Merge "fs_mgr: check available space before creating zram backing device" into main

#include <sys/ioctl.h>

#include <sys/mount.h>

#include <sys/stat.h>

#include <sys/statvfs.h>

#include <sys/swap.h>

#include <sys/types.h>

#include <sys/utsname.h>

    return true;

}

/*

 * Zram backing device can be created as long as /data has at least `size`

 * free space, though we may want to leave some extra space for the remaining

 * boot process and other system activities.

 */

static bool ZramBackingDeviceSizeAvailable(off64_t size) {

    constexpr const char* data_path = "/data";

    uint64_t min_free_mb =

            android::base::GetUintProperty<uint64_t>("ro.zram_backing_device_min_free_mb", 0);

    // No min_free property. Skip the available size check.

    if (min_free_mb == 0) return true;

    struct statvfs vst;

    if (statvfs(data_path, &vst) < 0) {

        PERROR << "Cannot check available space: " << data_path;

        return false;

    }

    uint64_t size_free = static_cast<uint64_t>(vst.f_bfree) * vst.f_frsize;

    uint64_t size_required = size + (min_free_mb * 1024 * 1024);

    if (size_required > size_free) {

        PERROR << "Free space is not enough for zram backing device: " << size_required << " > "

               << size_free;

        return false;

    }

    return true;

}

static bool PrepareZramBackingDevice(off64_t size) {

    constexpr const char* file_path = "/data/per_boot/zram_swap";

    if (size == 0) return true;

    // Check available space

    if (!ZramBackingDeviceSizeAvailable(size)) {

        PERROR << "No space for target path: " << file_path;

        return false;

    }

    // Prepare target path

    unique_fd target_fd(TEMP_FAILURE_RETRY(open(file_path, O_RDWR | O_CREAT | O_CLOEXEC, 0600)));

    if (target_fd.get() == -1) {

    }

    if (fallocate(target_fd.get(), 0, 0, size) < 0) {

        PERROR << "Cannot truncate target path: " << file_path;

        unlink(file_path);

        return false;

    }