qcow2: Add offset_to_l2_slice_index()

Similar to offset_to_l2_index(), this function takes a guest offset
and returns the index in the L2 slice that contains its L2 entry.

An L2 slice has currently the same size as an L2 table (one cluster),
so both functions return the same value for now.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: a1c45c5c5a76146dd1712d8d1e7b409ad539c718.1517840877.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>

diff --git a/block/qcow2.h b/block/qcow2.h
index 45fb7f429980c120f9c0bc5b88029a32c1640b3b..d956a6cdd25551ea7154b71b1ab752ddf979fa62 100644 (file)
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -474,6 +474,11 @@ static inline int offset_to_l2_index(BDRVQcow2State *s, int64_t offset)
     return (offset >> s->cluster_bits) & (s->l2_size - 1);
 }
 
+static inline int offset_to_l2_slice_index(BDRVQcow2State *s, int64_t offset)
+{
+    return (offset >> s->cluster_bits) & (s->l2_slice_size - 1);
+}
+
 static inline int64_t align_offset(int64_t offset, int n)
 {
     offset = (offset + n - 1) & ~(n - 1);