f2fs: use ra_meta_pages to simplify readahead code in restore_node_summary

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 <[email protected]>

---
 fs/f2fs/node.c | 68 +++++++++++++---------------------------------------------
 1 file changed, 15 insertions(+), 53 deletions(-)

fs/f2fs/node.c +15 -54

index 5aa54a0..ab48b4c 100644
@@ -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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-----Original Message-----
From: Changman Lee [mailto:[email protected]]
Sent: Wednesday, December 17, 2014 11:20 PM
To: Chao Yu
Cc: Jaegeuk Kim; Changman Lee; [email protected]; [email protected]; [email protected]
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 <[email protected]>