Re: inode->i_dirty_buffers redundant ?

[Marcelo Tosatti]

On Thu, 25 Jan 2001, Stephen C. Tweedie wrote:

> Hi,
> 
> On Thu, Jan 25, 2001 at 04:17:30PM +0530, V Ganesh wrote:
> 
> > so i_dirty_buffers contains buffer_heads of pages coming from write() as
> > well as metadata buffers from mark_buffer_dirty_inode(). a dirty MAP_SHARED
> > page which has been write()n to will potentially exist in both lists.
> > won't doing a set_dirty_page() instead of buffer_insert_inode_queue() in
> > __block_commit_write() make things much simpler ? then we'd have i_dirty_buffers
> > having _only_ metadata, and all data pages in the i_mapping->*_pages lists.
> 
> That would only complicate things: it would mean we'd have to scan
> both lists on fsync instead of just the one, for example.  There are a
> number of places where we need buffer lists for dirty data anyway,
> such as for bdflush's background sync to disk.  We also maintain the
> per-page buffer lists as caches of the virtual-to-physical mapping to
> avoid redundant bmap()ping.  

Btw, 

We probably want another kind of "IO buffer" abstraction for 2.5 which can
support buffer's bigger than PAGE_SIZE. 

Do you have any thoughts on that, Stephen?