--- zzzz-none-000/linux-3.10.107/include/linux/nfs_page.h	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/include/linux/nfs_page.h	2021-02-04 17:41:59.000000000 +0000
@@ -22,12 +22,17 @@
  * Valid flags for a dirty buffer
  */
 enum {
-	PG_BUSY = 0,
-	PG_MAPPED,
-	PG_CLEAN,
-	PG_NEED_COMMIT,
-	PG_NEED_RESCHED,
-	PG_COMMIT_TO_DS,
+	PG_BUSY = 0,		/* nfs_{un}lock_request */
+	PG_MAPPED,		/* page private set for buffered io */
+	PG_CLEAN,		/* write succeeded */
+	PG_COMMIT_TO_DS,	/* used by pnfs layouts */
+	PG_INODE_REF,		/* extra ref held by inode when in writeback */
+	PG_HEADLOCK,		/* page group lock of wb_head */
+	PG_TEARDOWN,		/* page group sync for destroy */
+	PG_UNLOCKPAGE,		/* page group sync bit in read path */
+	PG_UPTODATE,		/* page group sync bit in read path */
+	PG_WB_END,		/* page group sync bit in write path */
+	PG_REMOVE,		/* page group sync bit in write path */
 };
 
 struct nfs_inode;
@@ -43,26 +48,47 @@
 	struct kref		wb_kref;	/* reference count */
 	unsigned long		wb_flags;
 	struct nfs_write_verifier	wb_verf;	/* Commit cookie */
+	struct nfs_page		*wb_this_page;  /* list of reqs for this page */
+	struct nfs_page		*wb_head;       /* head pointer for req list */
 };
 
 struct nfs_pageio_descriptor;
 struct nfs_pageio_ops {
 	void	(*pg_init)(struct nfs_pageio_descriptor *, struct nfs_page *);
-	bool	(*pg_test)(struct nfs_pageio_descriptor *, struct nfs_page *, struct nfs_page *);
+	size_t	(*pg_test)(struct nfs_pageio_descriptor *, struct nfs_page *,
+			   struct nfs_page *);
 	int	(*pg_doio)(struct nfs_pageio_descriptor *);
+	unsigned int	(*pg_get_mirror_count)(struct nfs_pageio_descriptor *,
+				       struct nfs_page *);
+	void	(*pg_cleanup)(struct nfs_pageio_descriptor *);
 };
 
-struct nfs_pageio_descriptor {
+struct nfs_rw_ops {
+	const fmode_t rw_mode;
+	struct nfs_pgio_header *(*rw_alloc_header)(void);
+	void (*rw_free_header)(struct nfs_pgio_header *);
+	int  (*rw_done)(struct rpc_task *, struct nfs_pgio_header *,
+			struct inode *);
+	void (*rw_result)(struct rpc_task *, struct nfs_pgio_header *);
+	void (*rw_initiate)(struct nfs_pgio_header *, struct rpc_message *,
+			    const struct nfs_rpc_ops *,
+			    struct rpc_task_setup *, int);
+};
+
+struct nfs_pgio_mirror {
 	struct list_head	pg_list;
 	unsigned long		pg_bytes_written;
 	size_t			pg_count;
 	size_t			pg_bsize;
 	unsigned int		pg_base;
-	unsigned char		pg_moreio : 1,
-				pg_recoalesce : 1;
+	unsigned char		pg_recoalesce : 1;
+};
 
+struct nfs_pageio_descriptor {
+	unsigned char		pg_moreio : 1;
 	struct inode		*pg_inode;
 	const struct nfs_pageio_ops *pg_ops;
+	const struct nfs_rw_ops *pg_rw_ops;
 	int 			pg_ioflags;
 	int			pg_error;
 	const struct rpc_call_ops *pg_rpc_callops;
@@ -70,34 +96,51 @@
 	struct pnfs_layout_segment *pg_lseg;
 	struct nfs_direct_req	*pg_dreq;
 	void			*pg_layout_private;
+	unsigned int		pg_bsize;	/* default bsize for mirrors */
+
+	u32			pg_mirror_count;
+	struct nfs_pgio_mirror	*pg_mirrors;
+	struct nfs_pgio_mirror	pg_mirrors_static[1];
+	struct nfs_pgio_mirror	*pg_mirrors_dynamic;
+	u32			pg_mirror_idx;	/* current mirror */
 };
 
+/* arbitrarily selected limit to number of mirrors */
+#define NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX 16
+
 #define NFS_WBACK_BUSY(req)	(test_bit(PG_BUSY,&(req)->wb_flags))
 
 extern	struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
-					    struct inode *inode,
 					    struct page *page,
+					    struct nfs_page *last,
 					    unsigned int offset,
 					    unsigned int count);
-extern	void nfs_release_request(struct nfs_page *req);
+extern	void nfs_release_request(struct nfs_page *);
 
 
 extern	void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
 			     struct inode *inode,
 			     const struct nfs_pageio_ops *pg_ops,
 			     const struct nfs_pgio_completion_ops *compl_ops,
+			     const struct nfs_rw_ops *rw_ops,
 			     size_t bsize,
 			     int how);
 extern	int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
 				   struct nfs_page *);
+extern  int nfs_pageio_resend(struct nfs_pageio_descriptor *,
+			      struct nfs_pgio_header *);
 extern	void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
 extern	void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
-extern bool nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
+extern size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
 				struct nfs_page *prev,
 				struct nfs_page *req);
 extern  int nfs_wait_on_request(struct nfs_page *);
 extern	void nfs_unlock_request(struct nfs_page *req);
-extern	void nfs_unlock_and_release_request(struct nfs_page *req);
+extern	void nfs_unlock_and_release_request(struct nfs_page *);
+extern int nfs_page_group_lock(struct nfs_page *, bool);
+extern void nfs_page_group_lock_wait(struct nfs_page *);
+extern void nfs_page_group_unlock(struct nfs_page *);
+extern bool nfs_page_group_sync_on_bit(struct nfs_page *, unsigned int);
 
 /*
  * Lock the page of an asynchronous request