]> git.proxmox.com Git - mirror_qemu.git/blob - block/mirror.c
Merge remote-tracking branch 'remotes/bsdimp/tags/pull-bsd-user-20210511' into staging
[mirror_qemu.git] / block / mirror.c
1 /*
2 * Image mirroring
3 *
4 * Copyright Red Hat, Inc. 2012
5 *
6 * Authors:
7 * Paolo Bonzini <pbonzini@redhat.com>
8 *
9 * This work is licensed under the terms of the GNU LGPL, version 2 or later.
10 * See the COPYING.LIB file in the top-level directory.
11 *
12 */
13
14 #include "qemu/osdep.h"
15 #include "qemu/cutils.h"
16 #include "qemu/coroutine.h"
17 #include "qemu/range.h"
18 #include "trace.h"
19 #include "block/blockjob_int.h"
20 #include "block/block_int.h"
21 #include "sysemu/block-backend.h"
22 #include "qapi/error.h"
23 #include "qapi/qmp/qerror.h"
24 #include "qemu/ratelimit.h"
25 #include "qemu/bitmap.h"
26
27 #define MAX_IN_FLIGHT 16
28 #define MAX_IO_BYTES (1 << 20) /* 1 Mb */
29 #define DEFAULT_MIRROR_BUF_SIZE (MAX_IN_FLIGHT * MAX_IO_BYTES)
30
31 /* The mirroring buffer is a list of granularity-sized chunks.
32 * Free chunks are organized in a list.
33 */
34 typedef struct MirrorBuffer {
35 QSIMPLEQ_ENTRY(MirrorBuffer) next;
36 } MirrorBuffer;
37
38 typedef struct MirrorOp MirrorOp;
39
40 typedef struct MirrorBlockJob {
41 BlockJob common;
42 BlockBackend *target;
43 BlockDriverState *mirror_top_bs;
44 BlockDriverState *base;
45 BlockDriverState *base_overlay;
46
47 /* The name of the graph node to replace */
48 char *replaces;
49 /* The BDS to replace */
50 BlockDriverState *to_replace;
51 /* Used to block operations on the drive-mirror-replace target */
52 Error *replace_blocker;
53 bool is_none_mode;
54 BlockMirrorBackingMode backing_mode;
55 /* Whether the target image requires explicit zero-initialization */
56 bool zero_target;
57 MirrorCopyMode copy_mode;
58 BlockdevOnError on_source_error, on_target_error;
59 bool synced;
60 /* Set when the target is synced (dirty bitmap is clean, nothing
61 * in flight) and the job is running in active mode */
62 bool actively_synced;
63 bool should_complete;
64 int64_t granularity;
65 size_t buf_size;
66 int64_t bdev_length;
67 unsigned long *cow_bitmap;
68 BdrvDirtyBitmap *dirty_bitmap;
69 BdrvDirtyBitmapIter *dbi;
70 uint8_t *buf;
71 QSIMPLEQ_HEAD(, MirrorBuffer) buf_free;
72 int buf_free_count;
73
74 uint64_t last_pause_ns;
75 unsigned long *in_flight_bitmap;
76 int in_flight;
77 int64_t bytes_in_flight;
78 QTAILQ_HEAD(, MirrorOp) ops_in_flight;
79 int ret;
80 bool unmap;
81 int target_cluster_size;
82 int max_iov;
83 bool initial_zeroing_ongoing;
84 int in_active_write_counter;
85 bool prepared;
86 bool in_drain;
87 } MirrorBlockJob;
88
89 typedef struct MirrorBDSOpaque {
90 MirrorBlockJob *job;
91 bool stop;
92 bool is_commit;
93 } MirrorBDSOpaque;
94
95 struct MirrorOp {
96 MirrorBlockJob *s;
97 QEMUIOVector qiov;
98 int64_t offset;
99 uint64_t bytes;
100
101 /* The pointee is set by mirror_co_read(), mirror_co_zero(), and
102 * mirror_co_discard() before yielding for the first time */
103 int64_t *bytes_handled;
104
105 bool is_pseudo_op;
106 bool is_active_write;
107 bool is_in_flight;
108 CoQueue waiting_requests;
109 Coroutine *co;
110
111 QTAILQ_ENTRY(MirrorOp) next;
112 };
113
114 typedef enum MirrorMethod {
115 MIRROR_METHOD_COPY,
116 MIRROR_METHOD_ZERO,
117 MIRROR_METHOD_DISCARD,
118 } MirrorMethod;
119
120 static BlockErrorAction mirror_error_action(MirrorBlockJob *s, bool read,
121 int error)
122 {
123 s->synced = false;
124 s->actively_synced = false;
125 if (read) {
126 return block_job_error_action(&s->common, s->on_source_error,
127 true, error);
128 } else {
129 return block_job_error_action(&s->common, s->on_target_error,
130 false, error);
131 }
132 }
133
134 static void coroutine_fn mirror_wait_on_conflicts(MirrorOp *self,
135 MirrorBlockJob *s,
136 uint64_t offset,
137 uint64_t bytes)
138 {
139 uint64_t self_start_chunk = offset / s->granularity;
140 uint64_t self_end_chunk = DIV_ROUND_UP(offset + bytes, s->granularity);
141 uint64_t self_nb_chunks = self_end_chunk - self_start_chunk;
142
143 while (find_next_bit(s->in_flight_bitmap, self_end_chunk,
144 self_start_chunk) < self_end_chunk &&
145 s->ret >= 0)
146 {
147 MirrorOp *op;
148
149 QTAILQ_FOREACH(op, &s->ops_in_flight, next) {
150 uint64_t op_start_chunk = op->offset / s->granularity;
151 uint64_t op_nb_chunks = DIV_ROUND_UP(op->offset + op->bytes,
152 s->granularity) -
153 op_start_chunk;
154
155 if (op == self) {
156 continue;
157 }
158
159 if (ranges_overlap(self_start_chunk, self_nb_chunks,
160 op_start_chunk, op_nb_chunks))
161 {
162 qemu_co_queue_wait(&op->waiting_requests, NULL);
163 break;
164 }
165 }
166 }
167 }
168
169 static void coroutine_fn mirror_iteration_done(MirrorOp *op, int ret)
170 {
171 MirrorBlockJob *s = op->s;
172 struct iovec *iov;
173 int64_t chunk_num;
174 int i, nb_chunks;
175
176 trace_mirror_iteration_done(s, op->offset, op->bytes, ret);
177
178 s->in_flight--;
179 s->bytes_in_flight -= op->bytes;
180 iov = op->qiov.iov;
181 for (i = 0; i < op->qiov.niov; i++) {
182 MirrorBuffer *buf = (MirrorBuffer *) iov[i].iov_base;
183 QSIMPLEQ_INSERT_TAIL(&s->buf_free, buf, next);
184 s->buf_free_count++;
185 }
186
187 chunk_num = op->offset / s->granularity;
188 nb_chunks = DIV_ROUND_UP(op->bytes, s->granularity);
189
190 bitmap_clear(s->in_flight_bitmap, chunk_num, nb_chunks);
191 QTAILQ_REMOVE(&s->ops_in_flight, op, next);
192 if (ret >= 0) {
193 if (s->cow_bitmap) {
194 bitmap_set(s->cow_bitmap, chunk_num, nb_chunks);
195 }
196 if (!s->initial_zeroing_ongoing) {
197 job_progress_update(&s->common.job, op->bytes);
198 }
199 }
200 qemu_iovec_destroy(&op->qiov);
201
202 qemu_co_queue_restart_all(&op->waiting_requests);
203 g_free(op);
204 }
205
206 static void coroutine_fn mirror_write_complete(MirrorOp *op, int ret)
207 {
208 MirrorBlockJob *s = op->s;
209
210 if (ret < 0) {
211 BlockErrorAction action;
212
213 bdrv_set_dirty_bitmap(s->dirty_bitmap, op->offset, op->bytes);
214 action = mirror_error_action(s, false, -ret);
215 if (action == BLOCK_ERROR_ACTION_REPORT && s->ret >= 0) {
216 s->ret = ret;
217 }
218 }
219
220 mirror_iteration_done(op, ret);
221 }
222
223 static void coroutine_fn mirror_read_complete(MirrorOp *op, int ret)
224 {
225 MirrorBlockJob *s = op->s;
226
227 if (ret < 0) {
228 BlockErrorAction action;
229
230 bdrv_set_dirty_bitmap(s->dirty_bitmap, op->offset, op->bytes);
231 action = mirror_error_action(s, true, -ret);
232 if (action == BLOCK_ERROR_ACTION_REPORT && s->ret >= 0) {
233 s->ret = ret;
234 }
235
236 mirror_iteration_done(op, ret);
237 return;
238 }
239
240 ret = blk_co_pwritev(s->target, op->offset, op->qiov.size, &op->qiov, 0);
241 mirror_write_complete(op, ret);
242 }
243
244 /* Clip bytes relative to offset to not exceed end-of-file */
245 static inline int64_t mirror_clip_bytes(MirrorBlockJob *s,
246 int64_t offset,
247 int64_t bytes)
248 {
249 return MIN(bytes, s->bdev_length - offset);
250 }
251
252 /* Round offset and/or bytes to target cluster if COW is needed, and
253 * return the offset of the adjusted tail against original. */
254 static int mirror_cow_align(MirrorBlockJob *s, int64_t *offset,
255 uint64_t *bytes)
256 {
257 bool need_cow;
258 int ret = 0;
259 int64_t align_offset = *offset;
260 int64_t align_bytes = *bytes;
261 int max_bytes = s->granularity * s->max_iov;
262
263 need_cow = !test_bit(*offset / s->granularity, s->cow_bitmap);
264 need_cow |= !test_bit((*offset + *bytes - 1) / s->granularity,
265 s->cow_bitmap);
266 if (need_cow) {
267 bdrv_round_to_clusters(blk_bs(s->target), *offset, *bytes,
268 &align_offset, &align_bytes);
269 }
270
271 if (align_bytes > max_bytes) {
272 align_bytes = max_bytes;
273 if (need_cow) {
274 align_bytes = QEMU_ALIGN_DOWN(align_bytes, s->target_cluster_size);
275 }
276 }
277 /* Clipping may result in align_bytes unaligned to chunk boundary, but
278 * that doesn't matter because it's already the end of source image. */
279 align_bytes = mirror_clip_bytes(s, align_offset, align_bytes);
280
281 ret = align_offset + align_bytes - (*offset + *bytes);
282 *offset = align_offset;
283 *bytes = align_bytes;
284 assert(ret >= 0);
285 return ret;
286 }
287
288 static inline void coroutine_fn
289 mirror_wait_for_any_operation(MirrorBlockJob *s, bool active)
290 {
291 MirrorOp *op;
292
293 QTAILQ_FOREACH(op, &s->ops_in_flight, next) {
294 /* Do not wait on pseudo ops, because it may in turn wait on
295 * some other operation to start, which may in fact be the
296 * caller of this function. Since there is only one pseudo op
297 * at any given time, we will always find some real operation
298 * to wait on. */
299 if (!op->is_pseudo_op && op->is_in_flight &&
300 op->is_active_write == active)
301 {
302 qemu_co_queue_wait(&op->waiting_requests, NULL);
303 return;
304 }
305 }
306 abort();
307 }
308
309 static inline void coroutine_fn
310 mirror_wait_for_free_in_flight_slot(MirrorBlockJob *s)
311 {
312 /* Only non-active operations use up in-flight slots */
313 mirror_wait_for_any_operation(s, false);
314 }
315
316 /* Perform a mirror copy operation.
317 *
318 * *op->bytes_handled is set to the number of bytes copied after and
319 * including offset, excluding any bytes copied prior to offset due
320 * to alignment. This will be op->bytes if no alignment is necessary,
321 * or (new_end - op->offset) if the tail is rounded up or down due to
322 * alignment or buffer limit.
323 */
324 static void coroutine_fn mirror_co_read(void *opaque)
325 {
326 MirrorOp *op = opaque;
327 MirrorBlockJob *s = op->s;
328 int nb_chunks;
329 uint64_t ret;
330 uint64_t max_bytes;
331
332 max_bytes = s->granularity * s->max_iov;
333
334 /* We can only handle as much as buf_size at a time. */
335 op->bytes = MIN(s->buf_size, MIN(max_bytes, op->bytes));
336 assert(op->bytes);
337 assert(op->bytes < BDRV_REQUEST_MAX_BYTES);
338 *op->bytes_handled = op->bytes;
339
340 if (s->cow_bitmap) {
341 *op->bytes_handled += mirror_cow_align(s, &op->offset, &op->bytes);
342 }
343 /* Cannot exceed BDRV_REQUEST_MAX_BYTES + INT_MAX */
344 assert(*op->bytes_handled <= UINT_MAX);
345 assert(op->bytes <= s->buf_size);
346 /* The offset is granularity-aligned because:
347 * 1) Caller passes in aligned values;
348 * 2) mirror_cow_align is used only when target cluster is larger. */
349 assert(QEMU_IS_ALIGNED(op->offset, s->granularity));
350 /* The range is sector-aligned, since bdrv_getlength() rounds up. */
351 assert(QEMU_IS_ALIGNED(op->bytes, BDRV_SECTOR_SIZE));
352 nb_chunks = DIV_ROUND_UP(op->bytes, s->granularity);
353
354 while (s->buf_free_count < nb_chunks) {
355 trace_mirror_yield_in_flight(s, op->offset, s->in_flight);
356 mirror_wait_for_free_in_flight_slot(s);
357 }
358
359 /* Now make a QEMUIOVector taking enough granularity-sized chunks
360 * from s->buf_free.
361 */
362 qemu_iovec_init(&op->qiov, nb_chunks);
363 while (nb_chunks-- > 0) {
364 MirrorBuffer *buf = QSIMPLEQ_FIRST(&s->buf_free);
365 size_t remaining = op->bytes - op->qiov.size;
366
367 QSIMPLEQ_REMOVE_HEAD(&s->buf_free, next);
368 s->buf_free_count--;
369 qemu_iovec_add(&op->qiov, buf, MIN(s->granularity, remaining));
370 }
371
372 /* Copy the dirty cluster. */
373 s->in_flight++;
374 s->bytes_in_flight += op->bytes;
375 op->is_in_flight = true;
376 trace_mirror_one_iteration(s, op->offset, op->bytes);
377
378 ret = bdrv_co_preadv(s->mirror_top_bs->backing, op->offset, op->bytes,
379 &op->qiov, 0);
380 mirror_read_complete(op, ret);
381 }
382
383 static void coroutine_fn mirror_co_zero(void *opaque)
384 {
385 MirrorOp *op = opaque;
386 int ret;
387
388 op->s->in_flight++;
389 op->s->bytes_in_flight += op->bytes;
390 *op->bytes_handled = op->bytes;
391 op->is_in_flight = true;
392
393 ret = blk_co_pwrite_zeroes(op->s->target, op->offset, op->bytes,
394 op->s->unmap ? BDRV_REQ_MAY_UNMAP : 0);
395 mirror_write_complete(op, ret);
396 }
397
398 static void coroutine_fn mirror_co_discard(void *opaque)
399 {
400 MirrorOp *op = opaque;
401 int ret;
402
403 op->s->in_flight++;
404 op->s->bytes_in_flight += op->bytes;
405 *op->bytes_handled = op->bytes;
406 op->is_in_flight = true;
407
408 ret = blk_co_pdiscard(op->s->target, op->offset, op->bytes);
409 mirror_write_complete(op, ret);
410 }
411
412 static unsigned mirror_perform(MirrorBlockJob *s, int64_t offset,
413 unsigned bytes, MirrorMethod mirror_method)
414 {
415 MirrorOp *op;
416 Coroutine *co;
417 int64_t bytes_handled = -1;
418
419 op = g_new(MirrorOp, 1);
420 *op = (MirrorOp){
421 .s = s,
422 .offset = offset,
423 .bytes = bytes,
424 .bytes_handled = &bytes_handled,
425 };
426 qemu_co_queue_init(&op->waiting_requests);
427
428 switch (mirror_method) {
429 case MIRROR_METHOD_COPY:
430 co = qemu_coroutine_create(mirror_co_read, op);
431 break;
432 case MIRROR_METHOD_ZERO:
433 co = qemu_coroutine_create(mirror_co_zero, op);
434 break;
435 case MIRROR_METHOD_DISCARD:
436 co = qemu_coroutine_create(mirror_co_discard, op);
437 break;
438 default:
439 abort();
440 }
441 op->co = co;
442
443 QTAILQ_INSERT_TAIL(&s->ops_in_flight, op, next);
444 qemu_coroutine_enter(co);
445 /* At this point, ownership of op has been moved to the coroutine
446 * and the object may already be freed */
447
448 /* Assert that this value has been set */
449 assert(bytes_handled >= 0);
450
451 /* Same assertion as in mirror_co_read() (and for mirror_co_read()
452 * and mirror_co_discard(), bytes_handled == op->bytes, which
453 * is the @bytes parameter given to this function) */
454 assert(bytes_handled <= UINT_MAX);
455 return bytes_handled;
456 }
457
458 static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
459 {
460 BlockDriverState *source = s->mirror_top_bs->backing->bs;
461 MirrorOp *pseudo_op;
462 int64_t offset;
463 uint64_t delay_ns = 0, ret = 0;
464 /* At least the first dirty chunk is mirrored in one iteration. */
465 int nb_chunks = 1;
466 bool write_zeroes_ok = bdrv_can_write_zeroes_with_unmap(blk_bs(s->target));
467 int max_io_bytes = MAX(s->buf_size / MAX_IN_FLIGHT, MAX_IO_BYTES);
468
469 bdrv_dirty_bitmap_lock(s->dirty_bitmap);
470 offset = bdrv_dirty_iter_next(s->dbi);
471 if (offset < 0) {
472 bdrv_set_dirty_iter(s->dbi, 0);
473 offset = bdrv_dirty_iter_next(s->dbi);
474 trace_mirror_restart_iter(s, bdrv_get_dirty_count(s->dirty_bitmap));
475 assert(offset >= 0);
476 }
477 bdrv_dirty_bitmap_unlock(s->dirty_bitmap);
478
479 mirror_wait_on_conflicts(NULL, s, offset, 1);
480
481 job_pause_point(&s->common.job);
482
483 /* Find the number of consective dirty chunks following the first dirty
484 * one, and wait for in flight requests in them. */
485 bdrv_dirty_bitmap_lock(s->dirty_bitmap);
486 while (nb_chunks * s->granularity < s->buf_size) {
487 int64_t next_dirty;
488 int64_t next_offset = offset + nb_chunks * s->granularity;
489 int64_t next_chunk = next_offset / s->granularity;
490 if (next_offset >= s->bdev_length ||
491 !bdrv_dirty_bitmap_get_locked(s->dirty_bitmap, next_offset)) {
492 break;
493 }
494 if (test_bit(next_chunk, s->in_flight_bitmap)) {
495 break;
496 }
497
498 next_dirty = bdrv_dirty_iter_next(s->dbi);
499 if (next_dirty > next_offset || next_dirty < 0) {
500 /* The bitmap iterator's cache is stale, refresh it */
501 bdrv_set_dirty_iter(s->dbi, next_offset);
502 next_dirty = bdrv_dirty_iter_next(s->dbi);
503 }
504 assert(next_dirty == next_offset);
505 nb_chunks++;
506 }
507
508 /* Clear dirty bits before querying the block status, because
509 * calling bdrv_block_status_above could yield - if some blocks are
510 * marked dirty in this window, we need to know.
511 */
512 bdrv_reset_dirty_bitmap_locked(s->dirty_bitmap, offset,
513 nb_chunks * s->granularity);
514 bdrv_dirty_bitmap_unlock(s->dirty_bitmap);
515
516 /* Before claiming an area in the in-flight bitmap, we have to
517 * create a MirrorOp for it so that conflicting requests can wait
518 * for it. mirror_perform() will create the real MirrorOps later,
519 * for now we just create a pseudo operation that will wake up all
520 * conflicting requests once all real operations have been
521 * launched. */
522 pseudo_op = g_new(MirrorOp, 1);
523 *pseudo_op = (MirrorOp){
524 .offset = offset,
525 .bytes = nb_chunks * s->granularity,
526 .is_pseudo_op = true,
527 };
528 qemu_co_queue_init(&pseudo_op->waiting_requests);
529 QTAILQ_INSERT_TAIL(&s->ops_in_flight, pseudo_op, next);
530
531 bitmap_set(s->in_flight_bitmap, offset / s->granularity, nb_chunks);
532 while (nb_chunks > 0 && offset < s->bdev_length) {
533 int ret;
534 int64_t io_bytes;
535 int64_t io_bytes_acct;
536 MirrorMethod mirror_method = MIRROR_METHOD_COPY;
537
538 assert(!(offset % s->granularity));
539 ret = bdrv_block_status_above(source, NULL, offset,
540 nb_chunks * s->granularity,
541 &io_bytes, NULL, NULL);
542 if (ret < 0) {
543 io_bytes = MIN(nb_chunks * s->granularity, max_io_bytes);
544 } else if (ret & BDRV_BLOCK_DATA) {
545 io_bytes = MIN(io_bytes, max_io_bytes);
546 }
547
548 io_bytes -= io_bytes % s->granularity;
549 if (io_bytes < s->granularity) {
550 io_bytes = s->granularity;
551 } else if (ret >= 0 && !(ret & BDRV_BLOCK_DATA)) {
552 int64_t target_offset;
553 int64_t target_bytes;
554 bdrv_round_to_clusters(blk_bs(s->target), offset, io_bytes,
555 &target_offset, &target_bytes);
556 if (target_offset == offset &&
557 target_bytes == io_bytes) {
558 mirror_method = ret & BDRV_BLOCK_ZERO ?
559 MIRROR_METHOD_ZERO :
560 MIRROR_METHOD_DISCARD;
561 }
562 }
563
564 while (s->in_flight >= MAX_IN_FLIGHT) {
565 trace_mirror_yield_in_flight(s, offset, s->in_flight);
566 mirror_wait_for_free_in_flight_slot(s);
567 }
568
569 if (s->ret < 0) {
570 ret = 0;
571 goto fail;
572 }
573
574 io_bytes = mirror_clip_bytes(s, offset, io_bytes);
575 io_bytes = mirror_perform(s, offset, io_bytes, mirror_method);
576 if (mirror_method != MIRROR_METHOD_COPY && write_zeroes_ok) {
577 io_bytes_acct = 0;
578 } else {
579 io_bytes_acct = io_bytes;
580 }
581 assert(io_bytes);
582 offset += io_bytes;
583 nb_chunks -= DIV_ROUND_UP(io_bytes, s->granularity);
584 delay_ns = block_job_ratelimit_get_delay(&s->common, io_bytes_acct);
585 }
586
587 ret = delay_ns;
588 fail:
589 QTAILQ_REMOVE(&s->ops_in_flight, pseudo_op, next);
590 qemu_co_queue_restart_all(&pseudo_op->waiting_requests);
591 g_free(pseudo_op);
592
593 return ret;
594 }
595
596 static void mirror_free_init(MirrorBlockJob *s)
597 {
598 int granularity = s->granularity;
599 size_t buf_size = s->buf_size;
600 uint8_t *buf = s->buf;
601
602 assert(s->buf_free_count == 0);
603 QSIMPLEQ_INIT(&s->buf_free);
604 while (buf_size != 0) {
605 MirrorBuffer *cur = (MirrorBuffer *)buf;
606 QSIMPLEQ_INSERT_TAIL(&s->buf_free, cur, next);
607 s->buf_free_count++;
608 buf_size -= granularity;
609 buf += granularity;
610 }
611 }
612
613 /* This is also used for the .pause callback. There is no matching
614 * mirror_resume() because mirror_run() will begin iterating again
615 * when the job is resumed.
616 */
617 static void coroutine_fn mirror_wait_for_all_io(MirrorBlockJob *s)
618 {
619 while (s->in_flight > 0) {
620 mirror_wait_for_free_in_flight_slot(s);
621 }
622 }
623
624 /**
625 * mirror_exit_common: handle both abort() and prepare() cases.
626 * for .prepare, returns 0 on success and -errno on failure.
627 * for .abort cases, denoted by abort = true, MUST return 0.
628 */
629 static int mirror_exit_common(Job *job)
630 {
631 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common.job);
632 BlockJob *bjob = &s->common;
633 MirrorBDSOpaque *bs_opaque;
634 AioContext *replace_aio_context = NULL;
635 BlockDriverState *src;
636 BlockDriverState *target_bs;
637 BlockDriverState *mirror_top_bs;
638 Error *local_err = NULL;
639 bool abort = job->ret < 0;
640 int ret = 0;
641
642 if (s->prepared) {
643 return 0;
644 }
645 s->prepared = true;
646
647 mirror_top_bs = s->mirror_top_bs;
648 bs_opaque = mirror_top_bs->opaque;
649 src = mirror_top_bs->backing->bs;
650 target_bs = blk_bs(s->target);
651
652 if (bdrv_chain_contains(src, target_bs)) {
653 bdrv_unfreeze_backing_chain(mirror_top_bs, target_bs);
654 }
655
656 bdrv_release_dirty_bitmap(s->dirty_bitmap);
657
658 /* Make sure that the source BDS doesn't go away during bdrv_replace_node,
659 * before we can call bdrv_drained_end */
660 bdrv_ref(src);
661 bdrv_ref(mirror_top_bs);
662 bdrv_ref(target_bs);
663
664 /*
665 * Remove target parent that still uses BLK_PERM_WRITE/RESIZE before
666 * inserting target_bs at s->to_replace, where we might not be able to get
667 * these permissions.
668 */
669 blk_unref(s->target);
670 s->target = NULL;
671
672 /* We don't access the source any more. Dropping any WRITE/RESIZE is
673 * required before it could become a backing file of target_bs. Not having
674 * these permissions any more means that we can't allow any new requests on
675 * mirror_top_bs from now on, so keep it drained. */
676 bdrv_drained_begin(mirror_top_bs);
677 bs_opaque->stop = true;
678 bdrv_child_refresh_perms(mirror_top_bs, mirror_top_bs->backing,
679 &error_abort);
680 if (!abort && s->backing_mode == MIRROR_SOURCE_BACKING_CHAIN) {
681 BlockDriverState *backing = s->is_none_mode ? src : s->base;
682 BlockDriverState *unfiltered_target = bdrv_skip_filters(target_bs);
683
684 if (bdrv_cow_bs(unfiltered_target) != backing) {
685 bdrv_set_backing_hd(unfiltered_target, backing, &local_err);
686 if (local_err) {
687 error_report_err(local_err);
688 local_err = NULL;
689 ret = -EPERM;
690 }
691 }
692 } else if (!abort && s->backing_mode == MIRROR_OPEN_BACKING_CHAIN) {
693 assert(!bdrv_backing_chain_next(target_bs));
694 ret = bdrv_open_backing_file(bdrv_skip_filters(target_bs), NULL,
695 "backing", &local_err);
696 if (ret < 0) {
697 error_report_err(local_err);
698 local_err = NULL;
699 }
700 }
701
702 if (s->to_replace) {
703 replace_aio_context = bdrv_get_aio_context(s->to_replace);
704 aio_context_acquire(replace_aio_context);
705 }
706
707 if (s->should_complete && !abort) {
708 BlockDriverState *to_replace = s->to_replace ?: src;
709 bool ro = bdrv_is_read_only(to_replace);
710
711 if (ro != bdrv_is_read_only(target_bs)) {
712 bdrv_reopen_set_read_only(target_bs, ro, NULL);
713 }
714
715 /* The mirror job has no requests in flight any more, but we need to
716 * drain potential other users of the BDS before changing the graph. */
717 assert(s->in_drain);
718 bdrv_drained_begin(target_bs);
719 /*
720 * Cannot use check_to_replace_node() here, because that would
721 * check for an op blocker on @to_replace, and we have our own
722 * there.
723 */
724 if (bdrv_recurse_can_replace(src, to_replace)) {
725 bdrv_replace_node(to_replace, target_bs, &local_err);
726 } else {
727 error_setg(&local_err, "Can no longer replace '%s' by '%s', "
728 "because it can no longer be guaranteed that doing so "
729 "would not lead to an abrupt change of visible data",
730 to_replace->node_name, target_bs->node_name);
731 }
732 bdrv_drained_end(target_bs);
733 if (local_err) {
734 error_report_err(local_err);
735 ret = -EPERM;
736 }
737 }
738 if (s->to_replace) {
739 bdrv_op_unblock_all(s->to_replace, s->replace_blocker);
740 error_free(s->replace_blocker);
741 bdrv_unref(s->to_replace);
742 }
743 if (replace_aio_context) {
744 aio_context_release(replace_aio_context);
745 }
746 g_free(s->replaces);
747 bdrv_unref(target_bs);
748
749 /*
750 * Remove the mirror filter driver from the graph. Before this, get rid of
751 * the blockers on the intermediate nodes so that the resulting state is
752 * valid.
753 */
754 block_job_remove_all_bdrv(bjob);
755 bdrv_replace_node(mirror_top_bs, mirror_top_bs->backing->bs, &error_abort);
756
757 /* We just changed the BDS the job BB refers to (with either or both of the
758 * bdrv_replace_node() calls), so switch the BB back so the cleanup does
759 * the right thing. We don't need any permissions any more now. */
760 blk_remove_bs(bjob->blk);
761 blk_set_perm(bjob->blk, 0, BLK_PERM_ALL, &error_abort);
762 blk_insert_bs(bjob->blk, mirror_top_bs, &error_abort);
763
764 bs_opaque->job = NULL;
765
766 bdrv_drained_end(src);
767 bdrv_drained_end(mirror_top_bs);
768 s->in_drain = false;
769 bdrv_unref(mirror_top_bs);
770 bdrv_unref(src);
771
772 return ret;
773 }
774
775 static int mirror_prepare(Job *job)
776 {
777 return mirror_exit_common(job);
778 }
779
780 static void mirror_abort(Job *job)
781 {
782 int ret = mirror_exit_common(job);
783 assert(ret == 0);
784 }
785
786 static void coroutine_fn mirror_throttle(MirrorBlockJob *s)
787 {
788 int64_t now = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
789
790 if (now - s->last_pause_ns > BLOCK_JOB_SLICE_TIME) {
791 s->last_pause_ns = now;
792 job_sleep_ns(&s->common.job, 0);
793 } else {
794 job_pause_point(&s->common.job);
795 }
796 }
797
798 static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s)
799 {
800 int64_t offset;
801 BlockDriverState *bs = s->mirror_top_bs->backing->bs;
802 BlockDriverState *target_bs = blk_bs(s->target);
803 int ret;
804 int64_t count;
805
806 if (s->zero_target) {
807 if (!bdrv_can_write_zeroes_with_unmap(target_bs)) {
808 bdrv_set_dirty_bitmap(s->dirty_bitmap, 0, s->bdev_length);
809 return 0;
810 }
811
812 s->initial_zeroing_ongoing = true;
813 for (offset = 0; offset < s->bdev_length; ) {
814 int bytes = MIN(s->bdev_length - offset,
815 QEMU_ALIGN_DOWN(INT_MAX, s->granularity));
816
817 mirror_throttle(s);
818
819 if (job_is_cancelled(&s->common.job)) {
820 s->initial_zeroing_ongoing = false;
821 return 0;
822 }
823
824 if (s->in_flight >= MAX_IN_FLIGHT) {
825 trace_mirror_yield(s, UINT64_MAX, s->buf_free_count,
826 s->in_flight);
827 mirror_wait_for_free_in_flight_slot(s);
828 continue;
829 }
830
831 mirror_perform(s, offset, bytes, MIRROR_METHOD_ZERO);
832 offset += bytes;
833 }
834
835 mirror_wait_for_all_io(s);
836 s->initial_zeroing_ongoing = false;
837 }
838
839 /* First part, loop on the sectors and initialize the dirty bitmap. */
840 for (offset = 0; offset < s->bdev_length; ) {
841 /* Just to make sure we are not exceeding int limit. */
842 int bytes = MIN(s->bdev_length - offset,
843 QEMU_ALIGN_DOWN(INT_MAX, s->granularity));
844
845 mirror_throttle(s);
846
847 if (job_is_cancelled(&s->common.job)) {
848 return 0;
849 }
850
851 ret = bdrv_is_allocated_above(bs, s->base_overlay, true, offset, bytes,
852 &count);
853 if (ret < 0) {
854 return ret;
855 }
856
857 assert(count);
858 if (ret > 0) {
859 bdrv_set_dirty_bitmap(s->dirty_bitmap, offset, count);
860 }
861 offset += count;
862 }
863 return 0;
864 }
865
866 /* Called when going out of the streaming phase to flush the bulk of the
867 * data to the medium, or just before completing.
868 */
869 static int mirror_flush(MirrorBlockJob *s)
870 {
871 int ret = blk_flush(s->target);
872 if (ret < 0) {
873 if (mirror_error_action(s, false, -ret) == BLOCK_ERROR_ACTION_REPORT) {
874 s->ret = ret;
875 }
876 }
877 return ret;
878 }
879
880 static int coroutine_fn mirror_run(Job *job, Error **errp)
881 {
882 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common.job);
883 BlockDriverState *bs = s->mirror_top_bs->backing->bs;
884 BlockDriverState *target_bs = blk_bs(s->target);
885 bool need_drain = true;
886 int64_t length;
887 int64_t target_length;
888 BlockDriverInfo bdi;
889 char backing_filename[2]; /* we only need 2 characters because we are only
890 checking for a NULL string */
891 int ret = 0;
892
893 if (job_is_cancelled(&s->common.job)) {
894 goto immediate_exit;
895 }
896
897 s->bdev_length = bdrv_getlength(bs);
898 if (s->bdev_length < 0) {
899 ret = s->bdev_length;
900 goto immediate_exit;
901 }
902
903 target_length = blk_getlength(s->target);
904 if (target_length < 0) {
905 ret = target_length;
906 goto immediate_exit;
907 }
908
909 /* Active commit must resize the base image if its size differs from the
910 * active layer. */
911 if (s->base == blk_bs(s->target)) {
912 if (s->bdev_length > target_length) {
913 ret = blk_truncate(s->target, s->bdev_length, false,
914 PREALLOC_MODE_OFF, 0, NULL);
915 if (ret < 0) {
916 goto immediate_exit;
917 }
918 }
919 } else if (s->bdev_length != target_length) {
920 error_setg(errp, "Source and target image have different sizes");
921 ret = -EINVAL;
922 goto immediate_exit;
923 }
924
925 if (s->bdev_length == 0) {
926 /* Transition to the READY state and wait for complete. */
927 job_transition_to_ready(&s->common.job);
928 s->synced = true;
929 s->actively_synced = true;
930 while (!job_is_cancelled(&s->common.job) && !s->should_complete) {
931 job_yield(&s->common.job);
932 }
933 s->common.job.cancelled = false;
934 goto immediate_exit;
935 }
936
937 length = DIV_ROUND_UP(s->bdev_length, s->granularity);
938 s->in_flight_bitmap = bitmap_new(length);
939
940 /* If we have no backing file yet in the destination, we cannot let
941 * the destination do COW. Instead, we copy sectors around the
942 * dirty data if needed. We need a bitmap to do that.
943 */
944 bdrv_get_backing_filename(target_bs, backing_filename,
945 sizeof(backing_filename));
946 if (!bdrv_get_info(target_bs, &bdi) && bdi.cluster_size) {
947 s->target_cluster_size = bdi.cluster_size;
948 } else {
949 s->target_cluster_size = BDRV_SECTOR_SIZE;
950 }
951 if (backing_filename[0] && !bdrv_backing_chain_next(target_bs) &&
952 s->granularity < s->target_cluster_size) {
953 s->buf_size = MAX(s->buf_size, s->target_cluster_size);
954 s->cow_bitmap = bitmap_new(length);
955 }
956 s->max_iov = MIN(bs->bl.max_iov, target_bs->bl.max_iov);
957
958 s->buf = qemu_try_blockalign(bs, s->buf_size);
959 if (s->buf == NULL) {
960 ret = -ENOMEM;
961 goto immediate_exit;
962 }
963
964 mirror_free_init(s);
965
966 s->last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
967 if (!s->is_none_mode) {
968 ret = mirror_dirty_init(s);
969 if (ret < 0 || job_is_cancelled(&s->common.job)) {
970 goto immediate_exit;
971 }
972 }
973
974 assert(!s->dbi);
975 s->dbi = bdrv_dirty_iter_new(s->dirty_bitmap);
976 for (;;) {
977 uint64_t delay_ns = 0;
978 int64_t cnt, delta;
979 bool should_complete;
980
981 /* Do not start passive operations while there are active
982 * writes in progress */
983 while (s->in_active_write_counter) {
984 mirror_wait_for_any_operation(s, true);
985 }
986
987 if (s->ret < 0) {
988 ret = s->ret;
989 goto immediate_exit;
990 }
991
992 job_pause_point(&s->common.job);
993
994 cnt = bdrv_get_dirty_count(s->dirty_bitmap);
995 /* cnt is the number of dirty bytes remaining and s->bytes_in_flight is
996 * the number of bytes currently being processed; together those are
997 * the current remaining operation length */
998 job_progress_set_remaining(&s->common.job, s->bytes_in_flight + cnt);
999
1000 /* Note that even when no rate limit is applied we need to yield
1001 * periodically with no pending I/O so that bdrv_drain_all() returns.
1002 * We do so every BLKOCK_JOB_SLICE_TIME nanoseconds, or when there is
1003 * an error, or when the source is clean, whichever comes first. */
1004 delta = qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - s->last_pause_ns;
1005 if (delta < BLOCK_JOB_SLICE_TIME &&
1006 s->common.iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
1007 if (s->in_flight >= MAX_IN_FLIGHT || s->buf_free_count == 0 ||
1008 (cnt == 0 && s->in_flight > 0)) {
1009 trace_mirror_yield(s, cnt, s->buf_free_count, s->in_flight);
1010 mirror_wait_for_free_in_flight_slot(s);
1011 continue;
1012 } else if (cnt != 0) {
1013 delay_ns = mirror_iteration(s);
1014 }
1015 }
1016
1017 should_complete = false;
1018 if (s->in_flight == 0 && cnt == 0) {
1019 trace_mirror_before_flush(s);
1020 if (!s->synced) {
1021 if (mirror_flush(s) < 0) {
1022 /* Go check s->ret. */
1023 continue;
1024 }
1025 /* We're out of the streaming phase. From now on, if the job
1026 * is cancelled we will actually complete all pending I/O and
1027 * report completion. This way, block-job-cancel will leave
1028 * the target in a consistent state.
1029 */
1030 job_transition_to_ready(&s->common.job);
1031 s->synced = true;
1032 if (s->copy_mode != MIRROR_COPY_MODE_BACKGROUND) {
1033 s->actively_synced = true;
1034 }
1035 }
1036
1037 should_complete = s->should_complete ||
1038 job_is_cancelled(&s->common.job);
1039 cnt = bdrv_get_dirty_count(s->dirty_bitmap);
1040 }
1041
1042 if (cnt == 0 && should_complete) {
1043 /* The dirty bitmap is not updated while operations are pending.
1044 * If we're about to exit, wait for pending operations before
1045 * calling bdrv_get_dirty_count(bs), or we may exit while the
1046 * source has dirty data to copy!
1047 *
1048 * Note that I/O can be submitted by the guest while
1049 * mirror_populate runs, so pause it now. Before deciding
1050 * whether to switch to target check one last time if I/O has
1051 * come in the meanwhile, and if not flush the data to disk.
1052 */
1053 trace_mirror_before_drain(s, cnt);
1054
1055 s->in_drain = true;
1056 bdrv_drained_begin(bs);
1057 cnt = bdrv_get_dirty_count(s->dirty_bitmap);
1058 if (cnt > 0 || mirror_flush(s) < 0) {
1059 bdrv_drained_end(bs);
1060 s->in_drain = false;
1061 continue;
1062 }
1063
1064 /* The two disks are in sync. Exit and report successful
1065 * completion.
1066 */
1067 assert(QLIST_EMPTY(&bs->tracked_requests));
1068 s->common.job.cancelled = false;
1069 need_drain = false;
1070 break;
1071 }
1072
1073 ret = 0;
1074
1075 if (s->synced && !should_complete) {
1076 delay_ns = (s->in_flight == 0 &&
1077 cnt == 0 ? BLOCK_JOB_SLICE_TIME : 0);
1078 }
1079 trace_mirror_before_sleep(s, cnt, s->synced, delay_ns);
1080 job_sleep_ns(&s->common.job, delay_ns);
1081 if (job_is_cancelled(&s->common.job) &&
1082 (!s->synced || s->common.job.force_cancel))
1083 {
1084 break;
1085 }
1086 s->last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
1087 }
1088
1089 immediate_exit:
1090 if (s->in_flight > 0) {
1091 /* We get here only if something went wrong. Either the job failed,
1092 * or it was cancelled prematurely so that we do not guarantee that
1093 * the target is a copy of the source.
1094 */
1095 assert(ret < 0 || ((s->common.job.force_cancel || !s->synced) &&
1096 job_is_cancelled(&s->common.job)));
1097 assert(need_drain);
1098 mirror_wait_for_all_io(s);
1099 }
1100
1101 assert(s->in_flight == 0);
1102 qemu_vfree(s->buf);
1103 g_free(s->cow_bitmap);
1104 g_free(s->in_flight_bitmap);
1105 bdrv_dirty_iter_free(s->dbi);
1106
1107 if (need_drain) {
1108 s->in_drain = true;
1109 bdrv_drained_begin(bs);
1110 }
1111
1112 return ret;
1113 }
1114
1115 static void mirror_complete(Job *job, Error **errp)
1116 {
1117 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common.job);
1118
1119 if (!s->synced) {
1120 error_setg(errp, "The active block job '%s' cannot be completed",
1121 job->id);
1122 return;
1123 }
1124
1125 /* block all operations on to_replace bs */
1126 if (s->replaces) {
1127 AioContext *replace_aio_context;
1128
1129 s->to_replace = bdrv_find_node(s->replaces);
1130 if (!s->to_replace) {
1131 error_setg(errp, "Node name '%s' not found", s->replaces);
1132 return;
1133 }
1134
1135 replace_aio_context = bdrv_get_aio_context(s->to_replace);
1136 aio_context_acquire(replace_aio_context);
1137
1138 /* TODO Translate this into permission system. Current definition of
1139 * GRAPH_MOD would require to request it for the parents; they might
1140 * not even be BlockDriverStates, however, so a BdrvChild can't address
1141 * them. May need redefinition of GRAPH_MOD. */
1142 error_setg(&s->replace_blocker,
1143 "block device is in use by block-job-complete");
1144 bdrv_op_block_all(s->to_replace, s->replace_blocker);
1145 bdrv_ref(s->to_replace);
1146
1147 aio_context_release(replace_aio_context);
1148 }
1149
1150 s->should_complete = true;
1151
1152 /* If the job is paused, it will be re-entered when it is resumed */
1153 if (!job->paused) {
1154 job_enter(job);
1155 }
1156 }
1157
1158 static void coroutine_fn mirror_pause(Job *job)
1159 {
1160 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common.job);
1161
1162 mirror_wait_for_all_io(s);
1163 }
1164
1165 static bool mirror_drained_poll(BlockJob *job)
1166 {
1167 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common);
1168
1169 /* If the job isn't paused nor cancelled, we can't be sure that it won't
1170 * issue more requests. We make an exception if we've reached this point
1171 * from one of our own drain sections, to avoid a deadlock waiting for
1172 * ourselves.
1173 */
1174 if (!s->common.job.paused && !s->common.job.cancelled && !s->in_drain) {
1175 return true;
1176 }
1177
1178 return !!s->in_flight;
1179 }
1180
1181 static void mirror_cancel(Job *job, bool force)
1182 {
1183 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common.job);
1184 BlockDriverState *target = blk_bs(s->target);
1185
1186 if (force || !job_is_ready(job)) {
1187 bdrv_cancel_in_flight(target);
1188 }
1189 }
1190
1191 static const BlockJobDriver mirror_job_driver = {
1192 .job_driver = {
1193 .instance_size = sizeof(MirrorBlockJob),
1194 .job_type = JOB_TYPE_MIRROR,
1195 .free = block_job_free,
1196 .user_resume = block_job_user_resume,
1197 .run = mirror_run,
1198 .prepare = mirror_prepare,
1199 .abort = mirror_abort,
1200 .pause = mirror_pause,
1201 .complete = mirror_complete,
1202 .cancel = mirror_cancel,
1203 },
1204 .drained_poll = mirror_drained_poll,
1205 };
1206
1207 static const BlockJobDriver commit_active_job_driver = {
1208 .job_driver = {
1209 .instance_size = sizeof(MirrorBlockJob),
1210 .job_type = JOB_TYPE_COMMIT,
1211 .free = block_job_free,
1212 .user_resume = block_job_user_resume,
1213 .run = mirror_run,
1214 .prepare = mirror_prepare,
1215 .abort = mirror_abort,
1216 .pause = mirror_pause,
1217 .complete = mirror_complete,
1218 },
1219 .drained_poll = mirror_drained_poll,
1220 };
1221
1222 static void coroutine_fn
1223 do_sync_target_write(MirrorBlockJob *job, MirrorMethod method,
1224 uint64_t offset, uint64_t bytes,
1225 QEMUIOVector *qiov, int flags)
1226 {
1227 int ret;
1228 size_t qiov_offset = 0;
1229 int64_t bitmap_offset, bitmap_end;
1230
1231 if (!QEMU_IS_ALIGNED(offset, job->granularity) &&
1232 bdrv_dirty_bitmap_get(job->dirty_bitmap, offset))
1233 {
1234 /*
1235 * Dirty unaligned padding: ignore it.
1236 *
1237 * Reasoning:
1238 * 1. If we copy it, we can't reset corresponding bit in
1239 * dirty_bitmap as there may be some "dirty" bytes still not
1240 * copied.
1241 * 2. It's already dirty, so skipping it we don't diverge mirror
1242 * progress.
1243 *
1244 * Note, that because of this, guest write may have no contribution
1245 * into mirror converge, but that's not bad, as we have background
1246 * process of mirroring. If under some bad circumstances (high guest
1247 * IO load) background process starve, we will not converge anyway,
1248 * even if each write will contribute, as guest is not guaranteed to
1249 * rewrite the whole disk.
1250 */
1251 qiov_offset = QEMU_ALIGN_UP(offset, job->granularity) - offset;
1252 if (bytes <= qiov_offset) {
1253 /* nothing to do after shrink */
1254 return;
1255 }
1256 offset += qiov_offset;
1257 bytes -= qiov_offset;
1258 }
1259
1260 if (!QEMU_IS_ALIGNED(offset + bytes, job->granularity) &&
1261 bdrv_dirty_bitmap_get(job->dirty_bitmap, offset + bytes - 1))
1262 {
1263 uint64_t tail = (offset + bytes) % job->granularity;
1264
1265 if (bytes <= tail) {
1266 /* nothing to do after shrink */
1267 return;
1268 }
1269 bytes -= tail;
1270 }
1271
1272 /*
1273 * Tails are either clean or shrunk, so for bitmap resetting
1274 * we safely align the range down.
1275 */
1276 bitmap_offset = QEMU_ALIGN_UP(offset, job->granularity);
1277 bitmap_end = QEMU_ALIGN_DOWN(offset + bytes, job->granularity);
1278 if (bitmap_offset < bitmap_end) {
1279 bdrv_reset_dirty_bitmap(job->dirty_bitmap, bitmap_offset,
1280 bitmap_end - bitmap_offset);
1281 }
1282
1283 job_progress_increase_remaining(&job->common.job, bytes);
1284
1285 switch (method) {
1286 case MIRROR_METHOD_COPY:
1287 ret = blk_co_pwritev_part(job->target, offset, bytes,
1288 qiov, qiov_offset, flags);
1289 break;
1290
1291 case MIRROR_METHOD_ZERO:
1292 assert(!qiov);
1293 ret = blk_co_pwrite_zeroes(job->target, offset, bytes, flags);
1294 break;
1295
1296 case MIRROR_METHOD_DISCARD:
1297 assert(!qiov);
1298 ret = blk_co_pdiscard(job->target, offset, bytes);
1299 break;
1300
1301 default:
1302 abort();
1303 }
1304
1305 if (ret >= 0) {
1306 job_progress_update(&job->common.job, bytes);
1307 } else {
1308 BlockErrorAction action;
1309
1310 /*
1311 * We failed, so we should mark dirty the whole area, aligned up.
1312 * Note that we don't care about shrunk tails if any: they were dirty
1313 * at function start, and they must be still dirty, as we've locked
1314 * the region for in-flight op.
1315 */
1316 bitmap_offset = QEMU_ALIGN_DOWN(offset, job->granularity);
1317 bitmap_end = QEMU_ALIGN_UP(offset + bytes, job->granularity);
1318 bdrv_set_dirty_bitmap(job->dirty_bitmap, bitmap_offset,
1319 bitmap_end - bitmap_offset);
1320 job->actively_synced = false;
1321
1322 action = mirror_error_action(job, false, -ret);
1323 if (action == BLOCK_ERROR_ACTION_REPORT) {
1324 if (!job->ret) {
1325 job->ret = ret;
1326 }
1327 }
1328 }
1329 }
1330
1331 static MirrorOp *coroutine_fn active_write_prepare(MirrorBlockJob *s,
1332 uint64_t offset,
1333 uint64_t bytes)
1334 {
1335 MirrorOp *op;
1336 uint64_t start_chunk = offset / s->granularity;
1337 uint64_t end_chunk = DIV_ROUND_UP(offset + bytes, s->granularity);
1338
1339 op = g_new(MirrorOp, 1);
1340 *op = (MirrorOp){
1341 .s = s,
1342 .offset = offset,
1343 .bytes = bytes,
1344 .is_active_write = true,
1345 .is_in_flight = true,
1346 };
1347 qemu_co_queue_init(&op->waiting_requests);
1348 QTAILQ_INSERT_TAIL(&s->ops_in_flight, op, next);
1349
1350 s->in_active_write_counter++;
1351
1352 mirror_wait_on_conflicts(op, s, offset, bytes);
1353
1354 bitmap_set(s->in_flight_bitmap, start_chunk, end_chunk - start_chunk);
1355
1356 return op;
1357 }
1358
1359 static void coroutine_fn active_write_settle(MirrorOp *op)
1360 {
1361 uint64_t start_chunk = op->offset / op->s->granularity;
1362 uint64_t end_chunk = DIV_ROUND_UP(op->offset + op->bytes,
1363 op->s->granularity);
1364
1365 if (!--op->s->in_active_write_counter && op->s->actively_synced) {
1366 BdrvChild *source = op->s->mirror_top_bs->backing;
1367
1368 if (QLIST_FIRST(&source->bs->parents) == source &&
1369 QLIST_NEXT(source, next_parent) == NULL)
1370 {
1371 /* Assert that we are back in sync once all active write
1372 * operations are settled.
1373 * Note that we can only assert this if the mirror node
1374 * is the source node's only parent. */
1375 assert(!bdrv_get_dirty_count(op->s->dirty_bitmap));
1376 }
1377 }
1378 bitmap_clear(op->s->in_flight_bitmap, start_chunk, end_chunk - start_chunk);
1379 QTAILQ_REMOVE(&op->s->ops_in_flight, op, next);
1380 qemu_co_queue_restart_all(&op->waiting_requests);
1381 g_free(op);
1382 }
1383
1384 static int coroutine_fn bdrv_mirror_top_preadv(BlockDriverState *bs,
1385 uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags)
1386 {
1387 return bdrv_co_preadv(bs->backing, offset, bytes, qiov, flags);
1388 }
1389
1390 static int coroutine_fn bdrv_mirror_top_do_write(BlockDriverState *bs,
1391 MirrorMethod method, uint64_t offset, uint64_t bytes, QEMUIOVector *qiov,
1392 int flags)
1393 {
1394 MirrorOp *op = NULL;
1395 MirrorBDSOpaque *s = bs->opaque;
1396 int ret = 0;
1397 bool copy_to_target;
1398
1399 copy_to_target = s->job->ret >= 0 &&
1400 s->job->copy_mode == MIRROR_COPY_MODE_WRITE_BLOCKING;
1401
1402 if (copy_to_target) {
1403 op = active_write_prepare(s->job, offset, bytes);
1404 }
1405
1406 switch (method) {
1407 case MIRROR_METHOD_COPY:
1408 ret = bdrv_co_pwritev(bs->backing, offset, bytes, qiov, flags);
1409 break;
1410
1411 case MIRROR_METHOD_ZERO:
1412 ret = bdrv_co_pwrite_zeroes(bs->backing, offset, bytes, flags);
1413 break;
1414
1415 case MIRROR_METHOD_DISCARD:
1416 ret = bdrv_co_pdiscard(bs->backing, offset, bytes);
1417 break;
1418
1419 default:
1420 abort();
1421 }
1422
1423 if (ret < 0) {
1424 goto out;
1425 }
1426
1427 if (copy_to_target) {
1428 do_sync_target_write(s->job, method, offset, bytes, qiov, flags);
1429 }
1430
1431 out:
1432 if (copy_to_target) {
1433 active_write_settle(op);
1434 }
1435 return ret;
1436 }
1437
1438 static int coroutine_fn bdrv_mirror_top_pwritev(BlockDriverState *bs,
1439 uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags)
1440 {
1441 MirrorBDSOpaque *s = bs->opaque;
1442 QEMUIOVector bounce_qiov;
1443 void *bounce_buf;
1444 int ret = 0;
1445 bool copy_to_target;
1446
1447 copy_to_target = s->job->ret >= 0 &&
1448 s->job->copy_mode == MIRROR_COPY_MODE_WRITE_BLOCKING;
1449
1450 if (copy_to_target) {
1451 /* The guest might concurrently modify the data to write; but
1452 * the data on source and destination must match, so we have
1453 * to use a bounce buffer if we are going to write to the
1454 * target now. */
1455 bounce_buf = qemu_blockalign(bs, bytes);
1456 iov_to_buf_full(qiov->iov, qiov->niov, 0, bounce_buf, bytes);
1457
1458 qemu_iovec_init(&bounce_qiov, 1);
1459 qemu_iovec_add(&bounce_qiov, bounce_buf, bytes);
1460 qiov = &bounce_qiov;
1461 }
1462
1463 ret = bdrv_mirror_top_do_write(bs, MIRROR_METHOD_COPY, offset, bytes, qiov,
1464 flags);
1465
1466 if (copy_to_target) {
1467 qemu_iovec_destroy(&bounce_qiov);
1468 qemu_vfree(bounce_buf);
1469 }
1470
1471 return ret;
1472 }
1473
1474 static int coroutine_fn bdrv_mirror_top_flush(BlockDriverState *bs)
1475 {
1476 if (bs->backing == NULL) {
1477 /* we can be here after failed bdrv_append in mirror_start_job */
1478 return 0;
1479 }
1480 return bdrv_co_flush(bs->backing->bs);
1481 }
1482
1483 static int coroutine_fn bdrv_mirror_top_pwrite_zeroes(BlockDriverState *bs,
1484 int64_t offset, int bytes, BdrvRequestFlags flags)
1485 {
1486 return bdrv_mirror_top_do_write(bs, MIRROR_METHOD_ZERO, offset, bytes, NULL,
1487 flags);
1488 }
1489
1490 static int coroutine_fn bdrv_mirror_top_pdiscard(BlockDriverState *bs,
1491 int64_t offset, int bytes)
1492 {
1493 return bdrv_mirror_top_do_write(bs, MIRROR_METHOD_DISCARD, offset, bytes,
1494 NULL, 0);
1495 }
1496
1497 static void bdrv_mirror_top_refresh_filename(BlockDriverState *bs)
1498 {
1499 if (bs->backing == NULL) {
1500 /* we can be here after failed bdrv_attach_child in
1501 * bdrv_set_backing_hd */
1502 return;
1503 }
1504 pstrcpy(bs->exact_filename, sizeof(bs->exact_filename),
1505 bs->backing->bs->filename);
1506 }
1507
1508 static void bdrv_mirror_top_child_perm(BlockDriverState *bs, BdrvChild *c,
1509 BdrvChildRole role,
1510 BlockReopenQueue *reopen_queue,
1511 uint64_t perm, uint64_t shared,
1512 uint64_t *nperm, uint64_t *nshared)
1513 {
1514 MirrorBDSOpaque *s = bs->opaque;
1515
1516 if (s->stop) {
1517 /*
1518 * If the job is to be stopped, we do not need to forward
1519 * anything to the real image.
1520 */
1521 *nperm = 0;
1522 *nshared = BLK_PERM_ALL;
1523 return;
1524 }
1525
1526 bdrv_default_perms(bs, c, role, reopen_queue,
1527 perm, shared, nperm, nshared);
1528
1529 if (s->is_commit) {
1530 /*
1531 * For commit jobs, we cannot take CONSISTENT_READ, because
1532 * that permission is unshared for everything above the base
1533 * node (except for filters on the base node).
1534 * We also have to force-share the WRITE permission, or
1535 * otherwise we would block ourselves at the base node (if
1536 * writes are blocked for a node, they are also blocked for
1537 * its backing file).
1538 * (We could also share RESIZE, because it may be needed for
1539 * the target if its size is less than the top node's; but
1540 * bdrv_default_perms_for_cow() automatically shares RESIZE
1541 * for backing nodes if WRITE is shared, so there is no need
1542 * to do it here.)
1543 */
1544 *nperm &= ~BLK_PERM_CONSISTENT_READ;
1545 *nshared |= BLK_PERM_WRITE;
1546 }
1547 }
1548
1549 /* Dummy node that provides consistent read to its users without requiring it
1550 * from its backing file and that allows writes on the backing file chain. */
1551 static BlockDriver bdrv_mirror_top = {
1552 .format_name = "mirror_top",
1553 .bdrv_co_preadv = bdrv_mirror_top_preadv,
1554 .bdrv_co_pwritev = bdrv_mirror_top_pwritev,
1555 .bdrv_co_pwrite_zeroes = bdrv_mirror_top_pwrite_zeroes,
1556 .bdrv_co_pdiscard = bdrv_mirror_top_pdiscard,
1557 .bdrv_co_flush = bdrv_mirror_top_flush,
1558 .bdrv_refresh_filename = bdrv_mirror_top_refresh_filename,
1559 .bdrv_child_perm = bdrv_mirror_top_child_perm,
1560
1561 .is_filter = true,
1562 };
1563
1564 static BlockJob *mirror_start_job(
1565 const char *job_id, BlockDriverState *bs,
1566 int creation_flags, BlockDriverState *target,
1567 const char *replaces, int64_t speed,
1568 uint32_t granularity, int64_t buf_size,
1569 BlockMirrorBackingMode backing_mode,
1570 bool zero_target,
1571 BlockdevOnError on_source_error,
1572 BlockdevOnError on_target_error,
1573 bool unmap,
1574 BlockCompletionFunc *cb,
1575 void *opaque,
1576 const BlockJobDriver *driver,
1577 bool is_none_mode, BlockDriverState *base,
1578 bool auto_complete, const char *filter_node_name,
1579 bool is_mirror, MirrorCopyMode copy_mode,
1580 Error **errp)
1581 {
1582 MirrorBlockJob *s;
1583 MirrorBDSOpaque *bs_opaque;
1584 BlockDriverState *mirror_top_bs;
1585 bool target_is_backing;
1586 uint64_t target_perms, target_shared_perms;
1587 int ret;
1588
1589 if (granularity == 0) {
1590 granularity = bdrv_get_default_bitmap_granularity(target);
1591 }
1592
1593 assert(is_power_of_2(granularity));
1594
1595 if (buf_size < 0) {
1596 error_setg(errp, "Invalid parameter 'buf-size'");
1597 return NULL;
1598 }
1599
1600 if (buf_size == 0) {
1601 buf_size = DEFAULT_MIRROR_BUF_SIZE;
1602 }
1603
1604 if (bdrv_skip_filters(bs) == bdrv_skip_filters(target)) {
1605 error_setg(errp, "Can't mirror node into itself");
1606 return NULL;
1607 }
1608
1609 target_is_backing = bdrv_chain_contains(bs, target);
1610
1611 /* In the case of active commit, add dummy driver to provide consistent
1612 * reads on the top, while disabling it in the intermediate nodes, and make
1613 * the backing chain writable. */
1614 mirror_top_bs = bdrv_new_open_driver(&bdrv_mirror_top, filter_node_name,
1615 BDRV_O_RDWR, errp);
1616 if (mirror_top_bs == NULL) {
1617 return NULL;
1618 }
1619 if (!filter_node_name) {
1620 mirror_top_bs->implicit = true;
1621 }
1622
1623 /* So that we can always drop this node */
1624 mirror_top_bs->never_freeze = true;
1625
1626 mirror_top_bs->total_sectors = bs->total_sectors;
1627 mirror_top_bs->supported_write_flags = BDRV_REQ_WRITE_UNCHANGED;
1628 mirror_top_bs->supported_zero_flags = BDRV_REQ_WRITE_UNCHANGED |
1629 BDRV_REQ_NO_FALLBACK;
1630 bs_opaque = g_new0(MirrorBDSOpaque, 1);
1631 mirror_top_bs->opaque = bs_opaque;
1632
1633 bs_opaque->is_commit = target_is_backing;
1634
1635 bdrv_drained_begin(bs);
1636 ret = bdrv_append(mirror_top_bs, bs, errp);
1637 bdrv_drained_end(bs);
1638
1639 if (ret < 0) {
1640 bdrv_unref(mirror_top_bs);
1641 return NULL;
1642 }
1643
1644 /* Make sure that the source is not resized while the job is running */
1645 s = block_job_create(job_id, driver, NULL, mirror_top_bs,
1646 BLK_PERM_CONSISTENT_READ,
1647 BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED |
1648 BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD, speed,
1649 creation_flags, cb, opaque, errp);
1650 if (!s) {
1651 goto fail;
1652 }
1653 bs_opaque->job = s;
1654
1655 /* The block job now has a reference to this node */
1656 bdrv_unref(mirror_top_bs);
1657
1658 s->mirror_top_bs = mirror_top_bs;
1659
1660 /* No resize for the target either; while the mirror is still running, a
1661 * consistent read isn't necessarily possible. We could possibly allow
1662 * writes and graph modifications, though it would likely defeat the
1663 * purpose of a mirror, so leave them blocked for now.
1664 *
1665 * In the case of active commit, things look a bit different, though,
1666 * because the target is an already populated backing file in active use.
1667 * We can allow anything except resize there.*/
1668
1669 target_perms = BLK_PERM_WRITE;
1670 target_shared_perms = BLK_PERM_WRITE_UNCHANGED;
1671
1672 if (target_is_backing) {
1673 int64_t bs_size, target_size;
1674 bs_size = bdrv_getlength(bs);
1675 if (bs_size < 0) {
1676 error_setg_errno(errp, -bs_size,
1677 "Could not inquire top image size");
1678 goto fail;
1679 }
1680
1681 target_size = bdrv_getlength(target);
1682 if (target_size < 0) {
1683 error_setg_errno(errp, -target_size,
1684 "Could not inquire base image size");
1685 goto fail;
1686 }
1687
1688 if (target_size < bs_size) {
1689 target_perms |= BLK_PERM_RESIZE;
1690 }
1691
1692 target_shared_perms |= BLK_PERM_CONSISTENT_READ
1693 | BLK_PERM_WRITE
1694 | BLK_PERM_GRAPH_MOD;
1695 } else if (bdrv_chain_contains(bs, bdrv_skip_filters(target))) {
1696 /*
1697 * We may want to allow this in the future, but it would
1698 * require taking some extra care.
1699 */
1700 error_setg(errp, "Cannot mirror to a filter on top of a node in the "
1701 "source's backing chain");
1702 goto fail;
1703 }
1704
1705 if (backing_mode != MIRROR_LEAVE_BACKING_CHAIN) {
1706 target_perms |= BLK_PERM_GRAPH_MOD;
1707 }
1708
1709 s->target = blk_new(s->common.job.aio_context,
1710 target_perms, target_shared_perms);
1711 ret = blk_insert_bs(s->target, target, errp);
1712 if (ret < 0) {
1713 goto fail;
1714 }
1715 if (is_mirror) {
1716 /* XXX: Mirror target could be a NBD server of target QEMU in the case
1717 * of non-shared block migration. To allow migration completion, we
1718 * have to allow "inactivate" of the target BB. When that happens, we
1719 * know the job is drained, and the vcpus are stopped, so no write
1720 * operation will be performed. Block layer already has assertions to
1721 * ensure that. */
1722 blk_set_force_allow_inactivate(s->target);
1723 }
1724 blk_set_allow_aio_context_change(s->target, true);
1725 blk_set_disable_request_queuing(s->target, true);
1726
1727 s->replaces = g_strdup(replaces);
1728 s->on_source_error = on_source_error;
1729 s->on_target_error = on_target_error;
1730 s->is_none_mode = is_none_mode;
1731 s->backing_mode = backing_mode;
1732 s->zero_target = zero_target;
1733 s->copy_mode = copy_mode;
1734 s->base = base;
1735 s->base_overlay = bdrv_find_overlay(bs, base);
1736 s->granularity = granularity;
1737 s->buf_size = ROUND_UP(buf_size, granularity);
1738 s->unmap = unmap;
1739 if (auto_complete) {
1740 s->should_complete = true;
1741 }
1742
1743 s->dirty_bitmap = bdrv_create_dirty_bitmap(bs, granularity, NULL, errp);
1744 if (!s->dirty_bitmap) {
1745 goto fail;
1746 }
1747 if (s->copy_mode == MIRROR_COPY_MODE_WRITE_BLOCKING) {
1748 bdrv_disable_dirty_bitmap(s->dirty_bitmap);
1749 }
1750
1751 ret = block_job_add_bdrv(&s->common, "source", bs, 0,
1752 BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE |
1753 BLK_PERM_CONSISTENT_READ,
1754 errp);
1755 if (ret < 0) {
1756 goto fail;
1757 }
1758
1759 /* Required permissions are already taken with blk_new() */
1760 block_job_add_bdrv(&s->common, "target", target, 0, BLK_PERM_ALL,
1761 &error_abort);
1762
1763 /* In commit_active_start() all intermediate nodes disappear, so
1764 * any jobs in them must be blocked */
1765 if (target_is_backing) {
1766 BlockDriverState *iter, *filtered_target;
1767 uint64_t iter_shared_perms;
1768
1769 /*
1770 * The topmost node with
1771 * bdrv_skip_filters(filtered_target) == bdrv_skip_filters(target)
1772 */
1773 filtered_target = bdrv_cow_bs(bdrv_find_overlay(bs, target));
1774
1775 assert(bdrv_skip_filters(filtered_target) ==
1776 bdrv_skip_filters(target));
1777
1778 /*
1779 * XXX BLK_PERM_WRITE needs to be allowed so we don't block
1780 * ourselves at s->base (if writes are blocked for a node, they are
1781 * also blocked for its backing file). The other options would be a
1782 * second filter driver above s->base (== target).
1783 */
1784 iter_shared_perms = BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE;
1785
1786 for (iter = bdrv_filter_or_cow_bs(bs); iter != target;
1787 iter = bdrv_filter_or_cow_bs(iter))
1788 {
1789 if (iter == filtered_target) {
1790 /*
1791 * From here on, all nodes are filters on the base.
1792 * This allows us to share BLK_PERM_CONSISTENT_READ.
1793 */
1794 iter_shared_perms |= BLK_PERM_CONSISTENT_READ;
1795 }
1796
1797 ret = block_job_add_bdrv(&s->common, "intermediate node", iter, 0,
1798 iter_shared_perms, errp);
1799 if (ret < 0) {
1800 goto fail;
1801 }
1802 }
1803
1804 if (bdrv_freeze_backing_chain(mirror_top_bs, target, errp) < 0) {
1805 goto fail;
1806 }
1807 }
1808
1809 QTAILQ_INIT(&s->ops_in_flight);
1810
1811 trace_mirror_start(bs, s, opaque);
1812 job_start(&s->common.job);
1813
1814 return &s->common;
1815
1816 fail:
1817 if (s) {
1818 /* Make sure this BDS does not go away until we have completed the graph
1819 * changes below */
1820 bdrv_ref(mirror_top_bs);
1821
1822 g_free(s->replaces);
1823 blk_unref(s->target);
1824 bs_opaque->job = NULL;
1825 if (s->dirty_bitmap) {
1826 bdrv_release_dirty_bitmap(s->dirty_bitmap);
1827 }
1828 job_early_fail(&s->common.job);
1829 }
1830
1831 bs_opaque->stop = true;
1832 bdrv_child_refresh_perms(mirror_top_bs, mirror_top_bs->backing,
1833 &error_abort);
1834 bdrv_replace_node(mirror_top_bs, mirror_top_bs->backing->bs, &error_abort);
1835
1836 bdrv_unref(mirror_top_bs);
1837
1838 return NULL;
1839 }
1840
1841 void mirror_start(const char *job_id, BlockDriverState *bs,
1842 BlockDriverState *target, const char *replaces,
1843 int creation_flags, int64_t speed,
1844 uint32_t granularity, int64_t buf_size,
1845 MirrorSyncMode mode, BlockMirrorBackingMode backing_mode,
1846 bool zero_target,
1847 BlockdevOnError on_source_error,
1848 BlockdevOnError on_target_error,
1849 bool unmap, const char *filter_node_name,
1850 MirrorCopyMode copy_mode, Error **errp)
1851 {
1852 bool is_none_mode;
1853 BlockDriverState *base;
1854
1855 if ((mode == MIRROR_SYNC_MODE_INCREMENTAL) ||
1856 (mode == MIRROR_SYNC_MODE_BITMAP)) {
1857 error_setg(errp, "Sync mode '%s' not supported",
1858 MirrorSyncMode_str(mode));
1859 return;
1860 }
1861 is_none_mode = mode == MIRROR_SYNC_MODE_NONE;
1862 base = mode == MIRROR_SYNC_MODE_TOP ? bdrv_backing_chain_next(bs) : NULL;
1863 mirror_start_job(job_id, bs, creation_flags, target, replaces,
1864 speed, granularity, buf_size, backing_mode, zero_target,
1865 on_source_error, on_target_error, unmap, NULL, NULL,
1866 &mirror_job_driver, is_none_mode, base, false,
1867 filter_node_name, true, copy_mode, errp);
1868 }
1869
1870 BlockJob *commit_active_start(const char *job_id, BlockDriverState *bs,
1871 BlockDriverState *base, int creation_flags,
1872 int64_t speed, BlockdevOnError on_error,
1873 const char *filter_node_name,
1874 BlockCompletionFunc *cb, void *opaque,
1875 bool auto_complete, Error **errp)
1876 {
1877 bool base_read_only;
1878 BlockJob *job;
1879
1880 base_read_only = bdrv_is_read_only(base);
1881
1882 if (base_read_only) {
1883 if (bdrv_reopen_set_read_only(base, false, errp) < 0) {
1884 return NULL;
1885 }
1886 }
1887
1888 job = mirror_start_job(
1889 job_id, bs, creation_flags, base, NULL, speed, 0, 0,
1890 MIRROR_LEAVE_BACKING_CHAIN, false,
1891 on_error, on_error, true, cb, opaque,
1892 &commit_active_job_driver, false, base, auto_complete,
1893 filter_node_name, false, MIRROR_COPY_MODE_BACKGROUND,
1894 errp);
1895 if (!job) {
1896 goto error_restore_flags;
1897 }
1898
1899 return job;
1900
1901 error_restore_flags:
1902 /* ignore error and errp for bdrv_reopen, because we want to propagate
1903 * the original error */
1904 if (base_read_only) {
1905 bdrv_reopen_set_read_only(base, true, NULL);
1906 }
1907 return NULL;
1908 }