Re: [PATCH v2 2/4] ext4: skip cursor node in ext4_orphan_del()

["Darrick J. Wong" <djwong@kernel.org>]

On Wed, Apr 15, 2026 at 06:55:03PM +0800, Ye Bin wrote:
> From: Ye Bin <yebin10@huawei.com>
> 
> This patch is prepared for displaying orphan_list information. Because
> temporary nodes may be inserted when the orphan_list is traversed and
> displayed, these temporary nodes need to be skipped.
> 
> Signed-off-by: Ye Bin <yebin10@huawei.com>
> ---
>  fs/ext4/orphan.c | 20 +++++++++++++++++++-
>  1 file changed, 19 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/ext4/orphan.c b/fs/ext4/orphan.c
> index f7e7f77e021e..a6bffe67ef75 100644
> --- a/fs/ext4/orphan.c
> +++ b/fs/ext4/orphan.c
> @@ -220,6 +220,23 @@ static int ext4_orphan_file_del(handle_t *handle, struct inode *inode)
>  	return ret;
>  }
>  
> +static inline bool ext4_is_cursor(struct inode *inode)
> +{
> +	return (inode->i_ino == 0);
> +}
> +
> +static inline struct list_head *ext4_orphan_prev_node(
> +					struct ext4_inode_info *pos,
> +					struct list_head *head)
> +{
> +	list_for_each_entry_continue_reverse(pos, head, i_orphan) {
> +		if (likely(!ext4_is_cursor(&pos->vfs_inode)))
> +			return &pos->i_orphan;
> +	}
> +
> +	return head;

Waitaminute, you inject the procfs file's cursor into the orphan list
with a phony ext4_inode_info??  That sounds like a landmine waiting to
go off the next time someone writes code that traverses the list, or
even wants to check that its non-empty.

--D

> +}
> +
>  /*
>   * ext4_orphan_del() removes an unlinked or truncated inode from the list
>   * of such inodes stored on disk, because it is finally being cleaned up.
> @@ -253,7 +270,8 @@ int ext4_orphan_del(handle_t *handle, struct inode *inode)
>  	mutex_lock(&sbi->s_orphan_lock);
>  	ext4_debug("remove inode %llu from orphan list\n", inode->i_ino);
>  
> -	prev = ei->i_orphan.prev;
> +	prev = ext4_orphan_prev_node(ei, &sbi->s_orphan);
> +
>  	list_del_init(&ei->i_orphan);
>  
>  	/* If we're on an error path, we may not have a valid
> -- 
> 2.34.1
> 
>