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1.1 root 1: /*
2: * QEMU Enhanced Disk Format
3: *
4: * Copyright IBM, Corp. 2010
5: *
6: * Authors:
7: * Stefan Hajnoczi <[email protected]>
8: * Anthony Liguori <[email protected]>
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:
1.1.1.2 ! root 15: #include "qemu-timer.h"
1.1 root 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:
1.1.1.2 ! root 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:
1.1 root 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);
1.1.1.2 ! root 492: if (ret) {
! 493: goto out;
! 494: }
! 495: if (!result.corruptions && !result.check_errors) {
1.1 root 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:
1.1.1.2 ! root 505: s->need_check_timer = qemu_new_timer_ns(vm_clock,
! 506: qed_need_check_timer_cb, s);
! 507:
1.1 root 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:
1.1.1.2 ! root 520: qed_cancel_need_check_timer(s);
! 521: qemu_free_timer(s->need_check_timer);
! 522:
1.1 root 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;
1.1.1.2 ! root 668: cb->is_allocated = (ret == QED_CLUSTER_FOUND || ret == QED_CLUSTER_ZERO);
1.1 root 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(©_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: ©_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(©_cb->qiov, ©_cb->iov, 1);
828:
829: qed_read_backing_file(s, pos, ©_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
1.1.1.2 ! root 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.
1.1 root 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;
1.1.1.2 ! root 851: if (!qed_offset_is_unalloc_cluster(cluster) &&
! 852: !qed_offset_is_zero_cluster(cluster)) {
! 853: cluster += s->header.cluster_size;
! 854: }
1.1 root 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);
1.1.1.2 ! root 904: } else if (s->header.features & QED_F_NEED_CHECK) {
! 905: qed_start_need_check_timer(s);
1.1 root 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;
1.1.1.2 ! root 918: uint64_t l2_offset = l2_table->offset;
1.1 root 919:
920: qed_commit_l2_cache_entry(&s->l2_cache, l2_table);
921:
922: /* This is guaranteed to succeed because we just committed the entry to the
923: * cache.
924: */
1.1.1.2 ! root 925: acb->request.l2_table = qed_find_l2_cache_entry(&s->l2_cache, l2_offset);
1.1 root 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:
1.1.1.2 ! root 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:
1.1 root 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: }
1.1.1.2 ! root 1120: if (acb != QSIMPLEQ_FIRST(&s->allocating_write_reqs) ||
! 1121: s->allocating_write_reqs_plugged) {
1.1 root 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:
1.1.1.2 ! root 1184: case QED_CLUSTER_ZERO:
1.1 root 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:
1.1.1.2 ! root 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) {
1.1 root 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: {
1.1.1.2 ! root 1336: BDRVQEDState *s = bs->opaque;
! 1337: uint64_t old_image_size;
! 1338: int ret;
! 1339:
! 1340: if (!qed_is_image_size_valid(offset, s->header.cluster_size,
! 1341: s->header.table_size)) {
! 1342: return -EINVAL;
! 1343: }
! 1344:
! 1345: /* Shrinking is currently not supported */
! 1346: if ((uint64_t)offset < s->header.image_size) {
! 1347: return -ENOTSUP;
! 1348: }
! 1349:
! 1350: old_image_size = s->header.image_size;
! 1351: s->header.image_size = offset;
! 1352: ret = qed_write_header_sync(s);
! 1353: if (ret < 0) {
! 1354: s->header.image_size = old_image_size;
! 1355: }
! 1356: return ret;
1.1 root 1357: }
1358:
1359: static int64_t bdrv_qed_getlength(BlockDriverState *bs)
1360: {
1361: BDRVQEDState *s = bs->opaque;
1362: return s->header.image_size;
1363: }
1364:
1365: static int bdrv_qed_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
1366: {
1367: BDRVQEDState *s = bs->opaque;
1368:
1369: memset(bdi, 0, sizeof(*bdi));
1370: bdi->cluster_size = s->header.cluster_size;
1371: return 0;
1372: }
1373:
1374: static int bdrv_qed_change_backing_file(BlockDriverState *bs,
1375: const char *backing_file,
1376: const char *backing_fmt)
1377: {
1378: BDRVQEDState *s = bs->opaque;
1379: QEDHeader new_header, le_header;
1380: void *buffer;
1381: size_t buffer_len, backing_file_len;
1382: int ret;
1383:
1384: /* Refuse to set backing filename if unknown compat feature bits are
1385: * active. If the image uses an unknown compat feature then we may not
1386: * know the layout of data following the header structure and cannot safely
1387: * add a new string.
1388: */
1389: if (backing_file && (s->header.compat_features &
1390: ~QED_COMPAT_FEATURE_MASK)) {
1391: return -ENOTSUP;
1392: }
1393:
1394: memcpy(&new_header, &s->header, sizeof(new_header));
1395:
1396: new_header.features &= ~(QED_F_BACKING_FILE |
1397: QED_F_BACKING_FORMAT_NO_PROBE);
1398:
1399: /* Adjust feature flags */
1400: if (backing_file) {
1401: new_header.features |= QED_F_BACKING_FILE;
1402:
1403: if (qed_fmt_is_raw(backing_fmt)) {
1404: new_header.features |= QED_F_BACKING_FORMAT_NO_PROBE;
1405: }
1406: }
1407:
1408: /* Calculate new header size */
1409: backing_file_len = 0;
1410:
1411: if (backing_file) {
1412: backing_file_len = strlen(backing_file);
1413: }
1414:
1415: buffer_len = sizeof(new_header);
1416: new_header.backing_filename_offset = buffer_len;
1417: new_header.backing_filename_size = backing_file_len;
1418: buffer_len += backing_file_len;
1419:
1420: /* Make sure we can rewrite header without failing */
1421: if (buffer_len > new_header.header_size * new_header.cluster_size) {
1422: return -ENOSPC;
1423: }
1424:
1425: /* Prepare new header */
1426: buffer = qemu_malloc(buffer_len);
1427:
1428: qed_header_cpu_to_le(&new_header, &le_header);
1429: memcpy(buffer, &le_header, sizeof(le_header));
1430: buffer_len = sizeof(le_header);
1431:
1432: memcpy(buffer + buffer_len, backing_file, backing_file_len);
1433: buffer_len += backing_file_len;
1434:
1435: /* Write new header */
1436: ret = bdrv_pwrite_sync(bs->file, 0, buffer, buffer_len);
1437: qemu_free(buffer);
1438: if (ret == 0) {
1439: memcpy(&s->header, &new_header, sizeof(new_header));
1440: }
1441: return ret;
1442: }
1443:
1444: static int bdrv_qed_check(BlockDriverState *bs, BdrvCheckResult *result)
1445: {
1446: BDRVQEDState *s = bs->opaque;
1447:
1448: return qed_check(s, result, false);
1449: }
1450:
1451: static QEMUOptionParameter qed_create_options[] = {
1452: {
1453: .name = BLOCK_OPT_SIZE,
1454: .type = OPT_SIZE,
1455: .help = "Virtual disk size (in bytes)"
1456: }, {
1457: .name = BLOCK_OPT_BACKING_FILE,
1458: .type = OPT_STRING,
1459: .help = "File name of a base image"
1460: }, {
1461: .name = BLOCK_OPT_BACKING_FMT,
1462: .type = OPT_STRING,
1463: .help = "Image format of the base image"
1464: }, {
1465: .name = BLOCK_OPT_CLUSTER_SIZE,
1466: .type = OPT_SIZE,
1.1.1.2 ! root 1467: .help = "Cluster size (in bytes)",
! 1468: .value = { .n = QED_DEFAULT_CLUSTER_SIZE },
1.1 root 1469: }, {
1470: .name = BLOCK_OPT_TABLE_SIZE,
1471: .type = OPT_SIZE,
1472: .help = "L1/L2 table size (in clusters)"
1473: },
1474: { /* end of list */ }
1475: };
1476:
1477: static BlockDriver bdrv_qed = {
1478: .format_name = "qed",
1479: .instance_size = sizeof(BDRVQEDState),
1480: .create_options = qed_create_options,
1481:
1482: .bdrv_probe = bdrv_qed_probe,
1483: .bdrv_open = bdrv_qed_open,
1484: .bdrv_close = bdrv_qed_close,
1485: .bdrv_create = bdrv_qed_create,
1486: .bdrv_flush = bdrv_qed_flush,
1487: .bdrv_is_allocated = bdrv_qed_is_allocated,
1488: .bdrv_make_empty = bdrv_qed_make_empty,
1489: .bdrv_aio_readv = bdrv_qed_aio_readv,
1490: .bdrv_aio_writev = bdrv_qed_aio_writev,
1491: .bdrv_aio_flush = bdrv_qed_aio_flush,
1492: .bdrv_truncate = bdrv_qed_truncate,
1493: .bdrv_getlength = bdrv_qed_getlength,
1494: .bdrv_get_info = bdrv_qed_get_info,
1495: .bdrv_change_backing_file = bdrv_qed_change_backing_file,
1496: .bdrv_check = bdrv_qed_check,
1497: };
1498:
1499: static void bdrv_qed_init(void)
1500: {
1501: bdrv_register(&bdrv_qed);
1502: }
1503:
1504: block_init(bdrv_qed_init);
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