Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 1017 insertions, 0 deletions

diff --git a/block/qcow2.h b/block/qcow2.h
new file mode 100644
index 000000000..fd48a89d4
--- /dev/null
+++ b/block/qcow2.h
@@ -0,0 +1,1017 @@
+/*
+ * Block driver for the QCOW version 2 format
+ *
+ * Copyright (c) 2004-2006 Fabrice Bellard
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef BLOCK_QCOW2_H
+#define BLOCK_QCOW2_H
+
+#include "crypto/block.h"
+#include "qemu/coroutine.h"
+#include "qemu/units.h"
+#include "block/block_int.h"
+
+//#define DEBUG_ALLOC
+//#define DEBUG_ALLOC2
+//#define DEBUG_EXT
+
+#define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
+
+#define QCOW_CRYPT_NONE 0
+#define QCOW_CRYPT_AES  1
+#define QCOW_CRYPT_LUKS 2
+
+#define QCOW_MAX_CRYPT_CLUSTERS 32
+#define QCOW_MAX_SNAPSHOTS 65536
+
+/* Field widths in qcow2 mean normal cluster offsets cannot reach
+ * 64PB; depending on cluster size, compressed clusters can have a
+ * smaller limit (64PB for up to 16k clusters, then ramps down to
+ * 512TB for 2M clusters).  */
+#define QCOW_MAX_CLUSTER_OFFSET ((1ULL << 56) - 1)
+
+/* 8 MB refcount table is enough for 2 PB images at 64k cluster size
+ * (128 GB for 512 byte clusters, 2 EB for 2 MB clusters) */
+#define QCOW_MAX_REFTABLE_SIZE (8 * MiB)
+
+/* 32 MB L1 table is enough for 2 PB images at 64k cluster size
+ * (128 GB for 512 byte clusters, 2 EB for 2 MB clusters) */
+#define QCOW_MAX_L1_SIZE (32 * MiB)
+
+/* Allow for an average of 1k per snapshot table entry, should be plenty of
+ * space for snapshot names and IDs */
+#define QCOW_MAX_SNAPSHOTS_SIZE (1024 * QCOW_MAX_SNAPSHOTS)
+
+/* Maximum amount of extra data per snapshot table entry to accept */
+#define QCOW_MAX_SNAPSHOT_EXTRA_DATA 1024
+
+/* Bitmap header extension constraints */
+#define QCOW2_MAX_BITMAPS 65535
+#define QCOW2_MAX_BITMAP_DIRECTORY_SIZE (1024 * QCOW2_MAX_BITMAPS)
+
+/* Maximum of parallel sub-request per guest request */
+#define QCOW2_MAX_WORKERS 8
+
+/* indicate that the refcount of the referenced cluster is exactly one. */
+#define QCOW_OFLAG_COPIED     (1ULL << 63)
+/* indicate that the cluster is compressed (they never have the copied flag) */
+#define QCOW_OFLAG_COMPRESSED (1ULL << 62)
+/* The cluster reads as all zeros */
+#define QCOW_OFLAG_ZERO (1ULL << 0)
+
+#define QCOW_EXTL2_SUBCLUSTERS_PER_CLUSTER 32
+
+/* The subcluster X [0..31] is allocated */
+#define QCOW_OFLAG_SUB_ALLOC(X)   (1ULL << (X))
+/* The subcluster X [0..31] reads as zeroes */
+#define QCOW_OFLAG_SUB_ZERO(X)    (QCOW_OFLAG_SUB_ALLOC(X) << 32)
+/* Subclusters [X, Y) (0 <= X <= Y <= 32) are allocated */
+#define QCOW_OFLAG_SUB_ALLOC_RANGE(X, Y) \
+    (QCOW_OFLAG_SUB_ALLOC(Y) - QCOW_OFLAG_SUB_ALLOC(X))
+/* Subclusters [X, Y) (0 <= X <= Y <= 32) read as zeroes */
+#define QCOW_OFLAG_SUB_ZERO_RANGE(X, Y) \
+    (QCOW_OFLAG_SUB_ALLOC_RANGE(X, Y) << 32)
+/* L2 entry bitmap with all allocation bits set */
+#define QCOW_L2_BITMAP_ALL_ALLOC  (QCOW_OFLAG_SUB_ALLOC_RANGE(0, 32))
+/* L2 entry bitmap with all "read as zeroes" bits set */
+#define QCOW_L2_BITMAP_ALL_ZEROES (QCOW_OFLAG_SUB_ZERO_RANGE(0, 32))
+
+/* Size of normal and extended L2 entries */
+#define L2E_SIZE_NORMAL   (sizeof(uint64_t))
+#define L2E_SIZE_EXTENDED (sizeof(uint64_t) * 2)
+
+/* Size of L1 table entries */
+#define L1E_SIZE (sizeof(uint64_t))
+
+/* Size of reftable entries */
+#define REFTABLE_ENTRY_SIZE (sizeof(uint64_t))
+
+#define MIN_CLUSTER_BITS 9
+#define MAX_CLUSTER_BITS 21
+
+/* Defined in the qcow2 spec (compressed cluster descriptor) */
+#define QCOW2_COMPRESSED_SECTOR_SIZE 512U
+
+/* Must be at least 2 to cover COW */
+#define MIN_L2_CACHE_SIZE 2 /* cache entries */
+
+/* Must be at least 4 to cover all cases of refcount table growth */
+#define MIN_REFCOUNT_CACHE_SIZE 4 /* clusters */
+
+#ifdef CONFIG_LINUX
+#define DEFAULT_L2_CACHE_MAX_SIZE (32 * MiB)
+#define DEFAULT_CACHE_CLEAN_INTERVAL 600  /* seconds */
+#else
+#define DEFAULT_L2_CACHE_MAX_SIZE (8 * MiB)
+/* Cache clean interval is currently available only on Linux, so must be 0 */
+#define DEFAULT_CACHE_CLEAN_INTERVAL 0
+#endif
+
+#define DEFAULT_CLUSTER_SIZE 65536
+
+#define QCOW2_OPT_DATA_FILE "data-file"
+#define QCOW2_OPT_LAZY_REFCOUNTS "lazy-refcounts"
+#define QCOW2_OPT_DISCARD_REQUEST "pass-discard-request"
+#define QCOW2_OPT_DISCARD_SNAPSHOT "pass-discard-snapshot"
+#define QCOW2_OPT_DISCARD_OTHER "pass-discard-other"
+#define QCOW2_OPT_OVERLAP "overlap-check"
+#define QCOW2_OPT_OVERLAP_TEMPLATE "overlap-check.template"
+#define QCOW2_OPT_OVERLAP_MAIN_HEADER "overlap-check.main-header"
+#define QCOW2_OPT_OVERLAP_ACTIVE_L1 "overlap-check.active-l1"
+#define QCOW2_OPT_OVERLAP_ACTIVE_L2 "overlap-check.active-l2"
+#define QCOW2_OPT_OVERLAP_REFCOUNT_TABLE "overlap-check.refcount-table"
+#define QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK "overlap-check.refcount-block"
+#define QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE "overlap-check.snapshot-table"
+#define QCOW2_OPT_OVERLAP_INACTIVE_L1 "overlap-check.inactive-l1"
+#define QCOW2_OPT_OVERLAP_INACTIVE_L2 "overlap-check.inactive-l2"
+#define QCOW2_OPT_OVERLAP_BITMAP_DIRECTORY "overlap-check.bitmap-directory"
+#define QCOW2_OPT_CACHE_SIZE "cache-size"
+#define QCOW2_OPT_L2_CACHE_SIZE "l2-cache-size"
+#define QCOW2_OPT_L2_CACHE_ENTRY_SIZE "l2-cache-entry-size"
+#define QCOW2_OPT_REFCOUNT_CACHE_SIZE "refcount-cache-size"
+#define QCOW2_OPT_CACHE_CLEAN_INTERVAL "cache-clean-interval"
+
+typedef struct QCowHeader {
+    uint32_t magic;
+    uint32_t version;
+    uint64_t backing_file_offset;
+    uint32_t backing_file_size;
+    uint32_t cluster_bits;
+    uint64_t size; /* in bytes */
+    uint32_t crypt_method;
+    uint32_t l1_size; /* XXX: save number of clusters instead ? */
+    uint64_t l1_table_offset;
+    uint64_t refcount_table_offset;
+    uint32_t refcount_table_clusters;
+    uint32_t nb_snapshots;
+    uint64_t snapshots_offset;
+
+    /* The following fields are only valid for version >= 3 */
+    uint64_t incompatible_features;
+    uint64_t compatible_features;
+    uint64_t autoclear_features;
+
+    uint32_t refcount_order;
+    uint32_t header_length;
+
+    /* Additional fields */
+    uint8_t compression_type;
+
+    /* header must be a multiple of 8 */
+    uint8_t padding[7];
+} QEMU_PACKED QCowHeader;
+
+QEMU_BUILD_BUG_ON(!QEMU_IS_ALIGNED(sizeof(QCowHeader), 8));
+
+typedef struct QEMU_PACKED QCowSnapshotHeader {
+    /* header is 8 byte aligned */
+    uint64_t l1_table_offset;
+
+    uint32_t l1_size;
+    uint16_t id_str_size;
+    uint16_t name_size;
+
+    uint32_t date_sec;
+    uint32_t date_nsec;
+
+    uint64_t vm_clock_nsec;
+
+    uint32_t vm_state_size;
+    uint32_t extra_data_size; /* for extension */
+    /* extra data follows */
+    /* id_str follows */
+    /* name follows  */
+} QCowSnapshotHeader;
+
+typedef struct QEMU_PACKED QCowSnapshotExtraData {
+    uint64_t vm_state_size_large;
+    uint64_t disk_size;
+    uint64_t icount;
+} QCowSnapshotExtraData;
+
+
+typedef struct QCowSnapshot {
+    uint64_t l1_table_offset;
+    uint32_t l1_size;
+    char *id_str;
+    char *name;
+    uint64_t disk_size;
+    uint64_t vm_state_size;
+    uint32_t date_sec;
+    uint32_t date_nsec;
+    uint64_t vm_clock_nsec;
+    /* icount value for the moment when snapshot was taken */
+    uint64_t icount;
+    /* Size of all extra data, including QCowSnapshotExtraData if available */
+    uint32_t extra_data_size;
+    /* Data beyond QCowSnapshotExtraData, if any */
+    void *unknown_extra_data;
+} QCowSnapshot;
+
+struct Qcow2Cache;
+typedef struct Qcow2Cache Qcow2Cache;
+
+typedef struct Qcow2CryptoHeaderExtension {
+    uint64_t offset;
+    uint64_t length;
+} QEMU_PACKED Qcow2CryptoHeaderExtension;
+
+typedef struct Qcow2UnknownHeaderExtension {
+    uint32_t magic;
+    uint32_t len;
+    QLIST_ENTRY(Qcow2UnknownHeaderExtension) next;
+    uint8_t data[];
+} Qcow2UnknownHeaderExtension;
+
+enum {
+    QCOW2_FEAT_TYPE_INCOMPATIBLE    = 0,
+    QCOW2_FEAT_TYPE_COMPATIBLE      = 1,
+    QCOW2_FEAT_TYPE_AUTOCLEAR       = 2,
+};
+
+/* Incompatible feature bits */
+enum {
+    QCOW2_INCOMPAT_DIRTY_BITNR      = 0,
+    QCOW2_INCOMPAT_CORRUPT_BITNR    = 1,
+    QCOW2_INCOMPAT_DATA_FILE_BITNR  = 2,
+    QCOW2_INCOMPAT_COMPRESSION_BITNR = 3,
+    QCOW2_INCOMPAT_EXTL2_BITNR      = 4,
+    QCOW2_INCOMPAT_DIRTY            = 1 << QCOW2_INCOMPAT_DIRTY_BITNR,
+    QCOW2_INCOMPAT_CORRUPT          = 1 << QCOW2_INCOMPAT_CORRUPT_BITNR,
+    QCOW2_INCOMPAT_DATA_FILE        = 1 << QCOW2_INCOMPAT_DATA_FILE_BITNR,
+    QCOW2_INCOMPAT_COMPRESSION      = 1 << QCOW2_INCOMPAT_COMPRESSION_BITNR,
+    QCOW2_INCOMPAT_EXTL2            = 1 << QCOW2_INCOMPAT_EXTL2_BITNR,
+
+    QCOW2_INCOMPAT_MASK             = QCOW2_INCOMPAT_DIRTY
+                                    | QCOW2_INCOMPAT_CORRUPT
+                                    | QCOW2_INCOMPAT_DATA_FILE
+                                    | QCOW2_INCOMPAT_COMPRESSION
+                                    | QCOW2_INCOMPAT_EXTL2,
+};
+
+/* Compatible feature bits */
+enum {
+    QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR = 0,
+    QCOW2_COMPAT_LAZY_REFCOUNTS       = 1 << QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR,
+
+    QCOW2_COMPAT_FEAT_MASK            = QCOW2_COMPAT_LAZY_REFCOUNTS,
+};
+
+/* Autoclear feature bits */
+enum {
+    QCOW2_AUTOCLEAR_BITMAPS_BITNR       = 0,
+    QCOW2_AUTOCLEAR_DATA_FILE_RAW_BITNR = 1,
+    QCOW2_AUTOCLEAR_BITMAPS             = 1 << QCOW2_AUTOCLEAR_BITMAPS_BITNR,
+    QCOW2_AUTOCLEAR_DATA_FILE_RAW       = 1 << QCOW2_AUTOCLEAR_DATA_FILE_RAW_BITNR,
+
+    QCOW2_AUTOCLEAR_MASK                = QCOW2_AUTOCLEAR_BITMAPS
+                                        | QCOW2_AUTOCLEAR_DATA_FILE_RAW,
+};
+
+enum qcow2_discard_type {
+    QCOW2_DISCARD_NEVER = 0,
+    QCOW2_DISCARD_ALWAYS,
+    QCOW2_DISCARD_REQUEST,
+    QCOW2_DISCARD_SNAPSHOT,
+    QCOW2_DISCARD_OTHER,
+    QCOW2_DISCARD_MAX
+};
+
+typedef struct Qcow2Feature {
+    uint8_t type;
+    uint8_t bit;
+    char    name[46];
+} QEMU_PACKED Qcow2Feature;
+
+typedef struct Qcow2DiscardRegion {
+    BlockDriverState *bs;
+    uint64_t offset;
+    uint64_t bytes;
+    QTAILQ_ENTRY(Qcow2DiscardRegion) next;
+} Qcow2DiscardRegion;
+
+typedef uint64_t Qcow2GetRefcountFunc(const void *refcount_array,
+                                      uint64_t index);
+typedef void Qcow2SetRefcountFunc(void *refcount_array,
+                                  uint64_t index, uint64_t value);
+
+typedef struct Qcow2BitmapHeaderExt {
+    uint32_t nb_bitmaps;
+    uint32_t reserved32;
+    uint64_t bitmap_directory_size;
+    uint64_t bitmap_directory_offset;
+} QEMU_PACKED Qcow2BitmapHeaderExt;
+
+#define QCOW2_MAX_THREADS 4
+
+typedef struct BDRVQcow2State {
+    int cluster_bits;
+    int cluster_size;
+    int l2_slice_size;
+    int subcluster_bits;
+    int subcluster_size;
+    int subclusters_per_cluster;
+    int l2_bits;
+    int l2_size;
+    int l1_size;
+    int l1_vm_state_index;
+    int refcount_block_bits;
+    int refcount_block_size;
+    int csize_shift;
+    int csize_mask;
+    uint64_t cluster_offset_mask;
+    uint64_t l1_table_offset;
+    uint64_t *l1_table;
+
+    Qcow2Cache *l2_table_cache;
+    Qcow2Cache *refcount_block_cache;
+    QEMUTimer *cache_clean_timer;
+    unsigned cache_clean_interval;
+
+    QLIST_HEAD(, QCowL2Meta) cluster_allocs;
+
+    uint64_t *refcount_table;
+    uint64_t refcount_table_offset;
+    uint32_t refcount_table_size;
+    uint32_t max_refcount_table_index; /* Last used entry in refcount_table */
+    uint64_t free_cluster_index;
+    uint64_t free_byte_offset;
+
+    CoMutex lock;
+
+    Qcow2CryptoHeaderExtension crypto_header; /* QCow2 header extension */
+    QCryptoBlockOpenOptions *crypto_opts; /* Disk encryption runtime options */
+    QCryptoBlock *crypto; /* Disk encryption format driver */
+    bool crypt_physical_offset; /* Whether to use virtual or physical offset
+                                   for encryption initialization vector tweak */
+    uint32_t crypt_method_header;
+    uint64_t snapshots_offset;
+    int snapshots_size;
+    unsigned int nb_snapshots;
+    QCowSnapshot *snapshots;
+
+    uint32_t nb_bitmaps;
+    uint64_t bitmap_directory_size;
+    uint64_t bitmap_directory_offset;
+
+    int flags;
+    int qcow_version;
+    bool use_lazy_refcounts;
+    int refcount_order;
+    int refcount_bits;
+    uint64_t refcount_max;
+
+    Qcow2GetRefcountFunc *get_refcount;
+    Qcow2SetRefcountFunc *set_refcount;
+
+    bool discard_passthrough[QCOW2_DISCARD_MAX];
+
+    int overlap_check; /* bitmask of Qcow2MetadataOverlap values */
+    bool signaled_corruption;
+
+    uint64_t incompatible_features;
+    uint64_t compatible_features;
+    uint64_t autoclear_features;
+
+    size_t unknown_header_fields_size;
+    void *unknown_header_fields;
+    QLIST_HEAD(, Qcow2UnknownHeaderExtension) unknown_header_ext;
+    QTAILQ_HEAD (, Qcow2DiscardRegion) discards;
+    bool cache_discards;
+
+    /* Backing file path and format as stored in the image (this is not the
+     * effective path/format, which may be the result of a runtime option
+     * override) */
+    char *image_backing_file;
+    char *image_backing_format;
+    char *image_data_file;
+
+    CoQueue thread_task_queue;
+    int nb_threads;
+
+    BdrvChild *data_file;
+
+    bool metadata_preallocation_checked;
+    bool metadata_preallocation;
+    /*
+     * Compression type used for the image. Default: 0 - ZLIB
+     * The image compression type is set on image creation.
+     * For now, the only way to change the compression type
+     * is to convert the image with the desired compression type set.
+     */
+    Qcow2CompressionType compression_type;
+} BDRVQcow2State;
+
+typedef struct Qcow2COWRegion {
+    /**
+     * Offset of the COW region in bytes from the start of the first cluster
+     * touched by the request.
+     */
+    unsigned    offset;
+
+    /** Number of bytes to copy */
+    unsigned    nb_bytes;
+} Qcow2COWRegion;
+
+/**
+ * Describes an in-flight (part of a) write request that writes to clusters
+ * that need to have their L2 table entries updated (because they are
+ * newly allocated or need changes in their L2 bitmaps)
+ */
+typedef struct QCowL2Meta
+{
+    /** Guest offset of the first updated cluster */
+    uint64_t offset;
+
+    /** Host offset of the first updated cluster */
+    uint64_t alloc_offset;
+
+    /** Number of updated clusters */
+    int nb_clusters;
+
+    /** Do not free the old clusters */
+    bool keep_old_clusters;
+
+    /**
+     * Requests that overlap with this allocation and wait to be restarted
+     * when the allocating request has completed.
+     */
+    CoQueue dependent_requests;
+
+    /**
+     * The COW Region immediately before the area the guest actually
+     * writes to. This (part of the) write request starts at
+     * cow_start.offset + cow_start.nb_bytes.
+     */
+    Qcow2COWRegion cow_start;
+
+    /**
+     * The COW Region immediately after the area the guest actually
+     * writes to. This (part of the) write request ends at cow_end.offset
+     * (which must always be set even when cow_end.nb_bytes is 0).
+     */
+    Qcow2COWRegion cow_end;
+
+    /*
+     * Indicates that COW regions are already handled and do not require
+     * any more processing.
+     */
+    bool skip_cow;
+
+    /**
+     * Indicates that this is not a normal write request but a preallocation.
+     * If the image has extended L2 entries this means that no new individual
+     * subclusters will be marked as allocated in the L2 bitmap (but any
+     * existing contents of that bitmap will be kept).
+     */
+    bool prealloc;
+
+    /**
+     * The I/O vector with the data from the actual guest write request.
+     * If non-NULL, this is meant to be merged together with the data
+     * from @cow_start and @cow_end into one single write operation.
+     */
+    QEMUIOVector *data_qiov;
+    size_t data_qiov_offset;
+
+    /** Pointer to next L2Meta of the same write request */
+    struct QCowL2Meta *next;
+
+    QLIST_ENTRY(QCowL2Meta) next_in_flight;
+} QCowL2Meta;
+
+/*
+ * In images with standard L2 entries all clusters are treated as if
+ * they had one subcluster so QCow2ClusterType and QCow2SubclusterType
+ * can be mapped to each other and have the exact same meaning
+ * (QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC cannot happen in these images).
+ *
+ * In images with extended L2 entries QCow2ClusterType refers to the
+ * complete cluster and QCow2SubclusterType to each of the individual
+ * subclusters, so there are several possible combinations:
+ *
+ *     |--------------+---------------------------|
+ *     | Cluster type | Possible subcluster types |
+ *     |--------------+---------------------------|
+ *     | UNALLOCATED  |         UNALLOCATED_PLAIN |
+ *     |              |                ZERO_PLAIN |
+ *     |--------------+---------------------------|
+ *     | NORMAL       |         UNALLOCATED_ALLOC |
+ *     |              |                ZERO_ALLOC |
+ *     |              |                    NORMAL |
+ *     |--------------+---------------------------|
+ *     | COMPRESSED   |                COMPRESSED |
+ *     |--------------+---------------------------|
+ *
+ * QCOW2_SUBCLUSTER_INVALID means that the L2 entry is incorrect and
+ * the image should be marked corrupt.
+ */
+
+typedef enum QCow2ClusterType {
+    QCOW2_CLUSTER_UNALLOCATED,
+    QCOW2_CLUSTER_ZERO_PLAIN,
+    QCOW2_CLUSTER_ZERO_ALLOC,
+    QCOW2_CLUSTER_NORMAL,
+    QCOW2_CLUSTER_COMPRESSED,
+} QCow2ClusterType;
+
+typedef enum QCow2SubclusterType {
+    QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN,
+    QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC,
+    QCOW2_SUBCLUSTER_ZERO_PLAIN,
+    QCOW2_SUBCLUSTER_ZERO_ALLOC,
+    QCOW2_SUBCLUSTER_NORMAL,
+    QCOW2_SUBCLUSTER_COMPRESSED,
+    QCOW2_SUBCLUSTER_INVALID,
+} QCow2SubclusterType;
+
+typedef enum QCow2MetadataOverlap {
+    QCOW2_OL_MAIN_HEADER_BITNR      = 0,
+    QCOW2_OL_ACTIVE_L1_BITNR        = 1,
+    QCOW2_OL_ACTIVE_L2_BITNR        = 2,
+    QCOW2_OL_REFCOUNT_TABLE_BITNR   = 3,
+    QCOW2_OL_REFCOUNT_BLOCK_BITNR   = 4,
+    QCOW2_OL_SNAPSHOT_TABLE_BITNR   = 5,
+    QCOW2_OL_INACTIVE_L1_BITNR      = 6,
+    QCOW2_OL_INACTIVE_L2_BITNR      = 7,
+    QCOW2_OL_BITMAP_DIRECTORY_BITNR = 8,
+
+    QCOW2_OL_MAX_BITNR              = 9,
+
+    QCOW2_OL_NONE             = 0,
+    QCOW2_OL_MAIN_HEADER      = (1 << QCOW2_OL_MAIN_HEADER_BITNR),
+    QCOW2_OL_ACTIVE_L1        = (1 << QCOW2_OL_ACTIVE_L1_BITNR),
+    QCOW2_OL_ACTIVE_L2        = (1 << QCOW2_OL_ACTIVE_L2_BITNR),
+    QCOW2_OL_REFCOUNT_TABLE   = (1 << QCOW2_OL_REFCOUNT_TABLE_BITNR),
+    QCOW2_OL_REFCOUNT_BLOCK   = (1 << QCOW2_OL_REFCOUNT_BLOCK_BITNR),
+    QCOW2_OL_SNAPSHOT_TABLE   = (1 << QCOW2_OL_SNAPSHOT_TABLE_BITNR),
+    QCOW2_OL_INACTIVE_L1      = (1 << QCOW2_OL_INACTIVE_L1_BITNR),
+    /* NOTE: Checking overlaps with inactive L2 tables will result in bdrv
+     * reads. */
+    QCOW2_OL_INACTIVE_L2      = (1 << QCOW2_OL_INACTIVE_L2_BITNR),
+    QCOW2_OL_BITMAP_DIRECTORY = (1 << QCOW2_OL_BITMAP_DIRECTORY_BITNR),
+} QCow2MetadataOverlap;
+
+/* Perform all overlap checks which can be done in constant time */
+#define QCOW2_OL_CONSTANT \
+    (QCOW2_OL_MAIN_HEADER | QCOW2_OL_ACTIVE_L1 | QCOW2_OL_REFCOUNT_TABLE | \
+     QCOW2_OL_SNAPSHOT_TABLE | QCOW2_OL_BITMAP_DIRECTORY)
+
+/* Perform all overlap checks which don't require disk access */
+#define QCOW2_OL_CACHED \
+    (QCOW2_OL_CONSTANT | QCOW2_OL_ACTIVE_L2 | QCOW2_OL_REFCOUNT_BLOCK | \
+     QCOW2_OL_INACTIVE_L1)
+
+/* Perform all overlap checks */
+#define QCOW2_OL_ALL \
+    (QCOW2_OL_CACHED | QCOW2_OL_INACTIVE_L2)
+
+#define L1E_OFFSET_MASK 0x00fffffffffffe00ULL
+#define L1E_RESERVED_MASK 0x7f000000000001ffULL
+#define L2E_OFFSET_MASK 0x00fffffffffffe00ULL
+#define L2E_STD_RESERVED_MASK 0x3f000000000001feULL
+
+#define REFT_OFFSET_MASK 0xfffffffffffffe00ULL
+#define REFT_RESERVED_MASK 0x1ffULL
+
+#define INV_OFFSET (-1ULL)
+
+static inline bool has_subclusters(BDRVQcow2State *s)
+{
+    return s->incompatible_features & QCOW2_INCOMPAT_EXTL2;
+}
+
+static inline size_t l2_entry_size(BDRVQcow2State *s)
+{
+    return has_subclusters(s) ? L2E_SIZE_EXTENDED : L2E_SIZE_NORMAL;
+}
+
+static inline uint64_t get_l2_entry(BDRVQcow2State *s, uint64_t *l2_slice,
+                                    int idx)
+{
+    idx *= l2_entry_size(s) / sizeof(uint64_t);
+    return be64_to_cpu(l2_slice[idx]);
+}
+
+static inline uint64_t get_l2_bitmap(BDRVQcow2State *s, uint64_t *l2_slice,
+                                     int idx)
+{
+    if (has_subclusters(s)) {
+        idx *= l2_entry_size(s) / sizeof(uint64_t);
+        return be64_to_cpu(l2_slice[idx + 1]);
+    } else {
+        return 0; /* For convenience only; this value has no meaning. */
+    }
+}
+
+static inline void set_l2_entry(BDRVQcow2State *s, uint64_t *l2_slice,
+                                int idx, uint64_t entry)
+{
+    idx *= l2_entry_size(s) / sizeof(uint64_t);
+    l2_slice[idx] = cpu_to_be64(entry);
+}
+
+static inline void set_l2_bitmap(BDRVQcow2State *s, uint64_t *l2_slice,
+                                 int idx, uint64_t bitmap)
+{
+    assert(has_subclusters(s));
+    idx *= l2_entry_size(s) / sizeof(uint64_t);
+    l2_slice[idx + 1] = cpu_to_be64(bitmap);
+}
+
+static inline bool has_data_file(BlockDriverState *bs)
+{
+    BDRVQcow2State *s = bs->opaque;
+    return (s->data_file != bs->file);
+}
+
+static inline bool data_file_is_raw(BlockDriverState *bs)
+{
+    BDRVQcow2State *s = bs->opaque;
+    return !!(s->autoclear_features & QCOW2_AUTOCLEAR_DATA_FILE_RAW);
+}
+
+static inline int64_t start_of_cluster(BDRVQcow2State *s, int64_t offset)
+{
+    return offset & ~(s->cluster_size - 1);
+}
+
+static inline int64_t offset_into_cluster(BDRVQcow2State *s, int64_t offset)
+{
+    return offset & (s->cluster_size - 1);
+}
+
+static inline int64_t offset_into_subcluster(BDRVQcow2State *s, int64_t offset)
+{
+    return offset & (s->subcluster_size - 1);
+}
+
+static inline uint64_t size_to_clusters(BDRVQcow2State *s, uint64_t size)
+{
+    return (size + (s->cluster_size - 1)) >> s->cluster_bits;
+}
+
+static inline uint64_t size_to_subclusters(BDRVQcow2State *s, uint64_t size)
+{
+    return (size + (s->subcluster_size - 1)) >> s->subcluster_bits;
+}
+
+static inline int64_t size_to_l1(BDRVQcow2State *s, int64_t size)
+{
+    int shift = s->cluster_bits + s->l2_bits;
+    return (size + (1ULL << shift) - 1) >> shift;
+}
+
+static inline int offset_to_l1_index(BDRVQcow2State *s, uint64_t offset)
+{
+    return offset >> (s->l2_bits + s->cluster_bits);
+}
+
+static inline int offset_to_l2_index(BDRVQcow2State *s, int64_t offset)
+{
+    return (offset >> s->cluster_bits) & (s->l2_size - 1);
+}
+
+static inline int offset_to_l2_slice_index(BDRVQcow2State *s, int64_t offset)
+{
+    return (offset >> s->cluster_bits) & (s->l2_slice_size - 1);
+}
+
+static inline int offset_to_sc_index(BDRVQcow2State *s, int64_t offset)
+{
+    return (offset >> s->subcluster_bits) & (s->subclusters_per_cluster - 1);
+}
+
+static inline int64_t qcow2_vm_state_offset(BDRVQcow2State *s)
+{
+    return (int64_t)s->l1_vm_state_index << (s->cluster_bits + s->l2_bits);
+}
+
+static inline QCow2ClusterType qcow2_get_cluster_type(BlockDriverState *bs,
+                                                      uint64_t l2_entry)
+{
+    BDRVQcow2State *s = bs->opaque;
+
+    if (l2_entry & QCOW_OFLAG_COMPRESSED) {
+        return QCOW2_CLUSTER_COMPRESSED;
+    } else if ((l2_entry & QCOW_OFLAG_ZERO) && !has_subclusters(s)) {
+        if (l2_entry & L2E_OFFSET_MASK) {
+            return QCOW2_CLUSTER_ZERO_ALLOC;
+        }
+        return QCOW2_CLUSTER_ZERO_PLAIN;
+    } else if (!(l2_entry & L2E_OFFSET_MASK)) {
+        /* Offset 0 generally means unallocated, but it is ambiguous with
+         * external data files because 0 is a valid offset there. However, all
+         * clusters in external data files always have refcount 1, so we can
+         * rely on QCOW_OFLAG_COPIED to disambiguate. */
+        if (has_data_file(bs) && (l2_entry & QCOW_OFLAG_COPIED)) {
+            return QCOW2_CLUSTER_NORMAL;
+        } else {
+            return QCOW2_CLUSTER_UNALLOCATED;
+        }
+    } else {
+        return QCOW2_CLUSTER_NORMAL;
+    }
+}
+
+/*
+ * In an image without subsclusters @l2_bitmap is ignored and
+ * @sc_index must be 0.
+ * Return QCOW2_SUBCLUSTER_INVALID if an invalid l2 entry is detected
+ * (this checks the whole entry and bitmap, not only the bits related
+ * to subcluster @sc_index).
+ */
+static inline
+QCow2SubclusterType qcow2_get_subcluster_type(BlockDriverState *bs,
+                                              uint64_t l2_entry,
+                                              uint64_t l2_bitmap,
+                                              unsigned sc_index)
+{
+    BDRVQcow2State *s = bs->opaque;
+    QCow2ClusterType type = qcow2_get_cluster_type(bs, l2_entry);
+    assert(sc_index < s->subclusters_per_cluster);
+
+    if (has_subclusters(s)) {
+        switch (type) {
+        case QCOW2_CLUSTER_COMPRESSED:
+            return QCOW2_SUBCLUSTER_COMPRESSED;
+        case QCOW2_CLUSTER_NORMAL:
+            if ((l2_bitmap >> 32) & l2_bitmap) {
+                return QCOW2_SUBCLUSTER_INVALID;
+            } else if (l2_bitmap & QCOW_OFLAG_SUB_ZERO(sc_index)) {
+                return QCOW2_SUBCLUSTER_ZERO_ALLOC;
+            } else if (l2_bitmap & QCOW_OFLAG_SUB_ALLOC(sc_index)) {
+                return QCOW2_SUBCLUSTER_NORMAL;
+            } else {
+                return QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC;
+            }
+        case QCOW2_CLUSTER_UNALLOCATED:
+            if (l2_bitmap & QCOW_L2_BITMAP_ALL_ALLOC) {
+                return QCOW2_SUBCLUSTER_INVALID;
+            } else if (l2_bitmap & QCOW_OFLAG_SUB_ZERO(sc_index)) {
+                return QCOW2_SUBCLUSTER_ZERO_PLAIN;
+            } else {
+                return QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN;
+            }
+        default:
+            g_assert_not_reached();
+        }
+    } else {
+        switch (type) {
+        case QCOW2_CLUSTER_COMPRESSED:
+            return QCOW2_SUBCLUSTER_COMPRESSED;
+        case QCOW2_CLUSTER_ZERO_PLAIN:
+            return QCOW2_SUBCLUSTER_ZERO_PLAIN;
+        case QCOW2_CLUSTER_ZERO_ALLOC:
+            return QCOW2_SUBCLUSTER_ZERO_ALLOC;
+        case QCOW2_CLUSTER_NORMAL:
+            return QCOW2_SUBCLUSTER_NORMAL;
+        case QCOW2_CLUSTER_UNALLOCATED:
+            return QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN;
+        default:
+            g_assert_not_reached();
+        }
+    }
+}
+
+static inline bool qcow2_cluster_is_allocated(QCow2ClusterType type)
+{
+    return (type == QCOW2_CLUSTER_COMPRESSED || type == QCOW2_CLUSTER_NORMAL ||
+            type == QCOW2_CLUSTER_ZERO_ALLOC);
+}
+
+/* Check whether refcounts are eager or lazy */
+static inline bool qcow2_need_accurate_refcounts(BDRVQcow2State *s)
+{
+    return !(s->incompatible_features & QCOW2_INCOMPAT_DIRTY);
+}
+
+static inline uint64_t l2meta_cow_start(QCowL2Meta *m)
+{
+    return m->offset + m->cow_start.offset;
+}
+
+static inline uint64_t l2meta_cow_end(QCowL2Meta *m)
+{
+    return m->offset + m->cow_end.offset + m->cow_end.nb_bytes;
+}
+
+static inline uint64_t refcount_diff(uint64_t r1, uint64_t r2)
+{
+    return r1 > r2 ? r1 - r2 : r2 - r1;
+}
+
+static inline
+uint32_t offset_to_reftable_index(BDRVQcow2State *s, uint64_t offset)
+{
+    return offset >> (s->refcount_block_bits + s->cluster_bits);
+}
+
+/* qcow2.c functions */
+int64_t qcow2_refcount_metadata_size(int64_t clusters, size_t cluster_size,
+                                     int refcount_order, bool generous_increase,
+                                     uint64_t *refblock_count);
+
+int qcow2_mark_dirty(BlockDriverState *bs);
+int qcow2_mark_corrupt(BlockDriverState *bs);
+int qcow2_mark_consistent(BlockDriverState *bs);
+int qcow2_update_header(BlockDriverState *bs);
+
+void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset,
+                             int64_t size, const char *message_format, ...)
+                             GCC_FMT_ATTR(5, 6);
+
+int qcow2_validate_table(BlockDriverState *bs, uint64_t offset,
+                         uint64_t entries, size_t entry_len,
+                         int64_t max_size_bytes, const char *table_name,
+                         Error **errp);
+
+/* qcow2-refcount.c functions */
+int qcow2_refcount_init(BlockDriverState *bs);
+void qcow2_refcount_close(BlockDriverState *bs);
+
+int qcow2_get_refcount(BlockDriverState *bs, int64_t cluster_index,
+                       uint64_t *refcount);
+
+int qcow2_update_cluster_refcount(BlockDriverState *bs, int64_t cluster_index,
+                                  uint64_t addend, bool decrease,
+                                  enum qcow2_discard_type type);
+
+int64_t qcow2_refcount_area(BlockDriverState *bs, uint64_t offset,
+                            uint64_t additional_clusters, bool exact_size,
+                            int new_refblock_index,
+                            uint64_t new_refblock_offset);
+
+int64_t qcow2_alloc_clusters(BlockDriverState *bs, uint64_t size);
+int64_t qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset,
+                                int64_t nb_clusters);
+int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size);
+void qcow2_free_clusters(BlockDriverState *bs,
+                          int64_t offset, int64_t size,
+                          enum qcow2_discard_type type);
+void qcow2_free_any_cluster(BlockDriverState *bs, uint64_t l2_entry,
+                            enum qcow2_discard_type type);
+
+int qcow2_update_snapshot_refcount(BlockDriverState *bs,
+    int64_t l1_table_offset, int l1_size, int addend);
+
+int coroutine_fn qcow2_flush_caches(BlockDriverState *bs);
+int coroutine_fn qcow2_write_caches(BlockDriverState *bs);
+int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
+                          BdrvCheckMode fix);
+
+void qcow2_process_discards(BlockDriverState *bs, int ret);
+
+int qcow2_check_metadata_overlap(BlockDriverState *bs, int ign, int64_t offset,
+                                 int64_t size);
+int qcow2_pre_write_overlap_check(BlockDriverState *bs, int ign, int64_t offset,
+                                  int64_t size, bool data_file);
+int qcow2_inc_refcounts_imrt(BlockDriverState *bs, BdrvCheckResult *res,
+                             void **refcount_table,
+                             int64_t *refcount_table_size,
+                             int64_t offset, int64_t size);
+
+int qcow2_change_refcount_order(BlockDriverState *bs, int refcount_order,
+                                BlockDriverAmendStatusCB *status_cb,
+                                void *cb_opaque, Error **errp);
+int qcow2_shrink_reftable(BlockDriverState *bs);
+int64_t qcow2_get_last_cluster(BlockDriverState *bs, int64_t size);
+int qcow2_detect_metadata_preallocation(BlockDriverState *bs);
+
+/* qcow2-cluster.c functions */
+int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size,
+                        bool exact_size);
+int qcow2_shrink_l1_table(BlockDriverState *bs, uint64_t max_size);
+int qcow2_write_l1_entry(BlockDriverState *bs, int l1_index);
+int qcow2_encrypt_sectors(BDRVQcow2State *s, int64_t sector_num,
+                          uint8_t *buf, int nb_sectors, bool enc, Error **errp);
+
+int qcow2_get_host_offset(BlockDriverState *bs, uint64_t offset,
+                          unsigned int *bytes, uint64_t *host_offset,
+                          QCow2SubclusterType *subcluster_type);
+int qcow2_alloc_host_offset(BlockDriverState *bs, uint64_t offset,
+                            unsigned int *bytes, uint64_t *host_offset,
+                            QCowL2Meta **m);
+int qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
+                                          uint64_t offset,
+                                          int compressed_size,
+                                          uint64_t *host_offset);
+void qcow2_parse_compressed_l2_entry(BlockDriverState *bs, uint64_t l2_entry,
+                                     uint64_t *coffset, int *csize);
+
+int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m);
+void qcow2_alloc_cluster_abort(BlockDriverState *bs, QCowL2Meta *m);
+int qcow2_cluster_discard(BlockDriverState *bs, uint64_t offset,
+                          uint64_t bytes, enum qcow2_discard_type type,
+                          bool full_discard);
+int qcow2_subcluster_zeroize(BlockDriverState *bs, uint64_t offset,
+                             uint64_t bytes, int flags);
+
+int qcow2_expand_zero_clusters(BlockDriverState *bs,
+                               BlockDriverAmendStatusCB *status_cb,
+                               void *cb_opaque);
+
+/* qcow2-snapshot.c functions */
+int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info);
+int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id);
+int qcow2_snapshot_delete(BlockDriverState *bs,
+                          const char *snapshot_id,
+                          const char *name,
+                          Error **errp);
+int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab);
+int qcow2_snapshot_load_tmp(BlockDriverState *bs,
+                            const char *snapshot_id,
+                            const char *name,
+                            Error **errp);
+
+void qcow2_free_snapshots(BlockDriverState *bs);
+int qcow2_read_snapshots(BlockDriverState *bs, Error **errp);
+int qcow2_write_snapshots(BlockDriverState *bs);
+
+int coroutine_fn qcow2_check_read_snapshot_table(BlockDriverState *bs,
+                                                 BdrvCheckResult *result,
+                                                 BdrvCheckMode fix);
+int coroutine_fn qcow2_check_fix_snapshot_table(BlockDriverState *bs,
+                                                BdrvCheckResult *result,
+                                                BdrvCheckMode fix);
+
+/* qcow2-cache.c functions */
+Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables,
+                               unsigned table_size);
+int qcow2_cache_destroy(Qcow2Cache *c);
+
+void qcow2_cache_entry_mark_dirty(Qcow2Cache *c, void *table);
+int qcow2_cache_flush(BlockDriverState *bs, Qcow2Cache *c);
+int qcow2_cache_write(BlockDriverState *bs, Qcow2Cache *c);
+int qcow2_cache_set_dependency(BlockDriverState *bs, Qcow2Cache *c,
+    Qcow2Cache *dependency);
+void qcow2_cache_depends_on_flush(Qcow2Cache *c);
+
+void qcow2_cache_clean_unused(Qcow2Cache *c);
+int qcow2_cache_empty(BlockDriverState *bs, Qcow2Cache *c);
+
+int qcow2_cache_get(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
+    void **table);
+int qcow2_cache_get_empty(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
+    void **table);
+void qcow2_cache_put(Qcow2Cache *c, void **table);
+void *qcow2_cache_is_table_offset(Qcow2Cache *c, uint64_t offset);
+void qcow2_cache_discard(Qcow2Cache *c, void *table);
+
+/* qcow2-bitmap.c functions */
+int qcow2_check_bitmaps_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
+                                  void **refcount_table,
+                                  int64_t *refcount_table_size);
+bool qcow2_load_dirty_bitmaps(BlockDriverState *bs, bool *header_updated,
+                              Error **errp);
+bool qcow2_get_bitmap_info_list(BlockDriverState *bs,
+                                Qcow2BitmapInfoList **info_list, Error **errp);
+int qcow2_reopen_bitmaps_rw(BlockDriverState *bs, Error **errp);
+int qcow2_truncate_bitmaps_check(BlockDriverState *bs, Error **errp);
+bool qcow2_store_persistent_dirty_bitmaps(BlockDriverState *bs,
+                                          bool release_stored, Error **errp);
+int qcow2_reopen_bitmaps_ro(BlockDriverState *bs, Error **errp);
+bool qcow2_co_can_store_new_dirty_bitmap(BlockDriverState *bs,
+                                         const char *name,
+                                         uint32_t granularity,
+                                         Error **errp);
+int qcow2_co_remove_persistent_dirty_bitmap(BlockDriverState *bs,
+                                            const char *name,
+                                            Error **errp);
+bool qcow2_supports_persistent_dirty_bitmap(BlockDriverState *bs);
+uint64_t qcow2_get_persistent_dirty_bitmap_size(BlockDriverState *bs,
+                                                uint32_t cluster_size);
+
+ssize_t coroutine_fn
+qcow2_co_compress(BlockDriverState *bs, void *dest, size_t dest_size,
+                  const void *src, size_t src_size);
+ssize_t coroutine_fn
+qcow2_co_decompress(BlockDriverState *bs, void *dest, size_t dest_size,
+                    const void *src, size_t src_size);
+int coroutine_fn
+qcow2_co_encrypt(BlockDriverState *bs, uint64_t host_offset,
+                 uint64_t guest_offset, void *buf, size_t len);
+int coroutine_fn
+qcow2_co_decrypt(BlockDriverState *bs, uint64_t host_offset,
+                 uint64_t guest_offset, void *buf, size_t len);
+
+#endif