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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:
1.1.1.7 ! root 31: int qcow2_grow_l1_table(BlockDriverState *bs, int min_size, bool exact_size)
1.1 root 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:
1.1.1.7 ! root 39: if (min_size <= s->l1_size)
1.1 root 40: return 0;
1.1.1.7 ! root 41:
! 42: if (exact_size) {
! 43: new_l1_size = min_size;
! 44: } else {
! 45: /* Bump size up to reduce the number of times we have to grow */
! 46: new_l1_size = s->l1_size;
! 47: if (new_l1_size == 0) {
! 48: new_l1_size = 1;
! 49: }
! 50: while (min_size > new_l1_size) {
! 51: new_l1_size = (new_l1_size * 3 + 1) / 2;
! 52: }
1.1 root 53: }
1.1.1.7 ! root 54:
1.1 root 55: #ifdef DEBUG_ALLOC2
56: printf("grow l1_table from %d to %d\n", s->l1_size, new_l1_size);
57: #endif
58:
59: new_l1_size2 = sizeof(uint64_t) * new_l1_size;
60: new_l1_table = qemu_mallocz(align_offset(new_l1_size2, 512));
61: memcpy(new_l1_table, s->l1_table, s->l1_size * sizeof(uint64_t));
62:
63: /* write new table (align to cluster) */
1.1.1.6 root 64: BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_ALLOC_TABLE);
1.1 root 65: new_l1_table_offset = qcow2_alloc_clusters(bs, new_l1_size2);
1.1.1.3 root 66: if (new_l1_table_offset < 0) {
67: qemu_free(new_l1_table);
68: return new_l1_table_offset;
69: }
1.1 root 70:
1.1.1.7 ! root 71: ret = qcow2_cache_flush(bs, s->refcount_block_cache);
! 72: if (ret < 0) {
! 73: return ret;
! 74: }
! 75:
1.1.1.6 root 76: BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_WRITE_TABLE);
1.1 root 77: for(i = 0; i < s->l1_size; i++)
78: new_l1_table[i] = cpu_to_be64(new_l1_table[i]);
1.1.1.6 root 79: ret = bdrv_pwrite_sync(bs->file, new_l1_table_offset, new_l1_table, new_l1_size2);
1.1.1.5 root 80: if (ret < 0)
1.1 root 81: goto fail;
82: for(i = 0; i < s->l1_size; i++)
83: new_l1_table[i] = be64_to_cpu(new_l1_table[i]);
84:
85: /* set new table */
1.1.1.6 root 86: BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_ACTIVATE_TABLE);
1.1 root 87: cpu_to_be32w((uint32_t*)data, new_l1_size);
1.1.1.7 ! root 88: cpu_to_be64wu((uint64_t*)(data + 4), new_l1_table_offset);
1.1.1.6 root 89: ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, l1_size), data,sizeof(data));
1.1.1.5 root 90: if (ret < 0) {
1.1 root 91: goto fail;
1.1.1.3 root 92: }
1.1 root 93: qemu_free(s->l1_table);
94: qcow2_free_clusters(bs, s->l1_table_offset, s->l1_size * sizeof(uint64_t));
95: s->l1_table_offset = new_l1_table_offset;
96: s->l1_table = new_l1_table;
97: s->l1_size = new_l1_size;
98: return 0;
99: fail:
1.1.1.3 root 100: qemu_free(new_l1_table);
101: qcow2_free_clusters(bs, new_l1_table_offset, new_l1_size2);
1.1.1.5 root 102: return ret;
1.1 root 103: }
104:
105: /*
106: * l2_load
107: *
108: * Loads a L2 table into memory. If the table is in the cache, the cache
109: * is used; otherwise the L2 table is loaded from the image file.
110: *
111: * Returns a pointer to the L2 table on success, or NULL if the read from
112: * the image file failed.
113: */
114:
1.1.1.6 root 115: static int l2_load(BlockDriverState *bs, uint64_t l2_offset,
116: uint64_t **l2_table)
1.1 root 117: {
118: BDRVQcowState *s = bs->opaque;
1.1.1.6 root 119: int ret;
1.1 root 120:
1.1.1.7 ! root 121: ret = qcow2_cache_get(bs, s->l2_table_cache, l2_offset, (void**) l2_table);
1.1 root 122:
1.1.1.7 ! root 123: return ret;
1.1 root 124: }
125:
126: /*
127: * Writes one sector of the L1 table to the disk (can't update single entries
128: * and we really don't want bdrv_pread to perform a read-modify-write)
129: */
130: #define L1_ENTRIES_PER_SECTOR (512 / 8)
1.1.1.6 root 131: static int write_l1_entry(BlockDriverState *bs, int l1_index)
1.1 root 132: {
1.1.1.6 root 133: BDRVQcowState *s = bs->opaque;
1.1 root 134: uint64_t buf[L1_ENTRIES_PER_SECTOR];
135: int l1_start_index;
1.1.1.5 root 136: int i, ret;
1.1 root 137:
138: l1_start_index = l1_index & ~(L1_ENTRIES_PER_SECTOR - 1);
139: for (i = 0; i < L1_ENTRIES_PER_SECTOR; i++) {
140: buf[i] = cpu_to_be64(s->l1_table[l1_start_index + i]);
141: }
142:
1.1.1.6 root 143: BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE);
144: ret = bdrv_pwrite_sync(bs->file, s->l1_table_offset + 8 * l1_start_index,
1.1.1.5 root 145: buf, sizeof(buf));
146: if (ret < 0) {
147: return ret;
1.1 root 148: }
149:
150: return 0;
151: }
152:
153: /*
154: * l2_allocate
155: *
156: * Allocate a new l2 entry in the file. If l1_index points to an already
157: * used entry in the L2 table (i.e. we are doing a copy on write for the L2
158: * table) copy the contents of the old L2 table into the newly allocated one.
159: * Otherwise the new table is initialized with zeros.
160: *
161: */
162:
1.1.1.6 root 163: static int l2_allocate(BlockDriverState *bs, int l1_index, uint64_t **table)
1.1 root 164: {
165: BDRVQcowState *s = bs->opaque;
166: uint64_t old_l2_offset;
1.1.1.3 root 167: uint64_t *l2_table;
168: int64_t l2_offset;
1.1.1.5 root 169: int ret;
1.1 root 170:
171: old_l2_offset = s->l1_table[l1_index];
172:
173: /* allocate a new l2 entry */
174:
175: l2_offset = qcow2_alloc_clusters(bs, s->l2_size * sizeof(uint64_t));
1.1.1.3 root 176: if (l2_offset < 0) {
1.1.1.6 root 177: return l2_offset;
1.1.1.3 root 178: }
1.1 root 179:
1.1.1.7 ! root 180: ret = qcow2_cache_flush(bs, s->refcount_block_cache);
! 181: if (ret < 0) {
! 182: goto fail;
! 183: }
! 184:
1.1 root 185: /* allocate a new entry in the l2 cache */
186:
1.1.1.7 ! root 187: ret = qcow2_cache_get_empty(bs, s->l2_table_cache, l2_offset, (void**) table);
! 188: if (ret < 0) {
! 189: return ret;
! 190: }
! 191:
! 192: l2_table = *table;
1.1 root 193:
194: if (old_l2_offset == 0) {
195: /* if there was no old l2 table, clear the new table */
196: memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
197: } else {
1.1.1.7 ! root 198: uint64_t* old_table;
! 199:
1.1 root 200: /* if there was an old l2 table, read it from the disk */
1.1.1.6 root 201: BLKDBG_EVENT(bs->file, BLKDBG_L2_ALLOC_COW_READ);
1.1.1.7 ! root 202: ret = qcow2_cache_get(bs, s->l2_table_cache, old_l2_offset,
! 203: (void**) &old_table);
! 204: if (ret < 0) {
! 205: goto fail;
! 206: }
! 207:
! 208: memcpy(l2_table, old_table, s->cluster_size);
! 209:
! 210: ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &old_table);
1.1.1.6 root 211: if (ret < 0) {
1.1.1.5 root 212: goto fail;
1.1.1.6 root 213: }
1.1 root 214: }
1.1.1.7 ! root 215:
1.1 root 216: /* write the l2 table to the file */
1.1.1.6 root 217: BLKDBG_EVENT(bs->file, BLKDBG_L2_ALLOC_WRITE);
1.1.1.7 ! root 218:
! 219: qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table);
! 220: ret = qcow2_cache_flush(bs, s->l2_table_cache);
1.1.1.5 root 221: if (ret < 0) {
222: goto fail;
223: }
224:
225: /* update the L1 entry */
226: s->l1_table[l1_index] = l2_offset | QCOW_OFLAG_COPIED;
1.1.1.6 root 227: ret = write_l1_entry(bs, l1_index);
228: if (ret < 0) {
1.1.1.5 root 229: goto fail;
230: }
1.1 root 231:
1.1.1.6 root 232: *table = l2_table;
233: return 0;
1.1.1.5 root 234:
235: fail:
1.1.1.7 ! root 236: qcow2_cache_put(bs, s->l2_table_cache, (void**) table);
1.1.1.5 root 237: s->l1_table[l1_index] = old_l2_offset;
1.1.1.6 root 238: return ret;
1.1 root 239: }
240:
241: static int count_contiguous_clusters(uint64_t nb_clusters, int cluster_size,
242: uint64_t *l2_table, uint64_t start, uint64_t mask)
243: {
244: int i;
245: uint64_t offset = be64_to_cpu(l2_table[0]) & ~mask;
246:
247: if (!offset)
248: return 0;
249:
250: for (i = start; i < start + nb_clusters; i++)
1.1.1.2 root 251: if (offset + (uint64_t) i * cluster_size != (be64_to_cpu(l2_table[i]) & ~mask))
1.1 root 252: break;
253:
254: return (i - start);
255: }
256:
257: static int count_contiguous_free_clusters(uint64_t nb_clusters, uint64_t *l2_table)
258: {
259: int i = 0;
260:
261: while(nb_clusters-- && l2_table[i] == 0)
262: i++;
263:
264: return i;
265: }
266:
267: /* The crypt function is compatible with the linux cryptoloop
268: algorithm for < 4 GB images. NOTE: out_buf == in_buf is
269: supported */
270: void qcow2_encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
271: uint8_t *out_buf, const uint8_t *in_buf,
272: int nb_sectors, int enc,
273: const AES_KEY *key)
274: {
275: union {
276: uint64_t ll[2];
277: uint8_t b[16];
278: } ivec;
279: int i;
280:
281: for(i = 0; i < nb_sectors; i++) {
282: ivec.ll[0] = cpu_to_le64(sector_num);
283: ivec.ll[1] = 0;
284: AES_cbc_encrypt(in_buf, out_buf, 512, key,
285: ivec.b, enc);
286: sector_num++;
287: in_buf += 512;
288: out_buf += 512;
289: }
290: }
291:
292:
1.1.1.7 ! root 293: static int qcow2_read(BlockDriverState *bs, int64_t sector_num,
! 294: uint8_t *buf, int nb_sectors)
1.1 root 295: {
296: BDRVQcowState *s = bs->opaque;
297: int ret, index_in_cluster, n, n1;
298: uint64_t cluster_offset;
1.1.1.7 ! root 299: struct iovec iov;
! 300: QEMUIOVector qiov;
1.1 root 301:
302: while (nb_sectors > 0) {
303: n = nb_sectors;
1.1.1.6 root 304:
305: ret = qcow2_get_cluster_offset(bs, sector_num << 9, &n,
306: &cluster_offset);
307: if (ret < 0) {
308: return ret;
309: }
310:
1.1 root 311: index_in_cluster = sector_num & (s->cluster_sectors - 1);
312: if (!cluster_offset) {
313: if (bs->backing_hd) {
314: /* read from the base image */
1.1.1.7 ! root 315: iov.iov_base = buf;
! 316: iov.iov_len = n * 512;
! 317: qemu_iovec_init_external(&qiov, &iov, 1);
! 318:
! 319: n1 = qcow2_backing_read1(bs->backing_hd, &qiov, sector_num, n);
1.1 root 320: if (n1 > 0) {
1.1.1.6 root 321: BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING);
1.1 root 322: ret = bdrv_read(bs->backing_hd, sector_num, buf, n1);
323: if (ret < 0)
324: return -1;
325: }
326: } else {
327: memset(buf, 0, 512 * n);
328: }
329: } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
1.1.1.6 root 330: if (qcow2_decompress_cluster(bs, cluster_offset) < 0)
1.1 root 331: return -1;
332: memcpy(buf, s->cluster_cache + index_in_cluster * 512, 512 * n);
333: } else {
1.1.1.6 root 334: BLKDBG_EVENT(bs->file, BLKDBG_READ);
335: ret = bdrv_pread(bs->file, cluster_offset + index_in_cluster * 512, buf, n * 512);
1.1 root 336: if (ret != n * 512)
337: return -1;
338: if (s->crypt_method) {
339: qcow2_encrypt_sectors(s, sector_num, buf, buf, n, 0,
340: &s->aes_decrypt_key);
341: }
342: }
343: nb_sectors -= n;
344: sector_num += n;
345: buf += n * 512;
346: }
347: return 0;
348: }
349:
350: static int copy_sectors(BlockDriverState *bs, uint64_t start_sect,
351: uint64_t cluster_offset, int n_start, int n_end)
352: {
353: BDRVQcowState *s = bs->opaque;
354: int n, ret;
355:
356: n = n_end - n_start;
357: if (n <= 0)
358: return 0;
1.1.1.6 root 359: BLKDBG_EVENT(bs->file, BLKDBG_COW_READ);
1.1.1.7 ! root 360: ret = qcow2_read(bs, start_sect + n_start, s->cluster_data, n);
1.1 root 361: if (ret < 0)
362: return ret;
363: if (s->crypt_method) {
364: qcow2_encrypt_sectors(s, start_sect + n_start,
365: s->cluster_data,
366: s->cluster_data, n, 1,
367: &s->aes_encrypt_key);
368: }
1.1.1.6 root 369: BLKDBG_EVENT(bs->file, BLKDBG_COW_WRITE);
1.1.1.7 ! root 370: ret = bdrv_write(bs->file, (cluster_offset >> 9) + n_start,
1.1.1.5 root 371: s->cluster_data, n);
1.1 root 372: if (ret < 0)
373: return ret;
374: return 0;
375: }
376:
377:
378: /*
379: * get_cluster_offset
380: *
1.1.1.6 root 381: * For a given offset of the disk image, find the cluster offset in
382: * qcow2 file. The offset is stored in *cluster_offset.
1.1 root 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: *
1.1.1.6 root 389: * Return 0, if the offset is found
390: * Return -errno, otherwise.
1.1 root 391: *
392: */
393:
1.1.1.6 root 394: int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,
395: int *num, uint64_t *cluster_offset)
1.1 root 396: {
397: BDRVQcowState *s = bs->opaque;
1.1.1.2 root 398: unsigned int l1_index, l2_index;
1.1.1.6 root 399: uint64_t l2_offset, *l2_table;
1.1 root 400: int l1_bits, c;
1.1.1.2 root 401: unsigned int index_in_cluster, nb_clusters;
402: uint64_t nb_available, nb_needed;
1.1.1.6 root 403: int ret;
1.1 root 404:
405: index_in_cluster = (offset >> 9) & (s->cluster_sectors - 1);
406: nb_needed = *num + index_in_cluster;
407:
408: l1_bits = s->l2_bits + s->cluster_bits;
409:
410: /* compute how many bytes there are between the offset and
411: * the end of the l1 entry
412: */
413:
1.1.1.2 root 414: nb_available = (1ULL << l1_bits) - (offset & ((1ULL << l1_bits) - 1));
1.1 root 415:
416: /* compute the number of available sectors */
417:
418: nb_available = (nb_available >> 9) + index_in_cluster;
419:
420: if (nb_needed > nb_available) {
421: nb_needed = nb_available;
422: }
423:
1.1.1.6 root 424: *cluster_offset = 0;
1.1 root 425:
426: /* seek the the l2 offset in the l1 table */
427:
428: l1_index = offset >> l1_bits;
429: if (l1_index >= s->l1_size)
430: goto out;
431:
432: l2_offset = s->l1_table[l1_index];
433:
434: /* seek the l2 table of the given l2 offset */
435:
436: if (!l2_offset)
437: goto out;
438:
439: /* load the l2 table in memory */
440:
441: l2_offset &= ~QCOW_OFLAG_COPIED;
1.1.1.6 root 442: ret = l2_load(bs, l2_offset, &l2_table);
443: if (ret < 0) {
444: return ret;
445: }
1.1 root 446:
447: /* find the cluster offset for the given disk offset */
448:
449: l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
1.1.1.6 root 450: *cluster_offset = be64_to_cpu(l2_table[l2_index]);
1.1 root 451: nb_clusters = size_to_clusters(s, nb_needed << 9);
452:
1.1.1.6 root 453: if (!*cluster_offset) {
1.1 root 454: /* how many empty clusters ? */
455: c = count_contiguous_free_clusters(nb_clusters, &l2_table[l2_index]);
456: } else {
457: /* how many allocated clusters ? */
458: c = count_contiguous_clusters(nb_clusters, s->cluster_size,
459: &l2_table[l2_index], 0, QCOW_OFLAG_COPIED);
460: }
461:
1.1.1.7 ! root 462: qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
! 463:
1.1 root 464: nb_available = (c * s->cluster_sectors);
465: out:
466: if (nb_available > nb_needed)
467: nb_available = nb_needed;
468:
469: *num = nb_available - index_in_cluster;
470:
1.1.1.6 root 471: *cluster_offset &=~QCOW_OFLAG_COPIED;
472: return 0;
1.1 root 473: }
474:
475: /*
476: * get_cluster_table
477: *
478: * for a given disk offset, load (and allocate if needed)
479: * the l2 table.
480: *
481: * the l2 table offset in the qcow2 file and the cluster index
482: * in the l2 table are given to the caller.
483: *
1.1.1.3 root 484: * Returns 0 on success, -errno in failure case
1.1 root 485: */
486: static int get_cluster_table(BlockDriverState *bs, uint64_t offset,
487: uint64_t **new_l2_table,
488: uint64_t *new_l2_offset,
489: int *new_l2_index)
490: {
491: BDRVQcowState *s = bs->opaque;
1.1.1.2 root 492: unsigned int l1_index, l2_index;
1.1.1.6 root 493: uint64_t l2_offset;
494: uint64_t *l2_table = NULL;
1.1.1.2 root 495: int ret;
1.1 root 496:
497: /* seek the the l2 offset in the l1 table */
498:
499: l1_index = offset >> (s->l2_bits + s->cluster_bits);
500: if (l1_index >= s->l1_size) {
1.1.1.7 ! root 501: ret = qcow2_grow_l1_table(bs, l1_index + 1, false);
1.1.1.3 root 502: if (ret < 0) {
503: return ret;
504: }
1.1 root 505: }
506: l2_offset = s->l1_table[l1_index];
507:
508: /* seek the l2 table of the given l2 offset */
509:
510: if (l2_offset & QCOW_OFLAG_COPIED) {
511: /* load the l2 table in memory */
512: l2_offset &= ~QCOW_OFLAG_COPIED;
1.1.1.6 root 513: ret = l2_load(bs, l2_offset, &l2_table);
514: if (ret < 0) {
515: return ret;
1.1.1.3 root 516: }
1.1 root 517: } else {
1.1.1.7 ! root 518: /* First allocate a new L2 table (and do COW if needed) */
1.1.1.6 root 519: ret = l2_allocate(bs, l1_index, &l2_table);
520: if (ret < 0) {
521: return ret;
1.1.1.3 root 522: }
1.1.1.7 ! root 523:
! 524: /* Then decrease the refcount of the old table */
! 525: if (l2_offset) {
! 526: qcow2_free_clusters(bs, l2_offset, s->l2_size * sizeof(uint64_t));
! 527: }
1.1 root 528: l2_offset = s->l1_table[l1_index] & ~QCOW_OFLAG_COPIED;
529: }
530:
531: /* find the cluster offset for the given disk offset */
532:
533: l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
534:
535: *new_l2_table = l2_table;
536: *new_l2_offset = l2_offset;
537: *new_l2_index = l2_index;
538:
1.1.1.3 root 539: return 0;
1.1 root 540: }
541:
542: /*
543: * alloc_compressed_cluster_offset
544: *
545: * For a given offset of the disk image, return cluster offset in
546: * qcow2 file.
547: *
548: * If the offset is not found, allocate a new compressed cluster.
549: *
550: * Return the cluster offset if successful,
551: * Return 0, otherwise.
552: *
553: */
554:
555: uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
556: uint64_t offset,
557: int compressed_size)
558: {
559: BDRVQcowState *s = bs->opaque;
560: int l2_index, ret;
1.1.1.3 root 561: uint64_t l2_offset, *l2_table;
562: int64_t cluster_offset;
1.1 root 563: int nb_csectors;
564:
565: ret = get_cluster_table(bs, offset, &l2_table, &l2_offset, &l2_index);
1.1.1.3 root 566: if (ret < 0) {
1.1 root 567: return 0;
1.1.1.3 root 568: }
1.1 root 569:
570: cluster_offset = be64_to_cpu(l2_table[l2_index]);
571: if (cluster_offset & QCOW_OFLAG_COPIED)
572: return cluster_offset & ~QCOW_OFLAG_COPIED;
573:
574: if (cluster_offset)
575: qcow2_free_any_clusters(bs, cluster_offset, 1);
576:
577: cluster_offset = qcow2_alloc_bytes(bs, compressed_size);
1.1.1.3 root 578: if (cluster_offset < 0) {
1.1.1.7 ! root 579: qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
1.1.1.3 root 580: return 0;
581: }
582:
1.1 root 583: nb_csectors = ((cluster_offset + compressed_size - 1) >> 9) -
584: (cluster_offset >> 9);
585:
586: cluster_offset |= QCOW_OFLAG_COMPRESSED |
587: ((uint64_t)nb_csectors << s->csize_shift);
588:
589: /* update L2 table */
590:
591: /* compressed clusters never have the copied flag */
592:
1.1.1.6 root 593: BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE_COMPRESSED);
1.1.1.7 ! root 594: qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table);
1.1 root 595: l2_table[l2_index] = cpu_to_be64(cluster_offset);
1.1.1.7 ! root 596: ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
1.1.1.5 root 597: if (ret < 0) {
1.1.1.7 ! root 598: return 0;
1.1 root 599: }
600:
1.1.1.7 ! root 601: return cluster_offset;
1.1 root 602: }
603:
1.1.1.3 root 604: int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m)
1.1 root 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;
1.1.1.3 root 609: uint64_t cluster_offset = m->cluster_offset;
1.1.1.7 ! root 610: bool cow = false;
1.1 root 611:
612: if (m->nb_clusters == 0)
613: return 0;
614:
615: old_cluster = qemu_malloc(m->nb_clusters * sizeof(uint64_t));
616:
617: /* copy content of unmodified sectors */
618: start_sect = (m->offset & ~(s->cluster_size - 1)) >> 9;
619: if (m->n_start) {
1.1.1.7 ! root 620: cow = true;
1.1 root 621: ret = copy_sectors(bs, start_sect, cluster_offset, 0, m->n_start);
622: if (ret < 0)
623: goto err;
624: }
625:
626: if (m->nb_available & (s->cluster_sectors - 1)) {
627: uint64_t end = m->nb_available & ~(uint64_t)(s->cluster_sectors - 1);
1.1.1.7 ! root 628: cow = true;
1.1 root 629: ret = copy_sectors(bs, start_sect + end, cluster_offset + (end << 9),
630: m->nb_available - end, s->cluster_sectors);
631: if (ret < 0)
632: goto err;
633: }
634:
1.1.1.7 ! root 635: /*
! 636: * Update L2 table.
! 637: *
! 638: * Before we update the L2 table to actually point to the new cluster, we
! 639: * need to be sure that the refcounts have been increased and COW was
! 640: * handled.
! 641: */
! 642: if (cow) {
! 643: qcow2_cache_depends_on_flush(s->l2_table_cache);
! 644: }
! 645:
! 646: qcow2_cache_set_dependency(bs, s->l2_table_cache, s->refcount_block_cache);
1.1.1.3 root 647: ret = get_cluster_table(bs, m->offset, &l2_table, &l2_offset, &l2_index);
648: if (ret < 0) {
1.1 root 649: goto err;
1.1.1.3 root 650: }
1.1.1.7 ! root 651: qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table);
1.1 root 652:
653: for (i = 0; i < m->nb_clusters; i++) {
654: /* if two concurrent writes happen to the same unallocated cluster
655: * each write allocates separate cluster and writes data concurrently.
656: * The first one to complete updates l2 table with pointer to its
657: * cluster the second one has to do RMW (which is done above by
658: * copy_sectors()), update l2 table with its cluster pointer and free
659: * old cluster. This is what this loop does */
660: if(l2_table[l2_index + i] != 0)
661: old_cluster[j++] = l2_table[l2_index + i];
662:
663: l2_table[l2_index + i] = cpu_to_be64((cluster_offset +
664: (i << s->cluster_bits)) | QCOW_OFLAG_COPIED);
665: }
666:
1.1.1.7 ! root 667:
! 668: ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
1.1.1.5 root 669: if (ret < 0) {
1.1 root 670: goto err;
671: }
672:
1.1.1.6 root 673: /*
674: * If this was a COW, we need to decrease the refcount of the old cluster.
675: * Also flush bs->file to get the right order for L2 and refcount update.
676: */
677: if (j != 0) {
678: for (i = 0; i < j; i++) {
679: qcow2_free_any_clusters(bs,
680: be64_to_cpu(old_cluster[i]) & ~QCOW_OFLAG_COPIED, 1);
681: }
682: }
1.1 root 683:
684: ret = 0;
685: err:
686: qemu_free(old_cluster);
687: return ret;
688: }
689:
690: /*
691: * alloc_cluster_offset
692: *
1.1.1.3 root 693: * For a given offset of the disk image, return cluster offset in qcow2 file.
1.1 root 694: * If the offset is not found, allocate a new cluster.
695: *
1.1.1.3 root 696: * If the cluster was already allocated, m->nb_clusters is set to 0,
697: * m->depends_on is set to NULL and the other fields in m are meaningless.
1.1 root 698: *
1.1.1.3 root 699: * If the cluster is newly allocated, m->nb_clusters is set to the number of
700: * contiguous clusters that have been allocated. This may be 0 if the request
701: * conflict with another write request in flight; in this case, m->depends_on
702: * is set and the remaining fields of m are meaningless.
703: *
704: * If m->nb_clusters is non-zero, the other fields of m are valid and contain
705: * information about the first allocated cluster.
706: *
707: * Return 0 on success and -errno in error cases
1.1 root 708: */
1.1.1.3 root 709: int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,
710: int n_start, int n_end, int *num, QCowL2Meta *m)
1.1 root 711: {
712: BDRVQcowState *s = bs->opaque;
713: int l2_index, ret;
1.1.1.3 root 714: uint64_t l2_offset, *l2_table;
715: int64_t cluster_offset;
1.1.1.2 root 716: unsigned int nb_clusters, i = 0;
1.1 root 717: QCowL2Meta *old_alloc;
718:
719: ret = get_cluster_table(bs, offset, &l2_table, &l2_offset, &l2_index);
1.1.1.3 root 720: if (ret < 0) {
721: return ret;
722: }
1.1 root 723:
724: nb_clusters = size_to_clusters(s, n_end << 9);
725:
726: nb_clusters = MIN(nb_clusters, s->l2_size - l2_index);
727:
728: cluster_offset = be64_to_cpu(l2_table[l2_index]);
729:
730: /* We keep all QCOW_OFLAG_COPIED clusters */
731:
732: if (cluster_offset & QCOW_OFLAG_COPIED) {
733: nb_clusters = count_contiguous_clusters(nb_clusters, s->cluster_size,
734: &l2_table[l2_index], 0, 0);
735:
736: cluster_offset &= ~QCOW_OFLAG_COPIED;
737: m->nb_clusters = 0;
1.1.1.3 root 738: m->depends_on = NULL;
1.1 root 739:
740: goto out;
741: }
742:
743: /* for the moment, multiple compressed clusters are not managed */
744:
745: if (cluster_offset & QCOW_OFLAG_COMPRESSED)
746: nb_clusters = 1;
747:
748: /* how many available clusters ? */
749:
750: while (i < nb_clusters) {
751: i += count_contiguous_clusters(nb_clusters - i, s->cluster_size,
752: &l2_table[l2_index], i, 0);
1.1.1.3 root 753: if ((i >= nb_clusters) || be64_to_cpu(l2_table[l2_index + i])) {
1.1 root 754: break;
1.1.1.3 root 755: }
1.1 root 756:
757: i += count_contiguous_free_clusters(nb_clusters - i,
758: &l2_table[l2_index + i]);
1.1.1.3 root 759: if (i >= nb_clusters) {
760: break;
761: }
1.1 root 762:
763: cluster_offset = be64_to_cpu(l2_table[l2_index + i]);
764:
765: if ((cluster_offset & QCOW_OFLAG_COPIED) ||
766: (cluster_offset & QCOW_OFLAG_COMPRESSED))
767: break;
768: }
1.1.1.3 root 769: assert(i <= nb_clusters);
1.1 root 770: nb_clusters = i;
771:
772: /*
773: * Check if there already is an AIO write request in flight which allocates
774: * the same cluster. In this case we need to wait until the previous
775: * request has completed and updated the L2 table accordingly.
776: */
1.1.1.2 root 777: QLIST_FOREACH(old_alloc, &s->cluster_allocs, next_in_flight) {
1.1 root 778:
779: uint64_t end_offset = offset + nb_clusters * s->cluster_size;
780: uint64_t old_offset = old_alloc->offset;
781: uint64_t old_end_offset = old_alloc->offset +
782: old_alloc->nb_clusters * s->cluster_size;
783:
784: if (end_offset < old_offset || offset > old_end_offset) {
785: /* No intersection */
786: } else {
787: if (offset < old_offset) {
788: /* Stop at the start of a running allocation */
789: nb_clusters = (old_offset - offset) >> s->cluster_bits;
790: } else {
791: nb_clusters = 0;
792: }
793:
794: if (nb_clusters == 0) {
795: /* Set dependency and wait for a callback */
796: m->depends_on = old_alloc;
797: m->nb_clusters = 0;
798: *num = 0;
1.1.1.7 ! root 799: ret = 0;
! 800: goto fail;
1.1 root 801: }
802: }
803: }
804:
805: if (!nb_clusters) {
806: abort();
807: }
808:
1.1.1.2 root 809: QLIST_INSERT_HEAD(&s->cluster_allocs, m, next_in_flight);
1.1 root 810:
811: /* allocate a new cluster */
812:
813: cluster_offset = qcow2_alloc_clusters(bs, nb_clusters * s->cluster_size);
1.1.1.3 root 814: if (cluster_offset < 0) {
1.1.1.4 root 815: QLIST_REMOVE(m, next_in_flight);
1.1.1.7 ! root 816: ret = cluster_offset;
! 817: goto fail;
1.1.1.3 root 818: }
1.1 root 819:
820: /* save info needed for meta data update */
821: m->offset = offset;
822: m->n_start = n_start;
823: m->nb_clusters = nb_clusters;
824:
825: out:
1.1.1.7 ! root 826: ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
! 827: if (ret < 0) {
! 828: return ret;
! 829: }
! 830:
1.1 root 831: m->nb_available = MIN(nb_clusters << (s->cluster_bits - 9), n_end);
1.1.1.3 root 832: m->cluster_offset = cluster_offset;
1.1 root 833:
834: *num = m->nb_available - n_start;
835:
1.1.1.3 root 836: return 0;
1.1.1.7 ! root 837:
! 838: fail:
! 839: qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
! 840: return ret;
1.1 root 841: }
842:
843: static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
844: const uint8_t *buf, int buf_size)
845: {
846: z_stream strm1, *strm = &strm1;
847: int ret, out_len;
848:
849: memset(strm, 0, sizeof(*strm));
850:
851: strm->next_in = (uint8_t *)buf;
852: strm->avail_in = buf_size;
853: strm->next_out = out_buf;
854: strm->avail_out = out_buf_size;
855:
856: ret = inflateInit2(strm, -12);
857: if (ret != Z_OK)
858: return -1;
859: ret = inflate(strm, Z_FINISH);
860: out_len = strm->next_out - out_buf;
861: if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) ||
862: out_len != out_buf_size) {
863: inflateEnd(strm);
864: return -1;
865: }
866: inflateEnd(strm);
867: return 0;
868: }
869:
1.1.1.6 root 870: int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset)
1.1 root 871: {
1.1.1.6 root 872: BDRVQcowState *s = bs->opaque;
1.1 root 873: int ret, csize, nb_csectors, sector_offset;
874: uint64_t coffset;
875:
876: coffset = cluster_offset & s->cluster_offset_mask;
877: if (s->cluster_cache_offset != coffset) {
878: nb_csectors = ((cluster_offset >> s->csize_shift) & s->csize_mask) + 1;
879: sector_offset = coffset & 511;
880: csize = nb_csectors * 512 - sector_offset;
1.1.1.6 root 881: BLKDBG_EVENT(bs->file, BLKDBG_READ_COMPRESSED);
882: ret = bdrv_read(bs->file, coffset >> 9, s->cluster_data, nb_csectors);
1.1 root 883: if (ret < 0) {
1.1.1.7 ! root 884: return ret;
1.1 root 885: }
886: if (decompress_buffer(s->cluster_cache, s->cluster_size,
887: s->cluster_data + sector_offset, csize) < 0) {
1.1.1.7 ! root 888: return -EIO;
1.1 root 889: }
890: s->cluster_cache_offset = coffset;
891: }
892: return 0;
893: }
1.1.1.7 ! root 894:
! 895: /*
! 896: * This discards as many clusters of nb_clusters as possible at once (i.e.
! 897: * all clusters in the same L2 table) and returns the number of discarded
! 898: * clusters.
! 899: */
! 900: static int discard_single_l2(BlockDriverState *bs, uint64_t offset,
! 901: unsigned int nb_clusters)
! 902: {
! 903: BDRVQcowState *s = bs->opaque;
! 904: uint64_t l2_offset, *l2_table;
! 905: int l2_index;
! 906: int ret;
! 907: int i;
! 908:
! 909: ret = get_cluster_table(bs, offset, &l2_table, &l2_offset, &l2_index);
! 910: if (ret < 0) {
! 911: return ret;
! 912: }
! 913:
! 914: /* Limit nb_clusters to one L2 table */
! 915: nb_clusters = MIN(nb_clusters, s->l2_size - l2_index);
! 916:
! 917: for (i = 0; i < nb_clusters; i++) {
! 918: uint64_t old_offset;
! 919:
! 920: old_offset = be64_to_cpu(l2_table[l2_index + i]);
! 921: old_offset &= ~QCOW_OFLAG_COPIED;
! 922:
! 923: if (old_offset == 0) {
! 924: continue;
! 925: }
! 926:
! 927: /* First remove L2 entries */
! 928: qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table);
! 929: l2_table[l2_index + i] = cpu_to_be64(0);
! 930:
! 931: /* Then decrease the refcount */
! 932: qcow2_free_any_clusters(bs, old_offset, 1);
! 933: }
! 934:
! 935: ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
! 936: if (ret < 0) {
! 937: return ret;
! 938: }
! 939:
! 940: return nb_clusters;
! 941: }
! 942:
! 943: int qcow2_discard_clusters(BlockDriverState *bs, uint64_t offset,
! 944: int nb_sectors)
! 945: {
! 946: BDRVQcowState *s = bs->opaque;
! 947: uint64_t end_offset;
! 948: unsigned int nb_clusters;
! 949: int ret;
! 950:
! 951: end_offset = offset + (nb_sectors << BDRV_SECTOR_BITS);
! 952:
! 953: /* Round start up and end down */
! 954: offset = align_offset(offset, s->cluster_size);
! 955: end_offset &= ~(s->cluster_size - 1);
! 956:
! 957: if (offset > end_offset) {
! 958: return 0;
! 959: }
! 960:
! 961: nb_clusters = size_to_clusters(s, end_offset - offset);
! 962:
! 963: /* Each L2 table is handled by its own loop iteration */
! 964: while (nb_clusters > 0) {
! 965: ret = discard_single_l2(bs, offset, nb_clusters);
! 966: if (ret < 0) {
! 967: return ret;
! 968: }
! 969:
! 970: nb_clusters -= ret;
! 971: offset += (ret * s->cluster_size);
! 972: }
! 973:
! 974: return 0;
! 975: }
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