diff options
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/md/Kconfig | 13 | ||||
-rw-r--r-- | drivers/md/Makefile | 2 | ||||
-rw-r--r-- | drivers/md/dm-bio-prison.c | 9 | ||||
-rw-r--r-- | drivers/md/dm-bio-prison.h | 11 | ||||
-rw-r--r-- | drivers/md/dm-cache-block-types.h | 54 | ||||
-rw-r--r-- | drivers/md/dm-cache-metadata.c | 1146 | ||||
-rw-r--r-- | drivers/md/dm-cache-metadata.h | 142 | ||||
-rw-r--r-- | drivers/md/dm-cache-policy-internal.h | 124 | ||||
-rw-r--r-- | drivers/md/dm-cache-policy.c | 161 | ||||
-rw-r--r-- | drivers/md/dm-cache-policy.h | 228 | ||||
-rw-r--r-- | drivers/md/dm-cache-target.c | 2584 | ||||
-rw-r--r-- | drivers/md/persistent-data/dm-block-manager.c | 1 |
12 files changed, 4475 insertions, 0 deletions
diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig index 7cdf359d6b23..1a4fbcdb5ca2 100644 --- a/drivers/md/Kconfig +++ b/drivers/md/Kconfig | |||
@@ -268,6 +268,19 @@ config DM_DEBUG_BLOCK_STACK_TRACING | |||
268 | 268 | ||
269 | If unsure, say N. | 269 | If unsure, say N. |
270 | 270 | ||
271 | config DM_CACHE | ||
272 | tristate "Cache target (EXPERIMENTAL)" | ||
273 | depends on BLK_DEV_DM | ||
274 | default n | ||
275 | select DM_PERSISTENT_DATA | ||
276 | select DM_BIO_PRISON | ||
277 | ---help--- | ||
278 | dm-cache attempts to improve performance of a block device by | ||
279 | moving frequently used data to a smaller, higher performance | ||
280 | device. Different 'policy' plugins can be used to change the | ||
281 | algorithms used to select which blocks are promoted, demoted, | ||
282 | cleaned etc. It supports writeback and writethrough modes. | ||
283 | |||
271 | config DM_MIRROR | 284 | config DM_MIRROR |
272 | tristate "Mirror target" | 285 | tristate "Mirror target" |
273 | depends on BLK_DEV_DM | 286 | depends on BLK_DEV_DM |
diff --git a/drivers/md/Makefile b/drivers/md/Makefile index 94dce8b49324..24b52560f4d2 100644 --- a/drivers/md/Makefile +++ b/drivers/md/Makefile | |||
@@ -11,6 +11,7 @@ dm-mirror-y += dm-raid1.o | |||
11 | dm-log-userspace-y \ | 11 | dm-log-userspace-y \ |
12 | += dm-log-userspace-base.o dm-log-userspace-transfer.o | 12 | += dm-log-userspace-base.o dm-log-userspace-transfer.o |
13 | dm-thin-pool-y += dm-thin.o dm-thin-metadata.o | 13 | dm-thin-pool-y += dm-thin.o dm-thin-metadata.o |
14 | dm-cache-y += dm-cache-target.o dm-cache-metadata.o dm-cache-policy.o | ||
14 | md-mod-y += md.o bitmap.o | 15 | md-mod-y += md.o bitmap.o |
15 | raid456-y += raid5.o | 16 | raid456-y += raid5.o |
16 | 17 | ||
@@ -44,6 +45,7 @@ obj-$(CONFIG_DM_ZERO) += dm-zero.o | |||
44 | obj-$(CONFIG_DM_RAID) += dm-raid.o | 45 | obj-$(CONFIG_DM_RAID) += dm-raid.o |
45 | obj-$(CONFIG_DM_THIN_PROVISIONING) += dm-thin-pool.o | 46 | obj-$(CONFIG_DM_THIN_PROVISIONING) += dm-thin-pool.o |
46 | obj-$(CONFIG_DM_VERITY) += dm-verity.o | 47 | obj-$(CONFIG_DM_VERITY) += dm-verity.o |
48 | obj-$(CONFIG_DM_CACHE) += dm-cache.o | ||
47 | 49 | ||
48 | ifeq ($(CONFIG_DM_UEVENT),y) | 50 | ifeq ($(CONFIG_DM_UEVENT),y) |
49 | dm-mod-objs += dm-uevent.o | 51 | dm-mod-objs += dm-uevent.o |
diff --git a/drivers/md/dm-bio-prison.c b/drivers/md/dm-bio-prison.c index 144067c95aba..85f0b7074257 100644 --- a/drivers/md/dm-bio-prison.c +++ b/drivers/md/dm-bio-prison.c | |||
@@ -179,6 +179,15 @@ int dm_bio_detain(struct dm_bio_prison *prison, | |||
179 | } | 179 | } |
180 | EXPORT_SYMBOL_GPL(dm_bio_detain); | 180 | EXPORT_SYMBOL_GPL(dm_bio_detain); |
181 | 181 | ||
182 | int dm_get_cell(struct dm_bio_prison *prison, | ||
183 | struct dm_cell_key *key, | ||
184 | struct dm_bio_prison_cell *cell_prealloc, | ||
185 | struct dm_bio_prison_cell **cell_result) | ||
186 | { | ||
187 | return bio_detain(prison, key, NULL, cell_prealloc, cell_result); | ||
188 | } | ||
189 | EXPORT_SYMBOL_GPL(dm_get_cell); | ||
190 | |||
182 | /* | 191 | /* |
183 | * @inmates must have been initialised prior to this call | 192 | * @inmates must have been initialised prior to this call |
184 | */ | 193 | */ |
diff --git a/drivers/md/dm-bio-prison.h b/drivers/md/dm-bio-prison.h index 981a02d3a055..3f833190eadf 100644 --- a/drivers/md/dm-bio-prison.h +++ b/drivers/md/dm-bio-prison.h | |||
@@ -57,6 +57,17 @@ void dm_bio_prison_free_cell(struct dm_bio_prison *prison, | |||
57 | struct dm_bio_prison_cell *cell); | 57 | struct dm_bio_prison_cell *cell); |
58 | 58 | ||
59 | /* | 59 | /* |
60 | * Creates, or retrieves a cell for the given key. | ||
61 | * | ||
62 | * Returns 1 if pre-existing cell returned, zero if new cell created using | ||
63 | * @cell_prealloc. | ||
64 | */ | ||
65 | int dm_get_cell(struct dm_bio_prison *prison, | ||
66 | struct dm_cell_key *key, | ||
67 | struct dm_bio_prison_cell *cell_prealloc, | ||
68 | struct dm_bio_prison_cell **cell_result); | ||
69 | |||
70 | /* | ||
60 | * An atomic op that combines retrieving a cell, and adding a bio to it. | 71 | * An atomic op that combines retrieving a cell, and adding a bio to it. |
61 | * | 72 | * |
62 | * Returns 1 if the cell was already held, 0 if @inmate is the new holder. | 73 | * Returns 1 if the cell was already held, 0 if @inmate is the new holder. |
diff --git a/drivers/md/dm-cache-block-types.h b/drivers/md/dm-cache-block-types.h new file mode 100644 index 000000000000..bed4ad4e1b7c --- /dev/null +++ b/drivers/md/dm-cache-block-types.h | |||
@@ -0,0 +1,54 @@ | |||
1 | /* | ||
2 | * Copyright (C) 2012 Red Hat, Inc. | ||
3 | * | ||
4 | * This file is released under the GPL. | ||
5 | */ | ||
6 | |||
7 | #ifndef DM_CACHE_BLOCK_TYPES_H | ||
8 | #define DM_CACHE_BLOCK_TYPES_H | ||
9 | |||
10 | #include "persistent-data/dm-block-manager.h" | ||
11 | |||
12 | /*----------------------------------------------------------------*/ | ||
13 | |||
14 | /* | ||
15 | * It's helpful to get sparse to differentiate between indexes into the | ||
16 | * origin device, indexes into the cache device, and indexes into the | ||
17 | * discard bitset. | ||
18 | */ | ||
19 | |||
20 | typedef dm_block_t __bitwise__ dm_oblock_t; | ||
21 | typedef uint32_t __bitwise__ dm_cblock_t; | ||
22 | typedef dm_block_t __bitwise__ dm_dblock_t; | ||
23 | |||
24 | static inline dm_oblock_t to_oblock(dm_block_t b) | ||
25 | { | ||
26 | return (__force dm_oblock_t) b; | ||
27 | } | ||
28 | |||
29 | static inline dm_block_t from_oblock(dm_oblock_t b) | ||
30 | { | ||
31 | return (__force dm_block_t) b; | ||
32 | } | ||
33 | |||
34 | static inline dm_cblock_t to_cblock(uint32_t b) | ||
35 | { | ||
36 | return (__force dm_cblock_t) b; | ||
37 | } | ||
38 | |||
39 | static inline uint32_t from_cblock(dm_cblock_t b) | ||
40 | { | ||
41 | return (__force uint32_t) b; | ||
42 | } | ||
43 | |||
44 | static inline dm_dblock_t to_dblock(dm_block_t b) | ||
45 | { | ||
46 | return (__force dm_dblock_t) b; | ||
47 | } | ||
48 | |||
49 | static inline dm_block_t from_dblock(dm_dblock_t b) | ||
50 | { | ||
51 | return (__force dm_block_t) b; | ||
52 | } | ||
53 | |||
54 | #endif /* DM_CACHE_BLOCK_TYPES_H */ | ||
diff --git a/drivers/md/dm-cache-metadata.c b/drivers/md/dm-cache-metadata.c new file mode 100644 index 000000000000..fbd3625f2748 --- /dev/null +++ b/drivers/md/dm-cache-metadata.c | |||
@@ -0,0 +1,1146 @@ | |||
1 | /* | ||
2 | * Copyright (C) 2012 Red Hat, Inc. | ||
3 | * | ||
4 | * This file is released under the GPL. | ||
5 | */ | ||
6 | |||
7 | #include "dm-cache-metadata.h" | ||
8 | |||
9 | #include "persistent-data/dm-array.h" | ||
10 | #include "persistent-data/dm-bitset.h" | ||
11 | #include "persistent-data/dm-space-map.h" | ||
12 | #include "persistent-data/dm-space-map-disk.h" | ||
13 | #include "persistent-data/dm-transaction-manager.h" | ||
14 | |||
15 | #include <linux/device-mapper.h> | ||
16 | |||
17 | /*----------------------------------------------------------------*/ | ||
18 | |||
19 | #define DM_MSG_PREFIX "cache metadata" | ||
20 | |||
21 | #define CACHE_SUPERBLOCK_MAGIC 06142003 | ||
22 | #define CACHE_SUPERBLOCK_LOCATION 0 | ||
23 | #define CACHE_VERSION 1 | ||
24 | #define CACHE_METADATA_CACHE_SIZE 64 | ||
25 | |||
26 | /* | ||
27 | * 3 for btree insert + | ||
28 | * 2 for btree lookup used within space map | ||
29 | */ | ||
30 | #define CACHE_MAX_CONCURRENT_LOCKS 5 | ||
31 | #define SPACE_MAP_ROOT_SIZE 128 | ||
32 | |||
33 | enum superblock_flag_bits { | ||
34 | /* for spotting crashes that would invalidate the dirty bitset */ | ||
35 | CLEAN_SHUTDOWN, | ||
36 | }; | ||
37 | |||
38 | /* | ||
39 | * Each mapping from cache block -> origin block carries a set of flags. | ||
40 | */ | ||
41 | enum mapping_bits { | ||
42 | /* | ||
43 | * A valid mapping. Because we're using an array we clear this | ||
44 | * flag for an non existant mapping. | ||
45 | */ | ||
46 | M_VALID = 1, | ||
47 | |||
48 | /* | ||
49 | * The data on the cache is different from that on the origin. | ||
50 | */ | ||
51 | M_DIRTY = 2 | ||
52 | }; | ||
53 | |||
54 | struct cache_disk_superblock { | ||
55 | __le32 csum; | ||
56 | __le32 flags; | ||
57 | __le64 blocknr; | ||
58 | |||
59 | __u8 uuid[16]; | ||
60 | __le64 magic; | ||
61 | __le32 version; | ||
62 | |||
63 | __u8 policy_name[CACHE_POLICY_NAME_SIZE]; | ||
64 | __le32 policy_hint_size; | ||
65 | |||
66 | __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE]; | ||
67 | __le64 mapping_root; | ||
68 | __le64 hint_root; | ||
69 | |||
70 | __le64 discard_root; | ||
71 | __le64 discard_block_size; | ||
72 | __le64 discard_nr_blocks; | ||
73 | |||
74 | __le32 data_block_size; | ||
75 | __le32 metadata_block_size; | ||
76 | __le32 cache_blocks; | ||
77 | |||
78 | __le32 compat_flags; | ||
79 | __le32 compat_ro_flags; | ||
80 | __le32 incompat_flags; | ||
81 | |||
82 | __le32 read_hits; | ||
83 | __le32 read_misses; | ||
84 | __le32 write_hits; | ||
85 | __le32 write_misses; | ||
86 | } __packed; | ||
87 | |||
88 | struct dm_cache_metadata { | ||
89 | struct block_device *bdev; | ||
90 | struct dm_block_manager *bm; | ||
91 | struct dm_space_map *metadata_sm; | ||
92 | struct dm_transaction_manager *tm; | ||
93 | |||
94 | struct dm_array_info info; | ||
95 | struct dm_array_info hint_info; | ||
96 | struct dm_disk_bitset discard_info; | ||
97 | |||
98 | struct rw_semaphore root_lock; | ||
99 | dm_block_t root; | ||
100 | dm_block_t hint_root; | ||
101 | dm_block_t discard_root; | ||
102 | |||
103 | sector_t discard_block_size; | ||
104 | dm_dblock_t discard_nr_blocks; | ||
105 | |||
106 | sector_t data_block_size; | ||
107 | dm_cblock_t cache_blocks; | ||
108 | bool changed:1; | ||
109 | bool clean_when_opened:1; | ||
110 | |||
111 | char policy_name[CACHE_POLICY_NAME_SIZE]; | ||
112 | size_t policy_hint_size; | ||
113 | struct dm_cache_statistics stats; | ||
114 | }; | ||
115 | |||
116 | /*------------------------------------------------------------------- | ||
117 | * superblock validator | ||
118 | *-----------------------------------------------------------------*/ | ||
119 | |||
120 | #define SUPERBLOCK_CSUM_XOR 9031977 | ||
121 | |||
122 | static void sb_prepare_for_write(struct dm_block_validator *v, | ||
123 | struct dm_block *b, | ||
124 | size_t sb_block_size) | ||
125 | { | ||
126 | struct cache_disk_superblock *disk_super = dm_block_data(b); | ||
127 | |||
128 | disk_super->blocknr = cpu_to_le64(dm_block_location(b)); | ||
129 | disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags, | ||
130 | sb_block_size - sizeof(__le32), | ||
131 | SUPERBLOCK_CSUM_XOR)); | ||
132 | } | ||
133 | |||
134 | static int sb_check(struct dm_block_validator *v, | ||
135 | struct dm_block *b, | ||
136 | size_t sb_block_size) | ||
137 | { | ||
138 | struct cache_disk_superblock *disk_super = dm_block_data(b); | ||
139 | __le32 csum_le; | ||
140 | |||
141 | if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) { | ||
142 | DMERR("sb_check failed: blocknr %llu: wanted %llu", | ||
143 | le64_to_cpu(disk_super->blocknr), | ||
144 | (unsigned long long)dm_block_location(b)); | ||
145 | return -ENOTBLK; | ||
146 | } | ||
147 | |||
148 | if (le64_to_cpu(disk_super->magic) != CACHE_SUPERBLOCK_MAGIC) { | ||
149 | DMERR("sb_check failed: magic %llu: wanted %llu", | ||
150 | le64_to_cpu(disk_super->magic), | ||
151 | (unsigned long long)CACHE_SUPERBLOCK_MAGIC); | ||
152 | return -EILSEQ; | ||
153 | } | ||
154 | |||
155 | csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags, | ||
156 | sb_block_size - sizeof(__le32), | ||
157 | SUPERBLOCK_CSUM_XOR)); | ||
158 | if (csum_le != disk_super->csum) { | ||
159 | DMERR("sb_check failed: csum %u: wanted %u", | ||
160 | le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum)); | ||
161 | return -EILSEQ; | ||
162 | } | ||
163 | |||
164 | return 0; | ||
165 | } | ||
166 | |||
167 | static struct dm_block_validator sb_validator = { | ||
168 | .name = "superblock", | ||
169 | .prepare_for_write = sb_prepare_for_write, | ||
170 | .check = sb_check | ||
171 | }; | ||
172 | |||
173 | /*----------------------------------------------------------------*/ | ||
174 | |||
175 | static int superblock_read_lock(struct dm_cache_metadata *cmd, | ||
176 | struct dm_block **sblock) | ||
177 | { | ||
178 | return dm_bm_read_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION, | ||
179 | &sb_validator, sblock); | ||
180 | } | ||
181 | |||
182 | static int superblock_lock_zero(struct dm_cache_metadata *cmd, | ||
183 | struct dm_block **sblock) | ||
184 | { | ||
185 | return dm_bm_write_lock_zero(cmd->bm, CACHE_SUPERBLOCK_LOCATION, | ||
186 | &sb_validator, sblock); | ||
187 | } | ||
188 | |||
189 | static int superblock_lock(struct dm_cache_metadata *cmd, | ||
190 | struct dm_block **sblock) | ||
191 | { | ||
192 | return dm_bm_write_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION, | ||
193 | &sb_validator, sblock); | ||
194 | } | ||
195 | |||
196 | /*----------------------------------------------------------------*/ | ||
197 | |||
198 | static int __superblock_all_zeroes(struct dm_block_manager *bm, int *result) | ||
199 | { | ||
200 | int r; | ||
201 | unsigned i; | ||
202 | struct dm_block *b; | ||
203 | __le64 *data_le, zero = cpu_to_le64(0); | ||
204 | unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64); | ||
205 | |||
206 | /* | ||
207 | * We can't use a validator here - it may be all zeroes. | ||
208 | */ | ||
209 | r = dm_bm_read_lock(bm, CACHE_SUPERBLOCK_LOCATION, NULL, &b); | ||
210 | if (r) | ||
211 | return r; | ||
212 | |||
213 | data_le = dm_block_data(b); | ||
214 | *result = 1; | ||
215 | for (i = 0; i < sb_block_size; i++) { | ||
216 | if (data_le[i] != zero) { | ||
217 | *result = 0; | ||
218 | break; | ||
219 | } | ||
220 | } | ||
221 | |||
222 | return dm_bm_unlock(b); | ||
223 | } | ||
224 | |||
225 | static void __setup_mapping_info(struct dm_cache_metadata *cmd) | ||
226 | { | ||
227 | struct dm_btree_value_type vt; | ||
228 | |||
229 | vt.context = NULL; | ||
230 | vt.size = sizeof(__le64); | ||
231 | vt.inc = NULL; | ||
232 | vt.dec = NULL; | ||
233 | vt.equal = NULL; | ||
234 | dm_array_info_init(&cmd->info, cmd->tm, &vt); | ||
235 | |||
236 | if (cmd->policy_hint_size) { | ||
237 | vt.size = sizeof(__le32); | ||
238 | dm_array_info_init(&cmd->hint_info, cmd->tm, &vt); | ||
239 | } | ||
240 | } | ||
241 | |||
242 | static int __write_initial_superblock(struct dm_cache_metadata *cmd) | ||
243 | { | ||
244 | int r; | ||
245 | struct dm_block *sblock; | ||
246 | size_t metadata_len; | ||
247 | struct cache_disk_superblock *disk_super; | ||
248 | sector_t bdev_size = i_size_read(cmd->bdev->bd_inode) >> SECTOR_SHIFT; | ||
249 | |||
250 | /* FIXME: see if we can lose the max sectors limit */ | ||
251 | if (bdev_size > DM_CACHE_METADATA_MAX_SECTORS) | ||
252 | bdev_size = DM_CACHE_METADATA_MAX_SECTORS; | ||
253 | |||
254 | r = dm_sm_root_size(cmd->metadata_sm, &metadata_len); | ||
255 | if (r < 0) | ||
256 | return r; | ||
257 | |||
258 | r = dm_tm_pre_commit(cmd->tm); | ||
259 | if (r < 0) | ||
260 | return r; | ||
261 | |||
262 | r = superblock_lock_zero(cmd, &sblock); | ||
263 | if (r) | ||
264 | return r; | ||
265 | |||
266 | disk_super = dm_block_data(sblock); | ||
267 | disk_super->flags = 0; | ||
268 | memset(disk_super->uuid, 0, sizeof(disk_super->uuid)); | ||
269 | disk_super->magic = cpu_to_le64(CACHE_SUPERBLOCK_MAGIC); | ||
270 | disk_super->version = cpu_to_le32(CACHE_VERSION); | ||
271 | memset(disk_super->policy_name, 0, CACHE_POLICY_NAME_SIZE); | ||
272 | disk_super->policy_hint_size = 0; | ||
273 | |||
274 | r = dm_sm_copy_root(cmd->metadata_sm, &disk_super->metadata_space_map_root, | ||
275 | metadata_len); | ||
276 | if (r < 0) | ||
277 | goto bad_locked; | ||
278 | |||
279 | disk_super->mapping_root = cpu_to_le64(cmd->root); | ||
280 | disk_super->hint_root = cpu_to_le64(cmd->hint_root); | ||
281 | disk_super->discard_root = cpu_to_le64(cmd->discard_root); | ||
282 | disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size); | ||
283 | disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks)); | ||
284 | disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE >> SECTOR_SHIFT); | ||
285 | disk_super->data_block_size = cpu_to_le32(cmd->data_block_size); | ||
286 | disk_super->cache_blocks = cpu_to_le32(0); | ||
287 | memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name)); | ||
288 | |||
289 | disk_super->read_hits = cpu_to_le32(0); | ||
290 | disk_super->read_misses = cpu_to_le32(0); | ||
291 | disk_super->write_hits = cpu_to_le32(0); | ||
292 | disk_super->write_misses = cpu_to_le32(0); | ||
293 | |||
294 | return dm_tm_commit(cmd->tm, sblock); | ||
295 | |||
296 | bad_locked: | ||
297 | dm_bm_unlock(sblock); | ||
298 | return r; | ||
299 | } | ||
300 | |||
301 | static int __format_metadata(struct dm_cache_metadata *cmd) | ||
302 | { | ||
303 | int r; | ||
304 | |||
305 | r = dm_tm_create_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION, | ||
306 | &cmd->tm, &cmd->metadata_sm); | ||
307 | if (r < 0) { | ||
308 | DMERR("tm_create_with_sm failed"); | ||
309 | return r; | ||
310 | } | ||
311 | |||
312 | __setup_mapping_info(cmd); | ||
313 | |||
314 | r = dm_array_empty(&cmd->info, &cmd->root); | ||
315 | if (r < 0) | ||
316 | goto bad; | ||
317 | |||
318 | dm_disk_bitset_init(cmd->tm, &cmd->discard_info); | ||
319 | |||
320 | r = dm_bitset_empty(&cmd->discard_info, &cmd->discard_root); | ||
321 | if (r < 0) | ||
322 | goto bad; | ||
323 | |||
324 | cmd->discard_block_size = 0; | ||
325 | cmd->discard_nr_blocks = 0; | ||
326 | |||
327 | r = __write_initial_superblock(cmd); | ||
328 | if (r) | ||
329 | goto bad; | ||
330 | |||
331 | cmd->clean_when_opened = true; | ||
332 | return 0; | ||
333 | |||
334 | bad: | ||
335 | dm_tm_destroy(cmd->tm); | ||
336 | dm_sm_destroy(cmd->metadata_sm); | ||
337 | |||
338 | return r; | ||
339 | } | ||
340 | |||
341 | static int __check_incompat_features(struct cache_disk_superblock *disk_super, | ||
342 | struct dm_cache_metadata *cmd) | ||
343 | { | ||
344 | uint32_t features; | ||
345 | |||
346 | features = le32_to_cpu(disk_super->incompat_flags) & ~DM_CACHE_FEATURE_INCOMPAT_SUPP; | ||
347 | if (features) { | ||
348 | DMERR("could not access metadata due to unsupported optional features (%lx).", | ||
349 | (unsigned long)features); | ||
350 | return -EINVAL; | ||
351 | } | ||
352 | |||
353 | /* | ||
354 | * Check for read-only metadata to skip the following RDWR checks. | ||
355 | */ | ||
356 | if (get_disk_ro(cmd->bdev->bd_disk)) | ||
357 | return 0; | ||
358 | |||
359 | features = le32_to_cpu(disk_super->compat_ro_flags) & ~DM_CACHE_FEATURE_COMPAT_RO_SUPP; | ||
360 | if (features) { | ||
361 | DMERR("could not access metadata RDWR due to unsupported optional features (%lx).", | ||
362 | (unsigned long)features); | ||
363 | return -EINVAL; | ||
364 | } | ||
365 | |||
366 | return 0; | ||
367 | } | ||
368 | |||
369 | static int __open_metadata(struct dm_cache_metadata *cmd) | ||
370 | { | ||
371 | int r; | ||
372 | struct dm_block *sblock; | ||
373 | struct cache_disk_superblock *disk_super; | ||
374 | unsigned long sb_flags; | ||
375 | |||
376 | r = superblock_read_lock(cmd, &sblock); | ||
377 | if (r < 0) { | ||
378 | DMERR("couldn't read lock superblock"); | ||
379 | return r; | ||
380 | } | ||
381 | |||
382 | disk_super = dm_block_data(sblock); | ||
383 | |||
384 | r = __check_incompat_features(disk_super, cmd); | ||
385 | if (r < 0) | ||
386 | goto bad; | ||
387 | |||
388 | r = dm_tm_open_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION, | ||
389 | disk_super->metadata_space_map_root, | ||
390 | sizeof(disk_super->metadata_space_map_root), | ||
391 | &cmd->tm, &cmd->metadata_sm); | ||
392 | if (r < 0) { | ||
393 | DMERR("tm_open_with_sm failed"); | ||
394 | goto bad; | ||
395 | } | ||
396 | |||
397 | __setup_mapping_info(cmd); | ||
398 | dm_disk_bitset_init(cmd->tm, &cmd->discard_info); | ||
399 | sb_flags = le32_to_cpu(disk_super->flags); | ||
400 | cmd->clean_when_opened = test_bit(CLEAN_SHUTDOWN, &sb_flags); | ||
401 | return dm_bm_unlock(sblock); | ||
402 | |||
403 | bad: | ||
404 | dm_bm_unlock(sblock); | ||
405 | return r; | ||
406 | } | ||
407 | |||
408 | static int __open_or_format_metadata(struct dm_cache_metadata *cmd, | ||
409 | bool format_device) | ||
410 | { | ||
411 | int r, unformatted; | ||
412 | |||
413 | r = __superblock_all_zeroes(cmd->bm, &unformatted); | ||
414 | if (r) | ||
415 | return r; | ||
416 | |||
417 | if (unformatted) | ||
418 | return format_device ? __format_metadata(cmd) : -EPERM; | ||
419 | |||
420 | return __open_metadata(cmd); | ||
421 | } | ||
422 | |||
423 | static int __create_persistent_data_objects(struct dm_cache_metadata *cmd, | ||
424 | bool may_format_device) | ||
425 | { | ||
426 | int r; | ||
427 | cmd->bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE, | ||
428 | CACHE_METADATA_CACHE_SIZE, | ||
429 | CACHE_MAX_CONCURRENT_LOCKS); | ||
430 | if (IS_ERR(cmd->bm)) { | ||
431 | DMERR("could not create block manager"); | ||
432 | return PTR_ERR(cmd->bm); | ||
433 | } | ||
434 | |||
435 | r = __open_or_format_metadata(cmd, may_format_device); | ||
436 | if (r) | ||
437 | dm_block_manager_destroy(cmd->bm); | ||
438 | |||
439 | return r; | ||
440 | } | ||
441 | |||
442 | static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd) | ||
443 | { | ||
444 | dm_sm_destroy(cmd->metadata_sm); | ||
445 | dm_tm_destroy(cmd->tm); | ||
446 | dm_block_manager_destroy(cmd->bm); | ||
447 | } | ||
448 | |||
449 | typedef unsigned long (*flags_mutator)(unsigned long); | ||
450 | |||
451 | static void update_flags(struct cache_disk_superblock *disk_super, | ||
452 | flags_mutator mutator) | ||
453 | { | ||
454 | uint32_t sb_flags = mutator(le32_to_cpu(disk_super->flags)); | ||
455 | disk_super->flags = cpu_to_le32(sb_flags); | ||
456 | } | ||
457 | |||
458 | static unsigned long set_clean_shutdown(unsigned long flags) | ||
459 | { | ||
460 | set_bit(CLEAN_SHUTDOWN, &flags); | ||
461 | return flags; | ||
462 | } | ||
463 | |||
464 | static unsigned long clear_clean_shutdown(unsigned long flags) | ||
465 | { | ||
466 | clear_bit(CLEAN_SHUTDOWN, &flags); | ||
467 | return flags; | ||
468 | } | ||
469 | |||
470 | static void read_superblock_fields(struct dm_cache_metadata *cmd, | ||
471 | struct cache_disk_superblock *disk_super) | ||
472 | { | ||
473 | cmd->root = le64_to_cpu(disk_super->mapping_root); | ||
474 | cmd->hint_root = le64_to_cpu(disk_super->hint_root); | ||
475 | cmd->discard_root = le64_to_cpu(disk_super->discard_root); | ||
476 | cmd->discard_block_size = le64_to_cpu(disk_super->discard_block_size); | ||
477 | cmd->discard_nr_blocks = to_dblock(le64_to_cpu(disk_super->discard_nr_blocks)); | ||
478 | cmd->data_block_size = le32_to_cpu(disk_super->data_block_size); | ||
479 | cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks)); | ||
480 | strncpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name)); | ||
481 | cmd->policy_hint_size = le32_to_cpu(disk_super->policy_hint_size); | ||
482 | |||
483 | cmd->stats.read_hits = le32_to_cpu(disk_super->read_hits); | ||
484 | cmd->stats.read_misses = le32_to_cpu(disk_super->read_misses); | ||
485 | cmd->stats.write_hits = le32_to_cpu(disk_super->write_hits); | ||
486 | cmd->stats.write_misses = le32_to_cpu(disk_super->write_misses); | ||
487 | |||
488 | cmd->changed = false; | ||
489 | } | ||
490 | |||
491 | /* | ||
492 | * The mutator updates the superblock flags. | ||
493 | */ | ||
494 | static int __begin_transaction_flags(struct dm_cache_metadata *cmd, | ||
495 | flags_mutator mutator) | ||
496 | { | ||
497 | int r; | ||
498 | struct cache_disk_superblock *disk_super; | ||
499 | struct dm_block *sblock; | ||
500 | |||
501 | r = superblock_lock(cmd, &sblock); | ||
502 | if (r) | ||
503 | return r; | ||
504 | |||
505 | disk_super = dm_block_data(sblock); | ||
506 | update_flags(disk_super, mutator); | ||
507 | read_superblock_fields(cmd, disk_super); | ||
508 | |||
509 | return dm_bm_flush_and_unlock(cmd->bm, sblock); | ||
510 | } | ||
511 | |||
512 | static int __begin_transaction(struct dm_cache_metadata *cmd) | ||
513 | { | ||
514 | int r; | ||
515 | struct cache_disk_superblock *disk_super; | ||
516 | struct dm_block *sblock; | ||
517 | |||
518 | /* | ||
519 | * We re-read the superblock every time. Shouldn't need to do this | ||
520 | * really. | ||
521 | */ | ||
522 | r = superblock_read_lock(cmd, &sblock); | ||
523 | if (r) | ||
524 | return r; | ||
525 | |||
526 | disk_super = dm_block_data(sblock); | ||
527 | read_superblock_fields(cmd, disk_super); | ||
528 | dm_bm_unlock(sblock); | ||
529 | |||
530 | return 0; | ||
531 | } | ||
532 | |||
533 | static int __commit_transaction(struct dm_cache_metadata *cmd, | ||
534 | flags_mutator mutator) | ||
535 | { | ||
536 | int r; | ||
537 | size_t metadata_len; | ||
538 | struct cache_disk_superblock *disk_super; | ||
539 | struct dm_block *sblock; | ||
540 | |||
541 | /* | ||
542 | * We need to know if the cache_disk_superblock exceeds a 512-byte sector. | ||
543 | */ | ||
544 | BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512); | ||
545 | |||
546 | r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root, | ||
547 | &cmd->discard_root); | ||
548 | if (r) | ||
549 | return r; | ||
550 | |||
551 | r = dm_tm_pre_commit(cmd->tm); | ||
552 | if (r < 0) | ||
553 | return r; | ||
554 | |||
555 | r = dm_sm_root_size(cmd->metadata_sm, &metadata_len); | ||
556 | if (r < 0) | ||
557 | return r; | ||
558 | |||
559 | r = superblock_lock(cmd, &sblock); | ||
560 | if (r) | ||
561 | return r; | ||
562 | |||
563 | disk_super = dm_block_data(sblock); | ||
564 | |||
565 | if (mutator) | ||
566 | update_flags(disk_super, mutator); | ||
567 | |||
568 | disk_super->mapping_root = cpu_to_le64(cmd->root); | ||
569 | disk_super->hint_root = cpu_to_le64(cmd->hint_root); | ||
570 | disk_super->discard_root = cpu_to_le64(cmd->discard_root); | ||
571 | disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size); | ||
572 | disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks)); | ||
573 | disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks)); | ||
574 | strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name)); | ||
575 | |||
576 | disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits); | ||
577 | disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses); | ||
578 | disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits); | ||
579 | disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses); | ||
580 | |||
581 | r = dm_sm_copy_root(cmd->metadata_sm, &disk_super->metadata_space_map_root, | ||
582 | metadata_len); | ||
583 | if (r < 0) { | ||
584 | dm_bm_unlock(sblock); | ||
585 | return r; | ||
586 | } | ||
587 | |||
588 | return dm_tm_commit(cmd->tm, sblock); | ||
589 | } | ||
590 | |||
591 | /*----------------------------------------------------------------*/ | ||
592 | |||
593 | /* | ||
594 | * The mappings are held in a dm-array that has 64-bit values stored in | ||
595 | * little-endian format. The index is the cblock, the high 48bits of the | ||
596 | * value are the oblock and the low 16 bit the flags. | ||
597 | */ | ||
598 | #define FLAGS_MASK ((1 << 16) - 1) | ||
599 | |||
600 | static __le64 pack_value(dm_oblock_t block, unsigned flags) | ||
601 | { | ||
602 | uint64_t value = from_oblock(block); | ||
603 | value <<= 16; | ||
604 | value = value | (flags & FLAGS_MASK); | ||
605 | return cpu_to_le64(value); | ||
606 | } | ||
607 | |||
608 | static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags) | ||
609 | { | ||
610 | uint64_t value = le64_to_cpu(value_le); | ||
611 | uint64_t b = value >> 16; | ||
612 | *block = to_oblock(b); | ||
613 | *flags = value & FLAGS_MASK; | ||
614 | } | ||
615 | |||
616 | /*----------------------------------------------------------------*/ | ||
617 | |||
618 | struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev, | ||
619 | sector_t data_block_size, | ||
620 | bool may_format_device, | ||
621 | size_t policy_hint_size) | ||
622 | { | ||
623 | int r; | ||
624 | struct dm_cache_metadata *cmd; | ||
625 | |||
626 | cmd = kzalloc(sizeof(*cmd), GFP_KERNEL); | ||
627 | if (!cmd) { | ||
628 | DMERR("could not allocate metadata struct"); | ||
629 | return NULL; | ||
630 | } | ||
631 | |||
632 | init_rwsem(&cmd->root_lock); | ||
633 | cmd->bdev = bdev; | ||
634 | cmd->data_block_size = data_block_size; | ||
635 | cmd->cache_blocks = 0; | ||
636 | cmd->policy_hint_size = policy_hint_size; | ||
637 | cmd->changed = true; | ||
638 | |||
639 | r = __create_persistent_data_objects(cmd, may_format_device); | ||
640 | if (r) { | ||
641 | kfree(cmd); | ||
642 | return ERR_PTR(r); | ||
643 | } | ||
644 | |||
645 | r = __begin_transaction_flags(cmd, clear_clean_shutdown); | ||
646 | if (r < 0) { | ||
647 | dm_cache_metadata_close(cmd); | ||
648 | return ERR_PTR(r); | ||
649 | } | ||
650 | |||
651 | return cmd; | ||
652 | } | ||
653 | |||
654 | void dm_cache_metadata_close(struct dm_cache_metadata *cmd) | ||
655 | { | ||
656 | __destroy_persistent_data_objects(cmd); | ||
657 | kfree(cmd); | ||
658 | } | ||
659 | |||
660 | int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size) | ||
661 | { | ||
662 | int r; | ||
663 | __le64 null_mapping = pack_value(0, 0); | ||
664 | |||
665 | down_write(&cmd->root_lock); | ||
666 | __dm_bless_for_disk(&null_mapping); | ||
667 | r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks), | ||
668 | from_cblock(new_cache_size), | ||
669 | &null_mapping, &cmd->root); | ||
670 | if (!r) | ||
671 | cmd->cache_blocks = new_cache_size; | ||
672 | cmd->changed = true; | ||
673 | up_write(&cmd->root_lock); | ||
674 | |||
675 | return r; | ||
676 | } | ||
677 | |||
678 | int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd, | ||
679 | sector_t discard_block_size, | ||
680 | dm_dblock_t new_nr_entries) | ||
681 | { | ||
682 | int r; | ||
683 | |||
684 | down_write(&cmd->root_lock); | ||
685 | r = dm_bitset_resize(&cmd->discard_info, | ||
686 | cmd->discard_root, | ||
687 | from_dblock(cmd->discard_nr_blocks), | ||
688 | from_dblock(new_nr_entries), | ||
689 | false, &cmd->discard_root); | ||
690 | if (!r) { | ||
691 | cmd->discard_block_size = discard_block_size; | ||
692 | cmd->discard_nr_blocks = new_nr_entries; | ||
693 | } | ||
694 | |||
695 | cmd->changed = true; | ||
696 | up_write(&cmd->root_lock); | ||
697 | |||
698 | return r; | ||
699 | } | ||
700 | |||
701 | static int __set_discard(struct dm_cache_metadata *cmd, dm_dblock_t b) | ||
702 | { | ||
703 | return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root, | ||
704 | from_dblock(b), &cmd->discard_root); | ||
705 | } | ||
706 | |||
707 | static int __clear_discard(struct dm_cache_metadata *cmd, dm_dblock_t b) | ||
708 | { | ||
709 | return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root, | ||
710 | from_dblock(b), &cmd->discard_root); | ||
711 | } | ||
712 | |||
713 | static int __is_discarded(struct dm_cache_metadata *cmd, dm_dblock_t b, | ||
714 | bool *is_discarded) | ||
715 | { | ||
716 | return dm_bitset_test_bit(&cmd->discard_info, cmd->discard_root, | ||
717 | from_dblock(b), &cmd->discard_root, | ||
718 | is_discarded); | ||
719 | } | ||
720 | |||
721 | static int __discard(struct dm_cache_metadata *cmd, | ||
722 | dm_dblock_t dblock, bool discard) | ||
723 | { | ||
724 | int r; | ||
725 | |||
726 | r = (discard ? __set_discard : __clear_discard)(cmd, dblock); | ||
727 | if (r) | ||
728 | return r; | ||
729 | |||
730 | cmd->changed = true; | ||
731 | return 0; | ||
732 | } | ||
733 | |||
734 | int dm_cache_set_discard(struct dm_cache_metadata *cmd, | ||
735 | dm_dblock_t dblock, bool discard) | ||
736 | { | ||
737 | int r; | ||
738 | |||
739 | down_write(&cmd->root_lock); | ||
740 | r = __discard(cmd, dblock, discard); | ||
741 | up_write(&cmd->root_lock); | ||
742 | |||
743 | return r; | ||
744 | } | ||
745 | |||
746 | static int __load_discards(struct dm_cache_metadata *cmd, | ||
747 | load_discard_fn fn, void *context) | ||
748 | { | ||
749 | int r = 0; | ||
750 | dm_block_t b; | ||
751 | bool discard; | ||
752 | |||
753 | for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) { | ||
754 | dm_dblock_t dblock = to_dblock(b); | ||
755 | |||
756 | if (cmd->clean_when_opened) { | ||
757 | r = __is_discarded(cmd, dblock, &discard); | ||
758 | if (r) | ||
759 | return r; | ||
760 | } else | ||
761 | discard = false; | ||
762 | |||
763 | r = fn(context, cmd->discard_block_size, dblock, discard); | ||
764 | if (r) | ||
765 | break; | ||
766 | } | ||
767 | |||
768 | return r; | ||
769 | } | ||
770 | |||
771 | int dm_cache_load_discards(struct dm_cache_metadata *cmd, | ||
772 | load_discard_fn fn, void *context) | ||
773 | { | ||
774 | int r; | ||
775 | |||
776 | down_read(&cmd->root_lock); | ||
777 | r = __load_discards(cmd, fn, context); | ||
778 | up_read(&cmd->root_lock); | ||
779 | |||
780 | return r; | ||
781 | } | ||
782 | |||
783 | dm_cblock_t dm_cache_size(struct dm_cache_metadata *cmd) | ||
784 | { | ||
785 | dm_cblock_t r; | ||
786 | |||
787 | down_read(&cmd->root_lock); | ||
788 | r = cmd->cache_blocks; | ||
789 | up_read(&cmd->root_lock); | ||
790 | |||
791 | return r; | ||
792 | } | ||
793 | |||
794 | static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock) | ||
795 | { | ||
796 | int r; | ||
797 | __le64 value = pack_value(0, 0); | ||
798 | |||
799 | __dm_bless_for_disk(&value); | ||
800 | r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), | ||
801 | &value, &cmd->root); | ||
802 | if (r) | ||
803 | return r; | ||
804 | |||
805 | cmd->changed = true; | ||
806 | return 0; | ||
807 | } | ||
808 | |||
809 | int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock) | ||
810 | { | ||
811 | int r; | ||
812 | |||
813 | down_write(&cmd->root_lock); | ||
814 | r = __remove(cmd, cblock); | ||
815 | up_write(&cmd->root_lock); | ||
816 | |||
817 | return r; | ||
818 | } | ||
819 | |||
820 | static int __insert(struct dm_cache_metadata *cmd, | ||
821 | dm_cblock_t cblock, dm_oblock_t oblock) | ||
822 | { | ||
823 | int r; | ||
824 | __le64 value = pack_value(oblock, M_VALID); | ||
825 | __dm_bless_for_disk(&value); | ||
826 | |||
827 | r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), | ||
828 | &value, &cmd->root); | ||
829 | if (r) | ||
830 | return r; | ||
831 | |||
832 | cmd->changed = true; | ||
833 | return 0; | ||
834 | } | ||
835 | |||
836 | int dm_cache_insert_mapping(struct dm_cache_metadata *cmd, | ||
837 | dm_cblock_t cblock, dm_oblock_t oblock) | ||
838 | { | ||
839 | int r; | ||
840 | |||
841 | down_write(&cmd->root_lock); | ||
842 | r = __insert(cmd, cblock, oblock); | ||
843 | up_write(&cmd->root_lock); | ||
844 | |||
845 | return r; | ||
846 | } | ||
847 | |||
848 | struct thunk { | ||
849 | load_mapping_fn fn; | ||
850 | void *context; | ||
851 | |||
852 | struct dm_cache_metadata *cmd; | ||
853 | bool respect_dirty_flags; | ||
854 | bool hints_valid; | ||
855 | }; | ||
856 | |||
857 | static bool hints_array_initialized(struct dm_cache_metadata *cmd) | ||
858 | { | ||
859 | return cmd->hint_root && cmd->policy_hint_size; | ||
860 | } | ||
861 | |||
862 | static bool hints_array_available(struct dm_cache_metadata *cmd, | ||
863 | const char *policy_name) | ||
864 | { | ||
865 | bool policy_names_match = !strncmp(cmd->policy_name, policy_name, | ||
866 | sizeof(cmd->policy_name)); | ||
867 | |||
868 | return cmd->clean_when_opened && policy_names_match && | ||
869 | hints_array_initialized(cmd); | ||
870 | } | ||
871 | |||
872 | static int __load_mapping(void *context, uint64_t cblock, void *leaf) | ||
873 | { | ||
874 | int r = 0; | ||
875 | bool dirty; | ||
876 | __le64 value; | ||
877 | __le32 hint_value = 0; | ||
878 | dm_oblock_t oblock; | ||
879 | unsigned flags; | ||
880 | struct thunk *thunk = context; | ||
881 | struct dm_cache_metadata *cmd = thunk->cmd; | ||
882 | |||
883 | memcpy(&value, leaf, sizeof(value)); | ||
884 | unpack_value(value, &oblock, &flags); | ||
885 | |||
886 | if (flags & M_VALID) { | ||
887 | if (thunk->hints_valid) { | ||
888 | r = dm_array_get_value(&cmd->hint_info, cmd->hint_root, | ||
889 | cblock, &hint_value); | ||
890 | if (r && r != -ENODATA) | ||
891 | return r; | ||
892 | } | ||
893 | |||
894 | dirty = thunk->respect_dirty_flags ? (flags & M_DIRTY) : true; | ||
895 | r = thunk->fn(thunk->context, oblock, to_cblock(cblock), | ||
896 | dirty, le32_to_cpu(hint_value), thunk->hints_valid); | ||
897 | } | ||
898 | |||
899 | return r; | ||
900 | } | ||
901 | |||
902 | static int __load_mappings(struct dm_cache_metadata *cmd, const char *policy_name, | ||
903 | load_mapping_fn fn, void *context) | ||
904 | { | ||
905 | struct thunk thunk; | ||
906 | |||
907 | thunk.fn = fn; | ||
908 | thunk.context = context; | ||
909 | |||
910 | thunk.cmd = cmd; | ||
911 | thunk.respect_dirty_flags = cmd->clean_when_opened; | ||
912 | thunk.hints_valid = hints_array_available(cmd, policy_name); | ||
913 | |||
914 | return dm_array_walk(&cmd->info, cmd->root, __load_mapping, &thunk); | ||
915 | } | ||
916 | |||
917 | int dm_cache_load_mappings(struct dm_cache_metadata *cmd, const char *policy_name, | ||
918 | load_mapping_fn fn, void *context) | ||
919 | { | ||
920 | int r; | ||
921 | |||
922 | down_read(&cmd->root_lock); | ||
923 | r = __load_mappings(cmd, policy_name, fn, context); | ||
924 | up_read(&cmd->root_lock); | ||
925 | |||
926 | return r; | ||
927 | } | ||
928 | |||
929 | static int __dump_mapping(void *context, uint64_t cblock, void *leaf) | ||
930 | { | ||
931 | int r = 0; | ||
932 | __le64 value; | ||
933 | dm_oblock_t oblock; | ||
934 | unsigned flags; | ||
935 | |||
936 | memcpy(&value, leaf, sizeof(value)); | ||
937 | unpack_value(value, &oblock, &flags); | ||
938 | |||
939 | return r; | ||
940 | } | ||
941 | |||
942 | static int __dump_mappings(struct dm_cache_metadata *cmd) | ||
943 | { | ||
944 | return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL); | ||
945 | } | ||
946 | |||
947 | void dm_cache_dump(struct dm_cache_metadata *cmd) | ||
948 | { | ||
949 | down_read(&cmd->root_lock); | ||
950 | __dump_mappings(cmd); | ||
951 | up_read(&cmd->root_lock); | ||
952 | } | ||
953 | |||
954 | int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd) | ||
955 | { | ||
956 | int r; | ||
957 | |||
958 | down_read(&cmd->root_lock); | ||
959 | r = cmd->changed; | ||
960 | up_read(&cmd->root_lock); | ||
961 | |||
962 | return r; | ||
963 | } | ||
964 | |||
965 | static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty) | ||
966 | { | ||
967 | int r; | ||
968 | unsigned flags; | ||
969 | dm_oblock_t oblock; | ||
970 | __le64 value; | ||
971 | |||
972 | r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value); | ||
973 | if (r) | ||
974 | return r; | ||
975 | |||
976 | unpack_value(value, &oblock, &flags); | ||
977 | |||
978 | if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty)) | ||
979 | /* nothing to be done */ | ||
980 | return 0; | ||
981 | |||
982 | value = pack_value(oblock, flags | (dirty ? M_DIRTY : 0)); | ||
983 | __dm_bless_for_disk(&value); | ||
984 | |||
985 | r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), | ||
986 | &value, &cmd->root); | ||
987 | if (r) | ||
988 | return r; | ||
989 | |||
990 | cmd->changed = true; | ||
991 | return 0; | ||
992 | |||
993 | } | ||
994 | |||
995 | int dm_cache_set_dirty(struct dm_cache_metadata *cmd, | ||
996 | dm_cblock_t cblock, bool dirty) | ||
997 | { | ||
998 | int r; | ||
999 | |||
1000 | down_write(&cmd->root_lock); | ||
1001 | r = __dirty(cmd, cblock, dirty); | ||
1002 | up_write(&cmd->root_lock); | ||
1003 | |||
1004 | return r; | ||
1005 | } | ||
1006 | |||
1007 | void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd, | ||
1008 | struct dm_cache_statistics *stats) | ||
1009 | { | ||
1010 | down_read(&cmd->root_lock); | ||
1011 | memcpy(stats, &cmd->stats, sizeof(*stats)); | ||
1012 | up_read(&cmd->root_lock); | ||
1013 | } | ||
1014 | |||
1015 | void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd, | ||
1016 | struct dm_cache_statistics *stats) | ||
1017 | { | ||
1018 | down_write(&cmd->root_lock); | ||
1019 | memcpy(&cmd->stats, stats, sizeof(*stats)); | ||
1020 | up_write(&cmd->root_lock); | ||
1021 | } | ||
1022 | |||
1023 | int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown) | ||
1024 | { | ||
1025 | int r; | ||
1026 | flags_mutator mutator = (clean_shutdown ? set_clean_shutdown : | ||
1027 | clear_clean_shutdown); | ||
1028 | |||
1029 | down_write(&cmd->root_lock); | ||
1030 | r = __commit_transaction(cmd, mutator); | ||
1031 | if (r) | ||
1032 | goto out; | ||
1033 | |||
1034 | r = __begin_transaction(cmd); | ||
1035 | |||
1036 | out: | ||
1037 | up_write(&cmd->root_lock); | ||
1038 | return r; | ||
1039 | } | ||
1040 | |||
1041 | int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd, | ||
1042 | dm_block_t *result) | ||
1043 | { | ||
1044 | int r = -EINVAL; | ||
1045 | |||
1046 | down_read(&cmd->root_lock); | ||
1047 | r = dm_sm_get_nr_free(cmd->metadata_sm, result); | ||
1048 | up_read(&cmd->root_lock); | ||
1049 | |||
1050 | return r; | ||
1051 | } | ||
1052 | |||
1053 | int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd, | ||
1054 | dm_block_t *result) | ||
1055 | { | ||
1056 | int r = -EINVAL; | ||
1057 | |||
1058 | down_read(&cmd->root_lock); | ||
1059 | r = dm_sm_get_nr_blocks(cmd->metadata_sm, result); | ||
1060 | up_read(&cmd->root_lock); | ||
1061 | |||
1062 | return r; | ||
1063 | } | ||
1064 | |||
1065 | /*----------------------------------------------------------------*/ | ||
1066 | |||
1067 | static int begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy) | ||
1068 | { | ||
1069 | int r; | ||
1070 | __le32 value; | ||
1071 | size_t hint_size; | ||
1072 | const char *policy_name = dm_cache_policy_get_name(policy); | ||
1073 | |||
1074 | if (!policy_name[0] || | ||
1075 | (strlen(policy_name) > sizeof(cmd->policy_name) - 1)) | ||
1076 | return -EINVAL; | ||
1077 | |||
1078 | if (strcmp(cmd->policy_name, policy_name)) { | ||
1079 | strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name)); | ||
1080 | |||
1081 | hint_size = dm_cache_policy_get_hint_size(policy); | ||
1082 | if (!hint_size) | ||
1083 | return 0; /* short-circuit hints initialization */ | ||
1084 | cmd->policy_hint_size = hint_size; | ||
1085 | |||
1086 | if (cmd->hint_root) { | ||
1087 | r = dm_array_del(&cmd->hint_info, cmd->hint_root); | ||
1088 | if (r) | ||
1089 | return r; | ||
1090 | } | ||
1091 | |||
1092 | r = dm_array_empty(&cmd->hint_info, &cmd->hint_root); | ||
1093 | if (r) | ||
1094 | return r; | ||
1095 | |||
1096 | value = cpu_to_le32(0); | ||
1097 | __dm_bless_for_disk(&value); | ||
1098 | r = dm_array_resize(&cmd->hint_info, cmd->hint_root, 0, | ||
1099 | from_cblock(cmd->cache_blocks), | ||
1100 | &value, &cmd->hint_root); | ||
1101 | if (r) | ||
1102 | return r; | ||
1103 | } | ||
1104 | |||
1105 | return 0; | ||
1106 | } | ||
1107 | |||
1108 | int dm_cache_begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy) | ||
1109 | { | ||
1110 | int r; | ||
1111 | |||
1112 | down_write(&cmd->root_lock); | ||
1113 | r = begin_hints(cmd, policy); | ||
1114 | up_write(&cmd->root_lock); | ||
1115 | |||
1116 | return r; | ||
1117 | } | ||
1118 | |||
1119 | static int save_hint(struct dm_cache_metadata *cmd, dm_cblock_t cblock, | ||
1120 | uint32_t hint) | ||
1121 | { | ||
1122 | int r; | ||
1123 | __le32 value = cpu_to_le32(hint); | ||
1124 | __dm_bless_for_disk(&value); | ||
1125 | |||
1126 | r = dm_array_set_value(&cmd->hint_info, cmd->hint_root, | ||
1127 | from_cblock(cblock), &value, &cmd->hint_root); | ||
1128 | cmd->changed = true; | ||
1129 | |||
1130 | return r; | ||
1131 | } | ||
1132 | |||
1133 | int dm_cache_save_hint(struct dm_cache_metadata *cmd, dm_cblock_t cblock, | ||
1134 | uint32_t hint) | ||
1135 | { | ||
1136 | int r; | ||
1137 | |||
1138 | if (!hints_array_initialized(cmd)) | ||
1139 | return 0; | ||
1140 | |||
1141 | down_write(&cmd->root_lock); | ||
1142 | r = save_hint(cmd, cblock, hint); | ||
1143 | up_write(&cmd->root_lock); | ||
1144 | |||
1145 | return r; | ||
1146 | } | ||
diff --git a/drivers/md/dm-cache-metadata.h b/drivers/md/dm-cache-metadata.h new file mode 100644 index 000000000000..135864ea0eee --- /dev/null +++ b/drivers/md/dm-cache-metadata.h | |||
@@ -0,0 +1,142 @@ | |||
1 | /* | ||
2 | * Copyright (C) 2012 Red Hat, Inc. | ||
3 | * | ||
4 | * This file is released under the GPL. | ||
5 | */ | ||
6 | |||
7 | #ifndef DM_CACHE_METADATA_H | ||
8 | #define DM_CACHE_METADATA_H | ||
9 | |||
10 | #include "dm-cache-block-types.h" | ||
11 | #include "dm-cache-policy-internal.h" | ||
12 | |||
13 | /*----------------------------------------------------------------*/ | ||
14 | |||
15 | #define DM_CACHE_METADATA_BLOCK_SIZE 4096 | ||
16 | |||
17 | /* FIXME: remove this restriction */ | ||
18 | /* | ||
19 | * The metadata device is currently limited in size. | ||
20 | * | ||
21 | * We have one block of index, which can hold 255 index entries. Each | ||
22 | * index entry contains allocation info about 16k metadata blocks. | ||
23 | */ | ||
24 | #define DM_CACHE_METADATA_MAX_SECTORS (255 * (1 << 14) * (DM_CACHE_METADATA_BLOCK_SIZE / (1 << SECTOR_SHIFT))) | ||
25 | |||
26 | /* | ||
27 | * A metadata device larger than 16GB triggers a warning. | ||
28 | */ | ||
29 | #define DM_CACHE_METADATA_MAX_SECTORS_WARNING (16 * (1024 * 1024 * 1024 >> SECTOR_SHIFT)) | ||
30 | |||
31 | /*----------------------------------------------------------------*/ | ||
32 | |||
33 | /* | ||
34 | * Ext[234]-style compat feature flags. | ||
35 | * | ||
36 | * A new feature which old metadata will still be compatible with should | ||
37 | * define a DM_CACHE_FEATURE_COMPAT_* flag (rarely useful). | ||
38 | * | ||
39 | * A new feature that is not compatible with old code should define a | ||
40 | * DM_CACHE_FEATURE_INCOMPAT_* flag and guard the relevant code with | ||
41 | * that flag. | ||
42 | * | ||
43 | * A new feature that is not compatible with old code accessing the | ||
44 | * metadata RDWR should define a DM_CACHE_FEATURE_RO_COMPAT_* flag and | ||
45 | * guard the relevant code with that flag. | ||
46 | * | ||
47 | * As these various flags are defined they should be added to the | ||
48 | * following masks. | ||
49 | */ | ||
50 | #define DM_CACHE_FEATURE_COMPAT_SUPP 0UL | ||
51 | #define DM_CACHE_FEATURE_COMPAT_RO_SUPP 0UL | ||
52 | #define DM_CACHE_FEATURE_INCOMPAT_SUPP 0UL | ||
53 | |||
54 | /* | ||
55 | * Reopens or creates a new, empty metadata volume. | ||
56 | * Returns an ERR_PTR on failure. | ||
57 | */ | ||
58 | struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev, | ||
59 | sector_t data_block_size, | ||
60 | bool may_format_device, | ||
61 | size_t policy_hint_size); | ||
62 | |||
63 | void dm_cache_metadata_close(struct dm_cache_metadata *cmd); | ||
64 | |||
65 | /* | ||
66 | * The metadata needs to know how many cache blocks there are. We don't | ||
67 | * care about the origin, assuming the core target is giving us valid | ||
68 | * origin blocks to map to. | ||
69 | */ | ||
70 | int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size); | ||
71 | dm_cblock_t dm_cache_size(struct dm_cache_metadata *cmd); | ||
72 | |||
73 | int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd, | ||
74 | sector_t discard_block_size, | ||
75 | dm_dblock_t new_nr_entries); | ||
76 | |||
77 | typedef int (*load_discard_fn)(void *context, sector_t discard_block_size, | ||
78 | dm_dblock_t dblock, bool discarded); | ||
79 | int dm_cache_load_discards(struct dm_cache_metadata *cmd, | ||
80 | load_discard_fn fn, void *context); | ||
81 | |||
82 | int dm_cache_set_discard(struct dm_cache_metadata *cmd, dm_dblock_t dblock, bool discard); | ||
83 | |||
84 | int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock); | ||
85 | int dm_cache_insert_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock, dm_oblock_t oblock); | ||
86 | int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd); | ||
87 | |||
88 | typedef int (*load_mapping_fn)(void *context, dm_oblock_t oblock, | ||
89 | dm_cblock_t cblock, bool dirty, | ||
90 | uint32_t hint, bool hint_valid); | ||
91 | int dm_cache_load_mappings(struct dm_cache_metadata *cmd, | ||
92 | const char *policy_name, | ||
93 | load_mapping_fn fn, | ||
94 | void *context); | ||
95 | |||
96 | int dm_cache_set_dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty); | ||
97 | |||
98 | struct dm_cache_statistics { | ||
99 | uint32_t read_hits; | ||
100 | uint32_t read_misses; | ||
101 | uint32_t write_hits; | ||
102 | uint32_t write_misses; | ||
103 | }; | ||
104 | |||
105 | void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd, | ||
106 | struct dm_cache_statistics *stats); | ||
107 | void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd, | ||
108 | struct dm_cache_statistics *stats); | ||
109 | |||
110 | int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown); | ||
111 | |||
112 | int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd, | ||
113 | dm_block_t *result); | ||
114 | |||
115 | int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd, | ||
116 | dm_block_t *result); | ||
117 | |||
118 | void dm_cache_dump(struct dm_cache_metadata *cmd); | ||
119 | |||
120 | /* | ||
121 | * The policy is invited to save a 32bit hint value for every cblock (eg, | ||
122 | * for a hit count). These are stored against the policy name. If | ||
123 | * policies are changed, then hints will be lost. If the machine crashes, | ||
124 | * hints will be lost. | ||
125 | * | ||
126 | * The hints are indexed by the cblock, but many policies will not | ||
127 | * neccessarily have a fast way of accessing efficiently via cblock. So | ||
128 | * rather than querying the policy for each cblock, we let it walk its data | ||
129 | * structures and fill in the hints in whatever order it wishes. | ||
130 | */ | ||
131 | |||
132 | int dm_cache_begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *p); | ||
133 | |||
134 | /* | ||
135 | * requests hints for every cblock and stores in the metadata device. | ||
136 | */ | ||
137 | int dm_cache_save_hint(struct dm_cache_metadata *cmd, | ||
138 | dm_cblock_t cblock, uint32_t hint); | ||
139 | |||
140 | /*----------------------------------------------------------------*/ | ||
141 | |||
142 | #endif /* DM_CACHE_METADATA_H */ | ||
diff --git a/drivers/md/dm-cache-policy-internal.h b/drivers/md/dm-cache-policy-internal.h new file mode 100644 index 000000000000..52a75beeced5 --- /dev/null +++ b/drivers/md/dm-cache-policy-internal.h | |||
@@ -0,0 +1,124 @@ | |||
1 | /* | ||
2 | * Copyright (C) 2012 Red Hat. All rights reserved. | ||
3 | * | ||
4 | * This file is released under the GPL. | ||
5 | */ | ||
6 | |||
7 | #ifndef DM_CACHE_POLICY_INTERNAL_H | ||
8 | #define DM_CACHE_POLICY_INTERNAL_H | ||
9 | |||
10 | #include "dm-cache-policy.h" | ||
11 | |||
12 | /*----------------------------------------------------------------*/ | ||
13 | |||
14 | /* | ||
15 | * Little inline functions that simplify calling the policy methods. | ||
16 | */ | ||
17 | static inline int policy_map(struct dm_cache_policy *p, dm_oblock_t oblock, | ||
18 | bool can_block, bool can_migrate, bool discarded_oblock, | ||
19 | struct bio *bio, struct policy_result *result) | ||
20 | { | ||
21 | return p->map(p, oblock, can_block, can_migrate, discarded_oblock, bio, result); | ||
22 | } | ||
23 | |||
24 | static inline int policy_lookup(struct dm_cache_policy *p, dm_oblock_t oblock, dm_cblock_t *cblock) | ||
25 | { | ||
26 | BUG_ON(!p->lookup); | ||
27 | return p->lookup(p, oblock, cblock); | ||
28 | } | ||
29 | |||
30 | static inline void policy_set_dirty(struct dm_cache_policy *p, dm_oblock_t oblock) | ||
31 | { | ||
32 | if (p->set_dirty) | ||
33 | p->set_dirty(p, oblock); | ||
34 | } | ||
35 | |||
36 | static inline void policy_clear_dirty(struct dm_cache_policy *p, dm_oblock_t oblock) | ||
37 | { | ||
38 | if (p->clear_dirty) | ||
39 | p->clear_dirty(p, oblock); | ||
40 | } | ||
41 | |||
42 | static inline int policy_load_mapping(struct dm_cache_policy *p, | ||
43 | dm_oblock_t oblock, dm_cblock_t cblock, | ||
44 | uint32_t hint, bool hint_valid) | ||
45 | { | ||
46 | return p->load_mapping(p, oblock, cblock, hint, hint_valid); | ||
47 | } | ||
48 | |||
49 | static inline int policy_walk_mappings(struct dm_cache_policy *p, | ||
50 | policy_walk_fn fn, void *context) | ||
51 | { | ||
52 | return p->walk_mappings ? p->walk_mappings(p, fn, context) : 0; | ||
53 | } | ||
54 | |||
55 | static inline int policy_writeback_work(struct dm_cache_policy *p, | ||
56 | dm_oblock_t *oblock, | ||
57 | dm_cblock_t *cblock) | ||
58 | { | ||
59 | return p->writeback_work ? p->writeback_work(p, oblock, cblock) : -ENOENT; | ||
60 | } | ||
61 | |||
62 | static inline void policy_remove_mapping(struct dm_cache_policy *p, dm_oblock_t oblock) | ||
63 | { | ||
64 | return p->remove_mapping(p, oblock); | ||
65 | } | ||
66 | |||
67 | static inline void policy_force_mapping(struct dm_cache_policy *p, | ||
68 | dm_oblock_t current_oblock, dm_oblock_t new_oblock) | ||
69 | { | ||
70 | return p->force_mapping(p, current_oblock, new_oblock); | ||
71 | } | ||
72 | |||
73 | static inline dm_cblock_t policy_residency(struct dm_cache_policy *p) | ||
74 | { | ||
75 | return p->residency(p); | ||
76 | } | ||
77 | |||
78 | static inline void policy_tick(struct dm_cache_policy *p) | ||
79 | { | ||
80 | if (p->tick) | ||
81 | return p->tick(p); | ||
82 | } | ||
83 | |||
84 | static inline int policy_emit_config_values(struct dm_cache_policy *p, char *result, unsigned maxlen) | ||
85 | { | ||
86 | ssize_t sz = 0; | ||
87 | if (p->emit_config_values) | ||
88 | return p->emit_config_values(p, result, maxlen); | ||
89 | |||
90 | DMEMIT("0"); | ||
91 | return 0; | ||
92 | } | ||
93 | |||
94 | static inline int policy_set_config_value(struct dm_cache_policy *p, | ||
95 | const char *key, const char *value) | ||
96 | { | ||
97 | return p->set_config_value ? p->set_config_value(p, key, value) : -EINVAL; | ||
98 | } | ||
99 | |||
100 | /*----------------------------------------------------------------*/ | ||
101 | |||
102 | /* | ||
103 | * Creates a new cache policy given a policy name, a cache size, an origin size and the block size. | ||
104 | */ | ||
105 | struct dm_cache_policy *dm_cache_policy_create(const char *name, dm_cblock_t cache_size, | ||
106 | sector_t origin_size, sector_t block_size); | ||
107 | |||
108 | /* | ||
109 | * Destroys the policy. This drops references to the policy module as well | ||
110 | * as calling it's destroy method. So always use this rather than calling | ||
111 | * the policy->destroy method directly. | ||
112 | */ | ||
113 | void dm_cache_policy_destroy(struct dm_cache_policy *p); | ||
114 | |||
115 | /* | ||
116 | * In case we've forgotten. | ||
117 | */ | ||
118 | const char *dm_cache_policy_get_name(struct dm_cache_policy *p); | ||
119 | |||
120 | size_t dm_cache_policy_get_hint_size(struct dm_cache_policy *p); | ||
121 | |||
122 | /*----------------------------------------------------------------*/ | ||
123 | |||
124 | #endif /* DM_CACHE_POLICY_INTERNAL_H */ | ||
diff --git a/drivers/md/dm-cache-policy.c b/drivers/md/dm-cache-policy.c new file mode 100644 index 000000000000..2cbf5fdaac52 --- /dev/null +++ b/drivers/md/dm-cache-policy.c | |||
@@ -0,0 +1,161 @@ | |||
1 | /* | ||
2 | * Copyright (C) 2012 Red Hat. All rights reserved. | ||
3 | * | ||
4 | * This file is released under the GPL. | ||
5 | */ | ||
6 | |||
7 | #include "dm-cache-policy-internal.h" | ||
8 | #include "dm.h" | ||
9 | |||
10 | #include <linux/module.h> | ||
11 | #include <linux/slab.h> | ||
12 | |||
13 | /*----------------------------------------------------------------*/ | ||
14 | |||
15 | #define DM_MSG_PREFIX "cache-policy" | ||
16 | |||
17 | static DEFINE_SPINLOCK(register_lock); | ||
18 | static LIST_HEAD(register_list); | ||
19 | |||
20 | static struct dm_cache_policy_type *__find_policy(const char *name) | ||
21 | { | ||
22 | struct dm_cache_policy_type *t; | ||
23 | |||
24 | list_for_each_entry(t, ®ister_list, list) | ||
25 | if (!strcmp(t->name, name)) | ||
26 | return t; | ||
27 | |||
28 | return NULL; | ||
29 | } | ||
30 | |||
31 | static struct dm_cache_policy_type *__get_policy_once(const char *name) | ||
32 | { | ||
33 | struct dm_cache_policy_type *t = __find_policy(name); | ||
34 | |||
35 | if (t && !try_module_get(t->owner)) { | ||
36 | DMWARN("couldn't get module %s", name); | ||
37 | t = ERR_PTR(-EINVAL); | ||
38 | } | ||
39 | |||
40 | return t; | ||
41 | } | ||
42 | |||
43 | static struct dm_cache_policy_type *get_policy_once(const char *name) | ||
44 | { | ||
45 | struct dm_cache_policy_type *t; | ||
46 | |||
47 | spin_lock(®ister_lock); | ||
48 | t = __get_policy_once(name); | ||
49 | spin_unlock(®ister_lock); | ||
50 | |||
51 | return t; | ||
52 | } | ||
53 | |||
54 | static struct dm_cache_policy_type *get_policy(const char *name) | ||
55 | { | ||
56 | struct dm_cache_policy_type *t; | ||
57 | |||
58 | t = get_policy_once(name); | ||
59 | if (IS_ERR(t)) | ||
60 | return NULL; | ||
61 | |||
62 | if (t) | ||
63 | return t; | ||
64 | |||
65 | request_module("dm-cache-%s", name); | ||
66 | |||
67 | t = get_policy_once(name); | ||
68 | if (IS_ERR(t)) | ||
69 | return NULL; | ||
70 | |||
71 | return t; | ||
72 | } | ||
73 | |||
74 | static void put_policy(struct dm_cache_policy_type *t) | ||
75 | { | ||
76 | module_put(t->owner); | ||
77 | } | ||
78 | |||
79 | int dm_cache_policy_register(struct dm_cache_policy_type *type) | ||
80 | { | ||
81 | int r; | ||
82 | |||
83 | /* One size fits all for now */ | ||
84 | if (type->hint_size != 0 && type->hint_size != 4) { | ||
85 | DMWARN("hint size must be 0 or 4 but %llu supplied.", (unsigned long long) type->hint_size); | ||
86 | return -EINVAL; | ||
87 | } | ||
88 | |||
89 | spin_lock(®ister_lock); | ||
90 | if (__find_policy(type->name)) { | ||
91 | DMWARN("attempt to register policy under duplicate name %s", type->name); | ||
92 | r = -EINVAL; | ||
93 | } else { | ||
94 | list_add(&type->list, ®ister_list); | ||
95 | r = 0; | ||
96 | } | ||
97 | spin_unlock(®ister_lock); | ||
98 | |||
99 | return r; | ||
100 | } | ||
101 | EXPORT_SYMBOL_GPL(dm_cache_policy_register); | ||
102 | |||
103 | void dm_cache_policy_unregister(struct dm_cache_policy_type *type) | ||
104 | { | ||
105 | spin_lock(®ister_lock); | ||
106 | list_del_init(&type->list); | ||
107 | spin_unlock(®ister_lock); | ||
108 | } | ||
109 | EXPORT_SYMBOL_GPL(dm_cache_policy_unregister); | ||
110 | |||
111 | struct dm_cache_policy *dm_cache_policy_create(const char *name, | ||
112 | dm_cblock_t cache_size, | ||
113 | sector_t origin_size, | ||
114 | sector_t cache_block_size) | ||
115 | { | ||
116 | struct dm_cache_policy *p = NULL; | ||
117 | struct dm_cache_policy_type *type; | ||
118 | |||
119 | type = get_policy(name); | ||
120 | if (!type) { | ||
121 | DMWARN("unknown policy type"); | ||
122 | return NULL; | ||
123 | } | ||
124 | |||
125 | p = type->create(cache_size, origin_size, cache_block_size); | ||
126 | if (!p) { | ||
127 | put_policy(type); | ||
128 | return NULL; | ||
129 | } | ||
130 | p->private = type; | ||
131 | |||
132 | return p; | ||
133 | } | ||
134 | EXPORT_SYMBOL_GPL(dm_cache_policy_create); | ||
135 | |||
136 | void dm_cache_policy_destroy(struct dm_cache_policy *p) | ||
137 | { | ||
138 | struct dm_cache_policy_type *t = p->private; | ||
139 | |||
140 | p->destroy(p); | ||
141 | put_policy(t); | ||
142 | } | ||
143 | EXPORT_SYMBOL_GPL(dm_cache_policy_destroy); | ||
144 | |||
145 | const char *dm_cache_policy_get_name(struct dm_cache_policy *p) | ||
146 | { | ||
147 | struct dm_cache_policy_type *t = p->private; | ||
148 | |||
149 | return t->name; | ||
150 | } | ||
151 | EXPORT_SYMBOL_GPL(dm_cache_policy_get_name); | ||
152 | |||
153 | size_t dm_cache_policy_get_hint_size(struct dm_cache_policy *p) | ||
154 | { | ||
155 | struct dm_cache_policy_type *t = p->private; | ||
156 | |||
157 | return t->hint_size; | ||
158 | } | ||
159 | EXPORT_SYMBOL_GPL(dm_cache_policy_get_hint_size); | ||
160 | |||
161 | /*----------------------------------------------------------------*/ | ||
diff --git a/drivers/md/dm-cache-policy.h b/drivers/md/dm-cache-policy.h new file mode 100644 index 000000000000..f0f51b260544 --- /dev/null +++ b/drivers/md/dm-cache-policy.h | |||
@@ -0,0 +1,228 @@ | |||
1 | /* | ||
2 | * Copyright (C) 2012 Red Hat. All rights reserved. | ||
3 | * | ||
4 | * This file is released under the GPL. | ||
5 | */ | ||
6 | |||
7 | #ifndef DM_CACHE_POLICY_H | ||
8 | #define DM_CACHE_POLICY_H | ||
9 | |||
10 | #include "dm-cache-block-types.h" | ||
11 | |||
12 | #include <linux/device-mapper.h> | ||
13 | |||
14 | /*----------------------------------------------------------------*/ | ||
15 | |||
16 | /* FIXME: make it clear which methods are optional. Get debug policy to | ||
17 | * double check this at start. | ||
18 | */ | ||
19 | |||
20 | /* | ||
21 | * The cache policy makes the important decisions about which blocks get to | ||
22 | * live on the faster cache device. | ||
23 | * | ||
24 | * When the core target has to remap a bio it calls the 'map' method of the | ||
25 | * policy. This returns an instruction telling the core target what to do. | ||
26 | * | ||
27 | * POLICY_HIT: | ||
28 | * That block is in the cache. Remap to the cache and carry on. | ||
29 | * | ||
30 | * POLICY_MISS: | ||
31 | * This block is on the origin device. Remap and carry on. | ||
32 | * | ||
33 | * POLICY_NEW: | ||
34 | * This block is currently on the origin device, but the policy wants to | ||
35 | * move it. The core should: | ||
36 | * | ||
37 | * - hold any further io to this origin block | ||
38 | * - copy the origin to the given cache block | ||
39 | * - release all the held blocks | ||
40 | * - remap the original block to the cache | ||
41 | * | ||
42 | * POLICY_REPLACE: | ||
43 | * This block is currently on the origin device. The policy wants to | ||
44 | * move it to the cache, with the added complication that the destination | ||
45 | * cache block needs a writeback first. The core should: | ||
46 | * | ||
47 | * - hold any further io to this origin block | ||
48 | * - hold any further io to the origin block that's being written back | ||
49 | * - writeback | ||
50 | * - copy new block to cache | ||
51 | * - release held blocks | ||
52 | * - remap bio to cache and reissue. | ||
53 | * | ||
54 | * Should the core run into trouble while processing a POLICY_NEW or | ||
55 | * POLICY_REPLACE instruction it will roll back the policies mapping using | ||
56 | * remove_mapping() or force_mapping(). These methods must not fail. This | ||
57 | * approach avoids having transactional semantics in the policy (ie, the | ||
58 | * core informing the policy when a migration is complete), and hence makes | ||
59 | * it easier to write new policies. | ||
60 | * | ||
61 | * In general policy methods should never block, except in the case of the | ||
62 | * map function when can_migrate is set. So be careful to implement using | ||
63 | * bounded, preallocated memory. | ||
64 | */ | ||
65 | enum policy_operation { | ||
66 | POLICY_HIT, | ||
67 | POLICY_MISS, | ||
68 | POLICY_NEW, | ||
69 | POLICY_REPLACE | ||
70 | }; | ||
71 | |||
72 | /* | ||
73 | * This is the instruction passed back to the core target. | ||
74 | */ | ||
75 | struct policy_result { | ||
76 | enum policy_operation op; | ||
77 | dm_oblock_t old_oblock; /* POLICY_REPLACE */ | ||
78 | dm_cblock_t cblock; /* POLICY_HIT, POLICY_NEW, POLICY_REPLACE */ | ||
79 | }; | ||
80 | |||
81 | typedef int (*policy_walk_fn)(void *context, dm_cblock_t cblock, | ||
82 | dm_oblock_t oblock, uint32_t hint); | ||
83 | |||
84 | /* | ||
85 | * The cache policy object. Just a bunch of methods. It is envisaged that | ||
86 | * this structure will be embedded in a bigger, policy specific structure | ||
87 | * (ie. use container_of()). | ||
88 | */ | ||
89 | struct dm_cache_policy { | ||
90 | |||
91 | /* | ||
92 | * FIXME: make it clear which methods are optional, and which may | ||
93 | * block. | ||
94 | */ | ||
95 | |||
96 | /* | ||
97 | * Destroys this object. | ||
98 | */ | ||
99 | void (*destroy)(struct dm_cache_policy *p); | ||
100 | |||
101 | /* | ||
102 | * See large comment above. | ||
103 | * | ||
104 | * oblock - the origin block we're interested in. | ||
105 | * | ||
106 | * can_block - indicates whether the current thread is allowed to | ||
107 | * block. -EWOULDBLOCK returned if it can't and would. | ||
108 | * | ||
109 | * can_migrate - gives permission for POLICY_NEW or POLICY_REPLACE | ||
110 | * instructions. If denied and the policy would have | ||
111 | * returned one of these instructions it should | ||
112 | * return -EWOULDBLOCK. | ||
113 | * | ||
114 | * discarded_oblock - indicates whether the whole origin block is | ||
115 | * in a discarded state (FIXME: better to tell the | ||
116 | * policy about this sooner, so it can recycle that | ||
117 | * cache block if it wants.) | ||
118 | * bio - the bio that triggered this call. | ||
119 | * result - gets filled in with the instruction. | ||
120 | * | ||
121 | * May only return 0, or -EWOULDBLOCK (if !can_migrate) | ||
122 | */ | ||
123 | int (*map)(struct dm_cache_policy *p, dm_oblock_t oblock, | ||
124 | bool can_block, bool can_migrate, bool discarded_oblock, | ||
125 | struct bio *bio, struct policy_result *result); | ||
126 | |||
127 | /* | ||
128 | * Sometimes we want to see if a block is in the cache, without | ||
129 | * triggering any update of stats. (ie. it's not a real hit). | ||
130 | * | ||
131 | * Must not block. | ||
132 | * | ||
133 | * Returns 1 iff in cache, 0 iff not, < 0 on error (-EWOULDBLOCK | ||
134 | * would be typical). | ||
135 | */ | ||
136 | int (*lookup)(struct dm_cache_policy *p, dm_oblock_t oblock, dm_cblock_t *cblock); | ||
137 | |||
138 | /* | ||
139 | * oblock must be a mapped block. Must not block. | ||
140 | */ | ||
141 | void (*set_dirty)(struct dm_cache_policy *p, dm_oblock_t oblock); | ||
142 | void (*clear_dirty)(struct dm_cache_policy *p, dm_oblock_t oblock); | ||
143 | |||
144 | /* | ||
145 | * Called when a cache target is first created. Used to load a | ||
146 | * mapping from the metadata device into the policy. | ||
147 | */ | ||
148 | int (*load_mapping)(struct dm_cache_policy *p, dm_oblock_t oblock, | ||
149 | dm_cblock_t cblock, uint32_t hint, bool hint_valid); | ||
150 | |||
151 | int (*walk_mappings)(struct dm_cache_policy *p, policy_walk_fn fn, | ||
152 | void *context); | ||
153 | |||
154 | /* | ||
155 | * Override functions used on the error paths of the core target. | ||
156 | * They must succeed. | ||
157 | */ | ||
158 | void (*remove_mapping)(struct dm_cache_policy *p, dm_oblock_t oblock); | ||
159 | void (*force_mapping)(struct dm_cache_policy *p, dm_oblock_t current_oblock, | ||
160 | dm_oblock_t new_oblock); | ||
161 | |||
162 | int (*writeback_work)(struct dm_cache_policy *p, dm_oblock_t *oblock, dm_cblock_t *cblock); | ||
163 | |||
164 | |||
165 | /* | ||
166 | * How full is the cache? | ||
167 | */ | ||
168 | dm_cblock_t (*residency)(struct dm_cache_policy *p); | ||
169 | |||
170 | /* | ||
171 | * Because of where we sit in the block layer, we can be asked to | ||
172 | * map a lot of little bios that are all in the same block (no | ||
173 | * queue merging has occurred). To stop the policy being fooled by | ||
174 | * these the core target sends regular tick() calls to the policy. | ||
175 | * The policy should only count an entry as hit once per tick. | ||
176 | */ | ||
177 | void (*tick)(struct dm_cache_policy *p); | ||
178 | |||
179 | /* | ||
180 | * Configuration. | ||
181 | */ | ||
182 | int (*emit_config_values)(struct dm_cache_policy *p, | ||
183 | char *result, unsigned maxlen); | ||
184 | int (*set_config_value)(struct dm_cache_policy *p, | ||
185 | const char *key, const char *value); | ||
186 | |||
187 | /* | ||
188 | * Book keeping ptr for the policy register, not for general use. | ||
189 | */ | ||
190 | void *private; | ||
191 | }; | ||
192 | |||
193 | /*----------------------------------------------------------------*/ | ||
194 | |||
195 | /* | ||
196 | * We maintain a little register of the different policy types. | ||
197 | */ | ||
198 | #define CACHE_POLICY_NAME_SIZE 16 | ||
199 | |||
200 | struct dm_cache_policy_type { | ||
201 | /* For use by the register code only. */ | ||
202 | struct list_head list; | ||
203 | |||
204 | /* | ||
205 | * Policy writers should fill in these fields. The name field is | ||
206 | * what gets passed on the target line to select your policy. | ||
207 | */ | ||
208 | char name[CACHE_POLICY_NAME_SIZE]; | ||
209 | |||
210 | /* | ||
211 | * Policies may store a hint for each each cache block. | ||
212 | * Currently the size of this hint must be 0 or 4 bytes but we | ||
213 | * expect to relax this in future. | ||
214 | */ | ||
215 | size_t hint_size; | ||
216 | |||
217 | struct module *owner; | ||
218 | struct dm_cache_policy *(*create)(dm_cblock_t cache_size, | ||
219 | sector_t origin_size, | ||
220 | sector_t block_size); | ||
221 | }; | ||
222 | |||
223 | int dm_cache_policy_register(struct dm_cache_policy_type *type); | ||
224 | void dm_cache_policy_unregister(struct dm_cache_policy_type *type); | ||
225 | |||
226 | /*----------------------------------------------------------------*/ | ||
227 | |||
228 | #endif /* DM_CACHE_POLICY_H */ | ||
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c new file mode 100644 index 000000000000..0f4e84b15c30 --- /dev/null +++ b/drivers/md/dm-cache-target.c | |||
@@ -0,0 +1,2584 @@ | |||
1 | /* | ||
2 | * Copyright (C) 2012 Red Hat. All rights reserved. | ||
3 | * | ||
4 | * This file is released under the GPL. | ||
5 | */ | ||
6 | |||
7 | #include "dm.h" | ||
8 | #include "dm-bio-prison.h" | ||
9 | #include "dm-cache-metadata.h" | ||
10 | |||
11 | #include <linux/dm-io.h> | ||
12 | #include <linux/dm-kcopyd.h> | ||
13 | #include <linux/init.h> | ||
14 | #include <linux/mempool.h> | ||
15 | #include <linux/module.h> | ||
16 | #include <linux/slab.h> | ||
17 | #include <linux/vmalloc.h> | ||
18 | |||
19 | #define DM_MSG_PREFIX "cache" | ||
20 | |||
21 | DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(cache_copy_throttle, | ||
22 | "A percentage of time allocated for copying to and/or from cache"); | ||
23 | |||
24 | /*----------------------------------------------------------------*/ | ||
25 | |||
26 | /* | ||
27 | * Glossary: | ||
28 | * | ||
29 | * oblock: index of an origin block | ||
30 | * cblock: index of a cache block | ||
31 | * promotion: movement of a block from origin to cache | ||
32 | * demotion: movement of a block from cache to origin | ||
33 | * migration: movement of a block between the origin and cache device, | ||
34 | * either direction | ||
35 | */ | ||
36 | |||
37 | /*----------------------------------------------------------------*/ | ||
38 | |||
39 | static size_t bitset_size_in_bytes(unsigned nr_entries) | ||
40 | { | ||
41 | return sizeof(unsigned long) * dm_div_up(nr_entries, BITS_PER_LONG); | ||
42 | } | ||
43 | |||
44 | static unsigned long *alloc_bitset(unsigned nr_entries) | ||
45 | { | ||
46 | size_t s = bitset_size_in_bytes(nr_entries); | ||
47 | return vzalloc(s); | ||
48 | } | ||
49 | |||
50 | static void clear_bitset(void *bitset, unsigned nr_entries) | ||
51 | { | ||
52 | size_t s = bitset_size_in_bytes(nr_entries); | ||
53 | memset(bitset, 0, s); | ||
54 | } | ||
55 | |||
56 | static void free_bitset(unsigned long *bits) | ||
57 | { | ||
58 | vfree(bits); | ||
59 | } | ||
60 | |||
61 | /*----------------------------------------------------------------*/ | ||
62 | |||
63 | #define PRISON_CELLS 1024 | ||
64 | #define MIGRATION_POOL_SIZE 128 | ||
65 | #define COMMIT_PERIOD HZ | ||
66 | #define MIGRATION_COUNT_WINDOW 10 | ||
67 | |||
68 | /* | ||
69 | * The block size of the device holding cache data must be >= 32KB | ||
70 | */ | ||
71 | #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (32 * 1024 >> SECTOR_SHIFT) | ||
72 | |||
73 | /* | ||
74 | * FIXME: the cache is read/write for the time being. | ||
75 | */ | ||
76 | enum cache_mode { | ||
77 | CM_WRITE, /* metadata may be changed */ | ||
78 | CM_READ_ONLY, /* metadata may not be changed */ | ||
79 | }; | ||
80 | |||
81 | struct cache_features { | ||
82 | enum cache_mode mode; | ||
83 | bool write_through:1; | ||
84 | }; | ||
85 | |||
86 | struct cache_stats { | ||
87 | atomic_t read_hit; | ||
88 | atomic_t read_miss; | ||
89 | atomic_t write_hit; | ||
90 | atomic_t write_miss; | ||
91 | atomic_t demotion; | ||
92 | atomic_t promotion; | ||
93 | atomic_t copies_avoided; | ||
94 | atomic_t cache_cell_clash; | ||
95 | atomic_t commit_count; | ||
96 | atomic_t discard_count; | ||
97 | }; | ||
98 | |||
99 | struct cache { | ||
100 | struct dm_target *ti; | ||
101 | struct dm_target_callbacks callbacks; | ||
102 | |||
103 | /* | ||
104 | * Metadata is written to this device. | ||
105 | */ | ||
106 | struct dm_dev *metadata_dev; | ||
107 | |||
108 | /* | ||
109 | * The slower of the two data devices. Typically a spindle. | ||
110 | */ | ||
111 | struct dm_dev *origin_dev; | ||
112 | |||
113 | /* | ||
114 | * The faster of the two data devices. Typically an SSD. | ||
115 | */ | ||
116 | struct dm_dev *cache_dev; | ||
117 | |||
118 | /* | ||
119 | * Cache features such as write-through. | ||
120 | */ | ||
121 | struct cache_features features; | ||
122 | |||
123 | /* | ||
124 | * Size of the origin device in _complete_ blocks and native sectors. | ||
125 | */ | ||
126 | dm_oblock_t origin_blocks; | ||
127 | sector_t origin_sectors; | ||
128 | |||
129 | /* | ||
130 | * Size of the cache device in blocks. | ||
131 | */ | ||
132 | dm_cblock_t cache_size; | ||
133 | |||
134 | /* | ||
135 | * Fields for converting from sectors to blocks. | ||
136 | */ | ||
137 | uint32_t sectors_per_block; | ||
138 | int sectors_per_block_shift; | ||
139 | |||
140 | struct dm_cache_metadata *cmd; | ||
141 | |||
142 | spinlock_t lock; | ||
143 | struct bio_list deferred_bios; | ||
144 | struct bio_list deferred_flush_bios; | ||
145 | struct list_head quiesced_migrations; | ||
146 | struct list_head completed_migrations; | ||
147 | struct list_head need_commit_migrations; | ||
148 | sector_t migration_threshold; | ||
149 | atomic_t nr_migrations; | ||
150 | wait_queue_head_t migration_wait; | ||
151 | |||
152 | /* | ||
153 | * cache_size entries, dirty if set | ||
154 | */ | ||
155 | dm_cblock_t nr_dirty; | ||
156 | unsigned long *dirty_bitset; | ||
157 | |||
158 | /* | ||
159 | * origin_blocks entries, discarded if set. | ||
160 | */ | ||
161 | sector_t discard_block_size; /* a power of 2 times sectors per block */ | ||
162 | dm_dblock_t discard_nr_blocks; | ||
163 | unsigned long *discard_bitset; | ||
164 | |||
165 | struct dm_kcopyd_client *copier; | ||
166 | struct workqueue_struct *wq; | ||
167 | struct work_struct worker; | ||
168 | |||
169 | struct delayed_work waker; | ||
170 | unsigned long last_commit_jiffies; | ||
171 | |||
172 | struct dm_bio_prison *prison; | ||
173 | struct dm_deferred_set *all_io_ds; | ||
174 | |||
175 | mempool_t *migration_pool; | ||
176 | struct dm_cache_migration *next_migration; | ||
177 | |||
178 | struct dm_cache_policy *policy; | ||
179 | unsigned policy_nr_args; | ||
180 | |||
181 | bool need_tick_bio:1; | ||
182 | bool sized:1; | ||
183 | bool quiescing:1; | ||
184 | bool commit_requested:1; | ||
185 | bool loaded_mappings:1; | ||
186 | bool loaded_discards:1; | ||
187 | |||
188 | struct cache_stats stats; | ||
189 | |||
190 | /* | ||
191 | * Rather than reconstructing the table line for the status we just | ||
192 | * save it and regurgitate. | ||
193 | */ | ||
194 | unsigned nr_ctr_args; | ||
195 | const char **ctr_args; | ||
196 | }; | ||
197 | |||
198 | struct per_bio_data { | ||
199 | bool tick:1; | ||
200 | unsigned req_nr:2; | ||
201 | struct dm_deferred_entry *all_io_entry; | ||
202 | }; | ||
203 | |||
204 | struct dm_cache_migration { | ||
205 | struct list_head list; | ||
206 | struct cache *cache; | ||
207 | |||
208 | unsigned long start_jiffies; | ||
209 | dm_oblock_t old_oblock; | ||
210 | dm_oblock_t new_oblock; | ||
211 | dm_cblock_t cblock; | ||
212 | |||
213 | bool err:1; | ||
214 | bool writeback:1; | ||
215 | bool demote:1; | ||
216 | bool promote:1; | ||
217 | |||
218 | struct dm_bio_prison_cell *old_ocell; | ||
219 | struct dm_bio_prison_cell *new_ocell; | ||
220 | }; | ||
221 | |||
222 | /* | ||
223 | * Processing a bio in the worker thread may require these memory | ||
224 | * allocations. We prealloc to avoid deadlocks (the same worker thread | ||
225 | * frees them back to the mempool). | ||
226 | */ | ||
227 | struct prealloc { | ||
228 | struct dm_cache_migration *mg; | ||
229 | struct dm_bio_prison_cell *cell1; | ||
230 | struct dm_bio_prison_cell *cell2; | ||
231 | }; | ||
232 | |||
233 | static void wake_worker(struct cache *cache) | ||
234 | { | ||
235 | queue_work(cache->wq, &cache->worker); | ||
236 | } | ||
237 | |||
238 | /*----------------------------------------------------------------*/ | ||
239 | |||
240 | static struct dm_bio_prison_cell *alloc_prison_cell(struct cache *cache) | ||
241 | { | ||
242 | /* FIXME: change to use a local slab. */ | ||
243 | return dm_bio_prison_alloc_cell(cache->prison, GFP_NOWAIT); | ||
244 | } | ||
245 | |||
246 | static void free_prison_cell(struct cache *cache, struct dm_bio_prison_cell *cell) | ||
247 | { | ||
248 | dm_bio_prison_free_cell(cache->prison, cell); | ||
249 | } | ||
250 | |||
251 | static int prealloc_data_structs(struct cache *cache, struct prealloc *p) | ||
252 | { | ||
253 | if (!p->mg) { | ||
254 | p->mg = mempool_alloc(cache->migration_pool, GFP_NOWAIT); | ||
255 | if (!p->mg) | ||
256 | return -ENOMEM; | ||
257 | } | ||
258 | |||
259 | if (!p->cell1) { | ||
260 | p->cell1 = alloc_prison_cell(cache); | ||
261 | if (!p->cell1) | ||
262 | return -ENOMEM; | ||
263 | } | ||
264 | |||
265 | if (!p->cell2) { | ||
266 | p->cell2 = alloc_prison_cell(cache); | ||
267 | if (!p->cell2) | ||
268 | return -ENOMEM; | ||
269 | } | ||
270 | |||
271 | return 0; | ||
272 | } | ||
273 | |||
274 | static void prealloc_free_structs(struct cache *cache, struct prealloc *p) | ||
275 | { | ||
276 | if (p->cell2) | ||
277 | free_prison_cell(cache, p->cell2); | ||
278 | |||
279 | if (p->cell1) | ||
280 | free_prison_cell(cache, p->cell1); | ||
281 | |||
282 | if (p->mg) | ||
283 | mempool_free(p->mg, cache->migration_pool); | ||
284 | } | ||
285 | |||
286 | static struct dm_cache_migration *prealloc_get_migration(struct prealloc *p) | ||
287 | { | ||
288 | struct dm_cache_migration *mg = p->mg; | ||
289 | |||
290 | BUG_ON(!mg); | ||
291 | p->mg = NULL; | ||
292 | |||
293 | return mg; | ||
294 | } | ||
295 | |||
296 | /* | ||
297 | * You must have a cell within the prealloc struct to return. If not this | ||
298 | * function will BUG() rather than returning NULL. | ||
299 | */ | ||
300 | static struct dm_bio_prison_cell *prealloc_get_cell(struct prealloc *p) | ||
301 | { | ||
302 | struct dm_bio_prison_cell *r = NULL; | ||
303 | |||
304 | if (p->cell1) { | ||
305 | r = p->cell1; | ||
306 | p->cell1 = NULL; | ||
307 | |||
308 | } else if (p->cell2) { | ||
309 | r = p->cell2; | ||
310 | p->cell2 = NULL; | ||
311 | } else | ||
312 | BUG(); | ||
313 | |||
314 | return r; | ||
315 | } | ||
316 | |||
317 | /* | ||
318 | * You can't have more than two cells in a prealloc struct. BUG() will be | ||
319 | * called if you try and overfill. | ||
320 | */ | ||
321 | static void prealloc_put_cell(struct prealloc *p, struct dm_bio_prison_cell *cell) | ||
322 | { | ||
323 | if (!p->cell2) | ||
324 | p->cell2 = cell; | ||
325 | |||
326 | else if (!p->cell1) | ||
327 | p->cell1 = cell; | ||
328 | |||
329 | else | ||
330 | BUG(); | ||
331 | } | ||
332 | |||
333 | /*----------------------------------------------------------------*/ | ||
334 | |||
335 | static void build_key(dm_oblock_t oblock, struct dm_cell_key *key) | ||
336 | { | ||
337 | key->virtual = 0; | ||
338 | key->dev = 0; | ||
339 | key->block = from_oblock(oblock); | ||
340 | } | ||
341 | |||
342 | /* | ||
343 | * The caller hands in a preallocated cell, and a free function for it. | ||
344 | * The cell will be freed if there's an error, or if it wasn't used because | ||
345 | * a cell with that key already exists. | ||
346 | */ | ||
347 | typedef void (*cell_free_fn)(void *context, struct dm_bio_prison_cell *cell); | ||
348 | |||
349 | static int bio_detain(struct cache *cache, dm_oblock_t oblock, | ||
350 | struct bio *bio, struct dm_bio_prison_cell *cell_prealloc, | ||
351 | cell_free_fn free_fn, void *free_context, | ||
352 | struct dm_bio_prison_cell **cell_result) | ||
353 | { | ||
354 | int r; | ||
355 | struct dm_cell_key key; | ||
356 | |||
357 | build_key(oblock, &key); | ||
358 | r = dm_bio_detain(cache->prison, &key, bio, cell_prealloc, cell_result); | ||
359 | if (r) | ||
360 | free_fn(free_context, cell_prealloc); | ||
361 | |||
362 | return r; | ||
363 | } | ||
364 | |||
365 | static int get_cell(struct cache *cache, | ||
366 | dm_oblock_t oblock, | ||
367 | struct prealloc *structs, | ||
368 | struct dm_bio_prison_cell **cell_result) | ||
369 | { | ||
370 | int r; | ||
371 | struct dm_cell_key key; | ||
372 | struct dm_bio_prison_cell *cell_prealloc; | ||
373 | |||
374 | cell_prealloc = prealloc_get_cell(structs); | ||
375 | |||
376 | build_key(oblock, &key); | ||
377 | r = dm_get_cell(cache->prison, &key, cell_prealloc, cell_result); | ||
378 | if (r) | ||
379 | prealloc_put_cell(structs, cell_prealloc); | ||
380 | |||
381 | return r; | ||
382 | } | ||
383 | |||
384 | /*----------------------------------------------------------------*/ | ||
385 | |||
386 | static bool is_dirty(struct cache *cache, dm_cblock_t b) | ||
387 | { | ||
388 | return test_bit(from_cblock(b), cache->dirty_bitset); | ||
389 | } | ||
390 | |||
391 | static void set_dirty(struct cache *cache, dm_oblock_t oblock, dm_cblock_t cblock) | ||
392 | { | ||
393 | if (!test_and_set_bit(from_cblock(cblock), cache->dirty_bitset)) { | ||
394 | cache->nr_dirty = to_cblock(from_cblock(cache->nr_dirty) + 1); | ||
395 | policy_set_dirty(cache->policy, oblock); | ||
396 | } | ||
397 | } | ||
398 | |||
399 | static void clear_dirty(struct cache *cache, dm_oblock_t oblock, dm_cblock_t cblock) | ||
400 | { | ||
401 | if (test_and_clear_bit(from_cblock(cblock), cache->dirty_bitset)) { | ||
402 | policy_clear_dirty(cache->policy, oblock); | ||
403 | cache->nr_dirty = to_cblock(from_cblock(cache->nr_dirty) - 1); | ||
404 | if (!from_cblock(cache->nr_dirty)) | ||
405 | dm_table_event(cache->ti->table); | ||
406 | } | ||
407 | } | ||
408 | |||
409 | /*----------------------------------------------------------------*/ | ||
410 | static bool block_size_is_power_of_two(struct cache *cache) | ||
411 | { | ||
412 | return cache->sectors_per_block_shift >= 0; | ||
413 | } | ||
414 | |||
415 | static dm_dblock_t oblock_to_dblock(struct cache *cache, dm_oblock_t oblock) | ||
416 | { | ||
417 | sector_t discard_blocks = cache->discard_block_size; | ||
418 | dm_block_t b = from_oblock(oblock); | ||
419 | |||
420 | if (!block_size_is_power_of_two(cache)) | ||
421 | (void) sector_div(discard_blocks, cache->sectors_per_block); | ||
422 | else | ||
423 | discard_blocks >>= cache->sectors_per_block_shift; | ||
424 | |||
425 | (void) sector_div(b, discard_blocks); | ||
426 | |||
427 | return to_dblock(b); | ||
428 | } | ||
429 | |||
430 | static void set_discard(struct cache *cache, dm_dblock_t b) | ||
431 | { | ||
432 | unsigned long flags; | ||
433 | |||
434 | atomic_inc(&cache->stats.discard_count); | ||
435 | |||
436 | spin_lock_irqsave(&cache->lock, flags); | ||
437 | set_bit(from_dblock(b), cache->discard_bitset); | ||
438 | spin_unlock_irqrestore(&cache->lock, flags); | ||
439 | } | ||
440 | |||
441 | static void clear_discard(struct cache *cache, dm_dblock_t b) | ||
442 | { | ||
443 | unsigned long flags; | ||
444 | |||
445 | spin_lock_irqsave(&cache->lock, flags); | ||
446 | clear_bit(from_dblock(b), cache->discard_bitset); | ||
447 | spin_unlock_irqrestore(&cache->lock, flags); | ||
448 | } | ||
449 | |||
450 | static bool is_discarded(struct cache *cache, dm_dblock_t b) | ||
451 | { | ||
452 | int r; | ||
453 | unsigned long flags; | ||
454 | |||
455 | spin_lock_irqsave(&cache->lock, flags); | ||
456 | r = test_bit(from_dblock(b), cache->discard_bitset); | ||
457 | spin_unlock_irqrestore(&cache->lock, flags); | ||
458 | |||
459 | return r; | ||
460 | } | ||
461 | |||
462 | static bool is_discarded_oblock(struct cache *cache, dm_oblock_t b) | ||
463 | { | ||
464 | int r; | ||
465 | unsigned long flags; | ||
466 | |||
467 | spin_lock_irqsave(&cache->lock, flags); | ||
468 | r = test_bit(from_dblock(oblock_to_dblock(cache, b)), | ||
469 | cache->discard_bitset); | ||
470 | spin_unlock_irqrestore(&cache->lock, flags); | ||
471 | |||
472 | return r; | ||
473 | } | ||
474 | |||
475 | /*----------------------------------------------------------------*/ | ||
476 | |||
477 | static void load_stats(struct cache *cache) | ||
478 | { | ||
479 | struct dm_cache_statistics stats; | ||
480 | |||
481 | dm_cache_metadata_get_stats(cache->cmd, &stats); | ||
482 | atomic_set(&cache->stats.read_hit, stats.read_hits); | ||
483 | atomic_set(&cache->stats.read_miss, stats.read_misses); | ||
484 | atomic_set(&cache->stats.write_hit, stats.write_hits); | ||
485 | atomic_set(&cache->stats.write_miss, stats.write_misses); | ||
486 | } | ||
487 | |||
488 | static void save_stats(struct cache *cache) | ||
489 | { | ||
490 | struct dm_cache_statistics stats; | ||
491 | |||
492 | stats.read_hits = atomic_read(&cache->stats.read_hit); | ||
493 | stats.read_misses = atomic_read(&cache->stats.read_miss); | ||
494 | stats.write_hits = atomic_read(&cache->stats.write_hit); | ||
495 | stats.write_misses = atomic_read(&cache->stats.write_miss); | ||
496 | |||
497 | dm_cache_metadata_set_stats(cache->cmd, &stats); | ||
498 | } | ||
499 | |||
500 | /*---------------------------------------------------------------- | ||
501 | * Per bio data | ||
502 | *--------------------------------------------------------------*/ | ||
503 | static struct per_bio_data *get_per_bio_data(struct bio *bio) | ||
504 | { | ||
505 | struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data)); | ||
506 | BUG_ON(!pb); | ||
507 | return pb; | ||
508 | } | ||
509 | |||
510 | static struct per_bio_data *init_per_bio_data(struct bio *bio) | ||
511 | { | ||
512 | struct per_bio_data *pb = get_per_bio_data(bio); | ||
513 | |||
514 | pb->tick = false; | ||
515 | pb->req_nr = dm_bio_get_target_bio_nr(bio); | ||
516 | pb->all_io_entry = NULL; | ||
517 | |||
518 | return pb; | ||
519 | } | ||
520 | |||
521 | /*---------------------------------------------------------------- | ||
522 | * Remapping | ||
523 | *--------------------------------------------------------------*/ | ||
524 | static void remap_to_origin(struct cache *cache, struct bio *bio) | ||
525 | { | ||
526 | bio->bi_bdev = cache->origin_dev->bdev; | ||
527 | } | ||
528 | |||
529 | static void remap_to_cache(struct cache *cache, struct bio *bio, | ||
530 | dm_cblock_t cblock) | ||
531 | { | ||
532 | sector_t bi_sector = bio->bi_sector; | ||
533 | |||
534 | bio->bi_bdev = cache->cache_dev->bdev; | ||
535 | if (!block_size_is_power_of_two(cache)) | ||
536 | bio->bi_sector = (from_cblock(cblock) * cache->sectors_per_block) + | ||
537 | sector_div(bi_sector, cache->sectors_per_block); | ||
538 | else | ||
539 | bio->bi_sector = (from_cblock(cblock) << cache->sectors_per_block_shift) | | ||
540 | (bi_sector & (cache->sectors_per_block - 1)); | ||
541 | } | ||
542 | |||
543 | static void check_if_tick_bio_needed(struct cache *cache, struct bio *bio) | ||
544 | { | ||
545 | unsigned long flags; | ||
546 | struct per_bio_data *pb = get_per_bio_data(bio); | ||
547 | |||
548 | spin_lock_irqsave(&cache->lock, flags); | ||
549 | if (cache->need_tick_bio && | ||
550 | !(bio->bi_rw & (REQ_FUA | REQ_FLUSH | REQ_DISCARD))) { | ||
551 | pb->tick = true; | ||
552 | cache->need_tick_bio = false; | ||
553 | } | ||
554 | spin_unlock_irqrestore(&cache->lock, flags); | ||
555 | } | ||
556 | |||
557 | static void remap_to_origin_clear_discard(struct cache *cache, struct bio *bio, | ||
558 | dm_oblock_t oblock) | ||
559 | { | ||
560 | check_if_tick_bio_needed(cache, bio); | ||
561 | remap_to_origin(cache, bio); | ||
562 | if (bio_data_dir(bio) == WRITE) | ||
563 | clear_discard(cache, oblock_to_dblock(cache, oblock)); | ||
564 | } | ||
565 | |||
566 | static void remap_to_cache_dirty(struct cache *cache, struct bio *bio, | ||
567 | dm_oblock_t oblock, dm_cblock_t cblock) | ||
568 | { | ||
569 | remap_to_cache(cache, bio, cblock); | ||
570 | if (bio_data_dir(bio) == WRITE) { | ||
571 | set_dirty(cache, oblock, cblock); | ||
572 | clear_discard(cache, oblock_to_dblock(cache, oblock)); | ||
573 | } | ||
574 | } | ||
575 | |||
576 | static dm_oblock_t get_bio_block(struct cache *cache, struct bio *bio) | ||
577 | { | ||
578 | sector_t block_nr = bio->bi_sector; | ||
579 | |||
580 | if (!block_size_is_power_of_two(cache)) | ||
581 | (void) sector_div(block_nr, cache->sectors_per_block); | ||
582 | else | ||
583 | block_nr >>= cache->sectors_per_block_shift; | ||
584 | |||
585 | return to_oblock(block_nr); | ||
586 | } | ||
587 | |||
588 | static int bio_triggers_commit(struct cache *cache, struct bio *bio) | ||
589 | { | ||
590 | return bio->bi_rw & (REQ_FLUSH | REQ_FUA); | ||
591 | } | ||
592 | |||
593 | static void issue(struct cache *cache, struct bio *bio) | ||
594 | { | ||
595 | unsigned long flags; | ||
596 | |||
597 | if (!bio_triggers_commit(cache, bio)) { | ||
598 | generic_make_request(bio); | ||
599 | return; | ||
600 | } | ||
601 | |||
602 | /* | ||
603 | * Batch together any bios that trigger commits and then issue a | ||
604 | * single commit for them in do_worker(). | ||
605 | */ | ||
606 | spin_lock_irqsave(&cache->lock, flags); | ||
607 | cache->commit_requested = true; | ||
608 | bio_list_add(&cache->deferred_flush_bios, bio); | ||
609 | spin_unlock_irqrestore(&cache->lock, flags); | ||
610 | } | ||
611 | |||
612 | /*---------------------------------------------------------------- | ||
613 | * Migration processing | ||
614 | * | ||
615 | * Migration covers moving data from the origin device to the cache, or | ||
616 | * vice versa. | ||
617 | *--------------------------------------------------------------*/ | ||
618 | static void free_migration(struct dm_cache_migration *mg) | ||
619 | { | ||
620 | mempool_free(mg, mg->cache->migration_pool); | ||
621 | } | ||
622 | |||
623 | static void inc_nr_migrations(struct cache *cache) | ||
624 | { | ||
625 | atomic_inc(&cache->nr_migrations); | ||
626 | } | ||
627 | |||
628 | static void dec_nr_migrations(struct cache *cache) | ||
629 | { | ||
630 | atomic_dec(&cache->nr_migrations); | ||
631 | |||
632 | /* | ||
633 | * Wake the worker in case we're suspending the target. | ||
634 | */ | ||
635 | wake_up(&cache->migration_wait); | ||
636 | } | ||
637 | |||
638 | static void __cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell, | ||
639 | bool holder) | ||
640 | { | ||
641 | (holder ? dm_cell_release : dm_cell_release_no_holder) | ||
642 | (cache->prison, cell, &cache->deferred_bios); | ||
643 | free_prison_cell(cache, cell); | ||
644 | } | ||
645 | |||
646 | static void cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell, | ||
647 | bool holder) | ||
648 | { | ||
649 | unsigned long flags; | ||
650 | |||
651 | spin_lock_irqsave(&cache->lock, flags); | ||
652 | __cell_defer(cache, cell, holder); | ||
653 | spin_unlock_irqrestore(&cache->lock, flags); | ||
654 | |||
655 | wake_worker(cache); | ||
656 | } | ||
657 | |||
658 | static void cleanup_migration(struct dm_cache_migration *mg) | ||
659 | { | ||
660 | dec_nr_migrations(mg->cache); | ||
661 | free_migration(mg); | ||
662 | } | ||
663 | |||
664 | static void migration_failure(struct dm_cache_migration *mg) | ||
665 | { | ||
666 | struct cache *cache = mg->cache; | ||
667 | |||
668 | if (mg->writeback) { | ||
669 | DMWARN_LIMIT("writeback failed; couldn't copy block"); | ||
670 | set_dirty(cache, mg->old_oblock, mg->cblock); | ||
671 | cell_defer(cache, mg->old_ocell, false); | ||
672 | |||
673 | } else if (mg->demote) { | ||
674 | DMWARN_LIMIT("demotion failed; couldn't copy block"); | ||
675 | policy_force_mapping(cache->policy, mg->new_oblock, mg->old_oblock); | ||
676 | |||
677 | cell_defer(cache, mg->old_ocell, mg->promote ? 0 : 1); | ||
678 | if (mg->promote) | ||
679 | cell_defer(cache, mg->new_ocell, 1); | ||
680 | } else { | ||
681 | DMWARN_LIMIT("promotion failed; couldn't copy block"); | ||
682 | policy_remove_mapping(cache->policy, mg->new_oblock); | ||
683 | cell_defer(cache, mg->new_ocell, 1); | ||
684 | } | ||
685 | |||
686 | cleanup_migration(mg); | ||
687 | } | ||
688 | |||
689 | static void migration_success_pre_commit(struct dm_cache_migration *mg) | ||
690 | { | ||
691 | unsigned long flags; | ||
692 | struct cache *cache = mg->cache; | ||
693 | |||
694 | if (mg->writeback) { | ||
695 | cell_defer(cache, mg->old_ocell, false); | ||
696 | clear_dirty(cache, mg->old_oblock, mg->cblock); | ||
697 | cleanup_migration(mg); | ||
698 | return; | ||
699 | |||
700 | } else if (mg->demote) { | ||
701 | if (dm_cache_remove_mapping(cache->cmd, mg->cblock)) { | ||
702 | DMWARN_LIMIT("demotion failed; couldn't update on disk metadata"); | ||
703 | policy_force_mapping(cache->policy, mg->new_oblock, | ||
704 | mg->old_oblock); | ||
705 | if (mg->promote) | ||
706 | cell_defer(cache, mg->new_ocell, true); | ||
707 | cleanup_migration(mg); | ||
708 | return; | ||
709 | } | ||
710 | } else { | ||
711 | if (dm_cache_insert_mapping(cache->cmd, mg->cblock, mg->new_oblock)) { | ||
712 | DMWARN_LIMIT("promotion failed; couldn't update on disk metadata"); | ||
713 | policy_remove_mapping(cache->policy, mg->new_oblock); | ||
714 | cleanup_migration(mg); | ||
715 | return; | ||
716 | } | ||
717 | } | ||
718 | |||
719 | spin_lock_irqsave(&cache->lock, flags); | ||
720 | list_add_tail(&mg->list, &cache->need_commit_migrations); | ||
721 | cache->commit_requested = true; | ||
722 | spin_unlock_irqrestore(&cache->lock, flags); | ||
723 | } | ||
724 | |||
725 | static void migration_success_post_commit(struct dm_cache_migration *mg) | ||
726 | { | ||
727 | unsigned long flags; | ||
728 | struct cache *cache = mg->cache; | ||
729 | |||
730 | if (mg->writeback) { | ||
731 | DMWARN("writeback unexpectedly triggered commit"); | ||
732 | return; | ||
733 | |||
734 | } else if (mg->demote) { | ||
735 | cell_defer(cache, mg->old_ocell, mg->promote ? 0 : 1); | ||
736 | |||
737 | if (mg->promote) { | ||
738 | mg->demote = false; | ||
739 | |||
740 | spin_lock_irqsave(&cache->lock, flags); | ||
741 | list_add_tail(&mg->list, &cache->quiesced_migrations); | ||
742 | spin_unlock_irqrestore(&cache->lock, flags); | ||
743 | |||
744 | } else | ||
745 | cleanup_migration(mg); | ||
746 | |||
747 | } else { | ||
748 | cell_defer(cache, mg->new_ocell, true); | ||
749 | clear_dirty(cache, mg->new_oblock, mg->cblock); | ||
750 | cleanup_migration(mg); | ||
751 | } | ||
752 | } | ||
753 | |||
754 | static void copy_complete(int read_err, unsigned long write_err, void *context) | ||
755 | { | ||
756 | unsigned long flags; | ||
757 | struct dm_cache_migration *mg = (struct dm_cache_migration *) context; | ||
758 | struct cache *cache = mg->cache; | ||
759 | |||
760 | if (read_err || write_err) | ||
761 | mg->err = true; | ||
762 | |||
763 | spin_lock_irqsave(&cache->lock, flags); | ||
764 | list_add_tail(&mg->list, &cache->completed_migrations); | ||
765 | spin_unlock_irqrestore(&cache->lock, flags); | ||
766 | |||
767 | wake_worker(cache); | ||
768 | } | ||
769 | |||
770 | static void issue_copy_real(struct dm_cache_migration *mg) | ||
771 | { | ||
772 | int r; | ||
773 | struct dm_io_region o_region, c_region; | ||
774 | struct cache *cache = mg->cache; | ||
775 | |||
776 | o_region.bdev = cache->origin_dev->bdev; | ||
777 | o_region.count = cache->sectors_per_block; | ||
778 | |||
779 | c_region.bdev = cache->cache_dev->bdev; | ||
780 | c_region.sector = from_cblock(mg->cblock) * cache->sectors_per_block; | ||
781 | c_region.count = cache->sectors_per_block; | ||
782 | |||
783 | if (mg->writeback || mg->demote) { | ||
784 | /* demote */ | ||
785 | o_region.sector = from_oblock(mg->old_oblock) * cache->sectors_per_block; | ||
786 | r = dm_kcopyd_copy(cache->copier, &c_region, 1, &o_region, 0, copy_complete, mg); | ||
787 | } else { | ||
788 | /* promote */ | ||
789 | o_region.sector = from_oblock(mg->new_oblock) * cache->sectors_per_block; | ||
790 | r = dm_kcopyd_copy(cache->copier, &o_region, 1, &c_region, 0, copy_complete, mg); | ||
791 | } | ||
792 | |||
793 | if (r < 0) | ||
794 | migration_failure(mg); | ||
795 | } | ||
796 | |||
797 | static void avoid_copy(struct dm_cache_migration *mg) | ||
798 | { | ||
799 | atomic_inc(&mg->cache->stats.copies_avoided); | ||
800 | migration_success_pre_commit(mg); | ||
801 | } | ||
802 | |||
803 | static void issue_copy(struct dm_cache_migration *mg) | ||
804 | { | ||
805 | bool avoid; | ||
806 | struct cache *cache = mg->cache; | ||
807 | |||
808 | if (mg->writeback || mg->demote) | ||
809 | avoid = !is_dirty(cache, mg->cblock) || | ||
810 | is_discarded_oblock(cache, mg->old_oblock); | ||
811 | else | ||
812 | avoid = is_discarded_oblock(cache, mg->new_oblock); | ||
813 | |||
814 | avoid ? avoid_copy(mg) : issue_copy_real(mg); | ||
815 | } | ||
816 | |||
817 | static void complete_migration(struct dm_cache_migration *mg) | ||
818 | { | ||
819 | if (mg->err) | ||
820 | migration_failure(mg); | ||
821 | else | ||
822 | migration_success_pre_commit(mg); | ||
823 | } | ||
824 | |||
825 | static void process_migrations(struct cache *cache, struct list_head *head, | ||
826 | void (*fn)(struct dm_cache_migration *)) | ||
827 | { | ||
828 | unsigned long flags; | ||
829 | struct list_head list; | ||
830 | struct dm_cache_migration *mg, *tmp; | ||
831 | |||
832 | INIT_LIST_HEAD(&list); | ||
833 | spin_lock_irqsave(&cache->lock, flags); | ||
834 | list_splice_init(head, &list); | ||
835 | spin_unlock_irqrestore(&cache->lock, flags); | ||
836 | |||
837 | list_for_each_entry_safe(mg, tmp, &list, list) | ||
838 | fn(mg); | ||
839 | } | ||
840 | |||
841 | static void __queue_quiesced_migration(struct dm_cache_migration *mg) | ||
842 | { | ||
843 | list_add_tail(&mg->list, &mg->cache->quiesced_migrations); | ||
844 | } | ||
845 | |||
846 | static void queue_quiesced_migration(struct dm_cache_migration *mg) | ||
847 | { | ||
848 | unsigned long flags; | ||
849 | struct cache *cache = mg->cache; | ||
850 | |||
851 | spin_lock_irqsave(&cache->lock, flags); | ||
852 | __queue_quiesced_migration(mg); | ||
853 | spin_unlock_irqrestore(&cache->lock, flags); | ||
854 | |||
855 | wake_worker(cache); | ||
856 | } | ||
857 | |||
858 | static void queue_quiesced_migrations(struct cache *cache, struct list_head *work) | ||
859 | { | ||
860 | unsigned long flags; | ||
861 | struct dm_cache_migration *mg, *tmp; | ||
862 | |||
863 | spin_lock_irqsave(&cache->lock, flags); | ||
864 | list_for_each_entry_safe(mg, tmp, work, list) | ||
865 | __queue_quiesced_migration(mg); | ||
866 | spin_unlock_irqrestore(&cache->lock, flags); | ||
867 | |||
868 | wake_worker(cache); | ||
869 | } | ||
870 | |||
871 | static void check_for_quiesced_migrations(struct cache *cache, | ||
872 | struct per_bio_data *pb) | ||
873 | { | ||
874 | struct list_head work; | ||
875 | |||
876 | if (!pb->all_io_entry) | ||
877 | return; | ||
878 | |||
879 | INIT_LIST_HEAD(&work); | ||
880 | if (pb->all_io_entry) | ||
881 | dm_deferred_entry_dec(pb->all_io_entry, &work); | ||
882 | |||
883 | if (!list_empty(&work)) | ||
884 | queue_quiesced_migrations(cache, &work); | ||
885 | } | ||
886 | |||
887 | static void quiesce_migration(struct dm_cache_migration *mg) | ||
888 | { | ||
889 | if (!dm_deferred_set_add_work(mg->cache->all_io_ds, &mg->list)) | ||
890 | queue_quiesced_migration(mg); | ||
891 | } | ||
892 | |||
893 | static void promote(struct cache *cache, struct prealloc *structs, | ||
894 | dm_oblock_t oblock, dm_cblock_t cblock, | ||
895 | struct dm_bio_prison_cell *cell) | ||
896 | { | ||
897 | struct dm_cache_migration *mg = prealloc_get_migration(structs); | ||
898 | |||
899 | mg->err = false; | ||
900 | mg->writeback = false; | ||
901 | mg->demote = false; | ||
902 | mg->promote = true; | ||
903 | mg->cache = cache; | ||
904 | mg->new_oblock = oblock; | ||
905 | mg->cblock = cblock; | ||
906 | mg->old_ocell = NULL; | ||
907 | mg->new_ocell = cell; | ||
908 | mg->start_jiffies = jiffies; | ||
909 | |||
910 | inc_nr_migrations(cache); | ||
911 | quiesce_migration(mg); | ||
912 | } | ||
913 | |||
914 | static void writeback(struct cache *cache, struct prealloc *structs, | ||
915 | dm_oblock_t oblock, dm_cblock_t cblock, | ||
916 | struct dm_bio_prison_cell *cell) | ||
917 | { | ||
918 | struct dm_cache_migration *mg = prealloc_get_migration(structs); | ||
919 | |||
920 | mg->err = false; | ||
921 | mg->writeback = true; | ||
922 | mg->demote = false; | ||
923 | mg->promote = false; | ||
924 | mg->cache = cache; | ||
925 | mg->old_oblock = oblock; | ||
926 | mg->cblock = cblock; | ||
927 | mg->old_ocell = cell; | ||
928 | mg->new_ocell = NULL; | ||
929 | mg->start_jiffies = jiffies; | ||
930 | |||
931 | inc_nr_migrations(cache); | ||
932 | quiesce_migration(mg); | ||
933 | } | ||
934 | |||
935 | static void demote_then_promote(struct cache *cache, struct prealloc *structs, | ||
936 | dm_oblock_t old_oblock, dm_oblock_t new_oblock, | ||
937 | dm_cblock_t cblock, | ||
938 | struct dm_bio_prison_cell *old_ocell, | ||
939 | struct dm_bio_prison_cell *new_ocell) | ||
940 | { | ||
941 | struct dm_cache_migration *mg = prealloc_get_migration(structs); | ||
942 | |||
943 | mg->err = false; | ||
944 | mg->writeback = false; | ||
945 | mg->demote = true; | ||
946 | mg->promote = true; | ||
947 | mg->cache = cache; | ||
948 | mg->old_oblock = old_oblock; | ||
949 | mg->new_oblock = new_oblock; | ||
950 | mg->cblock = cblock; | ||
951 | mg->old_ocell = old_ocell; | ||
952 | mg->new_ocell = new_ocell; | ||
953 | mg->start_jiffies = jiffies; | ||
954 | |||
955 | inc_nr_migrations(cache); | ||
956 | quiesce_migration(mg); | ||
957 | } | ||
958 | |||
959 | /*---------------------------------------------------------------- | ||
960 | * bio processing | ||
961 | *--------------------------------------------------------------*/ | ||
962 | static void defer_bio(struct cache *cache, struct bio *bio) | ||
963 | { | ||
964 | unsigned long flags; | ||
965 | |||
966 | spin_lock_irqsave(&cache->lock, flags); | ||
967 | bio_list_add(&cache->deferred_bios, bio); | ||
968 | spin_unlock_irqrestore(&cache->lock, flags); | ||
969 | |||
970 | wake_worker(cache); | ||
971 | } | ||
972 | |||
973 | static void process_flush_bio(struct cache *cache, struct bio *bio) | ||
974 | { | ||
975 | struct per_bio_data *pb = get_per_bio_data(bio); | ||
976 | |||
977 | BUG_ON(bio->bi_size); | ||
978 | if (!pb->req_nr) | ||
979 | remap_to_origin(cache, bio); | ||
980 | else | ||
981 | remap_to_cache(cache, bio, 0); | ||
982 | |||
983 | issue(cache, bio); | ||
984 | } | ||
985 | |||
986 | /* | ||
987 | * People generally discard large parts of a device, eg, the whole device | ||
988 | * when formatting. Splitting these large discards up into cache block | ||
989 | * sized ios and then quiescing (always neccessary for discard) takes too | ||
990 | * long. | ||
991 | * | ||
992 | * We keep it simple, and allow any size of discard to come in, and just | ||
993 | * mark off blocks on the discard bitset. No passdown occurs! | ||
994 | * | ||
995 | * To implement passdown we need to change the bio_prison such that a cell | ||
996 | * can have a key that spans many blocks. | ||
997 | */ | ||
998 | static void process_discard_bio(struct cache *cache, struct bio *bio) | ||
999 | { | ||
1000 | dm_block_t start_block = dm_sector_div_up(bio->bi_sector, | ||
1001 | cache->discard_block_size); | ||
1002 | dm_block_t end_block = bio->bi_sector + bio_sectors(bio); | ||
1003 | dm_block_t b; | ||
1004 | |||
1005 | (void) sector_div(end_block, cache->discard_block_size); | ||
1006 | |||
1007 | for (b = start_block; b < end_block; b++) | ||
1008 | set_discard(cache, to_dblock(b)); | ||
1009 | |||
1010 | bio_endio(bio, 0); | ||
1011 | } | ||
1012 | |||
1013 | static bool spare_migration_bandwidth(struct cache *cache) | ||
1014 | { | ||
1015 | sector_t current_volume = (atomic_read(&cache->nr_migrations) + 1) * | ||
1016 | cache->sectors_per_block; | ||
1017 | return current_volume < cache->migration_threshold; | ||
1018 | } | ||
1019 | |||
1020 | static bool is_writethrough_io(struct cache *cache, struct bio *bio, | ||
1021 | dm_cblock_t cblock) | ||
1022 | { | ||
1023 | return bio_data_dir(bio) == WRITE && | ||
1024 | cache->features.write_through && !is_dirty(cache, cblock); | ||
1025 | } | ||
1026 | |||
1027 | static void inc_hit_counter(struct cache *cache, struct bio *bio) | ||
1028 | { | ||
1029 | atomic_inc(bio_data_dir(bio) == READ ? | ||
1030 | &cache->stats.read_hit : &cache->stats.write_hit); | ||
1031 | } | ||
1032 | |||
1033 | static void inc_miss_counter(struct cache *cache, struct bio *bio) | ||
1034 | { | ||
1035 | atomic_inc(bio_data_dir(bio) == READ ? | ||
1036 | &cache->stats.read_miss : &cache->stats.write_miss); | ||
1037 | } | ||
1038 | |||
1039 | static void process_bio(struct cache *cache, struct prealloc *structs, | ||
1040 | struct bio *bio) | ||
1041 | { | ||
1042 | int r; | ||
1043 | bool release_cell = true; | ||
1044 | dm_oblock_t block = get_bio_block(cache, bio); | ||
1045 | struct dm_bio_prison_cell *cell_prealloc, *old_ocell, *new_ocell; | ||
1046 | struct policy_result lookup_result; | ||
1047 | struct per_bio_data *pb = get_per_bio_data(bio); | ||
1048 | bool discarded_block = is_discarded_oblock(cache, block); | ||
1049 | bool can_migrate = discarded_block || spare_migration_bandwidth(cache); | ||
1050 | |||
1051 | /* | ||
1052 | * Check to see if that block is currently migrating. | ||
1053 | */ | ||
1054 | cell_prealloc = prealloc_get_cell(structs); | ||
1055 | r = bio_detain(cache, block, bio, cell_prealloc, | ||
1056 | (cell_free_fn) prealloc_put_cell, | ||
1057 | structs, &new_ocell); | ||
1058 | if (r > 0) | ||
1059 | return; | ||
1060 | |||
1061 | r = policy_map(cache->policy, block, true, can_migrate, discarded_block, | ||
1062 | bio, &lookup_result); | ||
1063 | |||
1064 | if (r == -EWOULDBLOCK) | ||
1065 | /* migration has been denied */ | ||
1066 | lookup_result.op = POLICY_MISS; | ||
1067 | |||
1068 | switch (lookup_result.op) { | ||
1069 | case POLICY_HIT: | ||
1070 | inc_hit_counter(cache, bio); | ||
1071 | pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); | ||
1072 | |||
1073 | if (is_writethrough_io(cache, bio, lookup_result.cblock)) { | ||
1074 | /* | ||
1075 | * No need to mark anything dirty in write through mode. | ||
1076 | */ | ||
1077 | pb->req_nr == 0 ? | ||
1078 | remap_to_cache(cache, bio, lookup_result.cblock) : | ||
1079 | remap_to_origin_clear_discard(cache, bio, block); | ||
1080 | } else | ||
1081 | remap_to_cache_dirty(cache, bio, block, lookup_result.cblock); | ||
1082 | |||
1083 | issue(cache, bio); | ||
1084 | break; | ||
1085 | |||
1086 | case POLICY_MISS: | ||
1087 | inc_miss_counter(cache, bio); | ||
1088 | pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); | ||
1089 | |||
1090 | if (pb->req_nr != 0) { | ||
1091 | /* | ||
1092 | * This is a duplicate writethrough io that is no | ||
1093 | * longer needed because the block has been demoted. | ||
1094 | */ | ||
1095 | bio_endio(bio, 0); | ||
1096 | } else { | ||
1097 | remap_to_origin_clear_discard(cache, bio, block); | ||
1098 | issue(cache, bio); | ||
1099 | } | ||
1100 | break; | ||
1101 | |||
1102 | case POLICY_NEW: | ||
1103 | atomic_inc(&cache->stats.promotion); | ||
1104 | promote(cache, structs, block, lookup_result.cblock, new_ocell); | ||
1105 | release_cell = false; | ||
1106 | break; | ||
1107 | |||
1108 | case POLICY_REPLACE: | ||
1109 | cell_prealloc = prealloc_get_cell(structs); | ||
1110 | r = bio_detain(cache, lookup_result.old_oblock, bio, cell_prealloc, | ||
1111 | (cell_free_fn) prealloc_put_cell, | ||
1112 | structs, &old_ocell); | ||
1113 | if (r > 0) { | ||
1114 | /* | ||
1115 | * We have to be careful to avoid lock inversion of | ||
1116 | * the cells. So we back off, and wait for the | ||
1117 | * old_ocell to become free. | ||
1118 | */ | ||
1119 | policy_force_mapping(cache->policy, block, | ||
1120 | lookup_result.old_oblock); | ||
1121 | atomic_inc(&cache->stats.cache_cell_clash); | ||
1122 | break; | ||
1123 | } | ||
1124 | atomic_inc(&cache->stats.demotion); | ||
1125 | atomic_inc(&cache->stats.promotion); | ||
1126 | |||
1127 | demote_then_promote(cache, structs, lookup_result.old_oblock, | ||
1128 | block, lookup_result.cblock, | ||
1129 | old_ocell, new_ocell); | ||
1130 | release_cell = false; | ||
1131 | break; | ||
1132 | |||
1133 | default: | ||
1134 | DMERR_LIMIT("%s: erroring bio, unknown policy op: %u", __func__, | ||
1135 | (unsigned) lookup_result.op); | ||
1136 | bio_io_error(bio); | ||
1137 | } | ||
1138 | |||
1139 | if (release_cell) | ||
1140 | cell_defer(cache, new_ocell, false); | ||
1141 | } | ||
1142 | |||
1143 | static int need_commit_due_to_time(struct cache *cache) | ||
1144 | { | ||
1145 | return jiffies < cache->last_commit_jiffies || | ||
1146 | jiffies > cache->last_commit_jiffies + COMMIT_PERIOD; | ||
1147 | } | ||
1148 | |||
1149 | static int commit_if_needed(struct cache *cache) | ||
1150 | { | ||
1151 | if (dm_cache_changed_this_transaction(cache->cmd) && | ||
1152 | (cache->commit_requested || need_commit_due_to_time(cache))) { | ||
1153 | atomic_inc(&cache->stats.commit_count); | ||
1154 | cache->last_commit_jiffies = jiffies; | ||
1155 | cache->commit_requested = false; | ||
1156 | return dm_cache_commit(cache->cmd, false); | ||
1157 | } | ||
1158 | |||
1159 | return 0; | ||
1160 | } | ||
1161 | |||
1162 | static void process_deferred_bios(struct cache *cache) | ||
1163 | { | ||
1164 | unsigned long flags; | ||
1165 | struct bio_list bios; | ||
1166 | struct bio *bio; | ||
1167 | struct prealloc structs; | ||
1168 | |||
1169 | memset(&structs, 0, sizeof(structs)); | ||
1170 | bio_list_init(&bios); | ||
1171 | |||
1172 | spin_lock_irqsave(&cache->lock, flags); | ||
1173 | bio_list_merge(&bios, &cache->deferred_bios); | ||
1174 | bio_list_init(&cache->deferred_bios); | ||
1175 | spin_unlock_irqrestore(&cache->lock, flags); | ||
1176 | |||
1177 | while (!bio_list_empty(&bios)) { | ||
1178 | /* | ||
1179 | * If we've got no free migration structs, and processing | ||
1180 | * this bio might require one, we pause until there are some | ||
1181 | * prepared mappings to process. | ||
1182 | */ | ||
1183 | if (prealloc_data_structs(cache, &structs)) { | ||
1184 | spin_lock_irqsave(&cache->lock, flags); | ||
1185 | bio_list_merge(&cache->deferred_bios, &bios); | ||
1186 | spin_unlock_irqrestore(&cache->lock, flags); | ||
1187 | break; | ||
1188 | } | ||
1189 | |||
1190 | bio = bio_list_pop(&bios); | ||
1191 | |||
1192 | if (bio->bi_rw & REQ_FLUSH) | ||
1193 | process_flush_bio(cache, bio); | ||
1194 | else if (bio->bi_rw & REQ_DISCARD) | ||
1195 | process_discard_bio(cache, bio); | ||
1196 | else | ||
1197 | process_bio(cache, &structs, bio); | ||
1198 | } | ||
1199 | |||
1200 | prealloc_free_structs(cache, &structs); | ||
1201 | } | ||
1202 | |||
1203 | static void process_deferred_flush_bios(struct cache *cache, bool submit_bios) | ||
1204 | { | ||
1205 | unsigned long flags; | ||
1206 | struct bio_list bios; | ||
1207 | struct bio *bio; | ||
1208 | |||
1209 | bio_list_init(&bios); | ||
1210 | |||
1211 | spin_lock_irqsave(&cache->lock, flags); | ||
1212 | bio_list_merge(&bios, &cache->deferred_flush_bios); | ||
1213 | bio_list_init(&cache->deferred_flush_bios); | ||
1214 | spin_unlock_irqrestore(&cache->lock, flags); | ||
1215 | |||
1216 | while ((bio = bio_list_pop(&bios))) | ||
1217 | submit_bios ? generic_make_request(bio) : bio_io_error(bio); | ||
1218 | } | ||
1219 | |||
1220 | static void writeback_some_dirty_blocks(struct cache *cache) | ||
1221 | { | ||
1222 | int r = 0; | ||
1223 | dm_oblock_t oblock; | ||
1224 | dm_cblock_t cblock; | ||
1225 | struct prealloc structs; | ||
1226 | struct dm_bio_prison_cell *old_ocell; | ||
1227 | |||
1228 | memset(&structs, 0, sizeof(structs)); | ||
1229 | |||
1230 | while (spare_migration_bandwidth(cache)) { | ||
1231 | if (prealloc_data_structs(cache, &structs)) | ||
1232 | break; | ||
1233 | |||
1234 | r = policy_writeback_work(cache->policy, &oblock, &cblock); | ||
1235 | if (r) | ||
1236 | break; | ||
1237 | |||
1238 | r = get_cell(cache, oblock, &structs, &old_ocell); | ||
1239 | if (r) { | ||
1240 | policy_set_dirty(cache->policy, oblock); | ||
1241 | break; | ||
1242 | } | ||
1243 | |||
1244 | writeback(cache, &structs, oblock, cblock, old_ocell); | ||
1245 | } | ||
1246 | |||
1247 | prealloc_free_structs(cache, &structs); | ||
1248 | } | ||
1249 | |||
1250 | /*---------------------------------------------------------------- | ||
1251 | * Main worker loop | ||
1252 | *--------------------------------------------------------------*/ | ||
1253 | static void start_quiescing(struct cache *cache) | ||
1254 | { | ||
1255 | unsigned long flags; | ||
1256 | |||
1257 | spin_lock_irqsave(&cache->lock, flags); | ||
1258 | cache->quiescing = 1; | ||
1259 | spin_unlock_irqrestore(&cache->lock, flags); | ||
1260 | } | ||
1261 | |||
1262 | static void stop_quiescing(struct cache *cache) | ||
1263 | { | ||
1264 | unsigned long flags; | ||
1265 | |||
1266 | spin_lock_irqsave(&cache->lock, flags); | ||
1267 | cache->quiescing = 0; | ||
1268 | spin_unlock_irqrestore(&cache->lock, flags); | ||
1269 | } | ||
1270 | |||
1271 | static bool is_quiescing(struct cache *cache) | ||
1272 | { | ||
1273 | int r; | ||
1274 | unsigned long flags; | ||
1275 | |||
1276 | spin_lock_irqsave(&cache->lock, flags); | ||
1277 | r = cache->quiescing; | ||
1278 | spin_unlock_irqrestore(&cache->lock, flags); | ||
1279 | |||
1280 | return r; | ||
1281 | } | ||
1282 | |||
1283 | static void wait_for_migrations(struct cache *cache) | ||
1284 | { | ||
1285 | wait_event(cache->migration_wait, !atomic_read(&cache->nr_migrations)); | ||
1286 | } | ||
1287 | |||
1288 | static void stop_worker(struct cache *cache) | ||
1289 | { | ||
1290 | cancel_delayed_work(&cache->waker); | ||
1291 | flush_workqueue(cache->wq); | ||
1292 | } | ||
1293 | |||
1294 | static void requeue_deferred_io(struct cache *cache) | ||
1295 | { | ||
1296 | struct bio *bio; | ||
1297 | struct bio_list bios; | ||
1298 | |||
1299 | bio_list_init(&bios); | ||
1300 | bio_list_merge(&bios, &cache->deferred_bios); | ||
1301 | bio_list_init(&cache->deferred_bios); | ||
1302 | |||
1303 | while ((bio = bio_list_pop(&bios))) | ||
1304 | bio_endio(bio, DM_ENDIO_REQUEUE); | ||
1305 | } | ||
1306 | |||
1307 | static int more_work(struct cache *cache) | ||
1308 | { | ||
1309 | if (is_quiescing(cache)) | ||
1310 | return !list_empty(&cache->quiesced_migrations) || | ||
1311 | !list_empty(&cache->completed_migrations) || | ||
1312 | !list_empty(&cache->need_commit_migrations); | ||
1313 | else | ||
1314 | return !bio_list_empty(&cache->deferred_bios) || | ||
1315 | !bio_list_empty(&cache->deferred_flush_bios) || | ||
1316 | !list_empty(&cache->quiesced_migrations) || | ||
1317 | !list_empty(&cache->completed_migrations) || | ||
1318 | !list_empty(&cache->need_commit_migrations); | ||
1319 | } | ||
1320 | |||
1321 | static void do_worker(struct work_struct *ws) | ||
1322 | { | ||
1323 | struct cache *cache = container_of(ws, struct cache, worker); | ||
1324 | |||
1325 | do { | ||
1326 | if (!is_quiescing(cache)) | ||
1327 | process_deferred_bios(cache); | ||
1328 | |||
1329 | process_migrations(cache, &cache->quiesced_migrations, issue_copy); | ||
1330 | process_migrations(cache, &cache->completed_migrations, complete_migration); | ||
1331 | |||
1332 | writeback_some_dirty_blocks(cache); | ||
1333 | |||
1334 | if (commit_if_needed(cache)) { | ||
1335 | process_deferred_flush_bios(cache, false); | ||
1336 | |||
1337 | /* | ||
1338 | * FIXME: rollback metadata or just go into a | ||
1339 | * failure mode and error everything | ||
1340 | */ | ||
1341 | } else { | ||
1342 | process_deferred_flush_bios(cache, true); | ||
1343 | process_migrations(cache, &cache->need_commit_migrations, | ||
1344 | migration_success_post_commit); | ||
1345 | } | ||
1346 | } while (more_work(cache)); | ||
1347 | } | ||
1348 | |||
1349 | /* | ||
1350 | * We want to commit periodically so that not too much | ||
1351 | * unwritten metadata builds up. | ||
1352 | */ | ||
1353 | static void do_waker(struct work_struct *ws) | ||
1354 | { | ||
1355 | struct cache *cache = container_of(to_delayed_work(ws), struct cache, waker); | ||
1356 | wake_worker(cache); | ||
1357 | queue_delayed_work(cache->wq, &cache->waker, COMMIT_PERIOD); | ||
1358 | } | ||
1359 | |||
1360 | /*----------------------------------------------------------------*/ | ||
1361 | |||
1362 | static int is_congested(struct dm_dev *dev, int bdi_bits) | ||
1363 | { | ||
1364 | struct request_queue *q = bdev_get_queue(dev->bdev); | ||
1365 | return bdi_congested(&q->backing_dev_info, bdi_bits); | ||
1366 | } | ||
1367 | |||
1368 | static int cache_is_congested(struct dm_target_callbacks *cb, int bdi_bits) | ||
1369 | { | ||
1370 | struct cache *cache = container_of(cb, struct cache, callbacks); | ||
1371 | |||
1372 | return is_congested(cache->origin_dev, bdi_bits) || | ||
1373 | is_congested(cache->cache_dev, bdi_bits); | ||
1374 | } | ||
1375 | |||
1376 | /*---------------------------------------------------------------- | ||
1377 | * Target methods | ||
1378 | *--------------------------------------------------------------*/ | ||
1379 | |||
1380 | /* | ||
1381 | * This function gets called on the error paths of the constructor, so we | ||
1382 | * have to cope with a partially initialised struct. | ||
1383 | */ | ||
1384 | static void destroy(struct cache *cache) | ||
1385 | { | ||
1386 | unsigned i; | ||
1387 | |||
1388 | if (cache->next_migration) | ||
1389 | mempool_free(cache->next_migration, cache->migration_pool); | ||
1390 | |||
1391 | if (cache->migration_pool) | ||
1392 | mempool_destroy(cache->migration_pool); | ||
1393 | |||
1394 | if (cache->all_io_ds) | ||
1395 | dm_deferred_set_destroy(cache->all_io_ds); | ||
1396 | |||
1397 | if (cache->prison) | ||
1398 | dm_bio_prison_destroy(cache->prison); | ||
1399 | |||
1400 | if (cache->wq) | ||
1401 | destroy_workqueue(cache->wq); | ||
1402 | |||
1403 | if (cache->dirty_bitset) | ||
1404 | free_bitset(cache->dirty_bitset); | ||
1405 | |||
1406 | if (cache->discard_bitset) | ||
1407 | free_bitset(cache->discard_bitset); | ||
1408 | |||
1409 | if (cache->copier) | ||
1410 | dm_kcopyd_client_destroy(cache->copier); | ||
1411 | |||
1412 | if (cache->cmd) | ||
1413 | dm_cache_metadata_close(cache->cmd); | ||
1414 | |||
1415 | if (cache->metadata_dev) | ||
1416 | dm_put_device(cache->ti, cache->metadata_dev); | ||
1417 | |||
1418 | if (cache->origin_dev) | ||
1419 | dm_put_device(cache->ti, cache->origin_dev); | ||
1420 | |||
1421 | if (cache->cache_dev) | ||
1422 | dm_put_device(cache->ti, cache->cache_dev); | ||
1423 | |||
1424 | if (cache->policy) | ||
1425 | dm_cache_policy_destroy(cache->policy); | ||
1426 | |||
1427 | for (i = 0; i < cache->nr_ctr_args ; i++) | ||
1428 | kfree(cache->ctr_args[i]); | ||
1429 | kfree(cache->ctr_args); | ||
1430 | |||
1431 | kfree(cache); | ||
1432 | } | ||
1433 | |||
1434 | static void cache_dtr(struct dm_target *ti) | ||
1435 | { | ||
1436 | struct cache *cache = ti->private; | ||
1437 | |||
1438 | destroy(cache); | ||
1439 | } | ||
1440 | |||
1441 | static sector_t get_dev_size(struct dm_dev *dev) | ||
1442 | { | ||
1443 | return i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT; | ||
1444 | } | ||
1445 | |||
1446 | /*----------------------------------------------------------------*/ | ||
1447 | |||
1448 | /* | ||
1449 | * Construct a cache device mapping. | ||
1450 | * | ||
1451 | * cache <metadata dev> <cache dev> <origin dev> <block size> | ||
1452 | * <#feature args> [<feature arg>]* | ||
1453 | * <policy> <#policy args> [<policy arg>]* | ||
1454 | * | ||
1455 | * metadata dev : fast device holding the persistent metadata | ||
1456 | * cache dev : fast device holding cached data blocks | ||
1457 | * origin dev : slow device holding original data blocks | ||
1458 | * block size : cache unit size in sectors | ||
1459 | * | ||
1460 | * #feature args : number of feature arguments passed | ||
1461 | * feature args : writethrough. (The default is writeback.) | ||
1462 | * | ||
1463 | * policy : the replacement policy to use | ||
1464 | * #policy args : an even number of policy arguments corresponding | ||
1465 | * to key/value pairs passed to the policy | ||
1466 | * policy args : key/value pairs passed to the policy | ||
1467 | * E.g. 'sequential_threshold 1024' | ||
1468 | * See cache-policies.txt for details. | ||
1469 | * | ||
1470 | * Optional feature arguments are: | ||
1471 | * writethrough : write through caching that prohibits cache block | ||
1472 | * content from being different from origin block content. | ||
1473 | * Without this argument, the default behaviour is to write | ||
1474 | * back cache block contents later for performance reasons, | ||
1475 | * so they may differ from the corresponding origin blocks. | ||
1476 | */ | ||
1477 | struct cache_args { | ||
1478 | struct dm_target *ti; | ||
1479 | |||
1480 | struct dm_dev *metadata_dev; | ||
1481 | |||
1482 | struct dm_dev *cache_dev; | ||
1483 | sector_t cache_sectors; | ||
1484 | |||
1485 | struct dm_dev *origin_dev; | ||
1486 | sector_t origin_sectors; | ||
1487 | |||
1488 | uint32_t block_size; | ||
1489 | |||
1490 | const char *policy_name; | ||
1491 | int policy_argc; | ||
1492 | const char **policy_argv; | ||
1493 | |||
1494 | struct cache_features features; | ||
1495 | }; | ||
1496 | |||
1497 | static void destroy_cache_args(struct cache_args *ca) | ||
1498 | { | ||
1499 | if (ca->metadata_dev) | ||
1500 | dm_put_device(ca->ti, ca->metadata_dev); | ||
1501 | |||
1502 | if (ca->cache_dev) | ||
1503 | dm_put_device(ca->ti, ca->cache_dev); | ||
1504 | |||
1505 | if (ca->origin_dev) | ||
1506 | dm_put_device(ca->ti, ca->origin_dev); | ||
1507 | |||
1508 | kfree(ca); | ||
1509 | } | ||
1510 | |||
1511 | static bool at_least_one_arg(struct dm_arg_set *as, char **error) | ||
1512 | { | ||
1513 | if (!as->argc) { | ||
1514 | *error = "Insufficient args"; | ||
1515 | return false; | ||
1516 | } | ||
1517 | |||
1518 | return true; | ||
1519 | } | ||
1520 | |||
1521 | static int parse_metadata_dev(struct cache_args *ca, struct dm_arg_set *as, | ||
1522 | char **error) | ||
1523 | { | ||
1524 | int r; | ||
1525 | sector_t metadata_dev_size; | ||
1526 | char b[BDEVNAME_SIZE]; | ||
1527 | |||
1528 | if (!at_least_one_arg(as, error)) | ||
1529 | return -EINVAL; | ||
1530 | |||
1531 | r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE, | ||
1532 | &ca->metadata_dev); | ||
1533 | if (r) { | ||
1534 | *error = "Error opening metadata device"; | ||
1535 | return r; | ||
1536 | } | ||
1537 | |||
1538 | metadata_dev_size = get_dev_size(ca->metadata_dev); | ||
1539 | if (metadata_dev_size > DM_CACHE_METADATA_MAX_SECTORS_WARNING) | ||
1540 | DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.", | ||
1541 | bdevname(ca->metadata_dev->bdev, b), THIN_METADATA_MAX_SECTORS); | ||
1542 | |||
1543 | return 0; | ||
1544 | } | ||
1545 | |||
1546 | static int parse_cache_dev(struct cache_args *ca, struct dm_arg_set *as, | ||
1547 | char **error) | ||
1548 | { | ||
1549 | int r; | ||
1550 | |||
1551 | if (!at_least_one_arg(as, error)) | ||
1552 | return -EINVAL; | ||
1553 | |||
1554 | r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE, | ||
1555 | &ca->cache_dev); | ||
1556 | if (r) { | ||
1557 | *error = "Error opening cache device"; | ||
1558 | return r; | ||
1559 | } | ||
1560 | ca->cache_sectors = get_dev_size(ca->cache_dev); | ||
1561 | |||
1562 | return 0; | ||
1563 | } | ||
1564 | |||
1565 | static int parse_origin_dev(struct cache_args *ca, struct dm_arg_set *as, | ||
1566 | char **error) | ||
1567 | { | ||
1568 | int r; | ||
1569 | |||
1570 | if (!at_least_one_arg(as, error)) | ||
1571 | return -EINVAL; | ||
1572 | |||
1573 | r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE, | ||
1574 | &ca->origin_dev); | ||
1575 | if (r) { | ||
1576 | *error = "Error opening origin device"; | ||
1577 | return r; | ||
1578 | } | ||
1579 | |||
1580 | ca->origin_sectors = get_dev_size(ca->origin_dev); | ||
1581 | if (ca->ti->len > ca->origin_sectors) { | ||
1582 | *error = "Device size larger than cached device"; | ||
1583 | return -EINVAL; | ||
1584 | } | ||
1585 | |||
1586 | return 0; | ||
1587 | } | ||
1588 | |||
1589 | static int parse_block_size(struct cache_args *ca, struct dm_arg_set *as, | ||
1590 | char **error) | ||
1591 | { | ||
1592 | unsigned long tmp; | ||
1593 | |||
1594 | if (!at_least_one_arg(as, error)) | ||
1595 | return -EINVAL; | ||
1596 | |||
1597 | if (kstrtoul(dm_shift_arg(as), 10, &tmp) || !tmp || | ||
1598 | tmp < DATA_DEV_BLOCK_SIZE_MIN_SECTORS || | ||
1599 | tmp & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) { | ||
1600 | *error = "Invalid data block size"; | ||
1601 | return -EINVAL; | ||
1602 | } | ||
1603 | |||
1604 | if (tmp > ca->cache_sectors) { | ||
1605 | *error = "Data block size is larger than the cache device"; | ||
1606 | return -EINVAL; | ||
1607 | } | ||
1608 | |||
1609 | ca->block_size = tmp; | ||
1610 | |||
1611 | return 0; | ||
1612 | } | ||
1613 | |||
1614 | static void init_features(struct cache_features *cf) | ||
1615 | { | ||
1616 | cf->mode = CM_WRITE; | ||
1617 | cf->write_through = false; | ||
1618 | } | ||
1619 | |||
1620 | static int parse_features(struct cache_args *ca, struct dm_arg_set *as, | ||
1621 | char **error) | ||
1622 | { | ||
1623 | static struct dm_arg _args[] = { | ||
1624 | {0, 1, "Invalid number of cache feature arguments"}, | ||
1625 | }; | ||
1626 | |||
1627 | int r; | ||
1628 | unsigned argc; | ||
1629 | const char *arg; | ||
1630 | struct cache_features *cf = &ca->features; | ||
1631 | |||
1632 | init_features(cf); | ||
1633 | |||
1634 | r = dm_read_arg_group(_args, as, &argc, error); | ||
1635 | if (r) | ||
1636 | return -EINVAL; | ||
1637 | |||
1638 | while (argc--) { | ||
1639 | arg = dm_shift_arg(as); | ||
1640 | |||
1641 | if (!strcasecmp(arg, "writeback")) | ||
1642 | cf->write_through = false; | ||
1643 | |||
1644 | else if (!strcasecmp(arg, "writethrough")) | ||
1645 | cf->write_through = true; | ||
1646 | |||
1647 | else { | ||
1648 | *error = "Unrecognised cache feature requested"; | ||
1649 | return -EINVAL; | ||
1650 | } | ||
1651 | } | ||
1652 | |||
1653 | return 0; | ||
1654 | } | ||
1655 | |||
1656 | static int parse_policy(struct cache_args *ca, struct dm_arg_set *as, | ||
1657 | char **error) | ||
1658 | { | ||
1659 | static struct dm_arg _args[] = { | ||
1660 | {0, 1024, "Invalid number of policy arguments"}, | ||
1661 | }; | ||
1662 | |||
1663 | int r; | ||
1664 | |||
1665 | if (!at_least_one_arg(as, error)) | ||
1666 | return -EINVAL; | ||
1667 | |||
1668 | ca->policy_name = dm_shift_arg(as); | ||
1669 | |||
1670 | r = dm_read_arg_group(_args, as, &ca->policy_argc, error); | ||
1671 | if (r) | ||
1672 | return -EINVAL; | ||
1673 | |||
1674 | ca->policy_argv = (const char **)as->argv; | ||
1675 | dm_consume_args(as, ca->policy_argc); | ||
1676 | |||
1677 | return 0; | ||
1678 | } | ||
1679 | |||
1680 | static int parse_cache_args(struct cache_args *ca, int argc, char **argv, | ||
1681 | char **error) | ||
1682 | { | ||
1683 | int r; | ||
1684 | struct dm_arg_set as; | ||
1685 | |||
1686 | as.argc = argc; | ||
1687 | as.argv = argv; | ||
1688 | |||
1689 | r = parse_metadata_dev(ca, &as, error); | ||
1690 | if (r) | ||
1691 | return r; | ||
1692 | |||
1693 | r = parse_cache_dev(ca, &as, error); | ||
1694 | if (r) | ||
1695 | return r; | ||
1696 | |||
1697 | r = parse_origin_dev(ca, &as, error); | ||
1698 | if (r) | ||
1699 | return r; | ||
1700 | |||
1701 | r = parse_block_size(ca, &as, error); | ||
1702 | if (r) | ||
1703 | return r; | ||
1704 | |||
1705 | r = parse_features(ca, &as, error); | ||
1706 | if (r) | ||
1707 | return r; | ||
1708 | |||
1709 | r = parse_policy(ca, &as, error); | ||
1710 | if (r) | ||
1711 | return r; | ||
1712 | |||
1713 | return 0; | ||
1714 | } | ||
1715 | |||
1716 | /*----------------------------------------------------------------*/ | ||
1717 | |||
1718 | static struct kmem_cache *migration_cache; | ||
1719 | |||
1720 | static int set_config_values(struct dm_cache_policy *p, int argc, const char **argv) | ||
1721 | { | ||
1722 | int r = 0; | ||
1723 | |||
1724 | if (argc & 1) { | ||
1725 | DMWARN("Odd number of policy arguments given but they should be <key> <value> pairs."); | ||
1726 | return -EINVAL; | ||
1727 | } | ||
1728 | |||
1729 | while (argc) { | ||
1730 | r = policy_set_config_value(p, argv[0], argv[1]); | ||
1731 | if (r) { | ||
1732 | DMWARN("policy_set_config_value failed: key = '%s', value = '%s'", | ||
1733 | argv[0], argv[1]); | ||
1734 | return r; | ||
1735 | } | ||
1736 | |||
1737 | argc -= 2; | ||
1738 | argv += 2; | ||
1739 | } | ||
1740 | |||
1741 | return r; | ||
1742 | } | ||
1743 | |||
1744 | static int create_cache_policy(struct cache *cache, struct cache_args *ca, | ||
1745 | char **error) | ||
1746 | { | ||
1747 | int r; | ||
1748 | |||
1749 | cache->policy = dm_cache_policy_create(ca->policy_name, | ||
1750 | cache->cache_size, | ||
1751 | cache->origin_sectors, | ||
1752 | cache->sectors_per_block); | ||
1753 | if (!cache->policy) { | ||
1754 | *error = "Error creating cache's policy"; | ||
1755 | return -ENOMEM; | ||
1756 | } | ||
1757 | |||
1758 | r = set_config_values(cache->policy, ca->policy_argc, ca->policy_argv); | ||
1759 | if (r) | ||
1760 | dm_cache_policy_destroy(cache->policy); | ||
1761 | |||
1762 | return r; | ||
1763 | } | ||
1764 | |||
1765 | /* | ||
1766 | * We want the discard block size to be a power of two, at least the size | ||
1767 | * of the cache block size, and have no more than 2^14 discard blocks | ||
1768 | * across the origin. | ||
1769 | */ | ||
1770 | #define MAX_DISCARD_BLOCKS (1 << 14) | ||
1771 | |||
1772 | static bool too_many_discard_blocks(sector_t discard_block_size, | ||
1773 | sector_t origin_size) | ||
1774 | { | ||
1775 | (void) sector_div(origin_size, discard_block_size); | ||
1776 | |||
1777 | return origin_size > MAX_DISCARD_BLOCKS; | ||
1778 | } | ||
1779 | |||
1780 | static sector_t calculate_discard_block_size(sector_t cache_block_size, | ||
1781 | sector_t origin_size) | ||
1782 | { | ||
1783 | sector_t discard_block_size; | ||
1784 | |||
1785 | discard_block_size = roundup_pow_of_two(cache_block_size); | ||
1786 | |||
1787 | if (origin_size) | ||
1788 | while (too_many_discard_blocks(discard_block_size, origin_size)) | ||
1789 | discard_block_size *= 2; | ||
1790 | |||
1791 | return discard_block_size; | ||
1792 | } | ||
1793 | |||
1794 | #define DEFAULT_MIGRATION_THRESHOLD (2048 * 100) | ||
1795 | |||
1796 | static unsigned cache_num_write_bios(struct dm_target *ti, struct bio *bio); | ||
1797 | |||
1798 | static int cache_create(struct cache_args *ca, struct cache **result) | ||
1799 | { | ||
1800 | int r = 0; | ||
1801 | char **error = &ca->ti->error; | ||
1802 | struct cache *cache; | ||
1803 | struct dm_target *ti = ca->ti; | ||
1804 | dm_block_t origin_blocks; | ||
1805 | struct dm_cache_metadata *cmd; | ||
1806 | bool may_format = ca->features.mode == CM_WRITE; | ||
1807 | |||
1808 | cache = kzalloc(sizeof(*cache), GFP_KERNEL); | ||
1809 | if (!cache) | ||
1810 | return -ENOMEM; | ||
1811 | |||
1812 | cache->ti = ca->ti; | ||
1813 | ti->private = cache; | ||
1814 | ti->per_bio_data_size = sizeof(struct per_bio_data); | ||
1815 | ti->num_flush_bios = 2; | ||
1816 | ti->flush_supported = true; | ||
1817 | |||
1818 | ti->num_discard_bios = 1; | ||
1819 | ti->discards_supported = true; | ||
1820 | ti->discard_zeroes_data_unsupported = true; | ||
1821 | |||
1822 | memcpy(&cache->features, &ca->features, sizeof(cache->features)); | ||
1823 | |||
1824 | if (cache->features.write_through) | ||
1825 | ti->num_write_bios = cache_num_write_bios; | ||
1826 | |||
1827 | cache->callbacks.congested_fn = cache_is_congested; | ||
1828 | dm_table_add_target_callbacks(ti->table, &cache->callbacks); | ||
1829 | |||
1830 | cache->metadata_dev = ca->metadata_dev; | ||
1831 | cache->origin_dev = ca->origin_dev; | ||
1832 | cache->cache_dev = ca->cache_dev; | ||
1833 | |||
1834 | ca->metadata_dev = ca->origin_dev = ca->cache_dev = NULL; | ||
1835 | |||
1836 | /* FIXME: factor out this whole section */ | ||
1837 | origin_blocks = cache->origin_sectors = ca->origin_sectors; | ||
1838 | (void) sector_div(origin_blocks, ca->block_size); | ||
1839 | cache->origin_blocks = to_oblock(origin_blocks); | ||
1840 | |||
1841 | cache->sectors_per_block = ca->block_size; | ||
1842 | if (dm_set_target_max_io_len(ti, cache->sectors_per_block)) { | ||
1843 | r = -EINVAL; | ||
1844 | goto bad; | ||
1845 | } | ||
1846 | |||
1847 | if (ca->block_size & (ca->block_size - 1)) { | ||
1848 | dm_block_t cache_size = ca->cache_sectors; | ||
1849 | |||
1850 | cache->sectors_per_block_shift = -1; | ||
1851 | (void) sector_div(cache_size, ca->block_size); | ||
1852 | cache->cache_size = to_cblock(cache_size); | ||
1853 | } else { | ||
1854 | cache->sectors_per_block_shift = __ffs(ca->block_size); | ||
1855 | cache->cache_size = to_cblock(ca->cache_sectors >> cache->sectors_per_block_shift); | ||
1856 | } | ||
1857 | |||
1858 | r = create_cache_policy(cache, ca, error); | ||
1859 | if (r) | ||
1860 | goto bad; | ||
1861 | cache->policy_nr_args = ca->policy_argc; | ||
1862 | |||
1863 | cmd = dm_cache_metadata_open(cache->metadata_dev->bdev, | ||
1864 | ca->block_size, may_format, | ||
1865 | dm_cache_policy_get_hint_size(cache->policy)); | ||
1866 | if (IS_ERR(cmd)) { | ||
1867 | *error = "Error creating metadata object"; | ||
1868 | r = PTR_ERR(cmd); | ||
1869 | goto bad; | ||
1870 | } | ||
1871 | cache->cmd = cmd; | ||
1872 | |||
1873 | spin_lock_init(&cache->lock); | ||
1874 | bio_list_init(&cache->deferred_bios); | ||
1875 | bio_list_init(&cache->deferred_flush_bios); | ||
1876 | INIT_LIST_HEAD(&cache->quiesced_migrations); | ||
1877 | INIT_LIST_HEAD(&cache->completed_migrations); | ||
1878 | INIT_LIST_HEAD(&cache->need_commit_migrations); | ||
1879 | cache->migration_threshold = DEFAULT_MIGRATION_THRESHOLD; | ||
1880 | atomic_set(&cache->nr_migrations, 0); | ||
1881 | init_waitqueue_head(&cache->migration_wait); | ||
1882 | |||
1883 | cache->nr_dirty = 0; | ||
1884 | cache->dirty_bitset = alloc_bitset(from_cblock(cache->cache_size)); | ||
1885 | if (!cache->dirty_bitset) { | ||
1886 | *error = "could not allocate dirty bitset"; | ||
1887 | goto bad; | ||
1888 | } | ||
1889 | clear_bitset(cache->dirty_bitset, from_cblock(cache->cache_size)); | ||
1890 | |||
1891 | cache->discard_block_size = | ||
1892 | calculate_discard_block_size(cache->sectors_per_block, | ||
1893 | cache->origin_sectors); | ||
1894 | cache->discard_nr_blocks = oblock_to_dblock(cache, cache->origin_blocks); | ||
1895 | cache->discard_bitset = alloc_bitset(from_dblock(cache->discard_nr_blocks)); | ||
1896 | if (!cache->discard_bitset) { | ||
1897 | *error = "could not allocate discard bitset"; | ||
1898 | goto bad; | ||
1899 | } | ||
1900 | clear_bitset(cache->discard_bitset, from_dblock(cache->discard_nr_blocks)); | ||
1901 | |||
1902 | cache->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle); | ||
1903 | if (IS_ERR(cache->copier)) { | ||
1904 | *error = "could not create kcopyd client"; | ||
1905 | r = PTR_ERR(cache->copier); | ||
1906 | goto bad; | ||
1907 | } | ||
1908 | |||
1909 | cache->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM); | ||
1910 | if (!cache->wq) { | ||
1911 | *error = "could not create workqueue for metadata object"; | ||
1912 | goto bad; | ||
1913 | } | ||
1914 | INIT_WORK(&cache->worker, do_worker); | ||
1915 | INIT_DELAYED_WORK(&cache->waker, do_waker); | ||
1916 | cache->last_commit_jiffies = jiffies; | ||
1917 | |||
1918 | cache->prison = dm_bio_prison_create(PRISON_CELLS); | ||
1919 | if (!cache->prison) { | ||
1920 | *error = "could not create bio prison"; | ||
1921 | goto bad; | ||
1922 | } | ||
1923 | |||
1924 | cache->all_io_ds = dm_deferred_set_create(); | ||
1925 | if (!cache->all_io_ds) { | ||
1926 | *error = "could not create all_io deferred set"; | ||
1927 | goto bad; | ||
1928 | } | ||
1929 | |||
1930 | cache->migration_pool = mempool_create_slab_pool(MIGRATION_POOL_SIZE, | ||
1931 | migration_cache); | ||
1932 | if (!cache->migration_pool) { | ||
1933 | *error = "Error creating cache's migration mempool"; | ||
1934 | goto bad; | ||
1935 | } | ||
1936 | |||
1937 | cache->next_migration = NULL; | ||
1938 | |||
1939 | cache->need_tick_bio = true; | ||
1940 | cache->sized = false; | ||
1941 | cache->quiescing = false; | ||
1942 | cache->commit_requested = false; | ||
1943 | cache->loaded_mappings = false; | ||
1944 | cache->loaded_discards = false; | ||
1945 | |||
1946 | load_stats(cache); | ||
1947 | |||
1948 | atomic_set(&cache->stats.demotion, 0); | ||
1949 | atomic_set(&cache->stats.promotion, 0); | ||
1950 | atomic_set(&cache->stats.copies_avoided, 0); | ||
1951 | atomic_set(&cache->stats.cache_cell_clash, 0); | ||
1952 | atomic_set(&cache->stats.commit_count, 0); | ||
1953 | atomic_set(&cache->stats.discard_count, 0); | ||
1954 | |||
1955 | *result = cache; | ||
1956 | return 0; | ||
1957 | |||
1958 | bad: | ||
1959 | destroy(cache); | ||
1960 | return r; | ||
1961 | } | ||
1962 | |||
1963 | static int copy_ctr_args(struct cache *cache, int argc, const char **argv) | ||
1964 | { | ||
1965 | unsigned i; | ||
1966 | const char **copy; | ||
1967 | |||
1968 | copy = kcalloc(argc, sizeof(*copy), GFP_KERNEL); | ||
1969 | if (!copy) | ||
1970 | return -ENOMEM; | ||
1971 | for (i = 0; i < argc; i++) { | ||
1972 | copy[i] = kstrdup(argv[i], GFP_KERNEL); | ||
1973 | if (!copy[i]) { | ||
1974 | while (i--) | ||
1975 | kfree(copy[i]); | ||
1976 | kfree(copy); | ||
1977 | return -ENOMEM; | ||
1978 | } | ||
1979 | } | ||
1980 | |||
1981 | cache->nr_ctr_args = argc; | ||
1982 | cache->ctr_args = copy; | ||
1983 | |||
1984 | return 0; | ||
1985 | } | ||
1986 | |||
1987 | static int cache_ctr(struct dm_target *ti, unsigned argc, char **argv) | ||
1988 | { | ||
1989 | int r = -EINVAL; | ||
1990 | struct cache_args *ca; | ||
1991 | struct cache *cache = NULL; | ||
1992 | |||
1993 | ca = kzalloc(sizeof(*ca), GFP_KERNEL); | ||
1994 | if (!ca) { | ||
1995 | ti->error = "Error allocating memory for cache"; | ||
1996 | return -ENOMEM; | ||
1997 | } | ||
1998 | ca->ti = ti; | ||
1999 | |||
2000 | r = parse_cache_args(ca, argc, argv, &ti->error); | ||
2001 | if (r) | ||
2002 | goto out; | ||
2003 | |||
2004 | r = cache_create(ca, &cache); | ||
2005 | |||
2006 | r = copy_ctr_args(cache, argc - 3, (const char **)argv + 3); | ||
2007 | if (r) { | ||
2008 | destroy(cache); | ||
2009 | goto out; | ||
2010 | } | ||
2011 | |||
2012 | ti->private = cache; | ||
2013 | |||
2014 | out: | ||
2015 | destroy_cache_args(ca); | ||
2016 | return r; | ||
2017 | } | ||
2018 | |||
2019 | static unsigned cache_num_write_bios(struct dm_target *ti, struct bio *bio) | ||
2020 | { | ||
2021 | int r; | ||
2022 | struct cache *cache = ti->private; | ||
2023 | dm_oblock_t block = get_bio_block(cache, bio); | ||
2024 | dm_cblock_t cblock; | ||
2025 | |||
2026 | r = policy_lookup(cache->policy, block, &cblock); | ||
2027 | if (r < 0) | ||
2028 | return 2; /* assume the worst */ | ||
2029 | |||
2030 | return (!r && !is_dirty(cache, cblock)) ? 2 : 1; | ||
2031 | } | ||
2032 | |||
2033 | static int cache_map(struct dm_target *ti, struct bio *bio) | ||
2034 | { | ||
2035 | struct cache *cache = ti->private; | ||
2036 | |||
2037 | int r; | ||
2038 | dm_oblock_t block = get_bio_block(cache, bio); | ||
2039 | bool can_migrate = false; | ||
2040 | bool discarded_block; | ||
2041 | struct dm_bio_prison_cell *cell; | ||
2042 | struct policy_result lookup_result; | ||
2043 | struct per_bio_data *pb; | ||
2044 | |||
2045 | if (from_oblock(block) > from_oblock(cache->origin_blocks)) { | ||
2046 | /* | ||
2047 | * This can only occur if the io goes to a partial block at | ||
2048 | * the end of the origin device. We don't cache these. | ||
2049 | * Just remap to the origin and carry on. | ||
2050 | */ | ||
2051 | remap_to_origin_clear_discard(cache, bio, block); | ||
2052 | return DM_MAPIO_REMAPPED; | ||
2053 | } | ||
2054 | |||
2055 | pb = init_per_bio_data(bio); | ||
2056 | |||
2057 | if (bio->bi_rw & (REQ_FLUSH | REQ_FUA | REQ_DISCARD)) { | ||
2058 | defer_bio(cache, bio); | ||
2059 | return DM_MAPIO_SUBMITTED; | ||
2060 | } | ||
2061 | |||
2062 | /* | ||
2063 | * Check to see if that block is currently migrating. | ||
2064 | */ | ||
2065 | cell = alloc_prison_cell(cache); | ||
2066 | if (!cell) { | ||
2067 | defer_bio(cache, bio); | ||
2068 | return DM_MAPIO_SUBMITTED; | ||
2069 | } | ||
2070 | |||
2071 | r = bio_detain(cache, block, bio, cell, | ||
2072 | (cell_free_fn) free_prison_cell, | ||
2073 | cache, &cell); | ||
2074 | if (r) { | ||
2075 | if (r < 0) | ||
2076 | defer_bio(cache, bio); | ||
2077 | |||
2078 | return DM_MAPIO_SUBMITTED; | ||
2079 | } | ||
2080 | |||
2081 | discarded_block = is_discarded_oblock(cache, block); | ||
2082 | |||
2083 | r = policy_map(cache->policy, block, false, can_migrate, discarded_block, | ||
2084 | bio, &lookup_result); | ||
2085 | if (r == -EWOULDBLOCK) { | ||
2086 | cell_defer(cache, cell, true); | ||
2087 | return DM_MAPIO_SUBMITTED; | ||
2088 | |||
2089 | } else if (r) { | ||
2090 | DMERR_LIMIT("Unexpected return from cache replacement policy: %d", r); | ||
2091 | bio_io_error(bio); | ||
2092 | return DM_MAPIO_SUBMITTED; | ||
2093 | } | ||
2094 | |||
2095 | switch (lookup_result.op) { | ||
2096 | case POLICY_HIT: | ||
2097 | inc_hit_counter(cache, bio); | ||
2098 | pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); | ||
2099 | |||
2100 | if (is_writethrough_io(cache, bio, lookup_result.cblock)) { | ||
2101 | /* | ||
2102 | * No need to mark anything dirty in write through mode. | ||
2103 | */ | ||
2104 | pb->req_nr == 0 ? | ||
2105 | remap_to_cache(cache, bio, lookup_result.cblock) : | ||
2106 | remap_to_origin_clear_discard(cache, bio, block); | ||
2107 | cell_defer(cache, cell, false); | ||
2108 | } else { | ||
2109 | remap_to_cache_dirty(cache, bio, block, lookup_result.cblock); | ||
2110 | cell_defer(cache, cell, false); | ||
2111 | } | ||
2112 | break; | ||
2113 | |||
2114 | case POLICY_MISS: | ||
2115 | inc_miss_counter(cache, bio); | ||
2116 | pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); | ||
2117 | |||
2118 | if (pb->req_nr != 0) { | ||
2119 | /* | ||
2120 | * This is a duplicate writethrough io that is no | ||
2121 | * longer needed because the block has been demoted. | ||
2122 | */ | ||
2123 | bio_endio(bio, 0); | ||
2124 | cell_defer(cache, cell, false); | ||
2125 | return DM_MAPIO_SUBMITTED; | ||
2126 | } else { | ||
2127 | remap_to_origin_clear_discard(cache, bio, block); | ||
2128 | cell_defer(cache, cell, false); | ||
2129 | } | ||
2130 | break; | ||
2131 | |||
2132 | default: | ||
2133 | DMERR_LIMIT("%s: erroring bio: unknown policy op: %u", __func__, | ||
2134 | (unsigned) lookup_result.op); | ||
2135 | bio_io_error(bio); | ||
2136 | return DM_MAPIO_SUBMITTED; | ||
2137 | } | ||
2138 | |||
2139 | return DM_MAPIO_REMAPPED; | ||
2140 | } | ||
2141 | |||
2142 | static int cache_end_io(struct dm_target *ti, struct bio *bio, int error) | ||
2143 | { | ||
2144 | struct cache *cache = ti->private; | ||
2145 | unsigned long flags; | ||
2146 | struct per_bio_data *pb = get_per_bio_data(bio); | ||
2147 | |||
2148 | if (pb->tick) { | ||
2149 | policy_tick(cache->policy); | ||
2150 | |||
2151 | spin_lock_irqsave(&cache->lock, flags); | ||
2152 | cache->need_tick_bio = true; | ||
2153 | spin_unlock_irqrestore(&cache->lock, flags); | ||
2154 | } | ||
2155 | |||
2156 | check_for_quiesced_migrations(cache, pb); | ||
2157 | |||
2158 | return 0; | ||
2159 | } | ||
2160 | |||
2161 | static int write_dirty_bitset(struct cache *cache) | ||
2162 | { | ||
2163 | unsigned i, r; | ||
2164 | |||
2165 | for (i = 0; i < from_cblock(cache->cache_size); i++) { | ||
2166 | r = dm_cache_set_dirty(cache->cmd, to_cblock(i), | ||
2167 | is_dirty(cache, to_cblock(i))); | ||
2168 | if (r) | ||
2169 | return r; | ||
2170 | } | ||
2171 | |||
2172 | return 0; | ||
2173 | } | ||
2174 | |||
2175 | static int write_discard_bitset(struct cache *cache) | ||
2176 | { | ||
2177 | unsigned i, r; | ||
2178 | |||
2179 | r = dm_cache_discard_bitset_resize(cache->cmd, cache->discard_block_size, | ||
2180 | cache->discard_nr_blocks); | ||
2181 | if (r) { | ||
2182 | DMERR("could not resize on-disk discard bitset"); | ||
2183 | return r; | ||
2184 | } | ||
2185 | |||
2186 | for (i = 0; i < from_dblock(cache->discard_nr_blocks); i++) { | ||
2187 | r = dm_cache_set_discard(cache->cmd, to_dblock(i), | ||
2188 | is_discarded(cache, to_dblock(i))); | ||
2189 | if (r) | ||
2190 | return r; | ||
2191 | } | ||
2192 | |||
2193 | return 0; | ||
2194 | } | ||
2195 | |||
2196 | static int save_hint(void *context, dm_cblock_t cblock, dm_oblock_t oblock, | ||
2197 | uint32_t hint) | ||
2198 | { | ||
2199 | struct cache *cache = context; | ||
2200 | return dm_cache_save_hint(cache->cmd, cblock, hint); | ||
2201 | } | ||
2202 | |||
2203 | static int write_hints(struct cache *cache) | ||
2204 | { | ||
2205 | int r; | ||
2206 | |||
2207 | r = dm_cache_begin_hints(cache->cmd, cache->policy); | ||
2208 | if (r) { | ||
2209 | DMERR("dm_cache_begin_hints failed"); | ||
2210 | return r; | ||
2211 | } | ||
2212 | |||
2213 | r = policy_walk_mappings(cache->policy, save_hint, cache); | ||
2214 | if (r) | ||
2215 | DMERR("policy_walk_mappings failed"); | ||
2216 | |||
2217 | return r; | ||
2218 | } | ||
2219 | |||
2220 | /* | ||
2221 | * returns true on success | ||
2222 | */ | ||
2223 | static bool sync_metadata(struct cache *cache) | ||
2224 | { | ||
2225 | int r1, r2, r3, r4; | ||
2226 | |||
2227 | r1 = write_dirty_bitset(cache); | ||
2228 | if (r1) | ||
2229 | DMERR("could not write dirty bitset"); | ||
2230 | |||
2231 | r2 = write_discard_bitset(cache); | ||
2232 | if (r2) | ||
2233 | DMERR("could not write discard bitset"); | ||
2234 | |||
2235 | save_stats(cache); | ||
2236 | |||
2237 | r3 = write_hints(cache); | ||
2238 | if (r3) | ||
2239 | DMERR("could not write hints"); | ||
2240 | |||
2241 | /* | ||
2242 | * If writing the above metadata failed, we still commit, but don't | ||
2243 | * set the clean shutdown flag. This will effectively force every | ||
2244 | * dirty bit to be set on reload. | ||
2245 | */ | ||
2246 | r4 = dm_cache_commit(cache->cmd, !r1 && !r2 && !r3); | ||
2247 | if (r4) | ||
2248 | DMERR("could not write cache metadata. Data loss may occur."); | ||
2249 | |||
2250 | return !r1 && !r2 && !r3 && !r4; | ||
2251 | } | ||
2252 | |||
2253 | static void cache_postsuspend(struct dm_target *ti) | ||
2254 | { | ||
2255 | struct cache *cache = ti->private; | ||
2256 | |||
2257 | start_quiescing(cache); | ||
2258 | wait_for_migrations(cache); | ||
2259 | stop_worker(cache); | ||
2260 | requeue_deferred_io(cache); | ||
2261 | stop_quiescing(cache); | ||
2262 | |||
2263 | (void) sync_metadata(cache); | ||
2264 | } | ||
2265 | |||
2266 | static int load_mapping(void *context, dm_oblock_t oblock, dm_cblock_t cblock, | ||
2267 | bool dirty, uint32_t hint, bool hint_valid) | ||
2268 | { | ||
2269 | int r; | ||
2270 | struct cache *cache = context; | ||
2271 | |||
2272 | r = policy_load_mapping(cache->policy, oblock, cblock, hint, hint_valid); | ||
2273 | if (r) | ||
2274 | return r; | ||
2275 | |||
2276 | if (dirty) | ||
2277 | set_dirty(cache, oblock, cblock); | ||
2278 | else | ||
2279 | clear_dirty(cache, oblock, cblock); | ||
2280 | |||
2281 | return 0; | ||
2282 | } | ||
2283 | |||
2284 | static int load_discard(void *context, sector_t discard_block_size, | ||
2285 | dm_dblock_t dblock, bool discard) | ||
2286 | { | ||
2287 | struct cache *cache = context; | ||
2288 | |||
2289 | /* FIXME: handle mis-matched block size */ | ||
2290 | |||
2291 | if (discard) | ||
2292 | set_discard(cache, dblock); | ||
2293 | else | ||
2294 | clear_discard(cache, dblock); | ||
2295 | |||
2296 | return 0; | ||
2297 | } | ||
2298 | |||
2299 | static int cache_preresume(struct dm_target *ti) | ||
2300 | { | ||
2301 | int r = 0; | ||
2302 | struct cache *cache = ti->private; | ||
2303 | sector_t actual_cache_size = get_dev_size(cache->cache_dev); | ||
2304 | (void) sector_div(actual_cache_size, cache->sectors_per_block); | ||
2305 | |||
2306 | /* | ||
2307 | * Check to see if the cache has resized. | ||
2308 | */ | ||
2309 | if (from_cblock(cache->cache_size) != actual_cache_size || !cache->sized) { | ||
2310 | cache->cache_size = to_cblock(actual_cache_size); | ||
2311 | |||
2312 | r = dm_cache_resize(cache->cmd, cache->cache_size); | ||
2313 | if (r) { | ||
2314 | DMERR("could not resize cache metadata"); | ||
2315 | return r; | ||
2316 | } | ||
2317 | |||
2318 | cache->sized = true; | ||
2319 | } | ||
2320 | |||
2321 | if (!cache->loaded_mappings) { | ||
2322 | r = dm_cache_load_mappings(cache->cmd, | ||
2323 | dm_cache_policy_get_name(cache->policy), | ||
2324 | load_mapping, cache); | ||
2325 | if (r) { | ||
2326 | DMERR("could not load cache mappings"); | ||
2327 | return r; | ||
2328 | } | ||
2329 | |||
2330 | cache->loaded_mappings = true; | ||
2331 | } | ||
2332 | |||
2333 | if (!cache->loaded_discards) { | ||
2334 | r = dm_cache_load_discards(cache->cmd, load_discard, cache); | ||
2335 | if (r) { | ||
2336 | DMERR("could not load origin discards"); | ||
2337 | return r; | ||
2338 | } | ||
2339 | |||
2340 | cache->loaded_discards = true; | ||
2341 | } | ||
2342 | |||
2343 | return r; | ||
2344 | } | ||
2345 | |||
2346 | static void cache_resume(struct dm_target *ti) | ||
2347 | { | ||
2348 | struct cache *cache = ti->private; | ||
2349 | |||
2350 | cache->need_tick_bio = true; | ||
2351 | do_waker(&cache->waker.work); | ||
2352 | } | ||
2353 | |||
2354 | /* | ||
2355 | * Status format: | ||
2356 | * | ||
2357 | * <#used metadata blocks>/<#total metadata blocks> | ||
2358 | * <#read hits> <#read misses> <#write hits> <#write misses> | ||
2359 | * <#demotions> <#promotions> <#blocks in cache> <#dirty> | ||
2360 | * <#features> <features>* | ||
2361 | * <#core args> <core args> | ||
2362 | * <#policy args> <policy args>* | ||
2363 | */ | ||
2364 | static void cache_status(struct dm_target *ti, status_type_t type, | ||
2365 | unsigned status_flags, char *result, unsigned maxlen) | ||
2366 | { | ||
2367 | int r = 0; | ||
2368 | unsigned i; | ||
2369 | ssize_t sz = 0; | ||
2370 | dm_block_t nr_free_blocks_metadata = 0; | ||
2371 | dm_block_t nr_blocks_metadata = 0; | ||
2372 | char buf[BDEVNAME_SIZE]; | ||
2373 | struct cache *cache = ti->private; | ||
2374 | dm_cblock_t residency; | ||
2375 | |||
2376 | switch (type) { | ||
2377 | case STATUSTYPE_INFO: | ||
2378 | /* Commit to ensure statistics aren't out-of-date */ | ||
2379 | if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti)) { | ||
2380 | r = dm_cache_commit(cache->cmd, false); | ||
2381 | if (r) | ||
2382 | DMERR("could not commit metadata for accurate status"); | ||
2383 | } | ||
2384 | |||
2385 | r = dm_cache_get_free_metadata_block_count(cache->cmd, | ||
2386 | &nr_free_blocks_metadata); | ||
2387 | if (r) { | ||
2388 | DMERR("could not get metadata free block count"); | ||
2389 | goto err; | ||
2390 | } | ||
2391 | |||
2392 | r = dm_cache_get_metadata_dev_size(cache->cmd, &nr_blocks_metadata); | ||
2393 | if (r) { | ||
2394 | DMERR("could not get metadata device size"); | ||
2395 | goto err; | ||
2396 | } | ||
2397 | |||
2398 | residency = policy_residency(cache->policy); | ||
2399 | |||
2400 | DMEMIT("%llu/%llu %u %u %u %u %u %u %llu %u ", | ||
2401 | (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata), | ||
2402 | (unsigned long long)nr_blocks_metadata, | ||
2403 | (unsigned) atomic_read(&cache->stats.read_hit), | ||
2404 | (unsigned) atomic_read(&cache->stats.read_miss), | ||
2405 | (unsigned) atomic_read(&cache->stats.write_hit), | ||
2406 | (unsigned) atomic_read(&cache->stats.write_miss), | ||
2407 | (unsigned) atomic_read(&cache->stats.demotion), | ||
2408 | (unsigned) atomic_read(&cache->stats.promotion), | ||
2409 | (unsigned long long) from_cblock(residency), | ||
2410 | cache->nr_dirty); | ||
2411 | |||
2412 | if (cache->features.write_through) | ||
2413 | DMEMIT("1 writethrough "); | ||
2414 | else | ||
2415 | DMEMIT("0 "); | ||
2416 | |||
2417 | DMEMIT("2 migration_threshold %llu ", (unsigned long long) cache->migration_threshold); | ||
2418 | if (sz < maxlen) { | ||
2419 | r = policy_emit_config_values(cache->policy, result + sz, maxlen - sz); | ||
2420 | if (r) | ||
2421 | DMERR("policy_emit_config_values returned %d", r); | ||
2422 | } | ||
2423 | |||
2424 | break; | ||
2425 | |||
2426 | case STATUSTYPE_TABLE: | ||
2427 | format_dev_t(buf, cache->metadata_dev->bdev->bd_dev); | ||
2428 | DMEMIT("%s ", buf); | ||
2429 | format_dev_t(buf, cache->cache_dev->bdev->bd_dev); | ||
2430 | DMEMIT("%s ", buf); | ||
2431 | format_dev_t(buf, cache->origin_dev->bdev->bd_dev); | ||
2432 | DMEMIT("%s", buf); | ||
2433 | |||
2434 | for (i = 0; i < cache->nr_ctr_args - 1; i++) | ||
2435 | DMEMIT(" %s", cache->ctr_args[i]); | ||
2436 | if (cache->nr_ctr_args) | ||
2437 | DMEMIT(" %s", cache->ctr_args[cache->nr_ctr_args - 1]); | ||
2438 | } | ||
2439 | |||
2440 | return; | ||
2441 | |||
2442 | err: | ||
2443 | DMEMIT("Error"); | ||
2444 | } | ||
2445 | |||
2446 | #define NOT_CORE_OPTION 1 | ||
2447 | |||
2448 | static int process_config_option(struct cache *cache, char **argv) | ||
2449 | { | ||
2450 | unsigned long tmp; | ||
2451 | |||
2452 | if (!strcasecmp(argv[0], "migration_threshold")) { | ||
2453 | if (kstrtoul(argv[1], 10, &tmp)) | ||
2454 | return -EINVAL; | ||
2455 | |||
2456 | cache->migration_threshold = tmp; | ||
2457 | return 0; | ||
2458 | } | ||
2459 | |||
2460 | return NOT_CORE_OPTION; | ||
2461 | } | ||
2462 | |||
2463 | /* | ||
2464 | * Supports <key> <value>. | ||
2465 | * | ||
2466 | * The key migration_threshold is supported by the cache target core. | ||
2467 | */ | ||
2468 | static int cache_message(struct dm_target *ti, unsigned argc, char **argv) | ||
2469 | { | ||
2470 | int r; | ||
2471 | struct cache *cache = ti->private; | ||
2472 | |||
2473 | if (argc != 2) | ||
2474 | return -EINVAL; | ||
2475 | |||
2476 | r = process_config_option(cache, argv); | ||
2477 | if (r == NOT_CORE_OPTION) | ||
2478 | return policy_set_config_value(cache->policy, argv[0], argv[1]); | ||
2479 | |||
2480 | return r; | ||
2481 | } | ||
2482 | |||
2483 | static int cache_iterate_devices(struct dm_target *ti, | ||
2484 | iterate_devices_callout_fn fn, void *data) | ||
2485 | { | ||
2486 | int r = 0; | ||
2487 | struct cache *cache = ti->private; | ||
2488 | |||
2489 | r = fn(ti, cache->cache_dev, 0, get_dev_size(cache->cache_dev), data); | ||
2490 | if (!r) | ||
2491 | r = fn(ti, cache->origin_dev, 0, ti->len, data); | ||
2492 | |||
2493 | return r; | ||
2494 | } | ||
2495 | |||
2496 | /* | ||
2497 | * We assume I/O is going to the origin (which is the volume | ||
2498 | * more likely to have restrictions e.g. by being striped). | ||
2499 | * (Looking up the exact location of the data would be expensive | ||
2500 | * and could always be out of date by the time the bio is submitted.) | ||
2501 | */ | ||
2502 | static int cache_bvec_merge(struct dm_target *ti, | ||
2503 | struct bvec_merge_data *bvm, | ||
2504 | struct bio_vec *biovec, int max_size) | ||
2505 | { | ||
2506 | struct cache *cache = ti->private; | ||
2507 | struct request_queue *q = bdev_get_queue(cache->origin_dev->bdev); | ||
2508 | |||
2509 | if (!q->merge_bvec_fn) | ||
2510 | return max_size; | ||
2511 | |||
2512 | bvm->bi_bdev = cache->origin_dev->bdev; | ||
2513 | return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); | ||
2514 | } | ||
2515 | |||
2516 | static void set_discard_limits(struct cache *cache, struct queue_limits *limits) | ||
2517 | { | ||
2518 | /* | ||
2519 | * FIXME: these limits may be incompatible with the cache device | ||
2520 | */ | ||
2521 | limits->max_discard_sectors = cache->discard_block_size * 1024; | ||
2522 | limits->discard_granularity = cache->discard_block_size << SECTOR_SHIFT; | ||
2523 | } | ||
2524 | |||
2525 | static void cache_io_hints(struct dm_target *ti, struct queue_limits *limits) | ||
2526 | { | ||
2527 | struct cache *cache = ti->private; | ||
2528 | |||
2529 | blk_limits_io_min(limits, 0); | ||
2530 | blk_limits_io_opt(limits, cache->sectors_per_block << SECTOR_SHIFT); | ||
2531 | set_discard_limits(cache, limits); | ||
2532 | } | ||
2533 | |||
2534 | /*----------------------------------------------------------------*/ | ||
2535 | |||
2536 | static struct target_type cache_target = { | ||
2537 | .name = "cache", | ||
2538 | .version = {1, 0, 0}, | ||
2539 | .module = THIS_MODULE, | ||
2540 | .ctr = cache_ctr, | ||
2541 | .dtr = cache_dtr, | ||
2542 | .map = cache_map, | ||
2543 | .end_io = cache_end_io, | ||
2544 | .postsuspend = cache_postsuspend, | ||
2545 | .preresume = cache_preresume, | ||
2546 | .resume = cache_resume, | ||
2547 | .status = cache_status, | ||
2548 | .message = cache_message, | ||
2549 | .iterate_devices = cache_iterate_devices, | ||
2550 | .merge = cache_bvec_merge, | ||
2551 | .io_hints = cache_io_hints, | ||
2552 | }; | ||
2553 | |||
2554 | static int __init dm_cache_init(void) | ||
2555 | { | ||
2556 | int r; | ||
2557 | |||
2558 | r = dm_register_target(&cache_target); | ||
2559 | if (r) { | ||
2560 | DMERR("cache target registration failed: %d", r); | ||
2561 | return r; | ||
2562 | } | ||
2563 | |||
2564 | migration_cache = KMEM_CACHE(dm_cache_migration, 0); | ||
2565 | if (!migration_cache) { | ||
2566 | dm_unregister_target(&cache_target); | ||
2567 | return -ENOMEM; | ||
2568 | } | ||
2569 | |||
2570 | return 0; | ||
2571 | } | ||
2572 | |||
2573 | static void __exit dm_cache_exit(void) | ||
2574 | { | ||
2575 | dm_unregister_target(&cache_target); | ||
2576 | kmem_cache_destroy(migration_cache); | ||
2577 | } | ||
2578 | |||
2579 | module_init(dm_cache_init); | ||
2580 | module_exit(dm_cache_exit); | ||
2581 | |||
2582 | MODULE_DESCRIPTION(DM_NAME " cache target"); | ||
2583 | MODULE_AUTHOR("Joe Thornber <ejt@redhat.com>"); | ||
2584 | MODULE_LICENSE("GPL"); | ||
diff --git a/drivers/md/persistent-data/dm-block-manager.c b/drivers/md/persistent-data/dm-block-manager.c index 28c3ed072a79..81b513890e2b 100644 --- a/drivers/md/persistent-data/dm-block-manager.c +++ b/drivers/md/persistent-data/dm-block-manager.c | |||
@@ -613,6 +613,7 @@ int dm_bm_flush_and_unlock(struct dm_block_manager *bm, | |||
613 | 613 | ||
614 | return dm_bufio_write_dirty_buffers(bm->bufio); | 614 | return dm_bufio_write_dirty_buffers(bm->bufio); |
615 | } | 615 | } |
616 | EXPORT_SYMBOL_GPL(dm_bm_flush_and_unlock); | ||
616 | 617 | ||
617 | void dm_bm_set_read_only(struct dm_block_manager *bm) | 618 | void dm_bm_set_read_only(struct dm_block_manager *bm) |
618 | { | 619 | { |