[feat.] a new tool 'overlaybd-merge'

overlaybd-merge can compact an overlaybd image with multiple layers
into a single layer.

Signed-off-by: Yifan Yuan <tuji.yyf@alibaba-inc.com>

src/image_file.cpp

@@ -28,6 +28,7 @@
 #include <photon/fs/aligned-file.h>
 #include <photon/fs/localfs.h>
 #include "overlaybd/lsmt/file.h"
+#include "overlaybd/lsmt/index.h"
 #include "overlaybd/zfile/zfile.h"
 #include "config.h"
 #include "image_file.h"
@@ -515,6 +516,12 @@ int ImageFile::init_image_file() {
     return -1;
 }
 
+int ImageFile::compact(IFile *as) {
+    return ((LSMT::IFileRO*)m_file)->flatten(as);
+}
+
+
+
 void ImageFile::set_auth_failed() {
     if (m_status == 0) // only set exit in image boot phase
     {

src/image_file.h

@@ -109,6 +109,8 @@ class ImageFile : public photon::fs::ForwardFile {
         return m_file;
     }
 
+    int compact(IFile *as);
+
 private:
     Prefetcher *m_prefetcher = nullptr;
     ImageConfigNS::ImageConfig conf;
@@ -126,5 +128,7 @@ class ImageFile : public photon::fs::ForwardFile {
     IFile *__open_ro_target_file(const std::string &);
     IFile *__open_ro_remote(const std::string &dir, const std::string &, const uint64_t, int);
     IFile *__open_ro_target_remote(const std::string &dir, const std::string &, const uint64_t, int);
+
+    // size_t seek_data(off_t begin, off_t end);
     void start_bk_dl_thread();
 };

src/image_service.h

@@ -58,6 +58,7 @@ class ImageService {
     // bool enable_acceleration(GlobalFs *global_fs, ImageConfigNS::P2PConfig conf);
     bool enable_acceleration();
 
+
     ImageConfigNS::GlobalConfig global_conf;
     struct GlobalFs global_fs;
     std::unique_ptr<OverlayBDMetric> metrics;

src/overlaybd/lsmt/file.cpp

@@ -177,6 +177,7 @@ struct HeaderTrailer {
 } __attribute__((packed));
 
 class LSMTReadOnlyFile;
+static int merge_files_ro(vector<IFile *> files, const CommitArgs &args);
 static LSMTReadOnlyFile *open_file_ro(IFile *file, bool ownership, bool reserve_tag);
 static HeaderTrailer *verify_ht(IFile *file, char *buf, bool is_trailer = false,
                                 ssize_t st_size = -1);
@@ -642,6 +643,33 @@ class LSMTReadOnlyFile : public IFileRW {
         ret.valid_data_size = size;
         return ret;
     }
+
+    virtual ssize_t seek_data(off_t begin, off_t end, vector<Segment> &segs) override {
+
+        begin /= ALIGNMENT;
+        end /= ALIGNMENT;
+        while (begin < end) {
+            SegmentMapping mappings[128];
+            auto length = (end - begin < Segment::MAX_LENGTH ? end - begin : Segment::MAX_LENGTH);
+            Segment s{(uint64_t)begin, (uint32_t)length};
+            auto find = m_index->lookup(s, mappings, 128);
+            if (find == 0) {
+                begin+=length;
+                continue;
+            }
+            segs.insert(segs.end(), mappings, mappings + find);
+            begin=mappings[find-1].end();
+
+        }
+        return segs.size();
+    }
+
+    virtual int flatten(IFile *as) override{
+        CommitArgs args(as);
+        vector<IFile*> files = m_files;
+        reverse(files.begin(), files.end());
+        return merge_files_ro(files, args);
+    }
 };
 
 class LSMTFile : public LSMTReadOnlyFile {
@@ -956,6 +984,15 @@ class LSMTFile : public LSMTReadOnlyFile {
                   data_stat.valid_data_size);
         return data_stat;
     }
+
+    virtual int flatten(IFile *as) override {
+
+        unique_ptr<IComboIndex> pmi((IComboIndex*)(m_index->make_read_only_index()));
+        CommitArgs args(as);
+        atomic_uint64_t _no_use_var(0);
+        CompactOptions opts(&m_files, (SegmentMapping*)(pmi->buffer()), pmi->size(), m_vsize, &args);
+        return compact(opts, _no_use_var);
+    }
 };
 class LSMTSparseFile : public LSMTFile {
 public:
@@ -1677,7 +1714,7 @@ IFileRO *open_files_ro(IFile **files, size_t n, bool ownership) {
     return rst;
 }
 
-int merge_files_ro(vector<IFile *> files, const CommitArgs &args) {
+static int merge_files_ro(vector<IFile *> files, const CommitArgs &args) {
     uint64_t vsize;
     vector<UUID> files_uuid(files.size());
     auto pmi = unique_ptr<IMemoryIndex>(load_merge_index(files, files_uuid, vsize));

src/overlaybd/lsmt/file.h

@@ -50,6 +50,11 @@ class IFileRO : public photon::fs::VirtualReadOnlyFile {
     virtual int get_uuid(UUID &out, size_t layer_idx = 0) const = 0;
 
     virtual std::vector<IFile *> get_lower_files() const = 0;
+
+    virtual ssize_t seek_data(off_t begin, off_t end, std::vector<Segment> &segs) = 0;
+
+    virtual int flatten(IFile *as) = 0;
+
 };
 
 struct CommitArgs {
@@ -96,6 +101,7 @@ class IFileRW : public IFileRO {
         uint64_t valid_data_size = -1; // size of valid data (excluding garbage)
     };
     virtual DataStat data_stat() const = 0;
+
 };
 
 // create a new writable LSMT file constitued by a data file and an index file,

src/overlaybd/lsmt/index.cpp

@@ -153,6 +153,8 @@ class Index : public IMemoryIndex {
     uint64_t vsize() const override {
         return virtual_size;
     }
+
+    UNIMPLEMENTED_POINTER(IMemoryIndex  *make_read_only_index() const override);
 };
 
 class LevelIndex : public Index {
@@ -254,6 +256,8 @@ class Index0 : public IComboIndex {
         }
     } alloc_blk;
 
+    // Index0(const set<SegmentMapping> &mapping) : mapping(mapping){};
+
     Index0(const SegmentMapping *pmappings = nullptr, size_t n = 0) {
         if (pmappings == nullptr)
             return;
@@ -505,6 +509,21 @@ class ComboIndex : public Index0 {
         merge_indexes(0, mappings, indexes, 2, 0, UINT64_MAX, false, max_level);
         return new Index(std::move(mappings));
     }
+
+     virtual Index *make_read_only_index() const override{
+        vector<SegmentMapping> mappings;
+        auto ro_idx0 = new Index;
+        ro_idx0->ownership = false;
+        ro_idx0->assign(mapping.begin(), mapping.end());
+        if (m_backing_index == nullptr) {
+            return ro_idx0;
+        }
+        const Index *indexes[2] = {ro_idx0, const_cast<Index *>(m_backing_index)};
+        merge_indexes(0, mappings, indexes, 2, 0, UINT64_MAX, false, 2);
+        delete ro_idx0;
+        return new Index(std::move(mappings));
+    }
+
 };
 
 //======================== END OF ComboIndex =============================//

src/overlaybd/lsmt/index.h

@@ -128,6 +128,8 @@ class IMemoryIndex {
     virtual uint64_t block_count() const = 0;
 
     virtual uint64_t vsize() const = 0;
+
+    virtual IMemoryIndex *make_read_only_index() const = 0;
 };
 
 // the level 0 memory index, which supports write
@@ -139,7 +141,7 @@ class IMemoryIndex0 : public IMemoryIndex {
     // dump the the whole index as an array
     // memory allocation is aligned to the `alignment`
     virtual SegmentMapping *dump(size_t alignment = 0) const = 0;
-    virtual IMemoryIndex *make_read_only_index() const = 0;
+    // virtual IMemoryIndex *make_read_only_index() const = 0;
 };
 
 class IComboIndex : public IMemoryIndex0 {
@@ -153,6 +155,8 @@ class IComboIndex : public IMemoryIndex0 {
     // and then clear the original index0.
     // virtual IMemoryIndex0* gc_index() = 0;
     virtual IMemoryIndex *load_range_index(int, int) const = 0;
+
+
 };
 
 // create writable level 0 memory index from an array of mappings;

src/overlaybd/lsmt/test/test.cpp

@@ -584,26 +584,70 @@ TEST_F(FileTest3, stack_files) {
     cout << "merging RO layers as " << fn_merged << endl;
     auto merged = lfs->open(fn_merged, O_RDWR | O_CREAT | O_TRUNC, S_IRWXU);
     merge_files_ro(files, FLAGS_layers, merged);
-    /*auto mergedro =*/::open_file_ro(merged, true);
+    auto mergedro =::open_file_ro(merged, true);
     cout << "verifying merged RO layers file" << endl;
+    verify_file(mergedro);
+    delete mergedro;
     cout << "verifying stacked RO layers file" << endl;
     auto lower = open_files_ro(files, FLAGS_layers);
     verify_file(lower);
     ((LSMTReadOnlyFile *)lower)->m_index =
         create_level_index(lower->index()->buffer(), lower->index()->size(), 0, UINT64_MAX, false);
     EXPECT_EQ(((LSMTReadOnlyFile *)lower)->close_seal(), -1);
     CommitArgs _(nullptr);
-    EXPECT_EQ(((LSMTReadOnlyFile *)lower)->commit(_), -1);
     auto stat = ((LSMTReadOnlyFile *)lower)->data_stat();
     LOG_INFO("RO valid data: `", stat.valid_data_size);
+    merged = lfs->open(fn_merged, O_RDWR | O_CREAT | O_TRUNC, S_IRWXU);
+    EXPECT_EQ(lower->flatten(merged), 0);
+    cout << "verifying flattened layer of lowers" << endl;
+    verify_file(fn_merged);
+    delete merged;
+    cout << "generating a RW layer by randwrite()" << endl;
+    auto upper = create_file_rw();
+    auto file = stack_files(upper, lower, 0, true);
+    randwrite(file, FLAGS_nwrites);
+    verify_file(file);
+    cout << "verifying flattened layer of stacked layers" << endl;
+
+    merged = lfs->open(fn_merged, O_RDWR | O_CREAT | O_TRUNC, S_IRWXU);
+    file->flatten(merged);
+    verify_file(fn_merged);
+    delete file;
+}
+
+TEST_F(FileTest3, seek_data) {
+    CleanUp();
+    cout << "generating " << FLAGS_layers << " RO layers by randwrite()" << endl;
+    for (int i = 0; i < FLAGS_layers; ++i) {
+        files[i] = create_commit_layer(0, ut_io_engine);
+    }
+
+    auto lower = open_files_ro(files, FLAGS_layers);
+    verify_file(lower);
+    ((LSMTReadOnlyFile *)lower)->m_index =
+        create_level_index(lower->index()->buffer(), lower->index()->size(), 0, UINT64_MAX, false);
     cout << "generating a RW layer by randwrite()" << endl;
     auto upper = create_file_rw();
     auto file = stack_files(upper, lower, 0, true);
     randwrite(file, FLAGS_nwrites);
     verify_file(file);
+
+    auto fmerged = create_file_rw();
+    vector<Segment> segs;
+    auto data = new char[8<<20];
+    file->seek_data(0, vsize, segs);
+    LOG_INFO("flattern segments count: `", segs.size());
+    for (auto m : segs) {
+        auto readn = file->pread(data, m.length*ALIGNMENT, m.offset * ALIGNMENT);
+        EXPECT_EQ(readn, fmerged->pwrite(data, readn, m.offset * ALIGNMENT));
+    }
+    verify_file(fmerged);
     delete file;
+    delete fmerged;
+    delete[] data;
 }
 
+
 TEST_F(FileTest3, sparsefile_close_seal) {
     CleanUp();
     cout << "generating " << FLAGS_layers << " RO layers by randwrite()" << endl;

src/tools/CMakeLists.txt

@@ -2,6 +2,11 @@ add_executable(overlaybd-commit overlaybd-commit.cpp)
 target_include_directories(overlaybd-commit PUBLIC ${PHOTON_INCLUDE_DIR})
 target_link_libraries(overlaybd-commit photon_static overlaybd_image_lib)
 
+add_executable(overlaybd-merge overlaybd-merge.cpp)
+target_include_directories(overlaybd-merge PUBLIC ${PHOTON_INCLUDE_DIR})
+target_link_libraries(overlaybd-merge photon_static overlaybd_image_lib)
+
+
 add_executable(overlaybd-create overlaybd-create.cpp)
 target_include_directories(overlaybd-create PUBLIC ${PHOTON_INCLUDE_DIR})
 target_link_libraries(overlaybd-create photon_static overlaybd_lib)
@@ -30,6 +35,8 @@ install(TARGETS
     overlaybd-create
     overlaybd-zfile
     overlaybd-apply
+    overlaybd-merge
+
     turboOCI-apply
     DESTINATION /opt/overlaybd/bin
 )