Re: MM question

[Magnus Ahltorp <map@stacken.kth.se>]

> Okay, you probably don't want to implement readpage, just read and write,
> so your read will look like:
> 
> This will make your inodes relatively lightweight, and avoid having in
> memory pages attached to your inode which would be duplicates of those
> attached to the ext2 inode.

Doesn't this mean that the read functions will be called every time
something has to be read? What about mmap?

> Readpage is called by generic_file_read and page fault handlers to pull
> the page into the page cache.  In the case of writing, you need to update
> the page cache, as well as commit the write to whatever backstore is used. 
> Since you've got the entire file cached (right?), just making use of the
> ext2 inode's read & write will keep the cache coherent and reduce the
> amount work you need to do. 

At the moment, we do whole file caching, but that might change in the
future.

/Magnus
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