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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"
1.1.1.3 ! root 19: #include "migration.h"
1.1 root 20:
21: static void qed_aio_cancel(BlockDriverAIOCB *blockacb)
22: {
23: QEDAIOCB *acb = (QEDAIOCB *)blockacb;
24: bool finished = false;
25:
26: /* Wait for the request to finish */
27: acb->finished = &finished;
28: while (!finished) {
29: qemu_aio_wait();
30: }
31: }
32:
33: static AIOPool qed_aio_pool = {
34: .aiocb_size = sizeof(QEDAIOCB),
35: .cancel = qed_aio_cancel,
36: };
37:
38: static int bdrv_qed_probe(const uint8_t *buf, int buf_size,
39: const char *filename)
40: {
41: const QEDHeader *header = (const QEDHeader *)buf;
42:
43: if (buf_size < sizeof(*header)) {
44: return 0;
45: }
46: if (le32_to_cpu(header->magic) != QED_MAGIC) {
47: return 0;
48: }
49: return 100;
50: }
51:
52: /**
53: * Check whether an image format is raw
54: *
55: * @fmt: Backing file format, may be NULL
56: */
57: static bool qed_fmt_is_raw(const char *fmt)
58: {
59: return fmt && strcmp(fmt, "raw") == 0;
60: }
61:
62: static void qed_header_le_to_cpu(const QEDHeader *le, QEDHeader *cpu)
63: {
64: cpu->magic = le32_to_cpu(le->magic);
65: cpu->cluster_size = le32_to_cpu(le->cluster_size);
66: cpu->table_size = le32_to_cpu(le->table_size);
67: cpu->header_size = le32_to_cpu(le->header_size);
68: cpu->features = le64_to_cpu(le->features);
69: cpu->compat_features = le64_to_cpu(le->compat_features);
70: cpu->autoclear_features = le64_to_cpu(le->autoclear_features);
71: cpu->l1_table_offset = le64_to_cpu(le->l1_table_offset);
72: cpu->image_size = le64_to_cpu(le->image_size);
73: cpu->backing_filename_offset = le32_to_cpu(le->backing_filename_offset);
74: cpu->backing_filename_size = le32_to_cpu(le->backing_filename_size);
75: }
76:
77: static void qed_header_cpu_to_le(const QEDHeader *cpu, QEDHeader *le)
78: {
79: le->magic = cpu_to_le32(cpu->magic);
80: le->cluster_size = cpu_to_le32(cpu->cluster_size);
81: le->table_size = cpu_to_le32(cpu->table_size);
82: le->header_size = cpu_to_le32(cpu->header_size);
83: le->features = cpu_to_le64(cpu->features);
84: le->compat_features = cpu_to_le64(cpu->compat_features);
85: le->autoclear_features = cpu_to_le64(cpu->autoclear_features);
86: le->l1_table_offset = cpu_to_le64(cpu->l1_table_offset);
87: le->image_size = cpu_to_le64(cpu->image_size);
88: le->backing_filename_offset = cpu_to_le32(cpu->backing_filename_offset);
89: le->backing_filename_size = cpu_to_le32(cpu->backing_filename_size);
90: }
91:
92: static int qed_write_header_sync(BDRVQEDState *s)
93: {
94: QEDHeader le;
95: int ret;
96:
97: qed_header_cpu_to_le(&s->header, &le);
98: ret = bdrv_pwrite(s->bs->file, 0, &le, sizeof(le));
99: if (ret != sizeof(le)) {
100: return ret;
101: }
102: return 0;
103: }
104:
105: typedef struct {
106: GenericCB gencb;
107: BDRVQEDState *s;
108: struct iovec iov;
109: QEMUIOVector qiov;
110: int nsectors;
111: uint8_t *buf;
112: } QEDWriteHeaderCB;
113:
114: static void qed_write_header_cb(void *opaque, int ret)
115: {
116: QEDWriteHeaderCB *write_header_cb = opaque;
117:
118: qemu_vfree(write_header_cb->buf);
119: gencb_complete(write_header_cb, ret);
120: }
121:
122: static void qed_write_header_read_cb(void *opaque, int ret)
123: {
124: QEDWriteHeaderCB *write_header_cb = opaque;
125: BDRVQEDState *s = write_header_cb->s;
126: BlockDriverAIOCB *acb;
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: acb = 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: if (!acb) {
140: qed_write_header_cb(write_header_cb, -EIO);
141: }
142: }
143:
144: /**
145: * Update header in-place (does not rewrite backing filename or other strings)
146: *
147: * This function only updates known header fields in-place and does not affect
148: * extra data after the QED header.
149: */
150: static void qed_write_header(BDRVQEDState *s, BlockDriverCompletionFunc cb,
151: void *opaque)
152: {
153: /* We must write full sectors for O_DIRECT but cannot necessarily generate
154: * the data following the header if an unrecognized compat feature is
155: * active. Therefore, first read the sectors containing the header, update
156: * them, and write back.
157: */
158:
159: BlockDriverAIOCB *acb;
160: int nsectors = (sizeof(QEDHeader) + BDRV_SECTOR_SIZE - 1) /
161: BDRV_SECTOR_SIZE;
162: size_t len = nsectors * BDRV_SECTOR_SIZE;
163: QEDWriteHeaderCB *write_header_cb = gencb_alloc(sizeof(*write_header_cb),
164: cb, opaque);
165:
166: write_header_cb->s = s;
167: write_header_cb->nsectors = nsectors;
168: write_header_cb->buf = qemu_blockalign(s->bs, len);
169: write_header_cb->iov.iov_base = write_header_cb->buf;
170: write_header_cb->iov.iov_len = len;
171: qemu_iovec_init_external(&write_header_cb->qiov, &write_header_cb->iov, 1);
172:
173: acb = bdrv_aio_readv(s->bs->file, 0, &write_header_cb->qiov, nsectors,
174: qed_write_header_read_cb, write_header_cb);
175: if (!acb) {
176: qed_write_header_cb(write_header_cb, -EIO);
177: }
178: }
179:
180: static uint64_t qed_max_image_size(uint32_t cluster_size, uint32_t table_size)
181: {
182: uint64_t table_entries;
183: uint64_t l2_size;
184:
185: table_entries = (table_size * cluster_size) / sizeof(uint64_t);
186: l2_size = table_entries * cluster_size;
187:
188: return l2_size * table_entries;
189: }
190:
191: static bool qed_is_cluster_size_valid(uint32_t cluster_size)
192: {
193: if (cluster_size < QED_MIN_CLUSTER_SIZE ||
194: cluster_size > QED_MAX_CLUSTER_SIZE) {
195: return false;
196: }
197: if (cluster_size & (cluster_size - 1)) {
198: return false; /* not power of 2 */
199: }
200: return true;
201: }
202:
203: static bool qed_is_table_size_valid(uint32_t table_size)
204: {
205: if (table_size < QED_MIN_TABLE_SIZE ||
206: table_size > QED_MAX_TABLE_SIZE) {
207: return false;
208: }
209: if (table_size & (table_size - 1)) {
210: return false; /* not power of 2 */
211: }
212: return true;
213: }
214:
215: static bool qed_is_image_size_valid(uint64_t image_size, uint32_t cluster_size,
216: uint32_t table_size)
217: {
218: if (image_size % BDRV_SECTOR_SIZE != 0) {
219: return false; /* not multiple of sector size */
220: }
221: if (image_size > qed_max_image_size(cluster_size, table_size)) {
222: return false; /* image is too large */
223: }
224: return true;
225: }
226:
227: /**
228: * Read a string of known length from the image file
229: *
230: * @file: Image file
231: * @offset: File offset to start of string, in bytes
232: * @n: String length in bytes
233: * @buf: Destination buffer
234: * @buflen: Destination buffer length in bytes
235: * @ret: 0 on success, -errno on failure
236: *
237: * The string is NUL-terminated.
238: */
239: static int qed_read_string(BlockDriverState *file, uint64_t offset, size_t n,
240: char *buf, size_t buflen)
241: {
242: int ret;
243: if (n >= buflen) {
244: return -EINVAL;
245: }
246: ret = bdrv_pread(file, offset, buf, n);
247: if (ret < 0) {
248: return ret;
249: }
250: buf[n] = '\0';
251: return 0;
252: }
253:
254: /**
255: * Allocate new clusters
256: *
257: * @s: QED state
258: * @n: Number of contiguous clusters to allocate
259: * @ret: Offset of first allocated cluster
260: *
261: * This function only produces the offset where the new clusters should be
262: * written. It updates BDRVQEDState but does not make any changes to the image
263: * file.
264: */
265: static uint64_t qed_alloc_clusters(BDRVQEDState *s, unsigned int n)
266: {
267: uint64_t offset = s->file_size;
268: s->file_size += n * s->header.cluster_size;
269: return offset;
270: }
271:
272: QEDTable *qed_alloc_table(BDRVQEDState *s)
273: {
274: /* Honor O_DIRECT memory alignment requirements */
275: return qemu_blockalign(s->bs,
276: s->header.cluster_size * s->header.table_size);
277: }
278:
279: /**
280: * Allocate a new zeroed L2 table
281: */
282: static CachedL2Table *qed_new_l2_table(BDRVQEDState *s)
283: {
284: CachedL2Table *l2_table = qed_alloc_l2_cache_entry(&s->l2_cache);
285:
286: l2_table->table = qed_alloc_table(s);
287: l2_table->offset = qed_alloc_clusters(s, s->header.table_size);
288:
289: memset(l2_table->table->offsets, 0,
290: s->header.cluster_size * s->header.table_size);
291: return l2_table;
292: }
293:
294: static void qed_aio_next_io(void *opaque, int ret);
295:
1.1.1.2 root 296: static void qed_plug_allocating_write_reqs(BDRVQEDState *s)
297: {
298: assert(!s->allocating_write_reqs_plugged);
299:
300: s->allocating_write_reqs_plugged = true;
301: }
302:
303: static void qed_unplug_allocating_write_reqs(BDRVQEDState *s)
304: {
305: QEDAIOCB *acb;
306:
307: assert(s->allocating_write_reqs_plugged);
308:
309: s->allocating_write_reqs_plugged = false;
310:
311: acb = QSIMPLEQ_FIRST(&s->allocating_write_reqs);
312: if (acb) {
313: qed_aio_next_io(acb, 0);
314: }
315: }
316:
317: static void qed_finish_clear_need_check(void *opaque, int ret)
318: {
319: /* Do nothing */
320: }
321:
322: static void qed_flush_after_clear_need_check(void *opaque, int ret)
323: {
324: BDRVQEDState *s = opaque;
325:
326: bdrv_aio_flush(s->bs, qed_finish_clear_need_check, s);
327:
328: /* No need to wait until flush completes */
329: qed_unplug_allocating_write_reqs(s);
330: }
331:
332: static void qed_clear_need_check(void *opaque, int ret)
333: {
334: BDRVQEDState *s = opaque;
335:
336: if (ret) {
337: qed_unplug_allocating_write_reqs(s);
338: return;
339: }
340:
341: s->header.features &= ~QED_F_NEED_CHECK;
342: qed_write_header(s, qed_flush_after_clear_need_check, s);
343: }
344:
345: static void qed_need_check_timer_cb(void *opaque)
346: {
347: BDRVQEDState *s = opaque;
348:
349: /* The timer should only fire when allocating writes have drained */
350: assert(!QSIMPLEQ_FIRST(&s->allocating_write_reqs));
351:
352: trace_qed_need_check_timer_cb(s);
353:
354: qed_plug_allocating_write_reqs(s);
355:
356: /* Ensure writes are on disk before clearing flag */
357: bdrv_aio_flush(s->bs, qed_clear_need_check, s);
358: }
359:
360: static void qed_start_need_check_timer(BDRVQEDState *s)
361: {
362: trace_qed_start_need_check_timer(s);
363:
364: /* Use vm_clock so we don't alter the image file while suspended for
365: * migration.
366: */
367: qemu_mod_timer(s->need_check_timer, qemu_get_clock_ns(vm_clock) +
368: get_ticks_per_sec() * QED_NEED_CHECK_TIMEOUT);
369: }
370:
371: /* It's okay to call this multiple times or when no timer is started */
372: static void qed_cancel_need_check_timer(BDRVQEDState *s)
373: {
374: trace_qed_cancel_need_check_timer(s);
375: qemu_del_timer(s->need_check_timer);
376: }
377:
1.1 root 378: static int bdrv_qed_open(BlockDriverState *bs, int flags)
379: {
380: BDRVQEDState *s = bs->opaque;
381: QEDHeader le_header;
382: int64_t file_size;
383: int ret;
384:
385: s->bs = bs;
386: QSIMPLEQ_INIT(&s->allocating_write_reqs);
387:
388: ret = bdrv_pread(bs->file, 0, &le_header, sizeof(le_header));
389: if (ret < 0) {
390: return ret;
391: }
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:
1.1.1.3 ! root 508: error_set(&s->migration_blocker,
! 509: QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
! 510: "qed", bs->device_name, "live migration");
! 511: migrate_add_blocker(s->migration_blocker);
! 512:
! 513:
1.1 root 514: out:
515: if (ret) {
516: qed_free_l2_cache(&s->l2_cache);
517: qemu_vfree(s->l1_table);
518: }
519: return ret;
520: }
521:
522: static void bdrv_qed_close(BlockDriverState *bs)
523: {
524: BDRVQEDState *s = bs->opaque;
525:
1.1.1.3 ! root 526: migrate_del_blocker(s->migration_blocker);
! 527: error_free(s->migration_blocker);
! 528:
1.1.1.2 root 529: qed_cancel_need_check_timer(s);
530: qemu_free_timer(s->need_check_timer);
531:
1.1 root 532: /* Ensure writes reach stable storage */
533: bdrv_flush(bs->file);
534:
535: /* Clean shutdown, no check required on next open */
536: if (s->header.features & QED_F_NEED_CHECK) {
537: s->header.features &= ~QED_F_NEED_CHECK;
538: qed_write_header_sync(s);
539: }
540:
541: qed_free_l2_cache(&s->l2_cache);
542: qemu_vfree(s->l1_table);
543: }
544:
545: static int qed_create(const char *filename, uint32_t cluster_size,
546: uint64_t image_size, uint32_t table_size,
547: const char *backing_file, const char *backing_fmt)
548: {
549: QEDHeader header = {
550: .magic = QED_MAGIC,
551: .cluster_size = cluster_size,
552: .table_size = table_size,
553: .header_size = 1,
554: .features = 0,
555: .compat_features = 0,
556: .l1_table_offset = cluster_size,
557: .image_size = image_size,
558: };
559: QEDHeader le_header;
560: uint8_t *l1_table = NULL;
561: size_t l1_size = header.cluster_size * header.table_size;
562: int ret = 0;
563: BlockDriverState *bs = NULL;
564:
565: ret = bdrv_create_file(filename, NULL);
566: if (ret < 0) {
567: return ret;
568: }
569:
570: ret = bdrv_file_open(&bs, filename, BDRV_O_RDWR | BDRV_O_CACHE_WB);
571: if (ret < 0) {
572: return ret;
573: }
574:
575: /* File must start empty and grow, check truncate is supported */
576: ret = bdrv_truncate(bs, 0);
577: if (ret < 0) {
578: goto out;
579: }
580:
581: if (backing_file) {
582: header.features |= QED_F_BACKING_FILE;
583: header.backing_filename_offset = sizeof(le_header);
584: header.backing_filename_size = strlen(backing_file);
585:
586: if (qed_fmt_is_raw(backing_fmt)) {
587: header.features |= QED_F_BACKING_FORMAT_NO_PROBE;
588: }
589: }
590:
591: qed_header_cpu_to_le(&header, &le_header);
592: ret = bdrv_pwrite(bs, 0, &le_header, sizeof(le_header));
593: if (ret < 0) {
594: goto out;
595: }
596: ret = bdrv_pwrite(bs, sizeof(le_header), backing_file,
597: header.backing_filename_size);
598: if (ret < 0) {
599: goto out;
600: }
601:
1.1.1.3 ! root 602: l1_table = g_malloc0(l1_size);
1.1 root 603: ret = bdrv_pwrite(bs, header.l1_table_offset, l1_table, l1_size);
604: if (ret < 0) {
605: goto out;
606: }
607:
608: ret = 0; /* success */
609: out:
1.1.1.3 ! root 610: g_free(l1_table);
1.1 root 611: bdrv_delete(bs);
612: return ret;
613: }
614:
615: static int bdrv_qed_create(const char *filename, QEMUOptionParameter *options)
616: {
617: uint64_t image_size = 0;
618: uint32_t cluster_size = QED_DEFAULT_CLUSTER_SIZE;
619: uint32_t table_size = QED_DEFAULT_TABLE_SIZE;
620: const char *backing_file = NULL;
621: const char *backing_fmt = NULL;
622:
623: while (options && options->name) {
624: if (!strcmp(options->name, BLOCK_OPT_SIZE)) {
625: image_size = options->value.n;
626: } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) {
627: backing_file = options->value.s;
628: } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FMT)) {
629: backing_fmt = options->value.s;
630: } else if (!strcmp(options->name, BLOCK_OPT_CLUSTER_SIZE)) {
631: if (options->value.n) {
632: cluster_size = options->value.n;
633: }
634: } else if (!strcmp(options->name, BLOCK_OPT_TABLE_SIZE)) {
635: if (options->value.n) {
636: table_size = options->value.n;
637: }
638: }
639: options++;
640: }
641:
642: if (!qed_is_cluster_size_valid(cluster_size)) {
643: fprintf(stderr, "QED cluster size must be within range [%u, %u] and power of 2\n",
644: QED_MIN_CLUSTER_SIZE, QED_MAX_CLUSTER_SIZE);
645: return -EINVAL;
646: }
647: if (!qed_is_table_size_valid(table_size)) {
648: fprintf(stderr, "QED table size must be within range [%u, %u] and power of 2\n",
649: QED_MIN_TABLE_SIZE, QED_MAX_TABLE_SIZE);
650: return -EINVAL;
651: }
652: if (!qed_is_image_size_valid(image_size, cluster_size, table_size)) {
653: fprintf(stderr, "QED image size must be a non-zero multiple of "
654: "cluster size and less than %" PRIu64 " bytes\n",
655: qed_max_image_size(cluster_size, table_size));
656: return -EINVAL;
657: }
658:
659: return qed_create(filename, cluster_size, image_size, table_size,
660: backing_file, backing_fmt);
661: }
662:
663: typedef struct {
664: int is_allocated;
665: int *pnum;
666: } QEDIsAllocatedCB;
667:
668: static void qed_is_allocated_cb(void *opaque, int ret, uint64_t offset, size_t len)
669: {
670: QEDIsAllocatedCB *cb = opaque;
671: *cb->pnum = len / BDRV_SECTOR_SIZE;
1.1.1.2 root 672: cb->is_allocated = (ret == QED_CLUSTER_FOUND || ret == QED_CLUSTER_ZERO);
1.1 root 673: }
674:
675: static int bdrv_qed_is_allocated(BlockDriverState *bs, int64_t sector_num,
676: int nb_sectors, int *pnum)
677: {
678: BDRVQEDState *s = bs->opaque;
679: uint64_t pos = (uint64_t)sector_num * BDRV_SECTOR_SIZE;
680: size_t len = (size_t)nb_sectors * BDRV_SECTOR_SIZE;
681: QEDIsAllocatedCB cb = {
682: .is_allocated = -1,
683: .pnum = pnum,
684: };
685: QEDRequest request = { .l2_table = NULL };
686:
687: qed_find_cluster(s, &request, pos, len, qed_is_allocated_cb, &cb);
688:
689: while (cb.is_allocated == -1) {
690: qemu_aio_wait();
691: }
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 */
1.1.1.3 ! root 1426: buffer = g_malloc(buffer_len);
1.1 root 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:
1.1.1.3 ! root 1432: if (backing_file) {
! 1433: memcpy(buffer + buffer_len, backing_file, backing_file_len);
! 1434: buffer_len += backing_file_len;
! 1435: }
1.1 root 1436:
1437: /* Write new header */
1438: ret = bdrv_pwrite_sync(bs->file, 0, buffer, buffer_len);
1.1.1.3 ! root 1439: g_free(buffer);
1.1 root 1440: if (ret == 0) {
1441: memcpy(&s->header, &new_header, sizeof(new_header));
1442: }
1443: return ret;
1444: }
1445:
1446: static int bdrv_qed_check(BlockDriverState *bs, BdrvCheckResult *result)
1447: {
1448: BDRVQEDState *s = bs->opaque;
1449:
1450: return qed_check(s, result, false);
1451: }
1452:
1453: static QEMUOptionParameter qed_create_options[] = {
1454: {
1455: .name = BLOCK_OPT_SIZE,
1456: .type = OPT_SIZE,
1457: .help = "Virtual disk size (in bytes)"
1458: }, {
1459: .name = BLOCK_OPT_BACKING_FILE,
1460: .type = OPT_STRING,
1461: .help = "File name of a base image"
1462: }, {
1463: .name = BLOCK_OPT_BACKING_FMT,
1464: .type = OPT_STRING,
1465: .help = "Image format of the base image"
1466: }, {
1467: .name = BLOCK_OPT_CLUSTER_SIZE,
1468: .type = OPT_SIZE,
1.1.1.2 root 1469: .help = "Cluster size (in bytes)",
1470: .value = { .n = QED_DEFAULT_CLUSTER_SIZE },
1.1 root 1471: }, {
1472: .name = BLOCK_OPT_TABLE_SIZE,
1473: .type = OPT_SIZE,
1474: .help = "L1/L2 table size (in clusters)"
1475: },
1476: { /* end of list */ }
1477: };
1478:
1479: static BlockDriver bdrv_qed = {
1480: .format_name = "qed",
1481: .instance_size = sizeof(BDRVQEDState),
1482: .create_options = qed_create_options,
1483:
1484: .bdrv_probe = bdrv_qed_probe,
1485: .bdrv_open = bdrv_qed_open,
1486: .bdrv_close = bdrv_qed_close,
1487: .bdrv_create = bdrv_qed_create,
1488: .bdrv_is_allocated = bdrv_qed_is_allocated,
1489: .bdrv_make_empty = bdrv_qed_make_empty,
1490: .bdrv_aio_readv = bdrv_qed_aio_readv,
1491: .bdrv_aio_writev = bdrv_qed_aio_writev,
1492: .bdrv_aio_flush = bdrv_qed_aio_flush,
1493: .bdrv_truncate = bdrv_qed_truncate,
1494: .bdrv_getlength = bdrv_qed_getlength,
1495: .bdrv_get_info = bdrv_qed_get_info,
1496: .bdrv_change_backing_file = bdrv_qed_change_backing_file,
1497: .bdrv_check = bdrv_qed_check,
1498: };
1499:
1500: static void bdrv_qed_init(void)
1501: {
1502: bdrv_register(&bdrv_qed);
1503: }
1504:
1505: block_init(bdrv_qed_init);
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