From fb0e72c8b94903be3a7e742ab0a4b53b89e7ee35 Mon Sep 17 00:00:00 2001 From: Chao Yu Date: Sat, 3 Feb 2018 17:44:39 +0800 Subject: [PATCH] f2fs: fix to handle looped node chain during recovery There is no checksum in node block now, so bit-transition from hardware can make node_footer.next_blkaddr being corrupted w/o any detection, result in node chain becoming looped one. For this condition, during recovery, in order to avoid running into dead loop, let's detect it and just skip out. Signed-off-by: Yunlei He Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim --- fs/f2fs/recovery.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c index c5e5c45..1b23d3f 100644 --- a/fs/f2fs/recovery.c +++ b/fs/f2fs/recovery.c @@ -242,6 +242,9 @@ static int find_fsync_dnodes(struct f2fs_sb_info *sbi, struct list_head *head, struct curseg_info *curseg; struct page *page = NULL; block_t blkaddr; + unsigned int loop_cnt = 0; + unsigned int free_blocks = sbi->user_block_count - + valid_user_blocks(sbi); int err = 0; /* get node pages in the current segment */ @@ -294,6 +297,17 @@ 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_msg(sbi->sb, KERN_NOTICE, + "%s: detect looped node chain, " + "blkaddr:%u, next:%u", + __func__, blkaddr, next_blkaddr_of_node(page)); + err = -EINVAL; + break; + } + /* check next segment */ blkaddr = next_blkaddr_of_node(page); f2fs_put_page(page, 1); -- 2.7.4