When every item of refcount block is NULL, free refcount block and reset the
corresponding item of refcount table with NULL. At the same time, put this
cluster to s->free_cluster_index.
Signed-off-by: Jun Li <junm...@gmail.com>
---
v4:
Do not change anything for this commit id.
v3:
Add handle self-describing refcount blocks.
---
block/qcow2-refcount.c | 46 +++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 45 insertions(+), 1 deletion(-)
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index 2bcaaf9..b603d4e 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -28,6 +28,7 @@
#include "qemu/range.h"
static int64_t alloc_clusters_noref(BlockDriverState *bs, uint64_t size);
+static int write_reftable_entry(BlockDriverState *bs, int rt_index);
static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs,
int64_t offset, int64_t length,
int addend, enum qcow2_discard_type type);
@@ -599,6 +600,49 @@ static int QEMU_WARN_UNUSED_RESULT
update_refcount(BlockDriverState *bs,
if (refcount == 0 && s->discard_passthrough[type]) {
update_refcount_discard(bs, cluster_offset, s->cluster_size);
}
+
+ unsigned int refcount_table_index;
+ refcount_table_index = cluster_index >> (s->cluster_bits -
+ REFCOUNT_SHIFT);
+
+ uint64_t refcount_block_offset =
+ s->refcount_table[refcount_table_index] & REFT_OFFSET_MASK;
+
+ int64_t self_block_index = refcount_block_offset >> s->cluster_bits;
+ int self_block_index2 = (refcount_block_offset >> s->cluster_bits) &
+ ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1);
+
+ /* When refcount block is NULL, update refcount table */
+ if (!be16_to_cpu(refcount_block[0]) || self_block_index2 == 0) {
+ int k;
+ int refcount_block_entries = s->cluster_size /
+ sizeof(refcount_block[0]);
+ for (k = 0; k < refcount_block_entries; k++) {
+ if (k == self_block_index2) {
+ k++;
+ }
+
+ if (be16_to_cpu(refcount_block[k])) {
+ break;
+ }
+ }
+
+ if (k == refcount_block_entries) {
+ if (self_block_index < s->free_cluster_index) {
+ s->free_cluster_index = self_block_index;
+ }
+
+ /* update refcount table */
+ s->refcount_table[refcount_table_index] = 0;
+ ret = write_reftable_entry(bs, refcount_table_index);
+ if (ret < 0) {
+ fprintf(stderr, "Could not update refcount table: %s\n",
+ strerror(-ret));
+ goto fail;
+ }
+
+ }
+ }
}
ret = 0;
@@ -1184,7 +1228,7 @@ static int check_refcounts_l2(BlockDriverState *bs,
BdrvCheckResult *res,
case QCOW2_CLUSTER_NORMAL:
{
- uint64_t offset = l2_entry & L2E_OFFSET_MASK;
+ uint64_t offset = (uint64_t)(l2_entry & L2E_OFFSET_MASK);
if (flags & CHECK_FRAG_INFO) {
res->bfi.allocated_clusters++;
--
1.9.3
