diff options
| -rw-r--r-- | block-qcow2.c | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/block-qcow2.c b/block-qcow2.c index d4556efa4e..e016e8f004 100644 --- a/block-qcow2.c +++ b/block-qcow2.c @@ -143,6 +143,9 @@ typedef struct BDRVQcowState { uint32_t crypt_method_header; AES_KEY aes_encrypt_key; AES_KEY aes_decrypt_key; + + int64_t highest_alloc; /* highest cluester allocated (in clusters) */ + uint64_t snapshots_offset; int snapshots_size; int nb_snapshots; @@ -170,6 +173,8 @@ static void free_clusters(BlockDriverState *bs, #ifdef DEBUG_ALLOC static void check_refcounts(BlockDriverState *bs); #endif +static void scan_refcount(BlockDriverState *bs, int64_t *high); + static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename) { @@ -278,6 +283,8 @@ static int qcow_open(BlockDriverState *bs, const char *filename, int flags) if (refcount_init(bs) < 0) goto fail; + scan_refcount(bs, &s->highest_alloc); + /* read the backing file name */ if (header.backing_file_offset != 0) { len = header.backing_file_size; @@ -2206,6 +2213,29 @@ static int load_refcount_block(BlockDriverState *bs, return 0; } +static void scan_refcount(BlockDriverState *bs, int64_t *high) +{ + BDRVQcowState *s = bs->opaque; + int64_t refcnt_index, cluster_index, cluster_end, h = 0; + + for (refcnt_index=0; refcnt_index < s->refcount_table_size; refcnt_index++){ + if (s->refcount_table[refcnt_index] == 0) { + continue; + } + cluster_index = refcnt_index << (s->cluster_bits - REFCOUNT_SHIFT); + cluster_end = (refcnt_index + 1) << (s->cluster_bits - REFCOUNT_SHIFT); + for ( ; cluster_index < cluster_end; cluster_index++) { + if (get_refcount(bs, cluster_index) == 0) + /* do nothing -- reserved for free counting */; + else + h = cluster_index; + } + } + + if (high) + *high = (h+1); +} + static int get_refcount(BlockDriverState *bs, int64_t cluster_index) { BDRVQcowState *s = bs->opaque; @@ -2246,6 +2276,10 @@ retry: size, (s->free_cluster_index - nb_clusters) << s->cluster_bits); #endif + + if (s->highest_alloc < s->free_cluster_index) + s->highest_alloc = s->free_cluster_index; + return (s->free_cluster_index - nb_clusters) << s->cluster_bits; } |