]>
Commit | Line | Data |
---|---|---|
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" | |
737e150e | 28 | #include "block/block_int.h" |
45aba42f | 29 | #include "block/qcow2.h" |
3cce16f4 | 30 | #include "trace.h" |
45aba42f | 31 | |
2cf7cfa1 KW |
32 | int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size, |
33 | bool exact_size) | |
45aba42f KW |
34 | { |
35 | BDRVQcowState *s = bs->opaque; | |
2cf7cfa1 | 36 | int new_l1_size2, ret, i; |
45aba42f | 37 | uint64_t *new_l1_table; |
fda74f82 | 38 | int64_t old_l1_table_offset, old_l1_size; |
2cf7cfa1 | 39 | int64_t new_l1_table_offset, new_l1_size; |
45aba42f KW |
40 | uint8_t data[12]; |
41 | ||
72893756 | 42 | if (min_size <= s->l1_size) |
45aba42f | 43 | return 0; |
72893756 | 44 | |
b93f9950 HR |
45 | /* Do a sanity check on min_size before trying to calculate new_l1_size |
46 | * (this prevents overflows during the while loop for the calculation of | |
47 | * new_l1_size) */ | |
48 | if (min_size > INT_MAX / sizeof(uint64_t)) { | |
49 | return -EFBIG; | |
50 | } | |
51 | ||
72893756 SH |
52 | if (exact_size) { |
53 | new_l1_size = min_size; | |
54 | } else { | |
55 | /* Bump size up to reduce the number of times we have to grow */ | |
56 | new_l1_size = s->l1_size; | |
57 | if (new_l1_size == 0) { | |
58 | new_l1_size = 1; | |
59 | } | |
60 | while (min_size > new_l1_size) { | |
61 | new_l1_size = (new_l1_size * 3 + 1) / 2; | |
62 | } | |
45aba42f | 63 | } |
72893756 | 64 | |
cab60de9 | 65 | if (new_l1_size > INT_MAX / sizeof(uint64_t)) { |
2cf7cfa1 KW |
66 | return -EFBIG; |
67 | } | |
68 | ||
45aba42f | 69 | #ifdef DEBUG_ALLOC2 |
2cf7cfa1 KW |
70 | fprintf(stderr, "grow l1_table from %d to %" PRId64 "\n", |
71 | s->l1_size, new_l1_size); | |
45aba42f KW |
72 | #endif |
73 | ||
74 | new_l1_size2 = sizeof(uint64_t) * new_l1_size; | |
7267c094 | 75 | new_l1_table = g_malloc0(align_offset(new_l1_size2, 512)); |
45aba42f KW |
76 | memcpy(new_l1_table, s->l1_table, s->l1_size * sizeof(uint64_t)); |
77 | ||
78 | /* write new table (align to cluster) */ | |
66f82cee | 79 | BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_ALLOC_TABLE); |
ed6ccf0f | 80 | new_l1_table_offset = qcow2_alloc_clusters(bs, new_l1_size2); |
5d757b56 | 81 | if (new_l1_table_offset < 0) { |
7267c094 | 82 | g_free(new_l1_table); |
5d757b56 KW |
83 | return new_l1_table_offset; |
84 | } | |
29c1a730 KW |
85 | |
86 | ret = qcow2_cache_flush(bs, s->refcount_block_cache); | |
87 | if (ret < 0) { | |
80fa3341 | 88 | goto fail; |
29c1a730 | 89 | } |
45aba42f | 90 | |
cf93980e HR |
91 | /* the L1 position has not yet been updated, so these clusters must |
92 | * indeed be completely free */ | |
231bb267 HR |
93 | ret = qcow2_pre_write_overlap_check(bs, 0, new_l1_table_offset, |
94 | new_l1_size2); | |
cf93980e HR |
95 | if (ret < 0) { |
96 | goto fail; | |
97 | } | |
98 | ||
66f82cee | 99 | BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_WRITE_TABLE); |
45aba42f KW |
100 | for(i = 0; i < s->l1_size; i++) |
101 | new_l1_table[i] = cpu_to_be64(new_l1_table[i]); | |
8b3b7206 KW |
102 | ret = bdrv_pwrite_sync(bs->file, new_l1_table_offset, new_l1_table, new_l1_size2); |
103 | if (ret < 0) | |
45aba42f KW |
104 | goto fail; |
105 | for(i = 0; i < s->l1_size; i++) | |
106 | new_l1_table[i] = be64_to_cpu(new_l1_table[i]); | |
107 | ||
108 | /* set new table */ | |
66f82cee | 109 | BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_ACTIVATE_TABLE); |
45aba42f | 110 | cpu_to_be32w((uint32_t*)data, new_l1_size); |
e4ef9f46 | 111 | stq_be_p(data + 4, new_l1_table_offset); |
8b3b7206 KW |
112 | ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, l1_size), data,sizeof(data)); |
113 | if (ret < 0) { | |
45aba42f | 114 | goto fail; |
fb8fa77c | 115 | } |
7267c094 | 116 | g_free(s->l1_table); |
fda74f82 | 117 | old_l1_table_offset = s->l1_table_offset; |
45aba42f KW |
118 | s->l1_table_offset = new_l1_table_offset; |
119 | s->l1_table = new_l1_table; | |
fda74f82 | 120 | old_l1_size = s->l1_size; |
45aba42f | 121 | s->l1_size = new_l1_size; |
fda74f82 HR |
122 | qcow2_free_clusters(bs, old_l1_table_offset, old_l1_size * sizeof(uint64_t), |
123 | QCOW2_DISCARD_OTHER); | |
45aba42f KW |
124 | return 0; |
125 | fail: | |
7267c094 | 126 | g_free(new_l1_table); |
6cfcb9b8 KW |
127 | qcow2_free_clusters(bs, new_l1_table_offset, new_l1_size2, |
128 | QCOW2_DISCARD_OTHER); | |
8b3b7206 | 129 | return ret; |
45aba42f KW |
130 | } |
131 | ||
45aba42f KW |
132 | /* |
133 | * l2_load | |
134 | * | |
135 | * Loads a L2 table into memory. If the table is in the cache, the cache | |
136 | * is used; otherwise the L2 table is loaded from the image file. | |
137 | * | |
138 | * Returns a pointer to the L2 table on success, or NULL if the read from | |
139 | * the image file failed. | |
140 | */ | |
141 | ||
55c17e98 KW |
142 | static int l2_load(BlockDriverState *bs, uint64_t l2_offset, |
143 | uint64_t **l2_table) | |
45aba42f KW |
144 | { |
145 | BDRVQcowState *s = bs->opaque; | |
55c17e98 | 146 | int ret; |
45aba42f | 147 | |
29c1a730 | 148 | ret = qcow2_cache_get(bs, s->l2_table_cache, l2_offset, (void**) l2_table); |
45aba42f | 149 | |
29c1a730 | 150 | return ret; |
45aba42f KW |
151 | } |
152 | ||
6583e3c7 KW |
153 | /* |
154 | * Writes one sector of the L1 table to the disk (can't update single entries | |
155 | * and we really don't want bdrv_pread to perform a read-modify-write) | |
156 | */ | |
157 | #define L1_ENTRIES_PER_SECTOR (512 / 8) | |
e23e400e | 158 | int qcow2_write_l1_entry(BlockDriverState *bs, int l1_index) |
6583e3c7 | 159 | { |
66f82cee | 160 | BDRVQcowState *s = bs->opaque; |
6583e3c7 KW |
161 | uint64_t buf[L1_ENTRIES_PER_SECTOR]; |
162 | int l1_start_index; | |
f7defcb6 | 163 | int i, ret; |
6583e3c7 KW |
164 | |
165 | l1_start_index = l1_index & ~(L1_ENTRIES_PER_SECTOR - 1); | |
166 | for (i = 0; i < L1_ENTRIES_PER_SECTOR; i++) { | |
167 | buf[i] = cpu_to_be64(s->l1_table[l1_start_index + i]); | |
168 | } | |
169 | ||
231bb267 | 170 | ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_ACTIVE_L1, |
cf93980e HR |
171 | s->l1_table_offset + 8 * l1_start_index, sizeof(buf)); |
172 | if (ret < 0) { | |
173 | return ret; | |
174 | } | |
175 | ||
66f82cee | 176 | BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); |
8b3b7206 | 177 | ret = bdrv_pwrite_sync(bs->file, s->l1_table_offset + 8 * l1_start_index, |
f7defcb6 KW |
178 | buf, sizeof(buf)); |
179 | if (ret < 0) { | |
180 | return ret; | |
6583e3c7 KW |
181 | } |
182 | ||
183 | return 0; | |
184 | } | |
185 | ||
45aba42f KW |
186 | /* |
187 | * l2_allocate | |
188 | * | |
189 | * Allocate a new l2 entry in the file. If l1_index points to an already | |
190 | * used entry in the L2 table (i.e. we are doing a copy on write for the L2 | |
191 | * table) copy the contents of the old L2 table into the newly allocated one. | |
192 | * Otherwise the new table is initialized with zeros. | |
193 | * | |
194 | */ | |
195 | ||
c46e1167 | 196 | static int l2_allocate(BlockDriverState *bs, int l1_index, uint64_t **table) |
45aba42f KW |
197 | { |
198 | BDRVQcowState *s = bs->opaque; | |
6583e3c7 | 199 | uint64_t old_l2_offset; |
8585afd8 | 200 | uint64_t *l2_table = NULL; |
f4f0d391 | 201 | int64_t l2_offset; |
c46e1167 | 202 | int ret; |
45aba42f KW |
203 | |
204 | old_l2_offset = s->l1_table[l1_index]; | |
205 | ||
3cce16f4 KW |
206 | trace_qcow2_l2_allocate(bs, l1_index); |
207 | ||
45aba42f KW |
208 | /* allocate a new l2 entry */ |
209 | ||
ed6ccf0f | 210 | l2_offset = qcow2_alloc_clusters(bs, s->l2_size * sizeof(uint64_t)); |
5d757b56 | 211 | if (l2_offset < 0) { |
be0b742e HR |
212 | ret = l2_offset; |
213 | goto fail; | |
5d757b56 | 214 | } |
29c1a730 KW |
215 | |
216 | ret = qcow2_cache_flush(bs, s->refcount_block_cache); | |
217 | if (ret < 0) { | |
218 | goto fail; | |
219 | } | |
45aba42f | 220 | |
45aba42f KW |
221 | /* allocate a new entry in the l2 cache */ |
222 | ||
3cce16f4 | 223 | trace_qcow2_l2_allocate_get_empty(bs, l1_index); |
29c1a730 KW |
224 | ret = qcow2_cache_get_empty(bs, s->l2_table_cache, l2_offset, (void**) table); |
225 | if (ret < 0) { | |
be0b742e | 226 | goto fail; |
29c1a730 KW |
227 | } |
228 | ||
229 | l2_table = *table; | |
45aba42f | 230 | |
8e37f681 | 231 | if ((old_l2_offset & L1E_OFFSET_MASK) == 0) { |
45aba42f KW |
232 | /* if there was no old l2 table, clear the new table */ |
233 | memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); | |
234 | } else { | |
29c1a730 KW |
235 | uint64_t* old_table; |
236 | ||
45aba42f | 237 | /* if there was an old l2 table, read it from the disk */ |
66f82cee | 238 | BLKDBG_EVENT(bs->file, BLKDBG_L2_ALLOC_COW_READ); |
8e37f681 KW |
239 | ret = qcow2_cache_get(bs, s->l2_table_cache, |
240 | old_l2_offset & L1E_OFFSET_MASK, | |
29c1a730 KW |
241 | (void**) &old_table); |
242 | if (ret < 0) { | |
243 | goto fail; | |
244 | } | |
245 | ||
246 | memcpy(l2_table, old_table, s->cluster_size); | |
247 | ||
248 | ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &old_table); | |
c46e1167 | 249 | if (ret < 0) { |
175e1152 | 250 | goto fail; |
c46e1167 | 251 | } |
45aba42f | 252 | } |
29c1a730 | 253 | |
45aba42f | 254 | /* write the l2 table to the file */ |
66f82cee | 255 | BLKDBG_EVENT(bs->file, BLKDBG_L2_ALLOC_WRITE); |
29c1a730 | 256 | |
3cce16f4 | 257 | trace_qcow2_l2_allocate_write_l2(bs, l1_index); |
29c1a730 KW |
258 | qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table); |
259 | ret = qcow2_cache_flush(bs, s->l2_table_cache); | |
c46e1167 | 260 | if (ret < 0) { |
175e1152 KW |
261 | goto fail; |
262 | } | |
263 | ||
264 | /* update the L1 entry */ | |
3cce16f4 | 265 | trace_qcow2_l2_allocate_write_l1(bs, l1_index); |
175e1152 | 266 | s->l1_table[l1_index] = l2_offset | QCOW_OFLAG_COPIED; |
e23e400e | 267 | ret = qcow2_write_l1_entry(bs, l1_index); |
175e1152 KW |
268 | if (ret < 0) { |
269 | goto fail; | |
c46e1167 | 270 | } |
45aba42f | 271 | |
c46e1167 | 272 | *table = l2_table; |
3cce16f4 | 273 | trace_qcow2_l2_allocate_done(bs, l1_index, 0); |
c46e1167 | 274 | return 0; |
175e1152 KW |
275 | |
276 | fail: | |
3cce16f4 | 277 | trace_qcow2_l2_allocate_done(bs, l1_index, ret); |
8585afd8 HR |
278 | if (l2_table != NULL) { |
279 | qcow2_cache_put(bs, s->l2_table_cache, (void**) table); | |
280 | } | |
68dba0bf | 281 | s->l1_table[l1_index] = old_l2_offset; |
e3b21ef9 HR |
282 | if (l2_offset > 0) { |
283 | qcow2_free_clusters(bs, l2_offset, s->l2_size * sizeof(uint64_t), | |
284 | QCOW2_DISCARD_ALWAYS); | |
285 | } | |
175e1152 | 286 | return ret; |
45aba42f KW |
287 | } |
288 | ||
2bfcc4a0 KW |
289 | /* |
290 | * Checks how many clusters in a given L2 table are contiguous in the image | |
291 | * file. As soon as one of the flags in the bitmask stop_flags changes compared | |
292 | * to the first cluster, the search is stopped and the cluster is not counted | |
293 | * as contiguous. (This allows it, for example, to stop at the first compressed | |
294 | * cluster which may require a different handling) | |
295 | */ | |
45aba42f | 296 | static int count_contiguous_clusters(uint64_t nb_clusters, int cluster_size, |
61653008 | 297 | uint64_t *l2_table, uint64_t stop_flags) |
45aba42f KW |
298 | { |
299 | int i; | |
78a52ad5 | 300 | uint64_t mask = stop_flags | L2E_OFFSET_MASK | QCOW_OFLAG_COMPRESSED; |
15684a47 HR |
301 | uint64_t first_entry = be64_to_cpu(l2_table[0]); |
302 | uint64_t offset = first_entry & mask; | |
45aba42f KW |
303 | |
304 | if (!offset) | |
305 | return 0; | |
306 | ||
15684a47 HR |
307 | assert(qcow2_get_cluster_type(first_entry) != QCOW2_CLUSTER_COMPRESSED); |
308 | ||
61653008 | 309 | for (i = 0; i < nb_clusters; i++) { |
2bfcc4a0 KW |
310 | uint64_t l2_entry = be64_to_cpu(l2_table[i]) & mask; |
311 | if (offset + (uint64_t) i * cluster_size != l2_entry) { | |
45aba42f | 312 | break; |
2bfcc4a0 KW |
313 | } |
314 | } | |
45aba42f | 315 | |
61653008 | 316 | return i; |
45aba42f KW |
317 | } |
318 | ||
319 | static int count_contiguous_free_clusters(uint64_t nb_clusters, uint64_t *l2_table) | |
320 | { | |
2bfcc4a0 KW |
321 | int i; |
322 | ||
323 | for (i = 0; i < nb_clusters; i++) { | |
324 | int type = qcow2_get_cluster_type(be64_to_cpu(l2_table[i])); | |
45aba42f | 325 | |
2bfcc4a0 KW |
326 | if (type != QCOW2_CLUSTER_UNALLOCATED) { |
327 | break; | |
328 | } | |
329 | } | |
45aba42f KW |
330 | |
331 | return i; | |
332 | } | |
333 | ||
334 | /* The crypt function is compatible with the linux cryptoloop | |
335 | algorithm for < 4 GB images. NOTE: out_buf == in_buf is | |
336 | supported */ | |
ed6ccf0f KW |
337 | void qcow2_encrypt_sectors(BDRVQcowState *s, int64_t sector_num, |
338 | uint8_t *out_buf, const uint8_t *in_buf, | |
339 | int nb_sectors, int enc, | |
340 | const AES_KEY *key) | |
45aba42f KW |
341 | { |
342 | union { | |
343 | uint64_t ll[2]; | |
344 | uint8_t b[16]; | |
345 | } ivec; | |
346 | int i; | |
347 | ||
348 | for(i = 0; i < nb_sectors; i++) { | |
349 | ivec.ll[0] = cpu_to_le64(sector_num); | |
350 | ivec.ll[1] = 0; | |
351 | AES_cbc_encrypt(in_buf, out_buf, 512, key, | |
352 | ivec.b, enc); | |
353 | sector_num++; | |
354 | in_buf += 512; | |
355 | out_buf += 512; | |
356 | } | |
357 | } | |
358 | ||
aef4acb6 SH |
359 | static int coroutine_fn copy_sectors(BlockDriverState *bs, |
360 | uint64_t start_sect, | |
361 | uint64_t cluster_offset, | |
362 | int n_start, int n_end) | |
45aba42f KW |
363 | { |
364 | BDRVQcowState *s = bs->opaque; | |
aef4acb6 SH |
365 | QEMUIOVector qiov; |
366 | struct iovec iov; | |
45aba42f | 367 | int n, ret; |
1b9f1491 | 368 | |
45aba42f | 369 | n = n_end - n_start; |
1b9f1491 | 370 | if (n <= 0) { |
45aba42f | 371 | return 0; |
1b9f1491 KW |
372 | } |
373 | ||
aef4acb6 SH |
374 | iov.iov_len = n * BDRV_SECTOR_SIZE; |
375 | iov.iov_base = qemu_blockalign(bs, iov.iov_len); | |
376 | ||
377 | qemu_iovec_init_external(&qiov, &iov, 1); | |
1b9f1491 | 378 | |
66f82cee | 379 | BLKDBG_EVENT(bs->file, BLKDBG_COW_READ); |
aef4acb6 | 380 | |
dba28555 HR |
381 | if (!bs->drv) { |
382 | return -ENOMEDIUM; | |
383 | } | |
384 | ||
aef4acb6 SH |
385 | /* Call .bdrv_co_readv() directly instead of using the public block-layer |
386 | * interface. This avoids double I/O throttling and request tracking, | |
387 | * which can lead to deadlock when block layer copy-on-read is enabled. | |
388 | */ | |
389 | ret = bs->drv->bdrv_co_readv(bs, start_sect + n_start, n, &qiov); | |
1b9f1491 KW |
390 | if (ret < 0) { |
391 | goto out; | |
392 | } | |
393 | ||
45aba42f | 394 | if (s->crypt_method) { |
ed6ccf0f | 395 | qcow2_encrypt_sectors(s, start_sect + n_start, |
aef4acb6 | 396 | iov.iov_base, iov.iov_base, n, 1, |
45aba42f KW |
397 | &s->aes_encrypt_key); |
398 | } | |
1b9f1491 | 399 | |
231bb267 | 400 | ret = qcow2_pre_write_overlap_check(bs, 0, |
cf93980e HR |
401 | cluster_offset + n_start * BDRV_SECTOR_SIZE, n * BDRV_SECTOR_SIZE); |
402 | if (ret < 0) { | |
403 | goto out; | |
404 | } | |
405 | ||
66f82cee | 406 | BLKDBG_EVENT(bs->file, BLKDBG_COW_WRITE); |
aef4acb6 | 407 | ret = bdrv_co_writev(bs->file, (cluster_offset >> 9) + n_start, n, &qiov); |
1b9f1491 KW |
408 | if (ret < 0) { |
409 | goto out; | |
410 | } | |
411 | ||
412 | ret = 0; | |
413 | out: | |
aef4acb6 | 414 | qemu_vfree(iov.iov_base); |
1b9f1491 | 415 | return ret; |
45aba42f KW |
416 | } |
417 | ||
418 | ||
419 | /* | |
420 | * get_cluster_offset | |
421 | * | |
1c46efaa KW |
422 | * For a given offset of the disk image, find the cluster offset in |
423 | * qcow2 file. The offset is stored in *cluster_offset. | |
45aba42f | 424 | * |
d57237f2 | 425 | * on entry, *num is the number of contiguous sectors we'd like to |
45aba42f KW |
426 | * access following offset. |
427 | * | |
d57237f2 | 428 | * on exit, *num is the number of contiguous sectors we can read. |
45aba42f | 429 | * |
68d000a3 KW |
430 | * Returns the cluster type (QCOW2_CLUSTER_*) on success, -errno in error |
431 | * cases. | |
45aba42f | 432 | */ |
1c46efaa KW |
433 | int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset, |
434 | int *num, uint64_t *cluster_offset) | |
45aba42f KW |
435 | { |
436 | BDRVQcowState *s = bs->opaque; | |
2cf7cfa1 KW |
437 | unsigned int l2_index; |
438 | uint64_t l1_index, l2_offset, *l2_table; | |
45aba42f | 439 | int l1_bits, c; |
80ee15a6 KW |
440 | unsigned int index_in_cluster, nb_clusters; |
441 | uint64_t nb_available, nb_needed; | |
55c17e98 | 442 | int ret; |
45aba42f KW |
443 | |
444 | index_in_cluster = (offset >> 9) & (s->cluster_sectors - 1); | |
445 | nb_needed = *num + index_in_cluster; | |
446 | ||
447 | l1_bits = s->l2_bits + s->cluster_bits; | |
448 | ||
449 | /* compute how many bytes there are between the offset and | |
450 | * the end of the l1 entry | |
451 | */ | |
452 | ||
80ee15a6 | 453 | nb_available = (1ULL << l1_bits) - (offset & ((1ULL << l1_bits) - 1)); |
45aba42f KW |
454 | |
455 | /* compute the number of available sectors */ | |
456 | ||
457 | nb_available = (nb_available >> 9) + index_in_cluster; | |
458 | ||
459 | if (nb_needed > nb_available) { | |
460 | nb_needed = nb_available; | |
461 | } | |
462 | ||
1c46efaa | 463 | *cluster_offset = 0; |
45aba42f KW |
464 | |
465 | /* seek the the l2 offset in the l1 table */ | |
466 | ||
467 | l1_index = offset >> l1_bits; | |
68d000a3 KW |
468 | if (l1_index >= s->l1_size) { |
469 | ret = QCOW2_CLUSTER_UNALLOCATED; | |
45aba42f | 470 | goto out; |
68d000a3 | 471 | } |
45aba42f | 472 | |
68d000a3 KW |
473 | l2_offset = s->l1_table[l1_index] & L1E_OFFSET_MASK; |
474 | if (!l2_offset) { | |
475 | ret = QCOW2_CLUSTER_UNALLOCATED; | |
45aba42f | 476 | goto out; |
68d000a3 | 477 | } |
45aba42f KW |
478 | |
479 | /* load the l2 table in memory */ | |
480 | ||
55c17e98 KW |
481 | ret = l2_load(bs, l2_offset, &l2_table); |
482 | if (ret < 0) { | |
483 | return ret; | |
1c46efaa | 484 | } |
45aba42f KW |
485 | |
486 | /* find the cluster offset for the given disk offset */ | |
487 | ||
488 | l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1); | |
1c46efaa | 489 | *cluster_offset = be64_to_cpu(l2_table[l2_index]); |
45aba42f KW |
490 | nb_clusters = size_to_clusters(s, nb_needed << 9); |
491 | ||
68d000a3 KW |
492 | ret = qcow2_get_cluster_type(*cluster_offset); |
493 | switch (ret) { | |
494 | case QCOW2_CLUSTER_COMPRESSED: | |
495 | /* Compressed clusters can only be processed one by one */ | |
496 | c = 1; | |
497 | *cluster_offset &= L2E_COMPRESSED_OFFSET_SIZE_MASK; | |
498 | break; | |
6377af48 | 499 | case QCOW2_CLUSTER_ZERO: |
381b487d | 500 | if (s->qcow_version < 3) { |
8885eade | 501 | qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); |
381b487d PB |
502 | return -EIO; |
503 | } | |
6377af48 | 504 | c = count_contiguous_clusters(nb_clusters, s->cluster_size, |
61653008 | 505 | &l2_table[l2_index], QCOW_OFLAG_ZERO); |
6377af48 KW |
506 | *cluster_offset = 0; |
507 | break; | |
68d000a3 | 508 | case QCOW2_CLUSTER_UNALLOCATED: |
45aba42f KW |
509 | /* how many empty clusters ? */ |
510 | c = count_contiguous_free_clusters(nb_clusters, &l2_table[l2_index]); | |
68d000a3 KW |
511 | *cluster_offset = 0; |
512 | break; | |
513 | case QCOW2_CLUSTER_NORMAL: | |
45aba42f KW |
514 | /* how many allocated clusters ? */ |
515 | c = count_contiguous_clusters(nb_clusters, s->cluster_size, | |
61653008 | 516 | &l2_table[l2_index], QCOW_OFLAG_ZERO); |
68d000a3 KW |
517 | *cluster_offset &= L2E_OFFSET_MASK; |
518 | break; | |
1417d7e4 KW |
519 | default: |
520 | abort(); | |
45aba42f KW |
521 | } |
522 | ||
29c1a730 KW |
523 | qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); |
524 | ||
68d000a3 KW |
525 | nb_available = (c * s->cluster_sectors); |
526 | ||
45aba42f KW |
527 | out: |
528 | if (nb_available > nb_needed) | |
529 | nb_available = nb_needed; | |
530 | ||
531 | *num = nb_available - index_in_cluster; | |
532 | ||
68d000a3 | 533 | return ret; |
45aba42f KW |
534 | } |
535 | ||
536 | /* | |
537 | * get_cluster_table | |
538 | * | |
539 | * for a given disk offset, load (and allocate if needed) | |
540 | * the l2 table. | |
541 | * | |
542 | * the l2 table offset in the qcow2 file and the cluster index | |
543 | * in the l2 table are given to the caller. | |
544 | * | |
1e3e8f1a | 545 | * Returns 0 on success, -errno in failure case |
45aba42f | 546 | */ |
45aba42f KW |
547 | static int get_cluster_table(BlockDriverState *bs, uint64_t offset, |
548 | uint64_t **new_l2_table, | |
45aba42f KW |
549 | int *new_l2_index) |
550 | { | |
551 | BDRVQcowState *s = bs->opaque; | |
2cf7cfa1 KW |
552 | unsigned int l2_index; |
553 | uint64_t l1_index, l2_offset; | |
c46e1167 | 554 | uint64_t *l2_table = NULL; |
80ee15a6 | 555 | int ret; |
45aba42f KW |
556 | |
557 | /* seek the the l2 offset in the l1 table */ | |
558 | ||
559 | l1_index = offset >> (s->l2_bits + s->cluster_bits); | |
560 | if (l1_index >= s->l1_size) { | |
72893756 | 561 | ret = qcow2_grow_l1_table(bs, l1_index + 1, false); |
1e3e8f1a KW |
562 | if (ret < 0) { |
563 | return ret; | |
564 | } | |
45aba42f | 565 | } |
8e37f681 | 566 | |
2cf7cfa1 | 567 | assert(l1_index < s->l1_size); |
8e37f681 | 568 | l2_offset = s->l1_table[l1_index] & L1E_OFFSET_MASK; |
45aba42f KW |
569 | |
570 | /* seek the l2 table of the given l2 offset */ | |
571 | ||
8e37f681 | 572 | if (s->l1_table[l1_index] & QCOW_OFLAG_COPIED) { |
45aba42f | 573 | /* load the l2 table in memory */ |
55c17e98 KW |
574 | ret = l2_load(bs, l2_offset, &l2_table); |
575 | if (ret < 0) { | |
576 | return ret; | |
1e3e8f1a | 577 | } |
45aba42f | 578 | } else { |
16fde5f2 | 579 | /* First allocate a new L2 table (and do COW if needed) */ |
c46e1167 KW |
580 | ret = l2_allocate(bs, l1_index, &l2_table); |
581 | if (ret < 0) { | |
582 | return ret; | |
1e3e8f1a | 583 | } |
16fde5f2 KW |
584 | |
585 | /* Then decrease the refcount of the old table */ | |
586 | if (l2_offset) { | |
6cfcb9b8 KW |
587 | qcow2_free_clusters(bs, l2_offset, s->l2_size * sizeof(uint64_t), |
588 | QCOW2_DISCARD_OTHER); | |
16fde5f2 | 589 | } |
45aba42f KW |
590 | } |
591 | ||
592 | /* find the cluster offset for the given disk offset */ | |
593 | ||
594 | l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1); | |
595 | ||
596 | *new_l2_table = l2_table; | |
45aba42f KW |
597 | *new_l2_index = l2_index; |
598 | ||
1e3e8f1a | 599 | return 0; |
45aba42f KW |
600 | } |
601 | ||
602 | /* | |
603 | * alloc_compressed_cluster_offset | |
604 | * | |
605 | * For a given offset of the disk image, return cluster offset in | |
606 | * qcow2 file. | |
607 | * | |
608 | * If the offset is not found, allocate a new compressed cluster. | |
609 | * | |
610 | * Return the cluster offset if successful, | |
611 | * Return 0, otherwise. | |
612 | * | |
613 | */ | |
614 | ||
ed6ccf0f KW |
615 | uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs, |
616 | uint64_t offset, | |
617 | int compressed_size) | |
45aba42f KW |
618 | { |
619 | BDRVQcowState *s = bs->opaque; | |
620 | int l2_index, ret; | |
3948d1d4 | 621 | uint64_t *l2_table; |
f4f0d391 | 622 | int64_t cluster_offset; |
45aba42f KW |
623 | int nb_csectors; |
624 | ||
3948d1d4 | 625 | ret = get_cluster_table(bs, offset, &l2_table, &l2_index); |
1e3e8f1a | 626 | if (ret < 0) { |
45aba42f | 627 | return 0; |
1e3e8f1a | 628 | } |
45aba42f | 629 | |
b0b6862e KW |
630 | /* Compression can't overwrite anything. Fail if the cluster was already |
631 | * allocated. */ | |
45aba42f | 632 | cluster_offset = be64_to_cpu(l2_table[l2_index]); |
b0b6862e | 633 | if (cluster_offset & L2E_OFFSET_MASK) { |
8f1efd00 KW |
634 | qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); |
635 | return 0; | |
636 | } | |
45aba42f | 637 | |
ed6ccf0f | 638 | cluster_offset = qcow2_alloc_bytes(bs, compressed_size); |
5d757b56 | 639 | if (cluster_offset < 0) { |
29c1a730 | 640 | qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); |
5d757b56 KW |
641 | return 0; |
642 | } | |
643 | ||
45aba42f KW |
644 | nb_csectors = ((cluster_offset + compressed_size - 1) >> 9) - |
645 | (cluster_offset >> 9); | |
646 | ||
647 | cluster_offset |= QCOW_OFLAG_COMPRESSED | | |
648 | ((uint64_t)nb_csectors << s->csize_shift); | |
649 | ||
650 | /* update L2 table */ | |
651 | ||
652 | /* compressed clusters never have the copied flag */ | |
653 | ||
66f82cee | 654 | BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE_COMPRESSED); |
29c1a730 | 655 | qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table); |
45aba42f | 656 | l2_table[l2_index] = cpu_to_be64(cluster_offset); |
29c1a730 | 657 | ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); |
79a31189 | 658 | if (ret < 0) { |
29c1a730 | 659 | return 0; |
4c1612d9 KW |
660 | } |
661 | ||
29c1a730 | 662 | return cluster_offset; |
4c1612d9 KW |
663 | } |
664 | ||
593fb83c KW |
665 | static int perform_cow(BlockDriverState *bs, QCowL2Meta *m, Qcow2COWRegion *r) |
666 | { | |
667 | BDRVQcowState *s = bs->opaque; | |
668 | int ret; | |
669 | ||
670 | if (r->nb_sectors == 0) { | |
671 | return 0; | |
672 | } | |
673 | ||
674 | qemu_co_mutex_unlock(&s->lock); | |
675 | ret = copy_sectors(bs, m->offset / BDRV_SECTOR_SIZE, m->alloc_offset, | |
676 | r->offset / BDRV_SECTOR_SIZE, | |
677 | r->offset / BDRV_SECTOR_SIZE + r->nb_sectors); | |
678 | qemu_co_mutex_lock(&s->lock); | |
679 | ||
680 | if (ret < 0) { | |
681 | return ret; | |
682 | } | |
683 | ||
684 | /* | |
685 | * Before we update the L2 table to actually point to the new cluster, we | |
686 | * need to be sure that the refcounts have been increased and COW was | |
687 | * handled. | |
688 | */ | |
689 | qcow2_cache_depends_on_flush(s->l2_table_cache); | |
690 | ||
691 | return 0; | |
692 | } | |
693 | ||
148da7ea | 694 | int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m) |
45aba42f KW |
695 | { |
696 | BDRVQcowState *s = bs->opaque; | |
697 | int i, j = 0, l2_index, ret; | |
593fb83c | 698 | uint64_t *old_cluster, *l2_table; |
250196f1 | 699 | uint64_t cluster_offset = m->alloc_offset; |
45aba42f | 700 | |
3cce16f4 | 701 | trace_qcow2_cluster_link_l2(qemu_coroutine_self(), m->nb_clusters); |
f50f88b9 | 702 | assert(m->nb_clusters > 0); |
45aba42f | 703 | |
7267c094 | 704 | old_cluster = g_malloc(m->nb_clusters * sizeof(uint64_t)); |
45aba42f KW |
705 | |
706 | /* copy content of unmodified sectors */ | |
593fb83c KW |
707 | ret = perform_cow(bs, m, &m->cow_start); |
708 | if (ret < 0) { | |
709 | goto err; | |
45aba42f KW |
710 | } |
711 | ||
593fb83c KW |
712 | ret = perform_cow(bs, m, &m->cow_end); |
713 | if (ret < 0) { | |
714 | goto err; | |
29c1a730 KW |
715 | } |
716 | ||
593fb83c | 717 | /* Update L2 table. */ |
74c4510a | 718 | if (s->use_lazy_refcounts) { |
280d3735 KW |
719 | qcow2_mark_dirty(bs); |
720 | } | |
bfe8043e SH |
721 | if (qcow2_need_accurate_refcounts(s)) { |
722 | qcow2_cache_set_dependency(bs, s->l2_table_cache, | |
723 | s->refcount_block_cache); | |
724 | } | |
280d3735 | 725 | |
3948d1d4 | 726 | ret = get_cluster_table(bs, m->offset, &l2_table, &l2_index); |
1e3e8f1a | 727 | if (ret < 0) { |
45aba42f | 728 | goto err; |
1e3e8f1a | 729 | } |
29c1a730 | 730 | qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table); |
45aba42f | 731 | |
c01dbccb | 732 | assert(l2_index + m->nb_clusters <= s->l2_size); |
45aba42f KW |
733 | for (i = 0; i < m->nb_clusters; i++) { |
734 | /* if two concurrent writes happen to the same unallocated cluster | |
735 | * each write allocates separate cluster and writes data concurrently. | |
736 | * The first one to complete updates l2 table with pointer to its | |
737 | * cluster the second one has to do RMW (which is done above by | |
738 | * copy_sectors()), update l2 table with its cluster pointer and free | |
739 | * old cluster. This is what this loop does */ | |
740 | if(l2_table[l2_index + i] != 0) | |
741 | old_cluster[j++] = l2_table[l2_index + i]; | |
742 | ||
743 | l2_table[l2_index + i] = cpu_to_be64((cluster_offset + | |
744 | (i << s->cluster_bits)) | QCOW_OFLAG_COPIED); | |
745 | } | |
746 | ||
9f8e668e | 747 | |
29c1a730 | 748 | ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); |
c835d00f | 749 | if (ret < 0) { |
45aba42f | 750 | goto err; |
4c1612d9 | 751 | } |
45aba42f | 752 | |
7ec5e6a4 KW |
753 | /* |
754 | * If this was a COW, we need to decrease the refcount of the old cluster. | |
755 | * Also flush bs->file to get the right order for L2 and refcount update. | |
6cfcb9b8 KW |
756 | * |
757 | * Don't discard clusters that reach a refcount of 0 (e.g. compressed | |
758 | * clusters), the next write will reuse them anyway. | |
7ec5e6a4 KW |
759 | */ |
760 | if (j != 0) { | |
7ec5e6a4 | 761 | for (i = 0; i < j; i++) { |
6cfcb9b8 KW |
762 | qcow2_free_any_clusters(bs, be64_to_cpu(old_cluster[i]), 1, |
763 | QCOW2_DISCARD_NEVER); | |
7ec5e6a4 KW |
764 | } |
765 | } | |
45aba42f KW |
766 | |
767 | ret = 0; | |
768 | err: | |
7267c094 | 769 | g_free(old_cluster); |
45aba42f KW |
770 | return ret; |
771 | } | |
772 | ||
bf319ece KW |
773 | /* |
774 | * Returns the number of contiguous clusters that can be used for an allocating | |
775 | * write, but require COW to be performed (this includes yet unallocated space, | |
776 | * which must copy from the backing file) | |
777 | */ | |
778 | static int count_cow_clusters(BDRVQcowState *s, int nb_clusters, | |
779 | uint64_t *l2_table, int l2_index) | |
780 | { | |
143550a8 | 781 | int i; |
bf319ece | 782 | |
143550a8 KW |
783 | for (i = 0; i < nb_clusters; i++) { |
784 | uint64_t l2_entry = be64_to_cpu(l2_table[l2_index + i]); | |
785 | int cluster_type = qcow2_get_cluster_type(l2_entry); | |
786 | ||
787 | switch(cluster_type) { | |
788 | case QCOW2_CLUSTER_NORMAL: | |
789 | if (l2_entry & QCOW_OFLAG_COPIED) { | |
790 | goto out; | |
791 | } | |
bf319ece | 792 | break; |
143550a8 KW |
793 | case QCOW2_CLUSTER_UNALLOCATED: |
794 | case QCOW2_CLUSTER_COMPRESSED: | |
6377af48 | 795 | case QCOW2_CLUSTER_ZERO: |
bf319ece | 796 | break; |
143550a8 KW |
797 | default: |
798 | abort(); | |
799 | } | |
bf319ece KW |
800 | } |
801 | ||
143550a8 | 802 | out: |
bf319ece KW |
803 | assert(i <= nb_clusters); |
804 | return i; | |
805 | } | |
806 | ||
250196f1 | 807 | /* |
226c3c26 KW |
808 | * Check if there already is an AIO write request in flight which allocates |
809 | * the same cluster. In this case we need to wait until the previous | |
810 | * request has completed and updated the L2 table accordingly. | |
65eb2e35 KW |
811 | * |
812 | * Returns: | |
813 | * 0 if there was no dependency. *cur_bytes indicates the number of | |
814 | * bytes from guest_offset that can be read before the next | |
815 | * dependency must be processed (or the request is complete) | |
816 | * | |
817 | * -EAGAIN if we had to wait for another request, previously gathered | |
818 | * information on cluster allocation may be invalid now. The caller | |
819 | * must start over anyway, so consider *cur_bytes undefined. | |
250196f1 | 820 | */ |
226c3c26 | 821 | static int handle_dependencies(BlockDriverState *bs, uint64_t guest_offset, |
ecdd5333 | 822 | uint64_t *cur_bytes, QCowL2Meta **m) |
250196f1 KW |
823 | { |
824 | BDRVQcowState *s = bs->opaque; | |
250196f1 | 825 | QCowL2Meta *old_alloc; |
65eb2e35 | 826 | uint64_t bytes = *cur_bytes; |
250196f1 | 827 | |
250196f1 KW |
828 | QLIST_FOREACH(old_alloc, &s->cluster_allocs, next_in_flight) { |
829 | ||
65eb2e35 KW |
830 | uint64_t start = guest_offset; |
831 | uint64_t end = start + bytes; | |
832 | uint64_t old_start = l2meta_cow_start(old_alloc); | |
833 | uint64_t old_end = l2meta_cow_end(old_alloc); | |
250196f1 | 834 | |
d9d74f41 | 835 | if (end <= old_start || start >= old_end) { |
250196f1 KW |
836 | /* No intersection */ |
837 | } else { | |
838 | if (start < old_start) { | |
839 | /* Stop at the start of a running allocation */ | |
65eb2e35 | 840 | bytes = old_start - start; |
250196f1 | 841 | } else { |
65eb2e35 | 842 | bytes = 0; |
250196f1 KW |
843 | } |
844 | ||
ecdd5333 KW |
845 | /* Stop if already an l2meta exists. After yielding, it wouldn't |
846 | * be valid any more, so we'd have to clean up the old L2Metas | |
847 | * and deal with requests depending on them before starting to | |
848 | * gather new ones. Not worth the trouble. */ | |
849 | if (bytes == 0 && *m) { | |
850 | *cur_bytes = 0; | |
851 | return 0; | |
852 | } | |
853 | ||
65eb2e35 | 854 | if (bytes == 0) { |
250196f1 KW |
855 | /* Wait for the dependency to complete. We need to recheck |
856 | * the free/allocated clusters when we continue. */ | |
857 | qemu_co_mutex_unlock(&s->lock); | |
858 | qemu_co_queue_wait(&old_alloc->dependent_requests); | |
859 | qemu_co_mutex_lock(&s->lock); | |
860 | return -EAGAIN; | |
861 | } | |
862 | } | |
863 | } | |
864 | ||
65eb2e35 KW |
865 | /* Make sure that existing clusters and new allocations are only used up to |
866 | * the next dependency if we shortened the request above */ | |
867 | *cur_bytes = bytes; | |
250196f1 | 868 | |
226c3c26 KW |
869 | return 0; |
870 | } | |
871 | ||
0af729ec KW |
872 | /* |
873 | * Checks how many already allocated clusters that don't require a copy on | |
874 | * write there are at the given guest_offset (up to *bytes). If | |
875 | * *host_offset is not zero, only physically contiguous clusters beginning at | |
876 | * this host offset are counted. | |
877 | * | |
411d62b0 KW |
878 | * Note that guest_offset may not be cluster aligned. In this case, the |
879 | * returned *host_offset points to exact byte referenced by guest_offset and | |
880 | * therefore isn't cluster aligned as well. | |
0af729ec KW |
881 | * |
882 | * Returns: | |
883 | * 0: if no allocated clusters are available at the given offset. | |
884 | * *bytes is normally unchanged. It is set to 0 if the cluster | |
885 | * is allocated and doesn't need COW, but doesn't have the right | |
886 | * physical offset. | |
887 | * | |
888 | * 1: if allocated clusters that don't require a COW are available at | |
889 | * the requested offset. *bytes may have decreased and describes | |
890 | * the length of the area that can be written to. | |
891 | * | |
892 | * -errno: in error cases | |
0af729ec KW |
893 | */ |
894 | static int handle_copied(BlockDriverState *bs, uint64_t guest_offset, | |
c53ede9f | 895 | uint64_t *host_offset, uint64_t *bytes, QCowL2Meta **m) |
0af729ec KW |
896 | { |
897 | BDRVQcowState *s = bs->opaque; | |
898 | int l2_index; | |
899 | uint64_t cluster_offset; | |
900 | uint64_t *l2_table; | |
acb0467f | 901 | unsigned int nb_clusters; |
c53ede9f | 902 | unsigned int keep_clusters; |
0af729ec KW |
903 | int ret, pret; |
904 | ||
905 | trace_qcow2_handle_copied(qemu_coroutine_self(), guest_offset, *host_offset, | |
906 | *bytes); | |
0af729ec | 907 | |
411d62b0 KW |
908 | assert(*host_offset == 0 || offset_into_cluster(s, guest_offset) |
909 | == offset_into_cluster(s, *host_offset)); | |
910 | ||
acb0467f KW |
911 | /* |
912 | * Calculate the number of clusters to look for. We stop at L2 table | |
913 | * boundaries to keep things simple. | |
914 | */ | |
915 | nb_clusters = | |
916 | size_to_clusters(s, offset_into_cluster(s, guest_offset) + *bytes); | |
917 | ||
918 | l2_index = offset_to_l2_index(s, guest_offset); | |
919 | nb_clusters = MIN(nb_clusters, s->l2_size - l2_index); | |
920 | ||
0af729ec KW |
921 | /* Find L2 entry for the first involved cluster */ |
922 | ret = get_cluster_table(bs, guest_offset, &l2_table, &l2_index); | |
923 | if (ret < 0) { | |
924 | return ret; | |
925 | } | |
926 | ||
927 | cluster_offset = be64_to_cpu(l2_table[l2_index]); | |
928 | ||
929 | /* Check how many clusters are already allocated and don't need COW */ | |
930 | if (qcow2_get_cluster_type(cluster_offset) == QCOW2_CLUSTER_NORMAL | |
931 | && (cluster_offset & QCOW_OFLAG_COPIED)) | |
932 | { | |
e62daaf6 KW |
933 | /* If a specific host_offset is required, check it */ |
934 | bool offset_matches = | |
935 | (cluster_offset & L2E_OFFSET_MASK) == *host_offset; | |
936 | ||
937 | if (*host_offset != 0 && !offset_matches) { | |
938 | *bytes = 0; | |
939 | ret = 0; | |
940 | goto out; | |
941 | } | |
942 | ||
0af729ec | 943 | /* We keep all QCOW_OFLAG_COPIED clusters */ |
c53ede9f | 944 | keep_clusters = |
acb0467f | 945 | count_contiguous_clusters(nb_clusters, s->cluster_size, |
61653008 | 946 | &l2_table[l2_index], |
0af729ec | 947 | QCOW_OFLAG_COPIED | QCOW_OFLAG_ZERO); |
c53ede9f KW |
948 | assert(keep_clusters <= nb_clusters); |
949 | ||
950 | *bytes = MIN(*bytes, | |
951 | keep_clusters * s->cluster_size | |
952 | - offset_into_cluster(s, guest_offset)); | |
0af729ec KW |
953 | |
954 | ret = 1; | |
955 | } else { | |
0af729ec KW |
956 | ret = 0; |
957 | } | |
958 | ||
0af729ec | 959 | /* Cleanup */ |
e62daaf6 | 960 | out: |
0af729ec KW |
961 | pret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); |
962 | if (pret < 0) { | |
963 | return pret; | |
964 | } | |
965 | ||
e62daaf6 KW |
966 | /* Only return a host offset if we actually made progress. Otherwise we |
967 | * would make requirements for handle_alloc() that it can't fulfill */ | |
968 | if (ret) { | |
411d62b0 KW |
969 | *host_offset = (cluster_offset & L2E_OFFSET_MASK) |
970 | + offset_into_cluster(s, guest_offset); | |
e62daaf6 KW |
971 | } |
972 | ||
0af729ec KW |
973 | return ret; |
974 | } | |
975 | ||
226c3c26 KW |
976 | /* |
977 | * Allocates new clusters for the given guest_offset. | |
978 | * | |
979 | * At most *nb_clusters are allocated, and on return *nb_clusters is updated to | |
980 | * contain the number of clusters that have been allocated and are contiguous | |
981 | * in the image file. | |
982 | * | |
983 | * If *host_offset is non-zero, it specifies the offset in the image file at | |
984 | * which the new clusters must start. *nb_clusters can be 0 on return in this | |
985 | * case if the cluster at host_offset is already in use. If *host_offset is | |
986 | * zero, the clusters can be allocated anywhere in the image file. | |
987 | * | |
988 | * *host_offset is updated to contain the offset into the image file at which | |
989 | * the first allocated cluster starts. | |
990 | * | |
991 | * Return 0 on success and -errno in error cases. -EAGAIN means that the | |
992 | * function has been waiting for another request and the allocation must be | |
993 | * restarted, but the whole request should not be failed. | |
994 | */ | |
995 | static int do_alloc_cluster_offset(BlockDriverState *bs, uint64_t guest_offset, | |
996 | uint64_t *host_offset, unsigned int *nb_clusters) | |
997 | { | |
998 | BDRVQcowState *s = bs->opaque; | |
226c3c26 KW |
999 | |
1000 | trace_qcow2_do_alloc_clusters_offset(qemu_coroutine_self(), guest_offset, | |
1001 | *host_offset, *nb_clusters); | |
1002 | ||
250196f1 KW |
1003 | /* Allocate new clusters */ |
1004 | trace_qcow2_cluster_alloc_phys(qemu_coroutine_self()); | |
1005 | if (*host_offset == 0) { | |
df021791 KW |
1006 | int64_t cluster_offset = |
1007 | qcow2_alloc_clusters(bs, *nb_clusters * s->cluster_size); | |
1008 | if (cluster_offset < 0) { | |
1009 | return cluster_offset; | |
1010 | } | |
1011 | *host_offset = cluster_offset; | |
1012 | return 0; | |
250196f1 | 1013 | } else { |
17a71e58 | 1014 | int ret = qcow2_alloc_clusters_at(bs, *host_offset, *nb_clusters); |
df021791 KW |
1015 | if (ret < 0) { |
1016 | return ret; | |
1017 | } | |
1018 | *nb_clusters = ret; | |
1019 | return 0; | |
250196f1 | 1020 | } |
250196f1 KW |
1021 | } |
1022 | ||
10f0ed8b KW |
1023 | /* |
1024 | * Allocates new clusters for an area that either is yet unallocated or needs a | |
1025 | * copy on write. If *host_offset is non-zero, clusters are only allocated if | |
1026 | * the new allocation can match the specified host offset. | |
1027 | * | |
411d62b0 KW |
1028 | * Note that guest_offset may not be cluster aligned. In this case, the |
1029 | * returned *host_offset points to exact byte referenced by guest_offset and | |
1030 | * therefore isn't cluster aligned as well. | |
10f0ed8b KW |
1031 | * |
1032 | * Returns: | |
1033 | * 0: if no clusters could be allocated. *bytes is set to 0, | |
1034 | * *host_offset is left unchanged. | |
1035 | * | |
1036 | * 1: if new clusters were allocated. *bytes may be decreased if the | |
1037 | * new allocation doesn't cover all of the requested area. | |
1038 | * *host_offset is updated to contain the host offset of the first | |
1039 | * newly allocated cluster. | |
1040 | * | |
1041 | * -errno: in error cases | |
10f0ed8b KW |
1042 | */ |
1043 | static int handle_alloc(BlockDriverState *bs, uint64_t guest_offset, | |
c37f4cd7 | 1044 | uint64_t *host_offset, uint64_t *bytes, QCowL2Meta **m) |
10f0ed8b KW |
1045 | { |
1046 | BDRVQcowState *s = bs->opaque; | |
1047 | int l2_index; | |
1048 | uint64_t *l2_table; | |
1049 | uint64_t entry; | |
f5bc6350 | 1050 | unsigned int nb_clusters; |
10f0ed8b KW |
1051 | int ret; |
1052 | ||
10f0ed8b | 1053 | uint64_t alloc_cluster_offset; |
10f0ed8b KW |
1054 | |
1055 | trace_qcow2_handle_alloc(qemu_coroutine_self(), guest_offset, *host_offset, | |
1056 | *bytes); | |
1057 | assert(*bytes > 0); | |
1058 | ||
f5bc6350 KW |
1059 | /* |
1060 | * Calculate the number of clusters to look for. We stop at L2 table | |
1061 | * boundaries to keep things simple. | |
1062 | */ | |
c37f4cd7 KW |
1063 | nb_clusters = |
1064 | size_to_clusters(s, offset_into_cluster(s, guest_offset) + *bytes); | |
1065 | ||
f5bc6350 | 1066 | l2_index = offset_to_l2_index(s, guest_offset); |
c37f4cd7 | 1067 | nb_clusters = MIN(nb_clusters, s->l2_size - l2_index); |
f5bc6350 | 1068 | |
10f0ed8b KW |
1069 | /* Find L2 entry for the first involved cluster */ |
1070 | ret = get_cluster_table(bs, guest_offset, &l2_table, &l2_index); | |
1071 | if (ret < 0) { | |
1072 | return ret; | |
1073 | } | |
1074 | ||
3b8e2e26 | 1075 | entry = be64_to_cpu(l2_table[l2_index]); |
10f0ed8b KW |
1076 | |
1077 | /* For the moment, overwrite compressed clusters one by one */ | |
1078 | if (entry & QCOW_OFLAG_COMPRESSED) { | |
1079 | nb_clusters = 1; | |
1080 | } else { | |
3b8e2e26 | 1081 | nb_clusters = count_cow_clusters(s, nb_clusters, l2_table, l2_index); |
10f0ed8b KW |
1082 | } |
1083 | ||
ecdd5333 KW |
1084 | /* This function is only called when there were no non-COW clusters, so if |
1085 | * we can't find any unallocated or COW clusters either, something is | |
1086 | * wrong with our code. */ | |
1087 | assert(nb_clusters > 0); | |
1088 | ||
10f0ed8b KW |
1089 | ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); |
1090 | if (ret < 0) { | |
1091 | return ret; | |
1092 | } | |
1093 | ||
10f0ed8b | 1094 | /* Allocate, if necessary at a given offset in the image file */ |
411d62b0 | 1095 | alloc_cluster_offset = start_of_cluster(s, *host_offset); |
83baa9a4 | 1096 | ret = do_alloc_cluster_offset(bs, guest_offset, &alloc_cluster_offset, |
10f0ed8b KW |
1097 | &nb_clusters); |
1098 | if (ret < 0) { | |
1099 | goto fail; | |
1100 | } | |
1101 | ||
83baa9a4 KW |
1102 | /* Can't extend contiguous allocation */ |
1103 | if (nb_clusters == 0) { | |
10f0ed8b KW |
1104 | *bytes = 0; |
1105 | return 0; | |
1106 | } | |
1107 | ||
83baa9a4 KW |
1108 | /* |
1109 | * Save info needed for meta data update. | |
1110 | * | |
1111 | * requested_sectors: Number of sectors from the start of the first | |
1112 | * newly allocated cluster to the end of the (possibly shortened | |
1113 | * before) write request. | |
1114 | * | |
1115 | * avail_sectors: Number of sectors from the start of the first | |
1116 | * newly allocated to the end of the last newly allocated cluster. | |
1117 | * | |
1118 | * nb_sectors: The number of sectors from the start of the first | |
1119 | * newly allocated cluster to the end of the area that the write | |
1120 | * request actually writes to (excluding COW at the end) | |
1121 | */ | |
1122 | int requested_sectors = | |
1123 | (*bytes + offset_into_cluster(s, guest_offset)) | |
1124 | >> BDRV_SECTOR_BITS; | |
1125 | int avail_sectors = nb_clusters | |
1126 | << (s->cluster_bits - BDRV_SECTOR_BITS); | |
1127 | int alloc_n_start = offset_into_cluster(s, guest_offset) | |
1128 | >> BDRV_SECTOR_BITS; | |
1129 | int nb_sectors = MIN(requested_sectors, avail_sectors); | |
88c6588c | 1130 | QCowL2Meta *old_m = *m; |
83baa9a4 | 1131 | |
83baa9a4 KW |
1132 | *m = g_malloc0(sizeof(**m)); |
1133 | ||
1134 | **m = (QCowL2Meta) { | |
88c6588c KW |
1135 | .next = old_m, |
1136 | ||
411d62b0 | 1137 | .alloc_offset = alloc_cluster_offset, |
83baa9a4 KW |
1138 | .offset = start_of_cluster(s, guest_offset), |
1139 | .nb_clusters = nb_clusters, | |
1140 | .nb_available = nb_sectors, | |
1141 | ||
1142 | .cow_start = { | |
1143 | .offset = 0, | |
1144 | .nb_sectors = alloc_n_start, | |
1145 | }, | |
1146 | .cow_end = { | |
1147 | .offset = nb_sectors * BDRV_SECTOR_SIZE, | |
1148 | .nb_sectors = avail_sectors - nb_sectors, | |
1149 | }, | |
1150 | }; | |
1151 | qemu_co_queue_init(&(*m)->dependent_requests); | |
1152 | QLIST_INSERT_HEAD(&s->cluster_allocs, *m, next_in_flight); | |
1153 | ||
411d62b0 | 1154 | *host_offset = alloc_cluster_offset + offset_into_cluster(s, guest_offset); |
83baa9a4 KW |
1155 | *bytes = MIN(*bytes, (nb_sectors * BDRV_SECTOR_SIZE) |
1156 | - offset_into_cluster(s, guest_offset)); | |
1157 | assert(*bytes != 0); | |
1158 | ||
10f0ed8b KW |
1159 | return 1; |
1160 | ||
1161 | fail: | |
1162 | if (*m && (*m)->nb_clusters > 0) { | |
1163 | QLIST_REMOVE(*m, next_in_flight); | |
1164 | } | |
1165 | return ret; | |
1166 | } | |
1167 | ||
45aba42f KW |
1168 | /* |
1169 | * alloc_cluster_offset | |
1170 | * | |
250196f1 KW |
1171 | * For a given offset on the virtual disk, find the cluster offset in qcow2 |
1172 | * file. If the offset is not found, allocate a new cluster. | |
45aba42f | 1173 | * |
250196f1 | 1174 | * If the cluster was already allocated, m->nb_clusters is set to 0 and |
a7912369 | 1175 | * other fields in m are meaningless. |
148da7ea KW |
1176 | * |
1177 | * If the cluster is newly allocated, m->nb_clusters is set to the number of | |
68d100e9 KW |
1178 | * contiguous clusters that have been allocated. In this case, the other |
1179 | * fields of m are valid and contain information about the first allocated | |
1180 | * cluster. | |
45aba42f | 1181 | * |
68d100e9 KW |
1182 | * If the request conflicts with another write request in flight, the coroutine |
1183 | * is queued and will be reentered when the dependency has completed. | |
148da7ea KW |
1184 | * |
1185 | * Return 0 on success and -errno in error cases | |
45aba42f | 1186 | */ |
f4f0d391 | 1187 | int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset, |
16f0587e | 1188 | int *num, uint64_t *host_offset, QCowL2Meta **m) |
45aba42f KW |
1189 | { |
1190 | BDRVQcowState *s = bs->opaque; | |
710c2496 | 1191 | uint64_t start, remaining; |
250196f1 | 1192 | uint64_t cluster_offset; |
65eb2e35 | 1193 | uint64_t cur_bytes; |
710c2496 | 1194 | int ret; |
45aba42f | 1195 | |
16f0587e | 1196 | trace_qcow2_alloc_clusters_offset(qemu_coroutine_self(), offset, *num); |
3cce16f4 | 1197 | |
16f0587e | 1198 | assert((offset & ~BDRV_SECTOR_MASK) == 0); |
710c2496 | 1199 | |
72424114 | 1200 | again: |
16f0587e HT |
1201 | start = offset; |
1202 | remaining = *num << BDRV_SECTOR_BITS; | |
0af729ec KW |
1203 | cluster_offset = 0; |
1204 | *host_offset = 0; | |
ecdd5333 KW |
1205 | cur_bytes = 0; |
1206 | *m = NULL; | |
0af729ec | 1207 | |
2c3b32d2 | 1208 | while (true) { |
ecdd5333 KW |
1209 | |
1210 | if (!*host_offset) { | |
1211 | *host_offset = start_of_cluster(s, cluster_offset); | |
1212 | } | |
1213 | ||
1214 | assert(remaining >= cur_bytes); | |
1215 | ||
1216 | start += cur_bytes; | |
1217 | remaining -= cur_bytes; | |
1218 | cluster_offset += cur_bytes; | |
1219 | ||
1220 | if (remaining == 0) { | |
1221 | break; | |
1222 | } | |
1223 | ||
1224 | cur_bytes = remaining; | |
1225 | ||
2c3b32d2 KW |
1226 | /* |
1227 | * Now start gathering as many contiguous clusters as possible: | |
1228 | * | |
1229 | * 1. Check for overlaps with in-flight allocations | |
1230 | * | |
1231 | * a) Overlap not in the first cluster -> shorten this request and | |
1232 | * let the caller handle the rest in its next loop iteration. | |
1233 | * | |
1234 | * b) Real overlaps of two requests. Yield and restart the search | |
1235 | * for contiguous clusters (the situation could have changed | |
1236 | * while we were sleeping) | |
1237 | * | |
1238 | * c) TODO: Request starts in the same cluster as the in-flight | |
1239 | * allocation ends. Shorten the COW of the in-fight allocation, | |
1240 | * set cluster_offset to write to the same cluster and set up | |
1241 | * the right synchronisation between the in-flight request and | |
1242 | * the new one. | |
1243 | */ | |
ecdd5333 | 1244 | ret = handle_dependencies(bs, start, &cur_bytes, m); |
2c3b32d2 | 1245 | if (ret == -EAGAIN) { |
ecdd5333 KW |
1246 | /* Currently handle_dependencies() doesn't yield if we already had |
1247 | * an allocation. If it did, we would have to clean up the L2Meta | |
1248 | * structs before starting over. */ | |
1249 | assert(*m == NULL); | |
2c3b32d2 KW |
1250 | goto again; |
1251 | } else if (ret < 0) { | |
1252 | return ret; | |
ecdd5333 KW |
1253 | } else if (cur_bytes == 0) { |
1254 | break; | |
2c3b32d2 KW |
1255 | } else { |
1256 | /* handle_dependencies() may have decreased cur_bytes (shortened | |
1257 | * the allocations below) so that the next dependency is processed | |
1258 | * correctly during the next loop iteration. */ | |
0af729ec | 1259 | } |
710c2496 | 1260 | |
2c3b32d2 KW |
1261 | /* |
1262 | * 2. Count contiguous COPIED clusters. | |
1263 | */ | |
1264 | ret = handle_copied(bs, start, &cluster_offset, &cur_bytes, m); | |
1265 | if (ret < 0) { | |
1266 | return ret; | |
1267 | } else if (ret) { | |
ecdd5333 | 1268 | continue; |
2c3b32d2 KW |
1269 | } else if (cur_bytes == 0) { |
1270 | break; | |
1271 | } | |
060bee89 | 1272 | |
2c3b32d2 KW |
1273 | /* |
1274 | * 3. If the request still hasn't completed, allocate new clusters, | |
1275 | * considering any cluster_offset of steps 1c or 2. | |
1276 | */ | |
1277 | ret = handle_alloc(bs, start, &cluster_offset, &cur_bytes, m); | |
1278 | if (ret < 0) { | |
1279 | return ret; | |
1280 | } else if (ret) { | |
ecdd5333 | 1281 | continue; |
2c3b32d2 KW |
1282 | } else { |
1283 | assert(cur_bytes == 0); | |
1284 | break; | |
1285 | } | |
f5bc6350 | 1286 | } |
10f0ed8b | 1287 | |
16f0587e | 1288 | *num -= remaining >> BDRV_SECTOR_BITS; |
710c2496 KW |
1289 | assert(*num > 0); |
1290 | assert(*host_offset != 0); | |
45aba42f | 1291 | |
148da7ea | 1292 | return 0; |
45aba42f KW |
1293 | } |
1294 | ||
1295 | static int decompress_buffer(uint8_t *out_buf, int out_buf_size, | |
1296 | const uint8_t *buf, int buf_size) | |
1297 | { | |
1298 | z_stream strm1, *strm = &strm1; | |
1299 | int ret, out_len; | |
1300 | ||
1301 | memset(strm, 0, sizeof(*strm)); | |
1302 | ||
1303 | strm->next_in = (uint8_t *)buf; | |
1304 | strm->avail_in = buf_size; | |
1305 | strm->next_out = out_buf; | |
1306 | strm->avail_out = out_buf_size; | |
1307 | ||
1308 | ret = inflateInit2(strm, -12); | |
1309 | if (ret != Z_OK) | |
1310 | return -1; | |
1311 | ret = inflate(strm, Z_FINISH); | |
1312 | out_len = strm->next_out - out_buf; | |
1313 | if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || | |
1314 | out_len != out_buf_size) { | |
1315 | inflateEnd(strm); | |
1316 | return -1; | |
1317 | } | |
1318 | inflateEnd(strm); | |
1319 | return 0; | |
1320 | } | |
1321 | ||
66f82cee | 1322 | int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset) |
45aba42f | 1323 | { |
66f82cee | 1324 | BDRVQcowState *s = bs->opaque; |
45aba42f KW |
1325 | int ret, csize, nb_csectors, sector_offset; |
1326 | uint64_t coffset; | |
1327 | ||
1328 | coffset = cluster_offset & s->cluster_offset_mask; | |
1329 | if (s->cluster_cache_offset != coffset) { | |
1330 | nb_csectors = ((cluster_offset >> s->csize_shift) & s->csize_mask) + 1; | |
1331 | sector_offset = coffset & 511; | |
1332 | csize = nb_csectors * 512 - sector_offset; | |
66f82cee KW |
1333 | BLKDBG_EVENT(bs->file, BLKDBG_READ_COMPRESSED); |
1334 | ret = bdrv_read(bs->file, coffset >> 9, s->cluster_data, nb_csectors); | |
45aba42f | 1335 | if (ret < 0) { |
8af36488 | 1336 | return ret; |
45aba42f KW |
1337 | } |
1338 | if (decompress_buffer(s->cluster_cache, s->cluster_size, | |
1339 | s->cluster_data + sector_offset, csize) < 0) { | |
8af36488 | 1340 | return -EIO; |
45aba42f KW |
1341 | } |
1342 | s->cluster_cache_offset = coffset; | |
1343 | } | |
1344 | return 0; | |
1345 | } | |
5ea929e3 KW |
1346 | |
1347 | /* | |
1348 | * This discards as many clusters of nb_clusters as possible at once (i.e. | |
1349 | * all clusters in the same L2 table) and returns the number of discarded | |
1350 | * clusters. | |
1351 | */ | |
1352 | static int discard_single_l2(BlockDriverState *bs, uint64_t offset, | |
670df5e3 | 1353 | unsigned int nb_clusters, enum qcow2_discard_type type) |
5ea929e3 KW |
1354 | { |
1355 | BDRVQcowState *s = bs->opaque; | |
3948d1d4 | 1356 | uint64_t *l2_table; |
5ea929e3 KW |
1357 | int l2_index; |
1358 | int ret; | |
1359 | int i; | |
1360 | ||
3948d1d4 | 1361 | ret = get_cluster_table(bs, offset, &l2_table, &l2_index); |
5ea929e3 KW |
1362 | if (ret < 0) { |
1363 | return ret; | |
1364 | } | |
1365 | ||
1366 | /* Limit nb_clusters to one L2 table */ | |
1367 | nb_clusters = MIN(nb_clusters, s->l2_size - l2_index); | |
1368 | ||
1369 | for (i = 0; i < nb_clusters; i++) { | |
c883db0d | 1370 | uint64_t old_l2_entry; |
5ea929e3 | 1371 | |
c883db0d | 1372 | old_l2_entry = be64_to_cpu(l2_table[l2_index + i]); |
a71835a0 KW |
1373 | |
1374 | /* | |
1375 | * Make sure that a discarded area reads back as zeroes for v3 images | |
1376 | * (we cannot do it for v2 without actually writing a zero-filled | |
1377 | * buffer). We can skip the operation if the cluster is already marked | |
1378 | * as zero, or if it's unallocated and we don't have a backing file. | |
1379 | * | |
1380 | * TODO We might want to use bdrv_get_block_status(bs) here, but we're | |
1381 | * holding s->lock, so that doesn't work today. | |
1382 | */ | |
c883db0d HR |
1383 | switch (qcow2_get_cluster_type(old_l2_entry)) { |
1384 | case QCOW2_CLUSTER_UNALLOCATED: | |
1385 | if (!bs->backing_hd) { | |
1386 | continue; | |
1387 | } | |
1388 | break; | |
1389 | ||
1390 | case QCOW2_CLUSTER_ZERO: | |
1391 | continue; | |
1392 | ||
1393 | case QCOW2_CLUSTER_NORMAL: | |
1394 | case QCOW2_CLUSTER_COMPRESSED: | |
1395 | break; | |
1396 | ||
1397 | default: | |
1398 | abort(); | |
5ea929e3 KW |
1399 | } |
1400 | ||
1401 | /* First remove L2 entries */ | |
1402 | qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table); | |
a71835a0 KW |
1403 | if (s->qcow_version >= 3) { |
1404 | l2_table[l2_index + i] = cpu_to_be64(QCOW_OFLAG_ZERO); | |
1405 | } else { | |
1406 | l2_table[l2_index + i] = cpu_to_be64(0); | |
1407 | } | |
5ea929e3 KW |
1408 | |
1409 | /* Then decrease the refcount */ | |
c883db0d | 1410 | qcow2_free_any_clusters(bs, old_l2_entry, 1, type); |
5ea929e3 KW |
1411 | } |
1412 | ||
1413 | ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); | |
1414 | if (ret < 0) { | |
1415 | return ret; | |
1416 | } | |
1417 | ||
1418 | return nb_clusters; | |
1419 | } | |
1420 | ||
1421 | int qcow2_discard_clusters(BlockDriverState *bs, uint64_t offset, | |
670df5e3 | 1422 | int nb_sectors, enum qcow2_discard_type type) |
5ea929e3 KW |
1423 | { |
1424 | BDRVQcowState *s = bs->opaque; | |
1425 | uint64_t end_offset; | |
1426 | unsigned int nb_clusters; | |
1427 | int ret; | |
1428 | ||
1429 | end_offset = offset + (nb_sectors << BDRV_SECTOR_BITS); | |
1430 | ||
1431 | /* Round start up and end down */ | |
1432 | offset = align_offset(offset, s->cluster_size); | |
ac95acdb | 1433 | end_offset = start_of_cluster(s, end_offset); |
5ea929e3 KW |
1434 | |
1435 | if (offset > end_offset) { | |
1436 | return 0; | |
1437 | } | |
1438 | ||
1439 | nb_clusters = size_to_clusters(s, end_offset - offset); | |
1440 | ||
0b919fae KW |
1441 | s->cache_discards = true; |
1442 | ||
5ea929e3 KW |
1443 | /* Each L2 table is handled by its own loop iteration */ |
1444 | while (nb_clusters > 0) { | |
670df5e3 | 1445 | ret = discard_single_l2(bs, offset, nb_clusters, type); |
5ea929e3 | 1446 | if (ret < 0) { |
0b919fae | 1447 | goto fail; |
5ea929e3 KW |
1448 | } |
1449 | ||
1450 | nb_clusters -= ret; | |
1451 | offset += (ret * s->cluster_size); | |
1452 | } | |
1453 | ||
0b919fae KW |
1454 | ret = 0; |
1455 | fail: | |
1456 | s->cache_discards = false; | |
1457 | qcow2_process_discards(bs, ret); | |
1458 | ||
1459 | return ret; | |
5ea929e3 | 1460 | } |
621f0589 KW |
1461 | |
1462 | /* | |
1463 | * This zeroes as many clusters of nb_clusters as possible at once (i.e. | |
1464 | * all clusters in the same L2 table) and returns the number of zeroed | |
1465 | * clusters. | |
1466 | */ | |
1467 | static int zero_single_l2(BlockDriverState *bs, uint64_t offset, | |
1468 | unsigned int nb_clusters) | |
1469 | { | |
1470 | BDRVQcowState *s = bs->opaque; | |
1471 | uint64_t *l2_table; | |
1472 | int l2_index; | |
1473 | int ret; | |
1474 | int i; | |
1475 | ||
1476 | ret = get_cluster_table(bs, offset, &l2_table, &l2_index); | |
1477 | if (ret < 0) { | |
1478 | return ret; | |
1479 | } | |
1480 | ||
1481 | /* Limit nb_clusters to one L2 table */ | |
1482 | nb_clusters = MIN(nb_clusters, s->l2_size - l2_index); | |
1483 | ||
1484 | for (i = 0; i < nb_clusters; i++) { | |
1485 | uint64_t old_offset; | |
1486 | ||
1487 | old_offset = be64_to_cpu(l2_table[l2_index + i]); | |
1488 | ||
1489 | /* Update L2 entries */ | |
1490 | qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table); | |
1491 | if (old_offset & QCOW_OFLAG_COMPRESSED) { | |
1492 | l2_table[l2_index + i] = cpu_to_be64(QCOW_OFLAG_ZERO); | |
6cfcb9b8 | 1493 | qcow2_free_any_clusters(bs, old_offset, 1, QCOW2_DISCARD_REQUEST); |
621f0589 KW |
1494 | } else { |
1495 | l2_table[l2_index + i] |= cpu_to_be64(QCOW_OFLAG_ZERO); | |
1496 | } | |
1497 | } | |
1498 | ||
1499 | ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); | |
1500 | if (ret < 0) { | |
1501 | return ret; | |
1502 | } | |
1503 | ||
1504 | return nb_clusters; | |
1505 | } | |
1506 | ||
1507 | int qcow2_zero_clusters(BlockDriverState *bs, uint64_t offset, int nb_sectors) | |
1508 | { | |
1509 | BDRVQcowState *s = bs->opaque; | |
1510 | unsigned int nb_clusters; | |
1511 | int ret; | |
1512 | ||
1513 | /* The zero flag is only supported by version 3 and newer */ | |
1514 | if (s->qcow_version < 3) { | |
1515 | return -ENOTSUP; | |
1516 | } | |
1517 | ||
1518 | /* Each L2 table is handled by its own loop iteration */ | |
1519 | nb_clusters = size_to_clusters(s, nb_sectors << BDRV_SECTOR_BITS); | |
1520 | ||
0b919fae KW |
1521 | s->cache_discards = true; |
1522 | ||
621f0589 KW |
1523 | while (nb_clusters > 0) { |
1524 | ret = zero_single_l2(bs, offset, nb_clusters); | |
1525 | if (ret < 0) { | |
0b919fae | 1526 | goto fail; |
621f0589 KW |
1527 | } |
1528 | ||
1529 | nb_clusters -= ret; | |
1530 | offset += (ret * s->cluster_size); | |
1531 | } | |
1532 | ||
0b919fae KW |
1533 | ret = 0; |
1534 | fail: | |
1535 | s->cache_discards = false; | |
1536 | qcow2_process_discards(bs, ret); | |
1537 | ||
1538 | return ret; | |
621f0589 | 1539 | } |
32b6444d HR |
1540 | |
1541 | /* | |
1542 | * Expands all zero clusters in a specific L1 table (or deallocates them, for | |
1543 | * non-backed non-pre-allocated zero clusters). | |
1544 | * | |
1545 | * expanded_clusters is a bitmap where every bit corresponds to one cluster in | |
1546 | * the image file; a bit gets set if the corresponding cluster has been used for | |
1547 | * zero expansion (i.e., has been filled with zeroes and is referenced from an | |
1548 | * L2 table). nb_clusters contains the total cluster count of the image file, | |
1549 | * i.e., the number of bits in expanded_clusters. | |
1550 | */ | |
1551 | static int expand_zero_clusters_in_l1(BlockDriverState *bs, uint64_t *l1_table, | |
e390cf5a HR |
1552 | int l1_size, uint8_t **expanded_clusters, |
1553 | uint64_t *nb_clusters) | |
32b6444d HR |
1554 | { |
1555 | BDRVQcowState *s = bs->opaque; | |
1556 | bool is_active_l1 = (l1_table == s->l1_table); | |
1557 | uint64_t *l2_table = NULL; | |
1558 | int ret; | |
1559 | int i, j; | |
1560 | ||
1561 | if (!is_active_l1) { | |
1562 | /* inactive L2 tables require a buffer to be stored in when loading | |
1563 | * them from disk */ | |
1564 | l2_table = qemu_blockalign(bs, s->cluster_size); | |
1565 | } | |
1566 | ||
1567 | for (i = 0; i < l1_size; i++) { | |
1568 | uint64_t l2_offset = l1_table[i] & L1E_OFFSET_MASK; | |
1569 | bool l2_dirty = false; | |
1570 | ||
1571 | if (!l2_offset) { | |
1572 | /* unallocated */ | |
1573 | continue; | |
1574 | } | |
1575 | ||
1576 | if (is_active_l1) { | |
1577 | /* get active L2 tables from cache */ | |
1578 | ret = qcow2_cache_get(bs, s->l2_table_cache, l2_offset, | |
1579 | (void **)&l2_table); | |
1580 | } else { | |
1581 | /* load inactive L2 tables from disk */ | |
1582 | ret = bdrv_read(bs->file, l2_offset / BDRV_SECTOR_SIZE, | |
1583 | (void *)l2_table, s->cluster_sectors); | |
1584 | } | |
1585 | if (ret < 0) { | |
1586 | goto fail; | |
1587 | } | |
1588 | ||
1589 | for (j = 0; j < s->l2_size; j++) { | |
1590 | uint64_t l2_entry = be64_to_cpu(l2_table[j]); | |
1591 | int64_t offset = l2_entry & L2E_OFFSET_MASK, cluster_index; | |
1592 | int cluster_type = qcow2_get_cluster_type(l2_entry); | |
320c7066 | 1593 | bool preallocated = offset != 0; |
32b6444d HR |
1594 | |
1595 | if (cluster_type == QCOW2_CLUSTER_NORMAL) { | |
1596 | cluster_index = offset >> s->cluster_bits; | |
e390cf5a HR |
1597 | assert((cluster_index >= 0) && (cluster_index < *nb_clusters)); |
1598 | if ((*expanded_clusters)[cluster_index / 8] & | |
32b6444d HR |
1599 | (1 << (cluster_index % 8))) { |
1600 | /* Probably a shared L2 table; this cluster was a zero | |
1601 | * cluster which has been expanded, its refcount | |
1602 | * therefore most likely requires an update. */ | |
1603 | ret = qcow2_update_cluster_refcount(bs, cluster_index, 1, | |
1604 | QCOW2_DISCARD_NEVER); | |
1605 | if (ret < 0) { | |
1606 | goto fail; | |
1607 | } | |
1608 | /* Since we just increased the refcount, the COPIED flag may | |
1609 | * no longer be set. */ | |
1610 | l2_table[j] = cpu_to_be64(l2_entry & ~QCOW_OFLAG_COPIED); | |
1611 | l2_dirty = true; | |
1612 | } | |
1613 | continue; | |
1614 | } | |
1615 | else if (qcow2_get_cluster_type(l2_entry) != QCOW2_CLUSTER_ZERO) { | |
1616 | continue; | |
1617 | } | |
1618 | ||
320c7066 | 1619 | if (!preallocated) { |
32b6444d HR |
1620 | if (!bs->backing_hd) { |
1621 | /* not backed; therefore we can simply deallocate the | |
1622 | * cluster */ | |
1623 | l2_table[j] = 0; | |
1624 | l2_dirty = true; | |
1625 | continue; | |
1626 | } | |
1627 | ||
1628 | offset = qcow2_alloc_clusters(bs, s->cluster_size); | |
1629 | if (offset < 0) { | |
1630 | ret = offset; | |
1631 | goto fail; | |
1632 | } | |
1633 | } | |
1634 | ||
231bb267 | 1635 | ret = qcow2_pre_write_overlap_check(bs, 0, offset, s->cluster_size); |
32b6444d | 1636 | if (ret < 0) { |
320c7066 HR |
1637 | if (!preallocated) { |
1638 | qcow2_free_clusters(bs, offset, s->cluster_size, | |
1639 | QCOW2_DISCARD_ALWAYS); | |
1640 | } | |
32b6444d HR |
1641 | goto fail; |
1642 | } | |
1643 | ||
1644 | ret = bdrv_write_zeroes(bs->file, offset / BDRV_SECTOR_SIZE, | |
aa7bfbff | 1645 | s->cluster_sectors, 0); |
32b6444d | 1646 | if (ret < 0) { |
320c7066 HR |
1647 | if (!preallocated) { |
1648 | qcow2_free_clusters(bs, offset, s->cluster_size, | |
1649 | QCOW2_DISCARD_ALWAYS); | |
1650 | } | |
32b6444d HR |
1651 | goto fail; |
1652 | } | |
1653 | ||
1654 | l2_table[j] = cpu_to_be64(offset | QCOW_OFLAG_COPIED); | |
1655 | l2_dirty = true; | |
1656 | ||
1657 | cluster_index = offset >> s->cluster_bits; | |
e390cf5a HR |
1658 | |
1659 | if (cluster_index >= *nb_clusters) { | |
1660 | uint64_t old_bitmap_size = (*nb_clusters + 7) / 8; | |
1661 | uint64_t new_bitmap_size; | |
1662 | /* The offset may lie beyond the old end of the underlying image | |
1663 | * file for growable files only */ | |
1664 | assert(bs->file->growable); | |
1665 | *nb_clusters = size_to_clusters(s, bs->file->total_sectors * | |
1666 | BDRV_SECTOR_SIZE); | |
1667 | new_bitmap_size = (*nb_clusters + 7) / 8; | |
1668 | *expanded_clusters = g_realloc(*expanded_clusters, | |
1669 | new_bitmap_size); | |
1670 | /* clear the newly allocated space */ | |
1671 | memset(&(*expanded_clusters)[old_bitmap_size], 0, | |
1672 | new_bitmap_size - old_bitmap_size); | |
1673 | } | |
1674 | ||
1675 | assert((cluster_index >= 0) && (cluster_index < *nb_clusters)); | |
1676 | (*expanded_clusters)[cluster_index / 8] |= 1 << (cluster_index % 8); | |
32b6444d HR |
1677 | } |
1678 | ||
1679 | if (is_active_l1) { | |
1680 | if (l2_dirty) { | |
1681 | qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table); | |
1682 | qcow2_cache_depends_on_flush(s->l2_table_cache); | |
1683 | } | |
1684 | ret = qcow2_cache_put(bs, s->l2_table_cache, (void **)&l2_table); | |
1685 | if (ret < 0) { | |
1686 | l2_table = NULL; | |
1687 | goto fail; | |
1688 | } | |
1689 | } else { | |
1690 | if (l2_dirty) { | |
231bb267 HR |
1691 | ret = qcow2_pre_write_overlap_check(bs, |
1692 | QCOW2_OL_INACTIVE_L2 | QCOW2_OL_ACTIVE_L2, l2_offset, | |
32b6444d HR |
1693 | s->cluster_size); |
1694 | if (ret < 0) { | |
1695 | goto fail; | |
1696 | } | |
1697 | ||
1698 | ret = bdrv_write(bs->file, l2_offset / BDRV_SECTOR_SIZE, | |
1699 | (void *)l2_table, s->cluster_sectors); | |
1700 | if (ret < 0) { | |
1701 | goto fail; | |
1702 | } | |
1703 | } | |
1704 | } | |
1705 | } | |
1706 | ||
1707 | ret = 0; | |
1708 | ||
1709 | fail: | |
1710 | if (l2_table) { | |
1711 | if (!is_active_l1) { | |
1712 | qemu_vfree(l2_table); | |
1713 | } else { | |
1714 | if (ret < 0) { | |
1715 | qcow2_cache_put(bs, s->l2_table_cache, (void **)&l2_table); | |
1716 | } else { | |
1717 | ret = qcow2_cache_put(bs, s->l2_table_cache, | |
1718 | (void **)&l2_table); | |
1719 | } | |
1720 | } | |
1721 | } | |
1722 | return ret; | |
1723 | } | |
1724 | ||
1725 | /* | |
1726 | * For backed images, expands all zero clusters on the image. For non-backed | |
1727 | * images, deallocates all non-pre-allocated zero clusters (and claims the | |
1728 | * allocation for pre-allocated ones). This is important for downgrading to a | |
1729 | * qcow2 version which doesn't yet support metadata zero clusters. | |
1730 | */ | |
1731 | int qcow2_expand_zero_clusters(BlockDriverState *bs) | |
1732 | { | |
1733 | BDRVQcowState *s = bs->opaque; | |
1734 | uint64_t *l1_table = NULL; | |
32b6444d HR |
1735 | uint64_t nb_clusters; |
1736 | uint8_t *expanded_clusters; | |
1737 | int ret; | |
1738 | int i, j; | |
1739 | ||
e390cf5a HR |
1740 | nb_clusters = size_to_clusters(s, bs->file->total_sectors * |
1741 | BDRV_SECTOR_SIZE); | |
32b6444d HR |
1742 | expanded_clusters = g_malloc0((nb_clusters + 7) / 8); |
1743 | ||
1744 | ret = expand_zero_clusters_in_l1(bs, s->l1_table, s->l1_size, | |
e390cf5a | 1745 | &expanded_clusters, &nb_clusters); |
32b6444d HR |
1746 | if (ret < 0) { |
1747 | goto fail; | |
1748 | } | |
1749 | ||
1750 | /* Inactive L1 tables may point to active L2 tables - therefore it is | |
1751 | * necessary to flush the L2 table cache before trying to access the L2 | |
1752 | * tables pointed to by inactive L1 entries (else we might try to expand | |
1753 | * zero clusters that have already been expanded); furthermore, it is also | |
1754 | * necessary to empty the L2 table cache, since it may contain tables which | |
1755 | * are now going to be modified directly on disk, bypassing the cache. | |
1756 | * qcow2_cache_empty() does both for us. */ | |
1757 | ret = qcow2_cache_empty(bs, s->l2_table_cache); | |
1758 | if (ret < 0) { | |
1759 | goto fail; | |
1760 | } | |
1761 | ||
1762 | for (i = 0; i < s->nb_snapshots; i++) { | |
1763 | int l1_sectors = (s->snapshots[i].l1_size * sizeof(uint64_t) + | |
1764 | BDRV_SECTOR_SIZE - 1) / BDRV_SECTOR_SIZE; | |
1765 | ||
1766 | l1_table = g_realloc(l1_table, l1_sectors * BDRV_SECTOR_SIZE); | |
1767 | ||
1768 | ret = bdrv_read(bs->file, s->snapshots[i].l1_table_offset / | |
1769 | BDRV_SECTOR_SIZE, (void *)l1_table, l1_sectors); | |
1770 | if (ret < 0) { | |
1771 | goto fail; | |
1772 | } | |
1773 | ||
1774 | for (j = 0; j < s->snapshots[i].l1_size; j++) { | |
1775 | be64_to_cpus(&l1_table[j]); | |
1776 | } | |
1777 | ||
1778 | ret = expand_zero_clusters_in_l1(bs, l1_table, s->snapshots[i].l1_size, | |
e390cf5a | 1779 | &expanded_clusters, &nb_clusters); |
32b6444d HR |
1780 | if (ret < 0) { |
1781 | goto fail; | |
1782 | } | |
1783 | } | |
1784 | ||
1785 | ret = 0; | |
1786 | ||
1787 | fail: | |
1788 | g_free(expanded_clusters); | |
1789 | g_free(l1_table); | |
1790 | return ret; | |
1791 | } |