aeff7852cf79bf731ab69370fffe9ce0f4c38537
[linux-2.6.git] / drivers / md / persistent-data / dm-space-map-disk.c
1 /*
2  * Copyright (C) 2011 Red Hat, Inc.
3  *
4  * This file is released under the GPL.
5  */
6
7 #include "dm-space-map-checker.h"
8 #include "dm-space-map-common.h"
9 #include "dm-space-map-disk.h"
10 #include "dm-space-map.h"
11 #include "dm-transaction-manager.h"
12
13 #include <linux/list.h>
14 #include <linux/slab.h>
15 #include <linux/module.h>
16 #include <linux/device-mapper.h>
17
18 #define DM_MSG_PREFIX "space map disk"
19
20 /*----------------------------------------------------------------*/
21
22 /*
23  * Space map interface.
24  */
25 struct sm_disk {
26         struct dm_space_map sm;
27
28         struct ll_disk ll;
29         struct ll_disk old_ll;
30
31         dm_block_t begin;
32         dm_block_t nr_allocated_this_transaction;
33 };
34
35 static void sm_disk_destroy(struct dm_space_map *sm)
36 {
37         struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
38
39         kfree(smd);
40 }
41
42 static int sm_disk_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
43 {
44         struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
45
46         return sm_ll_extend(&smd->ll, extra_blocks);
47 }
48
49 static int sm_disk_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
50 {
51         struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
52         *count = smd->old_ll.nr_blocks;
53
54         return 0;
55 }
56
57 static int sm_disk_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
58 {
59         struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
60         *count = (smd->old_ll.nr_blocks - smd->old_ll.nr_allocated) - smd->nr_allocated_this_transaction;
61
62         return 0;
63 }
64
65 static int sm_disk_get_count(struct dm_space_map *sm, dm_block_t b,
66                              uint32_t *result)
67 {
68         struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
69         return sm_ll_lookup(&smd->ll, b, result);
70 }
71
72 static int sm_disk_count_is_more_than_one(struct dm_space_map *sm, dm_block_t b,
73                                           int *result)
74 {
75         int r;
76         uint32_t count;
77
78         r = sm_disk_get_count(sm, b, &count);
79         if (r)
80                 return r;
81
82         return count > 1;
83 }
84
85 static int sm_disk_set_count(struct dm_space_map *sm, dm_block_t b,
86                              uint32_t count)
87 {
88         int r;
89         uint32_t old_count;
90         enum allocation_event ev;
91         struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
92
93         r = sm_ll_insert(&smd->ll, b, count, &ev);
94         if (!r) {
95                 switch (ev) {
96                 case SM_NONE:
97                         break;
98
99                 case SM_ALLOC:
100                         /*
101                          * This _must_ be free in the prior transaction
102                          * otherwise we've lost atomicity.
103                          */
104                         smd->nr_allocated_this_transaction++;
105                         break;
106
107                 case SM_FREE:
108                         /*
109                          * It's only free if it's also free in the last
110                          * transaction.
111                          */
112                         r = sm_ll_lookup(&smd->old_ll, b, &old_count);
113                         if (r)
114                                 return r;
115
116                         if (!old_count)
117                                 smd->nr_allocated_this_transaction--;
118                         break;
119                 }
120         }
121
122         return r;
123 }
124
125 static int sm_disk_inc_block(struct dm_space_map *sm, dm_block_t b)
126 {
127         int r;
128         enum allocation_event ev;
129         struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
130
131         r = sm_ll_inc(&smd->ll, b, &ev);
132         if (!r && (ev == SM_ALLOC))
133                 /*
134                  * This _must_ be free in the prior transaction
135                  * otherwise we've lost atomicity.
136                  */
137                 smd->nr_allocated_this_transaction++;
138
139         return r;
140 }
141
142 static int sm_disk_dec_block(struct dm_space_map *sm, dm_block_t b)
143 {
144         int r;
145         uint32_t old_count;
146         enum allocation_event ev;
147         struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
148
149         r = sm_ll_dec(&smd->ll, b, &ev);
150         if (!r && (ev == SM_FREE)) {
151                 /*
152                  * It's only free if it's also free in the last
153                  * transaction.
154                  */
155                 r = sm_ll_lookup(&smd->old_ll, b, &old_count);
156                 if (r)
157                         return r;
158
159                 if (!old_count)
160                         smd->nr_allocated_this_transaction--;
161         }
162
163         return r;
164 }
165
166 static int sm_disk_new_block(struct dm_space_map *sm, dm_block_t *b)
167 {
168         int r;
169         enum allocation_event ev;
170         struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
171
172         /* FIXME: we should loop round a couple of times */
173         r = sm_ll_find_free_block(&smd->old_ll, smd->begin, smd->old_ll.nr_blocks, b);
174         if (r)
175                 return r;
176
177         smd->begin = *b + 1;
178         r = sm_ll_inc(&smd->ll, *b, &ev);
179         if (!r) {
180                 BUG_ON(ev != SM_ALLOC);
181                 smd->nr_allocated_this_transaction++;
182         }
183
184         return r;
185 }
186
187 static int sm_disk_commit(struct dm_space_map *sm)
188 {
189         int r;
190         dm_block_t nr_free;
191         struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
192
193         r = sm_disk_get_nr_free(sm, &nr_free);
194         if (r)
195                 return r;
196
197         r = sm_ll_commit(&smd->ll);
198         if (r)
199                 return r;
200
201         memcpy(&smd->old_ll, &smd->ll, sizeof(smd->old_ll));
202         smd->begin = 0;
203         smd->nr_allocated_this_transaction = 0;
204
205         r = sm_disk_get_nr_free(sm, &nr_free);
206         if (r)
207                 return r;
208
209         return 0;
210 }
211
212 static int sm_disk_root_size(struct dm_space_map *sm, size_t *result)
213 {
214         *result = sizeof(struct disk_sm_root);
215
216         return 0;
217 }
218
219 static int sm_disk_copy_root(struct dm_space_map *sm, void *where_le, size_t max)
220 {
221         struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
222         struct disk_sm_root root_le;
223
224         root_le.nr_blocks = cpu_to_le64(smd->ll.nr_blocks);
225         root_le.nr_allocated = cpu_to_le64(smd->ll.nr_allocated);
226         root_le.bitmap_root = cpu_to_le64(smd->ll.bitmap_root);
227         root_le.ref_count_root = cpu_to_le64(smd->ll.ref_count_root);
228
229         if (max < sizeof(root_le))
230                 return -ENOSPC;
231
232         memcpy(where_le, &root_le, sizeof(root_le));
233
234         return 0;
235 }
236
237 /*----------------------------------------------------------------*/
238
239 static struct dm_space_map ops = {
240         .destroy = sm_disk_destroy,
241         .extend = sm_disk_extend,
242         .get_nr_blocks = sm_disk_get_nr_blocks,
243         .get_nr_free = sm_disk_get_nr_free,
244         .get_count = sm_disk_get_count,
245         .count_is_more_than_one = sm_disk_count_is_more_than_one,
246         .set_count = sm_disk_set_count,
247         .inc_block = sm_disk_inc_block,
248         .dec_block = sm_disk_dec_block,
249         .new_block = sm_disk_new_block,
250         .commit = sm_disk_commit,
251         .root_size = sm_disk_root_size,
252         .copy_root = sm_disk_copy_root
253 };
254
255 static struct dm_space_map *dm_sm_disk_create_real(
256         struct dm_transaction_manager *tm,
257         dm_block_t nr_blocks)
258 {
259         int r;
260         struct sm_disk *smd;
261
262         smd = kmalloc(sizeof(*smd), GFP_KERNEL);
263         if (!smd)
264                 return ERR_PTR(-ENOMEM);
265
266         smd->begin = 0;
267         smd->nr_allocated_this_transaction = 0;
268         memcpy(&smd->sm, &ops, sizeof(smd->sm));
269
270         r = sm_ll_new_disk(&smd->ll, tm);
271         if (r)
272                 goto bad;
273
274         r = sm_ll_extend(&smd->ll, nr_blocks);
275         if (r)
276                 goto bad;
277
278         r = sm_disk_commit(&smd->sm);
279         if (r)
280                 goto bad;
281
282         return &smd->sm;
283
284 bad:
285         kfree(smd);
286         return ERR_PTR(r);
287 }
288
289 struct dm_space_map *dm_sm_disk_create(struct dm_transaction_manager *tm,
290                                        dm_block_t nr_blocks)
291 {
292         struct dm_space_map *sm = dm_sm_disk_create_real(tm, nr_blocks);
293         return dm_sm_checker_create_fresh(sm);
294 }
295 EXPORT_SYMBOL_GPL(dm_sm_disk_create);
296
297 static struct dm_space_map *dm_sm_disk_open_real(
298         struct dm_transaction_manager *tm,
299         void *root_le, size_t len)
300 {
301         int r;
302         struct sm_disk *smd;
303
304         smd = kmalloc(sizeof(*smd), GFP_KERNEL);
305         if (!smd)
306                 return ERR_PTR(-ENOMEM);
307
308         smd->begin = 0;
309         smd->nr_allocated_this_transaction = 0;
310         memcpy(&smd->sm, &ops, sizeof(smd->sm));
311
312         r = sm_ll_open_disk(&smd->ll, tm, root_le, len);
313         if (r)
314                 goto bad;
315
316         r = sm_disk_commit(&smd->sm);
317         if (r)
318                 goto bad;
319
320         return &smd->sm;
321
322 bad:
323         kfree(smd);
324         return ERR_PTR(r);
325 }
326
327 struct dm_space_map *dm_sm_disk_open(struct dm_transaction_manager *tm,
328                                      void *root_le, size_t len)
329 {
330         return dm_sm_checker_create(
331                 dm_sm_disk_open_real(tm, root_le, len));
332 }
333 EXPORT_SYMBOL_GPL(dm_sm_disk_open);
334
335 /*----------------------------------------------------------------*/