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
  ...

Author: torvalds

Documentation/filesystems/caching/netfs-api.rst

@@ -433,11 +433,11 @@ has done a write and then the page it wrote from has been released by the VM,
 after which it *has* to look in the cache.
 
 To inform fscache that a page might now be in the cache, the following function
-should be called from the ``releasepage`` address space op::
+should be called from the ``release_folio`` address space op::
 
 	void fscache_note_page_release(struct fscache_cookie *cookie);
 
-if the page has been released (ie. releasepage returned true).
+if the page has been released (ie. release_folio returned true).
 
 Page release and page invalidation should also wait for any mark left on the
 page to say that a DIO write is underway from that page::

Documentation/filesystems/fscrypt.rst

@@ -1256,7 +1256,7 @@ inline encryption hardware will encrypt/decrypt the file contents.
 When inline encryption isn't used, filesystems must encrypt/decrypt
 the file contents themselves, as described below:
 
-For the read path (->readpage()) of regular files, filesystems can
+For the read path (->read_folio()) of regular files, filesystems can
 read the ciphertext into the page cache and decrypt it in-place.  The
 page lock must be held until decryption has finished, to prevent the
 page from becoming visible to userspace prematurely.

Documentation/filesystems/fsverity.rst

@@ -559,7 +559,7 @@ already verified).  Below, we describe how filesystems implement this.
 Pagecache
 ~~~~~~~~~
 
-For filesystems using Linux's pagecache, the ``->readpage()`` and
+For filesystems using Linux's pagecache, the ``->read_folio()`` and
 ``->readahead()`` methods must be modified to verify pages before they
 are marked Uptodate.  Merely hooking ``->read_iter()`` would be
 insufficient, since ``->read_iter()`` is not used for memory maps.

Documentation/filesystems/locking.rst

@@ -237,20 +237,20 @@ address_space_operations
 prototypes::
 
 	int (*writepage)(struct page *page, struct writeback_control *wbc);
-	int (*readpage)(struct file *, struct page *);
+	int (*read_folio)(struct file *, struct folio *);
 	int (*writepages)(struct address_space *, struct writeback_control *);
 	bool (*dirty_folio)(struct address_space *, struct folio *folio);
 	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,
 				struct page *page, void *fsdata);
 	sector_t (*bmap)(struct address_space *, sector_t);
 	void (*invalidate_folio) (struct folio *, size_t start, size_t len);
-	int (*releasepage) (struct page *, int);
-	void (*freepage)(struct page *);
+	bool (*release_folio)(struct folio *, gfp_t);
+	void (*free_folio)(struct folio *);
 	int (*direct_IO)(struct kiocb *, struct iov_iter *iter);
 	bool (*isolate_page) (struct page *, isolate_mode_t);
 	int (*migratepage)(struct address_space *, struct page *, struct page *);
@@ -262,22 +262,22 @@ prototypes::
 	int (*swap_deactivate)(struct file *);
 
 locking rules:
-	All except dirty_folio and freepage may block
+	All except dirty_folio and free_folio may block
 
 ======================	======================== =========	===============
-ops			PageLocked(page)	 i_rwsem	invalidate_lock
+ops			folio locked		 i_rwsem	invalidate_lock
 ======================	======================== =========	===============
 writepage:		yes, unlocks (see below)
-readpage:		yes, unlocks				shared
+read_folio:		yes, unlocks				shared
 writepages:
-dirty_folio		maybe
+dirty_folio:		maybe
 readahead:		yes, unlocks				shared
 write_begin:		locks the page		 exclusive
 write_end:		yes, unlocks		 exclusive
 bmap:
 invalidate_folio:	yes					exclusive
-releasepage:		yes
-freepage:		yes
+release_folio:		yes
+free_folio:		yes
 direct_IO:
 isolate_page:		yes
 migratepage:		yes (both)
@@ -289,13 +289,13 @@ swap_activate:		no
 swap_deactivate:	no
 ======================	======================== =========	===============
 
-->write_begin(), ->write_end() and ->readpage() may be called from
+->write_begin(), ->write_end() and ->read_folio() may be called from
 the request handler (/dev/loop).
 
-->readpage() unlocks the page, either synchronously or via I/O
+->read_folio() unlocks the folio, either synchronously or via I/O
 completion.
 
-->readahead() unlocks the pages that I/O is attempted on like ->readpage().
+->readahead() unlocks the folios that I/O is attempted on like ->read_folio().
 
 ->writepage() is used for two purposes: for "memory cleansing" and for
 "sync".  These are quite different operations and the behaviour may differ
@@ -372,12 +372,12 @@ invalidate_lock before invalidating page cache in truncate / hole punch
 path (and thus calling into ->invalidate_folio) to block races between page
 cache invalidation and page cache filling functions (fault, read, ...).
 
-->releasepage() is called when the kernel is about to try to drop the
-buffers from the page in preparation for freeing it.  It returns zero to
-indicate that the buffers are (or may be) freeable.  If ->releasepage is zero,
-the kernel assumes that the fs has no private interest in the buffers.
+->release_folio() is called when the kernel is about to try to drop the
+buffers from the folio in preparation for freeing it.  It returns false to
+indicate that the buffers are (or may be) freeable.  If ->release_folio is
+NULL, the kernel assumes that the fs has no private interest in the buffers.
 
-->freepage() is called when the kernel is done dropping the page
+->free_folio() is called when the kernel has dropped the folio
 from the page cache.
 
 ->launder_folio() may be called prior to releasing a folio if

Documentation/filesystems/netfs_library.rst

@@ -96,7 +96,7 @@ attached to an inode (or NULL if fscache is disabled)::
 Buffered Read Helpers
 =====================
 
-The library provides a set of read helpers that handle the ->readpage(),
+The library provides a set of read helpers that handle the ->read_folio(),
 ->readahead() and much of the ->write_begin() VM operations and translate them
 into a common call framework.
 
@@ -136,20 +136,19 @@ Read Helper Functions
 Three read helpers are provided::
 
 	void netfs_readahead(struct readahead_control *ractl);
-	int netfs_readpage(struct file *file,
-			   struct page *page);
+	int netfs_read_folio(struct file *file,
+			   struct folio *folio);
 	int netfs_write_begin(struct file *file,
 			      struct address_space *mapping,
 			      loff_t pos,
 			      unsigned int len,
-			      unsigned int flags,
 			      struct folio **_folio,
 			      void **_fsdata);
 
 Each corresponds to a VM address space operation.  These operations use the
 state in the per-inode context.
 
-For ->readahead() and ->readpage(), the network filesystem just point directly
+For ->readahead() and ->read_folio(), the network filesystem just point directly
 at the corresponding read helper; whereas for ->write_begin(), it may be a
 little more complicated as the network filesystem might want to flush
 conflicting writes or track dirty data and needs to put the acquired folio if

Documentation/filesystems/porting.rst

@@ -624,7 +624,7 @@ any symlink that might use page_follow_link_light/page_put_link() must
 have inode_nohighmem(inode) called before anything might start playing with
 its pagecache.  No highmem pages should end up in the pagecache of such
 symlinks.  That includes any preseeding that might be done during symlink
-creation.  __page_symlink() will honour the mapping gfp flags, so once
+creation.  page_symlink() will honour the mapping gfp flags, so once
 you've done inode_nohighmem() it's safe to use, but if you allocate and
 insert the page manually, make sure to use the right gfp flags.
 

Documentation/filesystems/vfs.rst

@@ -620,9 +620,9 @@ Writeback.
 The first can be used independently to the others.  The VM can try to
 either write dirty pages in order to clean them, or release clean pages
 in order to reuse them.  To do this it can call the ->writepage method
-on dirty pages, and ->releasepage on clean pages with PagePrivate set.
-Clean pages without PagePrivate and with no external references will be
-released without notice being given to the address_space.
+on dirty pages, and ->release_folio on clean folios with the private
+flag set.  Clean pages without PagePrivate and with no external references
+will be released without notice being given to the address_space.
 
 To achieve this functionality, pages need to be placed on an LRU with
 lru_cache_add and mark_page_active needs to be called whenever the page
@@ -656,7 +656,7 @@ by memory-mapping the page.  Data is written into the address space by
 the application, and then written-back to storage typically in whole
 pages, however the address_space has finer control of write sizes.
 
-The read process essentially only requires 'readpage'.  The write
+The read process essentially only requires 'read_folio'.  The write
 process is more complicated and uses write_begin/write_end or
 dirty_folio to write data into the address_space, and writepage and
 writepages to writeback data to storage.
@@ -722,20 +722,20 @@ cache in your filesystem.  The following members are defined:
 
 	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 *);
 		int (*writepages)(struct address_space *, struct writeback_control *);
 		bool (*dirty_folio)(struct address_space *, struct folio *);
 		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,
 				 struct page *page, void *fsdata);
 		sector_t (*bmap)(struct address_space *, sector_t);
 		void (*invalidate_folio) (struct folio *, size_t start, size_t len);
-		int (*releasepage) (struct page *, int);
-		void (*freepage)(struct page *);
+		bool (*release_folio)(struct folio *, gfp_t);
+		void (*free_folio)(struct folio *);
 		ssize_t (*direct_IO)(struct kiocb *, struct iov_iter *iter);
 		/* isolate a page for migration */
 		bool (*isolate_page) (struct page *, isolate_mode_t);
@@ -747,7 +747,7 @@ cache in your filesystem.  The following members are defined:
 
 		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 *, bool *);
 		int (*error_remove_page) (struct mapping *mapping, struct page *page);
 		int (*swap_activate)(struct file *);
 		int (*swap_deactivate)(struct file *);
@@ -772,14 +772,14 @@ cache in your filesystem.  The following members are defined:
 
 	See the file "Locking" for more details.
 
-``readpage``
-	called by the VM to read a page from backing store.  The page
-	will be Locked when readpage is called, and should be unlocked
-	and marked uptodate once the read completes.  If ->readpage
-	discovers that it needs to unlock the page for some reason, it
-	can do so, and then return AOP_TRUNCATED_PAGE.  In this case,
-	the page will be relocated, relocked and if that all succeeds,
-	->readpage will be called again.
+``read_folio``
+	called by the VM to read a folio from backing store.  The folio
+	will be locked when read_folio is called, and should be unlocked
+	and marked uptodate once the read completes.  If ->read_folio
+	discovers that it cannot perform the I/O at this time, it can
+        unlock the folio and return AOP_TRUNCATED_PAGE.  In this case,
+	the folio will be looked up again, relocked and if that all succeeds,
+	->read_folio will be called again.
 
 ``writepages``
 	called by the VM to write out pages associated with the
@@ -832,9 +832,6 @@ cache in your filesystem.  The following members are defined:
 	passed to write_begin is greater than the number of bytes copied
 	into the page).
 
-	flags is a field for AOP_FLAG_xxx flags, described in
-	include/linux/fs.h.
-
 	A void * may be returned in fsdata, which then gets passed into
 	write_end.
 
@@ -867,36 +864,35 @@ cache in your filesystem.  The following members are defined:
 	address space.  This generally corresponds to either a
 	truncation, punch hole or a complete invalidation of the address
 	space (in the latter case 'offset' will always be 0 and 'length'
-	will be folio_size()).  Any private data associated with the page
+	will be folio_size()).  Any private data associated with the folio
 	should be updated to reflect this truncation.  If offset is 0
 	and length is folio_size(), then the private data should be
-	released, because the page must be able to be completely
-	discarded.  This may be done by calling the ->releasepage
+	released, because the folio must be able to be completely
+	discarded.  This may be done by calling the ->release_folio
 	function, but in this case the release MUST succeed.
 
-``releasepage``
-	releasepage is called on PagePrivate pages to indicate that the
-	page should be freed if possible.  ->releasepage should remove
-	any private data from the page and clear the PagePrivate flag.
-	If releasepage() fails for some reason, it must indicate failure
-	with a 0 return value.  releasepage() is used in two distinct
-	though related cases.  The first is when the VM finds a clean
-	page with no active users and wants to make it a free page.  If
-	->releasepage succeeds, the page will be removed from the
-	address_space and become free.
+``release_folio``
+	release_folio is called on folios with private data to tell the
+	filesystem that the folio is about to be freed.  ->release_folio
+	should remove any private data from the folio and clear the
+	private flag.  If release_folio() fails, it should return false.
+	release_folio() is used in two distinct though related cases.
+	The first is when the VM wants to free a clean folio with no
+	active users.  If ->release_folio succeeds, the folio will be
+	removed from the address_space and be freed.
 
 	The second case is when a request has been made to invalidate
-	some or all pages in an address_space.  This can happen through
-	the fadvise(POSIX_FADV_DONTNEED) system call or by the
-	filesystem explicitly requesting it as nfs and 9fs do (when they
+	some or all folios in an address_space.  This can happen
+	through the fadvise(POSIX_FADV_DONTNEED) system call or by the
+	filesystem explicitly requesting it as nfs and 9p do (when they
 	believe the cache may be out of date with storage) by calling
 	invalidate_inode_pages2().  If the filesystem makes such a call,
-	and needs to be certain that all pages are invalidated, then its
-	releasepage will need to ensure this.  Possibly it can clear the
-	PageUptodate bit if it cannot free private data yet.
+	and needs to be certain that all folios are invalidated, then
+	its release_folio will need to ensure this.  Possibly it can
+	clear the uptodate flag if it cannot free private data yet.
 
-``freepage``
-	freepage is called once the page is no longer visible in the
+``free_folio``
+	free_folio is called once the folio is no longer visible in the
 	page cache in order to allow the cleanup of any private data.
 	Since it may be called by the memory reclaimer, it should not
 	assume that the original address_space mapping still exists, and
@@ -935,14 +931,14 @@ cache in your filesystem.  The following members are defined:
 	without needing I/O to bring the whole page up to date.
 
 ``is_dirty_writeback``
-	Called by the VM when attempting to reclaim a page.  The VM uses
+	Called by the VM when attempting to reclaim a folio.  The VM uses
 	dirty and writeback information to determine if it needs to
 	stall to allow flushers a chance to complete some IO.
-	Ordinarily it can use PageDirty and PageWriteback but some
-	filesystems have more complex state (unstable pages in NFS
+	Ordinarily it can use folio_test_dirty and folio_test_writeback but
+	some filesystems have more complex state (unstable folios in NFS
 	prevent reclaim) or do not set those flags due to locking
 	problems.  This callback allows a filesystem to indicate to the
-	VM if a page should be treated as dirty or writeback for the
+	VM if a folio should be treated as dirty or writeback for the
 	purposes of stalling.
 
 ``error_remove_page``

MAINTAINERS

@@ -14878,6 +14878,19 @@ F:	Documentation/core-api/padata.rst
 F:	include/linux/padata.h
 F:	kernel/padata.c
 
+PAGE CACHE
+M:	Matthew Wilcox (Oracle) <willy@infradead.org>
+L:	linux-fsdevel@vger.kernel.org
+S:	Supported
+T:	git git://git.infradead.org/users/willy/pagecache.git
+F:	Documentation/filesystems/locking.rst
+F:	Documentation/filesystems/vfs.rst
+F:	include/linux/pagemap.h
+F:	mm/filemap.c
+F:	mm/page-writeback.c
+F:	mm/readahead.c
+F:	mm/truncate.c
+
 PAGE POOL
 M:	Jesper Dangaard Brouer <hawk@kernel.org>
 M:	Ilias Apalodimas <ilias.apalodimas@linaro.org>

block/fops.c

@@ -372,9 +372,9 @@ static int blkdev_writepage(struct page *page, struct writeback_control *wbc)
 	return block_write_full_page(page, blkdev_get_block, wbc);
 }
 
-static int blkdev_readpage(struct file * file, struct page * page)
+static int blkdev_read_folio(struct file *file, struct folio *folio)
 {
-	return block_read_full_page(page, blkdev_get_block);
+	return block_read_full_folio(folio, blkdev_get_block);
 }
 
 static void blkdev_readahead(struct readahead_control *rac)
@@ -383,11 +383,9 @@ static void blkdev_readahead(struct readahead_control *rac)
 }
 
 static int blkdev_write_begin(struct file *file, struct address_space *mapping,
-		loff_t pos, unsigned len, unsigned flags, struct page **pagep,
-		void **fsdata)
+		loff_t pos, unsigned len, struct page **pagep, void **fsdata)
 {
-	return block_write_begin(mapping, pos, len, flags, pagep,
-				 blkdev_get_block);
+	return block_write_begin(mapping, pos, len, pagep, blkdev_get_block);
 }
 
 static int blkdev_write_end(struct file *file, struct address_space *mapping,
@@ -412,7 +410,7 @@ static int blkdev_writepages(struct address_space *mapping,
 const struct address_space_operations def_blk_aops = {
 	.dirty_folio	= block_dirty_folio,
 	.invalidate_folio = block_invalidate_folio,
-	.readpage	= blkdev_readpage,
+	.read_folio	= blkdev_read_folio,
 	.readahead	= blkdev_readahead,
 	.writepage	= blkdev_writepage,
 	.write_begin	= blkdev_write_begin,