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| author | Max Reitz <mreitz@redhat.com> | 2013-08-30 10:40:14 +0200 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2013-08-30 15:28:52 +0200 |
| commit | 8b81a7b6ba8686f35f9cb0acdd54004d63206f03 (patch) | |
| tree | 9676950cef9e6f2b37e03883a9c9f67083e61ff7 /block | |
| parent | d4ca092a423f1f853a99357bab01a168bb57d625 (diff) | |
| download | qemu-8b81a7b6ba8686f35f9cb0acdd54004d63206f03.zip qemu-8b81a7b6ba8686f35f9cb0acdd54004d63206f03.tar.gz qemu-8b81a7b6ba8686f35f9cb0acdd54004d63206f03.tar.bz2 | |
qcow2-refcount: Snapshot update for zero clusters
Account for all cluster types in qcow2_update_snapshot_refcounts;
this prevents this function from updating the refcount of unallocated
zero clusters which effectively led to wrong adjustments of the refcount
of cluster 0 (the main qcow2 header). This in turn resulted in images
with (unallocated) zero clusters having a cluster 0 refcount greater
than one after creating a snapshot.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block')
| -rw-r--r-- | block/qcow2-refcount.c | 52 |
1 files changed, 35 insertions, 17 deletions
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c index 1244693..a61224a 100644 --- a/block/qcow2-refcount.c +++ b/block/qcow2-refcount.c @@ -861,11 +861,14 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs, } for(j = 0; j < s->l2_size; j++) { + uint64_t cluster_index; + offset = be64_to_cpu(l2_table[j]); - if (offset != 0) { - old_offset = offset; - offset &= ~QCOW_OFLAG_COPIED; - if (offset & QCOW_OFLAG_COMPRESSED) { + old_offset = offset; + offset &= ~QCOW_OFLAG_COPIED; + + switch (qcow2_get_cluster_type(offset)) { + case QCOW2_CLUSTER_COMPRESSED: nb_csectors = ((offset >> s->csize_shift) & s->csize_mask) + 1; if (addend != 0) { @@ -880,8 +883,16 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs, } /* compressed clusters are never modified */ refcount = 2; - } else { - uint64_t cluster_index = (offset & L2E_OFFSET_MASK) >> s->cluster_bits; + break; + + case QCOW2_CLUSTER_NORMAL: + case QCOW2_CLUSTER_ZERO: + cluster_index = (offset & L2E_OFFSET_MASK) >> s->cluster_bits; + if (!cluster_index) { + /* unallocated */ + refcount = 0; + break; + } if (addend != 0) { refcount = update_cluster_refcount(bs, cluster_index, addend, QCOW2_DISCARD_SNAPSHOT); @@ -893,19 +904,26 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs, ret = refcount; goto fail; } - } + break; - if (refcount == 1) { - offset |= QCOW_OFLAG_COPIED; - } - if (offset != old_offset) { - if (addend > 0) { - qcow2_cache_set_dependency(bs, s->l2_table_cache, - s->refcount_block_cache); - } - l2_table[j] = cpu_to_be64(offset); - qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table); + case QCOW2_CLUSTER_UNALLOCATED: + refcount = 0; + break; + + default: + abort(); + } + + if (refcount == 1) { + offset |= QCOW_OFLAG_COPIED; + } + if (offset != old_offset) { + if (addend > 0) { + qcow2_cache_set_dependency(bs, s->l2_table_cache, + s->refcount_block_cache); } + l2_table[j] = cpu_to_be64(offset); + qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table); } } |