f2fs: optimize restore_node_summary slightly

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.fnst@cn.fujitsu.com>
Reviewed-by: Chao Yu <chao2.yu@samsung.com>
[Jaegeuk Kim: modify the flow for better neat code]
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 12c9ded767d93d9cf46495ae593860288bce8508..c415cec041b73f0c573f46b5a6f40f6a3c50e5d4 100644 (file)
--- 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,
@@ -1626,15 +1620,17 @@ int restore_node_summary(struct f2fs_sb_info *sbi,
        addr = START_BLOCK(sbi, segno);
        sum_entry = &sum->entries[0];
 
-       for (i = 0; i < last_offset; i += nrpages, addr += nrpages) {
+       for (i = 0; !err && i < last_offset; i += nrpages, addr += nrpages) {
                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) {
+                       if (err)
+                               goto skip;
 
                        lock_page(page);
                        if (unlikely(!PageUptodate(page))) {
@@ -1646,9 +1642,9 @@ int restore_node_summary(struct f2fs_sb_info *sbi,
                                sum_entry->ofs_in_node = 0;
                                sum_entry++;
                        }
-
-                       list_del(&page->lru);
                        unlock_page(page);
+skip:
+                       list_del(&page->lru);
                        __free_pages(page, 0);
                }
        }

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 199c964680c5e868d4e4de75c80e1026240e82d2..b3f84318b7edd1ca52d7c841ba34f22279399f12 100644 (file)
--- 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;
                        }
                }
        }