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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 BlockDriverState *base_bs;
40 BlockdevOnError on_error;
41 int base_flags;
42 char *backing_file_str;
43} CommitBlockJob;
44
45static int coroutine_fn commit_populate(BlockBackend *bs, BlockBackend *base,
46 int64_t offset, uint64_t bytes,
47 void *buf)
48{
49 int ret = 0;
50 QEMUIOVector qiov;
51 struct iovec iov = {
52 .iov_base = buf,
53 .iov_len = bytes,
54 };
55
56 assert(bytes < SIZE_MAX);
57 qemu_iovec_init_external(&qiov, &iov, 1);
58
59 ret = blk_co_preadv(bs, offset, qiov.size, &qiov, 0);
60 if (ret < 0) {
61 return ret;
62 }
63
64 ret = blk_co_pwritev(base, offset, qiov.size, &qiov, 0);
65 if (ret < 0) {
66 return ret;
67 }
68
69 return 0;
70}
71
72static int commit_prepare(Job *job)
73{
74 CommitBlockJob *s = container_of(job, CommitBlockJob, common.job);
75
76
77
78 blk_unref(s->base);
79 s->base = NULL;
80
81
82
83 return bdrv_drop_intermediate(s->commit_top_bs, s->base_bs,
84 s->backing_file_str);
85}
86
87static void commit_abort(Job *job)
88{
89 CommitBlockJob *s = container_of(job, CommitBlockJob, common.job);
90 BlockDriverState *top_bs = blk_bs(s->top);
91
92
93 bdrv_ref(top_bs);
94 bdrv_ref(s->commit_top_bs);
95
96 if (s->base) {
97 blk_unref(s->base);
98 }
99
100
101
102 block_job_remove_all_bdrv(&s->common);
103
104
105
106
107
108
109
110
111 bdrv_child_try_set_perm(s->commit_top_bs->backing, 0, BLK_PERM_ALL,
112 &error_abort);
113 bdrv_replace_node(s->commit_top_bs, backing_bs(s->commit_top_bs),
114 &error_abort);
115
116 bdrv_unref(s->commit_top_bs);
117 bdrv_unref(top_bs);
118}
119
120static void commit_clean(Job *job)
121{
122 CommitBlockJob *s = container_of(job, CommitBlockJob, common.job);
123
124
125
126
127 if (s->base_flags != bdrv_get_flags(s->base_bs)) {
128 bdrv_reopen(s->base_bs, s->base_flags, NULL);
129 }
130
131 g_free(s->backing_file_str);
132 blk_unref(s->top);
133}
134
135static int coroutine_fn commit_run(Job *job, Error **errp)
136{
137 CommitBlockJob *s = container_of(job, CommitBlockJob, common.job);
138 int64_t offset;
139 uint64_t delay_ns = 0;
140 int ret = 0;
141 int64_t n = 0;
142 void *buf = NULL;
143 int bytes_written = 0;
144 int64_t len, base_len;
145
146 ret = len = blk_getlength(s->top);
147 if (len < 0) {
148 goto out;
149 }
150 job_progress_set_remaining(&s->common.job, len);
151
152 ret = base_len = blk_getlength(s->base);
153 if (base_len < 0) {
154 goto out;
155 }
156
157 if (base_len < len) {
158 ret = blk_truncate(s->base, len, PREALLOC_MODE_OFF, NULL);
159 if (ret) {
160 goto out;
161 }
162 }
163
164 buf = blk_blockalign(s->top, COMMIT_BUFFER_SIZE);
165
166 for (offset = 0; offset < len; offset += n) {
167 bool copy;
168
169
170
171
172 job_sleep_ns(&s->common.job, delay_ns);
173 if (job_is_cancelled(&s->common.job)) {
174 break;
175 }
176
177 ret = bdrv_is_allocated_above(blk_bs(s->top), blk_bs(s->base),
178 offset, COMMIT_BUFFER_SIZE, &n);
179 copy = (ret == 1);
180 trace_commit_one_iteration(s, offset, n, ret);
181 if (copy) {
182 ret = commit_populate(s->top, s->base, offset, n, buf);
183 bytes_written += n;
184 }
185 if (ret < 0) {
186 BlockErrorAction action =
187 block_job_error_action(&s->common, false, s->on_error, -ret);
188 if (action == BLOCK_ERROR_ACTION_REPORT) {
189 goto out;
190 } else {
191 n = 0;
192 continue;
193 }
194 }
195
196 job_progress_update(&s->common.job, n);
197
198 if (copy) {
199 delay_ns = block_job_ratelimit_get_delay(&s->common, n);
200 } else {
201 delay_ns = 0;
202 }
203 }
204
205 ret = 0;
206
207out:
208 qemu_vfree(buf);
209
210 return ret;
211}
212
213static const BlockJobDriver commit_job_driver = {
214 .job_driver = {
215 .instance_size = sizeof(CommitBlockJob),
216 .job_type = JOB_TYPE_COMMIT,
217 .free = block_job_free,
218 .user_resume = block_job_user_resume,
219 .drain = block_job_drain,
220 .run = commit_run,
221 .prepare = commit_prepare,
222 .abort = commit_abort,
223 .clean = commit_clean
224 },
225};
226
227static int coroutine_fn bdrv_commit_top_preadv(BlockDriverState *bs,
228 uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags)
229{
230 return bdrv_co_preadv(bs->backing, offset, bytes, qiov, flags);
231}
232
233static void bdrv_commit_top_refresh_filename(BlockDriverState *bs, QDict *opts)
234{
235 bdrv_refresh_filename(bs->backing->bs);
236 pstrcpy(bs->exact_filename, sizeof(bs->exact_filename),
237 bs->backing->bs->filename);
238}
239
240static void bdrv_commit_top_child_perm(BlockDriverState *bs, BdrvChild *c,
241 const BdrvChildRole *role,
242 BlockReopenQueue *reopen_queue,
243 uint64_t perm, uint64_t shared,
244 uint64_t *nperm, uint64_t *nshared)
245{
246 *nperm = 0;
247 *nshared = BLK_PERM_ALL;
248}
249
250
251
252static BlockDriver bdrv_commit_top = {
253 .format_name = "commit_top",
254 .bdrv_co_preadv = bdrv_commit_top_preadv,
255 .bdrv_co_block_status = bdrv_co_block_status_from_backing,
256 .bdrv_refresh_filename = bdrv_commit_top_refresh_filename,
257 .bdrv_child_perm = bdrv_commit_top_child_perm,
258};
259
260void commit_start(const char *job_id, BlockDriverState *bs,
261 BlockDriverState *base, BlockDriverState *top,
262 int creation_flags, int64_t speed,
263 BlockdevOnError on_error, const char *backing_file_str,
264 const char *filter_node_name, Error **errp)
265{
266 CommitBlockJob *s;
267 int orig_base_flags;
268 BlockDriverState *iter;
269 BlockDriverState *commit_top_bs = NULL;
270 Error *local_err = NULL;
271 int ret;
272
273 assert(top != bs);
274 if (top == base) {
275 error_setg(errp, "Invalid files for merge: top and base are the same");
276 return;
277 }
278
279 s = block_job_create(job_id, &commit_job_driver, NULL, bs, 0, BLK_PERM_ALL,
280 speed, creation_flags, NULL, NULL, errp);
281 if (!s) {
282 return;
283 }
284
285
286 orig_base_flags = bdrv_get_flags(base);
287 if (!(orig_base_flags & BDRV_O_RDWR)) {
288 bdrv_reopen(base, orig_base_flags | BDRV_O_RDWR, &local_err);
289 if (local_err != NULL) {
290 error_propagate(errp, local_err);
291 goto fail;
292 }
293 }
294
295
296
297 commit_top_bs = bdrv_new_open_driver(&bdrv_commit_top, filter_node_name, 0,
298 errp);
299 if (commit_top_bs == NULL) {
300 goto fail;
301 }
302 if (!filter_node_name) {
303 commit_top_bs->implicit = true;
304 }
305 commit_top_bs->total_sectors = top->total_sectors;
306 bdrv_set_aio_context(commit_top_bs, bdrv_get_aio_context(top));
307
308 bdrv_set_backing_hd(commit_top_bs, top, &local_err);
309 if (local_err) {
310 bdrv_unref(commit_top_bs);
311 commit_top_bs = NULL;
312 error_propagate(errp, local_err);
313 goto fail;
314 }
315 bdrv_replace_node(top, commit_top_bs, &local_err);
316 if (local_err) {
317 bdrv_unref(commit_top_bs);
318 commit_top_bs = NULL;
319 error_propagate(errp, local_err);
320 goto fail;
321 }
322
323 s->commit_top_bs = commit_top_bs;
324 bdrv_unref(commit_top_bs);
325
326
327
328 assert(bdrv_chain_contains(top, base));
329 for (iter = top; iter != base; iter = backing_bs(iter)) {
330
331
332
333
334 ret = block_job_add_bdrv(&s->common, "intermediate node", iter, 0,
335 BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE,
336 errp);
337 if (ret < 0) {
338 goto fail;
339 }
340 }
341
342 ret = block_job_add_bdrv(&s->common, "base", base, 0, BLK_PERM_ALL, errp);
343 if (ret < 0) {
344 goto fail;
345 }
346
347 s->base = blk_new(BLK_PERM_CONSISTENT_READ
348 | BLK_PERM_WRITE
349 | BLK_PERM_RESIZE,
350 BLK_PERM_CONSISTENT_READ
351 | BLK_PERM_GRAPH_MOD
352 | BLK_PERM_WRITE_UNCHANGED);
353 ret = blk_insert_bs(s->base, base, errp);
354 if (ret < 0) {
355 goto fail;
356 }
357 s->base_bs = base;
358
359
360 s->top = blk_new(0, BLK_PERM_ALL);
361 ret = blk_insert_bs(s->top, top, errp);
362 if (ret < 0) {
363 goto fail;
364 }
365
366 s->base_flags = orig_base_flags;
367 s->backing_file_str = g_strdup(backing_file_str);
368 s->on_error = on_error;
369
370 trace_commit_start(bs, base, top, s);
371 job_start(&s->common.job);
372 return;
373
374fail:
375 if (s->base) {
376 blk_unref(s->base);
377 }
378 if (s->top) {
379 blk_unref(s->top);
380 }
381 if (commit_top_bs) {
382 bdrv_replace_node(commit_top_bs, top, &error_abort);
383 }
384 job_early_fail(&s->common.job);
385}
386
387
388#define COMMIT_BUF_SIZE (2048 * BDRV_SECTOR_SIZE)
389
390
391int bdrv_commit(BlockDriverState *bs)
392{
393 BlockBackend *src, *backing;
394 BlockDriverState *backing_file_bs = NULL;
395 BlockDriverState *commit_top_bs = NULL;
396 BlockDriver *drv = bs->drv;
397 int64_t offset, length, backing_length;
398 int ro, open_flags;
399 int64_t n;
400 int ret = 0;
401 uint8_t *buf = NULL;
402 Error *local_err = NULL;
403
404 if (!drv)
405 return -ENOMEDIUM;
406
407 if (!bs->backing) {
408 return -ENOTSUP;
409 }
410
411 if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_COMMIT_SOURCE, NULL) ||
412 bdrv_op_is_blocked(bs->backing->bs, BLOCK_OP_TYPE_COMMIT_TARGET, NULL)) {
413 return -EBUSY;
414 }
415
416 ro = bs->backing->bs->read_only;
417 open_flags = bs->backing->bs->open_flags;
418
419 if (ro) {
420 if (bdrv_reopen(bs->backing->bs, open_flags | BDRV_O_RDWR, NULL)) {
421 return -EACCES;
422 }
423 }
424
425 src = blk_new(BLK_PERM_CONSISTENT_READ, BLK_PERM_ALL);
426 backing = blk_new(BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL);
427
428 ret = blk_insert_bs(src, bs, &local_err);
429 if (ret < 0) {
430 error_report_err(local_err);
431 goto ro_cleanup;
432 }
433
434
435 backing_file_bs = backing_bs(bs);
436
437 commit_top_bs = bdrv_new_open_driver(&bdrv_commit_top, NULL, BDRV_O_RDWR,
438 &local_err);
439 if (commit_top_bs == NULL) {
440 error_report_err(local_err);
441 goto ro_cleanup;
442 }
443 bdrv_set_aio_context(commit_top_bs, bdrv_get_aio_context(backing_file_bs));
444
445 bdrv_set_backing_hd(commit_top_bs, backing_file_bs, &error_abort);
446 bdrv_set_backing_hd(bs, commit_top_bs, &error_abort);
447
448 ret = blk_insert_bs(backing, backing_file_bs, &local_err);
449 if (ret < 0) {
450 error_report_err(local_err);
451 goto ro_cleanup;
452 }
453
454 length = blk_getlength(src);
455 if (length < 0) {
456 ret = length;
457 goto ro_cleanup;
458 }
459
460 backing_length = blk_getlength(backing);
461 if (backing_length < 0) {
462 ret = backing_length;
463 goto ro_cleanup;
464 }
465
466
467
468
469 if (length > backing_length) {
470 ret = blk_truncate(backing, length, PREALLOC_MODE_OFF, &local_err);
471 if (ret < 0) {
472 error_report_err(local_err);
473 goto ro_cleanup;
474 }
475 }
476
477
478
479 buf = blk_try_blockalign(src, COMMIT_BUF_SIZE);
480 if (buf == NULL) {
481 ret = -ENOMEM;
482 goto ro_cleanup;
483 }
484
485 for (offset = 0; offset < length; offset += n) {
486 ret = bdrv_is_allocated(bs, offset, COMMIT_BUF_SIZE, &n);
487 if (ret < 0) {
488 goto ro_cleanup;
489 }
490 if (ret) {
491 ret = blk_pread(src, offset, buf, n);
492 if (ret < 0) {
493 goto ro_cleanup;
494 }
495
496 ret = blk_pwrite(backing, offset, buf, n, 0);
497 if (ret < 0) {
498 goto ro_cleanup;
499 }
500 }
501 }
502
503 if (drv->bdrv_make_empty) {
504 ret = drv->bdrv_make_empty(bs);
505 if (ret < 0) {
506 goto ro_cleanup;
507 }
508 blk_flush(src);
509 }
510
511
512
513
514
515 blk_flush(backing);
516
517 ret = 0;
518ro_cleanup:
519 qemu_vfree(buf);
520
521 blk_unref(backing);
522 if (backing_file_bs) {
523 bdrv_set_backing_hd(bs, backing_file_bs, &error_abort);
524 }
525 bdrv_unref(commit_top_bs);
526 blk_unref(src);
527
528 if (ro) {
529
530 bdrv_reopen(bs->backing->bs, open_flags & ~BDRV_O_RDWR, NULL);
531 }
532
533 return ret;
534}
535