Merge changes I0b9ce272,I2bb3e55b

* changes:
  libsnapshot: Ignore non-data ops in snapshot_reader.
  libsnapshot: Round compressed COW sizes to the nearest block.

Author: dvandercorp

fs_mgr/libsnapshot/partition_cow_creator.cpp

@@ -35,6 +35,8 @@ using RepeatedPtrField = google::protobuf::RepeatedPtrField<T>;
 namespace android {
 namespace snapshot {
 
+static constexpr uint64_t kBlockSize = 4096;
+
 using namespace android::storage_literals;
 
 // Intersect two linear extents. If no intersection, return an extent with length 0.
@@ -149,7 +151,12 @@ uint64_t PartitionCowCreator::GetCowSize() {
 
         // Add an extra 2MB of wiggle room for any minor differences in labels/metadata
         // that might come up.
-        return update->estimate_cow_size() + 2_MiB;
+        auto size = update->estimate_cow_size() + 2_MiB;
+
+        // Align to nearest block.
+        size += kBlockSize - 1;
+        size &= ~(kBlockSize - 1);
+        return size;
     }
 
     // WARNING: The origin partition should be READ-ONLY

fs_mgr/libsnapshot/snapshot_reader.cpp

@@ -90,6 +90,9 @@ bool CompressedSnapshotReader::SetCow(std::unique_ptr<CowReader>&& cow) {
     op_iter_ = cow_->GetOpIter();
     while (!op_iter_->Done()) {
         const CowOperation* op = &op_iter_->Get();
+        if (op->type == kCowLabelOp || op->type == kCowFooterOp) {
+            continue;
+        }
         if (op->new_block >= ops_.size()) {
             ops_.resize(op->new_block + 1, nullptr);
         }
@@ -274,7 +277,7 @@ ssize_t CompressedSnapshotReader::ReadBlock(uint64_t chunk, IByteSink* sink, siz
             return -1;
         }
     } else {
-        LOG(ERROR) << "CompressedSnapshotReader unknown op type: " << op->type;
+        LOG(ERROR) << "CompressedSnapshotReader unknown op type: " << uint32_t(op->type);
         errno = EINVAL;
         return -1;
     }