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1.1 root 1: /*
2: * Block driver for the QCOW version 2 format
3: *
4: * Copyright (c) 2004-2006 Fabrice Bellard
5: *
6: * Permission is hereby granted, free of charge, to any person obtaining a copy
7: * of this software and associated documentation files (the "Software"), to deal
8: * in the Software without restriction, including without limitation the rights
9: * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10: * copies of the Software, and to permit persons to whom the Software is
11: * furnished to do so, subject to the following conditions:
12: *
13: * The above copyright notice and this permission notice shall be included in
14: * all copies or substantial portions of the Software.
15: *
16: * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17: * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18: * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19: * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20: * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21: * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22: * THE SOFTWARE.
23: */
24: #include "qemu-common.h"
25: #include "block_int.h"
26: #include "module.h"
27: #include <zlib.h>
28: #include "aes.h"
29: #include "block/qcow2.h"
30:
31: /*
32: Differences with QCOW:
33:
34: - Support for multiple incremental snapshots.
35: - Memory management by reference counts.
36: - Clusters which have a reference count of one have the bit
37: QCOW_OFLAG_COPIED to optimize write performance.
38: - Size of compressed clusters is stored in sectors to reduce bit usage
39: in the cluster offsets.
40: - Support for storing additional data (such as the VM state) in the
41: snapshots.
42: - If a backing store is used, the cluster size is not constrained
43: (could be backported to QCOW).
44: - L2 tables have always a size of one cluster.
45: */
46:
47:
48: typedef struct {
49: uint32_t magic;
50: uint32_t len;
51: } QCowExtension;
52: #define QCOW_EXT_MAGIC_END 0
53: #define QCOW_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA
54:
55:
56:
57: static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename)
58: {
59: const QCowHeader *cow_header = (const void *)buf;
60:
61: if (buf_size >= sizeof(QCowHeader) &&
62: be32_to_cpu(cow_header->magic) == QCOW_MAGIC &&
63: be32_to_cpu(cow_header->version) == QCOW_VERSION)
64: return 100;
65: else
66: return 0;
67: }
68:
69:
70: /*
71: * read qcow2 extension and fill bs
72: * start reading from start_offset
73: * finish reading upon magic of value 0 or when end_offset reached
74: * unknown magic is skipped (future extension this version knows nothing about)
75: * return 0 upon success, non-0 otherwise
76: */
77: static int qcow_read_extensions(BlockDriverState *bs, uint64_t start_offset,
78: uint64_t end_offset)
79: {
80: BDRVQcowState *s = bs->opaque;
81: QCowExtension ext;
82: uint64_t offset;
83:
84: #ifdef DEBUG_EXT
85: printf("qcow_read_extensions: start=%ld end=%ld\n", start_offset, end_offset);
86: #endif
87: offset = start_offset;
88: while (offset < end_offset) {
89:
90: #ifdef DEBUG_EXT
91: /* Sanity check */
92: if (offset > s->cluster_size)
93: printf("qcow_handle_extension: suspicious offset %lu\n", offset);
94:
95: printf("attemting to read extended header in offset %lu\n", offset);
96: #endif
97:
98: if (bdrv_pread(s->hd, offset, &ext, sizeof(ext)) != sizeof(ext)) {
99: fprintf(stderr, "qcow_handle_extension: ERROR: pread fail from offset %llu\n",
100: (unsigned long long)offset);
101: return 1;
102: }
103: be32_to_cpus(&ext.magic);
104: be32_to_cpus(&ext.len);
105: offset += sizeof(ext);
106: #ifdef DEBUG_EXT
107: printf("ext.magic = 0x%x\n", ext.magic);
108: #endif
109: switch (ext.magic) {
110: case QCOW_EXT_MAGIC_END:
111: return 0;
112:
113: case QCOW_EXT_MAGIC_BACKING_FORMAT:
114: if (ext.len >= sizeof(bs->backing_format)) {
115: fprintf(stderr, "ERROR: ext_backing_format: len=%u too large"
116: " (>=%zu)\n",
117: ext.len, sizeof(bs->backing_format));
118: return 2;
119: }
120: if (bdrv_pread(s->hd, offset , bs->backing_format,
121: ext.len) != ext.len)
122: return 3;
123: bs->backing_format[ext.len] = '\0';
124: #ifdef DEBUG_EXT
125: printf("Qcow2: Got format extension %s\n", bs->backing_format);
126: #endif
127: offset += ((ext.len + 7) & ~7);
128: break;
129:
130: default:
131: /* unknown magic -- just skip it */
132: offset += ((ext.len + 7) & ~7);
133: break;
134: }
135: }
136:
137: return 0;
138: }
139:
140:
141: static int qcow_open(BlockDriverState *bs, const char *filename, int flags)
142: {
143: BDRVQcowState *s = bs->opaque;
144: int len, i, shift, ret;
145: QCowHeader header;
146: uint64_t ext_end;
147:
148: ret = bdrv_file_open(&s->hd, filename, flags);
149: if (ret < 0)
150: return ret;
151: if (bdrv_pread(s->hd, 0, &header, sizeof(header)) != sizeof(header))
152: goto fail;
153: be32_to_cpus(&header.magic);
154: be32_to_cpus(&header.version);
155: be64_to_cpus(&header.backing_file_offset);
156: be32_to_cpus(&header.backing_file_size);
157: be64_to_cpus(&header.size);
158: be32_to_cpus(&header.cluster_bits);
159: be32_to_cpus(&header.crypt_method);
160: be64_to_cpus(&header.l1_table_offset);
161: be32_to_cpus(&header.l1_size);
162: be64_to_cpus(&header.refcount_table_offset);
163: be32_to_cpus(&header.refcount_table_clusters);
164: be64_to_cpus(&header.snapshots_offset);
165: be32_to_cpus(&header.nb_snapshots);
166:
167: if (header.magic != QCOW_MAGIC || header.version != QCOW_VERSION)
168: goto fail;
169: if (header.size <= 1 ||
170: header.cluster_bits < MIN_CLUSTER_BITS ||
171: header.cluster_bits > MAX_CLUSTER_BITS)
172: goto fail;
173: if (header.crypt_method > QCOW_CRYPT_AES)
174: goto fail;
175: s->crypt_method_header = header.crypt_method;
176: if (s->crypt_method_header)
177: bs->encrypted = 1;
178: s->cluster_bits = header.cluster_bits;
179: s->cluster_size = 1 << s->cluster_bits;
180: s->cluster_sectors = 1 << (s->cluster_bits - 9);
181: s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */
182: s->l2_size = 1 << s->l2_bits;
183: bs->total_sectors = header.size / 512;
184: s->csize_shift = (62 - (s->cluster_bits - 8));
185: s->csize_mask = (1 << (s->cluster_bits - 8)) - 1;
186: s->cluster_offset_mask = (1LL << s->csize_shift) - 1;
187: s->refcount_table_offset = header.refcount_table_offset;
188: s->refcount_table_size =
189: header.refcount_table_clusters << (s->cluster_bits - 3);
190:
191: s->snapshots_offset = header.snapshots_offset;
192: s->nb_snapshots = header.nb_snapshots;
193:
194: /* read the level 1 table */
195: s->l1_size = header.l1_size;
196: shift = s->cluster_bits + s->l2_bits;
197: s->l1_vm_state_index = (header.size + (1LL << shift) - 1) >> shift;
198: /* the L1 table must contain at least enough entries to put
199: header.size bytes */
200: if (s->l1_size < s->l1_vm_state_index)
201: goto fail;
202: s->l1_table_offset = header.l1_table_offset;
203: s->l1_table = qemu_mallocz(
204: align_offset(s->l1_size * sizeof(uint64_t), 512));
205: if (bdrv_pread(s->hd, s->l1_table_offset, s->l1_table, s->l1_size * sizeof(uint64_t)) !=
206: s->l1_size * sizeof(uint64_t))
207: goto fail;
208: for(i = 0;i < s->l1_size; i++) {
209: be64_to_cpus(&s->l1_table[i]);
210: }
211: /* alloc L2 cache */
212: s->l2_cache = qemu_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
213: s->cluster_cache = qemu_malloc(s->cluster_size);
214: /* one more sector for decompressed data alignment */
215: s->cluster_data = qemu_malloc(QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size
216: + 512);
217: s->cluster_cache_offset = -1;
218:
219: if (qcow2_refcount_init(bs) < 0)
220: goto fail;
221:
222: LIST_INIT(&s->cluster_allocs);
223:
224: /* read qcow2 extensions */
225: if (header.backing_file_offset)
226: ext_end = header.backing_file_offset;
227: else
228: ext_end = s->cluster_size;
229: if (qcow_read_extensions(bs, sizeof(header), ext_end))
230: goto fail;
231:
232: /* read the backing file name */
233: if (header.backing_file_offset != 0) {
234: len = header.backing_file_size;
235: if (len > 1023)
236: len = 1023;
237: if (bdrv_pread(s->hd, header.backing_file_offset, bs->backing_file, len) != len)
238: goto fail;
239: bs->backing_file[len] = '\0';
240: }
241: if (qcow2_read_snapshots(bs) < 0)
242: goto fail;
243:
244: #ifdef DEBUG_ALLOC
245: qcow2_check_refcounts(bs);
246: #endif
247: return 0;
248:
249: fail:
250: qcow2_free_snapshots(bs);
251: qcow2_refcount_close(bs);
252: qemu_free(s->l1_table);
253: qemu_free(s->l2_cache);
254: qemu_free(s->cluster_cache);
255: qemu_free(s->cluster_data);
256: bdrv_delete(s->hd);
257: return -1;
258: }
259:
260: static int qcow_set_key(BlockDriverState *bs, const char *key)
261: {
262: BDRVQcowState *s = bs->opaque;
263: uint8_t keybuf[16];
264: int len, i;
265:
266: memset(keybuf, 0, 16);
267: len = strlen(key);
268: if (len > 16)
269: len = 16;
270: /* XXX: we could compress the chars to 7 bits to increase
271: entropy */
272: for(i = 0;i < len;i++) {
273: keybuf[i] = key[i];
274: }
275: s->crypt_method = s->crypt_method_header;
276:
277: if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0)
278: return -1;
279: if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0)
280: return -1;
281: #if 0
282: /* test */
283: {
284: uint8_t in[16];
285: uint8_t out[16];
286: uint8_t tmp[16];
287: for(i=0;i<16;i++)
288: in[i] = i;
289: AES_encrypt(in, tmp, &s->aes_encrypt_key);
290: AES_decrypt(tmp, out, &s->aes_decrypt_key);
291: for(i = 0; i < 16; i++)
292: printf(" %02x", tmp[i]);
293: printf("\n");
294: for(i = 0; i < 16; i++)
295: printf(" %02x", out[i]);
296: printf("\n");
297: }
298: #endif
299: return 0;
300: }
301:
302: static int qcow_is_allocated(BlockDriverState *bs, int64_t sector_num,
303: int nb_sectors, int *pnum)
304: {
305: uint64_t cluster_offset;
306:
307: *pnum = nb_sectors;
308: cluster_offset = qcow2_get_cluster_offset(bs, sector_num << 9, pnum);
309:
310: return (cluster_offset != 0);
311: }
312:
313: /* handle reading after the end of the backing file */
314: int qcow2_backing_read1(BlockDriverState *bs,
315: int64_t sector_num, uint8_t *buf, int nb_sectors)
316: {
317: int n1;
318: if ((sector_num + nb_sectors) <= bs->total_sectors)
319: return nb_sectors;
320: if (sector_num >= bs->total_sectors)
321: n1 = 0;
322: else
323: n1 = bs->total_sectors - sector_num;
324: memset(buf + n1 * 512, 0, 512 * (nb_sectors - n1));
325: return n1;
326: }
327:
328: typedef struct QCowAIOCB {
329: BlockDriverAIOCB common;
330: int64_t sector_num;
331: QEMUIOVector *qiov;
332: uint8_t *buf;
333: void *orig_buf;
334: int nb_sectors;
335: int n;
336: uint64_t cluster_offset;
337: uint8_t *cluster_data;
338: BlockDriverAIOCB *hd_aiocb;
339: struct iovec hd_iov;
340: QEMUIOVector hd_qiov;
341: QEMUBH *bh;
342: QCowL2Meta l2meta;
343: LIST_ENTRY(QCowAIOCB) next_depend;
344: } QCowAIOCB;
345:
346: static void qcow_aio_cancel(BlockDriverAIOCB *blockacb)
347: {
348: QCowAIOCB *acb = (QCowAIOCB *)blockacb;
349: if (acb->hd_aiocb)
350: bdrv_aio_cancel(acb->hd_aiocb);
351: qemu_aio_release(acb);
352: }
353:
354: static AIOPool qcow_aio_pool = {
355: .aiocb_size = sizeof(QCowAIOCB),
356: .cancel = qcow_aio_cancel,
357: };
358:
359: static void qcow_aio_read_cb(void *opaque, int ret);
360: static void qcow_aio_read_bh(void *opaque)
361: {
362: QCowAIOCB *acb = opaque;
363: qemu_bh_delete(acb->bh);
364: acb->bh = NULL;
365: qcow_aio_read_cb(opaque, 0);
366: }
367:
368: static int qcow_schedule_bh(QEMUBHFunc *cb, QCowAIOCB *acb)
369: {
370: if (acb->bh)
371: return -EIO;
372:
373: acb->bh = qemu_bh_new(cb, acb);
374: if (!acb->bh)
375: return -EIO;
376:
377: qemu_bh_schedule(acb->bh);
378:
379: return 0;
380: }
381:
382: static void qcow_aio_read_cb(void *opaque, int ret)
383: {
384: QCowAIOCB *acb = opaque;
385: BlockDriverState *bs = acb->common.bs;
386: BDRVQcowState *s = bs->opaque;
387: int index_in_cluster, n1;
388:
389: acb->hd_aiocb = NULL;
390: if (ret < 0)
391: goto done;
392:
393: /* post process the read buffer */
394: if (!acb->cluster_offset) {
395: /* nothing to do */
396: } else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) {
397: /* nothing to do */
398: } else {
399: if (s->crypt_method) {
400: qcow2_encrypt_sectors(s, acb->sector_num, acb->buf, acb->buf,
401: acb->n, 0,
402: &s->aes_decrypt_key);
403: }
404: }
405:
406: acb->nb_sectors -= acb->n;
407: acb->sector_num += acb->n;
408: acb->buf += acb->n * 512;
409:
410: if (acb->nb_sectors == 0) {
411: /* request completed */
412: ret = 0;
413: goto done;
414: }
415:
416: /* prepare next AIO request */
417: acb->n = acb->nb_sectors;
418: acb->cluster_offset =
419: qcow2_get_cluster_offset(bs, acb->sector_num << 9, &acb->n);
420: index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
421:
422: if (!acb->cluster_offset) {
423: if (bs->backing_hd) {
424: /* read from the base image */
425: n1 = qcow2_backing_read1(bs->backing_hd, acb->sector_num,
426: acb->buf, acb->n);
427: if (n1 > 0) {
428: acb->hd_iov.iov_base = (void *)acb->buf;
429: acb->hd_iov.iov_len = acb->n * 512;
430: qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
431: acb->hd_aiocb = bdrv_aio_readv(bs->backing_hd, acb->sector_num,
432: &acb->hd_qiov, acb->n,
433: qcow_aio_read_cb, acb);
434: if (acb->hd_aiocb == NULL)
435: goto done;
436: } else {
437: ret = qcow_schedule_bh(qcow_aio_read_bh, acb);
438: if (ret < 0)
439: goto done;
440: }
441: } else {
442: /* Note: in this case, no need to wait */
443: memset(acb->buf, 0, 512 * acb->n);
444: ret = qcow_schedule_bh(qcow_aio_read_bh, acb);
445: if (ret < 0)
446: goto done;
447: }
448: } else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) {
449: /* add AIO support for compressed blocks ? */
450: if (qcow2_decompress_cluster(s, acb->cluster_offset) < 0)
451: goto done;
452: memcpy(acb->buf,
453: s->cluster_cache + index_in_cluster * 512, 512 * acb->n);
454: ret = qcow_schedule_bh(qcow_aio_read_bh, acb);
455: if (ret < 0)
456: goto done;
457: } else {
458: if ((acb->cluster_offset & 511) != 0) {
459: ret = -EIO;
460: goto done;
461: }
462:
463: acb->hd_iov.iov_base = (void *)acb->buf;
464: acb->hd_iov.iov_len = acb->n * 512;
465: qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
466: acb->hd_aiocb = bdrv_aio_readv(s->hd,
467: (acb->cluster_offset >> 9) + index_in_cluster,
468: &acb->hd_qiov, acb->n, qcow_aio_read_cb, acb);
469: if (acb->hd_aiocb == NULL)
470: goto done;
471: }
472:
473: return;
474: done:
475: if (acb->qiov->niov > 1) {
476: qemu_iovec_from_buffer(acb->qiov, acb->orig_buf, acb->qiov->size);
477: qemu_vfree(acb->orig_buf);
478: }
479: acb->common.cb(acb->common.opaque, ret);
480: qemu_aio_release(acb);
481: }
482:
483: static QCowAIOCB *qcow_aio_setup(BlockDriverState *bs,
484: int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
485: BlockDriverCompletionFunc *cb, void *opaque, int is_write)
486: {
487: QCowAIOCB *acb;
488:
489: acb = qemu_aio_get(&qcow_aio_pool, bs, cb, opaque);
490: if (!acb)
491: return NULL;
492: acb->hd_aiocb = NULL;
493: acb->sector_num = sector_num;
494: acb->qiov = qiov;
495: if (qiov->niov > 1) {
496: acb->buf = acb->orig_buf = qemu_blockalign(bs, qiov->size);
497: if (is_write)
498: qemu_iovec_to_buffer(qiov, acb->buf);
499: } else {
500: acb->buf = (uint8_t *)qiov->iov->iov_base;
501: }
502: acb->nb_sectors = nb_sectors;
503: acb->n = 0;
504: acb->cluster_offset = 0;
505: acb->l2meta.nb_clusters = 0;
506: LIST_INIT(&acb->l2meta.dependent_requests);
507: return acb;
508: }
509:
510: static BlockDriverAIOCB *qcow_aio_readv(BlockDriverState *bs,
511: int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
512: BlockDriverCompletionFunc *cb, void *opaque)
513: {
514: QCowAIOCB *acb;
515:
516: acb = qcow_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 0);
517: if (!acb)
518: return NULL;
519:
520: qcow_aio_read_cb(acb, 0);
521: return &acb->common;
522: }
523:
524: static void qcow_aio_write_cb(void *opaque, int ret);
525:
526: static void run_dependent_requests(QCowL2Meta *m)
527: {
528: QCowAIOCB *req;
529: QCowAIOCB *next;
530:
531: /* Take the request off the list of running requests */
532: if (m->nb_clusters != 0) {
533: LIST_REMOVE(m, next_in_flight);
534: }
535:
536: /*
537: * Restart all dependent requests.
538: * Can't use LIST_FOREACH here - the next link might not be the same
539: * any more after the callback (request could depend on a different
540: * request now)
541: */
542: for (req = m->dependent_requests.lh_first; req != NULL; req = next) {
543: next = req->next_depend.le_next;
544: qcow_aio_write_cb(req, 0);
545: }
546:
547: /* Empty the list for the next part of the request */
548: LIST_INIT(&m->dependent_requests);
549: }
550:
551: static void qcow_aio_write_cb(void *opaque, int ret)
552: {
553: QCowAIOCB *acb = opaque;
554: BlockDriverState *bs = acb->common.bs;
555: BDRVQcowState *s = bs->opaque;
556: int index_in_cluster;
557: const uint8_t *src_buf;
558: int n_end;
559:
560: acb->hd_aiocb = NULL;
561:
562: if (ret >= 0) {
563: ret = qcow2_alloc_cluster_link_l2(bs, acb->cluster_offset, &acb->l2meta);
564: }
565:
566: run_dependent_requests(&acb->l2meta);
567:
568: if (ret < 0)
569: goto done;
570:
571: acb->nb_sectors -= acb->n;
572: acb->sector_num += acb->n;
573: acb->buf += acb->n * 512;
574:
575: if (acb->nb_sectors == 0) {
576: /* request completed */
577: ret = 0;
578: goto done;
579: }
580:
581: index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
582: n_end = index_in_cluster + acb->nb_sectors;
583: if (s->crypt_method &&
584: n_end > QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors)
585: n_end = QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors;
586:
587: acb->cluster_offset = qcow2_alloc_cluster_offset(bs, acb->sector_num << 9,
588: index_in_cluster,
589: n_end, &acb->n, &acb->l2meta);
590:
591: /* Need to wait for another request? If so, we are done for now. */
592: if (!acb->cluster_offset && acb->l2meta.depends_on != NULL) {
593: LIST_INSERT_HEAD(&acb->l2meta.depends_on->dependent_requests,
594: acb, next_depend);
595: return;
596: }
597:
598: if (!acb->cluster_offset || (acb->cluster_offset & 511) != 0) {
599: ret = -EIO;
600: goto done;
601: }
602: if (s->crypt_method) {
603: if (!acb->cluster_data) {
604: acb->cluster_data = qemu_mallocz(QCOW_MAX_CRYPT_CLUSTERS *
605: s->cluster_size);
606: }
607: qcow2_encrypt_sectors(s, acb->sector_num, acb->cluster_data, acb->buf,
608: acb->n, 1, &s->aes_encrypt_key);
609: src_buf = acb->cluster_data;
610: } else {
611: src_buf = acb->buf;
612: }
613: acb->hd_iov.iov_base = (void *)src_buf;
614: acb->hd_iov.iov_len = acb->n * 512;
615: qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
616: acb->hd_aiocb = bdrv_aio_writev(s->hd,
617: (acb->cluster_offset >> 9) + index_in_cluster,
618: &acb->hd_qiov, acb->n,
619: qcow_aio_write_cb, acb);
620: if (acb->hd_aiocb == NULL)
621: goto done;
622:
623: return;
624:
625: done:
626: if (acb->qiov->niov > 1)
627: qemu_vfree(acb->orig_buf);
628: acb->common.cb(acb->common.opaque, ret);
629: qemu_aio_release(acb);
630: }
631:
632: static BlockDriverAIOCB *qcow_aio_writev(BlockDriverState *bs,
633: int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
634: BlockDriverCompletionFunc *cb, void *opaque)
635: {
636: BDRVQcowState *s = bs->opaque;
637: QCowAIOCB *acb;
638:
639: s->cluster_cache_offset = -1; /* disable compressed cache */
640:
641: acb = qcow_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 1);
642: if (!acb)
643: return NULL;
644:
645: qcow_aio_write_cb(acb, 0);
646: return &acb->common;
647: }
648:
649: static void qcow_close(BlockDriverState *bs)
650: {
651: BDRVQcowState *s = bs->opaque;
652: qemu_free(s->l1_table);
653: qemu_free(s->l2_cache);
654: qemu_free(s->cluster_cache);
655: qemu_free(s->cluster_data);
656: qcow2_refcount_close(bs);
657: bdrv_delete(s->hd);
658: }
659:
660: static int get_bits_from_size(size_t size)
661: {
662: int res = 0;
663:
664: if (size == 0) {
665: return -1;
666: }
667:
668: while (size != 1) {
669: /* Not a power of two */
670: if (size & 1) {
671: return -1;
672: }
673:
674: size >>= 1;
675: res++;
676: }
677:
678: return res;
679: }
680:
681: static int qcow_create2(const char *filename, int64_t total_size,
682: const char *backing_file, const char *backing_format,
683: int flags, size_t cluster_size)
684: {
685:
686: int fd, header_size, backing_filename_len, l1_size, i, shift, l2_bits;
687: int ref_clusters, backing_format_len = 0;
688: QCowHeader header;
689: uint64_t tmp, offset;
690: QCowCreateState s1, *s = &s1;
691: QCowExtension ext_bf = {0, 0};
692:
693:
694: memset(s, 0, sizeof(*s));
695:
696: fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
697: if (fd < 0)
698: return -1;
699: memset(&header, 0, sizeof(header));
700: header.magic = cpu_to_be32(QCOW_MAGIC);
701: header.version = cpu_to_be32(QCOW_VERSION);
702: header.size = cpu_to_be64(total_size * 512);
703: header_size = sizeof(header);
704: backing_filename_len = 0;
705: if (backing_file) {
706: if (backing_format) {
707: ext_bf.magic = QCOW_EXT_MAGIC_BACKING_FORMAT;
708: backing_format_len = strlen(backing_format);
709: ext_bf.len = (backing_format_len + 7) & ~7;
710: header_size += ((sizeof(ext_bf) + ext_bf.len + 7) & ~7);
711: }
712: header.backing_file_offset = cpu_to_be64(header_size);
713: backing_filename_len = strlen(backing_file);
714: header.backing_file_size = cpu_to_be32(backing_filename_len);
715: header_size += backing_filename_len;
716: }
717:
718: /* Cluster size */
719: s->cluster_bits = get_bits_from_size(cluster_size);
720: if (s->cluster_bits < MIN_CLUSTER_BITS ||
721: s->cluster_bits > MAX_CLUSTER_BITS)
722: {
723: fprintf(stderr, "Cluster size must be a power of two between "
724: "%d and %dk\n",
725: 1 << MIN_CLUSTER_BITS,
726: 1 << (MAX_CLUSTER_BITS - 10));
727: return -EINVAL;
728: }
729: s->cluster_size = 1 << s->cluster_bits;
730:
731: header.cluster_bits = cpu_to_be32(s->cluster_bits);
732: header_size = (header_size + 7) & ~7;
733: if (flags & BLOCK_FLAG_ENCRYPT) {
734: header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
735: } else {
736: header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
737: }
738: l2_bits = s->cluster_bits - 3;
739: shift = s->cluster_bits + l2_bits;
740: l1_size = (((total_size * 512) + (1LL << shift) - 1) >> shift);
741: offset = align_offset(header_size, s->cluster_size);
742: s->l1_table_offset = offset;
743: header.l1_table_offset = cpu_to_be64(s->l1_table_offset);
744: header.l1_size = cpu_to_be32(l1_size);
745: offset += align_offset(l1_size * sizeof(uint64_t), s->cluster_size);
746:
747: s->refcount_table = qemu_mallocz(s->cluster_size);
748:
749: s->refcount_table_offset = offset;
750: header.refcount_table_offset = cpu_to_be64(offset);
751: header.refcount_table_clusters = cpu_to_be32(1);
752: offset += s->cluster_size;
753: s->refcount_block_offset = offset;
754:
755: /* count how many refcount blocks needed */
756: tmp = offset >> s->cluster_bits;
757: ref_clusters = (tmp >> (s->cluster_bits - REFCOUNT_SHIFT)) + 1;
758: for (i=0; i < ref_clusters; i++) {
759: s->refcount_table[i] = cpu_to_be64(offset);
760: offset += s->cluster_size;
761: }
762:
763: s->refcount_block = qemu_mallocz(ref_clusters * s->cluster_size);
764:
765: /* update refcounts */
766: qcow2_create_refcount_update(s, 0, header_size);
767: qcow2_create_refcount_update(s, s->l1_table_offset,
768: l1_size * sizeof(uint64_t));
769: qcow2_create_refcount_update(s, s->refcount_table_offset, s->cluster_size);
770: qcow2_create_refcount_update(s, s->refcount_block_offset,
771: ref_clusters * s->cluster_size);
772:
773: /* write all the data */
774: write(fd, &header, sizeof(header));
775: if (backing_file) {
776: if (backing_format_len) {
777: char zero[16];
778: int d = ext_bf.len - backing_format_len;
779:
780: memset(zero, 0, sizeof(zero));
781: cpu_to_be32s(&ext_bf.magic);
782: cpu_to_be32s(&ext_bf.len);
783: write(fd, &ext_bf, sizeof(ext_bf));
784: write(fd, backing_format, backing_format_len);
785: if (d>0) {
786: write(fd, zero, d);
787: }
788: }
789: write(fd, backing_file, backing_filename_len);
790: }
791: lseek(fd, s->l1_table_offset, SEEK_SET);
792: tmp = 0;
793: for(i = 0;i < l1_size; i++) {
794: write(fd, &tmp, sizeof(tmp));
795: }
796: lseek(fd, s->refcount_table_offset, SEEK_SET);
797: write(fd, s->refcount_table, s->cluster_size);
798:
799: lseek(fd, s->refcount_block_offset, SEEK_SET);
800: write(fd, s->refcount_block, ref_clusters * s->cluster_size);
801:
802: qemu_free(s->refcount_table);
803: qemu_free(s->refcount_block);
804: close(fd);
805: return 0;
806: }
807:
808: static int qcow_create(const char *filename, QEMUOptionParameter *options)
809: {
810: const char *backing_file = NULL;
811: const char *backing_fmt = NULL;
812: uint64_t sectors = 0;
813: int flags = 0;
814: size_t cluster_size = 65536;
815:
816: /* Read out options */
817: while (options && options->name) {
818: if (!strcmp(options->name, BLOCK_OPT_SIZE)) {
819: sectors = options->value.n / 512;
820: } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) {
821: backing_file = options->value.s;
822: } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FMT)) {
823: backing_fmt = options->value.s;
824: } else if (!strcmp(options->name, BLOCK_OPT_ENCRYPT)) {
825: flags |= options->value.n ? BLOCK_FLAG_ENCRYPT : 0;
826: } else if (!strcmp(options->name, BLOCK_OPT_CLUSTER_SIZE)) {
827: if (options->value.n) {
828: cluster_size = options->value.n;
829: }
830: }
831: options++;
832: }
833:
834: return qcow_create2(filename, sectors, backing_file, backing_fmt, flags,
835: cluster_size);
836: }
837:
838: static int qcow_make_empty(BlockDriverState *bs)
839: {
840: #if 0
841: /* XXX: not correct */
842: BDRVQcowState *s = bs->opaque;
843: uint32_t l1_length = s->l1_size * sizeof(uint64_t);
844: int ret;
845:
846: memset(s->l1_table, 0, l1_length);
847: if (bdrv_pwrite(s->hd, s->l1_table_offset, s->l1_table, l1_length) < 0)
848: return -1;
849: ret = bdrv_truncate(s->hd, s->l1_table_offset + l1_length);
850: if (ret < 0)
851: return ret;
852:
853: l2_cache_reset(bs);
854: #endif
855: return 0;
856: }
857:
858: /* XXX: put compressed sectors first, then all the cluster aligned
859: tables to avoid losing bytes in alignment */
860: static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num,
861: const uint8_t *buf, int nb_sectors)
862: {
863: BDRVQcowState *s = bs->opaque;
864: z_stream strm;
865: int ret, out_len;
866: uint8_t *out_buf;
867: uint64_t cluster_offset;
868:
869: if (nb_sectors == 0) {
870: /* align end of file to a sector boundary to ease reading with
871: sector based I/Os */
872: cluster_offset = bdrv_getlength(s->hd);
873: cluster_offset = (cluster_offset + 511) & ~511;
874: bdrv_truncate(s->hd, cluster_offset);
875: return 0;
876: }
877:
878: if (nb_sectors != s->cluster_sectors)
879: return -EINVAL;
880:
881: out_buf = qemu_malloc(s->cluster_size + (s->cluster_size / 1000) + 128);
882:
883: /* best compression, small window, no zlib header */
884: memset(&strm, 0, sizeof(strm));
885: ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
886: Z_DEFLATED, -12,
887: 9, Z_DEFAULT_STRATEGY);
888: if (ret != 0) {
889: qemu_free(out_buf);
890: return -1;
891: }
892:
893: strm.avail_in = s->cluster_size;
894: strm.next_in = (uint8_t *)buf;
895: strm.avail_out = s->cluster_size;
896: strm.next_out = out_buf;
897:
898: ret = deflate(&strm, Z_FINISH);
899: if (ret != Z_STREAM_END && ret != Z_OK) {
900: qemu_free(out_buf);
901: deflateEnd(&strm);
902: return -1;
903: }
904: out_len = strm.next_out - out_buf;
905:
906: deflateEnd(&strm);
907:
908: if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
909: /* could not compress: write normal cluster */
910: bdrv_write(bs, sector_num, buf, s->cluster_sectors);
911: } else {
912: cluster_offset = qcow2_alloc_compressed_cluster_offset(bs,
913: sector_num << 9, out_len);
914: if (!cluster_offset)
915: return -1;
916: cluster_offset &= s->cluster_offset_mask;
917: if (bdrv_pwrite(s->hd, cluster_offset, out_buf, out_len) != out_len) {
918: qemu_free(out_buf);
919: return -1;
920: }
921: }
922:
923: qemu_free(out_buf);
924: return 0;
925: }
926:
927: static void qcow_flush(BlockDriverState *bs)
928: {
929: BDRVQcowState *s = bs->opaque;
930: bdrv_flush(s->hd);
931: }
932:
933: static int64_t qcow_vm_state_offset(BDRVQcowState *s)
934: {
935: return (int64_t)s->l1_vm_state_index << (s->cluster_bits + s->l2_bits);
936: }
937:
938: static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
939: {
940: BDRVQcowState *s = bs->opaque;
941: bdi->cluster_size = s->cluster_size;
942: bdi->vm_state_offset = qcow_vm_state_offset(s);
943: return 0;
944: }
945:
946:
947: static int qcow_check(BlockDriverState *bs)
948: {
949: return qcow2_check_refcounts(bs);
950: }
951:
952: #if 0
953: static void dump_refcounts(BlockDriverState *bs)
954: {
955: BDRVQcowState *s = bs->opaque;
956: int64_t nb_clusters, k, k1, size;
957: int refcount;
958:
959: size = bdrv_getlength(s->hd);
960: nb_clusters = size_to_clusters(s, size);
961: for(k = 0; k < nb_clusters;) {
962: k1 = k;
963: refcount = get_refcount(bs, k);
964: k++;
965: while (k < nb_clusters && get_refcount(bs, k) == refcount)
966: k++;
967: printf("%lld: refcount=%d nb=%lld\n", k, refcount, k - k1);
968: }
969: }
970: #endif
971:
972: static int qcow_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
973: int64_t pos, int size)
974: {
975: BDRVQcowState *s = bs->opaque;
976: int growable = bs->growable;
977:
978: bs->growable = 1;
979: bdrv_pwrite(bs, qcow_vm_state_offset(s) + pos, buf, size);
980: bs->growable = growable;
981:
982: return size;
983: }
984:
985: static int qcow_load_vmstate(BlockDriverState *bs, uint8_t *buf,
986: int64_t pos, int size)
987: {
988: BDRVQcowState *s = bs->opaque;
989: int growable = bs->growable;
990: int ret;
991:
992: bs->growable = 1;
993: ret = bdrv_pread(bs, qcow_vm_state_offset(s) + pos, buf, size);
994: bs->growable = growable;
995:
996: return ret;
997: }
998:
999: static QEMUOptionParameter qcow_create_options[] = {
1000: {
1001: .name = BLOCK_OPT_SIZE,
1002: .type = OPT_SIZE,
1003: .help = "Virtual disk size"
1004: },
1005: {
1006: .name = BLOCK_OPT_BACKING_FILE,
1007: .type = OPT_STRING,
1008: .help = "File name of a base image"
1009: },
1010: {
1011: .name = BLOCK_OPT_BACKING_FMT,
1012: .type = OPT_STRING,
1013: .help = "Image format of the base image"
1014: },
1015: {
1016: .name = BLOCK_OPT_ENCRYPT,
1017: .type = OPT_FLAG,
1018: .help = "Encrypt the image"
1019: },
1020: {
1021: .name = BLOCK_OPT_CLUSTER_SIZE,
1022: .type = OPT_SIZE,
1023: .help = "qcow2 cluster size"
1024: },
1025: { NULL }
1026: };
1027:
1028: static BlockDriver bdrv_qcow2 = {
1029: .format_name = "qcow2",
1030: .instance_size = sizeof(BDRVQcowState),
1031: .bdrv_probe = qcow_probe,
1032: .bdrv_open = qcow_open,
1033: .bdrv_close = qcow_close,
1034: .bdrv_create = qcow_create,
1035: .bdrv_flush = qcow_flush,
1036: .bdrv_is_allocated = qcow_is_allocated,
1037: .bdrv_set_key = qcow_set_key,
1038: .bdrv_make_empty = qcow_make_empty,
1039:
1040: .bdrv_aio_readv = qcow_aio_readv,
1041: .bdrv_aio_writev = qcow_aio_writev,
1042: .bdrv_write_compressed = qcow_write_compressed,
1043:
1044: .bdrv_snapshot_create = qcow2_snapshot_create,
1045: .bdrv_snapshot_goto = qcow2_snapshot_goto,
1046: .bdrv_snapshot_delete = qcow2_snapshot_delete,
1047: .bdrv_snapshot_list = qcow2_snapshot_list,
1048: .bdrv_get_info = qcow_get_info,
1049:
1050: .bdrv_save_vmstate = qcow_save_vmstate,
1051: .bdrv_load_vmstate = qcow_load_vmstate,
1052:
1053: .create_options = qcow_create_options,
1054: .bdrv_check = qcow_check,
1055: };
1056:
1057: static void bdrv_qcow2_init(void)
1058: {
1059: bdrv_register(&bdrv_qcow2);
1060: }
1061:
1062: block_init(bdrv_qcow2_init);
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