Merge remote-tracking branch 'remotes/mst/tags/for_upstream' into staging
[qemu.git] / migration / block.c
1 /*
2 * QEMU live block migration
3 *
4 * Copyright IBM, Corp. 2009
5 *
6 * Authors:
7 * Liran Schour <lirans@il.ibm.com>
8 *
9 * This work is licensed under the terms of the GNU GPL, version 2. See
10 * the COPYING file in the top-level directory.
11 *
12 * Contributions after 2012-01-13 are licensed under the terms of the
13 * GNU GPL, version 2 or (at your option) any later version.
14 */
15
16 #include "qemu/osdep.h"
17 #include "qapi/error.h"
18 #include "qemu/error-report.h"
19 #include "qemu/main-loop.h"
20 #include "qemu/cutils.h"
21 #include "qemu/queue.h"
22 #include "block.h"
23 #include "migration/misc.h"
24 #include "migration.h"
25 #include "migration/register.h"
26 #include "qemu-file.h"
27 #include "migration/vmstate.h"
28 #include "sysemu/block-backend.h"
29
30 #define BLOCK_SIZE (1 << 20)
31 #define BDRV_SECTORS_PER_DIRTY_CHUNK (BLOCK_SIZE >> BDRV_SECTOR_BITS)
32
33 #define BLK_MIG_FLAG_DEVICE_BLOCK 0x01
34 #define BLK_MIG_FLAG_EOS 0x02
35 #define BLK_MIG_FLAG_PROGRESS 0x04
36 #define BLK_MIG_FLAG_ZERO_BLOCK 0x08
37
38 #define MAX_IS_ALLOCATED_SEARCH (65536 * BDRV_SECTOR_SIZE)
39
40 #define MAX_IO_BUFFERS 512
41 #define MAX_PARALLEL_IO 16
42
43 //#define DEBUG_BLK_MIGRATION
44
45 #ifdef DEBUG_BLK_MIGRATION
46 #define DPRINTF(fmt, ...) \
47 do { printf("blk_migration: " fmt, ## __VA_ARGS__); } while (0)
48 #else
49 #define DPRINTF(fmt, ...) \
50 do { } while (0)
51 #endif
52
53 typedef struct BlkMigDevState {
54 /* Written during setup phase. Can be read without a lock. */
55 BlockBackend *blk;
56 char *blk_name;
57 int shared_base;
58 int64_t total_sectors;
59 QSIMPLEQ_ENTRY(BlkMigDevState) entry;
60 Error *blocker;
61
62 /* Only used by migration thread. Does not need a lock. */
63 int bulk_completed;
64 int64_t cur_sector;
65 int64_t cur_dirty;
66
67 /* Data in the aio_bitmap is protected by block migration lock.
68 * Allocation and free happen during setup and cleanup respectively.
69 */
70 unsigned long *aio_bitmap;
71
72 /* Protected by block migration lock. */
73 int64_t completed_sectors;
74
75 /* During migration this is protected by iothread lock / AioContext.
76 * Allocation and free happen during setup and cleanup respectively.
77 */
78 BdrvDirtyBitmap *dirty_bitmap;
79 } BlkMigDevState;
80
81 typedef struct BlkMigBlock {
82 /* Only used by migration thread. */
83 uint8_t *buf;
84 BlkMigDevState *bmds;
85 int64_t sector;
86 int nr_sectors;
87 QEMUIOVector qiov;
88 BlockAIOCB *aiocb;
89
90 /* Protected by block migration lock. */
91 int ret;
92 QSIMPLEQ_ENTRY(BlkMigBlock) entry;
93 } BlkMigBlock;
94
95 typedef struct BlkMigState {
96 QSIMPLEQ_HEAD(, BlkMigDevState) bmds_list;
97 int64_t total_sector_sum;
98 bool zero_blocks;
99
100 /* Protected by lock. */
101 QSIMPLEQ_HEAD(, BlkMigBlock) blk_list;
102 int submitted;
103 int read_done;
104
105 /* Only used by migration thread. Does not need a lock. */
106 int transferred;
107 int prev_progress;
108 int bulk_completed;
109
110 /* Lock must be taken _inside_ the iothread lock and any AioContexts. */
111 QemuMutex lock;
112 } BlkMigState;
113
114 static BlkMigState block_mig_state;
115
116 static void blk_mig_lock(void)
117 {
118 qemu_mutex_lock(&block_mig_state.lock);
119 }
120
121 static void blk_mig_unlock(void)
122 {
123 qemu_mutex_unlock(&block_mig_state.lock);
124 }
125
126 /* Must run outside of the iothread lock during the bulk phase,
127 * or the VM will stall.
128 */
129
130 static void blk_send(QEMUFile *f, BlkMigBlock * blk)
131 {
132 int len;
133 uint64_t flags = BLK_MIG_FLAG_DEVICE_BLOCK;
134
135 if (block_mig_state.zero_blocks &&
136 buffer_is_zero(blk->buf, BLOCK_SIZE)) {
137 flags |= BLK_MIG_FLAG_ZERO_BLOCK;
138 }
139
140 /* sector number and flags */
141 qemu_put_be64(f, (blk->sector << BDRV_SECTOR_BITS)
142 | flags);
143
144 /* device name */
145 len = strlen(blk->bmds->blk_name);
146 qemu_put_byte(f, len);
147 qemu_put_buffer(f, (uint8_t *) blk->bmds->blk_name, len);
148
149 /* if a block is zero we need to flush here since the network
150 * bandwidth is now a lot higher than the storage device bandwidth.
151 * thus if we queue zero blocks we slow down the migration */
152 if (flags & BLK_MIG_FLAG_ZERO_BLOCK) {
153 qemu_fflush(f);
154 return;
155 }
156
157 qemu_put_buffer(f, blk->buf, BLOCK_SIZE);
158 }
159
160 int blk_mig_active(void)
161 {
162 return !QSIMPLEQ_EMPTY(&block_mig_state.bmds_list);
163 }
164
165 int blk_mig_bulk_active(void)
166 {
167 return blk_mig_active() && !block_mig_state.bulk_completed;
168 }
169
170 uint64_t blk_mig_bytes_transferred(void)
171 {
172 BlkMigDevState *bmds;
173 uint64_t sum = 0;
174
175 blk_mig_lock();
176 QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
177 sum += bmds->completed_sectors;
178 }
179 blk_mig_unlock();
180 return sum << BDRV_SECTOR_BITS;
181 }
182
183 uint64_t blk_mig_bytes_remaining(void)
184 {
185 return blk_mig_bytes_total() - blk_mig_bytes_transferred();
186 }
187
188 uint64_t blk_mig_bytes_total(void)
189 {
190 BlkMigDevState *bmds;
191 uint64_t sum = 0;
192
193 QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
194 sum += bmds->total_sectors;
195 }
196 return sum << BDRV_SECTOR_BITS;
197 }
198
199
200 /* Called with migration lock held. */
201
202 static int bmds_aio_inflight(BlkMigDevState *bmds, int64_t sector)
203 {
204 int64_t chunk = sector / (int64_t)BDRV_SECTORS_PER_DIRTY_CHUNK;
205
206 if (sector < blk_nb_sectors(bmds->blk)) {
207 return !!(bmds->aio_bitmap[chunk / (sizeof(unsigned long) * 8)] &
208 (1UL << (chunk % (sizeof(unsigned long) * 8))));
209 } else {
210 return 0;
211 }
212 }
213
214 /* Called with migration lock held. */
215
216 static void bmds_set_aio_inflight(BlkMigDevState *bmds, int64_t sector_num,
217 int nb_sectors, int set)
218 {
219 int64_t start, end;
220 unsigned long val, idx, bit;
221
222 start = sector_num / BDRV_SECTORS_PER_DIRTY_CHUNK;
223 end = (sector_num + nb_sectors - 1) / BDRV_SECTORS_PER_DIRTY_CHUNK;
224
225 for (; start <= end; start++) {
226 idx = start / (sizeof(unsigned long) * 8);
227 bit = start % (sizeof(unsigned long) * 8);
228 val = bmds->aio_bitmap[idx];
229 if (set) {
230 val |= 1UL << bit;
231 } else {
232 val &= ~(1UL << bit);
233 }
234 bmds->aio_bitmap[idx] = val;
235 }
236 }
237
238 static void alloc_aio_bitmap(BlkMigDevState *bmds)
239 {
240 BlockBackend *bb = bmds->blk;
241 int64_t bitmap_size;
242
243 bitmap_size = blk_nb_sectors(bb) + BDRV_SECTORS_PER_DIRTY_CHUNK * 8 - 1;
244 bitmap_size /= BDRV_SECTORS_PER_DIRTY_CHUNK * 8;
245
246 bmds->aio_bitmap = g_malloc0(bitmap_size);
247 }
248
249 /* Never hold migration lock when yielding to the main loop! */
250
251 static void blk_mig_read_cb(void *opaque, int ret)
252 {
253 BlkMigBlock *blk = opaque;
254
255 blk_mig_lock();
256 blk->ret = ret;
257
258 QSIMPLEQ_INSERT_TAIL(&block_mig_state.blk_list, blk, entry);
259 bmds_set_aio_inflight(blk->bmds, blk->sector, blk->nr_sectors, 0);
260
261 block_mig_state.submitted--;
262 block_mig_state.read_done++;
263 assert(block_mig_state.submitted >= 0);
264 blk_mig_unlock();
265 }
266
267 /* Called with no lock taken. */
268
269 static int mig_save_device_bulk(QEMUFile *f, BlkMigDevState *bmds)
270 {
271 int64_t total_sectors = bmds->total_sectors;
272 int64_t cur_sector = bmds->cur_sector;
273 BlockBackend *bb = bmds->blk;
274 BlkMigBlock *blk;
275 int nr_sectors;
276 int64_t count;
277
278 if (bmds->shared_base) {
279 qemu_mutex_lock_iothread();
280 aio_context_acquire(blk_get_aio_context(bb));
281 /* Skip unallocated sectors; intentionally treats failure or
282 * partial sector as an allocated sector */
283 while (cur_sector < total_sectors &&
284 !bdrv_is_allocated(blk_bs(bb), cur_sector * BDRV_SECTOR_SIZE,
285 MAX_IS_ALLOCATED_SEARCH, &count)) {
286 if (count < BDRV_SECTOR_SIZE) {
287 break;
288 }
289 cur_sector += count >> BDRV_SECTOR_BITS;
290 }
291 aio_context_release(blk_get_aio_context(bb));
292 qemu_mutex_unlock_iothread();
293 }
294
295 if (cur_sector >= total_sectors) {
296 bmds->cur_sector = bmds->completed_sectors = total_sectors;
297 return 1;
298 }
299
300 bmds->completed_sectors = cur_sector;
301
302 cur_sector &= ~((int64_t)BDRV_SECTORS_PER_DIRTY_CHUNK - 1);
303
304 /* we are going to transfer a full block even if it is not allocated */
305 nr_sectors = BDRV_SECTORS_PER_DIRTY_CHUNK;
306
307 if (total_sectors - cur_sector < BDRV_SECTORS_PER_DIRTY_CHUNK) {
308 nr_sectors = total_sectors - cur_sector;
309 }
310
311 blk = g_new(BlkMigBlock, 1);
312 blk->buf = g_malloc(BLOCK_SIZE);
313 blk->bmds = bmds;
314 blk->sector = cur_sector;
315 blk->nr_sectors = nr_sectors;
316
317 qemu_iovec_init_buf(&blk->qiov, blk->buf, nr_sectors * BDRV_SECTOR_SIZE);
318
319 blk_mig_lock();
320 block_mig_state.submitted++;
321 blk_mig_unlock();
322
323 /* We do not know if bs is under the main thread (and thus does
324 * not acquire the AioContext when doing AIO) or rather under
325 * dataplane. Thus acquire both the iothread mutex and the
326 * AioContext.
327 *
328 * This is ugly and will disappear when we make bdrv_* thread-safe,
329 * without the need to acquire the AioContext.
330 */
331 qemu_mutex_lock_iothread();
332 aio_context_acquire(blk_get_aio_context(bmds->blk));
333 bdrv_reset_dirty_bitmap(bmds->dirty_bitmap, cur_sector * BDRV_SECTOR_SIZE,
334 nr_sectors * BDRV_SECTOR_SIZE);
335 blk->aiocb = blk_aio_preadv(bb, cur_sector * BDRV_SECTOR_SIZE, &blk->qiov,
336 0, blk_mig_read_cb, blk);
337 aio_context_release(blk_get_aio_context(bmds->blk));
338 qemu_mutex_unlock_iothread();
339
340 bmds->cur_sector = cur_sector + nr_sectors;
341 return (bmds->cur_sector >= total_sectors);
342 }
343
344 /* Called with iothread lock taken. */
345
346 static int set_dirty_tracking(void)
347 {
348 BlkMigDevState *bmds;
349 int ret;
350
351 QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
352 bmds->dirty_bitmap = bdrv_create_dirty_bitmap(blk_bs(bmds->blk),
353 BLOCK_SIZE, NULL, NULL);
354 if (!bmds->dirty_bitmap) {
355 ret = -errno;
356 goto fail;
357 }
358 }
359 return 0;
360
361 fail:
362 QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
363 if (bmds->dirty_bitmap) {
364 bdrv_release_dirty_bitmap(bmds->dirty_bitmap);
365 }
366 }
367 return ret;
368 }
369
370 /* Called with iothread lock taken. */
371
372 static void unset_dirty_tracking(void)
373 {
374 BlkMigDevState *bmds;
375
376 QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
377 bdrv_release_dirty_bitmap(bmds->dirty_bitmap);
378 }
379 }
380
381 static int init_blk_migration(QEMUFile *f)
382 {
383 BlockDriverState *bs;
384 BlkMigDevState *bmds;
385 int64_t sectors;
386 BdrvNextIterator it;
387 int i, num_bs = 0;
388 struct {
389 BlkMigDevState *bmds;
390 BlockDriverState *bs;
391 } *bmds_bs;
392 Error *local_err = NULL;
393 int ret;
394
395 block_mig_state.submitted = 0;
396 block_mig_state.read_done = 0;
397 block_mig_state.transferred = 0;
398 block_mig_state.total_sector_sum = 0;
399 block_mig_state.prev_progress = -1;
400 block_mig_state.bulk_completed = 0;
401 block_mig_state.zero_blocks = migrate_zero_blocks();
402
403 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
404 num_bs++;
405 }
406 bmds_bs = g_malloc0(num_bs * sizeof(*bmds_bs));
407
408 for (i = 0, bs = bdrv_first(&it); bs; bs = bdrv_next(&it), i++) {
409 if (bdrv_is_read_only(bs)) {
410 continue;
411 }
412
413 sectors = bdrv_nb_sectors(bs);
414 if (sectors <= 0) {
415 ret = sectors;
416 bdrv_next_cleanup(&it);
417 goto out;
418 }
419
420 bmds = g_new0(BlkMigDevState, 1);
421 bmds->blk = blk_new(qemu_get_aio_context(),
422 BLK_PERM_CONSISTENT_READ, BLK_PERM_ALL);
423 bmds->blk_name = g_strdup(bdrv_get_device_name(bs));
424 bmds->bulk_completed = 0;
425 bmds->total_sectors = sectors;
426 bmds->completed_sectors = 0;
427 bmds->shared_base = migrate_use_block_incremental();
428
429 assert(i < num_bs);
430 bmds_bs[i].bmds = bmds;
431 bmds_bs[i].bs = bs;
432
433 block_mig_state.total_sector_sum += sectors;
434
435 if (bmds->shared_base) {
436 DPRINTF("Start migration for %s with shared base image\n",
437 bdrv_get_device_name(bs));
438 } else {
439 DPRINTF("Start full migration for %s\n", bdrv_get_device_name(bs));
440 }
441
442 QSIMPLEQ_INSERT_TAIL(&block_mig_state.bmds_list, bmds, entry);
443 }
444
445 /* Can only insert new BDSes now because doing so while iterating block
446 * devices may end up in a deadlock (iterating the new BDSes, too). */
447 for (i = 0; i < num_bs; i++) {
448 BlkMigDevState *bmds = bmds_bs[i].bmds;
449 BlockDriverState *bs = bmds_bs[i].bs;
450
451 if (bmds) {
452 ret = blk_insert_bs(bmds->blk, bs, &local_err);
453 if (ret < 0) {
454 error_report_err(local_err);
455 goto out;
456 }
457
458 alloc_aio_bitmap(bmds);
459 error_setg(&bmds->blocker, "block device is in use by migration");
460 bdrv_op_block_all(bs, bmds->blocker);
461 }
462 }
463
464 ret = 0;
465 out:
466 g_free(bmds_bs);
467 return ret;
468 }
469
470 /* Called with no lock taken. */
471
472 static int blk_mig_save_bulked_block(QEMUFile *f)
473 {
474 int64_t completed_sector_sum = 0;
475 BlkMigDevState *bmds;
476 int progress;
477 int ret = 0;
478
479 QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
480 if (bmds->bulk_completed == 0) {
481 if (mig_save_device_bulk(f, bmds) == 1) {
482 /* completed bulk section for this device */
483 bmds->bulk_completed = 1;
484 }
485 completed_sector_sum += bmds->completed_sectors;
486 ret = 1;
487 break;
488 } else {
489 completed_sector_sum += bmds->completed_sectors;
490 }
491 }
492
493 if (block_mig_state.total_sector_sum != 0) {
494 progress = completed_sector_sum * 100 /
495 block_mig_state.total_sector_sum;
496 } else {
497 progress = 100;
498 }
499 if (progress != block_mig_state.prev_progress) {
500 block_mig_state.prev_progress = progress;
501 qemu_put_be64(f, (progress << BDRV_SECTOR_BITS)
502 | BLK_MIG_FLAG_PROGRESS);
503 DPRINTF("Completed %d %%\r", progress);
504 }
505
506 return ret;
507 }
508
509 static void blk_mig_reset_dirty_cursor(void)
510 {
511 BlkMigDevState *bmds;
512
513 QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
514 bmds->cur_dirty = 0;
515 }
516 }
517
518 /* Called with iothread lock and AioContext taken. */
519
520 static int mig_save_device_dirty(QEMUFile *f, BlkMigDevState *bmds,
521 int is_async)
522 {
523 BlkMigBlock *blk;
524 int64_t total_sectors = bmds->total_sectors;
525 int64_t sector;
526 int nr_sectors;
527 int ret = -EIO;
528
529 for (sector = bmds->cur_dirty; sector < bmds->total_sectors;) {
530 blk_mig_lock();
531 if (bmds_aio_inflight(bmds, sector)) {
532 blk_mig_unlock();
533 blk_drain(bmds->blk);
534 } else {
535 blk_mig_unlock();
536 }
537 bdrv_dirty_bitmap_lock(bmds->dirty_bitmap);
538 if (bdrv_dirty_bitmap_get_locked(bmds->dirty_bitmap,
539 sector * BDRV_SECTOR_SIZE)) {
540 if (total_sectors - sector < BDRV_SECTORS_PER_DIRTY_CHUNK) {
541 nr_sectors = total_sectors - sector;
542 } else {
543 nr_sectors = BDRV_SECTORS_PER_DIRTY_CHUNK;
544 }
545 bdrv_reset_dirty_bitmap_locked(bmds->dirty_bitmap,
546 sector * BDRV_SECTOR_SIZE,
547 nr_sectors * BDRV_SECTOR_SIZE);
548 bdrv_dirty_bitmap_unlock(bmds->dirty_bitmap);
549
550 blk = g_new(BlkMigBlock, 1);
551 blk->buf = g_malloc(BLOCK_SIZE);
552 blk->bmds = bmds;
553 blk->sector = sector;
554 blk->nr_sectors = nr_sectors;
555
556 if (is_async) {
557 qemu_iovec_init_buf(&blk->qiov, blk->buf,
558 nr_sectors * BDRV_SECTOR_SIZE);
559
560 blk->aiocb = blk_aio_preadv(bmds->blk,
561 sector * BDRV_SECTOR_SIZE,
562 &blk->qiov, 0, blk_mig_read_cb,
563 blk);
564
565 blk_mig_lock();
566 block_mig_state.submitted++;
567 bmds_set_aio_inflight(bmds, sector, nr_sectors, 1);
568 blk_mig_unlock();
569 } else {
570 ret = blk_pread(bmds->blk, sector * BDRV_SECTOR_SIZE, blk->buf,
571 nr_sectors * BDRV_SECTOR_SIZE);
572 if (ret < 0) {
573 goto error;
574 }
575 blk_send(f, blk);
576
577 g_free(blk->buf);
578 g_free(blk);
579 }
580
581 sector += nr_sectors;
582 bmds->cur_dirty = sector;
583 break;
584 }
585
586 bdrv_dirty_bitmap_unlock(bmds->dirty_bitmap);
587 sector += BDRV_SECTORS_PER_DIRTY_CHUNK;
588 bmds->cur_dirty = sector;
589 }
590
591 return (bmds->cur_dirty >= bmds->total_sectors);
592
593 error:
594 DPRINTF("Error reading sector %" PRId64 "\n", sector);
595 g_free(blk->buf);
596 g_free(blk);
597 return ret;
598 }
599
600 /* Called with iothread lock taken.
601 *
602 * return value:
603 * 0: too much data for max_downtime
604 * 1: few enough data for max_downtime
605 */
606 static int blk_mig_save_dirty_block(QEMUFile *f, int is_async)
607 {
608 BlkMigDevState *bmds;
609 int ret = 1;
610
611 QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
612 aio_context_acquire(blk_get_aio_context(bmds->blk));
613 ret = mig_save_device_dirty(f, bmds, is_async);
614 aio_context_release(blk_get_aio_context(bmds->blk));
615 if (ret <= 0) {
616 break;
617 }
618 }
619
620 return ret;
621 }
622
623 /* Called with no locks taken. */
624
625 static int flush_blks(QEMUFile *f)
626 {
627 BlkMigBlock *blk;
628 int ret = 0;
629
630 DPRINTF("%s Enter submitted %d read_done %d transferred %d\n",
631 __func__, block_mig_state.submitted, block_mig_state.read_done,
632 block_mig_state.transferred);
633
634 blk_mig_lock();
635 while ((blk = QSIMPLEQ_FIRST(&block_mig_state.blk_list)) != NULL) {
636 if (qemu_file_rate_limit(f)) {
637 break;
638 }
639 if (blk->ret < 0) {
640 ret = blk->ret;
641 break;
642 }
643
644 QSIMPLEQ_REMOVE_HEAD(&block_mig_state.blk_list, entry);
645 blk_mig_unlock();
646 blk_send(f, blk);
647 blk_mig_lock();
648
649 g_free(blk->buf);
650 g_free(blk);
651
652 block_mig_state.read_done--;
653 block_mig_state.transferred++;
654 assert(block_mig_state.read_done >= 0);
655 }
656 blk_mig_unlock();
657
658 DPRINTF("%s Exit submitted %d read_done %d transferred %d\n", __func__,
659 block_mig_state.submitted, block_mig_state.read_done,
660 block_mig_state.transferred);
661 return ret;
662 }
663
664 /* Called with iothread lock taken. */
665
666 static int64_t get_remaining_dirty(void)
667 {
668 BlkMigDevState *bmds;
669 int64_t dirty = 0;
670
671 QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
672 aio_context_acquire(blk_get_aio_context(bmds->blk));
673 dirty += bdrv_get_dirty_count(bmds->dirty_bitmap);
674 aio_context_release(blk_get_aio_context(bmds->blk));
675 }
676
677 return dirty;
678 }
679
680
681
682 /* Called with iothread lock taken. */
683 static void block_migration_cleanup_bmds(void)
684 {
685 BlkMigDevState *bmds;
686 AioContext *ctx;
687
688 unset_dirty_tracking();
689
690 while ((bmds = QSIMPLEQ_FIRST(&block_mig_state.bmds_list)) != NULL) {
691 QSIMPLEQ_REMOVE_HEAD(&block_mig_state.bmds_list, entry);
692 bdrv_op_unblock_all(blk_bs(bmds->blk), bmds->blocker);
693 error_free(bmds->blocker);
694
695 /* Save ctx, because bmds->blk can disappear during blk_unref. */
696 ctx = blk_get_aio_context(bmds->blk);
697 aio_context_acquire(ctx);
698 blk_unref(bmds->blk);
699 aio_context_release(ctx);
700
701 g_free(bmds->blk_name);
702 g_free(bmds->aio_bitmap);
703 g_free(bmds);
704 }
705 }
706
707 /* Called with iothread lock taken. */
708 static void block_migration_cleanup(void *opaque)
709 {
710 BlkMigBlock *blk;
711
712 bdrv_drain_all();
713
714 block_migration_cleanup_bmds();
715
716 blk_mig_lock();
717 while ((blk = QSIMPLEQ_FIRST(&block_mig_state.blk_list)) != NULL) {
718 QSIMPLEQ_REMOVE_HEAD(&block_mig_state.blk_list, entry);
719 g_free(blk->buf);
720 g_free(blk);
721 }
722 blk_mig_unlock();
723 }
724
725 static int block_save_setup(QEMUFile *f, void *opaque)
726 {
727 int ret;
728
729 DPRINTF("Enter save live setup submitted %d transferred %d\n",
730 block_mig_state.submitted, block_mig_state.transferred);
731
732 qemu_mutex_lock_iothread();
733 ret = init_blk_migration(f);
734 if (ret < 0) {
735 qemu_mutex_unlock_iothread();
736 return ret;
737 }
738
739 /* start track dirty blocks */
740 ret = set_dirty_tracking();
741
742 qemu_mutex_unlock_iothread();
743
744 if (ret) {
745 return ret;
746 }
747
748 ret = flush_blks(f);
749 blk_mig_reset_dirty_cursor();
750 qemu_put_be64(f, BLK_MIG_FLAG_EOS);
751
752 return ret;
753 }
754
755 static int block_save_iterate(QEMUFile *f, void *opaque)
756 {
757 int ret;
758 int64_t last_ftell = qemu_ftell(f);
759 int64_t delta_ftell;
760
761 DPRINTF("Enter save live iterate submitted %d transferred %d\n",
762 block_mig_state.submitted, block_mig_state.transferred);
763
764 ret = flush_blks(f);
765 if (ret) {
766 return ret;
767 }
768
769 blk_mig_reset_dirty_cursor();
770
771 /* control the rate of transfer */
772 blk_mig_lock();
773 while (block_mig_state.read_done * BLOCK_SIZE <
774 qemu_file_get_rate_limit(f) &&
775 block_mig_state.submitted < MAX_PARALLEL_IO &&
776 (block_mig_state.submitted + block_mig_state.read_done) <
777 MAX_IO_BUFFERS) {
778 blk_mig_unlock();
779 if (block_mig_state.bulk_completed == 0) {
780 /* first finish the bulk phase */
781 if (blk_mig_save_bulked_block(f) == 0) {
782 /* finished saving bulk on all devices */
783 block_mig_state.bulk_completed = 1;
784 }
785 ret = 0;
786 } else {
787 /* Always called with iothread lock taken for
788 * simplicity, block_save_complete also calls it.
789 */
790 qemu_mutex_lock_iothread();
791 ret = blk_mig_save_dirty_block(f, 1);
792 qemu_mutex_unlock_iothread();
793 }
794 if (ret < 0) {
795 return ret;
796 }
797 blk_mig_lock();
798 if (ret != 0) {
799 /* no more dirty blocks */
800 break;
801 }
802 }
803 blk_mig_unlock();
804
805 ret = flush_blks(f);
806 if (ret) {
807 return ret;
808 }
809
810 qemu_put_be64(f, BLK_MIG_FLAG_EOS);
811 delta_ftell = qemu_ftell(f) - last_ftell;
812 if (delta_ftell > 0) {
813 return 1;
814 } else if (delta_ftell < 0) {
815 return -1;
816 } else {
817 return 0;
818 }
819 }
820
821 /* Called with iothread lock taken. */
822
823 static int block_save_complete(QEMUFile *f, void *opaque)
824 {
825 int ret;
826
827 DPRINTF("Enter save live complete submitted %d transferred %d\n",
828 block_mig_state.submitted, block_mig_state.transferred);
829
830 ret = flush_blks(f);
831 if (ret) {
832 return ret;
833 }
834
835 blk_mig_reset_dirty_cursor();
836
837 /* we know for sure that save bulk is completed and
838 all async read completed */
839 blk_mig_lock();
840 assert(block_mig_state.submitted == 0);
841 blk_mig_unlock();
842
843 do {
844 ret = blk_mig_save_dirty_block(f, 0);
845 if (ret < 0) {
846 return ret;
847 }
848 } while (ret == 0);
849
850 /* report completion */
851 qemu_put_be64(f, (100 << BDRV_SECTOR_BITS) | BLK_MIG_FLAG_PROGRESS);
852
853 DPRINTF("Block migration completed\n");
854
855 qemu_put_be64(f, BLK_MIG_FLAG_EOS);
856
857 /* Make sure that our BlockBackends are gone, so that the block driver
858 * nodes can be inactivated. */
859 block_migration_cleanup_bmds();
860
861 return 0;
862 }
863
864 static void block_save_pending(QEMUFile *f, void *opaque, uint64_t max_size,
865 uint64_t *res_precopy_only,
866 uint64_t *res_compatible,
867 uint64_t *res_postcopy_only)
868 {
869 /* Estimate pending number of bytes to send */
870 uint64_t pending;
871
872 qemu_mutex_lock_iothread();
873 pending = get_remaining_dirty();
874 qemu_mutex_unlock_iothread();
875
876 blk_mig_lock();
877 pending += block_mig_state.submitted * BLOCK_SIZE +
878 block_mig_state.read_done * BLOCK_SIZE;
879 blk_mig_unlock();
880
881 /* Report at least one block pending during bulk phase */
882 if (pending <= max_size && !block_mig_state.bulk_completed) {
883 pending = max_size + BLOCK_SIZE;
884 }
885
886 DPRINTF("Enter save live pending %" PRIu64 "\n", pending);
887 /* We don't do postcopy */
888 *res_precopy_only += pending;
889 }
890
891 static int block_load(QEMUFile *f, void *opaque, int version_id)
892 {
893 static int banner_printed;
894 int len, flags;
895 char device_name[256];
896 int64_t addr;
897 BlockBackend *blk, *blk_prev = NULL;
898 Error *local_err = NULL;
899 uint8_t *buf;
900 int64_t total_sectors = 0;
901 int nr_sectors;
902 int ret;
903 BlockDriverInfo bdi;
904 int cluster_size = BLOCK_SIZE;
905
906 do {
907 addr = qemu_get_be64(f);
908
909 flags = addr & (BDRV_SECTOR_SIZE - 1);
910 addr >>= BDRV_SECTOR_BITS;
911
912 if (flags & BLK_MIG_FLAG_DEVICE_BLOCK) {
913 /* get device name */
914 len = qemu_get_byte(f);
915 qemu_get_buffer(f, (uint8_t *)device_name, len);
916 device_name[len] = '\0';
917
918 blk = blk_by_name(device_name);
919 if (!blk) {
920 fprintf(stderr, "Error unknown block device %s\n",
921 device_name);
922 return -EINVAL;
923 }
924
925 if (blk != blk_prev) {
926 blk_prev = blk;
927 total_sectors = blk_nb_sectors(blk);
928 if (total_sectors <= 0) {
929 error_report("Error getting length of block device %s",
930 device_name);
931 return -EINVAL;
932 }
933
934 blk_invalidate_cache(blk, &local_err);
935 if (local_err) {
936 error_report_err(local_err);
937 return -EINVAL;
938 }
939
940 ret = bdrv_get_info(blk_bs(blk), &bdi);
941 if (ret == 0 && bdi.cluster_size > 0 &&
942 bdi.cluster_size <= BLOCK_SIZE &&
943 BLOCK_SIZE % bdi.cluster_size == 0) {
944 cluster_size = bdi.cluster_size;
945 } else {
946 cluster_size = BLOCK_SIZE;
947 }
948 }
949
950 if (total_sectors - addr < BDRV_SECTORS_PER_DIRTY_CHUNK) {
951 nr_sectors = total_sectors - addr;
952 } else {
953 nr_sectors = BDRV_SECTORS_PER_DIRTY_CHUNK;
954 }
955
956 if (flags & BLK_MIG_FLAG_ZERO_BLOCK) {
957 ret = blk_pwrite_zeroes(blk, addr * BDRV_SECTOR_SIZE,
958 nr_sectors * BDRV_SECTOR_SIZE,
959 BDRV_REQ_MAY_UNMAP);
960 } else {
961 int i;
962 int64_t cur_addr;
963 uint8_t *cur_buf;
964
965 buf = g_malloc(BLOCK_SIZE);
966 qemu_get_buffer(f, buf, BLOCK_SIZE);
967 for (i = 0; i < BLOCK_SIZE / cluster_size; i++) {
968 cur_addr = addr * BDRV_SECTOR_SIZE + i * cluster_size;
969 cur_buf = buf + i * cluster_size;
970
971 if ((!block_mig_state.zero_blocks ||
972 cluster_size < BLOCK_SIZE) &&
973 buffer_is_zero(cur_buf, cluster_size)) {
974 ret = blk_pwrite_zeroes(blk, cur_addr,
975 cluster_size,
976 BDRV_REQ_MAY_UNMAP);
977 } else {
978 ret = blk_pwrite(blk, cur_addr, cur_buf,
979 cluster_size, 0);
980 }
981 if (ret < 0) {
982 break;
983 }
984 }
985 g_free(buf);
986 }
987
988 if (ret < 0) {
989 return ret;
990 }
991 } else if (flags & BLK_MIG_FLAG_PROGRESS) {
992 if (!banner_printed) {
993 printf("Receiving block device images\n");
994 banner_printed = 1;
995 }
996 printf("Completed %d %%%c", (int)addr,
997 (addr == 100) ? '\n' : '\r');
998 fflush(stdout);
999 } else if (!(flags & BLK_MIG_FLAG_EOS)) {
1000 fprintf(stderr, "Unknown block migration flags: %#x\n", flags);
1001 return -EINVAL;
1002 }
1003 ret = qemu_file_get_error(f);
1004 if (ret != 0) {
1005 return ret;
1006 }
1007 } while (!(flags & BLK_MIG_FLAG_EOS));
1008
1009 return 0;
1010 }
1011
1012 static bool block_is_active(void *opaque)
1013 {
1014 return migrate_use_block();
1015 }
1016
1017 static SaveVMHandlers savevm_block_handlers = {
1018 .save_setup = block_save_setup,
1019 .save_live_iterate = block_save_iterate,
1020 .save_live_complete_precopy = block_save_complete,
1021 .save_live_pending = block_save_pending,
1022 .load_state = block_load,
1023 .save_cleanup = block_migration_cleanup,
1024 .is_active = block_is_active,
1025 };
1026
1027 void blk_mig_init(void)
1028 {
1029 QSIMPLEQ_INIT(&block_mig_state.bmds_list);
1030 QSIMPLEQ_INIT(&block_mig_state.blk_list);
1031 qemu_mutex_init(&block_mig_state.lock);
1032
1033 register_savevm_live("block", 0, 1, &savevm_block_handlers,
1034 &block_mig_state);
1035 }