1 /*
2 * Copyright (C) 2011 Red Hat, Inc.
3 *
4 * This file is released under the GPL.
5 */
6
7 #include "dm-space-map-common.h"
8 #include "dm-space-map-disk.h"
9 #include "dm-space-map.h"
10 #include "dm-transaction-manager.h"
11
12 #include <linux/list.h>
13 #include <linux/slab.h>
14 #include <linux/export.h>
15 #include <linux/device-mapper.h>
16
17 #define DM_MSG_PREFIX "space map disk"
18
19 /*----------------------------------------------------------------*/
20
21 /*
22 * Space map interface.
23 */
24 struct sm_disk {
25 struct dm_space_map sm;
26
27 struct ll_disk ll;
28 struct ll_disk old_ll;
29
30 dm_block_t begin;
31 dm_block_t nr_allocated_this_transaction;
32 };
33
sm_disk_destroy(struct dm_space_map * sm)34 static void sm_disk_destroy(struct dm_space_map *sm)
35 {
36 struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
37
38 kfree(smd);
39 }
40
sm_disk_extend(struct dm_space_map * sm,dm_block_t extra_blocks)41 static int sm_disk_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
42 {
43 struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
44
45 return sm_ll_extend(&smd->ll, extra_blocks);
46 }
47
sm_disk_get_nr_blocks(struct dm_space_map * sm,dm_block_t * count)48 static int sm_disk_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
49 {
50 struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
51 *count = smd->old_ll.nr_blocks;
52
53 return 0;
54 }
55
sm_disk_get_nr_free(struct dm_space_map * sm,dm_block_t * count)56 static int sm_disk_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
57 {
58 struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
59 *count = (smd->old_ll.nr_blocks - smd->old_ll.nr_allocated) - smd->nr_allocated_this_transaction;
60
61 return 0;
62 }
63
sm_disk_get_count(struct dm_space_map * sm,dm_block_t b,uint32_t * result)64 static int sm_disk_get_count(struct dm_space_map *sm, dm_block_t b,
65 uint32_t *result)
66 {
67 struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
68 return sm_ll_lookup(&smd->ll, b, result);
69 }
70
sm_disk_count_is_more_than_one(struct dm_space_map * sm,dm_block_t b,int * result)71 static int sm_disk_count_is_more_than_one(struct dm_space_map *sm, dm_block_t b,
72 int *result)
73 {
74 int r;
75 uint32_t count;
76
77 r = sm_disk_get_count(sm, b, &count);
78 if (r)
79 return r;
80
81 *result = count > 1;
82
83 return 0;
84 }
85
sm_disk_set_count(struct dm_space_map * sm,dm_block_t b,uint32_t count)86 static int sm_disk_set_count(struct dm_space_map *sm, dm_block_t b,
87 uint32_t count)
88 {
89 int r;
90 uint32_t old_count;
91 enum allocation_event ev;
92 struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
93
94 r = sm_ll_insert(&smd->ll, b, count, &ev);
95 if (!r) {
96 switch (ev) {
97 case SM_NONE:
98 break;
99
100 case SM_ALLOC:
101 /*
102 * This _must_ be free in the prior transaction
103 * otherwise we've lost atomicity.
104 */
105 smd->nr_allocated_this_transaction++;
106 break;
107
108 case SM_FREE:
109 /*
110 * It's only free if it's also free in the last
111 * transaction.
112 */
113 r = sm_ll_lookup(&smd->old_ll, b, &old_count);
114 if (r)
115 return r;
116
117 if (!old_count)
118 smd->nr_allocated_this_transaction--;
119 break;
120 }
121 }
122
123 return r;
124 }
125
sm_disk_inc_block(struct dm_space_map * sm,dm_block_t b)126 static int sm_disk_inc_block(struct dm_space_map *sm, dm_block_t b)
127 {
128 int r;
129 enum allocation_event ev;
130 struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
131
132 r = sm_ll_inc(&smd->ll, b, &ev);
133 if (!r && (ev == SM_ALLOC))
134 /*
135 * This _must_ be free in the prior transaction
136 * otherwise we've lost atomicity.
137 */
138 smd->nr_allocated_this_transaction++;
139
140 return r;
141 }
142
sm_disk_dec_block(struct dm_space_map * sm,dm_block_t b)143 static int sm_disk_dec_block(struct dm_space_map *sm, dm_block_t b)
144 {
145 int r;
146 uint32_t old_count;
147 enum allocation_event ev;
148 struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
149
150 r = sm_ll_dec(&smd->ll, b, &ev);
151 if (!r && (ev == SM_FREE)) {
152 /*
153 * It's only free if it's also free in the last
154 * transaction.
155 */
156 r = sm_ll_lookup(&smd->old_ll, b, &old_count);
157 if (!r && !old_count)
158 smd->nr_allocated_this_transaction--;
159 }
160
161 return r;
162 }
163
sm_disk_new_block(struct dm_space_map * sm,dm_block_t * b)164 static int sm_disk_new_block(struct dm_space_map *sm, dm_block_t *b)
165 {
166 int r;
167 enum allocation_event ev;
168 struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
169
170 /*
171 * Any block we allocate has to be free in both the old and current ll.
172 */
173 r = sm_ll_find_common_free_block(&smd->old_ll, &smd->ll, smd->begin, smd->ll.nr_blocks, b);
174 if (r == -ENOSPC) {
175 /*
176 * There's no free block between smd->begin and the end of the metadata device.
177 * We search before smd->begin in case something has been freed.
178 */
179 r = sm_ll_find_common_free_block(&smd->old_ll, &smd->ll, 0, smd->begin, b);
180 }
181
182 if (r)
183 return r;
184
185 smd->begin = *b + 1;
186 r = sm_ll_inc(&smd->ll, *b, &ev);
187 if (!r) {
188 BUG_ON(ev != SM_ALLOC);
189 smd->nr_allocated_this_transaction++;
190 }
191
192 return r;
193 }
194
sm_disk_commit(struct dm_space_map * sm)195 static int sm_disk_commit(struct dm_space_map *sm)
196 {
197 int r;
198 dm_block_t nr_free;
199 struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
200
201 r = sm_disk_get_nr_free(sm, &nr_free);
202 if (r)
203 return r;
204
205 r = sm_ll_commit(&smd->ll);
206 if (r)
207 return r;
208
209 memcpy(&smd->old_ll, &smd->ll, sizeof(smd->old_ll));
210 smd->nr_allocated_this_transaction = 0;
211
212 r = sm_disk_get_nr_free(sm, &nr_free);
213 if (r)
214 return r;
215
216 return 0;
217 }
218
sm_disk_root_size(struct dm_space_map * sm,size_t * result)219 static int sm_disk_root_size(struct dm_space_map *sm, size_t *result)
220 {
221 *result = sizeof(struct disk_sm_root);
222
223 return 0;
224 }
225
sm_disk_copy_root(struct dm_space_map * sm,void * where_le,size_t max)226 static int sm_disk_copy_root(struct dm_space_map *sm, void *where_le, size_t max)
227 {
228 struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
229 struct disk_sm_root root_le;
230
231 root_le.nr_blocks = cpu_to_le64(smd->ll.nr_blocks);
232 root_le.nr_allocated = cpu_to_le64(smd->ll.nr_allocated);
233 root_le.bitmap_root = cpu_to_le64(smd->ll.bitmap_root);
234 root_le.ref_count_root = cpu_to_le64(smd->ll.ref_count_root);
235
236 if (max < sizeof(root_le))
237 return -ENOSPC;
238
239 memcpy(where_le, &root_le, sizeof(root_le));
240
241 return 0;
242 }
243
244 /*----------------------------------------------------------------*/
245
246 static struct dm_space_map ops = {
247 .destroy = sm_disk_destroy,
248 .extend = sm_disk_extend,
249 .get_nr_blocks = sm_disk_get_nr_blocks,
250 .get_nr_free = sm_disk_get_nr_free,
251 .get_count = sm_disk_get_count,
252 .count_is_more_than_one = sm_disk_count_is_more_than_one,
253 .set_count = sm_disk_set_count,
254 .inc_block = sm_disk_inc_block,
255 .dec_block = sm_disk_dec_block,
256 .new_block = sm_disk_new_block,
257 .commit = sm_disk_commit,
258 .root_size = sm_disk_root_size,
259 .copy_root = sm_disk_copy_root,
260 .register_threshold_callback = NULL
261 };
262
dm_sm_disk_create(struct dm_transaction_manager * tm,dm_block_t nr_blocks)263 struct dm_space_map *dm_sm_disk_create(struct dm_transaction_manager *tm,
264 dm_block_t nr_blocks)
265 {
266 int r;
267 struct sm_disk *smd;
268
269 smd = kmalloc(sizeof(*smd), GFP_KERNEL);
270 if (!smd)
271 return ERR_PTR(-ENOMEM);
272
273 smd->begin = 0;
274 smd->nr_allocated_this_transaction = 0;
275 memcpy(&smd->sm, &ops, sizeof(smd->sm));
276
277 r = sm_ll_new_disk(&smd->ll, tm);
278 if (r)
279 goto bad;
280
281 r = sm_ll_extend(&smd->ll, nr_blocks);
282 if (r)
283 goto bad;
284
285 r = sm_disk_commit(&smd->sm);
286 if (r)
287 goto bad;
288
289 return &smd->sm;
290
291 bad:
292 kfree(smd);
293 return ERR_PTR(r);
294 }
295 EXPORT_SYMBOL_GPL(dm_sm_disk_create);
296
dm_sm_disk_open(struct dm_transaction_manager * tm,void * root_le,size_t len)297 struct dm_space_map *dm_sm_disk_open(struct dm_transaction_manager *tm,
298 void *root_le, size_t len)
299 {
300 int r;
301 struct sm_disk *smd;
302
303 smd = kmalloc(sizeof(*smd), GFP_KERNEL);
304 if (!smd)
305 return ERR_PTR(-ENOMEM);
306
307 smd->begin = 0;
308 smd->nr_allocated_this_transaction = 0;
309 memcpy(&smd->sm, &ops, sizeof(smd->sm));
310
311 r = sm_ll_open_disk(&smd->ll, tm, root_le, len);
312 if (r)
313 goto bad;
314
315 r = sm_disk_commit(&smd->sm);
316 if (r)
317 goto bad;
318
319 return &smd->sm;
320
321 bad:
322 kfree(smd);
323 return ERR_PTR(r);
324 }
325 EXPORT_SYMBOL_GPL(dm_sm_disk_open);
326
327 /*----------------------------------------------------------------*/
328