Merge tag 'netfs-folio-20211111' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull netfs, 9p, afs and ceph (partial) foliation from David Howells:
 "This converts netfslib, 9p and afs to use folios. It also partially
  converts ceph so that it uses folios on the boundaries with netfslib.

  To help with this, a couple of folio helper functions are added in the
  first two patches.

  These patches don't touch fscache and cachefiles as I intend to remove
  all the code that deals with pages directly from there. Only nfs and
  cifs are using the old fscache I/O API now. The new API uses iov_iter
  instead.

  Thanks to Jeff Layton, Dominique Martinet and AuriStor for testing and
  retesting the patches"

* tag 'netfs-folio-20211111' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  afs: Use folios in directory handling
  netfs, 9p, afs, ceph: Use folios
  folio: Add a function to get the host inode for a folio
  folio: Add a function to change the private data attached to a folio

2 files changed, 39 insertions, 6 deletions

diff --git a/include/linux/netfs.h b/include/linux/netfs.h
index 12c4177f7703..ca0683b9e3d1 100644
--- a/include/linux/netfs.h
+++ b/include/linux/netfs.h
@@ -166,13 +166,13 @@ struct netfs_read_request {
 	short			error;		/* 0 or error that occurred */
 	loff_t			i_size;		/* Size of the file */
 	loff_t			start;		/* Start position */
-	pgoff_t			no_unlock_page;	/* Don't unlock this page after read */
+	pgoff_t			no_unlock_folio; /* Don't unlock this folio after read */
 	refcount_t		usage;
 	unsigned long		flags;
 #define NETFS_RREQ_INCOMPLETE_IO	0	/* Some ioreqs terminated short or with error */
 #define NETFS_RREQ_WRITE_TO_CACHE	1	/* Need to write to the cache */
-#define NETFS_RREQ_NO_UNLOCK_PAGE	2	/* Don't unlock no_unlock_page on completion */
-#define NETFS_RREQ_DONT_UNLOCK_PAGES	3	/* Don't unlock the pages on completion */
+#define NETFS_RREQ_NO_UNLOCK_FOLIO	2	/* Don't unlock no_unlock_folio on completion */
+#define NETFS_RREQ_DONT_UNLOCK_FOLIOS	3	/* Don't unlock the folios on completion */
 #define NETFS_RREQ_FAILED		4	/* The request failed */
 #define NETFS_RREQ_IN_PROGRESS		5	/* Unlocked when the request completes */
 	const struct netfs_read_request_ops *netfs_ops;
@@ -190,7 +190,7 @@ struct netfs_read_request_ops {
 	void (*issue_op)(struct netfs_read_subrequest *subreq);
 	bool (*is_still_valid)(struct netfs_read_request *rreq);
 	int (*check_write_begin)(struct file *file, loff_t pos, unsigned len,
-				 struct page *page, void **_fsdata);
+				 struct folio *folio, void **_fsdata);
 	void (*done)(struct netfs_read_request *rreq);
 	void (*cleanup)(struct address_space *mapping, void *netfs_priv);
 };
@@ -240,11 +240,11 @@ extern void netfs_readahead(struct readahead_control *,
 			    const struct netfs_read_request_ops *,
 			    void *);
 extern int netfs_readpage(struct file *,
-			  struct page *,
+			  struct folio *,
 			  const struct netfs_read_request_ops *,
 			  void *);
 extern int netfs_write_begin(struct file *, struct address_space *,
-			     loff_t, unsigned int, unsigned int, struct page **,
+			     loff_t, unsigned int, unsigned int, struct folio **,
 			     void **,
 			     const struct netfs_read_request_ops *,
 			     void *);
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 6a30916b76e5..1a0c646eb6ff 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -253,6 +253,20 @@ static inline struct address_space *page_mapping_file(struct page *page)
 	return folio_mapping(folio);
 }
 
+/**
+ * folio_inode - Get the host inode for this folio.
+ * @folio: The folio.
+ *
+ * For folios which are in the page cache, return the inode that this folio
+ * belongs to.
+ *
+ * Do not call this for folios which aren't in the page cache.
+ */
+static inline struct inode *folio_inode(struct folio *folio)
+{
+	return folio->mapping->host;
+}
+
 static inline bool page_cache_add_speculative(struct page *page, int count)
 {
 	VM_BUG_ON_PAGE(PageTail(page), page);
@@ -280,6 +294,25 @@ static inline void folio_attach_private(struct folio *folio, void *data)
 }
 
 /**
+ * folio_change_private - Change private data on a folio.
+ * @folio: Folio to change the data on.
+ * @data: Data to set on the folio.
+ *
+ * Change the private data attached to a folio and return the old
+ * data.  The page must previously have had data attached and the data
+ * must be detached before the folio will be freed.
+ *
+ * Return: Data that was previously attached to the folio.
+ */
+static inline void *folio_change_private(struct folio *folio, void *data)
+{
+	void *old = folio_get_private(folio);
+
+	folio->private = data;
+	return old;
+}
+
+/**
  * folio_detach_private - Detach private data from a folio.
  * @folio: Folio to detach data from.
  *