xref: /openbmc/qemu/block/qcow2.h (revision ae3c12a0)
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 /* Defined in the qcow2 spec (compressed cluster descriptor) */
78 #define QCOW2_COMPRESSED_SECTOR_SIZE 512U
79 #define QCOW2_COMPRESSED_SECTOR_MASK (~(QCOW2_COMPRESSED_SECTOR_SIZE - 1))
80 
81 /* Must be at least 2 to cover COW */
82 #define MIN_L2_CACHE_SIZE 2 /* cache entries */
83 
84 /* Must be at least 4 to cover all cases of refcount table growth */
85 #define MIN_REFCOUNT_CACHE_SIZE 4 /* clusters */
86 
87 #ifdef CONFIG_LINUX
88 #define DEFAULT_L2_CACHE_MAX_SIZE (32 * MiB)
89 #define DEFAULT_CACHE_CLEAN_INTERVAL 600  /* seconds */
90 #else
91 #define DEFAULT_L2_CACHE_MAX_SIZE (8 * MiB)
92 /* Cache clean interval is currently available only on Linux, so must be 0 */
93 #define DEFAULT_CACHE_CLEAN_INTERVAL 0
94 #endif
95 
96 #define DEFAULT_CLUSTER_SIZE 65536
97 
98 #define QCOW2_OPT_DATA_FILE "data-file"
99 #define QCOW2_OPT_LAZY_REFCOUNTS "lazy-refcounts"
100 #define QCOW2_OPT_DISCARD_REQUEST "pass-discard-request"
101 #define QCOW2_OPT_DISCARD_SNAPSHOT "pass-discard-snapshot"
102 #define QCOW2_OPT_DISCARD_OTHER "pass-discard-other"
103 #define QCOW2_OPT_OVERLAP "overlap-check"
104 #define QCOW2_OPT_OVERLAP_TEMPLATE "overlap-check.template"
105 #define QCOW2_OPT_OVERLAP_MAIN_HEADER "overlap-check.main-header"
106 #define QCOW2_OPT_OVERLAP_ACTIVE_L1 "overlap-check.active-l1"
107 #define QCOW2_OPT_OVERLAP_ACTIVE_L2 "overlap-check.active-l2"
108 #define QCOW2_OPT_OVERLAP_REFCOUNT_TABLE "overlap-check.refcount-table"
109 #define QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK "overlap-check.refcount-block"
110 #define QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE "overlap-check.snapshot-table"
111 #define QCOW2_OPT_OVERLAP_INACTIVE_L1 "overlap-check.inactive-l1"
112 #define QCOW2_OPT_OVERLAP_INACTIVE_L2 "overlap-check.inactive-l2"
113 #define QCOW2_OPT_OVERLAP_BITMAP_DIRECTORY "overlap-check.bitmap-directory"
114 #define QCOW2_OPT_CACHE_SIZE "cache-size"
115 #define QCOW2_OPT_L2_CACHE_SIZE "l2-cache-size"
116 #define QCOW2_OPT_L2_CACHE_ENTRY_SIZE "l2-cache-entry-size"
117 #define QCOW2_OPT_REFCOUNT_CACHE_SIZE "refcount-cache-size"
118 #define QCOW2_OPT_CACHE_CLEAN_INTERVAL "cache-clean-interval"
119 
120 typedef struct QCowHeader {
121     uint32_t magic;
122     uint32_t version;
123     uint64_t backing_file_offset;
124     uint32_t backing_file_size;
125     uint32_t cluster_bits;
126     uint64_t size; /* in bytes */
127     uint32_t crypt_method;
128     uint32_t l1_size; /* XXX: save number of clusters instead ? */
129     uint64_t l1_table_offset;
130     uint64_t refcount_table_offset;
131     uint32_t refcount_table_clusters;
132     uint32_t nb_snapshots;
133     uint64_t snapshots_offset;
134 
135     /* The following fields are only valid for version >= 3 */
136     uint64_t incompatible_features;
137     uint64_t compatible_features;
138     uint64_t autoclear_features;
139 
140     uint32_t refcount_order;
141     uint32_t header_length;
142 } QEMU_PACKED QCowHeader;
143 
144 typedef struct QEMU_PACKED QCowSnapshotHeader {
145     /* header is 8 byte aligned */
146     uint64_t l1_table_offset;
147 
148     uint32_t l1_size;
149     uint16_t id_str_size;
150     uint16_t name_size;
151 
152     uint32_t date_sec;
153     uint32_t date_nsec;
154 
155     uint64_t vm_clock_nsec;
156 
157     uint32_t vm_state_size;
158     uint32_t extra_data_size; /* for extension */
159     /* extra data follows */
160     /* id_str follows */
161     /* name follows  */
162 } QCowSnapshotHeader;
163 
164 typedef struct QEMU_PACKED QCowSnapshotExtraData {
165     uint64_t vm_state_size_large;
166     uint64_t disk_size;
167 } QCowSnapshotExtraData;
168 
169 
170 typedef struct QCowSnapshot {
171     uint64_t l1_table_offset;
172     uint32_t l1_size;
173     char *id_str;
174     char *name;
175     uint64_t disk_size;
176     uint64_t vm_state_size;
177     uint32_t date_sec;
178     uint32_t date_nsec;
179     uint64_t vm_clock_nsec;
180 } QCowSnapshot;
181 
182 struct Qcow2Cache;
183 typedef struct Qcow2Cache Qcow2Cache;
184 
185 typedef struct Qcow2CryptoHeaderExtension {
186     uint64_t offset;
187     uint64_t length;
188 } QEMU_PACKED Qcow2CryptoHeaderExtension;
189 
190 typedef struct Qcow2UnknownHeaderExtension {
191     uint32_t magic;
192     uint32_t len;
193     QLIST_ENTRY(Qcow2UnknownHeaderExtension) next;
194     uint8_t data[];
195 } Qcow2UnknownHeaderExtension;
196 
197 enum {
198     QCOW2_FEAT_TYPE_INCOMPATIBLE    = 0,
199     QCOW2_FEAT_TYPE_COMPATIBLE      = 1,
200     QCOW2_FEAT_TYPE_AUTOCLEAR       = 2,
201 };
202 
203 /* Incompatible feature bits */
204 enum {
205     QCOW2_INCOMPAT_DIRTY_BITNR      = 0,
206     QCOW2_INCOMPAT_CORRUPT_BITNR    = 1,
207     QCOW2_INCOMPAT_DATA_FILE_BITNR  = 2,
208     QCOW2_INCOMPAT_DIRTY            = 1 << QCOW2_INCOMPAT_DIRTY_BITNR,
209     QCOW2_INCOMPAT_CORRUPT          = 1 << QCOW2_INCOMPAT_CORRUPT_BITNR,
210     QCOW2_INCOMPAT_DATA_FILE        = 1 << QCOW2_INCOMPAT_DATA_FILE_BITNR,
211 
212     QCOW2_INCOMPAT_MASK             = QCOW2_INCOMPAT_DIRTY
213                                     | QCOW2_INCOMPAT_CORRUPT
214                                     | QCOW2_INCOMPAT_DATA_FILE,
215 };
216 
217 /* Compatible feature bits */
218 enum {
219     QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR = 0,
220     QCOW2_COMPAT_LAZY_REFCOUNTS       = 1 << QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR,
221 
222     QCOW2_COMPAT_FEAT_MASK            = QCOW2_COMPAT_LAZY_REFCOUNTS,
223 };
224 
225 /* Autoclear feature bits */
226 enum {
227     QCOW2_AUTOCLEAR_BITMAPS_BITNR       = 0,
228     QCOW2_AUTOCLEAR_DATA_FILE_RAW_BITNR = 1,
229     QCOW2_AUTOCLEAR_BITMAPS             = 1 << QCOW2_AUTOCLEAR_BITMAPS_BITNR,
230     QCOW2_AUTOCLEAR_DATA_FILE_RAW       = 1 << QCOW2_AUTOCLEAR_DATA_FILE_RAW_BITNR,
231 
232     QCOW2_AUTOCLEAR_MASK                = QCOW2_AUTOCLEAR_BITMAPS
233                                         | QCOW2_AUTOCLEAR_DATA_FILE_RAW,
234 };
235 
236 enum qcow2_discard_type {
237     QCOW2_DISCARD_NEVER = 0,
238     QCOW2_DISCARD_ALWAYS,
239     QCOW2_DISCARD_REQUEST,
240     QCOW2_DISCARD_SNAPSHOT,
241     QCOW2_DISCARD_OTHER,
242     QCOW2_DISCARD_MAX
243 };
244 
245 typedef struct Qcow2Feature {
246     uint8_t type;
247     uint8_t bit;
248     char    name[46];
249 } QEMU_PACKED Qcow2Feature;
250 
251 typedef struct Qcow2DiscardRegion {
252     BlockDriverState *bs;
253     uint64_t offset;
254     uint64_t bytes;
255     QTAILQ_ENTRY(Qcow2DiscardRegion) next;
256 } Qcow2DiscardRegion;
257 
258 typedef uint64_t Qcow2GetRefcountFunc(const void *refcount_array,
259                                       uint64_t index);
260 typedef void Qcow2SetRefcountFunc(void *refcount_array,
261                                   uint64_t index, uint64_t value);
262 
263 typedef struct Qcow2BitmapHeaderExt {
264     uint32_t nb_bitmaps;
265     uint32_t reserved32;
266     uint64_t bitmap_directory_size;
267     uint64_t bitmap_directory_offset;
268 } QEMU_PACKED Qcow2BitmapHeaderExt;
269 
270 typedef struct BDRVQcow2State {
271     int cluster_bits;
272     int cluster_size;
273     int l2_slice_size;
274     int l2_bits;
275     int l2_size;
276     int l1_size;
277     int l1_vm_state_index;
278     int refcount_block_bits;
279     int refcount_block_size;
280     int csize_shift;
281     int csize_mask;
282     uint64_t cluster_offset_mask;
283     uint64_t l1_table_offset;
284     uint64_t *l1_table;
285 
286     Qcow2Cache* l2_table_cache;
287     Qcow2Cache* refcount_block_cache;
288     QEMUTimer *cache_clean_timer;
289     unsigned cache_clean_interval;
290 
291     uint8_t *cluster_cache;
292     uint8_t *cluster_data;
293     uint64_t cluster_cache_offset;
294     QLIST_HEAD(, QCowL2Meta) cluster_allocs;
295 
296     uint64_t *refcount_table;
297     uint64_t refcount_table_offset;
298     uint32_t refcount_table_size;
299     uint32_t max_refcount_table_index; /* Last used entry in refcount_table */
300     uint64_t free_cluster_index;
301     uint64_t free_byte_offset;
302 
303     CoMutex lock;
304 
305     Qcow2CryptoHeaderExtension crypto_header; /* QCow2 header extension */
306     QCryptoBlockOpenOptions *crypto_opts; /* Disk encryption runtime options */
307     QCryptoBlock *crypto; /* Disk encryption format driver */
308     bool crypt_physical_offset; /* Whether to use virtual or physical offset
309                                    for encryption initialization vector tweak */
310     uint32_t crypt_method_header;
311     uint64_t snapshots_offset;
312     int snapshots_size;
313     unsigned int nb_snapshots;
314     QCowSnapshot *snapshots;
315 
316     uint32_t nb_bitmaps;
317     uint64_t bitmap_directory_size;
318     uint64_t bitmap_directory_offset;
319 
320     int flags;
321     int qcow_version;
322     bool use_lazy_refcounts;
323     int refcount_order;
324     int refcount_bits;
325     uint64_t refcount_max;
326 
327     Qcow2GetRefcountFunc *get_refcount;
328     Qcow2SetRefcountFunc *set_refcount;
329 
330     bool discard_passthrough[QCOW2_DISCARD_MAX];
331 
332     int overlap_check; /* bitmask of Qcow2MetadataOverlap values */
333     bool signaled_corruption;
334 
335     uint64_t incompatible_features;
336     uint64_t compatible_features;
337     uint64_t autoclear_features;
338 
339     size_t unknown_header_fields_size;
340     void* unknown_header_fields;
341     QLIST_HEAD(, Qcow2UnknownHeaderExtension) unknown_header_ext;
342     QTAILQ_HEAD (, Qcow2DiscardRegion) discards;
343     bool cache_discards;
344 
345     /* Backing file path and format as stored in the image (this is not the
346      * effective path/format, which may be the result of a runtime option
347      * override) */
348     char *image_backing_file;
349     char *image_backing_format;
350     char *image_data_file;
351 
352     CoQueue compress_wait_queue;
353     int nb_compress_threads;
354 
355     BdrvChild *data_file;
356 } BDRVQcow2State;
357 
358 typedef struct Qcow2COWRegion {
359     /**
360      * Offset of the COW region in bytes from the start of the first cluster
361      * touched by the request.
362      */
363     unsigned    offset;
364 
365     /** Number of bytes to copy */
366     unsigned    nb_bytes;
367 } Qcow2COWRegion;
368 
369 /**
370  * Describes an in-flight (part of a) write request that writes to clusters
371  * that are not referenced in their L2 table yet.
372  */
373 typedef struct QCowL2Meta
374 {
375     /** Guest offset of the first newly allocated cluster */
376     uint64_t offset;
377 
378     /** Host offset of the first newly allocated cluster */
379     uint64_t alloc_offset;
380 
381     /** Number of newly allocated clusters */
382     int nb_clusters;
383 
384     /** Do not free the old clusters */
385     bool keep_old_clusters;
386 
387     /**
388      * Requests that overlap with this allocation and wait to be restarted
389      * when the allocating request has completed.
390      */
391     CoQueue dependent_requests;
392 
393     /**
394      * The COW Region between the start of the first allocated cluster and the
395      * area the guest actually writes to.
396      */
397     Qcow2COWRegion cow_start;
398 
399     /**
400      * The COW Region between the area the guest actually writes to and the
401      * end of the last allocated cluster.
402      */
403     Qcow2COWRegion cow_end;
404 
405     /**
406      * The I/O vector with the data from the actual guest write request.
407      * If non-NULL, this is meant to be merged together with the data
408      * from @cow_start and @cow_end into one single write operation.
409      */
410     QEMUIOVector *data_qiov;
411 
412     /** Pointer to next L2Meta of the same write request */
413     struct QCowL2Meta *next;
414 
415     QLIST_ENTRY(QCowL2Meta) next_in_flight;
416 } QCowL2Meta;
417 
418 typedef enum QCow2ClusterType {
419     QCOW2_CLUSTER_UNALLOCATED,
420     QCOW2_CLUSTER_ZERO_PLAIN,
421     QCOW2_CLUSTER_ZERO_ALLOC,
422     QCOW2_CLUSTER_NORMAL,
423     QCOW2_CLUSTER_COMPRESSED,
424 } QCow2ClusterType;
425 
426 typedef enum QCow2MetadataOverlap {
427     QCOW2_OL_MAIN_HEADER_BITNR      = 0,
428     QCOW2_OL_ACTIVE_L1_BITNR        = 1,
429     QCOW2_OL_ACTIVE_L2_BITNR        = 2,
430     QCOW2_OL_REFCOUNT_TABLE_BITNR   = 3,
431     QCOW2_OL_REFCOUNT_BLOCK_BITNR   = 4,
432     QCOW2_OL_SNAPSHOT_TABLE_BITNR   = 5,
433     QCOW2_OL_INACTIVE_L1_BITNR      = 6,
434     QCOW2_OL_INACTIVE_L2_BITNR      = 7,
435     QCOW2_OL_BITMAP_DIRECTORY_BITNR = 8,
436 
437     QCOW2_OL_MAX_BITNR              = 9,
438 
439     QCOW2_OL_NONE             = 0,
440     QCOW2_OL_MAIN_HEADER      = (1 << QCOW2_OL_MAIN_HEADER_BITNR),
441     QCOW2_OL_ACTIVE_L1        = (1 << QCOW2_OL_ACTIVE_L1_BITNR),
442     QCOW2_OL_ACTIVE_L2        = (1 << QCOW2_OL_ACTIVE_L2_BITNR),
443     QCOW2_OL_REFCOUNT_TABLE   = (1 << QCOW2_OL_REFCOUNT_TABLE_BITNR),
444     QCOW2_OL_REFCOUNT_BLOCK   = (1 << QCOW2_OL_REFCOUNT_BLOCK_BITNR),
445     QCOW2_OL_SNAPSHOT_TABLE   = (1 << QCOW2_OL_SNAPSHOT_TABLE_BITNR),
446     QCOW2_OL_INACTIVE_L1      = (1 << QCOW2_OL_INACTIVE_L1_BITNR),
447     /* NOTE: Checking overlaps with inactive L2 tables will result in bdrv
448      * reads. */
449     QCOW2_OL_INACTIVE_L2      = (1 << QCOW2_OL_INACTIVE_L2_BITNR),
450     QCOW2_OL_BITMAP_DIRECTORY = (1 << QCOW2_OL_BITMAP_DIRECTORY_BITNR),
451 } QCow2MetadataOverlap;
452 
453 /* Perform all overlap checks which can be done in constant time */
454 #define QCOW2_OL_CONSTANT \
455     (QCOW2_OL_MAIN_HEADER | QCOW2_OL_ACTIVE_L1 | QCOW2_OL_REFCOUNT_TABLE | \
456      QCOW2_OL_SNAPSHOT_TABLE | QCOW2_OL_BITMAP_DIRECTORY)
457 
458 /* Perform all overlap checks which don't require disk access */
459 #define QCOW2_OL_CACHED \
460     (QCOW2_OL_CONSTANT | QCOW2_OL_ACTIVE_L2 | QCOW2_OL_REFCOUNT_BLOCK | \
461      QCOW2_OL_INACTIVE_L1)
462 
463 /* Perform all overlap checks */
464 #define QCOW2_OL_ALL \
465     (QCOW2_OL_CACHED | QCOW2_OL_INACTIVE_L2)
466 
467 #define L1E_OFFSET_MASK 0x00fffffffffffe00ULL
468 #define L2E_OFFSET_MASK 0x00fffffffffffe00ULL
469 #define L2E_COMPRESSED_OFFSET_SIZE_MASK 0x3fffffffffffffffULL
470 
471 #define REFT_OFFSET_MASK 0xfffffffffffffe00ULL
472 
473 #define INV_OFFSET (-1ULL)
474 
475 static inline bool has_data_file(BlockDriverState *bs)
476 {
477     BDRVQcow2State *s = bs->opaque;
478     return (s->data_file != bs->file);
479 }
480 
481 static inline bool data_file_is_raw(BlockDriverState *bs)
482 {
483     BDRVQcow2State *s = bs->opaque;
484     return !!(s->autoclear_features & QCOW2_AUTOCLEAR_DATA_FILE_RAW);
485 }
486 
487 static inline int64_t start_of_cluster(BDRVQcow2State *s, int64_t offset)
488 {
489     return offset & ~(s->cluster_size - 1);
490 }
491 
492 static inline int64_t offset_into_cluster(BDRVQcow2State *s, int64_t offset)
493 {
494     return offset & (s->cluster_size - 1);
495 }
496 
497 static inline uint64_t size_to_clusters(BDRVQcow2State *s, uint64_t size)
498 {
499     return (size + (s->cluster_size - 1)) >> s->cluster_bits;
500 }
501 
502 static inline int64_t size_to_l1(BDRVQcow2State *s, int64_t size)
503 {
504     int shift = s->cluster_bits + s->l2_bits;
505     return (size + (1ULL << shift) - 1) >> shift;
506 }
507 
508 static inline int offset_to_l1_index(BDRVQcow2State *s, uint64_t offset)
509 {
510     return offset >> (s->l2_bits + s->cluster_bits);
511 }
512 
513 static inline int offset_to_l2_index(BDRVQcow2State *s, int64_t offset)
514 {
515     return (offset >> s->cluster_bits) & (s->l2_size - 1);
516 }
517 
518 static inline int offset_to_l2_slice_index(BDRVQcow2State *s, int64_t offset)
519 {
520     return (offset >> s->cluster_bits) & (s->l2_slice_size - 1);
521 }
522 
523 static inline int64_t qcow2_vm_state_offset(BDRVQcow2State *s)
524 {
525     return (int64_t)s->l1_vm_state_index << (s->cluster_bits + s->l2_bits);
526 }
527 
528 static inline QCow2ClusterType qcow2_get_cluster_type(BlockDriverState *bs,
529                                                       uint64_t l2_entry)
530 {
531     if (l2_entry & QCOW_OFLAG_COMPRESSED) {
532         return QCOW2_CLUSTER_COMPRESSED;
533     } else if (l2_entry & QCOW_OFLAG_ZERO) {
534         if (l2_entry & L2E_OFFSET_MASK) {
535             return QCOW2_CLUSTER_ZERO_ALLOC;
536         }
537         return QCOW2_CLUSTER_ZERO_PLAIN;
538     } else if (!(l2_entry & L2E_OFFSET_MASK)) {
539         /* Offset 0 generally means unallocated, but it is ambiguous with
540          * external data files because 0 is a valid offset there. However, all
541          * clusters in external data files always have refcount 1, so we can
542          * rely on QCOW_OFLAG_COPIED to disambiguate. */
543         if (has_data_file(bs) && (l2_entry & QCOW_OFLAG_COPIED)) {
544             return QCOW2_CLUSTER_NORMAL;
545         } else {
546             return QCOW2_CLUSTER_UNALLOCATED;
547         }
548     } else {
549         return QCOW2_CLUSTER_NORMAL;
550     }
551 }
552 
553 /* Check whether refcounts are eager or lazy */
554 static inline bool qcow2_need_accurate_refcounts(BDRVQcow2State *s)
555 {
556     return !(s->incompatible_features & QCOW2_INCOMPAT_DIRTY);
557 }
558 
559 static inline uint64_t l2meta_cow_start(QCowL2Meta *m)
560 {
561     return m->offset + m->cow_start.offset;
562 }
563 
564 static inline uint64_t l2meta_cow_end(QCowL2Meta *m)
565 {
566     return m->offset + m->cow_end.offset + m->cow_end.nb_bytes;
567 }
568 
569 static inline uint64_t refcount_diff(uint64_t r1, uint64_t r2)
570 {
571     return r1 > r2 ? r1 - r2 : r2 - r1;
572 }
573 
574 static inline
575 uint32_t offset_to_reftable_index(BDRVQcow2State *s, uint64_t offset)
576 {
577     return offset >> (s->refcount_block_bits + s->cluster_bits);
578 }
579 
580 /* qcow2.c functions */
581 int64_t qcow2_refcount_metadata_size(int64_t clusters, size_t cluster_size,
582                                      int refcount_order, bool generous_increase,
583                                      uint64_t *refblock_count);
584 
585 int qcow2_mark_dirty(BlockDriverState *bs);
586 int qcow2_mark_corrupt(BlockDriverState *bs);
587 int qcow2_mark_consistent(BlockDriverState *bs);
588 int qcow2_update_header(BlockDriverState *bs);
589 
590 void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset,
591                              int64_t size, const char *message_format, ...)
592                              GCC_FMT_ATTR(5, 6);
593 
594 int qcow2_validate_table(BlockDriverState *bs, uint64_t offset,
595                          uint64_t entries, size_t entry_len,
596                          int64_t max_size_bytes, const char *table_name,
597                          Error **errp);
598 
599 /* qcow2-refcount.c functions */
600 int qcow2_refcount_init(BlockDriverState *bs);
601 void qcow2_refcount_close(BlockDriverState *bs);
602 
603 int qcow2_get_refcount(BlockDriverState *bs, int64_t cluster_index,
604                        uint64_t *refcount);
605 
606 int qcow2_update_cluster_refcount(BlockDriverState *bs, int64_t cluster_index,
607                                   uint64_t addend, bool decrease,
608                                   enum qcow2_discard_type type);
609 
610 int64_t qcow2_refcount_area(BlockDriverState *bs, uint64_t offset,
611                             uint64_t additional_clusters, bool exact_size,
612                             int new_refblock_index,
613                             uint64_t new_refblock_offset);
614 
615 int64_t qcow2_alloc_clusters(BlockDriverState *bs, uint64_t size);
616 int64_t qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset,
617                                 int64_t nb_clusters);
618 int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size);
619 void qcow2_free_clusters(BlockDriverState *bs,
620                           int64_t offset, int64_t size,
621                           enum qcow2_discard_type type);
622 void qcow2_free_any_clusters(BlockDriverState *bs, uint64_t l2_entry,
623                              int nb_clusters, enum qcow2_discard_type type);
624 
625 int qcow2_update_snapshot_refcount(BlockDriverState *bs,
626     int64_t l1_table_offset, int l1_size, int addend);
627 
628 int coroutine_fn qcow2_flush_caches(BlockDriverState *bs);
629 int coroutine_fn qcow2_write_caches(BlockDriverState *bs);
630 int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
631                           BdrvCheckMode fix);
632 
633 void qcow2_process_discards(BlockDriverState *bs, int ret);
634 
635 int qcow2_check_metadata_overlap(BlockDriverState *bs, int ign, int64_t offset,
636                                  int64_t size);
637 int qcow2_pre_write_overlap_check(BlockDriverState *bs, int ign, int64_t offset,
638                                   int64_t size, bool data_file);
639 int qcow2_inc_refcounts_imrt(BlockDriverState *bs, BdrvCheckResult *res,
640                              void **refcount_table,
641                              int64_t *refcount_table_size,
642                              int64_t offset, int64_t size);
643 
644 int qcow2_change_refcount_order(BlockDriverState *bs, int refcount_order,
645                                 BlockDriverAmendStatusCB *status_cb,
646                                 void *cb_opaque, Error **errp);
647 int qcow2_shrink_reftable(BlockDriverState *bs);
648 int64_t qcow2_get_last_cluster(BlockDriverState *bs, int64_t size);
649 
650 /* qcow2-cluster.c functions */
651 int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size,
652                         bool exact_size);
653 int qcow2_shrink_l1_table(BlockDriverState *bs, uint64_t max_size);
654 int qcow2_write_l1_entry(BlockDriverState *bs, int l1_index);
655 int qcow2_encrypt_sectors(BDRVQcow2State *s, int64_t sector_num,
656                           uint8_t *buf, int nb_sectors, bool enc, Error **errp);
657 
658 int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,
659                              unsigned int *bytes, uint64_t *cluster_offset);
660 int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,
661                                unsigned int *bytes, uint64_t *host_offset,
662                                QCowL2Meta **m);
663 int qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
664                                           uint64_t offset,
665                                           int compressed_size,
666                                           uint64_t *host_offset);
667 
668 int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m);
669 void qcow2_alloc_cluster_abort(BlockDriverState *bs, QCowL2Meta *m);
670 int qcow2_cluster_discard(BlockDriverState *bs, uint64_t offset,
671                           uint64_t bytes, enum qcow2_discard_type type,
672                           bool full_discard);
673 int qcow2_cluster_zeroize(BlockDriverState *bs, uint64_t offset,
674                           uint64_t bytes, int flags);
675 
676 int qcow2_expand_zero_clusters(BlockDriverState *bs,
677                                BlockDriverAmendStatusCB *status_cb,
678                                void *cb_opaque);
679 
680 /* qcow2-snapshot.c functions */
681 int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info);
682 int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id);
683 int qcow2_snapshot_delete(BlockDriverState *bs,
684                           const char *snapshot_id,
685                           const char *name,
686                           Error **errp);
687 int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab);
688 int qcow2_snapshot_load_tmp(BlockDriverState *bs,
689                             const char *snapshot_id,
690                             const char *name,
691                             Error **errp);
692 
693 void qcow2_free_snapshots(BlockDriverState *bs);
694 int qcow2_read_snapshots(BlockDriverState *bs);
695 
696 /* qcow2-cache.c functions */
697 Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables,
698                                unsigned table_size);
699 int qcow2_cache_destroy(Qcow2Cache *c);
700 
701 void qcow2_cache_entry_mark_dirty(Qcow2Cache *c, void *table);
702 int qcow2_cache_flush(BlockDriverState *bs, Qcow2Cache *c);
703 int qcow2_cache_write(BlockDriverState *bs, Qcow2Cache *c);
704 int qcow2_cache_set_dependency(BlockDriverState *bs, Qcow2Cache *c,
705     Qcow2Cache *dependency);
706 void qcow2_cache_depends_on_flush(Qcow2Cache *c);
707 
708 void qcow2_cache_clean_unused(Qcow2Cache *c);
709 int qcow2_cache_empty(BlockDriverState *bs, Qcow2Cache *c);
710 
711 int qcow2_cache_get(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
712     void **table);
713 int qcow2_cache_get_empty(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
714     void **table);
715 void qcow2_cache_put(Qcow2Cache *c, void **table);
716 void *qcow2_cache_is_table_offset(Qcow2Cache *c, uint64_t offset);
717 void qcow2_cache_discard(Qcow2Cache *c, void *table);
718 
719 /* qcow2-bitmap.c functions */
720 int qcow2_check_bitmaps_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
721                                   void **refcount_table,
722                                   int64_t *refcount_table_size);
723 bool qcow2_load_dirty_bitmaps(BlockDriverState *bs, Error **errp);
724 Qcow2BitmapInfoList *qcow2_get_bitmap_info_list(BlockDriverState *bs,
725                                                 Error **errp);
726 int qcow2_reopen_bitmaps_rw_hint(BlockDriverState *bs, bool *header_updated,
727                                  Error **errp);
728 int qcow2_reopen_bitmaps_rw(BlockDriverState *bs, Error **errp);
729 int qcow2_truncate_bitmaps_check(BlockDriverState *bs, Error **errp);
730 void qcow2_store_persistent_dirty_bitmaps(BlockDriverState *bs, Error **errp);
731 int qcow2_reopen_bitmaps_ro(BlockDriverState *bs, Error **errp);
732 bool qcow2_can_store_new_dirty_bitmap(BlockDriverState *bs,
733                                       const char *name,
734                                       uint32_t granularity,
735                                       Error **errp);
736 void qcow2_remove_persistent_dirty_bitmap(BlockDriverState *bs,
737                                           const char *name,
738                                           Error **errp);
739 
740 #endif
741