Re: [PATCH v8 7/9] NFSD handle OFFLOAD_CANCEL op

[Anna Schumaker <schumaker.anna@gmail.com>]

Hi Olga,

On 04/13/2018 01:01 PM, Olga Kornievskaia wrote:
> Upon receiving OFFLOAD_CANCEL search the list of copy stateids,
> if found then set the SIGPENDING signal so that do_splice stops
> copying and also send kthread_stop to the copy thread to stop
> and wait for it. Take a reference on the copy from the
> offload_cancel thread so that it won't go away while we are
> trying to process it.
> 
> Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
> ---
>  fs/nfsd/nfs4proc.c | 40 +++++++++++++++++++++++++++++++++++++---
>  fs/nfsd/state.h    |  1 +
>  fs/nfsd/xdr4.h     |  1 +
>  3 files changed, 39 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
> index 9d5f0d0..cebc087 100644
> --- a/fs/nfsd/nfs4proc.c
> +++ b/fs/nfsd/nfs4proc.c
> @@ -1100,11 +1100,19 @@ static int fill_in_write_vector(struct kvec *vec, struct nfsd4_write *write)
>  out:
>  	return status;
>  }
> +
> +void nfs4_put_copy(struct nfsd4_copy *copy)
> +{
> +	if (!refcount_dec_and_test(&copy->refcount))
> +		return;
> +	kfree(copy);
> +}
> +
>  static void nfsd4_cb_offload_release(struct nfsd4_callback *cb)
>  {
>  	struct nfsd4_copy *copy = container_of(cb, struct nfsd4_copy, cp_cb);
>  
> -	kfree(copy);
> +	nfs4_put_copy(copy);
>  }
>  
>  static int nfsd4_cb_offload_done(struct nfsd4_callback *cb,
> @@ -1135,6 +1143,8 @@ static ssize_t _nfsd_copy_file_range(struct nfsd4_copy *copy)
>  	u64 dst_pos = copy->cp_dst_pos;
>  
>  	do {
> +		if (signalled() || kthread_should_stop())
> +			break;
>  		bytes_copied = nfsd_copy_file_range(copy->file_src, src_pos,
>  				copy->file_dst, dst_pos, bytes_total);
>  		if (bytes_copied <= 0)
> @@ -1188,7 +1198,7 @@ static void cleanup_async_copy(struct nfsd4_copy *copy)
>  	spin_lock(&copy->cp_clp->async_lock);
>  	list_del(&copy->copies);
>  	spin_unlock(&copy->cp_clp->async_lock);
> -	kfree(copy);
> +	nfs4_put_copy(copy);
>  }
>  
>  static int nfsd4_do_async_copy(void *data)
> @@ -1238,6 +1248,7 @@ static int nfsd4_do_async_copy(void *data)
>  			goto out;
>  		if (!nfs4_init_cp_state(nn, copy))
>  			goto out;
> +		refcount_set(&async_copy->refcount, 1);
>  		memcpy(&copy->cp_res.cb_stateid, &copy->cp_stateid,
>  			sizeof(copy->cp_stateid));
>  		dup_copy_fields(copy, async_copy);
> @@ -1266,7 +1277,30 @@ static int nfsd4_do_async_copy(void *data)
>  		     struct nfsd4_compound_state *cstate,
>  		     union nfsd4_op_u *u)
>  {
> -	return 0;
> +	struct nfsd4_offload_status *os = &u->offload_status;
> +	__be32 status = 0;
> +	struct nfsd4_copy *copy;
> +	bool found = false;
> +	struct nfs4_client *clp = cstate->clp;
> +
> +	spin_lock(&clp->async_lock);
> +	list_for_each_entry(copy, &clp->async_copies, copies) {
> +		if (memcmp(&copy->cps->cp_stateid, &os->stateid,
> +				NFS4_STATEID_SIZE))

I'm having trouble compiling this patch:  

fs/nfsd/nfs4proc.c: In function 'nfsd4_offload_cancel':
fs/nfsd/nfs4proc.c:1288:21: error: 'struct nfsd4_copy' has no member named 'cps'; did you mean 'cp_res'?
   if (memcmp(&copy->cps->cp_stateid, &os->stateid,
                     ^~~
                     cp_res

Is something out of order here?

Anna

> +			continue;
> +		found = true;
> +		refcount_inc(&copy->refcount);
> +		break;
> +	}
> +	spin_unlock(&clp->async_lock);
> +	if (found) {
> +		set_tsk_thread_flag(copy->copy_task, TIF_SIGPENDING);
> +		kthread_stop(copy->copy_task);
> +		nfs4_put_copy(copy);
> +	} else
> +		status = nfserr_bad_stateid;
> +
> +	return status;
>  }
>  
>  static __be32
> diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
> index d8893427..0ee2ed3 100644
> --- a/fs/nfsd/state.h
> +++ b/fs/nfsd/state.h
> @@ -641,6 +641,7 @@ extern struct nfs4_client_reclaim *nfs4_client_to_reclaim(const char *name,
>  
>  struct nfs4_file *find_file(struct knfsd_fh *fh);
>  void put_nfs4_file(struct nfs4_file *fi);
> +extern void nfs4_put_copy(struct nfsd4_copy *copy);
>  static inline void get_nfs4_file(struct nfs4_file *fi)
>  {
>  	refcount_inc(&fi->fi_ref);
> diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
> index 5af9eae..249d883 100644
> --- a/fs/nfsd/xdr4.h
> +++ b/fs/nfsd/xdr4.h
> @@ -542,6 +542,7 @@ struct nfsd4_copy {
>  
>  	struct list_head	copies;
>  	struct task_struct	*copy_task;
> +	refcount_t		refcount;
>  };
>  
>  struct nfsd4_seek {
>