block: Catch backing files assigned to non-COW drivers
[qemu.git] / block / qed.c
1 /*
2 * QEMU Enhanced Disk Format
3 *
4 * Copyright IBM, Corp. 2010
5 *
6 * Authors:
7 * Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
8 * Anthony Liguori <aliguori@us.ibm.com>
9 *
10 * This work is licensed under the terms of the GNU LGPL, version 2 or later.
11 * See the COPYING.LIB file in the top-level directory.
12 *
13 */
14
15 #include "qemu/timer.h"
16 #include "trace.h"
17 #include "qed.h"
18 #include "qapi/qmp/qerror.h"
19 #include "migration/migration.h"
20
21 static void qed_aio_cancel(BlockDriverAIOCB *blockacb)
22 {
23 QEDAIOCB *acb = (QEDAIOCB *)blockacb;
24 AioContext *aio_context = bdrv_get_aio_context(blockacb->bs);
25 bool finished = false;
26
27 /* Wait for the request to finish */
28 acb->finished = &finished;
29 while (!finished) {
30 aio_poll(aio_context, true);
31 }
32 }
33
34 static const AIOCBInfo qed_aiocb_info = {
35 .aiocb_size = sizeof(QEDAIOCB),
36 .cancel = qed_aio_cancel,
37 };
38
39 static int bdrv_qed_probe(const uint8_t *buf, int buf_size,
40 const char *filename)
41 {
42 const QEDHeader *header = (const QEDHeader *)buf;
43
44 if (buf_size < sizeof(*header)) {
45 return 0;
46 }
47 if (le32_to_cpu(header->magic) != QED_MAGIC) {
48 return 0;
49 }
50 return 100;
51 }
52
53 /**
54 * Check whether an image format is raw
55 *
56 * @fmt: Backing file format, may be NULL
57 */
58 static bool qed_fmt_is_raw(const char *fmt)
59 {
60 return fmt && strcmp(fmt, "raw") == 0;
61 }
62
63 static void qed_header_le_to_cpu(const QEDHeader *le, QEDHeader *cpu)
64 {
65 cpu->magic = le32_to_cpu(le->magic);
66 cpu->cluster_size = le32_to_cpu(le->cluster_size);
67 cpu->table_size = le32_to_cpu(le->table_size);
68 cpu->header_size = le32_to_cpu(le->header_size);
69 cpu->features = le64_to_cpu(le->features);
70 cpu->compat_features = le64_to_cpu(le->compat_features);
71 cpu->autoclear_features = le64_to_cpu(le->autoclear_features);
72 cpu->l1_table_offset = le64_to_cpu(le->l1_table_offset);
73 cpu->image_size = le64_to_cpu(le->image_size);
74 cpu->backing_filename_offset = le32_to_cpu(le->backing_filename_offset);
75 cpu->backing_filename_size = le32_to_cpu(le->backing_filename_size);
76 }
77
78 static void qed_header_cpu_to_le(const QEDHeader *cpu, QEDHeader *le)
79 {
80 le->magic = cpu_to_le32(cpu->magic);
81 le->cluster_size = cpu_to_le32(cpu->cluster_size);
82 le->table_size = cpu_to_le32(cpu->table_size);
83 le->header_size = cpu_to_le32(cpu->header_size);
84 le->features = cpu_to_le64(cpu->features);
85 le->compat_features = cpu_to_le64(cpu->compat_features);
86 le->autoclear_features = cpu_to_le64(cpu->autoclear_features);
87 le->l1_table_offset = cpu_to_le64(cpu->l1_table_offset);
88 le->image_size = cpu_to_le64(cpu->image_size);
89 le->backing_filename_offset = cpu_to_le32(cpu->backing_filename_offset);
90 le->backing_filename_size = cpu_to_le32(cpu->backing_filename_size);
91 }
92
93 int qed_write_header_sync(BDRVQEDState *s)
94 {
95 QEDHeader le;
96 int ret;
97
98 qed_header_cpu_to_le(&s->header, &le);
99 ret = bdrv_pwrite(s->bs->file, 0, &le, sizeof(le));
100 if (ret != sizeof(le)) {
101 return ret;
102 }
103 return 0;
104 }
105
106 typedef struct {
107 GenericCB gencb;
108 BDRVQEDState *s;
109 struct iovec iov;
110 QEMUIOVector qiov;
111 int nsectors;
112 uint8_t *buf;
113 } QEDWriteHeaderCB;
114
115 static void qed_write_header_cb(void *opaque, int ret)
116 {
117 QEDWriteHeaderCB *write_header_cb = opaque;
118
119 qemu_vfree(write_header_cb->buf);
120 gencb_complete(write_header_cb, ret);
121 }
122
123 static void qed_write_header_read_cb(void *opaque, int ret)
124 {
125 QEDWriteHeaderCB *write_header_cb = opaque;
126 BDRVQEDState *s = write_header_cb->s;
127
128 if (ret) {
129 qed_write_header_cb(write_header_cb, ret);
130 return;
131 }
132
133 /* Update header */
134 qed_header_cpu_to_le(&s->header, (QEDHeader *)write_header_cb->buf);
135
136 bdrv_aio_writev(s->bs->file, 0, &write_header_cb->qiov,
137 write_header_cb->nsectors, qed_write_header_cb,
138 write_header_cb);
139 }
140
141 /**
142 * Update header in-place (does not rewrite backing filename or other strings)
143 *
144 * This function only updates known header fields in-place and does not affect
145 * extra data after the QED header.
146 */
147 static void qed_write_header(BDRVQEDState *s, BlockDriverCompletionFunc cb,
148 void *opaque)
149 {
150 /* We must write full sectors for O_DIRECT but cannot necessarily generate
151 * the data following the header if an unrecognized compat feature is
152 * active. Therefore, first read the sectors containing the header, update
153 * them, and write back.
154 */
155
156 int nsectors = (sizeof(QEDHeader) + BDRV_SECTOR_SIZE - 1) /
157 BDRV_SECTOR_SIZE;
158 size_t len = nsectors * BDRV_SECTOR_SIZE;
159 QEDWriteHeaderCB *write_header_cb = gencb_alloc(sizeof(*write_header_cb),
160 cb, opaque);
161
162 write_header_cb->s = s;
163 write_header_cb->nsectors = nsectors;
164 write_header_cb->buf = qemu_blockalign(s->bs, len);
165 write_header_cb->iov.iov_base = write_header_cb->buf;
166 write_header_cb->iov.iov_len = len;
167 qemu_iovec_init_external(&write_header_cb->qiov, &write_header_cb->iov, 1);
168
169 bdrv_aio_readv(s->bs->file, 0, &write_header_cb->qiov, nsectors,
170 qed_write_header_read_cb, write_header_cb);
171 }
172
173 static uint64_t qed_max_image_size(uint32_t cluster_size, uint32_t table_size)
174 {
175 uint64_t table_entries;
176 uint64_t l2_size;
177
178 table_entries = (table_size * cluster_size) / sizeof(uint64_t);
179 l2_size = table_entries * cluster_size;
180
181 return l2_size * table_entries;
182 }
183
184 static bool qed_is_cluster_size_valid(uint32_t cluster_size)
185 {
186 if (cluster_size < QED_MIN_CLUSTER_SIZE ||
187 cluster_size > QED_MAX_CLUSTER_SIZE) {
188 return false;
189 }
190 if (cluster_size & (cluster_size - 1)) {
191 return false; /* not power of 2 */
192 }
193 return true;
194 }
195
196 static bool qed_is_table_size_valid(uint32_t table_size)
197 {
198 if (table_size < QED_MIN_TABLE_SIZE ||
199 table_size > QED_MAX_TABLE_SIZE) {
200 return false;
201 }
202 if (table_size & (table_size - 1)) {
203 return false; /* not power of 2 */
204 }
205 return true;
206 }
207
208 static bool qed_is_image_size_valid(uint64_t image_size, uint32_t cluster_size,
209 uint32_t table_size)
210 {
211 if (image_size % BDRV_SECTOR_SIZE != 0) {
212 return false; /* not multiple of sector size */
213 }
214 if (image_size > qed_max_image_size(cluster_size, table_size)) {
215 return false; /* image is too large */
216 }
217 return true;
218 }
219
220 /**
221 * Read a string of known length from the image file
222 *
223 * @file: Image file
224 * @offset: File offset to start of string, in bytes
225 * @n: String length in bytes
226 * @buf: Destination buffer
227 * @buflen: Destination buffer length in bytes
228 * @ret: 0 on success, -errno on failure
229 *
230 * The string is NUL-terminated.
231 */
232 static int qed_read_string(BlockDriverState *file, uint64_t offset, size_t n,
233 char *buf, size_t buflen)
234 {
235 int ret;
236 if (n >= buflen) {
237 return -EINVAL;
238 }
239 ret = bdrv_pread(file, offset, buf, n);
240 if (ret < 0) {
241 return ret;
242 }
243 buf[n] = '\0';
244 return 0;
245 }
246
247 /**
248 * Allocate new clusters
249 *
250 * @s: QED state
251 * @n: Number of contiguous clusters to allocate
252 * @ret: Offset of first allocated cluster
253 *
254 * This function only produces the offset where the new clusters should be
255 * written. It updates BDRVQEDState but does not make any changes to the image
256 * file.
257 */
258 static uint64_t qed_alloc_clusters(BDRVQEDState *s, unsigned int n)
259 {
260 uint64_t offset = s->file_size;
261 s->file_size += n * s->header.cluster_size;
262 return offset;
263 }
264
265 QEDTable *qed_alloc_table(BDRVQEDState *s)
266 {
267 /* Honor O_DIRECT memory alignment requirements */
268 return qemu_blockalign(s->bs,
269 s->header.cluster_size * s->header.table_size);
270 }
271
272 /**
273 * Allocate a new zeroed L2 table
274 */
275 static CachedL2Table *qed_new_l2_table(BDRVQEDState *s)
276 {
277 CachedL2Table *l2_table = qed_alloc_l2_cache_entry(&s->l2_cache);
278
279 l2_table->table = qed_alloc_table(s);
280 l2_table->offset = qed_alloc_clusters(s, s->header.table_size);
281
282 memset(l2_table->table->offsets, 0,
283 s->header.cluster_size * s->header.table_size);
284 return l2_table;
285 }
286
287 static void qed_aio_next_io(void *opaque, int ret);
288
289 static void qed_plug_allocating_write_reqs(BDRVQEDState *s)
290 {
291 assert(!s->allocating_write_reqs_plugged);
292
293 s->allocating_write_reqs_plugged = true;
294 }
295
296 static void qed_unplug_allocating_write_reqs(BDRVQEDState *s)
297 {
298 QEDAIOCB *acb;
299
300 assert(s->allocating_write_reqs_plugged);
301
302 s->allocating_write_reqs_plugged = false;
303
304 acb = QSIMPLEQ_FIRST(&s->allocating_write_reqs);
305 if (acb) {
306 qed_aio_next_io(acb, 0);
307 }
308 }
309
310 static void qed_finish_clear_need_check(void *opaque, int ret)
311 {
312 /* Do nothing */
313 }
314
315 static void qed_flush_after_clear_need_check(void *opaque, int ret)
316 {
317 BDRVQEDState *s = opaque;
318
319 bdrv_aio_flush(s->bs, qed_finish_clear_need_check, s);
320
321 /* No need to wait until flush completes */
322 qed_unplug_allocating_write_reqs(s);
323 }
324
325 static void qed_clear_need_check(void *opaque, int ret)
326 {
327 BDRVQEDState *s = opaque;
328
329 if (ret) {
330 qed_unplug_allocating_write_reqs(s);
331 return;
332 }
333
334 s->header.features &= ~QED_F_NEED_CHECK;
335 qed_write_header(s, qed_flush_after_clear_need_check, s);
336 }
337
338 static void qed_need_check_timer_cb(void *opaque)
339 {
340 BDRVQEDState *s = opaque;
341
342 /* The timer should only fire when allocating writes have drained */
343 assert(!QSIMPLEQ_FIRST(&s->allocating_write_reqs));
344
345 trace_qed_need_check_timer_cb(s);
346
347 qed_plug_allocating_write_reqs(s);
348
349 /* Ensure writes are on disk before clearing flag */
350 bdrv_aio_flush(s->bs, qed_clear_need_check, s);
351 }
352
353 static void qed_start_need_check_timer(BDRVQEDState *s)
354 {
355 trace_qed_start_need_check_timer(s);
356
357 /* Use QEMU_CLOCK_VIRTUAL so we don't alter the image file while suspended for
358 * migration.
359 */
360 timer_mod(s->need_check_timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
361 get_ticks_per_sec() * QED_NEED_CHECK_TIMEOUT);
362 }
363
364 /* It's okay to call this multiple times or when no timer is started */
365 static void qed_cancel_need_check_timer(BDRVQEDState *s)
366 {
367 trace_qed_cancel_need_check_timer(s);
368 timer_del(s->need_check_timer);
369 }
370
371 static void bdrv_qed_rebind(BlockDriverState *bs)
372 {
373 BDRVQEDState *s = bs->opaque;
374 s->bs = bs;
375 }
376
377 static void bdrv_qed_detach_aio_context(BlockDriverState *bs)
378 {
379 BDRVQEDState *s = bs->opaque;
380
381 qed_cancel_need_check_timer(s);
382 timer_free(s->need_check_timer);
383 }
384
385 static void bdrv_qed_attach_aio_context(BlockDriverState *bs,
386 AioContext *new_context)
387 {
388 BDRVQEDState *s = bs->opaque;
389
390 s->need_check_timer = aio_timer_new(new_context,
391 QEMU_CLOCK_VIRTUAL, SCALE_NS,
392 qed_need_check_timer_cb, s);
393 if (s->header.features & QED_F_NEED_CHECK) {
394 qed_start_need_check_timer(s);
395 }
396 }
397
398 static int bdrv_qed_open(BlockDriverState *bs, QDict *options, int flags,
399 Error **errp)
400 {
401 BDRVQEDState *s = bs->opaque;
402 QEDHeader le_header;
403 int64_t file_size;
404 int ret;
405
406 s->bs = bs;
407 QSIMPLEQ_INIT(&s->allocating_write_reqs);
408
409 ret = bdrv_pread(bs->file, 0, &le_header, sizeof(le_header));
410 if (ret < 0) {
411 return ret;
412 }
413 qed_header_le_to_cpu(&le_header, &s->header);
414
415 if (s->header.magic != QED_MAGIC) {
416 error_setg(errp, "Image not in QED format");
417 return -EINVAL;
418 }
419 if (s->header.features & ~QED_FEATURE_MASK) {
420 /* image uses unsupported feature bits */
421 char buf[64];
422 snprintf(buf, sizeof(buf), "%" PRIx64,
423 s->header.features & ~QED_FEATURE_MASK);
424 error_set(errp, QERR_UNKNOWN_BLOCK_FORMAT_FEATURE,
425 bs->device_name, "QED", buf);
426 return -ENOTSUP;
427 }
428 if (!qed_is_cluster_size_valid(s->header.cluster_size)) {
429 return -EINVAL;
430 }
431
432 /* Round down file size to the last cluster */
433 file_size = bdrv_getlength(bs->file);
434 if (file_size < 0) {
435 return file_size;
436 }
437 s->file_size = qed_start_of_cluster(s, file_size);
438
439 if (!qed_is_table_size_valid(s->header.table_size)) {
440 return -EINVAL;
441 }
442 if (!qed_is_image_size_valid(s->header.image_size,
443 s->header.cluster_size,
444 s->header.table_size)) {
445 return -EINVAL;
446 }
447 if (!qed_check_table_offset(s, s->header.l1_table_offset)) {
448 return -EINVAL;
449 }
450
451 s->table_nelems = (s->header.cluster_size * s->header.table_size) /
452 sizeof(uint64_t);
453 s->l2_shift = ffs(s->header.cluster_size) - 1;
454 s->l2_mask = s->table_nelems - 1;
455 s->l1_shift = s->l2_shift + ffs(s->table_nelems) - 1;
456
457 if ((s->header.features & QED_F_BACKING_FILE)) {
458 if ((uint64_t)s->header.backing_filename_offset +
459 s->header.backing_filename_size >
460 s->header.cluster_size * s->header.header_size) {
461 return -EINVAL;
462 }
463
464 ret = qed_read_string(bs->file, s->header.backing_filename_offset,
465 s->header.backing_filename_size, bs->backing_file,
466 sizeof(bs->backing_file));
467 if (ret < 0) {
468 return ret;
469 }
470
471 if (s->header.features & QED_F_BACKING_FORMAT_NO_PROBE) {
472 pstrcpy(bs->backing_format, sizeof(bs->backing_format), "raw");
473 }
474 }
475
476 /* Reset unknown autoclear feature bits. This is a backwards
477 * compatibility mechanism that allows images to be opened by older
478 * programs, which "knock out" unknown feature bits. When an image is
479 * opened by a newer program again it can detect that the autoclear
480 * feature is no longer valid.
481 */
482 if ((s->header.autoclear_features & ~QED_AUTOCLEAR_FEATURE_MASK) != 0 &&
483 !bdrv_is_read_only(bs->file) && !(flags & BDRV_O_INCOMING)) {
484 s->header.autoclear_features &= QED_AUTOCLEAR_FEATURE_MASK;
485
486 ret = qed_write_header_sync(s);
487 if (ret) {
488 return ret;
489 }
490
491 /* From here on only known autoclear feature bits are valid */
492 bdrv_flush(bs->file);
493 }
494
495 s->l1_table = qed_alloc_table(s);
496 qed_init_l2_cache(&s->l2_cache);
497
498 ret = qed_read_l1_table_sync(s);
499 if (ret) {
500 goto out;
501 }
502
503 /* If image was not closed cleanly, check consistency */
504 if (!(flags & BDRV_O_CHECK) && (s->header.features & QED_F_NEED_CHECK)) {
505 /* Read-only images cannot be fixed. There is no risk of corruption
506 * since write operations are not possible. Therefore, allow
507 * potentially inconsistent images to be opened read-only. This can
508 * aid data recovery from an otherwise inconsistent image.
509 */
510 if (!bdrv_is_read_only(bs->file) &&
511 !(flags & BDRV_O_INCOMING)) {
512 BdrvCheckResult result = {0};
513
514 ret = qed_check(s, &result, true);
515 if (ret) {
516 goto out;
517 }
518 }
519 }
520
521 bdrv_qed_attach_aio_context(bs, bdrv_get_aio_context(bs));
522
523 out:
524 if (ret) {
525 qed_free_l2_cache(&s->l2_cache);
526 qemu_vfree(s->l1_table);
527 }
528 return ret;
529 }
530
531 static int bdrv_qed_refresh_limits(BlockDriverState *bs)
532 {
533 BDRVQEDState *s = bs->opaque;
534
535 bs->bl.write_zeroes_alignment = s->header.cluster_size >> BDRV_SECTOR_BITS;
536
537 return 0;
538 }
539
540 /* We have nothing to do for QED reopen, stubs just return
541 * success */
542 static int bdrv_qed_reopen_prepare(BDRVReopenState *state,
543 BlockReopenQueue *queue, Error **errp)
544 {
545 return 0;
546 }
547
548 static void bdrv_qed_close(BlockDriverState *bs)
549 {
550 BDRVQEDState *s = bs->opaque;
551
552 bdrv_qed_detach_aio_context(bs);
553
554 /* Ensure writes reach stable storage */
555 bdrv_flush(bs->file);
556
557 /* Clean shutdown, no check required on next open */
558 if (s->header.features & QED_F_NEED_CHECK) {
559 s->header.features &= ~QED_F_NEED_CHECK;
560 qed_write_header_sync(s);
561 }
562
563 qed_free_l2_cache(&s->l2_cache);
564 qemu_vfree(s->l1_table);
565 }
566
567 static int qed_create(const char *filename, uint32_t cluster_size,
568 uint64_t image_size, uint32_t table_size,
569 const char *backing_file, const char *backing_fmt,
570 Error **errp)
571 {
572 QEDHeader header = {
573 .magic = QED_MAGIC,
574 .cluster_size = cluster_size,
575 .table_size = table_size,
576 .header_size = 1,
577 .features = 0,
578 .compat_features = 0,
579 .l1_table_offset = cluster_size,
580 .image_size = image_size,
581 };
582 QEDHeader le_header;
583 uint8_t *l1_table = NULL;
584 size_t l1_size = header.cluster_size * header.table_size;
585 Error *local_err = NULL;
586 int ret = 0;
587 BlockDriverState *bs;
588
589 ret = bdrv_create_file(filename, NULL, &local_err);
590 if (ret < 0) {
591 error_propagate(errp, local_err);
592 return ret;
593 }
594
595 bs = NULL;
596 ret = bdrv_open(&bs, filename, NULL, NULL,
597 BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_PROTOCOL, NULL,
598 &local_err);
599 if (ret < 0) {
600 error_propagate(errp, local_err);
601 return ret;
602 }
603
604 /* File must start empty and grow, check truncate is supported */
605 ret = bdrv_truncate(bs, 0);
606 if (ret < 0) {
607 goto out;
608 }
609
610 if (backing_file) {
611 header.features |= QED_F_BACKING_FILE;
612 header.backing_filename_offset = sizeof(le_header);
613 header.backing_filename_size = strlen(backing_file);
614
615 if (qed_fmt_is_raw(backing_fmt)) {
616 header.features |= QED_F_BACKING_FORMAT_NO_PROBE;
617 }
618 }
619
620 qed_header_cpu_to_le(&header, &le_header);
621 ret = bdrv_pwrite(bs, 0, &le_header, sizeof(le_header));
622 if (ret < 0) {
623 goto out;
624 }
625 ret = bdrv_pwrite(bs, sizeof(le_header), backing_file,
626 header.backing_filename_size);
627 if (ret < 0) {
628 goto out;
629 }
630
631 l1_table = g_malloc0(l1_size);
632 ret = bdrv_pwrite(bs, header.l1_table_offset, l1_table, l1_size);
633 if (ret < 0) {
634 goto out;
635 }
636
637 ret = 0; /* success */
638 out:
639 g_free(l1_table);
640 bdrv_unref(bs);
641 return ret;
642 }
643
644 static int bdrv_qed_create(const char *filename, QemuOpts *opts, Error **errp)
645 {
646 uint64_t image_size = 0;
647 uint32_t cluster_size = QED_DEFAULT_CLUSTER_SIZE;
648 uint32_t table_size = QED_DEFAULT_TABLE_SIZE;
649 char *backing_file = NULL;
650 char *backing_fmt = NULL;
651 int ret;
652
653 image_size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0);
654 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE);
655 backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT);
656 cluster_size = qemu_opt_get_size_del(opts,
657 BLOCK_OPT_CLUSTER_SIZE,
658 QED_DEFAULT_CLUSTER_SIZE);
659 table_size = qemu_opt_get_size_del(opts, BLOCK_OPT_TABLE_SIZE,
660 QED_DEFAULT_TABLE_SIZE);
661
662 if (!qed_is_cluster_size_valid(cluster_size)) {
663 error_setg(errp, "QED cluster size must be within range [%u, %u] "
664 "and power of 2",
665 QED_MIN_CLUSTER_SIZE, QED_MAX_CLUSTER_SIZE);
666 ret = -EINVAL;
667 goto finish;
668 }
669 if (!qed_is_table_size_valid(table_size)) {
670 error_setg(errp, "QED table size must be within range [%u, %u] "
671 "and power of 2",
672 QED_MIN_TABLE_SIZE, QED_MAX_TABLE_SIZE);
673 ret = -EINVAL;
674 goto finish;
675 }
676 if (!qed_is_image_size_valid(image_size, cluster_size, table_size)) {
677 error_setg(errp, "QED image size must be a non-zero multiple of "
678 "cluster size and less than %" PRIu64 " bytes",
679 qed_max_image_size(cluster_size, table_size));
680 ret = -EINVAL;
681 goto finish;
682 }
683
684 ret = qed_create(filename, cluster_size, image_size, table_size,
685 backing_file, backing_fmt, errp);
686
687 finish:
688 g_free(backing_file);
689 g_free(backing_fmt);
690 return ret;
691 }
692
693 typedef struct {
694 BlockDriverState *bs;
695 Coroutine *co;
696 uint64_t pos;
697 int64_t status;
698 int *pnum;
699 } QEDIsAllocatedCB;
700
701 static void qed_is_allocated_cb(void *opaque, int ret, uint64_t offset, size_t len)
702 {
703 QEDIsAllocatedCB *cb = opaque;
704 BDRVQEDState *s = cb->bs->opaque;
705 *cb->pnum = len / BDRV_SECTOR_SIZE;
706 switch (ret) {
707 case QED_CLUSTER_FOUND:
708 offset |= qed_offset_into_cluster(s, cb->pos);
709 cb->status = BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | offset;
710 break;
711 case QED_CLUSTER_ZERO:
712 cb->status = BDRV_BLOCK_ZERO;
713 break;
714 case QED_CLUSTER_L2:
715 case QED_CLUSTER_L1:
716 cb->status = 0;
717 break;
718 default:
719 assert(ret < 0);
720 cb->status = ret;
721 break;
722 }
723
724 if (cb->co) {
725 qemu_coroutine_enter(cb->co, NULL);
726 }
727 }
728
729 static int64_t coroutine_fn bdrv_qed_co_get_block_status(BlockDriverState *bs,
730 int64_t sector_num,
731 int nb_sectors, int *pnum)
732 {
733 BDRVQEDState *s = bs->opaque;
734 size_t len = (size_t)nb_sectors * BDRV_SECTOR_SIZE;
735 QEDIsAllocatedCB cb = {
736 .bs = bs,
737 .pos = (uint64_t)sector_num * BDRV_SECTOR_SIZE,
738 .status = BDRV_BLOCK_OFFSET_MASK,
739 .pnum = pnum,
740 };
741 QEDRequest request = { .l2_table = NULL };
742
743 qed_find_cluster(s, &request, cb.pos, len, qed_is_allocated_cb, &cb);
744
745 /* Now sleep if the callback wasn't invoked immediately */
746 while (cb.status == BDRV_BLOCK_OFFSET_MASK) {
747 cb.co = qemu_coroutine_self();
748 qemu_coroutine_yield();
749 }
750
751 qed_unref_l2_cache_entry(request.l2_table);
752
753 return cb.status;
754 }
755
756 static BDRVQEDState *acb_to_s(QEDAIOCB *acb)
757 {
758 return acb->common.bs->opaque;
759 }
760
761 /**
762 * Read from the backing file or zero-fill if no backing file
763 *
764 * @s: QED state
765 * @pos: Byte position in device
766 * @qiov: Destination I/O vector
767 * @cb: Completion function
768 * @opaque: User data for completion function
769 *
770 * This function reads qiov->size bytes starting at pos from the backing file.
771 * If there is no backing file then zeroes are read.
772 */
773 static void qed_read_backing_file(BDRVQEDState *s, uint64_t pos,
774 QEMUIOVector *qiov,
775 BlockDriverCompletionFunc *cb, void *opaque)
776 {
777 uint64_t backing_length = 0;
778 size_t size;
779
780 /* If there is a backing file, get its length. Treat the absence of a
781 * backing file like a zero length backing file.
782 */
783 if (s->bs->backing_hd) {
784 int64_t l = bdrv_getlength(s->bs->backing_hd);
785 if (l < 0) {
786 cb(opaque, l);
787 return;
788 }
789 backing_length = l;
790 }
791
792 /* Zero all sectors if reading beyond the end of the backing file */
793 if (pos >= backing_length ||
794 pos + qiov->size > backing_length) {
795 qemu_iovec_memset(qiov, 0, 0, qiov->size);
796 }
797
798 /* Complete now if there are no backing file sectors to read */
799 if (pos >= backing_length) {
800 cb(opaque, 0);
801 return;
802 }
803
804 /* If the read straddles the end of the backing file, shorten it */
805 size = MIN((uint64_t)backing_length - pos, qiov->size);
806
807 BLKDBG_EVENT(s->bs->file, BLKDBG_READ_BACKING_AIO);
808 bdrv_aio_readv(s->bs->backing_hd, pos / BDRV_SECTOR_SIZE,
809 qiov, size / BDRV_SECTOR_SIZE, cb, opaque);
810 }
811
812 typedef struct {
813 GenericCB gencb;
814 BDRVQEDState *s;
815 QEMUIOVector qiov;
816 struct iovec iov;
817 uint64_t offset;
818 } CopyFromBackingFileCB;
819
820 static void qed_copy_from_backing_file_cb(void *opaque, int ret)
821 {
822 CopyFromBackingFileCB *copy_cb = opaque;
823 qemu_vfree(copy_cb->iov.iov_base);
824 gencb_complete(&copy_cb->gencb, ret);
825 }
826
827 static void qed_copy_from_backing_file_write(void *opaque, int ret)
828 {
829 CopyFromBackingFileCB *copy_cb = opaque;
830 BDRVQEDState *s = copy_cb->s;
831
832 if (ret) {
833 qed_copy_from_backing_file_cb(copy_cb, ret);
834 return;
835 }
836
837 BLKDBG_EVENT(s->bs->file, BLKDBG_COW_WRITE);
838 bdrv_aio_writev(s->bs->file, copy_cb->offset / BDRV_SECTOR_SIZE,
839 &copy_cb->qiov, copy_cb->qiov.size / BDRV_SECTOR_SIZE,
840 qed_copy_from_backing_file_cb, copy_cb);
841 }
842
843 /**
844 * Copy data from backing file into the image
845 *
846 * @s: QED state
847 * @pos: Byte position in device
848 * @len: Number of bytes
849 * @offset: Byte offset in image file
850 * @cb: Completion function
851 * @opaque: User data for completion function
852 */
853 static void qed_copy_from_backing_file(BDRVQEDState *s, uint64_t pos,
854 uint64_t len, uint64_t offset,
855 BlockDriverCompletionFunc *cb,
856 void *opaque)
857 {
858 CopyFromBackingFileCB *copy_cb;
859
860 /* Skip copy entirely if there is no work to do */
861 if (len == 0) {
862 cb(opaque, 0);
863 return;
864 }
865
866 copy_cb = gencb_alloc(sizeof(*copy_cb), cb, opaque);
867 copy_cb->s = s;
868 copy_cb->offset = offset;
869 copy_cb->iov.iov_base = qemu_blockalign(s->bs, len);
870 copy_cb->iov.iov_len = len;
871 qemu_iovec_init_external(&copy_cb->qiov, &copy_cb->iov, 1);
872
873 qed_read_backing_file(s, pos, &copy_cb->qiov,
874 qed_copy_from_backing_file_write, copy_cb);
875 }
876
877 /**
878 * Link one or more contiguous clusters into a table
879 *
880 * @s: QED state
881 * @table: L2 table
882 * @index: First cluster index
883 * @n: Number of contiguous clusters
884 * @cluster: First cluster offset
885 *
886 * The cluster offset may be an allocated byte offset in the image file, the
887 * zero cluster marker, or the unallocated cluster marker.
888 */
889 static void qed_update_l2_table(BDRVQEDState *s, QEDTable *table, int index,
890 unsigned int n, uint64_t cluster)
891 {
892 int i;
893 for (i = index; i < index + n; i++) {
894 table->offsets[i] = cluster;
895 if (!qed_offset_is_unalloc_cluster(cluster) &&
896 !qed_offset_is_zero_cluster(cluster)) {
897 cluster += s->header.cluster_size;
898 }
899 }
900 }
901
902 static void qed_aio_complete_bh(void *opaque)
903 {
904 QEDAIOCB *acb = opaque;
905 BlockDriverCompletionFunc *cb = acb->common.cb;
906 void *user_opaque = acb->common.opaque;
907 int ret = acb->bh_ret;
908 bool *finished = acb->finished;
909
910 qemu_bh_delete(acb->bh);
911 qemu_aio_release(acb);
912
913 /* Invoke callback */
914 cb(user_opaque, ret);
915
916 /* Signal cancel completion */
917 if (finished) {
918 *finished = true;
919 }
920 }
921
922 static void qed_aio_complete(QEDAIOCB *acb, int ret)
923 {
924 BDRVQEDState *s = acb_to_s(acb);
925
926 trace_qed_aio_complete(s, acb, ret);
927
928 /* Free resources */
929 qemu_iovec_destroy(&acb->cur_qiov);
930 qed_unref_l2_cache_entry(acb->request.l2_table);
931
932 /* Free the buffer we may have allocated for zero writes */
933 if (acb->flags & QED_AIOCB_ZERO) {
934 qemu_vfree(acb->qiov->iov[0].iov_base);
935 acb->qiov->iov[0].iov_base = NULL;
936 }
937
938 /* Arrange for a bh to invoke the completion function */
939 acb->bh_ret = ret;
940 acb->bh = aio_bh_new(bdrv_get_aio_context(acb->common.bs),
941 qed_aio_complete_bh, acb);
942 qemu_bh_schedule(acb->bh);
943
944 /* Start next allocating write request waiting behind this one. Note that
945 * requests enqueue themselves when they first hit an unallocated cluster
946 * but they wait until the entire request is finished before waking up the
947 * next request in the queue. This ensures that we don't cycle through
948 * requests multiple times but rather finish one at a time completely.
949 */
950 if (acb == QSIMPLEQ_FIRST(&s->allocating_write_reqs)) {
951 QSIMPLEQ_REMOVE_HEAD(&s->allocating_write_reqs, next);
952 acb = QSIMPLEQ_FIRST(&s->allocating_write_reqs);
953 if (acb) {
954 qed_aio_next_io(acb, 0);
955 } else if (s->header.features & QED_F_NEED_CHECK) {
956 qed_start_need_check_timer(s);
957 }
958 }
959 }
960
961 /**
962 * Commit the current L2 table to the cache
963 */
964 static void qed_commit_l2_update(void *opaque, int ret)
965 {
966 QEDAIOCB *acb = opaque;
967 BDRVQEDState *s = acb_to_s(acb);
968 CachedL2Table *l2_table = acb->request.l2_table;
969 uint64_t l2_offset = l2_table->offset;
970
971 qed_commit_l2_cache_entry(&s->l2_cache, l2_table);
972
973 /* This is guaranteed to succeed because we just committed the entry to the
974 * cache.
975 */
976 acb->request.l2_table = qed_find_l2_cache_entry(&s->l2_cache, l2_offset);
977 assert(acb->request.l2_table != NULL);
978
979 qed_aio_next_io(opaque, ret);
980 }
981
982 /**
983 * Update L1 table with new L2 table offset and write it out
984 */
985 static void qed_aio_write_l1_update(void *opaque, int ret)
986 {
987 QEDAIOCB *acb = opaque;
988 BDRVQEDState *s = acb_to_s(acb);
989 int index;
990
991 if (ret) {
992 qed_aio_complete(acb, ret);
993 return;
994 }
995
996 index = qed_l1_index(s, acb->cur_pos);
997 s->l1_table->offsets[index] = acb->request.l2_table->offset;
998
999 qed_write_l1_table(s, index, 1, qed_commit_l2_update, acb);
1000 }
1001
1002 /**
1003 * Update L2 table with new cluster offsets and write them out
1004 */
1005 static void qed_aio_write_l2_update(QEDAIOCB *acb, int ret, uint64_t offset)
1006 {
1007 BDRVQEDState *s = acb_to_s(acb);
1008 bool need_alloc = acb->find_cluster_ret == QED_CLUSTER_L1;
1009 int index;
1010
1011 if (ret) {
1012 goto err;
1013 }
1014
1015 if (need_alloc) {
1016 qed_unref_l2_cache_entry(acb->request.l2_table);
1017 acb->request.l2_table = qed_new_l2_table(s);
1018 }
1019
1020 index = qed_l2_index(s, acb->cur_pos);
1021 qed_update_l2_table(s, acb->request.l2_table->table, index, acb->cur_nclusters,
1022 offset);
1023
1024 if (need_alloc) {
1025 /* Write out the whole new L2 table */
1026 qed_write_l2_table(s, &acb->request, 0, s->table_nelems, true,
1027 qed_aio_write_l1_update, acb);
1028 } else {
1029 /* Write out only the updated part of the L2 table */
1030 qed_write_l2_table(s, &acb->request, index, acb->cur_nclusters, false,
1031 qed_aio_next_io, acb);
1032 }
1033 return;
1034
1035 err:
1036 qed_aio_complete(acb, ret);
1037 }
1038
1039 static void qed_aio_write_l2_update_cb(void *opaque, int ret)
1040 {
1041 QEDAIOCB *acb = opaque;
1042 qed_aio_write_l2_update(acb, ret, acb->cur_cluster);
1043 }
1044
1045 /**
1046 * Flush new data clusters before updating the L2 table
1047 *
1048 * This flush is necessary when a backing file is in use. A crash during an
1049 * allocating write could result in empty clusters in the image. If the write
1050 * only touched a subregion of the cluster, then backing image sectors have
1051 * been lost in the untouched region. The solution is to flush after writing a
1052 * new data cluster and before updating the L2 table.
1053 */
1054 static void qed_aio_write_flush_before_l2_update(void *opaque, int ret)
1055 {
1056 QEDAIOCB *acb = opaque;
1057 BDRVQEDState *s = acb_to_s(acb);
1058
1059 if (!bdrv_aio_flush(s->bs->file, qed_aio_write_l2_update_cb, opaque)) {
1060 qed_aio_complete(acb, -EIO);
1061 }
1062 }
1063
1064 /**
1065 * Write data to the image file
1066 */
1067 static void qed_aio_write_main(void *opaque, int ret)
1068 {
1069 QEDAIOCB *acb = opaque;
1070 BDRVQEDState *s = acb_to_s(acb);
1071 uint64_t offset = acb->cur_cluster +
1072 qed_offset_into_cluster(s, acb->cur_pos);
1073 BlockDriverCompletionFunc *next_fn;
1074
1075 trace_qed_aio_write_main(s, acb, ret, offset, acb->cur_qiov.size);
1076
1077 if (ret) {
1078 qed_aio_complete(acb, ret);
1079 return;
1080 }
1081
1082 if (acb->find_cluster_ret == QED_CLUSTER_FOUND) {
1083 next_fn = qed_aio_next_io;
1084 } else {
1085 if (s->bs->backing_hd) {
1086 next_fn = qed_aio_write_flush_before_l2_update;
1087 } else {
1088 next_fn = qed_aio_write_l2_update_cb;
1089 }
1090 }
1091
1092 BLKDBG_EVENT(s->bs->file, BLKDBG_WRITE_AIO);
1093 bdrv_aio_writev(s->bs->file, offset / BDRV_SECTOR_SIZE,
1094 &acb->cur_qiov, acb->cur_qiov.size / BDRV_SECTOR_SIZE,
1095 next_fn, acb);
1096 }
1097
1098 /**
1099 * Populate back untouched region of new data cluster
1100 */
1101 static void qed_aio_write_postfill(void *opaque, int ret)
1102 {
1103 QEDAIOCB *acb = opaque;
1104 BDRVQEDState *s = acb_to_s(acb);
1105 uint64_t start = acb->cur_pos + acb->cur_qiov.size;
1106 uint64_t len =
1107 qed_start_of_cluster(s, start + s->header.cluster_size - 1) - start;
1108 uint64_t offset = acb->cur_cluster +
1109 qed_offset_into_cluster(s, acb->cur_pos) +
1110 acb->cur_qiov.size;
1111
1112 if (ret) {
1113 qed_aio_complete(acb, ret);
1114 return;
1115 }
1116
1117 trace_qed_aio_write_postfill(s, acb, start, len, offset);
1118 qed_copy_from_backing_file(s, start, len, offset,
1119 qed_aio_write_main, acb);
1120 }
1121
1122 /**
1123 * Populate front untouched region of new data cluster
1124 */
1125 static void qed_aio_write_prefill(void *opaque, int ret)
1126 {
1127 QEDAIOCB *acb = opaque;
1128 BDRVQEDState *s = acb_to_s(acb);
1129 uint64_t start = qed_start_of_cluster(s, acb->cur_pos);
1130 uint64_t len = qed_offset_into_cluster(s, acb->cur_pos);
1131
1132 trace_qed_aio_write_prefill(s, acb, start, len, acb->cur_cluster);
1133 qed_copy_from_backing_file(s, start, len, acb->cur_cluster,
1134 qed_aio_write_postfill, acb);
1135 }
1136
1137 /**
1138 * Check if the QED_F_NEED_CHECK bit should be set during allocating write
1139 */
1140 static bool qed_should_set_need_check(BDRVQEDState *s)
1141 {
1142 /* The flush before L2 update path ensures consistency */
1143 if (s->bs->backing_hd) {
1144 return false;
1145 }
1146
1147 return !(s->header.features & QED_F_NEED_CHECK);
1148 }
1149
1150 static void qed_aio_write_zero_cluster(void *opaque, int ret)
1151 {
1152 QEDAIOCB *acb = opaque;
1153
1154 if (ret) {
1155 qed_aio_complete(acb, ret);
1156 return;
1157 }
1158
1159 qed_aio_write_l2_update(acb, 0, 1);
1160 }
1161
1162 /**
1163 * Write new data cluster
1164 *
1165 * @acb: Write request
1166 * @len: Length in bytes
1167 *
1168 * This path is taken when writing to previously unallocated clusters.
1169 */
1170 static void qed_aio_write_alloc(QEDAIOCB *acb, size_t len)
1171 {
1172 BDRVQEDState *s = acb_to_s(acb);
1173 BlockDriverCompletionFunc *cb;
1174
1175 /* Cancel timer when the first allocating request comes in */
1176 if (QSIMPLEQ_EMPTY(&s->allocating_write_reqs)) {
1177 qed_cancel_need_check_timer(s);
1178 }
1179
1180 /* Freeze this request if another allocating write is in progress */
1181 if (acb != QSIMPLEQ_FIRST(&s->allocating_write_reqs)) {
1182 QSIMPLEQ_INSERT_TAIL(&s->allocating_write_reqs, acb, next);
1183 }
1184 if (acb != QSIMPLEQ_FIRST(&s->allocating_write_reqs) ||
1185 s->allocating_write_reqs_plugged) {
1186 return; /* wait for existing request to finish */
1187 }
1188
1189 acb->cur_nclusters = qed_bytes_to_clusters(s,
1190 qed_offset_into_cluster(s, acb->cur_pos) + len);
1191 qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len);
1192
1193 if (acb->flags & QED_AIOCB_ZERO) {
1194 /* Skip ahead if the clusters are already zero */
1195 if (acb->find_cluster_ret == QED_CLUSTER_ZERO) {
1196 qed_aio_next_io(acb, 0);
1197 return;
1198 }
1199
1200 cb = qed_aio_write_zero_cluster;
1201 } else {
1202 cb = qed_aio_write_prefill;
1203 acb->cur_cluster = qed_alloc_clusters(s, acb->cur_nclusters);
1204 }
1205
1206 if (qed_should_set_need_check(s)) {
1207 s->header.features |= QED_F_NEED_CHECK;
1208 qed_write_header(s, cb, acb);
1209 } else {
1210 cb(acb, 0);
1211 }
1212 }
1213
1214 /**
1215 * Write data cluster in place
1216 *
1217 * @acb: Write request
1218 * @offset: Cluster offset in bytes
1219 * @len: Length in bytes
1220 *
1221 * This path is taken when writing to already allocated clusters.
1222 */
1223 static void qed_aio_write_inplace(QEDAIOCB *acb, uint64_t offset, size_t len)
1224 {
1225 /* Allocate buffer for zero writes */
1226 if (acb->flags & QED_AIOCB_ZERO) {
1227 struct iovec *iov = acb->qiov->iov;
1228
1229 if (!iov->iov_base) {
1230 iov->iov_base = qemu_blockalign(acb->common.bs, iov->iov_len);
1231 memset(iov->iov_base, 0, iov->iov_len);
1232 }
1233 }
1234
1235 /* Calculate the I/O vector */
1236 acb->cur_cluster = offset;
1237 qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len);
1238
1239 /* Do the actual write */
1240 qed_aio_write_main(acb, 0);
1241 }
1242
1243 /**
1244 * Write data cluster
1245 *
1246 * @opaque: Write request
1247 * @ret: QED_CLUSTER_FOUND, QED_CLUSTER_L2, QED_CLUSTER_L1,
1248 * or -errno
1249 * @offset: Cluster offset in bytes
1250 * @len: Length in bytes
1251 *
1252 * Callback from qed_find_cluster().
1253 */
1254 static void qed_aio_write_data(void *opaque, int ret,
1255 uint64_t offset, size_t len)
1256 {
1257 QEDAIOCB *acb = opaque;
1258
1259 trace_qed_aio_write_data(acb_to_s(acb), acb, ret, offset, len);
1260
1261 acb->find_cluster_ret = ret;
1262
1263 switch (ret) {
1264 case QED_CLUSTER_FOUND:
1265 qed_aio_write_inplace(acb, offset, len);
1266 break;
1267
1268 case QED_CLUSTER_L2:
1269 case QED_CLUSTER_L1:
1270 case QED_CLUSTER_ZERO:
1271 qed_aio_write_alloc(acb, len);
1272 break;
1273
1274 default:
1275 qed_aio_complete(acb, ret);
1276 break;
1277 }
1278 }
1279
1280 /**
1281 * Read data cluster
1282 *
1283 * @opaque: Read request
1284 * @ret: QED_CLUSTER_FOUND, QED_CLUSTER_L2, QED_CLUSTER_L1,
1285 * or -errno
1286 * @offset: Cluster offset in bytes
1287 * @len: Length in bytes
1288 *
1289 * Callback from qed_find_cluster().
1290 */
1291 static void qed_aio_read_data(void *opaque, int ret,
1292 uint64_t offset, size_t len)
1293 {
1294 QEDAIOCB *acb = opaque;
1295 BDRVQEDState *s = acb_to_s(acb);
1296 BlockDriverState *bs = acb->common.bs;
1297
1298 /* Adjust offset into cluster */
1299 offset += qed_offset_into_cluster(s, acb->cur_pos);
1300
1301 trace_qed_aio_read_data(s, acb, ret, offset, len);
1302
1303 if (ret < 0) {
1304 goto err;
1305 }
1306
1307 qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len);
1308
1309 /* Handle zero cluster and backing file reads */
1310 if (ret == QED_CLUSTER_ZERO) {
1311 qemu_iovec_memset(&acb->cur_qiov, 0, 0, acb->cur_qiov.size);
1312 qed_aio_next_io(acb, 0);
1313 return;
1314 } else if (ret != QED_CLUSTER_FOUND) {
1315 qed_read_backing_file(s, acb->cur_pos, &acb->cur_qiov,
1316 qed_aio_next_io, acb);
1317 return;
1318 }
1319
1320 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
1321 bdrv_aio_readv(bs->file, offset / BDRV_SECTOR_SIZE,
1322 &acb->cur_qiov, acb->cur_qiov.size / BDRV_SECTOR_SIZE,
1323 qed_aio_next_io, acb);
1324 return;
1325
1326 err:
1327 qed_aio_complete(acb, ret);
1328 }
1329
1330 /**
1331 * Begin next I/O or complete the request
1332 */
1333 static void qed_aio_next_io(void *opaque, int ret)
1334 {
1335 QEDAIOCB *acb = opaque;
1336 BDRVQEDState *s = acb_to_s(acb);
1337 QEDFindClusterFunc *io_fn = (acb->flags & QED_AIOCB_WRITE) ?
1338 qed_aio_write_data : qed_aio_read_data;
1339
1340 trace_qed_aio_next_io(s, acb, ret, acb->cur_pos + acb->cur_qiov.size);
1341
1342 /* Handle I/O error */
1343 if (ret) {
1344 qed_aio_complete(acb, ret);
1345 return;
1346 }
1347
1348 acb->qiov_offset += acb->cur_qiov.size;
1349 acb->cur_pos += acb->cur_qiov.size;
1350 qemu_iovec_reset(&acb->cur_qiov);
1351
1352 /* Complete request */
1353 if (acb->cur_pos >= acb->end_pos) {
1354 qed_aio_complete(acb, 0);
1355 return;
1356 }
1357
1358 /* Find next cluster and start I/O */
1359 qed_find_cluster(s, &acb->request,
1360 acb->cur_pos, acb->end_pos - acb->cur_pos,
1361 io_fn, acb);
1362 }
1363
1364 static BlockDriverAIOCB *qed_aio_setup(BlockDriverState *bs,
1365 int64_t sector_num,
1366 QEMUIOVector *qiov, int nb_sectors,
1367 BlockDriverCompletionFunc *cb,
1368 void *opaque, int flags)
1369 {
1370 QEDAIOCB *acb = qemu_aio_get(&qed_aiocb_info, bs, cb, opaque);
1371
1372 trace_qed_aio_setup(bs->opaque, acb, sector_num, nb_sectors,
1373 opaque, flags);
1374
1375 acb->flags = flags;
1376 acb->finished = NULL;
1377 acb->qiov = qiov;
1378 acb->qiov_offset = 0;
1379 acb->cur_pos = (uint64_t)sector_num * BDRV_SECTOR_SIZE;
1380 acb->end_pos = acb->cur_pos + nb_sectors * BDRV_SECTOR_SIZE;
1381 acb->request.l2_table = NULL;
1382 qemu_iovec_init(&acb->cur_qiov, qiov->niov);
1383
1384 /* Start request */
1385 qed_aio_next_io(acb, 0);
1386 return &acb->common;
1387 }
1388
1389 static BlockDriverAIOCB *bdrv_qed_aio_readv(BlockDriverState *bs,
1390 int64_t sector_num,
1391 QEMUIOVector *qiov, int nb_sectors,
1392 BlockDriverCompletionFunc *cb,
1393 void *opaque)
1394 {
1395 return qed_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 0);
1396 }
1397
1398 static BlockDriverAIOCB *bdrv_qed_aio_writev(BlockDriverState *bs,
1399 int64_t sector_num,
1400 QEMUIOVector *qiov, int nb_sectors,
1401 BlockDriverCompletionFunc *cb,
1402 void *opaque)
1403 {
1404 return qed_aio_setup(bs, sector_num, qiov, nb_sectors, cb,
1405 opaque, QED_AIOCB_WRITE);
1406 }
1407
1408 typedef struct {
1409 Coroutine *co;
1410 int ret;
1411 bool done;
1412 } QEDWriteZeroesCB;
1413
1414 static void coroutine_fn qed_co_write_zeroes_cb(void *opaque, int ret)
1415 {
1416 QEDWriteZeroesCB *cb = opaque;
1417
1418 cb->done = true;
1419 cb->ret = ret;
1420 if (cb->co) {
1421 qemu_coroutine_enter(cb->co, NULL);
1422 }
1423 }
1424
1425 static int coroutine_fn bdrv_qed_co_write_zeroes(BlockDriverState *bs,
1426 int64_t sector_num,
1427 int nb_sectors,
1428 BdrvRequestFlags flags)
1429 {
1430 BlockDriverAIOCB *blockacb;
1431 BDRVQEDState *s = bs->opaque;
1432 QEDWriteZeroesCB cb = { .done = false };
1433 QEMUIOVector qiov;
1434 struct iovec iov;
1435
1436 /* Refuse if there are untouched backing file sectors */
1437 if (bs->backing_hd) {
1438 if (qed_offset_into_cluster(s, sector_num * BDRV_SECTOR_SIZE) != 0) {
1439 return -ENOTSUP;
1440 }
1441 if (qed_offset_into_cluster(s, nb_sectors * BDRV_SECTOR_SIZE) != 0) {
1442 return -ENOTSUP;
1443 }
1444 }
1445
1446 /* Zero writes start without an I/O buffer. If a buffer becomes necessary
1447 * then it will be allocated during request processing.
1448 */
1449 iov.iov_base = NULL,
1450 iov.iov_len = nb_sectors * BDRV_SECTOR_SIZE,
1451
1452 qemu_iovec_init_external(&qiov, &iov, 1);
1453 blockacb = qed_aio_setup(bs, sector_num, &qiov, nb_sectors,
1454 qed_co_write_zeroes_cb, &cb,
1455 QED_AIOCB_WRITE | QED_AIOCB_ZERO);
1456 if (!blockacb) {
1457 return -EIO;
1458 }
1459 if (!cb.done) {
1460 cb.co = qemu_coroutine_self();
1461 qemu_coroutine_yield();
1462 }
1463 assert(cb.done);
1464 return cb.ret;
1465 }
1466
1467 static int bdrv_qed_truncate(BlockDriverState *bs, int64_t offset)
1468 {
1469 BDRVQEDState *s = bs->opaque;
1470 uint64_t old_image_size;
1471 int ret;
1472
1473 if (!qed_is_image_size_valid(offset, s->header.cluster_size,
1474 s->header.table_size)) {
1475 return -EINVAL;
1476 }
1477
1478 /* Shrinking is currently not supported */
1479 if ((uint64_t)offset < s->header.image_size) {
1480 return -ENOTSUP;
1481 }
1482
1483 old_image_size = s->header.image_size;
1484 s->header.image_size = offset;
1485 ret = qed_write_header_sync(s);
1486 if (ret < 0) {
1487 s->header.image_size = old_image_size;
1488 }
1489 return ret;
1490 }
1491
1492 static int64_t bdrv_qed_getlength(BlockDriverState *bs)
1493 {
1494 BDRVQEDState *s = bs->opaque;
1495 return s->header.image_size;
1496 }
1497
1498 static int bdrv_qed_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
1499 {
1500 BDRVQEDState *s = bs->opaque;
1501
1502 memset(bdi, 0, sizeof(*bdi));
1503 bdi->cluster_size = s->header.cluster_size;
1504 bdi->is_dirty = s->header.features & QED_F_NEED_CHECK;
1505 bdi->unallocated_blocks_are_zero = true;
1506 bdi->can_write_zeroes_with_unmap = true;
1507 return 0;
1508 }
1509
1510 static int bdrv_qed_change_backing_file(BlockDriverState *bs,
1511 const char *backing_file,
1512 const char *backing_fmt)
1513 {
1514 BDRVQEDState *s = bs->opaque;
1515 QEDHeader new_header, le_header;
1516 void *buffer;
1517 size_t buffer_len, backing_file_len;
1518 int ret;
1519
1520 /* Refuse to set backing filename if unknown compat feature bits are
1521 * active. If the image uses an unknown compat feature then we may not
1522 * know the layout of data following the header structure and cannot safely
1523 * add a new string.
1524 */
1525 if (backing_file && (s->header.compat_features &
1526 ~QED_COMPAT_FEATURE_MASK)) {
1527 return -ENOTSUP;
1528 }
1529
1530 memcpy(&new_header, &s->header, sizeof(new_header));
1531
1532 new_header.features &= ~(QED_F_BACKING_FILE |
1533 QED_F_BACKING_FORMAT_NO_PROBE);
1534
1535 /* Adjust feature flags */
1536 if (backing_file) {
1537 new_header.features |= QED_F_BACKING_FILE;
1538
1539 if (qed_fmt_is_raw(backing_fmt)) {
1540 new_header.features |= QED_F_BACKING_FORMAT_NO_PROBE;
1541 }
1542 }
1543
1544 /* Calculate new header size */
1545 backing_file_len = 0;
1546
1547 if (backing_file) {
1548 backing_file_len = strlen(backing_file);
1549 }
1550
1551 buffer_len = sizeof(new_header);
1552 new_header.backing_filename_offset = buffer_len;
1553 new_header.backing_filename_size = backing_file_len;
1554 buffer_len += backing_file_len;
1555
1556 /* Make sure we can rewrite header without failing */
1557 if (buffer_len > new_header.header_size * new_header.cluster_size) {
1558 return -ENOSPC;
1559 }
1560
1561 /* Prepare new header */
1562 buffer = g_malloc(buffer_len);
1563
1564 qed_header_cpu_to_le(&new_header, &le_header);
1565 memcpy(buffer, &le_header, sizeof(le_header));
1566 buffer_len = sizeof(le_header);
1567
1568 if (backing_file) {
1569 memcpy(buffer + buffer_len, backing_file, backing_file_len);
1570 buffer_len += backing_file_len;
1571 }
1572
1573 /* Write new header */
1574 ret = bdrv_pwrite_sync(bs->file, 0, buffer, buffer_len);
1575 g_free(buffer);
1576 if (ret == 0) {
1577 memcpy(&s->header, &new_header, sizeof(new_header));
1578 }
1579 return ret;
1580 }
1581
1582 static void bdrv_qed_invalidate_cache(BlockDriverState *bs, Error **errp)
1583 {
1584 BDRVQEDState *s = bs->opaque;
1585 Error *local_err = NULL;
1586 int ret;
1587
1588 bdrv_qed_close(bs);
1589
1590 bdrv_invalidate_cache(bs->file, &local_err);
1591 if (local_err) {
1592 error_propagate(errp, local_err);
1593 return;
1594 }
1595
1596 memset(s, 0, sizeof(BDRVQEDState));
1597 ret = bdrv_qed_open(bs, NULL, bs->open_flags, &local_err);
1598 if (local_err) {
1599 error_setg(errp, "Could not reopen qed layer: %s",
1600 error_get_pretty(local_err));
1601 error_free(local_err);
1602 return;
1603 } else if (ret < 0) {
1604 error_setg_errno(errp, -ret, "Could not reopen qed layer");
1605 return;
1606 }
1607 }
1608
1609 static int bdrv_qed_check(BlockDriverState *bs, BdrvCheckResult *result,
1610 BdrvCheckMode fix)
1611 {
1612 BDRVQEDState *s = bs->opaque;
1613
1614 return qed_check(s, result, !!fix);
1615 }
1616
1617 static QemuOptsList qed_create_opts = {
1618 .name = "qed-create-opts",
1619 .head = QTAILQ_HEAD_INITIALIZER(qed_create_opts.head),
1620 .desc = {
1621 {
1622 .name = BLOCK_OPT_SIZE,
1623 .type = QEMU_OPT_SIZE,
1624 .help = "Virtual disk size"
1625 },
1626 {
1627 .name = BLOCK_OPT_BACKING_FILE,
1628 .type = QEMU_OPT_STRING,
1629 .help = "File name of a base image"
1630 },
1631 {
1632 .name = BLOCK_OPT_BACKING_FMT,
1633 .type = QEMU_OPT_STRING,
1634 .help = "Image format of the base image"
1635 },
1636 {
1637 .name = BLOCK_OPT_CLUSTER_SIZE,
1638 .type = QEMU_OPT_SIZE,
1639 .help = "Cluster size (in bytes)",
1640 .def_value_str = stringify(QED_DEFAULT_CLUSTER_SIZE)
1641 },
1642 {
1643 .name = BLOCK_OPT_TABLE_SIZE,
1644 .type = QEMU_OPT_SIZE,
1645 .help = "L1/L2 table size (in clusters)"
1646 },
1647 { /* end of list */ }
1648 }
1649 };
1650
1651 static BlockDriver bdrv_qed = {
1652 .format_name = "qed",
1653 .instance_size = sizeof(BDRVQEDState),
1654 .create_opts = &qed_create_opts,
1655 .supports_backing = true,
1656
1657 .bdrv_probe = bdrv_qed_probe,
1658 .bdrv_rebind = bdrv_qed_rebind,
1659 .bdrv_open = bdrv_qed_open,
1660 .bdrv_close = bdrv_qed_close,
1661 .bdrv_reopen_prepare = bdrv_qed_reopen_prepare,
1662 .bdrv_create = bdrv_qed_create,
1663 .bdrv_has_zero_init = bdrv_has_zero_init_1,
1664 .bdrv_co_get_block_status = bdrv_qed_co_get_block_status,
1665 .bdrv_aio_readv = bdrv_qed_aio_readv,
1666 .bdrv_aio_writev = bdrv_qed_aio_writev,
1667 .bdrv_co_write_zeroes = bdrv_qed_co_write_zeroes,
1668 .bdrv_truncate = bdrv_qed_truncate,
1669 .bdrv_getlength = bdrv_qed_getlength,
1670 .bdrv_get_info = bdrv_qed_get_info,
1671 .bdrv_refresh_limits = bdrv_qed_refresh_limits,
1672 .bdrv_change_backing_file = bdrv_qed_change_backing_file,
1673 .bdrv_invalidate_cache = bdrv_qed_invalidate_cache,
1674 .bdrv_check = bdrv_qed_check,
1675 .bdrv_detach_aio_context = bdrv_qed_detach_aio_context,
1676 .bdrv_attach_aio_context = bdrv_qed_attach_aio_context,
1677 };
1678
1679 static void bdrv_qed_init(void)
1680 {
1681 bdrv_register(&bdrv_qed);
1682 }
1683
1684 block_init(bdrv_qed_init);