diff options
Diffstat (limited to 'block/qcow2-refcount.c')
| -rw-r--r-- | block/qcow2-refcount.c | 30 |
1 files changed, 19 insertions, 11 deletions
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c index 2fdc26b612..933311c5ec 100644 --- a/block/qcow2-refcount.c +++ b/block/qcow2-refcount.c @@ -123,6 +123,24 @@ static int get_refcount(BlockDriverState *bs, int64_t cluster_index) return be16_to_cpu(s->refcount_block_cache[block_index]); } +/* + * Rounds the refcount table size up to avoid growing the table for each single + * refcount block that is allocated. + */ +static unsigned int next_refcount_table_size(BDRVQcowState *s, + unsigned int min_size) +{ + unsigned int min_clusters = (min_size >> (s->cluster_bits - 3)) + 1; + unsigned int refcount_table_clusters = + MAX(1, s->refcount_table_size >> (s->cluster_bits - 3)); + + while (min_clusters > refcount_table_clusters) { + refcount_table_clusters = (refcount_table_clusters * 3 + 1) / 2; + } + + return refcount_table_clusters << (s->cluster_bits - 3); +} + static int grow_refcount_table(BlockDriverState *bs, int min_size) { BDRVQcowState *s = bs->opaque; @@ -136,17 +154,7 @@ static int grow_refcount_table(BlockDriverState *bs, int min_size) if (min_size <= s->refcount_table_size) return 0; /* compute new table size */ - refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3); - for(;;) { - if (refcount_table_clusters == 0) { - refcount_table_clusters = 1; - } else { - refcount_table_clusters = (refcount_table_clusters * 3 + 1) / 2; - } - new_table_size = refcount_table_clusters << (s->cluster_bits - 3); - if (min_size <= new_table_size) - break; - } + new_table_size = next_refcount_table_size(s, min_size); #ifdef DEBUG_ALLOC2 printf("grow_refcount_table from %d to %d\n", s->refcount_table_size, |