[pnfs] [PATCH 07/11] pnfs: pnfs_write_end

[Benny Halevy]

On Apr. 10, 2008, 17:05 +0300, Fred Isaman <iisaman at citi.umich.edu> wrote:
> Add hooks in the nfs_write_end path, giving a driver the potential for
> post-copy manipulation of the page.
> 
> Signed-off-by: Fred Isaman <iisaman at citi.umich.edu>
> Signed-off-by: Benny Halevy <bhalevy at panasas.com>
> ---
>  fs/nfs/file.c             |    4 ++++
>  fs/nfs/pnfs.c             |   16 ++++++++++++++++
>  fs/nfs/pnfs.h             |   24 ++++++++++++++++++++++++
>  fs/nfs/write.c            |    2 +-
>  include/linux/nfs4_pnfs.h |    3 +++
>  5 files changed, 48 insertions(+), 1 deletions(-)
> 
> diff --git a/fs/nfs/file.c b/fs/nfs/file.c
> index aa0f37d..0ac2406 100644
> --- a/fs/nfs/file.c
> +++ b/fs/nfs/file.c
> @@ -371,10 +371,14 @@ static int nfs_write_end(struct file *file, struct address_space *mapping,
>  	unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
>  	int status;
>  
> +	status = pnfs_write_end(file, page, pos, len, copied, fsdata);
> +	if (status)
> +		goto out;
>  	lock_kernel();
>  	status = nfs_updatepage(file, page, offset, copied, fsdata);
>  	unlock_kernel();
>  
> + out:
>  	unlock_page(page);
>  	page_cache_release(page);
>  	pnfs_write_end_cleanup(fsdata);
> diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
> index 2666100..a0b80c2 100644
> --- a/fs/nfs/pnfs.c
> +++ b/fs/nfs/pnfs.c
> @@ -1594,6 +1594,22 @@ int _pnfs_write_begin(struct inode *inode, struct nfs_server *nfss,
>  	return status;
>  }
>  
> +/* Return 0 on succes, negative on failure */
> +/* CAREFUL - what happens if copied < len??? */
> +int _pnfs_write_end(struct inode *inode, struct nfs_server *nfss,

ditto nfss.

> +		    struct page *page, loff_t pos, unsigned len,
> +		    unsigned copied, struct pnfs_fsdata *fsdata)
> +{
> +	struct pnfs_layout_segment *lseg;
> +	int status;
> +
> +	lseg = pnfs_find_get_lseg(inode, pos, len, IOMODE_RW);
> +	status = nfss->pnfs_curr_ld->ld_io_ops->write_end(inode, page,
> +						pos, len, copied, fsdata);
> +	put_lseg(lseg);
> +	return status;
> +}
> +
>  /* Given an nfs request, determine if it should be flushed before proceeding.
>   * It should default to returning False, returning True only if there is a
>   * specific reason to flush.
> diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
> index e8361cd..10a921f 100644
> --- a/fs/nfs/pnfs.h
> +++ b/fs/nfs/pnfs.h
> @@ -63,6 +63,9 @@ void pnfs_layout_release(struct pnfs_layout_type *);
>  int _pnfs_write_begin(struct inode *inode, struct nfs_server *nfss,
>  		      struct page *page, loff_t pos, unsigned len,
>  		      unsigned flags, struct pnfs_fsdata **fsdata);
> +int _pnfs_write_end(struct inode *inode, struct nfs_server *nfss,
> +		    struct page *page, loff_t pos, unsigned len,
> +		    unsigned copied, 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,
> @@ -144,6 +147,20 @@ static inline int pnfs_do_flush(struct nfs_page *req, void *fsdata)
>  		return 0;
>  }
>  
> +static inline int pnfs_write_end(struct file *filp, struct page *page,
> +				 loff_t pos, unsigned len, unsigned copied,
> +				 void *fsdata)
> +{
> +	struct inode *inode = filp->f_dentry->d_inode;
> +	struct nfs_server *nfss = NFS_SERVER(inode);
> +
> +	if (PNFS_EXISTS_LDIO_OP(nfss, write_end))
> +		return _pnfs_write_end(inode, nfss, page, pos, len, copied,
> +				       fsdata);
> +	else
> +		return 0;
> +}
> +
>  static inline void pnfs_write_end_cleanup(void *fsdata)
>  {
>  	pnfs_free_fsdata((struct pnfs_fsdata *) fsdata);
> @@ -190,6 +207,13 @@ static inline int pnfs_write_begin(struct file *filp, struct page *page,
>  	return 0;
>  }
>  
> +static inline int pnfs_write_end(struct file *filp, struct page *page,
> +				 loff_t pos, unsigned len, unsigned copied,
> +				 void *fsdata)
> +{
> +	return 0;
> +}
> +
>  static inline void pnfs_write_end_cleanup(void *fsdata)
>  {
>  }
> diff --git a/fs/nfs/write.c b/fs/nfs/write.c
> index 5cdd1ee..05d16a9 100644
> --- a/fs/nfs/write.c
> +++ b/fs/nfs/write.c
> @@ -657,7 +657,7 @@ static struct nfs_page * nfs_update_request(struct nfs_open_context* ctx,
>  	rqend = req->wb_offset + req->wb_bytes;
>  	if (req->wb_context != ctx
>  	    || req->wb_page != page
> -	    || !nfs_dirty_request(req)
> +	    || !nfs_dirty_request(req) || pnfs_do_flush(req, fsdata)

Does this really belong in this patch or in patch 3, pnfs_write_begin.
Even better, looks like pnfs_do_flush can be coded in a patch of its own, no?

>  	    || offset > rqend || end < req->wb_offset) {
>  		nfs_clear_page_tag_locked(req);
>  		return ERR_PTR(-EBUSY);
> diff --git a/include/linux/nfs4_pnfs.h b/include/linux/nfs4_pnfs.h
> index 8881739..d9a231f 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);
> +	int (*write_end)(struct inode *inode, struct page *page, loff_t pos,
> +			 unsigned count, unsigned copied,
> +			 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);