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15#include "qemu/osdep.h"
16#include "qemu/cutils.h"
17#include "trace.h"
18#include "block/block_int.h"
19#include "block/blockjob_int.h"
20#include "qapi/error.h"
21#include "qapi/qmp/qerror.h"
22#include "qemu/ratelimit.h"
23#include "sysemu/block-backend.h"
24
25enum {
26
27
28
29
30
31 COMMIT_BUFFER_SIZE = 512 * 1024,
32};
33
34typedef struct CommitBlockJob {
35 BlockJob common;
36 BlockDriverState *commit_top_bs;
37 BlockBackend *top;
38 BlockBackend *base;
39 BlockdevOnError on_error;
40 int base_flags;
41 char *backing_file_str;
42} CommitBlockJob;
43
44static int coroutine_fn commit_populate(BlockBackend *bs, BlockBackend *base,
45 int64_t offset, uint64_t bytes,
46 void *buf)
47{
48 int ret = 0;
49 QEMUIOVector qiov;
50 struct iovec iov = {
51 .iov_base = buf,
52 .iov_len = bytes,
53 };
54
55 assert(bytes < SIZE_MAX);
56 qemu_iovec_init_external(&qiov, &iov, 1);
57
58 ret = blk_co_preadv(bs, offset, qiov.size, &qiov, 0);
59 if (ret < 0) {
60 return ret;
61 }
62
63 ret = blk_co_pwritev(base, offset, qiov.size, &qiov, 0);
64 if (ret < 0) {
65 return ret;
66 }
67
68 return 0;
69}
70
71typedef struct {
72 int ret;
73} CommitCompleteData;
74
75static void commit_complete(Job *job, void *opaque)
76{
77 CommitBlockJob *s = container_of(job, CommitBlockJob, common.job);
78 BlockJob *bjob = &s->common;
79 CommitCompleteData *data = opaque;
80 BlockDriverState *top = blk_bs(s->top);
81 BlockDriverState *base = blk_bs(s->base);
82 BlockDriverState *commit_top_bs = s->commit_top_bs;
83 int ret = data->ret;
84 bool remove_commit_top_bs = false;
85
86
87 bdrv_ref(top);
88 bdrv_ref(commit_top_bs);
89
90
91
92 blk_unref(s->base);
93
94 if (!job_is_cancelled(job) && ret == 0) {
95
96 ret = bdrv_drop_intermediate(s->commit_top_bs, base,
97 s->backing_file_str);
98 } else {
99
100
101
102 remove_commit_top_bs = true;
103 }
104
105
106
107
108 if (s->base_flags != bdrv_get_flags(base)) {
109 bdrv_reopen(base, s->base_flags, NULL);
110 }
111 g_free(s->backing_file_str);
112 blk_unref(s->top);
113
114
115
116
117
118 block_job_remove_all_bdrv(bjob);
119
120 job_completed(job, ret, NULL);
121 g_free(data);
122
123
124
125
126 if (remove_commit_top_bs) {
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);
131 }
132
133 bdrv_unref(commit_top_bs);
134 bdrv_unref(top);
135}
136
137static void coroutine_fn commit_run(void *opaque)
138{
139 CommitBlockJob *s = opaque;
140 CommitCompleteData *data;
141 int64_t offset;
142 uint64_t delay_ns = 0;
143 int ret = 0;
144 int64_t n = 0;
145 void *buf = NULL;
146 int bytes_written = 0;
147 int64_t len, base_len;
148
149 ret = len = blk_getlength(s->top);
150 if (len < 0) {
151 goto out;
152 }
153 job_progress_set_remaining(&s->common.job, len);
154
155 ret = base_len = blk_getlength(s->base);
156 if (base_len < 0) {
157 goto out;
158 }
159
160 if (base_len < len) {
161 ret = blk_truncate(s->base, len, PREALLOC_MODE_OFF, NULL);
162 if (ret) {
163 goto out;
164 }
165 }
166
167 buf = blk_blockalign(s->top, COMMIT_BUFFER_SIZE);
168
169 for (offset = 0; offset < len; offset += n) {
170 bool copy;
171
172
173
174
175 job_sleep_ns(&s->common.job, delay_ns);
176 if (job_is_cancelled(&s->common.job)) {
177 break;
178 }
179
180 ret = bdrv_is_allocated_above(blk_bs(s->top), blk_bs(s->base),
181 offset, COMMIT_BUFFER_SIZE, &n);
182 copy = (ret == 1);
183 trace_commit_one_iteration(s, offset, n, ret);
184 if (copy) {
185 ret = commit_populate(s->top, s->base, offset, n, buf);
186 bytes_written += n;
187 }
188 if (ret < 0) {
189 BlockErrorAction action =
190 block_job_error_action(&s->common, false, s->on_error, -ret);
191 if (action == BLOCK_ERROR_ACTION_REPORT) {
192 goto out;
193 } else {
194 n = 0;
195 continue;
196 }
197 }
198
199 job_progress_update(&s->common.job, n);
200
201 if (copy) {
202 delay_ns = block_job_ratelimit_get_delay(&s->common, n);
203 } else {
204 delay_ns = 0;
205 }
206 }
207
208 ret = 0;
209
210out:
211 qemu_vfree(buf);
212
213 data = g_malloc(sizeof(*data));
214 data->ret = ret;
215 job_defer_to_main_loop(&s->common.job, commit_complete, data);
216}
217
218static const BlockJobDriver commit_job_driver = {
219 .job_driver = {
220 .instance_size = sizeof(CommitBlockJob),
221 .job_type = JOB_TYPE_COMMIT,
222 .free = block_job_free,
223 .user_resume = block_job_user_resume,
224 .drain = block_job_drain,
225 .start = commit_run,
226 },
227};
228
229static int coroutine_fn bdrv_commit_top_preadv(BlockDriverState *bs,
230 uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags)
231{
232 return bdrv_co_preadv(bs->backing, offset, bytes, qiov, flags);
233}
234
235static void bdrv_commit_top_refresh_filename(BlockDriverState *bs, QDict *opts)
236{
237 bdrv_refresh_filename(bs->backing->bs);
238 pstrcpy(bs->exact_filename, sizeof(bs->exact_filename),
239 bs->backing->bs->filename);
240}
241
242static void bdrv_commit_top_close(BlockDriverState *bs)
243{
244}
245
246static void bdrv_commit_top_child_perm(BlockDriverState *bs, BdrvChild *c,
247 const BdrvChildRole *role,
248 BlockReopenQueue *reopen_queue,
249 uint64_t perm, uint64_t shared,
250 uint64_t *nperm, uint64_t *nshared)
251{
252 *nperm = 0;
253 *nshared = BLK_PERM_ALL;
254}
255
256
257
258static BlockDriver bdrv_commit_top = {
259 .format_name = "commit_top",
260 .bdrv_co_preadv = bdrv_commit_top_preadv,
261 .bdrv_co_block_status = bdrv_co_block_status_from_backing,
262 .bdrv_refresh_filename = bdrv_commit_top_refresh_filename,
263 .bdrv_close = bdrv_commit_top_close,
264 .bdrv_child_perm = bdrv_commit_top_child_perm,
265};
266
267void commit_start(const char *job_id, BlockDriverState *bs,
268 BlockDriverState *base, BlockDriverState *top, int64_t speed,
269 BlockdevOnError on_error, const char *backing_file_str,
270 const char *filter_node_name, Error **errp)
271{
272 CommitBlockJob *s;
273 int orig_base_flags;
274 BlockDriverState *iter;
275 BlockDriverState *commit_top_bs = NULL;
276 Error *local_err = NULL;
277 int ret;
278
279 assert(top != bs);
280 if (top == base) {
281 error_setg(errp, "Invalid files for merge: top and base are the same");
282 return;
283 }
284
285 s = block_job_create(job_id, &commit_job_driver, NULL, bs, 0, BLK_PERM_ALL,
286 speed, JOB_DEFAULT, NULL, NULL, errp);
287 if (!s) {
288 return;
289 }
290
291
292 orig_base_flags = bdrv_get_flags(base);
293 if (!(orig_base_flags & BDRV_O_RDWR)) {
294 bdrv_reopen(base, orig_base_flags | BDRV_O_RDWR, &local_err);
295 if (local_err != NULL) {
296 error_propagate(errp, local_err);
297 goto fail;
298 }
299 }
300
301
302
303 commit_top_bs = bdrv_new_open_driver(&bdrv_commit_top, filter_node_name, 0,
304 errp);
305 if (commit_top_bs == NULL) {
306 goto fail;
307 }
308 if (!filter_node_name) {
309 commit_top_bs->implicit = true;
310 }
311 commit_top_bs->total_sectors = top->total_sectors;
312 bdrv_set_aio_context(commit_top_bs, bdrv_get_aio_context(top));
313
314 bdrv_set_backing_hd(commit_top_bs, top, &local_err);
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 }
321 bdrv_replace_node(top, commit_top_bs, &local_err);
322 if (local_err) {
323 bdrv_unref(commit_top_bs);
324 commit_top_bs = NULL;
325 error_propagate(errp, local_err);
326 goto fail;
327 }
328
329 s->commit_top_bs = commit_top_bs;
330 bdrv_unref(commit_top_bs);
331
332
333
334 assert(bdrv_chain_contains(top, base));
335 for (iter = top; iter != base; iter = backing_bs(iter)) {
336
337
338
339
340 ret = block_job_add_bdrv(&s->common, "intermediate node", iter, 0,
341 BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE,
342 errp);
343 if (ret < 0) {
344 goto fail;
345 }
346 }
347
348 ret = block_job_add_bdrv(&s->common, "base", base, 0, BLK_PERM_ALL, errp);
349 if (ret < 0) {
350 goto fail;
351 }
352
353 s->base = blk_new(BLK_PERM_CONSISTENT_READ
354 | BLK_PERM_WRITE
355 | BLK_PERM_RESIZE,
356 BLK_PERM_CONSISTENT_READ
357 | BLK_PERM_GRAPH_MOD
358 | BLK_PERM_WRITE_UNCHANGED);
359 ret = blk_insert_bs(s->base, base, errp);
360 if (ret < 0) {
361 goto fail;
362 }
363
364
365 s->top = blk_new(0, BLK_PERM_ALL);
366 ret = blk_insert_bs(s->top, top, errp);
367 if (ret < 0) {
368 goto fail;
369 }
370
371 s->base_flags = orig_base_flags;
372 s->backing_file_str = g_strdup(backing_file_str);
373 s->on_error = on_error;
374
375 trace_commit_start(bs, base, top, s);
376 job_start(&s->common.job);
377 return;
378
379fail:
380 if (s->base) {
381 blk_unref(s->base);
382 }
383 if (s->top) {
384 blk_unref(s->top);
385 }
386 if (commit_top_bs) {
387 bdrv_replace_node(commit_top_bs, top, &error_abort);
388 }
389 job_early_fail(&s->common.job);
390}
391
392
393#define COMMIT_BUF_SIZE (2048 * BDRV_SECTOR_SIZE)
394
395
396int bdrv_commit(BlockDriverState *bs)
397{
398 BlockBackend *src, *backing;
399 BlockDriverState *backing_file_bs = NULL;
400 BlockDriverState *commit_top_bs = NULL;
401 BlockDriver *drv = bs->drv;
402 int64_t offset, length, backing_length;
403 int ro, open_flags;
404 int64_t n;
405 int ret = 0;
406 uint8_t *buf = NULL;
407 Error *local_err = NULL;
408
409 if (!drv)
410 return -ENOMEDIUM;
411
412 if (!bs->backing) {
413 return -ENOTSUP;
414 }
415
416 if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_COMMIT_SOURCE, NULL) ||
417 bdrv_op_is_blocked(bs->backing->bs, BLOCK_OP_TYPE_COMMIT_TARGET, NULL)) {
418 return -EBUSY;
419 }
420
421 ro = bs->backing->bs->read_only;
422 open_flags = bs->backing->bs->open_flags;
423
424 if (ro) {
425 if (bdrv_reopen(bs->backing->bs, open_flags | BDRV_O_RDWR, NULL)) {
426 return -EACCES;
427 }
428 }
429
430 src = blk_new(BLK_PERM_CONSISTENT_READ, BLK_PERM_ALL);
431 backing = blk_new(BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL);
432
433 ret = blk_insert_bs(src, bs, &local_err);
434 if (ret < 0) {
435 error_report_err(local_err);
436 goto ro_cleanup;
437 }
438
439
440 backing_file_bs = backing_bs(bs);
441
442 commit_top_bs = bdrv_new_open_driver(&bdrv_commit_top, NULL, BDRV_O_RDWR,
443 &local_err);
444 if (commit_top_bs == NULL) {
445 error_report_err(local_err);
446 goto ro_cleanup;
447 }
448 bdrv_set_aio_context(commit_top_bs, bdrv_get_aio_context(backing_file_bs));
449
450 bdrv_set_backing_hd(commit_top_bs, backing_file_bs, &error_abort);
451 bdrv_set_backing_hd(bs, commit_top_bs, &error_abort);
452
453 ret = blk_insert_bs(backing, backing_file_bs, &local_err);
454 if (ret < 0) {
455 error_report_err(local_err);
456 goto ro_cleanup;
457 }
458
459 length = blk_getlength(src);
460 if (length < 0) {
461 ret = length;
462 goto ro_cleanup;
463 }
464
465 backing_length = blk_getlength(backing);
466 if (backing_length < 0) {
467 ret = backing_length;
468 goto ro_cleanup;
469 }
470
471
472
473
474 if (length > backing_length) {
475 ret = blk_truncate(backing, length, PREALLOC_MODE_OFF, &local_err);
476 if (ret < 0) {
477 error_report_err(local_err);
478 goto ro_cleanup;
479 }
480 }
481
482
483
484 buf = blk_try_blockalign(src, COMMIT_BUF_SIZE);
485 if (buf == NULL) {
486 ret = -ENOMEM;
487 goto ro_cleanup;
488 }
489
490 for (offset = 0; offset < length; offset += n) {
491 ret = bdrv_is_allocated(bs, offset, COMMIT_BUF_SIZE, &n);
492 if (ret < 0) {
493 goto ro_cleanup;
494 }
495 if (ret) {
496 ret = blk_pread(src, offset, buf, n);
497 if (ret < 0) {
498 goto ro_cleanup;
499 }
500
501 ret = blk_pwrite(backing, offset, buf, n, 0);
502 if (ret < 0) {
503 goto ro_cleanup;
504 }
505 }
506 }
507
508 if (drv->bdrv_make_empty) {
509 ret = drv->bdrv_make_empty(bs);
510 if (ret < 0) {
511 goto ro_cleanup;
512 }
513 blk_flush(src);
514 }
515
516
517
518
519
520 blk_flush(backing);
521
522 ret = 0;
523ro_cleanup:
524 qemu_vfree(buf);
525
526 blk_unref(backing);
527 if (backing_file_bs) {
528 bdrv_set_backing_hd(bs, backing_file_bs, &error_abort);
529 }
530 bdrv_unref(commit_top_bs);
531 blk_unref(src);
532
533 if (ro) {
534
535 bdrv_reopen(bs->backing->bs, open_flags & ~BDRV_O_RDWR, NULL);
536 }
537
538 return ret;
539}
540