diff options
| -rw-r--r-- | block/qcow2.h | 126 |
1 files changed, 125 insertions, 1 deletions
diff --git a/block/qcow2.h b/block/qcow2.h index 82b86f6cec..3aec6f452a 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -80,6 +80,21 @@ #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) @@ -462,6 +477,33 @@ typedef struct QCowL2Meta 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, @@ -470,6 +512,16 @@ typedef enum QCow2ClusterType { 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, @@ -634,9 +686,11 @@ static inline int64_t qcow2_vm_state_offset(BDRVQcow2State *s) 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) { + } else if ((l2_entry & QCOW_OFLAG_ZERO) && !has_subclusters(s)) { if (l2_entry & L2E_OFFSET_MASK) { return QCOW2_CLUSTER_ZERO_ALLOC; } @@ -656,6 +710,76 @@ static inline QCow2ClusterType qcow2_get_cluster_type(BlockDriverState *bs, } } +/* + * For an image without extended L2 entries, return the + * QCow2SubclusterType equivalent of a given QCow2ClusterType. + */ +static inline +QCow2SubclusterType qcow2_cluster_to_subcluster_type(QCow2ClusterType type) +{ + 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(); + } +} + +/* + * 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 { + return qcow2_cluster_to_subcluster_type(type); + } +} + /* Check whether refcounts are eager or lazy */ static inline bool qcow2_need_accurate_refcounts(BDRVQcow2State *s) { |