNEL); |
| 264 | if (!_origins) { |
Alasdair G Kergon | 72d9486 | 2006-06-26 00:27:35 -0700 | [diff] [blame] | 265 | DMERR("unable to allocate memory"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 266 | return -ENOMEM; |
| 267 | } |
| 268 | |
| 269 | for (i = 0; i < ORIGIN_HASH_SIZE; i++) |
| 270 | INIT_LIST_HEAD(_origins + i); |
| 271 | init_rwsem(&_origins_lock); |
| 272 | |
| 273 | return 0; |
| 274 | } |
| 275 | |
| 276 | static void exit_origin_hash(void) |
| 277 | { |
| 278 | kfree(_origins); |
| 279 | } |
| 280 | |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 281 | static unsigned origin_hash(struct block_device *bdev) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 282 | { |
| 283 | return bdev->bd_dev & ORIGIN_MASK; |
| 284 | } |
| 285 | |
| 286 | static struct origin *__lookup_origin(struct block_device *origin) |
| 287 | { |
| 288 | struct list_head *ol; |
| 289 | struct origin *o; |
| 290 | |
| 291 | ol = &_origins[origin_hash(origin)]; |
| 292 | list_for_each_entry (o, ol, hash_list) |
| 293 | if (bdev_equal(o->bdev, origin)) |
| 294 | return o; |
| 295 | |
| 296 | return NULL; |
| 297 | } |
| 298 | |
| 299 | static void __insert_origin(struct origin *o) |
| 300 | { |
| 301 | struct list_head *sl = &_origins[origin_hash(o->bdev)]; |
| 302 | list_add_tail(&o->hash_list, sl); |
| 303 | } |
| 304 | |
| 305 | /* |
| 306 | * Make a note of the snapshot and its origin so we can look it |
| 307 | * up when the origin has a write on it. |
| 308 | */ |
| 309 | static int register_snapshot(struct dm_snapshot *snap) |
| 310 | { |
Mikulas Patocka | 6d45d93 | 2009-10-16 23:18:14 +0100 | [diff] [blame] | 311 | struct dm_snapshot *l; |
Mikulas Patocka | 60c856c8 | 2008-10-30 13:33:12 +0000 | [diff] [blame] | 312 | struct origin *o, *new_o; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 313 | struct block_device *bdev = snap->origin->bdev; |
| 314 | |
Mikulas Patocka | 60c856c8 | 2008-10-30 13:33:12 +0000 | [diff] [blame] | 315 | new_o = kmalloc(sizeof(*new_o), GFP_KERNEL); |
| 316 | if (!new_o) |
| 317 | return -ENOMEM; |
| 318 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 319 | down_write(&_origins_lock); |
| 320 | o = __lookup_origin(bdev); |
| 321 | |
Mikulas Patocka | 60c856c8 | 2008-10-30 13:33:12 +0000 | [diff] [blame] | 322 | if (o) |
| 323 | kfree(new_o); |
| 324 | else { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 325 | /* New origin */ |
Mikulas Patocka | 60c856c8 | 2008-10-30 13:33:12 +0000 | [diff] [blame] | 326 | o = new_o; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 327 | |
| 328 | /* Initialise the struct */ |
| 329 | INIT_LIST_HEAD(&o->snapshots); |
| 330 | o->bdev = bdev; |
| 331 | |
| 332 | __insert_origin(o); |
| 333 | } |
| 334 | |
Mikulas Patocka | 6d45d93 | 2009-10-16 23:18:14 +0100 | [diff] [blame] | 335 | /* Sort the list according to chunk size, largest-first smallest-last */ |
| 336 | list_for_each_entry(l, &o->snapshots, list) |
| 337 | if (l->store->chunk_size < snap->store->chunk_size) |
| 338 | break; |
| 339 | list_add_tail(&snap->list, &l->list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 340 | |
| 341 | up_write(&_origins_lock); |
| 342 | return 0; |
| 343 | } |
| 344 | |
| 345 | static void unregister_snapshot(struct dm_snapshot *s) |
| 346 | { |
| 347 | struct origin *o; |
| 348 | |
| 349 | down_write(&_origins_lock); |
| 350 | o = __lookup_origin(s->origin->bdev); |
| 351 | |
| 352 | list_del(&s->list); |
| 353 | if (list_empty(&o->snapshots)) { |
| 354 | list_del(&o->hash_list); |
| 355 | kfree(o); |
| 356 | } |
| 357 | |
| 358 | up_write(&_origins_lock); |
| 359 | } |
| 360 | |
| 361 | /* |
| 362 | * Implementation of the exception hash tables. |
Milan Broz | d74f81f | 2008-02-08 02:11:27 +0000 | [diff] [blame] | 363 | * The lowest hash_shift bits of the chunk number are ignored, allowing |
| 364 | * some consecutive chunks to be grouped together. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 365 | */ |
Jon Brassow | 3510cb9 | 2009-12-10 23:52:11 +0000 | [diff] [blame] | 366 | static int dm_exception_table_init(struct dm_exception_table *et, |
| 367 | uint32_t size, unsigned hash_shift) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 368 | { |
| 369 | unsigned int i; |
| 370 | |
Milan Broz | d74f81f | 2008-02-08 02:11:27 +0000 | [diff] [blame] | 371 | et->hash_shift = hash_shift; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 372 | et->hash_mask = size - 1; |
| 373 | et->table = dm_vcalloc(size, sizeof(struct list_head)); |
| 374 | if (!et->table) |
| 375 | return -ENOMEM; |
| 376 | |
| 377 | for (i = 0; i < size; i++) |
| 378 | INIT_LIST_HEAD(et->table + i); |
| 379 | |
| 380 | return 0; |
| 381 | } |
| 382 | |
Jon Brassow | 3510cb9 | 2009-12-10 23:52:11 +0000 | [diff] [blame] | 383 | static void dm_exception_table_exit(struct dm_exception_table *et, |
| 384 | struct kmem_cache *mem) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 385 | { |
| 386 | struct list_head *slot; |
Jon Brassow | 1d4989c | 2009-12-10 23:52:10 +0000 | [diff] [blame] | 387 | struct dm_exception *ex, *next; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 388 | int i, size; |
| 389 | |
| 390 | size = et->hash_mask + 1; |
| 391 | for (i = 0; i < size; i++) { |
| 392 | slot = et->table + i; |
| 393 | |
| 394 | list_for_each_entry_safe (ex, next, slot, hash_list) |
| 395 | kmem_cache_free(mem, ex); |
| 396 | } |
| 397 | |
| 398 | vfree(et->table); |
| 399 | } |
| 400 | |
Jon Brassow | 191437a | 2009-12-10 23:52:10 +0000 | [diff] [blame] | 401 | static uint32_t exception_hash(struct dm_exception_table *et, chunk_t chunk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 402 | { |
Milan Broz | d74f81f | 2008-02-08 02:11:27 +0000 | [diff] [blame] | 403 | return (chunk >> et->hash_shift) & et->hash_mask; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 404 | } |
| 405 | |
Jon Brassow | 3510cb9 | 2009-12-10 23:52:11 +0000 | [diff] [blame] | 406 | static void dm_remove_exception(struct dm_exception *e) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 407 | { |
| 408 | list_del(&e->hash_list); |
| 409 | } |
| 410 | |
| 411 | /* |
| 412 | * Return the exception data for a sector, or NULL if not |
| 413 | * remapped. |
| 414 | */ |
Jon Brassow | 3510cb9 | 2009-12-10 23:52:11 +0000 | [diff] [blame] | 415 | static struct dm_exception *dm_lookup_exception(struct dm_exception_table *et, |
| 416 | chunk_t chunk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 417 | { |
| 418 | struct list_head *slot; |
Jon Brassow | 1d4989c | 2009-12-10 23:52:10 +0000 | [diff] [blame] | 419 | struct dm_exception *e; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 420 | |
| 421 | slot = &et->table[exception_hash(et, chunk)]; |
| 422 | list_for_each_entry (e, slot, hash_list) |
Milan Broz | d74f81f | 2008-02-08 02:11:27 +0000 | [diff] [blame] | 423 | if (chunk >= e->old_chunk && |
| 424 | chunk <= e->old_chunk + dm_consecutive_chunk_count(e)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 425 | return e; |
| 426 | |
| 427 | return NULL; |
| 428 | } |
| 429 | |
Jon Brassow | 3510cb9 | 2009-12-10 23:52:11 +0000 | [diff] [blame] | 430 | static struct dm_exception *alloc_completed_exception(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 431 | { |
Jon Brassow | 1d4989c | 2009-12-10 23:52:10 +0000 | [diff] [blame] | 432 | struct dm_exception *e; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 433 | |
| 434 | e = kmem_cache_alloc(exception_cache, GFP_NOIO); |
| 435 | if (!e) |
| 436 | e = kmem_cache_alloc(exception_cache, GFP_ATOMIC); |
| 437 | |
| 438 | return e; |
| 439 | } |
| 440 | |
Jon Brassow | 3510cb9 | 2009-12-10 23:52:11 +0000 | [diff] [blame] | 441 | static void free_completed_exception(struct dm_exception *e) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 442 | { |
| 443 | kmem_cache_free(exception_cache, e); |
| 444 | } |
| 445 | |
Mikulas Patocka | 92e8681 | 2008-07-21 12:00:35 +0100 | [diff] [blame] | 446 | static struct dm_snap_pending_exception *alloc_pending_exception(struct dm_snapshot *s) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 447 | { |
Mikulas Patocka | 92e8681 | 2008-07-21 12:00:35 +0100 | [diff] [blame] | 448 | struct dm_snap_pending_exception *pe = mempool_alloc(s->pending_pool, |
| 449 | GFP_NOIO); |
| 450 | |
Mikulas Patocka | 879129d2 | 2008-10-30 13:33:16 +0000 | [diff] [blame] | 451 | atomic_inc(&s->pending_exceptions_count); |
Mikulas Patocka | 92e8681 | 2008-07-21 12:00:35 +0100 | [diff] [blame] | 452 | pe->snap = s; |
| 453 | |
| 454 | return pe; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 455 | } |
| 456 | |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 457 | static void free_pending_exception(struct dm_snap_pending_exception *pe) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 458 | { |
Mikulas Patocka | 879129d2 | 2008-10-30 13:33:16 +0000 | [diff] [blame] | 459 | struct dm_snapshot *s = pe->snap; |
| 460 | |
| 461 | mempool_free(pe, s->pending_pool); |
| 462 | smp_mb__before_atomic_dec(); |
| 463 | atomic_dec(&s->pending_exceptions_count); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 464 | } |
| 465 | |
Jon Brassow | 3510cb9 | 2009-12-10 23:52:11 +0000 | [diff] [blame] | 466 | static void dm_insert_exception(struct dm_exception_table *eh, |
| 467 | struct dm_exception *new_e) |
Milan Broz | d74f81f | 2008-02-08 02:11:27 +0000 | [diff] [blame] | 468 | { |
Milan Broz | d74f81f | 2008-02-08 02:11:27 +0000 | [diff] [blame] | 469 | struct list_head *l; |
Jon Brassow | 1d4989c | 2009-12-10 23:52:10 +0000 | [diff] [blame] | 470 | struct dm_exception *e = NULL; |
Milan Broz | d74f81f | 2008-02-08 02:11:27 +0000 | [diff] [blame] | 471 | |
| 472 | l = &eh->table[exception_hash(eh, new_e->old_chunk)]; |
| 473 | |
| 474 | /* Add immediately if this table doesn't support consecutive chunks */ |
| 475 | if (!eh->hash_shift) |
| 476 | goto out; |
| 477 | |
| 478 | /* List is ordered by old_chunk */ |
| 479 | list_for_each_entry_reverse(e, l, hash_list) { |
| 480 | /* Insert after an existing chunk? */ |
| 481 | if (new_e->old_chunk == (e->old_chunk + |
| 482 | dm_consecutive_chunk_count(e) + 1) && |
| 483 | new_e->new_chunk == (dm_chunk_number(e->new_chunk) + |
| 484 | dm_consecutive_chunk_count(e) + 1)) { |
| 485 | dm_consecutive_chunk_count_inc(e); |
Jon Brassow | 3510cb9 | 2009-12-10 23:52:11 +0000 | [diff] [blame] | 486 | free_completed_exception(new_e); |
Milan Broz | d74f81f | 2008-02-08 02:11:27 +0000 | [diff] [blame] | 487 | return; |
| 488 | } |
| 489 | |
| 490 | /* Insert before an existing chunk? */ |
| 491 | if (new_e->old_chunk == (e->old_chunk - 1) && |
| 492 | new_e->new_chunk == (dm_chunk_number(e->new_chunk) - 1)) { |
| 493 | dm_consecutive_chunk_count_inc(e); |
| 494 | e->old_chunk--; |
| 495 | e->new_chunk--; |
Jon Brassow | 3510cb9 | 2009-12-10 23:52:11 +0000 | [diff] [blame] | 496 | free_completed_exception(new_e); |
Milan Broz | d74f81f | 2008-02-08 02:11:27 +0000 | [diff] [blame] | 497 | return; |
| 498 | } |
| 499 | |
| 500 | if (new_e->old_chunk > e->old_chunk) |
| 501 | break; |
| 502 | } |
| 503 | |
| 504 | out: |
| 505 | list_add(&new_e->hash_list, e ? &e->hash_list : l); |
| 506 | } |
| 507 | |
Jonathan Brassow | a159c1a | 2009-01-06 03:05:19 +0000 | [diff] [blame] | 508 | /* |
| 509 | * Callback used by the exception stores to load exceptions when |
| 510 | * initialising. |
| 511 | */ |
| 512 | static int dm_add_exception(void *context, chunk_t old, chunk_t new) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 513 | { |
Jonathan Brassow | a159c1a | 2009-01-06 03:05:19 +0000 | [diff] [blame] | 514 | struct dm_snapshot *s = context; |
Jon Brassow | 1d4989c | 2009-12-10 23:52:10 +0000 | [diff] [blame] | 515 | struct dm_exception *e; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 516 | |
Jon Brassow | 3510cb9 | 2009-12-10 23:52:11 +0000 | [diff] [blame] | 517 | e = alloc_completed_exception(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 518 | if (!e) |
| 519 | return -ENOMEM; |
| 520 | |
| 521 | e->old_chunk = old; |
Milan Broz | d74f81f | 2008-02-08 02:11:27 +0000 | [diff] [blame] | 522 | |
| 523 | /* Consecutive_count is implicitly initialised to zero */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 524 | e->new_chunk = new; |
Milan Broz | d74f81f | 2008-02-08 02:11:27 +0000 | [diff] [blame] | 525 | |
Jon Brassow | 3510cb9 | 2009-12-10 23:52:11 +0000 | [diff] [blame] | 526 | dm_insert_exception(&s->complete, e); |
Milan Broz | d74f81f | 2008-02-08 02:11:27 +0000 | [diff] [blame] | 527 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 528 | return 0; |
| 529 | } |
| 530 | |
Mikulas Patocka | 7e201b3 | 2009-12-10 23:52:08 +0000 | [diff] [blame] | 531 | #define min_not_zero(l, r) (((l) == 0) ? (r) : (((r) == 0) ? (l) : min(l, r))) |
| 532 | |
| 533 | /* |
| 534 | * Return a minimum chunk size of all snapshots that have the specified origin. |
| 535 | * Return zero if the origin has no snapshots. |
| 536 | */ |
| 537 | static sector_t __minimum_chunk_size(struct origin *o) |
| 538 | { |
| 539 | struct dm_snapshot *snap; |
| 540 | unsigned chunk_size = 0; |
| 541 | |
| 542 | if (o) |
| 543 | list_for_each_entry(snap, &o->snapshots, list) |
| 544 | chunk_size = min_not_zero(chunk_size, |
| 545 | snap->store->chunk_size); |
| 546 | |
| 547 | return chunk_size; |
| 548 | } |
| 549 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 550 | /* |
| 551 | * Hard coded magic. |
| 552 | */ |
| 553 | static int calc_max_buckets(void) |
| 554 | { |
| 555 | /* use a fixed size of 2MB */ |
| 556 | unsigned long mem = 2 * 1024 * 1024; |
| 557 | mem /= sizeof(struct list_head); |
| 558 | |
| 559 | return mem; |
| 560 | } |
| 561 | |
| 562 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 563 | * Allocate room for a suitable hash table. |
| 564 | */ |
Jonathan Brassow | fee1998 | 2009-04-02 19:55:34 +0100 | [diff] [blame] | 565 | static int init_hash_tables(struct dm_snapshot *s) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 566 | { |
| 567 | sector_t hash_size, cow_dev_size, origin_dev_size, max_buckets; |
| 568 | |
| 569 | /* |
| 570 | * Calculate based on the size of the original volume or |
| 571 | * the COW volume... |
| 572 | */ |
Mike Snitzer | fc56f6f | 2009-12-10 23:52:12 +0000 | [diff] [blame] | 573 | cow_dev_size = get_dev_size(s->cow->bdev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 574 | origin_dev_size = get_dev_size(s->origin->bdev); |
| 575 | max_buckets = calc_max_buckets(); |
| 576 | |
Jonathan Brassow | fee1998 | 2009-04-02 19:55:34 +0100 | [diff] [blame] | 577 | hash_size = min(origin_dev_size, cow_dev_size) >> s->store->chunk_shift; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 578 | hash_size = min(hash_size, max_buckets); |
| 579 | |
Mikulas Patocka | 8e87b9b | 2009-12-10 23:51:54 +0000 | [diff] [blame] | 580 | if (hash_size < 64) |
| 581 | hash_size = 64; |
Robert P. J. Day | 8defd83 | 2008-02-08 02:10:06 +0000 | [diff] [blame] | 582 | hash_size = rounddown_pow_of_two(hash_size); |
Jon Brassow | 3510cb9 | 2009-12-10 23:52:11 +0000 | [diff] [blame] | 583 | if (dm_exception_table_init(&s->complete, hash_size, |
| 584 | DM_CHUNK_CONSECUTIVE_BITS)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 585 | return -ENOMEM; |
| 586 | |
| 587 | /* |
| 588 | * Allocate hash table for in-flight exceptions |
| 589 | * Make this smaller than the real hash table |
| 590 | */ |
| 591 | hash_size >>= 3; |
| 592 | if (hash_size < 64) |
| 593 | hash_size = 64; |
| 594 | |
Jon Brassow | 3510cb9 | 2009-12-10 23:52:11 +0000 | [diff] [blame] | 595 | if (dm_exception_table_init(&s->pending, hash_size, 0)) { |
| 596 | dm_exception_table_exit(&s->complete, exception_cache); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 597 | return -ENOMEM; |
| 598 | } |
| 599 | |
| 600 | return 0; |
| 601 | } |
| 602 | |
| 603 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 604 | * Construct a snapshot mapping: <origin_dev> <COW-dev> <p/n> <chunk-size> |
| 605 | */ |
| 606 | static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) |
| 607 | { |
| 608 | struct dm_snapshot *s; |
Mikulas Patocka | cd45daf | 2008-07-21 12:00:32 +0100 | [diff] [blame] | 609 | int i; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 610 | int r = -EINVAL; |
Mike Snitzer | fc56f6f | 2009-12-10 23:52:12 +0000 | [diff] [blame] | 611 | char *origin_path, *cow_path; |
Jonathan Brassow | fee1998 | 2009-04-02 19:55:34 +0100 | [diff] [blame] | 612 | unsigned args_used; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 613 | |
Mark McLoughlin | 4c7e3bf | 2006-10-03 01:15:25 -0700 | [diff] [blame] | 614 | if (argc != 4) { |
Alasdair G Kergon | 72d9486 | 2006-06-26 00:27:35 -0700 | [diff] [blame] | 615 | ti->error = "requires exactly 4 arguments"; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 616 | r = -EINVAL; |
Mike Snitzer | fc56f6f | 2009-12-10 23:52:12 +0000 | [diff] [blame] | 617 | goto bad; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 618 | } |
| 619 | |
| 620 | origin_path = argv[0]; |
Jonathan Brassow | fee1998 | 2009-04-02 19:55:34 +0100 | [diff] [blame] | 621 | argv++; |
| 622 | argc--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 623 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 624 | s = kmalloc(sizeof(*s), GFP_KERNEL); |
Jonathan Brassow | fee1998 | 2009-04-02 19:55:34 +0100 | [diff] [blame] | 625 | if (!s) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 626 | ti->error = "Cannot allocate snapshot context private " |
| 627 | "structure"; |
| 628 | r = -ENOMEM; |
Mike Snitzer | fc56f6f | 2009-12-10 23:52:12 +0000 | [diff] [blame] | 629 | goto bad; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 630 | } |
| 631 | |
Mike Snitzer | fc56f6f | 2009-12-10 23:52:12 +0000 | [diff] [blame] | 632 | cow_path = argv[0]; |
| 633 | argv++; |
| 634 | argc--; |
| 635 | |
| 636 | r = dm_get_device(ti, cow_path, 0, 0, |
| 637 | FMODE_READ | FMODE_WRITE, &s->cow); |
| 638 | if (r) { |
| 639 | ti->error = "Cannot get COW device"; |
| 640 | goto bad_cow; |
| 641 | } |
| 642 | |
| 643 | r = dm_exception_store_create(ti, argc, argv, s, &args_used, &s->store); |
| 644 | if (r) { |
| 645 | ti->error = "Couldn't create exception store"; |
| 646 | r = -EINVAL; |
| 647 | goto bad_store; |
| 648 | } |
| 649 | |
| 650 | argv += args_used; |
| 651 | argc -= args_used; |
| 652 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 653 | r = dm_get_device(ti, origin_path, 0, ti->len, FMODE_READ, &s->origin); |
| 654 | if (r) { |
| 655 | ti->error = "Cannot get origin device"; |
Jonathan Brassow | fee1998 | 2009-04-02 19:55:34 +0100 | [diff] [blame] | 656 | goto bad_origin; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 657 | } |
| 658 | |
Mike Snitzer | fc56f6f | 2009-12-10 23:52:12 +0000 | [diff] [blame] | 659 | s->ti = ti; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 660 | s->valid = 1; |
Alasdair G Kergon | aa14ede | 2006-02-01 03:04:50 -0800 | [diff] [blame] | 661 | s->active = 0; |
Mike Snitzer | c26655c | 2009-12-10 23:52:12 +0000 | [diff] [blame] | 662 | s->suspended = 0; |
Mikulas Patocka | 879129d2 | 2008-10-30 13:33:16 +0000 | [diff] [blame] | 663 | atomic_set(&s->pending_exceptions_count, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 664 | init_rwsem(&s->lock); |
Alasdair G Kergon | ca3a931 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 665 | spin_lock_init(&s->pe_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 666 | |
| 667 | /* Allocate hash table for COW data */ |
Jonathan Brassow | fee1998 | 2009-04-02 19:55:34 +0100 | [diff] [blame] | 668 | if (init_hash_tables(s)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 669 | ti->error = "Unable to allocate hash table space"; |
| 670 | r = -ENOMEM; |
Jonathan Brassow | fee1998 | 2009-04-02 19:55:34 +0100 | [diff] [blame] | 671 | goto bad_hash_tables; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 672 | } |
| 673 | |
Heinz Mauelshagen | eb69aca | 2008-04-24 21:43:19 +0100 | [diff] [blame] | 674 | r = dm_kcopyd_client_create(SNAPSHOT_PAGES, &s->kcopyd_client); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 675 | if (r) { |
| 676 | ti->error = "Could not create kcopyd client"; |
Jonathan Brassow | fee1998 | 2009-04-02 19:55:34 +0100 | [diff] [blame] | 677 | goto bad_kcopyd; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 678 | } |
| 679 | |
Mikulas Patocka | 92e8681 | 2008-07-21 12:00:35 +0100 | [diff] [blame] | 680 | s->pending_pool = mempool_create_slab_pool(MIN_IOS, pending_cache); |
| 681 | if (!s->pending_pool) { |
| 682 | ti->error = "Could not allocate mempool for pending exceptions"; |
Jonathan Brassow | fee1998 | 2009-04-02 19:55:34 +0100 | [diff] [blame] | 683 | goto bad_pending_pool; |
Mikulas Patocka | 92e8681 | 2008-07-21 12:00:35 +0100 | [diff] [blame] | 684 | } |
| 685 | |
Mikulas Patocka | cd45daf | 2008-07-21 12:00:32 +0100 | [diff] [blame] | 686 | s->tracked_chunk_pool = mempool_create_slab_pool(MIN_IOS, |
| 687 | tracked_chunk_cache); |
| 688 | if (!s->tracked_chunk_pool) { |
| 689 | ti->error = "Could not allocate tracked_chunk mempool for " |
| 690 | "tracking reads"; |
Mikulas Patocka | 92e8681 | 2008-07-21 12:00:35 +0100 | [diff] [blame] | 691 | goto bad_tracked_chunk_pool; |
Mikulas Patocka | cd45daf | 2008-07-21 12:00:32 +0100 | [diff] [blame] | 692 | } |
| 693 | |
| 694 | for (i = 0; i < DM_TRACKED_CHUNK_HASH_SIZE; i++) |
| 695 | INIT_HLIST_HEAD(&s->tracked_chunk_hash[i]); |
| 696 | |
| 697 | spin_lock_init(&s->tracked_chunk_lock); |
| 698 | |
Alasdair G Kergon | aa14ede | 2006-02-01 03:04:50 -0800 | [diff] [blame] | 699 | /* Metadata must only be loaded into one table at once */ |
Jonathan Brassow | 493df71 | 2009-04-02 19:55:31 +0100 | [diff] [blame] | 700 | r = s->store->type->read_metadata(s->store, dm_add_exception, |
| 701 | (void *)s); |
Milan Broz | 0764147 | 2007-07-12 17:28:13 +0100 | [diff] [blame] | 702 | if (r < 0) { |
Mark McLoughlin | f9cea4f | 2006-10-03 01:15:25 -0700 | [diff] [blame] | 703 | ti->error = "Failed to read snapshot metadata"; |
Mikulas Patocka | cd45daf | 2008-07-21 12:00:32 +0100 | [diff] [blame] | 704 | goto bad_load_and_register; |
Milan Broz | 0764147 | 2007-07-12 17:28:13 +0100 | [diff] [blame] | 705 | } else if (r > 0) { |
| 706 | s->valid = 0; |
| 707 | DMWARN("Snapshot is marked invalid."); |
Mark McLoughlin | f9cea4f | 2006-10-03 01:15:25 -0700 | [diff] [blame] | 708 | } |
Alasdair G Kergon | aa14ede | 2006-02-01 03:04:50 -0800 | [diff] [blame] | 709 | |
Alasdair G Kergon | ca3a931 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 710 | bio_list_init(&s->queued_bios); |
David Howells | c402895 | 2006-11-22 14:57:56 +0000 | [diff] [blame] | 711 | INIT_WORK(&s->queued_bios_work, flush_queued_bios); |
Alasdair G Kergon | ca3a931 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 712 | |
Mikulas Patocka | 3f2412d | 2009-10-16 23:18:16 +0100 | [diff] [blame] | 713 | if (!s->store->chunk_size) { |
| 714 | ti->error = "Chunk size not set"; |
| 715 | goto bad_load_and_register; |
| 716 | } |
| 717 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 718 | /* Add snapshot to the list of snapshots for this origin */ |
Alasdair G Kergon | aa14ede | 2006-02-01 03:04:50 -0800 | [diff] [blame] | 719 | /* Exceptions aren't triggered till snapshot_resume() is called */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 720 | if (register_snapshot(s)) { |
| 721 | r = -EINVAL; |
| 722 | ti->error = "Cannot register snapshot origin"; |
Mikulas Patocka | cd45daf | 2008-07-21 12:00:32 +0100 | [diff] [blame] | 723 | goto bad_load_and_register; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 724 | } |
| 725 | |
| 726 | ti->private = s; |
Jonathan Brassow | d021684 | 2009-04-02 19:55:32 +0100 | [diff] [blame] | 727 | ti->split_io = s->store->chunk_size; |
Mikulas Patocka | 494b3ee | 2009-06-22 10:12:25 +0100 | [diff] [blame] | 728 | ti->num_flush_requests = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 729 | |
| 730 | return 0; |
| 731 | |
Jonathan Brassow | fee1998 | 2009-04-02 19:55:34 +0100 | [diff] [blame] | 732 | bad_load_and_register: |
Mikulas Patocka | cd45daf | 2008-07-21 12:00:32 +0100 | [diff] [blame] | 733 | mempool_destroy(s->tracked_chunk_pool); |
| 734 | |
Jonathan Brassow | fee1998 | 2009-04-02 19:55:34 +0100 | [diff] [blame] | 735 | bad_tracked_chunk_pool: |
Mikulas Patocka | 92e8681 | 2008-07-21 12:00:35 +0100 | [diff] [blame] | 736 | mempool_destroy(s->pending_pool); |
| 737 | |
Jonathan Brassow | fee1998 | 2009-04-02 19:55:34 +0100 | [diff] [blame] | 738 | bad_pending_pool: |
Heinz Mauelshagen | eb69aca | 2008-04-24 21:43:19 +0100 | [diff] [blame] | 739 | dm_kcopyd_client_destroy(s->kcopyd_client); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 740 | |
Jonathan Brassow | fee1998 | 2009-04-02 19:55:34 +0100 | [diff] [blame] | 741 | bad_kcopyd: |
Jon Brassow | 3510cb9 | 2009-12-10 23:52:11 +0000 | [diff] [blame] | 742 | dm_exception_table_exit(&s->pending, pending_cache); |
| 743 | dm_exception_table_exit(&s->complete, exception_cache); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 744 | |
Jonathan Brassow | fee1998 | 2009-04-02 19:55:34 +0100 | [diff] [blame] | 745 | bad_hash_tables: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 746 | dm_put_device(ti, s->origin); |
| 747 | |
Jonathan Brassow | fee1998 | 2009-04-02 19:55:34 +0100 | [diff] [blame] | 748 | bad_origin: |
Mike Snitzer | fc56f6f | 2009-12-10 23:52:12 +0000 | [diff] [blame] | 749 | dm_exception_store_destroy(s->store); |
| 750 | |
| 751 | bad_store: |
| 752 | dm_put_device(ti, s->cow); |
| 753 | |
| 754 | bad_cow: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 755 | kfree(s); |
| 756 | |
Mike Snitzer | fc56f6f | 2009-12-10 23:52:12 +0000 | [diff] [blame] | 757 | bad: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 758 | return r; |
| 759 | } |
| 760 | |
Milan Broz | 31c93a0 | 2006-12-08 02:41:11 -0800 | [diff] [blame] | 761 | static void __free_exceptions(struct dm_snapshot *s) |
| 762 | { |
Heinz Mauelshagen | eb69aca | 2008-04-24 21:43:19 +0100 | [diff] [blame] | 763 | dm_kcopyd_client_destroy(s->kcopyd_client); |
Milan Broz | 31c93a0 | 2006-12-08 02:41:11 -0800 | [diff] [blame] | 764 | s->kcopyd_client = NULL; |
| 765 | |
Jon Brassow | 3510cb9 | 2009-12-10 23:52:11 +0000 | [diff] [blame] | 766 | dm_exception_table_exit(&s->pending, pending_cache); |
| 767 | dm_exception_table_exit(&s->complete, exception_cache); |
Milan Broz | 31c93a0 | 2006-12-08 02:41:11 -0800 | [diff] [blame] | 768 | } |
| 769 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 770 | static void snapshot_dtr(struct dm_target *ti) |
| 771 | { |
Mikulas Patocka | cd45daf | 2008-07-21 12:00:32 +0100 | [diff] [blame] | 772 | #ifdef CONFIG_DM_DEBUG |
| 773 | int i; |
| 774 | #endif |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 775 | struct dm_snapshot *s = ti->private; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 776 | |
Alasdair G Kergon | ca3a931 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 777 | flush_workqueue(ksnapd); |
| 778 | |
Alasdair G Kergon | 138728dc | 2006-03-27 01:17:50 -0800 | [diff] [blame] | 779 | /* Prevent further origin writes from using this snapshot. */ |
| 780 | /* After this returns there can be no new kcopyd jobs. */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 781 | unregister_snapshot(s); |
| 782 | |
Mikulas Patocka | 879129d2 | 2008-10-30 13:33:16 +0000 | [diff] [blame] | 783 | while (atomic_read(&s->pending_exceptions_count)) |
Mikulas Patocka | 90fa152 | 2009-01-06 03:04:54 +0000 | [diff] [blame] | 784 | msleep(1); |
Mikulas Patocka | 879129d2 | 2008-10-30 13:33:16 +0000 | [diff] [blame] | 785 | /* |
| 786 | * Ensure instructions in mempool_destroy aren't reordered |
| 787 | * before atomic_read. |
| 788 | */ |
| 789 | smp_mb(); |
| 790 | |
Mikulas Patocka | cd45daf | 2008-07-21 12:00:32 +0100 | [diff] [blame] | 791 | #ifdef CONFIG_DM_DEBUG |
| 792 | for (i = 0; i < DM_TRACKED_CHUNK_HASH_SIZE; i++) |
| 793 | BUG_ON(!hlist_empty(&s->tracked_chunk_hash[i])); |
| 794 | #endif |
| 795 | |
| 796 | mempool_destroy(s->tracked_chunk_pool); |
| 797 | |
Milan Broz | 31c93a0 | 2006-12-08 02:41:11 -0800 | [diff] [blame] | 798 | __free_exceptions(s); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 799 | |
Mikulas Patocka | 92e8681 | 2008-07-21 12:00:35 +0100 | [diff] [blame] | 800 | mempool_destroy(s->pending_pool); |
| 801 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 802 | dm_put_device(ti, s->origin); |
Jonathan Brassow | fee1998 | 2009-04-02 19:55:34 +0100 | [diff] [blame] | 803 | |
| 804 | dm_exception_store_destroy(s->store); |
Alasdair G Kergon | 138728dc | 2006-03-27 01:17:50 -0800 | [diff] [blame] | 805 | |
Mike Snitzer | fc56f6f | 2009-12-10 23:52:12 +0000 | [diff] [blame] | 806 | dm_put_device(ti, s->cow); |
| 807 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 808 | kfree(s); |
| 809 | } |
| 810 | |
| 811 | /* |
| 812 | * Flush a list of buffers. |
| 813 | */ |
| 814 | static void flush_bios(struct bio *bio) |
| 815 | { |
| 816 | struct bio *n; |
| 817 | |
| 818 | while (bio) { |
| 819 | n = bio->bi_next; |
| 820 | bio->bi_next = NULL; |
| 821 | generic_make_request(bio); |
| 822 | bio = n; |
| 823 | } |
| 824 | } |
| 825 | |
David Howells | c402895 | 2006-11-22 14:57:56 +0000 | [diff] [blame] | 826 | static void flush_queued_bios(struct work_struct *work) |
Alasdair G Kergon | ca3a931 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 827 | { |
David Howells | c402895 | 2006-11-22 14:57:56 +0000 | [diff] [blame] | 828 | struct dm_snapshot *s = |
| 829 | container_of(work, struct dm_snapshot, queued_bios_work); |
Alasdair G Kergon | ca3a931 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 830 | struct bio *queued_bios; |
| 831 | unsigned long flags; |
| 832 | |
| 833 | spin_lock_irqsave(&s->pe_lock, flags); |
| 834 | queued_bios = bio_list_get(&s->queued_bios); |
| 835 | spin_unlock_irqrestore(&s->pe_lock, flags); |
| 836 | |
| 837 | flush_bios(queued_bios); |
| 838 | } |
| 839 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 840 | /* |
| 841 | * Error a list of buffers. |
| 842 | */ |
| 843 | static void error_bios(struct bio *bio) |
| 844 | { |
| 845 | struct bio *n; |
| 846 | |
| 847 | while (bio) { |
| 848 | n = bio->bi_next; |
| 849 | bio->bi_next = NULL; |
NeilBrown | 6712ecf | 2007-09-27 12:47:43 +0200 | [diff] [blame] | 850 | bio_io_error(bio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 851 | bio = n; |
| 852 | } |
| 853 | } |
| 854 | |
Alasdair G Kergon | 695368a | 2006-10-03 01:15:31 -0700 | [diff] [blame] | 855 | static void __invalidate_snapshot(struct dm_snapshot *s, int err) |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 856 | { |
| 857 | if (!s->valid) |
| 858 | return; |
| 859 | |
| 860 | if (err == -EIO) |
| 861 | DMERR("Invalidating snapshot: Error reading/writing."); |
| 862 | else if (err == -ENOMEM) |
| 863 | DMERR("Invalidating snapshot: Unable to allocate exception."); |
| 864 | |
Jonathan Brassow | 493df71 | 2009-04-02 19:55:31 +0100 | [diff] [blame] | 865 | if (s->store->type->drop_snapshot) |
| 866 | s->store->type->drop_snapshot(s->store); |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 867 | |
| 868 | s->valid = 0; |
| 869 | |
Mike Snitzer | fc56f6f | 2009-12-10 23:52:12 +0000 | [diff] [blame] | 870 | dm_table_event(s->ti->table); |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 871 | } |
| 872 | |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 873 | static void get_pending_exception(struct dm_snap_pending_exception *pe) |
Alasdair G Kergon | 4b832e8 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 874 | { |
| 875 | atomic_inc(&pe->ref_count); |
| 876 | } |
| 877 | |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 878 | 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] | 879 | { |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 880 | struct dm_snap_pending_exception *primary_pe; |
Alasdair G Kergon | 4b832e8 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 881 | struct bio *origin_bios = NULL; |
| 882 | |
| 883 | primary_pe = pe->primary_pe; |
| 884 | |
| 885 | /* |
| 886 | * If this pe is involved in a write to the origin and |
| 887 | * it is the last sibling to complete then release |
| 888 | * the bios for the original write to the origin. |
| 889 | */ |
| 890 | if (primary_pe && |
Mikulas Patocka | 7c5f78b | 2008-10-21 17:44:51 +0100 | [diff] [blame] | 891 | atomic_dec_and_test(&primary_pe->ref_count)) { |
Alasdair G Kergon | 4b832e8 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 892 | origin_bios = bio_list_get(&primary_pe->origin_bios); |
Mikulas Patocka | 7c5f78b | 2008-10-21 17:44:51 +0100 | [diff] [blame] | 893 | free_pending_exception(primary_pe); |
| 894 | } |
Alasdair G Kergon | 4b832e8 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 895 | |
| 896 | /* |
| 897 | * Free the pe if it's not linked to an origin write or if |
| 898 | * it's not itself a primary pe. |
| 899 | */ |
| 900 | if (!primary_pe || primary_pe != pe) |
| 901 | free_pending_exception(pe); |
| 902 | |
Alasdair G Kergon | 4b832e8 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 903 | return origin_bios; |
| 904 | } |
| 905 | |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 906 | static void pending_complete(struct dm_snap_pending_exception *pe, int success) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 907 | { |
Jon Brassow | 1d4989c | 2009-12-10 23:52:10 +0000 | [diff] [blame] | 908 | struct dm_exception *e; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 909 | struct dm_snapshot *s = pe->snap; |
Alasdair G Kergon | 9d493fa | 2006-10-03 01:15:29 -0700 | [diff] [blame] | 910 | struct bio *origin_bios = NULL; |
| 911 | struct bio *snapshot_bios = NULL; |
| 912 | int error = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 913 | |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 914 | if (!success) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 915 | /* Read/write error - snapshot is unusable */ |
| 916 | down_write(&s->lock); |
Alasdair G Kergon | 695368a | 2006-10-03 01:15:31 -0700 | [diff] [blame] | 917 | __invalidate_snapshot(s, -EIO); |
Alasdair G Kergon | 9d493fa | 2006-10-03 01:15:29 -0700 | [diff] [blame] | 918 | error = 1; |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 919 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 920 | } |
| 921 | |
Jon Brassow | 3510cb9 | 2009-12-10 23:52:11 +0000 | [diff] [blame] | 922 | e = alloc_completed_exception(); |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 923 | if (!e) { |
| 924 | down_write(&s->lock); |
Alasdair G Kergon | 695368a | 2006-10-03 01:15:31 -0700 | [diff] [blame] | 925 | __invalidate_snapshot(s, -ENOMEM); |
Alasdair G Kergon | 9d493fa | 2006-10-03 01:15:29 -0700 | [diff] [blame] | 926 | error = 1; |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 927 | goto out; |
| 928 | } |
| 929 | *e = pe->e; |
| 930 | |
Alasdair G Kergon | 9d493fa | 2006-10-03 01:15:29 -0700 | [diff] [blame] | 931 | down_write(&s->lock); |
| 932 | if (!s->valid) { |
Jon Brassow | 3510cb9 | 2009-12-10 23:52:11 +0000 | [diff] [blame] | 933 | free_completed_exception(e); |
Alasdair G Kergon | 9d493fa | 2006-10-03 01:15:29 -0700 | [diff] [blame] | 934 | error = 1; |
| 935 | goto out; |
| 936 | } |
| 937 | |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 938 | /* |
Mikulas Patocka | a8d41b5 | 2008-07-21 12:00:34 +0100 | [diff] [blame] | 939 | * Check for conflicting reads. This is extremely improbable, |
Mikulas Patocka | 90fa152 | 2009-01-06 03:04:54 +0000 | [diff] [blame] | 940 | * so msleep(1) is sufficient and there is no need for a wait queue. |
Mikulas Patocka | a8d41b5 | 2008-07-21 12:00:34 +0100 | [diff] [blame] | 941 | */ |
| 942 | while (__chunk_is_tracked(s, pe->e.old_chunk)) |
Mikulas Patocka | 90fa152 | 2009-01-06 03:04:54 +0000 | [diff] [blame] | 943 | msleep(1); |
Mikulas Patocka | a8d41b5 | 2008-07-21 12:00:34 +0100 | [diff] [blame] | 944 | |
| 945 | /* |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 946 | * Add a proper exception, and remove the |
| 947 | * in-flight exception from the list. |
| 948 | */ |
Jon Brassow | 3510cb9 | 2009-12-10 23:52:11 +0000 | [diff] [blame] | 949 | dm_insert_exception(&s->complete, e); |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 950 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 951 | out: |
Jon Brassow | 3510cb9 | 2009-12-10 23:52:11 +0000 | [diff] [blame] | 952 | dm_remove_exception(&pe->e); |
Alasdair G Kergon | 9d493fa | 2006-10-03 01:15:29 -0700 | [diff] [blame] | 953 | snapshot_bios = bio_list_get(&pe->snapshot_bios); |
Alasdair G Kergon | 4b832e8 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 954 | origin_bios = put_pending_exception(pe); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 955 | |
Alasdair G Kergon | 9d493fa | 2006-10-03 01:15:29 -0700 | [diff] [blame] | 956 | up_write(&s->lock); |
| 957 | |
| 958 | /* Submit any pending write bios */ |
| 959 | if (error) |
| 960 | error_bios(snapshot_bios); |
| 961 | else |
| 962 | flush_bios(snapshot_bios); |
| 963 | |
| 964 | flush_bios(origin_bios); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 965 | } |
| 966 | |
| 967 | static void commit_callback(void *context, int success) |
| 968 | { |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 969 | struct dm_snap_pending_exception *pe = context; |
| 970 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 971 | pending_complete(pe, success); |
| 972 | } |
| 973 | |
| 974 | /* |
| 975 | * Called when the copy I/O has finished. kcopyd actually runs |
| 976 | * this code so don't block. |
| 977 | */ |
Alasdair G Kergon | 4cdc1d1 | 2008-03-28 14:16:10 -0700 | [diff] [blame] | 978 | static void copy_callback(int read_err, unsigned long write_err, void *context) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 979 | { |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 980 | struct dm_snap_pending_exception *pe = context; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 981 | struct dm_snapshot *s = pe->snap; |
| 982 | |
| 983 | if (read_err || write_err) |
| 984 | pending_complete(pe, 0); |
| 985 | |
| 986 | else |
| 987 | /* Update the metadata if we are persistent */ |
Jonathan Brassow | 493df71 | 2009-04-02 19:55:31 +0100 | [diff] [blame] | 988 | s->store->type->commit_exception(s->store, &pe->e, |
| 989 | commit_callback, pe); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 990 | } |
| 991 | |
| 992 | /* |
| 993 | * Dispatches the copy operation to kcopyd. |
| 994 | */ |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 995 | static void start_copy(struct dm_snap_pending_exception *pe) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 996 | { |
| 997 | struct dm_snapshot *s = pe->snap; |
Heinz Mauelshagen | 22a1ceb | 2008-04-24 21:43:17 +0100 | [diff] [blame] | 998 | struct dm_io_region src, dest; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 999 | struct block_device *bdev = s->origin->bdev; |
| 1000 | sector_t dev_size; |
| 1001 | |
| 1002 | dev_size = get_dev_size(bdev); |
| 1003 | |
| 1004 | src.bdev = bdev; |
Jonathan Brassow | 71fab00 | 2009-04-02 19:55:33 +0100 | [diff] [blame] | 1005 | src.sector = chunk_to_sector(s->store, pe->e.old_chunk); |
Mikulas Patocka | df96eee | 2009-10-16 23:18:17 +0100 | [diff] [blame] | 1006 | src.count = min((sector_t)s->store->chunk_size, dev_size - src.sector); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1007 | |
Mike Snitzer | fc56f6f | 2009-12-10 23:52:12 +0000 | [diff] [blame] | 1008 | dest.bdev = s->cow->bdev; |
Jonathan Brassow | 71fab00 | 2009-04-02 19:55:33 +0100 | [diff] [blame] | 1009 | dest.sector = chunk_to_sector(s->store, pe->e.new_chunk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1010 | dest.count = src.count; |
| 1011 | |
| 1012 | /* Hand over to kcopyd */ |
Heinz Mauelshagen | eb69aca | 2008-04-24 21:43:19 +0100 | [diff] [blame] | 1013 | dm_kcopyd_copy(s->kcopyd_client, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1014 | &src, 1, &dest, 0, copy_callback, pe); |
| 1015 | } |
| 1016 | |
Mikulas Patocka | 2913808 | 2009-04-02 19:55:25 +0100 | [diff] [blame] | 1017 | static struct dm_snap_pending_exception * |
| 1018 | __lookup_pending_exception(struct dm_snapshot *s, chunk_t chunk) |
| 1019 | { |
Jon Brassow | 3510cb9 | 2009-12-10 23:52:11 +0000 | [diff] [blame] | 1020 | struct dm_exception *e = dm_lookup_exception(&s->pending, chunk); |
Mikulas Patocka | 2913808 | 2009-04-02 19:55:25 +0100 | [diff] [blame] | 1021 | |
| 1022 | if (!e) |
| 1023 | return NULL; |
| 1024 | |
| 1025 | return container_of(e, struct dm_snap_pending_exception, e); |
| 1026 | } |
| 1027 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1028 | /* |
| 1029 | * Looks to see if this snapshot already has a pending exception |
| 1030 | * for this chunk, otherwise it allocates a new one and inserts |
| 1031 | * it into the pending table. |
| 1032 | * |
| 1033 | * NOTE: a write lock must be held on snap->lock before calling |
| 1034 | * this. |
| 1035 | */ |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 1036 | static struct dm_snap_pending_exception * |
Mikulas Patocka | c662139 | 2009-04-02 19:55:25 +0100 | [diff] [blame] | 1037 | __find_pending_exception(struct dm_snapshot *s, |
| 1038 | struct dm_snap_pending_exception *pe, chunk_t chunk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1039 | { |
Mikulas Patocka | c662139 | 2009-04-02 19:55:25 +0100 | [diff] [blame] | 1040 | struct dm_snap_pending_exception *pe2; |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 1041 | |
Mikulas Patocka | 2913808 | 2009-04-02 19:55:25 +0100 | [diff] [blame] | 1042 | pe2 = __lookup_pending_exception(s, chunk); |
| 1043 | if (pe2) { |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 1044 | free_pending_exception(pe); |
Mikulas Patocka | 2913808 | 2009-04-02 19:55:25 +0100 | [diff] [blame] | 1045 | return pe2; |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 1046 | } |
| 1047 | |
| 1048 | pe->e.old_chunk = chunk; |
| 1049 | bio_list_init(&pe->origin_bios); |
| 1050 | bio_list_init(&pe->snapshot_bios); |
| 1051 | pe->primary_pe = NULL; |
Alasdair G Kergon | 4b832e8 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 1052 | atomic_set(&pe->ref_count, 0); |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 1053 | pe->started = 0; |
| 1054 | |
Jonathan Brassow | 493df71 | 2009-04-02 19:55:31 +0100 | [diff] [blame] | 1055 | if (s->store->type->prepare_exception(s->store, &pe->e)) { |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 1056 | free_pending_exception(pe); |
| 1057 | return NULL; |
| 1058 | } |
| 1059 | |
Alasdair G Kergon | 4b832e8 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 1060 | get_pending_exception(pe); |
Jon Brassow | 3510cb9 | 2009-12-10 23:52:11 +0000 | [diff] [blame] | 1061 | dm_insert_exception(&s->pending, &pe->e); |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 1062 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1063 | return pe; |
| 1064 | } |
| 1065 | |
Jon Brassow | 1d4989c | 2009-12-10 23:52:10 +0000 | [diff] [blame] | 1066 | static void remap_exception(struct dm_snapshot *s, struct dm_exception *e, |
Milan Broz | d74f81f | 2008-02-08 02:11:27 +0000 | [diff] [blame] | 1067 | struct bio *bio, chunk_t chunk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1068 | { |
Mike Snitzer | fc56f6f | 2009-12-10 23:52:12 +0000 | [diff] [blame] | 1069 | bio->bi_bdev = s->cow->bdev; |
Jonathan Brassow | 71fab00 | 2009-04-02 19:55:33 +0100 | [diff] [blame] | 1070 | bio->bi_sector = chunk_to_sector(s->store, |
| 1071 | dm_chunk_number(e->new_chunk) + |
| 1072 | (chunk - e->old_chunk)) + |
| 1073 | (bio->bi_sector & |
| 1074 | s->store->chunk_mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1075 | } |
| 1076 | |
| 1077 | static int snapshot_map(struct dm_target *ti, struct bio *bio, |
| 1078 | union map_info *map_context) |
| 1079 | { |
Jon Brassow | 1d4989c | 2009-12-10 23:52:10 +0000 | [diff] [blame] | 1080 | struct dm_exception *e; |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 1081 | struct dm_snapshot *s = ti->private; |
Kiyoshi Ueda | d2a7ad2 | 2006-12-08 02:41:06 -0800 | [diff] [blame] | 1082 | int r = DM_MAPIO_REMAPPED; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1083 | chunk_t chunk; |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 1084 | struct dm_snap_pending_exception *pe = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1085 | |
Mikulas Patocka | 494b3ee | 2009-06-22 10:12:25 +0100 | [diff] [blame] | 1086 | if (unlikely(bio_empty_barrier(bio))) { |
Mike Snitzer | fc56f6f | 2009-12-10 23:52:12 +0000 | [diff] [blame] | 1087 | bio->bi_bdev = s->cow->bdev; |
Mikulas Patocka | 494b3ee | 2009-06-22 10:12:25 +0100 | [diff] [blame] | 1088 | return DM_MAPIO_REMAPPED; |
| 1089 | } |
| 1090 | |
Jonathan Brassow | 71fab00 | 2009-04-02 19:55:33 +0100 | [diff] [blame] | 1091 | chunk = sector_to_chunk(s->store, bio->bi_sector); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1092 | |
| 1093 | /* Full snapshots are not usable */ |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 1094 | /* 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] | 1095 | if (!s->valid) |
Alasdair G Kergon | f6a80ea | 2005-07-12 15:53:01 -0700 | [diff] [blame] | 1096 | return -EIO; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1097 | |
Alasdair G Kergon | ba40a2a | 2006-10-03 01:15:28 -0700 | [diff] [blame] | 1098 | /* FIXME: should only take write lock if we need |
| 1099 | * to copy an exception */ |
| 1100 | down_write(&s->lock); |
| 1101 | |
| 1102 | if (!s->valid) { |
| 1103 | r = -EIO; |
| 1104 | goto out_unlock; |
| 1105 | } |
| 1106 | |
| 1107 | /* If the block is already remapped - use that, else remap it */ |
Jon Brassow | 3510cb9 | 2009-12-10 23:52:11 +0000 | [diff] [blame] | 1108 | e = dm_lookup_exception(&s->complete, chunk); |
Alasdair G Kergon | ba40a2a | 2006-10-03 01:15:28 -0700 | [diff] [blame] | 1109 | if (e) { |
Milan Broz | d74f81f | 2008-02-08 02:11:27 +0000 | [diff] [blame] | 1110 | remap_exception(s, e, bio, chunk); |
Alasdair G Kergon | ba40a2a | 2006-10-03 01:15:28 -0700 | [diff] [blame] | 1111 | goto out_unlock; |
| 1112 | } |
| 1113 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1114 | /* |
| 1115 | * Write to snapshot - higher level takes care of RW/RO |
| 1116 | * flags so we should only get this if we are |
| 1117 | * writeable. |
| 1118 | */ |
| 1119 | if (bio_rw(bio) == WRITE) { |
Mikulas Patocka | 2913808 | 2009-04-02 19:55:25 +0100 | [diff] [blame] | 1120 | pe = __lookup_pending_exception(s, chunk); |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 1121 | if (!pe) { |
Mikulas Patocka | c662139 | 2009-04-02 19:55:25 +0100 | [diff] [blame] | 1122 | up_write(&s->lock); |
| 1123 | pe = alloc_pending_exception(s); |
| 1124 | down_write(&s->lock); |
| 1125 | |
| 1126 | if (!s->valid) { |
| 1127 | free_pending_exception(pe); |
| 1128 | r = -EIO; |
| 1129 | goto out_unlock; |
| 1130 | } |
| 1131 | |
Jon Brassow | 3510cb9 | 2009-12-10 23:52:11 +0000 | [diff] [blame] | 1132 | e = dm_lookup_exception(&s->complete, chunk); |
Mikulas Patocka | 35bf659 | 2009-04-02 19:55:26 +0100 | [diff] [blame] | 1133 | if (e) { |
| 1134 | free_pending_exception(pe); |
| 1135 | remap_exception(s, e, bio, chunk); |
| 1136 | goto out_unlock; |
| 1137 | } |
| 1138 | |
Mikulas Patocka | c662139 | 2009-04-02 19:55:25 +0100 | [diff] [blame] | 1139 | pe = __find_pending_exception(s, pe, chunk); |
Mikulas Patocka | 2913808 | 2009-04-02 19:55:25 +0100 | [diff] [blame] | 1140 | if (!pe) { |
| 1141 | __invalidate_snapshot(s, -ENOMEM); |
| 1142 | r = -EIO; |
| 1143 | goto out_unlock; |
| 1144 | } |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 1145 | } |
| 1146 | |
Milan Broz | d74f81f | 2008-02-08 02:11:27 +0000 | [diff] [blame] | 1147 | remap_exception(s, &pe->e, bio, chunk); |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 1148 | bio_list_add(&pe->snapshot_bios, bio); |
| 1149 | |
Kiyoshi Ueda | d2a7ad2 | 2006-12-08 02:41:06 -0800 | [diff] [blame] | 1150 | r = DM_MAPIO_SUBMITTED; |
Alasdair G Kergon | ba40a2a | 2006-10-03 01:15:28 -0700 | [diff] [blame] | 1151 | |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 1152 | if (!pe->started) { |
| 1153 | /* this is protected by snap->lock */ |
| 1154 | pe->started = 1; |
Alasdair G Kergon | ba40a2a | 2006-10-03 01:15:28 -0700 | [diff] [blame] | 1155 | up_write(&s->lock); |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 1156 | start_copy(pe); |
Alasdair G Kergon | ba40a2a | 2006-10-03 01:15:28 -0700 | [diff] [blame] | 1157 | goto out; |
| 1158 | } |
Mikulas Patocka | cd45daf | 2008-07-21 12:00:32 +0100 | [diff] [blame] | 1159 | } else { |
Alasdair G Kergon | ba40a2a | 2006-10-03 01:15:28 -0700 | [diff] [blame] | 1160 | bio->bi_bdev = s->origin->bdev; |
Mikulas Patocka | cd45daf | 2008-07-21 12:00:32 +0100 | [diff] [blame] | 1161 | map_context->ptr = track_chunk(s, chunk); |
| 1162 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1163 | |
Alasdair G Kergon | ba40a2a | 2006-10-03 01:15:28 -0700 | [diff] [blame] | 1164 | out_unlock: |
| 1165 | up_write(&s->lock); |
| 1166 | out: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1167 | return r; |
| 1168 | } |
| 1169 | |
Mikulas Patocka | cd45daf | 2008-07-21 12:00:32 +0100 | [diff] [blame] | 1170 | static int snapshot_end_io(struct dm_target *ti, struct bio *bio, |
| 1171 | int error, union map_info *map_context) |
| 1172 | { |
| 1173 | struct dm_snapshot *s = ti->private; |
| 1174 | struct dm_snap_tracked_chunk *c = map_context->ptr; |
| 1175 | |
| 1176 | if (c) |
| 1177 | stop_tracking_chunk(s, c); |
| 1178 | |
| 1179 | return 0; |
| 1180 | } |
| 1181 | |
Mike Snitzer | c26655c | 2009-12-10 23:52:12 +0000 | [diff] [blame] | 1182 | static void snapshot_postsuspend(struct dm_target *ti) |
| 1183 | { |
| 1184 | struct dm_snapshot *s = ti->private; |
| 1185 | |
| 1186 | down_write(&s->lock); |
| 1187 | s->suspended = 1; |
| 1188 | up_write(&s->lock); |
| 1189 | } |
| 1190 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1191 | static void snapshot_resume(struct dm_target *ti) |
| 1192 | { |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 1193 | struct dm_snapshot *s = ti->private; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1194 | |
Alasdair G Kergon | aa14ede | 2006-02-01 03:04:50 -0800 | [diff] [blame] | 1195 | down_write(&s->lock); |
| 1196 | s->active = 1; |
Mike Snitzer | c26655c | 2009-12-10 23:52:12 +0000 | [diff] [blame] | 1197 | s->suspended = 0; |
Alasdair G Kergon | aa14ede | 2006-02-01 03:04:50 -0800 | [diff] [blame] | 1198 | up_write(&s->lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1199 | } |
| 1200 | |
| 1201 | static int snapshot_status(struct dm_target *ti, status_type_t type, |
| 1202 | char *result, unsigned int maxlen) |
| 1203 | { |
Jonathan Brassow | 2e4a31d | 2009-04-02 19:55:34 +0100 | [diff] [blame] | 1204 | unsigned sz = 0; |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 1205 | struct dm_snapshot *snap = ti->private; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1206 | |
| 1207 | switch (type) { |
| 1208 | case STATUSTYPE_INFO: |
Mikulas Patocka | 94e76572 | 2009-12-10 23:51:53 +0000 | [diff] [blame] | 1209 | |
| 1210 | down_write(&snap->lock); |
| 1211 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1212 | if (!snap->valid) |
Jonathan Brassow | 2e4a31d | 2009-04-02 19:55:34 +0100 | [diff] [blame] | 1213 | DMEMIT("Invalid"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1214 | else { |
Mike Snitzer | 985903b | 2009-12-10 23:52:11 +0000 | [diff] [blame] | 1215 | if (snap->store->type->usage) { |
| 1216 | sector_t total_sectors, sectors_allocated, |
| 1217 | metadata_sectors; |
| 1218 | snap->store->type->usage(snap->store, |
| 1219 | &total_sectors, |
| 1220 | §ors_allocated, |
| 1221 | &metadata_sectors); |
| 1222 | DMEMIT("%llu/%llu %llu", |
| 1223 | (unsigned long long)sectors_allocated, |
| 1224 | (unsigned long long)total_sectors, |
| 1225 | (unsigned long long)metadata_sectors); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1226 | } |
| 1227 | else |
Jonathan Brassow | 2e4a31d | 2009-04-02 19:55:34 +0100 | [diff] [blame] | 1228 | DMEMIT("Unknown"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1229 | } |
Mikulas Patocka | 94e76572 | 2009-12-10 23:51:53 +0000 | [diff] [blame] | 1230 | |
| 1231 | up_write(&snap->lock); |
| 1232 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1233 | break; |
| 1234 | |
| 1235 | case STATUSTYPE_TABLE: |
| 1236 | /* |
| 1237 | * kdevname returns a static pointer so we need |
| 1238 | * to make private copies if the output is to |
| 1239 | * make sense. |
| 1240 | */ |
Mike Snitzer | fc56f6f | 2009-12-10 23:52:12 +0000 | [diff] [blame] | 1241 | DMEMIT("%s %s", snap->origin->name, snap->cow->name); |
Jonathan Brassow | 1e302a9 | 2009-04-02 19:55:35 +0100 | [diff] [blame] | 1242 | snap->store->type->status(snap->store, type, result + sz, |
| 1243 | maxlen - sz); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1244 | break; |
| 1245 | } |
| 1246 | |
| 1247 | return 0; |
| 1248 | } |
| 1249 | |
Mike Snitzer | 8811f46 | 2009-09-04 20:40:19 +0100 | [diff] [blame] | 1250 | static int snapshot_iterate_devices(struct dm_target *ti, |
| 1251 | iterate_devices_callout_fn fn, void *data) |
| 1252 | { |
| 1253 | struct dm_snapshot *snap = ti->private; |
| 1254 | |
| 1255 | return fn(ti, snap->origin, 0, ti->len, data); |
| 1256 | } |
| 1257 | |
| 1258 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1259 | /*----------------------------------------------------------------- |
| 1260 | * Origin methods |
| 1261 | *---------------------------------------------------------------*/ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1262 | static int __origin_write(struct list_head *snapshots, struct bio *bio) |
| 1263 | { |
Kiyoshi Ueda | d2a7ad2 | 2006-12-08 02:41:06 -0800 | [diff] [blame] | 1264 | int r = DM_MAPIO_REMAPPED, first = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1265 | struct dm_snapshot *snap; |
Jon Brassow | 1d4989c | 2009-12-10 23:52:10 +0000 | [diff] [blame] | 1266 | struct dm_exception *e; |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 1267 | struct dm_snap_pending_exception *pe, *next_pe, *primary_pe = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1268 | chunk_t chunk; |
Alasdair G Kergon | eccf081 | 2006-03-27 01:17:42 -0800 | [diff] [blame] | 1269 | LIST_HEAD(pe_queue); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1270 | |
| 1271 | /* Do all the snapshots on this origin */ |
| 1272 | list_for_each_entry (snap, snapshots, list) { |
| 1273 | |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 1274 | down_write(&snap->lock); |
| 1275 | |
Alasdair G Kergon | aa14ede | 2006-02-01 03:04:50 -0800 | [diff] [blame] | 1276 | /* Only deal with valid and active snapshots */ |
| 1277 | if (!snap->valid || !snap->active) |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 1278 | goto next_snapshot; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1279 | |
Alasdair G Kergon | d5e404c | 2005-07-12 15:53:05 -0700 | [diff] [blame] | 1280 | /* Nothing to do if writing beyond end of snapshot */ |
Mike Snitzer | fc56f6f | 2009-12-10 23:52:12 +0000 | [diff] [blame] | 1281 | if (bio->bi_sector >= dm_table_get_size(snap->ti->table)) |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 1282 | goto next_snapshot; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1283 | |
| 1284 | /* |
| 1285 | * Remember, different snapshots can have |
| 1286 | * different chunk sizes. |
| 1287 | */ |
Jonathan Brassow | 71fab00 | 2009-04-02 19:55:33 +0100 | [diff] [blame] | 1288 | chunk = sector_to_chunk(snap->store, bio->bi_sector); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1289 | |
| 1290 | /* |
| 1291 | * Check exception table to see if block |
| 1292 | * is already remapped in this snapshot |
| 1293 | * and trigger an exception if not. |
Alasdair G Kergon | b4b610f | 2006-03-27 01:17:44 -0800 | [diff] [blame] | 1294 | * |
Alasdair G Kergon | 4b832e8 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 1295 | * ref_count is initialised to 1 so pending_complete() |
Alasdair G Kergon | b4b610f | 2006-03-27 01:17:44 -0800 | [diff] [blame] | 1296 | * won't destroy the primary_pe while we're inside this loop. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1297 | */ |
Jon Brassow | 3510cb9 | 2009-12-10 23:52:11 +0000 | [diff] [blame] | 1298 | e = dm_lookup_exception(&snap->complete, chunk); |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 1299 | if (e) |
| 1300 | goto next_snapshot; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1301 | |
Mikulas Patocka | 2913808 | 2009-04-02 19:55:25 +0100 | [diff] [blame] | 1302 | pe = __lookup_pending_exception(snap, chunk); |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 1303 | if (!pe) { |
Mikulas Patocka | c662139 | 2009-04-02 19:55:25 +0100 | [diff] [blame] | 1304 | up_write(&snap->lock); |
| 1305 | pe = alloc_pending_exception(snap); |
| 1306 | down_write(&snap->lock); |
| 1307 | |
| 1308 | if (!snap->valid) { |
| 1309 | free_pending_exception(pe); |
| 1310 | goto next_snapshot; |
| 1311 | } |
| 1312 | |
Jon Brassow | 3510cb9 | 2009-12-10 23:52:11 +0000 | [diff] [blame] | 1313 | e = dm_lookup_exception(&snap->complete, chunk); |
Mikulas Patocka | 35bf659 | 2009-04-02 19:55:26 +0100 | [diff] [blame] | 1314 | if (e) { |
| 1315 | free_pending_exception(pe); |
| 1316 | goto next_snapshot; |
| 1317 | } |
| 1318 | |
Mikulas Patocka | c662139 | 2009-04-02 19:55:25 +0100 | [diff] [blame] | 1319 | pe = __find_pending_exception(snap, pe, chunk); |
Mikulas Patocka | 2913808 | 2009-04-02 19:55:25 +0100 | [diff] [blame] | 1320 | if (!pe) { |
| 1321 | __invalidate_snapshot(snap, -ENOMEM); |
| 1322 | goto next_snapshot; |
| 1323 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1324 | } |
| 1325 | |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 1326 | if (!primary_pe) { |
| 1327 | /* |
| 1328 | * Either every pe here has same |
| 1329 | * primary_pe or none has one yet. |
| 1330 | */ |
| 1331 | if (pe->primary_pe) |
| 1332 | primary_pe = pe->primary_pe; |
| 1333 | else { |
| 1334 | primary_pe = pe; |
| 1335 | first = 1; |
| 1336 | } |
| 1337 | |
| 1338 | bio_list_add(&primary_pe->origin_bios, bio); |
| 1339 | |
Kiyoshi Ueda | d2a7ad2 | 2006-12-08 02:41:06 -0800 | [diff] [blame] | 1340 | r = DM_MAPIO_SUBMITTED; |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 1341 | } |
| 1342 | |
| 1343 | if (!pe->primary_pe) { |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 1344 | pe->primary_pe = primary_pe; |
Alasdair G Kergon | 4b832e8 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 1345 | get_pending_exception(primary_pe); |
Alasdair G Kergon | 76df1c6 | 2006-03-27 01:17:45 -0800 | [diff] [blame] | 1346 | } |
| 1347 | |
| 1348 | if (!pe->started) { |
| 1349 | pe->started = 1; |
| 1350 | list_add_tail(&pe->list, &pe_queue); |
| 1351 | } |
| 1352 | |
| 1353 | next_snapshot: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1354 | up_write(&snap->lock); |
| 1355 | } |
| 1356 | |
Alasdair G Kergon | b4b610f | 2006-03-27 01:17:44 -0800 | [diff] [blame] | 1357 | if (!primary_pe) |
Alasdair G Kergon | 4b832e8 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 1358 | return r; |
Alasdair G Kergon | b4b610f | 2006-03-27 01:17:44 -0800 | [diff] [blame] | 1359 | |
| 1360 | /* |
| 1361 | * 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] | 1362 | * ref_count is now 1 it means all the pending exceptions |
Alasdair G Kergon | b4b610f | 2006-03-27 01:17:44 -0800 | [diff] [blame] | 1363 | * got completed while we were in the loop above, so it falls to |
| 1364 | * us here to remove the primary_pe and submit any origin_bios. |
| 1365 | */ |
| 1366 | |
Alasdair G Kergon | 4b832e8 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 1367 | if (first && atomic_dec_and_test(&primary_pe->ref_count)) { |
Alasdair G Kergon | b4b610f | 2006-03-27 01:17:44 -0800 | [diff] [blame] | 1368 | flush_bios(bio_list_get(&primary_pe->origin_bios)); |
| 1369 | free_pending_exception(primary_pe); |
| 1370 | /* If we got here, pe_queue is necessarily empty. */ |
Alasdair G Kergon | 4b832e8 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 1371 | return r; |
Alasdair G Kergon | b4b610f | 2006-03-27 01:17:44 -0800 | [diff] [blame] | 1372 | } |
| 1373 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1374 | /* |
| 1375 | * Now that we have a complete pe list we can start the copying. |
| 1376 | */ |
Alasdair G Kergon | eccf081 | 2006-03-27 01:17:42 -0800 | [diff] [blame] | 1377 | list_for_each_entry_safe(pe, next_pe, &pe_queue, list) |
| 1378 | start_copy(pe); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1379 | |
| 1380 | return r; |
| 1381 | } |
| 1382 | |
| 1383 | /* |
| 1384 | * Called on a write from the origin driver. |
| 1385 | */ |
| 1386 | static int do_origin(struct dm_dev *origin, struct bio *bio) |
| 1387 | { |
| 1388 | struct origin *o; |
Kiyoshi Ueda | d2a7ad2 | 2006-12-08 02:41:06 -0800 | [diff] [blame] | 1389 | int r = DM_MAPIO_REMAPPED; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1390 | |
| 1391 | down_read(&_origins_lock); |
| 1392 | o = __lookup_origin(origin->bdev); |
| 1393 | if (o) |
| 1394 | r = __origin_write(&o->snapshots, bio); |
| 1395 | up_read(&_origins_lock); |
| 1396 | |
| 1397 | return r; |
| 1398 | } |
| 1399 | |
| 1400 | /* |
| 1401 | * Origin: maps a linear range of a device, with hooks for snapshotting. |
| 1402 | */ |
| 1403 | |
| 1404 | /* |
| 1405 | * Construct an origin mapping: <dev_path> |
| 1406 | * The context for an origin is merely a 'struct dm_dev *' |
| 1407 | * pointing to the real device. |
| 1408 | */ |
| 1409 | static int origin_ctr(struct dm_target *ti, unsigned int argc, char **argv) |
| 1410 | { |
| 1411 | int r; |
| 1412 | struct dm_dev *dev; |
| 1413 | |
| 1414 | if (argc != 1) { |
Alasdair G Kergon | 72d9486 | 2006-06-26 00:27:35 -0700 | [diff] [blame] | 1415 | ti->error = "origin: incorrect number of arguments"; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1416 | return -EINVAL; |
| 1417 | } |
| 1418 | |
| 1419 | r = dm_get_device(ti, argv[0], 0, ti->len, |
| 1420 | dm_table_get_mode(ti->table), &dev); |
| 1421 | if (r) { |
| 1422 | ti->error = "Cannot get target device"; |
| 1423 | return r; |
| 1424 | } |
| 1425 | |
| 1426 | ti->private = dev; |
Mikulas Patocka | 494b3ee | 2009-06-22 10:12:25 +0100 | [diff] [blame] | 1427 | ti->num_flush_requests = 1; |
| 1428 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1429 | return 0; |
| 1430 | } |
| 1431 | |
| 1432 | static void origin_dtr(struct dm_target *ti) |
| 1433 | { |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 1434 | struct dm_dev *dev = ti->private; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1435 | dm_put_device(ti, dev); |
| 1436 | } |
| 1437 | |
| 1438 | static int origin_map(struct dm_target *ti, struct bio *bio, |
| 1439 | union map_info *map_context) |
| 1440 | { |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 1441 | struct dm_dev *dev = ti->private; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1442 | bio->bi_bdev = dev->bdev; |
| 1443 | |
Mikulas Patocka | 494b3ee | 2009-06-22 10:12:25 +0100 | [diff] [blame] | 1444 | if (unlikely(bio_empty_barrier(bio))) |
| 1445 | return DM_MAPIO_REMAPPED; |
| 1446 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1447 | /* Only tell snapshots if this is a write */ |
Kiyoshi Ueda | d2a7ad2 | 2006-12-08 02:41:06 -0800 | [diff] [blame] | 1448 | return (bio_rw(bio) == WRITE) ? do_origin(dev, bio) : DM_MAPIO_REMAPPED; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1449 | } |
| 1450 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1451 | /* |
| 1452 | * Set the target "split_io" field to the minimum of all the snapshots' |
| 1453 | * chunk sizes. |
| 1454 | */ |
| 1455 | static void origin_resume(struct dm_target *ti) |
| 1456 | { |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 1457 | struct dm_dev *dev = ti->private; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1458 | |
| 1459 | down_read(&_origins_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1460 | |
Mikulas Patocka | 7e201b3 | 2009-12-10 23:52:08 +0000 | [diff] [blame] | 1461 | ti->split_io = __minimum_chunk_size(__lookup_origin(dev->bdev)); |
| 1462 | |
| 1463 | up_read(&_origins_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1464 | } |
| 1465 | |
| 1466 | static int origin_status(struct dm_target *ti, status_type_t type, char *result, |
| 1467 | unsigned int maxlen) |
| 1468 | { |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 1469 | struct dm_dev *dev = ti->private; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1470 | |
| 1471 | switch (type) { |
| 1472 | case STATUSTYPE_INFO: |
| 1473 | result[0] = '\0'; |
| 1474 | break; |
| 1475 | |
| 1476 | case STATUSTYPE_TABLE: |
| 1477 | snprintf(result, maxlen, "%s", dev->name); |
| 1478 | break; |
| 1479 | } |
| 1480 | |
| 1481 | return 0; |
| 1482 | } |
| 1483 | |
Mike Snitzer | 8811f46 | 2009-09-04 20:40:19 +0100 | [diff] [blame] | 1484 | static int origin_iterate_devices(struct dm_target *ti, |
| 1485 | iterate_devices_callout_fn fn, void *data) |
| 1486 | { |
| 1487 | struct dm_dev *dev = ti->private; |
| 1488 | |
| 1489 | return fn(ti, dev, 0, ti->len, data); |
| 1490 | } |
| 1491 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1492 | static struct target_type origin_target = { |
| 1493 | .name = "snapshot-origin", |
Mike Snitzer | 8811f46 | 2009-09-04 20:40:19 +0100 | [diff] [blame] | 1494 | .version = {1, 7, 0}, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1495 | .module = THIS_MODULE, |
| 1496 | .ctr = origin_ctr, |
| 1497 | .dtr = origin_dtr, |
| 1498 | .map = origin_map, |
| 1499 | .resume = origin_resume, |
| 1500 | .status = origin_status, |
Mike Snitzer | 8811f46 | 2009-09-04 20:40:19 +0100 | [diff] [blame] | 1501 | .iterate_devices = origin_iterate_devices, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1502 | }; |
| 1503 | |
| 1504 | static struct target_type snapshot_target = { |
| 1505 | .name = "snapshot", |
Mike Snitzer | c26655c | 2009-12-10 23:52:12 +0000 | [diff] [blame] | 1506 | .version = {1, 9, 0}, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1507 | .module = THIS_MODULE, |
| 1508 | .ctr = snapshot_ctr, |
| 1509 | .dtr = snapshot_dtr, |
| 1510 | .map = snapshot_map, |
Mikulas Patocka | cd45daf | 2008-07-21 12:00:32 +0100 | [diff] [blame] | 1511 | .end_io = snapshot_end_io, |
Mike Snitzer | c26655c | 2009-12-10 23:52:12 +0000 | [diff] [blame] | 1512 | .postsuspend = snapshot_postsuspend, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1513 | .resume = snapshot_resume, |
| 1514 | .status = snapshot_status, |
Mike Snitzer | 8811f46 | 2009-09-04 20:40:19 +0100 | [diff] [blame] | 1515 | .iterate_devices = snapshot_iterate_devices, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1516 | }; |
| 1517 | |
| 1518 | static int __init dm_snapshot_init(void) |
| 1519 | { |
| 1520 | int r; |
| 1521 | |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 1522 | r = dm_exception_store_init(); |
| 1523 | if (r) { |
| 1524 | DMERR("Failed to initialize exception stores"); |
| 1525 | return r; |
| 1526 | } |
| 1527 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1528 | r = dm_register_target(&snapshot_target); |
| 1529 | if (r) { |
| 1530 | DMERR("snapshot target register failed %d", r); |
Jonathan Brassow | 034a186 | 2009-10-16 23:18:14 +0100 | [diff] [blame] | 1531 | goto bad_register_snapshot_target; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1532 | } |
| 1533 | |
| 1534 | r = dm_register_target(&origin_target); |
| 1535 | if (r < 0) { |
Alasdair G Kergon | 72d9486 | 2006-06-26 00:27:35 -0700 | [diff] [blame] | 1536 | DMERR("Origin target register failed %d", r); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1537 | goto bad1; |
| 1538 | } |
| 1539 | |
| 1540 | r = init_origin_hash(); |
| 1541 | if (r) { |
| 1542 | DMERR("init_origin_hash failed."); |
| 1543 | goto bad2; |
| 1544 | } |
| 1545 | |
Jon Brassow | 1d4989c | 2009-12-10 23:52:10 +0000 | [diff] [blame] | 1546 | exception_cache = KMEM_CACHE(dm_exception, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1547 | if (!exception_cache) { |
| 1548 | DMERR("Couldn't create exception cache."); |
| 1549 | r = -ENOMEM; |
| 1550 | goto bad3; |
| 1551 | } |
| 1552 | |
Alasdair G Kergon | 028867a | 2007-07-12 17:26:32 +0100 | [diff] [blame] | 1553 | pending_cache = KMEM_CACHE(dm_snap_pending_exception, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1554 | if (!pending_cache) { |
| 1555 | DMERR("Couldn't create pending cache."); |
| 1556 | r = -ENOMEM; |
| 1557 | goto bad4; |
| 1558 | } |
| 1559 | |
Mikulas Patocka | cd45daf | 2008-07-21 12:00:32 +0100 | [diff] [blame] | 1560 | tracked_chunk_cache = KMEM_CACHE(dm_snap_tracked_chunk, 0); |
| 1561 | if (!tracked_chunk_cache) { |
| 1562 | DMERR("Couldn't create cache to track chunks in use."); |
| 1563 | r = -ENOMEM; |
| 1564 | goto bad5; |
| 1565 | } |
| 1566 | |
Alasdair G Kergon | ca3a931 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 1567 | ksnapd = create_singlethread_workqueue("ksnapd"); |
| 1568 | if (!ksnapd) { |
| 1569 | DMERR("Failed to create ksnapd workqueue."); |
| 1570 | r = -ENOMEM; |
Mikulas Patocka | 92e8681 | 2008-07-21 12:00:35 +0100 | [diff] [blame] | 1571 | goto bad_pending_pool; |
Alasdair G Kergon | ca3a931 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 1572 | } |
| 1573 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1574 | return 0; |
| 1575 | |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 1576 | bad_pending_pool: |
Mikulas Patocka | cd45daf | 2008-07-21 12:00:32 +0100 | [diff] [blame] | 1577 | kmem_cache_destroy(tracked_chunk_cache); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 1578 | bad5: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1579 | kmem_cache_destroy(pending_cache); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 1580 | bad4: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1581 | kmem_cache_destroy(exception_cache); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 1582 | bad3: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1583 | exit_origin_hash(); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 1584 | bad2: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1585 | dm_unregister_target(&origin_target); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 1586 | bad1: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1587 | dm_unregister_target(&snapshot_target); |
Jonathan Brassow | 034a186 | 2009-10-16 23:18:14 +0100 | [diff] [blame] | 1588 | |
| 1589 | bad_register_snapshot_target: |
| 1590 | dm_exception_store_exit(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1591 | return r; |
| 1592 | } |
| 1593 | |
| 1594 | static void __exit dm_snapshot_exit(void) |
| 1595 | { |
Alasdair G Kergon | ca3a931 | 2006-10-03 01:15:30 -0700 | [diff] [blame] | 1596 | destroy_workqueue(ksnapd); |
| 1597 | |
Mikulas Patocka | 10d3bd0 | 2009-01-06 03:04:58 +0000 | [diff] [blame] | 1598 | dm_unregister_target(&snapshot_target); |
| 1599 | dm_unregister_target(&origin_target); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1600 | |
| 1601 | exit_origin_hash(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1602 | kmem_cache_destroy(pending_cache); |
| 1603 | kmem_cache_destroy(exception_cache); |
Mikulas Patocka | cd45daf | 2008-07-21 12:00:32 +0100 | [diff] [blame] | 1604 | kmem_cache_destroy(tracked_chunk_cache); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 1605 | |
| 1606 | dm_exception_store_exit(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1607 | } |
| 1608 | |
| 1609 | /* Module hooks */ |
| 1610 | module_init(dm_snapshot_init); |
| 1611 | module_exit(dm_snapshot_exit); |
| 1612 | |
| 1613 | MODULE_DESCRIPTION(DM_NAME " snapshot target"); |
| 1614 | MODULE_AUTHOR("Joe Thornber"); |
| 1615 | MODULE_LICENSE("GPL"); |