On Thu, Nov 28, 2019 at 01:56:43PM +1100, NeilBrown wrote:
>
> vfs_rmdir and vfs_unlink can return -EBUSY if the
> target is a mountpoint. This currently gets passed to
> nfserrno() by nfsd_unlink(), and that results in a WARNing,
> which is not user-friendly.
>
> Possibly the best NFSv4 error is NFS4ERR_FILE_OPEN, because
> there is a sense in which the object is currently in use
> by some other task. The Linux NFSv4 client will map this
> back to EBUSY, which is an added benefit.
>
> For NFSv3, the best we can do is probably NFS3ERR_ACCES, which isn't
> true, but is not less true than the other options.
Makes sense to me, thanks.--b.
>
> Signed-off-by: NeilBrown <neilb@xxxxxxx>
> ---
> fs/nfsd/nfsd.h | 3 ++-
> fs/nfsd/vfs.c | 12 +++++++++++-
> 2 files changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
> index af2947551e9c..57b93d95fa5c 100644
> --- a/fs/nfsd/nfsd.h
> +++ b/fs/nfsd/nfsd.h
> @@ -280,7 +280,8 @@ void nfsd_lockd_shutdown(void);
> #define nfserr_union_notsupp cpu_to_be32(NFS4ERR_UNION_NOTSUPP)
> #define nfserr_offload_denied cpu_to_be32(NFS4ERR_OFFLOAD_DENIED)
> #define nfserr_wrong_lfs cpu_to_be32(NFS4ERR_WRONG_LFS)
> -#define nfserr_badlabel cpu_to_be32(NFS4ERR_BADLABEL)
> +#define nfserr_badlabel cpu_to_be32(NFS4ERR_BADLABEL)
> +#define nfserr_file_open cpu_to_be32(NFS4ERR_FILE_OPEN)
>
> /* error codes for internal use */
> /* if a request fails due to kmalloc failure, it gets dropped.
> diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
> index bd0a385df3fc..fa2acb6a3b5c 100644
> --- a/fs/nfsd/vfs.c
> +++ b/fs/nfsd/vfs.c
> @@ -1809,7 +1809,17 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
> out_drop_write:
> fh_drop_write(fhp);
> out_nfserr:
> - err = nfserrno(host_err);
> + if (host_err == -EBUSY) {
> + /* name is mounted-on. There is no perfect
> + * error status.
> + */
> + if (nfsd_v4client(rqstp))
> + err = nfserr_file_open;
> + else
> + err = nfserr_acces;
> + } else {
> + err = nfserrno(host_err);
> + }
> out:
> return err;
> }
> --
> 2.24.0
>
