fs/ntfs3: Refactor ni_parse_reparse

Change argument from void* to struct REPARSE_DATA_BUFFER*
We copy data to buffer, so we can read it later in ntfs_read_mft.
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>

fs/ntfs3/frecord.c

@@ -1710,18 +1710,16 @@ int ni_new_attr_flags(struct ntfs_inode *ni, enum FILE_ATTRIBUTE new_fa)
 /*
  * ni_parse_reparse
  *
- * Buffer is at least 24 bytes.
+ * buffer - memory for reparse buffer header
  */
 enum REPARSE_SIGN ni_parse_reparse(struct ntfs_inode *ni, struct ATTRIB *attr,
-				   void *buffer)
+				   struct REPARSE_DATA_BUFFER *buffer)
 {
 	const struct REPARSE_DATA_BUFFER *rp = NULL;
 	u8 bits;
 	u16 len;
 	typeof(rp->CompressReparseBuffer) *cmpr;
 
-	static_assert(sizeof(struct REPARSE_DATA_BUFFER) <= 24);
-
 	/* Try to estimate reparse point. */
 	if (!attr->non_res) {
 		rp = resident_data_ex(attr, sizeof(struct REPARSE_DATA_BUFFER));
@@ -1807,6 +1805,9 @@ enum REPARSE_SIGN ni_parse_reparse(struct ntfs_inode *ni, struct ATTRIB *attr,
 		return REPARSE_NONE;
 	}
 
+	if (buffer != rp)
+		memcpy(buffer, rp, sizeof(struct REPARSE_DATA_BUFFER));
+
 	/* Looks like normal symlink. */
 	return REPARSE_LINK;
 }

fs/ntfs3/ntfs_fs.h

@@ -547,7 +547,7 @@ struct ATTR_FILE_NAME *ni_fname_type(struct ntfs_inode *ni, u8 name_type,
 				     struct ATTR_LIST_ENTRY **entry);
 int ni_new_attr_flags(struct ntfs_inode *ni, enum FILE_ATTRIBUTE new_fa);
 enum REPARSE_SIGN ni_parse_reparse(struct ntfs_inode *ni, struct ATTRIB *attr,
-				   void *buffer);
+				   struct REPARSE_DATA_BUFFER *buffer);
 int ni_write_inode(struct inode *inode, int sync, const char *hint);
 #define _ni_write_inode(i, w) ni_write_inode(i, w, __func__)
 int ni_fiemap(struct ntfs_inode *ni, struct fiemap_extent_info *fieinfo,