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Date: Mon, 9 Nov 2009 15:52:55 +0530
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From: Furquan Shaikh <furquan.m.shaikh@gmail.com>
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Subject: [Qemu-devel] Doubt about COW feature of QCOW2
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Hello All,
I had a doubt about the COW implementation of QCOW2.

Suppose two clusters point to the same address, then in that case, the
QCOW_OFLAG_COPIED is cleared in the l2 entries for both the clusters.
Now suppose a write is made to any one of the clusters, then how is the
other cluster identified, in order to set the QCOW_OFLAG_COPIED since only
reference is left.

Thanks in advance,
Furquan

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Hello All,<br>I had a doubt about the COW implementation of QCOW2.<br><br>S=
uppose two clusters point to the same address, then in that case, the QCOW_=
OFLAG_COPIED is cleared in the l2 entries for both the clusters. <br>Now su=
ppose a write is made to any one of the clusters, then how is the other clu=
ster identified, in order to set the QCOW_OFLAG_COPIED since only reference=
 is left.<br>
<br>Thanks in advance,<br>Furquan<br>

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