Improved libdm and dmctl to handle very large numbers of extents
Enables performance testing with very large numbers of dm-linear devices
Test: Can create device with 16384 extents, and can get its table
Bug: 123261135
Change-Id: I0e78a659eb7616e4db6a8276031e25a0d84f52ba
diff --git a/fs_mgr/libdm/dm.cpp b/fs_mgr/libdm/dm.cpp
index c6a9e0b..a4614d0 100644
--- a/fs_mgr/libdm/dm.cpp
+++ b/fs_mgr/libdm/dm.cpp
@@ -299,24 +299,25 @@
// private methods of DeviceMapper
bool DeviceMapper::GetTable(const std::string& name, uint32_t flags,
std::vector<TargetInfo>* table) {
- char buffer[4096];
- struct dm_ioctl* io = reinterpret_cast<struct dm_ioctl*>(buffer);
+ std::vector<char> buffer;
+ struct dm_ioctl* io = nullptr;
- InitIo(io, name);
- io->data_size = sizeof(buffer);
- io->data_start = sizeof(*io);
- io->flags = flags;
- if (ioctl(fd_, DM_TABLE_STATUS, io) < 0) {
- PLOG(ERROR) << "DM_TABLE_STATUS failed for " << name;
- return false;
- }
- if (io->flags & DM_BUFFER_FULL_FLAG) {
- PLOG(ERROR) << "DM_TABLE_STATUS result for " << name << " was too large";
- return false;
+ for (buffer.resize(4096);; buffer.resize(buffer.size() * 2)) {
+ io = reinterpret_cast<struct dm_ioctl*>(&buffer[0]);
+
+ InitIo(io, name);
+ io->data_size = buffer.size();
+ io->data_start = sizeof(*io);
+ io->flags = flags;
+ if (ioctl(fd_, DM_TABLE_STATUS, io) < 0) {
+ PLOG(ERROR) << "DM_TABLE_STATUS failed for " << name;
+ return false;
+ }
+ if (!(io->flags & DM_BUFFER_FULL_FLAG)) break;
}
uint32_t cursor = io->data_start;
- uint32_t data_end = std::min(io->data_size, uint32_t(sizeof(buffer)));
+ uint32_t data_end = std::min(io->data_size, uint32_t(buffer.size()));
for (uint32_t i = 0; i < io->target_count; i++) {
if (cursor + sizeof(struct dm_target_spec) > data_end) {
break;
@@ -324,14 +325,14 @@
// After each dm_target_spec is a status string. spec->next is an
// offset from |io->data_start|, and we clamp it to the size of our
// buffer.
- struct dm_target_spec* spec = reinterpret_cast<struct dm_target_spec*>(buffer + cursor);
+ struct dm_target_spec* spec = reinterpret_cast<struct dm_target_spec*>(&buffer[cursor]);
uint32_t data_offset = cursor + sizeof(dm_target_spec);
uint32_t next_cursor = std::min(io->data_start + spec->next, data_end);
std::string data;
if (next_cursor > data_offset) {
// Note: we use c_str() to eliminate any extra trailing 0s.
- data = std::string(buffer + data_offset, next_cursor - data_offset).c_str();
+ data = std::string(&buffer[data_offset], next_cursor - data_offset).c_str();
}
table->emplace_back(*spec, data);
cursor = next_cursor;
diff --git a/fs_mgr/tools/dmctl.cpp b/fs_mgr/tools/dmctl.cpp
index 3b6ff9b..63661f0 100644
--- a/fs_mgr/tools/dmctl.cpp
+++ b/fs_mgr/tools/dmctl.cpp
@@ -27,6 +27,7 @@
#include <android-base/unique_fd.h>
#include <libdm/dm.h>
+#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
@@ -50,6 +51,7 @@
static int Usage(void) {
std::cerr << "usage: dmctl <command> [command options]" << std::endl;
+ std::cerr << " dmctl -f file" << std::endl;
std::cerr << "commands:" << std::endl;
std::cerr << " create <dm-name> [-ro] <targets...>" << std::endl;
std::cerr << " delete <dm-name>" << std::endl;
@@ -58,6 +60,8 @@
std::cerr << " table <dm-name>" << std::endl;
std::cerr << " help" << std::endl;
std::cerr << std::endl;
+ std::cerr << "-f file reads command and all parameters from named file" << std::endl;
+ std::cerr << std::endl;
std::cerr << "Target syntax:" << std::endl;
std::cerr << " <target_type> <start_sector> <num_sectors> [target_data]" << std::endl;
return -EINVAL;
@@ -340,12 +344,40 @@
// clang-format on
};
+static bool ReadFile(const char* filename, std::vector<std::string>* args,
+ std::vector<char*>* arg_ptrs) {
+ std::ifstream file(filename);
+ if (!file) return false;
+
+ std::string arg;
+ while (file >> arg) args->push_back(arg);
+
+ for (auto const& i : *args) arg_ptrs->push_back(const_cast<char*>(i.c_str()));
+ return true;
+}
+
int main(int argc, char** argv) {
android::base::InitLogging(argv, &android::base::StderrLogger);
if (argc < 2) {
return Usage();
}
+ std::vector<std::string> args;
+ std::vector<char*> arg_ptrs;
+ if (std::string("-f") == argv[1]) {
+ if (argc != 3) {
+ return Usage();
+ }
+
+ args.push_back(argv[0]);
+ if (!ReadFile(argv[2], &args, &arg_ptrs)) {
+ return Usage();
+ }
+
+ argc = arg_ptrs.size();
+ argv = &arg_ptrs[0];
+ }
+
for (const auto& cmd : cmdmap) {
if (cmd.first == argv[1]) {
return cmd.second(argc - 2, argv + 2);