Provide write support

[GoogleCodeExporter]

pCacheFS is currently a read-only filesystem, but it would become much more 
useful if it supported writes.

The write support will be very simple: any writes are written through 
(synchronously) to the underlying filesystem and then to the cache. This 
ensures that if the write to the underlying filesystem fails, the cache is not 
updated.

This feature should support file writes, creates and deletes.

Original issue reported on code.google.com by [email protected] on 22 Dec 2012 at 1:18

[GoogleCodeExporter]

Original comment by [email protected] on 22 Dec 2012 at 1:19