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qcow2: Allow lazy refcounts to be enabled on the command line
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CommitLineData
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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
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28#include "block/aes.h"
29#include "block/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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SH
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;
6744cbab 175 int qcow_version;
74c4510a 176 bool use_lazy_refcounts;
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177
178 uint64_t incompatible_features;
179 uint64_t compatible_features;
180 uint64_t autoclear_features;
181
182 size_t unknown_header_fields_size;
183 void* unknown_header_fields;
75bab85c 184 QLIST_HEAD(, Qcow2UnknownHeaderExtension) unknown_header_ext;
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185} BDRVQcowState;
186
187/* XXX: use std qcow open function ? */
188typedef struct QCowCreateState {
189 int cluster_size;
190 int cluster_bits;
191 uint16_t *refcount_block;
192 uint64_t *refcount_table;
193 int64_t l1_table_offset;
194 int64_t refcount_table_offset;
195 int64_t refcount_block_offset;
196} QCowCreateState;
197
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198struct QCowAIOCB;
199
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200typedef struct Qcow2COWRegion {
201 /**
202 * Offset of the COW region in bytes from the start of the first cluster
203 * touched by the request.
204 */
205 uint64_t offset;
206
207 /** Number of sectors to copy */
208 int nb_sectors;
209} Qcow2COWRegion;
210
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211/**
212 * Describes an in-flight (part of a) write request that writes to clusters
213 * that are not referenced in their L2 table yet.
214 */
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215typedef struct QCowL2Meta
216{
1d3afd64 217 /** Guest offset of the first newly allocated cluster */
45aba42f 218 uint64_t offset;
1d3afd64 219
1d3afd64 220 /** Host offset of the first newly allocated cluster */
250196f1 221 uint64_t alloc_offset;
1d3afd64 222
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223 /**
224 * Number of sectors from the start of the first allocated cluster to
225 * the end of the (possibly shortened) request
226 */
45aba42f 227 int nb_available;
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228
229 /** Number of newly allocated clusters */
45aba42f 230 int nb_clusters;
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231
232 /**
233 * Requests that overlap with this allocation and wait to be restarted
234 * when the allocating request has completed.
235 */
68d100e9 236 CoQueue dependent_requests;
f214978a 237
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238 /**
239 * The COW Region between the start of the first allocated cluster and the
240 * area the guest actually writes to.
241 */
242 Qcow2COWRegion cow_start;
243
244 /**
245 * The COW Region between the area the guest actually writes to and the
246 * end of the last allocated cluster.
247 */
248 Qcow2COWRegion cow_end;
249
72cf2d4f 250 QLIST_ENTRY(QCowL2Meta) next_in_flight;
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251} QCowL2Meta;
252
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253enum {
254 QCOW2_CLUSTER_UNALLOCATED,
255 QCOW2_CLUSTER_NORMAL,
256 QCOW2_CLUSTER_COMPRESSED,
6377af48 257 QCOW2_CLUSTER_ZERO
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258};
259
260#define L1E_OFFSET_MASK 0x00ffffffffffff00ULL
261#define L2E_OFFSET_MASK 0x00ffffffffffff00ULL
262#define L2E_COMPRESSED_OFFSET_SIZE_MASK 0x3fffffffffffffffULL
263
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264#define REFT_OFFSET_MASK 0xffffffffffffff00ULL
265
45aba42f 266static inline int size_to_clusters(BDRVQcowState *s, int64_t size)
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267{
268 return (size + (s->cluster_size - 1)) >> s->cluster_bits;
269}
270
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271static inline int size_to_l1(BDRVQcowState *s, int64_t size)
272{
273 int shift = s->cluster_bits + s->l2_bits;
274 return (size + (1ULL << shift) - 1) >> shift;
275}
276
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277static inline int64_t align_offset(int64_t offset, int n)
278{
279 offset = (offset + n - 1) & ~(n - 1);
280 return offset;
281}
282
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283static inline int qcow2_get_cluster_type(uint64_t l2_entry)
284{
285 if (l2_entry & QCOW_OFLAG_COMPRESSED) {
286 return QCOW2_CLUSTER_COMPRESSED;
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287 } else if (l2_entry & QCOW_OFLAG_ZERO) {
288 return QCOW2_CLUSTER_ZERO;
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289 } else if (!(l2_entry & L2E_OFFSET_MASK)) {
290 return QCOW2_CLUSTER_UNALLOCATED;
291 } else {
292 return QCOW2_CLUSTER_NORMAL;
293 }
294}
295
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296/* Check whether refcounts are eager or lazy */
297static inline bool qcow2_need_accurate_refcounts(BDRVQcowState *s)
298{
299 return !(s->incompatible_features & QCOW2_INCOMPAT_DIRTY);
300}
c142442b 301
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302// FIXME Need qcow2_ prefix to global functions
303
304/* qcow2.c functions */
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305int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov,
306 int64_t sector_num, int nb_sectors);
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307
308int qcow2_mark_dirty(BlockDriverState *bs);
e24e49e6 309int qcow2_update_header(BlockDriverState *bs);
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310
311/* qcow2-refcount.c functions */
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312int qcow2_refcount_init(BlockDriverState *bs);
313void qcow2_refcount_close(BlockDriverState *bs);
f7d0fe02 314
ed6ccf0f 315int64_t qcow2_alloc_clusters(BlockDriverState *bs, int64_t size);
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316int qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset,
317 int nb_clusters);
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318int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size);
319void qcow2_free_clusters(BlockDriverState *bs,
45aba42f 320 int64_t offset, int64_t size);
ed6ccf0f 321void qcow2_free_any_clusters(BlockDriverState *bs,
45aba42f 322 uint64_t cluster_offset, int nb_clusters);
f7d0fe02 323
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324int qcow2_update_snapshot_refcount(BlockDriverState *bs,
325 int64_t l1_table_offset, int l1_size, int addend);
f7d0fe02 326
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327int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
328 BdrvCheckMode fix);
f7d0fe02 329
45aba42f 330/* qcow2-cluster.c functions */
72893756 331int qcow2_grow_l1_table(BlockDriverState *bs, int min_size, bool exact_size);
ed6ccf0f 332void qcow2_l2_cache_reset(BlockDriverState *bs);
66f82cee 333int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
ed6ccf0f 334void qcow2_encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
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335 uint8_t *out_buf, const uint8_t *in_buf,
336 int nb_sectors, int enc,
337 const AES_KEY *key);
338
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339int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,
340 int *num, uint64_t *cluster_offset);
f4f0d391 341int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,
f50f88b9 342 int n_start, int n_end, int *num, uint64_t *host_offset, QCowL2Meta **m);
ed6ccf0f 343uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
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344 uint64_t offset,
345 int compressed_size);
346
148da7ea 347int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m);
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348int qcow2_discard_clusters(BlockDriverState *bs, uint64_t offset,
349 int nb_sectors);
621f0589 350int qcow2_zero_clusters(BlockDriverState *bs, uint64_t offset, int nb_sectors);
45aba42f 351
c142442b 352/* qcow2-snapshot.c functions */
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353int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info);
354int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id);
355int qcow2_snapshot_delete(BlockDriverState *bs, const char *snapshot_id);
356int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab);
51ef6727 357int qcow2_snapshot_load_tmp(BlockDriverState *bs, const char *snapshot_name);
c142442b 358
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359void qcow2_free_snapshots(BlockDriverState *bs);
360int qcow2_read_snapshots(BlockDriverState *bs);
c142442b 361
49381094 362/* qcow2-cache.c functions */
6af4e9ea 363Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables);
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364int qcow2_cache_destroy(BlockDriverState* bs, Qcow2Cache *c);
365
366void qcow2_cache_entry_mark_dirty(Qcow2Cache *c, void *table);
367int qcow2_cache_flush(BlockDriverState *bs, Qcow2Cache *c);
368int qcow2_cache_set_dependency(BlockDriverState *bs, Qcow2Cache *c,
369 Qcow2Cache *dependency);
3de0a294 370void qcow2_cache_depends_on_flush(Qcow2Cache *c);
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371
372int qcow2_cache_get(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
373 void **table);
374int qcow2_cache_get_empty(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
375 void **table);
376int qcow2_cache_put(BlockDriverState *bs, Qcow2Cache *c, void **table);
377
f7d0fe02 378#endif