diff options
Diffstat (limited to 'block-qcow2.c')
-rw-r--r-- | block-qcow2.c | 36 |
1 files changed, 28 insertions, 8 deletions
diff --git a/block-qcow2.c b/block-qcow2.c index 7c00ee8..8a5b621 100644 --- a/block-qcow2.c +++ b/block-qcow2.c @@ -145,6 +145,7 @@ typedef struct BDRVQcowState { AES_KEY aes_decrypt_key; int64_t highest_alloc; /* highest cluester allocated (in clusters) */ + int64_t nc_free; /* num of free clusters below highest_alloc */ uint64_t snapshots_offset; int snapshots_size; @@ -173,7 +174,7 @@ 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 void scan_refcount(BlockDriverState *bs, int64_t *high, int64_t *free); static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename) @@ -283,7 +284,7 @@ static int qcow_open(BlockDriverState *bs, const char *filename, int flags) if (refcount_init(bs) < 0) goto fail; - scan_refcount(bs, &s->highest_alloc); + scan_refcount(bs, &s->highest_alloc, &s->nc_free); /* read the backing file name */ if (header.backing_file_offset != 0) { @@ -1672,6 +1673,7 @@ static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) bdi->vm_state_offset = (int64_t)s->l1_vm_state_index << (s->cluster_bits + s->l2_bits); bdi->highest_alloc = s->highest_alloc << s->cluster_bits; + bdi->num_free_bytes = s->nc_free << s->cluster_bits; return 0; } @@ -2214,25 +2216,35 @@ static int load_refcount_block(BlockDriverState *bs, return 0; } -static void scan_refcount(BlockDriverState *bs, int64_t *high) +static void scan_refcount(BlockDriverState *bs, int64_t *high, int64_t *free) { BDRVQcowState *s = bs->opaque; - int64_t refcnt_index, cluster_index, cluster_end, h = 0; + int64_t refcnt_index, cluster_index, cluster_end, h = 0, f = 0; + int64_t tail = 0; /* do not count last consecutive free entries */ for (refcnt_index=0; refcnt_index < s->refcount_table_size; refcnt_index++){ if (s->refcount_table[refcnt_index] == 0) { + f += 1 << (s->cluster_bits - REFCOUNT_SHIFT); + tail += 1 << (s->cluster_bits - REFCOUNT_SHIFT); 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 + if (get_refcount(bs, cluster_index) == 0) { + f++; + tail++; + } + else { h = cluster_index; + tail = 0; + } } } + f -= tail; + if (free) + *free = f; if (high) *high = (h+1); } @@ -2278,8 +2290,10 @@ retry: (s->free_cluster_index - nb_clusters) << s->cluster_bits); #endif - if (s->highest_alloc < s->free_cluster_index) + if (s->highest_alloc < s->free_cluster_index) { + s->nc_free += (s->free_cluster_index - s->highest_alloc); s->highest_alloc = s->free_cluster_index; + } return (s->free_cluster_index - nb_clusters) << s->cluster_bits; } @@ -2456,6 +2470,12 @@ static int update_cluster_refcount(BlockDriverState *bs, block_index = cluster_index & ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1); refcount = be16_to_cpu(s->refcount_block_cache[block_index]); + + if (refcount == 1 && addend == -1) + s->nc_free += 1; + else if (refcount == 0 && addend == 1) + s->nc_free -= 1; + refcount += addend; if (refcount < 0 || refcount > 0xffff) return -EINVAL; |