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c142442b 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" |
c142442b KW |
27 | #include "block/qcow2.h" |
28 | ||
541dc0d4 | 29 | typedef struct QEMU_PACKED QCowSnapshotHeader { |
c142442b KW |
30 | /* header is 8 byte aligned */ |
31 | uint64_t l1_table_offset; | |
32 | ||
33 | uint32_t l1_size; | |
34 | uint16_t id_str_size; | |
35 | uint16_t name_size; | |
36 | ||
37 | uint32_t date_sec; | |
38 | uint32_t date_nsec; | |
39 | ||
40 | uint64_t vm_clock_nsec; | |
41 | ||
42 | uint32_t vm_state_size; | |
43 | uint32_t extra_data_size; /* for extension */ | |
44 | /* extra data follows */ | |
45 | /* id_str follows */ | |
46 | /* name follows */ | |
47 | } QCowSnapshotHeader; | |
48 | ||
c2c9a466 KW |
49 | typedef struct QEMU_PACKED QCowSnapshotExtraData { |
50 | uint64_t vm_state_size_large; | |
90b27759 | 51 | uint64_t disk_size; |
c2c9a466 KW |
52 | } QCowSnapshotExtraData; |
53 | ||
ed6ccf0f | 54 | void qcow2_free_snapshots(BlockDriverState *bs) |
c142442b KW |
55 | { |
56 | BDRVQcowState *s = bs->opaque; | |
57 | int i; | |
58 | ||
59 | for(i = 0; i < s->nb_snapshots; i++) { | |
7267c094 AL |
60 | g_free(s->snapshots[i].name); |
61 | g_free(s->snapshots[i].id_str); | |
c142442b | 62 | } |
7267c094 | 63 | g_free(s->snapshots); |
c142442b KW |
64 | s->snapshots = NULL; |
65 | s->nb_snapshots = 0; | |
66 | } | |
67 | ||
ed6ccf0f | 68 | int qcow2_read_snapshots(BlockDriverState *bs) |
c142442b KW |
69 | { |
70 | BDRVQcowState *s = bs->opaque; | |
71 | QCowSnapshotHeader h; | |
c2c9a466 | 72 | QCowSnapshotExtraData extra; |
c142442b KW |
73 | QCowSnapshot *sn; |
74 | int i, id_str_size, name_size; | |
75 | int64_t offset; | |
76 | uint32_t extra_data_size; | |
42deb29f | 77 | int ret; |
c142442b KW |
78 | |
79 | if (!s->nb_snapshots) { | |
80 | s->snapshots = NULL; | |
81 | s->snapshots_size = 0; | |
82 | return 0; | |
83 | } | |
84 | ||
85 | offset = s->snapshots_offset; | |
7267c094 | 86 | s->snapshots = g_malloc0(s->nb_snapshots * sizeof(QCowSnapshot)); |
42deb29f | 87 | |
c142442b | 88 | for(i = 0; i < s->nb_snapshots; i++) { |
42deb29f | 89 | /* Read statically sized part of the snapshot header */ |
c142442b | 90 | offset = align_offset(offset, 8); |
42deb29f KW |
91 | ret = bdrv_pread(bs->file, offset, &h, sizeof(h)); |
92 | if (ret < 0) { | |
c142442b | 93 | goto fail; |
42deb29f KW |
94 | } |
95 | ||
c142442b KW |
96 | offset += sizeof(h); |
97 | sn = s->snapshots + i; | |
98 | sn->l1_table_offset = be64_to_cpu(h.l1_table_offset); | |
99 | sn->l1_size = be32_to_cpu(h.l1_size); | |
100 | sn->vm_state_size = be32_to_cpu(h.vm_state_size); | |
101 | sn->date_sec = be32_to_cpu(h.date_sec); | |
102 | sn->date_nsec = be32_to_cpu(h.date_nsec); | |
103 | sn->vm_clock_nsec = be64_to_cpu(h.vm_clock_nsec); | |
104 | extra_data_size = be32_to_cpu(h.extra_data_size); | |
105 | ||
106 | id_str_size = be16_to_cpu(h.id_str_size); | |
107 | name_size = be16_to_cpu(h.name_size); | |
108 | ||
c2c9a466 KW |
109 | /* Read extra data */ |
110 | ret = bdrv_pread(bs->file, offset, &extra, | |
111 | MIN(sizeof(extra), extra_data_size)); | |
112 | if (ret < 0) { | |
113 | goto fail; | |
114 | } | |
c142442b KW |
115 | offset += extra_data_size; |
116 | ||
c2c9a466 KW |
117 | if (extra_data_size >= 8) { |
118 | sn->vm_state_size = be64_to_cpu(extra.vm_state_size_large); | |
119 | } | |
120 | ||
90b27759 KW |
121 | if (extra_data_size >= 16) { |
122 | sn->disk_size = be64_to_cpu(extra.disk_size); | |
123 | } else { | |
124 | sn->disk_size = bs->total_sectors * BDRV_SECTOR_SIZE; | |
125 | } | |
126 | ||
42deb29f | 127 | /* Read snapshot ID */ |
7267c094 | 128 | sn->id_str = g_malloc(id_str_size + 1); |
42deb29f KW |
129 | ret = bdrv_pread(bs->file, offset, sn->id_str, id_str_size); |
130 | if (ret < 0) { | |
c142442b | 131 | goto fail; |
42deb29f | 132 | } |
c142442b KW |
133 | offset += id_str_size; |
134 | sn->id_str[id_str_size] = '\0'; | |
135 | ||
42deb29f | 136 | /* Read snapshot name */ |
7267c094 | 137 | sn->name = g_malloc(name_size + 1); |
42deb29f KW |
138 | ret = bdrv_pread(bs->file, offset, sn->name, name_size); |
139 | if (ret < 0) { | |
c142442b | 140 | goto fail; |
42deb29f | 141 | } |
c142442b KW |
142 | offset += name_size; |
143 | sn->name[name_size] = '\0'; | |
144 | } | |
42deb29f | 145 | |
c142442b KW |
146 | s->snapshots_size = offset - s->snapshots_offset; |
147 | return 0; | |
42deb29f KW |
148 | |
149 | fail: | |
ed6ccf0f | 150 | qcow2_free_snapshots(bs); |
42deb29f | 151 | return ret; |
c142442b KW |
152 | } |
153 | ||
154 | /* add at the end of the file a new list of snapshots */ | |
7c80ab3f | 155 | static int qcow2_write_snapshots(BlockDriverState *bs) |
c142442b KW |
156 | { |
157 | BDRVQcowState *s = bs->opaque; | |
158 | QCowSnapshot *sn; | |
159 | QCowSnapshotHeader h; | |
c2c9a466 | 160 | QCowSnapshotExtraData extra; |
c142442b | 161 | int i, name_size, id_str_size, snapshots_size; |
d69969c4 KW |
162 | struct { |
163 | uint32_t nb_snapshots; | |
164 | uint64_t snapshots_offset; | |
165 | } QEMU_PACKED header_data; | |
c142442b | 166 | int64_t offset, snapshots_offset; |
07fd8779 | 167 | int ret; |
c142442b KW |
168 | |
169 | /* compute the size of the snapshots */ | |
170 | offset = 0; | |
171 | for(i = 0; i < s->nb_snapshots; i++) { | |
172 | sn = s->snapshots + i; | |
173 | offset = align_offset(offset, 8); | |
174 | offset += sizeof(h); | |
c2c9a466 | 175 | offset += sizeof(extra); |
c142442b KW |
176 | offset += strlen(sn->id_str); |
177 | offset += strlen(sn->name); | |
178 | } | |
179 | snapshots_size = offset; | |
180 | ||
07fd8779 | 181 | /* Allocate space for the new snapshot list */ |
ed6ccf0f | 182 | snapshots_offset = qcow2_alloc_clusters(bs, snapshots_size); |
c142442b | 183 | offset = snapshots_offset; |
5d757b56 KW |
184 | if (offset < 0) { |
185 | return offset; | |
186 | } | |
f6977f15 SH |
187 | ret = bdrv_flush(bs); |
188 | if (ret < 0) { | |
189 | return ret; | |
190 | } | |
c142442b | 191 | |
cf93980e MR |
192 | /* The snapshot list position has not yet been updated, so these clusters |
193 | * must indeed be completely free */ | |
194 | ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT, offset, | |
0f39ac9a | 195 | snapshots_size); |
cf93980e MR |
196 | if (ret < 0) { |
197 | return ret; | |
198 | } | |
199 | ||
200 | ||
07fd8779 | 201 | /* Write all snapshots to the new list */ |
c142442b KW |
202 | for(i = 0; i < s->nb_snapshots; i++) { |
203 | sn = s->snapshots + i; | |
204 | memset(&h, 0, sizeof(h)); | |
205 | h.l1_table_offset = cpu_to_be64(sn->l1_table_offset); | |
206 | h.l1_size = cpu_to_be32(sn->l1_size); | |
c2c9a466 KW |
207 | /* If it doesn't fit in 32 bit, older implementations should treat it |
208 | * as a disk-only snapshot rather than truncate the VM state */ | |
209 | if (sn->vm_state_size <= 0xffffffff) { | |
210 | h.vm_state_size = cpu_to_be32(sn->vm_state_size); | |
211 | } | |
c142442b KW |
212 | h.date_sec = cpu_to_be32(sn->date_sec); |
213 | h.date_nsec = cpu_to_be32(sn->date_nsec); | |
214 | h.vm_clock_nsec = cpu_to_be64(sn->vm_clock_nsec); | |
c2c9a466 KW |
215 | h.extra_data_size = cpu_to_be32(sizeof(extra)); |
216 | ||
217 | memset(&extra, 0, sizeof(extra)); | |
218 | extra.vm_state_size_large = cpu_to_be64(sn->vm_state_size); | |
90b27759 | 219 | extra.disk_size = cpu_to_be64(sn->disk_size); |
c142442b KW |
220 | |
221 | id_str_size = strlen(sn->id_str); | |
222 | name_size = strlen(sn->name); | |
223 | h.id_str_size = cpu_to_be16(id_str_size); | |
224 | h.name_size = cpu_to_be16(name_size); | |
225 | offset = align_offset(offset, 8); | |
07fd8779 KW |
226 | |
227 | ret = bdrv_pwrite(bs->file, offset, &h, sizeof(h)); | |
228 | if (ret < 0) { | |
c142442b | 229 | goto fail; |
07fd8779 | 230 | } |
c142442b | 231 | offset += sizeof(h); |
07fd8779 | 232 | |
c2c9a466 KW |
233 | ret = bdrv_pwrite(bs->file, offset, &extra, sizeof(extra)); |
234 | if (ret < 0) { | |
235 | goto fail; | |
236 | } | |
237 | offset += sizeof(extra); | |
238 | ||
07fd8779 KW |
239 | ret = bdrv_pwrite(bs->file, offset, sn->id_str, id_str_size); |
240 | if (ret < 0) { | |
c142442b | 241 | goto fail; |
07fd8779 | 242 | } |
c142442b | 243 | offset += id_str_size; |
07fd8779 KW |
244 | |
245 | ret = bdrv_pwrite(bs->file, offset, sn->name, name_size); | |
246 | if (ret < 0) { | |
c142442b | 247 | goto fail; |
07fd8779 | 248 | } |
c142442b KW |
249 | offset += name_size; |
250 | } | |
251 | ||
07fd8779 KW |
252 | /* |
253 | * Update the header to point to the new snapshot table. This requires the | |
254 | * new table and its refcounts to be stable on disk. | |
07fd8779 KW |
255 | */ |
256 | ret = bdrv_flush(bs); | |
257 | if (ret < 0) { | |
258 | goto fail; | |
259 | } | |
260 | ||
d69969c4 KW |
261 | QEMU_BUILD_BUG_ON(offsetof(QCowHeader, snapshots_offset) != |
262 | offsetof(QCowHeader, nb_snapshots) + sizeof(header_data.nb_snapshots)); | |
263 | ||
264 | header_data.nb_snapshots = cpu_to_be32(s->nb_snapshots); | |
265 | header_data.snapshots_offset = cpu_to_be64(snapshots_offset); | |
07fd8779 | 266 | |
07fd8779 | 267 | ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, nb_snapshots), |
d69969c4 | 268 | &header_data, sizeof(header_data)); |
07fd8779 | 269 | if (ret < 0) { |
c142442b | 270 | goto fail; |
07fd8779 | 271 | } |
c142442b KW |
272 | |
273 | /* free the old snapshot table */ | |
6cfcb9b8 KW |
274 | qcow2_free_clusters(bs, s->snapshots_offset, s->snapshots_size, |
275 | QCOW2_DISCARD_SNAPSHOT); | |
c142442b KW |
276 | s->snapshots_offset = snapshots_offset; |
277 | s->snapshots_size = snapshots_size; | |
278 | return 0; | |
07fd8779 KW |
279 | |
280 | fail: | |
281 | return ret; | |
c142442b KW |
282 | } |
283 | ||
284 | static void find_new_snapshot_id(BlockDriverState *bs, | |
285 | char *id_str, int id_str_size) | |
286 | { | |
287 | BDRVQcowState *s = bs->opaque; | |
288 | QCowSnapshot *sn; | |
289 | int i, id, id_max = 0; | |
290 | ||
291 | for(i = 0; i < s->nb_snapshots; i++) { | |
292 | sn = s->snapshots + i; | |
293 | id = strtoul(sn->id_str, NULL, 10); | |
294 | if (id > id_max) | |
295 | id_max = id; | |
296 | } | |
297 | snprintf(id_str, id_str_size, "%d", id_max + 1); | |
298 | } | |
299 | ||
a89d89d3 WX |
300 | static int find_snapshot_by_id_and_name(BlockDriverState *bs, |
301 | const char *id, | |
302 | const char *name) | |
c142442b KW |
303 | { |
304 | BDRVQcowState *s = bs->opaque; | |
305 | int i; | |
306 | ||
a89d89d3 WX |
307 | if (id && name) { |
308 | for (i = 0; i < s->nb_snapshots; i++) { | |
309 | if (!strcmp(s->snapshots[i].id_str, id) && | |
310 | !strcmp(s->snapshots[i].name, name)) { | |
311 | return i; | |
312 | } | |
313 | } | |
314 | } else if (id) { | |
315 | for (i = 0; i < s->nb_snapshots; i++) { | |
316 | if (!strcmp(s->snapshots[i].id_str, id)) { | |
317 | return i; | |
318 | } | |
319 | } | |
320 | } else if (name) { | |
321 | for (i = 0; i < s->nb_snapshots; i++) { | |
322 | if (!strcmp(s->snapshots[i].name, name)) { | |
323 | return i; | |
324 | } | |
325 | } | |
c142442b | 326 | } |
a89d89d3 | 327 | |
c142442b KW |
328 | return -1; |
329 | } | |
330 | ||
a89d89d3 WX |
331 | static int find_snapshot_by_id_or_name(BlockDriverState *bs, |
332 | const char *id_or_name) | |
c142442b | 333 | { |
a89d89d3 | 334 | int ret; |
c142442b | 335 | |
a89d89d3 WX |
336 | ret = find_snapshot_by_id_and_name(bs, id_or_name, NULL); |
337 | if (ret >= 0) { | |
c142442b | 338 | return ret; |
c142442b | 339 | } |
a89d89d3 | 340 | return find_snapshot_by_id_and_name(bs, NULL, id_or_name); |
c142442b KW |
341 | } |
342 | ||
343 | /* if no id is provided, a new one is constructed */ | |
ed6ccf0f | 344 | int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info) |
c142442b KW |
345 | { |
346 | BDRVQcowState *s = bs->opaque; | |
d1ea98d5 KW |
347 | QCowSnapshot *new_snapshot_list = NULL; |
348 | QCowSnapshot *old_snapshot_list = NULL; | |
349 | QCowSnapshot sn1, *sn = &sn1; | |
c142442b KW |
350 | int i, ret; |
351 | uint64_t *l1_table = NULL; | |
5d757b56 | 352 | int64_t l1_table_offset; |
c142442b KW |
353 | |
354 | memset(sn, 0, sizeof(*sn)); | |
355 | ||
03343166 | 356 | /* Generate an ID if it wasn't passed */ |
c142442b | 357 | if (sn_info->id_str[0] == '\0') { |
c142442b KW |
358 | find_new_snapshot_id(bs, sn_info->id_str, sizeof(sn_info->id_str)); |
359 | } | |
360 | ||
03343166 | 361 | /* Check that the ID is unique */ |
a89d89d3 | 362 | if (find_snapshot_by_id_and_name(bs, sn_info->id_str, NULL) >= 0) { |
647cc472 | 363 | return -EEXIST; |
03343166 | 364 | } |
c142442b | 365 | |
03343166 | 366 | /* Populate sn with passed data */ |
7267c094 | 367 | sn->id_str = g_strdup(sn_info->id_str); |
7267c094 | 368 | sn->name = g_strdup(sn_info->name); |
03343166 | 369 | |
90b27759 | 370 | sn->disk_size = bs->total_sectors * BDRV_SECTOR_SIZE; |
c142442b KW |
371 | sn->vm_state_size = sn_info->vm_state_size; |
372 | sn->date_sec = sn_info->date_sec; | |
373 | sn->date_nsec = sn_info->date_nsec; | |
374 | sn->vm_clock_nsec = sn_info->vm_clock_nsec; | |
375 | ||
03343166 | 376 | /* Allocate the L1 table of the snapshot and copy the current one there. */ |
5d757b56 KW |
377 | l1_table_offset = qcow2_alloc_clusters(bs, s->l1_size * sizeof(uint64_t)); |
378 | if (l1_table_offset < 0) { | |
d1ea98d5 | 379 | ret = l1_table_offset; |
5d757b56 KW |
380 | goto fail; |
381 | } | |
382 | ||
383 | sn->l1_table_offset = l1_table_offset; | |
c142442b KW |
384 | sn->l1_size = s->l1_size; |
385 | ||
03343166 | 386 | l1_table = g_malloc(s->l1_size * sizeof(uint64_t)); |
c142442b KW |
387 | for(i = 0; i < s->l1_size; i++) { |
388 | l1_table[i] = cpu_to_be64(s->l1_table[i]); | |
389 | } | |
d1ea98d5 | 390 | |
cf93980e MR |
391 | ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT, |
392 | sn->l1_table_offset, s->l1_size * sizeof(uint64_t)); | |
393 | if (ret < 0) { | |
394 | goto fail; | |
395 | } | |
396 | ||
d1ea98d5 KW |
397 | ret = bdrv_pwrite(bs->file, sn->l1_table_offset, l1_table, |
398 | s->l1_size * sizeof(uint64_t)); | |
399 | if (ret < 0) { | |
c142442b | 400 | goto fail; |
d1ea98d5 KW |
401 | } |
402 | ||
7267c094 | 403 | g_free(l1_table); |
c142442b KW |
404 | l1_table = NULL; |
405 | ||
d1ea98d5 KW |
406 | /* |
407 | * Increase the refcounts of all clusters and make sure everything is | |
408 | * stable on disk before updating the snapshot table to contain a pointer | |
409 | * to the new L1 table. | |
410 | */ | |
411 | ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 1); | |
412 | if (ret < 0) { | |
413 | goto fail; | |
414 | } | |
415 | ||
d1ea98d5 KW |
416 | /* Append the new snapshot to the snapshot list */ |
417 | new_snapshot_list = g_malloc((s->nb_snapshots + 1) * sizeof(QCowSnapshot)); | |
c142442b | 418 | if (s->snapshots) { |
d1ea98d5 KW |
419 | memcpy(new_snapshot_list, s->snapshots, |
420 | s->nb_snapshots * sizeof(QCowSnapshot)); | |
421 | old_snapshot_list = s->snapshots; | |
c142442b | 422 | } |
d1ea98d5 | 423 | s->snapshots = new_snapshot_list; |
c142442b KW |
424 | s->snapshots[s->nb_snapshots++] = *sn; |
425 | ||
d1ea98d5 KW |
426 | ret = qcow2_write_snapshots(bs); |
427 | if (ret < 0) { | |
428 | g_free(s->snapshots); | |
429 | s->snapshots = old_snapshot_list; | |
c142442b | 430 | goto fail; |
d1ea98d5 KW |
431 | } |
432 | ||
433 | g_free(old_snapshot_list); | |
434 | ||
1ebf561c KW |
435 | /* The VM state isn't needed any more in the active L1 table; in fact, it |
436 | * hurts by causing expensive COW for the next snapshot. */ | |
437 | qcow2_discard_clusters(bs, qcow2_vm_state_offset(s), | |
438 | align_offset(sn->vm_state_size, s->cluster_size) | |
439 | >> BDRV_SECTOR_BITS, | |
440 | QCOW2_DISCARD_NEVER); | |
441 | ||
c142442b | 442 | #ifdef DEBUG_ALLOC |
6cbc3031 PH |
443 | { |
444 | BdrvCheckResult result = {0}; | |
b35278f7 | 445 | qcow2_check_refcounts(bs, &result, 0); |
6cbc3031 | 446 | } |
c142442b KW |
447 | #endif |
448 | return 0; | |
03343166 KW |
449 | |
450 | fail: | |
451 | g_free(sn->id_str); | |
7267c094 AL |
452 | g_free(sn->name); |
453 | g_free(l1_table); | |
d1ea98d5 KW |
454 | |
455 | return ret; | |
c142442b KW |
456 | } |
457 | ||
458 | /* copy the snapshot 'snapshot_name' into the current disk image */ | |
ed6ccf0f | 459 | int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id) |
c142442b KW |
460 | { |
461 | BDRVQcowState *s = bs->opaque; | |
462 | QCowSnapshot *sn; | |
35d7ace7 KW |
463 | int i, snapshot_index; |
464 | int cur_l1_bytes, sn_l1_bytes; | |
589f284b | 465 | int ret; |
43a0cac4 | 466 | uint64_t *sn_l1_table = NULL; |
c142442b | 467 | |
589f284b | 468 | /* Search the snapshot */ |
c142442b | 469 | snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_id); |
589f284b | 470 | if (snapshot_index < 0) { |
c142442b | 471 | return -ENOENT; |
589f284b | 472 | } |
c142442b KW |
473 | sn = &s->snapshots[snapshot_index]; |
474 | ||
90b27759 KW |
475 | if (sn->disk_size != bs->total_sectors * BDRV_SECTOR_SIZE) { |
476 | error_report("qcow2: Loading snapshots with different disk " | |
477 | "size is not implemented"); | |
478 | ret = -ENOTSUP; | |
479 | goto fail; | |
480 | } | |
481 | ||
589f284b KW |
482 | /* |
483 | * Make sure that the current L1 table is big enough to contain the whole | |
484 | * L1 table of the snapshot. If the snapshot L1 table is smaller, the | |
485 | * current one must be padded with zeros. | |
486 | */ | |
487 | ret = qcow2_grow_l1_table(bs, sn->l1_size, true); | |
488 | if (ret < 0) { | |
c142442b | 489 | goto fail; |
589f284b | 490 | } |
c142442b | 491 | |
35d7ace7 KW |
492 | cur_l1_bytes = s->l1_size * sizeof(uint64_t); |
493 | sn_l1_bytes = sn->l1_size * sizeof(uint64_t); | |
494 | ||
589f284b KW |
495 | /* |
496 | * Copy the snapshot L1 table to the current L1 table. | |
497 | * | |
498 | * Before overwriting the old current L1 table on disk, make sure to | |
499 | * increase all refcounts for the clusters referenced by the new one. | |
43a0cac4 KW |
500 | * Decrease the refcount referenced by the old one only when the L1 |
501 | * table is overwritten. | |
589f284b | 502 | */ |
43a0cac4 KW |
503 | sn_l1_table = g_malloc0(cur_l1_bytes); |
504 | ||
505 | ret = bdrv_pread(bs->file, sn->l1_table_offset, sn_l1_table, sn_l1_bytes); | |
506 | if (ret < 0) { | |
507 | goto fail; | |
508 | } | |
509 | ||
510 | ret = qcow2_update_snapshot_refcount(bs, sn->l1_table_offset, | |
511 | sn->l1_size, 1); | |
589f284b | 512 | if (ret < 0) { |
c142442b | 513 | goto fail; |
589f284b KW |
514 | } |
515 | ||
cf93980e MR |
516 | ret = qcow2_pre_write_overlap_check(bs, |
517 | QCOW2_OL_DEFAULT & ~QCOW2_OL_ACTIVE_L1, | |
518 | s->l1_table_offset, cur_l1_bytes); | |
519 | if (ret < 0) { | |
520 | goto fail; | |
521 | } | |
522 | ||
43a0cac4 | 523 | ret = bdrv_pwrite_sync(bs->file, s->l1_table_offset, sn_l1_table, |
589f284b KW |
524 | cur_l1_bytes); |
525 | if (ret < 0) { | |
c142442b | 526 | goto fail; |
589f284b KW |
527 | } |
528 | ||
43a0cac4 KW |
529 | /* |
530 | * Decrease refcount of clusters of current L1 table. | |
531 | * | |
532 | * At this point, the in-memory s->l1_table points to the old L1 table, | |
533 | * whereas on disk we already have the new one. | |
534 | * | |
535 | * qcow2_update_snapshot_refcount special cases the current L1 table to use | |
536 | * the in-memory data instead of really using the offset to load a new one, | |
537 | * which is why this works. | |
538 | */ | |
539 | ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset, | |
540 | s->l1_size, -1); | |
541 | ||
542 | /* | |
543 | * Now update the in-memory L1 table to be in sync with the on-disk one. We | |
544 | * need to do this even if updating refcounts failed. | |
545 | */ | |
c142442b | 546 | for(i = 0;i < s->l1_size; i++) { |
43a0cac4 | 547 | s->l1_table[i] = be64_to_cpu(sn_l1_table[i]); |
c142442b KW |
548 | } |
549 | ||
43a0cac4 KW |
550 | if (ret < 0) { |
551 | goto fail; | |
552 | } | |
553 | ||
554 | g_free(sn_l1_table); | |
555 | sn_l1_table = NULL; | |
556 | ||
557 | /* | |
558 | * Update QCOW_OFLAG_COPIED in the active L1 table (it may have changed | |
559 | * when we decreased the refcount of the old snapshot. | |
560 | */ | |
561 | ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 0); | |
589f284b | 562 | if (ret < 0) { |
c142442b | 563 | goto fail; |
589f284b | 564 | } |
c142442b KW |
565 | |
566 | #ifdef DEBUG_ALLOC | |
6cbc3031 PH |
567 | { |
568 | BdrvCheckResult result = {0}; | |
b35278f7 | 569 | qcow2_check_refcounts(bs, &result, 0); |
6cbc3031 | 570 | } |
c142442b KW |
571 | #endif |
572 | return 0; | |
589f284b KW |
573 | |
574 | fail: | |
43a0cac4 | 575 | g_free(sn_l1_table); |
589f284b | 576 | return ret; |
c142442b KW |
577 | } |
578 | ||
a89d89d3 WX |
579 | int qcow2_snapshot_delete(BlockDriverState *bs, |
580 | const char *snapshot_id, | |
581 | const char *name, | |
582 | Error **errp) | |
c142442b KW |
583 | { |
584 | BDRVQcowState *s = bs->opaque; | |
9a476780 | 585 | QCowSnapshot sn; |
c142442b KW |
586 | int snapshot_index, ret; |
587 | ||
9a476780 | 588 | /* Search the snapshot */ |
a89d89d3 | 589 | snapshot_index = find_snapshot_by_id_and_name(bs, snapshot_id, name); |
9a476780 | 590 | if (snapshot_index < 0) { |
a89d89d3 | 591 | error_setg(errp, "Can't find the snapshot"); |
c142442b | 592 | return -ENOENT; |
9a476780 KW |
593 | } |
594 | sn = s->snapshots[snapshot_index]; | |
c142442b | 595 | |
9a476780 KW |
596 | /* Remove it from the snapshot list */ |
597 | memmove(s->snapshots + snapshot_index, | |
598 | s->snapshots + snapshot_index + 1, | |
599 | (s->nb_snapshots - snapshot_index - 1) * sizeof(sn)); | |
600 | s->nb_snapshots--; | |
601 | ret = qcow2_write_snapshots(bs); | |
602 | if (ret < 0) { | |
a89d89d3 | 603 | error_setg(errp, "Failed to remove snapshot from snapshot list"); |
c142442b | 604 | return ret; |
9a476780 KW |
605 | } |
606 | ||
607 | /* | |
608 | * The snapshot is now unused, clean up. If we fail after this point, we | |
609 | * won't recover but just leak clusters. | |
610 | */ | |
611 | g_free(sn.id_str); | |
612 | g_free(sn.name); | |
613 | ||
614 | /* | |
615 | * Now decrease the refcounts of clusters referenced by the snapshot and | |
616 | * free the L1 table. | |
617 | */ | |
618 | ret = qcow2_update_snapshot_refcount(bs, sn.l1_table_offset, | |
619 | sn.l1_size, -1); | |
620 | if (ret < 0) { | |
a89d89d3 | 621 | error_setg(errp, "Failed to free the cluster and L1 table"); |
c142442b | 622 | return ret; |
9a476780 | 623 | } |
6cfcb9b8 KW |
624 | qcow2_free_clusters(bs, sn.l1_table_offset, sn.l1_size * sizeof(uint64_t), |
625 | QCOW2_DISCARD_SNAPSHOT); | |
c142442b | 626 | |
9a476780 KW |
627 | /* must update the copied flag on the current cluster offsets */ |
628 | ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 0); | |
c142442b | 629 | if (ret < 0) { |
a89d89d3 | 630 | error_setg(errp, "Failed to update snapshot status in disk"); |
c142442b KW |
631 | return ret; |
632 | } | |
9a476780 | 633 | |
c142442b | 634 | #ifdef DEBUG_ALLOC |
6cbc3031 PH |
635 | { |
636 | BdrvCheckResult result = {0}; | |
b35278f7 | 637 | qcow2_check_refcounts(bs, &result, 0); |
6cbc3031 | 638 | } |
c142442b KW |
639 | #endif |
640 | return 0; | |
641 | } | |
642 | ||
ed6ccf0f | 643 | int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab) |
c142442b KW |
644 | { |
645 | BDRVQcowState *s = bs->opaque; | |
646 | QEMUSnapshotInfo *sn_tab, *sn_info; | |
647 | QCowSnapshot *sn; | |
648 | int i; | |
649 | ||
650 | if (!s->nb_snapshots) { | |
651 | *psn_tab = NULL; | |
652 | return s->nb_snapshots; | |
653 | } | |
654 | ||
7267c094 | 655 | sn_tab = g_malloc0(s->nb_snapshots * sizeof(QEMUSnapshotInfo)); |
c142442b KW |
656 | for(i = 0; i < s->nb_snapshots; i++) { |
657 | sn_info = sn_tab + i; | |
658 | sn = s->snapshots + i; | |
659 | pstrcpy(sn_info->id_str, sizeof(sn_info->id_str), | |
660 | sn->id_str); | |
661 | pstrcpy(sn_info->name, sizeof(sn_info->name), | |
662 | sn->name); | |
663 | sn_info->vm_state_size = sn->vm_state_size; | |
664 | sn_info->date_sec = sn->date_sec; | |
665 | sn_info->date_nsec = sn->date_nsec; | |
666 | sn_info->vm_clock_nsec = sn->vm_clock_nsec; | |
667 | } | |
668 | *psn_tab = sn_tab; | |
669 | return s->nb_snapshots; | |
670 | } | |
671 | ||
51ef6727 | 672 | int qcow2_snapshot_load_tmp(BlockDriverState *bs, const char *snapshot_name) |
673 | { | |
e3f652b3 | 674 | int i, snapshot_index; |
51ef6727 | 675 | BDRVQcowState *s = bs->opaque; |
676 | QCowSnapshot *sn; | |
e3f652b3 KW |
677 | uint64_t *new_l1_table; |
678 | int new_l1_bytes; | |
679 | int ret; | |
51ef6727 | 680 | |
e3f652b3 KW |
681 | assert(bs->read_only); |
682 | ||
683 | /* Search the snapshot */ | |
51ef6727 | 684 | snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_name); |
685 | if (snapshot_index < 0) { | |
686 | return -ENOENT; | |
687 | } | |
51ef6727 | 688 | sn = &s->snapshots[snapshot_index]; |
51ef6727 | 689 | |
e3f652b3 KW |
690 | /* Allocate and read in the snapshot's L1 table */ |
691 | new_l1_bytes = s->l1_size * sizeof(uint64_t); | |
692 | new_l1_table = g_malloc0(align_offset(new_l1_bytes, 512)); | |
51ef6727 | 693 | |
e3f652b3 KW |
694 | ret = bdrv_pread(bs->file, sn->l1_table_offset, new_l1_table, new_l1_bytes); |
695 | if (ret < 0) { | |
696 | g_free(new_l1_table); | |
697 | return ret; | |
51ef6727 | 698 | } |
699 | ||
e3f652b3 KW |
700 | /* Switch the L1 table */ |
701 | g_free(s->l1_table); | |
702 | ||
703 | s->l1_size = sn->l1_size; | |
704 | s->l1_table_offset = sn->l1_table_offset; | |
705 | s->l1_table = new_l1_table; | |
706 | ||
51ef6727 | 707 | for(i = 0;i < s->l1_size; i++) { |
708 | be64_to_cpus(&s->l1_table[i]); | |
709 | } | |
e3f652b3 | 710 | |
51ef6727 | 711 | return 0; |
712 | } |