Re: [PATCH v4 15/17] xfs: Check for -ENOATTR or -EEXIST

Darrick J. Wong
2019-11-08T21:28:38Z

On Wed, Nov 06, 2019 at 06:27:59PM -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>
> ---
> fs/xfs/libxfs/xfs_attr.c | 25 +++++++++++++++++++++++++
> 1 file changed, 25 insertions(+)
>
> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> index 5dcb19f..626d4a98 100644
> --- a/fs/xfs/libxfs/xfs_attr.c
> +++ b/fs/xfs/libxfs/xfs_attr.c
> @@ -458,6 +458,27 @@ xfs_attr_set(
> goto out_trans_cancel;
>
> xfs_trans_ijoin(args.trans, dp, 0);
> +
> + error = xfs_has_attr(&args);
> + if (error == -EEXIST) {
> + if (name->type & ATTR_CREATE)
> + goto out_trans_cancel;
> + else
> + name->type |= ATTR_REPLACE;
> + }
> +
> + if (error == -ENOATTR && (name->type & ATTR_REPLACE))
> + goto out_trans_cancel;
> +
> + if (name->type & ATTR_REPLACE) {
> + name->type &= ~ATTR_REPLACE;
> + error = xfs_attr_remove_args(&args);
> + if (error)
> + goto out_trans_cancel;
> +
> + name->type |= ATTR_CREATE;

I thought _set_args already handled the remove part of replacing an
attr? And I thought that it did this with an atomic rename? Won't this
break the atomicity of attr replacement?

--D

> + }
> +
> error = xfs_attr_set_args(&args);
> if (error)
> goto out_trans_cancel;
> @@ -543,6 +564,10 @@ xfs_attr_remove(
> */
> xfs_trans_ijoin(args.trans, dp, 0);
>
> + error = xfs_has_attr(&args);
> + if (error == -ENOATTR)
> + goto out;
> +
> error = xfs_attr_remove_args(&args);
> if (error)
> goto out;
> --
> 2.7.4
>