Updated linux/kernel/api/vfs_fallocate

linux/kernel/api/vfs_fallocate.md

@@ -1,11 +1,16 @@
 I don't know if this correct or not, but here a manpage ugly draft:
 
+#### SYNOPSIS
 ```
-vfs_fallocate ( struct file *file, int mode, off_t offset, off_t len )
+int vfs_fallocate ( struct file *file, int mode, off_t offset, off_t len )
 ```
 
+#### DESCRIPTION
+
 Read `man 2 fallocate`.
 
+#### EXAMPLES
+
 A wrapper example:
 ```
 int file_allocate ( struct file *file, int mode, off_t offset, off_t len )
@@ -21,4 +26,8 @@ int file_allocate ( struct file *file, int mode, off_t offset, off_t len )
 
   return error;
 }
-```
+```
+
+#### RETURN VALUE
+
+On success, `vfs_allocate()` resturns zero, otherwise non-zero.