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