xref: /illumos-kvm-cmd/block/qcow2.h (revision 68396ea9)
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"
29 
30 //#define DEBUG_ALLOC
31 //#define DEBUG_ALLOC2
32 //#define DEBUG_EXT
33 
34 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
35 #define QCOW_VERSION 2
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)
46 
47 #define REFCOUNT_SHIFT 1 /* refcount size is 2 bytes */
48 
49 #define MIN_CLUSTER_BITS 9
50 #define MAX_CLUSTER_BITS 21
51 
52 #define L2_CACHE_SIZE 16
53 
54 /* Must be at least 4 to cover all cases of refcount table growth */
55 #define REFCOUNT_CACHE_SIZE 4
56 
57 typedef struct QCowHeader {
58     uint32_t magic;
59     uint32_t version;
60     uint64_t backing_file_offset;
61     uint32_t backing_file_size;
62     uint32_t cluster_bits;
63     uint64_t size; /* in bytes */
64     uint32_t crypt_method;
65     uint32_t l1_size; /* XXX: save number of clusters instead ? */
66     uint64_t l1_table_offset;
67     uint64_t refcount_table_offset;
68     uint32_t refcount_table_clusters;
69     uint32_t nb_snapshots;
70     uint64_t snapshots_offset;
71 } QCowHeader;
72 
73 typedef struct QCowSnapshot {
74     uint64_t l1_table_offset;
75     uint32_t l1_size;
76     char *id_str;
77     char *name;
78     uint32_t vm_state_size;
79     uint32_t date_sec;
80     uint32_t date_nsec;
81     uint64_t vm_clock_nsec;
82 } QCowSnapshot;
83 
84 struct Qcow2Cache;
85 typedef struct Qcow2Cache Qcow2Cache;
86 
87 typedef struct BDRVQcowState {
88     int cluster_bits;
89     int cluster_size;
90     int cluster_sectors;
91     int l2_bits;
92     int l2_size;
93     int l1_size;
94     int l1_vm_state_index;
95     int csize_shift;
96     int csize_mask;
97     uint64_t cluster_offset_mask;
98     uint64_t l1_table_offset;
99     uint64_t *l1_table;
100 
101     Qcow2Cache* l2_table_cache;
102     Qcow2Cache* refcount_block_cache;
103 
104     uint8_t *cluster_cache;
105     uint8_t *cluster_data;
106     uint64_t cluster_cache_offset;
107     QLIST_HEAD(QCowClusterAlloc, QCowL2Meta) cluster_allocs;
108 
109     uint64_t *refcount_table;
110     uint64_t refcount_table_offset;
111     uint32_t refcount_table_size;
112     int64_t free_cluster_index;
113     int64_t free_byte_offset;
114 
115     uint32_t crypt_method; /* current crypt method, 0 if no key yet */
116     uint32_t crypt_method_header;
117     AES_KEY aes_encrypt_key;
118     AES_KEY aes_decrypt_key;
119     uint64_t snapshots_offset;
120     int snapshots_size;
121     int nb_snapshots;
122     QCowSnapshot *snapshots;
123 } BDRVQcowState;
124 
125 /* XXX: use std qcow open function ? */
126 typedef struct QCowCreateState {
127     int cluster_size;
128     int cluster_bits;
129     uint16_t *refcount_block;
130     uint64_t *refcount_table;
131     int64_t l1_table_offset;
132     int64_t refcount_table_offset;
133     int64_t refcount_block_offset;
134 } QCowCreateState;
135 
136 struct QCowAIOCB;
137 
138 /* XXX This could be private for qcow2-cluster.c */
139 typedef struct QCowL2Meta
140 {
141     uint64_t offset;
142     uint64_t cluster_offset;
143     int n_start;
144     int nb_available;
145     int nb_clusters;
146     struct QCowL2Meta *depends_on;
147     QLIST_HEAD(QCowAioDependencies, QCowAIOCB) dependent_requests;
148 
149     QLIST_ENTRY(QCowL2Meta) next_in_flight;
150 } QCowL2Meta;
151 
size_to_clusters(BDRVQcowState * s,int64_t size)152 static inline int size_to_clusters(BDRVQcowState *s, int64_t size)
153 {
154     return (size + (s->cluster_size - 1)) >> s->cluster_bits;
155 }
156 
size_to_l1(BDRVQcowState * s,int64_t size)157 static inline int size_to_l1(BDRVQcowState *s, int64_t size)
158 {
159     int shift = s->cluster_bits + s->l2_bits;
160     return (size + (1ULL << shift) - 1) >> shift;
161 }
162 
align_offset(int64_t offset,int n)163 static inline int64_t align_offset(int64_t offset, int n)
164 {
165     offset = (offset + n - 1) & ~(n - 1);
166     return offset;
167 }
168 
169 
170 // FIXME Need qcow2_ prefix to global functions
171 
172 /* qcow2.c functions */
173 int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov,
174                   int64_t sector_num, int nb_sectors);
175 
176 /* qcow2-refcount.c functions */
177 int qcow2_refcount_init(BlockDriverState *bs);
178 void qcow2_refcount_close(BlockDriverState *bs);
179 
180 int64_t qcow2_alloc_clusters(BlockDriverState *bs, int64_t size);
181 int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size);
182 void qcow2_free_clusters(BlockDriverState *bs,
183     int64_t offset, int64_t size);
184 void qcow2_free_any_clusters(BlockDriverState *bs,
185     uint64_t cluster_offset, int nb_clusters);
186 
187 void qcow2_create_refcount_update(QCowCreateState *s, int64_t offset,
188     int64_t size);
189 int qcow2_update_snapshot_refcount(BlockDriverState *bs,
190     int64_t l1_table_offset, int l1_size, int addend);
191 
192 int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res);
193 
194 /* qcow2-cluster.c functions */
195 int qcow2_grow_l1_table(BlockDriverState *bs, int min_size, bool exact_size);
196 void qcow2_l2_cache_reset(BlockDriverState *bs);
197 int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
198 void qcow2_encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
199                      uint8_t *out_buf, const uint8_t *in_buf,
200                      int nb_sectors, int enc,
201                      const AES_KEY *key);
202 
203 int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,
204     int *num, uint64_t *cluster_offset);
205 int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,
206     int n_start, int n_end, int *num, QCowL2Meta *m);
207 uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
208                                          uint64_t offset,
209                                          int compressed_size);
210 
211 int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m);
212 int qcow2_discard_clusters(BlockDriverState *bs, uint64_t offset,
213     int nb_sectors);
214 
215 /* qcow2-snapshot.c functions */
216 int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info);
217 int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id);
218 int qcow2_snapshot_delete(BlockDriverState *bs, const char *snapshot_id);
219 int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab);
220 int qcow2_snapshot_load_tmp(BlockDriverState *bs, const char *snapshot_name);
221 
222 void qcow2_free_snapshots(BlockDriverState *bs);
223 int qcow2_read_snapshots(BlockDriverState *bs);
224 
225 /* qcow2-cache.c functions */
226 Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables,
227     bool writethrough);
228 int qcow2_cache_destroy(BlockDriverState* bs, Qcow2Cache *c);
229 
230 void qcow2_cache_entry_mark_dirty(Qcow2Cache *c, void *table);
231 int qcow2_cache_flush(BlockDriverState *bs, Qcow2Cache *c);
232 int qcow2_cache_set_dependency(BlockDriverState *bs, Qcow2Cache *c,
233     Qcow2Cache *dependency);
234 void qcow2_cache_depends_on_flush(Qcow2Cache *c);
235 
236 int qcow2_cache_get(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
237     void **table);
238 int qcow2_cache_get_empty(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
239     void **table);
240 int qcow2_cache_put(BlockDriverState *bs, Qcow2Cache *c, void **table);
241 
242 #endif
243