On 02/12, Chao Yu wrote:
> From: Leo Stone <leocst...@gmail.com>
>
> The syzbot reproducer mounts a f2fs image, then tries to unlink an
> existing file. However, the unlinked file already has a link count of 0
> when it is read for the first time in do_read_inode().
>
> Add a check to sanity_check_inode() for i_nlink == 0.
>
> [Chao Yu: rebase the code and fix orphan inode recovery issue]
> Reported-by: syzbot+b01a36acd7007e273...@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=b01a36acd7007e273a83
> Fixes: 39a53e0ce0df ("f2fs: add superblock and major in-memory structure")
> Signed-off-by: Leo Stone <leocst...@gmail.com>
> Signed-off-by: Chao Yu <c...@kernel.org>
> ---
> fs/f2fs/checkpoint.c | 4 ++++
> fs/f2fs/f2fs.h | 1 +
> fs/f2fs/inode.c | 6 ++++++
> 3 files changed, 11 insertions(+)
>
> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
> index bd890738b94d..ada2c548645c 100644
> --- a/fs/f2fs/checkpoint.c
> +++ b/fs/f2fs/checkpoint.c
> @@ -751,6 +751,8 @@ int f2fs_recover_orphan_inodes(struct f2fs_sb_info *sbi)
> if (is_sbi_flag_set(sbi, SBI_IS_WRITABLE))
> f2fs_info(sbi, "orphan cleanup on readonly fs");
>
> + set_sbi_flag(sbi, SBI_ORPHAN_RECOVERY);
What about using SBI_POR_DOING?
> +
> start_blk = __start_cp_addr(sbi) + 1 + __cp_payload(sbi);
> orphan_blocks = __start_sum_addr(sbi) - 1 - __cp_payload(sbi);
>
> @@ -778,9 +780,11 @@ int f2fs_recover_orphan_inodes(struct f2fs_sb_info *sbi)
> }
> f2fs_put_page(page, 1);
> }
> +
> /* clear Orphan Flag */
> clear_ckpt_flags(sbi, CP_ORPHAN_PRESENT_FLAG);
> out:
> + clear_sbi_flag(sbi, SBI_ORPHAN_RECOVERY);
> set_sbi_flag(sbi, SBI_IS_RECOVERED);
>
> return err;
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 05879c6dc4d6..1c75081c0c14 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -1322,6 +1322,7 @@ enum {
> SBI_IS_CLOSE, /* specify unmounting */
> SBI_NEED_FSCK, /* need fsck.f2fs to fix */
> SBI_POR_DOING, /* recovery is doing or not */
> + SBI_ORPHAN_RECOVERY, /* orphan inodes recovery is
> doing */
> SBI_NEED_SB_WRITE, /* need to recover superblock */
> SBI_NEED_CP, /* need to checkpoint */
> SBI_IS_SHUTDOWN, /* shutdown by ioctl */
> diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
> index d6ad7810df69..02f1b69d03d8 100644
> --- a/fs/f2fs/inode.c
> +++ b/fs/f2fs/inode.c
> @@ -386,6 +386,12 @@ static bool sanity_check_inode(struct inode *inode,
> struct page *node_page)
> }
> }
>
> + if (inode->i_nlink == 0 && !is_sbi_flag_set(sbi, SBI_ORPHAN_RECOVERY)) {
> + f2fs_warn(sbi, "%s: inode (ino=%lx) has a link count of 0",
> + __func__, inode->i_ino);
> + return false;
> + }
> +
> return true;
> }
>
> --
> 2.48.1.502.g6dc24dfdaf-goog
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