On Tue, Sep 27, 2016 at 08:57:41AM +0800, Chao Yu wrote:
> Hi Jaegeuk,
>
> On 2016/9/27 2:33, Jaegeuk Kim wrote:
> > Hi Chao,
> >
> > On Tue, Sep 27, 2016 at 12:09:52AM +0800, Chao Yu wrote:
> >> From: Chao Yu <yuch...@huawei.com>
> >>
> >> In sync_node_pages, we won't check and commit last merged pages in private
> >> bio cache of f2fs, as these pages were taged as writeback, someone who is
> >> waiting for writebacking of the page will be blocked until the cache was
> >> committed by someone else.
> >>
> >> We need to commit node type bio cache to avoid potential deadlock or long
> >> delay of waiting writeback.
> >>
> >> Signed-off-by: Chao Yu <yuch...@huawei.com>
> >> ---
> >> fs/f2fs/node.c | 11 +++++++++--
> >> 1 file changed, 9 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> >> index 9faddcd..f73f774 100644
> >> --- a/fs/f2fs/node.c
> >> +++ b/fs/f2fs/node.c
> >> @@ -1416,6 +1416,7 @@ int sync_node_pages(struct f2fs_sb_info *sbi, struct
> >> writeback_control *wbc)
> >> struct pagevec pvec;
> >> int step = 0;
> >> int nwritten = 0;
> >> + int ret = 0;
> >>
> >> pagevec_init(&pvec, 0);
> >>
> >> @@ -1436,7 +1437,8 @@ next_step:
> >>
> >> if (unlikely(f2fs_cp_error(sbi))) {
> >> pagevec_release(&pvec);
> >> - return -EIO;
> >> + ret = -EIO;
> >> + goto out;
> >> }
> >>
> >> /*
> >> @@ -1487,6 +1489,8 @@ continue_unlock:
> >>
> >> if (NODE_MAPPING(sbi)->a_ops->writepage(page, wbc))
> >> unlock_page(page);
> >> + else
> >> + nwritten++;
> >>
> >> if (--wbc->nr_to_write == 0)
> >> break;
> >> @@ -1504,7 +1508,10 @@ continue_unlock:
> >> step++;
> >> goto next_step;
> >> }
> >> - return nwritten;
> >> +out:
> >> + if (nwritten)
> >> + f2fs_submit_merged_bio(sbi, NODE, WRITE);
> >
> > IIRC, we don't need to flush this, since f2fs_submit_merged_bio_cond() would
> > handle this in f2fs_wait_on_page_writeback().
>
> Yes, it covers all the cases in f2fs private codes, but there are still some
> codes in mm or fs directory, and they didn't use f2fs_wait_on_page_writeback
> when waiting page writeback. Such as do_writepages && filemap_fdatawait in
> __writeback_single_inode...
The do_writepages() is okay, which will call f2fs_write_node_pages().
The __writeback_single_inode() won't do filemap_fdatawait() with WB_SYNC_ALL.
We don't need to take care of truncation as well.
Any missing one?
>
> Thanks,
>
> >
> > Thanks,
> >
> >> + return ret;
> >> }
> >>
> >> int wait_on_node_pages_writeback(struct f2fs_sb_info *sbi, nid_t ino)
> >> --
> >> 2.7.2
> >
> > .
> >
