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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;
1.1.1.3 root 36: int64_t new_l1_table_offset;
1.1 root 37: uint8_t data[12];
38:
39: new_l1_size = s->l1_size;
40: if (min_size <= new_l1_size)
41: return 0;
1.1.1.2 root 42: if (new_l1_size == 0) {
43: new_l1_size = 1;
44: }
1.1 root 45: while (min_size > new_l1_size) {
46: new_l1_size = (new_l1_size * 3 + 1) / 2;
47: }
48: #ifdef DEBUG_ALLOC2
49: printf("grow l1_table from %d to %d\n", s->l1_size, new_l1_size);
50: #endif
51:
52: new_l1_size2 = sizeof(uint64_t) * new_l1_size;
53: new_l1_table = qemu_mallocz(align_offset(new_l1_size2, 512));
54: memcpy(new_l1_table, s->l1_table, s->l1_size * sizeof(uint64_t));
55:
56: /* write new table (align to cluster) */
1.1.1.6 ! root 57: BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_ALLOC_TABLE);
1.1 root 58: new_l1_table_offset = qcow2_alloc_clusters(bs, new_l1_size2);
1.1.1.3 root 59: if (new_l1_table_offset < 0) {
60: qemu_free(new_l1_table);
61: return new_l1_table_offset;
62: }
1.1 root 63:
1.1.1.6 ! root 64: BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_WRITE_TABLE);
1.1 root 65: for(i = 0; i < s->l1_size; i++)
66: new_l1_table[i] = cpu_to_be64(new_l1_table[i]);
1.1.1.6 ! root 67: ret = bdrv_pwrite_sync(bs->file, new_l1_table_offset, new_l1_table, new_l1_size2);
1.1.1.5 root 68: if (ret < 0)
1.1 root 69: goto fail;
70: for(i = 0; i < s->l1_size; i++)
71: new_l1_table[i] = be64_to_cpu(new_l1_table[i]);
72:
73: /* set new table */
1.1.1.6 ! root 74: BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_ACTIVATE_TABLE);
1.1 root 75: cpu_to_be32w((uint32_t*)data, new_l1_size);
76: cpu_to_be64w((uint64_t*)(data + 4), new_l1_table_offset);
1.1.1.6 ! root 77: ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, l1_size), data,sizeof(data));
1.1.1.5 root 78: if (ret < 0) {
1.1 root 79: goto fail;
1.1.1.3 root 80: }
1.1 root 81: qemu_free(s->l1_table);
82: qcow2_free_clusters(bs, s->l1_table_offset, s->l1_size * sizeof(uint64_t));
83: s->l1_table_offset = new_l1_table_offset;
84: s->l1_table = new_l1_table;
85: s->l1_size = new_l1_size;
86: return 0;
87: fail:
1.1.1.3 root 88: qemu_free(new_l1_table);
89: qcow2_free_clusters(bs, new_l1_table_offset, new_l1_size2);
1.1.1.5 root 90: return ret;
1.1 root 91: }
92:
93: void qcow2_l2_cache_reset(BlockDriverState *bs)
94: {
95: BDRVQcowState *s = bs->opaque;
96:
97: memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
98: memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t));
99: memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t));
100: }
101:
102: static inline int l2_cache_new_entry(BlockDriverState *bs)
103: {
104: BDRVQcowState *s = bs->opaque;
105: uint32_t min_count;
106: int min_index, i;
107:
108: /* find a new entry in the least used one */
109: min_index = 0;
110: min_count = 0xffffffff;
111: for(i = 0; i < L2_CACHE_SIZE; i++) {
112: if (s->l2_cache_counts[i] < min_count) {
113: min_count = s->l2_cache_counts[i];
114: min_index = i;
115: }
116: }
117: return min_index;
118: }
119:
120: /*
121: * seek_l2_table
122: *
123: * seek l2_offset in the l2_cache table
124: * if not found, return NULL,
125: * if found,
126: * increments the l2 cache hit count of the entry,
127: * if counter overflow, divide by two all counters
128: * return the pointer to the l2 cache entry
129: *
130: */
131:
132: static uint64_t *seek_l2_table(BDRVQcowState *s, uint64_t l2_offset)
133: {
134: int i, j;
135:
136: for(i = 0; i < L2_CACHE_SIZE; i++) {
137: if (l2_offset == s->l2_cache_offsets[i]) {
138: /* increment the hit count */
139: if (++s->l2_cache_counts[i] == 0xffffffff) {
140: for(j = 0; j < L2_CACHE_SIZE; j++) {
141: s->l2_cache_counts[j] >>= 1;
142: }
143: }
144: return s->l2_cache + (i << s->l2_bits);
145: }
146: }
147: return NULL;
148: }
149:
150: /*
151: * l2_load
152: *
153: * Loads a L2 table into memory. If the table is in the cache, the cache
154: * is used; otherwise the L2 table is loaded from the image file.
155: *
156: * Returns a pointer to the L2 table on success, or NULL if the read from
157: * the image file failed.
158: */
159:
1.1.1.6 ! root 160: static int l2_load(BlockDriverState *bs, uint64_t l2_offset,
! 161: uint64_t **l2_table)
1.1 root 162: {
163: BDRVQcowState *s = bs->opaque;
164: int min_index;
1.1.1.6 ! root 165: int ret;
1.1 root 166:
167: /* seek if the table for the given offset is in the cache */
168:
1.1.1.6 ! root 169: *l2_table = seek_l2_table(s, l2_offset);
! 170: if (*l2_table != NULL) {
! 171: return 0;
! 172: }
1.1 root 173:
174: /* not found: load a new entry in the least used one */
175:
176: min_index = l2_cache_new_entry(bs);
1.1.1.6 ! root 177: *l2_table = s->l2_cache + (min_index << s->l2_bits);
! 178:
! 179: BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD);
! 180: ret = bdrv_pread(bs->file, l2_offset, *l2_table,
! 181: s->l2_size * sizeof(uint64_t));
! 182: if (ret < 0) {
! 183: return ret;
! 184: }
! 185:
1.1 root 186: s->l2_cache_offsets[min_index] = l2_offset;
187: s->l2_cache_counts[min_index] = 1;
188:
1.1.1.6 ! root 189: return 0;
1.1 root 190: }
191:
192: /*
193: * Writes one sector of the L1 table to the disk (can't update single entries
194: * and we really don't want bdrv_pread to perform a read-modify-write)
195: */
196: #define L1_ENTRIES_PER_SECTOR (512 / 8)
1.1.1.6 ! root 197: static int write_l1_entry(BlockDriverState *bs, int l1_index)
1.1 root 198: {
1.1.1.6 ! root 199: BDRVQcowState *s = bs->opaque;
1.1 root 200: uint64_t buf[L1_ENTRIES_PER_SECTOR];
201: int l1_start_index;
1.1.1.5 root 202: int i, ret;
1.1 root 203:
204: l1_start_index = l1_index & ~(L1_ENTRIES_PER_SECTOR - 1);
205: for (i = 0; i < L1_ENTRIES_PER_SECTOR; i++) {
206: buf[i] = cpu_to_be64(s->l1_table[l1_start_index + i]);
207: }
208:
1.1.1.6 ! root 209: BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE);
! 210: ret = bdrv_pwrite_sync(bs->file, s->l1_table_offset + 8 * l1_start_index,
1.1.1.5 root 211: buf, sizeof(buf));
212: if (ret < 0) {
213: return ret;
1.1 root 214: }
215:
216: return 0;
217: }
218:
219: /*
220: * l2_allocate
221: *
222: * Allocate a new l2 entry in the file. If l1_index points to an already
223: * used entry in the L2 table (i.e. we are doing a copy on write for the L2
224: * table) copy the contents of the old L2 table into the newly allocated one.
225: * Otherwise the new table is initialized with zeros.
226: *
227: */
228:
1.1.1.6 ! root 229: static int l2_allocate(BlockDriverState *bs, int l1_index, uint64_t **table)
1.1 root 230: {
231: BDRVQcowState *s = bs->opaque;
232: int min_index;
233: uint64_t old_l2_offset;
1.1.1.3 root 234: uint64_t *l2_table;
235: int64_t l2_offset;
1.1.1.5 root 236: int ret;
1.1 root 237:
238: old_l2_offset = s->l1_table[l1_index];
239:
240: /* allocate a new l2 entry */
241:
242: l2_offset = qcow2_alloc_clusters(bs, s->l2_size * sizeof(uint64_t));
1.1.1.3 root 243: if (l2_offset < 0) {
1.1.1.6 ! root 244: return l2_offset;
1.1.1.3 root 245: }
1.1 root 246:
247: /* allocate a new entry in the l2 cache */
248:
249: min_index = l2_cache_new_entry(bs);
250: l2_table = s->l2_cache + (min_index << s->l2_bits);
251:
252: if (old_l2_offset == 0) {
253: /* if there was no old l2 table, clear the new table */
254: memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
255: } else {
256: /* if there was an old l2 table, read it from the disk */
1.1.1.6 ! root 257: BLKDBG_EVENT(bs->file, BLKDBG_L2_ALLOC_COW_READ);
! 258: ret = bdrv_pread(bs->file, old_l2_offset, l2_table,
! 259: s->l2_size * sizeof(uint64_t));
! 260: if (ret < 0) {
1.1.1.5 root 261: goto fail;
1.1.1.6 ! root 262: }
1.1 root 263: }
264: /* write the l2 table to the file */
1.1.1.6 ! root 265: BLKDBG_EVENT(bs->file, BLKDBG_L2_ALLOC_WRITE);
! 266: ret = bdrv_pwrite_sync(bs->file, l2_offset, l2_table,
1.1.1.5 root 267: s->l2_size * sizeof(uint64_t));
268: if (ret < 0) {
269: goto fail;
270: }
271:
272: /* update the L1 entry */
273: s->l1_table[l1_index] = l2_offset | QCOW_OFLAG_COPIED;
1.1.1.6 ! root 274: ret = write_l1_entry(bs, l1_index);
! 275: if (ret < 0) {
1.1.1.5 root 276: goto fail;
277: }
1.1 root 278:
279: /* update the l2 cache entry */
280:
281: s->l2_cache_offsets[min_index] = l2_offset;
282: s->l2_cache_counts[min_index] = 1;
283:
1.1.1.6 ! root 284: *table = l2_table;
! 285: return 0;
1.1.1.5 root 286:
287: fail:
288: s->l1_table[l1_index] = old_l2_offset;
289: qcow2_l2_cache_reset(bs);
1.1.1.6 ! root 290: return ret;
1.1 root 291: }
292:
293: static int count_contiguous_clusters(uint64_t nb_clusters, int cluster_size,
294: uint64_t *l2_table, uint64_t start, uint64_t mask)
295: {
296: int i;
297: uint64_t offset = be64_to_cpu(l2_table[0]) & ~mask;
298:
299: if (!offset)
300: return 0;
301:
302: for (i = start; i < start + nb_clusters; i++)
1.1.1.2 root 303: if (offset + (uint64_t) i * cluster_size != (be64_to_cpu(l2_table[i]) & ~mask))
1.1 root 304: break;
305:
306: return (i - start);
307: }
308:
309: static int count_contiguous_free_clusters(uint64_t nb_clusters, uint64_t *l2_table)
310: {
311: int i = 0;
312:
313: while(nb_clusters-- && l2_table[i] == 0)
314: i++;
315:
316: return i;
317: }
318:
319: /* The crypt function is compatible with the linux cryptoloop
320: algorithm for < 4 GB images. NOTE: out_buf == in_buf is
321: supported */
322: void qcow2_encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
323: uint8_t *out_buf, const uint8_t *in_buf,
324: int nb_sectors, int enc,
325: const AES_KEY *key)
326: {
327: union {
328: uint64_t ll[2];
329: uint8_t b[16];
330: } ivec;
331: int i;
332:
333: for(i = 0; i < nb_sectors; i++) {
334: ivec.ll[0] = cpu_to_le64(sector_num);
335: ivec.ll[1] = 0;
336: AES_cbc_encrypt(in_buf, out_buf, 512, key,
337: ivec.b, enc);
338: sector_num++;
339: in_buf += 512;
340: out_buf += 512;
341: }
342: }
343:
344:
345: static int qcow_read(BlockDriverState *bs, int64_t sector_num,
346: uint8_t *buf, int nb_sectors)
347: {
348: BDRVQcowState *s = bs->opaque;
349: int ret, index_in_cluster, n, n1;
350: uint64_t cluster_offset;
351:
352: while (nb_sectors > 0) {
353: n = nb_sectors;
1.1.1.6 ! root 354:
! 355: ret = qcow2_get_cluster_offset(bs, sector_num << 9, &n,
! 356: &cluster_offset);
! 357: if (ret < 0) {
! 358: return ret;
! 359: }
! 360:
1.1 root 361: index_in_cluster = sector_num & (s->cluster_sectors - 1);
362: if (!cluster_offset) {
363: if (bs->backing_hd) {
364: /* read from the base image */
365: n1 = qcow2_backing_read1(bs->backing_hd, sector_num, buf, n);
366: if (n1 > 0) {
1.1.1.6 ! root 367: BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING);
1.1 root 368: ret = bdrv_read(bs->backing_hd, sector_num, buf, n1);
369: if (ret < 0)
370: return -1;
371: }
372: } else {
373: memset(buf, 0, 512 * n);
374: }
375: } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
1.1.1.6 ! root 376: if (qcow2_decompress_cluster(bs, cluster_offset) < 0)
1.1 root 377: return -1;
378: memcpy(buf, s->cluster_cache + index_in_cluster * 512, 512 * n);
379: } else {
1.1.1.6 ! root 380: BLKDBG_EVENT(bs->file, BLKDBG_READ);
! 381: ret = bdrv_pread(bs->file, cluster_offset + index_in_cluster * 512, buf, n * 512);
1.1 root 382: if (ret != n * 512)
383: return -1;
384: if (s->crypt_method) {
385: qcow2_encrypt_sectors(s, sector_num, buf, buf, n, 0,
386: &s->aes_decrypt_key);
387: }
388: }
389: nb_sectors -= n;
390: sector_num += n;
391: buf += n * 512;
392: }
393: return 0;
394: }
395:
396: static int copy_sectors(BlockDriverState *bs, uint64_t start_sect,
397: uint64_t cluster_offset, int n_start, int n_end)
398: {
399: BDRVQcowState *s = bs->opaque;
400: int n, ret;
401:
402: n = n_end - n_start;
403: if (n <= 0)
404: return 0;
1.1.1.6 ! root 405: BLKDBG_EVENT(bs->file, BLKDBG_COW_READ);
1.1 root 406: ret = qcow_read(bs, start_sect + n_start, s->cluster_data, n);
407: if (ret < 0)
408: return ret;
409: if (s->crypt_method) {
410: qcow2_encrypt_sectors(s, start_sect + n_start,
411: s->cluster_data,
412: s->cluster_data, n, 1,
413: &s->aes_encrypt_key);
414: }
1.1.1.6 ! root 415: BLKDBG_EVENT(bs->file, BLKDBG_COW_WRITE);
! 416: ret = bdrv_write_sync(bs->file, (cluster_offset >> 9) + n_start,
1.1.1.5 root 417: s->cluster_data, n);
1.1 root 418: if (ret < 0)
419: return ret;
420: return 0;
421: }
422:
423:
424: /*
425: * get_cluster_offset
426: *
1.1.1.6 ! root 427: * For a given offset of the disk image, find the cluster offset in
! 428: * qcow2 file. The offset is stored in *cluster_offset.
1.1 root 429: *
430: * on entry, *num is the number of contiguous clusters we'd like to
431: * access following offset.
432: *
433: * on exit, *num is the number of contiguous clusters we can read.
434: *
1.1.1.6 ! root 435: * Return 0, if the offset is found
! 436: * Return -errno, otherwise.
1.1 root 437: *
438: */
439:
1.1.1.6 ! root 440: int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,
! 441: int *num, uint64_t *cluster_offset)
1.1 root 442: {
443: BDRVQcowState *s = bs->opaque;
1.1.1.2 root 444: unsigned int l1_index, l2_index;
1.1.1.6 ! root 445: uint64_t l2_offset, *l2_table;
1.1 root 446: int l1_bits, c;
1.1.1.2 root 447: unsigned int index_in_cluster, nb_clusters;
448: uint64_t nb_available, nb_needed;
1.1.1.6 ! root 449: int ret;
1.1 root 450:
451: index_in_cluster = (offset >> 9) & (s->cluster_sectors - 1);
452: nb_needed = *num + index_in_cluster;
453:
454: l1_bits = s->l2_bits + s->cluster_bits;
455:
456: /* compute how many bytes there are between the offset and
457: * the end of the l1 entry
458: */
459:
1.1.1.2 root 460: nb_available = (1ULL << l1_bits) - (offset & ((1ULL << l1_bits) - 1));
1.1 root 461:
462: /* compute the number of available sectors */
463:
464: nb_available = (nb_available >> 9) + index_in_cluster;
465:
466: if (nb_needed > nb_available) {
467: nb_needed = nb_available;
468: }
469:
1.1.1.6 ! root 470: *cluster_offset = 0;
1.1 root 471:
472: /* seek the the l2 offset in the l1 table */
473:
474: l1_index = offset >> l1_bits;
475: if (l1_index >= s->l1_size)
476: goto out;
477:
478: l2_offset = s->l1_table[l1_index];
479:
480: /* seek the l2 table of the given l2 offset */
481:
482: if (!l2_offset)
483: goto out;
484:
485: /* load the l2 table in memory */
486:
487: l2_offset &= ~QCOW_OFLAG_COPIED;
1.1.1.6 ! root 488: ret = l2_load(bs, l2_offset, &l2_table);
! 489: if (ret < 0) {
! 490: return ret;
! 491: }
1.1 root 492:
493: /* find the cluster offset for the given disk offset */
494:
495: l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
1.1.1.6 ! root 496: *cluster_offset = be64_to_cpu(l2_table[l2_index]);
1.1 root 497: nb_clusters = size_to_clusters(s, nb_needed << 9);
498:
1.1.1.6 ! root 499: if (!*cluster_offset) {
1.1 root 500: /* how many empty clusters ? */
501: c = count_contiguous_free_clusters(nb_clusters, &l2_table[l2_index]);
502: } else {
503: /* how many allocated clusters ? */
504: c = count_contiguous_clusters(nb_clusters, s->cluster_size,
505: &l2_table[l2_index], 0, QCOW_OFLAG_COPIED);
506: }
507:
508: nb_available = (c * s->cluster_sectors);
509: out:
510: if (nb_available > nb_needed)
511: nb_available = nb_needed;
512:
513: *num = nb_available - index_in_cluster;
514:
1.1.1.6 ! root 515: *cluster_offset &=~QCOW_OFLAG_COPIED;
! 516: return 0;
1.1 root 517: }
518:
519: /*
520: * get_cluster_table
521: *
522: * for a given disk offset, load (and allocate if needed)
523: * the l2 table.
524: *
525: * the l2 table offset in the qcow2 file and the cluster index
526: * in the l2 table are given to the caller.
527: *
1.1.1.3 root 528: * Returns 0 on success, -errno in failure case
1.1 root 529: */
530: static int get_cluster_table(BlockDriverState *bs, uint64_t offset,
531: uint64_t **new_l2_table,
532: uint64_t *new_l2_offset,
533: int *new_l2_index)
534: {
535: BDRVQcowState *s = bs->opaque;
1.1.1.2 root 536: unsigned int l1_index, l2_index;
1.1.1.6 ! root 537: uint64_t l2_offset;
! 538: uint64_t *l2_table = NULL;
1.1.1.2 root 539: int ret;
1.1 root 540:
541: /* seek the the l2 offset in the l1 table */
542:
543: l1_index = offset >> (s->l2_bits + s->cluster_bits);
544: if (l1_index >= s->l1_size) {
545: ret = qcow2_grow_l1_table(bs, l1_index + 1);
1.1.1.3 root 546: if (ret < 0) {
547: return ret;
548: }
1.1 root 549: }
550: l2_offset = s->l1_table[l1_index];
551:
552: /* seek the l2 table of the given l2 offset */
553:
554: if (l2_offset & QCOW_OFLAG_COPIED) {
555: /* load the l2 table in memory */
556: l2_offset &= ~QCOW_OFLAG_COPIED;
1.1.1.6 ! root 557: ret = l2_load(bs, l2_offset, &l2_table);
! 558: if (ret < 0) {
! 559: return ret;
1.1.1.3 root 560: }
1.1 root 561: } else {
562: if (l2_offset)
563: qcow2_free_clusters(bs, l2_offset, s->l2_size * sizeof(uint64_t));
1.1.1.6 ! root 564: ret = l2_allocate(bs, l1_index, &l2_table);
! 565: if (ret < 0) {
! 566: return ret;
1.1.1.3 root 567: }
1.1 root 568: l2_offset = s->l1_table[l1_index] & ~QCOW_OFLAG_COPIED;
569: }
570:
571: /* find the cluster offset for the given disk offset */
572:
573: l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
574:
575: *new_l2_table = l2_table;
576: *new_l2_offset = l2_offset;
577: *new_l2_index = l2_index;
578:
1.1.1.3 root 579: return 0;
1.1 root 580: }
581:
582: /*
583: * alloc_compressed_cluster_offset
584: *
585: * For a given offset of the disk image, return cluster offset in
586: * qcow2 file.
587: *
588: * If the offset is not found, allocate a new compressed cluster.
589: *
590: * Return the cluster offset if successful,
591: * Return 0, otherwise.
592: *
593: */
594:
595: uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
596: uint64_t offset,
597: int compressed_size)
598: {
599: BDRVQcowState *s = bs->opaque;
600: int l2_index, ret;
1.1.1.3 root 601: uint64_t l2_offset, *l2_table;
602: int64_t cluster_offset;
1.1 root 603: int nb_csectors;
604:
605: ret = get_cluster_table(bs, offset, &l2_table, &l2_offset, &l2_index);
1.1.1.3 root 606: if (ret < 0) {
1.1 root 607: return 0;
1.1.1.3 root 608: }
1.1 root 609:
610: cluster_offset = be64_to_cpu(l2_table[l2_index]);
611: if (cluster_offset & QCOW_OFLAG_COPIED)
612: return cluster_offset & ~QCOW_OFLAG_COPIED;
613:
614: if (cluster_offset)
615: qcow2_free_any_clusters(bs, cluster_offset, 1);
616:
617: cluster_offset = qcow2_alloc_bytes(bs, compressed_size);
1.1.1.3 root 618: if (cluster_offset < 0) {
619: return 0;
620: }
621:
1.1 root 622: nb_csectors = ((cluster_offset + compressed_size - 1) >> 9) -
623: (cluster_offset >> 9);
624:
625: cluster_offset |= QCOW_OFLAG_COMPRESSED |
626: ((uint64_t)nb_csectors << s->csize_shift);
627:
628: /* update L2 table */
629:
630: /* compressed clusters never have the copied flag */
631:
1.1.1.6 ! root 632: BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE_COMPRESSED);
1.1 root 633: l2_table[l2_index] = cpu_to_be64(cluster_offset);
1.1.1.6 ! root 634: if (bdrv_pwrite_sync(bs->file,
1.1 root 635: l2_offset + l2_index * sizeof(uint64_t),
636: l2_table + l2_index,
1.1.1.5 root 637: sizeof(uint64_t)) < 0)
1.1 root 638: return 0;
639:
640: return cluster_offset;
641: }
642:
643: /*
644: * Write L2 table updates to disk, writing whole sectors to avoid a
645: * read-modify-write in bdrv_pwrite
646: */
647: #define L2_ENTRIES_PER_SECTOR (512 / 8)
1.1.1.6 ! root 648: static int write_l2_entries(BlockDriverState *bs, uint64_t *l2_table,
1.1 root 649: uint64_t l2_offset, int l2_index, int num)
650: {
651: int l2_start_index = l2_index & ~(L1_ENTRIES_PER_SECTOR - 1);
652: int start_offset = (8 * l2_index) & ~511;
653: int end_offset = (8 * (l2_index + num) + 511) & ~511;
654: size_t len = end_offset - start_offset;
1.1.1.5 root 655: int ret;
1.1 root 656:
1.1.1.6 ! root 657: BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE);
! 658: ret = bdrv_pwrite(bs->file, l2_offset + start_offset,
1.1.1.5 root 659: &l2_table[l2_start_index], len);
660: if (ret < 0) {
661: return ret;
1.1 root 662: }
663:
664: return 0;
665: }
666:
1.1.1.3 root 667: int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m)
1.1 root 668: {
669: BDRVQcowState *s = bs->opaque;
670: int i, j = 0, l2_index, ret;
671: uint64_t *old_cluster, start_sect, l2_offset, *l2_table;
1.1.1.3 root 672: uint64_t cluster_offset = m->cluster_offset;
1.1 root 673:
674: if (m->nb_clusters == 0)
675: return 0;
676:
677: old_cluster = qemu_malloc(m->nb_clusters * sizeof(uint64_t));
678:
679: /* copy content of unmodified sectors */
680: start_sect = (m->offset & ~(s->cluster_size - 1)) >> 9;
681: if (m->n_start) {
682: ret = copy_sectors(bs, start_sect, cluster_offset, 0, m->n_start);
683: if (ret < 0)
684: goto err;
685: }
686:
687: if (m->nb_available & (s->cluster_sectors - 1)) {
688: uint64_t end = m->nb_available & ~(uint64_t)(s->cluster_sectors - 1);
689: ret = copy_sectors(bs, start_sect + end, cluster_offset + (end << 9),
690: m->nb_available - end, s->cluster_sectors);
691: if (ret < 0)
692: goto err;
693: }
694:
695: /* update L2 table */
1.1.1.3 root 696: ret = get_cluster_table(bs, m->offset, &l2_table, &l2_offset, &l2_index);
697: if (ret < 0) {
1.1 root 698: goto err;
1.1.1.3 root 699: }
1.1 root 700:
701: for (i = 0; i < m->nb_clusters; i++) {
702: /* if two concurrent writes happen to the same unallocated cluster
703: * each write allocates separate cluster and writes data concurrently.
704: * The first one to complete updates l2 table with pointer to its
705: * cluster the second one has to do RMW (which is done above by
706: * copy_sectors()), update l2 table with its cluster pointer and free
707: * old cluster. This is what this loop does */
708: if(l2_table[l2_index + i] != 0)
709: old_cluster[j++] = l2_table[l2_index + i];
710:
711: l2_table[l2_index + i] = cpu_to_be64((cluster_offset +
712: (i << s->cluster_bits)) | QCOW_OFLAG_COPIED);
713: }
714:
1.1.1.6 ! root 715: ret = write_l2_entries(bs, l2_table, l2_offset, l2_index, m->nb_clusters);
1.1.1.5 root 716: if (ret < 0) {
717: qcow2_l2_cache_reset(bs);
1.1 root 718: goto err;
719: }
720:
1.1.1.6 ! root 721: /*
! 722: * If this was a COW, we need to decrease the refcount of the old cluster.
! 723: * Also flush bs->file to get the right order for L2 and refcount update.
! 724: */
! 725: if (j != 0) {
! 726: bdrv_flush(bs->file);
! 727: for (i = 0; i < j; i++) {
! 728: qcow2_free_any_clusters(bs,
! 729: be64_to_cpu(old_cluster[i]) & ~QCOW_OFLAG_COPIED, 1);
! 730: }
! 731: }
1.1 root 732:
733: ret = 0;
734: err:
735: qemu_free(old_cluster);
736: return ret;
737: }
738:
739: /*
740: * alloc_cluster_offset
741: *
1.1.1.3 root 742: * For a given offset of the disk image, return cluster offset in qcow2 file.
1.1 root 743: * If the offset is not found, allocate a new cluster.
744: *
1.1.1.3 root 745: * If the cluster was already allocated, m->nb_clusters is set to 0,
746: * m->depends_on is set to NULL and the other fields in m are meaningless.
1.1 root 747: *
1.1.1.3 root 748: * If the cluster is newly allocated, m->nb_clusters is set to the number of
749: * contiguous clusters that have been allocated. This may be 0 if the request
750: * conflict with another write request in flight; in this case, m->depends_on
751: * is set and the remaining fields of m are meaningless.
752: *
753: * If m->nb_clusters is non-zero, the other fields of m are valid and contain
754: * information about the first allocated cluster.
755: *
756: * Return 0 on success and -errno in error cases
1.1 root 757: */
1.1.1.3 root 758: int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,
759: int n_start, int n_end, int *num, QCowL2Meta *m)
1.1 root 760: {
761: BDRVQcowState *s = bs->opaque;
762: int l2_index, ret;
1.1.1.3 root 763: uint64_t l2_offset, *l2_table;
764: int64_t cluster_offset;
1.1.1.2 root 765: unsigned int nb_clusters, i = 0;
1.1 root 766: QCowL2Meta *old_alloc;
767:
768: ret = get_cluster_table(bs, offset, &l2_table, &l2_offset, &l2_index);
1.1.1.3 root 769: if (ret < 0) {
770: return ret;
771: }
1.1 root 772:
773: nb_clusters = size_to_clusters(s, n_end << 9);
774:
775: nb_clusters = MIN(nb_clusters, s->l2_size - l2_index);
776:
777: cluster_offset = be64_to_cpu(l2_table[l2_index]);
778:
779: /* We keep all QCOW_OFLAG_COPIED clusters */
780:
781: if (cluster_offset & QCOW_OFLAG_COPIED) {
782: nb_clusters = count_contiguous_clusters(nb_clusters, s->cluster_size,
783: &l2_table[l2_index], 0, 0);
784:
785: cluster_offset &= ~QCOW_OFLAG_COPIED;
786: m->nb_clusters = 0;
1.1.1.3 root 787: m->depends_on = NULL;
1.1 root 788:
789: goto out;
790: }
791:
792: /* for the moment, multiple compressed clusters are not managed */
793:
794: if (cluster_offset & QCOW_OFLAG_COMPRESSED)
795: nb_clusters = 1;
796:
797: /* how many available clusters ? */
798:
799: while (i < nb_clusters) {
800: i += count_contiguous_clusters(nb_clusters - i, s->cluster_size,
801: &l2_table[l2_index], i, 0);
1.1.1.3 root 802: if ((i >= nb_clusters) || be64_to_cpu(l2_table[l2_index + i])) {
1.1 root 803: break;
1.1.1.3 root 804: }
1.1 root 805:
806: i += count_contiguous_free_clusters(nb_clusters - i,
807: &l2_table[l2_index + i]);
1.1.1.3 root 808: if (i >= nb_clusters) {
809: break;
810: }
1.1 root 811:
812: cluster_offset = be64_to_cpu(l2_table[l2_index + i]);
813:
814: if ((cluster_offset & QCOW_OFLAG_COPIED) ||
815: (cluster_offset & QCOW_OFLAG_COMPRESSED))
816: break;
817: }
1.1.1.3 root 818: assert(i <= nb_clusters);
1.1 root 819: nb_clusters = i;
820:
821: /*
822: * Check if there already is an AIO write request in flight which allocates
823: * the same cluster. In this case we need to wait until the previous
824: * request has completed and updated the L2 table accordingly.
825: */
1.1.1.2 root 826: QLIST_FOREACH(old_alloc, &s->cluster_allocs, next_in_flight) {
1.1 root 827:
828: uint64_t end_offset = offset + nb_clusters * s->cluster_size;
829: uint64_t old_offset = old_alloc->offset;
830: uint64_t old_end_offset = old_alloc->offset +
831: old_alloc->nb_clusters * s->cluster_size;
832:
833: if (end_offset < old_offset || offset > old_end_offset) {
834: /* No intersection */
835: } else {
836: if (offset < old_offset) {
837: /* Stop at the start of a running allocation */
838: nb_clusters = (old_offset - offset) >> s->cluster_bits;
839: } else {
840: nb_clusters = 0;
841: }
842:
843: if (nb_clusters == 0) {
844: /* Set dependency and wait for a callback */
845: m->depends_on = old_alloc;
846: m->nb_clusters = 0;
847: *num = 0;
848: return 0;
849: }
850: }
851: }
852:
853: if (!nb_clusters) {
854: abort();
855: }
856:
1.1.1.2 root 857: QLIST_INSERT_HEAD(&s->cluster_allocs, m, next_in_flight);
1.1 root 858:
859: /* allocate a new cluster */
860:
861: cluster_offset = qcow2_alloc_clusters(bs, nb_clusters * s->cluster_size);
1.1.1.3 root 862: if (cluster_offset < 0) {
1.1.1.4 root 863: QLIST_REMOVE(m, next_in_flight);
1.1.1.3 root 864: return cluster_offset;
865: }
1.1 root 866:
867: /* save info needed for meta data update */
868: m->offset = offset;
869: m->n_start = n_start;
870: m->nb_clusters = nb_clusters;
871:
872: out:
873: m->nb_available = MIN(nb_clusters << (s->cluster_bits - 9), n_end);
1.1.1.3 root 874: m->cluster_offset = cluster_offset;
1.1 root 875:
876: *num = m->nb_available - n_start;
877:
1.1.1.3 root 878: return 0;
1.1 root 879: }
880:
881: static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
882: const uint8_t *buf, int buf_size)
883: {
884: z_stream strm1, *strm = &strm1;
885: int ret, out_len;
886:
887: memset(strm, 0, sizeof(*strm));
888:
889: strm->next_in = (uint8_t *)buf;
890: strm->avail_in = buf_size;
891: strm->next_out = out_buf;
892: strm->avail_out = out_buf_size;
893:
894: ret = inflateInit2(strm, -12);
895: if (ret != Z_OK)
896: return -1;
897: ret = inflate(strm, Z_FINISH);
898: out_len = strm->next_out - out_buf;
899: if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) ||
900: out_len != out_buf_size) {
901: inflateEnd(strm);
902: return -1;
903: }
904: inflateEnd(strm);
905: return 0;
906: }
907:
1.1.1.6 ! root 908: int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset)
1.1 root 909: {
1.1.1.6 ! root 910: BDRVQcowState *s = bs->opaque;
1.1 root 911: int ret, csize, nb_csectors, sector_offset;
912: uint64_t coffset;
913:
914: coffset = cluster_offset & s->cluster_offset_mask;
915: if (s->cluster_cache_offset != coffset) {
916: nb_csectors = ((cluster_offset >> s->csize_shift) & s->csize_mask) + 1;
917: sector_offset = coffset & 511;
918: csize = nb_csectors * 512 - sector_offset;
1.1.1.6 ! root 919: BLKDBG_EVENT(bs->file, BLKDBG_READ_COMPRESSED);
! 920: ret = bdrv_read(bs->file, coffset >> 9, s->cluster_data, nb_csectors);
1.1 root 921: if (ret < 0) {
922: return -1;
923: }
924: if (decompress_buffer(s->cluster_cache, s->cluster_size,
925: s->cluster_data + sector_offset, csize) < 0) {
926: return -1;
927: }
928: s->cluster_cache_offset = coffset;
929: }
930: return 0;
931: }
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