1 files changed, 280 insertions, 489 deletions

diff --git a/fs/nfs/read.c b/fs/nfs/read.c
index 70a26c651f09..3c1fa320b3f1 100644
--- a/fs/nfs/read.c
+++ b/fs/nfs/read.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * linux/fs/nfs/read.c
  *
@@ -14,6 +15,7 @@
 #include <linux/stat.h>
 #include <linux/mm.h>
 #include <linux/slab.h>
+#include <linux/task_io_accounting_ops.h>
 #include <linux/pagemap.h>
 #include <linux/sunrpc/clnt.h>
 #include <linux/nfs_fs.h>
@@ -24,653 +26,434 @@
 #include "internal.h"
 #include "iostat.h"
 #include "fscache.h"
+#include "pnfs.h"
+#include "nfstrace.h"
+#include "delegation.h"
 
 #define NFSDBG_FACILITY		NFSDBG_PAGECACHE
 
-static const struct nfs_pageio_ops nfs_pageio_read_ops;
-static const struct rpc_call_ops nfs_read_common_ops;
-static const struct nfs_pgio_completion_ops nfs_async_read_completion_ops;
+const struct nfs_pgio_completion_ops nfs_async_read_completion_ops;
+static const struct nfs_rw_ops nfs_rw_read_ops;
 
 static struct kmem_cache *nfs_rdata_cachep;
 
-struct nfs_read_header *nfs_readhdr_alloc(void)
+static struct nfs_pgio_header *nfs_readhdr_alloc(void)
 {
-	struct nfs_read_header *rhdr;
+	struct nfs_pgio_header *p = kmem_cache_zalloc(nfs_rdata_cachep, GFP_KERNEL);
 
-	rhdr = kmem_cache_zalloc(nfs_rdata_cachep, GFP_KERNEL);
-	if (rhdr) {
-		struct nfs_pgio_header *hdr = &rhdr->header;
-
-		INIT_LIST_HEAD(&hdr->pages);
-		INIT_LIST_HEAD(&hdr->rpc_list);
-		spin_lock_init(&hdr->lock);
-		atomic_set(&hdr->refcnt, 0);
-	}
-	return rhdr;
-}
-EXPORT_SYMBOL_GPL(nfs_readhdr_alloc);
-
-static struct nfs_read_data *nfs_readdata_alloc(struct nfs_pgio_header *hdr,
-						unsigned int pagecount)
-{
-	struct nfs_read_data *data, *prealloc;
-
-	prealloc = &container_of(hdr, struct nfs_read_header, header)->rpc_data;
-	if (prealloc->header == NULL)
-		data = prealloc;
-	else
-		data = kzalloc(sizeof(*data), GFP_KERNEL);
-	if (!data)
-		goto out;
-
-	if (nfs_pgarray_set(&data->pages, pagecount)) {
-		data->header = hdr;
-		atomic_inc(&hdr->refcnt);
-	} else {
-		if (data != prealloc)
-			kfree(data);
-		data = NULL;
-	}
-out:
-	return data;
+	if (p)
+		p->rw_mode = FMODE_READ;
+	return p;
 }
 
-void nfs_readhdr_free(struct nfs_pgio_header *hdr)
+static void nfs_readhdr_free(struct nfs_pgio_header *rhdr)
 {
-	struct nfs_read_header *rhdr = container_of(hdr, struct nfs_read_header, header);
-
+	kfree(rhdr->res.scratch);
 	kmem_cache_free(nfs_rdata_cachep, rhdr);
 }
-EXPORT_SYMBOL_GPL(nfs_readhdr_free);
 
-void nfs_readdata_release(struct nfs_read_data *rdata)
+static int nfs_return_empty_folio(struct folio *folio)
 {
-	struct nfs_pgio_header *hdr = rdata->header;
-	struct nfs_read_header *read_header = container_of(hdr, struct nfs_read_header, header);
-
-	put_nfs_open_context(rdata->args.context);
-	if (rdata->pages.pagevec != rdata->pages.page_array)
-		kfree(rdata->pages.pagevec);
-	if (rdata == &read_header->rpc_data) {
-		rdata->header = NULL;
-		rdata = NULL;
-	}
-	if (atomic_dec_and_test(&hdr->refcnt))
-		hdr->completion_ops->completion(hdr);
-	/* Note: we only free the rpc_task after callbacks are done.
-	 * See the comment in rpc_free_task() for why
-	 */
-	kfree(rdata);
-}
-EXPORT_SYMBOL_GPL(nfs_readdata_release);
-
-static
-int nfs_return_empty_page(struct page *page)
-{
-	zero_user(page, 0, PAGE_CACHE_SIZE);
-	SetPageUptodate(page);
-	unlock_page(page);
+	folio_zero_segment(folio, 0, folio_size(folio));
+	folio_mark_uptodate(folio);
+	if (nfs_netfs_folio_unlock(folio))
+		folio_unlock(folio);
 	return 0;
 }
 
 void nfs_pageio_init_read(struct nfs_pageio_descriptor *pgio,
-			      struct inode *inode,
+			      struct inode *inode, bool force_mds,
 			      const struct nfs_pgio_completion_ops *compl_ops)
 {
-	nfs_pageio_init(pgio, inode, &nfs_pageio_read_ops, compl_ops,
-			NFS_SERVER(inode)->rsize, 0);
+	struct nfs_server *server = NFS_SERVER(inode);
+	const struct nfs_pageio_ops *pg_ops = &nfs_pgio_rw_ops;
+
+#ifdef CONFIG_NFS_V4_1
+	if (server->pnfs_curr_ld && !force_mds)
+		pg_ops = server->pnfs_curr_ld->pg_read_ops;
+#endif
+	nfs_pageio_init(pgio, inode, pg_ops, compl_ops, &nfs_rw_read_ops,
+			server->rsize, 0);
 }
 EXPORT_SYMBOL_GPL(nfs_pageio_init_read);
 
-void nfs_pageio_reset_read_mds(struct nfs_pageio_descriptor *pgio)
+void nfs_pageio_complete_read(struct nfs_pageio_descriptor *pgio)
 {
-	pgio->pg_ops = &nfs_pageio_read_ops;
-	pgio->pg_bsize = NFS_SERVER(pgio->pg_inode)->rsize;
+	struct nfs_pgio_mirror *pgm;
+	unsigned long npages;
+
+	nfs_pageio_complete(pgio);
+
+	/* It doesn't make sense to do mirrored reads! */
+	WARN_ON_ONCE(pgio->pg_mirror_count != 1);
+
+	pgm = &pgio->pg_mirrors[0];
+	NFS_I(pgio->pg_inode)->read_io += pgm->pg_bytes_written;
+	npages = (pgm->pg_bytes_written + PAGE_SIZE - 1) >> PAGE_SHIFT;
+	nfs_add_stats(pgio->pg_inode, NFSIOS_READPAGES, npages);
 }
-EXPORT_SYMBOL_GPL(nfs_pageio_reset_read_mds);
 
-int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode,
-		       struct page *page)
+
+void nfs_pageio_reset_read_mds(struct nfs_pageio_descriptor *pgio)
 {
-	struct nfs_page	*new;
-	unsigned int len;
-	struct nfs_pageio_descriptor pgio;
+	struct nfs_pgio_mirror *mirror;
 
-	len = nfs_page_length(page);
-	if (len == 0)
-		return nfs_return_empty_page(page);
-	new = nfs_create_request(ctx, inode, page, 0, len);
-	if (IS_ERR(new)) {
-		unlock_page(page);
-		return PTR_ERR(new);
-	}
-	if (len < PAGE_CACHE_SIZE)
-		zero_user_segment(page, len, PAGE_CACHE_SIZE);
+	if (pgio->pg_ops && pgio->pg_ops->pg_cleanup)
+		pgio->pg_ops->pg_cleanup(pgio);
 
-	NFS_PROTO(inode)->read_pageio_init(&pgio, inode, &nfs_async_read_completion_ops);
-	nfs_pageio_add_request(&pgio, new);
-	nfs_pageio_complete(&pgio);
-	NFS_I(inode)->read_io += pgio.pg_bytes_written;
-	return 0;
+	pgio->pg_ops = &nfs_pgio_rw_ops;
+
+	/* read path should never have more than one mirror */
+	WARN_ON_ONCE(pgio->pg_mirror_count != 1);
+
+	mirror = &pgio->pg_mirrors[0];
+	mirror->pg_bsize = NFS_SERVER(pgio->pg_inode)->rsize;
 }
+EXPORT_SYMBOL_GPL(nfs_pageio_reset_read_mds);
 
-static void nfs_readpage_release(struct nfs_page *req)
+bool nfs_read_alloc_scratch(struct nfs_pgio_header *hdr, size_t size)
 {
-	struct inode *d_inode = req->wb_context->dentry->d_inode;
+	WARN_ON(hdr->res.scratch != NULL);
+	hdr->res.scratch = kmalloc(size, GFP_KERNEL);
+	return hdr->res.scratch != NULL;
+}
+EXPORT_SYMBOL_GPL(nfs_read_alloc_scratch);
 
-	if (PageUptodate(req->wb_page))
-		nfs_readpage_to_fscache(d_inode, req->wb_page, 0);
+static void nfs_readpage_release(struct nfs_page *req, int error)
+{
+	struct folio *folio = nfs_page_to_folio(req);
 
-	unlock_page(req->wb_page);
+	if (nfs_page_group_sync_on_bit(req, PG_UNLOCKPAGE))
+		if (nfs_netfs_folio_unlock(folio))
+			folio_unlock(folio);
 
-	dprintk("NFS: read done (%s/%Ld %d@%Ld)\n",
-			req->wb_context->dentry->d_inode->i_sb->s_id,
-			(long long)NFS_FILEID(req->wb_context->dentry->d_inode),
-			req->wb_bytes,
-			(long long)req_offset(req));
 	nfs_release_request(req);
 }
 
-/* Note io was page aligned */
+static void nfs_page_group_set_uptodate(struct nfs_page *req)
+{
+	if (nfs_page_group_sync_on_bit(req, PG_UPTODATE))
+		folio_mark_uptodate(nfs_page_to_folio(req));
+}
+
 static void nfs_read_completion(struct nfs_pgio_header *hdr)
 {
 	unsigned long bytes = 0;
+	int error;
 
 	if (test_bit(NFS_IOHDR_REDO, &hdr->flags))
 		goto out;
 	while (!list_empty(&hdr->pages)) {
 		struct nfs_page *req = nfs_list_entry(hdr->pages.next);
-		struct page *page = req->wb_page;
+		struct folio *folio = nfs_page_to_folio(req);
+		unsigned long start = req->wb_pgbase;
+		unsigned long end = req->wb_pgbase + req->wb_bytes;
 
 		if (test_bit(NFS_IOHDR_EOF, &hdr->flags)) {
-			if (bytes > hdr->good_bytes)
-				zero_user(page, 0, PAGE_SIZE);
-			else if (hdr->good_bytes - bytes < PAGE_SIZE)
-				zero_user_segment(page,
-					hdr->good_bytes & ~PAGE_MASK,
-					PAGE_SIZE);
+			/* note: regions of the page not covered by a
+			 * request are zeroed in nfs_read_add_folio
+			 */
+			if (bytes > hdr->good_bytes) {
+				/* nothing in this request was good, so zero
+				 * the full extent of the request */
+				folio_zero_segment(folio, start, end);
+
+			} else if (hdr->good_bytes - bytes < req->wb_bytes) {
+				/* part of this request has good bytes, but
+				 * not all. zero the bad bytes */
+				start += hdr->good_bytes - bytes;
+				WARN_ON(start < req->wb_pgbase);
+				folio_zero_segment(folio, start, end);
+			}
 		}
+		error = 0;
 		bytes += req->wb_bytes;
 		if (test_bit(NFS_IOHDR_ERROR, &hdr->flags)) {
 			if (bytes <= hdr->good_bytes)
-				SetPageUptodate(page);
+				nfs_page_group_set_uptodate(req);
+			else {
+				error = hdr->error;
+				xchg(&nfs_req_openctx(req)->error, error);
+			}
 		} else
-			SetPageUptodate(page);
+			nfs_page_group_set_uptodate(req);
 		nfs_list_remove_request(req);
-		nfs_readpage_release(req);
+		nfs_readpage_release(req, error);
 	}
+	nfs_netfs_read_completion(hdr);
+
 out:
 	hdr->release(hdr);
 }
 
-int nfs_initiate_read(struct rpc_clnt *clnt,
-		      struct nfs_read_data *data,
-		      const struct rpc_call_ops *call_ops, int flags)
-{
-	struct inode *inode = data->header->inode;
-	int swap_flags = IS_SWAPFILE(inode) ? NFS_RPC_SWAPFLAGS : 0;
-	struct rpc_task *task;
-	struct rpc_message msg = {
-		.rpc_argp = &data->args,
-		.rpc_resp = &data->res,
-		.rpc_cred = data->header->cred,
-	};
-	struct rpc_task_setup task_setup_data = {
-		.task = &data->task,
-		.rpc_client = clnt,
-		.rpc_message = &msg,
-		.callback_ops = call_ops,
-		.callback_data = data,
-		.workqueue = nfsiod_workqueue,
-		.flags = RPC_TASK_ASYNC | swap_flags | flags,
-	};
-
-	/* Set up the initial task struct. */
-	NFS_PROTO(inode)->read_setup(data, &msg);
-
-	dprintk("NFS: %5u initiated read call (req %s/%lld, %u bytes @ "
-			"offset %llu)\n",
-			data->task.tk_pid,
-			inode->i_sb->s_id,
-			(long long)NFS_FILEID(inode),
-			data->args.count,
-			(unsigned long long)data->args.offset);
-
-	task = rpc_run_task(&task_setup_data);
-	if (IS_ERR(task))
-		return PTR_ERR(task);
-	rpc_put_task(task);
-	return 0;
-}
-EXPORT_SYMBOL_GPL(nfs_initiate_read);
-
-/*
- * Set up the NFS read request struct
- */
-static void nfs_read_rpcsetup(struct nfs_read_data *data,
-		unsigned int count, unsigned int offset)
-{
-	struct nfs_page *req = data->header->req;
-
-	data->args.fh     = NFS_FH(data->header->inode);
-	data->args.offset = req_offset(req) + offset;
-	data->args.pgbase = req->wb_pgbase + offset;
-	data->args.pages  = data->pages.pagevec;
-	data->args.count  = count;
-	data->args.context = get_nfs_open_context(req->wb_context);
-	data->args.lock_context = req->wb_lock_context;
-
-	data->res.fattr   = &data->fattr;
-	data->res.count   = count;
-	data->res.eof     = 0;
-	nfs_fattr_init(&data->fattr);
-}
-
-static int nfs_do_read(struct nfs_read_data *data,
-		const struct rpc_call_ops *call_ops)
-{
-	struct inode *inode = data->header->inode;
-
-	return nfs_initiate_read(NFS_CLIENT(inode), data, call_ops, 0);
-}
-
-static int
-nfs_do_multiple_reads(struct list_head *head,
-		const struct rpc_call_ops *call_ops)
+static void nfs_initiate_read(struct nfs_pgio_header *hdr,
+			      struct rpc_message *msg,
+			      const struct nfs_rpc_ops *rpc_ops,
+			      struct rpc_task_setup *task_setup_data, int how)
 {
-	struct nfs_read_data *data;
-	int ret = 0;
-
-	while (!list_empty(head)) {
-		int ret2;
-
-		data = list_first_entry(head, struct nfs_read_data, list);
-		list_del_init(&data->list);
-
-		ret2 = nfs_do_read(data, call_ops);
-		if (ret == 0)
-			ret = ret2;
-	}
-	return ret;
+	rpc_ops->read_setup(hdr, msg);
+	nfs_netfs_initiate_read(hdr);
+	trace_nfs_initiate_read(hdr);
 }
 
 static void
-nfs_async_read_error(struct list_head *head)
+nfs_async_read_error(struct list_head *head, int error)
 {
 	struct nfs_page	*req;
 
 	while (!list_empty(head)) {
 		req = nfs_list_entry(head->next);
 		nfs_list_remove_request(req);
-		nfs_readpage_release(req);
+		nfs_readpage_release(req, error);
 	}
 }
 
-static const struct nfs_pgio_completion_ops nfs_async_read_completion_ops = {
+const struct nfs_pgio_completion_ops nfs_async_read_completion_ops = {
 	.error_cleanup = nfs_async_read_error,
 	.completion = nfs_read_completion,
 };
 
-static void nfs_pagein_error(struct nfs_pageio_descriptor *desc,
-		struct nfs_pgio_header *hdr)
-{
-	set_bit(NFS_IOHDR_REDO, &hdr->flags);
-	while (!list_empty(&hdr->rpc_list)) {
-		struct nfs_read_data *data = list_first_entry(&hdr->rpc_list,
-				struct nfs_read_data, list);
-		list_del(&data->list);
-		nfs_readdata_release(data);
-	}
-	desc->pg_completion_ops->error_cleanup(&desc->pg_list);
-}
-
-/*
- * 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 nfs_pageio_descriptor *desc,
-			    struct nfs_pgio_header *hdr)
-{
-	struct nfs_page *req = hdr->req;
-	struct page *page = req->wb_page;
-	struct nfs_read_data *data;
-	size_t rsize = desc->pg_bsize, nbytes;
-	unsigned int offset;
-
-	offset = 0;
-	nbytes = desc->pg_count;
-	do {
-		size_t len = min(nbytes,rsize);
-
-		data = nfs_readdata_alloc(hdr, 1);
-		if (!data) {
-			nfs_pagein_error(desc, hdr);
-			return -ENOMEM;
-		}
-		data->pages.pagevec[0] = page;
-		nfs_read_rpcsetup(data, len, offset);
-		list_add(&data->list, &hdr->rpc_list);
-		nbytes -= len;
-		offset += len;
-	} while (nbytes != 0);
-
-	nfs_list_remove_request(req);
-	nfs_list_add_request(req, &hdr->pages);
-	desc->pg_rpc_callops = &nfs_read_common_ops;
-	return 0;
-}
-
-static int nfs_pagein_one(struct nfs_pageio_descriptor *desc,
-			  struct nfs_pgio_header *hdr)
-{
-	struct nfs_page		*req;
-	struct page		**pages;
-	struct nfs_read_data    *data;
-	struct list_head *head = &desc->pg_list;
-
-	data = nfs_readdata_alloc(hdr, nfs_page_array_len(desc->pg_base,
-							  desc->pg_count));
-	if (!data) {
-		nfs_pagein_error(desc, hdr);
-		return -ENOMEM;
-	}
-
-	pages = data->pages.pagevec;
-	while (!list_empty(head)) {
-		req = nfs_list_entry(head->next);
-		nfs_list_remove_request(req);
-		nfs_list_add_request(req, &hdr->pages);
-		*pages++ = req->wb_page;
-	}
-
-	nfs_read_rpcsetup(data, desc->pg_count, 0);
-	list_add(&data->list, &hdr->rpc_list);
-	desc->pg_rpc_callops = &nfs_read_common_ops;
-	return 0;
-}
-
-int nfs_generic_pagein(struct nfs_pageio_descriptor *desc,
-		       struct nfs_pgio_header *hdr)
-{
-	if (desc->pg_bsize < PAGE_CACHE_SIZE)
-		return nfs_pagein_multi(desc, hdr);
-	return nfs_pagein_one(desc, hdr);
-}
-EXPORT_SYMBOL_GPL(nfs_generic_pagein);
-
-static int nfs_generic_pg_readpages(struct nfs_pageio_descriptor *desc)
-{
-	struct nfs_read_header *rhdr;
-	struct nfs_pgio_header *hdr;
-	int ret;
-
-	rhdr = nfs_readhdr_alloc();
-	if (!rhdr) {
-		desc->pg_completion_ops->error_cleanup(&desc->pg_list);
-		return -ENOMEM;
-	}
-	hdr = &rhdr->header;
-	nfs_pgheader_init(desc, hdr, nfs_readhdr_free);
-	atomic_inc(&hdr->refcnt);
-	ret = nfs_generic_pagein(desc, hdr);
-	if (ret == 0)
-		ret = nfs_do_multiple_reads(&hdr->rpc_list,
-					    desc->pg_rpc_callops);
-	if (atomic_dec_and_test(&hdr->refcnt))
-		hdr->completion_ops->completion(hdr);
-	return ret;
-}
-
-static const struct nfs_pageio_ops nfs_pageio_read_ops = {
-	.pg_test = nfs_generic_pg_test,
-	.pg_doio = nfs_generic_pg_readpages,
-};
-
 /*
  * This is the callback from RPC telling us whether a reply was
  * received or some error occurred (timeout or socket shutdown).
  */
-int nfs_readpage_result(struct rpc_task *task, struct nfs_read_data *data)
+static int nfs_readpage_done(struct rpc_task *task,
+			     struct nfs_pgio_header *hdr,
+			     struct inode *inode)
 {
-	struct inode *inode = data->header->inode;
-	int status;
-
-	dprintk("NFS: %s: %5u, (status %d)\n", __func__, task->tk_pid,
-			task->tk_status);
-
-	status = NFS_PROTO(inode)->read_done(task, data);
+	int status = NFS_PROTO(inode)->read_done(task, hdr);
 	if (status != 0)
 		return status;
 
-	nfs_add_stats(inode, NFSIOS_SERVERREADBYTES, data->res.count);
+	nfs_add_stats(inode, NFSIOS_SERVERREADBYTES, hdr->res.count);
+	trace_nfs_readpage_done(task, hdr);
 
 	if (task->tk_status == -ESTALE) {
-		set_bit(NFS_INO_STALE, &NFS_I(inode)->flags);
+		nfs_set_inode_stale(inode);
 		nfs_mark_for_revalidate(inode);
 	}
 	return 0;
 }
 
-static void nfs_readpage_retry(struct rpc_task *task, struct nfs_read_data *data)
+static void nfs_readpage_retry(struct rpc_task *task,
+			       struct nfs_pgio_header *hdr)
 {
-	struct nfs_readargs *argp = &data->args;
-	struct nfs_readres *resp = &data->res;
+	struct nfs_pgio_args *argp = &hdr->args;
+	struct nfs_pgio_res  *resp = &hdr->res;
 
 	/* This is a short read! */
-	nfs_inc_stats(data->header->inode, NFSIOS_SHORTREAD);
+	nfs_inc_stats(hdr->inode, NFSIOS_SHORTREAD);
+	trace_nfs_readpage_short(task, hdr);
+
 	/* Has the server at least made some progress? */
 	if (resp->count == 0) {
-		nfs_set_pgio_error(data->header, -EIO, argp->offset);
+		nfs_set_pgio_error(hdr, -EIO, argp->offset);
 		return;
 	}
-	/* Yes, so retry the read at the end of the data */
-	data->mds_offset += resp->count;
+
+	/* For non rpc-based layout drivers, retry-through-MDS */
+	if (!task->tk_ops) {
+		hdr->pnfs_error = -EAGAIN;
+		return;
+	}
+
+	/* Yes, so retry the read at the end of the hdr */
+	hdr->mds_offset += resp->count;
 	argp->offset += resp->count;
 	argp->pgbase += resp->count;
 	argp->count -= resp->count;
+	resp->count = 0;
+	resp->eof = 0;
 	rpc_restart_call_prepare(task);
 }
 
-static void nfs_readpage_result_common(struct rpc_task *task, void *calldata)
+static void nfs_readpage_result(struct rpc_task *task,
+				struct nfs_pgio_header *hdr)
 {
-	struct nfs_read_data *data = calldata;
-	struct nfs_pgio_header *hdr = data->header;
+	if (hdr->res.eof) {
+		loff_t pos = hdr->args.offset + hdr->res.count;
+		unsigned int new = pos - hdr->io_start;
 
-	/* Note the only returns of nfs_readpage_result are 0 and -EAGAIN */
-	if (nfs_readpage_result(task, data) != 0)
-		return;
-	if (task->tk_status < 0)
-		nfs_set_pgio_error(hdr, task->tk_status, data->args.offset);
-	else if (data->res.eof) {
-		loff_t bound;
-
-		bound = data->args.offset + data->res.count;
-		spin_lock(&hdr->lock);
-		if (bound < hdr->io_start + hdr->good_bytes) {
+		if (hdr->good_bytes > new) {
+			hdr->good_bytes = new;
 			set_bit(NFS_IOHDR_EOF, &hdr->flags);
 			clear_bit(NFS_IOHDR_ERROR, &hdr->flags);
-			hdr->good_bytes = bound - hdr->io_start;
 		}
-		spin_unlock(&hdr->lock);
-	} else if (data->res.count != data->args.count)
-		nfs_readpage_retry(task, data);
+	} else if (hdr->res.count < hdr->args.count)
+		nfs_readpage_retry(task, hdr);
 }
 
-static void nfs_readpage_release_common(void *calldata)
+int nfs_read_add_folio(struct nfs_pageio_descriptor *pgio,
+		       struct nfs_open_context *ctx,
+		       struct folio *folio)
 {
-	nfs_readdata_release(calldata);
+	struct inode *inode = folio->mapping->host;
+	struct nfs_server *server = NFS_SERVER(inode);
+	size_t fsize = folio_size(folio);
+	unsigned int rsize = server->rsize;
+	struct nfs_page *new;
+	unsigned int len, aligned_len;
+	int error;
+
+	len = nfs_folio_length(folio);
+	if (len == 0)
+		return nfs_return_empty_folio(folio);
+
+	aligned_len = min_t(unsigned int, ALIGN(len, rsize), fsize);
+
+	new = nfs_page_create_from_folio(ctx, folio, 0, aligned_len);
+	if (IS_ERR(new)) {
+		error = PTR_ERR(new);
+		if (nfs_netfs_folio_unlock(folio))
+			folio_unlock(folio);
+		goto out;
+	}
+
+	if (len < fsize)
+		folio_zero_segment(folio, len, fsize);
+	if (!nfs_pageio_add_request(pgio, new)) {
+		nfs_list_remove_request(new);
+		error = pgio->pg_error;
+		nfs_readpage_release(new, error);
+		goto out;
+	}
+	return 0;
+out:
+	return error;
 }
 
-void nfs_read_prepare(struct rpc_task *task, void *calldata)
+/*
+ * Actually read a folio over the wire.
+ */
+static int nfs_do_read_folio(struct file *file, struct folio *folio)
 {
-	struct nfs_read_data *data = calldata;
-	NFS_PROTO(data->header->inode)->read_rpc_prepare(task, data);
-	if (unlikely(test_bit(NFS_CONTEXT_BAD, &data->args.context->flags)))
-		rpc_exit(task, -EIO);
-}
+	struct inode *inode = file_inode(file);
+	struct nfs_pageio_descriptor pgio;
+	struct nfs_open_context *ctx;
+	int ret;
 
-static const struct rpc_call_ops nfs_read_common_ops = {
-	.rpc_call_prepare = nfs_read_prepare,
-	.rpc_call_done = nfs_readpage_result_common,
-	.rpc_release = nfs_readpage_release_common,
-};
+	ctx = get_nfs_open_context(nfs_file_open_context(file));
+
+	xchg(&ctx->error, 0);
+	nfs_pageio_init_read(&pgio, inode, false,
+			     &nfs_async_read_completion_ops);
+
+	ret = nfs_read_add_folio(&pgio, ctx, folio);
+	if (ret)
+		goto out_put;
+
+	nfs_pageio_complete_read(&pgio);
+	nfs_update_delegated_atime(inode);
+	if (pgio.pg_error < 0) {
+		ret = pgio.pg_error;
+		goto out_put;
+	}
+
+	ret = folio_wait_locked_killable(folio);
+	if (!folio_test_uptodate(folio) && !ret)
+		ret = xchg(&ctx->error, 0);
+
+out_put:
+	put_nfs_open_context(ctx);
+	return ret;
+}
 
 /*
- * Read a page over NFS.
- * 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.
+ * Synchronously read a folio.
+ *
+ * This is not heavily used as most users to try an asynchronous
+ * large read through ->readahead first.
  */
-int nfs_readpage(struct file *file, struct page *page)
+int nfs_read_folio(struct file *file, struct folio *folio)
 {
-	struct nfs_open_context *ctx;
-	struct inode *inode = page_file_mapping(page)->host;
-	int		error;
+	struct inode *inode = file_inode(file);
+	loff_t pos = folio_pos(folio);
+	size_t len = folio_size(folio);
+	int ret;
 
-	dprintk("NFS: nfs_readpage (%p %ld@%lu)\n",
-		page, PAGE_CACHE_SIZE, page_file_index(page));
+	trace_nfs_aop_readpage(inode, pos, len);
 	nfs_inc_stats(inode, NFSIOS_VFSREADPAGE);
-	nfs_add_stats(inode, NFSIOS_READPAGES, 1);
+	task_io_account_read(len);
 
 	/*
 	 * Try to flush any pending writes to the file..
 	 *
-	 * NOTE! Because we own the page lock, there cannot
+	 * NOTE! Because we own the folio lock, there cannot
 	 * be any new pending writes generated at this point
-	 * for this page (other pages can be written to).
+	 * for this folio (other folios can be written to).
 	 */
-	error = nfs_wb_page(inode, page);
-	if (error)
+	ret = nfs_wb_folio(inode, folio);
+	if (ret)
 		goto out_unlock;
-	if (PageUptodate(page))
+	if (folio_test_uptodate(folio))
 		goto out_unlock;
 
-	error = -ESTALE;
+	ret = -ESTALE;
 	if (NFS_STALE(inode))
 		goto out_unlock;
 
-	if (file == NULL) {
-		error = -EBADF;
-		ctx = nfs_find_open_context(inode, NULL, FMODE_READ);
-		if (ctx == NULL)
-			goto out_unlock;
-	} else
-		ctx = get_nfs_open_context(nfs_file_open_context(file));
-
-	if (!IS_SYNC(inode)) {
-		error = nfs_readpage_from_fscache(ctx, inode, page);
-		if (error == 0)
-			goto out;
-	}
-
-	error = nfs_readpage_async(ctx, inode, page);
-
+	ret = nfs_netfs_read_folio(file, folio);
+	if (ret)
+		ret = nfs_do_read_folio(file, folio);
 out:
-	put_nfs_open_context(ctx);
-	return error;
-out_unlock:
-	unlock_page(page);
-	return error;
-}
-
-struct nfs_readdesc {
-	struct nfs_pageio_descriptor *pgio;
-	struct nfs_open_context *ctx;
-};
-
-static int
-readpage_async_filler(void *data, struct page *page)
-{
-	struct nfs_readdesc *desc = (struct nfs_readdesc *)data;
-	struct inode *inode = page_file_mapping(page)->host;
-	struct nfs_page *new;
-	unsigned int len;
-	int error;
-
-	len = nfs_page_length(page);
-	if (len == 0)
-		return nfs_return_empty_page(page);
-
-	new = nfs_create_request(desc->ctx, inode, page, 0, len);
-	if (IS_ERR(new))
-		goto out_error;
-
-	if (len < PAGE_CACHE_SIZE)
-		zero_user_segment(page, len, PAGE_CACHE_SIZE);
-	if (!nfs_pageio_add_request(desc->pgio, new)) {
-		error = desc->pgio->pg_error;
-		goto out_unlock;
-	}
-	return 0;
-out_error:
-	error = PTR_ERR(new);
+	trace_nfs_aop_readpage_done(inode, pos, len, ret);
+	return ret;
 out_unlock:
-	unlock_page(page);
-	return error;
+	folio_unlock(folio);
+	goto out;
 }
 
-int nfs_readpages(struct file *filp, struct address_space *mapping,
-		struct list_head *pages, unsigned nr_pages)
+void nfs_readahead(struct readahead_control *ractl)
 {
 	struct nfs_pageio_descriptor pgio;
-	struct nfs_readdesc desc = {
-		.pgio = &pgio,
-	};
-	struct inode *inode = mapping->host;
-	unsigned long npages;
-	int ret = -ESTALE;
+	struct nfs_open_context *ctx;
+	unsigned int nr_pages = readahead_count(ractl);
+	struct file *file = ractl->file;
+	struct inode *inode = ractl->mapping->host;
+	struct folio *folio;
+	int ret;
 
-	dprintk("NFS: nfs_readpages (%s/%Ld %d)\n",
-			inode->i_sb->s_id,
-			(long long)NFS_FILEID(inode),
-			nr_pages);
+	trace_nfs_aop_readahead(inode, readahead_pos(ractl), nr_pages);
 	nfs_inc_stats(inode, NFSIOS_VFSREADPAGES);
+	task_io_account_read(readahead_length(ractl));
 
+	ret = -ESTALE;
 	if (NFS_STALE(inode))
 		goto out;
 
-	if (filp == NULL) {
-		desc.ctx = nfs_find_open_context(inode, NULL, FMODE_READ);
-		if (desc.ctx == NULL)
-			return -EBADF;
+	ret = nfs_netfs_readahead(ractl);
+	if (!ret)
+		goto out;
+
+	if (file == NULL) {
+		ret = -EBADF;
+		ctx = nfs_find_open_context(inode, NULL, FMODE_READ);
+		if (ctx == NULL)
+			goto out;
 	} else
-		desc.ctx = get_nfs_open_context(nfs_file_open_context(filp));
+		ctx = get_nfs_open_context(nfs_file_open_context(file));
 
-	/* attempt to read as many of the pages as possible from the cache
-	 * - this returns -ENOBUFS immediately if the cookie is negative
-	 */
-	ret = nfs_readpages_from_fscache(desc.ctx, inode, mapping,
-					 pages, &nr_pages);
-	if (ret == 0)
-		goto read_complete; /* all pages were read */
+	nfs_pageio_init_read(&pgio, inode, false,
+			     &nfs_async_read_completion_ops);
 
-	NFS_PROTO(inode)->read_pageio_init(&pgio, inode, &nfs_async_read_completion_ops);
+	while ((folio = readahead_folio(ractl)) != NULL) {
+		ret = nfs_read_add_folio(&pgio, ctx, folio);
+		if (ret)
+			break;
+	}
 
-	ret = read_cache_pages(mapping, pages, readpage_async_filler, &desc);
+	nfs_pageio_complete_read(&pgio);
+	nfs_update_delegated_atime(inode);
 
-	nfs_pageio_complete(&pgio);
-	NFS_I(inode)->read_io += pgio.pg_bytes_written;
-	npages = (pgio.pg_bytes_written + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
-	nfs_add_stats(inode, NFSIOS_READPAGES, npages);
-read_complete:
-	put_nfs_open_context(desc.ctx);
+	put_nfs_open_context(ctx);
 out:
-	return ret;
+	trace_nfs_aop_readahead_done(inode, nr_pages, ret);
 }
 
 int __init nfs_init_readpagecache(void)
 {
 	nfs_rdata_cachep = kmem_cache_create("nfs_read_data",
-					     sizeof(struct nfs_read_header),
+					     sizeof(struct nfs_pgio_header),
 					     0, SLAB_HWCACHE_ALIGN,
 					     NULL);
 	if (nfs_rdata_cachep == NULL)
@@ -683,3 +466,11 @@ void nfs_destroy_readpagecache(void)
 {
 	kmem_cache_destroy(nfs_rdata_cachep);
 }
+
+static const struct nfs_rw_ops nfs_rw_read_ops = {
+	.rw_alloc_header	= nfs_readhdr_alloc,
+	.rw_free_header		= nfs_readhdr_free,
+	.rw_done		= nfs_readpage_done,
+	.rw_result		= nfs_readpage_result,
+	.rw_initiate		= nfs_initiate_read,
+};