From 7e19d1900fe80a37e2bd5c4138167b5a6fee9d80 Mon Sep 17 00:00:00 2001
From: Trond Myklebust <trond.myklebust@fys.uio.no>
Date: Sat, 10 Apr 2004 21:11:31 -0700
Subject: [PATCH] NFSv2/v3/v4: Add support for asynchronous reads even if
 rsize<PAGE_CACHE_SIZE.

---
 fs/nfs/direct.c         |   1 +
 fs/nfs/nfs3proc.c       |  21 +--
 fs/nfs/nfs4proc.c       |  41 +----
 fs/nfs/nfs4xdr.c        |  22 ++-
 fs/nfs/proc.c           |  21 +--
 fs/nfs/read.c           | 331 ++++++++++++++++++++++++++++++----------
 include/linux/nfs_fs.h  |   1 -
 include/linux/nfs_xdr.h |   6 +-
 8 files changed, 288 insertions(+), 156 deletions(-)

diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 87d17b6e429b..832a38882a61 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -128,6 +128,7 @@ nfs_direct_read_seg(struct inode *inode, struct file *file,
 		.inode		= inode,
 		.args		= {
 			.fh		= NFS_FH(inode),
+			.lockowner	= current->files,
 		},
 		.res		= {
 			.fattr		= &rdata.fattr,
diff --git a/fs/nfs/nfs3proc.c b/fs/nfs/nfs3proc.c
index 5f3443baee69..c75d6373a43c 100644
--- a/fs/nfs/nfs3proc.c
+++ b/fs/nfs/nfs3proc.c
@@ -729,11 +729,10 @@ nfs3_read_done(struct rpc_task *task)
 }
 
 static void
-nfs3_proc_read_setup(struct nfs_read_data *data, unsigned int count)
+nfs3_proc_read_setup(struct nfs_read_data *data)
 {
 	struct rpc_task		*task = &data->task;
 	struct inode		*inode = data->inode;
-	struct nfs_page		*req;
 	int			flags;
 	struct rpc_message	msg = {
 		.rpc_proc	= &nfs3_procedures[NFS3PROC_READ],
@@ -741,27 +740,13 @@ nfs3_proc_read_setup(struct nfs_read_data *data, unsigned int count)
 		.rpc_resp	= &data->res,
 		.rpc_cred	= data->cred,
 	};
-	
-	req = nfs_list_entry(data->pages.next);
-	data->args.fh     = NFS_FH(inode);
-	data->args.offset = req_offset(req);
-	data->args.pgbase = req->wb_pgbase;
-	data->args.pages  = data->pagevec;
-	data->args.count  = count;
-	data->res.fattr   = &data->fattr;
-	data->res.count   = count;
-	data->res.eof     = 0;
-	
+
 	/* N.B. Do we need to test? Never called for swapfile inode */
 	flags = RPC_TASK_ASYNC | (IS_SWAPFILE(inode)? NFS_RPC_SWAPFLAGS : 0);
 
 	/* Finalize the task. */
 	rpc_init_task(task, NFS_CLIENT(inode), nfs3_read_done, flags);
-	task->tk_calldata = data;
-	/* Release requests */
-	task->tk_release = nfs_readdata_release;
-
-	rpc_call_setup(&data->task, &msg, 0);
+	rpc_call_setup(task, &msg, 0);
 }
 
 static void
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 9efe346181bc..689deaa26bb0 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -1096,10 +1096,10 @@ nfs4_proc_read(struct nfs_read_data *rdata, struct file *filp)
 	if (filp) {
 		struct nfs4_state *state;
 		state = (struct nfs4_state *)filp->private_data;
-		nfs4_copy_stateid(&rdata->args.stateid, state, rdata->lockowner);
+		rdata->args.state = state;
 		msg.rpc_cred = state->owner->so_cred;
 	} else {
-		memcpy(&rdata->args.stateid, &zero_stateid, sizeof(rdata->args.stateid));
+		rdata->args.state = NULL;
 		msg.rpc_cred = NFS_I(inode)->mm_cred;
 	}
 
@@ -1509,20 +1509,6 @@ nfs4_proc_pathconf(struct nfs_server *server, struct nfs_fh *fhandle,
 	return nfs4_map_errors(nfs4_call_compound(&compound, NULL, 0));
 }
 
-static void
-nfs4_restart_read(struct rpc_task *task)
-{
-	struct nfs_read_data *data = (struct nfs_read_data *)task->tk_calldata;
-	struct nfs_page *req;
-
-	rpc_restart_call(task);
-	req = nfs_list_entry(data->pages.next);
-	if (req->wb_state)
-		nfs4_copy_stateid(&data->args.stateid, req->wb_state, req->wb_lockowner);
-	else
-		memcpy(&data->args.stateid, &zero_stateid, sizeof(data->args.stateid));
-}
-
 static void
 nfs4_read_done(struct rpc_task *task)
 {
@@ -1530,7 +1516,7 @@ nfs4_read_done(struct rpc_task *task)
 	struct inode *inode = data->inode;
 
 	if (nfs4_async_handle_error(task, NFS_SERVER(inode)) == -EAGAIN) {
-		task->tk_action = nfs4_restart_read;
+		rpc_restart_call(task);
 		return;
 	}
 	if (task->tk_status > 0)
@@ -1540,7 +1526,7 @@ nfs4_read_done(struct rpc_task *task)
 }
 
 static void
-nfs4_proc_read_setup(struct nfs_read_data *data, unsigned int count)
+nfs4_proc_read_setup(struct nfs_read_data *data)
 {
 	struct rpc_task	*task = &data->task;
 	struct rpc_message msg = {
@@ -1550,34 +1536,15 @@ nfs4_proc_read_setup(struct nfs_read_data *data, unsigned int count)
 		.rpc_cred = data->cred,
 	};
 	struct inode *inode = data->inode;
-	struct nfs_page *req = nfs_list_entry(data->pages.next);
 	int flags;
 
-	data->args.fh     = NFS_FH(inode);
-	data->args.offset = req_offset(req);
-	data->args.pgbase = req->wb_pgbase;
-	data->args.pages  = data->pagevec;
-	data->args.count  = count;
-	data->res.fattr   = &data->fattr;
-	data->res.count   = count;
-	data->res.eof     = 0;
 	data->timestamp   = jiffies;
 
-	data->lockowner = req->wb_lockowner;
-	if (req->wb_state)
-		nfs4_copy_stateid(&data->args.stateid, req->wb_state, req->wb_lockowner);
-	else
-		memcpy(&data->args.stateid, &zero_stateid, sizeof(data->args.stateid));
-
 	/* N.B. Do we need to test? Never called for swapfile inode */
 	flags = RPC_TASK_ASYNC | (IS_SWAPFILE(inode)? NFS_RPC_SWAPFLAGS : 0);
 
 	/* Finalize the task. */
 	rpc_init_task(task, NFS_CLIENT(inode), nfs4_read_done, flags);
-	task->tk_calldata = data;
-	/* Release requests */
-	task->tk_release = nfs_readdata_release;
-
 	rpc_call_setup(task, &msg, 0);
 }
 
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 3cf1a83df495..db5be6d7da51 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -868,14 +868,32 @@ encode_putrootfh(struct xdr_stream *xdr)
         return 0;
 }
 
+static void
+encode_stateid(struct xdr_stream *xdr, struct nfs4_state *state, fl_owner_t lockowner)
+{
+	extern nfs4_stateid zero_stateid;
+	nfs4_stateid stateid;
+	uint32_t *p;
+
+	RESERVE_SPACE(16);
+	if (state != NULL) {
+		nfs4_copy_stateid(&stateid, state, lockowner);
+		WRITEMEM(stateid.data, sizeof(stateid.data));
+	} else
+		WRITEMEM(zero_stateid.data, sizeof(zero_stateid.data));
+}
+
 static int
 encode_read(struct xdr_stream *xdr, struct nfs_readargs *args)
 {
 	uint32_t *p;
 
-	RESERVE_SPACE(32);
+	RESERVE_SPACE(4);
 	WRITE32(OP_READ);
-	WRITEMEM(args->stateid.data, sizeof(args->stateid.data));
+
+	encode_stateid(xdr, args->state, args->lockowner);
+
+	RESERVE_SPACE(12);
 	WRITE64(args->offset);
 	WRITE32(args->count);
 
diff --git a/fs/nfs/proc.c b/fs/nfs/proc.c
index ca4eccd03adf..6756717a7e76 100644
--- a/fs/nfs/proc.c
+++ b/fs/nfs/proc.c
@@ -559,11 +559,10 @@ nfs_read_done(struct rpc_task *task)
 }
 
 static void
-nfs_proc_read_setup(struct nfs_read_data *data, unsigned int count)
+nfs_proc_read_setup(struct nfs_read_data *data)
 {
 	struct rpc_task		*task = &data->task;
 	struct inode		*inode = data->inode;
-	struct nfs_page		*req;
 	int			flags;
 	struct rpc_message	msg = {
 		.rpc_proc	= &nfs_procedures[NFSPROC_READ],
@@ -571,27 +570,13 @@ nfs_proc_read_setup(struct nfs_read_data *data, unsigned int count)
 		.rpc_resp	= &data->res,
 		.rpc_cred	= data->cred,
 	};
-	
-	req = nfs_list_entry(data->pages.next);
-	data->args.fh     = NFS_FH(inode);
-	data->args.offset = req_offset(req);
-	data->args.pgbase = req->wb_pgbase;
-	data->args.pages  = data->pagevec;
-	data->args.count  = count;
-	data->res.fattr   = &data->fattr;
-	data->res.count   = count;
-	data->res.eof     = 0;
-	
+
 	/* N.B. Do we need to test? Never called for swapfile inode */
 	flags = RPC_TASK_ASYNC | (IS_SWAPFILE(inode)? NFS_RPC_SWAPFLAGS : 0);
 
 	/* Finalize the task. */
 	rpc_init_task(task, NFS_CLIENT(inode), nfs_read_done, flags);
-	task->tk_calldata = data;
-	/* Release requests */
-	task->tk_release = nfs_readdata_release;
-
-	rpc_call_setup(&data->task, &msg, 0);
+	rpc_call_setup(task, &msg, 0);
 }
 
 static void
diff --git a/fs/nfs/read.c b/fs/nfs/read.c
index 4b929887c5a4..c7b8ae327ad7 100644
--- a/fs/nfs/read.c
+++ b/fs/nfs/read.c
@@ -35,6 +35,8 @@
 #define NFSDBG_FACILITY		NFSDBG_PAGECACHE
 
 static int nfs_pagein_one(struct list_head *, struct inode *);
+static void nfs_readpage_result_partial(struct nfs_read_data *, int);
+static void nfs_readpage_result_full(struct nfs_read_data *, int);
 
 static kmem_cache_t *nfs_rdata_cachep;
 static mempool_t *nfs_rdata_mempool;
@@ -57,12 +59,37 @@ static __inline__ void nfs_readdata_free(struct nfs_read_data *p)
 	mempool_free(p, nfs_rdata_mempool);
 }
 
-void nfs_readdata_release(struct rpc_task *task)
+static void nfs_readdata_release(struct rpc_task *task)
 {
         struct nfs_read_data   *data = (struct nfs_read_data *)task->tk_calldata;
         nfs_readdata_free(data);
 }
 
+static
+unsigned int nfs_page_length(struct inode *inode, struct page *page)
+{
+	loff_t i_size = i_size_read(inode);
+	unsigned long idx;
+
+	if (i_size <= 0)
+		return 0;
+	idx = (i_size - 1) >> PAGE_CACHE_SHIFT;
+	if (page->index > idx)
+		return 0;
+	if (page->index != idx)
+		return PAGE_CACHE_SIZE;
+	return 1 + ((i_size - 1) & (PAGE_CACHE_SIZE - 1));
+}
+
+static
+int nfs_return_empty_page(struct page *page)
+{
+	memclear_highpage_flush(page, 0, PAGE_CACHE_SIZE);
+	SetPageUptodate(page);
+	unlock_page(page);
+	return 0;
+}
+
 /*
  * Read a page synchronously.
  */
@@ -78,6 +105,7 @@ nfs_readpage_sync(struct file *file, struct inode *inode, struct page *page)
 		.inode		= inode,
 		.args		= {
 			.fh		= NFS_FH(inode),
+			.lockowner	= current->files,
 			.pages		= &page,
 			.pgbase		= 0UL,
 			.count		= rsize,
@@ -146,89 +174,208 @@ nfs_readpage_async(struct file *file, struct inode *inode, struct page *page)
 {
 	LIST_HEAD(one_request);
 	struct nfs_page	*new;
+	unsigned int len;
 
-	new = nfs_create_request(file, inode, page, 0, PAGE_CACHE_SIZE);
+	len = nfs_page_length(inode, page);
+	if (len == 0)
+		return nfs_return_empty_page(page);
+	new = nfs_create_request(file, inode, page, 0, len);
 	if (IS_ERR(new)) {
 		unlock_page(page);
 		return PTR_ERR(new);
 	}
+	if (len < PAGE_CACHE_SIZE)
+		memclear_highpage_flush(page, len, PAGE_CACHE_SIZE - len);
+
 	nfs_lock_request(new);
 	nfs_list_add_request(new, &one_request);
 	nfs_pagein_one(&one_request, inode);
 	return 0;
 }
 
+static void nfs_readpage_release(struct nfs_page *req)
+{
+	unlock_page(req->wb_page);
+
+	nfs_clear_request(req);
+	nfs_release_request(req);
+	nfs_unlock_request(req);
+
+	dprintk("NFS: read done (%s/%Ld %d@%Ld)\n",
+			req->wb_inode->i_sb->s_id,
+			(long long)NFS_FILEID(req->wb_inode),
+			req->wb_bytes,
+			(long long)req_offset(req));
+}
+
 /*
  * Set up the NFS read request struct
  */
-static void
-nfs_read_rpcsetup(struct list_head *head, struct nfs_read_data *data)
+static void nfs_read_rpcsetup(struct nfs_page *req, struct nfs_read_data *data,
+		unsigned int count, unsigned int offset)
 {
 	struct inode		*inode;
-	struct nfs_page		*req;
-	struct page		**pages;
-	unsigned int		count;
 
-	pages = data->pagevec;
-	count = 0;
-	while (!list_empty(head)) {
-		req = nfs_list_entry(head->next);
-		nfs_list_remove_request(req);
-		nfs_list_add_request(req, &data->pages);
-		*pages++ = req->wb_page;
-		count += req->wb_bytes;
-	}
-	req = nfs_list_entry(data->pages.next);
+	data->req	  = req;
 	data->inode	  = inode = req->wb_inode;
 	data->cred	  = req->wb_cred;
 
-	NFS_PROTO(inode)->read_setup(data, count);
+	data->args.fh     = NFS_FH(inode);
+	data->args.offset = req_offset(req) + offset;
+	data->args.pgbase = req->wb_pgbase + offset;
+	data->args.pages  = data->pagevec;
+	data->args.count  = count;
+	data->args.lockowner = req->wb_lockowner;
+	data->args.state  = req->wb_state;
+
+	data->res.fattr   = &data->fattr;
+	data->res.count   = count;
+	data->res.eof     = 0;
+
+	NFS_PROTO(inode)->read_setup(data);
 
-	dprintk("NFS: %4d initiated read call (req %s/%Ld, %u bytes @ offset %Lu.\n",
+	data->task.tk_calldata = data;
+	/* Release requests */
+	data->task.tk_release = nfs_readdata_release;
+
+	dprintk("NFS: %4d initiated read call (req %s/%Ld, %u bytes @ offset %Lu)\n",
 			data->task.tk_pid,
 			inode->i_sb->s_id,
 			(long long)NFS_FILEID(inode),
 			count,
-			(unsigned long long)req_offset(req));
+			(unsigned long long)data->args.offset);
 }
 
 static void
 nfs_async_read_error(struct list_head *head)
 {
 	struct nfs_page	*req;
-	struct page	*page;
 
 	while (!list_empty(head)) {
 		req = nfs_list_entry(head->next);
-		page = req->wb_page;
 		nfs_list_remove_request(req);
-		SetPageError(page);
-		unlock_page(page);
-		nfs_clear_request(req);
-		nfs_release_request(req);
-		nfs_unlock_request(req);
+		SetPageError(req->wb_page);
+		nfs_readpage_release(req);
 	}
 }
 
-static int
-nfs_pagein_one(struct list_head *head, struct inode *inode)
+/*
+ * Start an async read operation
+ */
+static void nfs_execute_read(struct nfs_read_data *data)
+{
+	struct rpc_clnt *clnt = NFS_CLIENT(data->inode);
+	sigset_t oldset;
+
+	rpc_clnt_sigmask(clnt, &oldset);
+	lock_kernel();
+	rpc_execute(&data->task);
+	unlock_kernel();
+	rpc_clnt_sigunmask(clnt, &oldset);
+}
+
+/*
+ * Generate multiple requests to fill a single page.
+ *
+ * We optimize to reduce the number of read operations on the wire.  If we
+ * detect that we're reading a page, or an area of a page, that is past the
+ * end of file, we do not generate NFS read operations but just clear the
+ * parts of the page that would have come back zero from the server anyway.
+ *
+ * We rely on the cached value of i_size to make this determination; another
+ * client can fill pages on the server past our cached end-of-file, but we
+ * won't see the new data until our attribute cache is updated.  This is more
+ * or less conventional NFS client behavior.
+ */
+static int nfs_pagein_multi(struct list_head *head, struct inode *inode)
 {
-	struct rpc_clnt		*clnt = NFS_CLIENT(inode);
+	struct nfs_page *req = nfs_list_entry(head->next);
+	struct page *page = req->wb_page;
+	struct nfs_read_data *data;
+	unsigned int rsize = NFS_SERVER(inode)->rsize;
+	unsigned int nbytes, offset;
+	int requests = 0;
+	LIST_HEAD(list);
+
+	nfs_list_remove_request(req);
+
+	nbytes = req->wb_bytes;
+	for(;;) {
+		data = nfs_readdata_alloc();
+		if (!data)
+			goto out_bad;
+		list_add(&data->pages, &list);
+		requests++;
+		if (nbytes <= rsize)
+			break;
+		nbytes -= rsize;
+	}
+	atomic_set(&req->wb_complete, requests);
+
+	ClearPageError(page);
+	offset = 0;
+	nbytes = req->wb_bytes;
+	do {
+		data = list_entry(list.next, struct nfs_read_data, pages);
+		list_del_init(&data->pages);
+
+		data->pagevec[0] = page;
+		data->complete = nfs_readpage_result_partial;
+
+		if (nbytes > rsize) {
+			nfs_read_rpcsetup(req, data, rsize, offset);
+			offset += rsize;
+			nbytes -= rsize;
+		} else {
+			nfs_read_rpcsetup(req, data, nbytes, offset);
+			nbytes = 0;
+		}
+		nfs_execute_read(data);
+	} while (nbytes != 0);
+
+	return 0;
+
+out_bad:
+	while (!list_empty(&list)) {
+		data = list_entry(list.next, struct nfs_read_data, pages);
+		list_del(&data->pages);
+		nfs_readdata_free(data);
+	}
+	SetPageError(page);
+	nfs_readpage_release(req);
+	return -ENOMEM;
+}
+
+static int nfs_pagein_one(struct list_head *head, struct inode *inode)
+{
+	struct nfs_page		*req;
+	struct page		**pages;
 	struct nfs_read_data	*data;
-	sigset_t		oldset;
+	unsigned int		count;
+
+	if (NFS_SERVER(inode)->rsize < PAGE_CACHE_SIZE)
+		return nfs_pagein_multi(head, inode);
 
 	data = nfs_readdata_alloc();
 	if (!data)
 		goto out_bad;
 
-	nfs_read_rpcsetup(head, data);
+	pages = data->pagevec;
+	count = 0;
+	while (!list_empty(head)) {
+		req = nfs_list_entry(head->next);
+		nfs_list_remove_request(req);
+		nfs_list_add_request(req, &data->pages);
+		ClearPageError(req->wb_page);
+		*pages++ = req->wb_page;
+		count += req->wb_bytes;
+	}
+	req = nfs_list_entry(data->pages.next);
+
+	data->complete = nfs_readpage_result_full;
+	nfs_read_rpcsetup(req, data, count, 0);
 
-	/* Start the async call */
-	rpc_clnt_sigmask(clnt, &oldset);
-	lock_kernel();
-	rpc_execute(&data->task);
-	unlock_kernel();
-	rpc_clnt_sigunmask(clnt, &oldset);
+	nfs_execute_read(data);
 	return 0;
 out_bad:
 	nfs_async_read_error(head);
@@ -257,56 +404,85 @@ nfs_pagein_list(struct list_head *head, int rpages)
 	return error;
 }
 
+/*
+ * Handle a read reply that fills part of a page.
+ */
+static void nfs_readpage_result_partial(struct nfs_read_data *data, int status)
+{
+	struct nfs_page *req = data->req;
+	struct page *page = req->wb_page;
+ 
+	if (status >= 0) {
+		unsigned int request = data->args.count;
+		unsigned int result = data->res.count;
+
+		if (result < request) {
+			memclear_highpage_flush(page,
+						data->args.pgbase + result,
+						request - result);
+			if (!data->res.eof)
+				SetPageError(page);
+		}
+	} else
+		SetPageError(page);
+
+	if (atomic_dec_and_test(&req->wb_complete)) {
+		if (!PageError(page))
+			SetPageUptodate(page);
+		nfs_readpage_release(req);
+	}
+}
+
 /*
  * This is the callback from RPC telling us whether a reply was
  * received or some error occurred (timeout or socket shutdown).
  */
-void
-nfs_readpage_result(struct rpc_task *task)
+static void nfs_readpage_result_full(struct nfs_read_data *data, int status)
 {
-	struct nfs_read_data *data = (struct nfs_read_data *)task->tk_calldata;
 	unsigned int count = data->res.count;
 
-	dprintk("NFS: %4d nfs_readpage_result, (status %d)\n",
-		task->tk_pid, task->tk_status);
-
-	NFS_FLAGS(data->inode) |= NFS_INO_INVALID_ATIME;
 	while (!list_empty(&data->pages)) {
 		struct nfs_page *req = nfs_list_entry(data->pages.next);
 		struct page *page = req->wb_page;
 		nfs_list_remove_request(req);
 
-		if (task->tk_status >= 0) {
+		if (status >= 0) {
 			if (count < PAGE_CACHE_SIZE) {
-				memclear_highpage_flush(page,
+				if (count < req->wb_bytes)
+					memclear_highpage_flush(page,
 							req->wb_pgbase + count,
 							req->wb_bytes - count);
-
+				if (!data->res.eof)
+					SetPageError(page);
 				count = 0;
 			} else
 				count -= PAGE_CACHE_SIZE;
 			SetPageUptodate(page);
 		} else
 			SetPageError(page);
-		unlock_page(page);
-
-		dprintk("NFS: read (%s/%Ld %d@%Ld)\n",
-                        req->wb_inode->i_sb->s_id,
-                        (long long)NFS_FILEID(req->wb_inode),
-                        req->wb_bytes,
-                        (long long)req_offset(req));
-		nfs_clear_request(req);
-		nfs_release_request(req);
-		nfs_unlock_request(req);
+		nfs_readpage_release(req);
 	}
 }
 
+/*
+ * This is the callback from RPC telling us whether a reply was
+ * received or some error occurred (timeout or socket shutdown).
+ */
+void nfs_readpage_result(struct rpc_task *task)
+{
+	struct nfs_read_data *data = (struct nfs_read_data *)task->tk_calldata;
+	int status = task->tk_status;
+
+	dprintk("NFS: %4d nfs_readpage_result, (status %d)\n",
+		task->tk_pid, status);
+
+	NFS_FLAGS(data->inode) |= NFS_INO_INVALID_ATIME;
+	data->complete(data, status);
+}
+
 /*
  * Read a page over NFS.
- * We read the page synchronously in the following cases:
- *  -	The NFS rsize is smaller than PAGE_CACHE_SIZE. We could kludge our way
- *	around this by creating several consecutive read requests, but
- *	that's hardly worth it.
+ * We read the page synchronously in the following case:
  *  -	The error flag is set for this page. This happens only when a
  *	previous async read operation failed.
  */
@@ -329,7 +505,7 @@ nfs_readpage(struct file *file, struct page *page)
 	if (error)
 		goto out_error;
 
-	if (!PageError(page) && NFS_SERVER(inode)->rsize >= PAGE_CACHE_SIZE) {
+	if (!IS_SYNC(inode)) {
 		error = nfs_readpage_async(file, inode, page);
 		goto out;
 	}
@@ -350,27 +526,26 @@ struct nfs_readdesc {
 	struct file *filp;
 };
 
-static int
-readpage_sync_filler(void *data, struct page *page)
-{
-	struct nfs_readdesc *desc = (struct nfs_readdesc *)data;
-	return nfs_readpage_sync(desc->filp, page->mapping->host, page);
-}
-
 static int
 readpage_async_filler(void *data, struct page *page)
 {
 	struct nfs_readdesc *desc = (struct nfs_readdesc *)data;
 	struct inode *inode = page->mapping->host;
 	struct nfs_page *new;
+	unsigned int len;
 
 	nfs_wb_page(inode, page);
-	new = nfs_create_request(desc->filp, inode, page, 0, PAGE_CACHE_SIZE);
+	len = nfs_page_length(inode, page);
+	if (len == 0)
+		return nfs_return_empty_page(page);
+	new = nfs_create_request(desc->filp, inode, page, 0, len);
 	if (IS_ERR(new)) {
 			SetPageError(page);
 			unlock_page(page);
 			return PTR_ERR(new);
 	}
+	if (len < PAGE_CACHE_SIZE)
+		memclear_highpage_flush(page, len, PAGE_CACHE_SIZE - len);
 	nfs_lock_request(new);
 	nfs_list_add_request(new, desc->head);
 	return 0;
@@ -385,14 +560,16 @@ nfs_readpages(struct file *filp, struct address_space *mapping,
 		.filp		= filp,
 		.head		= &head,
 	};
-	struct nfs_server *server = NFS_SERVER(mapping->host);
-	int is_sync = server->rsize < PAGE_CACHE_SIZE;
+	struct inode *inode = mapping->host;
+	struct nfs_server *server = NFS_SERVER(inode);
 	int ret;
 
-	ret = read_cache_pages(mapping, pages,
-			       is_sync ? readpage_sync_filler :
-					 readpage_async_filler,
-			       &desc);
+	dprintk("NFS: nfs_readpages (%s/%Ld %d)\n",
+			inode->i_sb->s_id,
+			(long long)NFS_FILEID(inode),
+			nr_pages);
+
+	ret = read_cache_pages(mapping, pages, readpage_async_filler, &desc);
 	if (!list_empty(&head)) {
 		int err = nfs_pagein_list(&head, server->rpages);
 		if (!ret)
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index 47123702fbd5..92ed40acf4ae 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -397,7 +397,6 @@ extern int  nfs_readpages(struct file *, struct address_space *,
 		struct list_head *, unsigned);
 extern int  nfs_pagein_list(struct list_head *, int);
 extern void nfs_readpage_result(struct rpc_task *);
-extern void nfs_readdata_release(struct rpc_task *);
 
 /*
  * linux/fs/mount_clnt.c
diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
index f93789122786..ba9051dfddfe 100644
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@@ -229,7 +229,8 @@ struct nfs_lockres {
 
 struct nfs_readargs {
 	struct nfs_fh *		fh;
-	nfs4_stateid		stateid;
+	fl_owner_t		lockowner;
+	struct nfs4_state *	state;
 	__u64			offset;
 	__u32			count;
 	unsigned int		pgbase;
@@ -663,7 +664,6 @@ struct nfs_read_data {
 	struct rpc_task		task;
 	struct inode		*inode;
 	struct rpc_cred		*cred;
-	fl_owner_t		lockowner;
 	struct nfs_fattr	fattr;	/* fattr storage */
 	struct list_head	pages;	/* Coalesced read requests */
 	struct nfs_page		*req;	/* multi ops per nfs_page */
@@ -741,7 +741,7 @@ struct nfs_rpc_ops {
 	int	(*pathconf) (struct nfs_server *, struct nfs_fh *,
 			     struct nfs_pathconf *);
 	u32 *	(*decode_dirent)(u32 *, struct nfs_entry *, int plus);
-	void	(*read_setup)   (struct nfs_read_data *, unsigned int count);
+	void	(*read_setup)   (struct nfs_read_data *);
 	void	(*write_setup)  (struct nfs_write_data *, unsigned int count, int how);
 	void	(*commit_setup) (struct nfs_write_data *, u64 start, u32 len, int how);
 	int	(*file_open)   (struct inode *, struct file *);
-- 
2.30.9