use diff_storage_filename instead diff_storage_fd

include/linux/blksnap.h

@@ -238,14 +238,14 @@ struct blksnap_version {
  *
  * @diff_storage_limit_sect:
  *	The maximum allowed difference storage size in sectors.
- * @diff_storage_fd:
- *	The difference storage file descriptor.
+ * @diff_storage_filename:
+ *	The difference storage file name.
  * @id:
  *	Generated new snapshot ID.
  */
 struct blksnap_snapshot_create {
 	__u64 diff_storage_limit_sect;
-	__u32 diff_storage_fd;
+	__u64 diff_storage_filename;
 	struct blksnap_uuid id;
 };
 

lib/blksnap/Snapshot.cpp

@@ -83,18 +83,9 @@ void CSnapshot::Version(struct blksnap_version& version)
 
 std::shared_ptr<CSnapshot> CSnapshot::Create(const std::string& filePath, const unsigned long long limit)
 {
-    int flags = O_RDWR | O_EXCL;
-
-    if (fs::is_directory(filePath))
-            flags |= O_TMPFILE;
-    else if (!fs::is_regular_file(filePath) && !isBlockFile(filePath))
-        throw std::invalid_argument("The filePath should have been either the name of a regular file, the name of a block device, or the directory for creating a temporary file.");
-
-    OpenFileHolder fd(filePath, flags, 0600);
-
     struct blksnap_snapshot_create param = {0};
     param.diff_storage_limit_sect = limit / 512;
-    param.diff_storage_fd = fd.Get();
+    param.diff_storage_filename = (__u64)filePath.c_str();
 
     auto ctl = OpenBlksnapCtl();
     if (::ioctl(ctl->Get(), IOCTL_BLKSNAP_SNAPSHOT_CREATE, &param))

tools/blksnap/main.cpp

@@ -680,20 +680,8 @@ class SnapshotCreateArgsProc : public IArgsProc
         if (!vm.count("file"))
             throw std::invalid_argument("Argument 'file' is missed.");
 
-        int flags = O_RDWR | O_EXCL;
         std::string filename = vm["file"].as<std::string>();
 
-        if (fs::is_directory(filename)) {
-            /* A temporary file (flag O_TMPFILE) is being created.
-             * Not available for all file systems.
-             * See: man open.
-             */
-            flags |= O_TMPFILE;
-        } else if (!fs::is_regular_file(filename) && !isBlockFile(filename))
-            throw std::invalid_argument("The value '"+filename+"' for the argument '--file' should have been either the name of a regular file, the name of a block device, or the directory for creating a temporary file.");
-
-        OpenFileHolder fd(filename, flags, 0600);
-
         unsigned long long limit = 0;
         unsigned long long multiple = 1;
         if (!vm.count("limit"))
@@ -713,7 +701,7 @@ class SnapshotCreateArgsProc : public IArgsProc
         }
 
         param.diff_storage_limit_sect = limit / 512;
-        param.diff_storage_fd = fd.Get();
+        param.diff_storage_filename = (__u64)filename.c_str();
         if (::ioctl(blksnapFd.get(), IOCTL_BLKSNAP_SNAPSHOT_CREATE, &param))
             throw std::system_error(errno, std::generic_category(), "Failed to create snapshot object.");