// Copyright 2017 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Tests for MinFS-specific behavior.

#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <unistd.h>

#include <fbl/algorithm.h>
#include <fbl/unique_fd.h>
#include <fuchsia/io/c/fidl.h>
#include <fuchsia/minfs/c/fidl.h>
#include <fvm/fvm.h>
#include <lib/fdio/vfs.h>
#include <lib/fzl/fdio.h>
#include <minfs/format.h>
#include <unittest/unittest.h>
#include <zircon/device/vfs.h>

#include "filesystems.h"
#include "misc.h"

namespace {

bool QueryInfo(fuchsia_io_FilesystemInfo* info) {
    BEGIN_HELPER;
    fbl::unique_fd fd(open(kMountPath, O_RDONLY | O_DIRECTORY));
    ASSERT_TRUE(fd);
    zx_status_t status;
    fzl::FdioCaller caller(fbl::move(fd));
    ASSERT_EQ(fuchsia_io_DirectoryAdminQueryFilesystem(caller.borrow_channel(), &status, info),
              ZX_OK);
    ASSERT_EQ(status, ZX_OK);
    const char* kFsName = "minfs";
    const char* name = reinterpret_cast<const char*>(info->name);
    ASSERT_EQ(strncmp(name, kFsName, strlen(kFsName)), 0, "Unexpected filesystem mounted");
    ASSERT_EQ(info->block_size, minfs::kMinfsBlockSize);
    ASSERT_EQ(info->max_filename_size, minfs::kMinfsMaxNameSize);
    ASSERT_EQ(info->fs_type, VFS_TYPE_MINFS);
    ASSERT_NE(info->fs_id, 0);

    ASSERT_EQ(info->used_bytes % info->block_size, 0);
    ASSERT_EQ(info->total_bytes % info->block_size, 0);
    END_HELPER;
}

// A simple structure used to validate the results of QueryInfo.
struct ExpectedQueryInfo {
    size_t total_bytes;
    size_t used_bytes;
    size_t total_nodes;
    size_t used_nodes;
    size_t free_shared_pool_bytes;
};

bool VerifyQueryInfo(const ExpectedQueryInfo& expected) {
    BEGIN_HELPER;

    fuchsia_io_FilesystemInfo info;
    ASSERT_TRUE(QueryInfo(&info));
    ASSERT_EQ(info.total_bytes, expected.total_bytes);
    ASSERT_EQ(info.used_bytes, expected.used_bytes);
    ASSERT_EQ(info.total_nodes, expected.total_nodes);
    ASSERT_EQ(info.used_nodes, expected.used_nodes);
    ASSERT_EQ(info.free_shared_pool_bytes, expected.free_shared_pool_bytes);
    END_HELPER;
}

// Verify intial conditions on a filesystem, and validate that filesystem
// modifications adjust the query info accordingly.
bool TestQueryInfo() {
    BEGIN_TEST;

    // This test assumes it is running on a disk with the default slice size.
    const size_t kSliceSize = TEST_FVM_SLICE_SIZE_DEFAULT;
    const size_t kTotalDeviceSize = test_disk_info.block_count * test_disk_info.block_size;

    const size_t kTotalSlices = fvm::UsableSlicesCount(kTotalDeviceSize, kSliceSize);
    const size_t kFreeSlices = kTotalSlices - minfs::kMinfsMinimumSlices;

    ExpectedQueryInfo expected_info = {};
    expected_info.total_bytes = kSliceSize;
    // TODO(ZX-1372): Adjust this once minfs accounting on truncate is fixed.
    expected_info.used_bytes = 2 * minfs::kMinfsBlockSize;
    // The inode table's implementation is currently a flat array on disk.
    expected_info.total_nodes = kSliceSize / sizeof(minfs::minfs_inode_t);
    // The "zero-th" inode is reserved, as well as the root directory.
    expected_info.used_nodes = 2;
    // The remainder of the FVM should be unused during this filesystem test.
    expected_info.free_shared_pool_bytes = kFreeSlices * kSliceSize;
    ASSERT_TRUE(VerifyQueryInfo(expected_info));

    // Allocate kExtraNodeCount new files, each using truncated (sparse) files.
    const int kExtraNodeCount = 16;
    for (int i = 0; i < kExtraNodeCount; i++) {
        char path[128];
        snprintf(path, sizeof(path) - 1, "%s/file_%d", kMountPath, i);

        int fd = open(path, O_CREAT | O_RDWR);
        ASSERT_GT(fd, 0, "Failed to create file");
        ASSERT_EQ(ftruncate(fd, 30 * 1024), 0);
        ASSERT_EQ(close(fd), 0);
    }

    // Adjust our query expectations: We should see 16 new nodes, but no other
    // difference.
    expected_info.used_nodes += kExtraNodeCount;
    ASSERT_TRUE(VerifyQueryInfo(expected_info));
    END_TEST;
}

bool ToggleMetrics(bool enabled) {
    BEGIN_HELPER;
    fbl::unique_fd fd(open(kMountPath, O_RDONLY | O_DIRECTORY));
    ASSERT_TRUE(fd);
    fzl::FdioCaller caller(fbl::move(fd));
    zx_status_t status;
    ASSERT_EQ(fuchsia_minfs_MinfsToggleMetrics(caller.borrow_channel(), enabled, &status), ZX_OK);
    ASSERT_EQ(status, ZX_OK);
    END_HELPER;
}

bool GetMetricsUnavailable() {
    BEGIN_HELPER;
    fbl::unique_fd fd(open(kMountPath, O_RDONLY | O_DIRECTORY));
    ASSERT_TRUE(fd);
    zx_status_t status;
    fzl::FdioCaller caller(fbl::move(fd));
    fuchsia_minfs_Metrics metrics;
    ASSERT_EQ(fuchsia_minfs_MinfsGetMetrics(caller.borrow_channel(), &status, &metrics),
              ZX_OK);
    ASSERT_EQ(status, ZX_ERR_UNAVAILABLE);
    END_HELPER;
}

bool GetMetrics(fuchsia_minfs_Metrics* metrics) {
    BEGIN_HELPER;
    fbl::unique_fd fd(open(kMountPath, O_RDONLY | O_DIRECTORY));
    ASSERT_TRUE(fd);
    zx_status_t status;
    fzl::FdioCaller caller(fbl::move(fd));
    ASSERT_EQ(fuchsia_minfs_MinfsGetMetrics(caller.borrow_channel(), &status, metrics),
              ZX_OK);
    ASSERT_EQ(status, ZX_OK);
    END_HELPER;
}

// Validate that Minfs metrics are functioning correctly.
bool TestMetrics() {
    BEGIN_TEST;

    ASSERT_TRUE(GetMetricsUnavailable());
    ASSERT_TRUE(ToggleMetrics(true));

    fuchsia_minfs_Metrics metrics;
    ASSERT_TRUE(GetMetrics(&metrics));

    ASSERT_EQ(metrics.create_calls, 0);
    ASSERT_EQ(metrics.create_calls_success, 0);

    char path[128];
    snprintf(path, sizeof(path) - 1, "%s/test-file", kMountPath);
    fbl::unique_fd fd(open(path, O_CREAT | O_RDWR));
    ASSERT_TRUE(fd);
    ASSERT_TRUE(GetMetrics(&metrics));
    ASSERT_EQ(metrics.create_calls, 1);
    ASSERT_EQ(metrics.create_calls_success, 1);

    fd.reset(open(path, O_CREAT | O_RDWR | O_EXCL));
    ASSERT_FALSE(fd);
    ASSERT_TRUE(GetMetrics(&metrics));
    ASSERT_EQ(metrics.create_calls, 2);
    ASSERT_EQ(metrics.create_calls_success, 1);

    ASSERT_TRUE(ToggleMetrics(false));
    ASSERT_TRUE(GetMetricsUnavailable());

    END_TEST;
}

bool GetUsedBlocks(uint32_t* used_blocks) {
    BEGIN_HELPER;
    fuchsia_io_FilesystemInfo info;
    ASSERT_TRUE(QueryInfo(&info));
    *used_blocks = static_cast<uint32_t>((info.total_bytes - info.used_bytes) / info.block_size);
    END_HELPER;
}

// Write to the file until at most |max_remaining_blocks| remain in the partition.
// Return the new remaining block count as |actual_remaining_blocks|.
bool FillPartition(int fd, uint32_t max_remaining_blocks, uint32_t* actual_remaining_blocks) {
    BEGIN_HELPER;
    char data[minfs::kMinfsBlockSize];
    memset(data, 0xaa, sizeof(data));
    uint32_t free_blocks;

    while (true) {
        ASSERT_TRUE(GetUsedBlocks(&free_blocks));
        if (free_blocks <= max_remaining_blocks) {
            break;
        }

        ASSERT_EQ(write(fd, data, sizeof(data)), sizeof(data));
    }

    ASSERT_LE(free_blocks, max_remaining_blocks);
    ASSERT_GT(free_blocks, 0);

    *actual_remaining_blocks = free_blocks;
    END_HELPER;
}

// Return number of blocks allocated by the file at |fd|.
bool GetFileBlocks(int fd, uint64_t* blocks) {
    BEGIN_HELPER;
    struct stat stats;
    ASSERT_EQ(fstat(fd, &stats), 0);
    off_t size = stats.st_blocks * VNATTR_BLKSIZE;
    ASSERT_EQ(size % minfs::kMinfsBlockSize, 0);
    *blocks = static_cast<uint64_t>(size / minfs::kMinfsBlockSize);
    END_HELPER;
}

// Fill a directory to at most |max_blocks| full of direntries.
// We assume the directory is empty to begin with, and any files we are adding do not already exist.
bool FillDirectory(int dir_fd, uint32_t max_blocks) {
    BEGIN_HELPER;

    uint32_t file_count = 0;
    while (true) {
        char path[128];
        snprintf(path, sizeof(path) - 1, "file_%u", file_count++);
        fbl::unique_fd fd(openat(dir_fd, path, O_CREAT | O_RDWR));
        ASSERT_TRUE(fd);

        uint64_t current_blocks;
        ASSERT_TRUE(GetFileBlocks(dir_fd, &current_blocks));

        if (current_blocks > max_blocks) {
            ASSERT_EQ(unlinkat(dir_fd, path, 0), 0);
            break;
        }
    }

    END_HELPER;
}

// Test various operations when the Minfs partition is near capacity.
bool TestFullOperations() {
    BEGIN_TEST;

    // Define file names we will use upfront.
    const char* big_path = "big_file";
    const char* med_path = "med_file";
    const char* sml_path = "sml_file";

    // Open the mount point and create three files.
    fbl::unique_fd mnt_fd(open(kMountPath, O_RDONLY));
    ASSERT_TRUE(mnt_fd);

    fbl::unique_fd big_fd(openat(mnt_fd.get(), big_path, O_CREAT | O_RDWR));
    ASSERT_TRUE(big_fd);

    fbl::unique_fd med_fd(openat(mnt_fd.get(), med_path, O_CREAT | O_RDWR));
    ASSERT_TRUE(med_fd);

    fbl::unique_fd sml_fd(openat(mnt_fd.get(), sml_path, O_CREAT | O_RDWR));
    ASSERT_TRUE(sml_fd);

    // Write to the "big" file, filling the partition
    // and leaving at most kMinfsDirect + 1 blocks unused.
    uint32_t free_blocks = minfs::kMinfsDirect + 1;
    uint32_t actual_blocks;
    ASSERT_TRUE(FillPartition(big_fd.get(), free_blocks, &actual_blocks));

    // Write enough data to the second file to take up all remaining blocks except for 1.
    // This should strictly be writing to the direct block section of the file.
    char data[minfs::kMinfsBlockSize];
    memset(data, 0xaa, sizeof(data));
    for (unsigned i = 0; i < actual_blocks - 1; i++) {
        ASSERT_EQ(write(med_fd.get(), data, sizeof(data)), sizeof(data));
    }

    // Make sure we now have only 1 block remaining.
    ASSERT_TRUE(GetUsedBlocks(&free_blocks));
    ASSERT_EQ(free_blocks, 1);

    // We should now have exactly 1 free block remaining. Attempt to write into the indirect
    // section of the file so we ensure that at least 2 blocks are required.
    // This is expected to fail.
    ASSERT_EQ(lseek(med_fd.get(), minfs::kMinfsBlockSize * minfs::kMinfsDirect, SEEK_SET),
              minfs::kMinfsBlockSize * minfs::kMinfsDirect);
    ASSERT_LT(write(med_fd.get(), data, sizeof(data)), 0);

    // Since the last operation failed, we should still have 1 free block remaining. Writing to the
    // beginning of the second file should only require 1 (direct) block, and therefore pass.
    // Note: This fails without block reservation.
    ASSERT_EQ(write(sml_fd.get(), data, sizeof(data)), sizeof(data));

    // Without block reservation, something from the failed write remains allocated. Try editing
    // nearby blocks to force a writeback of partially allocated data.
    // Note: This will likely fail without block reservation.
    struct stat s;
    ASSERT_EQ(fstat(big_fd.get(), &s), 0);
    ssize_t truncate_size = fbl::round_up(static_cast<uint64_t>(s.st_size / 2),
                                          minfs::kMinfsBlockSize);
    ASSERT_EQ(ftruncate(big_fd.get(), truncate_size), 0);
    ASSERT_TRUE(check_remount());

    // Re-open files.
    mnt_fd.reset(open(kMountPath, O_RDONLY));
    ASSERT_TRUE(mnt_fd);
    big_fd.reset(openat(mnt_fd.get(), big_path, O_RDWR));
    ASSERT_TRUE(big_fd);
    sml_fd.reset(openat(mnt_fd.get(), sml_path, O_RDWR));
    ASSERT_TRUE(sml_fd);

    // Make sure we now have at least kMinfsDirect + 1 blocks remaining.
    ASSERT_TRUE(GetUsedBlocks(&free_blocks));
    ASSERT_GE(free_blocks, minfs::kMinfsDirect + 1);

    // We have some room now, so create a new directory.
    const char* dir_path = "directory";
    ASSERT_EQ(mkdirat(mnt_fd.get(), dir_path, 0666), 0);
    fbl::unique_fd dir_fd(openat(mnt_fd.get(), dir_path, O_RDONLY));
    ASSERT_TRUE(dir_fd);

    // Fill the directory up to kMinfsDirect blocks full of direntries.
    ASSERT_TRUE(FillDirectory(dir_fd.get(), minfs::kMinfsDirect));

    // Now re-fill the partition by writing as much as possible back to the original file.
    // Attempt to leave 1 block free.
    ASSERT_EQ(lseek(big_fd.get(), truncate_size, SEEK_SET), truncate_size);
    free_blocks = 1;
    ASSERT_TRUE(FillPartition(big_fd.get(), free_blocks, &actual_blocks));

    if (actual_blocks == 0) {
        // It is possible that, in our previous allocation of big_fd, we ended up leaving less than
        // |free_blocks| free. Since the file has grown potentially large, it is possible that
        // allocating a single block will also allocate additional indirect blocks.
        // For example, in a case where we have 2 free blocks remaining and expect to allocate 1,
        // we may actually end up allocating 2 instead, leaving us with 0 free blocks.
        // Since sml_fd is using less than kMinfsDirect blocks and thus is guaranteed to have a 1:1
        // block usage ratio, we can remedy this situation by removing a single block from sml_fd.
        ASSERT_EQ(ftruncate(sml_fd.get(), 0), 0);
    }

    while (actual_blocks > free_blocks) {
        // Otherwise, if too many blocks remain (if e.g. we needed to allocate 3 blocks but only 2
        // are remaining), write to sml_fd until only 1 remains.
        ASSERT_EQ(write(sml_fd.get(), data, sizeof(data)), sizeof(data));
        actual_blocks--;
    }

    // Ensure that there is now exactly one block remaining.
    ASSERT_TRUE(GetUsedBlocks(&actual_blocks));
    ASSERT_EQ(free_blocks, actual_blocks);

    // Now, attempt to add one more file to the directory we created. Since it will need to
    // allocate 2 blocks (1 indirect + 1 direct) and there is only 1 remaining, it should fail.
    uint64_t block_count;
    ASSERT_TRUE(GetFileBlocks(dir_fd.get(), &block_count));
    ASSERT_EQ(block_count, minfs::kMinfsDirect);
    fbl::unique_fd tmp_fd(openat(dir_fd.get(), "new_file", O_CREAT | O_RDWR));
    ASSERT_FALSE(tmp_fd);

    // Again, try editing nearby blocks to force bad allocation leftovers to be persisted, and
    // remount the partition. This is expected to fail without block reservation.
    ASSERT_EQ(fstat(big_fd.get(), &s), 0);
    ASSERT_EQ(s.st_size % minfs::kMinfsBlockSize, 0);
    truncate_size = s.st_size - minfs::kMinfsBlockSize;
    ASSERT_EQ(ftruncate(big_fd.get(), truncate_size), 0);
    ASSERT_TRUE(check_remount());

    // Re-open files.
    mnt_fd.reset(open(kMountPath, O_RDONLY));
    ASSERT_TRUE(mnt_fd);
    big_fd.reset(openat(mnt_fd.get(), big_path, O_RDWR));
    ASSERT_TRUE(big_fd);
    sml_fd.reset(openat(mnt_fd.get(), sml_path, O_RDWR));
    ASSERT_TRUE(sml_fd);

    // Fill the partition again, writing one block of data to sml_fd
    // in case we need an emergency truncate.
    ASSERT_EQ(write(sml_fd.get(), data, sizeof(data)), sizeof(data));
    ASSERT_EQ(lseek(big_fd.get(), truncate_size, SEEK_SET), truncate_size);
    free_blocks = 1;
    ASSERT_TRUE(FillPartition(big_fd.get(), free_blocks, &actual_blocks));

    if (actual_blocks == 0) {
        // If we ended up with fewer blocks than expected, truncate sml_fd to create more space.
        // (See note above for details.)
        ASSERT_EQ(ftruncate(sml_fd.get(), 0), 0);
    }

    while (actual_blocks > free_blocks) {
        // Otherwise, if too many blocks remain (if e.g. we needed to allocate 3 blocks but only 2
        // are remaining), write to sml_fd until only 1 remains.
        ASSERT_EQ(write(sml_fd.get(), data, sizeof(data)), sizeof(data));
        actual_blocks--;
    }

    // Ensure that there is now exactly one block remaining.
    ASSERT_TRUE(GetUsedBlocks(&actual_blocks));
    ASSERT_EQ(free_blocks, actual_blocks);

    // Now, attempt to rename one of our original files under the new directory.
    // This should also fail.
    ASSERT_NE(renameat(mnt_fd.get(), med_path, dir_fd.get(), med_path), 0);

    // Again, truncate the original file and attempt to remount.
    // Again, this should fail without block reservation.
    ASSERT_EQ(fstat(big_fd.get(), &s), 0);
    ASSERT_EQ(s.st_size % minfs::kMinfsBlockSize, 0);
    truncate_size = s.st_size - minfs::kMinfsBlockSize;
    ASSERT_EQ(ftruncate(big_fd.get(), truncate_size), 0);
    ASSERT_TRUE(check_remount());
    END_TEST;
}

}  // namespace

#define RUN_MINFS_TESTS_NORMAL(name, CASE_TESTS) \
    FS_TEST_CASE(name, default_test_disk, CASE_TESTS, FS_TEST_NORMAL, minfs, 1)

#define RUN_MINFS_TESTS_FVM(name, CASE_TESTS) \
    FS_TEST_CASE(name##_fvm, default_test_disk, CASE_TESTS, FS_TEST_FVM, minfs, 1)

RUN_MINFS_TESTS_NORMAL(FsMinfsTests,
    RUN_TEST_LARGE(TestFullOperations)
)

RUN_MINFS_TESTS_FVM(FsMinfsFvmTests,
    RUN_TEST_MEDIUM(TestQueryInfo)
    RUN_TEST_MEDIUM(TestMetrics)
)