Root/
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 | |
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 | |
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 | |
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 | |
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 | |
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 | |
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 | return count > 1; |
82 | } |
83 | |
84 | static int sm_disk_set_count(struct dm_space_map *sm, dm_block_t b, |
85 | uint32_t count) |
86 | { |
87 | int r; |
88 | uint32_t old_count; |
89 | enum allocation_event ev; |
90 | struct sm_disk *smd = container_of(sm, struct sm_disk, sm); |
91 | |
92 | r = sm_ll_insert(&smd->ll, b, count, &ev); |
93 | if (!r) { |
94 | switch (ev) { |
95 | case SM_NONE: |
96 | break; |
97 | |
98 | case SM_ALLOC: |
99 | /* |
100 | * This _must_ be free in the prior transaction |
101 | * otherwise we've lost atomicity. |
102 | */ |
103 | smd->nr_allocated_this_transaction++; |
104 | break; |
105 | |
106 | case SM_FREE: |
107 | /* |
108 | * It's only free if it's also free in the last |
109 | * transaction. |
110 | */ |
111 | r = sm_ll_lookup(&smd->old_ll, b, &old_count); |
112 | if (r) |
113 | return r; |
114 | |
115 | if (!old_count) |
116 | smd->nr_allocated_this_transaction--; |
117 | break; |
118 | } |
119 | } |
120 | |
121 | return r; |
122 | } |
123 | |
124 | static int sm_disk_inc_block(struct dm_space_map *sm, dm_block_t b) |
125 | { |
126 | int r; |
127 | enum allocation_event ev; |
128 | struct sm_disk *smd = container_of(sm, struct sm_disk, sm); |
129 | |
130 | r = sm_ll_inc(&smd->ll, b, &ev); |
131 | if (!r && (ev == SM_ALLOC)) |
132 | /* |
133 | * This _must_ be free in the prior transaction |
134 | * otherwise we've lost atomicity. |
135 | */ |
136 | smd->nr_allocated_this_transaction++; |
137 | |
138 | return r; |
139 | } |
140 | |
141 | static int sm_disk_dec_block(struct dm_space_map *sm, dm_block_t b) |
142 | { |
143 | int r; |
144 | uint32_t old_count; |
145 | enum allocation_event ev; |
146 | struct sm_disk *smd = container_of(sm, struct sm_disk, sm); |
147 | |
148 | r = sm_ll_dec(&smd->ll, b, &ev); |
149 | if (!r && (ev == SM_FREE)) { |
150 | /* |
151 | * It's only free if it's also free in the last |
152 | * transaction. |
153 | */ |
154 | r = sm_ll_lookup(&smd->old_ll, b, &old_count); |
155 | if (r) |
156 | return r; |
157 | |
158 | if (!old_count) |
159 | smd->nr_allocated_this_transaction--; |
160 | } |
161 | |
162 | return r; |
163 | } |
164 | |
165 | static int sm_disk_new_block(struct dm_space_map *sm, dm_block_t *b) |
166 | { |
167 | int r; |
168 | enum allocation_event ev; |
169 | struct sm_disk *smd = container_of(sm, struct sm_disk, sm); |
170 | |
171 | /* FIXME: we should loop round a couple of times */ |
172 | r = sm_ll_find_free_block(&smd->old_ll, smd->begin, smd->old_ll.nr_blocks, b); |
173 | if (r) |
174 | return r; |
175 | |
176 | smd->begin = *b + 1; |
177 | r = sm_ll_inc(&smd->ll, *b, &ev); |
178 | if (!r) { |
179 | BUG_ON(ev != SM_ALLOC); |
180 | smd->nr_allocated_this_transaction++; |
181 | } |
182 | |
183 | return r; |
184 | } |
185 | |
186 | static int sm_disk_commit(struct dm_space_map *sm) |
187 | { |
188 | int r; |
189 | dm_block_t nr_free; |
190 | struct sm_disk *smd = container_of(sm, struct sm_disk, sm); |
191 | |
192 | r = sm_disk_get_nr_free(sm, &nr_free); |
193 | if (r) |
194 | return r; |
195 | |
196 | r = sm_ll_commit(&smd->ll); |
197 | if (r) |
198 | return r; |
199 | |
200 | memcpy(&smd->old_ll, &smd->ll, sizeof(smd->old_ll)); |
201 | smd->begin = 0; |
202 | smd->nr_allocated_this_transaction = 0; |
203 | |
204 | r = sm_disk_get_nr_free(sm, &nr_free); |
205 | if (r) |
206 | return r; |
207 | |
208 | return 0; |
209 | } |
210 | |
211 | static int sm_disk_root_size(struct dm_space_map *sm, size_t *result) |
212 | { |
213 | *result = sizeof(struct disk_sm_root); |
214 | |
215 | return 0; |
216 | } |
217 | |
218 | static int sm_disk_copy_root(struct dm_space_map *sm, void *where_le, size_t max) |
219 | { |
220 | struct sm_disk *smd = container_of(sm, struct sm_disk, sm); |
221 | struct disk_sm_root root_le; |
222 | |
223 | root_le.nr_blocks = cpu_to_le64(smd->ll.nr_blocks); |
224 | root_le.nr_allocated = cpu_to_le64(smd->ll.nr_allocated); |
225 | root_le.bitmap_root = cpu_to_le64(smd->ll.bitmap_root); |
226 | root_le.ref_count_root = cpu_to_le64(smd->ll.ref_count_root); |
227 | |
228 | if (max < sizeof(root_le)) |
229 | return -ENOSPC; |
230 | |
231 | memcpy(where_le, &root_le, sizeof(root_le)); |
232 | |
233 | return 0; |
234 | } |
235 | |
236 | /*----------------------------------------------------------------*/ |
237 | |
238 | static struct dm_space_map ops = { |
239 | .destroy = sm_disk_destroy, |
240 | .extend = sm_disk_extend, |
241 | .get_nr_blocks = sm_disk_get_nr_blocks, |
242 | .get_nr_free = sm_disk_get_nr_free, |
243 | .get_count = sm_disk_get_count, |
244 | .count_is_more_than_one = sm_disk_count_is_more_than_one, |
245 | .set_count = sm_disk_set_count, |
246 | .inc_block = sm_disk_inc_block, |
247 | .dec_block = sm_disk_dec_block, |
248 | .new_block = sm_disk_new_block, |
249 | .commit = sm_disk_commit, |
250 | .root_size = sm_disk_root_size, |
251 | .copy_root = sm_disk_copy_root |
252 | }; |
253 | |
254 | struct dm_space_map *dm_sm_disk_create(struct dm_transaction_manager *tm, |
255 | dm_block_t nr_blocks) |
256 | { |
257 | int r; |
258 | struct sm_disk *smd; |
259 | |
260 | smd = kmalloc(sizeof(*smd), GFP_KERNEL); |
261 | if (!smd) |
262 | return ERR_PTR(-ENOMEM); |
263 | |
264 | smd->begin = 0; |
265 | smd->nr_allocated_this_transaction = 0; |
266 | memcpy(&smd->sm, &ops, sizeof(smd->sm)); |
267 | |
268 | r = sm_ll_new_disk(&smd->ll, tm); |
269 | if (r) |
270 | goto bad; |
271 | |
272 | r = sm_ll_extend(&smd->ll, nr_blocks); |
273 | if (r) |
274 | goto bad; |
275 | |
276 | r = sm_disk_commit(&smd->sm); |
277 | if (r) |
278 | goto bad; |
279 | |
280 | return &smd->sm; |
281 | |
282 | bad: |
283 | kfree(smd); |
284 | return ERR_PTR(r); |
285 | } |
286 | EXPORT_SYMBOL_GPL(dm_sm_disk_create); |
287 | |
288 | struct dm_space_map *dm_sm_disk_open(struct dm_transaction_manager *tm, |
289 | void *root_le, size_t len) |
290 | { |
291 | int r; |
292 | struct sm_disk *smd; |
293 | |
294 | smd = kmalloc(sizeof(*smd), GFP_KERNEL); |
295 | if (!smd) |
296 | return ERR_PTR(-ENOMEM); |
297 | |
298 | smd->begin = 0; |
299 | smd->nr_allocated_this_transaction = 0; |
300 | memcpy(&smd->sm, &ops, sizeof(smd->sm)); |
301 | |
302 | r = sm_ll_open_disk(&smd->ll, tm, root_le, len); |
303 | if (r) |
304 | goto bad; |
305 | |
306 | r = sm_disk_commit(&smd->sm); |
307 | if (r) |
308 | goto bad; |
309 | |
310 | return &smd->sm; |
311 | |
312 | bad: |
313 | kfree(smd); |
314 | return ERR_PTR(r); |
315 | } |
316 | EXPORT_SYMBOL_GPL(dm_sm_disk_open); |
317 | |
318 | /*----------------------------------------------------------------*/ |
319 |
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