Merge "libdm: Implement LoadTableAndActivate."

fs_mgr/libdm/dm.cpp

@@ -94,8 +94,37 @@ DmDeviceState DeviceMapper::state(const std::string& /* name */) const {
     return DmDeviceState::INVALID;
 }
 
-bool DeviceMapper::LoadTableAndActivate(const std::string& /* name */, const DmTable& /* table */) {
-    return false;
+bool DeviceMapper::CreateDevice(const std::string& name, const DmTable& table) {
+    if (!CreateDevice(name)) {
+        return false;
+    }
+    if (!LoadTableAndActivate(name, table)) {
+        DeleteDevice(name);
+        return false;
+    }
+    return true;
+}
+
+bool DeviceMapper::LoadTableAndActivate(const std::string& name, const DmTable& table) {
+    std::string ioctl_buffer(sizeof(struct dm_ioctl), 0);
+    ioctl_buffer += table.Serialize();
+
+    struct dm_ioctl* io = reinterpret_cast<struct dm_ioctl*>(&ioctl_buffer[0]);
+    InitIo(io, name);
+    io->data_size = ioctl_buffer.size();
+    io->data_start = sizeof(struct dm_ioctl);
+    io->target_count = static_cast<uint32_t>(table.num_targets());
+    if (ioctl(fd_, DM_TABLE_LOAD, io)) {
+        PLOG(ERROR) << "DM_TABLE_LOAD failed";
+        return false;
+    }
+
+    InitIo(io, name);
+    if (ioctl(fd_, DM_DEV_SUSPEND, io)) {
+        PLOG(ERROR) << "DM_TABLE_SUSPEND resume failed";
+        return false;
+    }
+    return true;
 }
 
 // Reads all the available device mapper targets and their corresponding

fs_mgr/libdm/dm_table.cpp

@@ -34,8 +34,8 @@ bool DmTable::valid() const {
     return true;
 }
 
-uint64_t DmTable::size() const {
-    return valid() ? size_ : 0;
+uint64_t DmTable::num_sectors() const {
+    return valid() ? num_sectors_ : 0;
 }
 
 // Returns a string represnetation of the table that is ready to be passed

fs_mgr/libdm/include/libdm/dm.h

@@ -69,14 +69,6 @@ class DeviceMapper final {
         uint64_t dev_;
     };
 
-    // Creates a device mapper device with given name.
-    // Return 'true' on success and 'false' on failure to
-    // create OR if a device mapper device with the same name already
-    // exists.
-    // TODO(b/110035986): Make this method private and to be only
-    // called through LoadTableAndActivate() below.
-    bool CreateDevice(const std::string& name);
-
     // Removes a device mapper device with the given name.
     // Returns 'true' on success, false otherwise.
     bool DeleteDevice(const std::string& name);
@@ -90,9 +82,14 @@ class DeviceMapper final {
     // One of INVALID, SUSPENDED or ACTIVE.
     DmDeviceState state(const std::string& name) const;
 
-    // Loads the device mapper table from parameter into the underlying
-    // device mapper device with given name and activate / resumes the device in the process.
-    // If a device mapper device with the 'name', doesn't exist, it will be created.
+    // Creates a device, loads the given table, and activates it. If the device
+    // is not able to be activated, it is destroyed, and false is returned.
+    bool CreateDevice(const std::string& name, const DmTable& table);
+
+    // Loads the device mapper table from parameter into the underlying device
+    // mapper device with given name and activate / resumes the device in the
+    // process. A device with the given name must already exist.
+    //
     // Returns 'true' on success, false otherwise.
     bool LoadTableAndActivate(const std::string& name, const DmTable& table);
 
@@ -140,6 +137,12 @@ class DeviceMapper final {
         }
     }
 
+    // Creates a device mapper device with given name.
+    // Return 'true' on success and 'false' on failure to
+    // create OR if a device mapper device with the same name already
+    // exists.
+    bool CreateDevice(const std::string& name);
+
     int fd_;
     // Non-copyable & Non-movable
     DeviceMapper(const DeviceMapper&) = delete;

fs_mgr/libdm/include/libdm/dm_table.h

@@ -30,7 +30,7 @@ namespace dm {
 
 class DmTable {
   public:
-    DmTable() : size_(0){};
+    DmTable() : num_sectors_(0){};
 
     // Adds a target to the device mapper table for a range specified in the target object.
     // The function will return 'true' if the target was successfully added and doesn't overlap with
@@ -48,9 +48,12 @@ class DmTable {
     // table is malformed.
     bool valid() const;
 
+    // Returns the toatl number of targets.
+    size_t num_targets() const { return targets_.size(); }
+
     // Returns the total size represented by the table in terms of number of 512-byte sectors.
     // NOTE: This function will overlook if there are any gaps in the targets added in the table.
-    uint64_t size() const;
+    uint64_t num_sectors() const;
 
     // Returns the string represntation of the table that is ready to be passed into the kernel
     // as part of the DM_TABLE_LOAD ioctl.
@@ -66,7 +69,7 @@ class DmTable {
 
     // Total size in terms of # of sectors, as calculated by looking at the last and the first
     // target in 'target_'.
-    uint64_t size_;
+    uint64_t num_sectors_;
 };
 
 }  // namespace dm

fs_mgr/tools/dmctl.cpp

@@ -34,6 +34,7 @@
 #include <vector>
 
 using DeviceMapper = ::android::dm::DeviceMapper;
+using DmTable = ::android::dm::DmTable;
 using DmTarget = ::android::dm::DmTarget;
 using DmBlockDevice = ::android::dm::DeviceMapper::DmBlockDevice;
 
@@ -53,9 +54,11 @@ static int DmCreateCmdHandler(int argc, char** argv) {
         return -EINVAL;
     }
 
+    DmTable table;
+
     std::string name = argv[0];
     DeviceMapper& dm = DeviceMapper::Instance();
-    if (!dm.CreateDevice(name)) {
+    if (!dm.CreateDevice(name, table)) {
         std::cerr << "Failed to create device-mapper device with name: " << name << std::endl;
         return -EIO;
     }