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authorMax Reitz <mreitz@redhat.com>2014-09-03 00:25:08 +0200
committerKevin Wolf <kwolf@redhat.com>2014-10-23 15:34:02 +0200
commit4b318d6ca66545e59eafbf595f66e31bf1625d9a (patch)
tree4076192f27a4cc6a4b7b163b9d6456f7d6a2f951 /docs
parent17bd5f472754acd2458b53dc02a30d5651e6dd79 (diff)
downloadqemu-4b318d6ca66545e59eafbf595f66e31bf1625d9a.zip
docs/qcow2: Correct refcount_block_entries
A refblock entry may have a different size than 16 bits, it may even be smaller than a byte. Correct the refcount_block_entries calculation accordingly. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'docs')
-rw-r--r--docs/specs/qcow2.txt2
1 files changed, 1 insertions, 1 deletions
diff --git a/docs/specs/qcow2.txt b/docs/specs/qcow2.txt
index cfbc8b070c..0a878aa95d 100644
--- a/docs/specs/qcow2.txt
+++ b/docs/specs/qcow2.txt
@@ -183,7 +183,7 @@ blocks and are exactly one cluster in size.
Given a offset into the image file, the refcount of its cluster can be obtained
as follows:
- refcount_block_entries = (cluster_size / sizeof(uint16_t))
+ refcount_block_entries = (cluster_size * 8 / refcount_bits)
refcount_block_index = (offset / cluster_size) % refcount_block_entries
refcount_table_index = (offset / cluster_size) / refcount_block_entries