Merge "snapuserd: Restrict where reads/writes to dm_user_header happen." into... (bf724405) · Commits · e / os / android_system_core

fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_core.h

+0 −1

Original line number	Diff line number	Diff line
		@@ -119,7 +119,6 @@ class Worker {
		}

		// Functions interacting with dm-user
		bool ReadDmUserHeader();
		bool WriteDmUserPayload(size_t size);
		bool DmuserReadRequest();

fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_dm_user.cpp

+34 −50

Original line number	Diff line number	Diff line
		@@ -290,21 +290,6 @@ bool Worker::RunThread() {
		return true;
		}

		// Read Header from dm-user misc device. This gives
		// us the sector number for which IO is issued by dm-snapshot device
		bool Worker::ReadDmUserHeader() {
		if (!android::base::ReadFully(ctrl_fd_, bufsink_.GetBufPtr(), sizeof(struct dm_user_header))) {
		if (errno != ENOTBLK) {
		SNAP_PLOG(ERROR) << "Control-read failed";
		}

		SNAP_PLOG(DEBUG) << "ReadDmUserHeader failed....";
		return false;
		}

		return true;
		}

		// Send the payload/data back to dm-user misc device.
		bool Worker::WriteDmUserPayload(size_t size) {
		size_t payload_size = size;
		@@ -345,19 +330,15 @@ bool Worker::ReadDataFromBaseDevice(sector_t sector, size_t read_size) {
		}

		bool Worker::ReadAlignedSector(sector_t sector, size_t sz) {
		struct dm_user_header* header = bufsink_.GetHeaderPtr();
		size_t remaining_size = sz;
		std::vector<std::pair<sector_t, const CowOperation*>>& chunk_vec = snapuserd_->GetChunkVec();
		bool io_error = false;
		int ret = 0;

		do {
		// Process 1MB payload at a time
		size_t read_size = std::min(PAYLOAD_BUFFER_SZ, remaining_size);

		header->type = DM_USER_RESP_SUCCESS;
		size_t total_bytes_read = 0;
		io_error = false;
		bufsink_.ResetBufferOffset();

		while (read_size) {
		@@ -375,7 +356,7 @@ bool Worker::ReadAlignedSector(sector_t sector, size_t sz) {
		// device.
		if (!ReadDataFromBaseDevice(sector, size)) {
		SNAP_LOG(ERROR) << "ReadDataFromBaseDevice failed";
		header->type = DM_USER_RESP_ERROR;
		return false;
		}

		ret = size;
		@@ -384,26 +365,18 @@ bool Worker::ReadAlignedSector(sector_t sector, size_t sz) {
		// process it.
		if (!ProcessCowOp(it->second)) {
		SNAP_LOG(ERROR) << "ProcessCowOp failed";
		header->type = DM_USER_RESP_ERROR;
		return false;
		}

		ret = BLOCK_SZ;
		}

		// Just return the header if it is an error
		if (header->type == DM_USER_RESP_ERROR) {
		RespondIOError();
		io_error = true;
		break;
		}

		read_size -= ret;
		total_bytes_read += ret;
		sector += (ret >> SECTOR_SHIFT);
		bufsink_.UpdateBufferOffset(ret);
		}

		if (!io_error) {
		if (!WriteDmUserPayload(total_bytes_read)) {
		return false;
		}
		@@ -411,8 +384,7 @@ bool Worker::ReadAlignedSector(sector_t sector, size_t sz) {
		SNAP_LOG(DEBUG) << "WriteDmUserPayload success total_bytes_read: " << total_bytes_read
		<< " remaining_size: " << remaining_size;
		remaining_size -= total_bytes_read;
		}
		} while (remaining_size > 0 && !io_error);
		} while (remaining_size > 0);

		return true;
		}
		@@ -453,8 +425,6 @@ int Worker::ReadUnalignedSector(
		}

		bool Worker::ReadUnalignedSector(sector_t sector, size_t size) {
		struct dm_user_header* header = bufsink_.GetHeaderPtr();
		header->type = DM_USER_RESP_SUCCESS;
		bufsink_.ResetBufferOffset();
		std::vector<std::pair<sector_t, const CowOperation*>>& chunk_vec = snapuserd_->GetChunkVec();

		@@ -622,9 +592,15 @@ bool Worker::DmuserReadRequest() {
		}

		bool Worker::ProcessIORequest() {
		// Read Header from dm-user misc device. This gives
		// us the sector number for which IO is issued by dm-snapshot device
		struct dm_user_header* header = bufsink_.GetHeaderPtr();
		if (!android::base::ReadFully(ctrl_fd_, header, sizeof(*header))) {
		if (errno != ENOTBLK) {
		SNAP_PLOG(ERROR) << "Control-read failed";
		}

		if (!ReadDmUserHeader()) {
		SNAP_PLOG(DEBUG) << "ReadDmUserHeader failed....";
		return false;
		}

		@@ -634,26 +610,34 @@ bool Worker::ProcessIORequest() {
		SNAP_LOG(DEBUG) << "Daemon: msg->type: " << std::dec << header->type;
		SNAP_LOG(DEBUG) << "Daemon: msg->flags: " << std::dec << header->flags;

		// Use the same header buffer as the response header.
		int request_type = header->type;
		header->type = DM_USER_RESP_SUCCESS;
		header_response_ = true;

		switch (header->type) {
		case DM_USER_REQ_MAP_READ: {
		if (!DmuserReadRequest()) {
		return false;
		}
		bool ok;
		switch (request_type) {
		case DM_USER_REQ_MAP_READ:
		ok = DmuserReadRequest();
		break;
		}

		case DM_USER_REQ_MAP_WRITE: {
		case DM_USER_REQ_MAP_WRITE:
		// TODO: We should not get any write request
		// to dm-user as we mount all partitions
		// as read-only. Need to verify how are TRIM commands
		// handled during mount.
		return false;
		}
		ok = false;
		break;

		default:
		ok = false;
		break;
		}

		return true;
		if (!ok && header->type != DM_USER_RESP_ERROR) {
		RespondIOError();
		}
		return ok;
		}

		} // namespace snapshot