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Commit | Line | Data |
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747ff602 JC |
1 | /* |
2 | * Live block commit | |
3 | * | |
4 | * Copyright Red Hat, Inc. 2012 | |
5 | * | |
6 | * Authors: | |
7 | * Jeff Cody <jcody@redhat.com> | |
8 | * Based on stream.c by Stefan Hajnoczi | |
9 | * | |
10 | * This work is licensed under the terms of the GNU LGPL, version 2 or later. | |
11 | * See the COPYING.LIB file in the top-level directory. | |
12 | * | |
13 | */ | |
14 | ||
80c71a24 | 15 | #include "qemu/osdep.h" |
dcbf37ce | 16 | #include "qemu/cutils.h" |
747ff602 | 17 | #include "trace.h" |
737e150e | 18 | #include "block/block_int.h" |
c87621ea | 19 | #include "block/blockjob_int.h" |
da34e65c | 20 | #include "qapi/error.h" |
cc7a8ea7 | 21 | #include "qapi/qmp/qerror.h" |
747ff602 | 22 | #include "qemu/ratelimit.h" |
373340b2 | 23 | #include "sysemu/block-backend.h" |
747ff602 JC |
24 | |
25 | enum { | |
26 | /* | |
27 | * Size of data buffer for populating the image file. This should be large | |
28 | * enough to process multiple clusters in a single call, so that populating | |
29 | * contiguous regions of the image is efficient. | |
30 | */ | |
31 | COMMIT_BUFFER_SIZE = 512 * 1024, /* in bytes */ | |
32 | }; | |
33 | ||
747ff602 JC |
34 | typedef struct CommitBlockJob { |
35 | BlockJob common; | |
8dfba279 | 36 | BlockDriverState *commit_top_bs; |
4653456a KW |
37 | BlockBackend *top; |
38 | BlockBackend *base; | |
22dffcbe | 39 | BlockDriverState *base_bs; |
92aa5c6d | 40 | BlockdevOnError on_error; |
e70cdc57 | 41 | bool base_read_only; |
df827336 | 42 | bool chain_frozen; |
54e26900 | 43 | char *backing_file_str; |
747ff602 JC |
44 | } CommitBlockJob; |
45 | ||
4653456a | 46 | static int coroutine_fn commit_populate(BlockBackend *bs, BlockBackend *base, |
d8a98584 | 47 | int64_t offset, uint64_t bytes, |
747ff602 JC |
48 | void *buf) |
49 | { | |
50 | int ret = 0; | |
ee7a883a | 51 | QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes); |
747ff602 | 52 | |
d8a98584 | 53 | assert(bytes < SIZE_MAX); |
4653456a | 54 | |
d8a98584 | 55 | ret = blk_co_preadv(bs, offset, qiov.size, &qiov, 0); |
4653456a | 56 | if (ret < 0) { |
747ff602 JC |
57 | return ret; |
58 | } | |
59 | ||
d8a98584 | 60 | ret = blk_co_pwritev(base, offset, qiov.size, &qiov, 0); |
4653456a | 61 | if (ret < 0) { |
747ff602 JC |
62 | return ret; |
63 | } | |
64 | ||
65 | return 0; | |
66 | } | |
67 | ||
22dffcbe | 68 | static int commit_prepare(Job *job) |
747ff602 | 69 | { |
1908a559 | 70 | CommitBlockJob *s = container_of(job, CommitBlockJob, common.job); |
19ebd13e | 71 | |
df827336 AG |
72 | bdrv_unfreeze_backing_chain(s->commit_top_bs, s->base_bs); |
73 | s->chain_frozen = false; | |
74 | ||
8dfba279 KW |
75 | /* Remove base node parent that still uses BLK_PERM_WRITE/RESIZE before |
76 | * the normal backing chain can be restored. */ | |
77 | blk_unref(s->base); | |
22dffcbe JS |
78 | s->base = NULL; |
79 | ||
80 | /* FIXME: bdrv_drop_intermediate treats total failures and partial failures | |
81 | * identically. Further work is needed to disambiguate these cases. */ | |
82 | return bdrv_drop_intermediate(s->commit_top_bs, s->base_bs, | |
83 | s->backing_file_str); | |
84 | } | |
9e85cd5c | 85 | |
22dffcbe JS |
86 | static void commit_abort(Job *job) |
87 | { | |
88 | CommitBlockJob *s = container_of(job, CommitBlockJob, common.job); | |
89 | BlockDriverState *top_bs = blk_bs(s->top); | |
90 | ||
df827336 AG |
91 | if (s->chain_frozen) { |
92 | bdrv_unfreeze_backing_chain(s->commit_top_bs, s->base_bs); | |
93 | } | |
94 | ||
22dffcbe JS |
95 | /* Make sure commit_top_bs and top stay around until bdrv_replace_node() */ |
96 | bdrv_ref(top_bs); | |
97 | bdrv_ref(s->commit_top_bs); | |
98 | ||
99 | if (s->base) { | |
100 | blk_unref(s->base); | |
9e85cd5c SH |
101 | } |
102 | ||
22dffcbe JS |
103 | /* free the blockers on the intermediate nodes so that bdrv_replace_nodes |
104 | * can succeed */ | |
105 | block_job_remove_all_bdrv(&s->common); | |
106 | ||
107 | /* If bdrv_drop_intermediate() failed (or was not invoked), remove the | |
108 | * commit filter driver from the backing chain now. Do this as the final | |
109 | * step so that the 'consistent read' permission can be granted. | |
110 | * | |
111 | * XXX Can (or should) we somehow keep 'consistent read' blocked even | |
112 | * after the failed/cancelled commit job is gone? If we already wrote | |
113 | * something to base, the intermediate images aren't valid any more. */ | |
114 | bdrv_child_try_set_perm(s->commit_top_bs->backing, 0, BLK_PERM_ALL, | |
115 | &error_abort); | |
116 | bdrv_replace_node(s->commit_top_bs, backing_bs(s->commit_top_bs), | |
117 | &error_abort); | |
118 | ||
119 | bdrv_unref(s->commit_top_bs); | |
120 | bdrv_unref(top_bs); | |
121 | } | |
122 | ||
123 | static void commit_clean(Job *job) | |
124 | { | |
125 | CommitBlockJob *s = container_of(job, CommitBlockJob, common.job); | |
126 | ||
9e85cd5c SH |
127 | /* restore base open flags here if appropriate (e.g., change the base back |
128 | * to r/o). These reopens do not need to be atomic, since we won't abort | |
129 | * even on failure here */ | |
e70cdc57 AG |
130 | if (s->base_read_only) { |
131 | bdrv_reopen_set_read_only(s->base_bs, true, NULL); | |
9e85cd5c | 132 | } |
22dffcbe | 133 | |
9e85cd5c | 134 | g_free(s->backing_file_str); |
4653456a | 135 | blk_unref(s->top); |
9e85cd5c SH |
136 | } |
137 | ||
f67432a2 | 138 | static int coroutine_fn commit_run(Job *job, Error **errp) |
9e85cd5c | 139 | { |
f67432a2 | 140 | CommitBlockJob *s = container_of(job, CommitBlockJob, common.job); |
317a6676 | 141 | int64_t offset; |
f14a39cc | 142 | uint64_t delay_ns = 0; |
747ff602 | 143 | int ret = 0; |
51b0a488 | 144 | int64_t n = 0; /* bytes */ |
9e85cd5c | 145 | void *buf = NULL; |
747ff602 | 146 | int bytes_written = 0; |
05df8a6a | 147 | int64_t len, base_len; |
747ff602 | 148 | |
05df8a6a KW |
149 | ret = len = blk_getlength(s->top); |
150 | if (len < 0) { | |
9e85cd5c | 151 | goto out; |
747ff602 | 152 | } |
30a5c887 | 153 | job_progress_set_remaining(&s->common.job, len); |
747ff602 | 154 | |
4653456a | 155 | ret = base_len = blk_getlength(s->base); |
747ff602 | 156 | if (base_len < 0) { |
9e85cd5c | 157 | goto out; |
747ff602 JC |
158 | } |
159 | ||
05df8a6a KW |
160 | if (base_len < len) { |
161 | ret = blk_truncate(s->base, len, PREALLOC_MODE_OFF, NULL); | |
747ff602 | 162 | if (ret) { |
9e85cd5c | 163 | goto out; |
747ff602 JC |
164 | } |
165 | } | |
166 | ||
4653456a | 167 | buf = blk_blockalign(s->top, COMMIT_BUFFER_SIZE); |
747ff602 | 168 | |
05df8a6a | 169 | for (offset = 0; offset < len; offset += n) { |
747ff602 JC |
170 | bool copy; |
171 | ||
747ff602 | 172 | /* Note that even when no rate limit is applied we need to yield |
c57b6656 | 173 | * with no pending I/O here so that bdrv_drain_all() returns. |
747ff602 | 174 | */ |
5d43e86e | 175 | job_sleep_ns(&s->common.job, delay_ns); |
daa7f2f9 | 176 | if (job_is_cancelled(&s->common.job)) { |
747ff602 JC |
177 | break; |
178 | } | |
179 | /* Copy if allocated above the base */ | |
4653456a | 180 | ret = bdrv_is_allocated_above(blk_bs(s->top), blk_bs(s->base), |
51b0a488 | 181 | offset, COMMIT_BUFFER_SIZE, &n); |
747ff602 | 182 | copy = (ret == 1); |
51b0a488 | 183 | trace_commit_one_iteration(s, offset, n, ret); |
747ff602 | 184 | if (copy) { |
51b0a488 EB |
185 | ret = commit_populate(s->top, s->base, offset, n, buf); |
186 | bytes_written += n; | |
747ff602 JC |
187 | } |
188 | if (ret < 0) { | |
1e8fb7f1 KW |
189 | BlockErrorAction action = |
190 | block_job_error_action(&s->common, false, s->on_error, -ret); | |
191 | if (action == BLOCK_ERROR_ACTION_REPORT) { | |
9e85cd5c | 192 | goto out; |
747ff602 JC |
193 | } else { |
194 | n = 0; | |
195 | continue; | |
196 | } | |
197 | } | |
198 | /* Publish progress */ | |
30a5c887 | 199 | job_progress_update(&s->common.job, n); |
f14a39cc | 200 | |
dee81d51 KW |
201 | if (copy) { |
202 | delay_ns = block_job_ratelimit_get_delay(&s->common, n); | |
2fe4bba1 KW |
203 | } else { |
204 | delay_ns = 0; | |
f14a39cc | 205 | } |
747ff602 JC |
206 | } |
207 | ||
208 | ret = 0; | |
209 | ||
9e85cd5c | 210 | out: |
747ff602 JC |
211 | qemu_vfree(buf); |
212 | ||
f67432a2 | 213 | return ret; |
747ff602 JC |
214 | } |
215 | ||
3fc4b10a | 216 | static const BlockJobDriver commit_job_driver = { |
33e9e9bd KW |
217 | .job_driver = { |
218 | .instance_size = sizeof(CommitBlockJob), | |
252291ea | 219 | .job_type = JOB_TYPE_COMMIT, |
80fa2c75 | 220 | .free = block_job_free, |
b15de828 | 221 | .user_resume = block_job_user_resume, |
b69f777d | 222 | .drain = block_job_drain, |
f67432a2 | 223 | .run = commit_run, |
22dffcbe JS |
224 | .prepare = commit_prepare, |
225 | .abort = commit_abort, | |
226 | .clean = commit_clean | |
33e9e9bd | 227 | }, |
747ff602 JC |
228 | }; |
229 | ||
8dfba279 KW |
230 | static int coroutine_fn bdrv_commit_top_preadv(BlockDriverState *bs, |
231 | uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags) | |
232 | { | |
233 | return bdrv_co_preadv(bs->backing, offset, bytes, qiov, flags); | |
234 | } | |
235 | ||
998b3a1e | 236 | static void bdrv_commit_top_refresh_filename(BlockDriverState *bs) |
dcbf37ce | 237 | { |
dcbf37ce KW |
238 | pstrcpy(bs->exact_filename, sizeof(bs->exact_filename), |
239 | bs->backing->bs->filename); | |
240 | } | |
91965658 | 241 | |
8dfba279 KW |
242 | static void bdrv_commit_top_child_perm(BlockDriverState *bs, BdrvChild *c, |
243 | const BdrvChildRole *role, | |
e0995dc3 | 244 | BlockReopenQueue *reopen_queue, |
8dfba279 KW |
245 | uint64_t perm, uint64_t shared, |
246 | uint64_t *nperm, uint64_t *nshared) | |
247 | { | |
248 | *nperm = 0; | |
249 | *nshared = BLK_PERM_ALL; | |
250 | } | |
251 | ||
252 | /* Dummy node that provides consistent read to its users without requiring it | |
253 | * from its backing file and that allows writes on the backing file chain. */ | |
254 | static BlockDriver bdrv_commit_top = { | |
91965658 KW |
255 | .format_name = "commit_top", |
256 | .bdrv_co_preadv = bdrv_commit_top_preadv, | |
3e4d0e72 | 257 | .bdrv_co_block_status = bdrv_co_block_status_from_backing, |
dcbf37ce | 258 | .bdrv_refresh_filename = bdrv_commit_top_refresh_filename, |
91965658 | 259 | .bdrv_child_perm = bdrv_commit_top_child_perm, |
8dfba279 KW |
260 | }; |
261 | ||
fd62c609 | 262 | void commit_start(const char *job_id, BlockDriverState *bs, |
5360782d JS |
263 | BlockDriverState *base, BlockDriverState *top, |
264 | int creation_flags, int64_t speed, | |
8254b6d9 | 265 | BlockdevOnError on_error, const char *backing_file_str, |
0db832f4 | 266 | const char *filter_node_name, Error **errp) |
747ff602 JC |
267 | { |
268 | CommitBlockJob *s; | |
3e4c5122 | 269 | BlockDriverState *iter; |
8dfba279 | 270 | BlockDriverState *commit_top_bs = NULL; |
747ff602 | 271 | Error *local_err = NULL; |
d7086422 | 272 | int ret; |
747ff602 | 273 | |
18da7f94 | 274 | assert(top != bs); |
747ff602 JC |
275 | if (top == base) { |
276 | error_setg(errp, "Invalid files for merge: top and base are the same"); | |
277 | return; | |
278 | } | |
279 | ||
75859b94 | 280 | s = block_job_create(job_id, &commit_job_driver, NULL, bs, 0, BLK_PERM_ALL, |
5360782d | 281 | speed, creation_flags, NULL, NULL, errp); |
834fe28d AG |
282 | if (!s) { |
283 | return; | |
284 | } | |
285 | ||
bde70715 | 286 | /* convert base to r/w, if necessary */ |
e70cdc57 AG |
287 | s->base_read_only = bdrv_is_read_only(base); |
288 | if (s->base_read_only) { | |
289 | if (bdrv_reopen_set_read_only(base, false, errp) != 0) { | |
d7086422 | 290 | goto fail; |
747ff602 JC |
291 | } |
292 | } | |
293 | ||
8dfba279 KW |
294 | /* Insert commit_top block node above top, so we can block consistent read |
295 | * on the backing chain below it */ | |
0db832f4 KW |
296 | commit_top_bs = bdrv_new_open_driver(&bdrv_commit_top, filter_node_name, 0, |
297 | errp); | |
8dfba279 KW |
298 | if (commit_top_bs == NULL) { |
299 | goto fail; | |
300 | } | |
d3c8c674 KW |
301 | if (!filter_node_name) { |
302 | commit_top_bs->implicit = true; | |
303 | } | |
0d0676a1 | 304 | commit_top_bs->total_sectors = top->total_sectors; |
02be4aeb | 305 | bdrv_set_aio_context(commit_top_bs, bdrv_get_aio_context(top)); |
8dfba279 | 306 | |
b69f00dd FZ |
307 | bdrv_set_backing_hd(commit_top_bs, top, &local_err); |
308 | if (local_err) { | |
309 | bdrv_unref(commit_top_bs); | |
310 | commit_top_bs = NULL; | |
311 | error_propagate(errp, local_err); | |
312 | goto fail; | |
313 | } | |
61f09cea | 314 | bdrv_replace_node(top, commit_top_bs, &local_err); |
b69f00dd FZ |
315 | if (local_err) { |
316 | bdrv_unref(commit_top_bs); | |
317 | commit_top_bs = NULL; | |
318 | error_propagate(errp, local_err); | |
319 | goto fail; | |
320 | } | |
8dfba279 KW |
321 | |
322 | s->commit_top_bs = commit_top_bs; | |
323 | bdrv_unref(commit_top_bs); | |
747ff602 | 324 | |
3e4c5122 AG |
325 | /* Block all nodes between top and base, because they will |
326 | * disappear from the chain after this operation. */ | |
327 | assert(bdrv_chain_contains(top, base)); | |
8dfba279 KW |
328 | for (iter = top; iter != base; iter = backing_bs(iter)) { |
329 | /* XXX BLK_PERM_WRITE needs to be allowed so we don't block ourselves | |
330 | * at s->base (if writes are blocked for a node, they are also blocked | |
331 | * for its backing file). The other options would be a second filter | |
332 | * driver above s->base. */ | |
333 | ret = block_job_add_bdrv(&s->common, "intermediate node", iter, 0, | |
334 | BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE, | |
335 | errp); | |
336 | if (ret < 0) { | |
337 | goto fail; | |
338 | } | |
3e4c5122 | 339 | } |
8dfba279 | 340 | |
df827336 AG |
341 | if (bdrv_freeze_backing_chain(commit_top_bs, base, errp) < 0) { |
342 | goto fail; | |
343 | } | |
344 | s->chain_frozen = true; | |
345 | ||
8dfba279 KW |
346 | ret = block_job_add_bdrv(&s->common, "base", base, 0, BLK_PERM_ALL, errp); |
347 | if (ret < 0) { | |
348 | goto fail; | |
349 | } | |
350 | ||
8dfba279 KW |
351 | s->base = blk_new(BLK_PERM_CONSISTENT_READ |
352 | | BLK_PERM_WRITE | |
353 | | BLK_PERM_RESIZE, | |
354 | BLK_PERM_CONSISTENT_READ | |
355 | | BLK_PERM_GRAPH_MOD | |
356 | | BLK_PERM_WRITE_UNCHANGED); | |
d7086422 KW |
357 | ret = blk_insert_bs(s->base, base, errp); |
358 | if (ret < 0) { | |
359 | goto fail; | |
360 | } | |
22dffcbe | 361 | s->base_bs = base; |
4653456a | 362 | |
8dfba279 | 363 | /* Required permissions are already taken with block_job_add_bdrv() */ |
6d0eb64d | 364 | s->top = blk_new(0, BLK_PERM_ALL); |
b247767a | 365 | ret = blk_insert_bs(s->top, top, errp); |
d7086422 KW |
366 | if (ret < 0) { |
367 | goto fail; | |
368 | } | |
4653456a | 369 | |
54e26900 | 370 | s->backing_file_str = g_strdup(backing_file_str); |
747ff602 | 371 | s->on_error = on_error; |
747ff602 | 372 | |
5ccac6f1 | 373 | trace_commit_start(bs, base, top, s); |
da01ff7f | 374 | job_start(&s->common.job); |
d7086422 KW |
375 | return; |
376 | ||
377 | fail: | |
df827336 AG |
378 | if (s->chain_frozen) { |
379 | bdrv_unfreeze_backing_chain(commit_top_bs, base); | |
380 | } | |
d7086422 KW |
381 | if (s->base) { |
382 | blk_unref(s->base); | |
383 | } | |
384 | if (s->top) { | |
385 | blk_unref(s->top); | |
386 | } | |
2468eed3 AG |
387 | job_early_fail(&s->common.job); |
388 | /* commit_top_bs has to be replaced after deleting the block job, | |
389 | * otherwise this would fail because of lack of permissions. */ | |
8dfba279 | 390 | if (commit_top_bs) { |
bde70715 | 391 | bdrv_replace_node(commit_top_bs, top, &error_abort); |
8dfba279 | 392 | } |
747ff602 | 393 | } |
83fd6dd3 KW |
394 | |
395 | ||
d6a644bb | 396 | #define COMMIT_BUF_SIZE (2048 * BDRV_SECTOR_SIZE) |
83fd6dd3 KW |
397 | |
398 | /* commit COW file into the raw image */ | |
399 | int bdrv_commit(BlockDriverState *bs) | |
400 | { | |
f8e2bd53 | 401 | BlockBackend *src, *backing; |
d3f06759 KW |
402 | BlockDriverState *backing_file_bs = NULL; |
403 | BlockDriverState *commit_top_bs = NULL; | |
83fd6dd3 | 404 | BlockDriver *drv = bs->drv; |
d6a644bb | 405 | int64_t offset, length, backing_length; |
c742a364 | 406 | int ro; |
d6a644bb | 407 | int64_t n; |
83fd6dd3 KW |
408 | int ret = 0; |
409 | uint8_t *buf = NULL; | |
d3f06759 | 410 | Error *local_err = NULL; |
83fd6dd3 KW |
411 | |
412 | if (!drv) | |
413 | return -ENOMEDIUM; | |
414 | ||
415 | if (!bs->backing) { | |
416 | return -ENOTSUP; | |
417 | } | |
418 | ||
419 | if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_COMMIT_SOURCE, NULL) || | |
420 | bdrv_op_is_blocked(bs->backing->bs, BLOCK_OP_TYPE_COMMIT_TARGET, NULL)) { | |
421 | return -EBUSY; | |
422 | } | |
423 | ||
424 | ro = bs->backing->bs->read_only; | |
83fd6dd3 KW |
425 | |
426 | if (ro) { | |
c742a364 | 427 | if (bdrv_reopen_set_read_only(bs->backing->bs, false, NULL)) { |
83fd6dd3 KW |
428 | return -EACCES; |
429 | } | |
430 | } | |
431 | ||
d3f06759 KW |
432 | src = blk_new(BLK_PERM_CONSISTENT_READ, BLK_PERM_ALL); |
433 | backing = blk_new(BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL); | |
d7086422 | 434 | |
d3f06759 | 435 | ret = blk_insert_bs(src, bs, &local_err); |
d7086422 | 436 | if (ret < 0) { |
d3f06759 KW |
437 | error_report_err(local_err); |
438 | goto ro_cleanup; | |
439 | } | |
440 | ||
441 | /* Insert commit_top block node above backing, so we can write to it */ | |
442 | backing_file_bs = backing_bs(bs); | |
443 | ||
444 | commit_top_bs = bdrv_new_open_driver(&bdrv_commit_top, NULL, BDRV_O_RDWR, | |
445 | &local_err); | |
446 | if (commit_top_bs == NULL) { | |
447 | error_report_err(local_err); | |
d7086422 KW |
448 | goto ro_cleanup; |
449 | } | |
02be4aeb | 450 | bdrv_set_aio_context(commit_top_bs, bdrv_get_aio_context(backing_file_bs)); |
d7086422 | 451 | |
12fa4af6 KW |
452 | bdrv_set_backing_hd(commit_top_bs, backing_file_bs, &error_abort); |
453 | bdrv_set_backing_hd(bs, commit_top_bs, &error_abort); | |
d3f06759 KW |
454 | |
455 | ret = blk_insert_bs(backing, backing_file_bs, &local_err); | |
d7086422 | 456 | if (ret < 0) { |
d3f06759 | 457 | error_report_err(local_err); |
d7086422 KW |
458 | goto ro_cleanup; |
459 | } | |
f8e2bd53 KW |
460 | |
461 | length = blk_getlength(src); | |
83fd6dd3 KW |
462 | if (length < 0) { |
463 | ret = length; | |
464 | goto ro_cleanup; | |
465 | } | |
466 | ||
f8e2bd53 | 467 | backing_length = blk_getlength(backing); |
83fd6dd3 KW |
468 | if (backing_length < 0) { |
469 | ret = backing_length; | |
470 | goto ro_cleanup; | |
471 | } | |
472 | ||
473 | /* If our top snapshot is larger than the backing file image, | |
474 | * grow the backing file image if possible. If not possible, | |
475 | * we must return an error */ | |
476 | if (length > backing_length) { | |
3a691c50 | 477 | ret = blk_truncate(backing, length, PREALLOC_MODE_OFF, &local_err); |
83fd6dd3 | 478 | if (ret < 0) { |
ed3d2ec9 | 479 | error_report_err(local_err); |
83fd6dd3 KW |
480 | goto ro_cleanup; |
481 | } | |
482 | } | |
483 | ||
f8e2bd53 KW |
484 | /* blk_try_blockalign() for src will choose an alignment that works for |
485 | * backing as well, so no need to compare the alignment manually. */ | |
d6a644bb | 486 | buf = blk_try_blockalign(src, COMMIT_BUF_SIZE); |
83fd6dd3 KW |
487 | if (buf == NULL) { |
488 | ret = -ENOMEM; | |
489 | goto ro_cleanup; | |
490 | } | |
491 | ||
d6a644bb EB |
492 | for (offset = 0; offset < length; offset += n) { |
493 | ret = bdrv_is_allocated(bs, offset, COMMIT_BUF_SIZE, &n); | |
83fd6dd3 KW |
494 | if (ret < 0) { |
495 | goto ro_cleanup; | |
496 | } | |
497 | if (ret) { | |
d6a644bb | 498 | ret = blk_pread(src, offset, buf, n); |
83fd6dd3 KW |
499 | if (ret < 0) { |
500 | goto ro_cleanup; | |
501 | } | |
502 | ||
d6a644bb | 503 | ret = blk_pwrite(backing, offset, buf, n, 0); |
83fd6dd3 KW |
504 | if (ret < 0) { |
505 | goto ro_cleanup; | |
506 | } | |
507 | } | |
508 | } | |
509 | ||
510 | if (drv->bdrv_make_empty) { | |
511 | ret = drv->bdrv_make_empty(bs); | |
512 | if (ret < 0) { | |
513 | goto ro_cleanup; | |
514 | } | |
f8e2bd53 | 515 | blk_flush(src); |
83fd6dd3 KW |
516 | } |
517 | ||
518 | /* | |
519 | * Make sure all data we wrote to the backing device is actually | |
520 | * stable on disk. | |
521 | */ | |
f8e2bd53 | 522 | blk_flush(backing); |
83fd6dd3 KW |
523 | |
524 | ret = 0; | |
525 | ro_cleanup: | |
526 | qemu_vfree(buf); | |
527 | ||
f8e2bd53 | 528 | blk_unref(backing); |
d3f06759 | 529 | if (backing_file_bs) { |
12fa4af6 | 530 | bdrv_set_backing_hd(bs, backing_file_bs, &error_abort); |
d3f06759 KW |
531 | } |
532 | bdrv_unref(commit_top_bs); | |
533 | blk_unref(src); | |
f8e2bd53 | 534 | |
83fd6dd3 KW |
535 | if (ro) { |
536 | /* ignoring error return here */ | |
c742a364 | 537 | bdrv_reopen_set_read_only(bs->backing->bs, true, NULL); |
83fd6dd3 KW |
538 | } |
539 | ||
540 | return ret; | |
541 | } |