Merge tag 'folio-5.19' of git://git.infradead.org/users/willy/pagecache

Pull page cache updates from Matthew Wilcox:

 - Appoint myself page cache maintainer

 - Fix how scsicam uses the page cache

 - Use the memalloc_nofs_save() API to replace AOP_FLAG_NOFS

 - Remove the AOP flags entirely

 - Remove pagecache_write_begin() and pagecache_write_end()

 - Documentation updates

 - Convert several address_space operations to use folios:
     - is_dirty_writeback
     - readpage becomes read_folio
     - releasepage becomes release_folio
     - freepage becomes free_folio

 - Change filler_t to require a struct file pointer be the first
   argument like ->read_folio

* tag 'folio-5.19' of git://git.infradead.org/users/willy/pagecache: (107 commits)
  nilfs2: Fix some kernel-doc comments
  Appoint myself page cache maintainer
  fs: Remove aops->freepage
  secretmem: Convert to free_folio
  nfs: Convert to free_folio
  orangefs: Convert to free_folio
  fs: Add free_folio address space operation
  fs: Convert drop_buffers() to use a folio
  fs: Change try_to_free_buffers() to take a folio
  jbd2: Convert release_buffer_page() to use a folio
  jbd2: Convert jbd2_journal_try_to_free_buffers to take a folio
  reiserfs: Convert release_buffer_page() to use a folio
  fs: Remove last vestiges of releasepage
  ubifs: Convert to release_folio
  reiserfs: Convert to release_folio
  orangefs: Convert to release_folio
  ocfs2: Convert to release_folio
  nilfs2: Remove comment about releasepage
  nfs: Convert to release_folio
  jfs: Convert to release_folio
  ...

9 files changed, 85 insertions, 55 deletions

diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h
index bcb4fe9b8575..c9d1463bb20f 100644
--- a/include/linux/buffer_head.h
+++ b/include/linux/buffer_head.h
@@ -146,7 +146,7 @@ BUFFER_FNS(Defer_Completion, defer_completion)
 #define page_has_buffers(page)	PagePrivate(page)
 #define folio_buffers(folio)		folio_get_private(folio)
 
-void buffer_check_dirty_writeback(struct page *page,
+void buffer_check_dirty_writeback(struct folio *folio,
 				     bool *dirty, bool *writeback);
 
 /*
@@ -158,7 +158,7 @@ void mark_buffer_write_io_error(struct buffer_head *bh);
 void touch_buffer(struct buffer_head *bh);
 void set_bh_page(struct buffer_head *bh,
 		struct page *page, unsigned long offset);
-int try_to_free_buffers(struct page *);
+bool try_to_free_buffers(struct folio *);
 struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size,
 		bool retry);
 void create_empty_buffers(struct page *, unsigned long,
@@ -223,10 +223,10 @@ int block_write_full_page(struct page *page, get_block_t *get_block,
 int __block_write_full_page(struct inode *inode, struct page *page,
 			get_block_t *get_block, struct writeback_control *wbc,
 			bh_end_io_t *handler);
-int block_read_full_page(struct page*, get_block_t*);
+int block_read_full_folio(struct folio *, get_block_t *);
 bool block_is_partially_uptodate(struct folio *, size_t from, size_t count);
 int block_write_begin(struct address_space *mapping, loff_t pos, unsigned len,
-		unsigned flags, struct page **pagep, get_block_t *get_block);
+		struct page **pagep, get_block_t *get_block);
 int __block_write_begin(struct page *page, loff_t pos, unsigned len,
 		get_block_t *get_block);
 int block_write_end(struct file *, struct address_space *,
@@ -238,7 +238,7 @@ int generic_write_end(struct file *, struct address_space *,
 void page_zero_new_buffers(struct page *page, unsigned from, unsigned to);
 void clean_page_buffers(struct page *page);
 int cont_write_begin(struct file *, struct address_space *, loff_t,
-			unsigned, unsigned, struct page **, void **,
+			unsigned, struct page **, void **,
 			get_block_t *, loff_t *);
 int generic_cont_expand_simple(struct inode *inode, loff_t size);
 int block_commit_write(struct page *page, unsigned from, unsigned to);
@@ -258,7 +258,7 @@ static inline vm_fault_t block_page_mkwrite_return(int err)
 }
 sector_t generic_block_bmap(struct address_space *, sector_t, get_block_t *);
 int block_truncate_page(struct address_space *, loff_t, get_block_t *);
-int nobh_write_begin(struct address_space *, loff_t, unsigned, unsigned,
+int nobh_write_begin(struct address_space *, loff_t, unsigned len,
 				struct page **, void **, get_block_t*);
 int nobh_write_end(struct file *, struct address_space *,
 				loff_t, unsigned, unsigned,
@@ -402,7 +402,7 @@ bool block_dirty_folio(struct address_space *mapping, struct folio *folio);
 #else /* CONFIG_BLOCK */
 
 static inline void buffer_init(void) {}
-static inline int try_to_free_buffers(struct page *page) { return 1; }
+static inline bool try_to_free_buffers(struct folio *folio) { return true; }
 static inline int inode_has_buffers(struct inode *inode) { return 0; }
 static inline void invalidate_inode_buffers(struct inode *inode) {}
 static inline int remove_inode_buffers(struct inode *inode) { return 1; }
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 02e7f60638b8..f58ae40235ab 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -262,7 +262,7 @@ struct iattr {
  *  			trying again.  The aop will be taking reasonable
  *  			precautions not to livelock.  If the caller held a page
  *  			reference, it should drop it before retrying.  Returned
- *  			by readpage().
+ *  			by read_folio().
  *
  * address_space_operation functions return these large constants to indicate
  * special semantics to the caller.  These are much larger than the bytes in a
@@ -275,10 +275,6 @@ enum positive_aop_returns {
 	AOP_TRUNCATED_PAGE	= 0x80001,
 };
 
-#define AOP_FLAG_NOFS			0x0002 /* used by filesystem to direct
-						* helper code (eg buffer layer)
-						* to clear GFP_FS from alloc */
-
 /*
  * oh the beauties of C type declarations.
  */
@@ -339,7 +335,7 @@ static inline bool is_sync_kiocb(struct kiocb *kiocb)
 
 struct address_space_operations {
 	int (*writepage)(struct page *page, struct writeback_control *wbc);
-	int (*readpage)(struct file *, struct page *);
+	int (*read_folio)(struct file *, struct folio *);
 
 	/* Write back some dirty pages from this mapping. */
 	int (*writepages)(struct address_space *, struct writeback_control *);
@@ -350,7 +346,7 @@ struct address_space_operations {
 	void (*readahead)(struct readahead_control *);
 
 	int (*write_begin)(struct file *, struct address_space *mapping,
-				loff_t pos, unsigned len, unsigned flags,
+				loff_t pos, unsigned len,
 				struct page **pagep, void **fsdata);
 	int (*write_end)(struct file *, struct address_space *mapping,
 				loff_t pos, unsigned len, unsigned copied,
@@ -359,8 +355,8 @@ struct address_space_operations {
 	/* Unfortunately this kludge is needed for FIBMAP. Don't use it */
 	sector_t (*bmap)(struct address_space *, sector_t);
 	void (*invalidate_folio) (struct folio *, size_t offset, size_t len);
-	int (*releasepage) (struct page *, gfp_t);
-	void (*freepage)(struct page *);
+	bool (*release_folio)(struct folio *, gfp_t);
+	void (*free_folio)(struct folio *folio);
 	ssize_t (*direct_IO)(struct kiocb *, struct iov_iter *iter);
 	/*
 	 * migrate the contents of a page to the specified target. If
@@ -373,7 +369,7 @@ struct address_space_operations {
 	int (*launder_folio)(struct folio *);
 	bool (*is_partially_uptodate) (struct folio *, size_t from,
 			size_t count);
-	void (*is_dirty_writeback) (struct page *, bool *, bool *);
+	void (*is_dirty_writeback) (struct folio *, bool *dirty, bool *wb);
 	int (*error_remove_page)(struct address_space *, struct page *);
 
 	/* swapfile support */
@@ -384,18 +380,6 @@ struct address_space_operations {
 
 extern const struct address_space_operations empty_aops;
 
-/*
- * pagecache_write_begin/pagecache_write_end must be used by general code
- * to write into the pagecache.
- */
-int pagecache_write_begin(struct file *, struct address_space *mapping,
-				loff_t pos, unsigned len, unsigned flags,
-				struct page **pagep, void **fsdata);
-
-int pagecache_write_end(struct file *, struct address_space *mapping,
-				loff_t pos, unsigned len, unsigned copied,
-				struct page *page, void *fsdata);
-
 /**
  * struct address_space - Contents of a cacheable, mappable object.
  * @host: Owner, either the inode or the block_device.
@@ -3116,8 +3100,6 @@ extern int page_readlink(struct dentry *, char __user *, int);
 extern const char *page_get_link(struct dentry *, struct inode *,
 				 struct delayed_call *);
 extern void page_put_link(void *);
-extern int __page_symlink(struct inode *inode, const char *symname, int len,
-		int nofs);
 extern int page_symlink(struct inode *inode, const char *symname, int len);
 extern const struct inode_operations page_symlink_inode_operations;
 extern void kfree_link(void *);
@@ -3192,7 +3174,7 @@ extern int noop_fsync(struct file *, loff_t, loff_t, int);
 extern ssize_t noop_direct_IO(struct kiocb *iocb, struct iov_iter *iter);
 extern int simple_empty(struct dentry *);
 extern int simple_write_begin(struct file *file, struct address_space *mapping,
-			loff_t pos, unsigned len, unsigned flags,
+			loff_t pos, unsigned len,
 			struct page **pagep, void **fsdata);
 extern const struct address_space_operations ram_aops;
 extern int always_delete_dentry(const struct dentry *);
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index 5b6f64f4d771..e552097c67e0 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -226,10 +226,10 @@ static inline const struct iomap *iomap_iter_srcmap(const struct iomap_iter *i)
 
 ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
 		const struct iomap_ops *ops);
-int iomap_readpage(struct page *page, const struct iomap_ops *ops);
+int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops);
 void iomap_readahead(struct readahead_control *, const struct iomap_ops *ops);
 bool iomap_is_partially_uptodate(struct folio *, size_t from, size_t count);
-int iomap_releasepage(struct page *page, gfp_t gfp_mask);
+bool iomap_release_folio(struct folio *folio, gfp_t gfp_flags);
 void iomap_invalidate_folio(struct folio *folio, size_t offset, size_t len);
 #ifdef CONFIG_MIGRATION
 int iomap_migrate_page(struct address_space *mapping, struct page *newpage,
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index de9536680b2b..e79d6e0b14e8 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -1529,7 +1529,7 @@ extern int	 jbd2_journal_dirty_metadata (handle_t *, struct buffer_head *);
 extern int	 jbd2_journal_forget (handle_t *, struct buffer_head *);
 int jbd2_journal_invalidate_folio(journal_t *, struct folio *,
 					size_t offset, size_t length);
-extern int	 jbd2_journal_try_to_free_buffers(journal_t *journal, struct page *page);
+bool jbd2_journal_try_to_free_buffers(journal_t *journal, struct folio *folio);
 extern int	 jbd2_journal_stop(handle_t *);
 extern int	 jbd2_journal_flush(journal_t *journal, unsigned int flags);
 extern void	 jbd2_journal_lock_updates (journal_t *);
diff --git a/include/linux/mpage.h b/include/linux/mpage.h
index f4f5e90a6844..43986f7ec4dd 100644
--- a/include/linux/mpage.h
+++ b/include/linux/mpage.h
@@ -16,7 +16,7 @@ struct writeback_control;
 struct readahead_control;
 
 void mpage_readahead(struct readahead_control *, get_block_t get_block);
-int mpage_readpage(struct page *page, get_block_t get_block);
+int mpage_read_folio(struct folio *folio, get_block_t get_block);
 int mpage_writepages(struct address_space *mapping,
 		struct writeback_control *wbc, get_block_t get_block);
 int mpage_writepage(struct page *page, get_block_t *get_block,
diff --git a/include/linux/netfs.h b/include/linux/netfs.h
index 80b7728277b1..77fa6a61706a 100644
--- a/include/linux/netfs.h
+++ b/include/linux/netfs.h
@@ -275,9 +275,9 @@ struct netfs_cache_ops {
 
 struct readahead_control;
 extern void netfs_readahead(struct readahead_control *);
-extern int netfs_readpage(struct file *, struct page *);
+int netfs_read_folio(struct file *, struct folio *);
 extern int netfs_write_begin(struct file *, struct address_space *,
-			     loff_t, unsigned int, unsigned int, struct folio **,
+			     loff_t, unsigned int, struct folio **,
 			     void **);
 
 extern void netfs_subreq_terminated(struct netfs_io_subrequest *, ssize_t, bool);
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index b48b9259e02c..1bba71757d62 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -594,7 +594,7 @@ static inline bool nfs_have_writebacks(const struct inode *inode)
 /*
  * linux/fs/nfs/read.c
  */
-extern int  nfs_readpage(struct file *, struct page *);
+int  nfs_read_folio(struct file *, struct folio *);
 void nfs_readahead(struct readahead_control *);
 
 /*
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 9d8eeaa67d05..af10149a6c31 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -516,7 +516,7 @@ PAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
 /*
  * Private page markings that may be used by the filesystem that owns the page
  * for its own purposes.
- * - PG_private and PG_private_2 cause releasepage() and co to be invoked
+ * - PG_private and PG_private_2 cause release_folio() and co to be invoked
  */
 PAGEFLAG(Private, private, PF_ANY)
 PAGEFLAG(Private2, private_2, PF_ANY) TESTSCFLAG(Private2, private_2, PF_ANY)
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 6165283bdb6f..ce96866fbec4 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -492,7 +492,7 @@ static inline gfp_t readahead_gfp_mask(struct address_space *x)
 	return mapping_gfp_mask(x) | __GFP_NORETRY | __GFP_NOWARN;
 }
 
-typedef int filler_t(void *, struct page *);
+typedef int filler_t(struct file *, struct folio *);
 
 pgoff_t page_cache_next_miss(struct address_space *mapping,
 			     pgoff_t index, unsigned long max_scan);
@@ -735,7 +735,7 @@ static inline unsigned find_get_pages_tag(struct address_space *mapping,
 }
 
 struct page *grab_cache_page_write_begin(struct address_space *mapping,
-			pgoff_t index, unsigned flags);
+			pgoff_t index);
 
 /*
  * Returns locked page at given index in given cache, creating it if needed.
@@ -747,9 +747,9 @@ static inline struct page *grab_cache_page(struct address_space *mapping,
 }
 
 struct folio *read_cache_folio(struct address_space *, pgoff_t index,
-		filler_t *filler, void *data);
+		filler_t *filler, struct file *file);
 struct page *read_cache_page(struct address_space *, pgoff_t index,
-		filler_t *filler, void *data);
+		filler_t *filler, struct file *file);
 extern struct page * read_cache_page_gfp(struct address_space *mapping,
 				pgoff_t index, gfp_t gfp_mask);
 
@@ -888,6 +888,18 @@ bool __folio_lock_or_retry(struct folio *folio, struct mm_struct *mm,
 void unlock_page(struct page *page);
 void folio_unlock(struct folio *folio);
 
+/**
+ * folio_trylock() - Attempt to lock a folio.
+ * @folio: The folio to attempt to lock.
+ *
+ * Sometimes it is undesirable to wait for a folio to be unlocked (eg
+ * when the locks are being taken in the wrong order, or if making
+ * progress through a batch of folios is more important than processing
+ * them in order).  Usually folio_lock() is the correct function to call.
+ *
+ * Context: Any context.
+ * Return: Whether the lock was successfully acquired.
+ */
 static inline bool folio_trylock(struct folio *folio)
 {
 	return likely(!test_and_set_bit_lock(PG_locked, folio_flags(folio, 0)));
@@ -901,6 +913,28 @@ static inline int trylock_page(struct page *page)
 	return folio_trylock(page_folio(page));
 }
 
+/**
+ * folio_lock() - Lock this folio.
+ * @folio: The folio to lock.
+ *
+ * The folio lock protects against many things, probably more than it
+ * should.  It is primarily held while a folio is being brought uptodate,
+ * either from its backing file or from swap.  It is also held while a
+ * folio is being truncated from its address_space, so holding the lock
+ * is sufficient to keep folio->mapping stable.
+ *
+ * The folio lock is also held while write() is modifying the page to
+ * provide POSIX atomicity guarantees (as long as the write does not
+ * cross a page boundary).  Other modifications to the data in the folio
+ * do not hold the folio lock and can race with writes, eg DMA and stores
+ * to mapped pages.
+ *
+ * Context: May sleep.  If you need to acquire the locks of two or
+ * more folios, they must be in order of ascending index, if they are
+ * in the same address_space.  If they are in different address_spaces,
+ * acquire the lock of the folio which belongs to the address_space which
+ * has the lowest address in memory first.
+ */
 static inline void folio_lock(struct folio *folio)
 {
 	might_sleep();
@@ -908,8 +942,16 @@ static inline void folio_lock(struct folio *folio)
 		__folio_lock(folio);
 }
 
-/*
- * lock_page may only be called if we have the page's inode pinned.
+/**
+ * lock_page() - Lock the folio containing this page.
+ * @page: The page to lock.
+ *
+ * See folio_lock() for a description of what the lock protects.
+ * This is a legacy function and new code should probably use folio_lock()
+ * instead.
+ *
+ * Context: May sleep.  Pages in the same folio share a lock, so do not
+ * attempt to lock two pages which share a folio.
  */
 static inline void lock_page(struct page *page)
 {
@@ -921,6 +963,16 @@ static inline void lock_page(struct page *page)
 		__folio_lock(folio);
 }
 
+/**
+ * folio_lock_killable() - Lock this folio, interruptible by a fatal signal.
+ * @folio: The folio to lock.
+ *
+ * Attempts to lock the folio, like folio_lock(), except that the sleep
+ * to acquire the lock is interruptible by a fatal signal.
+ *
+ * Context: May sleep; see folio_lock().
+ * Return: 0 if the lock was acquired; -EINTR if a fatal signal was received.
+ */
 static inline int folio_lock_killable(struct folio *folio)
 {
 	might_sleep();
@@ -967,8 +1019,8 @@ int folio_wait_bit_killable(struct folio *folio, int bit_nr);
  * Wait for a folio to be unlocked.
  *
  * This must be called with the caller "holding" the folio,
- * ie with increased "page->count" so that the folio won't
- * go away during the wait..
+ * ie with increased folio reference count so that the folio won't
+ * go away during the wait.
  */
 static inline void folio_wait_locked(struct folio *folio)
 {
@@ -1015,10 +1067,6 @@ static inline void folio_cancel_dirty(struct folio *folio)
 	if (folio_test_dirty(folio))
 		__folio_cancel_dirty(folio);
 }
-static inline void cancel_dirty_page(struct page *page)
-{
-	folio_cancel_dirty(page_folio(page));
-}
 bool folio_clear_dirty_for_io(struct folio *folio);
 bool clear_page_dirty_for_io(struct page *page);
 void folio_invalidate(struct folio *folio, size_t offset, size_t length);
@@ -1191,7 +1239,7 @@ void page_cache_sync_readahead(struct address_space *mapping,
  * @mapping: address_space which holds the pagecache and I/O vectors
  * @ra: file_ra_state which holds the readahead state
  * @file: Used by the filesystem for authentication.
- * @page: The page at @index which triggered the readahead call.
+ * @folio: The folio at @index which triggered the readahead call.
  * @index: Index of first page to be read.
  * @req_count: Total number of pages being read by the caller.
  *
@@ -1203,10 +1251,10 @@ void page_cache_sync_readahead(struct address_space *mapping,
 static inline
 void page_cache_async_readahead(struct address_space *mapping,
 		struct file_ra_state *ra, struct file *file,
-		struct page *page, pgoff_t index, unsigned long req_count)
+		struct folio *folio, pgoff_t index, unsigned long req_count)
 {
 	DEFINE_READAHEAD(ractl, file, ra, mapping, index);
-	page_cache_async_ra(&ractl, page_folio(page), req_count);
+	page_cache_async_ra(&ractl, folio, req_count);
 }
 
 static inline struct folio *__readahead_folio(struct readahead_control *ractl)