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

[Fredric Isaman]

On Sun, 13 Apr 2008, Benny Halevy wrote:

> 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.
>

OK


>> +				    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.
>

As per Dean's suggestion, there is no LD new_request function.

>> +		_pnfs_modify_new_write_request(nfss, inode, req, fsdata);
>
> else?
> Who sets PG_USE_PNFS?
>

I don't know.  Right now, it works for block, and should not alter the 
behavior of the other drivers, since all the checks for it are in the LD 
code. It would work for me if, in the NULL case, PG_USE_PNFS were always 
set.

 	Fred


>> +}
>> +
>>  #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);
>>
>
>