Resolve code review problems

Author: nickyc975

doc/en/nvmeof_generic_transport.md

@@ -215,7 +215,7 @@ Assume the metadata service address is `http://127.0.0.1:8080/metadata` (using H
 ```bash
 ./build/mooncake-transfer-engine/example/transfer_engine_nvmeof_generic_bench \
     --local_server_name=127.0.0.1:8081 \
-    --metadata_server=http://127.0.0.0.0:8080/metadata \
+    --metadata_server=http://127.0.0.1:8080/metadata \
     --mode=target \
     --trtype=tcp \
     --traddr=127.0.0.1 \

mooncake-store/src/allocator.cpp

@@ -79,7 +79,8 @@ CachelibBufferAllocator::CachelibBufferAllocator(std::string segment_name,
 
     LOG_ASSERT(header_region_start_);
 
-    // Add a padding to base to support zero-based buffers.
+    /// Zero is not a valid buffer base address for CachelibAllocator. Therefore,
+    /// we add a padding to the base to support zero-based buffers.
     auto padded_base = base + facebook::cachelib::Slab::kSize;
 
     // Initialize the CacheLib MemoryAllocator.

mooncake-store/src/client.cpp

@@ -47,18 +47,20 @@ static size_t getFileSize(const std::string& file) {
     int fd = open(file.c_str(), O_RDONLY);
     if (fd < 0) {
         LOG(ERROR) << "Failed to open file " << file << ", errno=" << errno;
-        goto out;
+        return 0;
     }
 
     rc = fstat(fd, &st);
     if (rc < 0) {
         LOG(ERROR) << "Failed fstat on file " << file << ", errno=" << errno;
-        goto close_file;
+        close(fd);
+        return 0;
     }
 
     if (S_ISLNK(st.st_mode)) {
         LOG(ERROR) << "File " << file << " is a symbolic link";
-        goto close_file;
+        close(fd);
+        return 0;
     }
 
     if (S_ISBLK(st.st_mode) || S_ISCHR(st.st_mode)) {
@@ -72,9 +74,7 @@ static size_t getFileSize(const std::string& file) {
         size = st.st_size;
     }
 
-close_file:
     close(fd);
-out:
     return size;
 }
 

mooncake-transfer-engine/example/transfer_engine_nvmeof_generic_bench.cpp

@@ -268,15 +268,17 @@ static size_t getFileSize(const std::string &file) {
 
     int fd = open(file.c_str(), O_RDONLY);
     if (fd < 0) {
-        goto err_out;
+        return 0;
     }
 
     if (fstat(fd, &st) != 0) {
-        goto err_close_file;
+        close(fd);
+        return 0;
     }
 
     if (S_ISLNK(st.st_mode)) {
-        goto err_close_file;
+        close(fd);
+        return 0;
     }
 
     if (S_ISBLK(st.st_mode) || S_ISCHR(st.st_mode)) {
@@ -285,9 +287,7 @@ static size_t getFileSize(const std::string &file) {
         size = st.st_size;
     }
 
-err_close_file:
     close(fd);
-err_out:
     return size;
 }