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![Kevin Wolf](/assets/img/avatar_default.png)
The offset within the cluster is already present as n_start and this is what the code uses. QCowL2Meta.offset is only needed at a cluster granularity. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
359 lines
11 KiB
C
359 lines
11 KiB
C
/*
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* Block driver for the QCOW version 2 format
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*
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* Copyright (c) 2004-2006 Fabrice Bellard
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#ifndef BLOCK_QCOW2_H
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#define BLOCK_QCOW2_H
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#include "aes.h"
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#include "qemu-coroutine.h"
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//#define DEBUG_ALLOC
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//#define DEBUG_ALLOC2
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//#define DEBUG_EXT
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#define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
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#define QCOW_CRYPT_NONE 0
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#define QCOW_CRYPT_AES 1
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#define QCOW_MAX_CRYPT_CLUSTERS 32
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/* indicate that the refcount of the referenced cluster is exactly one. */
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#define QCOW_OFLAG_COPIED (1LL << 63)
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/* indicate that the cluster is compressed (they never have the copied flag) */
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#define QCOW_OFLAG_COMPRESSED (1LL << 62)
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/* The cluster reads as all zeros */
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#define QCOW_OFLAG_ZERO (1LL << 0)
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#define REFCOUNT_SHIFT 1 /* refcount size is 2 bytes */
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#define MIN_CLUSTER_BITS 9
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#define MAX_CLUSTER_BITS 21
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#define L2_CACHE_SIZE 16
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/* Must be at least 4 to cover all cases of refcount table growth */
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#define REFCOUNT_CACHE_SIZE 4
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#define DEFAULT_CLUSTER_SIZE 65536
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typedef struct QCowHeader {
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uint32_t magic;
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uint32_t version;
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uint64_t backing_file_offset;
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uint32_t backing_file_size;
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uint32_t cluster_bits;
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uint64_t size; /* in bytes */
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uint32_t crypt_method;
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uint32_t l1_size; /* XXX: save number of clusters instead ? */
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uint64_t l1_table_offset;
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uint64_t refcount_table_offset;
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uint32_t refcount_table_clusters;
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uint32_t nb_snapshots;
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uint64_t snapshots_offset;
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/* The following fields are only valid for version >= 3 */
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uint64_t incompatible_features;
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uint64_t compatible_features;
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uint64_t autoclear_features;
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uint32_t refcount_order;
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uint32_t header_length;
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} QCowHeader;
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typedef struct QCowSnapshot {
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uint64_t l1_table_offset;
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uint32_t l1_size;
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char *id_str;
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char *name;
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uint64_t disk_size;
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uint64_t vm_state_size;
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uint32_t date_sec;
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uint32_t date_nsec;
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uint64_t vm_clock_nsec;
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} QCowSnapshot;
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struct Qcow2Cache;
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typedef struct Qcow2Cache Qcow2Cache;
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typedef struct Qcow2UnknownHeaderExtension {
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uint32_t magic;
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uint32_t len;
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QLIST_ENTRY(Qcow2UnknownHeaderExtension) next;
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uint8_t data[];
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} Qcow2UnknownHeaderExtension;
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enum {
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QCOW2_FEAT_TYPE_INCOMPATIBLE = 0,
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QCOW2_FEAT_TYPE_COMPATIBLE = 1,
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QCOW2_FEAT_TYPE_AUTOCLEAR = 2,
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};
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/* Incompatible feature bits */
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enum {
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QCOW2_INCOMPAT_DIRTY_BITNR = 0,
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QCOW2_INCOMPAT_DIRTY = 1 << QCOW2_INCOMPAT_DIRTY_BITNR,
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QCOW2_INCOMPAT_MASK = QCOW2_INCOMPAT_DIRTY,
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};
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/* Compatible feature bits */
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enum {
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QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR = 0,
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QCOW2_COMPAT_LAZY_REFCOUNTS = 1 << QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR,
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QCOW2_COMPAT_FEAT_MASK = QCOW2_COMPAT_LAZY_REFCOUNTS,
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};
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typedef struct Qcow2Feature {
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uint8_t type;
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uint8_t bit;
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char name[46];
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} QEMU_PACKED Qcow2Feature;
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typedef struct BDRVQcowState {
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int cluster_bits;
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int cluster_size;
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int cluster_sectors;
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int l2_bits;
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int l2_size;
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int l1_size;
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int l1_vm_state_index;
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int csize_shift;
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int csize_mask;
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uint64_t cluster_offset_mask;
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uint64_t l1_table_offset;
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uint64_t *l1_table;
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Qcow2Cache* l2_table_cache;
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Qcow2Cache* refcount_block_cache;
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uint8_t *cluster_cache;
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uint8_t *cluster_data;
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uint64_t cluster_cache_offset;
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QLIST_HEAD(QCowClusterAlloc, QCowL2Meta) cluster_allocs;
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uint64_t *refcount_table;
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uint64_t refcount_table_offset;
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uint32_t refcount_table_size;
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int64_t free_cluster_index;
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int64_t free_byte_offset;
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CoMutex lock;
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uint32_t crypt_method; /* current crypt method, 0 if no key yet */
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uint32_t crypt_method_header;
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AES_KEY aes_encrypt_key;
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AES_KEY aes_decrypt_key;
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uint64_t snapshots_offset;
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int snapshots_size;
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int nb_snapshots;
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QCowSnapshot *snapshots;
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int flags;
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int qcow_version;
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uint64_t incompatible_features;
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uint64_t compatible_features;
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uint64_t autoclear_features;
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size_t unknown_header_fields_size;
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void* unknown_header_fields;
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QLIST_HEAD(, Qcow2UnknownHeaderExtension) unknown_header_ext;
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} BDRVQcowState;
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/* XXX: use std qcow open function ? */
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typedef struct QCowCreateState {
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int cluster_size;
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int cluster_bits;
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uint16_t *refcount_block;
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uint64_t *refcount_table;
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int64_t l1_table_offset;
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int64_t refcount_table_offset;
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int64_t refcount_block_offset;
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} QCowCreateState;
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struct QCowAIOCB;
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/* XXX This could be private for qcow2-cluster.c */
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typedef struct QCowL2Meta
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{
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/** Guest offset of the first newly allocated cluster */
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uint64_t offset;
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/** Host offset of the first cluster of the request */
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uint64_t cluster_offset;
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/** Host offset of the first newly allocated cluster */
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uint64_t alloc_offset;
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/**
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* Number of sectors between the start of the first allocated cluster and
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* the area that the guest actually writes to.
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*/
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int n_start;
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/**
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* Number of sectors from the start of the first allocated cluster to
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* the end of the (possibly shortened) request
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*/
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int nb_available;
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/** Number of newly allocated clusters */
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int nb_clusters;
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/**
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* Requests that overlap with this allocation and wait to be restarted
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* when the allocating request has completed.
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*/
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CoQueue dependent_requests;
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QLIST_ENTRY(QCowL2Meta) next_in_flight;
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} QCowL2Meta;
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enum {
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QCOW2_CLUSTER_UNALLOCATED,
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QCOW2_CLUSTER_NORMAL,
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QCOW2_CLUSTER_COMPRESSED,
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QCOW2_CLUSTER_ZERO
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};
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#define L1E_OFFSET_MASK 0x00ffffffffffff00ULL
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#define L2E_OFFSET_MASK 0x00ffffffffffff00ULL
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#define L2E_COMPRESSED_OFFSET_SIZE_MASK 0x3fffffffffffffffULL
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#define REFT_OFFSET_MASK 0xffffffffffffff00ULL
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static inline int size_to_clusters(BDRVQcowState *s, int64_t size)
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{
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return (size + (s->cluster_size - 1)) >> s->cluster_bits;
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}
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static inline int size_to_l1(BDRVQcowState *s, int64_t size)
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{
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int shift = s->cluster_bits + s->l2_bits;
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return (size + (1ULL << shift) - 1) >> shift;
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}
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static inline int64_t align_offset(int64_t offset, int n)
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{
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offset = (offset + n - 1) & ~(n - 1);
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return offset;
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}
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static inline int qcow2_get_cluster_type(uint64_t l2_entry)
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{
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if (l2_entry & QCOW_OFLAG_COMPRESSED) {
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return QCOW2_CLUSTER_COMPRESSED;
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} else if (l2_entry & QCOW_OFLAG_ZERO) {
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return QCOW2_CLUSTER_ZERO;
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} else if (!(l2_entry & L2E_OFFSET_MASK)) {
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return QCOW2_CLUSTER_UNALLOCATED;
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} else {
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return QCOW2_CLUSTER_NORMAL;
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}
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}
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/* Check whether refcounts are eager or lazy */
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static inline bool qcow2_need_accurate_refcounts(BDRVQcowState *s)
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{
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return !(s->incompatible_features & QCOW2_INCOMPAT_DIRTY);
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}
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// FIXME Need qcow2_ prefix to global functions
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/* qcow2.c functions */
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int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov,
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int64_t sector_num, int nb_sectors);
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int qcow2_update_header(BlockDriverState *bs);
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/* qcow2-refcount.c functions */
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int qcow2_refcount_init(BlockDriverState *bs);
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void qcow2_refcount_close(BlockDriverState *bs);
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int64_t qcow2_alloc_clusters(BlockDriverState *bs, int64_t size);
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int qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset,
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int nb_clusters);
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int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size);
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void qcow2_free_clusters(BlockDriverState *bs,
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int64_t offset, int64_t size);
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void qcow2_free_any_clusters(BlockDriverState *bs,
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uint64_t cluster_offset, int nb_clusters);
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int qcow2_update_snapshot_refcount(BlockDriverState *bs,
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int64_t l1_table_offset, int l1_size, int addend);
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int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
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BdrvCheckMode fix);
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/* qcow2-cluster.c functions */
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int qcow2_grow_l1_table(BlockDriverState *bs, int min_size, bool exact_size);
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void qcow2_l2_cache_reset(BlockDriverState *bs);
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int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
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void qcow2_encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
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uint8_t *out_buf, const uint8_t *in_buf,
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int nb_sectors, int enc,
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const AES_KEY *key);
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int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,
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int *num, uint64_t *cluster_offset);
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int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,
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int n_start, int n_end, int *num, QCowL2Meta *m);
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uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
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uint64_t offset,
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int compressed_size);
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int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m);
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int qcow2_discard_clusters(BlockDriverState *bs, uint64_t offset,
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int nb_sectors);
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int qcow2_zero_clusters(BlockDriverState *bs, uint64_t offset, int nb_sectors);
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/* qcow2-snapshot.c functions */
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int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info);
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int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id);
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int qcow2_snapshot_delete(BlockDriverState *bs, const char *snapshot_id);
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int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab);
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int qcow2_snapshot_load_tmp(BlockDriverState *bs, const char *snapshot_name);
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void qcow2_free_snapshots(BlockDriverState *bs);
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int qcow2_read_snapshots(BlockDriverState *bs);
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/* qcow2-cache.c functions */
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Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables);
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int qcow2_cache_destroy(BlockDriverState* bs, Qcow2Cache *c);
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void qcow2_cache_entry_mark_dirty(Qcow2Cache *c, void *table);
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int qcow2_cache_flush(BlockDriverState *bs, Qcow2Cache *c);
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int qcow2_cache_set_dependency(BlockDriverState *bs, Qcow2Cache *c,
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Qcow2Cache *dependency);
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void qcow2_cache_depends_on_flush(Qcow2Cache *c);
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int qcow2_cache_get(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
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void **table);
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int qcow2_cache_get_empty(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
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void **table);
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int qcow2_cache_put(BlockDriverState *bs, Qcow2Cache *c, void **table);
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#endif
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