Message-ID: <4EC0F7AF.3010904@tonian.com>
Date: Mon, 14 Nov 2011 13:12:47 +0200
From: Benny Halevy <bhalevy@tonian.com>
MIME-Version: 1.0
To: Trond Myklebust <Trond.Myklebust@netapp.com>
CC: linux-nfs@vger.kernel.org
Subject: Re: [PATCH] NFS: Revert pnfs ugliness from the generic NFS read code
 path
References: <1320953896-20898-1-git-send-email-Trond.Myklebust@netapp.com>
In-Reply-To: <1320953896-20898-1-git-send-email-Trond.Myklebust@netapp.com>
Content-Type: text/plain; charset=ISO-8859-1
Sender: linux-nfs-owner@vger.kernel.org

On 2011-11-10 21:38, Trond Myklebust wrote:
> pNFS-specific code belongs in the pnfs layer. It should not be
> hijacking generic NFS read or write code paths.
> 
> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
> ---
>  fs/nfs/internal.h |    2 ++
>  fs/nfs/pnfs.c     |   26 +++++++++++++++++++++-----
>  fs/nfs/read.c     |   14 ++------------
>  3 files changed, 25 insertions(+), 17 deletions(-)
> 
> diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
> index c1a1bd8..3f4d957 100644
> --- a/fs/nfs/internal.h
> +++ b/fs/nfs/internal.h
> @@ -299,6 +299,8 @@ extern void nfs_read_prepare(struct rpc_task *task, void *calldata);
>  extern int nfs_generic_pagein(struct nfs_pageio_descriptor *desc,
>  		struct list_head *head);
>  
> +extern void nfs_pageio_init_read_mds(struct nfs_pageio_descriptor *pgio,
> +		struct inode *inode);
>  extern void nfs_pageio_reset_read_mds(struct nfs_pageio_descriptor *pgio);
>  extern void nfs_readdata_release(struct nfs_read_data *rdata);
>  
> diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
> index baf7353..8e672a2 100644
> --- a/fs/nfs/pnfs.c
> +++ b/fs/nfs/pnfs.c
> @@ -1260,6 +1260,25 @@ pnfs_generic_pg_writepages(struct nfs_pageio_descriptor *desc)
>  }
>  EXPORT_SYMBOL_GPL(pnfs_generic_pg_writepages);
>  
> +static void pnfs_ld_handle_read_error(struct nfs_read_data *data)
> +{
> +	struct nfs_pageio_descriptor pgio;
> +
> +	put_lseg(data->lseg);
> +	data->lseg = NULL;
> +	dprintk("pnfs write error = %d\n", data->pnfs_error);

should be "read error", might as well fix this while you're at it :)

> +
> +	nfs_pageio_init_read_mds(&pgio, data->inode);
> +
> +	while (!list_empty(&data->pages)) {
> +		struct nfs_page *req = nfs_list_entry(data->pages.next);
> +
> +		nfs_list_remove_request(req);
> +		nfs_pageio_add_request(&pgio, req);
> +	}

What about pgio.pg_recoalesce?

Benny

> +	nfs_pageio_complete(&pgio);
> +}
> +
>  /*
>   * Called by non rpc-based layout drivers
>   */
> @@ -1268,11 +1287,8 @@ void pnfs_ld_read_done(struct nfs_read_data *data)
>  	if (likely(!data->pnfs_error)) {
>  		__nfs4_read_done_cb(data);
>  		data->mds_ops->rpc_call_done(&data->task, data);
> -	} else {
> -		put_lseg(data->lseg);
> -		data->lseg = NULL;
> -		dprintk("pnfs write error = %d\n", data->pnfs_error);
> -	}
> +	} else
> +		pnfs_ld_handle_read_error(data);
>  	data->mds_ops->rpc_release(data);
>  }
>  EXPORT_SYMBOL_GPL(pnfs_ld_read_done);
> diff --git a/fs/nfs/read.c b/fs/nfs/read.c
> index 8b48ec6..cfa175c 100644
> --- a/fs/nfs/read.c
> +++ b/fs/nfs/read.c
> @@ -109,7 +109,7 @@ static void nfs_readpage_truncate_uninitialised_page(struct nfs_read_data *data)
>  	}
>  }
>  
> -static void nfs_pageio_init_read_mds(struct nfs_pageio_descriptor *pgio,
> +void nfs_pageio_init_read_mds(struct nfs_pageio_descriptor *pgio,
>  		struct inode *inode)
>  {
>  	nfs_pageio_init(pgio, inode, &nfs_pageio_read_ops,
> @@ -534,23 +534,13 @@ static void nfs_readpage_result_full(struct rpc_task *task, void *calldata)
>  static void nfs_readpage_release_full(void *calldata)
>  {
>  	struct nfs_read_data *data = calldata;
> -	struct nfs_pageio_descriptor pgio;
>  
> -	if (data->pnfs_error) {
> -		nfs_pageio_init_read_mds(&pgio, data->inode);
> -		pgio.pg_recoalesce = 1;
> -	}
>  	while (!list_empty(&data->pages)) {
>  		struct nfs_page *req = nfs_list_entry(data->pages.next);
>  
>  		nfs_list_remove_request(req);
> -		if (!data->pnfs_error)
> -			nfs_readpage_release(req);
> -		else
> -			nfs_pageio_add_request(&pgio, req);
> +		nfs_readpage_release(req);
>  	}
> -	if (data->pnfs_error)
> -		nfs_pageio_complete(&pgio);
>  	nfs_readdata_release(calldata);
>  }
>