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 {