Re: [PATCH 1/2] nfs: remove ->write_pageio_init from rpc ops

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

On 04/16/2014 09:07 AM, Christoph Hellwig wrote:
> The write_pageio_init method is just a very convoluted way to grab the
> right nfs_pageio_ops vector.  The vector to chose is not a choice of
> protocol version, but just a pNFS vs MDS I/O choice that can simply be
> done inside nfs_pageio_init_write based on the presence of a layout
> driver, and a new force_mds flag to the special case of falling back
> to MDS I/O on a pNFS-capable volume.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

> ---
>  fs/nfs/direct.c         |    4 ++--
>  fs/nfs/internal.h       |    2 +-
>  fs/nfs/nfs3proc.c       |    1 -
>  fs/nfs/nfs4proc.c       |    1 -
>  fs/nfs/pnfs.c           |   16 +---------------
>  fs/nfs/pnfs.h           |    8 --------
>  fs/nfs/proc.c           |    1 -
>  fs/nfs/write.c          |   21 +++++++++++++--------
>  include/linux/nfs_xdr.h |    2 --
>  9 files changed, 17 insertions(+), 39 deletions(-)
>
> diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
> index b8797ae..6a31102 100644
> --- a/fs/nfs/direct.c
> +++ b/fs/nfs/direct.c
> @@ -564,7 +564,7 @@ static void nfs_direct_write_reschedule(struct nfs_direct_req *dreq)
>  	dreq->count = 0;
>  	get_dreq(dreq);
>  
> -	NFS_PROTO(dreq->inode)->write_pageio_init(&desc, dreq->inode, FLUSH_STABLE,
> +	nfs_pageio_init_write(&desc, dreq->inode, FLUSH_STABLE, false,
>  			      &nfs_direct_write_completion_ops);
>  	desc.pg_dreq = dreq;
>  
> @@ -874,7 +874,7 @@ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq,
>  	size_t requested_bytes = 0;
>  	unsigned long seg;
>  
> -	NFS_PROTO(inode)->write_pageio_init(&desc, inode, FLUSH_COND_STABLE,
> +	nfs_pageio_init_write(&desc, inode, FLUSH_COND_STABLE, false,
>  			      &nfs_direct_write_completion_ops);
>  	desc.pg_dreq = dreq;
>  	get_dreq(dreq);
> diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
> index dd8bfc2..8431083 100644
> --- a/fs/nfs/internal.h
> +++ b/fs/nfs/internal.h
> @@ -422,7 +422,7 @@ int nfs_remount(struct super_block *sb, int *flags, char *raw_data);
>  
>  /* write.c */
>  extern void nfs_pageio_init_write(struct nfs_pageio_descriptor *pgio,
> -			struct inode *inode, int ioflags,
> +			struct inode *inode, int ioflags, bool force_mds,
>  			const struct nfs_pgio_completion_ops *compl_ops);
>  extern struct nfs_write_header *nfs_writehdr_alloc(void);
>  extern void nfs_writehdr_free(struct nfs_pgio_header *hdr);
> diff --git a/fs/nfs/nfs3proc.c b/fs/nfs/nfs3proc.c
> index db60149..e984880 100644
> --- a/fs/nfs/nfs3proc.c
> +++ b/fs/nfs/nfs3proc.c
> @@ -951,7 +951,6 @@ const struct nfs_rpc_ops nfs_v3_clientops = {
>  	.read_rpc_prepare = nfs3_proc_read_rpc_prepare,
>  	.read_done	= nfs3_read_done,
>  	.write_setup	= nfs3_proc_write_setup,
> -	.write_pageio_init = nfs_pageio_init_write,
>  	.write_rpc_prepare = nfs3_proc_write_rpc_prepare,
>  	.write_done	= nfs3_write_done,
>  	.commit_setup	= nfs3_proc_commit_setup,
> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
> index 397be39..8da0c62 100644
> --- a/fs/nfs/nfs4proc.c
> +++ b/fs/nfs/nfs4proc.c
> @@ -8437,7 +8437,6 @@ const struct nfs_rpc_ops nfs_v4_clientops = {
>  	.read_rpc_prepare = nfs4_proc_read_rpc_prepare,
>  	.read_done	= nfs4_read_done,
>  	.write_setup	= nfs4_proc_write_setup,
> -	.write_pageio_init = pnfs_pageio_init_write,
>  	.write_rpc_prepare = nfs4_proc_write_rpc_prepare,
>  	.write_done	= nfs4_write_done,
>  	.commit_setup	= nfs4_proc_commit_setup,
> diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
> index cb53d45..9edac9f 100644
> --- a/fs/nfs/pnfs.c
> +++ b/fs/nfs/pnfs.c
> @@ -1447,20 +1447,6 @@ pnfs_pageio_init_read(struct nfs_pageio_descriptor *pgio, struct inode *inode,
>  		nfs_pageio_init(pgio, inode, ld->pg_read_ops, compl_ops, server->rsize, 0);
>  }
>  
> -void
> -pnfs_pageio_init_write(struct nfs_pageio_descriptor *pgio, struct inode *inode,
> -		       int ioflags,
> -		       const struct nfs_pgio_completion_ops *compl_ops)
> -{
> -	struct nfs_server *server = NFS_SERVER(inode);
> -	struct pnfs_layoutdriver_type *ld = server->pnfs_curr_ld;
> -
> -	if (ld == NULL)
> -		nfs_pageio_init_write(pgio, inode, ioflags, compl_ops);
> -	else
> -		nfs_pageio_init(pgio, inode, ld->pg_write_ops, compl_ops, server->wsize, ioflags);
> -}
> -
>  bool
>  pnfs_generic_pg_test(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev,
>  		     struct nfs_page *req)
> @@ -1496,7 +1482,7 @@ int pnfs_write_done_resend_to_mds(struct inode *inode,
>  	LIST_HEAD(failed);
>  
>  	/* Resend all requests through the MDS */
> -	nfs_pageio_init_write(&pgio, inode, FLUSH_STABLE, compl_ops);
> +	nfs_pageio_init_write(&pgio, inode, FLUSH_STABLE, true, compl_ops);
>  	pgio.pg_dreq = dreq;
>  	while (!list_empty(head)) {
>  		struct nfs_page *req = nfs_list_entry(head->next);
> diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
> index 0237939..e9ac8fb 100644
> --- a/fs/nfs/pnfs.h
> +++ b/fs/nfs/pnfs.h
> @@ -182,8 +182,6 @@ void pnfs_put_lseg(struct pnfs_layout_segment *lseg);
>  
>  void pnfs_pageio_init_read(struct nfs_pageio_descriptor *, struct inode *,
>  			   const struct nfs_pgio_completion_ops *);
> -void pnfs_pageio_init_write(struct nfs_pageio_descriptor *, struct inode *,
> -			    int, const struct nfs_pgio_completion_ops *);
>  
>  void set_pnfs_layoutdriver(struct nfs_server *, const struct nfs_fh *, u32);
>  void unset_pnfs_layoutdriver(struct nfs_server *);
> @@ -467,12 +465,6 @@ static inline void pnfs_pageio_init_read(struct nfs_pageio_descriptor *pgio, str
>  	nfs_pageio_init_read(pgio, inode, compl_ops);
>  }
>  
> -static inline void pnfs_pageio_init_write(struct nfs_pageio_descriptor *pgio, struct inode *inode, int ioflags,
> -					  const struct nfs_pgio_completion_ops *compl_ops)
> -{
> -	nfs_pageio_init_write(pgio, inode, ioflags, compl_ops);
> -}
> -
>  static inline int
>  pnfs_commit_list(struct inode *inode, struct list_head *mds_pages, int how,
>  		 struct nfs_commit_info *cinfo)
> diff --git a/fs/nfs/proc.c b/fs/nfs/proc.c
> index e55ce9e..f9cc295 100644
> --- a/fs/nfs/proc.c
> +++ b/fs/nfs/proc.c
> @@ -739,7 +739,6 @@ const struct nfs_rpc_ops nfs_v2_clientops = {
>  	.read_rpc_prepare = nfs_proc_read_rpc_prepare,
>  	.read_done	= nfs_read_done,
>  	.write_setup	= nfs_proc_write_setup,
> -	.write_pageio_init = nfs_pageio_init_write,
>  	.write_rpc_prepare = nfs_proc_write_rpc_prepare,
>  	.write_done	= nfs_write_done,
>  	.commit_setup	= nfs_proc_commit_setup,
> diff --git a/fs/nfs/write.c b/fs/nfs/write.c
> index 9a3b6a4..0bd1724 100644
> --- a/fs/nfs/write.c
> +++ b/fs/nfs/write.c
> @@ -354,10 +354,8 @@ static int nfs_writepage_locked(struct page *page, struct writeback_control *wbc
>  	struct nfs_pageio_descriptor pgio;
>  	int err;
>  
> -	NFS_PROTO(page_file_mapping(page)->host)->write_pageio_init(&pgio,
> -							  page->mapping->host,
> -							  wb_priority(wbc),
> -							  &nfs_async_write_completion_ops);
> +	nfs_pageio_init_write(&pgio, page->mapping->host, wb_priority(wbc),
> +				false, &nfs_async_write_completion_ops);
>  	err = nfs_do_writepage(page, wbc, &pgio);
>  	nfs_pageio_complete(&pgio);
>  	if (err < 0)
> @@ -400,7 +398,8 @@ int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
>  
>  	nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGES);
>  
> -	NFS_PROTO(inode)->write_pageio_init(&pgio, inode, wb_priority(wbc), &nfs_async_write_completion_ops);
> +	nfs_pageio_init_write(&pgio, inode, wb_priority(wbc), false,
> +				&nfs_async_write_completion_ops);
>  	err = write_cache_pages(mapping, wbc, nfs_writepages_callback, &pgio);
>  	nfs_pageio_complete(&pgio);
>  
> @@ -1282,11 +1281,17 @@ static const struct nfs_pageio_ops nfs_pageio_write_ops = {
>  };
>  
>  void nfs_pageio_init_write(struct nfs_pageio_descriptor *pgio,
> -			       struct inode *inode, int ioflags,
> +			       struct inode *inode, int ioflags, bool force_mds,
>  			       const struct nfs_pgio_completion_ops *compl_ops)
>  {
> -	nfs_pageio_init(pgio, inode, &nfs_pageio_write_ops, compl_ops,
> -				NFS_SERVER(inode)->wsize, ioflags);
> +	struct nfs_server *server = NFS_SERVER(inode);
> +	const struct nfs_pageio_ops *pg_ops = &nfs_pageio_write_ops;
> +
> +#ifdef CONFIG_NFS_V4_1
> +	if (server->pnfs_curr_ld && !force_mds)
> +		pg_ops = server->pnfs_curr_ld->pg_write_ops;
> +#endif
> +	nfs_pageio_init(pgio, inode, pg_ops, compl_ops, server->wsize, ioflags);
>  }
>  EXPORT_SYMBOL_GPL(nfs_pageio_init_write);
>  
> diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
> index 6fb5b23..78216f8 100644
> --- a/include/linux/nfs_xdr.h
> +++ b/include/linux/nfs_xdr.h
> @@ -1471,8 +1471,6 @@ struct nfs_rpc_ops {
>  	int	(*read_rpc_prepare)(struct rpc_task *, struct nfs_read_data *);
>  	int	(*read_done)  (struct rpc_task *, struct nfs_read_data *);
>  	void	(*write_setup)  (struct nfs_write_data *, struct rpc_message *);
> -	void	(*write_pageio_init)(struct nfs_pageio_descriptor *, struct inode *, int,
> -				     const struct nfs_pgio_completion_ops *);
>  	int	(*write_rpc_prepare)(struct rpc_task *, struct nfs_write_data *);
>  	int	(*write_done)  (struct rpc_task *, struct nfs_write_data *);
>  	void	(*commit_setup) (struct nfs_commit_data *, struct rpc_message *);