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Commit fb0e72c8 authored by Chao Yu's avatar Chao Yu Committed by Jaegeuk Kim
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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: default avatarYunlei He <heyunlei@huawei.com>
Signed-off-by: default avatarChao Yu <yuchao0@huawei.com>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent 0f9ec2a8

fs/f2fs/recovery.c

+14 −0
Original line number Diff line number Diff line
@@ -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);