[f2fs-dev][PATCH v2] f2fs: use ra_meta_pages to simplify readahead code in restore_node_summary

[f2fs-dev][PATCH v2] f2fs: use ra_meta_pages to simplify readahead code in restore_node_summary

[Chao Yu]

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@samsung.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

Re: [f2fs-dev] [PATCH v2] f2fs: use ra_meta_pages to simplify readahead code in restore_node_summary

[Changman Lee]

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@samsung.com>

2014-12-17 19:10 GMT+09:00 Chao Yu <chao2.yu@samsung.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@samsung.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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RE: [f2fs-dev] [PATCH v2] f2fs: use ra_meta_pages to simplify readahead code in restore_node_summary

[Chao Yu]

Hi Changman,

> -----Original Message-----
> From: Changman Lee [mailto:cm224.lee@gmail.com]
> Sent: Wednesday, December 17, 2014 11:20 PM
> To: Chao Yu
> Cc: Jaegeuk Kim; Changman Lee; linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org;
> linux-f2fs-devel@lists.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.

I think you're right, I use truncate_inode_pages_range because just following the
usage of readahead-invalidate pair in recovery flow, but without considering the
difference between them.

I will fix this as you suggested.

> 
> Thanks,
> 
> Reviewed-by: Changman Lee <cm224.lee@samsung.com>

And thanks for your review! :)

Regards,
Yu