fs_mgr_get_mounted_entry_for_userdata: handle logical partitions
In case of GSI on DSU, /data is mounted on the following stack:
userdata -> userdata_gsi -> actual block device, and fstab returned from
ReadDefaultFstab() function will say that /data should be
mounted onto userdata_gsi. This configuration wasn't supported.
To support it, fs_mgr_get_mounted_entry_for_userdata now unwinds the
dm-device stack /data is mounted onto, and for each entry in fstab
resolves corresponding block device (in case of logical partitions by
asking DeviceMapper to resolve name -> path, and for other cases by
reading a symlink), and then checking whenever resolved block device
belongs to the unwinded stack.
Test: on both normal boot & DSU
Test: atest CtsUserspaceRebootHostSideTestCases
Test: atest CtsFsMgrTestCases
Bug: 148612148
Change-Id: I1bb3e64ae92d56de905b4f7f1997b7499b101b0f
diff --git a/fs_mgr/fs_mgr.cpp b/fs_mgr/fs_mgr.cpp
index 2e46b4f..d509e71 100644
--- a/fs_mgr/fs_mgr.cpp
+++ b/fs_mgr/fs_mgr.cpp
@@ -1589,76 +1589,58 @@
}
}
-static std::string ResolveBlockDevice(const std::string& block_device) {
+static bool UnwindDmDeviceStack(const std::string& block_device,
+ std::vector<std::string>* dm_stack) {
if (!StartsWith(block_device, "/dev/block/")) {
LWARNING << block_device << " is not a block device";
- return block_device;
+ return false;
}
- std::string name = block_device.substr(5);
- if (!StartsWith(name, "block/dm-")) {
- // Not a dm-device, but might be a symlink. Optimistically try to readlink.
- std::string result;
- if (Readlink(block_device, &result)) {
- return result;
- } else if (errno == EINVAL) {
- // After all, it wasn't a symlink.
- return block_device;
- } else {
- LERROR << "Failed to readlink " << block_device;
- return "";
- }
- }
- // It's a dm-device, let's find what's inside!
- std::string sys_dir = "/sys/" + name;
+ std::string current = block_device;
+ DeviceMapper& dm = DeviceMapper::Instance();
while (true) {
- std::string slaves_dir = sys_dir + "/slaves";
- std::unique_ptr<DIR, decltype(&closedir)> dir(opendir(slaves_dir.c_str()), closedir);
- if (!dir) {
- LERROR << "Failed to open " << slaves_dir;
- return "";
+ dm_stack->push_back(current);
+ if (!dm.IsDmBlockDevice(current)) {
+ break;
}
- std::string sub_device_name = "";
- for (auto entry = readdir(dir.get()); entry; entry = readdir(dir.get())) {
- if (entry->d_type != DT_LNK) continue;
- if (!sub_device_name.empty()) {
- LERROR << "Too many slaves in " << slaves_dir;
- return "";
- }
- sub_device_name = entry->d_name;
+ auto parent = dm.GetParentBlockDeviceByPath(current);
+ if (!parent) {
+ return false;
}
- if (sub_device_name.empty()) {
- LERROR << "No slaves in " << slaves_dir;
- return "";
- }
- if (!StartsWith(sub_device_name, "dm-")) {
- // Not a dm-device! We can stop now.
- return "/dev/block/" + sub_device_name;
- }
- // Still a dm-device, keep digging.
- sys_dir = "/sys/block/" + sub_device_name;
+ current = *parent;
}
+ return true;
}
FstabEntry* fs_mgr_get_mounted_entry_for_userdata(Fstab* fstab, const FstabEntry& mounted_entry) {
- std::string resolved_block_device = ResolveBlockDevice(mounted_entry.blk_device);
- if (resolved_block_device.empty()) {
+ if (mounted_entry.mount_point != "/data") {
+ LERROR << mounted_entry.mount_point << " is not /data";
return nullptr;
}
- LINFO << "/data is mounted on " << resolved_block_device;
+ std::vector<std::string> dm_stack;
+ if (!UnwindDmDeviceStack(mounted_entry.blk_device, &dm_stack)) {
+ LERROR << "Failed to unwind dm-device stack for " << mounted_entry.blk_device;
+ return nullptr;
+ }
for (auto& entry : *fstab) {
if (entry.mount_point != "/data") {
continue;
}
std::string block_device;
- if (!Readlink(entry.blk_device, &block_device)) {
- LWARNING << "Failed to readlink " << entry.blk_device;
+ if (entry.fs_mgr_flags.logical) {
+ if (!fs_mgr_update_logical_partition(&entry)) {
+ LERROR << "Failed to update logic partition " << entry.blk_device;
+ continue;
+ }
+ block_device = entry.blk_device;
+ } else if (!Readlink(entry.blk_device, &block_device)) {
+ PWARNING << "Failed to read link " << entry.blk_device;
block_device = entry.blk_device;
}
- if (block_device == resolved_block_device) {
+ if (std::find(dm_stack.begin(), dm_stack.end(), block_device) != dm_stack.end()) {
return &entry;
}
}
- LERROR << "Didn't find entry that was used to mount /data";
+ LERROR << "Didn't find entry that was used to mount /data onto " << mounted_entry.blk_device;
return nullptr;
}