* mpage writepage question
@ 2005-02-03 16:37 Badari Pulavarty
2005-02-03 17:10 ` Sonny Rao
2005-02-03 18:52 ` Andrew Morton
0 siblings, 2 replies; 3+ messages in thread
From: Badari Pulavarty @ 2005-02-03 16:37 UTC (permalink / raw)
To: linux-fsdevel; +Cc: Andrew Morton
Hi Andrew,
I was wondering why mpage_writepage() is only "static" ?
Is the expectation that, filesystems use
.writepage == block_full_write_page
.writepages == mpage_writepages
? I am little confused on why we have 2 different ways to
do things ? block_full_write_page() seems to be creating
buffer heads, where as mpage_writepages() can do directly
bios. Shouldn't they be using mpage_writepage() instead of
block_full_write_page() ?
Thanks,
Badari
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: mpage writepage question
2005-02-03 16:37 mpage writepage question Badari Pulavarty
@ 2005-02-03 17:10 ` Sonny Rao
2005-02-03 18:52 ` Andrew Morton
1 sibling, 0 replies; 3+ messages in thread
From: Sonny Rao @ 2005-02-03 17:10 UTC (permalink / raw)
To: Badari Pulavarty; +Cc: linux-fsdevel, Andrew Morton
On Thu, Feb 03, 2005 at 08:37:19AM -0800, Badari Pulavarty wrote:
> Hi Andrew,
>
> I was wondering why mpage_writepage() is only "static" ?
>
> Is the expectation that, filesystems use
>
> .writepage == block_full_write_page
> .writepages == mpage_writepages
>
> ? I am little confused on why we have 2 different ways to
> do things ? block_full_write_page() seems to be creating
> buffer heads, where as mpage_writepages() can do directly
> bios. Shouldn't they be using mpage_writepage() instead of
> block_full_write_page() ?
>
I was wondering the same thing too.
My only guess is that if you keep the buffer_head attached to the
page, then you don't need to call get_block again if you write the
same page back, and I suppose the fs get_block function could be
expensive and/or require I/O.
Sonny
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: mpage writepage question
2005-02-03 16:37 mpage writepage question Badari Pulavarty
2005-02-03 17:10 ` Sonny Rao
@ 2005-02-03 18:52 ` Andrew Morton
1 sibling, 0 replies; 3+ messages in thread
From: Andrew Morton @ 2005-02-03 18:52 UTC (permalink / raw)
To: Badari Pulavarty; +Cc: linux-fsdevel
Badari Pulavarty <pbadari@us.ibm.com> wrote:
>
> Hi Andrew,
>
> I was wondering why mpage_writepage() is only "static" ?
Good question.
> Is the expectation that, filesystems use
>
> .writepage == block_full_write_page
> .writepages == mpage_writepages
>
> ? I am little confused on why we have 2 different ways to
> do things ? block_full_write_page() seems to be creating
> buffer heads, where as mpage_writepages() can do directly
> bios. Shouldn't they be using mpage_writepage() instead of
> block_full_write_page() ?
I have a feeling that we used to have a single-page writepage function in
fs/mpage.c a long time ago. The current mpage_writepage() is an
internal-only function and isn't suitable and should really be renamed.
But it certainly looks doable.
The new writepage function would need to fall back to
__block_write_full_page() in many situations, but the current code in there
does all that.
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2005-02-03 18:52 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2005-02-03 16:37 mpage writepage question Badari Pulavarty
2005-02-03 17:10 ` Sonny Rao
2005-02-03 18:52 ` Andrew Morton
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).