Re: [PATCH v7 04/19] xfs: Check for -ENOATTR or -EEXIST

Brian Foster
2020-02-24T13:08:18Z

On Sat, Feb 22, 2020 at 07:05:56PM -0700, Allison Collins wrote:
> Delayed operations cannot return error codes. So we must check for these conditions
> first before starting set or remove operations
>
> Signed-off-by: Allison Collins <allison.henderson@oracle.com>
> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---
> fs/xfs/libxfs/xfs_attr.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> index 2255060..a2f812f 100644
> --- a/fs/xfs/libxfs/xfs_attr.c
> +++ b/fs/xfs/libxfs/xfs_attr.c
> @@ -437,6 +437,14 @@ xfs_attr_set(
> goto out_trans_cancel;
>
> xfs_trans_ijoin(args.trans, dp, 0);
> +
> + error = xfs_has_attr(&args);
> + if (error == -EEXIST && (name->type & ATTR_CREATE))
> + goto out_trans_cancel;
> +
> + if (error == -ENOATTR && (name->type & ATTR_REPLACE))
> + goto out_trans_cancel;
> +

So xfs_has_attr() calls the format-specific variant for the attr fork.
If it's node format, xfs_attr_node_hasname() allocs a state and only
frees it if the lookup happens to fail. That looks like a potential
memory leak... Perhaps that helper should free the state in any case the
caller doesn't ask for a pointer?

Brian

> error = xfs_attr_set_args(&args);
> if (error)
> goto out_trans_cancel;
> @@ -525,6 +533,10 @@ xfs_attr_remove(
> */
> xfs_trans_ijoin(args.trans, dp, 0);
>
> + error = xfs_has_attr(&args);
> + if (error != -EEXIST)
> + goto out;
> +
> error = xfs_attr_remove_args(&args);
> if (error)
> goto out;
> --
> 2.7.4
>