[Ocfs2-devel] [PATCH v5] ocfs2: roll back the reference count modification of the parent directory if an error occurs

[Joseph Qi]

On 2020/3/17 20:28, 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>

Reviewed-by: Joseph Qi <joseph.qi at linux.alibaba.com>
> ---
>  ocfs2/namei.c | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/ocfs2/namei.c b/ocfs2/namei.c
> index 8ea51cf..eaecab1 100644
> --- a/ocfs2/namei.c
> +++ b/ocfs2/namei.c
> @@ -406,7 +406,7 @@ static int ocfs2_mknod(struct inode *dir,
>  
>      if (status < 0) {
>          mlog_errno(status);
> -        goto leave;
> +        goto roll_back;
>      }
>  
>      if (si.enable) {
> @@ -414,7 +414,7 @@ static int ocfs2_mknod(struct inode *dir,
>                           meta_ac, data_ac);
>          if (status < 0) {
>              mlog_errno(status);
> -            goto leave;
> +            goto roll_back;
>          }
>      }
>  
> @@ -427,7 +427,7 @@ static int ocfs2_mknod(struct inode *dir,
>                        OCFS2_I(dir)->ip_blkno);
>      if (status) {
>          mlog_errno(status);
> -        goto leave;
> +        goto roll_back;
>      }
>  
>      dl = dentry->d_fsdata;
> @@ -437,12 +437,19 @@ static int ocfs2_mknod(struct inode *dir,
>                   &lookup);
>      if (status < 0) {
>          mlog_errno(status);
> -        goto leave;
> +        goto roll_back;
>      }
>  
>      insert_inode_hash(inode);
>      d_instantiate(dentry, inode);
>      status = 0;
> +
> +roll_back:
> +    if (status < 0 && S_ISDIR(mode)) {
> +        ocfs2_add_links_count(dirfe, -1);
> +        drop_nlink(dir);
> +    }
> +
>  leave:
>      if (status < 0 && did_quota_inode)
>          dquot_free_inode(inode);