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qcow2: Round QCowL2Meta.offset down to cluster boundary
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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#ifndef BLOCK_QCOW2_H
26#define BLOCK_QCOW2_H
27
28#include "aes.h"
68d100e9 29#include "qemu-coroutine.h"
f7d0fe02 30
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31//#define DEBUG_ALLOC
32//#define DEBUG_ALLOC2
33//#define DEBUG_EXT
34
f7d0fe02 35#define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
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36
37#define QCOW_CRYPT_NONE 0
38#define QCOW_CRYPT_AES 1
39
40#define QCOW_MAX_CRYPT_CLUSTERS 32
41
42/* indicate that the refcount of the referenced cluster is exactly one. */
43#define QCOW_OFLAG_COPIED (1LL << 63)
44/* indicate that the cluster is compressed (they never have the copied flag) */
45#define QCOW_OFLAG_COMPRESSED (1LL << 62)
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46/* The cluster reads as all zeros */
47#define QCOW_OFLAG_ZERO (1LL << 0)
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48
49#define REFCOUNT_SHIFT 1 /* refcount size is 2 bytes */
50
51#define MIN_CLUSTER_BITS 9
80ee15a6 52#define MAX_CLUSTER_BITS 21
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53
54#define L2_CACHE_SIZE 16
55
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56/* Must be at least 4 to cover all cases of refcount table growth */
57#define REFCOUNT_CACHE_SIZE 4
58
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59#define DEFAULT_CLUSTER_SIZE 65536
60
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61typedef struct QCowHeader {
62 uint32_t magic;
63 uint32_t version;
64 uint64_t backing_file_offset;
65 uint32_t backing_file_size;
66 uint32_t cluster_bits;
67 uint64_t size; /* in bytes */
68 uint32_t crypt_method;
69 uint32_t l1_size; /* XXX: save number of clusters instead ? */
70 uint64_t l1_table_offset;
71 uint64_t refcount_table_offset;
72 uint32_t refcount_table_clusters;
73 uint32_t nb_snapshots;
74 uint64_t snapshots_offset;
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75
76 /* The following fields are only valid for version >= 3 */
77 uint64_t incompatible_features;
78 uint64_t compatible_features;
79 uint64_t autoclear_features;
80
81 uint32_t refcount_order;
82 uint32_t header_length;
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83} QCowHeader;
84
85typedef struct QCowSnapshot {
86 uint64_t l1_table_offset;
87 uint32_t l1_size;
88 char *id_str;
89 char *name;
90b27759 90 uint64_t disk_size;
c2c9a466 91 uint64_t vm_state_size;
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92 uint32_t date_sec;
93 uint32_t date_nsec;
94 uint64_t vm_clock_nsec;
95} QCowSnapshot;
96
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97struct Qcow2Cache;
98typedef struct Qcow2Cache Qcow2Cache;
99
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100typedef struct Qcow2UnknownHeaderExtension {
101 uint32_t magic;
102 uint32_t len;
103 QLIST_ENTRY(Qcow2UnknownHeaderExtension) next;
104 uint8_t data[];
105} Qcow2UnknownHeaderExtension;
106
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107enum {
108 QCOW2_FEAT_TYPE_INCOMPATIBLE = 0,
109 QCOW2_FEAT_TYPE_COMPATIBLE = 1,
110 QCOW2_FEAT_TYPE_AUTOCLEAR = 2,
111};
112
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113/* Incompatible feature bits */
114enum {
115 QCOW2_INCOMPAT_DIRTY_BITNR = 0,
116 QCOW2_INCOMPAT_DIRTY = 1 << QCOW2_INCOMPAT_DIRTY_BITNR,
117
118 QCOW2_INCOMPAT_MASK = QCOW2_INCOMPAT_DIRTY,
119};
120
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121/* Compatible feature bits */
122enum {
123 QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR = 0,
124 QCOW2_COMPAT_LAZY_REFCOUNTS = 1 << QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR,
125
126 QCOW2_COMPAT_FEAT_MASK = QCOW2_COMPAT_LAZY_REFCOUNTS,
127};
128
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129typedef struct Qcow2Feature {
130 uint8_t type;
131 uint8_t bit;
132 char name[46];
133} QEMU_PACKED Qcow2Feature;
134
f7d0fe02 135typedef struct BDRVQcowState {
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136 int cluster_bits;
137 int cluster_size;
138 int cluster_sectors;
139 int l2_bits;
140 int l2_size;
141 int l1_size;
142 int l1_vm_state_index;
143 int csize_shift;
144 int csize_mask;
145 uint64_t cluster_offset_mask;
146 uint64_t l1_table_offset;
147 uint64_t *l1_table;
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148
149 Qcow2Cache* l2_table_cache;
150 Qcow2Cache* refcount_block_cache;
151
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152 uint8_t *cluster_cache;
153 uint8_t *cluster_data;
154 uint64_t cluster_cache_offset;
72cf2d4f 155 QLIST_HEAD(QCowClusterAlloc, QCowL2Meta) cluster_allocs;
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156
157 uint64_t *refcount_table;
158 uint64_t refcount_table_offset;
159 uint32_t refcount_table_size;
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160 int64_t free_cluster_index;
161 int64_t free_byte_offset;
162
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163 CoMutex lock;
164
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165 uint32_t crypt_method; /* current crypt method, 0 if no key yet */
166 uint32_t crypt_method_header;
167 AES_KEY aes_encrypt_key;
168 AES_KEY aes_decrypt_key;
169 uint64_t snapshots_offset;
170 int snapshots_size;
171 int nb_snapshots;
172 QCowSnapshot *snapshots;
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173
174 int flags;
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175 int qcow_version;
176
177 uint64_t incompatible_features;
178 uint64_t compatible_features;
179 uint64_t autoclear_features;
180
181 size_t unknown_header_fields_size;
182 void* unknown_header_fields;
75bab85c 183 QLIST_HEAD(, Qcow2UnknownHeaderExtension) unknown_header_ext;
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184} BDRVQcowState;
185
186/* XXX: use std qcow open function ? */
187typedef struct QCowCreateState {
188 int cluster_size;
189 int cluster_bits;
190 uint16_t *refcount_block;
191 uint64_t *refcount_table;
192 int64_t l1_table_offset;
193 int64_t refcount_table_offset;
194 int64_t refcount_block_offset;
195} QCowCreateState;
196
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197struct QCowAIOCB;
198
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199/* XXX This could be private for qcow2-cluster.c */
200typedef struct QCowL2Meta
201{
1d3afd64 202 /** Guest offset of the first newly allocated cluster */
45aba42f 203 uint64_t offset;
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204
205 /** Host offset of the first cluster of the request */
148da7ea 206 uint64_t cluster_offset;
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207
208 /** Host offset of the first newly allocated cluster */
250196f1 209 uint64_t alloc_offset;
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210
211 /**
212 * Number of sectors between the start of the first allocated cluster and
213 * the area that the guest actually writes to.
214 */
45aba42f 215 int n_start;
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216
217 /**
218 * Number of sectors from the start of the first allocated cluster to
219 * the end of the (possibly shortened) request
220 */
45aba42f 221 int nb_available;
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222
223 /** Number of newly allocated clusters */
45aba42f 224 int nb_clusters;
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225
226 /**
227 * Requests that overlap with this allocation and wait to be restarted
228 * when the allocating request has completed.
229 */
68d100e9 230 CoQueue dependent_requests;
f214978a 231
72cf2d4f 232 QLIST_ENTRY(QCowL2Meta) next_in_flight;
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233} QCowL2Meta;
234
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235enum {
236 QCOW2_CLUSTER_UNALLOCATED,
237 QCOW2_CLUSTER_NORMAL,
238 QCOW2_CLUSTER_COMPRESSED,
6377af48 239 QCOW2_CLUSTER_ZERO
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240};
241
242#define L1E_OFFSET_MASK 0x00ffffffffffff00ULL
243#define L2E_OFFSET_MASK 0x00ffffffffffff00ULL
244#define L2E_COMPRESSED_OFFSET_SIZE_MASK 0x3fffffffffffffffULL
245
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246#define REFT_OFFSET_MASK 0xffffffffffffff00ULL
247
45aba42f 248static inline int size_to_clusters(BDRVQcowState *s, int64_t size)
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249{
250 return (size + (s->cluster_size - 1)) >> s->cluster_bits;
251}
252
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253static inline int size_to_l1(BDRVQcowState *s, int64_t size)
254{
255 int shift = s->cluster_bits + s->l2_bits;
256 return (size + (1ULL << shift) - 1) >> shift;
257}
258
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259static inline int64_t align_offset(int64_t offset, int n)
260{
261 offset = (offset + n - 1) & ~(n - 1);
262 return offset;
263}
264
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265static inline int qcow2_get_cluster_type(uint64_t l2_entry)
266{
267 if (l2_entry & QCOW_OFLAG_COMPRESSED) {
268 return QCOW2_CLUSTER_COMPRESSED;
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269 } else if (l2_entry & QCOW_OFLAG_ZERO) {
270 return QCOW2_CLUSTER_ZERO;
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271 } else if (!(l2_entry & L2E_OFFSET_MASK)) {
272 return QCOW2_CLUSTER_UNALLOCATED;
273 } else {
274 return QCOW2_CLUSTER_NORMAL;
275 }
276}
277
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278/* Check whether refcounts are eager or lazy */
279static inline bool qcow2_need_accurate_refcounts(BDRVQcowState *s)
280{
281 return !(s->incompatible_features & QCOW2_INCOMPAT_DIRTY);
282}
c142442b 283
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284// FIXME Need qcow2_ prefix to global functions
285
286/* qcow2.c functions */
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287int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov,
288 int64_t sector_num, int nb_sectors);
e24e49e6 289int qcow2_update_header(BlockDriverState *bs);
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290
291/* qcow2-refcount.c functions */
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292int qcow2_refcount_init(BlockDriverState *bs);
293void qcow2_refcount_close(BlockDriverState *bs);
f7d0fe02 294
ed6ccf0f 295int64_t qcow2_alloc_clusters(BlockDriverState *bs, int64_t size);
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296int qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset,
297 int nb_clusters);
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298int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size);
299void qcow2_free_clusters(BlockDriverState *bs,
45aba42f 300 int64_t offset, int64_t size);
ed6ccf0f 301void qcow2_free_any_clusters(BlockDriverState *bs,
45aba42f 302 uint64_t cluster_offset, int nb_clusters);
f7d0fe02 303
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304int qcow2_update_snapshot_refcount(BlockDriverState *bs,
305 int64_t l1_table_offset, int l1_size, int addend);
f7d0fe02 306
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307int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
308 BdrvCheckMode fix);
f7d0fe02 309
45aba42f 310/* qcow2-cluster.c functions */
72893756 311int qcow2_grow_l1_table(BlockDriverState *bs, int min_size, bool exact_size);
ed6ccf0f 312void qcow2_l2_cache_reset(BlockDriverState *bs);
66f82cee 313int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
ed6ccf0f 314void qcow2_encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
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315 uint8_t *out_buf, const uint8_t *in_buf,
316 int nb_sectors, int enc,
317 const AES_KEY *key);
318
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319int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,
320 int *num, uint64_t *cluster_offset);
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321int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,
322 int n_start, int n_end, int *num, QCowL2Meta *m);
ed6ccf0f 323uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
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324 uint64_t offset,
325 int compressed_size);
326
148da7ea 327int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m);
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328int qcow2_discard_clusters(BlockDriverState *bs, uint64_t offset,
329 int nb_sectors);
621f0589 330int qcow2_zero_clusters(BlockDriverState *bs, uint64_t offset, int nb_sectors);
45aba42f 331
c142442b 332/* qcow2-snapshot.c functions */
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333int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info);
334int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id);
335int qcow2_snapshot_delete(BlockDriverState *bs, const char *snapshot_id);
336int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab);
51ef6727 337int qcow2_snapshot_load_tmp(BlockDriverState *bs, const char *snapshot_name);
c142442b 338
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339void qcow2_free_snapshots(BlockDriverState *bs);
340int qcow2_read_snapshots(BlockDriverState *bs);
c142442b 341
49381094 342/* qcow2-cache.c functions */
6af4e9ea 343Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables);
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344int qcow2_cache_destroy(BlockDriverState* bs, Qcow2Cache *c);
345
346void qcow2_cache_entry_mark_dirty(Qcow2Cache *c, void *table);
347int qcow2_cache_flush(BlockDriverState *bs, Qcow2Cache *c);
348int qcow2_cache_set_dependency(BlockDriverState *bs, Qcow2Cache *c,
349 Qcow2Cache *dependency);
3de0a294 350void qcow2_cache_depends_on_flush(Qcow2Cache *c);
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351
352int qcow2_cache_get(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
353 void **table);
354int qcow2_cache_get_empty(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
355 void **table);
356int qcow2_cache_put(BlockDriverState *bs, Qcow2Cache *c, void **table);
357
f7d0fe02 358#endif