[Qemu-devel] [PATCH v3 07/12] qcow2/overlaps: Protect active L1 table

[Max Reitz <mreitz@redhat.com>]

Keep track of the active L1 table in the metadata list to protect it
against accidental modifications.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 block/qcow2-cluster.c  | 11 +++++++++++
 block/qcow2-snapshot.c | 10 ++++++++++
 block/qcow2.c          |  4 ++++
 3 files changed, 25 insertions(+)

diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 183177d..bc93c00 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -125,6 +125,17 @@ int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size,
     s->l1_table = new_l1_table;
     old_l1_size = s->l1_size;
     s->l1_size = new_l1_size;
+
+    qcow2_metadata_list_remove(bs, old_l1_table_offset,
+                               size_to_clusters(s, old_l1_size *
+                                                   sizeof(uint64_t)),
+                               QCOW2_OL_ACTIVE_L1);
+
+    qcow2_metadata_list_enter(bs, s->l1_table_offset,
+                              size_to_clusters(s, s->l1_size *
+                                                  sizeof(uint64_t)),
+                              QCOW2_OL_ACTIVE_L1);
+
     qcow2_free_clusters(bs, old_l1_table_offset, old_l1_size * sizeof(uint64_t),
                         QCOW2_DISCARD_OTHER);
     return 0;
diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c
index 5b3903c..41ea053 100644
--- a/block/qcow2-snapshot.c
+++ b/block/qcow2-snapshot.c
@@ -720,6 +720,11 @@ int qcow2_snapshot_load_tmp(BlockDriverState *bs,
         return ret;
     }
 
+    qcow2_metadata_list_remove(bs, s->l1_table_offset,
+                               size_to_clusters(s, s->l1_size *
+                                                   sizeof(uint64_t)),
+                               QCOW2_OL_ACTIVE_L1);
+
     /* Switch the L1 table */
     qemu_vfree(s->l1_table);
 
@@ -731,5 +736,10 @@ int qcow2_snapshot_load_tmp(BlockDriverState *bs,
         be64_to_cpus(&s->l1_table[i]);
     }
 
+    qcow2_metadata_list_enter(bs, s->l1_table_offset,
+                              size_to_clusters(s, s->l1_size *
+                                                  sizeof(uint64_t)),
+                              QCOW2_OL_ACTIVE_L1);
+
     return 0;
 }
diff --git a/block/qcow2.c b/block/qcow2.c
index e9f4824..f285555 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -832,6 +832,10 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags,
     }
     s->l1_table_offset = header.l1_table_offset;
 
+    qcow2_metadata_list_enter(bs, s->l1_table_offset,
+                              size_to_clusters(s, s->l1_size *
+                                                  sizeof(uint64_t)),
+                              QCOW2_OL_ACTIVE_L1);
 
     if (s->l1_size > 0) {
         s->l1_table = qemu_try_blockalign(bs->file,
-- 
2.1.0