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[Qemu-devel] [PATCH v2 2/3] docs/qcow2: Correct refcount_block_entries
From: |
Max Reitz |
Subject: |
[Qemu-devel] [PATCH v2 2/3] docs/qcow2: Correct refcount_block_entries |
Date: |
Wed, 3 Sep 2014 00:25:08 +0200 |
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 <address@hidden>
---
docs/specs/qcow2.txt | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/docs/specs/qcow2.txt b/docs/specs/qcow2.txt
index cfbc8b0..0a878aa 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
--
2.1.0