Merge changes from topic "sys_rootdisk" (4c7dc7bd) · Commits · e / os / android_system_core

init/README.md

+10 −5

Original line number	Diff line number	Diff line
		@@ -804,13 +804,18 @@ Init provides state information with the following properties.
		`init.svc.<name>`
		> State of a named service ("stopped", "stopping", "running", "restarting")

		`dev.mnt.blk.<mount_point>`
		`dev.mnt.dev.<mount_point>`, `dev.mnt.blk.<mount_point>`, `dev.mnt.rootdisk.<mount_point>`
		> Block device base name associated with a mount_point.
		The mount_point has / replaced by . and if referencing the root mount point
		"/", it will use "/root", specifically `dev.mnt.blk.root`.
		Meant for references to `/sys/device/block/${dev.mnt.blk.<mount_point>}/` and
		`/sys/fs/ext4/${dev.mnt.blk.<mount_point>}/` to tune the block device
		characteristics in a device agnostic manner.
		"/", it will use "/root".
		`dev.mnt.dev.<mount_point>` indicates a block device attached to filesystems.
		(e.g., dm-N or sdaN/mmcblk0pN to access `/sys/fs/ext4/${dev.mnt.dev.<mount_point>}/`)

		`dev.mnt.blk.<mount_point>` indicates the disk partition to the above block device.
		(e.g., sdaN / mmcblk0pN to access `/sys/class/block/${dev.mnt.blk.<mount_point>}/`)

		`dev.mnt.rootdisk.<mount_point>` indicates the root disk to contain the above disk partition.
		(e.g., sda / mmcblk0 to access `/sys/class/block/${dev.mnt.rootdisk.<mount_point>}/queue`)

		Init responds to properties that begin with `ctl.`. These properties take the format of
		`ctl.[<target>_]<command>` and the _value_ of the system property is used as a parameter. The

init/mount_handler.cpp

+65 −19

Original line number	Diff line number	Diff line
		@@ -25,6 +25,7 @@
		#include <unistd.h>

		#include <algorithm>
		#include <filesystem>
		#include <string>
		#include <utility>
		#include <vector>
		@@ -32,6 +33,7 @@
		#include <android-base/file.h>
		#include <android-base/logging.h>
		#include <android-base/properties.h>
		#include <android-base/stringprintf.h>
		#include <android-base/strings.h>
		#include <fs_mgr.h>
		#include <fstab/fstab.h>
		@@ -39,6 +41,9 @@

		#include "epoll.h"

		using android::base::Basename;
		using android::base::StringPrintf;

		namespace android {
		namespace init {

		@@ -67,41 +72,82 @@ MountHandlerEntry ParseMount(const std::string& line) {
		return MountHandlerEntry(fields[0], fields[1], fields[2]);
		}

		// return sda25 for dm-4, sda25 for sda25, or mmcblk0p24 for mmcblk0p24
		std::string GetDiskPart(std::string blockdev) {
		if (blockdev.find('/') != std::string::npos) return {};

		while (android::base::StartsWith(blockdev, "dm-")) {
		auto& dm = dm::DeviceMapper::Instance();
		std::optional<std::string> parent = dm.GetParentBlockDeviceByPath("/dev/block/" + blockdev);
		if (parent) {
		blockdev = android::base::Basename(*parent);
		} else {
		return {};
		}
		}
		return blockdev;
		}

		// return sda for sda25, or mmcblk0 for mmcblk0p24
		std::string GetRootDisk(std::string blockdev) {
		if (blockdev.empty()) return {};
		if (blockdev.find('/') != std::string::npos) return {};

		std::error_code ec;
		for (const auto& entry : std::filesystem::directory_iterator("/sys/block", ec)) {
		const std::string path = entry.path().string();
		if (std::filesystem::exists(StringPrintf("%s/%s", path.c_str(), blockdev.c_str()))) {
		return Basename(path);
		}
		}
		return {};
		}

		void SetMountProperty(const MountHandlerEntry& entry, bool add) {
		static constexpr char devblock[] = "/dev/block/";
		if (!android::base::StartsWith(entry.blk_device, devblock)) return;
		std::string value;
		auto target = entry.blk_device.substr(strlen(devblock));
		std::string diskpart, rootdisk;
		if (add) {
		value = entry.blk_device.substr(strlen(devblock));
		if (android::base::StartsWith(value, "sd")) {
		// All sd partitions inherit their queue characteristics
		// from the whole device reference. Strip partition number.
		auto it = std::find_if(value.begin(), value.end(), [](char c) { return isdigit(c); });
		if (it != value.end()) value.erase(it, value.end());
		}
		auto queue = "/sys/block/" + value + "/queue";
		diskpart = GetDiskPart(target);
		rootdisk = GetRootDisk(diskpart);

		struct stat sb;
		if (stat(queue.c_str(), &sb) \|\| !S_ISDIR(sb.st_mode)) value = "";
		if (stat(entry.mount_point.c_str(), &sb) \|\| !S_ISDIR(sb.st_mode)) value = "";
		if (stat(entry.mount_point.c_str(), &sb) \|\| !S_ISDIR(sb.st_mode)) rootdisk = "";
		// Clear the noise associated with loopback and APEX.
		if (android::base::StartsWith(value, "loop")) value = "";
		if (android::base::StartsWith(entry.mount_point, "/apex/")) value = "";
		if (android::base::StartsWith(target, "loop")) rootdisk = "";
		if (android::base::StartsWith(entry.mount_point, "/apex/")) rootdisk = "";
		}
		auto mount_prop = entry.mount_point;
		if (mount_prop == "/") mount_prop = "/root";
		std::replace(mount_prop.begin(), mount_prop.end(), '/', '.');
		auto blk_mount_prop = "dev.mnt.blk" + mount_prop;
		auto dev_mount_prop = "dev.mnt.dev" + mount_prop;
		// Set property even if its value does not change to trigger 'on property:'
		auto rootdisk_mount_prop = "dev.mnt.rootdisk" + mount_prop;
		// Set property even if its rootdisk does not change to trigger 'on property:'
		// handling, except for clearing non-existent or already clear property.
		// Goal is reduction of empty properties and associated triggers.
		if (value.empty() && android::base::GetProperty(blk_mount_prop, "").empty()) return;
		android::base::SetProperty(blk_mount_prop, value);
		if (!value.empty()) {
		android::base::SetProperty(dev_mount_prop, entry.blk_device.substr(strlen(devblock)));
		} else {
		if (rootdisk.empty() && android::base::GetProperty(blk_mount_prop, "").empty()) return;

		if (rootdisk.empty()) {
		android::base::SetProperty(blk_mount_prop, "");
		android::base::SetProperty(dev_mount_prop, "");
		}
		android::base::SetProperty(rootdisk_mount_prop, "");
		return;
		}

		// 1. dm-N
		// dev.mnt.dev.data = dm-N
		// dev.mnt.blk.data = sdaN or mmcblk0pN
		// dev.mnt.rootdisk.data = sda or mmcblk0
		//
		// 2. sdaN or mmcblk0pN
		// dev.mnt.dev.data = sdaN or mmcblk0pN
		// dev.mnt.blk.data = sdaN or mmcblk0pN
		// dev.mnt.rootdisk.data = sda or mmcblk0
		android::base::SetProperty(dev_mount_prop, target);
		android::base::SetProperty(blk_mount_prop, diskpart);
		android::base::SetProperty(rootdisk_mount_prop, rootdisk);
		}

		} // namespace

rootdir/init.rc

+6 −3

Original line number	Diff line number	Diff line
		@@ -1085,9 +1085,11 @@ on boot
		mkdir /dev/sys/fs/by-name 0755 system system
		symlink /sys/fs/f2fs/${dev.mnt.dev.data} /dev/sys/fs/by-name/userdata

		# to access dm-<num> sysfs
		# dev.mnt.dev.data=dm-N, dev.mnt.blk.data=sdaN/mmcblk0pN, dev.mnt.rootdisk.data=sda/mmcblk0, or
		# dev.mnt.dev.data=sdaN/mmcblk0pN, dev.mnt.blk.data=sdaN/mmcblk0pN, dev.mnt.rootdisk.data=sda/mmcblk0
		mkdir /dev/sys/block/by-name 0755 system system
		symlink /sys/devices/virtual/block/${dev.mnt.dev.data} /dev/sys/block/by-name/userdata
		symlink /sys/class/block/${dev.mnt.dev.data} /dev/sys/block/by-name/userdata
		symlink /sys/class/block/${dev.mnt.rootdisk.data} /dev/sys/block/by-name/rootdisk

		# F2FS tuning. Set cp_interval larger than dirty_expire_centisecs, 30 secs,
		# to avoid power consumption when system becomes mostly idle. Be careful
		@@ -1099,8 +1101,9 @@ on boot

		# limit discard size to 128MB in order to avoid long IO latency
		# for filesystem tuning first (dm or sda)
		# Note that, if dm-<num> is used, sda/mmcblk0 should be tuned in vendor/init.rc
		# this requires enabling selinux entry for sda/mmcblk0 in vendor side
		write /dev/sys/block/by-name/userdata/queue/discard_max_bytes 134217728
		write /dev/sys/block/by-name/rootdisk/queue/discard_max_bytes 134217728

		# Permissions for System Server and daemons.
		chown system system /sys/power/autosleep