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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; | |
92aa5c6d | 39 | BlockdevOnError on_error; |
747ff602 | 40 | int base_flags; |
54e26900 | 41 | char *backing_file_str; |
747ff602 JC |
42 | } CommitBlockJob; |
43 | ||
4653456a | 44 | static int coroutine_fn commit_populate(BlockBackend *bs, BlockBackend *base, |
d8a98584 | 45 | int64_t offset, uint64_t bytes, |
747ff602 JC |
46 | void *buf) |
47 | { | |
48 | int ret = 0; | |
4653456a KW |
49 | QEMUIOVector qiov; |
50 | struct iovec iov = { | |
51 | .iov_base = buf, | |
d8a98584 | 52 | .iov_len = bytes, |
4653456a | 53 | }; |
747ff602 | 54 | |
d8a98584 | 55 | assert(bytes < SIZE_MAX); |
4653456a KW |
56 | qemu_iovec_init_external(&qiov, &iov, 1); |
57 | ||
d8a98584 | 58 | ret = blk_co_preadv(bs, offset, qiov.size, &qiov, 0); |
4653456a | 59 | if (ret < 0) { |
747ff602 JC |
60 | return ret; |
61 | } | |
62 | ||
d8a98584 | 63 | ret = blk_co_pwritev(base, offset, qiov.size, &qiov, 0); |
4653456a | 64 | if (ret < 0) { |
747ff602 JC |
65 | return ret; |
66 | } | |
67 | ||
68 | return 0; | |
69 | } | |
70 | ||
9e85cd5c SH |
71 | typedef struct { |
72 | int ret; | |
73 | } CommitCompleteData; | |
74 | ||
1908a559 | 75 | static void commit_complete(Job *job, void *opaque) |
747ff602 | 76 | { |
1908a559 KW |
77 | CommitBlockJob *s = container_of(job, CommitBlockJob, common.job); |
78 | BlockJob *bjob = &s->common; | |
9e85cd5c | 79 | CommitCompleteData *data = opaque; |
4653456a KW |
80 | BlockDriverState *top = blk_bs(s->top); |
81 | BlockDriverState *base = blk_bs(s->base); | |
bde70715 | 82 | BlockDriverState *commit_top_bs = s->commit_top_bs; |
9e85cd5c | 83 | int ret = data->ret; |
8dfba279 KW |
84 | bool remove_commit_top_bs = false; |
85 | ||
bde70715 | 86 | /* Make sure commit_top_bs and top stay around until bdrv_replace_node() */ |
19ebd13e | 87 | bdrv_ref(top); |
bde70715 | 88 | bdrv_ref(commit_top_bs); |
19ebd13e | 89 | |
8dfba279 KW |
90 | /* Remove base node parent that still uses BLK_PERM_WRITE/RESIZE before |
91 | * the normal backing chain can be restored. */ | |
92 | blk_unref(s->base); | |
9e85cd5c | 93 | |
1908a559 | 94 | if (!job_is_cancelled(job) && ret == 0) { |
9e85cd5c | 95 | /* success */ |
bde70715 | 96 | ret = bdrv_drop_intermediate(s->commit_top_bs, base, |
8dfba279 | 97 | s->backing_file_str); |
bde70715 | 98 | } else { |
8dfba279 KW |
99 | /* XXX Can (or should) we somehow keep 'consistent read' blocked even |
100 | * after the failed/cancelled commit job is gone? If we already wrote | |
101 | * something to base, the intermediate images aren't valid any more. */ | |
102 | remove_commit_top_bs = true; | |
9e85cd5c SH |
103 | } |
104 | ||
105 | /* restore base open flags here if appropriate (e.g., change the base back | |
106 | * to r/o). These reopens do not need to be atomic, since we won't abort | |
107 | * even on failure here */ | |
108 | if (s->base_flags != bdrv_get_flags(base)) { | |
109 | bdrv_reopen(base, s->base_flags, NULL); | |
110 | } | |
9e85cd5c | 111 | g_free(s->backing_file_str); |
4653456a | 112 | blk_unref(s->top); |
4f78a16f KW |
113 | |
114 | /* If there is more than one reference to the job (e.g. if called from | |
115 | * block_job_finish_sync()), block_job_completed() won't free it and | |
116 | * therefore the blockers on the intermediate nodes remain. This would | |
117 | * cause bdrv_set_backing_hd() to fail. */ | |
1908a559 | 118 | block_job_remove_all_bdrv(bjob); |
4f78a16f | 119 | |
9e85cd5c SH |
120 | block_job_completed(&s->common, ret); |
121 | g_free(data); | |
8dfba279 KW |
122 | |
123 | /* If bdrv_drop_intermediate() didn't already do that, remove the commit | |
124 | * filter driver from the backing chain. Do this as the final step so that | |
125 | * the 'consistent read' permission can be granted. */ | |
126 | if (remove_commit_top_bs) { | |
bde70715 KW |
127 | bdrv_child_try_set_perm(commit_top_bs->backing, 0, BLK_PERM_ALL, |
128 | &error_abort); | |
129 | bdrv_replace_node(commit_top_bs, backing_bs(commit_top_bs), | |
130 | &error_abort); | |
8dfba279 | 131 | } |
19ebd13e | 132 | |
bde70715 | 133 | bdrv_unref(commit_top_bs); |
19ebd13e | 134 | bdrv_unref(top); |
9e85cd5c SH |
135 | } |
136 | ||
137 | static void coroutine_fn commit_run(void *opaque) | |
138 | { | |
139 | CommitBlockJob *s = opaque; | |
140 | CommitCompleteData *data; | |
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 | } |
05df8a6a | 153 | block_job_progress_set_remaining(&s->common, 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 */ | |
05df8a6a | 199 | block_job_progress_update(&s->common, 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 | ||
9e85cd5c SH |
213 | data = g_malloc(sizeof(*data)); |
214 | data->ret = ret; | |
1908a559 | 215 | job_defer_to_main_loop(&s->common.job, commit_complete, data); |
747ff602 JC |
216 | } |
217 | ||
3fc4b10a | 218 | static const BlockJobDriver commit_job_driver = { |
33e9e9bd KW |
219 | .job_driver = { |
220 | .instance_size = sizeof(CommitBlockJob), | |
252291ea | 221 | .job_type = JOB_TYPE_COMMIT, |
80fa2c75 | 222 | .free = block_job_free, |
b15de828 | 223 | .user_resume = block_job_user_resume, |
da01ff7f | 224 | .start = commit_run, |
33e9e9bd | 225 | }, |
747ff602 JC |
226 | }; |
227 | ||
8dfba279 KW |
228 | static int coroutine_fn bdrv_commit_top_preadv(BlockDriverState *bs, |
229 | uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags) | |
230 | { | |
231 | return bdrv_co_preadv(bs->backing, offset, bytes, qiov, flags); | |
232 | } | |
233 | ||
dcbf37ce KW |
234 | static void bdrv_commit_top_refresh_filename(BlockDriverState *bs, QDict *opts) |
235 | { | |
236 | bdrv_refresh_filename(bs->backing->bs); | |
237 | pstrcpy(bs->exact_filename, sizeof(bs->exact_filename), | |
238 | bs->backing->bs->filename); | |
239 | } | |
91965658 | 240 | |
8dfba279 KW |
241 | static void bdrv_commit_top_close(BlockDriverState *bs) |
242 | { | |
243 | } | |
244 | ||
245 | static void bdrv_commit_top_child_perm(BlockDriverState *bs, BdrvChild *c, | |
246 | const BdrvChildRole *role, | |
e0995dc3 | 247 | BlockReopenQueue *reopen_queue, |
8dfba279 KW |
248 | uint64_t perm, uint64_t shared, |
249 | uint64_t *nperm, uint64_t *nshared) | |
250 | { | |
251 | *nperm = 0; | |
252 | *nshared = BLK_PERM_ALL; | |
253 | } | |
254 | ||
255 | /* Dummy node that provides consistent read to its users without requiring it | |
256 | * from its backing file and that allows writes on the backing file chain. */ | |
257 | static BlockDriver bdrv_commit_top = { | |
91965658 KW |
258 | .format_name = "commit_top", |
259 | .bdrv_co_preadv = bdrv_commit_top_preadv, | |
3e4d0e72 | 260 | .bdrv_co_block_status = bdrv_co_block_status_from_backing, |
dcbf37ce | 261 | .bdrv_refresh_filename = bdrv_commit_top_refresh_filename, |
91965658 KW |
262 | .bdrv_close = bdrv_commit_top_close, |
263 | .bdrv_child_perm = bdrv_commit_top_child_perm, | |
8dfba279 KW |
264 | }; |
265 | ||
fd62c609 AG |
266 | void commit_start(const char *job_id, BlockDriverState *bs, |
267 | BlockDriverState *base, BlockDriverState *top, int64_t speed, | |
8254b6d9 | 268 | BlockdevOnError on_error, const char *backing_file_str, |
0db832f4 | 269 | const char *filter_node_name, Error **errp) |
747ff602 JC |
270 | { |
271 | CommitBlockJob *s; | |
747ff602 | 272 | int orig_base_flags; |
3e4c5122 | 273 | BlockDriverState *iter; |
8dfba279 | 274 | BlockDriverState *commit_top_bs = NULL; |
747ff602 | 275 | Error *local_err = NULL; |
d7086422 | 276 | int ret; |
747ff602 | 277 | |
18da7f94 | 278 | assert(top != bs); |
747ff602 JC |
279 | if (top == base) { |
280 | error_setg(errp, "Invalid files for merge: top and base are the same"); | |
281 | return; | |
282 | } | |
283 | ||
75859b94 | 284 | s = block_job_create(job_id, &commit_job_driver, NULL, bs, 0, BLK_PERM_ALL, |
bb02b65c | 285 | speed, JOB_DEFAULT, NULL, NULL, errp); |
834fe28d AG |
286 | if (!s) { |
287 | return; | |
288 | } | |
289 | ||
bde70715 KW |
290 | /* convert base to r/w, if necessary */ |
291 | orig_base_flags = bdrv_get_flags(base); | |
3db2bd55 | 292 | if (!(orig_base_flags & BDRV_O_RDWR)) { |
44487eb9 | 293 | bdrv_reopen(base, orig_base_flags | BDRV_O_RDWR, &local_err); |
747ff602 JC |
294 | if (local_err != NULL) { |
295 | error_propagate(errp, local_err); | |
d7086422 | 296 | goto fail; |
747ff602 JC |
297 | } |
298 | } | |
299 | ||
8dfba279 KW |
300 | /* Insert commit_top block node above top, so we can block consistent read |
301 | * on the backing chain below it */ | |
0db832f4 KW |
302 | commit_top_bs = bdrv_new_open_driver(&bdrv_commit_top, filter_node_name, 0, |
303 | errp); | |
8dfba279 KW |
304 | if (commit_top_bs == NULL) { |
305 | goto fail; | |
306 | } | |
d3c8c674 KW |
307 | if (!filter_node_name) { |
308 | commit_top_bs->implicit = true; | |
309 | } | |
0d0676a1 | 310 | commit_top_bs->total_sectors = top->total_sectors; |
02be4aeb | 311 | bdrv_set_aio_context(commit_top_bs, bdrv_get_aio_context(top)); |
8dfba279 | 312 | |
b69f00dd FZ |
313 | bdrv_set_backing_hd(commit_top_bs, top, &local_err); |
314 | if (local_err) { | |
315 | bdrv_unref(commit_top_bs); | |
316 | commit_top_bs = NULL; | |
317 | error_propagate(errp, local_err); | |
318 | goto fail; | |
319 | } | |
61f09cea | 320 | bdrv_replace_node(top, commit_top_bs, &local_err); |
b69f00dd FZ |
321 | if (local_err) { |
322 | bdrv_unref(commit_top_bs); | |
323 | commit_top_bs = NULL; | |
324 | error_propagate(errp, local_err); | |
325 | goto fail; | |
326 | } | |
8dfba279 KW |
327 | |
328 | s->commit_top_bs = commit_top_bs; | |
329 | bdrv_unref(commit_top_bs); | |
747ff602 | 330 | |
3e4c5122 AG |
331 | /* Block all nodes between top and base, because they will |
332 | * disappear from the chain after this operation. */ | |
333 | assert(bdrv_chain_contains(top, base)); | |
8dfba279 KW |
334 | for (iter = top; iter != base; iter = backing_bs(iter)) { |
335 | /* XXX BLK_PERM_WRITE needs to be allowed so we don't block ourselves | |
336 | * at s->base (if writes are blocked for a node, they are also blocked | |
337 | * for its backing file). The other options would be a second filter | |
338 | * driver above s->base. */ | |
339 | ret = block_job_add_bdrv(&s->common, "intermediate node", iter, 0, | |
340 | BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE, | |
341 | errp); | |
342 | if (ret < 0) { | |
343 | goto fail; | |
344 | } | |
3e4c5122 | 345 | } |
8dfba279 KW |
346 | |
347 | ret = block_job_add_bdrv(&s->common, "base", base, 0, BLK_PERM_ALL, errp); | |
348 | if (ret < 0) { | |
349 | goto fail; | |
350 | } | |
351 | ||
8dfba279 KW |
352 | s->base = blk_new(BLK_PERM_CONSISTENT_READ |
353 | | BLK_PERM_WRITE | |
354 | | BLK_PERM_RESIZE, | |
355 | BLK_PERM_CONSISTENT_READ | |
356 | | BLK_PERM_GRAPH_MOD | |
357 | | BLK_PERM_WRITE_UNCHANGED); | |
d7086422 KW |
358 | ret = blk_insert_bs(s->base, base, errp); |
359 | if (ret < 0) { | |
360 | goto fail; | |
361 | } | |
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 | |
bde70715 | 370 | s->base_flags = orig_base_flags; |
54e26900 | 371 | s->backing_file_str = g_strdup(backing_file_str); |
747ff602 | 372 | s->on_error = on_error; |
747ff602 | 373 | |
5ccac6f1 | 374 | trace_commit_start(bs, base, top, s); |
da01ff7f | 375 | job_start(&s->common.job); |
d7086422 KW |
376 | return; |
377 | ||
378 | fail: | |
379 | if (s->base) { | |
380 | blk_unref(s->base); | |
381 | } | |
382 | if (s->top) { | |
383 | blk_unref(s->top); | |
384 | } | |
8dfba279 | 385 | if (commit_top_bs) { |
bde70715 | 386 | bdrv_replace_node(commit_top_bs, top, &error_abort); |
8dfba279 | 387 | } |
4ad35181 | 388 | job_early_fail(&s->common.job); |
747ff602 | 389 | } |
83fd6dd3 KW |
390 | |
391 | ||
d6a644bb | 392 | #define COMMIT_BUF_SIZE (2048 * BDRV_SECTOR_SIZE) |
83fd6dd3 KW |
393 | |
394 | /* commit COW file into the raw image */ | |
395 | int bdrv_commit(BlockDriverState *bs) | |
396 | { | |
f8e2bd53 | 397 | BlockBackend *src, *backing; |
d3f06759 KW |
398 | BlockDriverState *backing_file_bs = NULL; |
399 | BlockDriverState *commit_top_bs = NULL; | |
83fd6dd3 | 400 | BlockDriver *drv = bs->drv; |
d6a644bb EB |
401 | int64_t offset, length, backing_length; |
402 | int ro, open_flags; | |
403 | int64_t n; | |
83fd6dd3 KW |
404 | int ret = 0; |
405 | uint8_t *buf = NULL; | |
d3f06759 | 406 | Error *local_err = NULL; |
83fd6dd3 KW |
407 | |
408 | if (!drv) | |
409 | return -ENOMEDIUM; | |
410 | ||
411 | if (!bs->backing) { | |
412 | return -ENOTSUP; | |
413 | } | |
414 | ||
415 | if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_COMMIT_SOURCE, NULL) || | |
416 | bdrv_op_is_blocked(bs->backing->bs, BLOCK_OP_TYPE_COMMIT_TARGET, NULL)) { | |
417 | return -EBUSY; | |
418 | } | |
419 | ||
420 | ro = bs->backing->bs->read_only; | |
421 | open_flags = bs->backing->bs->open_flags; | |
422 | ||
423 | if (ro) { | |
424 | if (bdrv_reopen(bs->backing->bs, open_flags | BDRV_O_RDWR, NULL)) { | |
425 | return -EACCES; | |
426 | } | |
427 | } | |
428 | ||
d3f06759 KW |
429 | src = blk_new(BLK_PERM_CONSISTENT_READ, BLK_PERM_ALL); |
430 | backing = blk_new(BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL); | |
d7086422 | 431 | |
d3f06759 | 432 | ret = blk_insert_bs(src, bs, &local_err); |
d7086422 | 433 | if (ret < 0) { |
d3f06759 KW |
434 | error_report_err(local_err); |
435 | goto ro_cleanup; | |
436 | } | |
437 | ||
438 | /* Insert commit_top block node above backing, so we can write to it */ | |
439 | backing_file_bs = backing_bs(bs); | |
440 | ||
441 | commit_top_bs = bdrv_new_open_driver(&bdrv_commit_top, NULL, BDRV_O_RDWR, | |
442 | &local_err); | |
443 | if (commit_top_bs == NULL) { | |
444 | error_report_err(local_err); | |
d7086422 KW |
445 | goto ro_cleanup; |
446 | } | |
02be4aeb | 447 | bdrv_set_aio_context(commit_top_bs, bdrv_get_aio_context(backing_file_bs)); |
d7086422 | 448 | |
12fa4af6 KW |
449 | bdrv_set_backing_hd(commit_top_bs, backing_file_bs, &error_abort); |
450 | bdrv_set_backing_hd(bs, commit_top_bs, &error_abort); | |
d3f06759 KW |
451 | |
452 | ret = blk_insert_bs(backing, backing_file_bs, &local_err); | |
d7086422 | 453 | if (ret < 0) { |
d3f06759 | 454 | error_report_err(local_err); |
d7086422 KW |
455 | goto ro_cleanup; |
456 | } | |
f8e2bd53 KW |
457 | |
458 | length = blk_getlength(src); | |
83fd6dd3 KW |
459 | if (length < 0) { |
460 | ret = length; | |
461 | goto ro_cleanup; | |
462 | } | |
463 | ||
f8e2bd53 | 464 | backing_length = blk_getlength(backing); |
83fd6dd3 KW |
465 | if (backing_length < 0) { |
466 | ret = backing_length; | |
467 | goto ro_cleanup; | |
468 | } | |
469 | ||
470 | /* If our top snapshot is larger than the backing file image, | |
471 | * grow the backing file image if possible. If not possible, | |
472 | * we must return an error */ | |
473 | if (length > backing_length) { | |
3a691c50 | 474 | ret = blk_truncate(backing, length, PREALLOC_MODE_OFF, &local_err); |
83fd6dd3 | 475 | if (ret < 0) { |
ed3d2ec9 | 476 | error_report_err(local_err); |
83fd6dd3 KW |
477 | goto ro_cleanup; |
478 | } | |
479 | } | |
480 | ||
f8e2bd53 KW |
481 | /* blk_try_blockalign() for src will choose an alignment that works for |
482 | * backing as well, so no need to compare the alignment manually. */ | |
d6a644bb | 483 | buf = blk_try_blockalign(src, COMMIT_BUF_SIZE); |
83fd6dd3 KW |
484 | if (buf == NULL) { |
485 | ret = -ENOMEM; | |
486 | goto ro_cleanup; | |
487 | } | |
488 | ||
d6a644bb EB |
489 | for (offset = 0; offset < length; offset += n) { |
490 | ret = bdrv_is_allocated(bs, offset, COMMIT_BUF_SIZE, &n); | |
83fd6dd3 KW |
491 | if (ret < 0) { |
492 | goto ro_cleanup; | |
493 | } | |
494 | if (ret) { | |
d6a644bb | 495 | ret = blk_pread(src, offset, buf, n); |
83fd6dd3 KW |
496 | if (ret < 0) { |
497 | goto ro_cleanup; | |
498 | } | |
499 | ||
d6a644bb | 500 | ret = blk_pwrite(backing, offset, buf, n, 0); |
83fd6dd3 KW |
501 | if (ret < 0) { |
502 | goto ro_cleanup; | |
503 | } | |
504 | } | |
505 | } | |
506 | ||
507 | if (drv->bdrv_make_empty) { | |
508 | ret = drv->bdrv_make_empty(bs); | |
509 | if (ret < 0) { | |
510 | goto ro_cleanup; | |
511 | } | |
f8e2bd53 | 512 | blk_flush(src); |
83fd6dd3 KW |
513 | } |
514 | ||
515 | /* | |
516 | * Make sure all data we wrote to the backing device is actually | |
517 | * stable on disk. | |
518 | */ | |
f8e2bd53 | 519 | blk_flush(backing); |
83fd6dd3 KW |
520 | |
521 | ret = 0; | |
522 | ro_cleanup: | |
523 | qemu_vfree(buf); | |
524 | ||
f8e2bd53 | 525 | blk_unref(backing); |
d3f06759 | 526 | if (backing_file_bs) { |
12fa4af6 | 527 | bdrv_set_backing_hd(bs, backing_file_bs, &error_abort); |
d3f06759 KW |
528 | } |
529 | bdrv_unref(commit_top_bs); | |
530 | blk_unref(src); | |
f8e2bd53 | 531 | |
83fd6dd3 KW |
532 | if (ro) { |
533 | /* ignoring error return here */ | |
534 | bdrv_reopen(bs->backing->bs, open_flags & ~BDRV_O_RDWR, NULL); | |
535 | } | |
536 | ||
537 | return ret; | |
538 | } |