On 01/26, Gaoxiang (OS) wrote:
> Hi Jaegeuk and Chao,
>
> On 2018/1/26 9:36, Chao Yu wrote:
> > On 2018/1/26 6:06, Jaegeuk Kim wrote:
> >>
> >> Then, we don't need to wait for this as well as wait_on_all_pages_writeback()
> >> in the early stage in do_checkpoint()?
> >>
> >> So, it seems like we can modify like below:
> >>
> >> ---
> >> 1. while (get_pages())
> >> sync_meta_pages()
> >> 2. if (enabled_nat_bits())
> >> while (get_pages())
> >> sync_meta_pages()
> >>
> >> 3. wait_on_all_pages_writeback()
> >> -> remove
> >
> > Would meta area across two devices? if it would, we need to wait all meta
> > be persisted in second device before f2fs_flush_device_cache?
> >
> >>
> >> 4. f2fs_flush_device_cache()
-> remove
> >>
> >> 5. update_meta_page() <- for first cp_block
> >>
> >> 6. update_meta_page()... <- payload
> >>
> >> 7. orphan writes
> >>
> >> 8. node_summary writes
> >>
> >> 9. update_meta_page() <- for last cp_block
> >> -> remove
> >
>
> - /* writeout checkpoint block */
> - update_meta_page(sbi, ckpt, start_blk);
> -
> - /* wait for previous submitted node/meta pages writeback */
> - wait_on_all_pages_writeback(sbi);
> -
> - if (unlikely(f2fs_cp_error(sbi)))
> - return -EIO;
> -
> Could also be removed, too?
>
> filemap_fdatawait_range(NODE_MAPPING(sbi), 0, LLONG_MAX);
> filemap_fdatawait_range(META_MAPPING(sbi), 0, LLONG_MAX);
-> remove
Hmm, think so.
>
>
> > 9.1 sync_meta_pages(META) to make sure all meta IOs are issued.
> >
>
> If I understand correctly, I have the same questions with Chao.
> It seems that META doesn't have another flush mechanism (eg. flush
> thread) other than sync_meta_pages?
9.2 f2fs_flush_device_cache(), if we have multiple devices.
>
> >>
> >> 10. wait_on_all_pages_writeback()
10.1. (f2fs_cp_error())
return -EIO;
> >>
> >> ----
> >> Add) 11. commit_checkpoint()
> >> - update_meta_page() <- for last cp_block
> >> - sync_meta_pages(META_FLUSH)
> >>
> >> We don't need to wait for page_writeback any more.
> >>
>
>
> Apart from that, I think we should "wait_on_all_pages_writeback(sbi);"
> after META_FLUSH in case for pulluting the next checkpoint when the last
> cp block is failed to write with FUA?
Next cp block won't be written by 10.1.
>
>
> Thanks all,
>
> >>>
> >>> @@ -1313,10 +1337,15 @@ static int do_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
> >>> sbi->last_valid_block_count = sbi->total_valid_block_count;
> >>> percpu_counter_set(&sbi->alloc_valid_block_count, 0);
> >>>
> >>> - /* Here, we only have one bio having CP pack */
> >>> - sync_meta_pages(sbi, META_FLUSH, LONG_MAX, FS_CP_META_IO);
> >>> + /* Here, we have one bio having CP pack except cp pack 2 page */
> >>> + sync_meta_pages(sbi, META, LONG_MAX, FS_CP_META_IO);
> >>>
> >>> /* wait for previous submitted meta pages writeback */
> >>> + if (!test_opt(sbi, NOBARRIER))
> >>
> >> The above has nothing to do with this patch.
> >
> > We only need to use wait_on_all_pages_writeback to keep writeback order of
> > previous metadata and last cp pack metadata if barrier is on?
> >
> > Thanks,
> >
> >>
> >>> + wait_on_all_pages_writeback(sbi);
> >>> +
> >>> + /* barrier and flush checkpoint cp pack 2 page */
> >>> + commit_checkpoint(sbi, ckpt, start_blk);
> >>> wait_on_all_pages_writeback(sbi);
> >>>
> >>> release_ino_entry(sbi, false);
> >>> --
> >>> 2.1.4
> >>
> >> .
> >>
> >
