Add support for bsdiff of file system metadata blocks

delta_diff_generator_unittest.cc

Index: delta_diff_generator_unittest.cc
diff --git a/delta_diff_generator_unittest.cc b/delta_diff_generator_unittest.cc
index 2a703994b66ecfa4bd7fc4656342b65295e45ece..dffe07a0c905d8b3d72f76b9d06d3cf3d9ed16f1 100644
--- a/delta_diff_generator_unittest.cc
+++ b/delta_diff_generator_unittest.cc
@@ -6,13 +6,14 @@
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <unistd.h>
+#include <gtest/gtest.h>

[petkov, 2010/12/10 00:46:55]

style is as below, with blank lines between groups:

c headers <>
c++ headers <>
library headers <>
project headers ""

[thieule, 2010/12/14 23:11:21]

Done.

 #include <set>
 #include <sstream>
 #include <string>
 #include <utility>
 #include <vector>
-#include <gtest/gtest.h>
 #include "base/logging.h"
+#include "base/string_util.h"
 #include "update_engine/cycle_breaker.h"
 #include "update_engine/delta_diff_generator.h"
 #include "update_engine/delta_performer.h"
@@ -729,6 +730,132 @@ TEST_F(DeltaDiffGeneratorTest, RunAsRootAssignTempBlocksReuseTest) {
   EXPECT_EQ(OP_REPLACE_BZ, graph[5].op.type());
 }
 
+TEST_F(DeltaDiffGeneratorTest, RunAsRootReadMetadataDissimilarFileSystems) {
+  string a_img, b_img;
+  EXPECT_TRUE(utils::MakeTempFile("/tmp/a_img.XXXXXX", &a_img, NULL));
+  ScopedPathUnlinker a_img_unlinker(a_img);
+  EXPECT_TRUE(utils::MakeTempFile("/tmp/b_img.XXXXXX", &b_img, NULL));
+  ScopedPathUnlinker b_img_unlinker(b_img);
+
+  CreateEmptyExtImageAtPath(a_img, 10485759, 4096);
+  CreateEmptyExtImageAtPath(b_img, 11534336, 4096);
+
+  Graph graph;
+  vector<Block> blocks;
+  EXPECT_TRUE(DeltaDiffGenerator::DeltaReadMetadata(&graph,
+                                                    &blocks,
+                                                    a_img,
+                                                    b_img,
+                                                    0,
+                                                    NULL));
+  EXPECT_EQ(graph.size(), 0);
+
+  CreateEmptyExtImageAtPath(a_img, 10485759, 4096);
+  CreateEmptyExtImageAtPath(b_img, 10485759, 8192);
+
+  graph.clear();
+  blocks.clear();
+  EXPECT_TRUE(DeltaDiffGenerator::DeltaReadMetadata(&graph,
+                                                    &blocks,
+                                                    a_img,
+                                                    b_img,
+                                                    0,
+                                                    NULL));
+  EXPECT_EQ(graph.size(), 0);
+}
+
+TEST_F(DeltaDiffGeneratorTest, RunAsRootReadMetadata) {
+  string a_img, b_img, data_file;
+  EXPECT_TRUE(utils::MakeTempFile("/tmp/a_img.XXXXXX", &a_img, NULL));
+  ScopedPathUnlinker a_img_unlinker(a_img);
+  EXPECT_TRUE(utils::MakeTempFile("/tmp/b_img.XXXXXX", &b_img, NULL));
+  ScopedPathUnlinker b_img_unlinker(b_img);
+  EXPECT_TRUE(utils::MakeTempFile("/tmp/data_file.XXXXXX", &data_file, NULL));
+  ScopedPathUnlinker data_file_unlinker(data_file);
+
+  const size_t image_size = (256 * 1024 * 1024); // Enough for 2 block groups
+  const int block_size = 4096;
+  CreateEmptyExtImageAtPath(a_img, image_size, block_size);
+
+  // Create a file large enough to create an indirect block
+  {
+    string a_img_mnt;
+    ScopedLoopMounter a_img_mount(a_img, &a_img_mnt, 0);
+    System(StringPrintf("dd if=/dev/zero of=%s/test_file bs=%d count=%d",
+                        a_img_mnt.c_str(), block_size, EXT2_NDIR_BLOCKS + 1));
+  }
+
+  System(StringPrintf("cp %s %s", a_img.c_str(), b_img.c_str()));
+
+  int fd = open(data_file.c_str(), O_RDWR | O_CREAT, S_IRWXU);
+  EXPECT_NE(fd, -1);
+  ScopedFdCloser fd_closer(&fd);
+
+  Graph graph;
+  vector<Block> blocks(image_size / block_size);
+  off_t data_file_size;
+  EXPECT_TRUE(DeltaDiffGenerator::DeltaReadMetadata(&graph,
+                                                    &blocks,
+                                                    a_img,
+                                                    b_img,
+                                                    fd,
+                                                    &data_file_size));
+
+  // There are 12 metadata that we look for:
+  //   - Block group 0 metadata (superblock, group descriptor, bitmaps, etc)
+  //       - Chunk 0, 1, 2, 3
+  //   - Block group 1 metadata
+  //       - Chunk 0, 1, 2, 3
+  //   - Root directory (inode 2)
+  //   - Journal (inode 8)
+  //   - lost+found directory (inode 11)
+  //   - test_file indirect block (inode 12)
+  struct {
+    string metadata_name;
+    off_t start_block; // Set to -1 to skip start block verification
+    off_t num_blocks; // Set to -1 to skip num blocks verification
+  } exp_results[] =
+      {{"<rootfs-bg-0-0-metadata>", 0, 260},
+       {"<rootfs-bg-0-1-metadata>", 260, 260},
+       {"<rootfs-bg-0-2-metadata>", 520, 260},
+       {"<rootfs-bg-0-3-metadata>", 780, 263},
+       {"<rootfs-bg-1-0-metadata>", 32768, 260},
+       {"<rootfs-bg-1-1-metadata>", 33028, 260},
+       {"<rootfs-bg-1-2-metadata>", 33288, 260},
+       {"<rootfs-bg-1-3-metadata>", 33548, 263},
+       {"<rootfs-inode-2-metadata>", -1, 1},
+       {"<rootfs-inode-8-metadata>", -1, 4101},
+       {"<rootfs-inode-11-metadata>", -1, 4},
+       {"<rootfs-inode-12-metadata>", -1, 1}};
+
+  int num_exp_results = sizeof(exp_results) / sizeof(exp_results[0]);
+  EXPECT_EQ(graph.size(), num_exp_results);
+
+  for (int i = 0; i < num_exp_results; i++) {
+    Vertex& vertex = graph[i];
+    DeltaArchiveManifest_InstallOperation& op = vertex.op;
+
+    EXPECT_STRCASEEQ(vertex.file_name.c_str(),
+                     exp_results[i].metadata_name.c_str());
+
+    EXPECT_EQ(op.src_extents().size(), op.dst_extents().size());
+    for (int e = 0; e < op.src_extents().size(); e++) {
+      EXPECT_EQ(op.src_extents(e).start_block(),
+                op.dst_extents(e).start_block());
+      EXPECT_EQ(op.src_extents(e).num_blocks(),
+                op.dst_extents(e).num_blocks());
+    }
+
+    if (exp_results[i].start_block != -1) {
+      EXPECT_EQ(op.src_extents(0).start_block(), exp_results[i].start_block);
+    }
+
+    if (exp_results[i].num_blocks != -1) {
+      EXPECT_EQ(op.src_extents(0).num_blocks(), exp_results[i].num_blocks);
+    }
+  }
+}
+
 TEST_F(DeltaDiffGeneratorTest, CreateScratchNodeTest) {
   Vertex vertex;
   DeltaDiffGenerator::CreateScratchNode(12, 34, &vertex);