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45aba42f 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 | ||
80c71a24 | 25 | #include "qemu/osdep.h" |
45aba42f KW |
26 | #include <zlib.h> |
27 | ||
da34e65c | 28 | #include "qapi/error.h" |
45aba42f | 29 | #include "qemu-common.h" |
737e150e | 30 | #include "block/block_int.h" |
45aba42f | 31 | #include "block/qcow2.h" |
58369e22 | 32 | #include "qemu/bswap.h" |
3cce16f4 | 33 | #include "trace.h" |
45aba42f | 34 | |
46b732cd PB |
35 | int qcow2_shrink_l1_table(BlockDriverState *bs, uint64_t exact_size) |
36 | { | |
37 | BDRVQcow2State *s = bs->opaque; | |
38 | int new_l1_size, i, ret; | |
39 | ||
40 | if (exact_size >= s->l1_size) { | |
41 | return 0; | |
42 | } | |
43 | ||
44 | new_l1_size = exact_size; | |
45 | ||
46 | #ifdef DEBUG_ALLOC2 | |
47 | fprintf(stderr, "shrink l1_table from %d to %d\n", s->l1_size, new_l1_size); | |
48 | #endif | |
49 | ||
50 | BLKDBG_EVENT(bs->file, BLKDBG_L1_SHRINK_WRITE_TABLE); | |
51 | ret = bdrv_pwrite_zeroes(bs->file, s->l1_table_offset + | |
52 | new_l1_size * sizeof(uint64_t), | |
53 | (s->l1_size - new_l1_size) * sizeof(uint64_t), 0); | |
54 | if (ret < 0) { | |
55 | goto fail; | |
56 | } | |
57 | ||
58 | ret = bdrv_flush(bs->file->bs); | |
59 | if (ret < 0) { | |
60 | goto fail; | |
61 | } | |
62 | ||
63 | BLKDBG_EVENT(bs->file, BLKDBG_L1_SHRINK_FREE_L2_CLUSTERS); | |
64 | for (i = s->l1_size - 1; i > new_l1_size - 1; i--) { | |
65 | if ((s->l1_table[i] & L1E_OFFSET_MASK) == 0) { | |
66 | continue; | |
67 | } | |
68 | qcow2_free_clusters(bs, s->l1_table[i] & L1E_OFFSET_MASK, | |
69 | s->cluster_size, QCOW2_DISCARD_ALWAYS); | |
70 | s->l1_table[i] = 0; | |
71 | } | |
72 | return 0; | |
73 | ||
74 | fail: | |
75 | /* | |
76 | * If the write in the l1_table failed the image may contain a partially | |
77 | * overwritten l1_table. In this case it would be better to clear the | |
78 | * l1_table in memory to avoid possible image corruption. | |
79 | */ | |
80 | memset(s->l1_table + new_l1_size, 0, | |
81 | (s->l1_size - new_l1_size) * sizeof(uint64_t)); | |
82 | return ret; | |
83 | } | |
84 | ||
2cf7cfa1 KW |
85 | int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size, |
86 | bool exact_size) | |
45aba42f | 87 | { |
ff99129a | 88 | BDRVQcow2State *s = bs->opaque; |
2cf7cfa1 | 89 | int new_l1_size2, ret, i; |
45aba42f | 90 | uint64_t *new_l1_table; |
fda74f82 | 91 | int64_t old_l1_table_offset, old_l1_size; |
2cf7cfa1 | 92 | int64_t new_l1_table_offset, new_l1_size; |
45aba42f KW |
93 | uint8_t data[12]; |
94 | ||
72893756 | 95 | if (min_size <= s->l1_size) |
45aba42f | 96 | return 0; |
72893756 | 97 | |
b93f9950 HR |
98 | /* Do a sanity check on min_size before trying to calculate new_l1_size |
99 | * (this prevents overflows during the while loop for the calculation of | |
100 | * new_l1_size) */ | |
101 | if (min_size > INT_MAX / sizeof(uint64_t)) { | |
102 | return -EFBIG; | |
103 | } | |
104 | ||
72893756 SH |
105 | if (exact_size) { |
106 | new_l1_size = min_size; | |
107 | } else { | |
108 | /* Bump size up to reduce the number of times we have to grow */ | |
109 | new_l1_size = s->l1_size; | |
110 | if (new_l1_size == 0) { | |
111 | new_l1_size = 1; | |
112 | } | |
113 | while (min_size > new_l1_size) { | |
21cf3e12 | 114 | new_l1_size = DIV_ROUND_UP(new_l1_size * 3, 2); |
72893756 | 115 | } |
45aba42f | 116 | } |
72893756 | 117 | |
84c26520 HR |
118 | QEMU_BUILD_BUG_ON(QCOW_MAX_L1_SIZE > INT_MAX); |
119 | if (new_l1_size > QCOW_MAX_L1_SIZE / sizeof(uint64_t)) { | |
2cf7cfa1 KW |
120 | return -EFBIG; |
121 | } | |
122 | ||
45aba42f | 123 | #ifdef DEBUG_ALLOC2 |
2cf7cfa1 KW |
124 | fprintf(stderr, "grow l1_table from %d to %" PRId64 "\n", |
125 | s->l1_size, new_l1_size); | |
45aba42f KW |
126 | #endif |
127 | ||
128 | new_l1_size2 = sizeof(uint64_t) * new_l1_size; | |
9a4f4c31 | 129 | new_l1_table = qemu_try_blockalign(bs->file->bs, |
de82815d KW |
130 | align_offset(new_l1_size2, 512)); |
131 | if (new_l1_table == NULL) { | |
132 | return -ENOMEM; | |
133 | } | |
134 | memset(new_l1_table, 0, align_offset(new_l1_size2, 512)); | |
135 | ||
0647d47c SH |
136 | if (s->l1_size) { |
137 | memcpy(new_l1_table, s->l1_table, s->l1_size * sizeof(uint64_t)); | |
138 | } | |
45aba42f KW |
139 | |
140 | /* write new table (align to cluster) */ | |
66f82cee | 141 | BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_ALLOC_TABLE); |
ed6ccf0f | 142 | new_l1_table_offset = qcow2_alloc_clusters(bs, new_l1_size2); |
5d757b56 | 143 | if (new_l1_table_offset < 0) { |
de82815d | 144 | qemu_vfree(new_l1_table); |
5d757b56 KW |
145 | return new_l1_table_offset; |
146 | } | |
29c1a730 KW |
147 | |
148 | ret = qcow2_cache_flush(bs, s->refcount_block_cache); | |
149 | if (ret < 0) { | |
80fa3341 | 150 | goto fail; |
29c1a730 | 151 | } |
45aba42f | 152 | |
cf93980e HR |
153 | /* the L1 position has not yet been updated, so these clusters must |
154 | * indeed be completely free */ | |
231bb267 HR |
155 | ret = qcow2_pre_write_overlap_check(bs, 0, new_l1_table_offset, |
156 | new_l1_size2); | |
cf93980e HR |
157 | if (ret < 0) { |
158 | goto fail; | |
159 | } | |
160 | ||
66f82cee | 161 | BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_WRITE_TABLE); |
45aba42f KW |
162 | for(i = 0; i < s->l1_size; i++) |
163 | new_l1_table[i] = cpu_to_be64(new_l1_table[i]); | |
d9ca2ea2 | 164 | ret = bdrv_pwrite_sync(bs->file, new_l1_table_offset, |
9a4f4c31 | 165 | new_l1_table, new_l1_size2); |
8b3b7206 | 166 | if (ret < 0) |
45aba42f KW |
167 | goto fail; |
168 | for(i = 0; i < s->l1_size; i++) | |
169 | new_l1_table[i] = be64_to_cpu(new_l1_table[i]); | |
170 | ||
171 | /* set new table */ | |
66f82cee | 172 | BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_ACTIVATE_TABLE); |
f1f7a1dd | 173 | stl_be_p(data, new_l1_size); |
e4ef9f46 | 174 | stq_be_p(data + 4, new_l1_table_offset); |
d9ca2ea2 | 175 | ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, l1_size), |
9a4f4c31 | 176 | data, sizeof(data)); |
8b3b7206 | 177 | if (ret < 0) { |
45aba42f | 178 | goto fail; |
fb8fa77c | 179 | } |
de82815d | 180 | qemu_vfree(s->l1_table); |
fda74f82 | 181 | old_l1_table_offset = s->l1_table_offset; |
45aba42f KW |
182 | s->l1_table_offset = new_l1_table_offset; |
183 | s->l1_table = new_l1_table; | |
fda74f82 | 184 | old_l1_size = s->l1_size; |
45aba42f | 185 | s->l1_size = new_l1_size; |
fda74f82 HR |
186 | qcow2_free_clusters(bs, old_l1_table_offset, old_l1_size * sizeof(uint64_t), |
187 | QCOW2_DISCARD_OTHER); | |
45aba42f KW |
188 | return 0; |
189 | fail: | |
de82815d | 190 | qemu_vfree(new_l1_table); |
6cfcb9b8 KW |
191 | qcow2_free_clusters(bs, new_l1_table_offset, new_l1_size2, |
192 | QCOW2_DISCARD_OTHER); | |
8b3b7206 | 193 | return ret; |
45aba42f KW |
194 | } |
195 | ||
45aba42f KW |
196 | /* |
197 | * l2_load | |
198 | * | |
199 | * Loads a L2 table into memory. If the table is in the cache, the cache | |
200 | * is used; otherwise the L2 table is loaded from the image file. | |
201 | * | |
202 | * Returns a pointer to the L2 table on success, or NULL if the read from | |
203 | * the image file failed. | |
204 | */ | |
205 | ||
55c17e98 KW |
206 | static int l2_load(BlockDriverState *bs, uint64_t l2_offset, |
207 | uint64_t **l2_table) | |
45aba42f | 208 | { |
ff99129a | 209 | BDRVQcow2State *s = bs->opaque; |
45aba42f | 210 | |
9be38598 EH |
211 | return qcow2_cache_get(bs, s->l2_table_cache, l2_offset, |
212 | (void **)l2_table); | |
45aba42f KW |
213 | } |
214 | ||
6583e3c7 KW |
215 | /* |
216 | * Writes one sector of the L1 table to the disk (can't update single entries | |
217 | * and we really don't want bdrv_pread to perform a read-modify-write) | |
218 | */ | |
219 | #define L1_ENTRIES_PER_SECTOR (512 / 8) | |
e23e400e | 220 | int qcow2_write_l1_entry(BlockDriverState *bs, int l1_index) |
6583e3c7 | 221 | { |
ff99129a | 222 | BDRVQcow2State *s = bs->opaque; |
a1391444 | 223 | uint64_t buf[L1_ENTRIES_PER_SECTOR] = { 0 }; |
6583e3c7 | 224 | int l1_start_index; |
f7defcb6 | 225 | int i, ret; |
6583e3c7 KW |
226 | |
227 | l1_start_index = l1_index & ~(L1_ENTRIES_PER_SECTOR - 1); | |
a1391444 HR |
228 | for (i = 0; i < L1_ENTRIES_PER_SECTOR && l1_start_index + i < s->l1_size; |
229 | i++) | |
230 | { | |
6583e3c7 KW |
231 | buf[i] = cpu_to_be64(s->l1_table[l1_start_index + i]); |
232 | } | |
233 | ||
231bb267 | 234 | ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_ACTIVE_L1, |
cf93980e HR |
235 | s->l1_table_offset + 8 * l1_start_index, sizeof(buf)); |
236 | if (ret < 0) { | |
237 | return ret; | |
238 | } | |
239 | ||
66f82cee | 240 | BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); |
d9ca2ea2 | 241 | ret = bdrv_pwrite_sync(bs->file, |
9a4f4c31 KW |
242 | s->l1_table_offset + 8 * l1_start_index, |
243 | buf, sizeof(buf)); | |
f7defcb6 KW |
244 | if (ret < 0) { |
245 | return ret; | |
6583e3c7 KW |
246 | } |
247 | ||
248 | return 0; | |
249 | } | |
250 | ||
45aba42f KW |
251 | /* |
252 | * l2_allocate | |
253 | * | |
254 | * Allocate a new l2 entry in the file. If l1_index points to an already | |
255 | * used entry in the L2 table (i.e. we are doing a copy on write for the L2 | |
256 | * table) copy the contents of the old L2 table into the newly allocated one. | |
257 | * Otherwise the new table is initialized with zeros. | |
258 | * | |
259 | */ | |
260 | ||
c46e1167 | 261 | static int l2_allocate(BlockDriverState *bs, int l1_index, uint64_t **table) |
45aba42f | 262 | { |
ff99129a | 263 | BDRVQcow2State *s = bs->opaque; |
6583e3c7 | 264 | uint64_t old_l2_offset; |
8585afd8 | 265 | uint64_t *l2_table = NULL; |
f4f0d391 | 266 | int64_t l2_offset; |
c46e1167 | 267 | int ret; |
45aba42f KW |
268 | |
269 | old_l2_offset = s->l1_table[l1_index]; | |
270 | ||
3cce16f4 KW |
271 | trace_qcow2_l2_allocate(bs, l1_index); |
272 | ||
45aba42f KW |
273 | /* allocate a new l2 entry */ |
274 | ||
ed6ccf0f | 275 | l2_offset = qcow2_alloc_clusters(bs, s->l2_size * sizeof(uint64_t)); |
5d757b56 | 276 | if (l2_offset < 0) { |
be0b742e HR |
277 | ret = l2_offset; |
278 | goto fail; | |
5d757b56 | 279 | } |
29c1a730 KW |
280 | |
281 | ret = qcow2_cache_flush(bs, s->refcount_block_cache); | |
282 | if (ret < 0) { | |
283 | goto fail; | |
284 | } | |
45aba42f | 285 | |
45aba42f KW |
286 | /* allocate a new entry in the l2 cache */ |
287 | ||
3cce16f4 | 288 | trace_qcow2_l2_allocate_get_empty(bs, l1_index); |
29c1a730 KW |
289 | ret = qcow2_cache_get_empty(bs, s->l2_table_cache, l2_offset, (void**) table); |
290 | if (ret < 0) { | |
be0b742e | 291 | goto fail; |
29c1a730 KW |
292 | } |
293 | ||
294 | l2_table = *table; | |
45aba42f | 295 | |
8e37f681 | 296 | if ((old_l2_offset & L1E_OFFSET_MASK) == 0) { |
45aba42f KW |
297 | /* if there was no old l2 table, clear the new table */ |
298 | memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); | |
299 | } else { | |
29c1a730 KW |
300 | uint64_t* old_table; |
301 | ||
45aba42f | 302 | /* if there was an old l2 table, read it from the disk */ |
66f82cee | 303 | BLKDBG_EVENT(bs->file, BLKDBG_L2_ALLOC_COW_READ); |
8e37f681 KW |
304 | ret = qcow2_cache_get(bs, s->l2_table_cache, |
305 | old_l2_offset & L1E_OFFSET_MASK, | |
29c1a730 KW |
306 | (void**) &old_table); |
307 | if (ret < 0) { | |
308 | goto fail; | |
309 | } | |
310 | ||
311 | memcpy(l2_table, old_table, s->cluster_size); | |
312 | ||
a3f1afb4 | 313 | qcow2_cache_put(bs, s->l2_table_cache, (void **) &old_table); |
45aba42f | 314 | } |
29c1a730 | 315 | |
45aba42f | 316 | /* write the l2 table to the file */ |
66f82cee | 317 | BLKDBG_EVENT(bs->file, BLKDBG_L2_ALLOC_WRITE); |
29c1a730 | 318 | |
3cce16f4 | 319 | trace_qcow2_l2_allocate_write_l2(bs, l1_index); |
72e80b89 | 320 | qcow2_cache_entry_mark_dirty(bs, s->l2_table_cache, l2_table); |
29c1a730 | 321 | ret = qcow2_cache_flush(bs, s->l2_table_cache); |
c46e1167 | 322 | if (ret < 0) { |
175e1152 KW |
323 | goto fail; |
324 | } | |
325 | ||
326 | /* update the L1 entry */ | |
3cce16f4 | 327 | trace_qcow2_l2_allocate_write_l1(bs, l1_index); |
175e1152 | 328 | s->l1_table[l1_index] = l2_offset | QCOW_OFLAG_COPIED; |
e23e400e | 329 | ret = qcow2_write_l1_entry(bs, l1_index); |
175e1152 KW |
330 | if (ret < 0) { |
331 | goto fail; | |
c46e1167 | 332 | } |
45aba42f | 333 | |
c46e1167 | 334 | *table = l2_table; |
3cce16f4 | 335 | trace_qcow2_l2_allocate_done(bs, l1_index, 0); |
c46e1167 | 336 | return 0; |
175e1152 KW |
337 | |
338 | fail: | |
3cce16f4 | 339 | trace_qcow2_l2_allocate_done(bs, l1_index, ret); |
8585afd8 HR |
340 | if (l2_table != NULL) { |
341 | qcow2_cache_put(bs, s->l2_table_cache, (void**) table); | |
342 | } | |
68dba0bf | 343 | s->l1_table[l1_index] = old_l2_offset; |
e3b21ef9 HR |
344 | if (l2_offset > 0) { |
345 | qcow2_free_clusters(bs, l2_offset, s->l2_size * sizeof(uint64_t), | |
346 | QCOW2_DISCARD_ALWAYS); | |
347 | } | |
175e1152 | 348 | return ret; |
45aba42f KW |
349 | } |
350 | ||
2bfcc4a0 KW |
351 | /* |
352 | * Checks how many clusters in a given L2 table are contiguous in the image | |
353 | * file. As soon as one of the flags in the bitmask stop_flags changes compared | |
354 | * to the first cluster, the search is stopped and the cluster is not counted | |
355 | * as contiguous. (This allows it, for example, to stop at the first compressed | |
356 | * cluster which may require a different handling) | |
357 | */ | |
b6d36def | 358 | static int count_contiguous_clusters(int nb_clusters, int cluster_size, |
61653008 | 359 | uint64_t *l2_table, uint64_t stop_flags) |
45aba42f KW |
360 | { |
361 | int i; | |
3ef95218 | 362 | QCow2ClusterType first_cluster_type; |
78a52ad5 | 363 | uint64_t mask = stop_flags | L2E_OFFSET_MASK | QCOW_OFLAG_COMPRESSED; |
15684a47 HR |
364 | uint64_t first_entry = be64_to_cpu(l2_table[0]); |
365 | uint64_t offset = first_entry & mask; | |
45aba42f | 366 | |
564a6b69 | 367 | if (!offset) { |
45aba42f | 368 | return 0; |
564a6b69 | 369 | } |
45aba42f | 370 | |
564a6b69 HR |
371 | /* must be allocated */ |
372 | first_cluster_type = qcow2_get_cluster_type(first_entry); | |
373 | assert(first_cluster_type == QCOW2_CLUSTER_NORMAL || | |
fdfab37d | 374 | first_cluster_type == QCOW2_CLUSTER_ZERO_ALLOC); |
15684a47 | 375 | |
61653008 | 376 | for (i = 0; i < nb_clusters; i++) { |
2bfcc4a0 KW |
377 | uint64_t l2_entry = be64_to_cpu(l2_table[i]) & mask; |
378 | if (offset + (uint64_t) i * cluster_size != l2_entry) { | |
45aba42f | 379 | break; |
2bfcc4a0 KW |
380 | } |
381 | } | |
45aba42f | 382 | |
61653008 | 383 | return i; |
45aba42f KW |
384 | } |
385 | ||
4341df8a EB |
386 | /* |
387 | * Checks how many consecutive unallocated clusters in a given L2 | |
388 | * table have the same cluster type. | |
389 | */ | |
390 | static int count_contiguous_clusters_unallocated(int nb_clusters, | |
391 | uint64_t *l2_table, | |
3ef95218 | 392 | QCow2ClusterType wanted_type) |
45aba42f | 393 | { |
2bfcc4a0 KW |
394 | int i; |
395 | ||
fdfab37d | 396 | assert(wanted_type == QCOW2_CLUSTER_ZERO_PLAIN || |
4341df8a | 397 | wanted_type == QCOW2_CLUSTER_UNALLOCATED); |
2bfcc4a0 | 398 | for (i = 0; i < nb_clusters; i++) { |
4341df8a | 399 | uint64_t entry = be64_to_cpu(l2_table[i]); |
3ef95218 | 400 | QCow2ClusterType type = qcow2_get_cluster_type(entry); |
45aba42f | 401 | |
fdfab37d | 402 | if (type != wanted_type) { |
2bfcc4a0 KW |
403 | break; |
404 | } | |
405 | } | |
45aba42f KW |
406 | |
407 | return i; | |
408 | } | |
409 | ||
672f0f2c AG |
410 | static int coroutine_fn do_perform_cow_read(BlockDriverState *bs, |
411 | uint64_t src_cluster_offset, | |
412 | unsigned offset_in_cluster, | |
86b862c4 | 413 | QEMUIOVector *qiov) |
45aba42f | 414 | { |
aaa4d20b | 415 | int ret; |
1b9f1491 | 416 | |
86b862c4 | 417 | if (qiov->size == 0) { |
99450c6f AG |
418 | return 0; |
419 | } | |
420 | ||
66f82cee | 421 | BLKDBG_EVENT(bs->file, BLKDBG_COW_READ); |
aef4acb6 | 422 | |
dba28555 | 423 | if (!bs->drv) { |
672f0f2c | 424 | return -ENOMEDIUM; |
dba28555 HR |
425 | } |
426 | ||
aef4acb6 SH |
427 | /* Call .bdrv_co_readv() directly instead of using the public block-layer |
428 | * interface. This avoids double I/O throttling and request tracking, | |
429 | * which can lead to deadlock when block layer copy-on-read is enabled. | |
430 | */ | |
aaa4d20b | 431 | ret = bs->drv->bdrv_co_preadv(bs, src_cluster_offset + offset_in_cluster, |
86b862c4 | 432 | qiov->size, qiov, 0); |
1b9f1491 | 433 | if (ret < 0) { |
672f0f2c | 434 | return ret; |
1b9f1491 KW |
435 | } |
436 | ||
672f0f2c AG |
437 | return 0; |
438 | } | |
439 | ||
440 | static bool coroutine_fn do_perform_cow_encrypt(BlockDriverState *bs, | |
441 | uint64_t src_cluster_offset, | |
4652b8f3 | 442 | uint64_t cluster_offset, |
672f0f2c AG |
443 | unsigned offset_in_cluster, |
444 | uint8_t *buffer, | |
445 | unsigned bytes) | |
446 | { | |
447 | if (bytes && bs->encrypted) { | |
448 | BDRVQcow2State *s = bs->opaque; | |
4609742a | 449 | int64_t offset = (s->crypt_physical_offset ? |
4652b8f3 | 450 | (cluster_offset + offset_in_cluster) : |
4609742a | 451 | (src_cluster_offset + offset_in_cluster)); |
aaa4d20b KW |
452 | assert((offset_in_cluster & ~BDRV_SECTOR_MASK) == 0); |
453 | assert((bytes & ~BDRV_SECTOR_MASK) == 0); | |
b25b387f | 454 | assert(s->crypto); |
4609742a | 455 | if (qcrypto_block_encrypt(s->crypto, offset, buffer, bytes, NULL) < 0) { |
672f0f2c | 456 | return false; |
f6fa64f6 | 457 | } |
45aba42f | 458 | } |
672f0f2c AG |
459 | return true; |
460 | } | |
461 | ||
462 | static int coroutine_fn do_perform_cow_write(BlockDriverState *bs, | |
463 | uint64_t cluster_offset, | |
464 | unsigned offset_in_cluster, | |
86b862c4 | 465 | QEMUIOVector *qiov) |
672f0f2c | 466 | { |
672f0f2c AG |
467 | int ret; |
468 | ||
86b862c4 | 469 | if (qiov->size == 0) { |
672f0f2c AG |
470 | return 0; |
471 | } | |
472 | ||
231bb267 | 473 | ret = qcow2_pre_write_overlap_check(bs, 0, |
86b862c4 | 474 | cluster_offset + offset_in_cluster, qiov->size); |
cf93980e | 475 | if (ret < 0) { |
672f0f2c | 476 | return ret; |
cf93980e HR |
477 | } |
478 | ||
66f82cee | 479 | BLKDBG_EVENT(bs->file, BLKDBG_COW_WRITE); |
a03ef88f | 480 | ret = bdrv_co_pwritev(bs->file, cluster_offset + offset_in_cluster, |
86b862c4 | 481 | qiov->size, qiov, 0); |
1b9f1491 | 482 | if (ret < 0) { |
672f0f2c | 483 | return ret; |
1b9f1491 KW |
484 | } |
485 | ||
672f0f2c | 486 | return 0; |
45aba42f KW |
487 | } |
488 | ||
489 | ||
490 | /* | |
491 | * get_cluster_offset | |
492 | * | |
ecfe1863 KW |
493 | * For a given offset of the virtual disk, find the cluster type and offset in |
494 | * the qcow2 file. The offset is stored in *cluster_offset. | |
45aba42f | 495 | * |
ecfe1863 KW |
496 | * On entry, *bytes is the maximum number of contiguous bytes starting at |
497 | * offset that we are interested in. | |
45aba42f | 498 | * |
ecfe1863 KW |
499 | * On exit, *bytes is the number of bytes starting at offset that have the same |
500 | * cluster type and (if applicable) are stored contiguously in the image file. | |
501 | * Compressed clusters are always returned one by one. | |
45aba42f | 502 | * |
68d000a3 KW |
503 | * Returns the cluster type (QCOW2_CLUSTER_*) on success, -errno in error |
504 | * cases. | |
45aba42f | 505 | */ |
1c46efaa | 506 | int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset, |
ecfe1863 | 507 | unsigned int *bytes, uint64_t *cluster_offset) |
45aba42f | 508 | { |
ff99129a | 509 | BDRVQcow2State *s = bs->opaque; |
2cf7cfa1 KW |
510 | unsigned int l2_index; |
511 | uint64_t l1_index, l2_offset, *l2_table; | |
45aba42f | 512 | int l1_bits, c; |
c834cba9 HR |
513 | unsigned int offset_in_cluster; |
514 | uint64_t bytes_available, bytes_needed, nb_clusters; | |
3ef95218 | 515 | QCow2ClusterType type; |
55c17e98 | 516 | int ret; |
45aba42f | 517 | |
b2f65d6b | 518 | offset_in_cluster = offset_into_cluster(s, offset); |
ecfe1863 | 519 | bytes_needed = (uint64_t) *bytes + offset_in_cluster; |
45aba42f | 520 | |
b2f65d6b | 521 | l1_bits = s->l2_bits + s->cluster_bits; |
45aba42f | 522 | |
b2f65d6b KW |
523 | /* compute how many bytes there are between the start of the cluster |
524 | * containing offset and the end of the l1 entry */ | |
525 | bytes_available = (1ULL << l1_bits) - (offset & ((1ULL << l1_bits) - 1)) | |
526 | + offset_in_cluster; | |
45aba42f | 527 | |
b2f65d6b KW |
528 | if (bytes_needed > bytes_available) { |
529 | bytes_needed = bytes_available; | |
45aba42f KW |
530 | } |
531 | ||
1c46efaa | 532 | *cluster_offset = 0; |
45aba42f | 533 | |
b6af0975 | 534 | /* seek to the l2 offset in the l1 table */ |
45aba42f KW |
535 | |
536 | l1_index = offset >> l1_bits; | |
68d000a3 | 537 | if (l1_index >= s->l1_size) { |
3ef95218 | 538 | type = QCOW2_CLUSTER_UNALLOCATED; |
45aba42f | 539 | goto out; |
68d000a3 | 540 | } |
45aba42f | 541 | |
68d000a3 KW |
542 | l2_offset = s->l1_table[l1_index] & L1E_OFFSET_MASK; |
543 | if (!l2_offset) { | |
3ef95218 | 544 | type = QCOW2_CLUSTER_UNALLOCATED; |
45aba42f | 545 | goto out; |
68d000a3 | 546 | } |
45aba42f | 547 | |
a97c67ee HR |
548 | if (offset_into_cluster(s, l2_offset)) { |
549 | qcow2_signal_corruption(bs, true, -1, -1, "L2 table offset %#" PRIx64 | |
550 | " unaligned (L1 index: %#" PRIx64 ")", | |
551 | l2_offset, l1_index); | |
552 | return -EIO; | |
553 | } | |
554 | ||
45aba42f KW |
555 | /* load the l2 table in memory */ |
556 | ||
55c17e98 KW |
557 | ret = l2_load(bs, l2_offset, &l2_table); |
558 | if (ret < 0) { | |
559 | return ret; | |
1c46efaa | 560 | } |
45aba42f KW |
561 | |
562 | /* find the cluster offset for the given disk offset */ | |
563 | ||
24990c5b | 564 | l2_index = offset_to_l2_index(s, offset); |
1c46efaa | 565 | *cluster_offset = be64_to_cpu(l2_table[l2_index]); |
b6d36def | 566 | |
b2f65d6b | 567 | nb_clusters = size_to_clusters(s, bytes_needed); |
c834cba9 HR |
568 | /* bytes_needed <= *bytes + offset_in_cluster, both of which are unsigned |
569 | * integers; the minimum cluster size is 512, so this assertion is always | |
570 | * true */ | |
571 | assert(nb_clusters <= INT_MAX); | |
45aba42f | 572 | |
3ef95218 | 573 | type = qcow2_get_cluster_type(*cluster_offset); |
fdfab37d EB |
574 | if (s->qcow_version < 3 && (type == QCOW2_CLUSTER_ZERO_PLAIN || |
575 | type == QCOW2_CLUSTER_ZERO_ALLOC)) { | |
576 | qcow2_signal_corruption(bs, true, -1, -1, "Zero cluster entry found" | |
577 | " in pre-v3 image (L2 offset: %#" PRIx64 | |
578 | ", L2 index: %#x)", l2_offset, l2_index); | |
579 | ret = -EIO; | |
580 | goto fail; | |
581 | } | |
3ef95218 | 582 | switch (type) { |
68d000a3 KW |
583 | case QCOW2_CLUSTER_COMPRESSED: |
584 | /* Compressed clusters can only be processed one by one */ | |
585 | c = 1; | |
586 | *cluster_offset &= L2E_COMPRESSED_OFFSET_SIZE_MASK; | |
587 | break; | |
fdfab37d | 588 | case QCOW2_CLUSTER_ZERO_PLAIN: |
68d000a3 | 589 | case QCOW2_CLUSTER_UNALLOCATED: |
45aba42f | 590 | /* how many empty clusters ? */ |
4341df8a | 591 | c = count_contiguous_clusters_unallocated(nb_clusters, |
fdfab37d | 592 | &l2_table[l2_index], type); |
68d000a3 KW |
593 | *cluster_offset = 0; |
594 | break; | |
fdfab37d | 595 | case QCOW2_CLUSTER_ZERO_ALLOC: |
68d000a3 | 596 | case QCOW2_CLUSTER_NORMAL: |
45aba42f KW |
597 | /* how many allocated clusters ? */ |
598 | c = count_contiguous_clusters(nb_clusters, s->cluster_size, | |
fdfab37d | 599 | &l2_table[l2_index], QCOW_OFLAG_ZERO); |
68d000a3 | 600 | *cluster_offset &= L2E_OFFSET_MASK; |
a97c67ee | 601 | if (offset_into_cluster(s, *cluster_offset)) { |
fdfab37d EB |
602 | qcow2_signal_corruption(bs, true, -1, -1, |
603 | "Cluster allocation offset %#" | |
a97c67ee HR |
604 | PRIx64 " unaligned (L2 offset: %#" PRIx64 |
605 | ", L2 index: %#x)", *cluster_offset, | |
606 | l2_offset, l2_index); | |
607 | ret = -EIO; | |
608 | goto fail; | |
609 | } | |
68d000a3 | 610 | break; |
1417d7e4 KW |
611 | default: |
612 | abort(); | |
45aba42f KW |
613 | } |
614 | ||
29c1a730 KW |
615 | qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); |
616 | ||
c834cba9 | 617 | bytes_available = (int64_t)c * s->cluster_size; |
68d000a3 | 618 | |
45aba42f | 619 | out: |
b2f65d6b KW |
620 | if (bytes_available > bytes_needed) { |
621 | bytes_available = bytes_needed; | |
622 | } | |
45aba42f | 623 | |
c834cba9 HR |
624 | /* bytes_available <= bytes_needed <= *bytes + offset_in_cluster; |
625 | * subtracting offset_in_cluster will therefore definitely yield something | |
626 | * not exceeding UINT_MAX */ | |
627 | assert(bytes_available - offset_in_cluster <= UINT_MAX); | |
ecfe1863 | 628 | *bytes = bytes_available - offset_in_cluster; |
45aba42f | 629 | |
3ef95218 | 630 | return type; |
a97c67ee HR |
631 | |
632 | fail: | |
633 | qcow2_cache_put(bs, s->l2_table_cache, (void **)&l2_table); | |
634 | return ret; | |
45aba42f KW |
635 | } |
636 | ||
637 | /* | |
638 | * get_cluster_table | |
639 | * | |
640 | * for a given disk offset, load (and allocate if needed) | |
641 | * the l2 table. | |
642 | * | |
643 | * the l2 table offset in the qcow2 file and the cluster index | |
644 | * in the l2 table are given to the caller. | |
645 | * | |
1e3e8f1a | 646 | * Returns 0 on success, -errno in failure case |
45aba42f | 647 | */ |
45aba42f KW |
648 | static int get_cluster_table(BlockDriverState *bs, uint64_t offset, |
649 | uint64_t **new_l2_table, | |
45aba42f KW |
650 | int *new_l2_index) |
651 | { | |
ff99129a | 652 | BDRVQcow2State *s = bs->opaque; |
2cf7cfa1 KW |
653 | unsigned int l2_index; |
654 | uint64_t l1_index, l2_offset; | |
c46e1167 | 655 | uint64_t *l2_table = NULL; |
80ee15a6 | 656 | int ret; |
45aba42f | 657 | |
b6af0975 | 658 | /* seek to the l2 offset in the l1 table */ |
45aba42f KW |
659 | |
660 | l1_index = offset >> (s->l2_bits + s->cluster_bits); | |
661 | if (l1_index >= s->l1_size) { | |
72893756 | 662 | ret = qcow2_grow_l1_table(bs, l1_index + 1, false); |
1e3e8f1a KW |
663 | if (ret < 0) { |
664 | return ret; | |
665 | } | |
45aba42f | 666 | } |
8e37f681 | 667 | |
2cf7cfa1 | 668 | assert(l1_index < s->l1_size); |
8e37f681 | 669 | l2_offset = s->l1_table[l1_index] & L1E_OFFSET_MASK; |
a97c67ee HR |
670 | if (offset_into_cluster(s, l2_offset)) { |
671 | qcow2_signal_corruption(bs, true, -1, -1, "L2 table offset %#" PRIx64 | |
672 | " unaligned (L1 index: %#" PRIx64 ")", | |
673 | l2_offset, l1_index); | |
674 | return -EIO; | |
675 | } | |
45aba42f KW |
676 | |
677 | /* seek the l2 table of the given l2 offset */ | |
678 | ||
8e37f681 | 679 | if (s->l1_table[l1_index] & QCOW_OFLAG_COPIED) { |
45aba42f | 680 | /* load the l2 table in memory */ |
55c17e98 KW |
681 | ret = l2_load(bs, l2_offset, &l2_table); |
682 | if (ret < 0) { | |
683 | return ret; | |
1e3e8f1a | 684 | } |
45aba42f | 685 | } else { |
16fde5f2 | 686 | /* First allocate a new L2 table (and do COW if needed) */ |
c46e1167 KW |
687 | ret = l2_allocate(bs, l1_index, &l2_table); |
688 | if (ret < 0) { | |
689 | return ret; | |
1e3e8f1a | 690 | } |
16fde5f2 KW |
691 | |
692 | /* Then decrease the refcount of the old table */ | |
693 | if (l2_offset) { | |
6cfcb9b8 KW |
694 | qcow2_free_clusters(bs, l2_offset, s->l2_size * sizeof(uint64_t), |
695 | QCOW2_DISCARD_OTHER); | |
16fde5f2 | 696 | } |
45aba42f KW |
697 | } |
698 | ||
699 | /* find the cluster offset for the given disk offset */ | |
700 | ||
24990c5b | 701 | l2_index = offset_to_l2_index(s, offset); |
45aba42f KW |
702 | |
703 | *new_l2_table = l2_table; | |
45aba42f KW |
704 | *new_l2_index = l2_index; |
705 | ||
1e3e8f1a | 706 | return 0; |
45aba42f KW |
707 | } |
708 | ||
709 | /* | |
710 | * alloc_compressed_cluster_offset | |
711 | * | |
712 | * For a given offset of the disk image, return cluster offset in | |
713 | * qcow2 file. | |
714 | * | |
715 | * If the offset is not found, allocate a new compressed cluster. | |
716 | * | |
717 | * Return the cluster offset if successful, | |
718 | * Return 0, otherwise. | |
719 | * | |
720 | */ | |
721 | ||
ed6ccf0f KW |
722 | uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs, |
723 | uint64_t offset, | |
724 | int compressed_size) | |
45aba42f | 725 | { |
ff99129a | 726 | BDRVQcow2State *s = bs->opaque; |
45aba42f | 727 | int l2_index, ret; |
3948d1d4 | 728 | uint64_t *l2_table; |
f4f0d391 | 729 | int64_t cluster_offset; |
45aba42f KW |
730 | int nb_csectors; |
731 | ||
3948d1d4 | 732 | ret = get_cluster_table(bs, offset, &l2_table, &l2_index); |
1e3e8f1a | 733 | if (ret < 0) { |
45aba42f | 734 | return 0; |
1e3e8f1a | 735 | } |
45aba42f | 736 | |
b0b6862e KW |
737 | /* Compression can't overwrite anything. Fail if the cluster was already |
738 | * allocated. */ | |
45aba42f | 739 | cluster_offset = be64_to_cpu(l2_table[l2_index]); |
b0b6862e | 740 | if (cluster_offset & L2E_OFFSET_MASK) { |
8f1efd00 KW |
741 | qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); |
742 | return 0; | |
743 | } | |
45aba42f | 744 | |
ed6ccf0f | 745 | cluster_offset = qcow2_alloc_bytes(bs, compressed_size); |
5d757b56 | 746 | if (cluster_offset < 0) { |
29c1a730 | 747 | qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); |
5d757b56 KW |
748 | return 0; |
749 | } | |
750 | ||
45aba42f KW |
751 | nb_csectors = ((cluster_offset + compressed_size - 1) >> 9) - |
752 | (cluster_offset >> 9); | |
753 | ||
754 | cluster_offset |= QCOW_OFLAG_COMPRESSED | | |
755 | ((uint64_t)nb_csectors << s->csize_shift); | |
756 | ||
757 | /* update L2 table */ | |
758 | ||
759 | /* compressed clusters never have the copied flag */ | |
760 | ||
66f82cee | 761 | BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE_COMPRESSED); |
72e80b89 | 762 | qcow2_cache_entry_mark_dirty(bs, s->l2_table_cache, l2_table); |
45aba42f | 763 | l2_table[l2_index] = cpu_to_be64(cluster_offset); |
a3f1afb4 | 764 | qcow2_cache_put(bs, s->l2_table_cache, (void **) &l2_table); |
4c1612d9 | 765 | |
29c1a730 | 766 | return cluster_offset; |
4c1612d9 KW |
767 | } |
768 | ||
99450c6f | 769 | static int perform_cow(BlockDriverState *bs, QCowL2Meta *m) |
593fb83c | 770 | { |
ff99129a | 771 | BDRVQcow2State *s = bs->opaque; |
99450c6f AG |
772 | Qcow2COWRegion *start = &m->cow_start; |
773 | Qcow2COWRegion *end = &m->cow_end; | |
672f0f2c | 774 | unsigned buffer_size; |
b3cf1c7c AG |
775 | unsigned data_bytes = end->offset - (start->offset + start->nb_bytes); |
776 | bool merge_reads; | |
672f0f2c | 777 | uint8_t *start_buffer, *end_buffer; |
86b862c4 | 778 | QEMUIOVector qiov; |
593fb83c KW |
779 | int ret; |
780 | ||
672f0f2c | 781 | assert(start->nb_bytes <= UINT_MAX - end->nb_bytes); |
b3cf1c7c AG |
782 | assert(start->nb_bytes + end->nb_bytes <= UINT_MAX - data_bytes); |
783 | assert(start->offset + start->nb_bytes <= end->offset); | |
ee22a9d8 | 784 | assert(!m->data_qiov || m->data_qiov->size == data_bytes); |
672f0f2c | 785 | |
99450c6f | 786 | if (start->nb_bytes == 0 && end->nb_bytes == 0) { |
593fb83c KW |
787 | return 0; |
788 | } | |
789 | ||
b3cf1c7c AG |
790 | /* If we have to read both the start and end COW regions and the |
791 | * middle region is not too large then perform just one read | |
792 | * operation */ | |
793 | merge_reads = start->nb_bytes && end->nb_bytes && data_bytes <= 16384; | |
794 | if (merge_reads) { | |
795 | buffer_size = start->nb_bytes + data_bytes + end->nb_bytes; | |
796 | } else { | |
797 | /* If we have to do two reads, add some padding in the middle | |
798 | * if necessary to make sure that the end region is optimally | |
799 | * aligned. */ | |
800 | size_t align = bdrv_opt_mem_align(bs); | |
801 | assert(align > 0 && align <= UINT_MAX); | |
802 | assert(QEMU_ALIGN_UP(start->nb_bytes, align) <= | |
803 | UINT_MAX - end->nb_bytes); | |
804 | buffer_size = QEMU_ALIGN_UP(start->nb_bytes, align) + end->nb_bytes; | |
805 | } | |
806 | ||
807 | /* Reserve a buffer large enough to store all the data that we're | |
808 | * going to read */ | |
672f0f2c AG |
809 | start_buffer = qemu_try_blockalign(bs, buffer_size); |
810 | if (start_buffer == NULL) { | |
811 | return -ENOMEM; | |
812 | } | |
813 | /* The part of the buffer where the end region is located */ | |
814 | end_buffer = start_buffer + buffer_size - end->nb_bytes; | |
815 | ||
ee22a9d8 | 816 | qemu_iovec_init(&qiov, 2 + (m->data_qiov ? m->data_qiov->niov : 0)); |
86b862c4 | 817 | |
593fb83c | 818 | qemu_co_mutex_unlock(&s->lock); |
b3cf1c7c AG |
819 | /* First we read the existing data from both COW regions. We |
820 | * either read the whole region in one go, or the start and end | |
821 | * regions separately. */ | |
822 | if (merge_reads) { | |
86b862c4 AG |
823 | qemu_iovec_add(&qiov, start_buffer, buffer_size); |
824 | ret = do_perform_cow_read(bs, m->offset, start->offset, &qiov); | |
b3cf1c7c | 825 | } else { |
86b862c4 AG |
826 | qemu_iovec_add(&qiov, start_buffer, start->nb_bytes); |
827 | ret = do_perform_cow_read(bs, m->offset, start->offset, &qiov); | |
b3cf1c7c AG |
828 | if (ret < 0) { |
829 | goto fail; | |
830 | } | |
672f0f2c | 831 | |
86b862c4 AG |
832 | qemu_iovec_reset(&qiov); |
833 | qemu_iovec_add(&qiov, end_buffer, end->nb_bytes); | |
834 | ret = do_perform_cow_read(bs, m->offset, end->offset, &qiov); | |
b3cf1c7c | 835 | } |
593fb83c | 836 | if (ret < 0) { |
99450c6f | 837 | goto fail; |
593fb83c KW |
838 | } |
839 | ||
672f0f2c AG |
840 | /* Encrypt the data if necessary before writing it */ |
841 | if (bs->encrypted) { | |
4652b8f3 DB |
842 | if (!do_perform_cow_encrypt(bs, m->offset, m->alloc_offset, |
843 | start->offset, start_buffer, | |
844 | start->nb_bytes) || | |
845 | !do_perform_cow_encrypt(bs, m->offset, m->alloc_offset, | |
846 | end->offset, end_buffer, end->nb_bytes)) { | |
672f0f2c AG |
847 | ret = -EIO; |
848 | goto fail; | |
849 | } | |
850 | } | |
851 | ||
ee22a9d8 AG |
852 | /* And now we can write everything. If we have the guest data we |
853 | * can write everything in one single operation */ | |
854 | if (m->data_qiov) { | |
855 | qemu_iovec_reset(&qiov); | |
856 | if (start->nb_bytes) { | |
857 | qemu_iovec_add(&qiov, start_buffer, start->nb_bytes); | |
858 | } | |
859 | qemu_iovec_concat(&qiov, m->data_qiov, 0, data_bytes); | |
860 | if (end->nb_bytes) { | |
861 | qemu_iovec_add(&qiov, end_buffer, end->nb_bytes); | |
862 | } | |
863 | /* NOTE: we have a write_aio blkdebug event here followed by | |
864 | * a cow_write one in do_perform_cow_write(), but there's only | |
865 | * one single I/O operation */ | |
866 | BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); | |
867 | ret = do_perform_cow_write(bs, m->alloc_offset, start->offset, &qiov); | |
868 | } else { | |
869 | /* If there's no guest data then write both COW regions separately */ | |
870 | qemu_iovec_reset(&qiov); | |
871 | qemu_iovec_add(&qiov, start_buffer, start->nb_bytes); | |
872 | ret = do_perform_cow_write(bs, m->alloc_offset, start->offset, &qiov); | |
873 | if (ret < 0) { | |
874 | goto fail; | |
875 | } | |
876 | ||
877 | qemu_iovec_reset(&qiov); | |
878 | qemu_iovec_add(&qiov, end_buffer, end->nb_bytes); | |
879 | ret = do_perform_cow_write(bs, m->alloc_offset, end->offset, &qiov); | |
672f0f2c | 880 | } |
99450c6f AG |
881 | |
882 | fail: | |
883 | qemu_co_mutex_lock(&s->lock); | |
884 | ||
593fb83c KW |
885 | /* |
886 | * Before we update the L2 table to actually point to the new cluster, we | |
887 | * need to be sure that the refcounts have been increased and COW was | |
888 | * handled. | |
889 | */ | |
99450c6f AG |
890 | if (ret == 0) { |
891 | qcow2_cache_depends_on_flush(s->l2_table_cache); | |
892 | } | |
593fb83c | 893 | |
672f0f2c | 894 | qemu_vfree(start_buffer); |
86b862c4 | 895 | qemu_iovec_destroy(&qiov); |
99450c6f | 896 | return ret; |
593fb83c KW |
897 | } |
898 | ||
148da7ea | 899 | int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m) |
45aba42f | 900 | { |
ff99129a | 901 | BDRVQcow2State *s = bs->opaque; |
45aba42f | 902 | int i, j = 0, l2_index, ret; |
593fb83c | 903 | uint64_t *old_cluster, *l2_table; |
250196f1 | 904 | uint64_t cluster_offset = m->alloc_offset; |
45aba42f | 905 | |
3cce16f4 | 906 | trace_qcow2_cluster_link_l2(qemu_coroutine_self(), m->nb_clusters); |
f50f88b9 | 907 | assert(m->nb_clusters > 0); |
45aba42f | 908 | |
5839e53b | 909 | old_cluster = g_try_new(uint64_t, m->nb_clusters); |
de82815d KW |
910 | if (old_cluster == NULL) { |
911 | ret = -ENOMEM; | |
912 | goto err; | |
913 | } | |
45aba42f KW |
914 | |
915 | /* copy content of unmodified sectors */ | |
99450c6f | 916 | ret = perform_cow(bs, m); |
593fb83c KW |
917 | if (ret < 0) { |
918 | goto err; | |
29c1a730 KW |
919 | } |
920 | ||
593fb83c | 921 | /* Update L2 table. */ |
74c4510a | 922 | if (s->use_lazy_refcounts) { |
280d3735 KW |
923 | qcow2_mark_dirty(bs); |
924 | } | |
bfe8043e SH |
925 | if (qcow2_need_accurate_refcounts(s)) { |
926 | qcow2_cache_set_dependency(bs, s->l2_table_cache, | |
927 | s->refcount_block_cache); | |
928 | } | |
280d3735 | 929 | |
3948d1d4 | 930 | ret = get_cluster_table(bs, m->offset, &l2_table, &l2_index); |
1e3e8f1a | 931 | if (ret < 0) { |
45aba42f | 932 | goto err; |
1e3e8f1a | 933 | } |
72e80b89 | 934 | qcow2_cache_entry_mark_dirty(bs, s->l2_table_cache, l2_table); |
45aba42f | 935 | |
c01dbccb | 936 | assert(l2_index + m->nb_clusters <= s->l2_size); |
45aba42f KW |
937 | for (i = 0; i < m->nb_clusters; i++) { |
938 | /* if two concurrent writes happen to the same unallocated cluster | |
aaa4d20b KW |
939 | * each write allocates separate cluster and writes data concurrently. |
940 | * The first one to complete updates l2 table with pointer to its | |
941 | * cluster the second one has to do RMW (which is done above by | |
942 | * perform_cow()), update l2 table with its cluster pointer and free | |
943 | * old cluster. This is what this loop does */ | |
944 | if (l2_table[l2_index + i] != 0) { | |
45aba42f | 945 | old_cluster[j++] = l2_table[l2_index + i]; |
aaa4d20b | 946 | } |
45aba42f KW |
947 | |
948 | l2_table[l2_index + i] = cpu_to_be64((cluster_offset + | |
949 | (i << s->cluster_bits)) | QCOW_OFLAG_COPIED); | |
950 | } | |
951 | ||
9f8e668e | 952 | |
a3f1afb4 | 953 | qcow2_cache_put(bs, s->l2_table_cache, (void **) &l2_table); |
45aba42f | 954 | |
7ec5e6a4 KW |
955 | /* |
956 | * If this was a COW, we need to decrease the refcount of the old cluster. | |
6cfcb9b8 KW |
957 | * |
958 | * Don't discard clusters that reach a refcount of 0 (e.g. compressed | |
959 | * clusters), the next write will reuse them anyway. | |
7ec5e6a4 | 960 | */ |
564a6b69 | 961 | if (!m->keep_old_clusters && j != 0) { |
7ec5e6a4 | 962 | for (i = 0; i < j; i++) { |
6cfcb9b8 KW |
963 | qcow2_free_any_clusters(bs, be64_to_cpu(old_cluster[i]), 1, |
964 | QCOW2_DISCARD_NEVER); | |
7ec5e6a4 KW |
965 | } |
966 | } | |
45aba42f KW |
967 | |
968 | ret = 0; | |
969 | err: | |
7267c094 | 970 | g_free(old_cluster); |
45aba42f KW |
971 | return ret; |
972 | } | |
973 | ||
bf319ece KW |
974 | /* |
975 | * Returns the number of contiguous clusters that can be used for an allocating | |
976 | * write, but require COW to be performed (this includes yet unallocated space, | |
977 | * which must copy from the backing file) | |
978 | */ | |
ff99129a | 979 | static int count_cow_clusters(BDRVQcow2State *s, int nb_clusters, |
bf319ece KW |
980 | uint64_t *l2_table, int l2_index) |
981 | { | |
143550a8 | 982 | int i; |
bf319ece | 983 | |
143550a8 KW |
984 | for (i = 0; i < nb_clusters; i++) { |
985 | uint64_t l2_entry = be64_to_cpu(l2_table[l2_index + i]); | |
3ef95218 | 986 | QCow2ClusterType cluster_type = qcow2_get_cluster_type(l2_entry); |
143550a8 KW |
987 | |
988 | switch(cluster_type) { | |
989 | case QCOW2_CLUSTER_NORMAL: | |
990 | if (l2_entry & QCOW_OFLAG_COPIED) { | |
991 | goto out; | |
992 | } | |
bf319ece | 993 | break; |
143550a8 KW |
994 | case QCOW2_CLUSTER_UNALLOCATED: |
995 | case QCOW2_CLUSTER_COMPRESSED: | |
fdfab37d EB |
996 | case QCOW2_CLUSTER_ZERO_PLAIN: |
997 | case QCOW2_CLUSTER_ZERO_ALLOC: | |
bf319ece | 998 | break; |
143550a8 KW |
999 | default: |
1000 | abort(); | |
1001 | } | |
bf319ece KW |
1002 | } |
1003 | ||
143550a8 | 1004 | out: |
bf319ece KW |
1005 | assert(i <= nb_clusters); |
1006 | return i; | |
1007 | } | |
1008 | ||
250196f1 | 1009 | /* |
226c3c26 KW |
1010 | * Check if there already is an AIO write request in flight which allocates |
1011 | * the same cluster. In this case we need to wait until the previous | |
1012 | * request has completed and updated the L2 table accordingly. | |
65eb2e35 KW |
1013 | * |
1014 | * Returns: | |
1015 | * 0 if there was no dependency. *cur_bytes indicates the number of | |
1016 | * bytes from guest_offset that can be read before the next | |
1017 | * dependency must be processed (or the request is complete) | |
1018 | * | |
1019 | * -EAGAIN if we had to wait for another request, previously gathered | |
1020 | * information on cluster allocation may be invalid now. The caller | |
1021 | * must start over anyway, so consider *cur_bytes undefined. | |
250196f1 | 1022 | */ |
226c3c26 | 1023 | static int handle_dependencies(BlockDriverState *bs, uint64_t guest_offset, |
ecdd5333 | 1024 | uint64_t *cur_bytes, QCowL2Meta **m) |
250196f1 | 1025 | { |
ff99129a | 1026 | BDRVQcow2State *s = bs->opaque; |
250196f1 | 1027 | QCowL2Meta *old_alloc; |
65eb2e35 | 1028 | uint64_t bytes = *cur_bytes; |
250196f1 | 1029 | |
250196f1 KW |
1030 | QLIST_FOREACH(old_alloc, &s->cluster_allocs, next_in_flight) { |
1031 | ||
65eb2e35 KW |
1032 | uint64_t start = guest_offset; |
1033 | uint64_t end = start + bytes; | |
1034 | uint64_t old_start = l2meta_cow_start(old_alloc); | |
1035 | uint64_t old_end = l2meta_cow_end(old_alloc); | |
250196f1 | 1036 | |
d9d74f41 | 1037 | if (end <= old_start || start >= old_end) { |
250196f1 KW |
1038 | /* No intersection */ |
1039 | } else { | |
1040 | if (start < old_start) { | |
1041 | /* Stop at the start of a running allocation */ | |
65eb2e35 | 1042 | bytes = old_start - start; |
250196f1 | 1043 | } else { |
65eb2e35 | 1044 | bytes = 0; |
250196f1 KW |
1045 | } |
1046 | ||
ecdd5333 KW |
1047 | /* Stop if already an l2meta exists. After yielding, it wouldn't |
1048 | * be valid any more, so we'd have to clean up the old L2Metas | |
1049 | * and deal with requests depending on them before starting to | |
1050 | * gather new ones. Not worth the trouble. */ | |
1051 | if (bytes == 0 && *m) { | |
1052 | *cur_bytes = 0; | |
1053 | return 0; | |
1054 | } | |
1055 | ||
65eb2e35 | 1056 | if (bytes == 0) { |
250196f1 KW |
1057 | /* Wait for the dependency to complete. We need to recheck |
1058 | * the free/allocated clusters when we continue. */ | |
1ace7cea | 1059 | qemu_co_queue_wait(&old_alloc->dependent_requests, &s->lock); |
250196f1 KW |
1060 | return -EAGAIN; |
1061 | } | |
1062 | } | |
1063 | } | |
1064 | ||
65eb2e35 KW |
1065 | /* Make sure that existing clusters and new allocations are only used up to |
1066 | * the next dependency if we shortened the request above */ | |
1067 | *cur_bytes = bytes; | |
250196f1 | 1068 | |
226c3c26 KW |
1069 | return 0; |
1070 | } | |
1071 | ||
0af729ec KW |
1072 | /* |
1073 | * Checks how many already allocated clusters that don't require a copy on | |
1074 | * write there are at the given guest_offset (up to *bytes). If | |
1075 | * *host_offset is not zero, only physically contiguous clusters beginning at | |
1076 | * this host offset are counted. | |
1077 | * | |
411d62b0 KW |
1078 | * Note that guest_offset may not be cluster aligned. In this case, the |
1079 | * returned *host_offset points to exact byte referenced by guest_offset and | |
1080 | * therefore isn't cluster aligned as well. | |
0af729ec KW |
1081 | * |
1082 | * Returns: | |
1083 | * 0: if no allocated clusters are available at the given offset. | |
1084 | * *bytes is normally unchanged. It is set to 0 if the cluster | |
1085 | * is allocated and doesn't need COW, but doesn't have the right | |
1086 | * physical offset. | |
1087 | * | |
1088 | * 1: if allocated clusters that don't require a COW are available at | |
1089 | * the requested offset. *bytes may have decreased and describes | |
1090 | * the length of the area that can be written to. | |
1091 | * | |
1092 | * -errno: in error cases | |
0af729ec KW |
1093 | */ |
1094 | static int handle_copied(BlockDriverState *bs, uint64_t guest_offset, | |
c53ede9f | 1095 | uint64_t *host_offset, uint64_t *bytes, QCowL2Meta **m) |
0af729ec | 1096 | { |
ff99129a | 1097 | BDRVQcow2State *s = bs->opaque; |
0af729ec KW |
1098 | int l2_index; |
1099 | uint64_t cluster_offset; | |
1100 | uint64_t *l2_table; | |
b6d36def | 1101 | uint64_t nb_clusters; |
c53ede9f | 1102 | unsigned int keep_clusters; |
a3f1afb4 | 1103 | int ret; |
0af729ec KW |
1104 | |
1105 | trace_qcow2_handle_copied(qemu_coroutine_self(), guest_offset, *host_offset, | |
1106 | *bytes); | |
0af729ec | 1107 | |
411d62b0 KW |
1108 | assert(*host_offset == 0 || offset_into_cluster(s, guest_offset) |
1109 | == offset_into_cluster(s, *host_offset)); | |
1110 | ||
acb0467f KW |
1111 | /* |
1112 | * Calculate the number of clusters to look for. We stop at L2 table | |
1113 | * boundaries to keep things simple. | |
1114 | */ | |
1115 | nb_clusters = | |
1116 | size_to_clusters(s, offset_into_cluster(s, guest_offset) + *bytes); | |
1117 | ||
1118 | l2_index = offset_to_l2_index(s, guest_offset); | |
1119 | nb_clusters = MIN(nb_clusters, s->l2_size - l2_index); | |
b6d36def | 1120 | assert(nb_clusters <= INT_MAX); |
acb0467f | 1121 | |
0af729ec KW |
1122 | /* Find L2 entry for the first involved cluster */ |
1123 | ret = get_cluster_table(bs, guest_offset, &l2_table, &l2_index); | |
1124 | if (ret < 0) { | |
1125 | return ret; | |
1126 | } | |
1127 | ||
1128 | cluster_offset = be64_to_cpu(l2_table[l2_index]); | |
1129 | ||
1130 | /* Check how many clusters are already allocated and don't need COW */ | |
1131 | if (qcow2_get_cluster_type(cluster_offset) == QCOW2_CLUSTER_NORMAL | |
1132 | && (cluster_offset & QCOW_OFLAG_COPIED)) | |
1133 | { | |
e62daaf6 KW |
1134 | /* If a specific host_offset is required, check it */ |
1135 | bool offset_matches = | |
1136 | (cluster_offset & L2E_OFFSET_MASK) == *host_offset; | |
1137 | ||
a97c67ee HR |
1138 | if (offset_into_cluster(s, cluster_offset & L2E_OFFSET_MASK)) { |
1139 | qcow2_signal_corruption(bs, true, -1, -1, "Data cluster offset " | |
1140 | "%#llx unaligned (guest offset: %#" PRIx64 | |
1141 | ")", cluster_offset & L2E_OFFSET_MASK, | |
1142 | guest_offset); | |
1143 | ret = -EIO; | |
1144 | goto out; | |
1145 | } | |
1146 | ||
e62daaf6 KW |
1147 | if (*host_offset != 0 && !offset_matches) { |
1148 | *bytes = 0; | |
1149 | ret = 0; | |
1150 | goto out; | |
1151 | } | |
1152 | ||
0af729ec | 1153 | /* We keep all QCOW_OFLAG_COPIED clusters */ |
c53ede9f | 1154 | keep_clusters = |
acb0467f | 1155 | count_contiguous_clusters(nb_clusters, s->cluster_size, |
61653008 | 1156 | &l2_table[l2_index], |
0af729ec | 1157 | QCOW_OFLAG_COPIED | QCOW_OFLAG_ZERO); |
c53ede9f KW |
1158 | assert(keep_clusters <= nb_clusters); |
1159 | ||
1160 | *bytes = MIN(*bytes, | |
1161 | keep_clusters * s->cluster_size | |
1162 | - offset_into_cluster(s, guest_offset)); | |
0af729ec KW |
1163 | |
1164 | ret = 1; | |
1165 | } else { | |
0af729ec KW |
1166 | ret = 0; |
1167 | } | |
1168 | ||
0af729ec | 1169 | /* Cleanup */ |
e62daaf6 | 1170 | out: |
a3f1afb4 | 1171 | qcow2_cache_put(bs, s->l2_table_cache, (void **) &l2_table); |
0af729ec | 1172 | |
e62daaf6 KW |
1173 | /* Only return a host offset if we actually made progress. Otherwise we |
1174 | * would make requirements for handle_alloc() that it can't fulfill */ | |
a97c67ee | 1175 | if (ret > 0) { |
411d62b0 KW |
1176 | *host_offset = (cluster_offset & L2E_OFFSET_MASK) |
1177 | + offset_into_cluster(s, guest_offset); | |
e62daaf6 KW |
1178 | } |
1179 | ||
0af729ec KW |
1180 | return ret; |
1181 | } | |
1182 | ||
226c3c26 KW |
1183 | /* |
1184 | * Allocates new clusters for the given guest_offset. | |
1185 | * | |
1186 | * At most *nb_clusters are allocated, and on return *nb_clusters is updated to | |
1187 | * contain the number of clusters that have been allocated and are contiguous | |
1188 | * in the image file. | |
1189 | * | |
1190 | * If *host_offset is non-zero, it specifies the offset in the image file at | |
1191 | * which the new clusters must start. *nb_clusters can be 0 on return in this | |
1192 | * case if the cluster at host_offset is already in use. If *host_offset is | |
1193 | * zero, the clusters can be allocated anywhere in the image file. | |
1194 | * | |
1195 | * *host_offset is updated to contain the offset into the image file at which | |
1196 | * the first allocated cluster starts. | |
1197 | * | |
1198 | * Return 0 on success and -errno in error cases. -EAGAIN means that the | |
1199 | * function has been waiting for another request and the allocation must be | |
1200 | * restarted, but the whole request should not be failed. | |
1201 | */ | |
1202 | static int do_alloc_cluster_offset(BlockDriverState *bs, uint64_t guest_offset, | |
b6d36def | 1203 | uint64_t *host_offset, uint64_t *nb_clusters) |
226c3c26 | 1204 | { |
ff99129a | 1205 | BDRVQcow2State *s = bs->opaque; |
226c3c26 KW |
1206 | |
1207 | trace_qcow2_do_alloc_clusters_offset(qemu_coroutine_self(), guest_offset, | |
1208 | *host_offset, *nb_clusters); | |
1209 | ||
250196f1 KW |
1210 | /* Allocate new clusters */ |
1211 | trace_qcow2_cluster_alloc_phys(qemu_coroutine_self()); | |
1212 | if (*host_offset == 0) { | |
df021791 KW |
1213 | int64_t cluster_offset = |
1214 | qcow2_alloc_clusters(bs, *nb_clusters * s->cluster_size); | |
1215 | if (cluster_offset < 0) { | |
1216 | return cluster_offset; | |
1217 | } | |
1218 | *host_offset = cluster_offset; | |
1219 | return 0; | |
250196f1 | 1220 | } else { |
b6d36def | 1221 | int64_t ret = qcow2_alloc_clusters_at(bs, *host_offset, *nb_clusters); |
df021791 KW |
1222 | if (ret < 0) { |
1223 | return ret; | |
1224 | } | |
1225 | *nb_clusters = ret; | |
1226 | return 0; | |
250196f1 | 1227 | } |
250196f1 KW |
1228 | } |
1229 | ||
10f0ed8b KW |
1230 | /* |
1231 | * Allocates new clusters for an area that either is yet unallocated or needs a | |
1232 | * copy on write. If *host_offset is non-zero, clusters are only allocated if | |
1233 | * the new allocation can match the specified host offset. | |
1234 | * | |
411d62b0 KW |
1235 | * Note that guest_offset may not be cluster aligned. In this case, the |
1236 | * returned *host_offset points to exact byte referenced by guest_offset and | |
1237 | * therefore isn't cluster aligned as well. | |
10f0ed8b KW |
1238 | * |
1239 | * Returns: | |
1240 | * 0: if no clusters could be allocated. *bytes is set to 0, | |
1241 | * *host_offset is left unchanged. | |
1242 | * | |
1243 | * 1: if new clusters were allocated. *bytes may be decreased if the | |
1244 | * new allocation doesn't cover all of the requested area. | |
1245 | * *host_offset is updated to contain the host offset of the first | |
1246 | * newly allocated cluster. | |
1247 | * | |
1248 | * -errno: in error cases | |
10f0ed8b KW |
1249 | */ |
1250 | static int handle_alloc(BlockDriverState *bs, uint64_t guest_offset, | |
c37f4cd7 | 1251 | uint64_t *host_offset, uint64_t *bytes, QCowL2Meta **m) |
10f0ed8b | 1252 | { |
ff99129a | 1253 | BDRVQcow2State *s = bs->opaque; |
10f0ed8b KW |
1254 | int l2_index; |
1255 | uint64_t *l2_table; | |
1256 | uint64_t entry; | |
b6d36def | 1257 | uint64_t nb_clusters; |
10f0ed8b | 1258 | int ret; |
564a6b69 | 1259 | bool keep_old_clusters = false; |
10f0ed8b | 1260 | |
564a6b69 | 1261 | uint64_t alloc_cluster_offset = 0; |
10f0ed8b KW |
1262 | |
1263 | trace_qcow2_handle_alloc(qemu_coroutine_self(), guest_offset, *host_offset, | |
1264 | *bytes); | |
1265 | assert(*bytes > 0); | |
1266 | ||
f5bc6350 KW |
1267 | /* |
1268 | * Calculate the number of clusters to look for. We stop at L2 table | |
1269 | * boundaries to keep things simple. | |
1270 | */ | |
c37f4cd7 KW |
1271 | nb_clusters = |
1272 | size_to_clusters(s, offset_into_cluster(s, guest_offset) + *bytes); | |
1273 | ||
f5bc6350 | 1274 | l2_index = offset_to_l2_index(s, guest_offset); |
c37f4cd7 | 1275 | nb_clusters = MIN(nb_clusters, s->l2_size - l2_index); |
b6d36def | 1276 | assert(nb_clusters <= INT_MAX); |
f5bc6350 | 1277 | |
10f0ed8b KW |
1278 | /* Find L2 entry for the first involved cluster */ |
1279 | ret = get_cluster_table(bs, guest_offset, &l2_table, &l2_index); | |
1280 | if (ret < 0) { | |
1281 | return ret; | |
1282 | } | |
1283 | ||
3b8e2e26 | 1284 | entry = be64_to_cpu(l2_table[l2_index]); |
10f0ed8b KW |
1285 | |
1286 | /* For the moment, overwrite compressed clusters one by one */ | |
1287 | if (entry & QCOW_OFLAG_COMPRESSED) { | |
1288 | nb_clusters = 1; | |
1289 | } else { | |
3b8e2e26 | 1290 | nb_clusters = count_cow_clusters(s, nb_clusters, l2_table, l2_index); |
10f0ed8b KW |
1291 | } |
1292 | ||
ecdd5333 KW |
1293 | /* This function is only called when there were no non-COW clusters, so if |
1294 | * we can't find any unallocated or COW clusters either, something is | |
1295 | * wrong with our code. */ | |
1296 | assert(nb_clusters > 0); | |
1297 | ||
fdfab37d EB |
1298 | if (qcow2_get_cluster_type(entry) == QCOW2_CLUSTER_ZERO_ALLOC && |
1299 | (entry & QCOW_OFLAG_COPIED) && | |
564a6b69 HR |
1300 | (!*host_offset || |
1301 | start_of_cluster(s, *host_offset) == (entry & L2E_OFFSET_MASK))) | |
1302 | { | |
1303 | /* Try to reuse preallocated zero clusters; contiguous normal clusters | |
1304 | * would be fine, too, but count_cow_clusters() above has limited | |
1305 | * nb_clusters already to a range of COW clusters */ | |
1306 | int preallocated_nb_clusters = | |
1307 | count_contiguous_clusters(nb_clusters, s->cluster_size, | |
1308 | &l2_table[l2_index], QCOW_OFLAG_COPIED); | |
1309 | assert(preallocated_nb_clusters > 0); | |
10f0ed8b | 1310 | |
564a6b69 HR |
1311 | nb_clusters = preallocated_nb_clusters; |
1312 | alloc_cluster_offset = entry & L2E_OFFSET_MASK; | |
10f0ed8b | 1313 | |
564a6b69 HR |
1314 | /* We want to reuse these clusters, so qcow2_alloc_cluster_link_l2() |
1315 | * should not free them. */ | |
1316 | keep_old_clusters = true; | |
10f0ed8b KW |
1317 | } |
1318 | ||
564a6b69 HR |
1319 | qcow2_cache_put(bs, s->l2_table_cache, (void **) &l2_table); |
1320 | ||
ff52aab2 | 1321 | if (!alloc_cluster_offset) { |
564a6b69 HR |
1322 | /* Allocate, if necessary at a given offset in the image file */ |
1323 | alloc_cluster_offset = start_of_cluster(s, *host_offset); | |
1324 | ret = do_alloc_cluster_offset(bs, guest_offset, &alloc_cluster_offset, | |
1325 | &nb_clusters); | |
1326 | if (ret < 0) { | |
1327 | goto fail; | |
1328 | } | |
1329 | ||
1330 | /* Can't extend contiguous allocation */ | |
1331 | if (nb_clusters == 0) { | |
1332 | *bytes = 0; | |
1333 | return 0; | |
1334 | } | |
1335 | ||
1336 | /* !*host_offset would overwrite the image header and is reserved for | |
1337 | * "no host offset preferred". If 0 was a valid host offset, it'd | |
1338 | * trigger the following overlap check; do that now to avoid having an | |
1339 | * invalid value in *host_offset. */ | |
1340 | if (!alloc_cluster_offset) { | |
1341 | ret = qcow2_pre_write_overlap_check(bs, 0, alloc_cluster_offset, | |
1342 | nb_clusters * s->cluster_size); | |
1343 | assert(ret < 0); | |
1344 | goto fail; | |
1345 | } | |
ff52aab2 HR |
1346 | } |
1347 | ||
83baa9a4 KW |
1348 | /* |
1349 | * Save info needed for meta data update. | |
1350 | * | |
85567393 | 1351 | * requested_bytes: Number of bytes from the start of the first |
83baa9a4 KW |
1352 | * newly allocated cluster to the end of the (possibly shortened |
1353 | * before) write request. | |
1354 | * | |
85567393 | 1355 | * avail_bytes: Number of bytes from the start of the first |
83baa9a4 KW |
1356 | * newly allocated to the end of the last newly allocated cluster. |
1357 | * | |
85567393 | 1358 | * nb_bytes: The number of bytes from the start of the first |
83baa9a4 KW |
1359 | * newly allocated cluster to the end of the area that the write |
1360 | * request actually writes to (excluding COW at the end) | |
1361 | */ | |
85567393 KW |
1362 | uint64_t requested_bytes = *bytes + offset_into_cluster(s, guest_offset); |
1363 | int avail_bytes = MIN(INT_MAX, nb_clusters << s->cluster_bits); | |
1364 | int nb_bytes = MIN(requested_bytes, avail_bytes); | |
88c6588c | 1365 | QCowL2Meta *old_m = *m; |
83baa9a4 | 1366 | |
83baa9a4 KW |
1367 | *m = g_malloc0(sizeof(**m)); |
1368 | ||
1369 | **m = (QCowL2Meta) { | |
88c6588c KW |
1370 | .next = old_m, |
1371 | ||
411d62b0 | 1372 | .alloc_offset = alloc_cluster_offset, |
83baa9a4 KW |
1373 | .offset = start_of_cluster(s, guest_offset), |
1374 | .nb_clusters = nb_clusters, | |
83baa9a4 | 1375 | |
564a6b69 HR |
1376 | .keep_old_clusters = keep_old_clusters, |
1377 | ||
83baa9a4 KW |
1378 | .cow_start = { |
1379 | .offset = 0, | |
85567393 | 1380 | .nb_bytes = offset_into_cluster(s, guest_offset), |
83baa9a4 KW |
1381 | }, |
1382 | .cow_end = { | |
85567393 KW |
1383 | .offset = nb_bytes, |
1384 | .nb_bytes = avail_bytes - nb_bytes, | |
83baa9a4 KW |
1385 | }, |
1386 | }; | |
1387 | qemu_co_queue_init(&(*m)->dependent_requests); | |
1388 | QLIST_INSERT_HEAD(&s->cluster_allocs, *m, next_in_flight); | |
1389 | ||
411d62b0 | 1390 | *host_offset = alloc_cluster_offset + offset_into_cluster(s, guest_offset); |
85567393 | 1391 | *bytes = MIN(*bytes, nb_bytes - offset_into_cluster(s, guest_offset)); |
83baa9a4 KW |
1392 | assert(*bytes != 0); |
1393 | ||
10f0ed8b KW |
1394 | return 1; |
1395 | ||
1396 | fail: | |
1397 | if (*m && (*m)->nb_clusters > 0) { | |
1398 | QLIST_REMOVE(*m, next_in_flight); | |
1399 | } | |
1400 | return ret; | |
1401 | } | |
1402 | ||
45aba42f KW |
1403 | /* |
1404 | * alloc_cluster_offset | |
1405 | * | |
250196f1 KW |
1406 | * For a given offset on the virtual disk, find the cluster offset in qcow2 |
1407 | * file. If the offset is not found, allocate a new cluster. | |
45aba42f | 1408 | * |
250196f1 | 1409 | * If the cluster was already allocated, m->nb_clusters is set to 0 and |
a7912369 | 1410 | * other fields in m are meaningless. |
148da7ea KW |
1411 | * |
1412 | * If the cluster is newly allocated, m->nb_clusters is set to the number of | |
68d100e9 KW |
1413 | * contiguous clusters that have been allocated. In this case, the other |
1414 | * fields of m are valid and contain information about the first allocated | |
1415 | * cluster. | |
45aba42f | 1416 | * |
68d100e9 KW |
1417 | * If the request conflicts with another write request in flight, the coroutine |
1418 | * is queued and will be reentered when the dependency has completed. | |
148da7ea KW |
1419 | * |
1420 | * Return 0 on success and -errno in error cases | |
45aba42f | 1421 | */ |
f4f0d391 | 1422 | int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset, |
d46a0bb2 KW |
1423 | unsigned int *bytes, uint64_t *host_offset, |
1424 | QCowL2Meta **m) | |
45aba42f | 1425 | { |
ff99129a | 1426 | BDRVQcow2State *s = bs->opaque; |
710c2496 | 1427 | uint64_t start, remaining; |
250196f1 | 1428 | uint64_t cluster_offset; |
65eb2e35 | 1429 | uint64_t cur_bytes; |
710c2496 | 1430 | int ret; |
45aba42f | 1431 | |
d46a0bb2 | 1432 | trace_qcow2_alloc_clusters_offset(qemu_coroutine_self(), offset, *bytes); |
710c2496 | 1433 | |
72424114 | 1434 | again: |
16f0587e | 1435 | start = offset; |
d46a0bb2 | 1436 | remaining = *bytes; |
0af729ec KW |
1437 | cluster_offset = 0; |
1438 | *host_offset = 0; | |
ecdd5333 KW |
1439 | cur_bytes = 0; |
1440 | *m = NULL; | |
0af729ec | 1441 | |
2c3b32d2 | 1442 | while (true) { |
ecdd5333 KW |
1443 | |
1444 | if (!*host_offset) { | |
1445 | *host_offset = start_of_cluster(s, cluster_offset); | |
1446 | } | |
1447 | ||
1448 | assert(remaining >= cur_bytes); | |
1449 | ||
1450 | start += cur_bytes; | |
1451 | remaining -= cur_bytes; | |
1452 | cluster_offset += cur_bytes; | |
1453 | ||
1454 | if (remaining == 0) { | |
1455 | break; | |
1456 | } | |
1457 | ||
1458 | cur_bytes = remaining; | |
1459 | ||
2c3b32d2 KW |
1460 | /* |
1461 | * Now start gathering as many contiguous clusters as possible: | |
1462 | * | |
1463 | * 1. Check for overlaps with in-flight allocations | |
1464 | * | |
1465 | * a) Overlap not in the first cluster -> shorten this request and | |
1466 | * let the caller handle the rest in its next loop iteration. | |
1467 | * | |
1468 | * b) Real overlaps of two requests. Yield and restart the search | |
1469 | * for contiguous clusters (the situation could have changed | |
1470 | * while we were sleeping) | |
1471 | * | |
1472 | * c) TODO: Request starts in the same cluster as the in-flight | |
1473 | * allocation ends. Shorten the COW of the in-fight allocation, | |
1474 | * set cluster_offset to write to the same cluster and set up | |
1475 | * the right synchronisation between the in-flight request and | |
1476 | * the new one. | |
1477 | */ | |
ecdd5333 | 1478 | ret = handle_dependencies(bs, start, &cur_bytes, m); |
2c3b32d2 | 1479 | if (ret == -EAGAIN) { |
ecdd5333 KW |
1480 | /* Currently handle_dependencies() doesn't yield if we already had |
1481 | * an allocation. If it did, we would have to clean up the L2Meta | |
1482 | * structs before starting over. */ | |
1483 | assert(*m == NULL); | |
2c3b32d2 KW |
1484 | goto again; |
1485 | } else if (ret < 0) { | |
1486 | return ret; | |
ecdd5333 KW |
1487 | } else if (cur_bytes == 0) { |
1488 | break; | |
2c3b32d2 KW |
1489 | } else { |
1490 | /* handle_dependencies() may have decreased cur_bytes (shortened | |
1491 | * the allocations below) so that the next dependency is processed | |
1492 | * correctly during the next loop iteration. */ | |
0af729ec | 1493 | } |
710c2496 | 1494 | |
2c3b32d2 KW |
1495 | /* |
1496 | * 2. Count contiguous COPIED clusters. | |
1497 | */ | |
1498 | ret = handle_copied(bs, start, &cluster_offset, &cur_bytes, m); | |
1499 | if (ret < 0) { | |
1500 | return ret; | |
1501 | } else if (ret) { | |
ecdd5333 | 1502 | continue; |
2c3b32d2 KW |
1503 | } else if (cur_bytes == 0) { |
1504 | break; | |
1505 | } | |
060bee89 | 1506 | |
2c3b32d2 KW |
1507 | /* |
1508 | * 3. If the request still hasn't completed, allocate new clusters, | |
1509 | * considering any cluster_offset of steps 1c or 2. | |
1510 | */ | |
1511 | ret = handle_alloc(bs, start, &cluster_offset, &cur_bytes, m); | |
1512 | if (ret < 0) { | |
1513 | return ret; | |
1514 | } else if (ret) { | |
ecdd5333 | 1515 | continue; |
2c3b32d2 KW |
1516 | } else { |
1517 | assert(cur_bytes == 0); | |
1518 | break; | |
1519 | } | |
f5bc6350 | 1520 | } |
10f0ed8b | 1521 | |
d46a0bb2 KW |
1522 | *bytes -= remaining; |
1523 | assert(*bytes > 0); | |
710c2496 | 1524 | assert(*host_offset != 0); |
45aba42f | 1525 | |
148da7ea | 1526 | return 0; |
45aba42f KW |
1527 | } |
1528 | ||
1529 | static int decompress_buffer(uint8_t *out_buf, int out_buf_size, | |
1530 | const uint8_t *buf, int buf_size) | |
1531 | { | |
1532 | z_stream strm1, *strm = &strm1; | |
1533 | int ret, out_len; | |
1534 | ||
1535 | memset(strm, 0, sizeof(*strm)); | |
1536 | ||
1537 | strm->next_in = (uint8_t *)buf; | |
1538 | strm->avail_in = buf_size; | |
1539 | strm->next_out = out_buf; | |
1540 | strm->avail_out = out_buf_size; | |
1541 | ||
1542 | ret = inflateInit2(strm, -12); | |
1543 | if (ret != Z_OK) | |
1544 | return -1; | |
1545 | ret = inflate(strm, Z_FINISH); | |
1546 | out_len = strm->next_out - out_buf; | |
1547 | if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || | |
1548 | out_len != out_buf_size) { | |
1549 | inflateEnd(strm); | |
1550 | return -1; | |
1551 | } | |
1552 | inflateEnd(strm); | |
1553 | return 0; | |
1554 | } | |
1555 | ||
66f82cee | 1556 | int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset) |
45aba42f | 1557 | { |
ff99129a | 1558 | BDRVQcow2State *s = bs->opaque; |
45aba42f KW |
1559 | int ret, csize, nb_csectors, sector_offset; |
1560 | uint64_t coffset; | |
1561 | ||
1562 | coffset = cluster_offset & s->cluster_offset_mask; | |
1563 | if (s->cluster_cache_offset != coffset) { | |
1564 | nb_csectors = ((cluster_offset >> s->csize_shift) & s->csize_mask) + 1; | |
1565 | sector_offset = coffset & 511; | |
1566 | csize = nb_csectors * 512 - sector_offset; | |
3e4c7052 SH |
1567 | |
1568 | /* Allocate buffers on first decompress operation, most images are | |
1569 | * uncompressed and the memory overhead can be avoided. The buffers | |
1570 | * are freed in .bdrv_close(). | |
1571 | */ | |
1572 | if (!s->cluster_data) { | |
1573 | /* one more sector for decompressed data alignment */ | |
1574 | s->cluster_data = qemu_try_blockalign(bs->file->bs, | |
1575 | QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size + 512); | |
1576 | if (!s->cluster_data) { | |
1577 | return -ENOMEM; | |
1578 | } | |
1579 | } | |
1580 | if (!s->cluster_cache) { | |
1581 | s->cluster_cache = g_malloc(s->cluster_size); | |
1582 | } | |
1583 | ||
66f82cee | 1584 | BLKDBG_EVENT(bs->file, BLKDBG_READ_COMPRESSED); |
fbcbbf4e | 1585 | ret = bdrv_read(bs->file, coffset >> 9, s->cluster_data, |
9a4f4c31 | 1586 | nb_csectors); |
45aba42f | 1587 | if (ret < 0) { |
8af36488 | 1588 | return ret; |
45aba42f KW |
1589 | } |
1590 | if (decompress_buffer(s->cluster_cache, s->cluster_size, | |
1591 | s->cluster_data + sector_offset, csize) < 0) { | |
8af36488 | 1592 | return -EIO; |
45aba42f KW |
1593 | } |
1594 | s->cluster_cache_offset = coffset; | |
1595 | } | |
1596 | return 0; | |
1597 | } | |
5ea929e3 KW |
1598 | |
1599 | /* | |
1600 | * This discards as many clusters of nb_clusters as possible at once (i.e. | |
1601 | * all clusters in the same L2 table) and returns the number of discarded | |
1602 | * clusters. | |
1603 | */ | |
1604 | static int discard_single_l2(BlockDriverState *bs, uint64_t offset, | |
b6d36def HR |
1605 | uint64_t nb_clusters, enum qcow2_discard_type type, |
1606 | bool full_discard) | |
5ea929e3 | 1607 | { |
ff99129a | 1608 | BDRVQcow2State *s = bs->opaque; |
3948d1d4 | 1609 | uint64_t *l2_table; |
5ea929e3 KW |
1610 | int l2_index; |
1611 | int ret; | |
1612 | int i; | |
1613 | ||
3948d1d4 | 1614 | ret = get_cluster_table(bs, offset, &l2_table, &l2_index); |
5ea929e3 KW |
1615 | if (ret < 0) { |
1616 | return ret; | |
1617 | } | |
1618 | ||
1619 | /* Limit nb_clusters to one L2 table */ | |
1620 | nb_clusters = MIN(nb_clusters, s->l2_size - l2_index); | |
b6d36def | 1621 | assert(nb_clusters <= INT_MAX); |
5ea929e3 KW |
1622 | |
1623 | for (i = 0; i < nb_clusters; i++) { | |
c883db0d | 1624 | uint64_t old_l2_entry; |
5ea929e3 | 1625 | |
c883db0d | 1626 | old_l2_entry = be64_to_cpu(l2_table[l2_index + i]); |
a71835a0 KW |
1627 | |
1628 | /* | |
808c4b6f HR |
1629 | * If full_discard is false, make sure that a discarded area reads back |
1630 | * as zeroes for v3 images (we cannot do it for v2 without actually | |
1631 | * writing a zero-filled buffer). We can skip the operation if the | |
1632 | * cluster is already marked as zero, or if it's unallocated and we | |
1633 | * don't have a backing file. | |
a71835a0 | 1634 | * |
237d78f8 | 1635 | * TODO We might want to use bdrv_block_status(bs) here, but we're |
a71835a0 | 1636 | * holding s->lock, so that doesn't work today. |
808c4b6f HR |
1637 | * |
1638 | * If full_discard is true, the sector should not read back as zeroes, | |
1639 | * but rather fall through to the backing file. | |
a71835a0 | 1640 | */ |
c883db0d | 1641 | switch (qcow2_get_cluster_type(old_l2_entry)) { |
bbd995d8 EB |
1642 | case QCOW2_CLUSTER_UNALLOCATED: |
1643 | if (full_discard || !bs->backing) { | |
1644 | continue; | |
1645 | } | |
1646 | break; | |
1647 | ||
fdfab37d EB |
1648 | case QCOW2_CLUSTER_ZERO_PLAIN: |
1649 | if (!full_discard) { | |
bbd995d8 EB |
1650 | continue; |
1651 | } | |
1652 | break; | |
1653 | ||
fdfab37d | 1654 | case QCOW2_CLUSTER_ZERO_ALLOC: |
bbd995d8 EB |
1655 | case QCOW2_CLUSTER_NORMAL: |
1656 | case QCOW2_CLUSTER_COMPRESSED: | |
1657 | break; | |
1658 | ||
1659 | default: | |
1660 | abort(); | |
5ea929e3 KW |
1661 | } |
1662 | ||
1663 | /* First remove L2 entries */ | |
72e80b89 | 1664 | qcow2_cache_entry_mark_dirty(bs, s->l2_table_cache, l2_table); |
808c4b6f | 1665 | if (!full_discard && s->qcow_version >= 3) { |
a71835a0 KW |
1666 | l2_table[l2_index + i] = cpu_to_be64(QCOW_OFLAG_ZERO); |
1667 | } else { | |
1668 | l2_table[l2_index + i] = cpu_to_be64(0); | |
1669 | } | |
5ea929e3 KW |
1670 | |
1671 | /* Then decrease the refcount */ | |
c883db0d | 1672 | qcow2_free_any_clusters(bs, old_l2_entry, 1, type); |
5ea929e3 KW |
1673 | } |
1674 | ||
a3f1afb4 | 1675 | qcow2_cache_put(bs, s->l2_table_cache, (void **) &l2_table); |
5ea929e3 KW |
1676 | |
1677 | return nb_clusters; | |
1678 | } | |
1679 | ||
d2cb36af EB |
1680 | int qcow2_cluster_discard(BlockDriverState *bs, uint64_t offset, |
1681 | uint64_t bytes, enum qcow2_discard_type type, | |
1682 | bool full_discard) | |
5ea929e3 | 1683 | { |
ff99129a | 1684 | BDRVQcow2State *s = bs->opaque; |
d2cb36af | 1685 | uint64_t end_offset = offset + bytes; |
b6d36def | 1686 | uint64_t nb_clusters; |
d2cb36af | 1687 | int64_t cleared; |
5ea929e3 KW |
1688 | int ret; |
1689 | ||
f10ee139 | 1690 | /* Caller must pass aligned values, except at image end */ |
0c1bd469 | 1691 | assert(QEMU_IS_ALIGNED(offset, s->cluster_size)); |
f10ee139 EB |
1692 | assert(QEMU_IS_ALIGNED(end_offset, s->cluster_size) || |
1693 | end_offset == bs->total_sectors << BDRV_SECTOR_BITS); | |
5ea929e3 | 1694 | |
d2cb36af | 1695 | nb_clusters = size_to_clusters(s, bytes); |
5ea929e3 | 1696 | |
0b919fae KW |
1697 | s->cache_discards = true; |
1698 | ||
5ea929e3 KW |
1699 | /* Each L2 table is handled by its own loop iteration */ |
1700 | while (nb_clusters > 0) { | |
d2cb36af EB |
1701 | cleared = discard_single_l2(bs, offset, nb_clusters, type, |
1702 | full_discard); | |
1703 | if (cleared < 0) { | |
1704 | ret = cleared; | |
0b919fae | 1705 | goto fail; |
5ea929e3 KW |
1706 | } |
1707 | ||
d2cb36af EB |
1708 | nb_clusters -= cleared; |
1709 | offset += (cleared * s->cluster_size); | |
5ea929e3 KW |
1710 | } |
1711 | ||
0b919fae KW |
1712 | ret = 0; |
1713 | fail: | |
1714 | s->cache_discards = false; | |
1715 | qcow2_process_discards(bs, ret); | |
1716 | ||
1717 | return ret; | |
5ea929e3 | 1718 | } |
621f0589 KW |
1719 | |
1720 | /* | |
1721 | * This zeroes as many clusters of nb_clusters as possible at once (i.e. | |
1722 | * all clusters in the same L2 table) and returns the number of zeroed | |
1723 | * clusters. | |
1724 | */ | |
1725 | static int zero_single_l2(BlockDriverState *bs, uint64_t offset, | |
170f4b2e | 1726 | uint64_t nb_clusters, int flags) |
621f0589 | 1727 | { |
ff99129a | 1728 | BDRVQcow2State *s = bs->opaque; |
621f0589 KW |
1729 | uint64_t *l2_table; |
1730 | int l2_index; | |
1731 | int ret; | |
1732 | int i; | |
06cc5e2b | 1733 | bool unmap = !!(flags & BDRV_REQ_MAY_UNMAP); |
621f0589 KW |
1734 | |
1735 | ret = get_cluster_table(bs, offset, &l2_table, &l2_index); | |
1736 | if (ret < 0) { | |
1737 | return ret; | |
1738 | } | |
1739 | ||
1740 | /* Limit nb_clusters to one L2 table */ | |
1741 | nb_clusters = MIN(nb_clusters, s->l2_size - l2_index); | |
b6d36def | 1742 | assert(nb_clusters <= INT_MAX); |
621f0589 KW |
1743 | |
1744 | for (i = 0; i < nb_clusters; i++) { | |
1745 | uint64_t old_offset; | |
06cc5e2b | 1746 | QCow2ClusterType cluster_type; |
621f0589 KW |
1747 | |
1748 | old_offset = be64_to_cpu(l2_table[l2_index + i]); | |
1749 | ||
06cc5e2b EB |
1750 | /* |
1751 | * Minimize L2 changes if the cluster already reads back as | |
1752 | * zeroes with correct allocation. | |
1753 | */ | |
1754 | cluster_type = qcow2_get_cluster_type(old_offset); | |
1755 | if (cluster_type == QCOW2_CLUSTER_ZERO_PLAIN || | |
1756 | (cluster_type == QCOW2_CLUSTER_ZERO_ALLOC && !unmap)) { | |
1757 | continue; | |
1758 | } | |
1759 | ||
72e80b89 | 1760 | qcow2_cache_entry_mark_dirty(bs, s->l2_table_cache, l2_table); |
06cc5e2b | 1761 | if (cluster_type == QCOW2_CLUSTER_COMPRESSED || unmap) { |
621f0589 | 1762 | l2_table[l2_index + i] = cpu_to_be64(QCOW_OFLAG_ZERO); |
6cfcb9b8 | 1763 | qcow2_free_any_clusters(bs, old_offset, 1, QCOW2_DISCARD_REQUEST); |
621f0589 KW |
1764 | } else { |
1765 | l2_table[l2_index + i] |= cpu_to_be64(QCOW_OFLAG_ZERO); | |
1766 | } | |
1767 | } | |
1768 | ||
a3f1afb4 | 1769 | qcow2_cache_put(bs, s->l2_table_cache, (void **) &l2_table); |
621f0589 KW |
1770 | |
1771 | return nb_clusters; | |
1772 | } | |
1773 | ||
d2cb36af EB |
1774 | int qcow2_cluster_zeroize(BlockDriverState *bs, uint64_t offset, |
1775 | uint64_t bytes, int flags) | |
621f0589 | 1776 | { |
ff99129a | 1777 | BDRVQcow2State *s = bs->opaque; |
d2cb36af | 1778 | uint64_t end_offset = offset + bytes; |
b6d36def | 1779 | uint64_t nb_clusters; |
d2cb36af | 1780 | int64_t cleared; |
621f0589 KW |
1781 | int ret; |
1782 | ||
f10ee139 EB |
1783 | /* Caller must pass aligned values, except at image end */ |
1784 | assert(QEMU_IS_ALIGNED(offset, s->cluster_size)); | |
1785 | assert(QEMU_IS_ALIGNED(end_offset, s->cluster_size) || | |
1786 | end_offset == bs->total_sectors << BDRV_SECTOR_BITS); | |
1787 | ||
621f0589 KW |
1788 | /* The zero flag is only supported by version 3 and newer */ |
1789 | if (s->qcow_version < 3) { | |
1790 | return -ENOTSUP; | |
1791 | } | |
1792 | ||
1793 | /* Each L2 table is handled by its own loop iteration */ | |
d2cb36af | 1794 | nb_clusters = size_to_clusters(s, bytes); |
621f0589 | 1795 | |
0b919fae KW |
1796 | s->cache_discards = true; |
1797 | ||
621f0589 | 1798 | while (nb_clusters > 0) { |
d2cb36af EB |
1799 | cleared = zero_single_l2(bs, offset, nb_clusters, flags); |
1800 | if (cleared < 0) { | |
1801 | ret = cleared; | |
0b919fae | 1802 | goto fail; |
621f0589 KW |
1803 | } |
1804 | ||
d2cb36af EB |
1805 | nb_clusters -= cleared; |
1806 | offset += (cleared * s->cluster_size); | |
621f0589 KW |
1807 | } |
1808 | ||
0b919fae KW |
1809 | ret = 0; |
1810 | fail: | |
1811 | s->cache_discards = false; | |
1812 | qcow2_process_discards(bs, ret); | |
1813 | ||
1814 | return ret; | |
621f0589 | 1815 | } |
32b6444d HR |
1816 | |
1817 | /* | |
1818 | * Expands all zero clusters in a specific L1 table (or deallocates them, for | |
1819 | * non-backed non-pre-allocated zero clusters). | |
1820 | * | |
4057a2b2 HR |
1821 | * l1_entries and *visited_l1_entries are used to keep track of progress for |
1822 | * status_cb(). l1_entries contains the total number of L1 entries and | |
1823 | * *visited_l1_entries counts all visited L1 entries. | |
32b6444d HR |
1824 | */ |
1825 | static int expand_zero_clusters_in_l1(BlockDriverState *bs, uint64_t *l1_table, | |
ecf58777 | 1826 | int l1_size, int64_t *visited_l1_entries, |
4057a2b2 | 1827 | int64_t l1_entries, |
8b13976d HR |
1828 | BlockDriverAmendStatusCB *status_cb, |
1829 | void *cb_opaque) | |
32b6444d | 1830 | { |
ff99129a | 1831 | BDRVQcow2State *s = bs->opaque; |
32b6444d HR |
1832 | bool is_active_l1 = (l1_table == s->l1_table); |
1833 | uint64_t *l2_table = NULL; | |
1834 | int ret; | |
1835 | int i, j; | |
1836 | ||
1837 | if (!is_active_l1) { | |
1838 | /* inactive L2 tables require a buffer to be stored in when loading | |
1839 | * them from disk */ | |
9a4f4c31 | 1840 | l2_table = qemu_try_blockalign(bs->file->bs, s->cluster_size); |
de82815d KW |
1841 | if (l2_table == NULL) { |
1842 | return -ENOMEM; | |
1843 | } | |
32b6444d HR |
1844 | } |
1845 | ||
1846 | for (i = 0; i < l1_size; i++) { | |
1847 | uint64_t l2_offset = l1_table[i] & L1E_OFFSET_MASK; | |
1848 | bool l2_dirty = false; | |
0e06528e | 1849 | uint64_t l2_refcount; |
32b6444d HR |
1850 | |
1851 | if (!l2_offset) { | |
1852 | /* unallocated */ | |
4057a2b2 HR |
1853 | (*visited_l1_entries)++; |
1854 | if (status_cb) { | |
8b13976d | 1855 | status_cb(bs, *visited_l1_entries, l1_entries, cb_opaque); |
4057a2b2 | 1856 | } |
32b6444d HR |
1857 | continue; |
1858 | } | |
1859 | ||
8dd93d93 HR |
1860 | if (offset_into_cluster(s, l2_offset)) { |
1861 | qcow2_signal_corruption(bs, true, -1, -1, "L2 table offset %#" | |
1862 | PRIx64 " unaligned (L1 index: %#x)", | |
1863 | l2_offset, i); | |
1864 | ret = -EIO; | |
1865 | goto fail; | |
1866 | } | |
1867 | ||
32b6444d HR |
1868 | if (is_active_l1) { |
1869 | /* get active L2 tables from cache */ | |
1870 | ret = qcow2_cache_get(bs, s->l2_table_cache, l2_offset, | |
1871 | (void **)&l2_table); | |
1872 | } else { | |
1873 | /* load inactive L2 tables from disk */ | |
fbcbbf4e | 1874 | ret = bdrv_read(bs->file, l2_offset / BDRV_SECTOR_SIZE, |
9a4f4c31 | 1875 | (void *)l2_table, s->cluster_sectors); |
32b6444d HR |
1876 | } |
1877 | if (ret < 0) { | |
1878 | goto fail; | |
1879 | } | |
1880 | ||
7324c10f HR |
1881 | ret = qcow2_get_refcount(bs, l2_offset >> s->cluster_bits, |
1882 | &l2_refcount); | |
1883 | if (ret < 0) { | |
ecf58777 HR |
1884 | goto fail; |
1885 | } | |
1886 | ||
32b6444d HR |
1887 | for (j = 0; j < s->l2_size; j++) { |
1888 | uint64_t l2_entry = be64_to_cpu(l2_table[j]); | |
ecf58777 | 1889 | int64_t offset = l2_entry & L2E_OFFSET_MASK; |
3ef95218 | 1890 | QCow2ClusterType cluster_type = qcow2_get_cluster_type(l2_entry); |
32b6444d | 1891 | |
fdfab37d EB |
1892 | if (cluster_type != QCOW2_CLUSTER_ZERO_PLAIN && |
1893 | cluster_type != QCOW2_CLUSTER_ZERO_ALLOC) { | |
32b6444d HR |
1894 | continue; |
1895 | } | |
1896 | ||
fdfab37d | 1897 | if (cluster_type == QCOW2_CLUSTER_ZERO_PLAIN) { |
760e0063 | 1898 | if (!bs->backing) { |
32b6444d HR |
1899 | /* not backed; therefore we can simply deallocate the |
1900 | * cluster */ | |
1901 | l2_table[j] = 0; | |
1902 | l2_dirty = true; | |
1903 | continue; | |
1904 | } | |
1905 | ||
1906 | offset = qcow2_alloc_clusters(bs, s->cluster_size); | |
1907 | if (offset < 0) { | |
1908 | ret = offset; | |
1909 | goto fail; | |
1910 | } | |
ecf58777 HR |
1911 | |
1912 | if (l2_refcount > 1) { | |
1913 | /* For shared L2 tables, set the refcount accordingly (it is | |
1914 | * already 1 and needs to be l2_refcount) */ | |
1915 | ret = qcow2_update_cluster_refcount(bs, | |
2aabe7c7 HR |
1916 | offset >> s->cluster_bits, |
1917 | refcount_diff(1, l2_refcount), false, | |
ecf58777 HR |
1918 | QCOW2_DISCARD_OTHER); |
1919 | if (ret < 0) { | |
1920 | qcow2_free_clusters(bs, offset, s->cluster_size, | |
1921 | QCOW2_DISCARD_OTHER); | |
1922 | goto fail; | |
1923 | } | |
1924 | } | |
32b6444d HR |
1925 | } |
1926 | ||
8dd93d93 | 1927 | if (offset_into_cluster(s, offset)) { |
bcb07dba EB |
1928 | qcow2_signal_corruption(bs, true, -1, -1, |
1929 | "Cluster allocation offset " | |
8dd93d93 HR |
1930 | "%#" PRIx64 " unaligned (L2 offset: %#" |
1931 | PRIx64 ", L2 index: %#x)", offset, | |
1932 | l2_offset, j); | |
fdfab37d | 1933 | if (cluster_type == QCOW2_CLUSTER_ZERO_PLAIN) { |
8dd93d93 HR |
1934 | qcow2_free_clusters(bs, offset, s->cluster_size, |
1935 | QCOW2_DISCARD_ALWAYS); | |
1936 | } | |
1937 | ret = -EIO; | |
1938 | goto fail; | |
1939 | } | |
1940 | ||
231bb267 | 1941 | ret = qcow2_pre_write_overlap_check(bs, 0, offset, s->cluster_size); |
32b6444d | 1942 | if (ret < 0) { |
fdfab37d | 1943 | if (cluster_type == QCOW2_CLUSTER_ZERO_PLAIN) { |
320c7066 HR |
1944 | qcow2_free_clusters(bs, offset, s->cluster_size, |
1945 | QCOW2_DISCARD_ALWAYS); | |
1946 | } | |
32b6444d HR |
1947 | goto fail; |
1948 | } | |
1949 | ||
720ff280 | 1950 | ret = bdrv_pwrite_zeroes(bs->file, offset, s->cluster_size, 0); |
32b6444d | 1951 | if (ret < 0) { |
fdfab37d | 1952 | if (cluster_type == QCOW2_CLUSTER_ZERO_PLAIN) { |
320c7066 HR |
1953 | qcow2_free_clusters(bs, offset, s->cluster_size, |
1954 | QCOW2_DISCARD_ALWAYS); | |
1955 | } | |
32b6444d HR |
1956 | goto fail; |
1957 | } | |
1958 | ||
ecf58777 HR |
1959 | if (l2_refcount == 1) { |
1960 | l2_table[j] = cpu_to_be64(offset | QCOW_OFLAG_COPIED); | |
1961 | } else { | |
1962 | l2_table[j] = cpu_to_be64(offset); | |
e390cf5a | 1963 | } |
ecf58777 | 1964 | l2_dirty = true; |
32b6444d HR |
1965 | } |
1966 | ||
1967 | if (is_active_l1) { | |
1968 | if (l2_dirty) { | |
72e80b89 | 1969 | qcow2_cache_entry_mark_dirty(bs, s->l2_table_cache, l2_table); |
32b6444d HR |
1970 | qcow2_cache_depends_on_flush(s->l2_table_cache); |
1971 | } | |
a3f1afb4 | 1972 | qcow2_cache_put(bs, s->l2_table_cache, (void **) &l2_table); |
32b6444d HR |
1973 | } else { |
1974 | if (l2_dirty) { | |
231bb267 HR |
1975 | ret = qcow2_pre_write_overlap_check(bs, |
1976 | QCOW2_OL_INACTIVE_L2 | QCOW2_OL_ACTIVE_L2, l2_offset, | |
32b6444d HR |
1977 | s->cluster_size); |
1978 | if (ret < 0) { | |
1979 | goto fail; | |
1980 | } | |
1981 | ||
18d51c4b | 1982 | ret = bdrv_write(bs->file, l2_offset / BDRV_SECTOR_SIZE, |
9a4f4c31 | 1983 | (void *)l2_table, s->cluster_sectors); |
32b6444d HR |
1984 | if (ret < 0) { |
1985 | goto fail; | |
1986 | } | |
1987 | } | |
1988 | } | |
4057a2b2 HR |
1989 | |
1990 | (*visited_l1_entries)++; | |
1991 | if (status_cb) { | |
8b13976d | 1992 | status_cb(bs, *visited_l1_entries, l1_entries, cb_opaque); |
4057a2b2 | 1993 | } |
32b6444d HR |
1994 | } |
1995 | ||
1996 | ret = 0; | |
1997 | ||
1998 | fail: | |
1999 | if (l2_table) { | |
2000 | if (!is_active_l1) { | |
2001 | qemu_vfree(l2_table); | |
2002 | } else { | |
a3f1afb4 | 2003 | qcow2_cache_put(bs, s->l2_table_cache, (void **) &l2_table); |
32b6444d HR |
2004 | } |
2005 | } | |
2006 | return ret; | |
2007 | } | |
2008 | ||
2009 | /* | |
2010 | * For backed images, expands all zero clusters on the image. For non-backed | |
2011 | * images, deallocates all non-pre-allocated zero clusters (and claims the | |
2012 | * allocation for pre-allocated ones). This is important for downgrading to a | |
2013 | * qcow2 version which doesn't yet support metadata zero clusters. | |
2014 | */ | |
4057a2b2 | 2015 | int qcow2_expand_zero_clusters(BlockDriverState *bs, |
8b13976d HR |
2016 | BlockDriverAmendStatusCB *status_cb, |
2017 | void *cb_opaque) | |
32b6444d | 2018 | { |
ff99129a | 2019 | BDRVQcow2State *s = bs->opaque; |
32b6444d | 2020 | uint64_t *l1_table = NULL; |
4057a2b2 | 2021 | int64_t l1_entries = 0, visited_l1_entries = 0; |
32b6444d HR |
2022 | int ret; |
2023 | int i, j; | |
2024 | ||
4057a2b2 HR |
2025 | if (status_cb) { |
2026 | l1_entries = s->l1_size; | |
2027 | for (i = 0; i < s->nb_snapshots; i++) { | |
2028 | l1_entries += s->snapshots[i].l1_size; | |
2029 | } | |
2030 | } | |
2031 | ||
32b6444d | 2032 | ret = expand_zero_clusters_in_l1(bs, s->l1_table, s->l1_size, |
4057a2b2 | 2033 | &visited_l1_entries, l1_entries, |
8b13976d | 2034 | status_cb, cb_opaque); |
32b6444d HR |
2035 | if (ret < 0) { |
2036 | goto fail; | |
2037 | } | |
2038 | ||
2039 | /* Inactive L1 tables may point to active L2 tables - therefore it is | |
2040 | * necessary to flush the L2 table cache before trying to access the L2 | |
2041 | * tables pointed to by inactive L1 entries (else we might try to expand | |
2042 | * zero clusters that have already been expanded); furthermore, it is also | |
2043 | * necessary to empty the L2 table cache, since it may contain tables which | |
2044 | * are now going to be modified directly on disk, bypassing the cache. | |
2045 | * qcow2_cache_empty() does both for us. */ | |
2046 | ret = qcow2_cache_empty(bs, s->l2_table_cache); | |
2047 | if (ret < 0) { | |
2048 | goto fail; | |
2049 | } | |
2050 | ||
2051 | for (i = 0; i < s->nb_snapshots; i++) { | |
d737b78c LV |
2052 | int l1_sectors = DIV_ROUND_UP(s->snapshots[i].l1_size * |
2053 | sizeof(uint64_t), BDRV_SECTOR_SIZE); | |
32b6444d HR |
2054 | |
2055 | l1_table = g_realloc(l1_table, l1_sectors * BDRV_SECTOR_SIZE); | |
2056 | ||
fbcbbf4e | 2057 | ret = bdrv_read(bs->file, |
9a4f4c31 KW |
2058 | s->snapshots[i].l1_table_offset / BDRV_SECTOR_SIZE, |
2059 | (void *)l1_table, l1_sectors); | |
32b6444d HR |
2060 | if (ret < 0) { |
2061 | goto fail; | |
2062 | } | |
2063 | ||
2064 | for (j = 0; j < s->snapshots[i].l1_size; j++) { | |
2065 | be64_to_cpus(&l1_table[j]); | |
2066 | } | |
2067 | ||
2068 | ret = expand_zero_clusters_in_l1(bs, l1_table, s->snapshots[i].l1_size, | |
4057a2b2 | 2069 | &visited_l1_entries, l1_entries, |
8b13976d | 2070 | status_cb, cb_opaque); |
32b6444d HR |
2071 | if (ret < 0) { |
2072 | goto fail; | |
2073 | } | |
2074 | } | |
2075 | ||
2076 | ret = 0; | |
2077 | ||
2078 | fail: | |
32b6444d HR |
2079 | g_free(l1_table); |
2080 | return ret; | |
2081 | } |