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From 4d45b1791fb8bc24c17045a91b39c1d62e9e47c3 Mon Sep 17 00:00:00 2001
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From: Max Reitz <mreitz@redhat.com>
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Date: Tue, 7 Jan 2014 21:57:07 +0100
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Subject: [PATCH 02/14] qcow2-refcount: Snapshot update for zero clusters
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RH-Author: Max Reitz <mreitz@redhat.com>
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Message-id: <1389131839-12920-3-git-send-email-mreitz@redhat.com>
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Patchwork-id: 56538
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O-Subject: [RHEL-7.0 qemu-kvm PATCH v2 02/14] qcow2-refcount: Snapshot update for zero clusters
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Bugzilla: 1033490
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RH-Acked-by: Kevin Wolf <kwolf@redhat.com>
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RH-Acked-by: Fam Zheng <famz@redhat.com>
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RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
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BZ: 1033490
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Account for all cluster types in qcow2_update_snapshot_refcounts;
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this prevents this function from updating the refcount of unallocated
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zero clusters which effectively led to wrong adjustments of the refcount
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of cluster 0 (the main qcow2 header). This in turn resulted in images
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with (unallocated) zero clusters having a cluster 0 refcount greater
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than one after creating a snapshot.
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Signed-off-by: Max Reitz <mreitz@redhat.com>
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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(cherry picked from commit 8b81a7b6ba8686f35f9cb0acdd54004d63206f03)
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Signed-off-by: Max Reitz <mreitz@redhat.com>
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---
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block/qcow2-refcount.c | 52 +++++++++++++++++++++++++++++++++-----------------
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1 file changed, 35 insertions(+), 17 deletions(-)
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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block/qcow2-refcount.c | 52 ++++++++++++++++++++++++++++++++---------------
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1 files changed, 35 insertions(+), 17 deletions(-)
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diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
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index 3787314..2b72d5e 100644
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--- a/block/qcow2-refcount.c
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+++ b/block/qcow2-refcount.c
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@@ -863,11 +863,14 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs,
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}
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for(j = 0; j < s->l2_size; j++) {
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+ uint64_t cluster_index;
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+
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offset = be64_to_cpu(l2_table[j]);
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- if (offset != 0) {
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- old_offset = offset;
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- offset &= ~QCOW_OFLAG_COPIED;
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- if (offset & QCOW_OFLAG_COMPRESSED) {
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+ old_offset = offset;
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+ offset &= ~QCOW_OFLAG_COPIED;
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+
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+ switch (qcow2_get_cluster_type(offset)) {
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+ case QCOW2_CLUSTER_COMPRESSED:
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nb_csectors = ((offset >> s->csize_shift) &
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s->csize_mask) + 1;
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if (addend != 0) {
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@@ -882,8 +885,16 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs,
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}
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/* compressed clusters are never modified */
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refcount = 2;
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- } else {
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- uint64_t cluster_index = (offset & L2E_OFFSET_MASK) >> s->cluster_bits;
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+ break;
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+
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+ case QCOW2_CLUSTER_NORMAL:
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+ case QCOW2_CLUSTER_ZERO:
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+ cluster_index = (offset & L2E_OFFSET_MASK) >> s->cluster_bits;
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+ if (!cluster_index) {
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+ /* unallocated */
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+ refcount = 0;
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+ break;
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+ }
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if (addend != 0) {
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refcount = update_cluster_refcount(bs, cluster_index, addend,
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QCOW2_DISCARD_SNAPSHOT);
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@@ -895,19 +906,26 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs,
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ret = refcount;
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goto fail;
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}
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- }
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+ break;
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- if (refcount == 1) {
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- offset |= QCOW_OFLAG_COPIED;
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- }
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- if (offset != old_offset) {
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- if (addend > 0) {
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- qcow2_cache_set_dependency(bs, s->l2_table_cache,
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- s->refcount_block_cache);
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- }
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- l2_table[j] = cpu_to_be64(offset);
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- qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table);
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+ case QCOW2_CLUSTER_UNALLOCATED:
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+ refcount = 0;
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+ break;
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+
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+ default:
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+ abort();
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+ }
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+
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+ if (refcount == 1) {
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+ offset |= QCOW_OFLAG_COPIED;
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+ }
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+ if (offset != old_offset) {
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+ if (addend > 0) {
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+ qcow2_cache_set_dependency(bs, s->l2_table_cache,
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+ s->refcount_block_cache);
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}
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+ l2_table[j] = cpu_to_be64(offset);
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+ qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table);
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}
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}
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--
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1.7.1
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