Re: [PATCH] f2fs: fix to redirty page if fail to gc data page

From: Jaegeuk Kim
Date: Fri Jun 03 2016 - 01:09:13 EST


On Tue, May 31, 2016 at 02:10:50PM +0800, Chao Yu wrote:
> Hi Jaegeuk,
>
> On 2016/5/30 10:37, Jaegeuk Kim wrote:
> > Hi Chao,
> >
> > On Sat, May 21, 2016 at 01:19:11PM +0800, Chao Yu wrote:
> >> From: Chao Yu <yuchao0@xxxxxxxxxx>
> >>
> >> If we fail to move data page during foreground GC, we should give another
> >> chance to writeback that page which was set dirty previously by writer.
> >>
> >> Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
> >> ---
> >> fs/f2fs/gc.c | 5 ++++-
> >> 1 file changed, 4 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> >> index 38d56f6..ee213a8 100644
> >> --- a/fs/f2fs/gc.c
> >> +++ b/fs/f2fs/gc.c
> >> @@ -653,12 +653,15 @@ static void move_data_page(struct inode *inode, block_t bidx, int gc_type)
> >> .page = page,
> >> .encrypted_page = NULL,
> >> };
> >> + bool is_dirty = PageDirty(page);
> >> +
> >> set_page_dirty(page);
> >> f2fs_wait_on_page_writeback(page, DATA, true);
> >> if (clear_page_dirty_for_io(page))
> >> inode_dec_dirty_pages(inode);
> >> set_cold_data(page);
> >> - do_write_data_page(&fio);
> >> + if (do_write_data_page(&fio) && is_dirty)
> >> + set_page_dirty(page);
> >
> > If this page is truncated with -ENOENT, we don't need to set it dirty again.
>
> Agree
>
> > I expect that, if we get an error here, do_garbage_collect() would retry FG_GC
>
> IIRC, you have reworked the FG_GC flows changed from an infinite loop to trying
> do the movement just one time. Here, I think if there are just few of blocks are
> failed to be moved, we can give one more time for retrying. How do you think?

Mostly I expected here -ENOENT caused by race condition.
Do we have another expectation?

Thanks,

>
> > again.
> >
> > Thanks,
> >
> >> clear_cold_data(page);
> >> }
> >> out:
> >> --
> >> 2.7.2
> > .
> >