pageio_init simplifications, V2

pageio_init simplifications, V2

[Christoph Hellwig]

Changes since last version:

 - add the missing exports as pointed out by Anna
 - handle the pnfs fallback to MDS case correctly

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

[Christoph Hellwig]

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>
---
 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 *);
-- 
1.7.10.4

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

[Anna Schumaker]

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 *);

[PATCH 2/2] nfs: remove ->read_pageio_init from rpc ops

[Christoph Hellwig]

The read_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>
---
 fs/nfs/direct.c         |    2 +-
 fs/nfs/internal.h       |    2 +-
 fs/nfs/nfs3proc.c       |    1 -
 fs/nfs/nfs4proc.c       |    1 -
 fs/nfs/pnfs.c           |   15 +--------------
 fs/nfs/pnfs.h           |    9 ---------
 fs/nfs/proc.c           |    1 -
 fs/nfs/read.c           |   19 ++++++++++++++-----
 include/linux/nfs_xdr.h |    2 --
 9 files changed, 17 insertions(+), 35 deletions(-)

diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 6a31102..bbe688e 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -424,7 +424,7 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
 	size_t requested_bytes = 0;
 	unsigned long seg;
 
-	NFS_PROTO(dreq->inode)->read_pageio_init(&desc, dreq->inode,
+	nfs_pageio_init_read(&desc, dreq->inode, false,
 			     &nfs_direct_read_completion_ops);
 	get_dreq(dreq);
 	desc.pg_dreq = dreq;
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 8431083..98fe618 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -398,7 +398,7 @@ struct nfs_pgio_completion_ops;
 extern struct nfs_read_header *nfs_readhdr_alloc(void);
 extern void nfs_readhdr_free(struct nfs_pgio_header *hdr);
 extern void nfs_pageio_init_read(struct nfs_pageio_descriptor *pgio,
-			struct inode *inode,
+			struct inode *inode, bool force_mds,
 			const struct nfs_pgio_completion_ops *compl_ops);
 extern int nfs_initiate_read(struct rpc_clnt *clnt,
 			     struct nfs_read_data *data,
diff --git a/fs/nfs/nfs3proc.c b/fs/nfs/nfs3proc.c
index e984880..d873241 100644
--- a/fs/nfs/nfs3proc.c
+++ b/fs/nfs/nfs3proc.c
@@ -947,7 +947,6 @@ const struct nfs_rpc_ops nfs_v3_clientops = {
 	.pathconf	= nfs3_proc_pathconf,
 	.decode_dirent	= nfs3_decode_dirent,
 	.read_setup	= nfs3_proc_read_setup,
-	.read_pageio_init = nfs_pageio_init_read,
 	.read_rpc_prepare = nfs3_proc_read_rpc_prepare,
 	.read_done	= nfs3_read_done,
 	.write_setup	= nfs3_proc_write_setup,
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 8da0c62..21cd1f2 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -8433,7 +8433,6 @@ const struct nfs_rpc_ops nfs_v4_clientops = {
 	.set_capabilities = nfs4_server_capabilities,
 	.decode_dirent	= nfs4_decode_dirent,
 	.read_setup	= nfs4_proc_read_setup,
-	.read_pageio_init = pnfs_pageio_init_read,
 	.read_rpc_prepare = nfs4_proc_read_rpc_prepare,
 	.read_done	= nfs4_read_done,
 	.write_setup	= nfs4_proc_write_setup,
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 9edac9f..3d5bc2b 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -1434,19 +1434,6 @@ pnfs_generic_pg_init_write(struct nfs_pageio_descriptor *pgio,
 }
 EXPORT_SYMBOL_GPL(pnfs_generic_pg_init_write);
 
-void
-pnfs_pageio_init_read(struct nfs_pageio_descriptor *pgio, struct inode *inode,
-		      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_read(pgio, inode, compl_ops);
-	else
-		nfs_pageio_init(pgio, inode, ld->pg_read_ops, compl_ops, server->rsize, 0);
-}
-
 bool
 pnfs_generic_pg_test(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev,
 		     struct nfs_page *req)
@@ -1641,7 +1628,7 @@ int pnfs_read_done_resend_to_mds(struct inode *inode,
 	LIST_HEAD(failed);
 
 	/* Resend all requests through the MDS */
-	nfs_pageio_init_read(&pgio, inode, compl_ops);
+	nfs_pageio_init_read(&pgio, inode, 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 e9ac8fb..94a9a18 100644
--- a/fs/nfs/pnfs.h
+++ b/fs/nfs/pnfs.h
@@ -180,9 +180,6 @@ extern int nfs4_proc_layoutreturn(struct nfs4_layoutreturn *lrp);
 void pnfs_get_layout_hdr(struct pnfs_layout_hdr *lo);
 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 set_pnfs_layoutdriver(struct nfs_server *, const struct nfs_fh *, u32);
 void unset_pnfs_layoutdriver(struct nfs_server *);
 void pnfs_generic_pg_init_read(struct nfs_pageio_descriptor *, struct nfs_page *);
@@ -459,12 +456,6 @@ static inline void unset_pnfs_layoutdriver(struct nfs_server *s)
 {
 }
 
-static inline void pnfs_pageio_init_read(struct nfs_pageio_descriptor *pgio, struct inode *inode,
-					 const struct nfs_pgio_completion_ops *compl_ops)
-{
-	nfs_pageio_init_read(pgio, inode, 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 f9cc295..8cc227f 100644
--- a/fs/nfs/proc.c
+++ b/fs/nfs/proc.c
@@ -735,7 +735,6 @@ const struct nfs_rpc_ops nfs_v2_clientops = {
 	.pathconf	= nfs_proc_pathconf,
 	.decode_dirent	= nfs2_decode_dirent,
 	.read_setup	= nfs_proc_read_setup,
-	.read_pageio_init = nfs_pageio_init_read,
 	.read_rpc_prepare = nfs_proc_read_rpc_prepare,
 	.read_done	= nfs_read_done,
 	.write_setup	= nfs_proc_write_setup,
diff --git a/fs/nfs/read.c b/fs/nfs/read.c
index 411aedd..7f87461 100644
--- a/fs/nfs/read.c
+++ b/fs/nfs/read.c
@@ -24,6 +24,7 @@
 #include "internal.h"
 #include "iostat.h"
 #include "fscache.h"
+#include "pnfs.h"
 
 #define NFSDBG_FACILITY		NFSDBG_PAGECACHE
 
@@ -114,11 +115,17 @@ int nfs_return_empty_page(struct page *page)
 }
 
 void nfs_pageio_init_read(struct nfs_pageio_descriptor *pgio,
-			      struct inode *inode,
+			      struct inode *inode, bool force_mds,
 			      const struct nfs_pgio_completion_ops *compl_ops)
 {
-	nfs_pageio_init(pgio, inode, &nfs_pageio_read_ops, compl_ops,
-			NFS_SERVER(inode)->rsize, 0);
+	struct nfs_server *server = NFS_SERVER(inode);
+	const struct nfs_pageio_ops *pg_ops = &nfs_pageio_read_ops;
+
+#ifdef CONFIG_NFS_V4_1
+	if (server->pnfs_curr_ld && !force_mds)
+		pg_ops = server->pnfs_curr_ld->pg_read_ops;
+#endif
+	nfs_pageio_init(pgio, inode, pg_ops, compl_ops, server->rsize, 0);
 }
 EXPORT_SYMBOL_GPL(nfs_pageio_init_read);
 
@@ -147,7 +154,8 @@ int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode,
 	if (len < PAGE_CACHE_SIZE)
 		zero_user_segment(page, len, PAGE_CACHE_SIZE);
 
-	NFS_PROTO(inode)->read_pageio_init(&pgio, inode, &nfs_async_read_completion_ops);
+	nfs_pageio_init_read(&pgio, inode, false,
+			     &nfs_async_read_completion_ops);
 	nfs_pageio_add_request(&pgio, new);
 	nfs_pageio_complete(&pgio);
 	NFS_I(inode)->read_io += pgio.pg_bytes_written;
@@ -654,7 +662,8 @@ int nfs_readpages(struct file *filp, struct address_space *mapping,
 	if (ret == 0)
 		goto read_complete; /* all pages were read */
 
-	NFS_PROTO(inode)->read_pageio_init(&pgio, inode, &nfs_async_read_completion_ops);
+	nfs_pageio_init_read(&pgio, inode, false,
+			     &nfs_async_read_completion_ops);
 
 	ret = read_cache_pages(mapping, pages, readpage_async_filler, &desc);
 
diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
index 78216f8..3e8fc1f 100644
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@@ -1466,8 +1466,6 @@ struct nfs_rpc_ops {
 	int	(*set_capabilities)(struct nfs_server *, struct nfs_fh *);
 	int	(*decode_dirent)(struct xdr_stream *, struct nfs_entry *, int);
 	void	(*read_setup)   (struct nfs_read_data *, struct rpc_message *);
-	void	(*read_pageio_init)(struct nfs_pageio_descriptor *, struct inode *,
-				    const struct nfs_pgio_completion_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 *);
-- 
1.7.10.4

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

[Anna Schumaker]

On 04/16/2014 09:07 AM, Christoph Hellwig wrote:
> The read_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>
The commit message for this patch needs to change "nfs_pageio_init_write" into "nfs_pageio_init_read".  I haven't had any problems with the code!

Tested-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

> ---
>  fs/nfs/direct.c         |    2 +-
>  fs/nfs/internal.h       |    2 +-
>  fs/nfs/nfs3proc.c       |    1 -
>  fs/nfs/nfs4proc.c       |    1 -
>  fs/nfs/pnfs.c           |   15 +--------------
>  fs/nfs/pnfs.h           |    9 ---------
>  fs/nfs/proc.c           |    1 -
>  fs/nfs/read.c           |   19 ++++++++++++++-----
>  include/linux/nfs_xdr.h |    2 --
>  9 files changed, 17 insertions(+), 35 deletions(-)
>
> diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
> index 6a31102..bbe688e 100644
> --- a/fs/nfs/direct.c
> +++ b/fs/nfs/direct.c
> @@ -424,7 +424,7 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
>  	size_t requested_bytes = 0;
>  	unsigned long seg;
>  
> -	NFS_PROTO(dreq->inode)->read_pageio_init(&desc, dreq->inode,
> +	nfs_pageio_init_read(&desc, dreq->inode, false,
>  			     &nfs_direct_read_completion_ops);
>  	get_dreq(dreq);
>  	desc.pg_dreq = dreq;
> diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
> index 8431083..98fe618 100644
> --- a/fs/nfs/internal.h
> +++ b/fs/nfs/internal.h
> @@ -398,7 +398,7 @@ struct nfs_pgio_completion_ops;
>  extern struct nfs_read_header *nfs_readhdr_alloc(void);
>  extern void nfs_readhdr_free(struct nfs_pgio_header *hdr);
>  extern void nfs_pageio_init_read(struct nfs_pageio_descriptor *pgio,
> -			struct inode *inode,
> +			struct inode *inode, bool force_mds,
>  			const struct nfs_pgio_completion_ops *compl_ops);
>  extern int nfs_initiate_read(struct rpc_clnt *clnt,
>  			     struct nfs_read_data *data,
> diff --git a/fs/nfs/nfs3proc.c b/fs/nfs/nfs3proc.c
> index e984880..d873241 100644
> --- a/fs/nfs/nfs3proc.c
> +++ b/fs/nfs/nfs3proc.c
> @@ -947,7 +947,6 @@ const struct nfs_rpc_ops nfs_v3_clientops = {
>  	.pathconf	= nfs3_proc_pathconf,
>  	.decode_dirent	= nfs3_decode_dirent,
>  	.read_setup	= nfs3_proc_read_setup,
> -	.read_pageio_init = nfs_pageio_init_read,
>  	.read_rpc_prepare = nfs3_proc_read_rpc_prepare,
>  	.read_done	= nfs3_read_done,
>  	.write_setup	= nfs3_proc_write_setup,
> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
> index 8da0c62..21cd1f2 100644
> --- a/fs/nfs/nfs4proc.c
> +++ b/fs/nfs/nfs4proc.c
> @@ -8433,7 +8433,6 @@ const struct nfs_rpc_ops nfs_v4_clientops = {
>  	.set_capabilities = nfs4_server_capabilities,
>  	.decode_dirent	= nfs4_decode_dirent,
>  	.read_setup	= nfs4_proc_read_setup,
> -	.read_pageio_init = pnfs_pageio_init_read,
>  	.read_rpc_prepare = nfs4_proc_read_rpc_prepare,
>  	.read_done	= nfs4_read_done,
>  	.write_setup	= nfs4_proc_write_setup,
> diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
> index 9edac9f..3d5bc2b 100644
> --- a/fs/nfs/pnfs.c
> +++ b/fs/nfs/pnfs.c
> @@ -1434,19 +1434,6 @@ pnfs_generic_pg_init_write(struct nfs_pageio_descriptor *pgio,
>  }
>  EXPORT_SYMBOL_GPL(pnfs_generic_pg_init_write);
>  
> -void
> -pnfs_pageio_init_read(struct nfs_pageio_descriptor *pgio, struct inode *inode,
> -		      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_read(pgio, inode, compl_ops);
> -	else
> -		nfs_pageio_init(pgio, inode, ld->pg_read_ops, compl_ops, server->rsize, 0);
> -}
> -
>  bool
>  pnfs_generic_pg_test(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev,
>  		     struct nfs_page *req)
> @@ -1641,7 +1628,7 @@ int pnfs_read_done_resend_to_mds(struct inode *inode,
>  	LIST_HEAD(failed);
>  
>  	/* Resend all requests through the MDS */
> -	nfs_pageio_init_read(&pgio, inode, compl_ops);
> +	nfs_pageio_init_read(&pgio, inode, 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 e9ac8fb..94a9a18 100644
> --- a/fs/nfs/pnfs.h
> +++ b/fs/nfs/pnfs.h
> @@ -180,9 +180,6 @@ extern int nfs4_proc_layoutreturn(struct nfs4_layoutreturn *lrp);
>  void pnfs_get_layout_hdr(struct pnfs_layout_hdr *lo);
>  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 set_pnfs_layoutdriver(struct nfs_server *, const struct nfs_fh *, u32);
>  void unset_pnfs_layoutdriver(struct nfs_server *);
>  void pnfs_generic_pg_init_read(struct nfs_pageio_descriptor *, struct nfs_page *);
> @@ -459,12 +456,6 @@ static inline void unset_pnfs_layoutdriver(struct nfs_server *s)
>  {
>  }
>  
> -static inline void pnfs_pageio_init_read(struct nfs_pageio_descriptor *pgio, struct inode *inode,
> -					 const struct nfs_pgio_completion_ops *compl_ops)
> -{
> -	nfs_pageio_init_read(pgio, inode, 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 f9cc295..8cc227f 100644
> --- a/fs/nfs/proc.c
> +++ b/fs/nfs/proc.c
> @@ -735,7 +735,6 @@ const struct nfs_rpc_ops nfs_v2_clientops = {
>  	.pathconf	= nfs_proc_pathconf,
>  	.decode_dirent	= nfs2_decode_dirent,
>  	.read_setup	= nfs_proc_read_setup,
> -	.read_pageio_init = nfs_pageio_init_read,
>  	.read_rpc_prepare = nfs_proc_read_rpc_prepare,
>  	.read_done	= nfs_read_done,
>  	.write_setup	= nfs_proc_write_setup,
> diff --git a/fs/nfs/read.c b/fs/nfs/read.c
> index 411aedd..7f87461 100644
> --- a/fs/nfs/read.c
> +++ b/fs/nfs/read.c
> @@ -24,6 +24,7 @@
>  #include "internal.h"
>  #include "iostat.h"
>  #include "fscache.h"
> +#include "pnfs.h"
>  
>  #define NFSDBG_FACILITY		NFSDBG_PAGECACHE
>  
> @@ -114,11 +115,17 @@ int nfs_return_empty_page(struct page *page)
>  }
>  
>  void nfs_pageio_init_read(struct nfs_pageio_descriptor *pgio,
> -			      struct inode *inode,
> +			      struct inode *inode, bool force_mds,
>  			      const struct nfs_pgio_completion_ops *compl_ops)
>  {
> -	nfs_pageio_init(pgio, inode, &nfs_pageio_read_ops, compl_ops,
> -			NFS_SERVER(inode)->rsize, 0);
> +	struct nfs_server *server = NFS_SERVER(inode);
> +	const struct nfs_pageio_ops *pg_ops = &nfs_pageio_read_ops;
> +
> +#ifdef CONFIG_NFS_V4_1
> +	if (server->pnfs_curr_ld && !force_mds)
> +		pg_ops = server->pnfs_curr_ld->pg_read_ops;
> +#endif
> +	nfs_pageio_init(pgio, inode, pg_ops, compl_ops, server->rsize, 0);
>  }
>  EXPORT_SYMBOL_GPL(nfs_pageio_init_read);
>  
> @@ -147,7 +154,8 @@ int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode,
>  	if (len < PAGE_CACHE_SIZE)
>  		zero_user_segment(page, len, PAGE_CACHE_SIZE);
>  
> -	NFS_PROTO(inode)->read_pageio_init(&pgio, inode, &nfs_async_read_completion_ops);
> +	nfs_pageio_init_read(&pgio, inode, false,
> +			     &nfs_async_read_completion_ops);
>  	nfs_pageio_add_request(&pgio, new);
>  	nfs_pageio_complete(&pgio);
>  	NFS_I(inode)->read_io += pgio.pg_bytes_written;
> @@ -654,7 +662,8 @@ int nfs_readpages(struct file *filp, struct address_space *mapping,
>  	if (ret == 0)
>  		goto read_complete; /* all pages were read */
>  
> -	NFS_PROTO(inode)->read_pageio_init(&pgio, inode, &nfs_async_read_completion_ops);
> +	nfs_pageio_init_read(&pgio, inode, false,
> +			     &nfs_async_read_completion_ops);
>  
>  	ret = read_cache_pages(mapping, pages, readpage_async_filler, &desc);
>  
> diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
> index 78216f8..3e8fc1f 100644
> --- a/include/linux/nfs_xdr.h
> +++ b/include/linux/nfs_xdr.h
> @@ -1466,8 +1466,6 @@ struct nfs_rpc_ops {
>  	int	(*set_capabilities)(struct nfs_server *, struct nfs_fh *);
>  	int	(*decode_dirent)(struct xdr_stream *, struct nfs_entry *, int);
>  	void	(*read_setup)   (struct nfs_read_data *, struct rpc_message *);
> -	void	(*read_pageio_init)(struct nfs_pageio_descriptor *, struct inode *,
> -				    const struct nfs_pgio_completion_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 *);

Re: pageio_init simplifications, V2

[Trond Myklebust]

On Wed, Apr 16, 2014 at 9:07 AM, Christoph Hellwig <hch@lst.de> wrote:
> Changes since last version:
>
>  - add the missing exports as pointed out by Anna
>  - handle the pnfs fallback to MDS case correctly
>

Thanks! Applied...


-- 
Trond Myklebust

Linux NFS client maintainer, PrimaryData

trond.myklebust@primarydata.com