Re: [PATCH] f2fs: check segment type before recover data

From: Chao Yu
Date: Tue Jan 02 2018 - 01:50:09 EST


On 2017/12/30 15:42, Yunlong Song wrote:
> In some case, the node blocks has wrong blkaddr whose segment type is

You mean *data block* has wrong blkaddr whose segment type is NODE?

> NODE, e.g., recover inode has missing xattr flag and the blkaddr is in
> the xattr range. Since fsck.f2fs does not check the recovery nodes, this
> will cause __f2fs_replace_block change the curseg of node and do the
> update_sit_entry(sbi, new_blkaddr, 1) with no next_blkoff refresh, as a

Do you mean the root cause is that __f2fs_replace_block didn't update
next_blkoff?

> result, when recovery process write checkpoint and sync nodes, the
> next_blkoff of curseg is used in the segment bit map, then it will
> cause f2fs_bug_on. So let's check the segment type before recover data,
> and stop recover if it is not in DATA segment.

Sorry, I can't catch the whole cause and effect from you description, if
possible, could you give an example?

Thanks,

>
> Signed-off-by: Yunlong Song <yunlong.song@xxxxxxxxxx>
> ---
> fs/f2fs/recovery.c | 3 ++-
> fs/f2fs/segment.h | 3 +++
> 2 files changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
> index 7d63faf..e8fee4a 100644
> --- a/fs/f2fs/recovery.c
> +++ b/fs/f2fs/recovery.c
> @@ -478,7 +478,8 @@ static int do_recover_data(struct f2fs_sb_info *sbi, struct inode *inode,
> }
>
> /* dest is valid block, try to recover from src to dest */
> - if (is_valid_blkaddr(sbi, dest, META_POR)) {
> + if (is_valid_blkaddr(sbi, dest, META_POR) &&
> + is_data_blkaddr(sbi, dest)) {
>
> if (src == NULL_ADDR) {
> err = reserve_new_block(&dn);
> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
> index 71a2aaa..5c5a215 100644
> --- a/fs/f2fs/segment.h
> +++ b/fs/f2fs/segment.h
> @@ -115,6 +115,9 @@
> #define SECTOR_TO_BLOCK(sectors) \
> ((sectors) >> F2FS_LOG_SECTORS_PER_BLOCK)
>
> +#define is_data_blkaddr(sbi, blkaddr) \
> + (IS_DATASEG(get_seg_entry(sbi, GET_SEGNO(sbi, blkaddr))->type))
> +
> /*
> * indicate a block allocation direction: RIGHT and LEFT.
> * RIGHT means allocating new sections towards the end of volume.
>