summaryrefslogtreecommitdiff
path: root/block
diff options
context:
space:
mode:
Diffstat (limited to 'block')
-rw-r--r--block/qcow2.c40
1 files changed, 36 insertions, 4 deletions
diff --git a/block/qcow2.c b/block/qcow2.c
index ba946e6cbc..619b923142 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -2578,6 +2578,9 @@ static int update_refcount(BlockDriverState *bs,
{
BDRVQcowState *s = bs->opaque;
int64_t start, last, cluster_offset;
+ int64_t refcount_block_offset = 0;
+ int64_t table_index = -1, old_table_index;
+ int first_index = -1, last_index = -1;
#ifdef DEBUG_ALLOC2
printf("update_refcount: offset=%lld size=%lld addend=%d\n",
@@ -2590,10 +2593,25 @@ static int update_refcount(BlockDriverState *bs,
for(cluster_offset = start; cluster_offset <= last;
cluster_offset += s->cluster_size)
{
- int64_t refcount_block_offset;
int block_index, refcount;
int64_t cluster_index = cluster_offset >> s->cluster_bits;
+ /* Only write refcount block to disk when we are done with it */
+ old_table_index = table_index;
+ table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT);
+ if ((old_table_index >= 0) && (table_index != old_table_index)) {
+ size_t size = (last_index - first_index + 1) << REFCOUNT_SHIFT;
+ if (bdrv_pwrite(s->hd,
+ refcount_block_offset + (first_index << REFCOUNT_SHIFT),
+ &s->refcount_block_cache[first_index], size) != size)
+ {
+ return -EIO;
+ }
+
+ first_index = -1;
+ last_index = -1;
+ }
+
/* Load the refcount block and allocate it if needed */
refcount_block_offset = alloc_refcount_block(bs, cluster_index);
if (refcount_block_offset < 0) {
@@ -2603,6 +2621,13 @@ static int update_refcount(BlockDriverState *bs,
/* we can update the count and save it */
block_index = cluster_index &
((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1);
+ if (first_index == -1 || block_index < first_index) {
+ first_index = block_index;
+ }
+ if (block_index > last_index) {
+ last_index = block_index;
+ }
+
refcount = be16_to_cpu(s->refcount_block_cache[block_index]);
refcount += addend;
if (refcount < 0 || refcount > 0xffff)
@@ -2611,12 +2636,19 @@ static int update_refcount(BlockDriverState *bs,
s->free_cluster_index = cluster_index;
}
s->refcount_block_cache[block_index] = cpu_to_be16(refcount);
+ }
+
+ /* Write last changed block to disk */
+ if (refcount_block_offset != 0) {
+ size_t size = (last_index - first_index + 1) << REFCOUNT_SHIFT;
if (bdrv_pwrite(s->hd,
- refcount_block_offset + (block_index << REFCOUNT_SHIFT),
- &s->refcount_block_cache[block_index], 2) != 2)
+ refcount_block_offset + (first_index << REFCOUNT_SHIFT),
+ &s->refcount_block_cache[first_index], size) != size)
+ {
return -EIO;
-
+ }
}
+
return 0;
}