block/qcow2.h

   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 "crypto/block.h"
  29 #include "qemu/coroutine.h"
  30 #include "qemu/units.h"
  31
  32 //#define DEBUG_ALLOC
  33 //#define DEBUG_ALLOC2
  34 //#define DEBUG_EXT
  35
  36 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
  37
  38 #define QCOW_CRYPT_NONE 0
  39 #define QCOW_CRYPT_AES  1
  40 #define QCOW_CRYPT_LUKS 2
  41
  42 #define QCOW_MAX_CRYPT_CLUSTERS 32
  43 #define QCOW_MAX_SNAPSHOTS 65536
  44
  45 /* Field widths in qcow2 mean normal cluster offsets cannot reach
  46  * 64PB; depending on cluster size, compressed clusters can have a
  47  * smaller limit (64PB for up to 16k clusters, then ramps down to
  48  * 512TB for 2M clusters).  */
  49 #define QCOW_MAX_CLUSTER_OFFSET ((1ULL << 56) - 1)
  50
  51 /* 8 MB refcount table is enough for 2 PB images at 64k cluster size
  52  * (128 GB for 512 byte clusters, 2 EB for 2 MB clusters) */
  53 #define QCOW_MAX_REFTABLE_SIZE (8 * MiB)
  54
  55 /* 32 MB L1 table is enough for 2 PB images at 64k cluster size
  56  * (128 GB for 512 byte clusters, 2 EB for 2 MB clusters) */
  57 #define QCOW_MAX_L1_SIZE (32 * MiB)
  58
  59 /* Allow for an average of 1k per snapshot table entry, should be plenty of
  60  * space for snapshot names and IDs */
  61 #define QCOW_MAX_SNAPSHOTS_SIZE (1024 * QCOW_MAX_SNAPSHOTS)
  62
  63 /* Bitmap header extension constraints */
  64 #define QCOW2_MAX_BITMAPS 65535
  65 #define QCOW2_MAX_BITMAP_DIRECTORY_SIZE (1024 * QCOW2_MAX_BITMAPS)
  66
  67 /* indicate that the refcount of the referenced cluster is exactly one. */
  68 #define QCOW_OFLAG_COPIED     (1ULL << 63)
  69 /* indicate that the cluster is compressed (they never have the copied flag) */
  70 #define QCOW_OFLAG_COMPRESSED (1ULL << 62)
  71 /* The cluster reads as all zeros */
  72 #define QCOW_OFLAG_ZERO (1ULL << 0)
  73
  74 #define MIN_CLUSTER_BITS 9
  75 #define MAX_CLUSTER_BITS 21
  76
  77 /* Must be at least 2 to cover COW */
  78 #define MIN_L2_CACHE_SIZE 2 /* cache entries */
  79
  80 /* Must be at least 4 to cover all cases of refcount table growth */
  81 #define MIN_REFCOUNT_CACHE_SIZE 4 /* clusters */
  82
  83 #ifdef CONFIG_LINUX
  84 #define DEFAULT_L2_CACHE_MAX_SIZE (32 * MiB)
  85 #define DEFAULT_CACHE_CLEAN_INTERVAL 600  /* seconds */
  86 #else
  87 #define DEFAULT_L2_CACHE_MAX_SIZE (8 * MiB)
  88 /* Cache clean interval is currently available only on Linux, so must be 0 */
  89 #define DEFAULT_CACHE_CLEAN_INTERVAL 0
  90 #endif
  91
  92 #define DEFAULT_CLUSTER_SIZE 65536
  93
  94 #define QCOW2_OPT_DATA_FILE "data-file"
  95 #define QCOW2_OPT_LAZY_REFCOUNTS "lazy-refcounts"
  96 #define QCOW2_OPT_DISCARD_REQUEST "pass-discard-request"
  97 #define QCOW2_OPT_DISCARD_SNAPSHOT "pass-discard-snapshot"
  98 #define QCOW2_OPT_DISCARD_OTHER "pass-discard-other"
  99 #define QCOW2_OPT_OVERLAP "overlap-check"
 100 #define QCOW2_OPT_OVERLAP_TEMPLATE "overlap-check.template"
 101 #define QCOW2_OPT_OVERLAP_MAIN_HEADER "overlap-check.main-header"
 102 #define QCOW2_OPT_OVERLAP_ACTIVE_L1 "overlap-check.active-l1"
 103 #define QCOW2_OPT_OVERLAP_ACTIVE_L2 "overlap-check.active-l2"
 104 #define QCOW2_OPT_OVERLAP_REFCOUNT_TABLE "overlap-check.refcount-table"
 105 #define QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK "overlap-check.refcount-block"
 106 #define QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE "overlap-check.snapshot-table"
 107 #define QCOW2_OPT_OVERLAP_INACTIVE_L1 "overlap-check.inactive-l1"
 108 #define QCOW2_OPT_OVERLAP_INACTIVE_L2 "overlap-check.inactive-l2"
 109 #define QCOW2_OPT_OVERLAP_BITMAP_DIRECTORY "overlap-check.bitmap-directory"
 110 #define QCOW2_OPT_CACHE_SIZE "cache-size"
 111 #define QCOW2_OPT_L2_CACHE_SIZE "l2-cache-size"
 112 #define QCOW2_OPT_L2_CACHE_ENTRY_SIZE "l2-cache-entry-size"
 113 #define QCOW2_OPT_REFCOUNT_CACHE_SIZE "refcount-cache-size"
 114 #define QCOW2_OPT_CACHE_CLEAN_INTERVAL "cache-clean-interval"
 115
 116 typedef struct QCowHeader {
 117     uint32_t magic;
 118     uint32_t version;
 119     uint64_t backing_file_offset;
 120     uint32_t backing_file_size;
 121     uint32_t cluster_bits;
 122     uint64_t size; /* in bytes */
 123     uint32_t crypt_method;
 124     uint32_t l1_size; /* XXX: save number of clusters instead ? */
 125     uint64_t l1_table_offset;
 126     uint64_t refcount_table_offset;
 127     uint32_t refcount_table_clusters;
 128     uint32_t nb_snapshots;
 129     uint64_t snapshots_offset;
 130
 131     /* The following fields are only valid for version >= 3 */
 132     uint64_t incompatible_features;
 133     uint64_t compatible_features;
 134     uint64_t autoclear_features;
 135
 136     uint32_t refcount_order;
 137     uint32_t header_length;
 138 } QEMU_PACKED QCowHeader;
 139
 140 typedef struct QEMU_PACKED QCowSnapshotHeader {
 141     /* header is 8 byte aligned */
 142     uint64_t l1_table_offset;
 143
 144     uint32_t l1_size;
 145     uint16_t id_str_size;
 146     uint16_t name_size;
 147
 148     uint32_t date_sec;
 149     uint32_t date_nsec;
 150
 151     uint64_t vm_clock_nsec;
 152
 153     uint32_t vm_state_size;
 154     uint32_t extra_data_size; /* for extension */
 155     /* extra data follows */
 156     /* id_str follows */
 157     /* name follows  */
 158 } QCowSnapshotHeader;
 159
 160 typedef struct QEMU_PACKED QCowSnapshotExtraData {
 161     uint64_t vm_state_size_large;
 162     uint64_t disk_size;
 163 } QCowSnapshotExtraData;
 164
 165
 166 typedef struct QCowSnapshot {
 167     uint64_t l1_table_offset;
 168     uint32_t l1_size;
 169     char *id_str;
 170     char *name;
 171     uint64_t disk_size;
 172     uint64_t vm_state_size;
 173     uint32_t date_sec;
 174     uint32_t date_nsec;
 175     uint64_t vm_clock_nsec;
 176 } QCowSnapshot;
 177
 178 struct Qcow2Cache;
 179 typedef struct Qcow2Cache Qcow2Cache;
 180
 181 typedef struct Qcow2CryptoHeaderExtension {
 182     uint64_t offset;
 183     uint64_t length;
 184 } QEMU_PACKED Qcow2CryptoHeaderExtension;
 185
 186 typedef struct Qcow2UnknownHeaderExtension {
 187     uint32_t magic;
 188     uint32_t len;
 189     QLIST_ENTRY(Qcow2UnknownHeaderExtension) next;
 190     uint8_t data[];
 191 } Qcow2UnknownHeaderExtension;
 192
 193 enum {
 194     QCOW2_FEAT_TYPE_INCOMPATIBLE    = 0,
 195     QCOW2_FEAT_TYPE_COMPATIBLE      = 1,
 196     QCOW2_FEAT_TYPE_AUTOCLEAR       = 2,
 197 };
 198
 199 /* Incompatible feature bits */
 200 enum {
 201     QCOW2_INCOMPAT_DIRTY_BITNR      = 0,
 202     QCOW2_INCOMPAT_CORRUPT_BITNR    = 1,
 203     QCOW2_INCOMPAT_DATA_FILE_BITNR  = 2,
 204     QCOW2_INCOMPAT_DIRTY            = 1 << QCOW2_INCOMPAT_DIRTY_BITNR,
 205     QCOW2_INCOMPAT_CORRUPT          = 1 << QCOW2_INCOMPAT_CORRUPT_BITNR,
 206     QCOW2_INCOMPAT_DATA_FILE        = 1 << QCOW2_INCOMPAT_DATA_FILE_BITNR,
 207
 208     QCOW2_INCOMPAT_MASK             = QCOW2_INCOMPAT_DIRTY
 209                                     | QCOW2_INCOMPAT_CORRUPT
 210                                     | QCOW2_INCOMPAT_DATA_FILE,
 211 };
 212
 213 /* Compatible feature bits */
 214 enum {
 215     QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR = 0,
 216     QCOW2_COMPAT_LAZY_REFCOUNTS       = 1 << QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR,
 217
 218     QCOW2_COMPAT_FEAT_MASK            = QCOW2_COMPAT_LAZY_REFCOUNTS,
 219 };
 220
 221 /* Autoclear feature bits */
 222 enum {
 223     QCOW2_AUTOCLEAR_BITMAPS_BITNR       = 0,
 224     QCOW2_AUTOCLEAR_DATA_FILE_RAW_BITNR = 1,
 225     QCOW2_AUTOCLEAR_BITMAPS             = 1 << QCOW2_AUTOCLEAR_BITMAPS_BITNR,
 226     QCOW2_AUTOCLEAR_DATA_FILE_RAW       = 1 << QCOW2_AUTOCLEAR_DATA_FILE_RAW_BITNR,
 227
 228     QCOW2_AUTOCLEAR_MASK                = QCOW2_AUTOCLEAR_BITMAPS,
 229 };
 230
 231 enum qcow2_discard_type {
 232     QCOW2_DISCARD_NEVER = 0,
 233     QCOW2_DISCARD_ALWAYS,
 234     QCOW2_DISCARD_REQUEST,
 235     QCOW2_DISCARD_SNAPSHOT,
 236     QCOW2_DISCARD_OTHER,
 237     QCOW2_DISCARD_MAX
 238 };
 239
 240 typedef struct Qcow2Feature {
 241     uint8_t type;
 242     uint8_t bit;
 243     char    name[46];
 244 } QEMU_PACKED Qcow2Feature;
 245
 246 typedef struct Qcow2DiscardRegion {
 247     BlockDriverState *bs;
 248     uint64_t offset;
 249     uint64_t bytes;
 250     QTAILQ_ENTRY(Qcow2DiscardRegion) next;
 251 } Qcow2DiscardRegion;
 252
 253 typedef uint64_t Qcow2GetRefcountFunc(const void *refcount_array,
 254                                       uint64_t index);
 255 typedef void Qcow2SetRefcountFunc(void *refcount_array,
 256                                   uint64_t index, uint64_t value);
 257
 258 typedef struct Qcow2BitmapHeaderExt {
 259     uint32_t nb_bitmaps;
 260     uint32_t reserved32;
 261     uint64_t bitmap_directory_size;
 262     uint64_t bitmap_directory_offset;
 263 } QEMU_PACKED Qcow2BitmapHeaderExt;
 264
 265 typedef struct BDRVQcow2State {
 266     int cluster_bits;
 267     int cluster_size;
 268     int cluster_sectors;
 269     int l2_slice_size;
 270     int l2_bits;
 271     int l2_size;
 272     int l1_size;
 273     int l1_vm_state_index;
 274     int refcount_block_bits;
 275     int refcount_block_size;
 276     int csize_shift;
 277     int csize_mask;
 278     uint64_t cluster_offset_mask;
 279     uint64_t l1_table_offset;
 280     uint64_t *l1_table;
 281
 282     Qcow2Cache* l2_table_cache;
 283     Qcow2Cache* refcount_block_cache;
 284     QEMUTimer *cache_clean_timer;
 285     unsigned cache_clean_interval;
 286
 287     uint8_t *cluster_cache;
 288     uint8_t *cluster_data;
 289     uint64_t cluster_cache_offset;
 290     QLIST_HEAD(, QCowL2Meta) cluster_allocs;
 291
 292     uint64_t *refcount_table;
 293     uint64_t refcount_table_offset;
 294     uint32_t refcount_table_size;
 295     uint32_t max_refcount_table_index; /* Last used entry in refcount_table */
 296     uint64_t free_cluster_index;
 297     uint64_t free_byte_offset;
 298
 299     CoMutex lock;
 300
 301     Qcow2CryptoHeaderExtension crypto_header; /* QCow2 header extension */
 302     QCryptoBlockOpenOptions *crypto_opts; /* Disk encryption runtime options */
 303     QCryptoBlock *crypto; /* Disk encryption format driver */
 304     bool crypt_physical_offset; /* Whether to use virtual or physical offset
 305                                    for encryption initialization vector tweak */
 306     uint32_t crypt_method_header;
 307     uint64_t snapshots_offset;
 308     int snapshots_size;
 309     unsigned int nb_snapshots;
 310     QCowSnapshot *snapshots;
 311
 312     uint32_t nb_bitmaps;
 313     uint64_t bitmap_directory_size;
 314     uint64_t bitmap_directory_offset;
 315
 316     int flags;
 317     int qcow_version;
 318     bool use_lazy_refcounts;
 319     int refcount_order;
 320     int refcount_bits;
 321     uint64_t refcount_max;
 322
 323     Qcow2GetRefcountFunc *get_refcount;
 324     Qcow2SetRefcountFunc *set_refcount;
 325
 326     bool discard_passthrough[QCOW2_DISCARD_MAX];
 327
 328     int overlap_check; /* bitmask of Qcow2MetadataOverlap values */
 329     bool signaled_corruption;
 330
 331     uint64_t incompatible_features;
 332     uint64_t compatible_features;
 333     uint64_t autoclear_features;
 334
 335     size_t unknown_header_fields_size;
 336     void* unknown_header_fields;
 337     QLIST_HEAD(, Qcow2UnknownHeaderExtension) unknown_header_ext;
 338     QTAILQ_HEAD (, Qcow2DiscardRegion) discards;
 339     bool cache_discards;
 340
 341     /* Backing file path and format as stored in the image (this is not the
 342      * effective path/format, which may be the result of a runtime option
 343      * override) */
 344     char *image_backing_file;
 345     char *image_backing_format;
 346     char *image_data_file;
 347
 348     CoQueue compress_wait_queue;
 349     int nb_compress_threads;
 350
 351     BdrvChild *data_file;
 352 } BDRVQcow2State;
 353
 354 typedef struct Qcow2COWRegion {
 355     /**
 356      * Offset of the COW region in bytes from the start of the first cluster
 357      * touched by the request.
 358      */
 359     unsigned    offset;
 360
 361     /** Number of bytes to copy */
 362     unsigned    nb_bytes;
 363 } Qcow2COWRegion;
 364
 365 /**
 366  * Describes an in-flight (part of a) write request that writes to clusters
 367  * that are not referenced in their L2 table yet.
 368  */
 369 typedef struct QCowL2Meta
 370 {
 371     /** Guest offset of the first newly allocated cluster */
 372     uint64_t offset;
 373
 374     /** Host offset of the first newly allocated cluster */
 375     uint64_t alloc_offset;
 376
 377     /** Number of newly allocated clusters */
 378     int nb_clusters;
 379
 380     /** Do not free the old clusters */
 381     bool keep_old_clusters;
 382
 383     /**
 384      * Requests that overlap with this allocation and wait to be restarted
 385      * when the allocating request has completed.
 386      */
 387     CoQueue dependent_requests;
 388
 389     /**
 390      * The COW Region between the start of the first allocated cluster and the
 391      * area the guest actually writes to.
 392      */
 393     Qcow2COWRegion cow_start;
 394
 395     /**
 396      * The COW Region between the area the guest actually writes to and the
 397      * end of the last allocated cluster.
 398      */
 399     Qcow2COWRegion cow_end;
 400
 401     /**
 402      * The I/O vector with the data from the actual guest write request.
 403      * If non-NULL, this is meant to be merged together with the data
 404      * from @cow_start and @cow_end into one single write operation.
 405      */
 406     QEMUIOVector *data_qiov;
 407
 408     /** Pointer to next L2Meta of the same write request */
 409     struct QCowL2Meta *next;
 410
 411     QLIST_ENTRY(QCowL2Meta) next_in_flight;
 412 } QCowL2Meta;
 413
 414 typedef enum QCow2ClusterType {
 415     QCOW2_CLUSTER_UNALLOCATED,
 416     QCOW2_CLUSTER_ZERO_PLAIN,
 417     QCOW2_CLUSTER_ZERO_ALLOC,
 418     QCOW2_CLUSTER_NORMAL,
 419     QCOW2_CLUSTER_COMPRESSED,
 420 } QCow2ClusterType;
 421
 422 typedef enum QCow2MetadataOverlap {
 423     QCOW2_OL_MAIN_HEADER_BITNR      = 0,
 424     QCOW2_OL_ACTIVE_L1_BITNR        = 1,
 425     QCOW2_OL_ACTIVE_L2_BITNR        = 2,
 426     QCOW2_OL_REFCOUNT_TABLE_BITNR   = 3,
 427     QCOW2_OL_REFCOUNT_BLOCK_BITNR   = 4,
 428     QCOW2_OL_SNAPSHOT_TABLE_BITNR   = 5,
 429     QCOW2_OL_INACTIVE_L1_BITNR      = 6,
 430     QCOW2_OL_INACTIVE_L2_BITNR      = 7,
 431     QCOW2_OL_BITMAP_DIRECTORY_BITNR = 8,
 432
 433     QCOW2_OL_MAX_BITNR              = 9,
 434
 435     QCOW2_OL_NONE             = 0,
 436     QCOW2_OL_MAIN_HEADER      = (1 << QCOW2_OL_MAIN_HEADER_BITNR),
 437     QCOW2_OL_ACTIVE_L1        = (1 << QCOW2_OL_ACTIVE_L1_BITNR),
 438     QCOW2_OL_ACTIVE_L2        = (1 << QCOW2_OL_ACTIVE_L2_BITNR),
 439     QCOW2_OL_REFCOUNT_TABLE   = (1 << QCOW2_OL_REFCOUNT_TABLE_BITNR),
 440     QCOW2_OL_REFCOUNT_BLOCK   = (1 << QCOW2_OL_REFCOUNT_BLOCK_BITNR),
 441     QCOW2_OL_SNAPSHOT_TABLE   = (1 << QCOW2_OL_SNAPSHOT_TABLE_BITNR),
 442     QCOW2_OL_INACTIVE_L1      = (1 << QCOW2_OL_INACTIVE_L1_BITNR),
 443     /* NOTE: Checking overlaps with inactive L2 tables will result in bdrv
 444      * reads. */
 445     QCOW2_OL_INACTIVE_L2      = (1 << QCOW2_OL_INACTIVE_L2_BITNR),
 446     QCOW2_OL_BITMAP_DIRECTORY = (1 << QCOW2_OL_BITMAP_DIRECTORY_BITNR),
 447 } QCow2MetadataOverlap;
 448
 449 /* Perform all overlap checks which can be done in constant time */
 450 #define QCOW2_OL_CONSTANT \
 451     (QCOW2_OL_MAIN_HEADER | QCOW2_OL_ACTIVE_L1 | QCOW2_OL_REFCOUNT_TABLE | \
 452      QCOW2_OL_SNAPSHOT_TABLE | QCOW2_OL_BITMAP_DIRECTORY)
 453
 454 /* Perform all overlap checks which don't require disk access */
 455 #define QCOW2_OL_CACHED \
 456     (QCOW2_OL_CONSTANT | QCOW2_OL_ACTIVE_L2 | QCOW2_OL_REFCOUNT_BLOCK | \
 457      QCOW2_OL_INACTIVE_L1)
 458
 459 /* Perform all overlap checks */
 460 #define QCOW2_OL_ALL \
 461     (QCOW2_OL_CACHED | QCOW2_OL_INACTIVE_L2)
 462
 463 #define L1E_OFFSET_MASK 0x00fffffffffffe00ULL
 464 #define L2E_OFFSET_MASK 0x00fffffffffffe00ULL
 465 #define L2E_COMPRESSED_OFFSET_SIZE_MASK 0x3fffffffffffffffULL
 466
 467 #define REFT_OFFSET_MASK 0xfffffffffffffe00ULL
 468
 469 #define INV_OFFSET (-1ULL)
 470
 471 static inline bool has_data_file(BlockDriverState *bs)
 472 {
 473     BDRVQcow2State *s = bs->opaque;
 474     return (s->data_file != bs->file);
 475 }
 476
 477 static inline int64_t start_of_cluster(BDRVQcow2State *s, int64_t offset)
 478 {
 479     return offset & ~(s->cluster_size - 1);
 480 }
 481
 482 static inline int64_t offset_into_cluster(BDRVQcow2State *s, int64_t offset)
 483 {
 484     return offset & (s->cluster_size - 1);
 485 }
 486
 487 static inline uint64_t size_to_clusters(BDRVQcow2State *s, uint64_t size)
 488 {
 489     return (size + (s->cluster_size - 1)) >> s->cluster_bits;
 490 }
 491
 492 static inline int64_t size_to_l1(BDRVQcow2State *s, int64_t size)
 493 {
 494     int shift = s->cluster_bits + s->l2_bits;
 495     return (size + (1ULL << shift) - 1) >> shift;
 496 }
 497
 498 static inline int offset_to_l1_index(BDRVQcow2State *s, uint64_t offset)
 499 {
 500     return offset >> (s->l2_bits + s->cluster_bits);
 501 }
 502
 503 static inline int offset_to_l2_index(BDRVQcow2State *s, int64_t offset)
 504 {
 505     return (offset >> s->cluster_bits) & (s->l2_size - 1);
 506 }
 507
 508 static inline int offset_to_l2_slice_index(BDRVQcow2State *s, int64_t offset)
 509 {
 510     return (offset >> s->cluster_bits) & (s->l2_slice_size - 1);
 511 }
 512
 513 static inline int64_t qcow2_vm_state_offset(BDRVQcow2State *s)
 514 {
 515     return (int64_t)s->l1_vm_state_index << (s->cluster_bits + s->l2_bits);
 516 }
 517
 518 static inline QCow2ClusterType qcow2_get_cluster_type(BlockDriverState *bs,
 519                                                       uint64_t l2_entry)
 520 {
 521     if (l2_entry & QCOW_OFLAG_COMPRESSED) {
 522         return QCOW2_CLUSTER_COMPRESSED;
 523     } else if (l2_entry & QCOW_OFLAG_ZERO) {
 524         if (l2_entry & L2E_OFFSET_MASK) {
 525             return QCOW2_CLUSTER_ZERO_ALLOC;
 526         }
 527         return QCOW2_CLUSTER_ZERO_PLAIN;
 528     } else if (!(l2_entry & L2E_OFFSET_MASK)) {
 529         /* Offset 0 generally means unallocated, but it is ambiguous with
 530          * external data files because 0 is a valid offset there. However, all
 531          * clusters in external data files always have refcount 1, so we can
 532          * rely on QCOW_OFLAG_COPIED to disambiguate. */
 533         if (has_data_file(bs) && (l2_entry & QCOW_OFLAG_COPIED)) {
 534             return QCOW2_CLUSTER_NORMAL;
 535         } else {
 536             return QCOW2_CLUSTER_UNALLOCATED;
 537         }
 538     } else {
 539         return QCOW2_CLUSTER_NORMAL;
 540     }
 541 }
 542
 543 /* Check whether refcounts are eager or lazy */
 544 static inline bool qcow2_need_accurate_refcounts(BDRVQcow2State *s)
 545 {
 546     return !(s->incompatible_features & QCOW2_INCOMPAT_DIRTY);
 547 }
 548
 549 static inline uint64_t l2meta_cow_start(QCowL2Meta *m)
 550 {
 551     return m->offset + m->cow_start.offset;
 552 }
 553
 554 static inline uint64_t l2meta_cow_end(QCowL2Meta *m)
 555 {
 556     return m->offset + m->cow_end.offset + m->cow_end.nb_bytes;
 557 }
 558
 559 static inline uint64_t refcount_diff(uint64_t r1, uint64_t r2)
 560 {
 561     return r1 > r2 ? r1 - r2 : r2 - r1;
 562 }
 563
 564 static inline
 565 uint32_t offset_to_reftable_index(BDRVQcow2State *s, uint64_t offset)
 566 {
 567     return offset >> (s->refcount_block_bits + s->cluster_bits);
 568 }
 569
 570 /* qcow2.c functions */
 571 int64_t qcow2_refcount_metadata_size(int64_t clusters, size_t cluster_size,
 572                                      int refcount_order, bool generous_increase,
 573                                      uint64_t *refblock_count);
 574
 575 int qcow2_mark_dirty(BlockDriverState *bs);
 576 int qcow2_mark_corrupt(BlockDriverState *bs);
 577 int qcow2_mark_consistent(BlockDriverState *bs);
 578 int qcow2_update_header(BlockDriverState *bs);
 579
 580 void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset,
 581                              int64_t size, const char *message_format, ...)
 582                              GCC_FMT_ATTR(5, 6);
 583
 584 int qcow2_validate_table(BlockDriverState *bs, uint64_t offset,
 585                          uint64_t entries, size_t entry_len,
 586                          int64_t max_size_bytes, const char *table_name,
 587                          Error **errp);
 588
 589 /* qcow2-refcount.c functions */
 590 int qcow2_refcount_init(BlockDriverState *bs);
 591 void qcow2_refcount_close(BlockDriverState *bs);
 592
 593 int qcow2_get_refcount(BlockDriverState *bs, int64_t cluster_index,
 594                        uint64_t *refcount);
 595
 596 int qcow2_update_cluster_refcount(BlockDriverState *bs, int64_t cluster_index,
 597                                   uint64_t addend, bool decrease,
 598                                   enum qcow2_discard_type type);
 599
 600 int64_t qcow2_refcount_area(BlockDriverState *bs, uint64_t offset,
 601                             uint64_t additional_clusters, bool exact_size,
 602                             int new_refblock_index,
 603                             uint64_t new_refblock_offset);
 604
 605 int64_t qcow2_alloc_clusters(BlockDriverState *bs, uint64_t size);
 606 int64_t qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset,
 607                                 int64_t nb_clusters);
 608 int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size);
 609 void qcow2_free_clusters(BlockDriverState *bs,
 610                           int64_t offset, int64_t size,
 611                           enum qcow2_discard_type type);
 612 void qcow2_free_any_clusters(BlockDriverState *bs, uint64_t l2_entry,
 613                              int nb_clusters, enum qcow2_discard_type type);
 614
 615 int qcow2_update_snapshot_refcount(BlockDriverState *bs,
 616     int64_t l1_table_offset, int l1_size, int addend);
 617
 618 int coroutine_fn qcow2_flush_caches(BlockDriverState *bs);
 619 int coroutine_fn qcow2_write_caches(BlockDriverState *bs);
 620 int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
 621                           BdrvCheckMode fix);
 622
 623 void qcow2_process_discards(BlockDriverState *bs, int ret);
 624
 625 int qcow2_check_metadata_overlap(BlockDriverState *bs, int ign, int64_t offset,
 626                                  int64_t size);
 627 int qcow2_pre_write_overlap_check(BlockDriverState *bs, int ign, int64_t offset,
 628                                   int64_t size, bool data_file);
 629 int qcow2_inc_refcounts_imrt(BlockDriverState *bs, BdrvCheckResult *res,
 630                              void **refcount_table,
 631                              int64_t *refcount_table_size,
 632                              int64_t offset, int64_t size);
 633
 634 int qcow2_change_refcount_order(BlockDriverState *bs, int refcount_order,
 635                                 BlockDriverAmendStatusCB *status_cb,
 636                                 void *cb_opaque, Error **errp);
 637 int qcow2_shrink_reftable(BlockDriverState *bs);
 638 int64_t qcow2_get_last_cluster(BlockDriverState *bs, int64_t size);
 639
 640 /* qcow2-cluster.c functions */
 641 int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size,
 642                         bool exact_size);
 643 int qcow2_shrink_l1_table(BlockDriverState *bs, uint64_t max_size);
 644 int qcow2_write_l1_entry(BlockDriverState *bs, int l1_index);
 645 int qcow2_encrypt_sectors(BDRVQcow2State *s, int64_t sector_num,
 646                           uint8_t *buf, int nb_sectors, bool enc, Error **errp);
 647
 648 int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,
 649                              unsigned int *bytes, uint64_t *cluster_offset);
 650 int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,
 651                                unsigned int *bytes, uint64_t *host_offset,
 652                                QCowL2Meta **m);
 653 int qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
 654                                           uint64_t offset,
 655                                           int compressed_size,
 656                                           uint64_t *host_offset);
 657
 658 int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m);
 659 void qcow2_alloc_cluster_abort(BlockDriverState *bs, QCowL2Meta *m);
 660 int qcow2_cluster_discard(BlockDriverState *bs, uint64_t offset,
 661                           uint64_t bytes, enum qcow2_discard_type type,
 662                           bool full_discard);
 663 int qcow2_cluster_zeroize(BlockDriverState *bs, uint64_t offset,
 664                           uint64_t bytes, int flags);
 665
 666 int qcow2_expand_zero_clusters(BlockDriverState *bs,
 667                                BlockDriverAmendStatusCB *status_cb,
 668                                void *cb_opaque);
 669
 670 /* qcow2-snapshot.c functions */
 671 int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info);
 672 int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id);
 673 int qcow2_snapshot_delete(BlockDriverState *bs,
 674                           const char *snapshot_id,
 675                           const char *name,
 676                           Error **errp);
 677 int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab);
 678 int qcow2_snapshot_load_tmp(BlockDriverState *bs,
 679                             const char *snapshot_id,
 680                             const char *name,
 681                             Error **errp);
 682
 683 void qcow2_free_snapshots(BlockDriverState *bs);
 684 int qcow2_read_snapshots(BlockDriverState *bs);
 685
 686 /* qcow2-cache.c functions */
 687 Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables,
 688                                unsigned table_size);
 689 int qcow2_cache_destroy(Qcow2Cache *c);
 690
 691 void qcow2_cache_entry_mark_dirty(Qcow2Cache *c, void *table);
 692 int qcow2_cache_flush(BlockDriverState *bs, Qcow2Cache *c);
 693 int qcow2_cache_write(BlockDriverState *bs, Qcow2Cache *c);
 694 int qcow2_cache_set_dependency(BlockDriverState *bs, Qcow2Cache *c,
 695     Qcow2Cache *dependency);
 696 void qcow2_cache_depends_on_flush(Qcow2Cache *c);
 697
 698 void qcow2_cache_clean_unused(Qcow2Cache *c);
 699 int qcow2_cache_empty(BlockDriverState *bs, Qcow2Cache *c);
 700
 701 int qcow2_cache_get(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
 702     void **table);
 703 int qcow2_cache_get_empty(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
 704     void **table);
 705 void qcow2_cache_put(Qcow2Cache *c, void **table);
 706 void *qcow2_cache_is_table_offset(Qcow2Cache *c, uint64_t offset);
 707 void qcow2_cache_discard(Qcow2Cache *c, void *table);
 708
 709 /* qcow2-bitmap.c functions */
 710 int qcow2_check_bitmaps_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
 711                                   void **refcount_table,
 712                                   int64_t *refcount_table_size);
 713 bool qcow2_load_dirty_bitmaps(BlockDriverState *bs, Error **errp);
 714 Qcow2BitmapInfoList *qcow2_get_bitmap_info_list(BlockDriverState *bs,
 715                                                 Error **errp);
 716 int qcow2_reopen_bitmaps_rw_hint(BlockDriverState *bs, bool *header_updated,
 717                                  Error **errp);
 718 int qcow2_reopen_bitmaps_rw(BlockDriverState *bs, Error **errp);
 719 void qcow2_store_persistent_dirty_bitmaps(BlockDriverState *bs, Error **errp);
 720 int qcow2_reopen_bitmaps_ro(BlockDriverState *bs, Error **errp);
 721 bool qcow2_can_store_new_dirty_bitmap(BlockDriverState *bs,
 722                                       const char *name,
 723                                       uint32_t granularity,
 724                                       Error **errp);
 725 void qcow2_remove_persistent_dirty_bitmap(BlockDriverState *bs,
 726                                           const char *name,
 727                                           Error **errp);
 728
 729 #endif