1 files changed, 52 insertions, 23 deletions

diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
index 58c1a0096f7d..4e7d4ceeb084 100644
--- a/fs/f2fs/recovery.c
+++ b/fs/f2fs/recovery.c
@@ -360,21 +360,63 @@ static unsigned int adjust_por_ra_blocks(struct f2fs_sb_info *sbi,
 	return ra_blocks;
 }
 
+/* Detect looped node chain with Floyd's cycle detection algorithm. */
+static int sanity_check_node_chain(struct f2fs_sb_info *sbi, block_t blkaddr,
+		block_t *blkaddr_fast, bool *is_detecting)
+{
+	unsigned int ra_blocks = RECOVERY_MAX_RA_BLOCKS;
+	struct page *page = NULL;
+	int i;
+
+	if (!*is_detecting)
+		return 0;
+
+	for (i = 0; i < 2; i++) {
+		if (!f2fs_is_valid_blkaddr(sbi, *blkaddr_fast, META_POR)) {
+			*is_detecting = false;
+			return 0;
+		}
+
+		page = f2fs_get_tmp_page(sbi, *blkaddr_fast);
+		if (IS_ERR(page))
+			return PTR_ERR(page);
+
+		if (!is_recoverable_dnode(page)) {
+			f2fs_put_page(page, 1);
+			*is_detecting = false;
+			return 0;
+		}
+
+		ra_blocks = adjust_por_ra_blocks(sbi, ra_blocks, *blkaddr_fast,
+						next_blkaddr_of_node(page));
+
+		*blkaddr_fast = next_blkaddr_of_node(page);
+		f2fs_put_page(page, 1);
+
+		f2fs_ra_meta_pages_cond(sbi, *blkaddr_fast, ra_blocks);
+	}
+
+	if (*blkaddr_fast == blkaddr) {
+		f2fs_notice(sbi, "%s: Detect looped node chain on blkaddr:%u."
+				" Run fsck to fix it.", __func__, blkaddr);
+		return -EINVAL;
+	}
+	return 0;
+}
+
 static int find_fsync_dnodes(struct f2fs_sb_info *sbi, struct list_head *head,
 				bool check_only)
 {
 	struct curseg_info *curseg;
 	struct page *page = NULL;
-	block_t blkaddr;
-	unsigned int loop_cnt = 0;
-	unsigned int ra_blocks = RECOVERY_MAX_RA_BLOCKS;
-	unsigned int free_blocks = MAIN_SEGS(sbi) * sbi->blocks_per_seg -
-						valid_user_blocks(sbi);
+	block_t blkaddr, blkaddr_fast;
+	bool is_detecting = true;
 	int err = 0;
 
 	/* get node pages in the current segment */
 	curseg = CURSEG_I(sbi, CURSEG_WARM_NODE);
 	blkaddr = NEXT_FREE_BLKADDR(sbi, curseg);
+	blkaddr_fast = blkaddr;
 
 	while (1) {
 		struct fsync_inode_entry *entry;
@@ -418,10 +460,8 @@ static int find_fsync_dnodes(struct f2fs_sb_info *sbi, struct list_head *head,
 								quota_inode);
 			if (IS_ERR(entry)) {
 				err = PTR_ERR(entry);
-				if (err == -ENOENT) {
-					err = 0;
+				if (err == -ENOENT)
 					goto next;
-				}
 				f2fs_put_page(page, 1);
 				break;
 			}
@@ -431,25 +471,14 @@ static int find_fsync_dnodes(struct f2fs_sb_info *sbi, struct list_head *head,
 		if (IS_INODE(page) && is_dent_dnode(page))
 			entry->last_dentry = blkaddr;
 next:
-		/* sanity check in order to detect looped node chain */
-		if (++loop_cnt >= free_blocks ||
-			blkaddr == next_blkaddr_of_node(page)) {
-			f2fs_notice(sbi, "%s: detect looped node chain, blkaddr:%u, next:%u",
-				    __func__, blkaddr,
-				    next_blkaddr_of_node(page));
-			f2fs_put_page(page, 1);
-			err = -EINVAL;
-			break;
-		}
-
-		ra_blocks = adjust_por_ra_blocks(sbi, ra_blocks, blkaddr,
-						next_blkaddr_of_node(page));
-
 		/* check next segment */
 		blkaddr = next_blkaddr_of_node(page);
 		f2fs_put_page(page, 1);
 
-		f2fs_ra_meta_pages_cond(sbi, blkaddr, ra_blocks);
+		err = sanity_check_node_chain(sbi, blkaddr, &blkaddr_fast,
+				&is_detecting);
+		if (err)
+			break;
 	}
 	return err;
 }