[pnfs] [PATCH 06/11] pnfs: pnfs_modify_new_request

[Benny Halevy]

On Apr. 10, 2008, 17:05 +0300, Fred Isaman <iisaman at citi.umich.edu> wrote:
> Add hook into nfs_page initialization to allow for setting of
> PG_USE_PNFS.
> 
> Signed-off-by: Fred Isaman <iisaman at citi.umich.edu>
> Signed-off-by: Benny Halevy <bhalevy at panasas.com>
> ---
>  fs/nfs/pagelist.c         |    1 +
>  fs/nfs/pnfs.c             |   19 +++++++++++++++++++
>  fs/nfs/pnfs.h             |   18 ++++++++++++++++++
>  include/linux/nfs4_pnfs.h |    3 +++
>  4 files changed, 41 insertions(+), 0 deletions(-)
> 
> diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
> index 43634d3..1bd1c13 100644
> --- a/fs/nfs/pagelist.c
> +++ b/fs/nfs/pagelist.c
> @@ -87,6 +87,7 @@ nfs_create_request(struct nfs_open_context *ctx, struct inode *inode,
>  	req->wb_bytes   = count;
>  	req->wb_context = get_nfs_open_context(ctx);
>  	kref_init(&req->wb_kref);
> +	pnfs_modify_new_request(inode, req, fsdata);
>  	return req;
>  }
>  
> diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
> index 7be8bbe..2666100 100644
> --- a/fs/nfs/pnfs.c
> +++ b/fs/nfs/pnfs.c
> @@ -1922,6 +1922,25 @@ out_unlock:
>  	goto out;
>  }
>  
> +/* Note that fsdata != NULL */
> +void _pnfs_modify_new_write_request(struct nfs_server *nfss,

Passing nfss can be easily avoided as it can be derived from inode.

> +				    struct inode *inode, struct nfs_page *req,

inode can be derived from req as well.

> +				    struct pnfs_fsdata *fsdata)
> +{
> +	struct pnfs_layout_segment *lseg = NULL;
> +	loff_t pos;
> +	unsigned count;
> +
> +	pos = ((loff_t)req->wb_index << PAGE_CACHE_SHIFT) + req->wb_offset;
> +	count = req->wb_bytes;
> +	lseg = pnfs_find_get_lseg(inode, pos, count, IOMODE_RW);
> +	if (lseg) {
> +		if (fsdata->ok_to_use_pnfs)
> +			set_bit(PG_USE_PNFS, &req->wb_flags);
> +		put_lseg(lseg);
> +	}
> +}
> +
>  void pnfs_free_request_data(struct nfs_page *req)
>  {
>  	struct layoutdriver_io_operations *lo;
> diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
> index 0c63fea..e8361cd 100644
> --- a/fs/nfs/pnfs.h
> +++ b/fs/nfs/pnfs.h
> @@ -65,6 +65,9 @@ int _pnfs_write_begin(struct inode *inode, struct nfs_server *nfss,
>  		      unsigned flags, struct pnfs_fsdata **fsdata);
>  int _pnfs_do_flush(struct inode *inode, struct nfs_server *nfss,
>  		   struct nfs_page *req, struct pnfs_fsdata *fsdata);
> +void _pnfs_modify_new_write_request(struct nfs_server *nfss,
> +				    struct inode *inode, struct nfs_page *req,
> +				    struct pnfs_fsdata *fsdata);
>  
>  #define PNFS_EXISTS_LDIO_OP(srv, opname) ((srv)->pnfs_curr_ld &&	\
>  				     (srv)->pnfs_curr_ld->ld_io_ops &&	\
> @@ -146,6 +149,15 @@ static inline void pnfs_write_end_cleanup(void *fsdata)
>  	pnfs_free_fsdata((struct pnfs_fsdata *) fsdata);
>  }
>  
> +static inline void pnfs_modify_new_request(struct inode *inode,
> +					   struct nfs_page *req,
> +					   void *fsdata)
> +{
> +	struct nfs_server *nfss = NFS_SERVER(inode);
> +	if (fsdata)


Are you assuming the if fsdata != NULL new_request must be defined?
If so, this better be documented.

> +		_pnfs_modify_new_write_request(nfss, inode, req, fsdata);

else?
Who sets PG_USE_PNFS?

> +}
> +
>  #else  /* CONFIG_PNFS */
>  
>  static inline int pnfs_try_to_read_data(struct nfs_read_data *data,
> @@ -182,6 +194,12 @@ static inline void pnfs_write_end_cleanup(void *fsdata)
>  {
>  }
>  
> +static inline void pnfs_modify_new_request(struct inode *inode,
> +					   struct nfs_page *req,
> +					   void *fsdata)
> +{
> +}
> +
>  #endif /* CONFIG_PNFS */
>  
>  #endif /* FS_NFS_PNFS_H */
> diff --git a/include/linux/nfs4_pnfs.h b/include/linux/nfs4_pnfs.h
> index 9ed6819..8881739 100644
> --- a/include/linux/nfs4_pnfs.h
> +++ b/include/linux/nfs4_pnfs.h
> @@ -141,6 +141,9 @@ struct layoutdriver_io_operations {
>  	int (*write_begin) (struct pnfs_layout_segment *lseg, struct page *page,
>  			    loff_t pos, unsigned count,
>  			    struct pnfs_fsdata *fsdata);
> +	void (*new_request)(struct pnfs_layout_segment *lseg,
> +			    struct nfs_page *req, loff_t pos, unsigned count,
> +			    struct pnfs_fsdata *fsdata);
>  	void (*free_request_data) (struct nfs_page *);
>  	void (*free_fsdata) (struct pnfs_fsdata *data);
>