Changes between Version 17 and Version 18 of FSDesign

Timestamp:

2009-11-17T11:16:58Z (14 years ago)

Author:

Jakub Jermář

Comment:

—

FSDesign

@@ -129 +129 @@
 In the above code snippet, the ''vfs_rdwr()'' function first translates the file handle using the ''vfs_file_get()'' interface to a ''vfs_file_t'' structure and then locks the result. The VFS node is directly accessed in the two RW-lock lock operations at the end of the example.
 
-
-==== VFS backend ====
+=== VFS backend ===
 
 As soon as the VFS server knows the VFS node associated with the request, it either asks one of the endpoint file system servers to carry out the operation for it or, when it has enough information, it completes the operation itself. For example, VFS handles the VFS_IN_SEEK request, which corresponds to the POSIX call ''lseek()'', entirely on its own, because it just manipulates the current position pointer within the respective ''vfs_file_t'' structure. In the worst case, when seeking to the end of the file, VFS needs to know the size of the file, but this is not a problem, because the server maintains the current file size in each VFS node.
 
+We refer to the part which communicates with the endpoint file system servers as to VFS backend. VFS backend knows the handle of the endpoint file system (and also of the underlying device) from the VFS node, so it can use it to obtain an IPC phone and communicate with it.