Hans Reiser <[EMAIL PROTECTED]> writes:
> I feel we should encourage Linus to allow the following:
>
> * unions in struct buffer_head and struct page containing filesystem specific
> fields comparable to the union in struct inode.
No.
In struct buffer_head I don't have problems.
In struct page (you don't want to pay the overhead for every page of memory)...
There is the buffer_head *bh pointer that could be made more generic.
>
> * a filesystem operation which flushes to disk a buffer or page, and leaves it
> to the filesystem whether to flush a whole commit along with it, or a whole
> bunch of semantically adjacent buffers, or to repack the buffers before writing
> them, or to write a whole bunch of semantically nearby buffers, or to fill the
> rest of the RAID stripe, or assign a block number to the page, or mark the page
> copy_on_write, or whatever else it wants.
Or allocate bounce buffers, for high memory pages. . .
Though I don't think copy_on_write and (whatever else it wants)
are necessarily hot ideas. There need to be some constraints.
> Do the rest of you agree?
I agree that it is a good idea. Exactly how it should, and if it
should be implemented for 2.3 is a second question.
There is also the related issue of the page lock not currently working
for NFS (it needs some I/O locking).
Since I've been pushing for this for a while. I'll see if there
is anything that could be considered a ``bug fix'' doable yet in 2.3
The recent patch to improve fdatasync performance is also somewhat
related.
Eric
