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Commit fa4d683af3693863bec761e2761a07e4c1351f86

Authored by Wei Yongjun
Committed by Alasdair G Kergon
1 parent d793e68427
Exists in smarc-l5.0.0_1.0.0-ga and in 5 other branches imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga

dm cache: fix error return code in cache_create 

Return -ENOMEM if memory allocation fails in cache_create
instead of 0 (to avoid NULL pointer dereference).

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Cc: stable@vger.kernel.org
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

Showing 1 changed file with 1 additions and 0 deletions Inline Diff

drivers/md/dm-cache-target.c
Diff comments   View file @ fa4d683
1 /* 1 /*
2 * Copyright (C) 2012 Red Hat. All rights reserved. 2 * Copyright (C) 2012 Red Hat. All rights reserved.
3 * 3 *
4 * This file is released under the GPL. 4 * This file is released under the GPL.
5 */ 5 */
6 6
7 #include "dm.h" 7 #include "dm.h"
8 #include "dm-bio-prison.h" 8 #include "dm-bio-prison.h"
9 #include "dm-bio-record.h" 9 #include "dm-bio-record.h"
10 #include "dm-cache-metadata.h" 10 #include "dm-cache-metadata.h"
11 11
12 #include <linux/dm-io.h> 12 #include <linux/dm-io.h>
13 #include <linux/dm-kcopyd.h> 13 #include <linux/dm-kcopyd.h>
14 #include <linux/init.h> 14 #include <linux/init.h>
15 #include <linux/mempool.h> 15 #include <linux/mempool.h>
16 #include <linux/module.h> 16 #include <linux/module.h>
17 #include <linux/slab.h> 17 #include <linux/slab.h>
18 #include <linux/vmalloc.h> 18 #include <linux/vmalloc.h>
19 19
20 #define DM_MSG_PREFIX "cache" 20 #define DM_MSG_PREFIX "cache"
21 21
22 DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(cache_copy_throttle, 22 DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(cache_copy_throttle,
23 "A percentage of time allocated for copying to and/or from cache"); 23 "A percentage of time allocated for copying to and/or from cache");
24 24
25 /*----------------------------------------------------------------*/ 25 /*----------------------------------------------------------------*/
26 26
27 /* 27 /*
28 * Glossary: 28 * Glossary:
29 * 29 *
30 * oblock: index of an origin block 30 * oblock: index of an origin block
31 * cblock: index of a cache block 31 * cblock: index of a cache block
32 * promotion: movement of a block from origin to cache 32 * promotion: movement of a block from origin to cache
33 * demotion: movement of a block from cache to origin 33 * demotion: movement of a block from cache to origin
34 * migration: movement of a block between the origin and cache device, 34 * migration: movement of a block between the origin and cache device,
35 * either direction 35 * either direction
36 */ 36 */
37 37
38 /*----------------------------------------------------------------*/ 38 /*----------------------------------------------------------------*/
39 39
40 static size_t bitset_size_in_bytes(unsigned nr_entries) 40 static size_t bitset_size_in_bytes(unsigned nr_entries)
41 { 41 {
42 return sizeof(unsigned long) * dm_div_up(nr_entries, BITS_PER_LONG); 42 return sizeof(unsigned long) * dm_div_up(nr_entries, BITS_PER_LONG);
43 } 43 }
44 44
45 static unsigned long *alloc_bitset(unsigned nr_entries) 45 static unsigned long *alloc_bitset(unsigned nr_entries)
46 { 46 {
47 size_t s = bitset_size_in_bytes(nr_entries); 47 size_t s = bitset_size_in_bytes(nr_entries);
48 return vzalloc(s); 48 return vzalloc(s);
49 } 49 }
50 50
51 static void clear_bitset(void *bitset, unsigned nr_entries) 51 static void clear_bitset(void *bitset, unsigned nr_entries)
52 { 52 {
53 size_t s = bitset_size_in_bytes(nr_entries); 53 size_t s = bitset_size_in_bytes(nr_entries);
54 memset(bitset, 0, s); 54 memset(bitset, 0, s);
55 } 55 }
56 56
57 static void free_bitset(unsigned long *bits) 57 static void free_bitset(unsigned long *bits)
58 { 58 {
59 vfree(bits); 59 vfree(bits);
60 } 60 }
61 61
62 /*----------------------------------------------------------------*/ 62 /*----------------------------------------------------------------*/
63 63
64 #define PRISON_CELLS 1024 64 #define PRISON_CELLS 1024
65 #define MIGRATION_POOL_SIZE 128 65 #define MIGRATION_POOL_SIZE 128
66 #define COMMIT_PERIOD HZ 66 #define COMMIT_PERIOD HZ
67 #define MIGRATION_COUNT_WINDOW 10 67 #define MIGRATION_COUNT_WINDOW 10
68 68
69 /* 69 /*
70 * The block size of the device holding cache data must be >= 32KB 70 * The block size of the device holding cache data must be >= 32KB
71 */ 71 */
72 #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (32 * 1024 >> SECTOR_SHIFT) 72 #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (32 * 1024 >> SECTOR_SHIFT)
73 73
74 /* 74 /*
75 * FIXME: the cache is read/write for the time being. 75 * FIXME: the cache is read/write for the time being.
76 */ 76 */
77 enum cache_mode { 77 enum cache_mode {
78 CM_WRITE, /* metadata may be changed */ 78 CM_WRITE, /* metadata may be changed */
79 CM_READ_ONLY, /* metadata may not be changed */ 79 CM_READ_ONLY, /* metadata may not be changed */
80 }; 80 };
81 81
82 struct cache_features { 82 struct cache_features {
83 enum cache_mode mode; 83 enum cache_mode mode;
84 bool write_through:1; 84 bool write_through:1;
85 }; 85 };
86 86
87 struct cache_stats { 87 struct cache_stats {
88 atomic_t read_hit; 88 atomic_t read_hit;
89 atomic_t read_miss; 89 atomic_t read_miss;
90 atomic_t write_hit; 90 atomic_t write_hit;
91 atomic_t write_miss; 91 atomic_t write_miss;
92 atomic_t demotion; 92 atomic_t demotion;
93 atomic_t promotion; 93 atomic_t promotion;
94 atomic_t copies_avoided; 94 atomic_t copies_avoided;
95 atomic_t cache_cell_clash; 95 atomic_t cache_cell_clash;
96 atomic_t commit_count; 96 atomic_t commit_count;
97 atomic_t discard_count; 97 atomic_t discard_count;
98 }; 98 };
99 99
100 struct cache { 100 struct cache {
101 struct dm_target *ti; 101 struct dm_target *ti;
102 struct dm_target_callbacks callbacks; 102 struct dm_target_callbacks callbacks;
103 103
104 /* 104 /*
105 * Metadata is written to this device. 105 * Metadata is written to this device.
106 */ 106 */
107 struct dm_dev *metadata_dev; 107 struct dm_dev *metadata_dev;
108 108
109 /* 109 /*
110 * The slower of the two data devices. Typically a spindle. 110 * The slower of the two data devices. Typically a spindle.
111 */ 111 */
112 struct dm_dev *origin_dev; 112 struct dm_dev *origin_dev;
113 113
114 /* 114 /*
115 * The faster of the two data devices. Typically an SSD. 115 * The faster of the two data devices. Typically an SSD.
116 */ 116 */
117 struct dm_dev *cache_dev; 117 struct dm_dev *cache_dev;
118 118
119 /* 119 /*
120 * Cache features such as write-through. 120 * Cache features such as write-through.
121 */ 121 */
122 struct cache_features features; 122 struct cache_features features;
123 123
124 /* 124 /*
125 * Size of the origin device in _complete_ blocks and native sectors. 125 * Size of the origin device in _complete_ blocks and native sectors.
126 */ 126 */
127 dm_oblock_t origin_blocks; 127 dm_oblock_t origin_blocks;
128 sector_t origin_sectors; 128 sector_t origin_sectors;
129 129
130 /* 130 /*
131 * Size of the cache device in blocks. 131 * Size of the cache device in blocks.
132 */ 132 */
133 dm_cblock_t cache_size; 133 dm_cblock_t cache_size;
134 134
135 /* 135 /*
136 * Fields for converting from sectors to blocks. 136 * Fields for converting from sectors to blocks.
137 */ 137 */
138 uint32_t sectors_per_block; 138 uint32_t sectors_per_block;
139 int sectors_per_block_shift; 139 int sectors_per_block_shift;
140 140
141 struct dm_cache_metadata *cmd; 141 struct dm_cache_metadata *cmd;
142 142
143 spinlock_t lock; 143 spinlock_t lock;
144 struct bio_list deferred_bios; 144 struct bio_list deferred_bios;
145 struct bio_list deferred_flush_bios; 145 struct bio_list deferred_flush_bios;
146 struct bio_list deferred_writethrough_bios; 146 struct bio_list deferred_writethrough_bios;
147 struct list_head quiesced_migrations; 147 struct list_head quiesced_migrations;
148 struct list_head completed_migrations; 148 struct list_head completed_migrations;
149 struct list_head need_commit_migrations; 149 struct list_head need_commit_migrations;
150 sector_t migration_threshold; 150 sector_t migration_threshold;
151 atomic_t nr_migrations; 151 atomic_t nr_migrations;
152 wait_queue_head_t migration_wait; 152 wait_queue_head_t migration_wait;
153 153
154 /* 154 /*
155 * cache_size entries, dirty if set 155 * cache_size entries, dirty if set
156 */ 156 */
157 dm_cblock_t nr_dirty; 157 dm_cblock_t nr_dirty;
158 unsigned long *dirty_bitset; 158 unsigned long *dirty_bitset;
159 159
160 /* 160 /*
161 * origin_blocks entries, discarded if set. 161 * origin_blocks entries, discarded if set.
162 */ 162 */
163 uint32_t discard_block_size; /* a power of 2 times sectors per block */ 163 uint32_t discard_block_size; /* a power of 2 times sectors per block */
164 dm_dblock_t discard_nr_blocks; 164 dm_dblock_t discard_nr_blocks;
165 unsigned long *discard_bitset; 165 unsigned long *discard_bitset;
166 166
167 struct dm_kcopyd_client *copier; 167 struct dm_kcopyd_client *copier;
168 struct workqueue_struct *wq; 168 struct workqueue_struct *wq;
169 struct work_struct worker; 169 struct work_struct worker;
170 170
171 struct delayed_work waker; 171 struct delayed_work waker;
172 unsigned long last_commit_jiffies; 172 unsigned long last_commit_jiffies;
173 173
174 struct dm_bio_prison *prison; 174 struct dm_bio_prison *prison;
175 struct dm_deferred_set *all_io_ds; 175 struct dm_deferred_set *all_io_ds;
176 176
177 mempool_t *migration_pool; 177 mempool_t *migration_pool;
178 struct dm_cache_migration *next_migration; 178 struct dm_cache_migration *next_migration;
179 179
180 struct dm_cache_policy *policy; 180 struct dm_cache_policy *policy;
181 unsigned policy_nr_args; 181 unsigned policy_nr_args;
182 182
183 bool need_tick_bio:1; 183 bool need_tick_bio:1;
184 bool sized:1; 184 bool sized:1;
185 bool quiescing:1; 185 bool quiescing:1;
186 bool commit_requested:1; 186 bool commit_requested:1;
187 bool loaded_mappings:1; 187 bool loaded_mappings:1;
188 bool loaded_discards:1; 188 bool loaded_discards:1;
189 189
190 struct cache_stats stats; 190 struct cache_stats stats;
191 191
192 /* 192 /*
193 * Rather than reconstructing the table line for the status we just 193 * Rather than reconstructing the table line for the status we just
194 * save it and regurgitate. 194 * save it and regurgitate.
195 */ 195 */
196 unsigned nr_ctr_args; 196 unsigned nr_ctr_args;
197 const char **ctr_args; 197 const char **ctr_args;
198 }; 198 };
199 199
200 struct per_bio_data { 200 struct per_bio_data {
201 bool tick:1; 201 bool tick:1;
202 unsigned req_nr:2; 202 unsigned req_nr:2;
203 struct dm_deferred_entry *all_io_entry; 203 struct dm_deferred_entry *all_io_entry;
204 204
205 /* 205 /*
206 * writethrough fields. These MUST remain at the end of this 206 * writethrough fields. These MUST remain at the end of this
207 * structure and the 'cache' member must be the first as it 207 * structure and the 'cache' member must be the first as it
208 * is used to determine the offsetof the writethrough fields. 208 * is used to determine the offsetof the writethrough fields.
209 */ 209 */
210 struct cache *cache; 210 struct cache *cache;
211 dm_cblock_t cblock; 211 dm_cblock_t cblock;
212 bio_end_io_t *saved_bi_end_io; 212 bio_end_io_t *saved_bi_end_io;
213 struct dm_bio_details bio_details; 213 struct dm_bio_details bio_details;
214 }; 214 };
215 215
216 struct dm_cache_migration { 216 struct dm_cache_migration {
217 struct list_head list; 217 struct list_head list;
218 struct cache *cache; 218 struct cache *cache;
219 219
220 unsigned long start_jiffies; 220 unsigned long start_jiffies;
221 dm_oblock_t old_oblock; 221 dm_oblock_t old_oblock;
222 dm_oblock_t new_oblock; 222 dm_oblock_t new_oblock;
223 dm_cblock_t cblock; 223 dm_cblock_t cblock;
224 224
225 bool err:1; 225 bool err:1;
226 bool writeback:1; 226 bool writeback:1;
227 bool demote:1; 227 bool demote:1;
228 bool promote:1; 228 bool promote:1;
229 229
230 struct dm_bio_prison_cell *old_ocell; 230 struct dm_bio_prison_cell *old_ocell;
231 struct dm_bio_prison_cell *new_ocell; 231 struct dm_bio_prison_cell *new_ocell;
232 }; 232 };
233 233
234 /* 234 /*
235 * Processing a bio in the worker thread may require these memory 235 * Processing a bio in the worker thread may require these memory
236 * allocations. We prealloc to avoid deadlocks (the same worker thread 236 * allocations. We prealloc to avoid deadlocks (the same worker thread
237 * frees them back to the mempool). 237 * frees them back to the mempool).
238 */ 238 */
239 struct prealloc { 239 struct prealloc {
240 struct dm_cache_migration *mg; 240 struct dm_cache_migration *mg;
241 struct dm_bio_prison_cell *cell1; 241 struct dm_bio_prison_cell *cell1;
242 struct dm_bio_prison_cell *cell2; 242 struct dm_bio_prison_cell *cell2;
243 }; 243 };
244 244
245 static void wake_worker(struct cache *cache) 245 static void wake_worker(struct cache *cache)
246 { 246 {
247 queue_work(cache->wq, &cache->worker); 247 queue_work(cache->wq, &cache->worker);
248 } 248 }
249 249
250 /*----------------------------------------------------------------*/ 250 /*----------------------------------------------------------------*/
251 251
252 static struct dm_bio_prison_cell *alloc_prison_cell(struct cache *cache) 252 static struct dm_bio_prison_cell *alloc_prison_cell(struct cache *cache)
253 { 253 {
254 /* FIXME: change to use a local slab. */ 254 /* FIXME: change to use a local slab. */
255 return dm_bio_prison_alloc_cell(cache->prison, GFP_NOWAIT); 255 return dm_bio_prison_alloc_cell(cache->prison, GFP_NOWAIT);
256 } 256 }
257 257
258 static void free_prison_cell(struct cache *cache, struct dm_bio_prison_cell *cell) 258 static void free_prison_cell(struct cache *cache, struct dm_bio_prison_cell *cell)
259 { 259 {
260 dm_bio_prison_free_cell(cache->prison, cell); 260 dm_bio_prison_free_cell(cache->prison, cell);
261 } 261 }
262 262
263 static int prealloc_data_structs(struct cache *cache, struct prealloc *p) 263 static int prealloc_data_structs(struct cache *cache, struct prealloc *p)
264 { 264 {
265 if (!p->mg) { 265 if (!p->mg) {
266 p->mg = mempool_alloc(cache->migration_pool, GFP_NOWAIT); 266 p->mg = mempool_alloc(cache->migration_pool, GFP_NOWAIT);
267 if (!p->mg) 267 if (!p->mg)
268 return -ENOMEM; 268 return -ENOMEM;
269 } 269 }
270 270
271 if (!p->cell1) { 271 if (!p->cell1) {
272 p->cell1 = alloc_prison_cell(cache); 272 p->cell1 = alloc_prison_cell(cache);
273 if (!p->cell1) 273 if (!p->cell1)
274 return -ENOMEM; 274 return -ENOMEM;
275 } 275 }
276 276
277 if (!p->cell2) { 277 if (!p->cell2) {
278 p->cell2 = alloc_prison_cell(cache); 278 p->cell2 = alloc_prison_cell(cache);
279 if (!p->cell2) 279 if (!p->cell2)
280 return -ENOMEM; 280 return -ENOMEM;
281 } 281 }
282 282
283 return 0; 283 return 0;
284 } 284 }
285 285
286 static void prealloc_free_structs(struct cache *cache, struct prealloc *p) 286 static void prealloc_free_structs(struct cache *cache, struct prealloc *p)
287 { 287 {
288 if (p->cell2) 288 if (p->cell2)
289 free_prison_cell(cache, p->cell2); 289 free_prison_cell(cache, p->cell2);
290 290
291 if (p->cell1) 291 if (p->cell1)
292 free_prison_cell(cache, p->cell1); 292 free_prison_cell(cache, p->cell1);
293 293
294 if (p->mg) 294 if (p->mg)
295 mempool_free(p->mg, cache->migration_pool); 295 mempool_free(p->mg, cache->migration_pool);
296 } 296 }
297 297
298 static struct dm_cache_migration *prealloc_get_migration(struct prealloc *p) 298 static struct dm_cache_migration *prealloc_get_migration(struct prealloc *p)
299 { 299 {
300 struct dm_cache_migration *mg = p->mg; 300 struct dm_cache_migration *mg = p->mg;
301 301
302 BUG_ON(!mg); 302 BUG_ON(!mg);
303 p->mg = NULL; 303 p->mg = NULL;
304 304
305 return mg; 305 return mg;
306 } 306 }
307 307
308 /* 308 /*
309 * You must have a cell within the prealloc struct to return. If not this 309 * You must have a cell within the prealloc struct to return. If not this
310 * function will BUG() rather than returning NULL. 310 * function will BUG() rather than returning NULL.
311 */ 311 */
312 static struct dm_bio_prison_cell *prealloc_get_cell(struct prealloc *p) 312 static struct dm_bio_prison_cell *prealloc_get_cell(struct prealloc *p)
313 { 313 {
314 struct dm_bio_prison_cell *r = NULL; 314 struct dm_bio_prison_cell *r = NULL;
315 315
316 if (p->cell1) { 316 if (p->cell1) {
317 r = p->cell1; 317 r = p->cell1;
318 p->cell1 = NULL; 318 p->cell1 = NULL;
319 319
320 } else if (p->cell2) { 320 } else if (p->cell2) {
321 r = p->cell2; 321 r = p->cell2;
322 p->cell2 = NULL; 322 p->cell2 = NULL;
323 } else 323 } else
324 BUG(); 324 BUG();
325 325
326 return r; 326 return r;
327 } 327 }
328 328
329 /* 329 /*
330 * You can't have more than two cells in a prealloc struct. BUG() will be 330 * You can't have more than two cells in a prealloc struct. BUG() will be
331 * called if you try and overfill. 331 * called if you try and overfill.
332 */ 332 */
333 static void prealloc_put_cell(struct prealloc *p, struct dm_bio_prison_cell *cell) 333 static void prealloc_put_cell(struct prealloc *p, struct dm_bio_prison_cell *cell)
334 { 334 {
335 if (!p->cell2) 335 if (!p->cell2)
336 p->cell2 = cell; 336 p->cell2 = cell;
337 337
338 else if (!p->cell1) 338 else if (!p->cell1)
339 p->cell1 = cell; 339 p->cell1 = cell;
340 340
341 else 341 else
342 BUG(); 342 BUG();
343 } 343 }
344 344
345 /*----------------------------------------------------------------*/ 345 /*----------------------------------------------------------------*/
346 346
347 static void build_key(dm_oblock_t oblock, struct dm_cell_key *key) 347 static void build_key(dm_oblock_t oblock, struct dm_cell_key *key)
348 { 348 {
349 key->virtual = 0; 349 key->virtual = 0;
350 key->dev = 0; 350 key->dev = 0;
351 key->block = from_oblock(oblock); 351 key->block = from_oblock(oblock);
352 } 352 }
353 353
354 /* 354 /*
355 * The caller hands in a preallocated cell, and a free function for it. 355 * The caller hands in a preallocated cell, and a free function for it.
356 * The cell will be freed if there's an error, or if it wasn't used because 356 * The cell will be freed if there's an error, or if it wasn't used because
357 * a cell with that key already exists. 357 * a cell with that key already exists.
358 */ 358 */
359 typedef void (*cell_free_fn)(void *context, struct dm_bio_prison_cell *cell); 359 typedef void (*cell_free_fn)(void *context, struct dm_bio_prison_cell *cell);
360 360
361 static int bio_detain(struct cache *cache, dm_oblock_t oblock, 361 static int bio_detain(struct cache *cache, dm_oblock_t oblock,
362 struct bio *bio, struct dm_bio_prison_cell *cell_prealloc, 362 struct bio *bio, struct dm_bio_prison_cell *cell_prealloc,
363 cell_free_fn free_fn, void *free_context, 363 cell_free_fn free_fn, void *free_context,
364 struct dm_bio_prison_cell **cell_result) 364 struct dm_bio_prison_cell **cell_result)
365 { 365 {
366 int r; 366 int r;
367 struct dm_cell_key key; 367 struct dm_cell_key key;
368 368
369 build_key(oblock, &key); 369 build_key(oblock, &key);
370 r = dm_bio_detain(cache->prison, &key, bio, cell_prealloc, cell_result); 370 r = dm_bio_detain(cache->prison, &key, bio, cell_prealloc, cell_result);
371 if (r) 371 if (r)
372 free_fn(free_context, cell_prealloc); 372 free_fn(free_context, cell_prealloc);
373 373
374 return r; 374 return r;
375 } 375 }
376 376
377 static int get_cell(struct cache *cache, 377 static int get_cell(struct cache *cache,
378 dm_oblock_t oblock, 378 dm_oblock_t oblock,
379 struct prealloc *structs, 379 struct prealloc *structs,
380 struct dm_bio_prison_cell **cell_result) 380 struct dm_bio_prison_cell **cell_result)
381 { 381 {
382 int r; 382 int r;
383 struct dm_cell_key key; 383 struct dm_cell_key key;
384 struct dm_bio_prison_cell *cell_prealloc; 384 struct dm_bio_prison_cell *cell_prealloc;
385 385
386 cell_prealloc = prealloc_get_cell(structs); 386 cell_prealloc = prealloc_get_cell(structs);
387 387
388 build_key(oblock, &key); 388 build_key(oblock, &key);
389 r = dm_get_cell(cache->prison, &key, cell_prealloc, cell_result); 389 r = dm_get_cell(cache->prison, &key, cell_prealloc, cell_result);
390 if (r) 390 if (r)
391 prealloc_put_cell(structs, cell_prealloc); 391 prealloc_put_cell(structs, cell_prealloc);
392 392
393 return r; 393 return r;
394 } 394 }
395 395
396 /*----------------------------------------------------------------*/ 396 /*----------------------------------------------------------------*/
397 397
398 static bool is_dirty(struct cache *cache, dm_cblock_t b) 398 static bool is_dirty(struct cache *cache, dm_cblock_t b)
399 { 399 {
400 return test_bit(from_cblock(b), cache->dirty_bitset); 400 return test_bit(from_cblock(b), cache->dirty_bitset);
401 } 401 }
402 402
403 static void set_dirty(struct cache *cache, dm_oblock_t oblock, dm_cblock_t cblock) 403 static void set_dirty(struct cache *cache, dm_oblock_t oblock, dm_cblock_t cblock)
404 { 404 {
405 if (!test_and_set_bit(from_cblock(cblock), cache->dirty_bitset)) { 405 if (!test_and_set_bit(from_cblock(cblock), cache->dirty_bitset)) {
406 cache->nr_dirty = to_cblock(from_cblock(cache->nr_dirty) + 1); 406 cache->nr_dirty = to_cblock(from_cblock(cache->nr_dirty) + 1);
407 policy_set_dirty(cache->policy, oblock); 407 policy_set_dirty(cache->policy, oblock);
408 } 408 }
409 } 409 }
410 410
411 static void clear_dirty(struct cache *cache, dm_oblock_t oblock, dm_cblock_t cblock) 411 static void clear_dirty(struct cache *cache, dm_oblock_t oblock, dm_cblock_t cblock)
412 { 412 {
413 if (test_and_clear_bit(from_cblock(cblock), cache->dirty_bitset)) { 413 if (test_and_clear_bit(from_cblock(cblock), cache->dirty_bitset)) {
414 policy_clear_dirty(cache->policy, oblock); 414 policy_clear_dirty(cache->policy, oblock);
415 cache->nr_dirty = to_cblock(from_cblock(cache->nr_dirty) - 1); 415 cache->nr_dirty = to_cblock(from_cblock(cache->nr_dirty) - 1);
416 if (!from_cblock(cache->nr_dirty)) 416 if (!from_cblock(cache->nr_dirty))
417 dm_table_event(cache->ti->table); 417 dm_table_event(cache->ti->table);
418 } 418 }
419 } 419 }
420 420
421 /*----------------------------------------------------------------*/ 421 /*----------------------------------------------------------------*/
422 static bool block_size_is_power_of_two(struct cache *cache) 422 static bool block_size_is_power_of_two(struct cache *cache)
423 { 423 {
424 return cache->sectors_per_block_shift >= 0; 424 return cache->sectors_per_block_shift >= 0;
425 } 425 }
426 426
427 static dm_block_t block_div(dm_block_t b, uint32_t n) 427 static dm_block_t block_div(dm_block_t b, uint32_t n)
428 { 428 {
429 do_div(b, n); 429 do_div(b, n);
430 430
431 return b; 431 return b;
432 } 432 }
433 433
434 static dm_dblock_t oblock_to_dblock(struct cache *cache, dm_oblock_t oblock) 434 static dm_dblock_t oblock_to_dblock(struct cache *cache, dm_oblock_t oblock)
435 { 435 {
436 uint32_t discard_blocks = cache->discard_block_size; 436 uint32_t discard_blocks = cache->discard_block_size;
437 dm_block_t b = from_oblock(oblock); 437 dm_block_t b = from_oblock(oblock);
438 438
439 if (!block_size_is_power_of_two(cache)) 439 if (!block_size_is_power_of_two(cache))
440 discard_blocks = discard_blocks / cache->sectors_per_block; 440 discard_blocks = discard_blocks / cache->sectors_per_block;
441 else 441 else
442 discard_blocks >>= cache->sectors_per_block_shift; 442 discard_blocks >>= cache->sectors_per_block_shift;
443 443
444 b = block_div(b, discard_blocks); 444 b = block_div(b, discard_blocks);
445 445
446 return to_dblock(b); 446 return to_dblock(b);
447 } 447 }
448 448
449 static void set_discard(struct cache *cache, dm_dblock_t b) 449 static void set_discard(struct cache *cache, dm_dblock_t b)
450 { 450 {
451 unsigned long flags; 451 unsigned long flags;
452 452
453 atomic_inc(&cache->stats.discard_count); 453 atomic_inc(&cache->stats.discard_count);
454 454
455 spin_lock_irqsave(&cache->lock, flags); 455 spin_lock_irqsave(&cache->lock, flags);
456 set_bit(from_dblock(b), cache->discard_bitset); 456 set_bit(from_dblock(b), cache->discard_bitset);
457 spin_unlock_irqrestore(&cache->lock, flags); 457 spin_unlock_irqrestore(&cache->lock, flags);
458 } 458 }
459 459
460 static void clear_discard(struct cache *cache, dm_dblock_t b) 460 static void clear_discard(struct cache *cache, dm_dblock_t b)
461 { 461 {
462 unsigned long flags; 462 unsigned long flags;
463 463
464 spin_lock_irqsave(&cache->lock, flags); 464 spin_lock_irqsave(&cache->lock, flags);
465 clear_bit(from_dblock(b), cache->discard_bitset); 465 clear_bit(from_dblock(b), cache->discard_bitset);
466 spin_unlock_irqrestore(&cache->lock, flags); 466 spin_unlock_irqrestore(&cache->lock, flags);
467 } 467 }
468 468
469 static bool is_discarded(struct cache *cache, dm_dblock_t b) 469 static bool is_discarded(struct cache *cache, dm_dblock_t b)
470 { 470 {
471 int r; 471 int r;
472 unsigned long flags; 472 unsigned long flags;
473 473
474 spin_lock_irqsave(&cache->lock, flags); 474 spin_lock_irqsave(&cache->lock, flags);
475 r = test_bit(from_dblock(b), cache->discard_bitset); 475 r = test_bit(from_dblock(b), cache->discard_bitset);
476 spin_unlock_irqrestore(&cache->lock, flags); 476 spin_unlock_irqrestore(&cache->lock, flags);
477 477
478 return r; 478 return r;
479 } 479 }
480 480
481 static bool is_discarded_oblock(struct cache *cache, dm_oblock_t b) 481 static bool is_discarded_oblock(struct cache *cache, dm_oblock_t b)
482 { 482 {
483 int r; 483 int r;
484 unsigned long flags; 484 unsigned long flags;
485 485
486 spin_lock_irqsave(&cache->lock, flags); 486 spin_lock_irqsave(&cache->lock, flags);
487 r = test_bit(from_dblock(oblock_to_dblock(cache, b)), 487 r = test_bit(from_dblock(oblock_to_dblock(cache, b)),
488 cache->discard_bitset); 488 cache->discard_bitset);
489 spin_unlock_irqrestore(&cache->lock, flags); 489 spin_unlock_irqrestore(&cache->lock, flags);
490 490
491 return r; 491 return r;
492 } 492 }
493 493
494 /*----------------------------------------------------------------*/ 494 /*----------------------------------------------------------------*/
495 495
496 static void load_stats(struct cache *cache) 496 static void load_stats(struct cache *cache)
497 { 497 {
498 struct dm_cache_statistics stats; 498 struct dm_cache_statistics stats;
499 499
500 dm_cache_metadata_get_stats(cache->cmd, &stats); 500 dm_cache_metadata_get_stats(cache->cmd, &stats);
501 atomic_set(&cache->stats.read_hit, stats.read_hits); 501 atomic_set(&cache->stats.read_hit, stats.read_hits);
502 atomic_set(&cache->stats.read_miss, stats.read_misses); 502 atomic_set(&cache->stats.read_miss, stats.read_misses);
503 atomic_set(&cache->stats.write_hit, stats.write_hits); 503 atomic_set(&cache->stats.write_hit, stats.write_hits);
504 atomic_set(&cache->stats.write_miss, stats.write_misses); 504 atomic_set(&cache->stats.write_miss, stats.write_misses);
505 } 505 }
506 506
507 static void save_stats(struct cache *cache) 507 static void save_stats(struct cache *cache)
508 { 508 {
509 struct dm_cache_statistics stats; 509 struct dm_cache_statistics stats;
510 510
511 stats.read_hits = atomic_read(&cache->stats.read_hit); 511 stats.read_hits = atomic_read(&cache->stats.read_hit);
512 stats.read_misses = atomic_read(&cache->stats.read_miss); 512 stats.read_misses = atomic_read(&cache->stats.read_miss);
513 stats.write_hits = atomic_read(&cache->stats.write_hit); 513 stats.write_hits = atomic_read(&cache->stats.write_hit);
514 stats.write_misses = atomic_read(&cache->stats.write_miss); 514 stats.write_misses = atomic_read(&cache->stats.write_miss);
515 515
516 dm_cache_metadata_set_stats(cache->cmd, &stats); 516 dm_cache_metadata_set_stats(cache->cmd, &stats);
517 } 517 }
518 518
519 /*---------------------------------------------------------------- 519 /*----------------------------------------------------------------
520 * Per bio data 520 * Per bio data
521 *--------------------------------------------------------------*/ 521 *--------------------------------------------------------------*/
522 522
523 /* 523 /*
524 * If using writeback, leave out struct per_bio_data's writethrough fields. 524 * If using writeback, leave out struct per_bio_data's writethrough fields.
525 */ 525 */
526 #define PB_DATA_SIZE_WB (offsetof(struct per_bio_data, cache)) 526 #define PB_DATA_SIZE_WB (offsetof(struct per_bio_data, cache))
527 #define PB_DATA_SIZE_WT (sizeof(struct per_bio_data)) 527 #define PB_DATA_SIZE_WT (sizeof(struct per_bio_data))
528 528
529 static size_t get_per_bio_data_size(struct cache *cache) 529 static size_t get_per_bio_data_size(struct cache *cache)
530 { 530 {
531 return cache->features.write_through ? PB_DATA_SIZE_WT : PB_DATA_SIZE_WB; 531 return cache->features.write_through ? PB_DATA_SIZE_WT : PB_DATA_SIZE_WB;
532 } 532 }
533 533
534 static struct per_bio_data *get_per_bio_data(struct bio *bio, size_t data_size) 534 static struct per_bio_data *get_per_bio_data(struct bio *bio, size_t data_size)
535 { 535 {
536 struct per_bio_data *pb = dm_per_bio_data(bio, data_size); 536 struct per_bio_data *pb = dm_per_bio_data(bio, data_size);
537 BUG_ON(!pb); 537 BUG_ON(!pb);
538 return pb; 538 return pb;
539 } 539 }
540 540
541 static struct per_bio_data *init_per_bio_data(struct bio *bio, size_t data_size) 541 static struct per_bio_data *init_per_bio_data(struct bio *bio, size_t data_size)
542 { 542 {
543 struct per_bio_data *pb = get_per_bio_data(bio, data_size); 543 struct per_bio_data *pb = get_per_bio_data(bio, data_size);
544 544
545 pb->tick = false; 545 pb->tick = false;
546 pb->req_nr = dm_bio_get_target_bio_nr(bio); 546 pb->req_nr = dm_bio_get_target_bio_nr(bio);
547 pb->all_io_entry = NULL; 547 pb->all_io_entry = NULL;
548 548
549 return pb; 549 return pb;
550 } 550 }
551 551
552 /*---------------------------------------------------------------- 552 /*----------------------------------------------------------------
553 * Remapping 553 * Remapping
554 *--------------------------------------------------------------*/ 554 *--------------------------------------------------------------*/
555 static void remap_to_origin(struct cache *cache, struct bio *bio) 555 static void remap_to_origin(struct cache *cache, struct bio *bio)
556 { 556 {
557 bio->bi_bdev = cache->origin_dev->bdev; 557 bio->bi_bdev = cache->origin_dev->bdev;
558 } 558 }
559 559
560 static void remap_to_cache(struct cache *cache, struct bio *bio, 560 static void remap_to_cache(struct cache *cache, struct bio *bio,
561 dm_cblock_t cblock) 561 dm_cblock_t cblock)
562 { 562 {
563 sector_t bi_sector = bio->bi_sector; 563 sector_t bi_sector = bio->bi_sector;
564 564
565 bio->bi_bdev = cache->cache_dev->bdev; 565 bio->bi_bdev = cache->cache_dev->bdev;
566 if (!block_size_is_power_of_two(cache)) 566 if (!block_size_is_power_of_two(cache))
567 bio->bi_sector = (from_cblock(cblock) * cache->sectors_per_block) + 567 bio->bi_sector = (from_cblock(cblock) * cache->sectors_per_block) +
568 sector_div(bi_sector, cache->sectors_per_block); 568 sector_div(bi_sector, cache->sectors_per_block);
569 else 569 else
570 bio->bi_sector = (from_cblock(cblock) << cache->sectors_per_block_shift) | 570 bio->bi_sector = (from_cblock(cblock) << cache->sectors_per_block_shift) |
571 (bi_sector & (cache->sectors_per_block - 1)); 571 (bi_sector & (cache->sectors_per_block - 1));
572 } 572 }
573 573
574 static void check_if_tick_bio_needed(struct cache *cache, struct bio *bio) 574 static void check_if_tick_bio_needed(struct cache *cache, struct bio *bio)
575 { 575 {
576 unsigned long flags; 576 unsigned long flags;
577 size_t pb_data_size = get_per_bio_data_size(cache); 577 size_t pb_data_size = get_per_bio_data_size(cache);
578 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); 578 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
579 579
580 spin_lock_irqsave(&cache->lock, flags); 580 spin_lock_irqsave(&cache->lock, flags);
581 if (cache->need_tick_bio && 581 if (cache->need_tick_bio &&
582 !(bio->bi_rw & (REQ_FUA | REQ_FLUSH | REQ_DISCARD))) { 582 !(bio->bi_rw & (REQ_FUA | REQ_FLUSH | REQ_DISCARD))) {
583 pb->tick = true; 583 pb->tick = true;
584 cache->need_tick_bio = false; 584 cache->need_tick_bio = false;
585 } 585 }
586 spin_unlock_irqrestore(&cache->lock, flags); 586 spin_unlock_irqrestore(&cache->lock, flags);
587 } 587 }
588 588
589 static void remap_to_origin_clear_discard(struct cache *cache, struct bio *bio, 589 static void remap_to_origin_clear_discard(struct cache *cache, struct bio *bio,
590 dm_oblock_t oblock) 590 dm_oblock_t oblock)
591 { 591 {
592 check_if_tick_bio_needed(cache, bio); 592 check_if_tick_bio_needed(cache, bio);
593 remap_to_origin(cache, bio); 593 remap_to_origin(cache, bio);
594 if (bio_data_dir(bio) == WRITE) 594 if (bio_data_dir(bio) == WRITE)
595 clear_discard(cache, oblock_to_dblock(cache, oblock)); 595 clear_discard(cache, oblock_to_dblock(cache, oblock));
596 } 596 }
597 597
598 static void remap_to_cache_dirty(struct cache *cache, struct bio *bio, 598 static void remap_to_cache_dirty(struct cache *cache, struct bio *bio,
599 dm_oblock_t oblock, dm_cblock_t cblock) 599 dm_oblock_t oblock, dm_cblock_t cblock)
600 { 600 {
601 remap_to_cache(cache, bio, cblock); 601 remap_to_cache(cache, bio, cblock);
602 if (bio_data_dir(bio) == WRITE) { 602 if (bio_data_dir(bio) == WRITE) {
603 set_dirty(cache, oblock, cblock); 603 set_dirty(cache, oblock, cblock);
604 clear_discard(cache, oblock_to_dblock(cache, oblock)); 604 clear_discard(cache, oblock_to_dblock(cache, oblock));
605 } 605 }
606 } 606 }
607 607
608 static dm_oblock_t get_bio_block(struct cache *cache, struct bio *bio) 608 static dm_oblock_t get_bio_block(struct cache *cache, struct bio *bio)
609 { 609 {
610 sector_t block_nr = bio->bi_sector; 610 sector_t block_nr = bio->bi_sector;
611 611
612 if (!block_size_is_power_of_two(cache)) 612 if (!block_size_is_power_of_two(cache))
613 (void) sector_div(block_nr, cache->sectors_per_block); 613 (void) sector_div(block_nr, cache->sectors_per_block);
614 else 614 else
615 block_nr >>= cache->sectors_per_block_shift; 615 block_nr >>= cache->sectors_per_block_shift;
616 616
617 return to_oblock(block_nr); 617 return to_oblock(block_nr);
618 } 618 }
619 619
620 static int bio_triggers_commit(struct cache *cache, struct bio *bio) 620 static int bio_triggers_commit(struct cache *cache, struct bio *bio)
621 { 621 {
622 return bio->bi_rw & (REQ_FLUSH | REQ_FUA); 622 return bio->bi_rw & (REQ_FLUSH | REQ_FUA);
623 } 623 }
624 624
625 static void issue(struct cache *cache, struct bio *bio) 625 static void issue(struct cache *cache, struct bio *bio)
626 { 626 {
627 unsigned long flags; 627 unsigned long flags;
628 628
629 if (!bio_triggers_commit(cache, bio)) { 629 if (!bio_triggers_commit(cache, bio)) {
630 generic_make_request(bio); 630 generic_make_request(bio);
631 return; 631 return;
632 } 632 }
633 633
634 /* 634 /*
635 * Batch together any bios that trigger commits and then issue a 635 * Batch together any bios that trigger commits and then issue a
636 * single commit for them in do_worker(). 636 * single commit for them in do_worker().
637 */ 637 */
638 spin_lock_irqsave(&cache->lock, flags); 638 spin_lock_irqsave(&cache->lock, flags);
639 cache->commit_requested = true; 639 cache->commit_requested = true;
640 bio_list_add(&cache->deferred_flush_bios, bio); 640 bio_list_add(&cache->deferred_flush_bios, bio);
641 spin_unlock_irqrestore(&cache->lock, flags); 641 spin_unlock_irqrestore(&cache->lock, flags);
642 } 642 }
643 643
644 static void defer_writethrough_bio(struct cache *cache, struct bio *bio) 644 static void defer_writethrough_bio(struct cache *cache, struct bio *bio)
645 { 645 {
646 unsigned long flags; 646 unsigned long flags;
647 647
648 spin_lock_irqsave(&cache->lock, flags); 648 spin_lock_irqsave(&cache->lock, flags);
649 bio_list_add(&cache->deferred_writethrough_bios, bio); 649 bio_list_add(&cache->deferred_writethrough_bios, bio);
650 spin_unlock_irqrestore(&cache->lock, flags); 650 spin_unlock_irqrestore(&cache->lock, flags);
651 651
652 wake_worker(cache); 652 wake_worker(cache);
653 } 653 }
654 654
655 static void writethrough_endio(struct bio *bio, int err) 655 static void writethrough_endio(struct bio *bio, int err)
656 { 656 {
657 struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT); 657 struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT);
658 bio->bi_end_io = pb->saved_bi_end_io; 658 bio->bi_end_io = pb->saved_bi_end_io;
659 659
660 if (err) { 660 if (err) {
661 bio_endio(bio, err); 661 bio_endio(bio, err);
662 return; 662 return;
663 } 663 }
664 664
665 dm_bio_restore(&pb->bio_details, bio); 665 dm_bio_restore(&pb->bio_details, bio);
666 remap_to_cache(pb->cache, bio, pb->cblock); 666 remap_to_cache(pb->cache, bio, pb->cblock);
667 667
668 /* 668 /*
669 * We can't issue this bio directly, since we're in interrupt 669 * We can't issue this bio directly, since we're in interrupt
670 * context. So it get's put on a bio list for processing by the 670 * context. So it get's put on a bio list for processing by the
671 * worker thread. 671 * worker thread.
672 */ 672 */
673 defer_writethrough_bio(pb->cache, bio); 673 defer_writethrough_bio(pb->cache, bio);
674 } 674 }
675 675
676 /* 676 /*
677 * When running in writethrough mode we need to send writes to clean blocks 677 * When running in writethrough mode we need to send writes to clean blocks
678 * to both the cache and origin devices. In future we'd like to clone the 678 * to both the cache and origin devices. In future we'd like to clone the
679 * bio and send them in parallel, but for now we're doing them in 679 * bio and send them in parallel, but for now we're doing them in
680 * series as this is easier. 680 * series as this is easier.
681 */ 681 */
682 static void remap_to_origin_then_cache(struct cache *cache, struct bio *bio, 682 static void remap_to_origin_then_cache(struct cache *cache, struct bio *bio,
683 dm_oblock_t oblock, dm_cblock_t cblock) 683 dm_oblock_t oblock, dm_cblock_t cblock)
684 { 684 {
685 struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT); 685 struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT);
686 686
687 pb->cache = cache; 687 pb->cache = cache;
688 pb->cblock = cblock; 688 pb->cblock = cblock;
689 pb->saved_bi_end_io = bio->bi_end_io; 689 pb->saved_bi_end_io = bio->bi_end_io;
690 dm_bio_record(&pb->bio_details, bio); 690 dm_bio_record(&pb->bio_details, bio);
691 bio->bi_end_io = writethrough_endio; 691 bio->bi_end_io = writethrough_endio;
692 692
693 remap_to_origin_clear_discard(pb->cache, bio, oblock); 693 remap_to_origin_clear_discard(pb->cache, bio, oblock);
694 } 694 }
695 695
696 /*---------------------------------------------------------------- 696 /*----------------------------------------------------------------
697 * Migration processing 697 * Migration processing
698 * 698 *
699 * Migration covers moving data from the origin device to the cache, or 699 * Migration covers moving data from the origin device to the cache, or
700 * vice versa. 700 * vice versa.
701 *--------------------------------------------------------------*/ 701 *--------------------------------------------------------------*/
702 static void free_migration(struct dm_cache_migration *mg) 702 static void free_migration(struct dm_cache_migration *mg)
703 { 703 {
704 mempool_free(mg, mg->cache->migration_pool); 704 mempool_free(mg, mg->cache->migration_pool);
705 } 705 }
706 706
707 static void inc_nr_migrations(struct cache *cache) 707 static void inc_nr_migrations(struct cache *cache)
708 { 708 {
709 atomic_inc(&cache->nr_migrations); 709 atomic_inc(&cache->nr_migrations);
710 } 710 }
711 711
712 static void dec_nr_migrations(struct cache *cache) 712 static void dec_nr_migrations(struct cache *cache)
713 { 713 {
714 atomic_dec(&cache->nr_migrations); 714 atomic_dec(&cache->nr_migrations);
715 715
716 /* 716 /*
717 * Wake the worker in case we're suspending the target. 717 * Wake the worker in case we're suspending the target.
718 */ 718 */
719 wake_up(&cache->migration_wait); 719 wake_up(&cache->migration_wait);
720 } 720 }
721 721
722 static void __cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell, 722 static void __cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell,
723 bool holder) 723 bool holder)
724 { 724 {
725 (holder ? dm_cell_release : dm_cell_release_no_holder) 725 (holder ? dm_cell_release : dm_cell_release_no_holder)
726 (cache->prison, cell, &cache->deferred_bios); 726 (cache->prison, cell, &cache->deferred_bios);
727 free_prison_cell(cache, cell); 727 free_prison_cell(cache, cell);
728 } 728 }
729 729
730 static void cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell, 730 static void cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell,
731 bool holder) 731 bool holder)
732 { 732 {
733 unsigned long flags; 733 unsigned long flags;
734 734
735 spin_lock_irqsave(&cache->lock, flags); 735 spin_lock_irqsave(&cache->lock, flags);
736 __cell_defer(cache, cell, holder); 736 __cell_defer(cache, cell, holder);
737 spin_unlock_irqrestore(&cache->lock, flags); 737 spin_unlock_irqrestore(&cache->lock, flags);
738 738
739 wake_worker(cache); 739 wake_worker(cache);
740 } 740 }
741 741
742 static void cleanup_migration(struct dm_cache_migration *mg) 742 static void cleanup_migration(struct dm_cache_migration *mg)
743 { 743 {
744 dec_nr_migrations(mg->cache); 744 dec_nr_migrations(mg->cache);
745 free_migration(mg); 745 free_migration(mg);
746 } 746 }
747 747
748 static void migration_failure(struct dm_cache_migration *mg) 748 static void migration_failure(struct dm_cache_migration *mg)
749 { 749 {
750 struct cache *cache = mg->cache; 750 struct cache *cache = mg->cache;
751 751
752 if (mg->writeback) { 752 if (mg->writeback) {
753 DMWARN_LIMIT("writeback failed; couldn't copy block"); 753 DMWARN_LIMIT("writeback failed; couldn't copy block");
754 set_dirty(cache, mg->old_oblock, mg->cblock); 754 set_dirty(cache, mg->old_oblock, mg->cblock);
755 cell_defer(cache, mg->old_ocell, false); 755 cell_defer(cache, mg->old_ocell, false);
756 756
757 } else if (mg->demote) { 757 } else if (mg->demote) {
758 DMWARN_LIMIT("demotion failed; couldn't copy block"); 758 DMWARN_LIMIT("demotion failed; couldn't copy block");
759 policy_force_mapping(cache->policy, mg->new_oblock, mg->old_oblock); 759 policy_force_mapping(cache->policy, mg->new_oblock, mg->old_oblock);
760 760
761 cell_defer(cache, mg->old_ocell, mg->promote ? 0 : 1); 761 cell_defer(cache, mg->old_ocell, mg->promote ? 0 : 1);
762 if (mg->promote) 762 if (mg->promote)
763 cell_defer(cache, mg->new_ocell, 1); 763 cell_defer(cache, mg->new_ocell, 1);
764 } else { 764 } else {
765 DMWARN_LIMIT("promotion failed; couldn't copy block"); 765 DMWARN_LIMIT("promotion failed; couldn't copy block");
766 policy_remove_mapping(cache->policy, mg->new_oblock); 766 policy_remove_mapping(cache->policy, mg->new_oblock);
767 cell_defer(cache, mg->new_ocell, 1); 767 cell_defer(cache, mg->new_ocell, 1);
768 } 768 }
769 769
770 cleanup_migration(mg); 770 cleanup_migration(mg);
771 } 771 }
772 772
773 static void migration_success_pre_commit(struct dm_cache_migration *mg) 773 static void migration_success_pre_commit(struct dm_cache_migration *mg)
774 { 774 {
775 unsigned long flags; 775 unsigned long flags;
776 struct cache *cache = mg->cache; 776 struct cache *cache = mg->cache;
777 777
778 if (mg->writeback) { 778 if (mg->writeback) {
779 cell_defer(cache, mg->old_ocell, false); 779 cell_defer(cache, mg->old_ocell, false);
780 clear_dirty(cache, mg->old_oblock, mg->cblock); 780 clear_dirty(cache, mg->old_oblock, mg->cblock);
781 cleanup_migration(mg); 781 cleanup_migration(mg);
782 return; 782 return;
783 783
784 } else if (mg->demote) { 784 } else if (mg->demote) {
785 if (dm_cache_remove_mapping(cache->cmd, mg->cblock)) { 785 if (dm_cache_remove_mapping(cache->cmd, mg->cblock)) {
786 DMWARN_LIMIT("demotion failed; couldn't update on disk metadata"); 786 DMWARN_LIMIT("demotion failed; couldn't update on disk metadata");
787 policy_force_mapping(cache->policy, mg->new_oblock, 787 policy_force_mapping(cache->policy, mg->new_oblock,
788 mg->old_oblock); 788 mg->old_oblock);
789 if (mg->promote) 789 if (mg->promote)
790 cell_defer(cache, mg->new_ocell, true); 790 cell_defer(cache, mg->new_ocell, true);
791 cleanup_migration(mg); 791 cleanup_migration(mg);
792 return; 792 return;
793 } 793 }
794 } else { 794 } else {
795 if (dm_cache_insert_mapping(cache->cmd, mg->cblock, mg->new_oblock)) { 795 if (dm_cache_insert_mapping(cache->cmd, mg->cblock, mg->new_oblock)) {
796 DMWARN_LIMIT("promotion failed; couldn't update on disk metadata"); 796 DMWARN_LIMIT("promotion failed; couldn't update on disk metadata");
797 policy_remove_mapping(cache->policy, mg->new_oblock); 797 policy_remove_mapping(cache->policy, mg->new_oblock);
798 cleanup_migration(mg); 798 cleanup_migration(mg);
799 return; 799 return;
800 } 800 }
801 } 801 }
802 802
803 spin_lock_irqsave(&cache->lock, flags); 803 spin_lock_irqsave(&cache->lock, flags);
804 list_add_tail(&mg->list, &cache->need_commit_migrations); 804 list_add_tail(&mg->list, &cache->need_commit_migrations);
805 cache->commit_requested = true; 805 cache->commit_requested = true;
806 spin_unlock_irqrestore(&cache->lock, flags); 806 spin_unlock_irqrestore(&cache->lock, flags);
807 } 807 }
808 808
809 static void migration_success_post_commit(struct dm_cache_migration *mg) 809 static void migration_success_post_commit(struct dm_cache_migration *mg)
810 { 810 {
811 unsigned long flags; 811 unsigned long flags;
812 struct cache *cache = mg->cache; 812 struct cache *cache = mg->cache;
813 813
814 if (mg->writeback) { 814 if (mg->writeback) {
815 DMWARN("writeback unexpectedly triggered commit"); 815 DMWARN("writeback unexpectedly triggered commit");
816 return; 816 return;
817 817
818 } else if (mg->demote) { 818 } else if (mg->demote) {
819 cell_defer(cache, mg->old_ocell, mg->promote ? 0 : 1); 819 cell_defer(cache, mg->old_ocell, mg->promote ? 0 : 1);
820 820
821 if (mg->promote) { 821 if (mg->promote) {
822 mg->demote = false; 822 mg->demote = false;
823 823
824 spin_lock_irqsave(&cache->lock, flags); 824 spin_lock_irqsave(&cache->lock, flags);
825 list_add_tail(&mg->list, &cache->quiesced_migrations); 825 list_add_tail(&mg->list, &cache->quiesced_migrations);
826 spin_unlock_irqrestore(&cache->lock, flags); 826 spin_unlock_irqrestore(&cache->lock, flags);
827 827
828 } else 828 } else
829 cleanup_migration(mg); 829 cleanup_migration(mg);
830 830
831 } else { 831 } else {
832 cell_defer(cache, mg->new_ocell, true); 832 cell_defer(cache, mg->new_ocell, true);
833 clear_dirty(cache, mg->new_oblock, mg->cblock); 833 clear_dirty(cache, mg->new_oblock, mg->cblock);
834 cleanup_migration(mg); 834 cleanup_migration(mg);
835 } 835 }
836 } 836 }
837 837
838 static void copy_complete(int read_err, unsigned long write_err, void *context) 838 static void copy_complete(int read_err, unsigned long write_err, void *context)
839 { 839 {
840 unsigned long flags; 840 unsigned long flags;
841 struct dm_cache_migration *mg = (struct dm_cache_migration *) context; 841 struct dm_cache_migration *mg = (struct dm_cache_migration *) context;
842 struct cache *cache = mg->cache; 842 struct cache *cache = mg->cache;
843 843
844 if (read_err || write_err) 844 if (read_err || write_err)
845 mg->err = true; 845 mg->err = true;
846 846
847 spin_lock_irqsave(&cache->lock, flags); 847 spin_lock_irqsave(&cache->lock, flags);
848 list_add_tail(&mg->list, &cache->completed_migrations); 848 list_add_tail(&mg->list, &cache->completed_migrations);
849 spin_unlock_irqrestore(&cache->lock, flags); 849 spin_unlock_irqrestore(&cache->lock, flags);
850 850
851 wake_worker(cache); 851 wake_worker(cache);
852 } 852 }
853 853
854 static void issue_copy_real(struct dm_cache_migration *mg) 854 static void issue_copy_real(struct dm_cache_migration *mg)
855 { 855 {
856 int r; 856 int r;
857 struct dm_io_region o_region, c_region; 857 struct dm_io_region o_region, c_region;
858 struct cache *cache = mg->cache; 858 struct cache *cache = mg->cache;
859 859
860 o_region.bdev = cache->origin_dev->bdev; 860 o_region.bdev = cache->origin_dev->bdev;
861 o_region.count = cache->sectors_per_block; 861 o_region.count = cache->sectors_per_block;
862 862
863 c_region.bdev = cache->cache_dev->bdev; 863 c_region.bdev = cache->cache_dev->bdev;
864 c_region.sector = from_cblock(mg->cblock) * cache->sectors_per_block; 864 c_region.sector = from_cblock(mg->cblock) * cache->sectors_per_block;
865 c_region.count = cache->sectors_per_block; 865 c_region.count = cache->sectors_per_block;
866 866
867 if (mg->writeback || mg->demote) { 867 if (mg->writeback || mg->demote) {
868 /* demote */ 868 /* demote */
869 o_region.sector = from_oblock(mg->old_oblock) * cache->sectors_per_block; 869 o_region.sector = from_oblock(mg->old_oblock) * cache->sectors_per_block;
870 r = dm_kcopyd_copy(cache->copier, &c_region, 1, &o_region, 0, copy_complete, mg); 870 r = dm_kcopyd_copy(cache->copier, &c_region, 1, &o_region, 0, copy_complete, mg);
871 } else { 871 } else {
872 /* promote */ 872 /* promote */
873 o_region.sector = from_oblock(mg->new_oblock) * cache->sectors_per_block; 873 o_region.sector = from_oblock(mg->new_oblock) * cache->sectors_per_block;
874 r = dm_kcopyd_copy(cache->copier, &o_region, 1, &c_region, 0, copy_complete, mg); 874 r = dm_kcopyd_copy(cache->copier, &o_region, 1, &c_region, 0, copy_complete, mg);
875 } 875 }
876 876
877 if (r < 0) 877 if (r < 0)
878 migration_failure(mg); 878 migration_failure(mg);
879 } 879 }
880 880
881 static void avoid_copy(struct dm_cache_migration *mg) 881 static void avoid_copy(struct dm_cache_migration *mg)
882 { 882 {
883 atomic_inc(&mg->cache->stats.copies_avoided); 883 atomic_inc(&mg->cache->stats.copies_avoided);
884 migration_success_pre_commit(mg); 884 migration_success_pre_commit(mg);
885 } 885 }
886 886
887 static void issue_copy(struct dm_cache_migration *mg) 887 static void issue_copy(struct dm_cache_migration *mg)
888 { 888 {
889 bool avoid; 889 bool avoid;
890 struct cache *cache = mg->cache; 890 struct cache *cache = mg->cache;
891 891
892 if (mg->writeback || mg->demote) 892 if (mg->writeback || mg->demote)
893 avoid = !is_dirty(cache, mg->cblock) || 893 avoid = !is_dirty(cache, mg->cblock) ||
894 is_discarded_oblock(cache, mg->old_oblock); 894 is_discarded_oblock(cache, mg->old_oblock);
895 else 895 else
896 avoid = is_discarded_oblock(cache, mg->new_oblock); 896 avoid = is_discarded_oblock(cache, mg->new_oblock);
897 897
898 avoid ? avoid_copy(mg) : issue_copy_real(mg); 898 avoid ? avoid_copy(mg) : issue_copy_real(mg);
899 } 899 }
900 900
901 static void complete_migration(struct dm_cache_migration *mg) 901 static void complete_migration(struct dm_cache_migration *mg)
902 { 902 {
903 if (mg->err) 903 if (mg->err)
904 migration_failure(mg); 904 migration_failure(mg);
905 else 905 else
906 migration_success_pre_commit(mg); 906 migration_success_pre_commit(mg);
907 } 907 }
908 908
909 static void process_migrations(struct cache *cache, struct list_head *head, 909 static void process_migrations(struct cache *cache, struct list_head *head,
910 void (*fn)(struct dm_cache_migration *)) 910 void (*fn)(struct dm_cache_migration *))
911 { 911 {
912 unsigned long flags; 912 unsigned long flags;
913 struct list_head list; 913 struct list_head list;
914 struct dm_cache_migration *mg, *tmp; 914 struct dm_cache_migration *mg, *tmp;
915 915
916 INIT_LIST_HEAD(&list); 916 INIT_LIST_HEAD(&list);
917 spin_lock_irqsave(&cache->lock, flags); 917 spin_lock_irqsave(&cache->lock, flags);
918 list_splice_init(head, &list); 918 list_splice_init(head, &list);
919 spin_unlock_irqrestore(&cache->lock, flags); 919 spin_unlock_irqrestore(&cache->lock, flags);
920 920
921 list_for_each_entry_safe(mg, tmp, &list, list) 921 list_for_each_entry_safe(mg, tmp, &list, list)
922 fn(mg); 922 fn(mg);
923 } 923 }
924 924
925 static void __queue_quiesced_migration(struct dm_cache_migration *mg) 925 static void __queue_quiesced_migration(struct dm_cache_migration *mg)
926 { 926 {
927 list_add_tail(&mg->list, &mg->cache->quiesced_migrations); 927 list_add_tail(&mg->list, &mg->cache->quiesced_migrations);
928 } 928 }
929 929
930 static void queue_quiesced_migration(struct dm_cache_migration *mg) 930 static void queue_quiesced_migration(struct dm_cache_migration *mg)
931 { 931 {
932 unsigned long flags; 932 unsigned long flags;
933 struct cache *cache = mg->cache; 933 struct cache *cache = mg->cache;
934 934
935 spin_lock_irqsave(&cache->lock, flags); 935 spin_lock_irqsave(&cache->lock, flags);
936 __queue_quiesced_migration(mg); 936 __queue_quiesced_migration(mg);
937 spin_unlock_irqrestore(&cache->lock, flags); 937 spin_unlock_irqrestore(&cache->lock, flags);
938 938
939 wake_worker(cache); 939 wake_worker(cache);
940 } 940 }
941 941
942 static void queue_quiesced_migrations(struct cache *cache, struct list_head *work) 942 static void queue_quiesced_migrations(struct cache *cache, struct list_head *work)
943 { 943 {
944 unsigned long flags; 944 unsigned long flags;
945 struct dm_cache_migration *mg, *tmp; 945 struct dm_cache_migration *mg, *tmp;
946 946
947 spin_lock_irqsave(&cache->lock, flags); 947 spin_lock_irqsave(&cache->lock, flags);
948 list_for_each_entry_safe(mg, tmp, work, list) 948 list_for_each_entry_safe(mg, tmp, work, list)
949 __queue_quiesced_migration(mg); 949 __queue_quiesced_migration(mg);
950 spin_unlock_irqrestore(&cache->lock, flags); 950 spin_unlock_irqrestore(&cache->lock, flags);
951 951
952 wake_worker(cache); 952 wake_worker(cache);
953 } 953 }
954 954
955 static void check_for_quiesced_migrations(struct cache *cache, 955 static void check_for_quiesced_migrations(struct cache *cache,
956 struct per_bio_data *pb) 956 struct per_bio_data *pb)
957 { 957 {
958 struct list_head work; 958 struct list_head work;
959 959
960 if (!pb->all_io_entry) 960 if (!pb->all_io_entry)
961 return; 961 return;
962 962
963 INIT_LIST_HEAD(&work); 963 INIT_LIST_HEAD(&work);
964 if (pb->all_io_entry) 964 if (pb->all_io_entry)
965 dm_deferred_entry_dec(pb->all_io_entry, &work); 965 dm_deferred_entry_dec(pb->all_io_entry, &work);
966 966
967 if (!list_empty(&work)) 967 if (!list_empty(&work))
968 queue_quiesced_migrations(cache, &work); 968 queue_quiesced_migrations(cache, &work);
969 } 969 }
970 970
971 static void quiesce_migration(struct dm_cache_migration *mg) 971 static void quiesce_migration(struct dm_cache_migration *mg)
972 { 972 {
973 if (!dm_deferred_set_add_work(mg->cache->all_io_ds, &mg->list)) 973 if (!dm_deferred_set_add_work(mg->cache->all_io_ds, &mg->list))
974 queue_quiesced_migration(mg); 974 queue_quiesced_migration(mg);
975 } 975 }
976 976
977 static void promote(struct cache *cache, struct prealloc *structs, 977 static void promote(struct cache *cache, struct prealloc *structs,
978 dm_oblock_t oblock, dm_cblock_t cblock, 978 dm_oblock_t oblock, dm_cblock_t cblock,
979 struct dm_bio_prison_cell *cell) 979 struct dm_bio_prison_cell *cell)
980 { 980 {
981 struct dm_cache_migration *mg = prealloc_get_migration(structs); 981 struct dm_cache_migration *mg = prealloc_get_migration(structs);
982 982
983 mg->err = false; 983 mg->err = false;
984 mg->writeback = false; 984 mg->writeback = false;
985 mg->demote = false; 985 mg->demote = false;
986 mg->promote = true; 986 mg->promote = true;
987 mg->cache = cache; 987 mg->cache = cache;
988 mg->new_oblock = oblock; 988 mg->new_oblock = oblock;
989 mg->cblock = cblock; 989 mg->cblock = cblock;
990 mg->old_ocell = NULL; 990 mg->old_ocell = NULL;
991 mg->new_ocell = cell; 991 mg->new_ocell = cell;
992 mg->start_jiffies = jiffies; 992 mg->start_jiffies = jiffies;
993 993
994 inc_nr_migrations(cache); 994 inc_nr_migrations(cache);
995 quiesce_migration(mg); 995 quiesce_migration(mg);
996 } 996 }
997 997
998 static void writeback(struct cache *cache, struct prealloc *structs, 998 static void writeback(struct cache *cache, struct prealloc *structs,
999 dm_oblock_t oblock, dm_cblock_t cblock, 999 dm_oblock_t oblock, dm_cblock_t cblock,
1000 struct dm_bio_prison_cell *cell) 1000 struct dm_bio_prison_cell *cell)
1001 { 1001 {
1002 struct dm_cache_migration *mg = prealloc_get_migration(structs); 1002 struct dm_cache_migration *mg = prealloc_get_migration(structs);
1003 1003
1004 mg->err = false; 1004 mg->err = false;
1005 mg->writeback = true; 1005 mg->writeback = true;
1006 mg->demote = false; 1006 mg->demote = false;
1007 mg->promote = false; 1007 mg->promote = false;
1008 mg->cache = cache; 1008 mg->cache = cache;
1009 mg->old_oblock = oblock; 1009 mg->old_oblock = oblock;
1010 mg->cblock = cblock; 1010 mg->cblock = cblock;
1011 mg->old_ocell = cell; 1011 mg->old_ocell = cell;
1012 mg->new_ocell = NULL; 1012 mg->new_ocell = NULL;
1013 mg->start_jiffies = jiffies; 1013 mg->start_jiffies = jiffies;
1014 1014
1015 inc_nr_migrations(cache); 1015 inc_nr_migrations(cache);
1016 quiesce_migration(mg); 1016 quiesce_migration(mg);
1017 } 1017 }
1018 1018
1019 static void demote_then_promote(struct cache *cache, struct prealloc *structs, 1019 static void demote_then_promote(struct cache *cache, struct prealloc *structs,
1020 dm_oblock_t old_oblock, dm_oblock_t new_oblock, 1020 dm_oblock_t old_oblock, dm_oblock_t new_oblock,
1021 dm_cblock_t cblock, 1021 dm_cblock_t cblock,
1022 struct dm_bio_prison_cell *old_ocell, 1022 struct dm_bio_prison_cell *old_ocell,
1023 struct dm_bio_prison_cell *new_ocell) 1023 struct dm_bio_prison_cell *new_ocell)
1024 { 1024 {
1025 struct dm_cache_migration *mg = prealloc_get_migration(structs); 1025 struct dm_cache_migration *mg = prealloc_get_migration(structs);
1026 1026
1027 mg->err = false; 1027 mg->err = false;
1028 mg->writeback = false; 1028 mg->writeback = false;
1029 mg->demote = true; 1029 mg->demote = true;
1030 mg->promote = true; 1030 mg->promote = true;
1031 mg->cache = cache; 1031 mg->cache = cache;
1032 mg->old_oblock = old_oblock; 1032 mg->old_oblock = old_oblock;
1033 mg->new_oblock = new_oblock; 1033 mg->new_oblock = new_oblock;
1034 mg->cblock = cblock; 1034 mg->cblock = cblock;
1035 mg->old_ocell = old_ocell; 1035 mg->old_ocell = old_ocell;
1036 mg->new_ocell = new_ocell; 1036 mg->new_ocell = new_ocell;
1037 mg->start_jiffies = jiffies; 1037 mg->start_jiffies = jiffies;
1038 1038
1039 inc_nr_migrations(cache); 1039 inc_nr_migrations(cache);
1040 quiesce_migration(mg); 1040 quiesce_migration(mg);
1041 } 1041 }
1042 1042
1043 /*---------------------------------------------------------------- 1043 /*----------------------------------------------------------------
1044 * bio processing 1044 * bio processing
1045 *--------------------------------------------------------------*/ 1045 *--------------------------------------------------------------*/
1046 static void defer_bio(struct cache *cache, struct bio *bio) 1046 static void defer_bio(struct cache *cache, struct bio *bio)
1047 { 1047 {
1048 unsigned long flags; 1048 unsigned long flags;
1049 1049
1050 spin_lock_irqsave(&cache->lock, flags); 1050 spin_lock_irqsave(&cache->lock, flags);
1051 bio_list_add(&cache->deferred_bios, bio); 1051 bio_list_add(&cache->deferred_bios, bio);
1052 spin_unlock_irqrestore(&cache->lock, flags); 1052 spin_unlock_irqrestore(&cache->lock, flags);
1053 1053
1054 wake_worker(cache); 1054 wake_worker(cache);
1055 } 1055 }
1056 1056
1057 static void process_flush_bio(struct cache *cache, struct bio *bio) 1057 static void process_flush_bio(struct cache *cache, struct bio *bio)
1058 { 1058 {
1059 size_t pb_data_size = get_per_bio_data_size(cache); 1059 size_t pb_data_size = get_per_bio_data_size(cache);
1060 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); 1060 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
1061 1061
1062 BUG_ON(bio->bi_size); 1062 BUG_ON(bio->bi_size);
1063 if (!pb->req_nr) 1063 if (!pb->req_nr)
1064 remap_to_origin(cache, bio); 1064 remap_to_origin(cache, bio);
1065 else 1065 else
1066 remap_to_cache(cache, bio, 0); 1066 remap_to_cache(cache, bio, 0);
1067 1067
1068 issue(cache, bio); 1068 issue(cache, bio);
1069 } 1069 }
1070 1070
1071 /* 1071 /*
1072 * People generally discard large parts of a device, eg, the whole device 1072 * People generally discard large parts of a device, eg, the whole device
1073 * when formatting. Splitting these large discards up into cache block 1073 * when formatting. Splitting these large discards up into cache block
1074 * sized ios and then quiescing (always neccessary for discard) takes too 1074 * sized ios and then quiescing (always neccessary for discard) takes too
1075 * long. 1075 * long.
1076 * 1076 *
1077 * We keep it simple, and allow any size of discard to come in, and just 1077 * We keep it simple, and allow any size of discard to come in, and just
1078 * mark off blocks on the discard bitset. No passdown occurs! 1078 * mark off blocks on the discard bitset. No passdown occurs!
1079 * 1079 *
1080 * To implement passdown we need to change the bio_prison such that a cell 1080 * To implement passdown we need to change the bio_prison such that a cell
1081 * can have a key that spans many blocks. 1081 * can have a key that spans many blocks.
1082 */ 1082 */
1083 static void process_discard_bio(struct cache *cache, struct bio *bio) 1083 static void process_discard_bio(struct cache *cache, struct bio *bio)
1084 { 1084 {
1085 dm_block_t start_block = dm_sector_div_up(bio->bi_sector, 1085 dm_block_t start_block = dm_sector_div_up(bio->bi_sector,
1086 cache->discard_block_size); 1086 cache->discard_block_size);
1087 dm_block_t end_block = bio->bi_sector + bio_sectors(bio); 1087 dm_block_t end_block = bio->bi_sector + bio_sectors(bio);
1088 dm_block_t b; 1088 dm_block_t b;
1089 1089
1090 end_block = block_div(end_block, cache->discard_block_size); 1090 end_block = block_div(end_block, cache->discard_block_size);
1091 1091
1092 for (b = start_block; b < end_block; b++) 1092 for (b = start_block; b < end_block; b++)
1093 set_discard(cache, to_dblock(b)); 1093 set_discard(cache, to_dblock(b));
1094 1094
1095 bio_endio(bio, 0); 1095 bio_endio(bio, 0);
1096 } 1096 }
1097 1097
1098 static bool spare_migration_bandwidth(struct cache *cache) 1098 static bool spare_migration_bandwidth(struct cache *cache)
1099 { 1099 {
1100 sector_t current_volume = (atomic_read(&cache->nr_migrations) + 1) * 1100 sector_t current_volume = (atomic_read(&cache->nr_migrations) + 1) *
1101 cache->sectors_per_block; 1101 cache->sectors_per_block;
1102 return current_volume < cache->migration_threshold; 1102 return current_volume < cache->migration_threshold;
1103 } 1103 }
1104 1104
1105 static bool is_writethrough_io(struct cache *cache, struct bio *bio, 1105 static bool is_writethrough_io(struct cache *cache, struct bio *bio,
1106 dm_cblock_t cblock) 1106 dm_cblock_t cblock)
1107 { 1107 {
1108 return bio_data_dir(bio) == WRITE && 1108 return bio_data_dir(bio) == WRITE &&
1109 cache->features.write_through && !is_dirty(cache, cblock); 1109 cache->features.write_through && !is_dirty(cache, cblock);
1110 } 1110 }
1111 1111
1112 static void inc_hit_counter(struct cache *cache, struct bio *bio) 1112 static void inc_hit_counter(struct cache *cache, struct bio *bio)
1113 { 1113 {
1114 atomic_inc(bio_data_dir(bio) == READ ? 1114 atomic_inc(bio_data_dir(bio) == READ ?
1115 &cache->stats.read_hit : &cache->stats.write_hit); 1115 &cache->stats.read_hit : &cache->stats.write_hit);
1116 } 1116 }
1117 1117
1118 static void inc_miss_counter(struct cache *cache, struct bio *bio) 1118 static void inc_miss_counter(struct cache *cache, struct bio *bio)
1119 { 1119 {
1120 atomic_inc(bio_data_dir(bio) == READ ? 1120 atomic_inc(bio_data_dir(bio) == READ ?
1121 &cache->stats.read_miss : &cache->stats.write_miss); 1121 &cache->stats.read_miss : &cache->stats.write_miss);
1122 } 1122 }
1123 1123
1124 static void process_bio(struct cache *cache, struct prealloc *structs, 1124 static void process_bio(struct cache *cache, struct prealloc *structs,
1125 struct bio *bio) 1125 struct bio *bio)
1126 { 1126 {
1127 int r; 1127 int r;
1128 bool release_cell = true; 1128 bool release_cell = true;
1129 dm_oblock_t block = get_bio_block(cache, bio); 1129 dm_oblock_t block = get_bio_block(cache, bio);
1130 struct dm_bio_prison_cell *cell_prealloc, *old_ocell, *new_ocell; 1130 struct dm_bio_prison_cell *cell_prealloc, *old_ocell, *new_ocell;
1131 struct policy_result lookup_result; 1131 struct policy_result lookup_result;
1132 size_t pb_data_size = get_per_bio_data_size(cache); 1132 size_t pb_data_size = get_per_bio_data_size(cache);
1133 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); 1133 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
1134 bool discarded_block = is_discarded_oblock(cache, block); 1134 bool discarded_block = is_discarded_oblock(cache, block);
1135 bool can_migrate = discarded_block || spare_migration_bandwidth(cache); 1135 bool can_migrate = discarded_block || spare_migration_bandwidth(cache);
1136 1136
1137 /* 1137 /*
1138 * Check to see if that block is currently migrating. 1138 * Check to see if that block is currently migrating.
1139 */ 1139 */
1140 cell_prealloc = prealloc_get_cell(structs); 1140 cell_prealloc = prealloc_get_cell(structs);
1141 r = bio_detain(cache, block, bio, cell_prealloc, 1141 r = bio_detain(cache, block, bio, cell_prealloc,
1142 (cell_free_fn) prealloc_put_cell, 1142 (cell_free_fn) prealloc_put_cell,
1143 structs, &new_ocell); 1143 structs, &new_ocell);
1144 if (r > 0) 1144 if (r > 0)
1145 return; 1145 return;
1146 1146
1147 r = policy_map(cache->policy, block, true, can_migrate, discarded_block, 1147 r = policy_map(cache->policy, block, true, can_migrate, discarded_block,
1148 bio, &lookup_result); 1148 bio, &lookup_result);
1149 1149
1150 if (r == -EWOULDBLOCK) 1150 if (r == -EWOULDBLOCK)
1151 /* migration has been denied */ 1151 /* migration has been denied */
1152 lookup_result.op = POLICY_MISS; 1152 lookup_result.op = POLICY_MISS;
1153 1153
1154 switch (lookup_result.op) { 1154 switch (lookup_result.op) {
1155 case POLICY_HIT: 1155 case POLICY_HIT:
1156 inc_hit_counter(cache, bio); 1156 inc_hit_counter(cache, bio);
1157 pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); 1157 pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds);
1158 1158
1159 if (is_writethrough_io(cache, bio, lookup_result.cblock)) 1159 if (is_writethrough_io(cache, bio, lookup_result.cblock))
1160 remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock); 1160 remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock);
1161 else 1161 else
1162 remap_to_cache_dirty(cache, bio, block, lookup_result.cblock); 1162 remap_to_cache_dirty(cache, bio, block, lookup_result.cblock);
1163 1163
1164 issue(cache, bio); 1164 issue(cache, bio);
1165 break; 1165 break;
1166 1166
1167 case POLICY_MISS: 1167 case POLICY_MISS:
1168 inc_miss_counter(cache, bio); 1168 inc_miss_counter(cache, bio);
1169 pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); 1169 pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds);
1170 remap_to_origin_clear_discard(cache, bio, block); 1170 remap_to_origin_clear_discard(cache, bio, block);
1171 issue(cache, bio); 1171 issue(cache, bio);
1172 break; 1172 break;
1173 1173
1174 case POLICY_NEW: 1174 case POLICY_NEW:
1175 atomic_inc(&cache->stats.promotion); 1175 atomic_inc(&cache->stats.promotion);
1176 promote(cache, structs, block, lookup_result.cblock, new_ocell); 1176 promote(cache, structs, block, lookup_result.cblock, new_ocell);
1177 release_cell = false; 1177 release_cell = false;
1178 break; 1178 break;
1179 1179
1180 case POLICY_REPLACE: 1180 case POLICY_REPLACE:
1181 cell_prealloc = prealloc_get_cell(structs); 1181 cell_prealloc = prealloc_get_cell(structs);
1182 r = bio_detain(cache, lookup_result.old_oblock, bio, cell_prealloc, 1182 r = bio_detain(cache, lookup_result.old_oblock, bio, cell_prealloc,
1183 (cell_free_fn) prealloc_put_cell, 1183 (cell_free_fn) prealloc_put_cell,
1184 structs, &old_ocell); 1184 structs, &old_ocell);
1185 if (r > 0) { 1185 if (r > 0) {
1186 /* 1186 /*
1187 * We have to be careful to avoid lock inversion of 1187 * We have to be careful to avoid lock inversion of
1188 * the cells. So we back off, and wait for the 1188 * the cells. So we back off, and wait for the
1189 * old_ocell to become free. 1189 * old_ocell to become free.
1190 */ 1190 */
1191 policy_force_mapping(cache->policy, block, 1191 policy_force_mapping(cache->policy, block,
1192 lookup_result.old_oblock); 1192 lookup_result.old_oblock);
1193 atomic_inc(&cache->stats.cache_cell_clash); 1193 atomic_inc(&cache->stats.cache_cell_clash);
1194 break; 1194 break;
1195 } 1195 }
1196 atomic_inc(&cache->stats.demotion); 1196 atomic_inc(&cache->stats.demotion);
1197 atomic_inc(&cache->stats.promotion); 1197 atomic_inc(&cache->stats.promotion);
1198 1198
1199 demote_then_promote(cache, structs, lookup_result.old_oblock, 1199 demote_then_promote(cache, structs, lookup_result.old_oblock,
1200 block, lookup_result.cblock, 1200 block, lookup_result.cblock,
1201 old_ocell, new_ocell); 1201 old_ocell, new_ocell);
1202 release_cell = false; 1202 release_cell = false;
1203 break; 1203 break;
1204 1204
1205 default: 1205 default:
1206 DMERR_LIMIT("%s: erroring bio, unknown policy op: %u", __func__, 1206 DMERR_LIMIT("%s: erroring bio, unknown policy op: %u", __func__,
1207 (unsigned) lookup_result.op); 1207 (unsigned) lookup_result.op);
1208 bio_io_error(bio); 1208 bio_io_error(bio);
1209 } 1209 }
1210 1210
1211 if (release_cell) 1211 if (release_cell)
1212 cell_defer(cache, new_ocell, false); 1212 cell_defer(cache, new_ocell, false);
1213 } 1213 }
1214 1214
1215 static int need_commit_due_to_time(struct cache *cache) 1215 static int need_commit_due_to_time(struct cache *cache)
1216 { 1216 {
1217 return jiffies < cache->last_commit_jiffies || 1217 return jiffies < cache->last_commit_jiffies ||
1218 jiffies > cache->last_commit_jiffies + COMMIT_PERIOD; 1218 jiffies > cache->last_commit_jiffies + COMMIT_PERIOD;
1219 } 1219 }
1220 1220
1221 static int commit_if_needed(struct cache *cache) 1221 static int commit_if_needed(struct cache *cache)
1222 { 1222 {
1223 if (dm_cache_changed_this_transaction(cache->cmd) && 1223 if (dm_cache_changed_this_transaction(cache->cmd) &&
1224 (cache->commit_requested || need_commit_due_to_time(cache))) { 1224 (cache->commit_requested || need_commit_due_to_time(cache))) {
1225 atomic_inc(&cache->stats.commit_count); 1225 atomic_inc(&cache->stats.commit_count);
1226 cache->last_commit_jiffies = jiffies; 1226 cache->last_commit_jiffies = jiffies;
1227 cache->commit_requested = false; 1227 cache->commit_requested = false;
1228 return dm_cache_commit(cache->cmd, false); 1228 return dm_cache_commit(cache->cmd, false);
1229 } 1229 }
1230 1230
1231 return 0; 1231 return 0;
1232 } 1232 }
1233 1233
1234 static void process_deferred_bios(struct cache *cache) 1234 static void process_deferred_bios(struct cache *cache)
1235 { 1235 {
1236 unsigned long flags; 1236 unsigned long flags;
1237 struct bio_list bios; 1237 struct bio_list bios;
1238 struct bio *bio; 1238 struct bio *bio;
1239 struct prealloc structs; 1239 struct prealloc structs;
1240 1240
1241 memset(&structs, 0, sizeof(structs)); 1241 memset(&structs, 0, sizeof(structs));
1242 bio_list_init(&bios); 1242 bio_list_init(&bios);
1243 1243
1244 spin_lock_irqsave(&cache->lock, flags); 1244 spin_lock_irqsave(&cache->lock, flags);
1245 bio_list_merge(&bios, &cache->deferred_bios); 1245 bio_list_merge(&bios, &cache->deferred_bios);
1246 bio_list_init(&cache->deferred_bios); 1246 bio_list_init(&cache->deferred_bios);
1247 spin_unlock_irqrestore(&cache->lock, flags); 1247 spin_unlock_irqrestore(&cache->lock, flags);
1248 1248
1249 while (!bio_list_empty(&bios)) { 1249 while (!bio_list_empty(&bios)) {
1250 /* 1250 /*
1251 * If we've got no free migration structs, and processing 1251 * If we've got no free migration structs, and processing
1252 * this bio might require one, we pause until there are some 1252 * this bio might require one, we pause until there are some
1253 * prepared mappings to process. 1253 * prepared mappings to process.
1254 */ 1254 */
1255 if (prealloc_data_structs(cache, &structs)) { 1255 if (prealloc_data_structs(cache, &structs)) {
1256 spin_lock_irqsave(&cache->lock, flags); 1256 spin_lock_irqsave(&cache->lock, flags);
1257 bio_list_merge(&cache->deferred_bios, &bios); 1257 bio_list_merge(&cache->deferred_bios, &bios);
1258 spin_unlock_irqrestore(&cache->lock, flags); 1258 spin_unlock_irqrestore(&cache->lock, flags);
1259 break; 1259 break;
1260 } 1260 }
1261 1261
1262 bio = bio_list_pop(&bios); 1262 bio = bio_list_pop(&bios);
1263 1263
1264 if (bio->bi_rw & REQ_FLUSH) 1264 if (bio->bi_rw & REQ_FLUSH)
1265 process_flush_bio(cache, bio); 1265 process_flush_bio(cache, bio);
1266 else if (bio->bi_rw & REQ_DISCARD) 1266 else if (bio->bi_rw & REQ_DISCARD)
1267 process_discard_bio(cache, bio); 1267 process_discard_bio(cache, bio);
1268 else 1268 else
1269 process_bio(cache, &structs, bio); 1269 process_bio(cache, &structs, bio);
1270 } 1270 }
1271 1271
1272 prealloc_free_structs(cache, &structs); 1272 prealloc_free_structs(cache, &structs);
1273 } 1273 }
1274 1274
1275 static void process_deferred_flush_bios(struct cache *cache, bool submit_bios) 1275 static void process_deferred_flush_bios(struct cache *cache, bool submit_bios)
1276 { 1276 {
1277 unsigned long flags; 1277 unsigned long flags;
1278 struct bio_list bios; 1278 struct bio_list bios;
1279 struct bio *bio; 1279 struct bio *bio;
1280 1280
1281 bio_list_init(&bios); 1281 bio_list_init(&bios);
1282 1282
1283 spin_lock_irqsave(&cache->lock, flags); 1283 spin_lock_irqsave(&cache->lock, flags);
1284 bio_list_merge(&bios, &cache->deferred_flush_bios); 1284 bio_list_merge(&bios, &cache->deferred_flush_bios);
1285 bio_list_init(&cache->deferred_flush_bios); 1285 bio_list_init(&cache->deferred_flush_bios);
1286 spin_unlock_irqrestore(&cache->lock, flags); 1286 spin_unlock_irqrestore(&cache->lock, flags);
1287 1287
1288 while ((bio = bio_list_pop(&bios))) 1288 while ((bio = bio_list_pop(&bios)))
1289 submit_bios ? generic_make_request(bio) : bio_io_error(bio); 1289 submit_bios ? generic_make_request(bio) : bio_io_error(bio);
1290 } 1290 }
1291 1291
1292 static void process_deferred_writethrough_bios(struct cache *cache) 1292 static void process_deferred_writethrough_bios(struct cache *cache)
1293 { 1293 {
1294 unsigned long flags; 1294 unsigned long flags;
1295 struct bio_list bios; 1295 struct bio_list bios;
1296 struct bio *bio; 1296 struct bio *bio;
1297 1297
1298 bio_list_init(&bios); 1298 bio_list_init(&bios);
1299 1299
1300 spin_lock_irqsave(&cache->lock, flags); 1300 spin_lock_irqsave(&cache->lock, flags);
1301 bio_list_merge(&bios, &cache->deferred_writethrough_bios); 1301 bio_list_merge(&bios, &cache->deferred_writethrough_bios);
1302 bio_list_init(&cache->deferred_writethrough_bios); 1302 bio_list_init(&cache->deferred_writethrough_bios);
1303 spin_unlock_irqrestore(&cache->lock, flags); 1303 spin_unlock_irqrestore(&cache->lock, flags);
1304 1304
1305 while ((bio = bio_list_pop(&bios))) 1305 while ((bio = bio_list_pop(&bios)))
1306 generic_make_request(bio); 1306 generic_make_request(bio);
1307 } 1307 }
1308 1308
1309 static void writeback_some_dirty_blocks(struct cache *cache) 1309 static void writeback_some_dirty_blocks(struct cache *cache)
1310 { 1310 {
1311 int r = 0; 1311 int r = 0;
1312 dm_oblock_t oblock; 1312 dm_oblock_t oblock;
1313 dm_cblock_t cblock; 1313 dm_cblock_t cblock;
1314 struct prealloc structs; 1314 struct prealloc structs;
1315 struct dm_bio_prison_cell *old_ocell; 1315 struct dm_bio_prison_cell *old_ocell;
1316 1316
1317 memset(&structs, 0, sizeof(structs)); 1317 memset(&structs, 0, sizeof(structs));
1318 1318
1319 while (spare_migration_bandwidth(cache)) { 1319 while (spare_migration_bandwidth(cache)) {
1320 if (prealloc_data_structs(cache, &structs)) 1320 if (prealloc_data_structs(cache, &structs))
1321 break; 1321 break;
1322 1322
1323 r = policy_writeback_work(cache->policy, &oblock, &cblock); 1323 r = policy_writeback_work(cache->policy, &oblock, &cblock);
1324 if (r) 1324 if (r)
1325 break; 1325 break;
1326 1326
1327 r = get_cell(cache, oblock, &structs, &old_ocell); 1327 r = get_cell(cache, oblock, &structs, &old_ocell);
1328 if (r) { 1328 if (r) {
1329 policy_set_dirty(cache->policy, oblock); 1329 policy_set_dirty(cache->policy, oblock);
1330 break; 1330 break;
1331 } 1331 }
1332 1332
1333 writeback(cache, &structs, oblock, cblock, old_ocell); 1333 writeback(cache, &structs, oblock, cblock, old_ocell);
1334 } 1334 }
1335 1335
1336 prealloc_free_structs(cache, &structs); 1336 prealloc_free_structs(cache, &structs);
1337 } 1337 }
1338 1338
1339 /*---------------------------------------------------------------- 1339 /*----------------------------------------------------------------
1340 * Main worker loop 1340 * Main worker loop
1341 *--------------------------------------------------------------*/ 1341 *--------------------------------------------------------------*/
1342 static void start_quiescing(struct cache *cache) 1342 static void start_quiescing(struct cache *cache)
1343 { 1343 {
1344 unsigned long flags; 1344 unsigned long flags;
1345 1345
1346 spin_lock_irqsave(&cache->lock, flags); 1346 spin_lock_irqsave(&cache->lock, flags);
1347 cache->quiescing = 1; 1347 cache->quiescing = 1;
1348 spin_unlock_irqrestore(&cache->lock, flags); 1348 spin_unlock_irqrestore(&cache->lock, flags);
1349 } 1349 }
1350 1350
1351 static void stop_quiescing(struct cache *cache) 1351 static void stop_quiescing(struct cache *cache)
1352 { 1352 {
1353 unsigned long flags; 1353 unsigned long flags;
1354 1354
1355 spin_lock_irqsave(&cache->lock, flags); 1355 spin_lock_irqsave(&cache->lock, flags);
1356 cache->quiescing = 0; 1356 cache->quiescing = 0;
1357 spin_unlock_irqrestore(&cache->lock, flags); 1357 spin_unlock_irqrestore(&cache->lock, flags);
1358 } 1358 }
1359 1359
1360 static bool is_quiescing(struct cache *cache) 1360 static bool is_quiescing(struct cache *cache)
1361 { 1361 {
1362 int r; 1362 int r;
1363 unsigned long flags; 1363 unsigned long flags;
1364 1364
1365 spin_lock_irqsave(&cache->lock, flags); 1365 spin_lock_irqsave(&cache->lock, flags);
1366 r = cache->quiescing; 1366 r = cache->quiescing;
1367 spin_unlock_irqrestore(&cache->lock, flags); 1367 spin_unlock_irqrestore(&cache->lock, flags);
1368 1368
1369 return r; 1369 return r;
1370 } 1370 }
1371 1371
1372 static void wait_for_migrations(struct cache *cache) 1372 static void wait_for_migrations(struct cache *cache)
1373 { 1373 {
1374 wait_event(cache->migration_wait, !atomic_read(&cache->nr_migrations)); 1374 wait_event(cache->migration_wait, !atomic_read(&cache->nr_migrations));
1375 } 1375 }
1376 1376
1377 static void stop_worker(struct cache *cache) 1377 static void stop_worker(struct cache *cache)
1378 { 1378 {
1379 cancel_delayed_work(&cache->waker); 1379 cancel_delayed_work(&cache->waker);
1380 flush_workqueue(cache->wq); 1380 flush_workqueue(cache->wq);
1381 } 1381 }
1382 1382
1383 static void requeue_deferred_io(struct cache *cache) 1383 static void requeue_deferred_io(struct cache *cache)
1384 { 1384 {
1385 struct bio *bio; 1385 struct bio *bio;
1386 struct bio_list bios; 1386 struct bio_list bios;
1387 1387
1388 bio_list_init(&bios); 1388 bio_list_init(&bios);
1389 bio_list_merge(&bios, &cache->deferred_bios); 1389 bio_list_merge(&bios, &cache->deferred_bios);
1390 bio_list_init(&cache->deferred_bios); 1390 bio_list_init(&cache->deferred_bios);
1391 1391
1392 while ((bio = bio_list_pop(&bios))) 1392 while ((bio = bio_list_pop(&bios)))
1393 bio_endio(bio, DM_ENDIO_REQUEUE); 1393 bio_endio(bio, DM_ENDIO_REQUEUE);
1394 } 1394 }
1395 1395
1396 static int more_work(struct cache *cache) 1396 static int more_work(struct cache *cache)
1397 { 1397 {
1398 if (is_quiescing(cache)) 1398 if (is_quiescing(cache))
1399 return !list_empty(&cache->quiesced_migrations) || 1399 return !list_empty(&cache->quiesced_migrations) ||
1400 !list_empty(&cache->completed_migrations) || 1400 !list_empty(&cache->completed_migrations) ||
1401 !list_empty(&cache->need_commit_migrations); 1401 !list_empty(&cache->need_commit_migrations);
1402 else 1402 else
1403 return !bio_list_empty(&cache->deferred_bios) || 1403 return !bio_list_empty(&cache->deferred_bios) ||
1404 !bio_list_empty(&cache->deferred_flush_bios) || 1404 !bio_list_empty(&cache->deferred_flush_bios) ||
1405 !bio_list_empty(&cache->deferred_writethrough_bios) || 1405 !bio_list_empty(&cache->deferred_writethrough_bios) ||
1406 !list_empty(&cache->quiesced_migrations) || 1406 !list_empty(&cache->quiesced_migrations) ||
1407 !list_empty(&cache->completed_migrations) || 1407 !list_empty(&cache->completed_migrations) ||
1408 !list_empty(&cache->need_commit_migrations); 1408 !list_empty(&cache->need_commit_migrations);
1409 } 1409 }
1410 1410
1411 static void do_worker(struct work_struct *ws) 1411 static void do_worker(struct work_struct *ws)
1412 { 1412 {
1413 struct cache *cache = container_of(ws, struct cache, worker); 1413 struct cache *cache = container_of(ws, struct cache, worker);
1414 1414
1415 do { 1415 do {
1416 if (!is_quiescing(cache)) 1416 if (!is_quiescing(cache))
1417 process_deferred_bios(cache); 1417 process_deferred_bios(cache);
1418 1418
1419 process_migrations(cache, &cache->quiesced_migrations, issue_copy); 1419 process_migrations(cache, &cache->quiesced_migrations, issue_copy);
1420 process_migrations(cache, &cache->completed_migrations, complete_migration); 1420 process_migrations(cache, &cache->completed_migrations, complete_migration);
1421 1421
1422 writeback_some_dirty_blocks(cache); 1422 writeback_some_dirty_blocks(cache);
1423 1423
1424 process_deferred_writethrough_bios(cache); 1424 process_deferred_writethrough_bios(cache);
1425 1425
1426 if (commit_if_needed(cache)) { 1426 if (commit_if_needed(cache)) {
1427 process_deferred_flush_bios(cache, false); 1427 process_deferred_flush_bios(cache, false);
1428 1428
1429 /* 1429 /*
1430 * FIXME: rollback metadata or just go into a 1430 * FIXME: rollback metadata or just go into a
1431 * failure mode and error everything 1431 * failure mode and error everything
1432 */ 1432 */
1433 } else { 1433 } else {
1434 process_deferred_flush_bios(cache, true); 1434 process_deferred_flush_bios(cache, true);
1435 process_migrations(cache, &cache->need_commit_migrations, 1435 process_migrations(cache, &cache->need_commit_migrations,
1436 migration_success_post_commit); 1436 migration_success_post_commit);
1437 } 1437 }
1438 } while (more_work(cache)); 1438 } while (more_work(cache));
1439 } 1439 }
1440 1440
1441 /* 1441 /*
1442 * We want to commit periodically so that not too much 1442 * We want to commit periodically so that not too much
1443 * unwritten metadata builds up. 1443 * unwritten metadata builds up.
1444 */ 1444 */
1445 static void do_waker(struct work_struct *ws) 1445 static void do_waker(struct work_struct *ws)
1446 { 1446 {
1447 struct cache *cache = container_of(to_delayed_work(ws), struct cache, waker); 1447 struct cache *cache = container_of(to_delayed_work(ws), struct cache, waker);
1448 wake_worker(cache); 1448 wake_worker(cache);
1449 queue_delayed_work(cache->wq, &cache->waker, COMMIT_PERIOD); 1449 queue_delayed_work(cache->wq, &cache->waker, COMMIT_PERIOD);
1450 } 1450 }
1451 1451
1452 /*----------------------------------------------------------------*/ 1452 /*----------------------------------------------------------------*/
1453 1453
1454 static int is_congested(struct dm_dev *dev, int bdi_bits) 1454 static int is_congested(struct dm_dev *dev, int bdi_bits)
1455 { 1455 {
1456 struct request_queue *q = bdev_get_queue(dev->bdev); 1456 struct request_queue *q = bdev_get_queue(dev->bdev);
1457 return bdi_congested(&q->backing_dev_info, bdi_bits); 1457 return bdi_congested(&q->backing_dev_info, bdi_bits);
1458 } 1458 }
1459 1459
1460 static int cache_is_congested(struct dm_target_callbacks *cb, int bdi_bits) 1460 static int cache_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
1461 { 1461 {
1462 struct cache *cache = container_of(cb, struct cache, callbacks); 1462 struct cache *cache = container_of(cb, struct cache, callbacks);
1463 1463
1464 return is_congested(cache->origin_dev, bdi_bits) || 1464 return is_congested(cache->origin_dev, bdi_bits) ||
1465 is_congested(cache->cache_dev, bdi_bits); 1465 is_congested(cache->cache_dev, bdi_bits);
1466 } 1466 }
1467 1467
1468 /*---------------------------------------------------------------- 1468 /*----------------------------------------------------------------
1469 * Target methods 1469 * Target methods
1470 *--------------------------------------------------------------*/ 1470 *--------------------------------------------------------------*/
1471 1471
1472 /* 1472 /*
1473 * This function gets called on the error paths of the constructor, so we 1473 * This function gets called on the error paths of the constructor, so we
1474 * have to cope with a partially initialised struct. 1474 * have to cope with a partially initialised struct.
1475 */ 1475 */
1476 static void destroy(struct cache *cache) 1476 static void destroy(struct cache *cache)
1477 { 1477 {
1478 unsigned i; 1478 unsigned i;
1479 1479
1480 if (cache->next_migration) 1480 if (cache->next_migration)
1481 mempool_free(cache->next_migration, cache->migration_pool); 1481 mempool_free(cache->next_migration, cache->migration_pool);
1482 1482
1483 if (cache->migration_pool) 1483 if (cache->migration_pool)
1484 mempool_destroy(cache->migration_pool); 1484 mempool_destroy(cache->migration_pool);
1485 1485
1486 if (cache->all_io_ds) 1486 if (cache->all_io_ds)
1487 dm_deferred_set_destroy(cache->all_io_ds); 1487 dm_deferred_set_destroy(cache->all_io_ds);
1488 1488
1489 if (cache->prison) 1489 if (cache->prison)
1490 dm_bio_prison_destroy(cache->prison); 1490 dm_bio_prison_destroy(cache->prison);
1491 1491
1492 if (cache->wq) 1492 if (cache->wq)
1493 destroy_workqueue(cache->wq); 1493 destroy_workqueue(cache->wq);
1494 1494
1495 if (cache->dirty_bitset) 1495 if (cache->dirty_bitset)
1496 free_bitset(cache->dirty_bitset); 1496 free_bitset(cache->dirty_bitset);
1497 1497
1498 if (cache->discard_bitset) 1498 if (cache->discard_bitset)
1499 free_bitset(cache->discard_bitset); 1499 free_bitset(cache->discard_bitset);
1500 1500
1501 if (cache->copier) 1501 if (cache->copier)
1502 dm_kcopyd_client_destroy(cache->copier); 1502 dm_kcopyd_client_destroy(cache->copier);
1503 1503
1504 if (cache->cmd) 1504 if (cache->cmd)
1505 dm_cache_metadata_close(cache->cmd); 1505 dm_cache_metadata_close(cache->cmd);
1506 1506
1507 if (cache->metadata_dev) 1507 if (cache->metadata_dev)
1508 dm_put_device(cache->ti, cache->metadata_dev); 1508 dm_put_device(cache->ti, cache->metadata_dev);
1509 1509
1510 if (cache->origin_dev) 1510 if (cache->origin_dev)
1511 dm_put_device(cache->ti, cache->origin_dev); 1511 dm_put_device(cache->ti, cache->origin_dev);
1512 1512
1513 if (cache->cache_dev) 1513 if (cache->cache_dev)
1514 dm_put_device(cache->ti, cache->cache_dev); 1514 dm_put_device(cache->ti, cache->cache_dev);
1515 1515
1516 if (cache->policy) 1516 if (cache->policy)
1517 dm_cache_policy_destroy(cache->policy); 1517 dm_cache_policy_destroy(cache->policy);
1518 1518
1519 for (i = 0; i < cache->nr_ctr_args ; i++) 1519 for (i = 0; i < cache->nr_ctr_args ; i++)
1520 kfree(cache->ctr_args[i]); 1520 kfree(cache->ctr_args[i]);
1521 kfree(cache->ctr_args); 1521 kfree(cache->ctr_args);
1522 1522
1523 kfree(cache); 1523 kfree(cache);
1524 } 1524 }
1525 1525
1526 static void cache_dtr(struct dm_target *ti) 1526 static void cache_dtr(struct dm_target *ti)
1527 { 1527 {
1528 struct cache *cache = ti->private; 1528 struct cache *cache = ti->private;
1529 1529
1530 destroy(cache); 1530 destroy(cache);
1531 } 1531 }
1532 1532
1533 static sector_t get_dev_size(struct dm_dev *dev) 1533 static sector_t get_dev_size(struct dm_dev *dev)
1534 { 1534 {
1535 return i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT; 1535 return i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT;
1536 } 1536 }
1537 1537
1538 /*----------------------------------------------------------------*/ 1538 /*----------------------------------------------------------------*/
1539 1539
1540 /* 1540 /*
1541 * Construct a cache device mapping. 1541 * Construct a cache device mapping.
1542 * 1542 *
1543 * cache <metadata dev> <cache dev> <origin dev> <block size> 1543 * cache <metadata dev> <cache dev> <origin dev> <block size>
1544 * <#feature args> [<feature arg>]* 1544 * <#feature args> [<feature arg>]*
1545 * <policy> <#policy args> [<policy arg>]* 1545 * <policy> <#policy args> [<policy arg>]*
1546 * 1546 *
1547 * metadata dev : fast device holding the persistent metadata 1547 * metadata dev : fast device holding the persistent metadata
1548 * cache dev : fast device holding cached data blocks 1548 * cache dev : fast device holding cached data blocks
1549 * origin dev : slow device holding original data blocks 1549 * origin dev : slow device holding original data blocks
1550 * block size : cache unit size in sectors 1550 * block size : cache unit size in sectors
1551 * 1551 *
1552 * #feature args : number of feature arguments passed 1552 * #feature args : number of feature arguments passed
1553 * feature args : writethrough. (The default is writeback.) 1553 * feature args : writethrough. (The default is writeback.)
1554 * 1554 *
1555 * policy : the replacement policy to use 1555 * policy : the replacement policy to use
1556 * #policy args : an even number of policy arguments corresponding 1556 * #policy args : an even number of policy arguments corresponding
1557 * to key/value pairs passed to the policy 1557 * to key/value pairs passed to the policy
1558 * policy args : key/value pairs passed to the policy 1558 * policy args : key/value pairs passed to the policy
1559 * E.g. 'sequential_threshold 1024' 1559 * E.g. 'sequential_threshold 1024'
1560 * See cache-policies.txt for details. 1560 * See cache-policies.txt for details.
1561 * 1561 *
1562 * Optional feature arguments are: 1562 * Optional feature arguments are:
1563 * writethrough : write through caching that prohibits cache block 1563 * writethrough : write through caching that prohibits cache block
1564 * content from being different from origin block content. 1564 * content from being different from origin block content.
1565 * Without this argument, the default behaviour is to write 1565 * Without this argument, the default behaviour is to write
1566 * back cache block contents later for performance reasons, 1566 * back cache block contents later for performance reasons,
1567 * so they may differ from the corresponding origin blocks. 1567 * so they may differ from the corresponding origin blocks.
1568 */ 1568 */
1569 struct cache_args { 1569 struct cache_args {
1570 struct dm_target *ti; 1570 struct dm_target *ti;
1571 1571
1572 struct dm_dev *metadata_dev; 1572 struct dm_dev *metadata_dev;
1573 1573
1574 struct dm_dev *cache_dev; 1574 struct dm_dev *cache_dev;
1575 sector_t cache_sectors; 1575 sector_t cache_sectors;
1576 1576
1577 struct dm_dev *origin_dev; 1577 struct dm_dev *origin_dev;
1578 sector_t origin_sectors; 1578 sector_t origin_sectors;
1579 1579
1580 uint32_t block_size; 1580 uint32_t block_size;
1581 1581
1582 const char *policy_name; 1582 const char *policy_name;
1583 int policy_argc; 1583 int policy_argc;
1584 const char **policy_argv; 1584 const char **policy_argv;
1585 1585
1586 struct cache_features features; 1586 struct cache_features features;
1587 }; 1587 };
1588 1588
1589 static void destroy_cache_args(struct cache_args *ca) 1589 static void destroy_cache_args(struct cache_args *ca)
1590 { 1590 {
1591 if (ca->metadata_dev) 1591 if (ca->metadata_dev)
1592 dm_put_device(ca->ti, ca->metadata_dev); 1592 dm_put_device(ca->ti, ca->metadata_dev);
1593 1593
1594 if (ca->cache_dev) 1594 if (ca->cache_dev)
1595 dm_put_device(ca->ti, ca->cache_dev); 1595 dm_put_device(ca->ti, ca->cache_dev);
1596 1596
1597 if (ca->origin_dev) 1597 if (ca->origin_dev)
1598 dm_put_device(ca->ti, ca->origin_dev); 1598 dm_put_device(ca->ti, ca->origin_dev);
1599 1599
1600 kfree(ca); 1600 kfree(ca);
1601 } 1601 }
1602 1602
1603 static bool at_least_one_arg(struct dm_arg_set *as, char **error) 1603 static bool at_least_one_arg(struct dm_arg_set *as, char **error)
1604 { 1604 {
1605 if (!as->argc) { 1605 if (!as->argc) {
1606 *error = "Insufficient args"; 1606 *error = "Insufficient args";
1607 return false; 1607 return false;
1608 } 1608 }
1609 1609
1610 return true; 1610 return true;
1611 } 1611 }
1612 1612
1613 static int parse_metadata_dev(struct cache_args *ca, struct dm_arg_set *as, 1613 static int parse_metadata_dev(struct cache_args *ca, struct dm_arg_set *as,
1614 char **error) 1614 char **error)
1615 { 1615 {
1616 int r; 1616 int r;
1617 sector_t metadata_dev_size; 1617 sector_t metadata_dev_size;
1618 char b[BDEVNAME_SIZE]; 1618 char b[BDEVNAME_SIZE];
1619 1619
1620 if (!at_least_one_arg(as, error)) 1620 if (!at_least_one_arg(as, error))
1621 return -EINVAL; 1621 return -EINVAL;
1622 1622
1623 r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE, 1623 r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE,
1624 &ca->metadata_dev); 1624 &ca->metadata_dev);
1625 if (r) { 1625 if (r) {
1626 *error = "Error opening metadata device"; 1626 *error = "Error opening metadata device";
1627 return r; 1627 return r;
1628 } 1628 }
1629 1629
1630 metadata_dev_size = get_dev_size(ca->metadata_dev); 1630 metadata_dev_size = get_dev_size(ca->metadata_dev);
1631 if (metadata_dev_size > DM_CACHE_METADATA_MAX_SECTORS_WARNING) 1631 if (metadata_dev_size > DM_CACHE_METADATA_MAX_SECTORS_WARNING)
1632 DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.", 1632 DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
1633 bdevname(ca->metadata_dev->bdev, b), THIN_METADATA_MAX_SECTORS); 1633 bdevname(ca->metadata_dev->bdev, b), THIN_METADATA_MAX_SECTORS);
1634 1634
1635 return 0; 1635 return 0;
1636 } 1636 }
1637 1637
1638 static int parse_cache_dev(struct cache_args *ca, struct dm_arg_set *as, 1638 static int parse_cache_dev(struct cache_args *ca, struct dm_arg_set *as,
1639 char **error) 1639 char **error)
1640 { 1640 {
1641 int r; 1641 int r;
1642 1642
1643 if (!at_least_one_arg(as, error)) 1643 if (!at_least_one_arg(as, error))
1644 return -EINVAL; 1644 return -EINVAL;
1645 1645
1646 r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE, 1646 r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE,
1647 &ca->cache_dev); 1647 &ca->cache_dev);
1648 if (r) { 1648 if (r) {
1649 *error = "Error opening cache device"; 1649 *error = "Error opening cache device";
1650 return r; 1650 return r;
1651 } 1651 }
1652 ca->cache_sectors = get_dev_size(ca->cache_dev); 1652 ca->cache_sectors = get_dev_size(ca->cache_dev);
1653 1653
1654 return 0; 1654 return 0;
1655 } 1655 }
1656 1656
1657 static int parse_origin_dev(struct cache_args *ca, struct dm_arg_set *as, 1657 static int parse_origin_dev(struct cache_args *ca, struct dm_arg_set *as,
1658 char **error) 1658 char **error)
1659 { 1659 {
1660 int r; 1660 int r;
1661 1661
1662 if (!at_least_one_arg(as, error)) 1662 if (!at_least_one_arg(as, error))
1663 return -EINVAL; 1663 return -EINVAL;
1664 1664
1665 r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE, 1665 r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE,
1666 &ca->origin_dev); 1666 &ca->origin_dev);
1667 if (r) { 1667 if (r) {
1668 *error = "Error opening origin device"; 1668 *error = "Error opening origin device";
1669 return r; 1669 return r;
1670 } 1670 }
1671 1671
1672 ca->origin_sectors = get_dev_size(ca->origin_dev); 1672 ca->origin_sectors = get_dev_size(ca->origin_dev);
1673 if (ca->ti->len > ca->origin_sectors) { 1673 if (ca->ti->len > ca->origin_sectors) {
1674 *error = "Device size larger than cached device"; 1674 *error = "Device size larger than cached device";
1675 return -EINVAL; 1675 return -EINVAL;
1676 } 1676 }
1677 1677
1678 return 0; 1678 return 0;
1679 } 1679 }
1680 1680
1681 static int parse_block_size(struct cache_args *ca, struct dm_arg_set *as, 1681 static int parse_block_size(struct cache_args *ca, struct dm_arg_set *as,
1682 char **error) 1682 char **error)
1683 { 1683 {
1684 unsigned long tmp; 1684 unsigned long tmp;
1685 1685
1686 if (!at_least_one_arg(as, error)) 1686 if (!at_least_one_arg(as, error))
1687 return -EINVAL; 1687 return -EINVAL;
1688 1688
1689 if (kstrtoul(dm_shift_arg(as), 10, &tmp) || !tmp || 1689 if (kstrtoul(dm_shift_arg(as), 10, &tmp) || !tmp ||
1690 tmp < DATA_DEV_BLOCK_SIZE_MIN_SECTORS || 1690 tmp < DATA_DEV_BLOCK_SIZE_MIN_SECTORS ||
1691 tmp & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) { 1691 tmp & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) {
1692 *error = "Invalid data block size"; 1692 *error = "Invalid data block size";
1693 return -EINVAL; 1693 return -EINVAL;
1694 } 1694 }
1695 1695
1696 if (tmp > ca->cache_sectors) { 1696 if (tmp > ca->cache_sectors) {
1697 *error = "Data block size is larger than the cache device"; 1697 *error = "Data block size is larger than the cache device";
1698 return -EINVAL; 1698 return -EINVAL;
1699 } 1699 }
1700 1700
1701 ca->block_size = tmp; 1701 ca->block_size = tmp;
1702 1702
1703 return 0; 1703 return 0;
1704 } 1704 }
1705 1705
1706 static void init_features(struct cache_features *cf) 1706 static void init_features(struct cache_features *cf)
1707 { 1707 {
1708 cf->mode = CM_WRITE; 1708 cf->mode = CM_WRITE;
1709 cf->write_through = false; 1709 cf->write_through = false;
1710 } 1710 }
1711 1711
1712 static int parse_features(struct cache_args *ca, struct dm_arg_set *as, 1712 static int parse_features(struct cache_args *ca, struct dm_arg_set *as,
1713 char **error) 1713 char **error)
1714 { 1714 {
1715 static struct dm_arg _args[] = { 1715 static struct dm_arg _args[] = {
1716 {0, 1, "Invalid number of cache feature arguments"}, 1716 {0, 1, "Invalid number of cache feature arguments"},
1717 }; 1717 };
1718 1718
1719 int r; 1719 int r;
1720 unsigned argc; 1720 unsigned argc;
1721 const char *arg; 1721 const char *arg;
1722 struct cache_features *cf = &ca->features; 1722 struct cache_features *cf = &ca->features;
1723 1723
1724 init_features(cf); 1724 init_features(cf);
1725 1725
1726 r = dm_read_arg_group(_args, as, &argc, error); 1726 r = dm_read_arg_group(_args, as, &argc, error);
1727 if (r) 1727 if (r)
1728 return -EINVAL; 1728 return -EINVAL;
1729 1729
1730 while (argc--) { 1730 while (argc--) {
1731 arg = dm_shift_arg(as); 1731 arg = dm_shift_arg(as);
1732 1732
1733 if (!strcasecmp(arg, "writeback")) 1733 if (!strcasecmp(arg, "writeback"))
1734 cf->write_through = false; 1734 cf->write_through = false;
1735 1735
1736 else if (!strcasecmp(arg, "writethrough")) 1736 else if (!strcasecmp(arg, "writethrough"))
1737 cf->write_through = true; 1737 cf->write_through = true;
1738 1738
1739 else { 1739 else {
1740 *error = "Unrecognised cache feature requested"; 1740 *error = "Unrecognised cache feature requested";
1741 return -EINVAL; 1741 return -EINVAL;
1742 } 1742 }
1743 } 1743 }
1744 1744
1745 return 0; 1745 return 0;
1746 } 1746 }
1747 1747
1748 static int parse_policy(struct cache_args *ca, struct dm_arg_set *as, 1748 static int parse_policy(struct cache_args *ca, struct dm_arg_set *as,
1749 char **error) 1749 char **error)
1750 { 1750 {
1751 static struct dm_arg _args[] = { 1751 static struct dm_arg _args[] = {
1752 {0, 1024, "Invalid number of policy arguments"}, 1752 {0, 1024, "Invalid number of policy arguments"},
1753 }; 1753 };
1754 1754
1755 int r; 1755 int r;
1756 1756
1757 if (!at_least_one_arg(as, error)) 1757 if (!at_least_one_arg(as, error))
1758 return -EINVAL; 1758 return -EINVAL;
1759 1759
1760 ca->policy_name = dm_shift_arg(as); 1760 ca->policy_name = dm_shift_arg(as);
1761 1761
1762 r = dm_read_arg_group(_args, as, &ca->policy_argc, error); 1762 r = dm_read_arg_group(_args, as, &ca->policy_argc, error);
1763 if (r) 1763 if (r)
1764 return -EINVAL; 1764 return -EINVAL;
1765 1765
1766 ca->policy_argv = (const char **)as->argv; 1766 ca->policy_argv = (const char **)as->argv;
1767 dm_consume_args(as, ca->policy_argc); 1767 dm_consume_args(as, ca->policy_argc);
1768 1768
1769 return 0; 1769 return 0;
1770 } 1770 }
1771 1771
1772 static int parse_cache_args(struct cache_args *ca, int argc, char **argv, 1772 static int parse_cache_args(struct cache_args *ca, int argc, char **argv,
1773 char **error) 1773 char **error)
1774 { 1774 {
1775 int r; 1775 int r;
1776 struct dm_arg_set as; 1776 struct dm_arg_set as;
1777 1777
1778 as.argc = argc; 1778 as.argc = argc;
1779 as.argv = argv; 1779 as.argv = argv;
1780 1780
1781 r = parse_metadata_dev(ca, &as, error); 1781 r = parse_metadata_dev(ca, &as, error);
1782 if (r) 1782 if (r)
1783 return r; 1783 return r;
1784 1784
1785 r = parse_cache_dev(ca, &as, error); 1785 r = parse_cache_dev(ca, &as, error);
1786 if (r) 1786 if (r)
1787 return r; 1787 return r;
1788 1788
1789 r = parse_origin_dev(ca, &as, error); 1789 r = parse_origin_dev(ca, &as, error);
1790 if (r) 1790 if (r)
1791 return r; 1791 return r;
1792 1792
1793 r = parse_block_size(ca, &as, error); 1793 r = parse_block_size(ca, &as, error);
1794 if (r) 1794 if (r)
1795 return r; 1795 return r;
1796 1796
1797 r = parse_features(ca, &as, error); 1797 r = parse_features(ca, &as, error);
1798 if (r) 1798 if (r)
1799 return r; 1799 return r;
1800 1800
1801 r = parse_policy(ca, &as, error); 1801 r = parse_policy(ca, &as, error);
1802 if (r) 1802 if (r)
1803 return r; 1803 return r;
1804 1804
1805 return 0; 1805 return 0;
1806 } 1806 }
1807 1807
1808 /*----------------------------------------------------------------*/ 1808 /*----------------------------------------------------------------*/
1809 1809
1810 static struct kmem_cache *migration_cache; 1810 static struct kmem_cache *migration_cache;
1811 1811
1812 static int set_config_values(struct dm_cache_policy *p, int argc, const char **argv) 1812 static int set_config_values(struct dm_cache_policy *p, int argc, const char **argv)
1813 { 1813 {
1814 int r = 0; 1814 int r = 0;
1815 1815
1816 if (argc & 1) { 1816 if (argc & 1) {
1817 DMWARN("Odd number of policy arguments given but they should be <key> <value> pairs."); 1817 DMWARN("Odd number of policy arguments given but they should be <key> <value> pairs.");
1818 return -EINVAL; 1818 return -EINVAL;
1819 } 1819 }
1820 1820
1821 while (argc) { 1821 while (argc) {
1822 r = policy_set_config_value(p, argv[0], argv[1]); 1822 r = policy_set_config_value(p, argv[0], argv[1]);
1823 if (r) { 1823 if (r) {
1824 DMWARN("policy_set_config_value failed: key = '%s', value = '%s'", 1824 DMWARN("policy_set_config_value failed: key = '%s', value = '%s'",
1825 argv[0], argv[1]); 1825 argv[0], argv[1]);
1826 return r; 1826 return r;
1827 } 1827 }
1828 1828
1829 argc -= 2; 1829 argc -= 2;
1830 argv += 2; 1830 argv += 2;
1831 } 1831 }
1832 1832
1833 return r; 1833 return r;
1834 } 1834 }
1835 1835
1836 static int create_cache_policy(struct cache *cache, struct cache_args *ca, 1836 static int create_cache_policy(struct cache *cache, struct cache_args *ca,
1837 char **error) 1837 char **error)
1838 { 1838 {
1839 int r; 1839 int r;
1840 1840
1841 cache->policy = dm_cache_policy_create(ca->policy_name, 1841 cache->policy = dm_cache_policy_create(ca->policy_name,
1842 cache->cache_size, 1842 cache->cache_size,
1843 cache->origin_sectors, 1843 cache->origin_sectors,
1844 cache->sectors_per_block); 1844 cache->sectors_per_block);
1845 if (!cache->policy) { 1845 if (!cache->policy) {
1846 *error = "Error creating cache's policy"; 1846 *error = "Error creating cache's policy";
1847 return -ENOMEM; 1847 return -ENOMEM;
1848 } 1848 }
1849 1849
1850 r = set_config_values(cache->policy, ca->policy_argc, ca->policy_argv); 1850 r = set_config_values(cache->policy, ca->policy_argc, ca->policy_argv);
1851 if (r) { 1851 if (r) {
1852 *error = "Error setting cache policy's config values"; 1852 *error = "Error setting cache policy's config values";
1853 dm_cache_policy_destroy(cache->policy); 1853 dm_cache_policy_destroy(cache->policy);
1854 cache->policy = NULL; 1854 cache->policy = NULL;
1855 } 1855 }
1856 1856
1857 return r; 1857 return r;
1858 } 1858 }
1859 1859
1860 /* 1860 /*
1861 * We want the discard block size to be a power of two, at least the size 1861 * We want the discard block size to be a power of two, at least the size
1862 * of the cache block size, and have no more than 2^14 discard blocks 1862 * of the cache block size, and have no more than 2^14 discard blocks
1863 * across the origin. 1863 * across the origin.
1864 */ 1864 */
1865 #define MAX_DISCARD_BLOCKS (1 << 14) 1865 #define MAX_DISCARD_BLOCKS (1 << 14)
1866 1866
1867 static bool too_many_discard_blocks(sector_t discard_block_size, 1867 static bool too_many_discard_blocks(sector_t discard_block_size,
1868 sector_t origin_size) 1868 sector_t origin_size)
1869 { 1869 {
1870 (void) sector_div(origin_size, discard_block_size); 1870 (void) sector_div(origin_size, discard_block_size);
1871 1871
1872 return origin_size > MAX_DISCARD_BLOCKS; 1872 return origin_size > MAX_DISCARD_BLOCKS;
1873 } 1873 }
1874 1874
1875 static sector_t calculate_discard_block_size(sector_t cache_block_size, 1875 static sector_t calculate_discard_block_size(sector_t cache_block_size,
1876 sector_t origin_size) 1876 sector_t origin_size)
1877 { 1877 {
1878 sector_t discard_block_size; 1878 sector_t discard_block_size;
1879 1879
1880 discard_block_size = roundup_pow_of_two(cache_block_size); 1880 discard_block_size = roundup_pow_of_two(cache_block_size);
1881 1881
1882 if (origin_size) 1882 if (origin_size)
1883 while (too_many_discard_blocks(discard_block_size, origin_size)) 1883 while (too_many_discard_blocks(discard_block_size, origin_size))
1884 discard_block_size *= 2; 1884 discard_block_size *= 2;
1885 1885
1886 return discard_block_size; 1886 return discard_block_size;
1887 } 1887 }
1888 1888
1889 #define DEFAULT_MIGRATION_THRESHOLD (2048 * 100) 1889 #define DEFAULT_MIGRATION_THRESHOLD (2048 * 100)
1890 1890
1891 static int cache_create(struct cache_args *ca, struct cache **result) 1891 static int cache_create(struct cache_args *ca, struct cache **result)
1892 { 1892 {
1893 int r = 0; 1893 int r = 0;
1894 char **error = &ca->ti->error; 1894 char **error = &ca->ti->error;
1895 struct cache *cache; 1895 struct cache *cache;
1896 struct dm_target *ti = ca->ti; 1896 struct dm_target *ti = ca->ti;
1897 dm_block_t origin_blocks; 1897 dm_block_t origin_blocks;
1898 struct dm_cache_metadata *cmd; 1898 struct dm_cache_metadata *cmd;
1899 bool may_format = ca->features.mode == CM_WRITE; 1899 bool may_format = ca->features.mode == CM_WRITE;
1900 1900
1901 cache = kzalloc(sizeof(*cache), GFP_KERNEL); 1901 cache = kzalloc(sizeof(*cache), GFP_KERNEL);
1902 if (!cache) 1902 if (!cache)
1903 return -ENOMEM; 1903 return -ENOMEM;
1904 1904
1905 cache->ti = ca->ti; 1905 cache->ti = ca->ti;
1906 ti->private = cache; 1906 ti->private = cache;
1907 ti->num_flush_bios = 2; 1907 ti->num_flush_bios = 2;
1908 ti->flush_supported = true; 1908 ti->flush_supported = true;
1909 1909
1910 ti->num_discard_bios = 1; 1910 ti->num_discard_bios = 1;
1911 ti->discards_supported = true; 1911 ti->discards_supported = true;
1912 ti->discard_zeroes_data_unsupported = true; 1912 ti->discard_zeroes_data_unsupported = true;
1913 1913
1914 memcpy(&cache->features, &ca->features, sizeof(cache->features)); 1914 memcpy(&cache->features, &ca->features, sizeof(cache->features));
1915 ti->per_bio_data_size = get_per_bio_data_size(cache); 1915 ti->per_bio_data_size = get_per_bio_data_size(cache);
1916 1916
1917 cache->callbacks.congested_fn = cache_is_congested; 1917 cache->callbacks.congested_fn = cache_is_congested;
1918 dm_table_add_target_callbacks(ti->table, &cache->callbacks); 1918 dm_table_add_target_callbacks(ti->table, &cache->callbacks);
1919 1919
1920 cache->metadata_dev = ca->metadata_dev; 1920 cache->metadata_dev = ca->metadata_dev;
1921 cache->origin_dev = ca->origin_dev; 1921 cache->origin_dev = ca->origin_dev;
1922 cache->cache_dev = ca->cache_dev; 1922 cache->cache_dev = ca->cache_dev;
1923 1923
1924 ca->metadata_dev = ca->origin_dev = ca->cache_dev = NULL; 1924 ca->metadata_dev = ca->origin_dev = ca->cache_dev = NULL;
1925 1925
1926 /* FIXME: factor out this whole section */ 1926 /* FIXME: factor out this whole section */
1927 origin_blocks = cache->origin_sectors = ca->origin_sectors; 1927 origin_blocks = cache->origin_sectors = ca->origin_sectors;
1928 origin_blocks = block_div(origin_blocks, ca->block_size); 1928 origin_blocks = block_div(origin_blocks, ca->block_size);
1929 cache->origin_blocks = to_oblock(origin_blocks); 1929 cache->origin_blocks = to_oblock(origin_blocks);
1930 1930
1931 cache->sectors_per_block = ca->block_size; 1931 cache->sectors_per_block = ca->block_size;
1932 if (dm_set_target_max_io_len(ti, cache->sectors_per_block)) { 1932 if (dm_set_target_max_io_len(ti, cache->sectors_per_block)) {
1933 r = -EINVAL; 1933 r = -EINVAL;
1934 goto bad; 1934 goto bad;
1935 } 1935 }
1936 1936
1937 if (ca->block_size & (ca->block_size - 1)) { 1937 if (ca->block_size & (ca->block_size - 1)) {
1938 dm_block_t cache_size = ca->cache_sectors; 1938 dm_block_t cache_size = ca->cache_sectors;
1939 1939
1940 cache->sectors_per_block_shift = -1; 1940 cache->sectors_per_block_shift = -1;
1941 cache_size = block_div(cache_size, ca->block_size); 1941 cache_size = block_div(cache_size, ca->block_size);
1942 cache->cache_size = to_cblock(cache_size); 1942 cache->cache_size = to_cblock(cache_size);
1943 } else { 1943 } else {
1944 cache->sectors_per_block_shift = __ffs(ca->block_size); 1944 cache->sectors_per_block_shift = __ffs(ca->block_size);
1945 cache->cache_size = to_cblock(ca->cache_sectors >> cache->sectors_per_block_shift); 1945 cache->cache_size = to_cblock(ca->cache_sectors >> cache->sectors_per_block_shift);
1946 } 1946 }
1947 1947
1948 r = create_cache_policy(cache, ca, error); 1948 r = create_cache_policy(cache, ca, error);
1949 if (r) 1949 if (r)
1950 goto bad; 1950 goto bad;
1951 cache->policy_nr_args = ca->policy_argc; 1951 cache->policy_nr_args = ca->policy_argc;
1952 1952
1953 cmd = dm_cache_metadata_open(cache->metadata_dev->bdev, 1953 cmd = dm_cache_metadata_open(cache->metadata_dev->bdev,
1954 ca->block_size, may_format, 1954 ca->block_size, may_format,
1955 dm_cache_policy_get_hint_size(cache->policy)); 1955 dm_cache_policy_get_hint_size(cache->policy));
1956 if (IS_ERR(cmd)) { 1956 if (IS_ERR(cmd)) {
1957 *error = "Error creating metadata object"; 1957 *error = "Error creating metadata object";
1958 r = PTR_ERR(cmd); 1958 r = PTR_ERR(cmd);
1959 goto bad; 1959 goto bad;
1960 } 1960 }
1961 cache->cmd = cmd; 1961 cache->cmd = cmd;
1962 1962
1963 spin_lock_init(&cache->lock); 1963 spin_lock_init(&cache->lock);
1964 bio_list_init(&cache->deferred_bios); 1964 bio_list_init(&cache->deferred_bios);
1965 bio_list_init(&cache->deferred_flush_bios); 1965 bio_list_init(&cache->deferred_flush_bios);
1966 bio_list_init(&cache->deferred_writethrough_bios); 1966 bio_list_init(&cache->deferred_writethrough_bios);
1967 INIT_LIST_HEAD(&cache->quiesced_migrations); 1967 INIT_LIST_HEAD(&cache->quiesced_migrations);
1968 INIT_LIST_HEAD(&cache->completed_migrations); 1968 INIT_LIST_HEAD(&cache->completed_migrations);
1969 INIT_LIST_HEAD(&cache->need_commit_migrations); 1969 INIT_LIST_HEAD(&cache->need_commit_migrations);
1970 cache->migration_threshold = DEFAULT_MIGRATION_THRESHOLD; 1970 cache->migration_threshold = DEFAULT_MIGRATION_THRESHOLD;
1971 atomic_set(&cache->nr_migrations, 0); 1971 atomic_set(&cache->nr_migrations, 0);
1972 init_waitqueue_head(&cache->migration_wait); 1972 init_waitqueue_head(&cache->migration_wait);
1973 1973
1974 r = -ENOMEM;
1974 cache->nr_dirty = 0; 1975 cache->nr_dirty = 0;
1975 cache->dirty_bitset = alloc_bitset(from_cblock(cache->cache_size)); 1976 cache->dirty_bitset = alloc_bitset(from_cblock(cache->cache_size));
1976 if (!cache->dirty_bitset) { 1977 if (!cache->dirty_bitset) {
1977 *error = "could not allocate dirty bitset"; 1978 *error = "could not allocate dirty bitset";
1978 goto bad; 1979 goto bad;
1979 } 1980 }
1980 clear_bitset(cache->dirty_bitset, from_cblock(cache->cache_size)); 1981 clear_bitset(cache->dirty_bitset, from_cblock(cache->cache_size));
1981 1982
1982 cache->discard_block_size = 1983 cache->discard_block_size =
1983 calculate_discard_block_size(cache->sectors_per_block, 1984 calculate_discard_block_size(cache->sectors_per_block,
1984 cache->origin_sectors); 1985 cache->origin_sectors);
1985 cache->discard_nr_blocks = oblock_to_dblock(cache, cache->origin_blocks); 1986 cache->discard_nr_blocks = oblock_to_dblock(cache, cache->origin_blocks);
1986 cache->discard_bitset = alloc_bitset(from_dblock(cache->discard_nr_blocks)); 1987 cache->discard_bitset = alloc_bitset(from_dblock(cache->discard_nr_blocks));
1987 if (!cache->discard_bitset) { 1988 if (!cache->discard_bitset) {
1988 *error = "could not allocate discard bitset"; 1989 *error = "could not allocate discard bitset";
1989 goto bad; 1990 goto bad;
1990 } 1991 }
1991 clear_bitset(cache->discard_bitset, from_dblock(cache->discard_nr_blocks)); 1992 clear_bitset(cache->discard_bitset, from_dblock(cache->discard_nr_blocks));
1992 1993
1993 cache->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle); 1994 cache->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle);
1994 if (IS_ERR(cache->copier)) { 1995 if (IS_ERR(cache->copier)) {
1995 *error = "could not create kcopyd client"; 1996 *error = "could not create kcopyd client";
1996 r = PTR_ERR(cache->copier); 1997 r = PTR_ERR(cache->copier);
1997 goto bad; 1998 goto bad;
1998 } 1999 }
1999 2000
2000 cache->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM); 2001 cache->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
2001 if (!cache->wq) { 2002 if (!cache->wq) {
2002 *error = "could not create workqueue for metadata object"; 2003 *error = "could not create workqueue for metadata object";
2003 goto bad; 2004 goto bad;
2004 } 2005 }
2005 INIT_WORK(&cache->worker, do_worker); 2006 INIT_WORK(&cache->worker, do_worker);
2006 INIT_DELAYED_WORK(&cache->waker, do_waker); 2007 INIT_DELAYED_WORK(&cache->waker, do_waker);
2007 cache->last_commit_jiffies = jiffies; 2008 cache->last_commit_jiffies = jiffies;
2008 2009
2009 cache->prison = dm_bio_prison_create(PRISON_CELLS); 2010 cache->prison = dm_bio_prison_create(PRISON_CELLS);
2010 if (!cache->prison) { 2011 if (!cache->prison) {
2011 *error = "could not create bio prison"; 2012 *error = "could not create bio prison";
2012 goto bad; 2013 goto bad;
2013 } 2014 }
2014 2015
2015 cache->all_io_ds = dm_deferred_set_create(); 2016 cache->all_io_ds = dm_deferred_set_create();
2016 if (!cache->all_io_ds) { 2017 if (!cache->all_io_ds) {
2017 *error = "could not create all_io deferred set"; 2018 *error = "could not create all_io deferred set";
2018 goto bad; 2019 goto bad;
2019 } 2020 }
2020 2021
2021 cache->migration_pool = mempool_create_slab_pool(MIGRATION_POOL_SIZE, 2022 cache->migration_pool = mempool_create_slab_pool(MIGRATION_POOL_SIZE,
2022 migration_cache); 2023 migration_cache);
2023 if (!cache->migration_pool) { 2024 if (!cache->migration_pool) {
2024 *error = "Error creating cache's migration mempool"; 2025 *error = "Error creating cache's migration mempool";
2025 goto bad; 2026 goto bad;
2026 } 2027 }
2027 2028
2028 cache->next_migration = NULL; 2029 cache->next_migration = NULL;
2029 2030
2030 cache->need_tick_bio = true; 2031 cache->need_tick_bio = true;
2031 cache->sized = false; 2032 cache->sized = false;
2032 cache->quiescing = false; 2033 cache->quiescing = false;
2033 cache->commit_requested = false; 2034 cache->commit_requested = false;
2034 cache->loaded_mappings = false; 2035 cache->loaded_mappings = false;
2035 cache->loaded_discards = false; 2036 cache->loaded_discards = false;
2036 2037
2037 load_stats(cache); 2038 load_stats(cache);
2038 2039
2039 atomic_set(&cache->stats.demotion, 0); 2040 atomic_set(&cache->stats.demotion, 0);
2040 atomic_set(&cache->stats.promotion, 0); 2041 atomic_set(&cache->stats.promotion, 0);
2041 atomic_set(&cache->stats.copies_avoided, 0); 2042 atomic_set(&cache->stats.copies_avoided, 0);
2042 atomic_set(&cache->stats.cache_cell_clash, 0); 2043 atomic_set(&cache->stats.cache_cell_clash, 0);
2043 atomic_set(&cache->stats.commit_count, 0); 2044 atomic_set(&cache->stats.commit_count, 0);
2044 atomic_set(&cache->stats.discard_count, 0); 2045 atomic_set(&cache->stats.discard_count, 0);
2045 2046
2046 *result = cache; 2047 *result = cache;
2047 return 0; 2048 return 0;
2048 2049
2049 bad: 2050 bad:
2050 destroy(cache); 2051 destroy(cache);
2051 return r; 2052 return r;
2052 } 2053 }
2053 2054
2054 static int copy_ctr_args(struct cache *cache, int argc, const char **argv) 2055 static int copy_ctr_args(struct cache *cache, int argc, const char **argv)
2055 { 2056 {
2056 unsigned i; 2057 unsigned i;
2057 const char **copy; 2058 const char **copy;
2058 2059
2059 copy = kcalloc(argc, sizeof(*copy), GFP_KERNEL); 2060 copy = kcalloc(argc, sizeof(*copy), GFP_KERNEL);
2060 if (!copy) 2061 if (!copy)
2061 return -ENOMEM; 2062 return -ENOMEM;
2062 for (i = 0; i < argc; i++) { 2063 for (i = 0; i < argc; i++) {
2063 copy[i] = kstrdup(argv[i], GFP_KERNEL); 2064 copy[i] = kstrdup(argv[i], GFP_KERNEL);
2064 if (!copy[i]) { 2065 if (!copy[i]) {
2065 while (i--) 2066 while (i--)
2066 kfree(copy[i]); 2067 kfree(copy[i]);
2067 kfree(copy); 2068 kfree(copy);
2068 return -ENOMEM; 2069 return -ENOMEM;
2069 } 2070 }
2070 } 2071 }
2071 2072
2072 cache->nr_ctr_args = argc; 2073 cache->nr_ctr_args = argc;
2073 cache->ctr_args = copy; 2074 cache->ctr_args = copy;
2074 2075
2075 return 0; 2076 return 0;
2076 } 2077 }
2077 2078
2078 static int cache_ctr(struct dm_target *ti, unsigned argc, char **argv) 2079 static int cache_ctr(struct dm_target *ti, unsigned argc, char **argv)
2079 { 2080 {
2080 int r = -EINVAL; 2081 int r = -EINVAL;
2081 struct cache_args *ca; 2082 struct cache_args *ca;
2082 struct cache *cache = NULL; 2083 struct cache *cache = NULL;
2083 2084
2084 ca = kzalloc(sizeof(*ca), GFP_KERNEL); 2085 ca = kzalloc(sizeof(*ca), GFP_KERNEL);
2085 if (!ca) { 2086 if (!ca) {
2086 ti->error = "Error allocating memory for cache"; 2087 ti->error = "Error allocating memory for cache";
2087 return -ENOMEM; 2088 return -ENOMEM;
2088 } 2089 }
2089 ca->ti = ti; 2090 ca->ti = ti;
2090 2091
2091 r = parse_cache_args(ca, argc, argv, &ti->error); 2092 r = parse_cache_args(ca, argc, argv, &ti->error);
2092 if (r) 2093 if (r)
2093 goto out; 2094 goto out;
2094 2095
2095 r = cache_create(ca, &cache); 2096 r = cache_create(ca, &cache);
2096 if (r) 2097 if (r)
2097 goto out; 2098 goto out;
2098 2099
2099 r = copy_ctr_args(cache, argc - 3, (const char **)argv + 3); 2100 r = copy_ctr_args(cache, argc - 3, (const char **)argv + 3);
2100 if (r) { 2101 if (r) {
2101 destroy(cache); 2102 destroy(cache);
2102 goto out; 2103 goto out;
2103 } 2104 }
2104 2105
2105 ti->private = cache; 2106 ti->private = cache;
2106 2107
2107 out: 2108 out:
2108 destroy_cache_args(ca); 2109 destroy_cache_args(ca);
2109 return r; 2110 return r;
2110 } 2111 }
2111 2112
2112 static int cache_map(struct dm_target *ti, struct bio *bio) 2113 static int cache_map(struct dm_target *ti, struct bio *bio)
2113 { 2114 {
2114 struct cache *cache = ti->private; 2115 struct cache *cache = ti->private;
2115 2116
2116 int r; 2117 int r;
2117 dm_oblock_t block = get_bio_block(cache, bio); 2118 dm_oblock_t block = get_bio_block(cache, bio);
2118 size_t pb_data_size = get_per_bio_data_size(cache); 2119 size_t pb_data_size = get_per_bio_data_size(cache);
2119 bool can_migrate = false; 2120 bool can_migrate = false;
2120 bool discarded_block; 2121 bool discarded_block;
2121 struct dm_bio_prison_cell *cell; 2122 struct dm_bio_prison_cell *cell;
2122 struct policy_result lookup_result; 2123 struct policy_result lookup_result;
2123 struct per_bio_data *pb; 2124 struct per_bio_data *pb;
2124 2125
2125 if (from_oblock(block) > from_oblock(cache->origin_blocks)) { 2126 if (from_oblock(block) > from_oblock(cache->origin_blocks)) {
2126 /* 2127 /*
2127 * This can only occur if the io goes to a partial block at 2128 * This can only occur if the io goes to a partial block at
2128 * the end of the origin device. We don't cache these. 2129 * the end of the origin device. We don't cache these.
2129 * Just remap to the origin and carry on. 2130 * Just remap to the origin and carry on.
2130 */ 2131 */
2131 remap_to_origin_clear_discard(cache, bio, block); 2132 remap_to_origin_clear_discard(cache, bio, block);
2132 return DM_MAPIO_REMAPPED; 2133 return DM_MAPIO_REMAPPED;
2133 } 2134 }
2134 2135
2135 pb = init_per_bio_data(bio, pb_data_size); 2136 pb = init_per_bio_data(bio, pb_data_size);
2136 2137
2137 if (bio->bi_rw & (REQ_FLUSH | REQ_FUA | REQ_DISCARD)) { 2138 if (bio->bi_rw & (REQ_FLUSH | REQ_FUA | REQ_DISCARD)) {
2138 defer_bio(cache, bio); 2139 defer_bio(cache, bio);
2139 return DM_MAPIO_SUBMITTED; 2140 return DM_MAPIO_SUBMITTED;
2140 } 2141 }
2141 2142
2142 /* 2143 /*
2143 * Check to see if that block is currently migrating. 2144 * Check to see if that block is currently migrating.
2144 */ 2145 */
2145 cell = alloc_prison_cell(cache); 2146 cell = alloc_prison_cell(cache);
2146 if (!cell) { 2147 if (!cell) {
2147 defer_bio(cache, bio); 2148 defer_bio(cache, bio);
2148 return DM_MAPIO_SUBMITTED; 2149 return DM_MAPIO_SUBMITTED;
2149 } 2150 }
2150 2151
2151 r = bio_detain(cache, block, bio, cell, 2152 r = bio_detain(cache, block, bio, cell,
2152 (cell_free_fn) free_prison_cell, 2153 (cell_free_fn) free_prison_cell,
2153 cache, &cell); 2154 cache, &cell);
2154 if (r) { 2155 if (r) {
2155 if (r < 0) 2156 if (r < 0)
2156 defer_bio(cache, bio); 2157 defer_bio(cache, bio);
2157 2158
2158 return DM_MAPIO_SUBMITTED; 2159 return DM_MAPIO_SUBMITTED;
2159 } 2160 }
2160 2161
2161 discarded_block = is_discarded_oblock(cache, block); 2162 discarded_block = is_discarded_oblock(cache, block);
2162 2163
2163 r = policy_map(cache->policy, block, false, can_migrate, discarded_block, 2164 r = policy_map(cache->policy, block, false, can_migrate, discarded_block,
2164 bio, &lookup_result); 2165 bio, &lookup_result);
2165 if (r == -EWOULDBLOCK) { 2166 if (r == -EWOULDBLOCK) {
2166 cell_defer(cache, cell, true); 2167 cell_defer(cache, cell, true);
2167 return DM_MAPIO_SUBMITTED; 2168 return DM_MAPIO_SUBMITTED;
2168 2169
2169 } else if (r) { 2170 } else if (r) {
2170 DMERR_LIMIT("Unexpected return from cache replacement policy: %d", r); 2171 DMERR_LIMIT("Unexpected return from cache replacement policy: %d", r);
2171 bio_io_error(bio); 2172 bio_io_error(bio);
2172 return DM_MAPIO_SUBMITTED; 2173 return DM_MAPIO_SUBMITTED;
2173 } 2174 }
2174 2175
2175 switch (lookup_result.op) { 2176 switch (lookup_result.op) {
2176 case POLICY_HIT: 2177 case POLICY_HIT:
2177 inc_hit_counter(cache, bio); 2178 inc_hit_counter(cache, bio);
2178 pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); 2179 pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds);
2179 2180
2180 if (is_writethrough_io(cache, bio, lookup_result.cblock)) 2181 if (is_writethrough_io(cache, bio, lookup_result.cblock))
2181 remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock); 2182 remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock);
2182 else 2183 else
2183 remap_to_cache_dirty(cache, bio, block, lookup_result.cblock); 2184 remap_to_cache_dirty(cache, bio, block, lookup_result.cblock);
2184 2185
2185 cell_defer(cache, cell, false); 2186 cell_defer(cache, cell, false);
2186 break; 2187 break;
2187 2188
2188 case POLICY_MISS: 2189 case POLICY_MISS:
2189 inc_miss_counter(cache, bio); 2190 inc_miss_counter(cache, bio);
2190 pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); 2191 pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds);
2191 2192
2192 if (pb->req_nr != 0) { 2193 if (pb->req_nr != 0) {
2193 /* 2194 /*
2194 * This is a duplicate writethrough io that is no 2195 * This is a duplicate writethrough io that is no
2195 * longer needed because the block has been demoted. 2196 * longer needed because the block has been demoted.
2196 */ 2197 */
2197 bio_endio(bio, 0); 2198 bio_endio(bio, 0);
2198 cell_defer(cache, cell, false); 2199 cell_defer(cache, cell, false);
2199 return DM_MAPIO_SUBMITTED; 2200 return DM_MAPIO_SUBMITTED;
2200 } else { 2201 } else {
2201 remap_to_origin_clear_discard(cache, bio, block); 2202 remap_to_origin_clear_discard(cache, bio, block);
2202 cell_defer(cache, cell, false); 2203 cell_defer(cache, cell, false);
2203 } 2204 }
2204 break; 2205 break;
2205 2206
2206 default: 2207 default:
2207 DMERR_LIMIT("%s: erroring bio: unknown policy op: %u", __func__, 2208 DMERR_LIMIT("%s: erroring bio: unknown policy op: %u", __func__,
2208 (unsigned) lookup_result.op); 2209 (unsigned) lookup_result.op);
2209 bio_io_error(bio); 2210 bio_io_error(bio);
2210 return DM_MAPIO_SUBMITTED; 2211 return DM_MAPIO_SUBMITTED;
2211 } 2212 }
2212 2213
2213 return DM_MAPIO_REMAPPED; 2214 return DM_MAPIO_REMAPPED;
2214 } 2215 }
2215 2216
2216 static int cache_end_io(struct dm_target *ti, struct bio *bio, int error) 2217 static int cache_end_io(struct dm_target *ti, struct bio *bio, int error)
2217 { 2218 {
2218 struct cache *cache = ti->private; 2219 struct cache *cache = ti->private;
2219 unsigned long flags; 2220 unsigned long flags;
2220 size_t pb_data_size = get_per_bio_data_size(cache); 2221 size_t pb_data_size = get_per_bio_data_size(cache);
2221 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); 2222 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
2222 2223
2223 if (pb->tick) { 2224 if (pb->tick) {
2224 policy_tick(cache->policy); 2225 policy_tick(cache->policy);
2225 2226
2226 spin_lock_irqsave(&cache->lock, flags); 2227 spin_lock_irqsave(&cache->lock, flags);
2227 cache->need_tick_bio = true; 2228 cache->need_tick_bio = true;
2228 spin_unlock_irqrestore(&cache->lock, flags); 2229 spin_unlock_irqrestore(&cache->lock, flags);
2229 } 2230 }
2230 2231
2231 check_for_quiesced_migrations(cache, pb); 2232 check_for_quiesced_migrations(cache, pb);
2232 2233
2233 return 0; 2234 return 0;
2234 } 2235 }
2235 2236
2236 static int write_dirty_bitset(struct cache *cache) 2237 static int write_dirty_bitset(struct cache *cache)
2237 { 2238 {
2238 unsigned i, r; 2239 unsigned i, r;
2239 2240
2240 for (i = 0; i < from_cblock(cache->cache_size); i++) { 2241 for (i = 0; i < from_cblock(cache->cache_size); i++) {
2241 r = dm_cache_set_dirty(cache->cmd, to_cblock(i), 2242 r = dm_cache_set_dirty(cache->cmd, to_cblock(i),
2242 is_dirty(cache, to_cblock(i))); 2243 is_dirty(cache, to_cblock(i)));
2243 if (r) 2244 if (r)
2244 return r; 2245 return r;
2245 } 2246 }
2246 2247
2247 return 0; 2248 return 0;
2248 } 2249 }
2249 2250
2250 static int write_discard_bitset(struct cache *cache) 2251 static int write_discard_bitset(struct cache *cache)
2251 { 2252 {
2252 unsigned i, r; 2253 unsigned i, r;
2253 2254
2254 r = dm_cache_discard_bitset_resize(cache->cmd, cache->discard_block_size, 2255 r = dm_cache_discard_bitset_resize(cache->cmd, cache->discard_block_size,
2255 cache->discard_nr_blocks); 2256 cache->discard_nr_blocks);
2256 if (r) { 2257 if (r) {
2257 DMERR("could not resize on-disk discard bitset"); 2258 DMERR("could not resize on-disk discard bitset");
2258 return r; 2259 return r;
2259 } 2260 }
2260 2261
2261 for (i = 0; i < from_dblock(cache->discard_nr_blocks); i++) { 2262 for (i = 0; i < from_dblock(cache->discard_nr_blocks); i++) {
2262 r = dm_cache_set_discard(cache->cmd, to_dblock(i), 2263 r = dm_cache_set_discard(cache->cmd, to_dblock(i),
2263 is_discarded(cache, to_dblock(i))); 2264 is_discarded(cache, to_dblock(i)));
2264 if (r) 2265 if (r)
2265 return r; 2266 return r;
2266 } 2267 }
2267 2268
2268 return 0; 2269 return 0;
2269 } 2270 }
2270 2271
2271 static int save_hint(void *context, dm_cblock_t cblock, dm_oblock_t oblock, 2272 static int save_hint(void *context, dm_cblock_t cblock, dm_oblock_t oblock,
2272 uint32_t hint) 2273 uint32_t hint)
2273 { 2274 {
2274 struct cache *cache = context; 2275 struct cache *cache = context;
2275 return dm_cache_save_hint(cache->cmd, cblock, hint); 2276 return dm_cache_save_hint(cache->cmd, cblock, hint);
2276 } 2277 }
2277 2278
2278 static int write_hints(struct cache *cache) 2279 static int write_hints(struct cache *cache)
2279 { 2280 {
2280 int r; 2281 int r;
2281 2282
2282 r = dm_cache_begin_hints(cache->cmd, cache->policy); 2283 r = dm_cache_begin_hints(cache->cmd, cache->policy);
2283 if (r) { 2284 if (r) {
2284 DMERR("dm_cache_begin_hints failed"); 2285 DMERR("dm_cache_begin_hints failed");
2285 return r; 2286 return r;
2286 } 2287 }
2287 2288
2288 r = policy_walk_mappings(cache->policy, save_hint, cache); 2289 r = policy_walk_mappings(cache->policy, save_hint, cache);
2289 if (r) 2290 if (r)
2290 DMERR("policy_walk_mappings failed"); 2291 DMERR("policy_walk_mappings failed");
2291 2292
2292 return r; 2293 return r;
2293 } 2294 }
2294 2295
2295 /* 2296 /*
2296 * returns true on success 2297 * returns true on success
2297 */ 2298 */
2298 static bool sync_metadata(struct cache *cache) 2299 static bool sync_metadata(struct cache *cache)
2299 { 2300 {
2300 int r1, r2, r3, r4; 2301 int r1, r2, r3, r4;
2301 2302
2302 r1 = write_dirty_bitset(cache); 2303 r1 = write_dirty_bitset(cache);
2303 if (r1) 2304 if (r1)
2304 DMERR("could not write dirty bitset"); 2305 DMERR("could not write dirty bitset");
2305 2306
2306 r2 = write_discard_bitset(cache); 2307 r2 = write_discard_bitset(cache);
2307 if (r2) 2308 if (r2)
2308 DMERR("could not write discard bitset"); 2309 DMERR("could not write discard bitset");
2309 2310
2310 save_stats(cache); 2311 save_stats(cache);
2311 2312
2312 r3 = write_hints(cache); 2313 r3 = write_hints(cache);
2313 if (r3) 2314 if (r3)
2314 DMERR("could not write hints"); 2315 DMERR("could not write hints");
2315 2316
2316 /* 2317 /*
2317 * If writing the above metadata failed, we still commit, but don't 2318 * If writing the above metadata failed, we still commit, but don't
2318 * set the clean shutdown flag. This will effectively force every 2319 * set the clean shutdown flag. This will effectively force every
2319 * dirty bit to be set on reload. 2320 * dirty bit to be set on reload.
2320 */ 2321 */
2321 r4 = dm_cache_commit(cache->cmd, !r1 && !r2 && !r3); 2322 r4 = dm_cache_commit(cache->cmd, !r1 && !r2 && !r3);
2322 if (r4) 2323 if (r4)
2323 DMERR("could not write cache metadata. Data loss may occur."); 2324 DMERR("could not write cache metadata. Data loss may occur.");
2324 2325
2325 return !r1 && !r2 && !r3 && !r4; 2326 return !r1 && !r2 && !r3 && !r4;
2326 } 2327 }
2327 2328
2328 static void cache_postsuspend(struct dm_target *ti) 2329 static void cache_postsuspend(struct dm_target *ti)
2329 { 2330 {
2330 struct cache *cache = ti->private; 2331 struct cache *cache = ti->private;
2331 2332
2332 start_quiescing(cache); 2333 start_quiescing(cache);
2333 wait_for_migrations(cache); 2334 wait_for_migrations(cache);
2334 stop_worker(cache); 2335 stop_worker(cache);
2335 requeue_deferred_io(cache); 2336 requeue_deferred_io(cache);
2336 stop_quiescing(cache); 2337 stop_quiescing(cache);
2337 2338
2338 (void) sync_metadata(cache); 2339 (void) sync_metadata(cache);
2339 } 2340 }
2340 2341
2341 static int load_mapping(void *context, dm_oblock_t oblock, dm_cblock_t cblock, 2342 static int load_mapping(void *context, dm_oblock_t oblock, dm_cblock_t cblock,
2342 bool dirty, uint32_t hint, bool hint_valid) 2343 bool dirty, uint32_t hint, bool hint_valid)
2343 { 2344 {
2344 int r; 2345 int r;
2345 struct cache *cache = context; 2346 struct cache *cache = context;
2346 2347
2347 r = policy_load_mapping(cache->policy, oblock, cblock, hint, hint_valid); 2348 r = policy_load_mapping(cache->policy, oblock, cblock, hint, hint_valid);
2348 if (r) 2349 if (r)
2349 return r; 2350 return r;
2350 2351
2351 if (dirty) 2352 if (dirty)
2352 set_dirty(cache, oblock, cblock); 2353 set_dirty(cache, oblock, cblock);
2353 else 2354 else
2354 clear_dirty(cache, oblock, cblock); 2355 clear_dirty(cache, oblock, cblock);
2355 2356
2356 return 0; 2357 return 0;
2357 } 2358 }
2358 2359
2359 static int load_discard(void *context, sector_t discard_block_size, 2360 static int load_discard(void *context, sector_t discard_block_size,
2360 dm_dblock_t dblock, bool discard) 2361 dm_dblock_t dblock, bool discard)
2361 { 2362 {
2362 struct cache *cache = context; 2363 struct cache *cache = context;
2363 2364
2364 /* FIXME: handle mis-matched block size */ 2365 /* FIXME: handle mis-matched block size */
2365 2366
2366 if (discard) 2367 if (discard)
2367 set_discard(cache, dblock); 2368 set_discard(cache, dblock);
2368 else 2369 else
2369 clear_discard(cache, dblock); 2370 clear_discard(cache, dblock);
2370 2371
2371 return 0; 2372 return 0;
2372 } 2373 }
2373 2374
2374 static int cache_preresume(struct dm_target *ti) 2375 static int cache_preresume(struct dm_target *ti)
2375 { 2376 {
2376 int r = 0; 2377 int r = 0;
2377 struct cache *cache = ti->private; 2378 struct cache *cache = ti->private;
2378 sector_t actual_cache_size = get_dev_size(cache->cache_dev); 2379 sector_t actual_cache_size = get_dev_size(cache->cache_dev);
2379 (void) sector_div(actual_cache_size, cache->sectors_per_block); 2380 (void) sector_div(actual_cache_size, cache->sectors_per_block);
2380 2381
2381 /* 2382 /*
2382 * Check to see if the cache has resized. 2383 * Check to see if the cache has resized.
2383 */ 2384 */
2384 if (from_cblock(cache->cache_size) != actual_cache_size || !cache->sized) { 2385 if (from_cblock(cache->cache_size) != actual_cache_size || !cache->sized) {
2385 cache->cache_size = to_cblock(actual_cache_size); 2386 cache->cache_size = to_cblock(actual_cache_size);
2386 2387
2387 r = dm_cache_resize(cache->cmd, cache->cache_size); 2388 r = dm_cache_resize(cache->cmd, cache->cache_size);
2388 if (r) { 2389 if (r) {
2389 DMERR("could not resize cache metadata"); 2390 DMERR("could not resize cache metadata");
2390 return r; 2391 return r;
2391 } 2392 }
2392 2393
2393 cache->sized = true; 2394 cache->sized = true;
2394 } 2395 }
2395 2396
2396 if (!cache->loaded_mappings) { 2397 if (!cache->loaded_mappings) {
2397 r = dm_cache_load_mappings(cache->cmd, cache->policy, 2398 r = dm_cache_load_mappings(cache->cmd, cache->policy,
2398 load_mapping, cache); 2399 load_mapping, cache);
2399 if (r) { 2400 if (r) {
2400 DMERR("could not load cache mappings"); 2401 DMERR("could not load cache mappings");
2401 return r; 2402 return r;
2402 } 2403 }
2403 2404
2404 cache->loaded_mappings = true; 2405 cache->loaded_mappings = true;
2405 } 2406 }
2406 2407
2407 if (!cache->loaded_discards) { 2408 if (!cache->loaded_discards) {
2408 r = dm_cache_load_discards(cache->cmd, load_discard, cache); 2409 r = dm_cache_load_discards(cache->cmd, load_discard, cache);
2409 if (r) { 2410 if (r) {
2410 DMERR("could not load origin discards"); 2411 DMERR("could not load origin discards");
2411 return r; 2412 return r;
2412 } 2413 }
2413 2414
2414 cache->loaded_discards = true; 2415 cache->loaded_discards = true;
2415 } 2416 }
2416 2417
2417 return r; 2418 return r;
2418 } 2419 }
2419 2420
2420 static void cache_resume(struct dm_target *ti) 2421 static void cache_resume(struct dm_target *ti)
2421 { 2422 {
2422 struct cache *cache = ti->private; 2423 struct cache *cache = ti->private;
2423 2424
2424 cache->need_tick_bio = true; 2425 cache->need_tick_bio = true;
2425 do_waker(&cache->waker.work); 2426 do_waker(&cache->waker.work);
2426 } 2427 }
2427 2428
2428 /* 2429 /*
2429 * Status format: 2430 * Status format:
2430 * 2431 *
2431 * <#used metadata blocks>/<#total metadata blocks> 2432 * <#used metadata blocks>/<#total metadata blocks>
2432 * <#read hits> <#read misses> <#write hits> <#write misses> 2433 * <#read hits> <#read misses> <#write hits> <#write misses>
2433 * <#demotions> <#promotions> <#blocks in cache> <#dirty> 2434 * <#demotions> <#promotions> <#blocks in cache> <#dirty>
2434 * <#features> <features>* 2435 * <#features> <features>*
2435 * <#core args> <core args> 2436 * <#core args> <core args>
2436 * <#policy args> <policy args>* 2437 * <#policy args> <policy args>*
2437 */ 2438 */
2438 static void cache_status(struct dm_target *ti, status_type_t type, 2439 static void cache_status(struct dm_target *ti, status_type_t type,
2439 unsigned status_flags, char *result, unsigned maxlen) 2440 unsigned status_flags, char *result, unsigned maxlen)
2440 { 2441 {
2441 int r = 0; 2442 int r = 0;
2442 unsigned i; 2443 unsigned i;
2443 ssize_t sz = 0; 2444 ssize_t sz = 0;
2444 dm_block_t nr_free_blocks_metadata = 0; 2445 dm_block_t nr_free_blocks_metadata = 0;
2445 dm_block_t nr_blocks_metadata = 0; 2446 dm_block_t nr_blocks_metadata = 0;
2446 char buf[BDEVNAME_SIZE]; 2447 char buf[BDEVNAME_SIZE];
2447 struct cache *cache = ti->private; 2448 struct cache *cache = ti->private;
2448 dm_cblock_t residency; 2449 dm_cblock_t residency;
2449 2450
2450 switch (type) { 2451 switch (type) {
2451 case STATUSTYPE_INFO: 2452 case STATUSTYPE_INFO:
2452 /* Commit to ensure statistics aren't out-of-date */ 2453 /* Commit to ensure statistics aren't out-of-date */
2453 if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti)) { 2454 if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti)) {
2454 r = dm_cache_commit(cache->cmd, false); 2455 r = dm_cache_commit(cache->cmd, false);
2455 if (r) 2456 if (r)
2456 DMERR("could not commit metadata for accurate status"); 2457 DMERR("could not commit metadata for accurate status");
2457 } 2458 }
2458 2459
2459 r = dm_cache_get_free_metadata_block_count(cache->cmd, 2460 r = dm_cache_get_free_metadata_block_count(cache->cmd,
2460 &nr_free_blocks_metadata); 2461 &nr_free_blocks_metadata);
2461 if (r) { 2462 if (r) {
2462 DMERR("could not get metadata free block count"); 2463 DMERR("could not get metadata free block count");
2463 goto err; 2464 goto err;
2464 } 2465 }
2465 2466
2466 r = dm_cache_get_metadata_dev_size(cache->cmd, &nr_blocks_metadata); 2467 r = dm_cache_get_metadata_dev_size(cache->cmd, &nr_blocks_metadata);
2467 if (r) { 2468 if (r) {
2468 DMERR("could not get metadata device size"); 2469 DMERR("could not get metadata device size");
2469 goto err; 2470 goto err;
2470 } 2471 }
2471 2472
2472 residency = policy_residency(cache->policy); 2473 residency = policy_residency(cache->policy);
2473 2474
2474 DMEMIT("%llu/%llu %u %u %u %u %u %u %llu %u ", 2475 DMEMIT("%llu/%llu %u %u %u %u %u %u %llu %u ",
2475 (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata), 2476 (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata),
2476 (unsigned long long)nr_blocks_metadata, 2477 (unsigned long long)nr_blocks_metadata,
2477 (unsigned) atomic_read(&cache->stats.read_hit), 2478 (unsigned) atomic_read(&cache->stats.read_hit),
2478 (unsigned) atomic_read(&cache->stats.read_miss), 2479 (unsigned) atomic_read(&cache->stats.read_miss),
2479 (unsigned) atomic_read(&cache->stats.write_hit), 2480 (unsigned) atomic_read(&cache->stats.write_hit),
2480 (unsigned) atomic_read(&cache->stats.write_miss), 2481 (unsigned) atomic_read(&cache->stats.write_miss),
2481 (unsigned) atomic_read(&cache->stats.demotion), 2482 (unsigned) atomic_read(&cache->stats.demotion),
2482 (unsigned) atomic_read(&cache->stats.promotion), 2483 (unsigned) atomic_read(&cache->stats.promotion),
2483 (unsigned long long) from_cblock(residency), 2484 (unsigned long long) from_cblock(residency),
2484 cache->nr_dirty); 2485 cache->nr_dirty);
2485 2486
2486 if (cache->features.write_through) 2487 if (cache->features.write_through)
2487 DMEMIT("1 writethrough "); 2488 DMEMIT("1 writethrough ");
2488 else 2489 else
2489 DMEMIT("0 "); 2490 DMEMIT("0 ");
2490 2491
2491 DMEMIT("2 migration_threshold %llu ", (unsigned long long) cache->migration_threshold); 2492 DMEMIT("2 migration_threshold %llu ", (unsigned long long) cache->migration_threshold);
2492 if (sz < maxlen) { 2493 if (sz < maxlen) {
2493 r = policy_emit_config_values(cache->policy, result + sz, maxlen - sz); 2494 r = policy_emit_config_values(cache->policy, result + sz, maxlen - sz);
2494 if (r) 2495 if (r)
2495 DMERR("policy_emit_config_values returned %d", r); 2496 DMERR("policy_emit_config_values returned %d", r);
2496 } 2497 }
2497 2498
2498 break; 2499 break;
2499 2500
2500 case STATUSTYPE_TABLE: 2501 case STATUSTYPE_TABLE:
2501 format_dev_t(buf, cache->metadata_dev->bdev->bd_dev); 2502 format_dev_t(buf, cache->metadata_dev->bdev->bd_dev);
2502 DMEMIT("%s ", buf); 2503 DMEMIT("%s ", buf);
2503 format_dev_t(buf, cache->cache_dev->bdev->bd_dev); 2504 format_dev_t(buf, cache->cache_dev->bdev->bd_dev);
2504 DMEMIT("%s ", buf); 2505 DMEMIT("%s ", buf);
2505 format_dev_t(buf, cache->origin_dev->bdev->bd_dev); 2506 format_dev_t(buf, cache->origin_dev->bdev->bd_dev);
2506 DMEMIT("%s", buf); 2507 DMEMIT("%s", buf);
2507 2508
2508 for (i = 0; i < cache->nr_ctr_args - 1; i++) 2509 for (i = 0; i < cache->nr_ctr_args - 1; i++)
2509 DMEMIT(" %s", cache->ctr_args[i]); 2510 DMEMIT(" %s", cache->ctr_args[i]);
2510 if (cache->nr_ctr_args) 2511 if (cache->nr_ctr_args)
2511 DMEMIT(" %s", cache->ctr_args[cache->nr_ctr_args - 1]); 2512 DMEMIT(" %s", cache->ctr_args[cache->nr_ctr_args - 1]);
2512 } 2513 }
2513 2514
2514 return; 2515 return;
2515 2516
2516 err: 2517 err:
2517 DMEMIT("Error"); 2518 DMEMIT("Error");
2518 } 2519 }
2519 2520
2520 #define NOT_CORE_OPTION 1 2521 #define NOT_CORE_OPTION 1
2521 2522
2522 static int process_config_option(struct cache *cache, char **argv) 2523 static int process_config_option(struct cache *cache, char **argv)
2523 { 2524 {
2524 unsigned long tmp; 2525 unsigned long tmp;
2525 2526
2526 if (!strcasecmp(argv[0], "migration_threshold")) { 2527 if (!strcasecmp(argv[0], "migration_threshold")) {
2527 if (kstrtoul(argv[1], 10, &tmp)) 2528 if (kstrtoul(argv[1], 10, &tmp))
2528 return -EINVAL; 2529 return -EINVAL;
2529 2530
2530 cache->migration_threshold = tmp; 2531 cache->migration_threshold = tmp;
2531 return 0; 2532 return 0;
2532 } 2533 }
2533 2534
2534 return NOT_CORE_OPTION; 2535 return NOT_CORE_OPTION;
2535 } 2536 }
2536 2537
2537 /* 2538 /*
2538 * Supports <key> <value>. 2539 * Supports <key> <value>.
2539 * 2540 *
2540 * The key migration_threshold is supported by the cache target core. 2541 * The key migration_threshold is supported by the cache target core.
2541 */ 2542 */
2542 static int cache_message(struct dm_target *ti, unsigned argc, char **argv) 2543 static int cache_message(struct dm_target *ti, unsigned argc, char **argv)
2543 { 2544 {
2544 int r; 2545 int r;
2545 struct cache *cache = ti->private; 2546 struct cache *cache = ti->private;
2546 2547
2547 if (argc != 2) 2548 if (argc != 2)
2548 return -EINVAL; 2549 return -EINVAL;
2549 2550
2550 r = process_config_option(cache, argv); 2551 r = process_config_option(cache, argv);
2551 if (r == NOT_CORE_OPTION) 2552 if (r == NOT_CORE_OPTION)
2552 return policy_set_config_value(cache->policy, argv[0], argv[1]); 2553 return policy_set_config_value(cache->policy, argv[0], argv[1]);
2553 2554
2554 return r; 2555 return r;
2555 } 2556 }
2556 2557
2557 static int cache_iterate_devices(struct dm_target *ti, 2558 static int cache_iterate_devices(struct dm_target *ti,
2558 iterate_devices_callout_fn fn, void *data) 2559 iterate_devices_callout_fn fn, void *data)
2559 { 2560 {
2560 int r = 0; 2561 int r = 0;
2561 struct cache *cache = ti->private; 2562 struct cache *cache = ti->private;
2562 2563
2563 r = fn(ti, cache->cache_dev, 0, get_dev_size(cache->cache_dev), data); 2564 r = fn(ti, cache->cache_dev, 0, get_dev_size(cache->cache_dev), data);
2564 if (!r) 2565 if (!r)
2565 r = fn(ti, cache->origin_dev, 0, ti->len, data); 2566 r = fn(ti, cache->origin_dev, 0, ti->len, data);
2566 2567
2567 return r; 2568 return r;
2568 } 2569 }
2569 2570
2570 /* 2571 /*
2571 * We assume I/O is going to the origin (which is the volume 2572 * We assume I/O is going to the origin (which is the volume
2572 * more likely to have restrictions e.g. by being striped). 2573 * more likely to have restrictions e.g. by being striped).
2573 * (Looking up the exact location of the data would be expensive 2574 * (Looking up the exact location of the data would be expensive
2574 * and could always be out of date by the time the bio is submitted.) 2575 * and could always be out of date by the time the bio is submitted.)
2575 */ 2576 */
2576 static int cache_bvec_merge(struct dm_target *ti, 2577 static int cache_bvec_merge(struct dm_target *ti,
2577 struct bvec_merge_data *bvm, 2578 struct bvec_merge_data *bvm,
2578 struct bio_vec *biovec, int max_size) 2579 struct bio_vec *biovec, int max_size)
2579 { 2580 {
2580 struct cache *cache = ti->private; 2581 struct cache *cache = ti->private;
2581 struct request_queue *q = bdev_get_queue(cache->origin_dev->bdev); 2582 struct request_queue *q = bdev_get_queue(cache->origin_dev->bdev);
2582 2583
2583 if (!q->merge_bvec_fn) 2584 if (!q->merge_bvec_fn)
2584 return max_size; 2585 return max_size;
2585 2586
2586 bvm->bi_bdev = cache->origin_dev->bdev; 2587 bvm->bi_bdev = cache->origin_dev->bdev;
2587 return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); 2588 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
2588 } 2589 }
2589 2590
2590 static void set_discard_limits(struct cache *cache, struct queue_limits *limits) 2591 static void set_discard_limits(struct cache *cache, struct queue_limits *limits)
2591 { 2592 {
2592 /* 2593 /*
2593 * FIXME: these limits may be incompatible with the cache device 2594 * FIXME: these limits may be incompatible with the cache device
2594 */ 2595 */
2595 limits->max_discard_sectors = cache->discard_block_size * 1024; 2596 limits->max_discard_sectors = cache->discard_block_size * 1024;
2596 limits->discard_granularity = cache->discard_block_size << SECTOR_SHIFT; 2597 limits->discard_granularity = cache->discard_block_size << SECTOR_SHIFT;
2597 } 2598 }
2598 2599
2599 static void cache_io_hints(struct dm_target *ti, struct queue_limits *limits) 2600 static void cache_io_hints(struct dm_target *ti, struct queue_limits *limits)
2600 { 2601 {
2601 struct cache *cache = ti->private; 2602 struct cache *cache = ti->private;
2602 2603
2603 blk_limits_io_min(limits, 0); 2604 blk_limits_io_min(limits, 0);
2604 blk_limits_io_opt(limits, cache->sectors_per_block << SECTOR_SHIFT); 2605 blk_limits_io_opt(limits, cache->sectors_per_block << SECTOR_SHIFT);
2605 set_discard_limits(cache, limits); 2606 set_discard_limits(cache, limits);
2606 } 2607 }
2607 2608
2608 /*----------------------------------------------------------------*/ 2609 /*----------------------------------------------------------------*/
2609 2610
2610 static struct target_type cache_target = { 2611 static struct target_type cache_target = {
2611 .name = "cache", 2612 .name = "cache",
2612 .version = {1, 1, 0}, 2613 .version = {1, 1, 0},
2613 .module = THIS_MODULE, 2614 .module = THIS_MODULE,
2614 .ctr = cache_ctr, 2615 .ctr = cache_ctr,
2615 .dtr = cache_dtr, 2616 .dtr = cache_dtr,
2616 .map = cache_map, 2617 .map = cache_map,
2617 .end_io = cache_end_io, 2618 .end_io = cache_end_io,
2618 .postsuspend = cache_postsuspend, 2619 .postsuspend = cache_postsuspend,
2619 .preresume = cache_preresume, 2620 .preresume = cache_preresume,
2620 .resume = cache_resume, 2621 .resume = cache_resume,
2621 .status = cache_status, 2622 .status = cache_status,
2622 .message = cache_message, 2623 .message = cache_message,
2623 .iterate_devices = cache_iterate_devices, 2624 .iterate_devices = cache_iterate_devices,
2624 .merge = cache_bvec_merge, 2625 .merge = cache_bvec_merge,
2625 .io_hints = cache_io_hints, 2626 .io_hints = cache_io_hints,
2626 }; 2627 };
2627 2628
2628 static int __init dm_cache_init(void) 2629 static int __init dm_cache_init(void)
2629 { 2630 {
2630 int r; 2631 int r;
2631 2632
2632 r = dm_register_target(&cache_target); 2633 r = dm_register_target(&cache_target);
2633 if (r) { 2634 if (r) {
2634 DMERR("cache target registration failed: %d", r); 2635 DMERR("cache target registration failed: %d", r);
2635 return r; 2636 return r;
2636 } 2637 }
2637 2638
2638 migration_cache = KMEM_CACHE(dm_cache_migration, 0); 2639 migration_cache = KMEM_CACHE(dm_cache_migration, 0);
2639 if (!migration_cache) { 2640 if (!migration_cache) {
2640 dm_unregister_target(&cache_target); 2641 dm_unregister_target(&cache_target);
2641 return -ENOMEM; 2642 return -ENOMEM;
2642 } 2643 }
2643 2644
2644 return 0; 2645 return 0;
2645 } 2646 }
2646 2647
2647 static void __exit dm_cache_exit(void) 2648 static void __exit dm_cache_exit(void)
2648 { 2649 {
2649 dm_unregister_target(&cache_target); 2650 dm_unregister_target(&cache_target);
2650 kmem_cache_destroy(migration_cache); 2651 kmem_cache_destroy(migration_cache);
2651 } 2652 }
2652 2653
2653 module_init(dm_cache_init); 2654 module_init(dm_cache_init);
2654 module_exit(dm_cache_exit); 2655 module_exit(dm_cache_exit);
2655 2656
2656 MODULE_DESCRIPTION(DM_NAME " cache target"); 2657 MODULE_DESCRIPTION(DM_NAME " cache target");
2657 MODULE_AUTHOR("Joe Thornber <ejt@redhat.com>"); 2658 MODULE_AUTHOR("Joe Thornber <ejt@redhat.com>");
2658 MODULE_LICENSE("GPL"); 2659 MODULE_LICENSE("GPL");
2659 2660