Hi Gu,

2014-03-07 (금), 18:43 +0800, Gu Zheng:
> Previously, we ra_sum_pages to pre-read contiguous pages as more
> as possible, and if we fail to alloc more pages, an ENOMEM error
> will be reported upstream, even though we have alloced some pages
> yet. In fact, we can use the available pages to do the job partly,
> and continue the rest in the following circle. Only reporting ENOMEM
> upstream if we really can not alloc any available page.
> 
> And another fix is ignoring dealing with the following pages if an
> EIO occurs when reading page from page_list.
> 
> Signed-off-by: Gu Zheng <guz.f...@cn.fujitsu.com>
> ---
>  fs/f2fs/node.c    |   44 ++++++++++++++++++++------------------------
>  fs/f2fs/segment.c |    7 +++++--
>  2 files changed, 25 insertions(+), 26 deletions(-)
> 
> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> index 8787469..4b7861d 100644
> --- a/fs/f2fs/node.c
> +++ b/fs/f2fs/node.c
> @@ -1588,15 +1588,8 @@ static int ra_sum_pages(struct f2fs_sb_info *sbi, 
> struct list_head *pages,
>       for (; page_idx < start + nrpages; page_idx++) {
>               /* alloc temporal page for read node summary info*/
>               page = alloc_page(GFP_F2FS_ZERO);
> -             if (!page) {
> -                     struct page *tmp;
> -                     list_for_each_entry_safe(page, tmp, pages, lru) {
> -                             list_del(&page->lru);
> -                             unlock_page(page);
> -                             __free_pages(page, 0);
> -                     }
> -                     return -ENOMEM;
> -             }
> +             if (!page)
> +                     break;
>  
>               lock_page(page);
>               page->index = page_idx;
> @@ -1607,7 +1600,8 @@ static int ra_sum_pages(struct f2fs_sb_info *sbi, 
> struct list_head *pages,
>               f2fs_submit_page_mbio(sbi, page, page->index, &fio);
>  
>       f2fs_submit_merged_bio(sbi, META, READ);
> -     return 0;
> +
> +     return page_idx - start;
>  }
>  
>  int restore_node_summary(struct f2fs_sb_info *sbi,
> @@ -1630,28 +1624,30 @@ int restore_node_summary(struct f2fs_sb_info *sbi,
>               nrpages = min(last_offset - i, bio_blocks);
>  
>               /* read ahead node pages */
> -             err = ra_sum_pages(sbi, &page_list, addr, nrpages);
> -             if (err)
> -                     return err;
> +             nrpages = ra_sum_pages(sbi, &page_list, addr, nrpages);
> +             if (!nrpages)
> +                     return -ENOMEM;
>  
>               list_for_each_entry_safe(page, tmp, &page_list, lru) {
> -

Here we can just add:
                        if (err)
                                goto skip;
                        lock_page();
                        ...
                        unlock_page();
                skip:
                        list_del();
                        __free_pages();

IMO, it's more neat, so if you have any objection, let me know.
Otherwise, I'll handle this by myself. :)
Thanks,

> -                     lock_page(page);
> -                     if (unlikely(!PageUptodate(page))) {
> -                             err = -EIO;
> -                     } else {
> -                             rn = F2FS_NODE(page);
> -                             sum_entry->nid = rn->footer.nid;
> -                             sum_entry->version = 0;
> -                             sum_entry->ofs_in_node = 0;
> -                             sum_entry++;
> +                     if (!err) {
> +                             lock_page(page);
> +                             if (unlikely(!PageUptodate(page))) {
> +                                     err = -EIO;
> +                             } else {
> +                                     rn = F2FS_NODE(page);
> +                                     sum_entry->nid = rn->footer.nid;
> +                                     sum_entry->version = 0;
> +                                     sum_entry->ofs_in_node = 0;
> +                                     sum_entry++;
> +                             }
> +                             unlock_page(page);
>                       }
>  
>                       list_del(&page->lru);
> -                     unlock_page(page);
>                       __free_pages(page, 0);
>               }
>       }
> +
>       return err;
>  }
>  
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 199c964..b3f8431 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -1160,9 +1160,12 @@ static int read_normal_summaries(struct f2fs_sb_info 
> *sbi, int type)
>                               ns->ofs_in_node = 0;
>                       }
>               } else {
> -                     if (restore_node_summary(sbi, segno, sum)) {
> +                     int err;
> +
> +                     err = restore_node_summary(sbi, segno, sum);
> +                     if (err) {
>                               f2fs_put_page(new, 1);
> -                             return -EINVAL;
> +                             return err;
>                       }
>               }
>       }

-- 
Jaegeuk Kim
Samsung

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