Extended L2 entries are 128-bit wide: 64 bits for the entry itself and
64 bits for the subcluster allocation bitmap.
In order to support them correctly get/set_l2_entry() need to be
updated so they take the entry width into account in order to
calculate the correct offset.
This patch also adds the get/set_l2_bitmap() functions that are
used to access the bitmaps. For convenience we allow calling
get_l2_bitmap() on images without subclusters, although the caller
does not need and should ignore the returned value.
Signed-off-by: Alberto Garcia <be...@igalia.com>
---
block/qcow2.h | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
diff --git a/block/qcow2.h b/block/qcow2.h
index 8be020bb76..64b0a814f4 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -518,15 +518,37 @@ static inline size_t l2_entry_size(BDRVQcow2State *s)
static inline uint64_t get_l2_entry(BDRVQcow2State *s, uint64_t *l2_slice,
int idx)
{
+ idx *= l2_entry_size(s) / sizeof(uint64_t);
return be64_to_cpu(l2_slice[idx]);
}
+static inline uint64_t get_l2_bitmap(BDRVQcow2State *s, uint64_t *l2_slice,
+ int idx)
+{
+ if (has_subclusters(s)) {
+ idx *= l2_entry_size(s) / sizeof(uint64_t);
+ return be64_to_cpu(l2_slice[idx + 1]);
+ } else {
+ /* For convenience only; the caller should ignore this value. */
+ return 0;
+ }
+}
+
static inline void set_l2_entry(BDRVQcow2State *s, uint64_t *l2_slice,
int idx, uint64_t entry)
{
+ idx *= l2_entry_size(s) / sizeof(uint64_t);
l2_slice[idx] = cpu_to_be64(entry);
}
+static inline void set_l2_bitmap(BDRVQcow2State *s, uint64_t *l2_slice,
+ int idx, uint64_t bitmap)
+{
+ assert(has_subclusters(s));
+ idx *= l2_entry_size(s) / sizeof(uint64_t);
+ l2_slice[idx + 1] = cpu_to_be64(bitmap);
+}
+
static inline bool has_data_file(BlockDriverState *bs)
{
BDRVQcow2State *s = bs->opaque;
--
2.20.1
