> On Jun 13, 2022, at 7:18 PM, NeilBrown <neilb@xxxxxxx> wrote:
>
> If the filesystem supports it, renames can now be concurrent with other
> updates.
> We use lock_rename_lookup_one() to do the appropriate locking in the
> right order and to look up the names.
>
> Signed-off-by: NeilBrown <neilb@xxxxxxx>
Reviewed-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
> ---
> fs/nfsd/vfs.c | 49 +++++++++++++++++++------------------------------
> 1 file changed, 19 insertions(+), 30 deletions(-)
>
> diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
> index 6cdd5e407600..b0df216ab3e4 100644
> --- a/fs/nfsd/vfs.c
> +++ b/fs/nfsd/vfs.c
> @@ -1584,6 +1584,7 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
> __be32 err;
> int host_err;
> bool close_cached = false;
> + DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
Ditto.
>
> err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_REMOVE);
> if (err)
> @@ -1611,41 +1612,37 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
>
> /* cannot use fh_lock as we need deadlock protective ordering
> * so do it by hand */
> - trap = lock_rename(tdentry, fdentry);
> - ffhp->fh_locked = tfhp->fh_locked = true;
> - fh_fill_pre_attrs(ffhp, true);
> - fh_fill_pre_attrs(tfhp, true);
> -
> - odentry = lookup_one_len(fname, fdentry, flen);
> - host_err = PTR_ERR(odentry);
> - if (IS_ERR(odentry))
> + trap = lock_rename_lookup_one(tdentry, fdentry, &ndentry, &odentry,
> + tname, tlen, fname, flen, 0, 0, &wq);
> + host_err = PTR_ERR(trap);
> + if (IS_ERR(trap))
> goto out_nfserr;
> + ffhp->fh_locked = tfhp->fh_locked = true;
> + fh_fill_pre_attrs(ffhp, (ndentry->d_flags & DCACHE_PAR_UPDATE) == 0);
> + fh_fill_pre_attrs(tfhp, (ndentry->d_flags & DCACHE_PAR_UPDATE) == 0);
>
> host_err = -ENOENT;
> if (d_really_is_negative(odentry))
> - goto out_dput_old;
> + goto out_unlock;
> host_err = -EINVAL;
> if (odentry == trap)
> - goto out_dput_old;
> + goto out_unlock;
>
> - ndentry = lookup_one_len(tname, tdentry, tlen);
> - host_err = PTR_ERR(ndentry);
> - if (IS_ERR(ndentry))
> - goto out_dput_old;
> host_err = -ENOTEMPTY;
> if (ndentry == trap)
> - goto out_dput_new;
> + goto out_unlock;
>
> host_err = -EXDEV;
> if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt)
> - goto out_dput_new;
> + goto out_unlock;
> if (ffhp->fh_export->ex_path.dentry != tfhp->fh_export->ex_path.dentry)
> - goto out_dput_new;
> + goto out_unlock;
>
> if ((ndentry->d_sb->s_export_op->flags & EXPORT_OP_CLOSE_BEFORE_UNLINK) &&
> nfsd_has_cached_files(ndentry)) {
> close_cached = true;
> - goto out_dput_old;
> + dget(ndentry);
> + goto out_unlock;
> } else {
> struct renamedata rd = {
> .old_mnt_userns = &init_user_ns,
> @@ -1662,23 +1659,15 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
> host_err = commit_metadata(ffhp);
> }
> }
> - out_dput_new:
> - dput(ndentry);
> - out_dput_old:
> - dput(odentry);
> - out_nfserr:
> - err = nfserrno(host_err);
> - /*
> - * We cannot rely on fh_unlock on the two filehandles,
> - * as that would do the wrong thing if the two directories
> - * were the same, so again we do it by hand.
> - */
> if (!close_cached) {
> fh_fill_post_attrs(ffhp);
> fh_fill_post_attrs(tfhp);
> }
> - unlock_rename(tdentry, fdentry);
> + out_unlock:
> + unlock_rename_lookup(tdentry, fdentry, ndentry, odentry);
> ffhp->fh_locked = tfhp->fh_locked = false;
> + out_nfserr:
> + err = nfserrno(host_err);
> fh_drop_write(ffhp);
>
> /*
>
>
--
Chuck Lever
