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