Re: [PATCH v4 07/12] NFS add support for asynchronous COPY

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

Hi Olga,

On 09/28/2017 01:28 PM, Olga Kornievskaia wrote:
> Change xdr to always send COPY asynchronously.
> 
> Keep the list copies send in a list under a server structure.
> Once copy is sent, it waits on a completion structure that will
> be signalled by the callback thread that receives CB_OFFLOAD.
> 
> Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
> ---
>  fs/nfs/callback_proc.c    | 38 ++++++++++++++++++++++++++++++-
>  fs/nfs/client.c           |  1 +
>  fs/nfs/nfs42proc.c        | 57 ++++++++++++++++++++++++++++++++++++++++++-----
>  fs/nfs/nfs42xdr.c         |  8 ++++---
>  include/linux/nfs_fs.h    |  9 ++++++++
>  include/linux/nfs_fs_sb.h |  1 +
>  include/linux/nfs_xdr.h   |  1 +
>  7 files changed, 106 insertions(+), 9 deletions(-)
> 
> diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
> index eef2728..d3e7b61 100644
> --- a/fs/nfs/callback_proc.c
> +++ b/fs/nfs/callback_proc.c
> @@ -657,9 +657,45 @@ __be32 nfs4_callback_notify_lock(void *argp, void *resp,
>  }
>  #endif /* CONFIG_NFS_V4_1 */
>  #ifdef CONFIG_NFS_V4_2
> -__be32 nfs4_callback_offload(void *args, void *dummy,
> +static void nfs4_copy_cb_args(struct nfs4_copy_state *cp_state,
> +				struct cb_offloadargs *args)
> +{
> +	cp_state->count = args->wr_count;
> +	cp_state->error = args->error;
> +	if (!args->error) {
> +		cp_state->verf.committed = args->wr_writeverf.committed;
> +		memcpy(&cp_state->verf.verifier.data[0],
> +			&args->wr_writeverf.verifier.data[0],
> +			NFS4_VERIFIER_SIZE);
> +	}
> +}
> +
> +__be32 nfs4_callback_offload(void *data, void *dummy,
>  			     struct cb_process_state *cps)
>  {
> +	struct cb_offloadargs *args = data;
> +	struct nfs_server *server;
> +	struct nfs4_copy_state *copy;
> +
> +	rcu_read_lock();
> +	list_for_each_entry_rcu(server, &cps->clp->cl_superblocks,
> +				client_link) {
> +		spin_lock(&server->nfs_client->cl_lock);
> +		list_for_each_entry(copy, &server->ss_copies, copies) {
> +			if (memcmp(args->coa_stateid.other,
> +					copy->stateid.other,
> +					sizeof(args->coa_stateid.other)))
> +				continue;
> +			nfs4_copy_cb_args(copy, args);
> +			complete(&copy->completion);
> +			spin_unlock(&server->nfs_client->cl_lock);
> +			goto out;
> +		}
> +		spin_unlock(&server->nfs_client->cl_lock);
> +	}
> +out:
> +	rcu_read_unlock();
> +
>  	return 0;
>  }
>  #endif /* CONFIG_NFS_V4_2 */
> diff --git a/fs/nfs/client.c b/fs/nfs/client.c
> index efebe6c..7b338be 100644
> --- a/fs/nfs/client.c
> +++ b/fs/nfs/client.c
> @@ -876,6 +876,7 @@ struct nfs_server *nfs_alloc_server(void)
>  	INIT_LIST_HEAD(&server->delegations);
>  	INIT_LIST_HEAD(&server->layouts);
>  	INIT_LIST_HEAD(&server->state_owners_lru);
> +	INIT_LIST_HEAD(&server->ss_copies);
>  
>  	atomic_set(&server->active, 0);
>  
> diff --git a/fs/nfs/nfs42proc.c b/fs/nfs/nfs42proc.c
> index 5c42e71..c8ca353 100644
> --- a/fs/nfs/nfs42proc.c
> +++ b/fs/nfs/nfs42proc.c
> @@ -129,6 +129,39 @@ int nfs42_proc_deallocate(struct file *filep, loff_t offset, loff_t len)
>  	return err;
>  }
>  
> +static int handle_async_copy(struct nfs42_copy_res *res,
> +			     struct nfs_server *server,
> +			     struct file *src,
> +			     struct file *dst,
> +			     nfs4_stateid *src_stateid,
> +			     uint64_t *ret_count)
> +{
> +	struct nfs4_copy_state *copy;
> +	int status;> +
> +	copy = kzalloc(sizeof(struct nfs4_copy_state), GFP_NOFS);
> +	if (!copy)
> +		return -ENOMEM;
> +	memcpy(&copy->stateid, &res->write_res.stateid, NFS4_STATEID_SIZE);
> +	init_completion(&copy->completion);
> +
> +	spin_lock(&server->nfs_client->cl_lock);
> +	list_add_tail(&copy->copies, &server->ss_copies);
> +	spin_unlock(&server->nfs_client->cl_lock);
> +
> +	wait_for_completion_interruptible(&copy->completion);
> +	spin_lock(&server->nfs_client->cl_lock);
> +	list_del_init(&copy->copies);
> +	spin_unlock(&server->nfs_client->cl_lock);
> +	*ret_count = copy->count;
> +	memcpy(&res->write_res.verifier, &copy->verf, sizeof(copy->verf));
> +	if (copy->count <= 0)
> +		status = -copy->error;

If copy->count > 0 then status won't be set before this function returns.  GCC complains about this when I try compiling.

Anna

> +
> +	kfree(copy);
> +	return status;
> +}
> +
>  static ssize_t _nfs42_proc_copy(struct file *src,
>  				struct nfs_lock_context *src_lock,
>  				struct file *dst,
> @@ -167,9 +200,13 @@ static ssize_t _nfs42_proc_copy(struct file *src,
>  	if (status)
>  		return status;
>  
> -	res->commit_res.verf = kzalloc(sizeof(struct nfs_writeverf), GFP_NOFS);
> -	if (!res->commit_res.verf)
> -		return -ENOMEM;
> +	res->commit_res.verf = NULL;
> +	if (args->sync) {
> +		res->commit_res.verf =
> +			kzalloc(sizeof(struct nfs_writeverf), GFP_NOFS);
> +		if (!res->commit_res.verf)
> +			return -ENOMEM;
> +	}
>  	status = nfs4_call_sync(server->client, server, &msg,
>  				&args->seq_args, &res->seq_res, 0);
>  	if (status == -ENOTSUPP)
> @@ -177,18 +214,27 @@ static ssize_t _nfs42_proc_copy(struct file *src,
>  	if (status)
>  		goto out;
>  
> -	if (nfs_write_verifier_cmp(&res->write_res.verifier.verifier,
> +	if (args->sync &&
> +		!nfs_write_verifier_cmp(&res->write_res.verifier.verifier,
>  				    &res->commit_res.verf->verifier)) {
>  		status = -EAGAIN;
>  		goto out;
>  	}
>  
> +	if (!res->synchronous) {
> +		status = handle_async_copy(res, server, src, dst,
> +				&args->src_stateid, &res->write_res.count);
> +		if (status)
> +			return status;
> +	}
> +
>  	truncate_pagecache_range(dst_inode, pos_dst,
>  				 pos_dst + res->write_res.count);
>  
>  	status = res->write_res.count;
>  out:
> -	kfree(res->commit_res.verf);
> +	if (args->sync)
> +		kfree(res->commit_res.verf);
>  	return status;
>  }
>  
> @@ -205,6 +251,7 @@ ssize_t nfs42_proc_copy(struct file *src, loff_t pos_src,
>  		.dst_fh		= NFS_FH(file_inode(dst)),
>  		.dst_pos	= pos_dst,
>  		.count		= count,
> +		.sync		= false,
>  	};
>  	struct nfs42_copy_res res;
>  	struct nfs4_exception src_exception = {
> diff --git a/fs/nfs/nfs42xdr.c b/fs/nfs/nfs42xdr.c
> index 9e557ad..2c37c66 100644
> --- a/fs/nfs/nfs42xdr.c
> +++ b/fs/nfs/nfs42xdr.c
> @@ -160,7 +160,7 @@ static void encode_copy(struct xdr_stream *xdr,
>  	encode_uint64(xdr, args->count);
>  
>  	encode_uint32(xdr, 1); /* consecutive = true */
> -	encode_uint32(xdr, 1); /* synchronous = true */
> +	encode_uint32(xdr, args->sync);
>  	encode_uint32(xdr, 0); /* src server list */
>  }
>  
> @@ -291,7 +291,8 @@ static void nfs4_xdr_enc_copy(struct rpc_rqst *req,
>  	encode_savefh(xdr, &hdr);
>  	encode_putfh(xdr, args->dst_fh, &hdr);
>  	encode_copy(xdr, args, &hdr);
> -	encode_copy_commit(xdr, args, &hdr);
> +	if (args->sync)
> +		encode_copy_commit(xdr, args, &hdr);
>  	encode_nops(&hdr);
>  }
>  
> @@ -613,7 +614,8 @@ static int nfs4_xdr_dec_copy(struct rpc_rqst *rqstp,
>  	status = decode_copy(xdr, res);
>  	if (status)
>  		goto out;
> -	status = decode_commit(xdr, &res->commit_res);
> +	if (res->commit_res.verf)
> +		status = decode_commit(xdr, &res->commit_res);
>  out:
>  	return status;
>  }
> diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
> index a0282ce..580a8d9 100644
> --- a/include/linux/nfs_fs.h
> +++ b/include/linux/nfs_fs.h
> @@ -183,6 +183,15 @@ struct nfs_inode {
>  	struct inode		vfs_inode;
>  };
>  
> +struct nfs4_copy_state {
> +	struct list_head	copies;
> +	nfs4_stateid		stateid;
> +	struct completion	completion;
> +	uint64_t		count;
> +	struct nfs_writeverf	verf;
> +	int			error;
> +};
> +
>  /*
>   * Cache validity bit flags
>   */
> diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
> index de1eafe..511eefb 100644
> --- a/include/linux/nfs_fs_sb.h
> +++ b/include/linux/nfs_fs_sb.h
> @@ -206,6 +206,7 @@ struct nfs_server {
>  	struct list_head	state_owners_lru;
>  	struct list_head	layouts;
>  	struct list_head	delegations;
> +	struct list_head	ss_copies;
>  
>  	unsigned long		mig_gen;
>  	unsigned long		mig_status;
> diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
> index 784ec8d..020d958 100644
> --- a/include/linux/nfs_xdr.h
> +++ b/include/linux/nfs_xdr.h
> @@ -1384,6 +1384,7 @@ struct nfs42_copy_args {
>  	u64				dst_pos;
>  
>  	u64				count;
> +	bool				sync;
>  };
>  
>  struct nfs42_write_res {
>