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f7d0fe02 KW |
1 | /* |
2 | * Block driver for the QCOW version 2 format | |
3 | * | |
4 | * Copyright (c) 2004-2006 Fabrice Bellard | |
5 | * | |
6 | * Permission is hereby granted, free of charge, to any person obtaining a copy | |
7 | * of this software and associated documentation files (the "Software"), to deal | |
8 | * in the Software without restriction, including without limitation the rights | |
9 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
10 | * copies of the Software, and to permit persons to whom the Software is | |
11 | * furnished to do so, subject to the following conditions: | |
12 | * | |
13 | * The above copyright notice and this permission notice shall be included in | |
14 | * all copies or substantial portions of the Software. | |
15 | * | |
16 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
17 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
18 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL | |
19 | * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
20 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
21 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN | |
22 | * THE SOFTWARE. | |
23 | */ | |
24 | ||
25 | #include "qemu-common.h" | |
737e150e | 26 | #include "block/block_int.h" |
f7d0fe02 | 27 | #include "block/qcow2.h" |
a40f1c2a HR |
28 | #include "qemu/range.h" |
29 | #include "qapi/qmp/types.h" | |
c120f0fa | 30 | #include "qapi-event.h" |
f7d0fe02 | 31 | |
bb572aef | 32 | static int64_t alloc_clusters_noref(BlockDriverState *bs, uint64_t size); |
92dcb59f | 33 | static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs, |
f7d0fe02 | 34 | int64_t offset, int64_t length, |
6cfcb9b8 | 35 | int addend, enum qcow2_discard_type type); |
f7d0fe02 | 36 | |
3b88e52b | 37 | |
f7d0fe02 KW |
38 | /*********************************************************/ |
39 | /* refcount handling */ | |
40 | ||
ed6ccf0f | 41 | int qcow2_refcount_init(BlockDriverState *bs) |
f7d0fe02 KW |
42 | { |
43 | BDRVQcowState *s = bs->opaque; | |
5dab2fad KW |
44 | unsigned int refcount_table_size2, i; |
45 | int ret; | |
f7d0fe02 | 46 | |
5dab2fad | 47 | assert(s->refcount_table_size <= INT_MAX / sizeof(uint64_t)); |
f7d0fe02 | 48 | refcount_table_size2 = s->refcount_table_size * sizeof(uint64_t); |
7267c094 | 49 | s->refcount_table = g_malloc(refcount_table_size2); |
f7d0fe02 | 50 | if (s->refcount_table_size > 0) { |
66f82cee KW |
51 | BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_LOAD); |
52 | ret = bdrv_pread(bs->file, s->refcount_table_offset, | |
f7d0fe02 KW |
53 | s->refcount_table, refcount_table_size2); |
54 | if (ret != refcount_table_size2) | |
55 | goto fail; | |
56 | for(i = 0; i < s->refcount_table_size; i++) | |
57 | be64_to_cpus(&s->refcount_table[i]); | |
58 | } | |
59 | return 0; | |
60 | fail: | |
61 | return -ENOMEM; | |
62 | } | |
63 | ||
ed6ccf0f | 64 | void qcow2_refcount_close(BlockDriverState *bs) |
f7d0fe02 KW |
65 | { |
66 | BDRVQcowState *s = bs->opaque; | |
7267c094 | 67 | g_free(s->refcount_table); |
f7d0fe02 KW |
68 | } |
69 | ||
70 | ||
71 | static int load_refcount_block(BlockDriverState *bs, | |
29c1a730 KW |
72 | int64_t refcount_block_offset, |
73 | void **refcount_block) | |
f7d0fe02 KW |
74 | { |
75 | BDRVQcowState *s = bs->opaque; | |
76 | int ret; | |
3b88e52b | 77 | |
66f82cee | 78 | BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_LOAD); |
29c1a730 KW |
79 | ret = qcow2_cache_get(bs, s->refcount_block_cache, refcount_block_offset, |
80 | refcount_block); | |
e14e8ba5 | 81 | |
29c1a730 | 82 | return ret; |
f7d0fe02 KW |
83 | } |
84 | ||
018faafd KW |
85 | /* |
86 | * Returns the refcount of the cluster given by its index. Any non-negative | |
87 | * return value is the refcount of the cluster, negative values are -errno | |
88 | * and indicate an error. | |
89 | */ | |
f7d0fe02 KW |
90 | static int get_refcount(BlockDriverState *bs, int64_t cluster_index) |
91 | { | |
92 | BDRVQcowState *s = bs->opaque; | |
db8a31d1 | 93 | uint64_t refcount_table_index, block_index; |
f7d0fe02 | 94 | int64_t refcount_block_offset; |
018faafd | 95 | int ret; |
29c1a730 KW |
96 | uint16_t *refcount_block; |
97 | uint16_t refcount; | |
f7d0fe02 KW |
98 | |
99 | refcount_table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT); | |
100 | if (refcount_table_index >= s->refcount_table_size) | |
101 | return 0; | |
26d49c46 HR |
102 | refcount_block_offset = |
103 | s->refcount_table[refcount_table_index] & REFT_OFFSET_MASK; | |
f7d0fe02 KW |
104 | if (!refcount_block_offset) |
105 | return 0; | |
29c1a730 KW |
106 | |
107 | ret = qcow2_cache_get(bs, s->refcount_block_cache, refcount_block_offset, | |
108 | (void**) &refcount_block); | |
109 | if (ret < 0) { | |
110 | return ret; | |
f7d0fe02 | 111 | } |
29c1a730 | 112 | |
f7d0fe02 KW |
113 | block_index = cluster_index & |
114 | ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1); | |
29c1a730 KW |
115 | refcount = be16_to_cpu(refcount_block[block_index]); |
116 | ||
117 | ret = qcow2_cache_put(bs, s->refcount_block_cache, | |
118 | (void**) &refcount_block); | |
119 | if (ret < 0) { | |
120 | return ret; | |
121 | } | |
122 | ||
123 | return refcount; | |
f7d0fe02 KW |
124 | } |
125 | ||
05121aed KW |
126 | /* |
127 | * Rounds the refcount table size up to avoid growing the table for each single | |
128 | * refcount block that is allocated. | |
129 | */ | |
130 | static unsigned int next_refcount_table_size(BDRVQcowState *s, | |
131 | unsigned int min_size) | |
132 | { | |
133 | unsigned int min_clusters = (min_size >> (s->cluster_bits - 3)) + 1; | |
134 | unsigned int refcount_table_clusters = | |
135 | MAX(1, s->refcount_table_size >> (s->cluster_bits - 3)); | |
136 | ||
137 | while (min_clusters > refcount_table_clusters) { | |
138 | refcount_table_clusters = (refcount_table_clusters * 3 + 1) / 2; | |
139 | } | |
140 | ||
141 | return refcount_table_clusters << (s->cluster_bits - 3); | |
142 | } | |
143 | ||
92dcb59f KW |
144 | |
145 | /* Checks if two offsets are described by the same refcount block */ | |
146 | static int in_same_refcount_block(BDRVQcowState *s, uint64_t offset_a, | |
147 | uint64_t offset_b) | |
148 | { | |
149 | uint64_t block_a = offset_a >> (2 * s->cluster_bits - REFCOUNT_SHIFT); | |
150 | uint64_t block_b = offset_b >> (2 * s->cluster_bits - REFCOUNT_SHIFT); | |
151 | ||
152 | return (block_a == block_b); | |
153 | } | |
154 | ||
155 | /* | |
156 | * Loads a refcount block. If it doesn't exist yet, it is allocated first | |
157 | * (including growing the refcount table if needed). | |
158 | * | |
29c1a730 | 159 | * Returns 0 on success or -errno in error case |
92dcb59f | 160 | */ |
29c1a730 KW |
161 | static int alloc_refcount_block(BlockDriverState *bs, |
162 | int64_t cluster_index, uint16_t **refcount_block) | |
f7d0fe02 KW |
163 | { |
164 | BDRVQcowState *s = bs->opaque; | |
92dcb59f KW |
165 | unsigned int refcount_table_index; |
166 | int ret; | |
167 | ||
66f82cee | 168 | BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC); |
8252278a | 169 | |
92dcb59f KW |
170 | /* Find the refcount block for the given cluster */ |
171 | refcount_table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT); | |
172 | ||
173 | if (refcount_table_index < s->refcount_table_size) { | |
174 | ||
175 | uint64_t refcount_block_offset = | |
76dc9e0c | 176 | s->refcount_table[refcount_table_index] & REFT_OFFSET_MASK; |
92dcb59f KW |
177 | |
178 | /* If it's already there, we're done */ | |
179 | if (refcount_block_offset) { | |
29c1a730 KW |
180 | return load_refcount_block(bs, refcount_block_offset, |
181 | (void**) refcount_block); | |
92dcb59f KW |
182 | } |
183 | } | |
184 | ||
185 | /* | |
186 | * If we came here, we need to allocate something. Something is at least | |
187 | * a cluster for the new refcount block. It may also include a new refcount | |
188 | * table if the old refcount table is too small. | |
189 | * | |
190 | * Note that allocating clusters here needs some special care: | |
191 | * | |
192 | * - We can't use the normal qcow2_alloc_clusters(), it would try to | |
193 | * increase the refcount and very likely we would end up with an endless | |
194 | * recursion. Instead we must place the refcount blocks in a way that | |
195 | * they can describe them themselves. | |
196 | * | |
197 | * - We need to consider that at this point we are inside update_refcounts | |
b106ad91 KW |
198 | * and potentially doing an initial refcount increase. This means that |
199 | * some clusters have already been allocated by the caller, but their | |
200 | * refcount isn't accurate yet. If we allocate clusters for metadata, we | |
201 | * need to return -EAGAIN to signal the caller that it needs to restart | |
202 | * the search for free clusters. | |
92dcb59f KW |
203 | * |
204 | * - alloc_clusters_noref and qcow2_free_clusters may load a different | |
205 | * refcount block into the cache | |
206 | */ | |
207 | ||
29c1a730 KW |
208 | *refcount_block = NULL; |
209 | ||
210 | /* We write to the refcount table, so we might depend on L2 tables */ | |
9991923b SH |
211 | ret = qcow2_cache_flush(bs, s->l2_table_cache); |
212 | if (ret < 0) { | |
213 | return ret; | |
214 | } | |
92dcb59f KW |
215 | |
216 | /* Allocate the refcount block itself and mark it as used */ | |
2eaa8f63 KW |
217 | int64_t new_block = alloc_clusters_noref(bs, s->cluster_size); |
218 | if (new_block < 0) { | |
219 | return new_block; | |
220 | } | |
f7d0fe02 | 221 | |
f7d0fe02 | 222 | #ifdef DEBUG_ALLOC2 |
92dcb59f KW |
223 | fprintf(stderr, "qcow2: Allocate refcount block %d for %" PRIx64 |
224 | " at %" PRIx64 "\n", | |
225 | refcount_table_index, cluster_index << s->cluster_bits, new_block); | |
f7d0fe02 | 226 | #endif |
92dcb59f KW |
227 | |
228 | if (in_same_refcount_block(s, new_block, cluster_index << s->cluster_bits)) { | |
25408c09 | 229 | /* Zero the new refcount block before updating it */ |
29c1a730 KW |
230 | ret = qcow2_cache_get_empty(bs, s->refcount_block_cache, new_block, |
231 | (void**) refcount_block); | |
232 | if (ret < 0) { | |
233 | goto fail_block; | |
234 | } | |
235 | ||
236 | memset(*refcount_block, 0, s->cluster_size); | |
25408c09 | 237 | |
92dcb59f KW |
238 | /* The block describes itself, need to update the cache */ |
239 | int block_index = (new_block >> s->cluster_bits) & | |
240 | ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1); | |
29c1a730 | 241 | (*refcount_block)[block_index] = cpu_to_be16(1); |
92dcb59f KW |
242 | } else { |
243 | /* Described somewhere else. This can recurse at most twice before we | |
244 | * arrive at a block that describes itself. */ | |
6cfcb9b8 KW |
245 | ret = update_refcount(bs, new_block, s->cluster_size, 1, |
246 | QCOW2_DISCARD_NEVER); | |
92dcb59f KW |
247 | if (ret < 0) { |
248 | goto fail_block; | |
249 | } | |
25408c09 | 250 | |
9991923b SH |
251 | ret = qcow2_cache_flush(bs, s->refcount_block_cache); |
252 | if (ret < 0) { | |
253 | goto fail_block; | |
254 | } | |
1c4c2814 | 255 | |
25408c09 KW |
256 | /* Initialize the new refcount block only after updating its refcount, |
257 | * update_refcount uses the refcount cache itself */ | |
29c1a730 KW |
258 | ret = qcow2_cache_get_empty(bs, s->refcount_block_cache, new_block, |
259 | (void**) refcount_block); | |
260 | if (ret < 0) { | |
261 | goto fail_block; | |
262 | } | |
263 | ||
264 | memset(*refcount_block, 0, s->cluster_size); | |
92dcb59f KW |
265 | } |
266 | ||
267 | /* Now the new refcount block needs to be written to disk */ | |
66f82cee | 268 | BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE); |
29c1a730 KW |
269 | qcow2_cache_entry_mark_dirty(s->refcount_block_cache, *refcount_block); |
270 | ret = qcow2_cache_flush(bs, s->refcount_block_cache); | |
92dcb59f KW |
271 | if (ret < 0) { |
272 | goto fail_block; | |
273 | } | |
274 | ||
275 | /* If the refcount table is big enough, just hook the block up there */ | |
276 | if (refcount_table_index < s->refcount_table_size) { | |
277 | uint64_t data64 = cpu_to_be64(new_block); | |
66f82cee | 278 | BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_HOOKUP); |
8b3b7206 | 279 | ret = bdrv_pwrite_sync(bs->file, |
92dcb59f KW |
280 | s->refcount_table_offset + refcount_table_index * sizeof(uint64_t), |
281 | &data64, sizeof(data64)); | |
282 | if (ret < 0) { | |
283 | goto fail_block; | |
284 | } | |
285 | ||
286 | s->refcount_table[refcount_table_index] = new_block; | |
b106ad91 KW |
287 | |
288 | /* The new refcount block may be where the caller intended to put its | |
289 | * data, so let it restart the search. */ | |
290 | return -EAGAIN; | |
29c1a730 KW |
291 | } |
292 | ||
293 | ret = qcow2_cache_put(bs, s->refcount_block_cache, (void**) refcount_block); | |
294 | if (ret < 0) { | |
295 | goto fail_block; | |
92dcb59f KW |
296 | } |
297 | ||
298 | /* | |
299 | * If we come here, we need to grow the refcount table. Again, a new | |
300 | * refcount table needs some space and we can't simply allocate to avoid | |
301 | * endless recursion. | |
302 | * | |
303 | * Therefore let's grab new refcount blocks at the end of the image, which | |
304 | * will describe themselves and the new refcount table. This way we can | |
305 | * reference them only in the new table and do the switch to the new | |
306 | * refcount table at once without producing an inconsistent state in | |
307 | * between. | |
308 | */ | |
66f82cee | 309 | BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_GROW); |
8252278a | 310 | |
92dcb59f KW |
311 | /* Calculate the number of refcount blocks needed so far */ |
312 | uint64_t refcount_block_clusters = 1 << (s->cluster_bits - REFCOUNT_SHIFT); | |
b106ad91 | 313 | uint64_t blocks_used = DIV_ROUND_UP(cluster_index, refcount_block_clusters); |
92dcb59f | 314 | |
2b5d5953 KW |
315 | if (blocks_used > QCOW_MAX_REFTABLE_SIZE / sizeof(uint64_t)) { |
316 | return -EFBIG; | |
317 | } | |
318 | ||
92dcb59f KW |
319 | /* And now we need at least one block more for the new metadata */ |
320 | uint64_t table_size = next_refcount_table_size(s, blocks_used + 1); | |
321 | uint64_t last_table_size; | |
322 | uint64_t blocks_clusters; | |
323 | do { | |
a3548077 KW |
324 | uint64_t table_clusters = |
325 | size_to_clusters(s, table_size * sizeof(uint64_t)); | |
92dcb59f KW |
326 | blocks_clusters = 1 + |
327 | ((table_clusters + refcount_block_clusters - 1) | |
328 | / refcount_block_clusters); | |
329 | uint64_t meta_clusters = table_clusters + blocks_clusters; | |
330 | ||
331 | last_table_size = table_size; | |
332 | table_size = next_refcount_table_size(s, blocks_used + | |
333 | ((meta_clusters + refcount_block_clusters - 1) | |
334 | / refcount_block_clusters)); | |
335 | ||
336 | } while (last_table_size != table_size); | |
337 | ||
338 | #ifdef DEBUG_ALLOC2 | |
339 | fprintf(stderr, "qcow2: Grow refcount table %" PRId32 " => %" PRId64 "\n", | |
340 | s->refcount_table_size, table_size); | |
341 | #endif | |
342 | ||
343 | /* Create the new refcount table and blocks */ | |
344 | uint64_t meta_offset = (blocks_used * refcount_block_clusters) * | |
345 | s->cluster_size; | |
346 | uint64_t table_offset = meta_offset + blocks_clusters * s->cluster_size; | |
7267c094 AL |
347 | uint16_t *new_blocks = g_malloc0(blocks_clusters * s->cluster_size); |
348 | uint64_t *new_table = g_malloc0(table_size * sizeof(uint64_t)); | |
92dcb59f | 349 | |
92dcb59f | 350 | /* Fill the new refcount table */ |
f7d0fe02 | 351 | memcpy(new_table, s->refcount_table, |
92dcb59f KW |
352 | s->refcount_table_size * sizeof(uint64_t)); |
353 | new_table[refcount_table_index] = new_block; | |
354 | ||
355 | int i; | |
356 | for (i = 0; i < blocks_clusters; i++) { | |
357 | new_table[blocks_used + i] = meta_offset + (i * s->cluster_size); | |
358 | } | |
359 | ||
360 | /* Fill the refcount blocks */ | |
361 | uint64_t table_clusters = size_to_clusters(s, table_size * sizeof(uint64_t)); | |
362 | int block = 0; | |
363 | for (i = 0; i < table_clusters + blocks_clusters; i++) { | |
364 | new_blocks[block++] = cpu_to_be16(1); | |
365 | } | |
366 | ||
367 | /* Write refcount blocks to disk */ | |
66f82cee | 368 | BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE_BLOCKS); |
8b3b7206 | 369 | ret = bdrv_pwrite_sync(bs->file, meta_offset, new_blocks, |
92dcb59f | 370 | blocks_clusters * s->cluster_size); |
7267c094 | 371 | g_free(new_blocks); |
92dcb59f KW |
372 | if (ret < 0) { |
373 | goto fail_table; | |
374 | } | |
375 | ||
376 | /* Write refcount table to disk */ | |
377 | for(i = 0; i < table_size; i++) { | |
378 | cpu_to_be64s(&new_table[i]); | |
379 | } | |
380 | ||
66f82cee | 381 | BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE_TABLE); |
8b3b7206 | 382 | ret = bdrv_pwrite_sync(bs->file, table_offset, new_table, |
92dcb59f KW |
383 | table_size * sizeof(uint64_t)); |
384 | if (ret < 0) { | |
385 | goto fail_table; | |
386 | } | |
387 | ||
388 | for(i = 0; i < table_size; i++) { | |
87267753 | 389 | be64_to_cpus(&new_table[i]); |
92dcb59f | 390 | } |
f7d0fe02 | 391 | |
92dcb59f KW |
392 | /* Hook up the new refcount table in the qcow2 header */ |
393 | uint8_t data[12]; | |
f7d0fe02 | 394 | cpu_to_be64w((uint64_t*)data, table_offset); |
92dcb59f | 395 | cpu_to_be32w((uint32_t*)(data + 8), table_clusters); |
66f82cee | 396 | BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_SWITCH_TABLE); |
8b3b7206 | 397 | ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, refcount_table_offset), |
92dcb59f KW |
398 | data, sizeof(data)); |
399 | if (ret < 0) { | |
400 | goto fail_table; | |
f2b7c8b3 KW |
401 | } |
402 | ||
92dcb59f KW |
403 | /* And switch it in memory */ |
404 | uint64_t old_table_offset = s->refcount_table_offset; | |
405 | uint64_t old_table_size = s->refcount_table_size; | |
406 | ||
7267c094 | 407 | g_free(s->refcount_table); |
f7d0fe02 | 408 | s->refcount_table = new_table; |
92dcb59f | 409 | s->refcount_table_size = table_size; |
f7d0fe02 KW |
410 | s->refcount_table_offset = table_offset; |
411 | ||
b106ad91 | 412 | /* Free old table. */ |
6cfcb9b8 KW |
413 | qcow2_free_clusters(bs, old_table_offset, old_table_size * sizeof(uint64_t), |
414 | QCOW2_DISCARD_OTHER); | |
f7d0fe02 | 415 | |
29c1a730 | 416 | ret = load_refcount_block(bs, new_block, (void**) refcount_block); |
92dcb59f | 417 | if (ret < 0) { |
29c1a730 | 418 | return ret; |
f7d0fe02 KW |
419 | } |
420 | ||
b106ad91 KW |
421 | /* If we were trying to do the initial refcount update for some cluster |
422 | * allocation, we might have used the same clusters to store newly | |
423 | * allocated metadata. Make the caller search some new space. */ | |
424 | return -EAGAIN; | |
f7d0fe02 | 425 | |
92dcb59f | 426 | fail_table: |
7267c094 | 427 | g_free(new_table); |
92dcb59f | 428 | fail_block: |
29c1a730 KW |
429 | if (*refcount_block != NULL) { |
430 | qcow2_cache_put(bs, s->refcount_block_cache, (void**) refcount_block); | |
3b88e52b | 431 | } |
29c1a730 | 432 | return ret; |
9923e05e KW |
433 | } |
434 | ||
0b919fae KW |
435 | void qcow2_process_discards(BlockDriverState *bs, int ret) |
436 | { | |
437 | BDRVQcowState *s = bs->opaque; | |
438 | Qcow2DiscardRegion *d, *next; | |
439 | ||
440 | QTAILQ_FOREACH_SAFE(d, &s->discards, next, next) { | |
441 | QTAILQ_REMOVE(&s->discards, d, next); | |
442 | ||
443 | /* Discard is optional, ignore the return value */ | |
444 | if (ret >= 0) { | |
445 | bdrv_discard(bs->file, | |
446 | d->offset >> BDRV_SECTOR_BITS, | |
447 | d->bytes >> BDRV_SECTOR_BITS); | |
448 | } | |
449 | ||
450 | g_free(d); | |
451 | } | |
452 | } | |
453 | ||
454 | static void update_refcount_discard(BlockDriverState *bs, | |
455 | uint64_t offset, uint64_t length) | |
456 | { | |
457 | BDRVQcowState *s = bs->opaque; | |
458 | Qcow2DiscardRegion *d, *p, *next; | |
459 | ||
460 | QTAILQ_FOREACH(d, &s->discards, next) { | |
461 | uint64_t new_start = MIN(offset, d->offset); | |
462 | uint64_t new_end = MAX(offset + length, d->offset + d->bytes); | |
463 | ||
464 | if (new_end - new_start <= length + d->bytes) { | |
465 | /* There can't be any overlap, areas ending up here have no | |
466 | * references any more and therefore shouldn't get freed another | |
467 | * time. */ | |
468 | assert(d->bytes + length == new_end - new_start); | |
469 | d->offset = new_start; | |
470 | d->bytes = new_end - new_start; | |
471 | goto found; | |
472 | } | |
473 | } | |
474 | ||
475 | d = g_malloc(sizeof(*d)); | |
476 | *d = (Qcow2DiscardRegion) { | |
477 | .bs = bs, | |
478 | .offset = offset, | |
479 | .bytes = length, | |
480 | }; | |
481 | QTAILQ_INSERT_TAIL(&s->discards, d, next); | |
482 | ||
483 | found: | |
484 | /* Merge discard requests if they are adjacent now */ | |
485 | QTAILQ_FOREACH_SAFE(p, &s->discards, next, next) { | |
486 | if (p == d | |
487 | || p->offset > d->offset + d->bytes | |
488 | || d->offset > p->offset + p->bytes) | |
489 | { | |
490 | continue; | |
491 | } | |
492 | ||
493 | /* Still no overlap possible */ | |
494 | assert(p->offset == d->offset + d->bytes | |
495 | || d->offset == p->offset + p->bytes); | |
496 | ||
497 | QTAILQ_REMOVE(&s->discards, p, next); | |
498 | d->offset = MIN(d->offset, p->offset); | |
499 | d->bytes += p->bytes; | |
500 | } | |
501 | } | |
502 | ||
f7d0fe02 | 503 | /* XXX: cache several refcount block clusters ? */ |
db3a964f | 504 | static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs, |
6cfcb9b8 | 505 | int64_t offset, int64_t length, int addend, enum qcow2_discard_type type) |
f7d0fe02 KW |
506 | { |
507 | BDRVQcowState *s = bs->opaque; | |
508 | int64_t start, last, cluster_offset; | |
29c1a730 KW |
509 | uint16_t *refcount_block = NULL; |
510 | int64_t old_table_index = -1; | |
09508d13 | 511 | int ret; |
f7d0fe02 KW |
512 | |
513 | #ifdef DEBUG_ALLOC2 | |
35ee5e39 | 514 | fprintf(stderr, "update_refcount: offset=%" PRId64 " size=%" PRId64 " addend=%d\n", |
f7d0fe02 KW |
515 | offset, length, addend); |
516 | #endif | |
7322afe7 | 517 | if (length < 0) { |
f7d0fe02 | 518 | return -EINVAL; |
7322afe7 KW |
519 | } else if (length == 0) { |
520 | return 0; | |
521 | } | |
522 | ||
29c1a730 KW |
523 | if (addend < 0) { |
524 | qcow2_cache_set_dependency(bs, s->refcount_block_cache, | |
525 | s->l2_table_cache); | |
526 | } | |
527 | ||
ac95acdb HT |
528 | start = start_of_cluster(s, offset); |
529 | last = start_of_cluster(s, offset + length - 1); | |
f7d0fe02 KW |
530 | for(cluster_offset = start; cluster_offset <= last; |
531 | cluster_offset += s->cluster_size) | |
532 | { | |
533 | int block_index, refcount; | |
534 | int64_t cluster_index = cluster_offset >> s->cluster_bits; | |
29c1a730 KW |
535 | int64_t table_index = |
536 | cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT); | |
f7d0fe02 | 537 | |
29c1a730 KW |
538 | /* Load the refcount block and allocate it if needed */ |
539 | if (table_index != old_table_index) { | |
540 | if (refcount_block) { | |
541 | ret = qcow2_cache_put(bs, s->refcount_block_cache, | |
542 | (void**) &refcount_block); | |
543 | if (ret < 0) { | |
544 | goto fail; | |
545 | } | |
546 | } | |
9923e05e | 547 | |
29c1a730 | 548 | ret = alloc_refcount_block(bs, cluster_index, &refcount_block); |
ed0df867 | 549 | if (ret < 0) { |
29c1a730 | 550 | goto fail; |
f7d0fe02 | 551 | } |
f7d0fe02 | 552 | } |
29c1a730 | 553 | old_table_index = table_index; |
f7d0fe02 | 554 | |
29c1a730 | 555 | qcow2_cache_entry_mark_dirty(s->refcount_block_cache, refcount_block); |
f7d0fe02 KW |
556 | |
557 | /* we can update the count and save it */ | |
558 | block_index = cluster_index & | |
559 | ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1); | |
f7d0fe02 | 560 | |
29c1a730 | 561 | refcount = be16_to_cpu(refcount_block[block_index]); |
f7d0fe02 | 562 | refcount += addend; |
09508d13 KW |
563 | if (refcount < 0 || refcount > 0xffff) { |
564 | ret = -EINVAL; | |
565 | goto fail; | |
566 | } | |
f7d0fe02 KW |
567 | if (refcount == 0 && cluster_index < s->free_cluster_index) { |
568 | s->free_cluster_index = cluster_index; | |
569 | } | |
29c1a730 | 570 | refcount_block[block_index] = cpu_to_be16(refcount); |
0b919fae | 571 | |
67af674e | 572 | if (refcount == 0 && s->discard_passthrough[type]) { |
0b919fae | 573 | update_refcount_discard(bs, cluster_offset, s->cluster_size); |
67af674e | 574 | } |
f7d0fe02 KW |
575 | } |
576 | ||
09508d13 KW |
577 | ret = 0; |
578 | fail: | |
0b919fae KW |
579 | if (!s->cache_discards) { |
580 | qcow2_process_discards(bs, ret); | |
581 | } | |
582 | ||
f7d0fe02 | 583 | /* Write last changed block to disk */ |
29c1a730 | 584 | if (refcount_block) { |
ed0df867 | 585 | int wret; |
29c1a730 KW |
586 | wret = qcow2_cache_put(bs, s->refcount_block_cache, |
587 | (void**) &refcount_block); | |
ed0df867 KW |
588 | if (wret < 0) { |
589 | return ret < 0 ? ret : wret; | |
f7d0fe02 KW |
590 | } |
591 | } | |
592 | ||
09508d13 KW |
593 | /* |
594 | * Try do undo any updates if an error is returned (This may succeed in | |
595 | * some cases like ENOSPC for allocating a new refcount block) | |
596 | */ | |
597 | if (ret < 0) { | |
598 | int dummy; | |
6cfcb9b8 KW |
599 | dummy = update_refcount(bs, offset, cluster_offset - offset, -addend, |
600 | QCOW2_DISCARD_NEVER); | |
83e3f76c | 601 | (void)dummy; |
09508d13 KW |
602 | } |
603 | ||
604 | return ret; | |
f7d0fe02 KW |
605 | } |
606 | ||
018faafd KW |
607 | /* |
608 | * Increases or decreases the refcount of a given cluster by one. | |
609 | * addend must be 1 or -1. | |
610 | * | |
611 | * If the return value is non-negative, it is the new refcount of the cluster. | |
612 | * If it is negative, it is -errno and indicates an error. | |
613 | */ | |
32b6444d HR |
614 | int qcow2_update_cluster_refcount(BlockDriverState *bs, |
615 | int64_t cluster_index, | |
616 | int addend, | |
617 | enum qcow2_discard_type type) | |
f7d0fe02 KW |
618 | { |
619 | BDRVQcowState *s = bs->opaque; | |
620 | int ret; | |
621 | ||
6cfcb9b8 KW |
622 | ret = update_refcount(bs, cluster_index << s->cluster_bits, 1, addend, |
623 | type); | |
f7d0fe02 KW |
624 | if (ret < 0) { |
625 | return ret; | |
626 | } | |
627 | ||
628 | return get_refcount(bs, cluster_index); | |
629 | } | |
630 | ||
631 | ||
632 | ||
633 | /*********************************************************/ | |
634 | /* cluster allocation functions */ | |
635 | ||
636 | ||
637 | ||
638 | /* return < 0 if error */ | |
bb572aef | 639 | static int64_t alloc_clusters_noref(BlockDriverState *bs, uint64_t size) |
f7d0fe02 KW |
640 | { |
641 | BDRVQcowState *s = bs->opaque; | |
bb572aef KW |
642 | uint64_t i, nb_clusters; |
643 | int refcount; | |
f7d0fe02 KW |
644 | |
645 | nb_clusters = size_to_clusters(s, size); | |
646 | retry: | |
647 | for(i = 0; i < nb_clusters; i++) { | |
bb572aef | 648 | uint64_t next_cluster_index = s->free_cluster_index++; |
2eaa8f63 KW |
649 | refcount = get_refcount(bs, next_cluster_index); |
650 | ||
651 | if (refcount < 0) { | |
652 | return refcount; | |
653 | } else if (refcount != 0) { | |
f7d0fe02 | 654 | goto retry; |
2eaa8f63 | 655 | } |
f7d0fe02 | 656 | } |
91f827dc HR |
657 | |
658 | /* Make sure that all offsets in the "allocated" range are representable | |
659 | * in an int64_t */ | |
65f33bc0 HR |
660 | if (s->free_cluster_index > 0 && |
661 | s->free_cluster_index - 1 > (INT64_MAX >> s->cluster_bits)) | |
662 | { | |
91f827dc HR |
663 | return -EFBIG; |
664 | } | |
665 | ||
f7d0fe02 | 666 | #ifdef DEBUG_ALLOC2 |
35ee5e39 | 667 | fprintf(stderr, "alloc_clusters: size=%" PRId64 " -> %" PRId64 "\n", |
f7d0fe02 KW |
668 | size, |
669 | (s->free_cluster_index - nb_clusters) << s->cluster_bits); | |
670 | #endif | |
671 | return (s->free_cluster_index - nb_clusters) << s->cluster_bits; | |
672 | } | |
673 | ||
bb572aef | 674 | int64_t qcow2_alloc_clusters(BlockDriverState *bs, uint64_t size) |
f7d0fe02 KW |
675 | { |
676 | int64_t offset; | |
db3a964f | 677 | int ret; |
f7d0fe02 | 678 | |
66f82cee | 679 | BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC); |
b106ad91 KW |
680 | do { |
681 | offset = alloc_clusters_noref(bs, size); | |
682 | if (offset < 0) { | |
683 | return offset; | |
684 | } | |
685 | ||
686 | ret = update_refcount(bs, offset, size, 1, QCOW2_DISCARD_NEVER); | |
687 | } while (ret == -EAGAIN); | |
2eaa8f63 | 688 | |
db3a964f KW |
689 | if (ret < 0) { |
690 | return ret; | |
691 | } | |
1c4c2814 | 692 | |
f7d0fe02 KW |
693 | return offset; |
694 | } | |
695 | ||
256900b1 KW |
696 | int qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset, |
697 | int nb_clusters) | |
698 | { | |
699 | BDRVQcowState *s = bs->opaque; | |
700 | uint64_t cluster_index; | |
33304ec9 HT |
701 | uint64_t i; |
702 | int refcount, ret; | |
703 | ||
704 | assert(nb_clusters >= 0); | |
705 | if (nb_clusters == 0) { | |
706 | return 0; | |
707 | } | |
256900b1 | 708 | |
b106ad91 KW |
709 | do { |
710 | /* Check how many clusters there are free */ | |
711 | cluster_index = offset >> s->cluster_bits; | |
712 | for(i = 0; i < nb_clusters; i++) { | |
713 | refcount = get_refcount(bs, cluster_index++); | |
714 | ||
715 | if (refcount < 0) { | |
716 | return refcount; | |
717 | } else if (refcount != 0) { | |
718 | break; | |
719 | } | |
256900b1 | 720 | } |
256900b1 | 721 | |
b106ad91 KW |
722 | /* And then allocate them */ |
723 | ret = update_refcount(bs, offset, i << s->cluster_bits, 1, | |
724 | QCOW2_DISCARD_NEVER); | |
725 | } while (ret == -EAGAIN); | |
f24423bd | 726 | |
256900b1 KW |
727 | if (ret < 0) { |
728 | return ret; | |
729 | } | |
730 | ||
731 | return i; | |
732 | } | |
733 | ||
f7d0fe02 KW |
734 | /* only used to allocate compressed sectors. We try to allocate |
735 | contiguous sectors. size must be <= cluster_size */ | |
ed6ccf0f | 736 | int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size) |
f7d0fe02 KW |
737 | { |
738 | BDRVQcowState *s = bs->opaque; | |
739 | int64_t offset, cluster_offset; | |
740 | int free_in_cluster; | |
741 | ||
66f82cee | 742 | BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC_BYTES); |
f7d0fe02 KW |
743 | assert(size > 0 && size <= s->cluster_size); |
744 | if (s->free_byte_offset == 0) { | |
206e6d85 SH |
745 | offset = qcow2_alloc_clusters(bs, s->cluster_size); |
746 | if (offset < 0) { | |
747 | return offset; | |
5d757b56 | 748 | } |
206e6d85 | 749 | s->free_byte_offset = offset; |
f7d0fe02 KW |
750 | } |
751 | redo: | |
752 | free_in_cluster = s->cluster_size - | |
ac95acdb | 753 | offset_into_cluster(s, s->free_byte_offset); |
f7d0fe02 KW |
754 | if (size <= free_in_cluster) { |
755 | /* enough space in current cluster */ | |
756 | offset = s->free_byte_offset; | |
757 | s->free_byte_offset += size; | |
758 | free_in_cluster -= size; | |
759 | if (free_in_cluster == 0) | |
760 | s->free_byte_offset = 0; | |
ac95acdb | 761 | if (offset_into_cluster(s, offset) != 0) |
32b6444d HR |
762 | qcow2_update_cluster_refcount(bs, offset >> s->cluster_bits, 1, |
763 | QCOW2_DISCARD_NEVER); | |
f7d0fe02 | 764 | } else { |
ed6ccf0f | 765 | offset = qcow2_alloc_clusters(bs, s->cluster_size); |
5d757b56 KW |
766 | if (offset < 0) { |
767 | return offset; | |
768 | } | |
ac95acdb | 769 | cluster_offset = start_of_cluster(s, s->free_byte_offset); |
f7d0fe02 KW |
770 | if ((cluster_offset + s->cluster_size) == offset) { |
771 | /* we are lucky: contiguous data */ | |
772 | offset = s->free_byte_offset; | |
32b6444d HR |
773 | qcow2_update_cluster_refcount(bs, offset >> s->cluster_bits, 1, |
774 | QCOW2_DISCARD_NEVER); | |
f7d0fe02 KW |
775 | s->free_byte_offset += size; |
776 | } else { | |
777 | s->free_byte_offset = offset; | |
778 | goto redo; | |
779 | } | |
780 | } | |
29216ed1 | 781 | |
c1f5bafd | 782 | /* The cluster refcount was incremented, either by qcow2_alloc_clusters() |
32b6444d HR |
783 | * or explicitly by qcow2_update_cluster_refcount(). Refcount blocks must |
784 | * be flushed before the caller's L2 table updates. | |
c1f5bafd SH |
785 | */ |
786 | qcow2_cache_set_dependency(bs, s->l2_table_cache, s->refcount_block_cache); | |
f7d0fe02 KW |
787 | return offset; |
788 | } | |
789 | ||
ed6ccf0f | 790 | void qcow2_free_clusters(BlockDriverState *bs, |
6cfcb9b8 KW |
791 | int64_t offset, int64_t size, |
792 | enum qcow2_discard_type type) | |
f7d0fe02 | 793 | { |
db3a964f KW |
794 | int ret; |
795 | ||
66f82cee | 796 | BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_FREE); |
6cfcb9b8 | 797 | ret = update_refcount(bs, offset, size, -1, type); |
db3a964f KW |
798 | if (ret < 0) { |
799 | fprintf(stderr, "qcow2_free_clusters failed: %s\n", strerror(-ret)); | |
003fad6e | 800 | /* TODO Remember the clusters to free them later and avoid leaking */ |
db3a964f | 801 | } |
f7d0fe02 KW |
802 | } |
803 | ||
45aba42f | 804 | /* |
c7a4c37a KW |
805 | * Free a cluster using its L2 entry (handles clusters of all types, e.g. |
806 | * normal cluster, compressed cluster, etc.) | |
45aba42f | 807 | */ |
6cfcb9b8 KW |
808 | void qcow2_free_any_clusters(BlockDriverState *bs, uint64_t l2_entry, |
809 | int nb_clusters, enum qcow2_discard_type type) | |
45aba42f KW |
810 | { |
811 | BDRVQcowState *s = bs->opaque; | |
812 | ||
c7a4c37a KW |
813 | switch (qcow2_get_cluster_type(l2_entry)) { |
814 | case QCOW2_CLUSTER_COMPRESSED: | |
815 | { | |
816 | int nb_csectors; | |
817 | nb_csectors = ((l2_entry >> s->csize_shift) & | |
818 | s->csize_mask) + 1; | |
819 | qcow2_free_clusters(bs, | |
820 | (l2_entry & s->cluster_offset_mask) & ~511, | |
6cfcb9b8 | 821 | nb_csectors * 512, type); |
c7a4c37a KW |
822 | } |
823 | break; | |
824 | case QCOW2_CLUSTER_NORMAL: | |
8f730dd2 HR |
825 | case QCOW2_CLUSTER_ZERO: |
826 | if (l2_entry & L2E_OFFSET_MASK) { | |
827 | qcow2_free_clusters(bs, l2_entry & L2E_OFFSET_MASK, | |
828 | nb_clusters << s->cluster_bits, type); | |
829 | } | |
c7a4c37a KW |
830 | break; |
831 | case QCOW2_CLUSTER_UNALLOCATED: | |
832 | break; | |
833 | default: | |
834 | abort(); | |
45aba42f | 835 | } |
45aba42f KW |
836 | } |
837 | ||
f7d0fe02 KW |
838 | |
839 | ||
840 | /*********************************************************/ | |
841 | /* snapshots and image creation */ | |
842 | ||
843 | ||
844 | ||
f7d0fe02 | 845 | /* update the refcounts of snapshots and the copied flag */ |
ed6ccf0f KW |
846 | int qcow2_update_snapshot_refcount(BlockDriverState *bs, |
847 | int64_t l1_table_offset, int l1_size, int addend) | |
f7d0fe02 KW |
848 | { |
849 | BDRVQcowState *s = bs->opaque; | |
850 | uint64_t *l1_table, *l2_table, l2_offset, offset, l1_size2, l1_allocated; | |
851 | int64_t old_offset, old_l2_offset; | |
93913dfd | 852 | int i, j, l1_modified = 0, nb_csectors, refcount; |
29c1a730 | 853 | int ret; |
f7d0fe02 KW |
854 | |
855 | l2_table = NULL; | |
856 | l1_table = NULL; | |
857 | l1_size2 = l1_size * sizeof(uint64_t); | |
43a0cac4 | 858 | |
0b919fae KW |
859 | s->cache_discards = true; |
860 | ||
43a0cac4 KW |
861 | /* WARNING: qcow2_snapshot_goto relies on this function not using the |
862 | * l1_table_offset when it is the current s->l1_table_offset! Be careful | |
863 | * when changing this! */ | |
f7d0fe02 | 864 | if (l1_table_offset != s->l1_table_offset) { |
6528499f | 865 | l1_table = g_malloc0(align_offset(l1_size2, 512)); |
f7d0fe02 | 866 | l1_allocated = 1; |
c2bc78b6 KW |
867 | |
868 | ret = bdrv_pread(bs->file, l1_table_offset, l1_table, l1_size2); | |
869 | if (ret < 0) { | |
f7d0fe02 | 870 | goto fail; |
93913dfd KW |
871 | } |
872 | ||
f7d0fe02 KW |
873 | for(i = 0;i < l1_size; i++) |
874 | be64_to_cpus(&l1_table[i]); | |
875 | } else { | |
876 | assert(l1_size == s->l1_size); | |
877 | l1_table = s->l1_table; | |
878 | l1_allocated = 0; | |
879 | } | |
880 | ||
f7d0fe02 KW |
881 | for(i = 0; i < l1_size; i++) { |
882 | l2_offset = l1_table[i]; | |
883 | if (l2_offset) { | |
884 | old_l2_offset = l2_offset; | |
8e37f681 | 885 | l2_offset &= L1E_OFFSET_MASK; |
29c1a730 KW |
886 | |
887 | ret = qcow2_cache_get(bs, s->l2_table_cache, l2_offset, | |
888 | (void**) &l2_table); | |
889 | if (ret < 0) { | |
f7d0fe02 | 890 | goto fail; |
29c1a730 KW |
891 | } |
892 | ||
f7d0fe02 | 893 | for(j = 0; j < s->l2_size; j++) { |
8b81a7b6 HR |
894 | uint64_t cluster_index; |
895 | ||
f7d0fe02 | 896 | offset = be64_to_cpu(l2_table[j]); |
8b81a7b6 HR |
897 | old_offset = offset; |
898 | offset &= ~QCOW_OFLAG_COPIED; | |
899 | ||
900 | switch (qcow2_get_cluster_type(offset)) { | |
901 | case QCOW2_CLUSTER_COMPRESSED: | |
f7d0fe02 KW |
902 | nb_csectors = ((offset >> s->csize_shift) & |
903 | s->csize_mask) + 1; | |
db3a964f | 904 | if (addend != 0) { |
db3a964f KW |
905 | ret = update_refcount(bs, |
906 | (offset & s->cluster_offset_mask) & ~511, | |
6cfcb9b8 KW |
907 | nb_csectors * 512, addend, |
908 | QCOW2_DISCARD_SNAPSHOT); | |
db3a964f KW |
909 | if (ret < 0) { |
910 | goto fail; | |
911 | } | |
912 | } | |
f7d0fe02 KW |
913 | /* compressed clusters are never modified */ |
914 | refcount = 2; | |
8b81a7b6 HR |
915 | break; |
916 | ||
917 | case QCOW2_CLUSTER_NORMAL: | |
918 | case QCOW2_CLUSTER_ZERO: | |
919 | cluster_index = (offset & L2E_OFFSET_MASK) >> s->cluster_bits; | |
920 | if (!cluster_index) { | |
921 | /* unallocated */ | |
922 | refcount = 0; | |
923 | break; | |
924 | } | |
f7d0fe02 | 925 | if (addend != 0) { |
32b6444d HR |
926 | refcount = qcow2_update_cluster_refcount(bs, |
927 | cluster_index, addend, | |
928 | QCOW2_DISCARD_SNAPSHOT); | |
f7d0fe02 | 929 | } else { |
8e37f681 | 930 | refcount = get_refcount(bs, cluster_index); |
f7d0fe02 | 931 | } |
018faafd KW |
932 | |
933 | if (refcount < 0) { | |
c2bc78b6 | 934 | ret = refcount; |
018faafd KW |
935 | goto fail; |
936 | } | |
8b81a7b6 | 937 | break; |
f7d0fe02 | 938 | |
8b81a7b6 HR |
939 | case QCOW2_CLUSTER_UNALLOCATED: |
940 | refcount = 0; | |
941 | break; | |
942 | ||
943 | default: | |
944 | abort(); | |
945 | } | |
946 | ||
947 | if (refcount == 1) { | |
948 | offset |= QCOW_OFLAG_COPIED; | |
949 | } | |
950 | if (offset != old_offset) { | |
951 | if (addend > 0) { | |
952 | qcow2_cache_set_dependency(bs, s->l2_table_cache, | |
953 | s->refcount_block_cache); | |
f7d0fe02 | 954 | } |
8b81a7b6 HR |
955 | l2_table[j] = cpu_to_be64(offset); |
956 | qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table); | |
f7d0fe02 KW |
957 | } |
958 | } | |
29c1a730 KW |
959 | |
960 | ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); | |
961 | if (ret < 0) { | |
962 | goto fail; | |
f7d0fe02 KW |
963 | } |
964 | ||
29c1a730 | 965 | |
f7d0fe02 | 966 | if (addend != 0) { |
32b6444d HR |
967 | refcount = qcow2_update_cluster_refcount(bs, l2_offset >> |
968 | s->cluster_bits, addend, QCOW2_DISCARD_SNAPSHOT); | |
f7d0fe02 KW |
969 | } else { |
970 | refcount = get_refcount(bs, l2_offset >> s->cluster_bits); | |
971 | } | |
018faafd | 972 | if (refcount < 0) { |
c2bc78b6 | 973 | ret = refcount; |
018faafd KW |
974 | goto fail; |
975 | } else if (refcount == 1) { | |
f7d0fe02 KW |
976 | l2_offset |= QCOW_OFLAG_COPIED; |
977 | } | |
978 | if (l2_offset != old_l2_offset) { | |
979 | l1_table[i] = l2_offset; | |
980 | l1_modified = 1; | |
981 | } | |
982 | } | |
983 | } | |
93913dfd | 984 | |
2154f24e | 985 | ret = bdrv_flush(bs); |
93913dfd KW |
986 | fail: |
987 | if (l2_table) { | |
988 | qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); | |
989 | } | |
990 | ||
0b919fae KW |
991 | s->cache_discards = false; |
992 | qcow2_process_discards(bs, ret); | |
993 | ||
43a0cac4 | 994 | /* Update L1 only if it isn't deleted anyway (addend = -1) */ |
c2b6ff51 KW |
995 | if (ret == 0 && addend >= 0 && l1_modified) { |
996 | for (i = 0; i < l1_size; i++) { | |
f7d0fe02 | 997 | cpu_to_be64s(&l1_table[i]); |
c2b6ff51 KW |
998 | } |
999 | ||
1000 | ret = bdrv_pwrite_sync(bs->file, l1_table_offset, l1_table, l1_size2); | |
1001 | ||
1002 | for (i = 0; i < l1_size; i++) { | |
f7d0fe02 | 1003 | be64_to_cpus(&l1_table[i]); |
c2b6ff51 | 1004 | } |
f7d0fe02 KW |
1005 | } |
1006 | if (l1_allocated) | |
7267c094 | 1007 | g_free(l1_table); |
93913dfd | 1008 | return ret; |
f7d0fe02 KW |
1009 | } |
1010 | ||
1011 | ||
1012 | ||
1013 | ||
1014 | /*********************************************************/ | |
1015 | /* refcount checking functions */ | |
1016 | ||
1017 | ||
1018 | ||
1019 | /* | |
1020 | * Increases the refcount for a range of clusters in a given refcount table. | |
1021 | * This is used to construct a temporary refcount table out of L1 and L2 tables | |
1022 | * which can be compared the the refcount table saved in the image. | |
1023 | * | |
9ac228e0 | 1024 | * Modifies the number of errors in res. |
f7d0fe02 | 1025 | */ |
9ac228e0 KW |
1026 | static void inc_refcounts(BlockDriverState *bs, |
1027 | BdrvCheckResult *res, | |
f7d0fe02 KW |
1028 | uint16_t *refcount_table, |
1029 | int refcount_table_size, | |
1030 | int64_t offset, int64_t size) | |
1031 | { | |
1032 | BDRVQcowState *s = bs->opaque; | |
0abe740f | 1033 | uint64_t start, last, cluster_offset, k; |
f7d0fe02 KW |
1034 | |
1035 | if (size <= 0) | |
9ac228e0 | 1036 | return; |
f7d0fe02 | 1037 | |
ac95acdb HT |
1038 | start = start_of_cluster(s, offset); |
1039 | last = start_of_cluster(s, offset + size - 1); | |
f7d0fe02 KW |
1040 | for(cluster_offset = start; cluster_offset <= last; |
1041 | cluster_offset += s->cluster_size) { | |
1042 | k = cluster_offset >> s->cluster_bits; | |
0abe740f | 1043 | if (k >= refcount_table_size) { |
9ac228e0 KW |
1044 | fprintf(stderr, "Warning: cluster offset=0x%" PRIx64 " is after " |
1045 | "the end of the image file, can't properly check refcounts.\n", | |
1046 | cluster_offset); | |
1047 | res->check_errors++; | |
f7d0fe02 KW |
1048 | } else { |
1049 | if (++refcount_table[k] == 0) { | |
1050 | fprintf(stderr, "ERROR: overflow cluster offset=0x%" PRIx64 | |
1051 | "\n", cluster_offset); | |
9ac228e0 | 1052 | res->corruptions++; |
f7d0fe02 KW |
1053 | } |
1054 | } | |
1055 | } | |
f7d0fe02 KW |
1056 | } |
1057 | ||
801f7044 SH |
1058 | /* Flags for check_refcounts_l1() and check_refcounts_l2() */ |
1059 | enum { | |
fba31bae | 1060 | CHECK_FRAG_INFO = 0x2, /* update BlockFragInfo counters */ |
801f7044 SH |
1061 | }; |
1062 | ||
f7d0fe02 KW |
1063 | /* |
1064 | * Increases the refcount in the given refcount table for the all clusters | |
1065 | * referenced in the L2 table. While doing so, performs some checks on L2 | |
1066 | * entries. | |
1067 | * | |
1068 | * Returns the number of errors found by the checks or -errno if an internal | |
1069 | * error occurred. | |
1070 | */ | |
9ac228e0 | 1071 | static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res, |
f7d0fe02 | 1072 | uint16_t *refcount_table, int refcount_table_size, int64_t l2_offset, |
801f7044 | 1073 | int flags) |
f7d0fe02 KW |
1074 | { |
1075 | BDRVQcowState *s = bs->opaque; | |
afdf0abe | 1076 | uint64_t *l2_table, l2_entry; |
fba31bae | 1077 | uint64_t next_contiguous_offset = 0; |
4f6ed88c | 1078 | int i, l2_size, nb_csectors; |
f7d0fe02 KW |
1079 | |
1080 | /* Read L2 table from disk */ | |
1081 | l2_size = s->l2_size * sizeof(uint64_t); | |
7267c094 | 1082 | l2_table = g_malloc(l2_size); |
f7d0fe02 | 1083 | |
66f82cee | 1084 | if (bdrv_pread(bs->file, l2_offset, l2_table, l2_size) != l2_size) |
f7d0fe02 KW |
1085 | goto fail; |
1086 | ||
1087 | /* Do the actual checks */ | |
1088 | for(i = 0; i < s->l2_size; i++) { | |
afdf0abe KW |
1089 | l2_entry = be64_to_cpu(l2_table[i]); |
1090 | ||
1091 | switch (qcow2_get_cluster_type(l2_entry)) { | |
1092 | case QCOW2_CLUSTER_COMPRESSED: | |
1093 | /* Compressed clusters don't have QCOW_OFLAG_COPIED */ | |
1094 | if (l2_entry & QCOW_OFLAG_COPIED) { | |
1095 | fprintf(stderr, "ERROR: cluster %" PRId64 ": " | |
1096 | "copied flag must never be set for compressed " | |
1097 | "clusters\n", l2_entry >> s->cluster_bits); | |
1098 | l2_entry &= ~QCOW_OFLAG_COPIED; | |
1099 | res->corruptions++; | |
1100 | } | |
f7d0fe02 | 1101 | |
afdf0abe KW |
1102 | /* Mark cluster as used */ |
1103 | nb_csectors = ((l2_entry >> s->csize_shift) & | |
1104 | s->csize_mask) + 1; | |
1105 | l2_entry &= s->cluster_offset_mask; | |
1106 | inc_refcounts(bs, res, refcount_table, refcount_table_size, | |
1107 | l2_entry & ~511, nb_csectors * 512); | |
fba31bae SH |
1108 | |
1109 | if (flags & CHECK_FRAG_INFO) { | |
1110 | res->bfi.allocated_clusters++; | |
4db35162 | 1111 | res->bfi.compressed_clusters++; |
fba31bae SH |
1112 | |
1113 | /* Compressed clusters are fragmented by nature. Since they | |
1114 | * take up sub-sector space but we only have sector granularity | |
1115 | * I/O we need to re-read the same sectors even for adjacent | |
1116 | * compressed clusters. | |
1117 | */ | |
1118 | res->bfi.fragmented_clusters++; | |
1119 | } | |
afdf0abe | 1120 | break; |
f7d0fe02 | 1121 | |
6377af48 KW |
1122 | case QCOW2_CLUSTER_ZERO: |
1123 | if ((l2_entry & L2E_OFFSET_MASK) == 0) { | |
1124 | break; | |
1125 | } | |
1126 | /* fall through */ | |
1127 | ||
afdf0abe KW |
1128 | case QCOW2_CLUSTER_NORMAL: |
1129 | { | |
afdf0abe | 1130 | uint64_t offset = l2_entry & L2E_OFFSET_MASK; |
f7d0fe02 | 1131 | |
fba31bae SH |
1132 | if (flags & CHECK_FRAG_INFO) { |
1133 | res->bfi.allocated_clusters++; | |
1134 | if (next_contiguous_offset && | |
1135 | offset != next_contiguous_offset) { | |
1136 | res->bfi.fragmented_clusters++; | |
1137 | } | |
1138 | next_contiguous_offset = offset + s->cluster_size; | |
1139 | } | |
1140 | ||
afdf0abe KW |
1141 | /* Mark cluster as used */ |
1142 | inc_refcounts(bs, res, refcount_table,refcount_table_size, | |
1143 | offset, s->cluster_size); | |
1144 | ||
1145 | /* Correct offsets are cluster aligned */ | |
ac95acdb | 1146 | if (offset_into_cluster(s, offset)) { |
afdf0abe KW |
1147 | fprintf(stderr, "ERROR offset=%" PRIx64 ": Cluster is not " |
1148 | "properly aligned; L2 entry corrupted.\n", offset); | |
1149 | res->corruptions++; | |
1150 | } | |
1151 | break; | |
1152 | } | |
1153 | ||
1154 | case QCOW2_CLUSTER_UNALLOCATED: | |
1155 | break; | |
1156 | ||
1157 | default: | |
1158 | abort(); | |
f7d0fe02 KW |
1159 | } |
1160 | } | |
1161 | ||
7267c094 | 1162 | g_free(l2_table); |
9ac228e0 | 1163 | return 0; |
f7d0fe02 KW |
1164 | |
1165 | fail: | |
9ac228e0 | 1166 | fprintf(stderr, "ERROR: I/O error in check_refcounts_l2\n"); |
7267c094 | 1167 | g_free(l2_table); |
f7d0fe02 KW |
1168 | return -EIO; |
1169 | } | |
1170 | ||
1171 | /* | |
1172 | * Increases the refcount for the L1 table, its L2 tables and all referenced | |
1173 | * clusters in the given refcount table. While doing so, performs some checks | |
1174 | * on L1 and L2 entries. | |
1175 | * | |
1176 | * Returns the number of errors found by the checks or -errno if an internal | |
1177 | * error occurred. | |
1178 | */ | |
1179 | static int check_refcounts_l1(BlockDriverState *bs, | |
9ac228e0 | 1180 | BdrvCheckResult *res, |
f7d0fe02 KW |
1181 | uint16_t *refcount_table, |
1182 | int refcount_table_size, | |
1183 | int64_t l1_table_offset, int l1_size, | |
801f7044 | 1184 | int flags) |
f7d0fe02 KW |
1185 | { |
1186 | BDRVQcowState *s = bs->opaque; | |
1187 | uint64_t *l1_table, l2_offset, l1_size2; | |
4f6ed88c | 1188 | int i, ret; |
f7d0fe02 KW |
1189 | |
1190 | l1_size2 = l1_size * sizeof(uint64_t); | |
1191 | ||
1192 | /* Mark L1 table as used */ | |
9ac228e0 KW |
1193 | inc_refcounts(bs, res, refcount_table, refcount_table_size, |
1194 | l1_table_offset, l1_size2); | |
f7d0fe02 KW |
1195 | |
1196 | /* Read L1 table entries from disk */ | |
702ef63f KW |
1197 | if (l1_size2 == 0) { |
1198 | l1_table = NULL; | |
1199 | } else { | |
7267c094 | 1200 | l1_table = g_malloc(l1_size2); |
66f82cee | 1201 | if (bdrv_pread(bs->file, l1_table_offset, |
702ef63f KW |
1202 | l1_table, l1_size2) != l1_size2) |
1203 | goto fail; | |
1204 | for(i = 0;i < l1_size; i++) | |
1205 | be64_to_cpus(&l1_table[i]); | |
1206 | } | |
f7d0fe02 KW |
1207 | |
1208 | /* Do the actual checks */ | |
1209 | for(i = 0; i < l1_size; i++) { | |
1210 | l2_offset = l1_table[i]; | |
1211 | if (l2_offset) { | |
f7d0fe02 | 1212 | /* Mark L2 table as used */ |
afdf0abe | 1213 | l2_offset &= L1E_OFFSET_MASK; |
9ac228e0 KW |
1214 | inc_refcounts(bs, res, refcount_table, refcount_table_size, |
1215 | l2_offset, s->cluster_size); | |
f7d0fe02 KW |
1216 | |
1217 | /* L2 tables are cluster aligned */ | |
ac95acdb | 1218 | if (offset_into_cluster(s, l2_offset)) { |
f7d0fe02 KW |
1219 | fprintf(stderr, "ERROR l2_offset=%" PRIx64 ": Table is not " |
1220 | "cluster aligned; L1 entry corrupted\n", l2_offset); | |
9ac228e0 | 1221 | res->corruptions++; |
f7d0fe02 KW |
1222 | } |
1223 | ||
1224 | /* Process and check L2 entries */ | |
9ac228e0 | 1225 | ret = check_refcounts_l2(bs, res, refcount_table, |
801f7044 | 1226 | refcount_table_size, l2_offset, flags); |
f7d0fe02 KW |
1227 | if (ret < 0) { |
1228 | goto fail; | |
1229 | } | |
f7d0fe02 KW |
1230 | } |
1231 | } | |
7267c094 | 1232 | g_free(l1_table); |
9ac228e0 | 1233 | return 0; |
f7d0fe02 KW |
1234 | |
1235 | fail: | |
1236 | fprintf(stderr, "ERROR: I/O error in check_refcounts_l1\n"); | |
9ac228e0 | 1237 | res->check_errors++; |
7267c094 | 1238 | g_free(l1_table); |
f7d0fe02 KW |
1239 | return -EIO; |
1240 | } | |
1241 | ||
4f6ed88c HR |
1242 | /* |
1243 | * Checks the OFLAG_COPIED flag for all L1 and L2 entries. | |
1244 | * | |
1245 | * This function does not print an error message nor does it increment | |
1246 | * check_errors if get_refcount fails (this is because such an error will have | |
1247 | * been already detected and sufficiently signaled by the calling function | |
1248 | * (qcow2_check_refcounts) by the time this function is called). | |
1249 | */ | |
e23e400e HR |
1250 | static int check_oflag_copied(BlockDriverState *bs, BdrvCheckResult *res, |
1251 | BdrvCheckMode fix) | |
4f6ed88c HR |
1252 | { |
1253 | BDRVQcowState *s = bs->opaque; | |
1254 | uint64_t *l2_table = qemu_blockalign(bs, s->cluster_size); | |
1255 | int ret; | |
1256 | int refcount; | |
1257 | int i, j; | |
1258 | ||
1259 | for (i = 0; i < s->l1_size; i++) { | |
1260 | uint64_t l1_entry = s->l1_table[i]; | |
1261 | uint64_t l2_offset = l1_entry & L1E_OFFSET_MASK; | |
e23e400e | 1262 | bool l2_dirty = false; |
4f6ed88c HR |
1263 | |
1264 | if (!l2_offset) { | |
1265 | continue; | |
1266 | } | |
1267 | ||
1268 | refcount = get_refcount(bs, l2_offset >> s->cluster_bits); | |
1269 | if (refcount < 0) { | |
1270 | /* don't print message nor increment check_errors */ | |
1271 | continue; | |
1272 | } | |
1273 | if ((refcount == 1) != ((l1_entry & QCOW_OFLAG_COPIED) != 0)) { | |
e23e400e | 1274 | fprintf(stderr, "%s OFLAG_COPIED L2 cluster: l1_index=%d " |
4f6ed88c | 1275 | "l1_entry=%" PRIx64 " refcount=%d\n", |
e23e400e HR |
1276 | fix & BDRV_FIX_ERRORS ? "Repairing" : |
1277 | "ERROR", | |
4f6ed88c | 1278 | i, l1_entry, refcount); |
e23e400e HR |
1279 | if (fix & BDRV_FIX_ERRORS) { |
1280 | s->l1_table[i] = refcount == 1 | |
1281 | ? l1_entry | QCOW_OFLAG_COPIED | |
1282 | : l1_entry & ~QCOW_OFLAG_COPIED; | |
1283 | ret = qcow2_write_l1_entry(bs, i); | |
1284 | if (ret < 0) { | |
1285 | res->check_errors++; | |
1286 | goto fail; | |
1287 | } | |
1288 | res->corruptions_fixed++; | |
1289 | } else { | |
1290 | res->corruptions++; | |
1291 | } | |
4f6ed88c HR |
1292 | } |
1293 | ||
1294 | ret = bdrv_pread(bs->file, l2_offset, l2_table, | |
1295 | s->l2_size * sizeof(uint64_t)); | |
1296 | if (ret < 0) { | |
1297 | fprintf(stderr, "ERROR: Could not read L2 table: %s\n", | |
1298 | strerror(-ret)); | |
1299 | res->check_errors++; | |
1300 | goto fail; | |
1301 | } | |
1302 | ||
1303 | for (j = 0; j < s->l2_size; j++) { | |
1304 | uint64_t l2_entry = be64_to_cpu(l2_table[j]); | |
1305 | uint64_t data_offset = l2_entry & L2E_OFFSET_MASK; | |
1306 | int cluster_type = qcow2_get_cluster_type(l2_entry); | |
1307 | ||
1308 | if ((cluster_type == QCOW2_CLUSTER_NORMAL) || | |
1309 | ((cluster_type == QCOW2_CLUSTER_ZERO) && (data_offset != 0))) { | |
1310 | refcount = get_refcount(bs, data_offset >> s->cluster_bits); | |
1311 | if (refcount < 0) { | |
1312 | /* don't print message nor increment check_errors */ | |
1313 | continue; | |
1314 | } | |
1315 | if ((refcount == 1) != ((l2_entry & QCOW_OFLAG_COPIED) != 0)) { | |
e23e400e | 1316 | fprintf(stderr, "%s OFLAG_COPIED data cluster: " |
4f6ed88c | 1317 | "l2_entry=%" PRIx64 " refcount=%d\n", |
e23e400e HR |
1318 | fix & BDRV_FIX_ERRORS ? "Repairing" : |
1319 | "ERROR", | |
4f6ed88c | 1320 | l2_entry, refcount); |
e23e400e HR |
1321 | if (fix & BDRV_FIX_ERRORS) { |
1322 | l2_table[j] = cpu_to_be64(refcount == 1 | |
1323 | ? l2_entry | QCOW_OFLAG_COPIED | |
1324 | : l2_entry & ~QCOW_OFLAG_COPIED); | |
1325 | l2_dirty = true; | |
1326 | res->corruptions_fixed++; | |
1327 | } else { | |
1328 | res->corruptions++; | |
1329 | } | |
4f6ed88c HR |
1330 | } |
1331 | } | |
1332 | } | |
e23e400e HR |
1333 | |
1334 | if (l2_dirty) { | |
231bb267 HR |
1335 | ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_ACTIVE_L2, |
1336 | l2_offset, s->cluster_size); | |
e23e400e HR |
1337 | if (ret < 0) { |
1338 | fprintf(stderr, "ERROR: Could not write L2 table; metadata " | |
1339 | "overlap check failed: %s\n", strerror(-ret)); | |
1340 | res->check_errors++; | |
1341 | goto fail; | |
1342 | } | |
1343 | ||
1344 | ret = bdrv_pwrite(bs->file, l2_offset, l2_table, s->cluster_size); | |
1345 | if (ret < 0) { | |
1346 | fprintf(stderr, "ERROR: Could not write L2 table: %s\n", | |
1347 | strerror(-ret)); | |
1348 | res->check_errors++; | |
1349 | goto fail; | |
1350 | } | |
1351 | } | |
4f6ed88c HR |
1352 | } |
1353 | ||
1354 | ret = 0; | |
1355 | ||
1356 | fail: | |
1357 | qemu_vfree(l2_table); | |
1358 | return ret; | |
1359 | } | |
1360 | ||
afa50193 HR |
1361 | /* |
1362 | * Writes one sector of the refcount table to the disk | |
1363 | */ | |
1364 | #define RT_ENTRIES_PER_SECTOR (512 / sizeof(uint64_t)) | |
1365 | static int write_reftable_entry(BlockDriverState *bs, int rt_index) | |
1366 | { | |
1367 | BDRVQcowState *s = bs->opaque; | |
1368 | uint64_t buf[RT_ENTRIES_PER_SECTOR]; | |
1369 | int rt_start_index; | |
1370 | int i, ret; | |
1371 | ||
1372 | rt_start_index = rt_index & ~(RT_ENTRIES_PER_SECTOR - 1); | |
1373 | for (i = 0; i < RT_ENTRIES_PER_SECTOR; i++) { | |
1374 | buf[i] = cpu_to_be64(s->refcount_table[rt_start_index + i]); | |
1375 | } | |
1376 | ||
231bb267 | 1377 | ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_REFCOUNT_TABLE, |
afa50193 HR |
1378 | s->refcount_table_offset + rt_start_index * sizeof(uint64_t), |
1379 | sizeof(buf)); | |
1380 | if (ret < 0) { | |
1381 | return ret; | |
1382 | } | |
1383 | ||
1384 | BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_UPDATE); | |
1385 | ret = bdrv_pwrite_sync(bs->file, s->refcount_table_offset + | |
1386 | rt_start_index * sizeof(uint64_t), buf, sizeof(buf)); | |
1387 | if (ret < 0) { | |
1388 | return ret; | |
1389 | } | |
1390 | ||
1391 | return 0; | |
1392 | } | |
1393 | ||
1394 | /* | |
1395 | * Allocates a new cluster for the given refcount block (represented by its | |
1396 | * offset in the image file) and copies the current content there. This function | |
1397 | * does _not_ decrement the reference count for the currently occupied cluster. | |
1398 | * | |
1399 | * This function prints an informative message to stderr on error (and returns | |
8a15b813 | 1400 | * -errno); on success, the offset of the newly allocated cluster is returned. |
afa50193 HR |
1401 | */ |
1402 | static int64_t realloc_refcount_block(BlockDriverState *bs, int reftable_index, | |
1403 | uint64_t offset) | |
1404 | { | |
1405 | BDRVQcowState *s = bs->opaque; | |
1406 | int64_t new_offset = 0; | |
1407 | void *refcount_block = NULL; | |
1408 | int ret; | |
1409 | ||
1410 | /* allocate new refcount block */ | |
1411 | new_offset = qcow2_alloc_clusters(bs, s->cluster_size); | |
1412 | if (new_offset < 0) { | |
1413 | fprintf(stderr, "Could not allocate new cluster: %s\n", | |
1414 | strerror(-new_offset)); | |
1415 | ret = new_offset; | |
a134d90f | 1416 | goto done; |
afa50193 HR |
1417 | } |
1418 | ||
1419 | /* fetch current refcount block content */ | |
1420 | ret = qcow2_cache_get(bs, s->refcount_block_cache, offset, &refcount_block); | |
1421 | if (ret < 0) { | |
1422 | fprintf(stderr, "Could not fetch refcount block: %s\n", strerror(-ret)); | |
a134d90f | 1423 | goto fail_free_cluster; |
afa50193 HR |
1424 | } |
1425 | ||
1426 | /* new block has not yet been entered into refcount table, therefore it is | |
1427 | * no refcount block yet (regarding this check) */ | |
231bb267 | 1428 | ret = qcow2_pre_write_overlap_check(bs, 0, new_offset, s->cluster_size); |
afa50193 HR |
1429 | if (ret < 0) { |
1430 | fprintf(stderr, "Could not write refcount block; metadata overlap " | |
1431 | "check failed: %s\n", strerror(-ret)); | |
1432 | /* the image will be marked corrupt, so don't even attempt on freeing | |
1433 | * the cluster */ | |
a134d90f | 1434 | goto done; |
afa50193 HR |
1435 | } |
1436 | ||
1437 | /* write to new block */ | |
1438 | ret = bdrv_write(bs->file, new_offset / BDRV_SECTOR_SIZE, refcount_block, | |
1439 | s->cluster_sectors); | |
1440 | if (ret < 0) { | |
1441 | fprintf(stderr, "Could not write refcount block: %s\n", strerror(-ret)); | |
a134d90f | 1442 | goto fail_free_cluster; |
afa50193 HR |
1443 | } |
1444 | ||
1445 | /* update refcount table */ | |
ac95acdb | 1446 | assert(!offset_into_cluster(s, new_offset)); |
afa50193 HR |
1447 | s->refcount_table[reftable_index] = new_offset; |
1448 | ret = write_reftable_entry(bs, reftable_index); | |
1449 | if (ret < 0) { | |
1450 | fprintf(stderr, "Could not update refcount table: %s\n", | |
1451 | strerror(-ret)); | |
a134d90f | 1452 | goto fail_free_cluster; |
afa50193 HR |
1453 | } |
1454 | ||
a134d90f HR |
1455 | goto done; |
1456 | ||
1457 | fail_free_cluster: | |
1458 | qcow2_free_clusters(bs, new_offset, s->cluster_size, QCOW2_DISCARD_OTHER); | |
1459 | ||
1460 | done: | |
afa50193 | 1461 | if (refcount_block) { |
a134d90f HR |
1462 | /* This should never fail, as it would only do so if the given refcount |
1463 | * block cannot be found in the cache. As this is impossible as long as | |
1464 | * there are no bugs, assert the success. */ | |
1465 | int tmp = qcow2_cache_put(bs, s->refcount_block_cache, &refcount_block); | |
1466 | assert(tmp == 0); | |
afa50193 | 1467 | } |
a134d90f | 1468 | |
afa50193 HR |
1469 | if (ret < 0) { |
1470 | return ret; | |
1471 | } | |
a134d90f | 1472 | |
afa50193 HR |
1473 | return new_offset; |
1474 | } | |
1475 | ||
f7d0fe02 KW |
1476 | /* |
1477 | * Checks an image for refcount consistency. | |
1478 | * | |
1479 | * Returns 0 if no errors are found, the number of errors in case the image is | |
a1c7273b | 1480 | * detected as corrupted, and -errno when an internal error occurred. |
f7d0fe02 | 1481 | */ |
166acf54 KW |
1482 | int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res, |
1483 | BdrvCheckMode fix) | |
f7d0fe02 KW |
1484 | { |
1485 | BDRVQcowState *s = bs->opaque; | |
0abe740f KW |
1486 | int64_t size, i, highest_cluster, nb_clusters; |
1487 | int refcount1, refcount2; | |
f7d0fe02 KW |
1488 | QCowSnapshot *sn; |
1489 | uint16_t *refcount_table; | |
9ac228e0 | 1490 | int ret; |
f7d0fe02 | 1491 | |
66f82cee | 1492 | size = bdrv_getlength(bs->file); |
a49139af HR |
1493 | if (size < 0) { |
1494 | res->check_errors++; | |
1495 | return size; | |
1496 | } | |
1497 | ||
f7d0fe02 | 1498 | nb_clusters = size_to_clusters(s, size); |
0abe740f KW |
1499 | if (nb_clusters > INT_MAX) { |
1500 | res->check_errors++; | |
1501 | return -EFBIG; | |
1502 | } | |
1503 | ||
7267c094 | 1504 | refcount_table = g_malloc0(nb_clusters * sizeof(uint16_t)); |
f7d0fe02 | 1505 | |
c349ca4b KW |
1506 | res->bfi.total_clusters = |
1507 | size_to_clusters(s, bs->total_sectors * BDRV_SECTOR_SIZE); | |
1508 | ||
f7d0fe02 | 1509 | /* header */ |
9ac228e0 KW |
1510 | inc_refcounts(bs, res, refcount_table, nb_clusters, |
1511 | 0, s->cluster_size); | |
f7d0fe02 KW |
1512 | |
1513 | /* current L1 table */ | |
9ac228e0 | 1514 | ret = check_refcounts_l1(bs, res, refcount_table, nb_clusters, |
db074901 | 1515 | s->l1_table_offset, s->l1_size, CHECK_FRAG_INFO); |
f7d0fe02 | 1516 | if (ret < 0) { |
80fa3341 | 1517 | goto fail; |
f7d0fe02 | 1518 | } |
f7d0fe02 KW |
1519 | |
1520 | /* snapshots */ | |
1521 | for(i = 0; i < s->nb_snapshots; i++) { | |
1522 | sn = s->snapshots + i; | |
9ac228e0 KW |
1523 | ret = check_refcounts_l1(bs, res, refcount_table, nb_clusters, |
1524 | sn->l1_table_offset, sn->l1_size, 0); | |
1525 | if (ret < 0) { | |
80fa3341 | 1526 | goto fail; |
9ac228e0 | 1527 | } |
f7d0fe02 | 1528 | } |
9ac228e0 KW |
1529 | inc_refcounts(bs, res, refcount_table, nb_clusters, |
1530 | s->snapshots_offset, s->snapshots_size); | |
f7d0fe02 KW |
1531 | |
1532 | /* refcount data */ | |
9ac228e0 KW |
1533 | inc_refcounts(bs, res, refcount_table, nb_clusters, |
1534 | s->refcount_table_offset, | |
1535 | s->refcount_table_size * sizeof(uint64_t)); | |
1536 | ||
f7d0fe02 | 1537 | for(i = 0; i < s->refcount_table_size; i++) { |
6882c8fa | 1538 | uint64_t offset, cluster; |
f7d0fe02 | 1539 | offset = s->refcount_table[i]; |
6882c8fa | 1540 | cluster = offset >> s->cluster_bits; |
746c3cb5 KW |
1541 | |
1542 | /* Refcount blocks are cluster aligned */ | |
ac95acdb | 1543 | if (offset_into_cluster(s, offset)) { |
166acf54 | 1544 | fprintf(stderr, "ERROR refcount block %" PRId64 " is not " |
746c3cb5 | 1545 | "cluster aligned; refcount table entry corrupted\n", i); |
9ac228e0 | 1546 | res->corruptions++; |
6882c8fa KW |
1547 | continue; |
1548 | } | |
1549 | ||
1550 | if (cluster >= nb_clusters) { | |
166acf54 KW |
1551 | fprintf(stderr, "ERROR refcount block %" PRId64 |
1552 | " is outside image\n", i); | |
9ac228e0 | 1553 | res->corruptions++; |
6882c8fa | 1554 | continue; |
746c3cb5 KW |
1555 | } |
1556 | ||
f7d0fe02 | 1557 | if (offset != 0) { |
9ac228e0 KW |
1558 | inc_refcounts(bs, res, refcount_table, nb_clusters, |
1559 | offset, s->cluster_size); | |
6882c8fa | 1560 | if (refcount_table[cluster] != 1) { |
afa50193 | 1561 | fprintf(stderr, "%s refcount block %" PRId64 |
166acf54 | 1562 | " refcount=%d\n", |
afa50193 HR |
1563 | fix & BDRV_FIX_ERRORS ? "Repairing" : |
1564 | "ERROR", | |
6882c8fa | 1565 | i, refcount_table[cluster]); |
afa50193 HR |
1566 | |
1567 | if (fix & BDRV_FIX_ERRORS) { | |
1568 | int64_t new_offset; | |
1569 | ||
1570 | new_offset = realloc_refcount_block(bs, i, offset); | |
1571 | if (new_offset < 0) { | |
1572 | res->corruptions++; | |
1573 | continue; | |
1574 | } | |
1575 | ||
1576 | /* update refcounts */ | |
1577 | if ((new_offset >> s->cluster_bits) >= nb_clusters) { | |
1578 | /* increase refcount_table size if necessary */ | |
1579 | int old_nb_clusters = nb_clusters; | |
1580 | nb_clusters = (new_offset >> s->cluster_bits) + 1; | |
1581 | refcount_table = g_realloc(refcount_table, | |
1582 | nb_clusters * sizeof(uint16_t)); | |
1583 | memset(&refcount_table[old_nb_clusters], 0, (nb_clusters | |
1584 | - old_nb_clusters) * sizeof(uint16_t)); | |
1585 | } | |
1586 | refcount_table[cluster]--; | |
1587 | inc_refcounts(bs, res, refcount_table, nb_clusters, | |
1588 | new_offset, s->cluster_size); | |
1589 | ||
1590 | res->corruptions_fixed++; | |
1591 | } else { | |
1592 | res->corruptions++; | |
1593 | } | |
746c3cb5 | 1594 | } |
f7d0fe02 KW |
1595 | } |
1596 | } | |
1597 | ||
1598 | /* compare ref counts */ | |
c6bb9ad1 | 1599 | for (i = 0, highest_cluster = 0; i < nb_clusters; i++) { |
f7d0fe02 | 1600 | refcount1 = get_refcount(bs, i); |
018faafd | 1601 | if (refcount1 < 0) { |
166acf54 | 1602 | fprintf(stderr, "Can't get refcount for cluster %" PRId64 ": %s\n", |
018faafd | 1603 | i, strerror(-refcount1)); |
9ac228e0 | 1604 | res->check_errors++; |
f74550fd | 1605 | continue; |
018faafd KW |
1606 | } |
1607 | ||
f7d0fe02 | 1608 | refcount2 = refcount_table[i]; |
c6bb9ad1 FS |
1609 | |
1610 | if (refcount1 > 0 || refcount2 > 0) { | |
1611 | highest_cluster = i; | |
1612 | } | |
1613 | ||
f7d0fe02 | 1614 | if (refcount1 != refcount2) { |
166acf54 KW |
1615 | |
1616 | /* Check if we're allowed to fix the mismatch */ | |
1617 | int *num_fixed = NULL; | |
1618 | if (refcount1 > refcount2 && (fix & BDRV_FIX_LEAKS)) { | |
1619 | num_fixed = &res->leaks_fixed; | |
1620 | } else if (refcount1 < refcount2 && (fix & BDRV_FIX_ERRORS)) { | |
1621 | num_fixed = &res->corruptions_fixed; | |
1622 | } | |
1623 | ||
1624 | fprintf(stderr, "%s cluster %" PRId64 " refcount=%d reference=%d\n", | |
1625 | num_fixed != NULL ? "Repairing" : | |
1626 | refcount1 < refcount2 ? "ERROR" : | |
1627 | "Leaked", | |
f7d0fe02 | 1628 | i, refcount1, refcount2); |
166acf54 KW |
1629 | |
1630 | if (num_fixed) { | |
1631 | ret = update_refcount(bs, i << s->cluster_bits, 1, | |
6cfcb9b8 KW |
1632 | refcount2 - refcount1, |
1633 | QCOW2_DISCARD_ALWAYS); | |
166acf54 KW |
1634 | if (ret >= 0) { |
1635 | (*num_fixed)++; | |
1636 | continue; | |
1637 | } | |
1638 | } | |
1639 | ||
1640 | /* And if we couldn't, print an error */ | |
9ac228e0 KW |
1641 | if (refcount1 < refcount2) { |
1642 | res->corruptions++; | |
1643 | } else { | |
1644 | res->leaks++; | |
1645 | } | |
f7d0fe02 KW |
1646 | } |
1647 | } | |
1648 | ||
4f6ed88c | 1649 | /* check OFLAG_COPIED */ |
e23e400e | 1650 | ret = check_oflag_copied(bs, res, fix); |
4f6ed88c HR |
1651 | if (ret < 0) { |
1652 | goto fail; | |
1653 | } | |
1654 | ||
c6bb9ad1 | 1655 | res->image_end_offset = (highest_cluster + 1) * s->cluster_size; |
80fa3341 KW |
1656 | ret = 0; |
1657 | ||
1658 | fail: | |
7267c094 | 1659 | g_free(refcount_table); |
f7d0fe02 | 1660 | |
80fa3341 | 1661 | return ret; |
f7d0fe02 KW |
1662 | } |
1663 | ||
a40f1c2a HR |
1664 | #define overlaps_with(ofs, sz) \ |
1665 | ranges_overlap(offset, size, ofs, sz) | |
1666 | ||
1667 | /* | |
1668 | * Checks if the given offset into the image file is actually free to use by | |
1669 | * looking for overlaps with important metadata sections (L1/L2 tables etc.), | |
1670 | * i.e. a sanity check without relying on the refcount tables. | |
1671 | * | |
231bb267 HR |
1672 | * The ign parameter specifies what checks not to perform (being a bitmask of |
1673 | * QCow2MetadataOverlap values), i.e., what sections to ignore. | |
a40f1c2a HR |
1674 | * |
1675 | * Returns: | |
1676 | * - 0 if writing to this offset will not affect the mentioned metadata | |
1677 | * - a positive QCow2MetadataOverlap value indicating one overlapping section | |
1678 | * - a negative value (-errno) indicating an error while performing a check, | |
1679 | * e.g. when bdrv_read failed on QCOW2_OL_INACTIVE_L2 | |
1680 | */ | |
231bb267 | 1681 | int qcow2_check_metadata_overlap(BlockDriverState *bs, int ign, int64_t offset, |
a40f1c2a HR |
1682 | int64_t size) |
1683 | { | |
1684 | BDRVQcowState *s = bs->opaque; | |
3e355390 | 1685 | int chk = s->overlap_check & ~ign; |
a40f1c2a HR |
1686 | int i, j; |
1687 | ||
1688 | if (!size) { | |
1689 | return 0; | |
1690 | } | |
1691 | ||
1692 | if (chk & QCOW2_OL_MAIN_HEADER) { | |
1693 | if (offset < s->cluster_size) { | |
1694 | return QCOW2_OL_MAIN_HEADER; | |
1695 | } | |
1696 | } | |
1697 | ||
1698 | /* align range to test to cluster boundaries */ | |
1699 | size = align_offset(offset_into_cluster(s, offset) + size, s->cluster_size); | |
1700 | offset = start_of_cluster(s, offset); | |
1701 | ||
1702 | if ((chk & QCOW2_OL_ACTIVE_L1) && s->l1_size) { | |
1703 | if (overlaps_with(s->l1_table_offset, s->l1_size * sizeof(uint64_t))) { | |
1704 | return QCOW2_OL_ACTIVE_L1; | |
1705 | } | |
1706 | } | |
1707 | ||
1708 | if ((chk & QCOW2_OL_REFCOUNT_TABLE) && s->refcount_table_size) { | |
1709 | if (overlaps_with(s->refcount_table_offset, | |
1710 | s->refcount_table_size * sizeof(uint64_t))) { | |
1711 | return QCOW2_OL_REFCOUNT_TABLE; | |
1712 | } | |
1713 | } | |
1714 | ||
1715 | if ((chk & QCOW2_OL_SNAPSHOT_TABLE) && s->snapshots_size) { | |
1716 | if (overlaps_with(s->snapshots_offset, s->snapshots_size)) { | |
1717 | return QCOW2_OL_SNAPSHOT_TABLE; | |
1718 | } | |
1719 | } | |
1720 | ||
1721 | if ((chk & QCOW2_OL_INACTIVE_L1) && s->snapshots) { | |
1722 | for (i = 0; i < s->nb_snapshots; i++) { | |
1723 | if (s->snapshots[i].l1_size && | |
1724 | overlaps_with(s->snapshots[i].l1_table_offset, | |
1725 | s->snapshots[i].l1_size * sizeof(uint64_t))) { | |
1726 | return QCOW2_OL_INACTIVE_L1; | |
1727 | } | |
1728 | } | |
1729 | } | |
1730 | ||
1731 | if ((chk & QCOW2_OL_ACTIVE_L2) && s->l1_table) { | |
1732 | for (i = 0; i < s->l1_size; i++) { | |
1733 | if ((s->l1_table[i] & L1E_OFFSET_MASK) && | |
1734 | overlaps_with(s->l1_table[i] & L1E_OFFSET_MASK, | |
1735 | s->cluster_size)) { | |
1736 | return QCOW2_OL_ACTIVE_L2; | |
1737 | } | |
1738 | } | |
1739 | } | |
1740 | ||
1741 | if ((chk & QCOW2_OL_REFCOUNT_BLOCK) && s->refcount_table) { | |
1742 | for (i = 0; i < s->refcount_table_size; i++) { | |
1743 | if ((s->refcount_table[i] & REFT_OFFSET_MASK) && | |
1744 | overlaps_with(s->refcount_table[i] & REFT_OFFSET_MASK, | |
1745 | s->cluster_size)) { | |
1746 | return QCOW2_OL_REFCOUNT_BLOCK; | |
1747 | } | |
1748 | } | |
1749 | } | |
1750 | ||
1751 | if ((chk & QCOW2_OL_INACTIVE_L2) && s->snapshots) { | |
1752 | for (i = 0; i < s->nb_snapshots; i++) { | |
1753 | uint64_t l1_ofs = s->snapshots[i].l1_table_offset; | |
1754 | uint32_t l1_sz = s->snapshots[i].l1_size; | |
998b959c HR |
1755 | uint64_t l1_sz2 = l1_sz * sizeof(uint64_t); |
1756 | uint64_t *l1 = g_malloc(l1_sz2); | |
a40f1c2a HR |
1757 | int ret; |
1758 | ||
998b959c | 1759 | ret = bdrv_pread(bs->file, l1_ofs, l1, l1_sz2); |
a40f1c2a HR |
1760 | if (ret < 0) { |
1761 | g_free(l1); | |
1762 | return ret; | |
1763 | } | |
1764 | ||
1765 | for (j = 0; j < l1_sz; j++) { | |
1e242b55 HR |
1766 | uint64_t l2_ofs = be64_to_cpu(l1[j]) & L1E_OFFSET_MASK; |
1767 | if (l2_ofs && overlaps_with(l2_ofs, s->cluster_size)) { | |
a40f1c2a HR |
1768 | g_free(l1); |
1769 | return QCOW2_OL_INACTIVE_L2; | |
1770 | } | |
1771 | } | |
1772 | ||
1773 | g_free(l1); | |
1774 | } | |
1775 | } | |
1776 | ||
1777 | return 0; | |
1778 | } | |
1779 | ||
1780 | static const char *metadata_ol_names[] = { | |
1781 | [QCOW2_OL_MAIN_HEADER_BITNR] = "qcow2_header", | |
1782 | [QCOW2_OL_ACTIVE_L1_BITNR] = "active L1 table", | |
1783 | [QCOW2_OL_ACTIVE_L2_BITNR] = "active L2 table", | |
1784 | [QCOW2_OL_REFCOUNT_TABLE_BITNR] = "refcount table", | |
1785 | [QCOW2_OL_REFCOUNT_BLOCK_BITNR] = "refcount block", | |
1786 | [QCOW2_OL_SNAPSHOT_TABLE_BITNR] = "snapshot table", | |
1787 | [QCOW2_OL_INACTIVE_L1_BITNR] = "inactive L1 table", | |
1788 | [QCOW2_OL_INACTIVE_L2_BITNR] = "inactive L2 table", | |
1789 | }; | |
1790 | ||
1791 | /* | |
1792 | * First performs a check for metadata overlaps (through | |
1793 | * qcow2_check_metadata_overlap); if that fails with a negative value (error | |
1794 | * while performing a check), that value is returned. If an impending overlap | |
1795 | * is detected, the BDS will be made unusable, the qcow2 file marked corrupt | |
1796 | * and -EIO returned. | |
1797 | * | |
1798 | * Returns 0 if there were neither overlaps nor errors while checking for | |
1799 | * overlaps; or a negative value (-errno) on error. | |
1800 | */ | |
231bb267 | 1801 | int qcow2_pre_write_overlap_check(BlockDriverState *bs, int ign, int64_t offset, |
a40f1c2a HR |
1802 | int64_t size) |
1803 | { | |
231bb267 | 1804 | int ret = qcow2_check_metadata_overlap(bs, ign, offset, size); |
a40f1c2a HR |
1805 | |
1806 | if (ret < 0) { | |
1807 | return ret; | |
1808 | } else if (ret > 0) { | |
1809 | int metadata_ol_bitnr = ffs(ret) - 1; | |
1810 | char *message; | |
a40f1c2a HR |
1811 | |
1812 | assert(metadata_ol_bitnr < QCOW2_OL_MAX_BITNR); | |
1813 | ||
1814 | fprintf(stderr, "qcow2: Preventing invalid write on metadata (overlaps " | |
1815 | "with %s); image marked as corrupt.\n", | |
1816 | metadata_ol_names[metadata_ol_bitnr]); | |
1817 | message = g_strdup_printf("Prevented %s overwrite", | |
1818 | metadata_ol_names[metadata_ol_bitnr]); | |
c120f0fa WX |
1819 | qapi_event_send_block_image_corrupted(bdrv_get_device_name(bs), |
1820 | message, | |
1821 | true, | |
1822 | offset, | |
1823 | true, | |
1824 | size, | |
1825 | &error_abort); | |
a40f1c2a | 1826 | g_free(message); |
a40f1c2a HR |
1827 | |
1828 | qcow2_mark_corrupt(bs); | |
1829 | bs->drv = NULL; /* make BDS unusable */ | |
1830 | return -EIO; | |
1831 | } | |
1832 | ||
1833 | return 0; | |
1834 | } |