Add op count check before attempting to write operations (73ac5f18) · Commits · e / os / android_system_core

fs_mgr/libsnapshot/libsnapshot_cow/writer_v3.cpp

+26 −1

Original line number	Diff line number	Diff line
		@@ -216,7 +216,23 @@ bool CowWriterV3::OpenForAppend(uint64_t label) {
		return true;
		}

		bool CowWriterV3::CheckOpCount(size_t op_count) {
		if (IsEstimating()) {
		return true;
		}
		if (header_.op_count + op_count > header_.op_count_max) {
		LOG(ERROR) << "Current number of ops on disk: " << header_.op_count
		<< ", number of ops attempting to write: " << op_count
		<< ", this will exceed max op count " << header_.op_count_max;
		return false;
		}
		return true;
		}

		bool CowWriterV3::EmitCopy(uint64_t new_block, uint64_t old_block, uint64_t num_blocks) {
		if (!CheckOpCount(num_blocks)) {
		return false;
		}
		std::vector<CowOperationV3> ops(num_blocks);
		for (size_t i = 0; i < num_blocks; i++) {
		CowOperationV3& op = ops[i];
		@@ -232,11 +248,17 @@ bool CowWriterV3::EmitCopy(uint64_t new_block, uint64_t old_block, uint64_t num_
		}

		bool CowWriterV3::EmitRawBlocks(uint64_t new_block_start, const void* data, size_t size) {
		if (!CheckOpCount(size / header_.block_size)) {
		return false;
		}
		return EmitBlocks(new_block_start, data, size, 0, 0, kCowReplaceOp);
		}

		bool CowWriterV3::EmitXorBlocks(uint32_t new_block_start, const void* data, size_t size,
		uint32_t old_block, uint16_t offset) {
		if (!CheckOpCount(size / header_.block_size)) {
		return false;
		}
		return EmitBlocks(new_block_start, data, size, old_block, offset, kCowXorOp);
		}

		@@ -313,8 +335,11 @@ bool CowWriterV3::EmitBlocks(uint64_t new_block_start, const void* data, size_t
		}

		bool CowWriterV3::EmitZeroBlocks(uint64_t new_block_start, const uint64_t num_blocks) {
		if (!CheckOpCount(num_blocks)) {
		return false;
		}
		std::vector<CowOperationV3> ops(num_blocks);
		for (uint64_t i = 0; i < ops.size(); i++) {
		for (uint64_t i = 0; i < num_blocks; i++) {
		auto& op = ops[i];
		op.set_type(kCowZeroOp);
		op.new_block = new_block_start + i;

fs_mgr/libsnapshot/libsnapshot_cow/writer_v3.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -53,6 +53,7 @@ class CowWriterV3 : public CowWriterBase {
		bool EmitBlocks(uint64_t new_block_start, const void* data, size_t size, uint64_t old_block,
		uint16_t offset, CowOperationType type);
		bool CompressBlocks(size_t num_blocks, const void* data);
		bool CheckOpCount(size_t op_count);

		private:
		CowHeaderV3 header_{};