NFS: Convert buffered writes to use folios

Mostly mechanical conversion of struct page and functions into struct
folio equivalents.
The lack of support for folios in write_cache_pages(), means we still
only support order 0 folio allocations. However the rest of the
writeback code should now be ready for order n > 0.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

fs/nfs/file.c

@@ -319,6 +319,7 @@ static int nfs_write_begin(struct file *file, struct address_space *mapping,
 	int ret;
 	pgoff_t index = pos >> PAGE_SHIFT;
 	struct page *page;
+	struct folio *folio;
 	int once_thru = 0;
 
 	dfprintk(PAGECACHE, "NFS: write_begin(%pD2(%lu), %u@%lld)\n",
@@ -329,15 +330,16 @@ static int nfs_write_begin(struct file *file, struct address_space *mapping,
 	if (!page)
 		return -ENOMEM;
 	*pagep = page;
+	folio = page_folio(page);
 
-	ret = nfs_flush_incompatible(file, page);
+	ret = nfs_flush_incompatible(file, folio);
 	if (ret) {
 		unlock_page(page);
 		put_page(page);
 	} else if (!once_thru &&
 		   nfs_want_read_modify_write(file, page, pos, len)) {
 		once_thru = 1;
-		ret = nfs_read_folio(file, page_folio(page));
+		ret = nfs_read_folio(file, folio);
 		put_page(page);
 		if (!ret)
 			goto start;
@@ -351,6 +353,7 @@ static int nfs_write_end(struct file *file, struct address_space *mapping,
 {
 	unsigned offset = pos & (PAGE_SIZE - 1);
 	struct nfs_open_context *ctx = nfs_file_open_context(file);
+	struct folio *folio = page_folio(page);
 	int status;
 
 	dfprintk(PAGECACHE, "NFS: write_end(%pD2(%lu), %u@%lld)\n",
@@ -376,7 +379,7 @@ static int nfs_write_end(struct file *file, struct address_space *mapping,
 			zero_user_segment(page, pglen, PAGE_SIZE);
 	}
 
-	status = nfs_updatepage(file, page, offset, copied);
+	status = nfs_update_folio(file, folio, offset, copied);
 
 	unlock_page(page);
 	put_page(page);
@@ -552,6 +555,7 @@ static vm_fault_t nfs_vm_page_mkwrite(struct vm_fault *vmf)
 	unsigned pagelen;
 	vm_fault_t ret = VM_FAULT_NOPAGE;
 	struct address_space *mapping;
+	struct folio *folio = page_folio(page);
 
 	dfprintk(PAGECACHE, "NFS: vm_page_mkwrite(%pD2(%lu), offset %lld)\n",
 		filp, filp->f_mapping->host->i_ino,
@@ -582,8 +586,8 @@ static vm_fault_t nfs_vm_page_mkwrite(struct vm_fault *vmf)
 		goto out_unlock;
 
 	ret = VM_FAULT_LOCKED;
-	if (nfs_flush_incompatible(filp, page) == 0 &&
-	    nfs_updatepage(filp, page, 0, pagelen) == 0)
+	if (nfs_flush_incompatible(filp, folio) == 0 &&
+	    nfs_update_folio(filp, folio, 0, pagelen) == 0)
 		goto out;
 
 	ret = VM_FAULT_SIGBUS;

fs/nfs/internal.h

@@ -760,17 +760,18 @@ void nfs_super_set_maxbytes(struct super_block *sb, __u64 maxfilesize)
  * Record the page as unstable (an extra writeback period) and mark its
  * inode as dirty.
  */
-static inline
-void nfs_mark_page_unstable(struct page *page, struct nfs_commit_info *cinfo)
+static inline void nfs_folio_mark_unstable(struct folio *folio,
+					   struct nfs_commit_info *cinfo)
 {
-	if (!cinfo->dreq) {
-		struct inode *inode = page_file_mapping(page)->host;
+	if (folio && !cinfo->dreq) {
+		struct inode *inode = folio_file_mapping(folio)->host;
+		long nr = folio_nr_pages(folio);
 
 		/* This page is really still in write-back - just that the
 		 * writeback is happening on the server now.
 		 */
-		inc_node_page_state(page, NR_WRITEBACK);
-		inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
+		node_stat_mod_folio(folio, NR_WRITEBACK, nr);
+		wb_stat_mod(&inode_to_bdi(inode)->wb, WB_WRITEBACK, nr);
 		__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 	}
 }

fs/nfs/pnfs.h

@@ -193,7 +193,7 @@ struct pnfs_commit_ops {
 	void (*recover_commit_reqs) (struct list_head *list,
 				     struct nfs_commit_info *cinfo);
 	struct nfs_page * (*search_commit_reqs)(struct nfs_commit_info *cinfo,
-						struct page *page);
+						struct folio *folio);
 };
 
 struct pnfs_layout_hdr {
@@ -395,7 +395,7 @@ void pnfs_generic_rw_release(void *data);
 void pnfs_generic_recover_commit_reqs(struct list_head *dst,
 				      struct nfs_commit_info *cinfo);
 struct nfs_page *pnfs_generic_search_commit_reqs(struct nfs_commit_info *cinfo,
-						 struct page *page);
+						 struct folio *folio);
 int pnfs_generic_commit_pagelist(struct inode *inode,
 				 struct list_head *mds_pages,
 				 int how,
@@ -557,13 +557,13 @@ pnfs_recover_commit_reqs(struct list_head *head, struct nfs_commit_info *cinfo)
 
 static inline struct nfs_page *
 pnfs_search_commit_reqs(struct inode *inode, struct nfs_commit_info *cinfo,
-			struct page *page)
+			struct folio *folio)
 {
 	struct pnfs_ds_commit_info *fl_cinfo = cinfo->ds;
 
 	if (!fl_cinfo->ops || !fl_cinfo->ops->search_commit_reqs)
 		return NULL;
-	return fl_cinfo->ops->search_commit_reqs(cinfo, page);
+	return fl_cinfo->ops->search_commit_reqs(cinfo, folio);
 }
 
 /* Should the pNFS client commit and return the layout upon a setattr */
@@ -864,7 +864,7 @@ pnfs_recover_commit_reqs(struct list_head *head, struct nfs_commit_info *cinfo)
 
 static inline struct nfs_page *
 pnfs_search_commit_reqs(struct inode *inode, struct nfs_commit_info *cinfo,
-			struct page *page)
+			struct folio *folio)
 {
 	return NULL;
 }

fs/nfs/pnfs_nfs.c

@@ -353,7 +353,7 @@ EXPORT_SYMBOL_GPL(pnfs_generic_recover_commit_reqs);
 
 static struct nfs_page *
 pnfs_bucket_search_commit_reqs(struct pnfs_commit_bucket *buckets,
-		unsigned int nbuckets, struct page *page)
+			       unsigned int nbuckets, struct folio *folio)
 {
 	struct nfs_page *req;
 	struct pnfs_commit_bucket *b;
@@ -363,11 +363,11 @@ pnfs_bucket_search_commit_reqs(struct pnfs_commit_bucket *buckets,
 	 * request is found */
 	for (i = 0, b = buckets; i < nbuckets; i++, b++) {
 		list_for_each_entry(req, &b->written, wb_list) {
-			if (req->wb_page == page)
+			if (nfs_page_to_folio(req) == folio)
 				return req->wb_head;
 		}
 		list_for_each_entry(req, &b->committing, wb_list) {
-			if (req->wb_page == page)
+			if (nfs_page_to_folio(req) == folio)
 				return req->wb_head;
 		}
 	}
@@ -375,14 +375,14 @@ pnfs_bucket_search_commit_reqs(struct pnfs_commit_bucket *buckets,
 }
 
 /* pnfs_generic_search_commit_reqs - Search lists in @cinfo for the head request
- *				   for @page
+ *				   for @folio
  * @cinfo - commit info for current inode
- * @page - page to search for matching head request
+ * @folio - page to search for matching head request
  *
  * Return: the head request if one is found, otherwise %NULL.
  */
-struct nfs_page *
-pnfs_generic_search_commit_reqs(struct nfs_commit_info *cinfo, struct page *page)
+struct nfs_page *pnfs_generic_search_commit_reqs(struct nfs_commit_info *cinfo,
+						 struct folio *folio)
 {
 	struct pnfs_ds_commit_info *fl_cinfo = cinfo->ds;
 	struct pnfs_commit_array *array;
@@ -390,7 +390,7 @@ pnfs_generic_search_commit_reqs(struct nfs_commit_info *cinfo, struct page *page
 
 	list_for_each_entry(array, &fl_cinfo->commits, cinfo_list) {
 		req = pnfs_bucket_search_commit_reqs(array->buckets,
-				array->nbuckets, page);
+						     array->nbuckets, folio);
 		if (req)
 			return req;
 	}
@@ -1180,7 +1180,7 @@ pnfs_layout_mark_request_commit(struct nfs_page *req,
 
 	nfs_request_add_commit_list_locked(req, list, cinfo);
 	mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
-	nfs_mark_page_unstable(req->wb_page, cinfo);
+	nfs_folio_mark_unstable(nfs_page_to_folio(req), cinfo);
 	return;
 out_resched:
 	mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);

include/linux/nfs_fs.h

@@ -569,8 +569,9 @@ extern void nfs_complete_unlink(struct dentry *dentry, struct inode *);
 extern int  nfs_congestion_kb;
 extern int  nfs_writepage(struct page *page, struct writeback_control *wbc);
 extern int  nfs_writepages(struct address_space *, struct writeback_control *);
-extern int  nfs_flush_incompatible(struct file *file, struct page *page);
-extern int  nfs_updatepage(struct file *, struct page *, unsigned int, unsigned int);
+extern int  nfs_flush_incompatible(struct file *file, struct folio *folio);
+extern int  nfs_update_folio(struct file *file, struct folio *folio,
+			     unsigned int offset, unsigned int count);
 
 /*
  * Try to write back everything synchronously (but check the