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45aba42f KW |
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" | |
3cce16f4 | 30 | #include "trace.h" |
45aba42f | 31 | |
72893756 | 32 | int qcow2_grow_l1_table(BlockDriverState *bs, int min_size, bool exact_size) |
45aba42f KW |
33 | { |
34 | BDRVQcowState *s = bs->opaque; | |
35 | int new_l1_size, new_l1_size2, ret, i; | |
36 | uint64_t *new_l1_table; | |
5d757b56 | 37 | int64_t new_l1_table_offset; |
45aba42f KW |
38 | uint8_t data[12]; |
39 | ||
72893756 | 40 | if (min_size <= s->l1_size) |
45aba42f | 41 | return 0; |
72893756 SH |
42 | |
43 | if (exact_size) { | |
44 | new_l1_size = min_size; | |
45 | } else { | |
46 | /* Bump size up to reduce the number of times we have to grow */ | |
47 | new_l1_size = s->l1_size; | |
48 | if (new_l1_size == 0) { | |
49 | new_l1_size = 1; | |
50 | } | |
51 | while (min_size > new_l1_size) { | |
52 | new_l1_size = (new_l1_size * 3 + 1) / 2; | |
53 | } | |
45aba42f | 54 | } |
72893756 | 55 | |
45aba42f | 56 | #ifdef DEBUG_ALLOC2 |
35ee5e39 | 57 | fprintf(stderr, "grow l1_table from %d to %d\n", s->l1_size, new_l1_size); |
45aba42f KW |
58 | #endif |
59 | ||
60 | new_l1_size2 = sizeof(uint64_t) * new_l1_size; | |
7267c094 | 61 | new_l1_table = g_malloc0(align_offset(new_l1_size2, 512)); |
45aba42f KW |
62 | memcpy(new_l1_table, s->l1_table, s->l1_size * sizeof(uint64_t)); |
63 | ||
64 | /* write new table (align to cluster) */ | |
66f82cee | 65 | BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_ALLOC_TABLE); |
ed6ccf0f | 66 | new_l1_table_offset = qcow2_alloc_clusters(bs, new_l1_size2); |
5d757b56 | 67 | if (new_l1_table_offset < 0) { |
7267c094 | 68 | g_free(new_l1_table); |
5d757b56 KW |
69 | return new_l1_table_offset; |
70 | } | |
29c1a730 KW |
71 | |
72 | ret = qcow2_cache_flush(bs, s->refcount_block_cache); | |
73 | if (ret < 0) { | |
80fa3341 | 74 | goto fail; |
29c1a730 | 75 | } |
45aba42f | 76 | |
66f82cee | 77 | BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_WRITE_TABLE); |
45aba42f KW |
78 | for(i = 0; i < s->l1_size; i++) |
79 | new_l1_table[i] = cpu_to_be64(new_l1_table[i]); | |
8b3b7206 KW |
80 | ret = bdrv_pwrite_sync(bs->file, new_l1_table_offset, new_l1_table, new_l1_size2); |
81 | if (ret < 0) | |
45aba42f KW |
82 | goto fail; |
83 | for(i = 0; i < s->l1_size; i++) | |
84 | new_l1_table[i] = be64_to_cpu(new_l1_table[i]); | |
85 | ||
86 | /* set new table */ | |
66f82cee | 87 | BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_ACTIVATE_TABLE); |
45aba42f | 88 | cpu_to_be32w((uint32_t*)data, new_l1_size); |
653df36b | 89 | cpu_to_be64wu((uint64_t*)(data + 4), new_l1_table_offset); |
8b3b7206 KW |
90 | ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, l1_size), data,sizeof(data)); |
91 | if (ret < 0) { | |
45aba42f | 92 | goto fail; |
fb8fa77c | 93 | } |
7267c094 | 94 | g_free(s->l1_table); |
ed6ccf0f | 95 | qcow2_free_clusters(bs, s->l1_table_offset, s->l1_size * sizeof(uint64_t)); |
45aba42f KW |
96 | s->l1_table_offset = new_l1_table_offset; |
97 | s->l1_table = new_l1_table; | |
98 | s->l1_size = new_l1_size; | |
99 | return 0; | |
100 | fail: | |
7267c094 | 101 | g_free(new_l1_table); |
fb8fa77c | 102 | qcow2_free_clusters(bs, new_l1_table_offset, new_l1_size2); |
8b3b7206 | 103 | return ret; |
45aba42f KW |
104 | } |
105 | ||
45aba42f KW |
106 | /* |
107 | * l2_load | |
108 | * | |
109 | * Loads a L2 table into memory. If the table is in the cache, the cache | |
110 | * is used; otherwise the L2 table is loaded from the image file. | |
111 | * | |
112 | * Returns a pointer to the L2 table on success, or NULL if the read from | |
113 | * the image file failed. | |
114 | */ | |
115 | ||
55c17e98 KW |
116 | static int l2_load(BlockDriverState *bs, uint64_t l2_offset, |
117 | uint64_t **l2_table) | |
45aba42f KW |
118 | { |
119 | BDRVQcowState *s = bs->opaque; | |
55c17e98 | 120 | int ret; |
45aba42f | 121 | |
29c1a730 | 122 | ret = qcow2_cache_get(bs, s->l2_table_cache, l2_offset, (void**) l2_table); |
45aba42f | 123 | |
29c1a730 | 124 | return ret; |
45aba42f KW |
125 | } |
126 | ||
6583e3c7 KW |
127 | /* |
128 | * Writes one sector of the L1 table to the disk (can't update single entries | |
129 | * and we really don't want bdrv_pread to perform a read-modify-write) | |
130 | */ | |
131 | #define L1_ENTRIES_PER_SECTOR (512 / 8) | |
66f82cee | 132 | static int write_l1_entry(BlockDriverState *bs, int l1_index) |
6583e3c7 | 133 | { |
66f82cee | 134 | BDRVQcowState *s = bs->opaque; |
6583e3c7 KW |
135 | uint64_t buf[L1_ENTRIES_PER_SECTOR]; |
136 | int l1_start_index; | |
f7defcb6 | 137 | int i, ret; |
6583e3c7 KW |
138 | |
139 | l1_start_index = l1_index & ~(L1_ENTRIES_PER_SECTOR - 1); | |
140 | for (i = 0; i < L1_ENTRIES_PER_SECTOR; i++) { | |
141 | buf[i] = cpu_to_be64(s->l1_table[l1_start_index + i]); | |
142 | } | |
143 | ||
66f82cee | 144 | BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); |
8b3b7206 | 145 | ret = bdrv_pwrite_sync(bs->file, s->l1_table_offset + 8 * l1_start_index, |
f7defcb6 KW |
146 | buf, sizeof(buf)); |
147 | if (ret < 0) { | |
148 | return ret; | |
6583e3c7 KW |
149 | } |
150 | ||
151 | return 0; | |
152 | } | |
153 | ||
45aba42f KW |
154 | /* |
155 | * l2_allocate | |
156 | * | |
157 | * Allocate a new l2 entry in the file. If l1_index points to an already | |
158 | * used entry in the L2 table (i.e. we are doing a copy on write for the L2 | |
159 | * table) copy the contents of the old L2 table into the newly allocated one. | |
160 | * Otherwise the new table is initialized with zeros. | |
161 | * | |
162 | */ | |
163 | ||
c46e1167 | 164 | static int l2_allocate(BlockDriverState *bs, int l1_index, uint64_t **table) |
45aba42f KW |
165 | { |
166 | BDRVQcowState *s = bs->opaque; | |
6583e3c7 | 167 | uint64_t old_l2_offset; |
f4f0d391 KW |
168 | uint64_t *l2_table; |
169 | int64_t l2_offset; | |
c46e1167 | 170 | int ret; |
45aba42f KW |
171 | |
172 | old_l2_offset = s->l1_table[l1_index]; | |
173 | ||
3cce16f4 KW |
174 | trace_qcow2_l2_allocate(bs, l1_index); |
175 | ||
45aba42f KW |
176 | /* allocate a new l2 entry */ |
177 | ||
ed6ccf0f | 178 | l2_offset = qcow2_alloc_clusters(bs, s->l2_size * sizeof(uint64_t)); |
5d757b56 | 179 | if (l2_offset < 0) { |
c46e1167 | 180 | return l2_offset; |
5d757b56 | 181 | } |
29c1a730 KW |
182 | |
183 | ret = qcow2_cache_flush(bs, s->refcount_block_cache); | |
184 | if (ret < 0) { | |
185 | goto fail; | |
186 | } | |
45aba42f | 187 | |
45aba42f KW |
188 | /* allocate a new entry in the l2 cache */ |
189 | ||
3cce16f4 | 190 | trace_qcow2_l2_allocate_get_empty(bs, l1_index); |
29c1a730 KW |
191 | ret = qcow2_cache_get_empty(bs, s->l2_table_cache, l2_offset, (void**) table); |
192 | if (ret < 0) { | |
193 | return ret; | |
194 | } | |
195 | ||
196 | l2_table = *table; | |
45aba42f KW |
197 | |
198 | if (old_l2_offset == 0) { | |
199 | /* if there was no old l2 table, clear the new table */ | |
200 | memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); | |
201 | } else { | |
29c1a730 KW |
202 | uint64_t* old_table; |
203 | ||
45aba42f | 204 | /* if there was an old l2 table, read it from the disk */ |
66f82cee | 205 | BLKDBG_EVENT(bs->file, BLKDBG_L2_ALLOC_COW_READ); |
29c1a730 KW |
206 | ret = qcow2_cache_get(bs, s->l2_table_cache, old_l2_offset, |
207 | (void**) &old_table); | |
208 | if (ret < 0) { | |
209 | goto fail; | |
210 | } | |
211 | ||
212 | memcpy(l2_table, old_table, s->cluster_size); | |
213 | ||
214 | ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &old_table); | |
c46e1167 | 215 | if (ret < 0) { |
175e1152 | 216 | goto fail; |
c46e1167 | 217 | } |
45aba42f | 218 | } |
29c1a730 | 219 | |
45aba42f | 220 | /* write the l2 table to the file */ |
66f82cee | 221 | BLKDBG_EVENT(bs->file, BLKDBG_L2_ALLOC_WRITE); |
29c1a730 | 222 | |
3cce16f4 | 223 | trace_qcow2_l2_allocate_write_l2(bs, l1_index); |
29c1a730 KW |
224 | qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table); |
225 | ret = qcow2_cache_flush(bs, s->l2_table_cache); | |
c46e1167 | 226 | if (ret < 0) { |
175e1152 KW |
227 | goto fail; |
228 | } | |
229 | ||
230 | /* update the L1 entry */ | |
3cce16f4 | 231 | trace_qcow2_l2_allocate_write_l1(bs, l1_index); |
175e1152 KW |
232 | s->l1_table[l1_index] = l2_offset | QCOW_OFLAG_COPIED; |
233 | ret = write_l1_entry(bs, l1_index); | |
234 | if (ret < 0) { | |
235 | goto fail; | |
c46e1167 | 236 | } |
45aba42f | 237 | |
c46e1167 | 238 | *table = l2_table; |
3cce16f4 | 239 | trace_qcow2_l2_allocate_done(bs, l1_index, 0); |
c46e1167 | 240 | return 0; |
175e1152 KW |
241 | |
242 | fail: | |
3cce16f4 | 243 | trace_qcow2_l2_allocate_done(bs, l1_index, ret); |
29c1a730 | 244 | qcow2_cache_put(bs, s->l2_table_cache, (void**) table); |
68dba0bf | 245 | s->l1_table[l1_index] = old_l2_offset; |
175e1152 | 246 | return ret; |
45aba42f KW |
247 | } |
248 | ||
249 | static int count_contiguous_clusters(uint64_t nb_clusters, int cluster_size, | |
250 | uint64_t *l2_table, uint64_t start, uint64_t mask) | |
251 | { | |
252 | int i; | |
253 | uint64_t offset = be64_to_cpu(l2_table[0]) & ~mask; | |
254 | ||
255 | if (!offset) | |
256 | return 0; | |
257 | ||
258 | for (i = start; i < start + nb_clusters; i++) | |
80ee15a6 | 259 | if (offset + (uint64_t) i * cluster_size != (be64_to_cpu(l2_table[i]) & ~mask)) |
45aba42f KW |
260 | break; |
261 | ||
262 | return (i - start); | |
263 | } | |
264 | ||
265 | static int count_contiguous_free_clusters(uint64_t nb_clusters, uint64_t *l2_table) | |
266 | { | |
267 | int i = 0; | |
268 | ||
269 | while(nb_clusters-- && l2_table[i] == 0) | |
270 | i++; | |
271 | ||
272 | return i; | |
273 | } | |
274 | ||
275 | /* The crypt function is compatible with the linux cryptoloop | |
276 | algorithm for < 4 GB images. NOTE: out_buf == in_buf is | |
277 | supported */ | |
ed6ccf0f KW |
278 | void qcow2_encrypt_sectors(BDRVQcowState *s, int64_t sector_num, |
279 | uint8_t *out_buf, const uint8_t *in_buf, | |
280 | int nb_sectors, int enc, | |
281 | const AES_KEY *key) | |
45aba42f KW |
282 | { |
283 | union { | |
284 | uint64_t ll[2]; | |
285 | uint8_t b[16]; | |
286 | } ivec; | |
287 | int i; | |
288 | ||
289 | for(i = 0; i < nb_sectors; i++) { | |
290 | ivec.ll[0] = cpu_to_le64(sector_num); | |
291 | ivec.ll[1] = 0; | |
292 | AES_cbc_encrypt(in_buf, out_buf, 512, key, | |
293 | ivec.b, enc); | |
294 | sector_num++; | |
295 | in_buf += 512; | |
296 | out_buf += 512; | |
297 | } | |
298 | } | |
299 | ||
aef4acb6 SH |
300 | static int coroutine_fn copy_sectors(BlockDriverState *bs, |
301 | uint64_t start_sect, | |
302 | uint64_t cluster_offset, | |
303 | int n_start, int n_end) | |
45aba42f KW |
304 | { |
305 | BDRVQcowState *s = bs->opaque; | |
aef4acb6 SH |
306 | QEMUIOVector qiov; |
307 | struct iovec iov; | |
45aba42f | 308 | int n, ret; |
1b9f1491 KW |
309 | |
310 | /* | |
311 | * If this is the last cluster and it is only partially used, we must only | |
312 | * copy until the end of the image, or bdrv_check_request will fail for the | |
313 | * bdrv_read/write calls below. | |
314 | */ | |
315 | if (start_sect + n_end > bs->total_sectors) { | |
316 | n_end = bs->total_sectors - start_sect; | |
317 | } | |
45aba42f KW |
318 | |
319 | n = n_end - n_start; | |
1b9f1491 | 320 | if (n <= 0) { |
45aba42f | 321 | return 0; |
1b9f1491 KW |
322 | } |
323 | ||
aef4acb6 SH |
324 | iov.iov_len = n * BDRV_SECTOR_SIZE; |
325 | iov.iov_base = qemu_blockalign(bs, iov.iov_len); | |
326 | ||
327 | qemu_iovec_init_external(&qiov, &iov, 1); | |
1b9f1491 | 328 | |
66f82cee | 329 | BLKDBG_EVENT(bs->file, BLKDBG_COW_READ); |
aef4acb6 SH |
330 | |
331 | /* Call .bdrv_co_readv() directly instead of using the public block-layer | |
332 | * interface. This avoids double I/O throttling and request tracking, | |
333 | * which can lead to deadlock when block layer copy-on-read is enabled. | |
334 | */ | |
335 | ret = bs->drv->bdrv_co_readv(bs, start_sect + n_start, n, &qiov); | |
1b9f1491 KW |
336 | if (ret < 0) { |
337 | goto out; | |
338 | } | |
339 | ||
45aba42f | 340 | if (s->crypt_method) { |
ed6ccf0f | 341 | qcow2_encrypt_sectors(s, start_sect + n_start, |
aef4acb6 | 342 | iov.iov_base, iov.iov_base, n, 1, |
45aba42f KW |
343 | &s->aes_encrypt_key); |
344 | } | |
1b9f1491 | 345 | |
66f82cee | 346 | BLKDBG_EVENT(bs->file, BLKDBG_COW_WRITE); |
aef4acb6 | 347 | ret = bdrv_co_writev(bs->file, (cluster_offset >> 9) + n_start, n, &qiov); |
1b9f1491 KW |
348 | if (ret < 0) { |
349 | goto out; | |
350 | } | |
351 | ||
352 | ret = 0; | |
353 | out: | |
aef4acb6 | 354 | qemu_vfree(iov.iov_base); |
1b9f1491 | 355 | return ret; |
45aba42f KW |
356 | } |
357 | ||
358 | ||
359 | /* | |
360 | * get_cluster_offset | |
361 | * | |
1c46efaa KW |
362 | * For a given offset of the disk image, find the cluster offset in |
363 | * qcow2 file. The offset is stored in *cluster_offset. | |
45aba42f | 364 | * |
d57237f2 | 365 | * on entry, *num is the number of contiguous sectors we'd like to |
45aba42f KW |
366 | * access following offset. |
367 | * | |
d57237f2 | 368 | * on exit, *num is the number of contiguous sectors we can read. |
45aba42f | 369 | * |
1c46efaa KW |
370 | * Return 0, if the offset is found |
371 | * Return -errno, otherwise. | |
45aba42f KW |
372 | * |
373 | */ | |
374 | ||
1c46efaa KW |
375 | int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset, |
376 | int *num, uint64_t *cluster_offset) | |
45aba42f KW |
377 | { |
378 | BDRVQcowState *s = bs->opaque; | |
80ee15a6 | 379 | unsigned int l1_index, l2_index; |
1c46efaa | 380 | uint64_t l2_offset, *l2_table; |
45aba42f | 381 | int l1_bits, c; |
80ee15a6 KW |
382 | unsigned int index_in_cluster, nb_clusters; |
383 | uint64_t nb_available, nb_needed; | |
55c17e98 | 384 | int ret; |
45aba42f KW |
385 | |
386 | index_in_cluster = (offset >> 9) & (s->cluster_sectors - 1); | |
387 | nb_needed = *num + index_in_cluster; | |
388 | ||
389 | l1_bits = s->l2_bits + s->cluster_bits; | |
390 | ||
391 | /* compute how many bytes there are between the offset and | |
392 | * the end of the l1 entry | |
393 | */ | |
394 | ||
80ee15a6 | 395 | nb_available = (1ULL << l1_bits) - (offset & ((1ULL << l1_bits) - 1)); |
45aba42f KW |
396 | |
397 | /* compute the number of available sectors */ | |
398 | ||
399 | nb_available = (nb_available >> 9) + index_in_cluster; | |
400 | ||
401 | if (nb_needed > nb_available) { | |
402 | nb_needed = nb_available; | |
403 | } | |
404 | ||
1c46efaa | 405 | *cluster_offset = 0; |
45aba42f KW |
406 | |
407 | /* seek the the l2 offset in the l1 table */ | |
408 | ||
409 | l1_index = offset >> l1_bits; | |
410 | if (l1_index >= s->l1_size) | |
411 | goto out; | |
412 | ||
413 | l2_offset = s->l1_table[l1_index]; | |
414 | ||
415 | /* seek the l2 table of the given l2 offset */ | |
416 | ||
417 | if (!l2_offset) | |
418 | goto out; | |
419 | ||
420 | /* load the l2 table in memory */ | |
421 | ||
422 | l2_offset &= ~QCOW_OFLAG_COPIED; | |
55c17e98 KW |
423 | ret = l2_load(bs, l2_offset, &l2_table); |
424 | if (ret < 0) { | |
425 | return ret; | |
1c46efaa | 426 | } |
45aba42f KW |
427 | |
428 | /* find the cluster offset for the given disk offset */ | |
429 | ||
430 | l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1); | |
1c46efaa | 431 | *cluster_offset = be64_to_cpu(l2_table[l2_index]); |
45aba42f KW |
432 | nb_clusters = size_to_clusters(s, nb_needed << 9); |
433 | ||
1c46efaa | 434 | if (!*cluster_offset) { |
45aba42f KW |
435 | /* how many empty clusters ? */ |
436 | c = count_contiguous_free_clusters(nb_clusters, &l2_table[l2_index]); | |
437 | } else { | |
438 | /* how many allocated clusters ? */ | |
439 | c = count_contiguous_clusters(nb_clusters, s->cluster_size, | |
440 | &l2_table[l2_index], 0, QCOW_OFLAG_COPIED); | |
441 | } | |
442 | ||
29c1a730 KW |
443 | qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); |
444 | ||
45aba42f KW |
445 | nb_available = (c * s->cluster_sectors); |
446 | out: | |
447 | if (nb_available > nb_needed) | |
448 | nb_available = nb_needed; | |
449 | ||
450 | *num = nb_available - index_in_cluster; | |
451 | ||
1c46efaa KW |
452 | *cluster_offset &=~QCOW_OFLAG_COPIED; |
453 | return 0; | |
45aba42f KW |
454 | } |
455 | ||
456 | /* | |
457 | * get_cluster_table | |
458 | * | |
459 | * for a given disk offset, load (and allocate if needed) | |
460 | * the l2 table. | |
461 | * | |
462 | * the l2 table offset in the qcow2 file and the cluster index | |
463 | * in the l2 table are given to the caller. | |
464 | * | |
1e3e8f1a | 465 | * Returns 0 on success, -errno in failure case |
45aba42f | 466 | */ |
45aba42f KW |
467 | static int get_cluster_table(BlockDriverState *bs, uint64_t offset, |
468 | uint64_t **new_l2_table, | |
45aba42f KW |
469 | int *new_l2_index) |
470 | { | |
471 | BDRVQcowState *s = bs->opaque; | |
80ee15a6 | 472 | unsigned int l1_index, l2_index; |
c46e1167 KW |
473 | uint64_t l2_offset; |
474 | uint64_t *l2_table = NULL; | |
80ee15a6 | 475 | int ret; |
45aba42f KW |
476 | |
477 | /* seek the the l2 offset in the l1 table */ | |
478 | ||
479 | l1_index = offset >> (s->l2_bits + s->cluster_bits); | |
480 | if (l1_index >= s->l1_size) { | |
72893756 | 481 | ret = qcow2_grow_l1_table(bs, l1_index + 1, false); |
1e3e8f1a KW |
482 | if (ret < 0) { |
483 | return ret; | |
484 | } | |
45aba42f KW |
485 | } |
486 | l2_offset = s->l1_table[l1_index]; | |
487 | ||
488 | /* seek the l2 table of the given l2 offset */ | |
489 | ||
490 | if (l2_offset & QCOW_OFLAG_COPIED) { | |
491 | /* load the l2 table in memory */ | |
492 | l2_offset &= ~QCOW_OFLAG_COPIED; | |
55c17e98 KW |
493 | ret = l2_load(bs, l2_offset, &l2_table); |
494 | if (ret < 0) { | |
495 | return ret; | |
1e3e8f1a | 496 | } |
45aba42f | 497 | } else { |
16fde5f2 | 498 | /* First allocate a new L2 table (and do COW if needed) */ |
c46e1167 KW |
499 | ret = l2_allocate(bs, l1_index, &l2_table); |
500 | if (ret < 0) { | |
501 | return ret; | |
1e3e8f1a | 502 | } |
16fde5f2 KW |
503 | |
504 | /* Then decrease the refcount of the old table */ | |
505 | if (l2_offset) { | |
506 | qcow2_free_clusters(bs, l2_offset, s->l2_size * sizeof(uint64_t)); | |
507 | } | |
45aba42f KW |
508 | l2_offset = s->l1_table[l1_index] & ~QCOW_OFLAG_COPIED; |
509 | } | |
510 | ||
511 | /* find the cluster offset for the given disk offset */ | |
512 | ||
513 | l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1); | |
514 | ||
515 | *new_l2_table = l2_table; | |
45aba42f KW |
516 | *new_l2_index = l2_index; |
517 | ||
1e3e8f1a | 518 | return 0; |
45aba42f KW |
519 | } |
520 | ||
521 | /* | |
522 | * alloc_compressed_cluster_offset | |
523 | * | |
524 | * For a given offset of the disk image, return cluster offset in | |
525 | * qcow2 file. | |
526 | * | |
527 | * If the offset is not found, allocate a new compressed cluster. | |
528 | * | |
529 | * Return the cluster offset if successful, | |
530 | * Return 0, otherwise. | |
531 | * | |
532 | */ | |
533 | ||
ed6ccf0f KW |
534 | uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs, |
535 | uint64_t offset, | |
536 | int compressed_size) | |
45aba42f KW |
537 | { |
538 | BDRVQcowState *s = bs->opaque; | |
539 | int l2_index, ret; | |
3948d1d4 | 540 | uint64_t *l2_table; |
f4f0d391 | 541 | int64_t cluster_offset; |
45aba42f KW |
542 | int nb_csectors; |
543 | ||
3948d1d4 | 544 | ret = get_cluster_table(bs, offset, &l2_table, &l2_index); |
1e3e8f1a | 545 | if (ret < 0) { |
45aba42f | 546 | return 0; |
1e3e8f1a | 547 | } |
45aba42f KW |
548 | |
549 | cluster_offset = be64_to_cpu(l2_table[l2_index]); | |
8f1efd00 KW |
550 | if (cluster_offset & QCOW_OFLAG_COPIED) { |
551 | qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); | |
552 | return 0; | |
553 | } | |
45aba42f KW |
554 | |
555 | if (cluster_offset) | |
ed6ccf0f | 556 | qcow2_free_any_clusters(bs, cluster_offset, 1); |
45aba42f | 557 | |
ed6ccf0f | 558 | cluster_offset = qcow2_alloc_bytes(bs, compressed_size); |
5d757b56 | 559 | if (cluster_offset < 0) { |
29c1a730 | 560 | qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); |
5d757b56 KW |
561 | return 0; |
562 | } | |
563 | ||
45aba42f KW |
564 | nb_csectors = ((cluster_offset + compressed_size - 1) >> 9) - |
565 | (cluster_offset >> 9); | |
566 | ||
567 | cluster_offset |= QCOW_OFLAG_COMPRESSED | | |
568 | ((uint64_t)nb_csectors << s->csize_shift); | |
569 | ||
570 | /* update L2 table */ | |
571 | ||
572 | /* compressed clusters never have the copied flag */ | |
573 | ||
66f82cee | 574 | BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE_COMPRESSED); |
29c1a730 | 575 | qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table); |
45aba42f | 576 | l2_table[l2_index] = cpu_to_be64(cluster_offset); |
29c1a730 | 577 | ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); |
79a31189 | 578 | if (ret < 0) { |
29c1a730 | 579 | return 0; |
4c1612d9 KW |
580 | } |
581 | ||
29c1a730 | 582 | return cluster_offset; |
4c1612d9 KW |
583 | } |
584 | ||
148da7ea | 585 | int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m) |
45aba42f KW |
586 | { |
587 | BDRVQcowState *s = bs->opaque; | |
588 | int i, j = 0, l2_index, ret; | |
3948d1d4 | 589 | uint64_t *old_cluster, start_sect, *l2_table; |
250196f1 | 590 | uint64_t cluster_offset = m->alloc_offset; |
29c1a730 | 591 | bool cow = false; |
45aba42f | 592 | |
3cce16f4 KW |
593 | trace_qcow2_cluster_link_l2(qemu_coroutine_self(), m->nb_clusters); |
594 | ||
45aba42f KW |
595 | if (m->nb_clusters == 0) |
596 | return 0; | |
597 | ||
7267c094 | 598 | old_cluster = g_malloc(m->nb_clusters * sizeof(uint64_t)); |
45aba42f KW |
599 | |
600 | /* copy content of unmodified sectors */ | |
601 | start_sect = (m->offset & ~(s->cluster_size - 1)) >> 9; | |
602 | if (m->n_start) { | |
29c1a730 | 603 | cow = true; |
1b9f1491 | 604 | qemu_co_mutex_unlock(&s->lock); |
45aba42f | 605 | ret = copy_sectors(bs, start_sect, cluster_offset, 0, m->n_start); |
1b9f1491 | 606 | qemu_co_mutex_lock(&s->lock); |
45aba42f KW |
607 | if (ret < 0) |
608 | goto err; | |
609 | } | |
610 | ||
611 | if (m->nb_available & (s->cluster_sectors - 1)) { | |
612 | uint64_t end = m->nb_available & ~(uint64_t)(s->cluster_sectors - 1); | |
29c1a730 | 613 | cow = true; |
1b9f1491 | 614 | qemu_co_mutex_unlock(&s->lock); |
45aba42f KW |
615 | ret = copy_sectors(bs, start_sect + end, cluster_offset + (end << 9), |
616 | m->nb_available - end, s->cluster_sectors); | |
1b9f1491 | 617 | qemu_co_mutex_lock(&s->lock); |
45aba42f KW |
618 | if (ret < 0) |
619 | goto err; | |
620 | } | |
621 | ||
29c1a730 KW |
622 | /* |
623 | * Update L2 table. | |
624 | * | |
625 | * Before we update the L2 table to actually point to the new cluster, we | |
626 | * need to be sure that the refcounts have been increased and COW was | |
627 | * handled. | |
628 | */ | |
629 | if (cow) { | |
3de0a294 | 630 | qcow2_cache_depends_on_flush(s->l2_table_cache); |
29c1a730 KW |
631 | } |
632 | ||
633 | qcow2_cache_set_dependency(bs, s->l2_table_cache, s->refcount_block_cache); | |
3948d1d4 | 634 | ret = get_cluster_table(bs, m->offset, &l2_table, &l2_index); |
1e3e8f1a | 635 | if (ret < 0) { |
45aba42f | 636 | goto err; |
1e3e8f1a | 637 | } |
29c1a730 | 638 | qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table); |
45aba42f KW |
639 | |
640 | for (i = 0; i < m->nb_clusters; i++) { | |
641 | /* if two concurrent writes happen to the same unallocated cluster | |
642 | * each write allocates separate cluster and writes data concurrently. | |
643 | * The first one to complete updates l2 table with pointer to its | |
644 | * cluster the second one has to do RMW (which is done above by | |
645 | * copy_sectors()), update l2 table with its cluster pointer and free | |
646 | * old cluster. This is what this loop does */ | |
647 | if(l2_table[l2_index + i] != 0) | |
648 | old_cluster[j++] = l2_table[l2_index + i]; | |
649 | ||
650 | l2_table[l2_index + i] = cpu_to_be64((cluster_offset + | |
651 | (i << s->cluster_bits)) | QCOW_OFLAG_COPIED); | |
652 | } | |
653 | ||
9f8e668e | 654 | |
29c1a730 | 655 | ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); |
c835d00f | 656 | if (ret < 0) { |
45aba42f | 657 | goto err; |
4c1612d9 | 658 | } |
45aba42f | 659 | |
7ec5e6a4 KW |
660 | /* |
661 | * If this was a COW, we need to decrease the refcount of the old cluster. | |
662 | * Also flush bs->file to get the right order for L2 and refcount update. | |
663 | */ | |
664 | if (j != 0) { | |
7ec5e6a4 KW |
665 | for (i = 0; i < j; i++) { |
666 | qcow2_free_any_clusters(bs, | |
667 | be64_to_cpu(old_cluster[i]) & ~QCOW_OFLAG_COPIED, 1); | |
668 | } | |
669 | } | |
45aba42f KW |
670 | |
671 | ret = 0; | |
672 | err: | |
7267c094 | 673 | g_free(old_cluster); |
45aba42f KW |
674 | return ret; |
675 | } | |
676 | ||
bf319ece KW |
677 | /* |
678 | * Returns the number of contiguous clusters that can be used for an allocating | |
679 | * write, but require COW to be performed (this includes yet unallocated space, | |
680 | * which must copy from the backing file) | |
681 | */ | |
682 | static int count_cow_clusters(BDRVQcowState *s, int nb_clusters, | |
683 | uint64_t *l2_table, int l2_index) | |
684 | { | |
685 | int i = 0; | |
686 | uint64_t cluster_offset; | |
687 | ||
688 | while (i < nb_clusters) { | |
689 | i += count_contiguous_clusters(nb_clusters - i, s->cluster_size, | |
690 | &l2_table[l2_index], i, 0); | |
691 | if ((i >= nb_clusters) || be64_to_cpu(l2_table[l2_index + i])) { | |
692 | break; | |
693 | } | |
694 | ||
695 | i += count_contiguous_free_clusters(nb_clusters - i, | |
696 | &l2_table[l2_index + i]); | |
697 | if (i >= nb_clusters) { | |
698 | break; | |
699 | } | |
700 | ||
701 | cluster_offset = be64_to_cpu(l2_table[l2_index + i]); | |
702 | ||
703 | if ((cluster_offset & QCOW_OFLAG_COPIED) || | |
704 | (cluster_offset & QCOW_OFLAG_COMPRESSED)) | |
705 | break; | |
706 | } | |
707 | ||
708 | assert(i <= nb_clusters); | |
709 | return i; | |
710 | } | |
711 | ||
250196f1 KW |
712 | /* |
713 | * Allocates new clusters for the given guest_offset. | |
714 | * | |
715 | * At most *nb_clusters are allocated, and on return *nb_clusters is updated to | |
716 | * contain the number of clusters that have been allocated and are contiguous | |
717 | * in the image file. | |
718 | * | |
719 | * If *host_offset is non-zero, it specifies the offset in the image file at | |
720 | * which the new clusters must start. *nb_clusters can be 0 on return in this | |
721 | * case if the cluster at host_offset is already in use. If *host_offset is | |
722 | * zero, the clusters can be allocated anywhere in the image file. | |
723 | * | |
724 | * *host_offset is updated to contain the offset into the image file at which | |
725 | * the first allocated cluster starts. | |
726 | * | |
727 | * Return 0 on success and -errno in error cases. -EAGAIN means that the | |
728 | * function has been waiting for another request and the allocation must be | |
729 | * restarted, but the whole request should not be failed. | |
730 | */ | |
731 | static int do_alloc_cluster_offset(BlockDriverState *bs, uint64_t guest_offset, | |
732 | uint64_t *host_offset, unsigned int *nb_clusters, uint64_t *l2_table) | |
733 | { | |
734 | BDRVQcowState *s = bs->opaque; | |
735 | int64_t cluster_offset; | |
736 | QCowL2Meta *old_alloc; | |
737 | ||
738 | trace_qcow2_do_alloc_clusters_offset(qemu_coroutine_self(), guest_offset, | |
739 | *host_offset, *nb_clusters); | |
740 | ||
741 | /* | |
742 | * Check if there already is an AIO write request in flight which allocates | |
743 | * the same cluster. In this case we need to wait until the previous | |
744 | * request has completed and updated the L2 table accordingly. | |
745 | */ | |
746 | QLIST_FOREACH(old_alloc, &s->cluster_allocs, next_in_flight) { | |
747 | ||
748 | uint64_t start = guest_offset >> s->cluster_bits; | |
749 | uint64_t end = start + *nb_clusters; | |
750 | uint64_t old_start = old_alloc->offset >> s->cluster_bits; | |
751 | uint64_t old_end = old_start + old_alloc->nb_clusters; | |
752 | ||
753 | if (end < old_start || start > old_end) { | |
754 | /* No intersection */ | |
755 | } else { | |
756 | if (start < old_start) { | |
757 | /* Stop at the start of a running allocation */ | |
758 | *nb_clusters = old_start - start; | |
759 | } else { | |
760 | *nb_clusters = 0; | |
761 | } | |
762 | ||
763 | if (*nb_clusters == 0) { | |
764 | /* Wait for the dependency to complete. We need to recheck | |
765 | * the free/allocated clusters when we continue. */ | |
766 | qemu_co_mutex_unlock(&s->lock); | |
767 | qemu_co_queue_wait(&old_alloc->dependent_requests); | |
768 | qemu_co_mutex_lock(&s->lock); | |
769 | return -EAGAIN; | |
770 | } | |
771 | } | |
772 | } | |
773 | ||
774 | if (!*nb_clusters) { | |
775 | abort(); | |
776 | } | |
777 | ||
778 | /* Allocate new clusters */ | |
779 | trace_qcow2_cluster_alloc_phys(qemu_coroutine_self()); | |
780 | if (*host_offset == 0) { | |
781 | cluster_offset = qcow2_alloc_clusters(bs, *nb_clusters * s->cluster_size); | |
782 | } else { | |
783 | cluster_offset = *host_offset; | |
784 | *nb_clusters = qcow2_alloc_clusters_at(bs, cluster_offset, *nb_clusters); | |
785 | } | |
786 | ||
787 | if (cluster_offset < 0) { | |
788 | return cluster_offset; | |
789 | } | |
790 | *host_offset = cluster_offset; | |
791 | return 0; | |
792 | } | |
793 | ||
45aba42f KW |
794 | /* |
795 | * alloc_cluster_offset | |
796 | * | |
250196f1 KW |
797 | * For a given offset on the virtual disk, find the cluster offset in qcow2 |
798 | * file. If the offset is not found, allocate a new cluster. | |
45aba42f | 799 | * |
250196f1 | 800 | * If the cluster was already allocated, m->nb_clusters is set to 0 and |
a7912369 | 801 | * other fields in m are meaningless. |
148da7ea KW |
802 | * |
803 | * If the cluster is newly allocated, m->nb_clusters is set to the number of | |
68d100e9 KW |
804 | * contiguous clusters that have been allocated. In this case, the other |
805 | * fields of m are valid and contain information about the first allocated | |
806 | * cluster. | |
45aba42f | 807 | * |
68d100e9 KW |
808 | * If the request conflicts with another write request in flight, the coroutine |
809 | * is queued and will be reentered when the dependency has completed. | |
148da7ea KW |
810 | * |
811 | * Return 0 on success and -errno in error cases | |
45aba42f | 812 | */ |
f4f0d391 KW |
813 | int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset, |
814 | int n_start, int n_end, int *num, QCowL2Meta *m) | |
45aba42f KW |
815 | { |
816 | BDRVQcowState *s = bs->opaque; | |
250196f1 | 817 | int l2_index, ret, sectors; |
3948d1d4 | 818 | uint64_t *l2_table; |
250196f1 KW |
819 | unsigned int nb_clusters, keep_clusters; |
820 | uint64_t cluster_offset; | |
45aba42f | 821 | |
3cce16f4 KW |
822 | trace_qcow2_alloc_clusters_offset(qemu_coroutine_self(), offset, |
823 | n_start, n_end); | |
824 | ||
250196f1 | 825 | /* Find L2 entry for the first involved cluster */ |
3948d1d4 | 826 | ret = get_cluster_table(bs, offset, &l2_table, &l2_index); |
1e3e8f1a | 827 | if (ret < 0) { |
148da7ea | 828 | return ret; |
1e3e8f1a | 829 | } |
45aba42f | 830 | |
250196f1 KW |
831 | /* |
832 | * Calculate the number of clusters to look for. We stop at L2 table | |
833 | * boundaries to keep things simple. | |
834 | */ | |
68d100e9 | 835 | again: |
250196f1 KW |
836 | nb_clusters = MIN(size_to_clusters(s, n_end << BDRV_SECTOR_BITS), |
837 | s->l2_size - l2_index); | |
45aba42f KW |
838 | |
839 | cluster_offset = be64_to_cpu(l2_table[l2_index]); | |
840 | ||
250196f1 KW |
841 | /* |
842 | * Check how many clusters are already allocated and don't need COW, and how | |
843 | * many need a new allocation. | |
844 | */ | |
45aba42f | 845 | if (cluster_offset & QCOW_OFLAG_COPIED) { |
250196f1 KW |
846 | /* We keep all QCOW_OFLAG_COPIED clusters */ |
847 | keep_clusters = count_contiguous_clusters(nb_clusters, s->cluster_size, | |
848 | &l2_table[l2_index], 0, 0); | |
849 | assert(keep_clusters <= nb_clusters); | |
850 | nb_clusters -= keep_clusters; | |
851 | } else { | |
852 | /* For the moment, overwrite compressed clusters one by one */ | |
853 | if (cluster_offset & QCOW_OFLAG_COMPRESSED) { | |
854 | nb_clusters = 1; | |
855 | } else { | |
856 | nb_clusters = count_cow_clusters(s, nb_clusters, l2_table, l2_index); | |
857 | } | |
45aba42f | 858 | |
250196f1 KW |
859 | keep_clusters = 0; |
860 | cluster_offset = 0; | |
45aba42f KW |
861 | } |
862 | ||
250196f1 | 863 | cluster_offset &= ~QCOW_OFLAG_COPIED; |
45aba42f | 864 | |
250196f1 KW |
865 | /* If there is something left to allocate, do that now */ |
866 | *m = (QCowL2Meta) { | |
867 | .cluster_offset = cluster_offset, | |
868 | .nb_clusters = 0, | |
869 | }; | |
870 | qemu_co_queue_init(&m->dependent_requests); | |
45aba42f | 871 | |
250196f1 KW |
872 | if (nb_clusters > 0) { |
873 | uint64_t alloc_offset; | |
874 | uint64_t alloc_cluster_offset; | |
875 | uint64_t keep_bytes = keep_clusters * s->cluster_size; | |
45aba42f | 876 | |
250196f1 KW |
877 | /* Calculate start and size of allocation */ |
878 | alloc_offset = offset + keep_bytes; | |
45aba42f | 879 | |
250196f1 KW |
880 | if (keep_clusters == 0) { |
881 | alloc_cluster_offset = 0; | |
f214978a | 882 | } else { |
250196f1 | 883 | alloc_cluster_offset = cluster_offset + keep_bytes; |
f214978a | 884 | } |
f214978a | 885 | |
250196f1 KW |
886 | /* Allocate, if necessary at a given offset in the image file */ |
887 | ret = do_alloc_cluster_offset(bs, alloc_offset, &alloc_cluster_offset, | |
888 | &nb_clusters, l2_table); | |
889 | if (ret == -EAGAIN) { | |
890 | goto again; | |
891 | } else if (ret < 0) { | |
892 | goto fail; | |
893 | } | |
f214978a | 894 | |
250196f1 KW |
895 | /* save info needed for meta data update */ |
896 | if (nb_clusters > 0) { | |
897 | int requested_sectors = n_end - keep_clusters * s->cluster_sectors; | |
898 | int avail_sectors = (keep_clusters + nb_clusters) | |
899 | << (s->cluster_bits - BDRV_SECTOR_BITS); | |
900 | ||
901 | *m = (QCowL2Meta) { | |
902 | .cluster_offset = keep_clusters == 0 ? | |
903 | alloc_cluster_offset : cluster_offset, | |
904 | .alloc_offset = alloc_cluster_offset, | |
905 | .offset = alloc_offset, | |
906 | .n_start = keep_clusters == 0 ? n_start : 0, | |
907 | .nb_clusters = nb_clusters, | |
908 | .nb_available = MIN(requested_sectors, avail_sectors), | |
909 | }; | |
910 | qemu_co_queue_init(&m->dependent_requests); | |
911 | QLIST_INSERT_HEAD(&s->cluster_allocs, m, next_in_flight); | |
912 | } | |
5d757b56 | 913 | } |
45aba42f | 914 | |
250196f1 | 915 | /* Some cleanup work */ |
29c1a730 KW |
916 | ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); |
917 | if (ret < 0) { | |
9e2a3701 | 918 | goto fail_put; |
29c1a730 KW |
919 | } |
920 | ||
250196f1 KW |
921 | sectors = (keep_clusters + nb_clusters) << (s->cluster_bits - 9); |
922 | if (sectors > n_end) { | |
923 | sectors = n_end; | |
924 | } | |
45aba42f | 925 | |
250196f1 KW |
926 | assert(sectors > n_start); |
927 | *num = sectors - n_start; | |
45aba42f | 928 | |
148da7ea | 929 | return 0; |
29c1a730 KW |
930 | |
931 | fail: | |
932 | qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); | |
9e2a3701 | 933 | fail_put: |
8dc0a5e7 | 934 | if (m->nb_clusters > 0) { |
250196f1 KW |
935 | QLIST_REMOVE(m, next_in_flight); |
936 | } | |
29c1a730 | 937 | return ret; |
45aba42f KW |
938 | } |
939 | ||
940 | static int decompress_buffer(uint8_t *out_buf, int out_buf_size, | |
941 | const uint8_t *buf, int buf_size) | |
942 | { | |
943 | z_stream strm1, *strm = &strm1; | |
944 | int ret, out_len; | |
945 | ||
946 | memset(strm, 0, sizeof(*strm)); | |
947 | ||
948 | strm->next_in = (uint8_t *)buf; | |
949 | strm->avail_in = buf_size; | |
950 | strm->next_out = out_buf; | |
951 | strm->avail_out = out_buf_size; | |
952 | ||
953 | ret = inflateInit2(strm, -12); | |
954 | if (ret != Z_OK) | |
955 | return -1; | |
956 | ret = inflate(strm, Z_FINISH); | |
957 | out_len = strm->next_out - out_buf; | |
958 | if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || | |
959 | out_len != out_buf_size) { | |
960 | inflateEnd(strm); | |
961 | return -1; | |
962 | } | |
963 | inflateEnd(strm); | |
964 | return 0; | |
965 | } | |
966 | ||
66f82cee | 967 | int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset) |
45aba42f | 968 | { |
66f82cee | 969 | BDRVQcowState *s = bs->opaque; |
45aba42f KW |
970 | int ret, csize, nb_csectors, sector_offset; |
971 | uint64_t coffset; | |
972 | ||
973 | coffset = cluster_offset & s->cluster_offset_mask; | |
974 | if (s->cluster_cache_offset != coffset) { | |
975 | nb_csectors = ((cluster_offset >> s->csize_shift) & s->csize_mask) + 1; | |
976 | sector_offset = coffset & 511; | |
977 | csize = nb_csectors * 512 - sector_offset; | |
66f82cee KW |
978 | BLKDBG_EVENT(bs->file, BLKDBG_READ_COMPRESSED); |
979 | ret = bdrv_read(bs->file, coffset >> 9, s->cluster_data, nb_csectors); | |
45aba42f | 980 | if (ret < 0) { |
8af36488 | 981 | return ret; |
45aba42f KW |
982 | } |
983 | if (decompress_buffer(s->cluster_cache, s->cluster_size, | |
984 | s->cluster_data + sector_offset, csize) < 0) { | |
8af36488 | 985 | return -EIO; |
45aba42f KW |
986 | } |
987 | s->cluster_cache_offset = coffset; | |
988 | } | |
989 | return 0; | |
990 | } | |
5ea929e3 KW |
991 | |
992 | /* | |
993 | * This discards as many clusters of nb_clusters as possible at once (i.e. | |
994 | * all clusters in the same L2 table) and returns the number of discarded | |
995 | * clusters. | |
996 | */ | |
997 | static int discard_single_l2(BlockDriverState *bs, uint64_t offset, | |
998 | unsigned int nb_clusters) | |
999 | { | |
1000 | BDRVQcowState *s = bs->opaque; | |
3948d1d4 | 1001 | uint64_t *l2_table; |
5ea929e3 KW |
1002 | int l2_index; |
1003 | int ret; | |
1004 | int i; | |
1005 | ||
3948d1d4 | 1006 | ret = get_cluster_table(bs, offset, &l2_table, &l2_index); |
5ea929e3 KW |
1007 | if (ret < 0) { |
1008 | return ret; | |
1009 | } | |
1010 | ||
1011 | /* Limit nb_clusters to one L2 table */ | |
1012 | nb_clusters = MIN(nb_clusters, s->l2_size - l2_index); | |
1013 | ||
1014 | for (i = 0; i < nb_clusters; i++) { | |
1015 | uint64_t old_offset; | |
1016 | ||
1017 | old_offset = be64_to_cpu(l2_table[l2_index + i]); | |
1018 | old_offset &= ~QCOW_OFLAG_COPIED; | |
1019 | ||
1020 | if (old_offset == 0) { | |
1021 | continue; | |
1022 | } | |
1023 | ||
1024 | /* First remove L2 entries */ | |
1025 | qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table); | |
1026 | l2_table[l2_index + i] = cpu_to_be64(0); | |
1027 | ||
1028 | /* Then decrease the refcount */ | |
1029 | qcow2_free_any_clusters(bs, old_offset, 1); | |
1030 | } | |
1031 | ||
1032 | ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); | |
1033 | if (ret < 0) { | |
1034 | return ret; | |
1035 | } | |
1036 | ||
1037 | return nb_clusters; | |
1038 | } | |
1039 | ||
1040 | int qcow2_discard_clusters(BlockDriverState *bs, uint64_t offset, | |
1041 | int nb_sectors) | |
1042 | { | |
1043 | BDRVQcowState *s = bs->opaque; | |
1044 | uint64_t end_offset; | |
1045 | unsigned int nb_clusters; | |
1046 | int ret; | |
1047 | ||
1048 | end_offset = offset + (nb_sectors << BDRV_SECTOR_BITS); | |
1049 | ||
1050 | /* Round start up and end down */ | |
1051 | offset = align_offset(offset, s->cluster_size); | |
1052 | end_offset &= ~(s->cluster_size - 1); | |
1053 | ||
1054 | if (offset > end_offset) { | |
1055 | return 0; | |
1056 | } | |
1057 | ||
1058 | nb_clusters = size_to_clusters(s, end_offset - offset); | |
1059 | ||
1060 | /* Each L2 table is handled by its own loop iteration */ | |
1061 | while (nb_clusters > 0) { | |
1062 | ret = discard_single_l2(bs, offset, nb_clusters); | |
1063 | if (ret < 0) { | |
1064 | return ret; | |
1065 | } | |
1066 | ||
1067 | nb_clusters -= ret; | |
1068 | offset += (ret * s->cluster_size); | |
1069 | } | |
1070 | ||
1071 | return 0; | |
1072 | } |