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Date: Thu, 18 Dec 2014 00:19:56 +0900
From: Changman Lee <cm224.lee@...il.com>
To: Chao Yu <chao2.yu@...sung.com>
Cc: Jaegeuk Kim <jaegeuk@...nel.org>,
Changman Lee <cm224.lee@...sung.com>,
"linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
linux-f2fs-devel@...ts.sourceforge.net
Subject: Re: [f2fs-dev] [PATCH v2] f2fs: use ra_meta_pages to simplify
readahead code in restore_node_summary
Hi,
Is there any reason to use truncate_inode_pages_range instead of
invalidate_mapping_pages?
IMHO, it seems nice to just use invalidate_mapping_pages because pages
of meta_inode shouldn't be dirty, locked, under writeback or mapped in
this function.
If there is my misunderstanding, let me know.
Thanks,
Reviewed-by: Changman Lee <cm224.lee@...sung.com>
2014-12-17 19:10 GMT+09:00 Chao Yu <chao2.yu@...sung.com>:
> Use more common function ra_meta_pages() with META_POR to readahead node blocks
> in restore_node_summary() instead of ra_sum_pages(), hence we can simplify the
> readahead code there, and also we can remove unused function ra_sum_pages().
>
> changes from v1:
> o fix one bug when using truncate_inode_pages_range which is pointed out by
> Jaegeuk Kim.
>
> Signed-off-by: Chao Yu <chao2.yu@...sung.com>
> ---
> fs/f2fs/node.c | 68 +++++++++++++---------------------------------------------
> 1 file changed, 15 insertions(+), 53 deletions(-)
>
> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> index 5aa54a0..ab48b4c 100644
> --- a/fs/f2fs/node.c
> +++ b/fs/f2fs/node.c
> @@ -1726,80 +1726,42 @@ int recover_inode_page(struct f2fs_sb_info *sbi, struct page *page)
> return 0;
> }
>
> -/*
> - * ra_sum_pages() merge contiguous pages into one bio and submit.
> - * these pre-read pages are allocated in bd_inode's mapping tree.
> - */
> -static int ra_sum_pages(struct f2fs_sb_info *sbi, struct page **pages,
> - int start, int nrpages)
> -{
> - struct inode *inode = sbi->sb->s_bdev->bd_inode;
> - struct address_space *mapping = inode->i_mapping;
> - int i, page_idx = start;
> - struct f2fs_io_info fio = {
> - .type = META,
> - .rw = READ_SYNC | REQ_META | REQ_PRIO
> - };
> -
> - for (i = 0; page_idx < start + nrpages; page_idx++, i++) {
> - /* alloc page in bd_inode for reading node summary info */
> - pages[i] = grab_cache_page(mapping, page_idx);
> - if (!pages[i])
> - break;
> - f2fs_submit_page_mbio(sbi, pages[i], page_idx, &fio);
> - }
> -
> - f2fs_submit_merged_bio(sbi, META, READ);
> - return i;
> -}
> -
> int restore_node_summary(struct f2fs_sb_info *sbi,
> unsigned int segno, struct f2fs_summary_block *sum)
> {
> struct f2fs_node *rn;
> struct f2fs_summary *sum_entry;
> - struct inode *inode = sbi->sb->s_bdev->bd_inode;
> block_t addr;
> int bio_blocks = MAX_BIO_BLOCKS(sbi);
> - struct page *pages[bio_blocks];
> - int i, idx, last_offset, nrpages, err = 0;
> + int i, idx, last_offset, nrpages;
>
> /* scan the node segment */
> last_offset = sbi->blocks_per_seg;
> addr = START_BLOCK(sbi, segno);
> sum_entry = &sum->entries[0];
>
> - for (i = 0; !err && i < last_offset; i += nrpages, addr += nrpages) {
> + for (i = 0; i < last_offset; i += nrpages, addr += nrpages) {
> nrpages = min(last_offset - i, bio_blocks);
>
> /* readahead node pages */
> - nrpages = ra_sum_pages(sbi, pages, addr, nrpages);
> - if (!nrpages)
> - return -ENOMEM;
> + ra_meta_pages(sbi, addr, nrpages, META_POR);
>
> - for (idx = 0; idx < nrpages; idx++) {
> - if (err)
> - goto skip;
> + for (idx = addr; idx < addr + nrpages; idx++) {
> + struct page *page = get_meta_page(sbi, idx);
>
> - lock_page(pages[idx]);
> - if (unlikely(!PageUptodate(pages[idx]))) {
> - err = -EIO;
> - } else {
> - rn = F2FS_NODE(pages[idx]);
> - sum_entry->nid = rn->footer.nid;
> - sum_entry->version = 0;
> - sum_entry->ofs_in_node = 0;
> - sum_entry++;
> - }
> - unlock_page(pages[idx]);
> -skip:
> - page_cache_release(pages[idx]);
> + rn = F2FS_NODE(page);
> + sum_entry->nid = rn->footer.nid;
> + sum_entry->version = 0;
> + sum_entry->ofs_in_node = 0;
> + sum_entry++;
> + f2fs_put_page(page, 1);
> }
>
> - invalidate_mapping_pages(inode->i_mapping, addr,
> - addr + nrpages);
> + truncate_inode_pages_range(META_MAPPING(sbi),
> + addr << PAGE_CACHE_SHIFT,
> + ((addr + nrpages) << PAGE_CACHE_SHIFT) - 1);
> }
> - return err;
> + return 0;
> }
>
> static void remove_nats_in_journal(struct f2fs_sb_info *sbi)
> --
> 2.1.2
>
>
>
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