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Commit cc642ec7 authored by Treehugger Robot's avatar Treehugger Robot Committed by Gerrit Code Review
Browse files

Merge "Move GetMountedEntryForUserdata to fs_mgr.h"

parents 89744420 30b0c01d

fs_mgr/fs_mgr.cpp

+78 −7
Original line number Diff line number Diff line
@@ -96,6 +96,7 @@ 


using android::base::Basename;

using android::base::GetBoolProperty;

using android::base::Readlink;

using android::base::Realpath;

using android::base::SetProperty;

using android::base::StartsWith;
@@ -1587,6 +1588,79 @@ static bool fs_mgr_unmount_all_data_mounts(const std::string& block_device) { 
    }

}



static std::string ResolveBlockDevice(const std::string& block_device) {

    if (!StartsWith(block_device, "/dev/block/")) {

        LWARNING << block_device << " is not a block device";

        return block_device;

    }

    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;

    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 "";

        }

        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;

        }

        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;

    }

}



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()) {

        return nullptr;

    }

    LINFO << "/data is mounted on " << resolved_block_device;

    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;

            block_device = entry.blk_device;

        }

        if (block_device == resolved_block_device) {

            return &entry;

        }

    }

    LERROR << "Didn't find entry that was used to mount /data";

    return nullptr;

}



// TODO(b/143970043): return different error codes based on which step failed.

int fs_mgr_remount_userdata_into_checkpointing(Fstab* fstab) {

    Fstab proc_mounts;
@@ -1595,16 +1669,13 @@ int fs_mgr_remount_userdata_into_checkpointing(Fstab* fstab) { 
        return -1;

    }

    std::string block_device;

    if (auto entry = GetEntryForMountPoint(&proc_mounts, "/data"); entry != nullptr) {

        // Note: we don't care about a userdata wrapper here, since it's safe

        // to remount on top of the bow device instead, there will be no

        // conflicts.

        block_device = entry->blk_device;

    } else {

    auto mounted_entry = GetEntryForMountPoint(&proc_mounts, "/data");

    if (mounted_entry == nullptr) {

        LERROR << "/data is not mounted";

        return -1;

    }

    auto fstab_entry = GetMountedEntryForUserdata(fstab);

    block_device = mounted_entry->blk_device;

    auto fstab_entry = fs_mgr_get_mounted_entry_for_userdata(fstab, *mounted_entry);

    if (fstab_entry == nullptr) {

        LERROR << "Can't find /data in fstab";

        return -1;

fs_mgr/fs_mgr_fstab.cpp

+0 −83
Original line number Diff line number Diff line
@@ -819,89 +819,6 @@ std::vector<FstabEntry*> GetEntriesForMountPoint(Fstab* fstab, const std::string 
    return entries;

}



static std::string ResolveBlockDevice(const std::string& block_device) {

    if (!StartsWith(block_device, "/dev/block/")) {

        LWARNING << block_device << " is not a block device";

        return block_device;

    }

    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;

    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 "";

        }

        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;

        }

        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;

    }

}



FstabEntry* GetMountedEntryForUserdata(Fstab* fstab) {

    Fstab mounts;

    if (!ReadFstabFromFile("/proc/mounts", &mounts)) {

        LERROR << "Failed to read /proc/mounts";

        return nullptr;

    }

    auto mounted_entry = GetEntryForMountPoint(&mounts, "/data");

    if (mounted_entry == nullptr) {

        LWARNING << "/data is not mounted";

        return nullptr;

    }

    std::string resolved_block_device = ResolveBlockDevice(mounted_entry->blk_device);

    if (resolved_block_device.empty()) {

        return nullptr;

    }

    LINFO << "/data is mounted on " << resolved_block_device;

    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;

            block_device = entry.blk_device;

        }

        if (block_device == resolved_block_device) {

            return &entry;

        }

    }

    LERROR << "Didn't find entry that was used to mount /data";

    return nullptr;

}



std::set<std::string> GetBootDevices() {

    // First check the kernel commandline, then try the device tree otherwise

    std::string dt_file_name = get_android_dt_dir() + "/boot_devices";

fs_mgr/include/fs_mgr.h

+4 −0
Original line number Diff line number Diff line
@@ -107,6 +107,10 @@ enum FsMgrUmountStatus : int { 
// it destroys verity devices from device mapper after the device is unmounted.

int fs_mgr_umount_all(android::fs_mgr::Fstab* fstab);



// Finds a entry in |fstab| that was used to mount a /data |mounted_entry| from

// /proc/mounts.

android::fs_mgr::FstabEntry* fs_mgr_get_mounted_entry_for_userdata(

        android::fs_mgr::Fstab* fstab, const android::fs_mgr::FstabEntry& mounted_entry);

int fs_mgr_remount_userdata_into_checkpointing(android::fs_mgr::Fstab* fstab);



// Finds the dm_bow device on which this block device is stacked, or returns

fs_mgr/include_fstab/fstab/fstab.h

+0 −1
Original line number Diff line number Diff line
@@ -104,7 +104,6 @@ bool SkipMountingPartitions(Fstab* fstab); 
FstabEntry* GetEntryForMountPoint(Fstab* fstab, const std::string& path);

// The Fstab can contain multiple entries for the same mount point with different configurations.

std::vector<FstabEntry*> GetEntriesForMountPoint(Fstab* fstab, const std::string& path);

FstabEntry* GetMountedEntryForUserdata(Fstab* fstab);



// This method builds DSU fstab entries and transfer the fstab.

//

fs_mgr/tests/fs_mgr_test.cpp

+6 −1
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ 
#include <android-base/file.h>

#include <android-base/properties.h>

#include <android-base/strings.h>

#include <fs_mgr.h>

#include <fstab/fstab.h>

#include <gtest/gtest.h>
@@ -1015,6 +1016,10 @@ TEST(fs_mgr, UserdataMountedFromDefaultFstab) { 
    }

    Fstab fstab;

    ASSERT_TRUE(ReadDefaultFstab(&fstab)) << "Failed to read default fstab";

    ASSERT_NE(nullptr, GetMountedEntryForUserdata(&fstab))

    Fstab proc_mounts;

    ASSERT_TRUE(ReadFstabFromFile("/proc/mounts", &proc_mounts)) << "Failed to read /proc/mounts";

    auto mounted_entry = GetEntryForMountPoint(&proc_mounts, "/data");

    ASSERT_NE(mounted_entry, nullptr) << "/data is not mounted";

    ASSERT_NE(nullptr, fs_mgr_get_mounted_entry_for_userdata(&fstab, *mounted_entry))

            << "/data wasn't mounted from default fstab";

}