Merge remote-tracking branch 'remotes/kraxel/tags/pull-vga-20170103-1' into staging
[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 "trace.h"
16 #include "block/blockjob_int.h"
17 #include "block/block_int.h"
18 #include "sysemu/block-backend.h"
19 #include "qapi/error.h"
20 #include "qapi/qmp/qerror.h"
21 #include "qemu/ratelimit.h"
22 #include "qemu/bitmap.h"
23
24 #define SLICE_TIME 100000000ULL /* ns */
25 #define MAX_IN_FLIGHT 16
26 #define MAX_IO_SECTORS ((1 << 20) >> BDRV_SECTOR_BITS) /* 1 Mb */
27 #define DEFAULT_MIRROR_BUF_SIZE \
28 (MAX_IN_FLIGHT * MAX_IO_SECTORS * BDRV_SECTOR_SIZE)
29
30 /* The mirroring buffer is a list of granularity-sized chunks.
31 * Free chunks are organized in a list.
32 */
33 typedef struct MirrorBuffer {
34 QSIMPLEQ_ENTRY(MirrorBuffer) next;
35 } MirrorBuffer;
36
37 typedef struct MirrorBlockJob {
38 BlockJob common;
39 RateLimit limit;
40 BlockBackend *target;
41 BlockDriverState *base;
42 /* The name of the graph node to replace */
43 char *replaces;
44 /* The BDS to replace */
45 BlockDriverState *to_replace;
46 /* Used to block operations on the drive-mirror-replace target */
47 Error *replace_blocker;
48 bool is_none_mode;
49 BlockMirrorBackingMode backing_mode;
50 BlockdevOnError on_source_error, on_target_error;
51 bool synced;
52 bool should_complete;
53 int64_t granularity;
54 size_t buf_size;
55 int64_t bdev_length;
56 unsigned long *cow_bitmap;
57 BdrvDirtyBitmap *dirty_bitmap;
58 BdrvDirtyBitmapIter *dbi;
59 uint8_t *buf;
60 QSIMPLEQ_HEAD(, MirrorBuffer) buf_free;
61 int buf_free_count;
62
63 uint64_t last_pause_ns;
64 unsigned long *in_flight_bitmap;
65 int in_flight;
66 int64_t sectors_in_flight;
67 int ret;
68 bool unmap;
69 bool waiting_for_io;
70 int target_cluster_sectors;
71 int max_iov;
72 } MirrorBlockJob;
73
74 typedef struct MirrorOp {
75 MirrorBlockJob *s;
76 QEMUIOVector qiov;
77 int64_t sector_num;
78 int nb_sectors;
79 } MirrorOp;
80
81 static BlockErrorAction mirror_error_action(MirrorBlockJob *s, bool read,
82 int error)
83 {
84 s->synced = false;
85 if (read) {
86 return block_job_error_action(&s->common, s->on_source_error,
87 true, error);
88 } else {
89 return block_job_error_action(&s->common, s->on_target_error,
90 false, error);
91 }
92 }
93
94 static void mirror_iteration_done(MirrorOp *op, int ret)
95 {
96 MirrorBlockJob *s = op->s;
97 struct iovec *iov;
98 int64_t chunk_num;
99 int i, nb_chunks, sectors_per_chunk;
100
101 trace_mirror_iteration_done(s, op->sector_num, op->nb_sectors, ret);
102
103 s->in_flight--;
104 s->sectors_in_flight -= op->nb_sectors;
105 iov = op->qiov.iov;
106 for (i = 0; i < op->qiov.niov; i++) {
107 MirrorBuffer *buf = (MirrorBuffer *) iov[i].iov_base;
108 QSIMPLEQ_INSERT_TAIL(&s->buf_free, buf, next);
109 s->buf_free_count++;
110 }
111
112 sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS;
113 chunk_num = op->sector_num / sectors_per_chunk;
114 nb_chunks = DIV_ROUND_UP(op->nb_sectors, sectors_per_chunk);
115 bitmap_clear(s->in_flight_bitmap, chunk_num, nb_chunks);
116 if (ret >= 0) {
117 if (s->cow_bitmap) {
118 bitmap_set(s->cow_bitmap, chunk_num, nb_chunks);
119 }
120 s->common.offset += (uint64_t)op->nb_sectors * BDRV_SECTOR_SIZE;
121 }
122
123 qemu_iovec_destroy(&op->qiov);
124 g_free(op);
125
126 if (s->waiting_for_io) {
127 qemu_coroutine_enter(s->common.co);
128 }
129 }
130
131 static void mirror_write_complete(void *opaque, int ret)
132 {
133 MirrorOp *op = opaque;
134 MirrorBlockJob *s = op->s;
135 if (ret < 0) {
136 BlockErrorAction action;
137
138 bdrv_set_dirty_bitmap(s->dirty_bitmap, op->sector_num, op->nb_sectors);
139 action = mirror_error_action(s, false, -ret);
140 if (action == BLOCK_ERROR_ACTION_REPORT && s->ret >= 0) {
141 s->ret = ret;
142 }
143 }
144 mirror_iteration_done(op, ret);
145 }
146
147 static void mirror_read_complete(void *opaque, int ret)
148 {
149 MirrorOp *op = opaque;
150 MirrorBlockJob *s = op->s;
151 if (ret < 0) {
152 BlockErrorAction action;
153
154 bdrv_set_dirty_bitmap(s->dirty_bitmap, op->sector_num, op->nb_sectors);
155 action = mirror_error_action(s, true, -ret);
156 if (action == BLOCK_ERROR_ACTION_REPORT && s->ret >= 0) {
157 s->ret = ret;
158 }
159
160 mirror_iteration_done(op, ret);
161 return;
162 }
163 blk_aio_pwritev(s->target, op->sector_num * BDRV_SECTOR_SIZE, &op->qiov,
164 0, mirror_write_complete, op);
165 }
166
167 static inline void mirror_clip_sectors(MirrorBlockJob *s,
168 int64_t sector_num,
169 int *nb_sectors)
170 {
171 *nb_sectors = MIN(*nb_sectors,
172 s->bdev_length / BDRV_SECTOR_SIZE - sector_num);
173 }
174
175 /* Round sector_num and/or nb_sectors to target cluster if COW is needed, and
176 * return the offset of the adjusted tail sector against original. */
177 static int mirror_cow_align(MirrorBlockJob *s,
178 int64_t *sector_num,
179 int *nb_sectors)
180 {
181 bool need_cow;
182 int ret = 0;
183 int chunk_sectors = s->granularity >> BDRV_SECTOR_BITS;
184 int64_t align_sector_num = *sector_num;
185 int align_nb_sectors = *nb_sectors;
186 int max_sectors = chunk_sectors * s->max_iov;
187
188 need_cow = !test_bit(*sector_num / chunk_sectors, s->cow_bitmap);
189 need_cow |= !test_bit((*sector_num + *nb_sectors - 1) / chunk_sectors,
190 s->cow_bitmap);
191 if (need_cow) {
192 bdrv_round_sectors_to_clusters(blk_bs(s->target), *sector_num,
193 *nb_sectors, &align_sector_num,
194 &align_nb_sectors);
195 }
196
197 if (align_nb_sectors > max_sectors) {
198 align_nb_sectors = max_sectors;
199 if (need_cow) {
200 align_nb_sectors = QEMU_ALIGN_DOWN(align_nb_sectors,
201 s->target_cluster_sectors);
202 }
203 }
204 /* Clipping may result in align_nb_sectors unaligned to chunk boundary, but
205 * that doesn't matter because it's already the end of source image. */
206 mirror_clip_sectors(s, align_sector_num, &align_nb_sectors);
207
208 ret = align_sector_num + align_nb_sectors - (*sector_num + *nb_sectors);
209 *sector_num = align_sector_num;
210 *nb_sectors = align_nb_sectors;
211 assert(ret >= 0);
212 return ret;
213 }
214
215 static inline void mirror_wait_for_io(MirrorBlockJob *s)
216 {
217 assert(!s->waiting_for_io);
218 s->waiting_for_io = true;
219 qemu_coroutine_yield();
220 s->waiting_for_io = false;
221 }
222
223 /* Submit async read while handling COW.
224 * Returns: The number of sectors copied after and including sector_num,
225 * excluding any sectors copied prior to sector_num due to alignment.
226 * This will be nb_sectors if no alignment is necessary, or
227 * (new_end - sector_num) if tail is rounded up or down due to
228 * alignment or buffer limit.
229 */
230 static int mirror_do_read(MirrorBlockJob *s, int64_t sector_num,
231 int nb_sectors)
232 {
233 BlockBackend *source = s->common.blk;
234 int sectors_per_chunk, nb_chunks;
235 int ret;
236 MirrorOp *op;
237 int max_sectors;
238
239 sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS;
240 max_sectors = sectors_per_chunk * s->max_iov;
241
242 /* We can only handle as much as buf_size at a time. */
243 nb_sectors = MIN(s->buf_size >> BDRV_SECTOR_BITS, nb_sectors);
244 nb_sectors = MIN(max_sectors, nb_sectors);
245 assert(nb_sectors);
246 ret = nb_sectors;
247
248 if (s->cow_bitmap) {
249 ret += mirror_cow_align(s, &sector_num, &nb_sectors);
250 }
251 assert(nb_sectors << BDRV_SECTOR_BITS <= s->buf_size);
252 /* The sector range must meet granularity because:
253 * 1) Caller passes in aligned values;
254 * 2) mirror_cow_align is used only when target cluster is larger. */
255 assert(!(sector_num % sectors_per_chunk));
256 nb_chunks = DIV_ROUND_UP(nb_sectors, sectors_per_chunk);
257
258 while (s->buf_free_count < nb_chunks) {
259 trace_mirror_yield_in_flight(s, sector_num, s->in_flight);
260 mirror_wait_for_io(s);
261 }
262
263 /* Allocate a MirrorOp that is used as an AIO callback. */
264 op = g_new(MirrorOp, 1);
265 op->s = s;
266 op->sector_num = sector_num;
267 op->nb_sectors = nb_sectors;
268
269 /* Now make a QEMUIOVector taking enough granularity-sized chunks
270 * from s->buf_free.
271 */
272 qemu_iovec_init(&op->qiov, nb_chunks);
273 while (nb_chunks-- > 0) {
274 MirrorBuffer *buf = QSIMPLEQ_FIRST(&s->buf_free);
275 size_t remaining = nb_sectors * BDRV_SECTOR_SIZE - op->qiov.size;
276
277 QSIMPLEQ_REMOVE_HEAD(&s->buf_free, next);
278 s->buf_free_count--;
279 qemu_iovec_add(&op->qiov, buf, MIN(s->granularity, remaining));
280 }
281
282 /* Copy the dirty cluster. */
283 s->in_flight++;
284 s->sectors_in_flight += nb_sectors;
285 trace_mirror_one_iteration(s, sector_num, nb_sectors);
286
287 blk_aio_preadv(source, sector_num * BDRV_SECTOR_SIZE, &op->qiov, 0,
288 mirror_read_complete, op);
289 return ret;
290 }
291
292 static void mirror_do_zero_or_discard(MirrorBlockJob *s,
293 int64_t sector_num,
294 int nb_sectors,
295 bool is_discard)
296 {
297 MirrorOp *op;
298
299 /* Allocate a MirrorOp that is used as an AIO callback. The qiov is zeroed
300 * so the freeing in mirror_iteration_done is nop. */
301 op = g_new0(MirrorOp, 1);
302 op->s = s;
303 op->sector_num = sector_num;
304 op->nb_sectors = nb_sectors;
305
306 s->in_flight++;
307 s->sectors_in_flight += nb_sectors;
308 if (is_discard) {
309 blk_aio_pdiscard(s->target, sector_num << BDRV_SECTOR_BITS,
310 op->nb_sectors << BDRV_SECTOR_BITS,
311 mirror_write_complete, op);
312 } else {
313 blk_aio_pwrite_zeroes(s->target, sector_num * BDRV_SECTOR_SIZE,
314 op->nb_sectors * BDRV_SECTOR_SIZE,
315 s->unmap ? BDRV_REQ_MAY_UNMAP : 0,
316 mirror_write_complete, op);
317 }
318 }
319
320 static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
321 {
322 BlockDriverState *source = blk_bs(s->common.blk);
323 int64_t sector_num, first_chunk;
324 uint64_t delay_ns = 0;
325 /* At least the first dirty chunk is mirrored in one iteration. */
326 int nb_chunks = 1;
327 int64_t end = s->bdev_length / BDRV_SECTOR_SIZE;
328 int sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS;
329 bool write_zeroes_ok = bdrv_can_write_zeroes_with_unmap(blk_bs(s->target));
330 int max_io_sectors = MAX((s->buf_size >> BDRV_SECTOR_BITS) / MAX_IN_FLIGHT,
331 MAX_IO_SECTORS);
332
333 sector_num = bdrv_dirty_iter_next(s->dbi);
334 if (sector_num < 0) {
335 bdrv_set_dirty_iter(s->dbi, 0);
336 sector_num = bdrv_dirty_iter_next(s->dbi);
337 trace_mirror_restart_iter(s, bdrv_get_dirty_count(s->dirty_bitmap));
338 assert(sector_num >= 0);
339 }
340
341 first_chunk = sector_num / sectors_per_chunk;
342 while (test_bit(first_chunk, s->in_flight_bitmap)) {
343 trace_mirror_yield_in_flight(s, sector_num, s->in_flight);
344 mirror_wait_for_io(s);
345 }
346
347 block_job_pause_point(&s->common);
348
349 /* Find the number of consective dirty chunks following the first dirty
350 * one, and wait for in flight requests in them. */
351 while (nb_chunks * sectors_per_chunk < (s->buf_size >> BDRV_SECTOR_BITS)) {
352 int64_t next_dirty;
353 int64_t next_sector = sector_num + nb_chunks * sectors_per_chunk;
354 int64_t next_chunk = next_sector / sectors_per_chunk;
355 if (next_sector >= end ||
356 !bdrv_get_dirty(source, s->dirty_bitmap, next_sector)) {
357 break;
358 }
359 if (test_bit(next_chunk, s->in_flight_bitmap)) {
360 break;
361 }
362
363 next_dirty = bdrv_dirty_iter_next(s->dbi);
364 if (next_dirty > next_sector || next_dirty < 0) {
365 /* The bitmap iterator's cache is stale, refresh it */
366 bdrv_set_dirty_iter(s->dbi, next_sector);
367 next_dirty = bdrv_dirty_iter_next(s->dbi);
368 }
369 assert(next_dirty == next_sector);
370 nb_chunks++;
371 }
372
373 /* Clear dirty bits before querying the block status, because
374 * calling bdrv_get_block_status_above could yield - if some blocks are
375 * marked dirty in this window, we need to know.
376 */
377 bdrv_reset_dirty_bitmap(s->dirty_bitmap, sector_num,
378 nb_chunks * sectors_per_chunk);
379 bitmap_set(s->in_flight_bitmap, sector_num / sectors_per_chunk, nb_chunks);
380 while (nb_chunks > 0 && sector_num < end) {
381 int ret;
382 int io_sectors, io_sectors_acct;
383 BlockDriverState *file;
384 enum MirrorMethod {
385 MIRROR_METHOD_COPY,
386 MIRROR_METHOD_ZERO,
387 MIRROR_METHOD_DISCARD
388 } mirror_method = MIRROR_METHOD_COPY;
389
390 assert(!(sector_num % sectors_per_chunk));
391 ret = bdrv_get_block_status_above(source, NULL, sector_num,
392 nb_chunks * sectors_per_chunk,
393 &io_sectors, &file);
394 if (ret < 0) {
395 io_sectors = MIN(nb_chunks * sectors_per_chunk, max_io_sectors);
396 } else if (ret & BDRV_BLOCK_DATA) {
397 io_sectors = MIN(io_sectors, max_io_sectors);
398 }
399
400 io_sectors -= io_sectors % sectors_per_chunk;
401 if (io_sectors < sectors_per_chunk) {
402 io_sectors = sectors_per_chunk;
403 } else if (ret >= 0 && !(ret & BDRV_BLOCK_DATA)) {
404 int64_t target_sector_num;
405 int target_nb_sectors;
406 bdrv_round_sectors_to_clusters(blk_bs(s->target), sector_num,
407 io_sectors, &target_sector_num,
408 &target_nb_sectors);
409 if (target_sector_num == sector_num &&
410 target_nb_sectors == io_sectors) {
411 mirror_method = ret & BDRV_BLOCK_ZERO ?
412 MIRROR_METHOD_ZERO :
413 MIRROR_METHOD_DISCARD;
414 }
415 }
416
417 while (s->in_flight >= MAX_IN_FLIGHT) {
418 trace_mirror_yield_in_flight(s, sector_num, s->in_flight);
419 mirror_wait_for_io(s);
420 }
421
422 if (s->ret < 0) {
423 return 0;
424 }
425
426 mirror_clip_sectors(s, sector_num, &io_sectors);
427 switch (mirror_method) {
428 case MIRROR_METHOD_COPY:
429 io_sectors = mirror_do_read(s, sector_num, io_sectors);
430 io_sectors_acct = io_sectors;
431 break;
432 case MIRROR_METHOD_ZERO:
433 case MIRROR_METHOD_DISCARD:
434 mirror_do_zero_or_discard(s, sector_num, io_sectors,
435 mirror_method == MIRROR_METHOD_DISCARD);
436 if (write_zeroes_ok) {
437 io_sectors_acct = 0;
438 } else {
439 io_sectors_acct = io_sectors;
440 }
441 break;
442 default:
443 abort();
444 }
445 assert(io_sectors);
446 sector_num += io_sectors;
447 nb_chunks -= DIV_ROUND_UP(io_sectors, sectors_per_chunk);
448 if (s->common.speed) {
449 delay_ns = ratelimit_calculate_delay(&s->limit, io_sectors_acct);
450 }
451 }
452 return delay_ns;
453 }
454
455 static void mirror_free_init(MirrorBlockJob *s)
456 {
457 int granularity = s->granularity;
458 size_t buf_size = s->buf_size;
459 uint8_t *buf = s->buf;
460
461 assert(s->buf_free_count == 0);
462 QSIMPLEQ_INIT(&s->buf_free);
463 while (buf_size != 0) {
464 MirrorBuffer *cur = (MirrorBuffer *)buf;
465 QSIMPLEQ_INSERT_TAIL(&s->buf_free, cur, next);
466 s->buf_free_count++;
467 buf_size -= granularity;
468 buf += granularity;
469 }
470 }
471
472 /* This is also used for the .pause callback. There is no matching
473 * mirror_resume() because mirror_run() will begin iterating again
474 * when the job is resumed.
475 */
476 static void mirror_wait_for_all_io(MirrorBlockJob *s)
477 {
478 while (s->in_flight > 0) {
479 mirror_wait_for_io(s);
480 }
481 }
482
483 typedef struct {
484 int ret;
485 } MirrorExitData;
486
487 static void mirror_exit(BlockJob *job, void *opaque)
488 {
489 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common);
490 MirrorExitData *data = opaque;
491 AioContext *replace_aio_context = NULL;
492 BlockDriverState *src = blk_bs(s->common.blk);
493 BlockDriverState *target_bs = blk_bs(s->target);
494
495 /* Make sure that the source BDS doesn't go away before we called
496 * block_job_completed(). */
497 bdrv_ref(src);
498
499 if (s->to_replace) {
500 replace_aio_context = bdrv_get_aio_context(s->to_replace);
501 aio_context_acquire(replace_aio_context);
502 }
503
504 if (s->should_complete && data->ret == 0) {
505 BlockDriverState *to_replace = src;
506 if (s->to_replace) {
507 to_replace = s->to_replace;
508 }
509
510 if (bdrv_get_flags(target_bs) != bdrv_get_flags(to_replace)) {
511 bdrv_reopen(target_bs, bdrv_get_flags(to_replace), NULL);
512 }
513
514 /* The mirror job has no requests in flight any more, but we need to
515 * drain potential other users of the BDS before changing the graph. */
516 bdrv_drained_begin(target_bs);
517 bdrv_replace_in_backing_chain(to_replace, target_bs);
518 bdrv_drained_end(target_bs);
519
520 /* We just changed the BDS the job BB refers to */
521 blk_remove_bs(job->blk);
522 blk_insert_bs(job->blk, src);
523 }
524 if (s->to_replace) {
525 bdrv_op_unblock_all(s->to_replace, s->replace_blocker);
526 error_free(s->replace_blocker);
527 bdrv_unref(s->to_replace);
528 }
529 if (replace_aio_context) {
530 aio_context_release(replace_aio_context);
531 }
532 g_free(s->replaces);
533 blk_unref(s->target);
534 s->target = NULL;
535 block_job_completed(&s->common, data->ret);
536 g_free(data);
537 bdrv_drained_end(src);
538 bdrv_unref(src);
539 }
540
541 static void mirror_throttle(MirrorBlockJob *s)
542 {
543 int64_t now = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
544
545 if (now - s->last_pause_ns > SLICE_TIME) {
546 s->last_pause_ns = now;
547 block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, 0);
548 } else {
549 block_job_pause_point(&s->common);
550 }
551 }
552
553 static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s)
554 {
555 int64_t sector_num, end;
556 BlockDriverState *base = s->base;
557 BlockDriverState *bs = blk_bs(s->common.blk);
558 BlockDriverState *target_bs = blk_bs(s->target);
559 int ret, n;
560
561 end = s->bdev_length / BDRV_SECTOR_SIZE;
562
563 if (base == NULL && !bdrv_has_zero_init(target_bs)) {
564 if (!bdrv_can_write_zeroes_with_unmap(target_bs)) {
565 bdrv_set_dirty_bitmap(s->dirty_bitmap, 0, end);
566 return 0;
567 }
568
569 for (sector_num = 0; sector_num < end; ) {
570 int nb_sectors = MIN(end - sector_num,
571 QEMU_ALIGN_DOWN(INT_MAX, s->granularity) >> BDRV_SECTOR_BITS);
572
573 mirror_throttle(s);
574
575 if (block_job_is_cancelled(&s->common)) {
576 return 0;
577 }
578
579 if (s->in_flight >= MAX_IN_FLIGHT) {
580 trace_mirror_yield(s, s->in_flight, s->buf_free_count, -1);
581 mirror_wait_for_io(s);
582 continue;
583 }
584
585 mirror_do_zero_or_discard(s, sector_num, nb_sectors, false);
586 sector_num += nb_sectors;
587 }
588
589 mirror_wait_for_all_io(s);
590 }
591
592 /* First part, loop on the sectors and initialize the dirty bitmap. */
593 for (sector_num = 0; sector_num < end; ) {
594 /* Just to make sure we are not exceeding int limit. */
595 int nb_sectors = MIN(INT_MAX >> BDRV_SECTOR_BITS,
596 end - sector_num);
597
598 mirror_throttle(s);
599
600 if (block_job_is_cancelled(&s->common)) {
601 return 0;
602 }
603
604 ret = bdrv_is_allocated_above(bs, base, sector_num, nb_sectors, &n);
605 if (ret < 0) {
606 return ret;
607 }
608
609 assert(n > 0);
610 if (ret == 1) {
611 bdrv_set_dirty_bitmap(s->dirty_bitmap, sector_num, n);
612 }
613 sector_num += n;
614 }
615 return 0;
616 }
617
618 /* Called when going out of the streaming phase to flush the bulk of the
619 * data to the medium, or just before completing.
620 */
621 static int mirror_flush(MirrorBlockJob *s)
622 {
623 int ret = blk_flush(s->target);
624 if (ret < 0) {
625 if (mirror_error_action(s, false, -ret) == BLOCK_ERROR_ACTION_REPORT) {
626 s->ret = ret;
627 }
628 }
629 return ret;
630 }
631
632 static void coroutine_fn mirror_run(void *opaque)
633 {
634 MirrorBlockJob *s = opaque;
635 MirrorExitData *data;
636 BlockDriverState *bs = blk_bs(s->common.blk);
637 BlockDriverState *target_bs = blk_bs(s->target);
638 bool need_drain = true;
639 int64_t length;
640 BlockDriverInfo bdi;
641 char backing_filename[2]; /* we only need 2 characters because we are only
642 checking for a NULL string */
643 int ret = 0;
644 int target_cluster_size = BDRV_SECTOR_SIZE;
645
646 if (block_job_is_cancelled(&s->common)) {
647 goto immediate_exit;
648 }
649
650 s->bdev_length = bdrv_getlength(bs);
651 if (s->bdev_length < 0) {
652 ret = s->bdev_length;
653 goto immediate_exit;
654 } else if (s->bdev_length == 0) {
655 /* Report BLOCK_JOB_READY and wait for complete. */
656 block_job_event_ready(&s->common);
657 s->synced = true;
658 while (!block_job_is_cancelled(&s->common) && !s->should_complete) {
659 block_job_yield(&s->common);
660 }
661 s->common.cancelled = false;
662 goto immediate_exit;
663 }
664
665 length = DIV_ROUND_UP(s->bdev_length, s->granularity);
666 s->in_flight_bitmap = bitmap_new(length);
667
668 /* If we have no backing file yet in the destination, we cannot let
669 * the destination do COW. Instead, we copy sectors around the
670 * dirty data if needed. We need a bitmap to do that.
671 */
672 bdrv_get_backing_filename(target_bs, backing_filename,
673 sizeof(backing_filename));
674 if (!bdrv_get_info(target_bs, &bdi) && bdi.cluster_size) {
675 target_cluster_size = bdi.cluster_size;
676 }
677 if (backing_filename[0] && !target_bs->backing
678 && s->granularity < target_cluster_size) {
679 s->buf_size = MAX(s->buf_size, target_cluster_size);
680 s->cow_bitmap = bitmap_new(length);
681 }
682 s->target_cluster_sectors = target_cluster_size >> BDRV_SECTOR_BITS;
683 s->max_iov = MIN(bs->bl.max_iov, target_bs->bl.max_iov);
684
685 s->buf = qemu_try_blockalign(bs, s->buf_size);
686 if (s->buf == NULL) {
687 ret = -ENOMEM;
688 goto immediate_exit;
689 }
690
691 mirror_free_init(s);
692
693 s->last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
694 if (!s->is_none_mode) {
695 ret = mirror_dirty_init(s);
696 if (ret < 0 || block_job_is_cancelled(&s->common)) {
697 goto immediate_exit;
698 }
699 }
700
701 assert(!s->dbi);
702 s->dbi = bdrv_dirty_iter_new(s->dirty_bitmap, 0);
703 for (;;) {
704 uint64_t delay_ns = 0;
705 int64_t cnt, delta;
706 bool should_complete;
707
708 if (s->ret < 0) {
709 ret = s->ret;
710 goto immediate_exit;
711 }
712
713 block_job_pause_point(&s->common);
714
715 cnt = bdrv_get_dirty_count(s->dirty_bitmap);
716 /* s->common.offset contains the number of bytes already processed so
717 * far, cnt is the number of dirty sectors remaining and
718 * s->sectors_in_flight is the number of sectors currently being
719 * processed; together those are the current total operation length */
720 s->common.len = s->common.offset +
721 (cnt + s->sectors_in_flight) * BDRV_SECTOR_SIZE;
722
723 /* Note that even when no rate limit is applied we need to yield
724 * periodically with no pending I/O so that bdrv_drain_all() returns.
725 * We do so every SLICE_TIME nanoseconds, or when there is an error,
726 * or when the source is clean, whichever comes first.
727 */
728 delta = qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - s->last_pause_ns;
729 if (delta < SLICE_TIME &&
730 s->common.iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
731 if (s->in_flight >= MAX_IN_FLIGHT || s->buf_free_count == 0 ||
732 (cnt == 0 && s->in_flight > 0)) {
733 trace_mirror_yield(s, s->in_flight, s->buf_free_count, cnt);
734 mirror_wait_for_io(s);
735 continue;
736 } else if (cnt != 0) {
737 delay_ns = mirror_iteration(s);
738 }
739 }
740
741 should_complete = false;
742 if (s->in_flight == 0 && cnt == 0) {
743 trace_mirror_before_flush(s);
744 if (!s->synced) {
745 if (mirror_flush(s) < 0) {
746 /* Go check s->ret. */
747 continue;
748 }
749 /* We're out of the streaming phase. From now on, if the job
750 * is cancelled we will actually complete all pending I/O and
751 * report completion. This way, block-job-cancel will leave
752 * the target in a consistent state.
753 */
754 block_job_event_ready(&s->common);
755 s->synced = true;
756 }
757
758 should_complete = s->should_complete ||
759 block_job_is_cancelled(&s->common);
760 cnt = bdrv_get_dirty_count(s->dirty_bitmap);
761 }
762
763 if (cnt == 0 && should_complete) {
764 /* The dirty bitmap is not updated while operations are pending.
765 * If we're about to exit, wait for pending operations before
766 * calling bdrv_get_dirty_count(bs), or we may exit while the
767 * source has dirty data to copy!
768 *
769 * Note that I/O can be submitted by the guest while
770 * mirror_populate runs, so pause it now. Before deciding
771 * whether to switch to target check one last time if I/O has
772 * come in the meanwhile, and if not flush the data to disk.
773 */
774 trace_mirror_before_drain(s, cnt);
775
776 bdrv_drained_begin(bs);
777 cnt = bdrv_get_dirty_count(s->dirty_bitmap);
778 if (cnt > 0 || mirror_flush(s) < 0) {
779 bdrv_drained_end(bs);
780 continue;
781 }
782
783 /* The two disks are in sync. Exit and report successful
784 * completion.
785 */
786 assert(QLIST_EMPTY(&bs->tracked_requests));
787 s->common.cancelled = false;
788 need_drain = false;
789 break;
790 }
791
792 ret = 0;
793 trace_mirror_before_sleep(s, cnt, s->synced, delay_ns);
794 if (!s->synced) {
795 block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns);
796 if (block_job_is_cancelled(&s->common)) {
797 break;
798 }
799 } else if (!should_complete) {
800 delay_ns = (s->in_flight == 0 && cnt == 0 ? SLICE_TIME : 0);
801 block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns);
802 }
803 s->last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
804 }
805
806 immediate_exit:
807 if (s->in_flight > 0) {
808 /* We get here only if something went wrong. Either the job failed,
809 * or it was cancelled prematurely so that we do not guarantee that
810 * the target is a copy of the source.
811 */
812 assert(ret < 0 || (!s->synced && block_job_is_cancelled(&s->common)));
813 assert(need_drain);
814 mirror_wait_for_all_io(s);
815 }
816
817 assert(s->in_flight == 0);
818 qemu_vfree(s->buf);
819 g_free(s->cow_bitmap);
820 g_free(s->in_flight_bitmap);
821 bdrv_dirty_iter_free(s->dbi);
822 bdrv_release_dirty_bitmap(bs, s->dirty_bitmap);
823
824 data = g_malloc(sizeof(*data));
825 data->ret = ret;
826
827 if (need_drain) {
828 bdrv_drained_begin(bs);
829 }
830 block_job_defer_to_main_loop(&s->common, mirror_exit, data);
831 }
832
833 static void mirror_set_speed(BlockJob *job, int64_t speed, Error **errp)
834 {
835 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common);
836
837 if (speed < 0) {
838 error_setg(errp, QERR_INVALID_PARAMETER, "speed");
839 return;
840 }
841 ratelimit_set_speed(&s->limit, speed / BDRV_SECTOR_SIZE, SLICE_TIME);
842 }
843
844 static void mirror_complete(BlockJob *job, Error **errp)
845 {
846 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common);
847 BlockDriverState *src, *target;
848
849 src = blk_bs(job->blk);
850 target = blk_bs(s->target);
851
852 if (!s->synced) {
853 error_setg(errp, "The active block job '%s' cannot be completed",
854 job->id);
855 return;
856 }
857
858 if (s->backing_mode == MIRROR_OPEN_BACKING_CHAIN) {
859 int ret;
860
861 assert(!target->backing);
862 ret = bdrv_open_backing_file(target, NULL, "backing", errp);
863 if (ret < 0) {
864 return;
865 }
866 }
867
868 /* block all operations on to_replace bs */
869 if (s->replaces) {
870 AioContext *replace_aio_context;
871
872 s->to_replace = bdrv_find_node(s->replaces);
873 if (!s->to_replace) {
874 error_setg(errp, "Node name '%s' not found", s->replaces);
875 return;
876 }
877
878 replace_aio_context = bdrv_get_aio_context(s->to_replace);
879 aio_context_acquire(replace_aio_context);
880
881 error_setg(&s->replace_blocker,
882 "block device is in use by block-job-complete");
883 bdrv_op_block_all(s->to_replace, s->replace_blocker);
884 bdrv_ref(s->to_replace);
885
886 aio_context_release(replace_aio_context);
887 }
888
889 if (s->backing_mode == MIRROR_SOURCE_BACKING_CHAIN) {
890 BlockDriverState *backing = s->is_none_mode ? src : s->base;
891 if (backing_bs(target) != backing) {
892 bdrv_set_backing_hd(target, backing);
893 }
894 }
895
896 s->should_complete = true;
897 block_job_enter(&s->common);
898 }
899
900 static void mirror_pause(BlockJob *job)
901 {
902 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common);
903
904 mirror_wait_for_all_io(s);
905 }
906
907 static void mirror_attached_aio_context(BlockJob *job, AioContext *new_context)
908 {
909 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common);
910
911 blk_set_aio_context(s->target, new_context);
912 }
913
914 static void mirror_drain(BlockJob *job)
915 {
916 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common);
917
918 /* Need to keep a reference in case blk_drain triggers execution
919 * of mirror_complete...
920 */
921 if (s->target) {
922 BlockBackend *target = s->target;
923 blk_ref(target);
924 blk_drain(target);
925 blk_unref(target);
926 }
927 }
928
929 static const BlockJobDriver mirror_job_driver = {
930 .instance_size = sizeof(MirrorBlockJob),
931 .job_type = BLOCK_JOB_TYPE_MIRROR,
932 .set_speed = mirror_set_speed,
933 .start = mirror_run,
934 .complete = mirror_complete,
935 .pause = mirror_pause,
936 .attached_aio_context = mirror_attached_aio_context,
937 .drain = mirror_drain,
938 };
939
940 static const BlockJobDriver commit_active_job_driver = {
941 .instance_size = sizeof(MirrorBlockJob),
942 .job_type = BLOCK_JOB_TYPE_COMMIT,
943 .set_speed = mirror_set_speed,
944 .start = mirror_run,
945 .complete = mirror_complete,
946 .pause = mirror_pause,
947 .attached_aio_context = mirror_attached_aio_context,
948 .drain = mirror_drain,
949 };
950
951 static void mirror_start_job(const char *job_id, BlockDriverState *bs,
952 int creation_flags, BlockDriverState *target,
953 const char *replaces, int64_t speed,
954 uint32_t granularity, int64_t buf_size,
955 BlockMirrorBackingMode backing_mode,
956 BlockdevOnError on_source_error,
957 BlockdevOnError on_target_error,
958 bool unmap,
959 BlockCompletionFunc *cb,
960 void *opaque, Error **errp,
961 const BlockJobDriver *driver,
962 bool is_none_mode, BlockDriverState *base,
963 bool auto_complete)
964 {
965 MirrorBlockJob *s;
966
967 if (granularity == 0) {
968 granularity = bdrv_get_default_bitmap_granularity(target);
969 }
970
971 assert ((granularity & (granularity - 1)) == 0);
972
973 if (buf_size < 0) {
974 error_setg(errp, "Invalid parameter 'buf-size'");
975 return;
976 }
977
978 if (buf_size == 0) {
979 buf_size = DEFAULT_MIRROR_BUF_SIZE;
980 }
981
982 s = block_job_create(job_id, driver, bs, speed, creation_flags,
983 cb, opaque, errp);
984 if (!s) {
985 return;
986 }
987
988 s->target = blk_new();
989 blk_insert_bs(s->target, target);
990
991 s->replaces = g_strdup(replaces);
992 s->on_source_error = on_source_error;
993 s->on_target_error = on_target_error;
994 s->is_none_mode = is_none_mode;
995 s->backing_mode = backing_mode;
996 s->base = base;
997 s->granularity = granularity;
998 s->buf_size = ROUND_UP(buf_size, granularity);
999 s->unmap = unmap;
1000 if (auto_complete) {
1001 s->should_complete = true;
1002 }
1003
1004 s->dirty_bitmap = bdrv_create_dirty_bitmap(bs, granularity, NULL, errp);
1005 if (!s->dirty_bitmap) {
1006 g_free(s->replaces);
1007 blk_unref(s->target);
1008 block_job_unref(&s->common);
1009 return;
1010 }
1011
1012 block_job_add_bdrv(&s->common, target);
1013 /* In commit_active_start() all intermediate nodes disappear, so
1014 * any jobs in them must be blocked */
1015 if (bdrv_chain_contains(bs, target)) {
1016 BlockDriverState *iter;
1017 for (iter = backing_bs(bs); iter != target; iter = backing_bs(iter)) {
1018 block_job_add_bdrv(&s->common, iter);
1019 }
1020 }
1021
1022 trace_mirror_start(bs, s, opaque);
1023 block_job_start(&s->common);
1024 }
1025
1026 void mirror_start(const char *job_id, BlockDriverState *bs,
1027 BlockDriverState *target, const char *replaces,
1028 int64_t speed, uint32_t granularity, int64_t buf_size,
1029 MirrorSyncMode mode, BlockMirrorBackingMode backing_mode,
1030 BlockdevOnError on_source_error,
1031 BlockdevOnError on_target_error,
1032 bool unmap, Error **errp)
1033 {
1034 bool is_none_mode;
1035 BlockDriverState *base;
1036
1037 if (mode == MIRROR_SYNC_MODE_INCREMENTAL) {
1038 error_setg(errp, "Sync mode 'incremental' not supported");
1039 return;
1040 }
1041 is_none_mode = mode == MIRROR_SYNC_MODE_NONE;
1042 base = mode == MIRROR_SYNC_MODE_TOP ? backing_bs(bs) : NULL;
1043 mirror_start_job(job_id, bs, BLOCK_JOB_DEFAULT, target, replaces,
1044 speed, granularity, buf_size, backing_mode,
1045 on_source_error, on_target_error, unmap, NULL, NULL, errp,
1046 &mirror_job_driver, is_none_mode, base, false);
1047 }
1048
1049 void commit_active_start(const char *job_id, BlockDriverState *bs,
1050 BlockDriverState *base, int creation_flags,
1051 int64_t speed, BlockdevOnError on_error,
1052 BlockCompletionFunc *cb, void *opaque, Error **errp,
1053 bool auto_complete)
1054 {
1055 int64_t length, base_length;
1056 int orig_base_flags;
1057 int ret;
1058 Error *local_err = NULL;
1059
1060 orig_base_flags = bdrv_get_flags(base);
1061
1062 if (bdrv_reopen(base, bs->open_flags, errp)) {
1063 return;
1064 }
1065
1066 length = bdrv_getlength(bs);
1067 if (length < 0) {
1068 error_setg_errno(errp, -length,
1069 "Unable to determine length of %s", bs->filename);
1070 goto error_restore_flags;
1071 }
1072
1073 base_length = bdrv_getlength(base);
1074 if (base_length < 0) {
1075 error_setg_errno(errp, -base_length,
1076 "Unable to determine length of %s", base->filename);
1077 goto error_restore_flags;
1078 }
1079
1080 if (length > base_length) {
1081 ret = bdrv_truncate(base, length);
1082 if (ret < 0) {
1083 error_setg_errno(errp, -ret,
1084 "Top image %s is larger than base image %s, and "
1085 "resize of base image failed",
1086 bs->filename, base->filename);
1087 goto error_restore_flags;
1088 }
1089 }
1090
1091 mirror_start_job(job_id, bs, creation_flags, base, NULL, speed, 0, 0,
1092 MIRROR_LEAVE_BACKING_CHAIN,
1093 on_error, on_error, true, cb, opaque, &local_err,
1094 &commit_active_job_driver, false, base, auto_complete);
1095 if (local_err) {
1096 error_propagate(errp, local_err);
1097 goto error_restore_flags;
1098 }
1099
1100 return;
1101
1102 error_restore_flags:
1103 /* ignore error and errp for bdrv_reopen, because we want to propagate
1104 * the original error */
1105 bdrv_reopen(base, orig_base_flags, NULL);
1106 return;
1107 }