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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:
25: #include <zlib.h>
26:
27: #include "qemu-common.h"
28: #include "block_int.h"
29: #include "block/qcow2.h"
30:
31: int qcow2_grow_l1_table(BlockDriverState *bs, int min_size)
32: {
33: BDRVQcowState *s = bs->opaque;
34: int new_l1_size, new_l1_size2, ret, i;
35: uint64_t *new_l1_table;
36: uint64_t new_l1_table_offset;
37: uint8_t data[12];
38:
39: new_l1_size = s->l1_size;
40: if (min_size <= new_l1_size)
41: return 0;
42: while (min_size > new_l1_size) {
43: new_l1_size = (new_l1_size * 3 + 1) / 2;
44: }
45: #ifdef DEBUG_ALLOC2
46: printf("grow l1_table from %d to %d\n", s->l1_size, new_l1_size);
47: #endif
48:
49: new_l1_size2 = sizeof(uint64_t) * new_l1_size;
50: new_l1_table = qemu_mallocz(align_offset(new_l1_size2, 512));
51: memcpy(new_l1_table, s->l1_table, s->l1_size * sizeof(uint64_t));
52:
53: /* write new table (align to cluster) */
54: new_l1_table_offset = qcow2_alloc_clusters(bs, new_l1_size2);
55:
56: for(i = 0; i < s->l1_size; i++)
57: new_l1_table[i] = cpu_to_be64(new_l1_table[i]);
58: ret = bdrv_pwrite(s->hd, new_l1_table_offset, new_l1_table, new_l1_size2);
59: if (ret != new_l1_size2)
60: goto fail;
61: for(i = 0; i < s->l1_size; i++)
62: new_l1_table[i] = be64_to_cpu(new_l1_table[i]);
63:
64: /* set new table */
65: cpu_to_be32w((uint32_t*)data, new_l1_size);
66: cpu_to_be64w((uint64_t*)(data + 4), new_l1_table_offset);
67: if (bdrv_pwrite(s->hd, offsetof(QCowHeader, l1_size), data,
68: sizeof(data)) != sizeof(data))
69: goto fail;
70: qemu_free(s->l1_table);
71: qcow2_free_clusters(bs, s->l1_table_offset, s->l1_size * sizeof(uint64_t));
72: s->l1_table_offset = new_l1_table_offset;
73: s->l1_table = new_l1_table;
74: s->l1_size = new_l1_size;
75: return 0;
76: fail:
77: qemu_free(s->l1_table);
78: return -EIO;
79: }
80:
81: void qcow2_l2_cache_reset(BlockDriverState *bs)
82: {
83: BDRVQcowState *s = bs->opaque;
84:
85: memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
86: memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t));
87: memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t));
88: }
89:
90: static inline int l2_cache_new_entry(BlockDriverState *bs)
91: {
92: BDRVQcowState *s = bs->opaque;
93: uint32_t min_count;
94: int min_index, i;
95:
96: /* find a new entry in the least used one */
97: min_index = 0;
98: min_count = 0xffffffff;
99: for(i = 0; i < L2_CACHE_SIZE; i++) {
100: if (s->l2_cache_counts[i] < min_count) {
101: min_count = s->l2_cache_counts[i];
102: min_index = i;
103: }
104: }
105: return min_index;
106: }
107:
108: /*
109: * seek_l2_table
110: *
111: * seek l2_offset in the l2_cache table
112: * if not found, return NULL,
113: * if found,
114: * increments the l2 cache hit count of the entry,
115: * if counter overflow, divide by two all counters
116: * return the pointer to the l2 cache entry
117: *
118: */
119:
120: static uint64_t *seek_l2_table(BDRVQcowState *s, uint64_t l2_offset)
121: {
122: int i, j;
123:
124: for(i = 0; i < L2_CACHE_SIZE; i++) {
125: if (l2_offset == s->l2_cache_offsets[i]) {
126: /* increment the hit count */
127: if (++s->l2_cache_counts[i] == 0xffffffff) {
128: for(j = 0; j < L2_CACHE_SIZE; j++) {
129: s->l2_cache_counts[j] >>= 1;
130: }
131: }
132: return s->l2_cache + (i << s->l2_bits);
133: }
134: }
135: return NULL;
136: }
137:
138: /*
139: * l2_load
140: *
141: * Loads a L2 table into memory. If the table is in the cache, the cache
142: * is used; otherwise the L2 table is loaded from the image file.
143: *
144: * Returns a pointer to the L2 table on success, or NULL if the read from
145: * the image file failed.
146: */
147:
148: static uint64_t *l2_load(BlockDriverState *bs, uint64_t l2_offset)
149: {
150: BDRVQcowState *s = bs->opaque;
151: int min_index;
152: uint64_t *l2_table;
153:
154: /* seek if the table for the given offset is in the cache */
155:
156: l2_table = seek_l2_table(s, l2_offset);
157: if (l2_table != NULL)
158: return l2_table;
159:
160: /* not found: load a new entry in the least used one */
161:
162: min_index = l2_cache_new_entry(bs);
163: l2_table = s->l2_cache + (min_index << s->l2_bits);
164: if (bdrv_pread(s->hd, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) !=
165: s->l2_size * sizeof(uint64_t))
166: return NULL;
167: s->l2_cache_offsets[min_index] = l2_offset;
168: s->l2_cache_counts[min_index] = 1;
169:
170: return l2_table;
171: }
172:
173: /*
174: * Writes one sector of the L1 table to the disk (can't update single entries
175: * and we really don't want bdrv_pread to perform a read-modify-write)
176: */
177: #define L1_ENTRIES_PER_SECTOR (512 / 8)
178: static int write_l1_entry(BDRVQcowState *s, int l1_index)
179: {
180: uint64_t buf[L1_ENTRIES_PER_SECTOR];
181: int l1_start_index;
182: int i;
183:
184: l1_start_index = l1_index & ~(L1_ENTRIES_PER_SECTOR - 1);
185: for (i = 0; i < L1_ENTRIES_PER_SECTOR; i++) {
186: buf[i] = cpu_to_be64(s->l1_table[l1_start_index + i]);
187: }
188:
189: if (bdrv_pwrite(s->hd, s->l1_table_offset + 8 * l1_start_index,
190: buf, sizeof(buf)) != sizeof(buf))
191: {
192: return -1;
193: }
194:
195: return 0;
196: }
197:
198: /*
199: * l2_allocate
200: *
201: * Allocate a new l2 entry in the file. If l1_index points to an already
202: * used entry in the L2 table (i.e. we are doing a copy on write for the L2
203: * table) copy the contents of the old L2 table into the newly allocated one.
204: * Otherwise the new table is initialized with zeros.
205: *
206: */
207:
208: static uint64_t *l2_allocate(BlockDriverState *bs, int l1_index)
209: {
210: BDRVQcowState *s = bs->opaque;
211: int min_index;
212: uint64_t old_l2_offset;
213: uint64_t *l2_table, l2_offset;
214:
215: old_l2_offset = s->l1_table[l1_index];
216:
217: /* allocate a new l2 entry */
218:
219: l2_offset = qcow2_alloc_clusters(bs, s->l2_size * sizeof(uint64_t));
220:
221: /* update the L1 entry */
222:
223: s->l1_table[l1_index] = l2_offset | QCOW_OFLAG_COPIED;
224: if (write_l1_entry(s, l1_index) < 0) {
225: return NULL;
226: }
227:
228: /* allocate a new entry in the l2 cache */
229:
230: min_index = l2_cache_new_entry(bs);
231: l2_table = s->l2_cache + (min_index << s->l2_bits);
232:
233: if (old_l2_offset == 0) {
234: /* if there was no old l2 table, clear the new table */
235: memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
236: } else {
237: /* if there was an old l2 table, read it from the disk */
238: if (bdrv_pread(s->hd, old_l2_offset,
239: l2_table, s->l2_size * sizeof(uint64_t)) !=
240: s->l2_size * sizeof(uint64_t))
241: return NULL;
242: }
243: /* write the l2 table to the file */
244: if (bdrv_pwrite(s->hd, l2_offset,
245: l2_table, s->l2_size * sizeof(uint64_t)) !=
246: s->l2_size * sizeof(uint64_t))
247: return NULL;
248:
249: /* update the l2 cache entry */
250:
251: s->l2_cache_offsets[min_index] = l2_offset;
252: s->l2_cache_counts[min_index] = 1;
253:
254: return l2_table;
255: }
256:
257: static int count_contiguous_clusters(uint64_t nb_clusters, int cluster_size,
258: uint64_t *l2_table, uint64_t start, uint64_t mask)
259: {
260: int i;
261: uint64_t offset = be64_to_cpu(l2_table[0]) & ~mask;
262:
263: if (!offset)
264: return 0;
265:
266: for (i = start; i < start + nb_clusters; i++)
267: if (offset + i * cluster_size != (be64_to_cpu(l2_table[i]) & ~mask))
268: break;
269:
270: return (i - start);
271: }
272:
273: static int count_contiguous_free_clusters(uint64_t nb_clusters, uint64_t *l2_table)
274: {
275: int i = 0;
276:
277: while(nb_clusters-- && l2_table[i] == 0)
278: i++;
279:
280: return i;
281: }
282:
283: /* The crypt function is compatible with the linux cryptoloop
284: algorithm for < 4 GB images. NOTE: out_buf == in_buf is
285: supported */
286: void qcow2_encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
287: uint8_t *out_buf, const uint8_t *in_buf,
288: int nb_sectors, int enc,
289: const AES_KEY *key)
290: {
291: union {
292: uint64_t ll[2];
293: uint8_t b[16];
294: } ivec;
295: int i;
296:
297: for(i = 0; i < nb_sectors; i++) {
298: ivec.ll[0] = cpu_to_le64(sector_num);
299: ivec.ll[1] = 0;
300: AES_cbc_encrypt(in_buf, out_buf, 512, key,
301: ivec.b, enc);
302: sector_num++;
303: in_buf += 512;
304: out_buf += 512;
305: }
306: }
307:
308:
309: static int qcow_read(BlockDriverState *bs, int64_t sector_num,
310: uint8_t *buf, int nb_sectors)
311: {
312: BDRVQcowState *s = bs->opaque;
313: int ret, index_in_cluster, n, n1;
314: uint64_t cluster_offset;
315:
316: while (nb_sectors > 0) {
317: n = nb_sectors;
318: cluster_offset = qcow2_get_cluster_offset(bs, sector_num << 9, &n);
319: index_in_cluster = sector_num & (s->cluster_sectors - 1);
320: if (!cluster_offset) {
321: if (bs->backing_hd) {
322: /* read from the base image */
323: n1 = qcow2_backing_read1(bs->backing_hd, sector_num, buf, n);
324: if (n1 > 0) {
325: ret = bdrv_read(bs->backing_hd, sector_num, buf, n1);
326: if (ret < 0)
327: return -1;
328: }
329: } else {
330: memset(buf, 0, 512 * n);
331: }
332: } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
333: if (qcow2_decompress_cluster(s, cluster_offset) < 0)
334: return -1;
335: memcpy(buf, s->cluster_cache + index_in_cluster * 512, 512 * n);
336: } else {
337: ret = bdrv_pread(s->hd, cluster_offset + index_in_cluster * 512, buf, n * 512);
338: if (ret != n * 512)
339: return -1;
340: if (s->crypt_method) {
341: qcow2_encrypt_sectors(s, sector_num, buf, buf, n, 0,
342: &s->aes_decrypt_key);
343: }
344: }
345: nb_sectors -= n;
346: sector_num += n;
347: buf += n * 512;
348: }
349: return 0;
350: }
351:
352: static int copy_sectors(BlockDriverState *bs, uint64_t start_sect,
353: uint64_t cluster_offset, int n_start, int n_end)
354: {
355: BDRVQcowState *s = bs->opaque;
356: int n, ret;
357:
358: n = n_end - n_start;
359: if (n <= 0)
360: return 0;
361: ret = qcow_read(bs, start_sect + n_start, s->cluster_data, n);
362: if (ret < 0)
363: return ret;
364: if (s->crypt_method) {
365: qcow2_encrypt_sectors(s, start_sect + n_start,
366: s->cluster_data,
367: s->cluster_data, n, 1,
368: &s->aes_encrypt_key);
369: }
370: ret = bdrv_write(s->hd, (cluster_offset >> 9) + n_start,
371: s->cluster_data, n);
372: if (ret < 0)
373: return ret;
374: return 0;
375: }
376:
377:
378: /*
379: * get_cluster_offset
380: *
381: * For a given offset of the disk image, return cluster offset in
382: * qcow2 file.
383: *
384: * on entry, *num is the number of contiguous clusters we'd like to
385: * access following offset.
386: *
387: * on exit, *num is the number of contiguous clusters we can read.
388: *
389: * Return 1, if the offset is found
390: * Return 0, otherwise.
391: *
392: */
393:
394: uint64_t qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,
395: int *num)
396: {
397: BDRVQcowState *s = bs->opaque;
398: int l1_index, l2_index;
399: uint64_t l2_offset, *l2_table, cluster_offset;
400: int l1_bits, c;
401: int index_in_cluster, nb_available, nb_needed, nb_clusters;
402:
403: index_in_cluster = (offset >> 9) & (s->cluster_sectors - 1);
404: nb_needed = *num + index_in_cluster;
405:
406: l1_bits = s->l2_bits + s->cluster_bits;
407:
408: /* compute how many bytes there are between the offset and
409: * the end of the l1 entry
410: */
411:
412: nb_available = (1 << l1_bits) - (offset & ((1 << l1_bits) - 1));
413:
414: /* compute the number of available sectors */
415:
416: nb_available = (nb_available >> 9) + index_in_cluster;
417:
418: if (nb_needed > nb_available) {
419: nb_needed = nb_available;
420: }
421:
422: cluster_offset = 0;
423:
424: /* seek the the l2 offset in the l1 table */
425:
426: l1_index = offset >> l1_bits;
427: if (l1_index >= s->l1_size)
428: goto out;
429:
430: l2_offset = s->l1_table[l1_index];
431:
432: /* seek the l2 table of the given l2 offset */
433:
434: if (!l2_offset)
435: goto out;
436:
437: /* load the l2 table in memory */
438:
439: l2_offset &= ~QCOW_OFLAG_COPIED;
440: l2_table = l2_load(bs, l2_offset);
441: if (l2_table == NULL)
442: return 0;
443:
444: /* find the cluster offset for the given disk offset */
445:
446: l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
447: cluster_offset = be64_to_cpu(l2_table[l2_index]);
448: nb_clusters = size_to_clusters(s, nb_needed << 9);
449:
450: if (!cluster_offset) {
451: /* how many empty clusters ? */
452: c = count_contiguous_free_clusters(nb_clusters, &l2_table[l2_index]);
453: } else {
454: /* how many allocated clusters ? */
455: c = count_contiguous_clusters(nb_clusters, s->cluster_size,
456: &l2_table[l2_index], 0, QCOW_OFLAG_COPIED);
457: }
458:
459: nb_available = (c * s->cluster_sectors);
460: out:
461: if (nb_available > nb_needed)
462: nb_available = nb_needed;
463:
464: *num = nb_available - index_in_cluster;
465:
466: return cluster_offset & ~QCOW_OFLAG_COPIED;
467: }
468:
469: /*
470: * get_cluster_table
471: *
472: * for a given disk offset, load (and allocate if needed)
473: * the l2 table.
474: *
475: * the l2 table offset in the qcow2 file and the cluster index
476: * in the l2 table are given to the caller.
477: *
478: */
479:
480: static int get_cluster_table(BlockDriverState *bs, uint64_t offset,
481: uint64_t **new_l2_table,
482: uint64_t *new_l2_offset,
483: int *new_l2_index)
484: {
485: BDRVQcowState *s = bs->opaque;
486: int l1_index, l2_index, ret;
487: uint64_t l2_offset, *l2_table;
488:
489: /* seek the the l2 offset in the l1 table */
490:
491: l1_index = offset >> (s->l2_bits + s->cluster_bits);
492: if (l1_index >= s->l1_size) {
493: ret = qcow2_grow_l1_table(bs, l1_index + 1);
494: if (ret < 0)
495: return 0;
496: }
497: l2_offset = s->l1_table[l1_index];
498:
499: /* seek the l2 table of the given l2 offset */
500:
501: if (l2_offset & QCOW_OFLAG_COPIED) {
502: /* load the l2 table in memory */
503: l2_offset &= ~QCOW_OFLAG_COPIED;
504: l2_table = l2_load(bs, l2_offset);
505: if (l2_table == NULL)
506: return 0;
507: } else {
508: if (l2_offset)
509: qcow2_free_clusters(bs, l2_offset, s->l2_size * sizeof(uint64_t));
510: l2_table = l2_allocate(bs, l1_index);
511: if (l2_table == NULL)
512: return 0;
513: l2_offset = s->l1_table[l1_index] & ~QCOW_OFLAG_COPIED;
514: }
515:
516: /* find the cluster offset for the given disk offset */
517:
518: l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
519:
520: *new_l2_table = l2_table;
521: *new_l2_offset = l2_offset;
522: *new_l2_index = l2_index;
523:
524: return 1;
525: }
526:
527: /*
528: * alloc_compressed_cluster_offset
529: *
530: * For a given offset of the disk image, return cluster offset in
531: * qcow2 file.
532: *
533: * If the offset is not found, allocate a new compressed cluster.
534: *
535: * Return the cluster offset if successful,
536: * Return 0, otherwise.
537: *
538: */
539:
540: uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
541: uint64_t offset,
542: int compressed_size)
543: {
544: BDRVQcowState *s = bs->opaque;
545: int l2_index, ret;
546: uint64_t l2_offset, *l2_table, cluster_offset;
547: int nb_csectors;
548:
549: ret = get_cluster_table(bs, offset, &l2_table, &l2_offset, &l2_index);
550: if (ret == 0)
551: return 0;
552:
553: cluster_offset = be64_to_cpu(l2_table[l2_index]);
554: if (cluster_offset & QCOW_OFLAG_COPIED)
555: return cluster_offset & ~QCOW_OFLAG_COPIED;
556:
557: if (cluster_offset)
558: qcow2_free_any_clusters(bs, cluster_offset, 1);
559:
560: cluster_offset = qcow2_alloc_bytes(bs, compressed_size);
561: nb_csectors = ((cluster_offset + compressed_size - 1) >> 9) -
562: (cluster_offset >> 9);
563:
564: cluster_offset |= QCOW_OFLAG_COMPRESSED |
565: ((uint64_t)nb_csectors << s->csize_shift);
566:
567: /* update L2 table */
568:
569: /* compressed clusters never have the copied flag */
570:
571: l2_table[l2_index] = cpu_to_be64(cluster_offset);
572: if (bdrv_pwrite(s->hd,
573: l2_offset + l2_index * sizeof(uint64_t),
574: l2_table + l2_index,
575: sizeof(uint64_t)) != sizeof(uint64_t))
576: return 0;
577:
578: return cluster_offset;
579: }
580:
581: /*
582: * Write L2 table updates to disk, writing whole sectors to avoid a
583: * read-modify-write in bdrv_pwrite
584: */
585: #define L2_ENTRIES_PER_SECTOR (512 / 8)
586: static int write_l2_entries(BDRVQcowState *s, uint64_t *l2_table,
587: uint64_t l2_offset, int l2_index, int num)
588: {
589: int l2_start_index = l2_index & ~(L1_ENTRIES_PER_SECTOR - 1);
590: int start_offset = (8 * l2_index) & ~511;
591: int end_offset = (8 * (l2_index + num) + 511) & ~511;
592: size_t len = end_offset - start_offset;
593:
594: if (bdrv_pwrite(s->hd, l2_offset + start_offset, &l2_table[l2_start_index],
595: len) != len)
596: {
597: return -1;
598: }
599:
600: return 0;
601: }
602:
603: int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, uint64_t cluster_offset,
604: QCowL2Meta *m)
605: {
606: BDRVQcowState *s = bs->opaque;
607: int i, j = 0, l2_index, ret;
608: uint64_t *old_cluster, start_sect, l2_offset, *l2_table;
609:
610: if (m->nb_clusters == 0)
611: return 0;
612:
613: old_cluster = qemu_malloc(m->nb_clusters * sizeof(uint64_t));
614:
615: /* copy content of unmodified sectors */
616: start_sect = (m->offset & ~(s->cluster_size - 1)) >> 9;
617: if (m->n_start) {
618: ret = copy_sectors(bs, start_sect, cluster_offset, 0, m->n_start);
619: if (ret < 0)
620: goto err;
621: }
622:
623: if (m->nb_available & (s->cluster_sectors - 1)) {
624: uint64_t end = m->nb_available & ~(uint64_t)(s->cluster_sectors - 1);
625: ret = copy_sectors(bs, start_sect + end, cluster_offset + (end << 9),
626: m->nb_available - end, s->cluster_sectors);
627: if (ret < 0)
628: goto err;
629: }
630:
631: ret = -EIO;
632: /* update L2 table */
633: if (!get_cluster_table(bs, m->offset, &l2_table, &l2_offset, &l2_index))
634: goto err;
635:
636: for (i = 0; i < m->nb_clusters; i++) {
637: /* if two concurrent writes happen to the same unallocated cluster
638: * each write allocates separate cluster and writes data concurrently.
639: * The first one to complete updates l2 table with pointer to its
640: * cluster the second one has to do RMW (which is done above by
641: * copy_sectors()), update l2 table with its cluster pointer and free
642: * old cluster. This is what this loop does */
643: if(l2_table[l2_index + i] != 0)
644: old_cluster[j++] = l2_table[l2_index + i];
645:
646: l2_table[l2_index + i] = cpu_to_be64((cluster_offset +
647: (i << s->cluster_bits)) | QCOW_OFLAG_COPIED);
648: }
649:
650: if (write_l2_entries(s, l2_table, l2_offset, l2_index, m->nb_clusters) < 0) {
651: ret = -1;
652: goto err;
653: }
654:
655: for (i = 0; i < j; i++)
656: qcow2_free_any_clusters(bs,
657: be64_to_cpu(old_cluster[i]) & ~QCOW_OFLAG_COPIED, 1);
658:
659: ret = 0;
660: err:
661: qemu_free(old_cluster);
662: return ret;
663: }
664:
665: /*
666: * alloc_cluster_offset
667: *
668: * For a given offset of the disk image, return cluster offset in
669: * qcow2 file.
670: *
671: * If the offset is not found, allocate a new cluster.
672: *
673: * Return the cluster offset if successful,
674: * Return 0, otherwise.
675: *
676: */
677:
678: uint64_t qcow2_alloc_cluster_offset(BlockDriverState *bs,
679: uint64_t offset,
680: int n_start, int n_end,
681: int *num, QCowL2Meta *m)
682: {
683: BDRVQcowState *s = bs->opaque;
684: int l2_index, ret;
685: uint64_t l2_offset, *l2_table, cluster_offset;
686: int nb_clusters, i = 0;
687: QCowL2Meta *old_alloc;
688:
689: ret = get_cluster_table(bs, offset, &l2_table, &l2_offset, &l2_index);
690: if (ret == 0)
691: return 0;
692:
693: nb_clusters = size_to_clusters(s, n_end << 9);
694:
695: nb_clusters = MIN(nb_clusters, s->l2_size - l2_index);
696:
697: cluster_offset = be64_to_cpu(l2_table[l2_index]);
698:
699: /* We keep all QCOW_OFLAG_COPIED clusters */
700:
701: if (cluster_offset & QCOW_OFLAG_COPIED) {
702: nb_clusters = count_contiguous_clusters(nb_clusters, s->cluster_size,
703: &l2_table[l2_index], 0, 0);
704:
705: cluster_offset &= ~QCOW_OFLAG_COPIED;
706: m->nb_clusters = 0;
707:
708: goto out;
709: }
710:
711: /* for the moment, multiple compressed clusters are not managed */
712:
713: if (cluster_offset & QCOW_OFLAG_COMPRESSED)
714: nb_clusters = 1;
715:
716: /* how many available clusters ? */
717:
718: while (i < nb_clusters) {
719: i += count_contiguous_clusters(nb_clusters - i, s->cluster_size,
720: &l2_table[l2_index], i, 0);
721:
722: if(be64_to_cpu(l2_table[l2_index + i]))
723: break;
724:
725: i += count_contiguous_free_clusters(nb_clusters - i,
726: &l2_table[l2_index + i]);
727:
728: cluster_offset = be64_to_cpu(l2_table[l2_index + i]);
729:
730: if ((cluster_offset & QCOW_OFLAG_COPIED) ||
731: (cluster_offset & QCOW_OFLAG_COMPRESSED))
732: break;
733: }
734: nb_clusters = i;
735:
736: /*
737: * Check if there already is an AIO write request in flight which allocates
738: * the same cluster. In this case we need to wait until the previous
739: * request has completed and updated the L2 table accordingly.
740: */
741: LIST_FOREACH(old_alloc, &s->cluster_allocs, next_in_flight) {
742:
743: uint64_t end_offset = offset + nb_clusters * s->cluster_size;
744: uint64_t old_offset = old_alloc->offset;
745: uint64_t old_end_offset = old_alloc->offset +
746: old_alloc->nb_clusters * s->cluster_size;
747:
748: if (end_offset < old_offset || offset > old_end_offset) {
749: /* No intersection */
750: } else {
751: if (offset < old_offset) {
752: /* Stop at the start of a running allocation */
753: nb_clusters = (old_offset - offset) >> s->cluster_bits;
754: } else {
755: nb_clusters = 0;
756: }
757:
758: if (nb_clusters == 0) {
759: /* Set dependency and wait for a callback */
760: m->depends_on = old_alloc;
761: m->nb_clusters = 0;
762: *num = 0;
763: return 0;
764: }
765: }
766: }
767:
768: if (!nb_clusters) {
769: abort();
770: }
771:
772: LIST_INSERT_HEAD(&s->cluster_allocs, m, next_in_flight);
773:
774: /* allocate a new cluster */
775:
776: cluster_offset = qcow2_alloc_clusters(bs, nb_clusters * s->cluster_size);
777:
778: /* save info needed for meta data update */
779: m->offset = offset;
780: m->n_start = n_start;
781: m->nb_clusters = nb_clusters;
782:
783: out:
784: m->nb_available = MIN(nb_clusters << (s->cluster_bits - 9), n_end);
785:
786: *num = m->nb_available - n_start;
787:
788: return cluster_offset;
789: }
790:
791: static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
792: const uint8_t *buf, int buf_size)
793: {
794: z_stream strm1, *strm = &strm1;
795: int ret, out_len;
796:
797: memset(strm, 0, sizeof(*strm));
798:
799: strm->next_in = (uint8_t *)buf;
800: strm->avail_in = buf_size;
801: strm->next_out = out_buf;
802: strm->avail_out = out_buf_size;
803:
804: ret = inflateInit2(strm, -12);
805: if (ret != Z_OK)
806: return -1;
807: ret = inflate(strm, Z_FINISH);
808: out_len = strm->next_out - out_buf;
809: if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) ||
810: out_len != out_buf_size) {
811: inflateEnd(strm);
812: return -1;
813: }
814: inflateEnd(strm);
815: return 0;
816: }
817:
818: int qcow2_decompress_cluster(BDRVQcowState *s, uint64_t cluster_offset)
819: {
820: int ret, csize, nb_csectors, sector_offset;
821: uint64_t coffset;
822:
823: coffset = cluster_offset & s->cluster_offset_mask;
824: if (s->cluster_cache_offset != coffset) {
825: nb_csectors = ((cluster_offset >> s->csize_shift) & s->csize_mask) + 1;
826: sector_offset = coffset & 511;
827: csize = nb_csectors * 512 - sector_offset;
828: ret = bdrv_read(s->hd, coffset >> 9, s->cluster_data, nb_csectors);
829: if (ret < 0) {
830: return -1;
831: }
832: if (decompress_buffer(s->cluster_cache, s->cluster_size,
833: s->cluster_data + sector_offset, csize) < 0) {
834: return -1;
835: }
836: s->cluster_cache_offset = coffset;
837: }
838: return 0;
839: }
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