NFS: merge _full and _partial read rpc_ops

Decouple nfs_pgio_header and nfs_read_data, and have (possibly
multiple) nfs_read_datas each take a refcount on nfs_pgio_header.

For the moment keeps nfs_read_header as a way to preallocate a single
nfs_read_data with the nfs_pgio_header.  The code doesn't need this,
and would be prettier without, but given the amount of churn I am
already introducing I didn't want to play with tuning new mempools.

This also fixes bug in pnfs_ld_handle_read_error.  In the case of
desc->pg_bsize < PAGE_CACHE_SIZE, the pages list was empty, causing
replay attempt to do nothing.

Signed-off-by: Fred Isaman <iisaman@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
index e34beaf86e9c..164862148ba0 100644
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@@ -1187,14 +1187,30 @@ struct nfs_read_data {
 	struct nfs_client	*ds_clp;	/* pNFS data server */
 };
 
+/* used as flag bits in nfs_pgio_header */
+enum {
+	NFS_IOHDR_ERROR = 0,
+	NFS_IOHDR_EOF,
+	NFS_IOHDR_REDO,
+};
+
 struct nfs_pgio_header {
 	struct inode		*inode;
 	struct rpc_cred		*cred;
 	struct list_head	pages;
+	struct list_head	rpc_list;
+	atomic_t		refcnt;
 	struct nfs_page		*req;
 	struct pnfs_layout_segment *lseg;
+	loff_t			io_start;
 	const struct rpc_call_ops *mds_ops;
+	void (*release) (struct nfs_pgio_header *hdr);
+	spinlock_t		lock;
+	/* fields protected by lock */
 	int			pnfs_error;
+	int			error;		/* merge with pnfs_error */
+	unsigned long		good_bytes;	/* boundary of good data */
+	unsigned long		flags;
 };
 
 struct nfs_read_header {