[Ocfs2-devel] [PATCH] ocfs2: the parent directory reference count should be increased only after the ocfs2_add_entry function is successfully called

[Joseph Qi]

On 2020/3/16 00:59, wangjian wrote:
> Under some conditions, the directory cannot be deleted.
> The specific scenarios are as follows: (for example,
> /mnt/ocfs2 is the mount point)
> 
> 1. Create the /mnt/ocfs2/p_dir directory. At this time,
> the i_nlink corresponding to the inode of
> the /mnt/ocfs2/p_dir directory is equal to 2.
> 
> 2. During the process of creating the
> /mnt/ocfs2/p_dir/s_dir directory, if the call to the inc_nlink
> function in ocfs2_mknod succeeds, the functions such as
> ocfs2_init_acl, ocfs2_init_security_set, and ocfs2_dentry_attach_lock fail.
> At this time, the i_nlink corresponding to the inode of the
> /mnt/ocfs2/p_dir directory is equal to 3, but /mnt/ocfs2/p_dir/s_dir
> is not added to the /mnt/ocfs2/p_dir directory entry.
> 
> 3. Delete the /mnt/ocfs2/p_dir directory (rm -rf /mnt/ocfs2/p_dir).
> At this time, it is found that the i_nlink corresponding to
> the inode corresponding to the /mnt/ocfs2/p_dir directory is equal to 3.
> Therefore, the /mnt/ocfs2/p_dir directory cannot be deleted.
> 
> Signed-off-by: Jian wang <wangjian161 at huawei.com>
> ---
>  ocfs2/namei.c | 24 +++++++++++++-----------
>  1 file changed, 13 insertions(+), 11 deletions(-)
> 
> diff --git a/ocfs2/namei.c b/ocfs2/namei.c
> index 8ea51cf..19543b4 100644
> --- a/ocfs2/namei.c
> +++ b/ocfs2/namei.c
> @@ -388,17 +388,6 @@ static int ocfs2_mknod(struct inode *dir,
>              mlog_errno(status);
>              goto leave;
>          }
> -
> -        status = ocfs2_journal_access_di(handle, INODE_CACHE(dir),
> -                         parent_fe_bh,
> -                         OCFS2_JOURNAL_ACCESS_WRITE);
> -        if (status < 0) {
> -            mlog_errno(status);
> -            goto leave;
> -        }

We can't simply move it down since we should get journal access before
modification.

Thanks,
Joseph 

> -        ocfs2_add_links_count(dirfe, 1);
> -        ocfs2_journal_dirty(handle, parent_fe_bh);
> -        inc_nlink(dir);
>      }
>  
>      status = ocfs2_init_acl(handle, inode, dir, new_fe_bh, parent_fe_bh,
> @@ -440,6 +429,19 @@ static int ocfs2_mknod(struct inode *dir,
>          goto leave;
>      }
>  
> +    if (S_ISDIR(mode)) {
> +        status = ocfs2_journal_access_di(handle, INODE_CACHE(dir),
> +                         parent_fe_bh,
> +                         OCFS2_JOURNAL_ACCESS_WRITE);
> +        if (status < 0) {
> +            mlog_errno(status);
> +            goto leave;
> +        }
> +        ocfs2_add_links_count(dirfe, 1);
> +        ocfs2_journal_dirty(handle, parent_fe_bh);
> +        inc_nlink(dir);
> +    }
> +
>      insert_inode_hash(inode);
>      d_instantiate(dentry, inode);
>      status = 0;