[PATCH v3 0/6] netfs, 9p, afs, ceph: Support folios, at least partially

[PATCH v3 0/6] netfs, 9p, afs, ceph: Support folios, at least partially

[David Howells]

Here's a set of patches to convert netfs, 9p and afs to use folios and to
provide sufficient conversion for ceph that it can continue to use the
netfs library.  Jeff Layton is working on fully converting ceph.

This also contains a patch to split afs symlink readpage from afs file
readpage to aid with foliation and a patch to convert 9p to netfslib to
reduce the amount of foliation needed there.

Changes
=======
ver #3:
 - Rebased on upstream as folios have been pulled.
 - Imported a patch to convert 9p to netfslib from my
   fscache-remove-old-api branch[3].
 - Foliated netfslib.

ver #2:
 - Reorder the patches to put both non-folio afs patches to the front.
 - Use page_offset() rather than manual calculation[1].
 - Fix folio_inode() to directly access the inode[2].

David

Link: https://lore.kernel.org/r/YST/0e92OdSH0zjg@casper.infradead.org/ [1]
Link: https://lore.kernel.org/r/YST8OcVNy02Rivbm@casper.infradead.org/ [2]
Link: https://lore.kernel.org/r/163551653404.1877519.12363794970541005441.stgit@warthog.procyon.org.uk/ [3]
Link: https://lore.kernel.org/r/2408234.1628687271@warthog.procyon.org.uk/ # v0
Link: https://lore.kernel.org/r/162981147473.1901565.1455657509200944265.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163005740700.2472992.12365214290752300378.stgit@warthog.procyon.org.uk/ # v2
---
David Howells (6):
      afs: Sort out symlink reading
      9p: Convert to using the netfs helper lib to do reads and caching
      folio: Add a function to change the private data attached to a folio
      folio: Add a function to get the host inode for a folio
      netfs, 9p, afs, ceph: Use folios
      afs: Use folios in directory handling


 fs/9p/Kconfig              |   1 +
 fs/9p/cache.c              | 137 ---------------
 fs/9p/cache.h              |  97 +----------
 fs/9p/v9fs.h               |   9 +
 fs/9p/vfs_addr.c           | 253 +++++++++++++--------------
 fs/9p/vfs_file.c           |  29 ++--
 fs/afs/dir.c               | 229 ++++++++++--------------
 fs/afs/dir_edit.c          | 154 +++++++++--------
 fs/afs/file.c              |  70 ++++----
 fs/afs/internal.h          |  46 ++---
 fs/afs/write.c             | 346 ++++++++++++++++++-------------------
 fs/ceph/addr.c             |  80 +++++----
 fs/netfs/read_helper.c     | 165 +++++++++---------
 include/linux/netfs.h      |  12 +-
 include/linux/pagemap.h    |  33 ++++
 include/trace/events/afs.h |  21 +--
 mm/page-writeback.c        |   2 +-
 17 files changed, 738 insertions(+), 946 deletions(-)

[PATCH v3 1/6] afs: Sort out symlink reading

[David Howells]

afs_readpage() doesn't get a file pointer when called for a symlink, so
separate it from regular file pointer handling.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Link: https://lore.kernel.org/r/162687508008.276387.6418924257569297305.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/162981152280.1901565.2264055504466731917.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/163005742570.2472992.7800423440314043178.stgit@warthog.procyon.org.uk/ # v2
---

 fs/afs/file.c     |   14 +++++++++-----
 fs/afs/inode.c    |    6 +++---
 fs/afs/internal.h |    3 ++-
 3 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/fs/afs/file.c b/fs/afs/file.c
index e6c447ae91f3..eb11d047c0ae 100644
--- a/fs/afs/file.c
+++ b/fs/afs/file.c
@@ -19,6 +19,7 @@
 
 static int afs_file_mmap(struct file *file, struct vm_area_struct *vma);
 static int afs_readpage(struct file *file, struct page *page);
+static int afs_symlink_readpage(struct file *file, struct page *page);
 static void afs_invalidatepage(struct page *page, unsigned int offset,
 			       unsigned int length);
 static int afs_releasepage(struct page *page, gfp_t gfp_flags);
@@ -49,7 +50,7 @@ const struct inode_operations afs_file_inode_operations = {
 	.permission	= afs_permission,
 };
 
-const struct address_space_operations afs_fs_aops = {
+const struct address_space_operations afs_file_aops = {
 	.readpage	= afs_readpage,
 	.readahead	= afs_readahead,
 	.set_page_dirty	= afs_set_page_dirty,
@@ -62,6 +63,12 @@ const struct address_space_operations afs_fs_aops = {
 	.writepages	= afs_writepages,
 };
 
+const struct address_space_operations afs_symlink_aops = {
+	.readpage	= afs_symlink_readpage,
+	.releasepage	= afs_releasepage,
+	.invalidatepage	= afs_invalidatepage,
+};
+
 static const struct vm_operations_struct afs_vm_ops = {
 	.open		= afs_vm_open,
 	.close		= afs_vm_close,
@@ -313,7 +320,7 @@ static void afs_req_issue_op(struct netfs_read_subrequest *subreq)
 	afs_put_read(fsreq);
 }
 
-static int afs_symlink_readpage(struct page *page)
+static int afs_symlink_readpage(struct file *file, struct page *page)
 {
 	struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
 	struct afs_read *fsreq;
@@ -378,9 +385,6 @@ const struct netfs_read_request_ops afs_req_ops = {
 
 static int afs_readpage(struct file *file, struct page *page)
 {
-	if (!file)
-		return afs_symlink_readpage(page);
-
 	return netfs_readpage(file, page, &afs_req_ops, NULL);
 }
 
diff --git a/fs/afs/inode.c b/fs/afs/inode.c
index 8fcffea2daf5..16906eb592d9 100644
--- a/fs/afs/inode.c
+++ b/fs/afs/inode.c
@@ -95,7 +95,7 @@ static int afs_inode_init_from_status(struct afs_operation *op,
 		inode->i_mode	= S_IFREG | (status->mode & S_IALLUGO);
 		inode->i_op	= &afs_file_inode_operations;
 		inode->i_fop	= &afs_file_operations;
-		inode->i_mapping->a_ops	= &afs_fs_aops;
+		inode->i_mapping->a_ops	= &afs_file_aops;
 		break;
 	case AFS_FTYPE_DIR:
 		inode->i_mode	= S_IFDIR |  (status->mode & S_IALLUGO);
@@ -113,11 +113,11 @@ static int afs_inode_init_from_status(struct afs_operation *op,
 			inode->i_mode	= S_IFDIR | 0555;
 			inode->i_op	= &afs_mntpt_inode_operations;
 			inode->i_fop	= &afs_mntpt_file_operations;
-			inode->i_mapping->a_ops	= &afs_fs_aops;
+			inode->i_mapping->a_ops	= &afs_symlink_aops;
 		} else {
 			inode->i_mode	= S_IFLNK | status->mode;
 			inode->i_op	= &afs_symlink_inode_operations;
-			inode->i_mapping->a_ops	= &afs_fs_aops;
+			inode->i_mapping->a_ops	= &afs_symlink_aops;
 		}
 		inode_nohighmem(inode);
 		break;
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index 0ad97a8fc0d4..9357c53faa69 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -1055,7 +1055,8 @@ extern void afs_dynroot_depopulate(struct super_block *);
 /*
  * file.c
  */
-extern const struct address_space_operations afs_fs_aops;
+extern const struct address_space_operations afs_file_aops;
+extern const struct address_space_operations afs_symlink_aops;
 extern const struct inode_operations afs_file_inode_operations;
 extern const struct file_operations afs_file_operations;
 extern const struct netfs_read_request_ops afs_req_ops;

[PATCH v3 2/6] 9p: Convert to using the netfs helper lib to do reads and caching

[David Howells]

Convert the 9p filesystem to use the netfs helper lib to handle readpage,
readahead and write_begin, converting those into a common issue_op for the
filesystem itself to handle.  The netfs helper lib also handles reading
from fscache if a cache is available, and interleaving reads from both
sources.

This change also switches from the old fscache I/O API to the new one,
meaning that fscache no longer keeps track of netfs pages and instead does
async DIO between the backing files and the 9p file pagecache.  As a part
of this change, the handling of PG_fscache changes.  It now just means that
the cache has a write I/O operation in progress on a page (PG_locked
is used for a read I/O op).

Note that this is a cut-down version of the fscache rewrite and does not
change any of the cookie and cache coherency handling.

Changes
=======
ver #4:
  - Rebase on top of folios.
  - Don't use wait_on_page_bit_killable().

ver #3:
  - v9fs_req_issue_op() needs to terminate the subrequest.
  - v9fs_write_end() needs to call SetPageUptodate() a bit more often.
  - It's not CONFIG_{AFS,V9FS}_FSCACHE[1]
  - v9fs_init_rreq() should take a ref on the p9_fid and the cleanup should
    drop it [from Dominique Martinet].

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-and-tested-by: Dominique Martinet <asmadeus@codewreck.org>
cc: v9fs-developer@lists.sourceforge.net
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/YUm+xucHxED+1MJp@codewreck.org/ [1]
Link: https://lore.kernel.org/r/163162772646.438332.16323773205855053535.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/163189109885.2509237.7153668924503399173.stgit@warthog.procyon.org.uk/ # rfc v2
Link: https://lore.kernel.org/r/163363943896.1980952.1226527304649419689.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/163551662876.1877519.14706391695553204156.stgit@warthog.procyon.org.uk/ # v4
---

 fs/9p/Kconfig    |    1 
 fs/9p/cache.c    |  137 --------------------------------------
 fs/9p/cache.h    |   97 +--------------------------
 fs/9p/v9fs.h     |    9 ++
 fs/9p/vfs_addr.c |  195 +++++++++++++++++++++++++++---------------------------
 fs/9p/vfs_file.c |   17 ++++-
 6 files changed, 122 insertions(+), 334 deletions(-)

diff --git a/fs/9p/Kconfig b/fs/9p/Kconfig
index 09fd4a185fd2..d7bc93447c85 100644
--- a/fs/9p/Kconfig
+++ b/fs/9p/Kconfig
@@ -2,6 +2,7 @@
 config 9P_FS
 	tristate "Plan 9 Resource Sharing Support (9P2000)"
 	depends on INET && NET_9P
+	select NETFS_SUPPORT
 	help
 	  If you say Y here, you will get experimental support for
 	  Plan 9 resource sharing via the 9P2000 protocol.
diff --git a/fs/9p/cache.c b/fs/9p/cache.c
index 1769a44f4819..077f0a40aa01 100644
--- a/fs/9p/cache.c
+++ b/fs/9p/cache.c
@@ -199,140 +199,3 @@ void v9fs_cache_inode_reset_cookie(struct inode *inode)
 
 	mutex_unlock(&v9inode->fscache_lock);
 }
-
-int __v9fs_fscache_release_page(struct page *page, gfp_t gfp)
-{
-	struct inode *inode = page->mapping->host;
-	struct v9fs_inode *v9inode = V9FS_I(inode);
-
-	BUG_ON(!v9inode->fscache);
-
-	return fscache_maybe_release_page(v9inode->fscache, page, gfp);
-}
-
-void __v9fs_fscache_invalidate_page(struct page *page)
-{
-	struct inode *inode = page->mapping->host;
-	struct v9fs_inode *v9inode = V9FS_I(inode);
-
-	BUG_ON(!v9inode->fscache);
-
-	if (PageFsCache(page)) {
-		fscache_wait_on_page_write(v9inode->fscache, page);
-		BUG_ON(!PageLocked(page));
-		fscache_uncache_page(v9inode->fscache, page);
-	}
-}
-
-static void v9fs_vfs_readpage_complete(struct page *page, void *data,
-				       int error)
-{
-	if (!error)
-		SetPageUptodate(page);
-
-	unlock_page(page);
-}
-
-/*
- * __v9fs_readpage_from_fscache - read a page from cache
- *
- * Returns 0 if the pages are in cache and a BIO is submitted,
- * 1 if the pages are not in cache and -error otherwise.
- */
-
-int __v9fs_readpage_from_fscache(struct inode *inode, struct page *page)
-{
-	int ret;
-	const struct v9fs_inode *v9inode = V9FS_I(inode);
-
-	p9_debug(P9_DEBUG_FSC, "inode %p page %p\n", inode, page);
-	if (!v9inode->fscache)
-		return -ENOBUFS;
-
-	ret = fscache_read_or_alloc_page(v9inode->fscache,
-					 page,
-					 v9fs_vfs_readpage_complete,
-					 NULL,
-					 GFP_KERNEL);
-	switch (ret) {
-	case -ENOBUFS:
-	case -ENODATA:
-		p9_debug(P9_DEBUG_FSC, "page/inode not in cache %d\n", ret);
-		return 1;
-	case 0:
-		p9_debug(P9_DEBUG_FSC, "BIO submitted\n");
-		return ret;
-	default:
-		p9_debug(P9_DEBUG_FSC, "ret %d\n", ret);
-		return ret;
-	}
-}
-
-/*
- * __v9fs_readpages_from_fscache - read multiple pages from cache
- *
- * Returns 0 if the pages are in cache and a BIO is submitted,
- * 1 if the pages are not in cache and -error otherwise.
- */
-
-int __v9fs_readpages_from_fscache(struct inode *inode,
-				  struct address_space *mapping,
-				  struct list_head *pages,
-				  unsigned *nr_pages)
-{
-	int ret;
-	const struct v9fs_inode *v9inode = V9FS_I(inode);
-
-	p9_debug(P9_DEBUG_FSC, "inode %p pages %u\n", inode, *nr_pages);
-	if (!v9inode->fscache)
-		return -ENOBUFS;
-
-	ret = fscache_read_or_alloc_pages(v9inode->fscache,
-					  mapping, pages, nr_pages,
-					  v9fs_vfs_readpage_complete,
-					  NULL,
-					  mapping_gfp_mask(mapping));
-	switch (ret) {
-	case -ENOBUFS:
-	case -ENODATA:
-		p9_debug(P9_DEBUG_FSC, "pages/inodes not in cache %d\n", ret);
-		return 1;
-	case 0:
-		BUG_ON(!list_empty(pages));
-		BUG_ON(*nr_pages != 0);
-		p9_debug(P9_DEBUG_FSC, "BIO submitted\n");
-		return ret;
-	default:
-		p9_debug(P9_DEBUG_FSC, "ret %d\n", ret);
-		return ret;
-	}
-}
-
-/*
- * __v9fs_readpage_to_fscache - write a page to the cache
- *
- */
-
-void __v9fs_readpage_to_fscache(struct inode *inode, struct page *page)
-{
-	int ret;
-	const struct v9fs_inode *v9inode = V9FS_I(inode);
-
-	p9_debug(P9_DEBUG_FSC, "inode %p page %p\n", inode, page);
-	ret = fscache_write_page(v9inode->fscache, page,
-				 i_size_read(&v9inode->vfs_inode), GFP_KERNEL);
-	p9_debug(P9_DEBUG_FSC, "ret =  %d\n", ret);
-	if (ret != 0)
-		v9fs_uncache_page(inode, page);
-}
-
-/*
- * wait for a page to complete writing to the cache
- */
-void __v9fs_fscache_wait_on_page_write(struct inode *inode, struct page *page)
-{
-	const struct v9fs_inode *v9inode = V9FS_I(inode);
-	p9_debug(P9_DEBUG_FSC, "inode %p page %p\n", inode, page);
-	if (PageFsCache(page))
-		fscache_wait_on_page_write(v9inode->fscache, page);
-}
diff --git a/fs/9p/cache.h b/fs/9p/cache.h
index 00f107af443e..7480b4b49fea 100644
--- a/fs/9p/cache.h
+++ b/fs/9p/cache.h
@@ -7,9 +7,10 @@
 
 #ifndef _9P_CACHE_H
 #define _9P_CACHE_H
-#ifdef CONFIG_9P_FSCACHE
+#define FSCACHE_USE_NEW_IO_API
 #include <linux/fscache.h>
-#include <linux/spinlock.h>
+
+#ifdef CONFIG_9P_FSCACHE
 
 extern struct fscache_netfs v9fs_cache_netfs;
 extern const struct fscache_cookie_def v9fs_cache_session_index_def;
@@ -27,64 +28,6 @@ extern void v9fs_cache_inode_reset_cookie(struct inode *inode);
 extern int __v9fs_cache_register(void);
 extern void __v9fs_cache_unregister(void);
 
-extern int __v9fs_fscache_release_page(struct page *page, gfp_t gfp);
-extern void __v9fs_fscache_invalidate_page(struct page *page);
-extern int __v9fs_readpage_from_fscache(struct inode *inode,
-					struct page *page);
-extern int __v9fs_readpages_from_fscache(struct inode *inode,
-					 struct address_space *mapping,
-					 struct list_head *pages,
-					 unsigned *nr_pages);
-extern void __v9fs_readpage_to_fscache(struct inode *inode, struct page *page);
-extern void __v9fs_fscache_wait_on_page_write(struct inode *inode,
-					      struct page *page);
-
-static inline int v9fs_fscache_release_page(struct page *page,
-					    gfp_t gfp)
-{
-	return __v9fs_fscache_release_page(page, gfp);
-}
-
-static inline void v9fs_fscache_invalidate_page(struct page *page)
-{
-	__v9fs_fscache_invalidate_page(page);
-}
-
-static inline int v9fs_readpage_from_fscache(struct inode *inode,
-					     struct page *page)
-{
-	return __v9fs_readpage_from_fscache(inode, page);
-}
-
-static inline int v9fs_readpages_from_fscache(struct inode *inode,
-					      struct address_space *mapping,
-					      struct list_head *pages,
-					      unsigned *nr_pages)
-{
-	return __v9fs_readpages_from_fscache(inode, mapping, pages,
-					     nr_pages);
-}
-
-static inline void v9fs_readpage_to_fscache(struct inode *inode,
-					    struct page *page)
-{
-	if (PageFsCache(page))
-		__v9fs_readpage_to_fscache(inode, page);
-}
-
-static inline void v9fs_uncache_page(struct inode *inode, struct page *page)
-{
-	struct v9fs_inode *v9inode = V9FS_I(inode);
-	fscache_uncache_page(v9inode->fscache, page);
-	BUG_ON(PageFsCache(page));
-}
-
-static inline void v9fs_fscache_wait_on_page_write(struct inode *inode,
-						   struct page *page)
-{
-	return __v9fs_fscache_wait_on_page_write(inode, page);
-}
-
 #else /* CONFIG_9P_FSCACHE */
 
 static inline void v9fs_cache_inode_get_cookie(struct inode *inode)
@@ -99,39 +42,5 @@ static inline void v9fs_cache_inode_set_cookie(struct inode *inode, struct file
 {
 }
 
-static inline int v9fs_fscache_release_page(struct page *page,
-					    gfp_t gfp) {
-	return 1;
-}
-
-static inline void v9fs_fscache_invalidate_page(struct page *page) {}
-
-static inline int v9fs_readpage_from_fscache(struct inode *inode,
-					     struct page *page)
-{
-	return -ENOBUFS;
-}
-
-static inline int v9fs_readpages_from_fscache(struct inode *inode,
-					      struct address_space *mapping,
-					      struct list_head *pages,
-					      unsigned *nr_pages)
-{
-	return -ENOBUFS;
-}
-
-static inline void v9fs_readpage_to_fscache(struct inode *inode,
-					    struct page *page)
-{}
-
-static inline void v9fs_uncache_page(struct inode *inode, struct page *page)
-{}
-
-static inline void v9fs_fscache_wait_on_page_write(struct inode *inode,
-						   struct page *page)
-{
-	return;
-}
-
 #endif /* CONFIG_9P_FSCACHE */
 #endif /* _9P_CACHE_H */
diff --git a/fs/9p/v9fs.h b/fs/9p/v9fs.h
index 4ca56c5dd637..92124b235a6d 100644
--- a/fs/9p/v9fs.h
+++ b/fs/9p/v9fs.h
@@ -124,6 +124,15 @@ static inline struct v9fs_inode *V9FS_I(const struct inode *inode)
 	return container_of(inode, struct v9fs_inode, vfs_inode);
 }
 
+static inline struct fscache_cookie *v9fs_inode_cookie(struct v9fs_inode *v9inode)
+{
+#ifdef CONFIG_9P_FSCACHE
+	return v9inode->fscache;
+#else
+	return NULL;
+#endif
+}
+
 extern int v9fs_show_options(struct seq_file *m, struct dentry *root);
 
 struct p9_fid *v9fs_session_init(struct v9fs_session_info *, const char *,
diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c
index 1c4f1b39cc95..2a2368d83868 100644
--- a/fs/9p/vfs_addr.c
+++ b/fs/9p/vfs_addr.c
@@ -19,7 +19,7 @@
 #include <linux/idr.h>
 #include <linux/sched.h>
 #include <linux/uio.h>
-#include <linux/bvec.h>
+#include <linux/netfs.h>
 #include <net/9p/9p.h>
 #include <net/9p/client.h>
 
@@ -29,88 +29,97 @@
 #include "fid.h"
 
 /**
- * v9fs_fid_readpage - read an entire page in from 9P
- * @data: Opaque pointer to the fid being read
- * @page: structure to page
- *
+ * v9fs_req_issue_op - Issue a read from 9P
+ * @subreq: The read to make
  */
-static int v9fs_fid_readpage(void *data, struct page *page)
+static void v9fs_req_issue_op(struct netfs_read_subrequest *subreq)
 {
-	struct p9_fid *fid = data;
-	struct inode *inode = page->mapping->host;
-	struct bio_vec bvec = {.bv_page = page, .bv_len = PAGE_SIZE};
+	struct netfs_read_request *rreq = subreq->rreq;
+	struct p9_fid *fid = rreq->netfs_priv;
 	struct iov_iter to;
-	int retval, err;
+	loff_t pos = subreq->start + subreq->transferred;
+	size_t len = subreq->len   - subreq->transferred;
+	int total, err;
 
-	p9_debug(P9_DEBUG_VFS, "\n");
+	iov_iter_xarray(&to, READ, &rreq->mapping->i_pages, pos, len);
 
-	BUG_ON(!PageLocked(page));
+	total = p9_client_read(fid, pos, &to, &err);
+	netfs_subreq_terminated(subreq, err ?: total, false);
+}
 
-	retval = v9fs_readpage_from_fscache(inode, page);
-	if (retval == 0)
-		return retval;
+/**
+ * v9fs_init_rreq - Initialise a read request
+ * @rreq: The read request
+ * @file: The file being read from
+ */
+static void v9fs_init_rreq(struct netfs_read_request *rreq, struct file *file)
+{
+	struct p9_fid *fid = file->private_data;
 
-	iov_iter_bvec(&to, READ, &bvec, 1, PAGE_SIZE);
+	refcount_inc(&fid->count);
+	rreq->netfs_priv = fid;
+}
 
-	retval = p9_client_read(fid, page_offset(page), &to, &err);
-	if (err) {
-		v9fs_uncache_page(inode, page);
-		retval = err;
-		goto done;
-	}
+/**
+ * v9fs_req_cleanup - Cleanup request initialized by v9fs_init_rreq
+ * @mapping: unused mapping of request to cleanup
+ * @priv: private data to cleanup, a fid, guaranted non-null.
+ */
+static void v9fs_req_cleanup(struct address_space *mapping, void *priv)
+{
+	struct p9_fid *fid = priv;
 
-	zero_user(page, retval, PAGE_SIZE - retval);
-	flush_dcache_page(page);
-	SetPageUptodate(page);
+	p9_client_clunk(fid);
+}
 
-	v9fs_readpage_to_fscache(inode, page);
-	retval = 0;
+/**
+ * v9fs_is_cache_enabled - Determine if caching is enabled for an inode
+ * @inode: The inode to check
+ */
+static bool v9fs_is_cache_enabled(struct inode *inode)
+{
+	struct fscache_cookie *cookie = v9fs_inode_cookie(V9FS_I(inode));
 
-done:
-	unlock_page(page);
-	return retval;
+	return fscache_cookie_enabled(cookie) && !hlist_empty(&cookie->backing_objects);
+}
+
+/**
+ * v9fs_begin_cache_operation - Begin a cache operation for a read
+ * @rreq: The read request
+ */
+static int v9fs_begin_cache_operation(struct netfs_read_request *rreq)
+{
+	struct fscache_cookie *cookie = v9fs_inode_cookie(V9FS_I(rreq->inode));
+
+	return fscache_begin_read_operation(rreq, cookie);
 }
 
+static const struct netfs_read_request_ops v9fs_req_ops = {
+	.init_rreq		= v9fs_init_rreq,
+	.is_cache_enabled	= v9fs_is_cache_enabled,
+	.begin_cache_operation	= v9fs_begin_cache_operation,
+	.issue_op		= v9fs_req_issue_op,
+	.cleanup		= v9fs_req_cleanup,
+};
+
 /**
  * v9fs_vfs_readpage - read an entire page in from 9P
- *
- * @filp: file being read
+ * @file: file being read
  * @page: structure to page
  *
  */
-
-static int v9fs_vfs_readpage(struct file *filp, struct page *page)
+static int v9fs_vfs_readpage(struct file *file, struct page *page)
 {
-	return v9fs_fid_readpage(filp->private_data, page);
+	return netfs_readpage(file, page, &v9fs_req_ops, NULL);
 }
 
 /**
- * v9fs_vfs_readpages - read a set of pages from 9P
- *
- * @filp: file being read
- * @mapping: the address space
- * @pages: list of pages to read
- * @nr_pages: count of pages to read
- *
+ * v9fs_vfs_readahead - read a set of pages from 9P
+ * @ractl: The readahead parameters
  */
-
-static int v9fs_vfs_readpages(struct file *filp, struct address_space *mapping,
-			     struct list_head *pages, unsigned nr_pages)
+static void v9fs_vfs_readahead(struct readahead_control *ractl)
 {
-	int ret = 0;
-	struct inode *inode;
-
-	inode = mapping->host;
-	p9_debug(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, filp);
-
-	ret = v9fs_readpages_from_fscache(inode, mapping, pages, &nr_pages);
-	if (ret == 0)
-		return ret;
-
-	ret = read_cache_pages(mapping, pages, v9fs_fid_readpage,
-			filp->private_data);
-	p9_debug(P9_DEBUG_VFS, "  = %d\n", ret);
-	return ret;
+	netfs_readahead(ractl, &v9fs_req_ops, NULL);
 }
 
 /**
@@ -125,7 +134,14 @@ static int v9fs_release_page(struct page *page, gfp_t gfp)
 {
 	if (PagePrivate(page))
 		return 0;
-	return v9fs_fscache_release_page(page, gfp);
+#ifdef CONFIG_9P_FSCACHE
+	if (PageFsCache(page)) {
+		if (!(gfp & __GFP_DIRECT_RECLAIM) || !(gfp & __GFP_FS))
+			return 0;
+		wait_on_page_fscache(page);
+	}
+#endif
+	return 1;
 }
 
 /**
@@ -138,21 +154,16 @@ static int v9fs_release_page(struct page *page, gfp_t gfp)
 static void v9fs_invalidate_page(struct page *page, unsigned int offset,
 				 unsigned int length)
 {
-	/*
-	 * If called with zero offset, we should release
-	 * the private state assocated with the page
-	 */
-	if (offset == 0 && length == PAGE_SIZE)
-		v9fs_fscache_invalidate_page(page);
+	wait_on_page_fscache(page);
 }
 
 static int v9fs_vfs_writepage_locked(struct page *page)
 {
 	struct inode *inode = page->mapping->host;
 	struct v9fs_inode *v9inode = V9FS_I(inode);
+	loff_t start = page_offset(page);
 	loff_t size = i_size_read(inode);
 	struct iov_iter from;
-	struct bio_vec bvec;
 	int err, len;
 
 	if (page->index == size >> PAGE_SHIFT)
@@ -160,17 +171,14 @@ static int v9fs_vfs_writepage_locked(struct page *page)
 	else
 		len = PAGE_SIZE;
 
-	bvec.bv_page = page;
-	bvec.bv_offset = 0;
-	bvec.bv_len = len;
-	iov_iter_bvec(&from, WRITE, &bvec, 1, len);
+	iov_iter_xarray(&from, WRITE, &page->mapping->i_pages, start, len);
 
 	/* We should have writeback_fid always set */
 	BUG_ON(!v9inode->writeback_fid);
 
 	set_page_writeback(page);
 
-	p9_client_write(v9inode->writeback_fid, page_offset(page), &from, &err);
+	p9_client_write(v9inode->writeback_fid, start, &from, &err);
 
 	end_page_writeback(page);
 	return err;
@@ -208,14 +216,13 @@ static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc)
 static int v9fs_launder_page(struct page *page)
 {
 	int retval;
-	struct inode *inode = page->mapping->host;
 
-	v9fs_fscache_wait_on_page_write(inode, page);
 	if (clear_page_dirty_for_io(page)) {
 		retval = v9fs_vfs_writepage_locked(page);
 		if (retval)
 			return retval;
 	}
+	wait_on_page_fscache(page);
 	return 0;
 }
 
@@ -260,35 +267,24 @@ static int v9fs_write_begin(struct file *filp, struct address_space *mapping,
 			    loff_t pos, unsigned len, unsigned flags,
 			    struct page **pagep, void **fsdata)
 {
-	int retval = 0;
+	int retval;
 	struct page *page;
-	struct v9fs_inode *v9inode;
-	pgoff_t index = pos >> PAGE_SHIFT;
-	struct inode *inode = mapping->host;
-
+	struct v9fs_inode *v9inode = V9FS_I(mapping->host);
 
 	p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
 
-	v9inode = V9FS_I(inode);
-start:
-	page = grab_cache_page_write_begin(mapping, index, flags);
-	if (!page) {
-		retval = -ENOMEM;
-		goto out;
-	}
 	BUG_ON(!v9inode->writeback_fid);
-	if (PageUptodate(page))
-		goto out;
 
-	if (len == PAGE_SIZE)
-		goto out;
+	/* Prefetch area to be written into the cache if we're caching this
+	 * file.  We need to do this before we get a lock on the page in case
+	 * there's more than one writer competing for the same cache block.
+	 */
+	retval = netfs_write_begin(filp, mapping, pos, len, flags, &page, fsdata,
+				   &v9fs_req_ops, NULL);
+	if (retval < 0)
+		return retval;
 
-	retval = v9fs_fid_readpage(v9inode->writeback_fid, page);
-	put_page(page);
-	if (!retval)
-		goto start;
-out:
-	*pagep = page;
+	*pagep = find_subpage(page, pos / PAGE_SIZE);
 	return retval;
 }
 
@@ -305,10 +301,11 @@ static int v9fs_write_end(struct file *filp, struct address_space *mapping,
 		if (unlikely(copied < len)) {
 			copied = 0;
 			goto out;
-		} else if (len == PAGE_SIZE) {
-			SetPageUptodate(page);
 		}
+
+		SetPageUptodate(page);
 	}
+
 	/*
 	 * No need to use i_size_read() here, the i_size
 	 * cannot change under us because we hold the i_mutex.
@@ -328,7 +325,7 @@ static int v9fs_write_end(struct file *filp, struct address_space *mapping,
 
 const struct address_space_operations v9fs_addr_operations = {
 	.readpage = v9fs_vfs_readpage,
-	.readpages = v9fs_vfs_readpages,
+	.readahead = v9fs_vfs_readahead,
 	.set_page_dirty = __set_page_dirty_nobuffers,
 	.writepage = v9fs_vfs_writepage,
 	.write_begin = v9fs_write_begin,
diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index 246235ebdb70..8d5e0ef5518e 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -537,14 +537,23 @@ v9fs_vm_page_mkwrite(struct vm_fault *vmf)
 	p9_debug(P9_DEBUG_VFS, "page %p fid %lx\n",
 		 page, (unsigned long)filp->private_data);
 
+	v9inode = V9FS_I(inode);
+
+	/* Wait for the page to be written to the cache before we allow it to
+	 * be modified.  We then assume the entire page will need writing back.
+	 */
+#ifdef CONFIG_9P_FSCACHE
+	if (PageFsCache(page) &&
+	    wait_on_page_fscache_killable(page) < 0)
+		return VM_FAULT_RETRY;
+#endif
+
 	/* Update file times before taking page lock */
 	file_update_time(filp);
 
-	v9inode = V9FS_I(inode);
-	/* make sure the cache has finished storing the page */
-	v9fs_fscache_wait_on_page_write(inode, page);
 	BUG_ON(!v9inode->writeback_fid);
-	lock_page(page);
+	if (lock_page_killable(page) < 0)
+		return VM_FAULT_RETRY;
 	if (page->mapping != inode->i_mapping)
 		goto out_unlock;
 	wait_for_stable_page(page);

[PATCH v3 3/6] folio: Add a function to change the private data attached to a folio

[David Howells]

Add a function, folio_change_private(), that will change the private data
attached to a folio, without the need to twiddle the private bit or the
refcount.  It assumes that folio_add_private() has already been called on
the page.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://lore.kernel.org/r/162981149911.1901565.17776700811659843340.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/163005743485.2472992.5100702469503007023.stgit@warthog.procyon.org.uk/ # v2
---

 include/linux/pagemap.h |   19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 013cdc90f5fd..569302e4defe 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -229,6 +229,25 @@ static inline void folio_attach_private(struct folio *folio, void *data)
 	folio_set_private(folio);
 }
 
+/**
+ * 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.

[PATCH v3 4/6] folio: Add a function to get the host inode for a folio

[David Howells]

Add a convenience function, folio_inode() that will get the host inode from
a folio's mapping.

Changes:
 ver #2:
  - Fix contradiction between doc and implementation by disallowing use
    with swap caches[1].

Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/YST8OcVNy02Rivbm@casper.infradead.org/ [1]
Link: https://lore.kernel.org/r/162880453171.3369675.3704943108660112470.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/162981151155.1901565.7010079316994382707.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/163005744370.2472992.18324470937328925723.stgit@warthog.procyon.org.uk/ # v2
---

 include/linux/pagemap.h |   14 ++++++++++++++
 mm/page-writeback.c     |    2 +-
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 569302e4defe..fc4b7fcf4cc5 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -203,6 +203,20 @@ 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 is hosting
+ * 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);
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 9c64490171e0..c4d2414a92dd 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -2960,7 +2960,7 @@ EXPORT_SYMBOL_GPL(folio_wait_writeback_killable);
  */
 void folio_wait_stable(struct folio *folio)
 {
-	if (folio->mapping->host->i_sb->s_iflags & SB_I_STABLE_WRITES)
+	if (folio_inode(folio)->i_sb->s_iflags & SB_I_STABLE_WRITES)
 		folio_wait_writeback(folio);
 }
 EXPORT_SYMBOL_GPL(folio_wait_stable);

[PATCH v3 5/6] netfs, 9p, afs, ceph: Use folios

[David Howells]

Convert the netfs helper library to use folios throughout, convert the 9p
and afs filesystems to use folios in their file I/O paths and convert the
ceph filesystem to use just enough folios to compile.

With these changes, afs passes -g quick xfstests.

Changes
=======
ver #2:
 - Add 9p foliation.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: Matthew Wilcox (Oracle) <willy@infradead.org>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Ilya Dryomov <idryomov@gmail.com>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: v9fs-developer@lists.sourceforge.net
cc: linux-afs@lists.infradead.org
cc: ceph-devel@vger.kernel.org
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/2408234.1628687271@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/162877311459.3085614.10601478228012245108.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/162981153551.1901565.3124454657133703341.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/163005745264.2472992.9852048135392188995.stgit@warthog.procyon.org.uk/ # v2
---

 fs/9p/vfs_addr.c           |   78 +++++-----
 fs/9p/vfs_file.c           |   20 +--
 fs/afs/file.c              |   70 +++++----
 fs/afs/internal.h          |   46 +++---
 fs/afs/write.c             |  346 +++++++++++++++++++++-----------------------
 fs/ceph/addr.c             |   80 +++++-----
 fs/netfs/read_helper.c     |  165 +++++++++++----------
 include/linux/netfs.h      |   12 +-
 include/trace/events/afs.h |   21 +--
 9 files changed, 422 insertions(+), 416 deletions(-)

diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c
index 2a2368d83868..10f0e65a6a0a 100644
--- a/fs/9p/vfs_addr.c
+++ b/fs/9p/vfs_addr.c
@@ -110,7 +110,9 @@ static const struct netfs_read_request_ops v9fs_req_ops = {
  */
 static int v9fs_vfs_readpage(struct file *file, struct page *page)
 {
-	return netfs_readpage(file, page, &v9fs_req_ops, NULL);
+	struct folio *folio = page_folio(page);
+
+	return netfs_readpage(file, folio, &v9fs_req_ops, NULL);
 }
 
 /**
@@ -132,13 +134,15 @@ static void v9fs_vfs_readahead(struct readahead_control *ractl)
 
 static int v9fs_release_page(struct page *page, gfp_t gfp)
 {
-	if (PagePrivate(page))
+	struct folio *folio = page_folio(page);
+
+	if (folio_test_private(folio))
 		return 0;
 #ifdef CONFIG_9P_FSCACHE
-	if (PageFsCache(page)) {
+	if (folio_test_fscache(folio)) {
 		if (!(gfp & __GFP_DIRECT_RECLAIM) || !(gfp & __GFP_FS))
 			return 0;
-		wait_on_page_fscache(page);
+		folio_wait_fscache(folio);
 	}
 #endif
 	return 1;
@@ -154,55 +158,55 @@ static int v9fs_release_page(struct page *page, gfp_t gfp)
 static void v9fs_invalidate_page(struct page *page, unsigned int offset,
 				 unsigned int length)
 {
-	wait_on_page_fscache(page);
+	struct folio *folio = page_folio(page);
+
+	folio_wait_fscache(folio);
 }
 
-static int v9fs_vfs_writepage_locked(struct page *page)
+static int v9fs_vfs_write_folio_locked(struct folio *folio)
 {
-	struct inode *inode = page->mapping->host;
+	struct inode *inode = folio_inode(folio);
 	struct v9fs_inode *v9inode = V9FS_I(inode);
-	loff_t start = page_offset(page);
+	loff_t start = folio_pos(folio);
 	loff_t size = i_size_read(inode);
 	struct iov_iter from;
-	int err, len;
+	size_t gran = folio_size(folio), len;
+	int err;
 
-	if (page->index == size >> PAGE_SHIFT)
-		len = size & ~PAGE_MASK;
-	else
-		len = PAGE_SIZE;
+	len = (size >= start + gran) ? gran : size - start;
 
-	iov_iter_xarray(&from, WRITE, &page->mapping->i_pages, start, len);
+	iov_iter_xarray(&from, WRITE, &folio_mapping(folio)->i_pages, start, len);
 
 	/* We should have writeback_fid always set */
 	BUG_ON(!v9inode->writeback_fid);
 
-	set_page_writeback(page);
+	folio_start_writeback(folio);
 
 	p9_client_write(v9inode->writeback_fid, start, &from, &err);
 
-	end_page_writeback(page);
+	folio_end_writeback(folio);
 	return err;
 }
 
 static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc)
 {
+	struct folio *folio = page_folio(page);
 	int retval;
 
-	p9_debug(P9_DEBUG_VFS, "page %p\n", page);
+	p9_debug(P9_DEBUG_VFS, "folio %p\n", folio);
 
-	retval = v9fs_vfs_writepage_locked(page);
+	retval = v9fs_vfs_write_folio_locked(folio);
 	if (retval < 0) {
 		if (retval == -EAGAIN) {
-			redirty_page_for_writepage(wbc, page);
+			folio_redirty_for_writepage(wbc, folio);
 			retval = 0;
 		} else {
-			SetPageError(page);
-			mapping_set_error(page->mapping, retval);
+			mapping_set_error(folio_mapping(folio), retval);
 		}
 	} else
 		retval = 0;
 
-	unlock_page(page);
+	folio_unlock(folio);
 	return retval;
 }
 
@@ -215,14 +219,15 @@ static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc)
 
 static int v9fs_launder_page(struct page *page)
 {
+	struct folio *folio = page_folio(page);
 	int retval;
 
-	if (clear_page_dirty_for_io(page)) {
-		retval = v9fs_vfs_writepage_locked(page);
+	if (folio_clear_dirty_for_io(folio)) {
+		retval = v9fs_vfs_write_folio_locked(folio);
 		if (retval)
 			return retval;
 	}
-	wait_on_page_fscache(page);
+	folio_wait_fscache(folio);
 	return 0;
 }
 
@@ -265,10 +270,10 @@ v9fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 
 static int v9fs_write_begin(struct file *filp, struct address_space *mapping,
 			    loff_t pos, unsigned len, unsigned flags,
-			    struct page **pagep, void **fsdata)
+			    struct page **subpagep, void **fsdata)
 {
 	int retval;
-	struct page *page;
+	struct folio *folio;
 	struct v9fs_inode *v9inode = V9FS_I(mapping->host);
 
 	p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
@@ -279,31 +284,32 @@ static int v9fs_write_begin(struct file *filp, struct address_space *mapping,
 	 * file.  We need to do this before we get a lock on the page in case
 	 * there's more than one writer competing for the same cache block.
 	 */
-	retval = netfs_write_begin(filp, mapping, pos, len, flags, &page, fsdata,
+	retval = netfs_write_begin(filp, mapping, pos, len, flags, &folio, fsdata,
 				   &v9fs_req_ops, NULL);
 	if (retval < 0)
 		return retval;
 
-	*pagep = find_subpage(page, pos / PAGE_SIZE);
+	*subpagep = &folio->page;
 	return retval;
 }
 
 static int v9fs_write_end(struct file *filp, struct address_space *mapping,
 			  loff_t pos, unsigned len, unsigned copied,
-			  struct page *page, void *fsdata)
+			  struct page *subpage, void *fsdata)
 {
 	loff_t last_pos = pos + copied;
-	struct inode *inode = page->mapping->host;
+	struct folio *folio = page_folio(subpage);
+	struct inode *inode = mapping->host;
 
 	p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
 
-	if (!PageUptodate(page)) {
+	if (!folio_test_uptodate(folio)) {
 		if (unlikely(copied < len)) {
 			copied = 0;
 			goto out;
 		}
 
-		SetPageUptodate(page);
+		folio_mark_uptodate(folio);
 	}
 
 	/*
@@ -314,10 +320,10 @@ static int v9fs_write_end(struct file *filp, struct address_space *mapping,
 		inode_add_bytes(inode, last_pos - inode->i_size);
 		i_size_write(inode, last_pos);
 	}
-	set_page_dirty(page);
+	folio_mark_dirty(folio);
 out:
-	unlock_page(page);
-	put_page(page);
+	folio_unlock(folio);
+	folio_put(folio);
 
 	return copied;
 }
diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index 8d5e0ef5518e..69e4176297d4 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -529,13 +529,13 @@ static vm_fault_t
 v9fs_vm_page_mkwrite(struct vm_fault *vmf)
 {
 	struct v9fs_inode *v9inode;
-	struct page *page = vmf->page;
+	struct folio *folio = page_folio(vmf->page);
 	struct file *filp = vmf->vma->vm_file;
 	struct inode *inode = file_inode(filp);
 
 
-	p9_debug(P9_DEBUG_VFS, "page %p fid %lx\n",
-		 page, (unsigned long)filp->private_data);
+	p9_debug(P9_DEBUG_VFS, "folio %p fid %lx\n",
+		 folio, (unsigned long)filp->private_data);
 
 	v9inode = V9FS_I(inode);
 
@@ -543,24 +543,24 @@ v9fs_vm_page_mkwrite(struct vm_fault *vmf)
 	 * be modified.  We then assume the entire page will need writing back.
 	 */
 #ifdef CONFIG_9P_FSCACHE
-	if (PageFsCache(page) &&
-	    wait_on_page_fscache_killable(page) < 0)
-		return VM_FAULT_RETRY;
+	if (folio_test_fscache(folio) &&
+	    folio_wait_fscache_killable(folio) < 0)
+		return VM_FAULT_NOPAGE;
 #endif
 
 	/* Update file times before taking page lock */
 	file_update_time(filp);
 
 	BUG_ON(!v9inode->writeback_fid);
-	if (lock_page_killable(page) < 0)
+	if (folio_lock_killable(folio) < 0)
 		return VM_FAULT_RETRY;
-	if (page->mapping != inode->i_mapping)
+	if (folio_mapping(folio) != inode->i_mapping)
 		goto out_unlock;
-	wait_for_stable_page(page);
+	folio_wait_stable(folio);
 
 	return VM_FAULT_LOCKED;
 out_unlock:
-	unlock_page(page);
+	folio_unlock(folio);
 	return VM_FAULT_NOPAGE;
 }
 
diff --git a/fs/afs/file.c b/fs/afs/file.c
index eb11d047c0ae..58bbcd9ff30f 100644
--- a/fs/afs/file.c
+++ b/fs/afs/file.c
@@ -322,23 +322,24 @@ static void afs_req_issue_op(struct netfs_read_subrequest *subreq)
 
 static int afs_symlink_readpage(struct file *file, struct page *page)
 {
-	struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
+	struct afs_vnode *vnode = AFS_FS_I(page_mapping(page)->host);
 	struct afs_read *fsreq;
+	struct folio *folio = page_folio(page);
 	int ret;
 
 	fsreq = afs_alloc_read(GFP_NOFS);
 	if (!fsreq)
 		return -ENOMEM;
 
-	fsreq->pos	= page->index * PAGE_SIZE;
-	fsreq->len	= PAGE_SIZE;
+	fsreq->pos	= folio_pos(folio);
+	fsreq->len	= folio_size(folio);
 	fsreq->vnode	= vnode;
 	fsreq->iter	= &fsreq->def_iter;
 	iov_iter_xarray(&fsreq->def_iter, READ, &page->mapping->i_pages,
 			fsreq->pos, fsreq->len);
 
 	ret = afs_fetch_data(fsreq->vnode, fsreq);
-	page_endio(page, false, ret);
+	page_endio(&folio->page, false, ret);
 	return ret;
 }
 
@@ -362,7 +363,7 @@ static int afs_begin_cache_operation(struct netfs_read_request *rreq)
 }
 
 static int afs_check_write_begin(struct file *file, loff_t pos, unsigned len,
-				 struct page *page, void **_fsdata)
+				 struct folio *folio, void **_fsdata)
 {
 	struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
 
@@ -385,7 +386,9 @@ const struct netfs_read_request_ops afs_req_ops = {
 
 static int afs_readpage(struct file *file, struct page *page)
 {
-	return netfs_readpage(file, page, &afs_req_ops, NULL);
+	struct folio *folio = page_folio(page);
+
+	return netfs_readpage(file, folio, &afs_req_ops, NULL);
 }
 
 static void afs_readahead(struct readahead_control *ractl)
@@ -397,29 +400,29 @@ static void afs_readahead(struct readahead_control *ractl)
  * Adjust the dirty region of the page on truncation or full invalidation,
  * getting rid of the markers altogether if the region is entirely invalidated.
  */
-static void afs_invalidate_dirty(struct page *page, unsigned int offset,
+static void afs_invalidate_dirty(struct folio *folio, unsigned int offset,
 				 unsigned int length)
 {
-	struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
+	struct afs_vnode *vnode = AFS_FS_I(folio_inode(folio));
 	unsigned long priv;
 	unsigned int f, t, end = offset + length;
 
-	priv = page_private(page);
+	priv = (unsigned long)folio_get_private(folio);
 
 	/* we clean up only if the entire page is being invalidated */
-	if (offset == 0 && length == thp_size(page))
+	if (offset == 0 && length == folio_size(folio))
 		goto full_invalidate;
 
 	 /* If the page was dirtied by page_mkwrite(), the PTE stays writable
 	  * and we don't get another notification to tell us to expand it
 	  * again.
 	  */
-	if (afs_is_page_dirty_mmapped(priv))
+	if (afs_is_folio_dirty_mmapped(priv))
 		return;
 
 	/* We may need to shorten the dirty region */
-	f = afs_page_dirty_from(page, priv);
-	t = afs_page_dirty_to(page, priv);
+	f = afs_folio_dirty_from(folio, priv);
+	t = afs_folio_dirty_to(folio, priv);
 
 	if (t <= offset || f >= end)
 		return; /* Doesn't overlap */
@@ -437,17 +440,17 @@ static void afs_invalidate_dirty(struct page *page, unsigned int offset,
 	if (f == t)
 		goto undirty;
 
-	priv = afs_page_dirty(page, f, t);
-	set_page_private(page, priv);
-	trace_afs_page_dirty(vnode, tracepoint_string("trunc"), page);
+	priv = afs_folio_dirty(folio, f, t);
+	folio_change_private(folio, (void *)priv);
+	trace_afs_folio_dirty(vnode, tracepoint_string("trunc"), folio);
 	return;
 
 undirty:
-	trace_afs_page_dirty(vnode, tracepoint_string("undirty"), page);
-	clear_page_dirty_for_io(page);
+	trace_afs_folio_dirty(vnode, tracepoint_string("undirty"), folio);
+	folio_clear_dirty_for_io(folio);
 full_invalidate:
-	trace_afs_page_dirty(vnode, tracepoint_string("inval"), page);
-	detach_page_private(page);
+	trace_afs_folio_dirty(vnode, tracepoint_string("inval"), folio);
+	folio_detach_private(folio);
 }
 
 /*
@@ -458,14 +461,16 @@ static void afs_invalidate_dirty(struct page *page, unsigned int offset,
 static void afs_invalidatepage(struct page *page, unsigned int offset,
 			       unsigned int length)
 {
-	_enter("{%lu},%u,%u", page->index, offset, length);
+	struct folio *folio = page_folio(page);
+
+	_enter("{%lu},%u,%u", folio_index(folio), offset, length);
 
 	BUG_ON(!PageLocked(page));
 
 	if (PagePrivate(page))
-		afs_invalidate_dirty(page, offset, length);
+		afs_invalidate_dirty(folio, offset, length);
 
-	wait_on_page_fscache(page);
+	folio_wait_fscache(folio);
 	_leave("");
 }
 
@@ -475,30 +480,31 @@ static void afs_invalidatepage(struct page *page, unsigned int offset,
  */
 static int afs_releasepage(struct page *page, gfp_t gfp_flags)
 {
-	struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
+	struct folio *folio = page_folio(page);
+	struct afs_vnode *vnode = AFS_FS_I(folio_inode(folio));
 
 	_enter("{{%llx:%llu}[%lu],%lx},%x",
-	       vnode->fid.vid, vnode->fid.vnode, page->index, page->flags,
+	       vnode->fid.vid, vnode->fid.vnode, folio_index(folio), folio->flags,
 	       gfp_flags);
 
 	/* deny if page is being written to the cache and the caller hasn't
 	 * elected to wait */
 #ifdef CONFIG_AFS_FSCACHE
-	if (PageFsCache(page)) {
+	if (folio_test_fscache(folio)) {
 		if (!(gfp_flags & __GFP_DIRECT_RECLAIM) || !(gfp_flags & __GFP_FS))
 			return false;
-		wait_on_page_fscache(page);
+		folio_wait_fscache(folio);
 	}
 #endif
 
-	if (PagePrivate(page)) {
-		trace_afs_page_dirty(vnode, tracepoint_string("rel"), page);
-		detach_page_private(page);
+	if (folio_test_private(folio)) {
+		trace_afs_folio_dirty(vnode, tracepoint_string("rel"), folio);
+		folio_detach_private(folio);
 	}
 
-	/* indicate that the page can be released */
+	/* Indicate that the folio can be released */
 	_leave(" = T");
-	return 1;
+	return true;
 }
 
 static void afs_add_open_mmap(struct afs_vnode *vnode)
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index 9357c53faa69..aa4c0d6c9780 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -876,59 +876,59 @@ struct afs_vnode_cache_aux {
 } __packed;
 
 /*
- * We use page->private to hold the amount of the page that we've written to,
+ * We use folio->private to hold the amount of the folio that we've written to,
  * splitting the field into two parts.  However, we need to represent a range
- * 0...PAGE_SIZE, so we reduce the resolution if the size of the page
+ * 0...FOLIO_SIZE, so we reduce the resolution if the size of the folio
  * exceeds what we can encode.
  */
 #ifdef CONFIG_64BIT
-#define __AFS_PAGE_PRIV_MASK	0x7fffffffUL
-#define __AFS_PAGE_PRIV_SHIFT	32
-#define __AFS_PAGE_PRIV_MMAPPED	0x80000000UL
+#define __AFS_FOLIO_PRIV_MASK		0x7fffffffUL
+#define __AFS_FOLIO_PRIV_SHIFT		32
+#define __AFS_FOLIO_PRIV_MMAPPED	0x80000000UL
 #else
-#define __AFS_PAGE_PRIV_MASK	0x7fffUL
-#define __AFS_PAGE_PRIV_SHIFT	16
-#define __AFS_PAGE_PRIV_MMAPPED	0x8000UL
+#define __AFS_FOLIO_PRIV_MASK		0x7fffUL
+#define __AFS_FOLIO_PRIV_SHIFT		16
+#define __AFS_FOLIO_PRIV_MMAPPED	0x8000UL
 #endif
 
-static inline unsigned int afs_page_dirty_resolution(struct page *page)
+static inline unsigned int afs_folio_dirty_resolution(struct folio *folio)
 {
-	int shift = thp_order(page) + PAGE_SHIFT - (__AFS_PAGE_PRIV_SHIFT - 1);
+	int shift = folio_shift(folio) - (__AFS_FOLIO_PRIV_SHIFT - 1);
 	return (shift > 0) ? shift : 0;
 }
 
-static inline size_t afs_page_dirty_from(struct page *page, unsigned long priv)
+static inline size_t afs_folio_dirty_from(struct folio *folio, unsigned long priv)
 {
-	unsigned long x = priv & __AFS_PAGE_PRIV_MASK;
+	unsigned long x = priv & __AFS_FOLIO_PRIV_MASK;
 
 	/* The lower bound is inclusive */
-	return x << afs_page_dirty_resolution(page);
+	return x << afs_folio_dirty_resolution(folio);
 }
 
-static inline size_t afs_page_dirty_to(struct page *page, unsigned long priv)
+static inline size_t afs_folio_dirty_to(struct folio *folio, unsigned long priv)
 {
-	unsigned long x = (priv >> __AFS_PAGE_PRIV_SHIFT) & __AFS_PAGE_PRIV_MASK;
+	unsigned long x = (priv >> __AFS_FOLIO_PRIV_SHIFT) & __AFS_FOLIO_PRIV_MASK;
 
 	/* The upper bound is immediately beyond the region */
-	return (x + 1) << afs_page_dirty_resolution(page);
+	return (x + 1) << afs_folio_dirty_resolution(folio);
 }
 
-static inline unsigned long afs_page_dirty(struct page *page, size_t from, size_t to)
+static inline unsigned long afs_folio_dirty(struct folio *folio, size_t from, size_t to)
 {
-	unsigned int res = afs_page_dirty_resolution(page);
+	unsigned int res = afs_folio_dirty_resolution(folio);
 	from >>= res;
 	to = (to - 1) >> res;
-	return (to << __AFS_PAGE_PRIV_SHIFT) | from;
+	return (to << __AFS_FOLIO_PRIV_SHIFT) | from;
 }
 
-static inline unsigned long afs_page_dirty_mmapped(unsigned long priv)
+static inline unsigned long afs_folio_dirty_mmapped(unsigned long priv)
 {
-	return priv | __AFS_PAGE_PRIV_MMAPPED;
+	return priv | __AFS_FOLIO_PRIV_MMAPPED;
 }
 
-static inline bool afs_is_page_dirty_mmapped(unsigned long priv)
+static inline bool afs_is_folio_dirty_mmapped(unsigned long priv)
 {
-	return priv & __AFS_PAGE_PRIV_MMAPPED;
+	return priv & __AFS_FOLIO_PRIV_MMAPPED;
 }
 
 #include <trace/events/afs.h>
diff --git a/fs/afs/write.c b/fs/afs/write.c
index 8b1d9c2f6bec..5319c70e0364 100644
--- a/fs/afs/write.c
+++ b/fs/afs/write.c
@@ -32,7 +32,7 @@ int afs_write_begin(struct file *file, struct address_space *mapping,
 		    struct page **_page, void **fsdata)
 {
 	struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
-	struct page *page;
+	struct folio *folio;
 	unsigned long priv;
 	unsigned f, from;
 	unsigned t, to;
@@ -46,12 +46,12 @@ int afs_write_begin(struct file *file, struct address_space *mapping,
 	 * file.  We need to do this before we get a lock on the page in case
 	 * there's more than one writer competing for the same cache block.
 	 */
-	ret = netfs_write_begin(file, mapping, pos, len, flags, &page, fsdata,
+	ret = netfs_write_begin(file, mapping, pos, len, flags, &folio, fsdata,
 				&afs_req_ops, NULL);
 	if (ret < 0)
 		return ret;
 
-	index = page->index;
+	index = folio_index(folio);
 	from = pos - index * PAGE_SIZE;
 	to = from + len;
 
@@ -59,14 +59,14 @@ int afs_write_begin(struct file *file, struct address_space *mapping,
 	/* See if this page is already partially written in a way that we can
 	 * merge the new write with.
 	 */
-	if (PagePrivate(page)) {
-		priv = page_private(page);
-		f = afs_page_dirty_from(page, priv);
-		t = afs_page_dirty_to(page, priv);
+	if (folio_test_private(folio)) {
+		priv = (unsigned long)folio_get_private(folio);
+		f = afs_folio_dirty_from(folio, priv);
+		t = afs_folio_dirty_to(folio, priv);
 		ASSERTCMP(f, <=, t);
 
-		if (PageWriteback(page)) {
-			trace_afs_page_dirty(vnode, tracepoint_string("alrdy"), page);
+		if (folio_test_writeback(folio)) {
+			trace_afs_folio_dirty(vnode, tracepoint_string("alrdy"), folio);
 			goto flush_conflicting_write;
 		}
 		/* If the file is being filled locally, allow inter-write
@@ -78,7 +78,7 @@ int afs_write_begin(struct file *file, struct address_space *mapping,
 			goto flush_conflicting_write;
 	}
 
-	*_page = page;
+	*_page = &folio->page;
 	_leave(" = 0");
 	return 0;
 
@@ -87,17 +87,17 @@ int afs_write_begin(struct file *file, struct address_space *mapping,
 	 */
 flush_conflicting_write:
 	_debug("flush conflict");
-	ret = write_one_page(page);
+	ret = folio_write_one(folio);
 	if (ret < 0)
 		goto error;
 
-	ret = lock_page_killable(page);
+	ret = folio_lock_killable(folio);
 	if (ret < 0)
 		goto error;
 	goto try_again;
 
 error:
-	put_page(page);
+	folio_put(folio);
 	_leave(" = %d", ret);
 	return ret;
 }
@@ -107,24 +107,25 @@ int afs_write_begin(struct file *file, struct address_space *mapping,
  */
 int afs_write_end(struct file *file, struct address_space *mapping,
 		  loff_t pos, unsigned len, unsigned copied,
-		  struct page *page, void *fsdata)
+		  struct page *subpage, void *fsdata)
 {
+	struct folio *folio = page_folio(subpage);
 	struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
 	unsigned long priv;
-	unsigned int f, from = pos & (thp_size(page) - 1);
+	unsigned int f, from = pos & (folio_size(folio) - 1);
 	unsigned int t, to = from + copied;
 	loff_t i_size, maybe_i_size;
 
 	_enter("{%llx:%llu},{%lx}",
-	       vnode->fid.vid, vnode->fid.vnode, page->index);
+	       vnode->fid.vid, vnode->fid.vnode, folio_index(folio));
 
-	if (!PageUptodate(page)) {
+	if (!folio_test_uptodate(folio)) {
 		if (copied < len) {
 			copied = 0;
 			goto out;
 		}
 
-		SetPageUptodate(page);
+		folio_mark_uptodate(folio);
 	}
 
 	if (copied == 0)
@@ -141,29 +142,29 @@ int afs_write_end(struct file *file, struct address_space *mapping,
 		write_sequnlock(&vnode->cb_lock);
 	}
 
-	if (PagePrivate(page)) {
-		priv = page_private(page);
-		f = afs_page_dirty_from(page, priv);
-		t = afs_page_dirty_to(page, priv);
+	if (folio_test_private(folio)) {
+		priv = (unsigned long)folio_get_private(folio);
+		f = afs_folio_dirty_from(folio, priv);
+		t = afs_folio_dirty_to(folio, priv);
 		if (from < f)
 			f = from;
 		if (to > t)
 			t = to;
-		priv = afs_page_dirty(page, f, t);
-		set_page_private(page, priv);
-		trace_afs_page_dirty(vnode, tracepoint_string("dirty+"), page);
+		priv = afs_folio_dirty(folio, f, t);
+		folio_change_private(folio, (void *)priv);
+		trace_afs_folio_dirty(vnode, tracepoint_string("dirty+"), folio);
 	} else {
-		priv = afs_page_dirty(page, from, to);
-		attach_page_private(page, (void *)priv);
-		trace_afs_page_dirty(vnode, tracepoint_string("dirty"), page);
+		priv = afs_folio_dirty(folio, from, to);
+		folio_attach_private(folio, (void *)priv);
+		trace_afs_folio_dirty(vnode, tracepoint_string("dirty"), folio);
 	}
 
-	if (set_page_dirty(page))
-		_debug("dirtied %lx", page->index);
+	if (folio_mark_dirty(folio))
+		_debug("dirtied %lx", folio_index(folio));
 
 out:
-	unlock_page(page);
-	put_page(page);
+	folio_unlock(folio);
+	folio_put(folio);
 	return copied;
 }
 
@@ -174,40 +175,32 @@ static void afs_kill_pages(struct address_space *mapping,
 			   loff_t start, loff_t len)
 {
 	struct afs_vnode *vnode = AFS_FS_I(mapping->host);
-	struct pagevec pv;
-	unsigned int loop, psize;
+	struct folio *folio;
+	pgoff_t index = start / PAGE_SIZE;
+	pgoff_t last = (start + len - 1) / PAGE_SIZE, next;
 
 	_enter("{%llx:%llu},%llx @%llx",
 	       vnode->fid.vid, vnode->fid.vnode, len, start);
 
-	pagevec_init(&pv);
-
 	do {
-		_debug("kill %llx @%llx", len, start);
-
-		pv.nr = find_get_pages_contig(mapping, start / PAGE_SIZE,
-					      PAGEVEC_SIZE, pv.pages);
-		if (pv.nr == 0)
-			break;
+		_debug("kill %lx (to %lx)", index, last);
 
-		for (loop = 0; loop < pv.nr; loop++) {
-			struct page *page = pv.pages[loop];
+		folio = filemap_get_folio(mapping, index);
+		if (!folio) {
+			next = index + 1;
+			continue;
+		}
 
-			if (page->index * PAGE_SIZE >= start + len)
-				break;
+		next = folio_next_index(folio);
 
-			psize = thp_size(page);
-			start += psize;
-			len -= psize;
-			ClearPageUptodate(page);
-			end_page_writeback(page);
-			lock_page(page);
-			generic_error_remove_page(mapping, page);
-			unlock_page(page);
-		}
+		folio_clear_uptodate(folio);
+		folio_end_writeback(folio);
+		folio_lock(folio);
+		generic_error_remove_page(mapping, &folio->page);
+		folio_unlock(folio);
+		folio_put(folio);
 
-		__pagevec_release(&pv);
-	} while (len > 0);
+	} while (index = next, index <= last);
 
 	_leave("");
 }
@@ -220,37 +213,26 @@ static void afs_redirty_pages(struct writeback_control *wbc,
 			      loff_t start, loff_t len)
 {
 	struct afs_vnode *vnode = AFS_FS_I(mapping->host);
-	struct pagevec pv;
-	unsigned int loop, psize;
+	struct folio *folio;
+	pgoff_t index = start / PAGE_SIZE;
+	pgoff_t last = (start + len - 1) / PAGE_SIZE, next;
 
 	_enter("{%llx:%llu},%llx @%llx",
 	       vnode->fid.vid, vnode->fid.vnode, len, start);
 
-	pagevec_init(&pv);
-
 	do {
 		_debug("redirty %llx @%llx", len, start);
 
-		pv.nr = find_get_pages_contig(mapping, start / PAGE_SIZE,
-					      PAGEVEC_SIZE, pv.pages);
-		if (pv.nr == 0)
-			break;
-
-		for (loop = 0; loop < pv.nr; loop++) {
-			struct page *page = pv.pages[loop];
-
-			if (page->index * PAGE_SIZE >= start + len)
-				break;
-
-			psize = thp_size(page);
-			start += psize;
-			len -= psize;
-			redirty_page_for_writepage(wbc, page);
-			end_page_writeback(page);
+		folio = filemap_get_folio(mapping, index);
+		if (!folio) {
+			next = index + 1;
+			continue;
 		}
 
-		__pagevec_release(&pv);
-	} while (len > 0);
+		folio_redirty_for_writepage(wbc, folio);
+		folio_end_writeback(folio);
+		folio_put(folio);
+	} while (index = next, index <= last);
 
 	_leave("");
 }
@@ -261,7 +243,7 @@ static void afs_redirty_pages(struct writeback_control *wbc,
 static void afs_pages_written_back(struct afs_vnode *vnode, loff_t start, unsigned int len)
 {
 	struct address_space *mapping = vnode->vfs_inode.i_mapping;
-	struct page *page;
+	struct folio *folio;
 	pgoff_t end;
 
 	XA_STATE(xas, &mapping->i_pages, start / PAGE_SIZE);
@@ -272,15 +254,16 @@ static void afs_pages_written_back(struct afs_vnode *vnode, loff_t start, unsign
 	rcu_read_lock();
 
 	end = (start + len - 1) / PAGE_SIZE;
-	xas_for_each(&xas, page, end) {
-		if (!PageWriteback(page)) {
-			kdebug("bad %x @%llx page %lx %lx", len, start, page->index, end);
-			ASSERT(PageWriteback(page));
+	xas_for_each(&xas, folio, end) {
+		if (!folio_test_writeback(folio)) {
+			kdebug("bad %x @%llx page %lx %lx",
+			       len, start, folio_index(folio), end);
+			ASSERT(folio_test_writeback(folio));
 		}
 
-		trace_afs_page_dirty(vnode, tracepoint_string("clear"), page);
-		detach_page_private(page);
-		page_endio(page, true, 0);
+		trace_afs_folio_dirty(vnode, tracepoint_string("clear"), folio);
+		folio_detach_private(folio);
+		page_endio(&folio->page, true, 0);
 	}
 
 	rcu_read_unlock();
@@ -437,7 +420,7 @@ static void afs_extend_writeback(struct address_space *mapping,
 				 unsigned int *_len)
 {
 	struct pagevec pvec;
-	struct page *page;
+	struct folio *folio;
 	unsigned long priv;
 	unsigned int psize, filler = 0;
 	unsigned int f, t;
@@ -456,43 +439,43 @@ static void afs_extend_writeback(struct address_space *mapping,
 		 */
 		rcu_read_lock();
 
-		xas_for_each(&xas, page, ULONG_MAX) {
+		xas_for_each(&xas, folio, ULONG_MAX) {
 			stop = true;
-			if (xas_retry(&xas, page))
+			if (xas_retry(&xas, folio))
 				continue;
-			if (xa_is_value(page))
+			if (xa_is_value(folio))
 				break;
-			if (page->index != index)
+			if (folio_index(folio) != index)
 				break;
 
-			if (!page_cache_get_speculative(page)) {
+			if (!folio_try_get_rcu(folio)) {
 				xas_reset(&xas);
 				continue;
 			}
 
 			/* Has the page moved or been split? */
-			if (unlikely(page != xas_reload(&xas))) {
-				put_page(page);
+			if (unlikely(folio != xas_reload(&xas))) {
+				folio_put(folio);
 				break;
 			}
 
-			if (!trylock_page(page)) {
-				put_page(page);
+			if (!folio_trylock(folio)) {
+				folio_put(folio);
 				break;
 			}
-			if (!PageDirty(page) || PageWriteback(page)) {
-				unlock_page(page);
-				put_page(page);
+			if (!folio_test_dirty(folio) || folio_test_writeback(folio)) {
+				folio_unlock(folio);
+				folio_put(folio);
 				break;
 			}
 
-			psize = thp_size(page);
-			priv = page_private(page);
-			f = afs_page_dirty_from(page, priv);
-			t = afs_page_dirty_to(page, priv);
+			psize = folio_size(folio);
+			priv = (unsigned long)folio_get_private(folio);
+			f = afs_folio_dirty_from(folio, priv);
+			t = afs_folio_dirty_to(folio, priv);
 			if (f != 0 && !new_content) {
-				unlock_page(page);
-				put_page(page);
+				folio_unlock(folio);
+				folio_put(folio);
 				break;
 			}
 
@@ -503,8 +486,8 @@ static void afs_extend_writeback(struct address_space *mapping,
 			else if (t == psize || new_content)
 				stop = false;
 
-			index += thp_nr_pages(page);
-			if (!pagevec_add(&pvec, page))
+			index += folio_nr_pages(folio);
+			if (!pagevec_add(&pvec, &folio->page))
 				break;
 			if (stop)
 				break;
@@ -521,16 +504,16 @@ static void afs_extend_writeback(struct address_space *mapping,
 			break;
 
 		for (i = 0; i < pagevec_count(&pvec); i++) {
-			page = pvec.pages[i];
-			trace_afs_page_dirty(vnode, tracepoint_string("store+"), page);
+			folio = page_folio(pvec.pages[i]);
+			trace_afs_folio_dirty(vnode, tracepoint_string("store+"), folio);
 
-			if (!clear_page_dirty_for_io(page))
+			if (!folio_clear_dirty_for_io(folio))
 				BUG();
-			if (test_set_page_writeback(page))
+			if (folio_start_writeback(folio))
 				BUG();
 
-			*_count -= thp_nr_pages(page);
-			unlock_page(page);
+			*_count -= folio_nr_pages(folio);
+			folio_unlock(folio);
 		}
 
 		pagevec_release(&pvec);
@@ -544,10 +527,10 @@ static void afs_extend_writeback(struct address_space *mapping,
  * Synchronously write back the locked page and any subsequent non-locked dirty
  * pages.
  */
-static ssize_t afs_write_back_from_locked_page(struct address_space *mapping,
-					       struct writeback_control *wbc,
-					       struct page *page,
-					       loff_t start, loff_t end)
+static ssize_t afs_write_back_from_locked_folio(struct address_space *mapping,
+						struct writeback_control *wbc,
+						struct folio *folio,
+						loff_t start, loff_t end)
 {
 	struct afs_vnode *vnode = AFS_FS_I(mapping->host);
 	struct iov_iter iter;
@@ -558,22 +541,22 @@ static ssize_t afs_write_back_from_locked_page(struct address_space *mapping,
 	long count = wbc->nr_to_write;
 	int ret;
 
-	_enter(",%lx,%llx-%llx", page->index, start, end);
+	_enter(",%lx,%llx-%llx", folio_index(folio), start, end);
 
-	if (test_set_page_writeback(page))
+	if (folio_start_writeback(folio))
 		BUG();
 
-	count -= thp_nr_pages(page);
+	count -= folio_nr_pages(folio);
 
 	/* Find all consecutive lockable dirty pages that have contiguous
 	 * written regions, stopping when we find a page that is not
 	 * immediately lockable, is not dirty or is missing, or we reach the
 	 * end of the range.
 	 */
-	priv = page_private(page);
-	offset = afs_page_dirty_from(page, priv);
-	to = afs_page_dirty_to(page, priv);
-	trace_afs_page_dirty(vnode, tracepoint_string("store"), page);
+	priv = (unsigned long)folio_get_private(folio);
+	offset = afs_folio_dirty_from(folio, priv);
+	to = afs_folio_dirty_to(folio, priv);
+	trace_afs_folio_dirty(vnode, tracepoint_string("store"), folio);
 
 	len = to - offset;
 	start += offset;
@@ -586,7 +569,7 @@ static ssize_t afs_write_back_from_locked_page(struct address_space *mapping,
 		max_len = min_t(unsigned long long, max_len, i_size - start);
 
 		if (len < max_len &&
-		    (to == thp_size(page) || new_content))
+		    (to == folio_size(folio) || new_content))
 			afs_extend_writeback(mapping, vnode, &count,
 					     start, max_len, new_content, &len);
 		len = min_t(loff_t, len, max_len);
@@ -596,7 +579,7 @@ static ssize_t afs_write_back_from_locked_page(struct address_space *mapping,
 	 * set; the first page is still locked at this point, but all the rest
 	 * have been unlocked.
 	 */
-	unlock_page(page);
+	folio_unlock(folio);
 
 	if (start < i_size) {
 		_debug("write back %x @%llx [%llx]", len, start, i_size);
@@ -657,16 +640,17 @@ static ssize_t afs_write_back_from_locked_page(struct address_space *mapping,
  * write a page back to the server
  * - the caller locked the page for us
  */
-int afs_writepage(struct page *page, struct writeback_control *wbc)
+int afs_writepage(struct page *subpage, struct writeback_control *wbc)
 {
+	struct folio *folio = page_folio(subpage);
 	ssize_t ret;
 	loff_t start;
 
-	_enter("{%lx},", page->index);
+	_enter("{%lx},", folio_index(folio));
 
-	start = page->index * PAGE_SIZE;
-	ret = afs_write_back_from_locked_page(page->mapping, wbc, page,
-					      start, LLONG_MAX - start);
+	start = folio_index(folio) * PAGE_SIZE;
+	ret = afs_write_back_from_locked_folio(folio_mapping(folio), wbc,
+					       folio, start, LLONG_MAX - start);
 	if (ret < 0) {
 		_leave(" = %zd", ret);
 		return ret;
@@ -683,7 +667,8 @@ static int afs_writepages_region(struct address_space *mapping,
 				 struct writeback_control *wbc,
 				 loff_t start, loff_t end, loff_t *_next)
 {
-	struct page *page;
+	struct folio *folio;
+	struct page *head_page;
 	ssize_t ret;
 	int n;
 
@@ -693,13 +678,14 @@ static int afs_writepages_region(struct address_space *mapping,
 		pgoff_t index = start / PAGE_SIZE;
 
 		n = find_get_pages_range_tag(mapping, &index, end / PAGE_SIZE,
-					     PAGECACHE_TAG_DIRTY, 1, &page);
+					     PAGECACHE_TAG_DIRTY, 1, &head_page);
 		if (!n)
 			break;
 
-		start = (loff_t)page->index * PAGE_SIZE; /* May regress with THPs */
+		folio = page_folio(head_page);
+		start = folio_pos(folio); /* May regress with THPs */
 
-		_debug("wback %lx", page->index);
+		_debug("wback %lx", folio_index(folio));
 
 		/* At this point we hold neither the i_pages lock nor the
 		 * page lock: the page may be truncated or invalidated
@@ -707,37 +693,38 @@ static int afs_writepages_region(struct address_space *mapping,
 		 * back from swapper_space to tmpfs file mapping
 		 */
 		if (wbc->sync_mode != WB_SYNC_NONE) {
-			ret = lock_page_killable(page);
+			ret = folio_lock_killable(folio);
 			if (ret < 0) {
-				put_page(page);
+				folio_put(folio);
 				return ret;
 			}
 		} else {
-			if (!trylock_page(page)) {
-				put_page(page);
+			if (!folio_trylock(folio)) {
+				folio_put(folio);
 				return 0;
 			}
 		}
 
-		if (page->mapping != mapping || !PageDirty(page)) {
-			start += thp_size(page);
-			unlock_page(page);
-			put_page(page);
+		if (folio_mapping(folio) != mapping ||
+		    !folio_test_dirty(folio)) {
+			start += folio_size(folio);
+			folio_unlock(folio);
+			folio_put(folio);
 			continue;
 		}
 
-		if (PageWriteback(page)) {
-			unlock_page(page);
+		if (folio_test_writeback(folio)) {
+			folio_unlock(folio);
 			if (wbc->sync_mode != WB_SYNC_NONE)
-				wait_on_page_writeback(page);
-			put_page(page);
+				folio_wait_writeback(folio);
+			folio_put(folio);
 			continue;
 		}
 
-		if (!clear_page_dirty_for_io(page))
+		if (!folio_clear_dirty_for_io(folio))
 			BUG();
-		ret = afs_write_back_from_locked_page(mapping, wbc, page, start, end);
-		put_page(page);
+		ret = afs_write_back_from_locked_folio(mapping, wbc, folio, start, end);
+		folio_put(folio);
 		if (ret < 0) {
 			_leave(" = %zd", ret);
 			return ret;
@@ -862,7 +849,6 @@ int afs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
 vm_fault_t afs_page_mkwrite(struct vm_fault *vmf)
 {
 	struct folio *folio = page_folio(vmf->page);
-	struct page *page = &folio->page;
 	struct file *file = vmf->vma->vm_file;
 	struct inode *inode = file_inode(file);
 	struct afs_vnode *vnode = AFS_FS_I(inode);
@@ -870,7 +856,7 @@ vm_fault_t afs_page_mkwrite(struct vm_fault *vmf)
 	unsigned long priv;
 	vm_fault_t ret = VM_FAULT_RETRY;
 
-	_enter("{{%llx:%llu}},{%lx}", vnode->fid.vid, vnode->fid.vnode, page->index);
+	_enter("{{%llx:%llu}},{%lx}", vnode->fid.vid, vnode->fid.vnode, folio_index(folio));
 
 	afs_validate(vnode, af->key);
 
@@ -880,18 +866,18 @@ vm_fault_t afs_page_mkwrite(struct vm_fault *vmf)
 	 * be modified.  We then assume the entire page will need writing back.
 	 */
 #ifdef CONFIG_AFS_FSCACHE
-	if (PageFsCache(page) &&
-	    wait_on_page_fscache_killable(page) < 0)
+	if (folio_test_fscache(folio) &&
+	    folio_wait_fscache_killable(folio) < 0)
 		goto out;
 #endif
 
 	if (folio_wait_writeback_killable(folio))
 		goto out;
 
-	if (lock_page_killable(page) < 0)
+	if (folio_lock_killable(folio) < 0)
 		goto out;
 
-	/* We mustn't change page->private until writeback is complete as that
+	/* We mustn't change folio->private until writeback is complete as that
 	 * details the portion of the page we need to write back and we might
 	 * need to redirty the page if there's a problem.
 	 */
@@ -900,14 +886,14 @@ vm_fault_t afs_page_mkwrite(struct vm_fault *vmf)
 		goto out;
 	}
 
-	priv = afs_page_dirty(page, 0, thp_size(page));
-	priv = afs_page_dirty_mmapped(priv);
-	if (PagePrivate(page)) {
-		set_page_private(page, priv);
-		trace_afs_page_dirty(vnode, tracepoint_string("mkwrite+"), page);
+	priv = afs_folio_dirty(folio, 0, folio_size(folio));
+	priv = afs_folio_dirty_mmapped(priv);
+	if (folio_test_private(folio)) {
+		folio_change_private(folio, (void *)priv);
+		trace_afs_folio_dirty(vnode, tracepoint_string("mkwrite+"), folio);
 	} else {
-		attach_page_private(page, (void *)priv);
-		trace_afs_page_dirty(vnode, tracepoint_string("mkwrite"), page);
+		folio_attach_private(folio, (void *)priv);
+		trace_afs_folio_dirty(vnode, tracepoint_string("mkwrite"), folio);
 	}
 	file_update_time(file);
 
@@ -948,38 +934,38 @@ void afs_prune_wb_keys(struct afs_vnode *vnode)
 /*
  * Clean up a page during invalidation.
  */
-int afs_launder_page(struct page *page)
+int afs_launder_page(struct page *subpage)
 {
-	struct address_space *mapping = page->mapping;
-	struct afs_vnode *vnode = AFS_FS_I(mapping->host);
+	struct folio *folio = page_folio(subpage);
+	struct afs_vnode *vnode = AFS_FS_I(folio_inode(folio));
 	struct iov_iter iter;
 	struct bio_vec bv[1];
 	unsigned long priv;
 	unsigned int f, t;
 	int ret = 0;
 
-	_enter("{%lx}", page->index);
+	_enter("{%lx}", folio_index(folio));
 
-	priv = page_private(page);
-	if (clear_page_dirty_for_io(page)) {
+	priv = (unsigned long)folio_get_private(folio);
+	if (folio_clear_dirty_for_io(folio)) {
 		f = 0;
-		t = thp_size(page);
-		if (PagePrivate(page)) {
-			f = afs_page_dirty_from(page, priv);
-			t = afs_page_dirty_to(page, priv);
+		t = folio_size(folio);
+		if (folio_test_private(folio)) {
+			f = afs_folio_dirty_from(folio, priv);
+			t = afs_folio_dirty_to(folio, priv);
 		}
 
-		bv[0].bv_page = page;
+		bv[0].bv_page = &folio->page;
 		bv[0].bv_offset = f;
 		bv[0].bv_len = t - f;
 		iov_iter_bvec(&iter, WRITE, bv, 1, bv[0].bv_len);
 
-		trace_afs_page_dirty(vnode, tracepoint_string("launder"), page);
-		ret = afs_store_data(vnode, &iter, page_offset(page) + f, true);
+		trace_afs_folio_dirty(vnode, tracepoint_string("launder"), folio);
+		ret = afs_store_data(vnode, &iter, folio_pos(folio) + f, true);
 	}
 
-	trace_afs_page_dirty(vnode, tracepoint_string("laundered"), page);
-	detach_page_private(page);
-	wait_on_page_fscache(page);
+	trace_afs_folio_dirty(vnode, tracepoint_string("laundered"), folio);
+	folio_detach_private(folio);
+	folio_wait_fscache(folio);
 	return ret;
 }
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 99b80b5c7a93..04bbe853bcb1 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -63,7 +63,7 @@
 	 (CONGESTION_ON_THRESH(congestion_kb) >> 2))
 
 static int ceph_netfs_check_write_begin(struct file *file, loff_t pos, unsigned int len,
-					struct page *page, void **_fsdata);
+					struct folio *folio, void **_fsdata);
 
 static inline struct ceph_snap_context *page_snap_context(struct page *page)
 {
@@ -317,13 +317,14 @@ static const struct netfs_read_request_ops ceph_netfs_read_ops = {
 };
 
 /* read a single page, without unlocking it. */
-static int ceph_readpage(struct file *file, struct page *page)
+static int ceph_readpage(struct file *file, struct page *subpage)
 {
+	struct folio *folio = page_folio(subpage);
 	struct inode *inode = file_inode(file);
 	struct ceph_inode_info *ci = ceph_inode(inode);
 	struct ceph_vino vino = ceph_vino(inode);
-	u64 off = page_offset(page);
-	u64 len = thp_size(page);
+	size_t len = folio_size(folio);
+	u64 off = folio_file_pos(folio);
 
 	if (ci->i_inline_version != CEPH_INLINE_NONE) {
 		/*
@@ -331,19 +332,19 @@ static int ceph_readpage(struct file *file, struct page *page)
 		 * into page cache while getting Fcr caps.
 		 */
 		if (off == 0) {
-			unlock_page(page);
+			folio_unlock(folio);
 			return -EINVAL;
 		}
-		zero_user_segment(page, 0, thp_size(page));
-		SetPageUptodate(page);
-		unlock_page(page);
+		zero_user_segment(&folio->page, 0, folio_size(folio));
+		folio_mark_uptodate(folio);
+		folio_unlock(folio);
 		return 0;
 	}
 
-	dout("readpage ino %llx.%llx file %p off %llu len %llu page %p index %lu\n",
-	     vino.ino, vino.snap, file, off, len, page, page->index);
+	dout("readpage ino %llx.%llx file %p off %llu len %zu folio %p index %lu\n",
+	     vino.ino, vino.snap, file, off, len, folio, folio_index(folio));
 
-	return netfs_readpage(file, page, &ceph_netfs_read_ops, NULL);
+	return netfs_readpage(file, folio, &ceph_netfs_read_ops, NULL);
 }
 
 static void ceph_readahead(struct readahead_control *ractl)
@@ -1187,18 +1188,18 @@ ceph_find_incompatible(struct page *page)
 }
 
 static int ceph_netfs_check_write_begin(struct file *file, loff_t pos, unsigned int len,
-					struct page *page, void **_fsdata)
+					struct folio *folio, void **_fsdata)
 {
 	struct inode *inode = file_inode(file);
 	struct ceph_inode_info *ci = ceph_inode(inode);
 	struct ceph_snap_context *snapc;
 
-	snapc = ceph_find_incompatible(page);
+	snapc = ceph_find_incompatible(folio_page(folio, 0));
 	if (snapc) {
 		int r;
 
-		unlock_page(page);
-		put_page(page);
+		folio_unlock(folio);
+		folio_put(folio);
 		if (IS_ERR(snapc))
 			return PTR_ERR(snapc);
 
@@ -1216,12 +1217,12 @@ static int ceph_netfs_check_write_begin(struct file *file, loff_t pos, unsigned
  * clean, or already dirty within the same snap context.
  */
 static int ceph_write_begin(struct file *file, struct address_space *mapping,
-			    loff_t pos, unsigned len, unsigned flags,
+			    loff_t pos, unsigned len, unsigned aop_flags,
 			    struct page **pagep, void **fsdata)
 {
 	struct inode *inode = file_inode(file);
 	struct ceph_inode_info *ci = ceph_inode(inode);
-	struct page *page = NULL;
+	struct folio *folio = NULL;
 	pgoff_t index = pos >> PAGE_SHIFT;
 	int r;
 
@@ -1230,39 +1231,43 @@ static int ceph_write_begin(struct file *file, struct address_space *mapping,
 	 * for inline_version sent to the MDS.
 	 */
 	if (ci->i_inline_version != CEPH_INLINE_NONE) {
-		page = grab_cache_page_write_begin(mapping, index, flags);
-		if (!page)
+		unsigned int fgp_flags = FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE;
+		if (aop_flags & AOP_FLAG_NOFS)
+			fgp_flags |= FGP_NOFS;
+		folio = __filemap_get_folio(mapping, index, fgp_flags,
+					    mapping_gfp_mask(mapping));
+		if (!folio)
 			return -ENOMEM;
 
 		/*
 		 * The inline_version on a new inode is set to 1. If that's the
-		 * case, then the page is brand new and isn't yet Uptodate.
+		 * case, then the folio is brand new and isn't yet Uptodate.
 		 */
 		r = 0;
 		if (index == 0 && ci->i_inline_version != 1) {
-			if (!PageUptodate(page)) {
+			if (!folio_test_uptodate(folio)) {
 				WARN_ONCE(1, "ceph: write_begin called on still-inlined inode (inline_version %llu)!\n",
 					  ci->i_inline_version);
 				r = -EINVAL;
 			}
 			goto out;
 		}
-		zero_user_segment(page, 0, thp_size(page));
-		SetPageUptodate(page);
+		zero_user_segment(&folio->page, 0, folio_size(folio));
+		folio_mark_uptodate(folio);
 		goto out;
 	}
 
-	r = netfs_write_begin(file, inode->i_mapping, pos, len, 0, &page, NULL,
+	r = netfs_write_begin(file, inode->i_mapping, pos, len, 0, &folio, NULL,
 			      &ceph_netfs_read_ops, NULL);
 out:
 	if (r == 0)
-		wait_on_page_fscache(page);
+		folio_wait_fscache(folio);
 	if (r < 0) {
-		if (page)
-			put_page(page);
+		if (folio)
+			folio_put(folio);
 	} else {
-		WARN_ON_ONCE(!PageLocked(page));
-		*pagep = page;
+		WARN_ON_ONCE(!folio_test_locked(folio));
+		*pagep = &folio->page;
 	}
 	return r;
 }
@@ -1273,32 +1278,33 @@ static int ceph_write_begin(struct file *file, struct address_space *mapping,
  */
 static int ceph_write_end(struct file *file, struct address_space *mapping,
 			  loff_t pos, unsigned len, unsigned copied,
-			  struct page *page, void *fsdata)
+			  struct page *subpage, void *fsdata)
 {
+	struct folio *folio = page_folio(subpage);
 	struct inode *inode = file_inode(file);
 	bool check_cap = false;
 
-	dout("write_end file %p inode %p page %p %d~%d (%d)\n", file,
-	     inode, page, (int)pos, (int)copied, (int)len);
+	dout("write_end file %p inode %p folio %p %d~%d (%d)\n", file,
+	     inode, folio, (int)pos, (int)copied, (int)len);
 
-	if (!PageUptodate(page)) {
+	if (!folio_test_uptodate(folio)) {
 		/* just return that nothing was copied on a short copy */
 		if (copied < len) {
 			copied = 0;
 			goto out;
 		}
-		SetPageUptodate(page);
+		folio_mark_uptodate(folio);
 	}
 
 	/* did file size increase? */
 	if (pos+copied > i_size_read(inode))
 		check_cap = ceph_inode_set_size(inode, pos+copied);
 
-	set_page_dirty(page);
+	folio_mark_dirty(folio);
 
 out:
-	unlock_page(page);
-	put_page(page);
+	folio_unlock(folio);
+	folio_put(folio);
 
 	if (check_cap)
 		ceph_check_caps(ceph_inode(inode), CHECK_CAPS_AUTHONLY, NULL);
diff --git a/fs/netfs/read_helper.c b/fs/netfs/read_helper.c
index 994ec22d4040..9320a42dfaf9 100644
--- a/fs/netfs/read_helper.c
+++ b/fs/netfs/read_helper.c
@@ -230,7 +230,7 @@ static void netfs_rreq_completed(struct netfs_read_request *rreq, bool was_async
 
 /*
  * Deal with the completion of writing the data to the cache.  We have to clear
- * the PG_fscache bits on the pages involved and release the caller's ref.
+ * the PG_fscache bits on the folios involved and release the caller's ref.
  *
  * May be called in softirq mode and we inherit a ref from the caller.
  */
@@ -238,7 +238,7 @@ static void netfs_rreq_unmark_after_write(struct netfs_read_request *rreq,
 					  bool was_async)
 {
 	struct netfs_read_subrequest *subreq;
-	struct page *page;
+	struct folio *folio;
 	pgoff_t unlocked = 0;
 	bool have_unlocked = false;
 
@@ -247,14 +247,14 @@ static void netfs_rreq_unmark_after_write(struct netfs_read_request *rreq,
 	list_for_each_entry(subreq, &rreq->subrequests, rreq_link) {
 		XA_STATE(xas, &rreq->mapping->i_pages, subreq->start / PAGE_SIZE);
 
-		xas_for_each(&xas, page, (subreq->start + subreq->len - 1) / PAGE_SIZE) {
+		xas_for_each(&xas, folio, (subreq->start + subreq->len - 1) / PAGE_SIZE) {
 			/* We might have multiple writes from the same huge
-			 * page, but we mustn't unlock a page more than once.
+			 * folio, but we mustn't unlock a folio more than once.
 			 */
-			if (have_unlocked && page->index <= unlocked)
+			if (have_unlocked && folio_index(folio) <= unlocked)
 				continue;
-			unlocked = page->index;
-			end_page_fscache(page);
+			unlocked = folio_index(folio);
+			folio_end_fscache(folio);
 			have_unlocked = true;
 		}
 	}
@@ -367,18 +367,17 @@ static void netfs_rreq_write_to_cache(struct netfs_read_request *rreq,
 }
 
 /*
- * Unlock the pages in a read operation.  We need to set PG_fscache on any
- * pages we're going to write back before we unlock them.
+ * Unlock the folios in a read operation.  We need to set PG_fscache on any
+ * folios we're going to write back before we unlock them.
  */
 static void netfs_rreq_unlock(struct netfs_read_request *rreq)
 {
 	struct netfs_read_subrequest *subreq;
-	struct page *page;
+	struct folio *folio;
 	unsigned int iopos, account = 0;
 	pgoff_t start_page = rreq->start / PAGE_SIZE;
 	pgoff_t last_page = ((rreq->start + rreq->len) / PAGE_SIZE) - 1;
 	bool subreq_failed = false;
-	int i;
 
 	XA_STATE(xas, &rreq->mapping->i_pages, start_page);
 
@@ -403,9 +402,9 @@ static void netfs_rreq_unlock(struct netfs_read_request *rreq)
 	trace_netfs_rreq(rreq, netfs_rreq_trace_unlock);
 
 	rcu_read_lock();
-	xas_for_each(&xas, page, last_page) {
-		unsigned int pgpos = (page->index - start_page) * PAGE_SIZE;
-		unsigned int pgend = pgpos + thp_size(page);
+	xas_for_each(&xas, folio, last_page) {
+		unsigned int pgpos = (folio_index(folio) - start_page) * PAGE_SIZE;
+		unsigned int pgend = pgpos + folio_size(folio);
 		bool pg_failed = false;
 
 		for (;;) {
@@ -414,7 +413,7 @@ static void netfs_rreq_unlock(struct netfs_read_request *rreq)
 				break;
 			}
 			if (test_bit(NETFS_SREQ_WRITE_TO_CACHE, &subreq->flags))
-				set_page_fscache(page);
+				folio_start_fscache(folio);
 			pg_failed |= subreq_failed;
 			if (pgend < iopos + subreq->len)
 				break;
@@ -433,17 +432,16 @@ static void netfs_rreq_unlock(struct netfs_read_request *rreq)
 		}
 
 		if (!pg_failed) {
-			for (i = 0; i < thp_nr_pages(page); i++)
-				flush_dcache_page(page);
-			SetPageUptodate(page);
+			flush_dcache_folio(folio);
+			folio_mark_uptodate(folio);
 		}
 
-		if (!test_bit(NETFS_RREQ_DONT_UNLOCK_PAGES, &rreq->flags)) {
-			if (page->index == rreq->no_unlock_page &&
-			    test_bit(NETFS_RREQ_NO_UNLOCK_PAGE, &rreq->flags))
+		if (!test_bit(NETFS_RREQ_DONT_UNLOCK_FOLIOS, &rreq->flags)) {
+			if (folio_index(folio) == rreq->no_unlock_folio &&
+			    test_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags))
 				_debug("no unlock");
 			else
-				unlock_page(page);
+				folio_unlock(folio);
 		}
 	}
 	rcu_read_unlock();
@@ -876,7 +874,6 @@ void netfs_readahead(struct readahead_control *ractl,
 		     void *netfs_priv)
 {
 	struct netfs_read_request *rreq;
-	struct page *page;
 	unsigned int debug_index = 0;
 	int ret;
 
@@ -911,11 +908,11 @@ void netfs_readahead(struct readahead_control *ractl,
 
 	} while (rreq->submitted < rreq->len);
 
-	/* Drop the refs on the pages here rather than in the cache or
+	/* Drop the refs on the folios here rather than in the cache or
 	 * filesystem.  The locks will be dropped in netfs_rreq_unlock().
 	 */
-	while ((page = readahead_page(ractl)))
-		put_page(page);
+	while (readahead_folio(ractl))
+		;
 
 	/* If we decrement nr_rd_ops to 0, the ref belongs to us. */
 	if (atomic_dec_and_test(&rreq->nr_rd_ops))
@@ -935,7 +932,7 @@ EXPORT_SYMBOL(netfs_readahead);
 /**
  * netfs_readpage - Helper to manage a readpage request
  * @file: The file to read from
- * @page: The page to read
+ * @folio: The folio to read
  * @ops: The network filesystem's operations for the helper to use
  * @netfs_priv: Private netfs data to be retained in the request
  *
@@ -950,7 +947,7 @@ EXPORT_SYMBOL(netfs_readahead);
  * This is usable whether or not caching is enabled.
  */
 int netfs_readpage(struct file *file,
-		   struct page *page,
+		   struct folio *folio,
 		   const struct netfs_read_request_ops *ops,
 		   void *netfs_priv)
 {
@@ -958,23 +955,23 @@ int netfs_readpage(struct file *file,
 	unsigned int debug_index = 0;
 	int ret;
 
-	_enter("%lx", page_index(page));
+	_enter("%lx", folio_index(folio));
 
 	rreq = netfs_alloc_read_request(ops, netfs_priv, file);
 	if (!rreq) {
 		if (netfs_priv)
-			ops->cleanup(netfs_priv, page_file_mapping(page));
-		unlock_page(page);
+			ops->cleanup(netfs_priv, folio_file_mapping(folio));
+		folio_unlock(folio);
 		return -ENOMEM;
 	}
-	rreq->mapping	= page_file_mapping(page);
-	rreq->start	= page_file_offset(page);
-	rreq->len	= thp_size(page);
+	rreq->mapping	= folio_file_mapping(folio);
+	rreq->start	= folio_file_pos(folio);
+	rreq->len	= folio_size(folio);
 
 	if (ops->begin_cache_operation) {
 		ret = ops->begin_cache_operation(rreq);
 		if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS) {
-			unlock_page(page);
+			folio_unlock(folio);
 			goto out;
 		}
 	}
@@ -1012,40 +1009,40 @@ int netfs_readpage(struct file *file,
 EXPORT_SYMBOL(netfs_readpage);
 
 /**
- * netfs_skip_page_read - prep a page for writing without reading first
- * @page: page being prepared
+ * netfs_skip_folio_read - prep a folio for writing without reading first
+ * @folio: The folio being prepared
  * @pos: starting position for the write
  * @len: length of write
  *
  * In some cases, write_begin doesn't need to read at all:
- * - full page write
- * - write that lies in a page that is completely beyond EOF
- * - write that covers the the page from start to EOF or beyond it
+ * - full folio write
+ * - write that lies in a folio that is completely beyond EOF
+ * - write that covers the folio from start to EOF or beyond it
  *
  * If any of these criteria are met, then zero out the unwritten parts
- * of the page and return true. Otherwise, return false.
+ * of the folio and return true. Otherwise, return false.
  */
-static bool netfs_skip_page_read(struct page *page, loff_t pos, size_t len)
+static bool netfs_skip_folio_read(struct folio *folio, loff_t pos, size_t len)
 {
-	struct inode *inode = page->mapping->host;
+	struct inode *inode = folio_inode(folio);
 	loff_t i_size = i_size_read(inode);
-	size_t offset = offset_in_thp(page, pos);
+	size_t offset = offset_in_folio(folio, pos);
 
-	/* Full page write */
-	if (offset == 0 && len >= thp_size(page))
+	/* Full folio write */
+	if (offset == 0 && len >= folio_size(folio))
 		return true;
 
-	/* pos beyond last page in the file */
+	/* pos beyond last folio in the file */
 	if (pos - offset >= i_size)
 		goto zero_out;
 
-	/* Write that covers from the start of the page to EOF or beyond */
+	/* Write that covers from the start of the folio to EOF or beyond */
 	if (offset == 0 && (pos + len) >= i_size)
 		goto zero_out;
 
 	return false;
 zero_out:
-	zero_user_segments(page, 0, offset, offset + len, thp_size(page));
+	zero_user_segments(&folio->page, 0, offset, offset + len, folio_size(folio));
 	return true;
 }
 
@@ -1054,9 +1051,9 @@ static bool netfs_skip_page_read(struct page *page, loff_t pos, size_t len)
  * @file: The file to read from
  * @mapping: The mapping to read from
  * @pos: File position at which the write will begin
- * @len: The length of the write (may extend beyond the end of the page chosen)
- * @flags: AOP_* flags
- * @_page: Where to put the resultant page
+ * @len: The length of the write (may extend beyond the end of the folio chosen)
+ * @aop_flags: AOP_* flags
+ * @_folio: Where to put the resultant folio
  * @_fsdata: Place for the netfs to store a cookie
  * @ops: The network filesystem's operations for the helper to use
  * @netfs_priv: Private netfs data to be retained in the request
@@ -1072,37 +1069,41 @@ static bool netfs_skip_page_read(struct page *page, loff_t pos, size_t len)
  * issue_op, is mandatory.
  *
  * The check_write_begin() operation can be provided to check for and flush
- * conflicting writes once the page is grabbed and locked.  It is passed a
+ * conflicting writes once the folio is grabbed and locked.  It is passed a
  * pointer to the fsdata cookie that gets returned to the VM to be passed to
  * write_end.  It is permitted to sleep.  It should return 0 if the request
- * should go ahead; unlock the page and return -EAGAIN to cause the page to be
- * regot; or return an error.
+ * should go ahead; unlock the folio and return -EAGAIN to cause the folio to
+ * be regot; or return an error.
  *
  * This is usable whether or not caching is enabled.
  */
 int netfs_write_begin(struct file *file, struct address_space *mapping,
-		      loff_t pos, unsigned int len, unsigned int flags,
-		      struct page **_page, void **_fsdata,
+		      loff_t pos, unsigned int len, unsigned int aop_flags,
+		      struct folio **_folio, void **_fsdata,
 		      const struct netfs_read_request_ops *ops,
 		      void *netfs_priv)
 {
 	struct netfs_read_request *rreq;
-	struct page *page, *xpage;
+	struct folio *folio;
 	struct inode *inode = file_inode(file);
-	unsigned int debug_index = 0;
+	unsigned int debug_index = 0, fgp_flags;
 	pgoff_t index = pos >> PAGE_SHIFT;
 	int ret;
 
 	DEFINE_READAHEAD(ractl, file, NULL, mapping, index);
 
 retry:
-	page = grab_cache_page_write_begin(mapping, index, flags);
-	if (!page)
+	fgp_flags = FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE;
+	if (aop_flags & AOP_FLAG_NOFS)
+		fgp_flags |= FGP_NOFS;
+	folio = __filemap_get_folio(mapping, index, fgp_flags,
+				    mapping_gfp_mask(mapping));
+	if (!folio)
 		return -ENOMEM;
 
 	if (ops->check_write_begin) {
 		/* Allow the netfs (eg. ceph) to flush conflicts. */
-		ret = ops->check_write_begin(file, pos, len, page, _fsdata);
+		ret = ops->check_write_begin(file, pos, len, folio, _fsdata);
 		if (ret < 0) {
 			trace_netfs_failure(NULL, NULL, ret, netfs_fail_check_write_begin);
 			if (ret == -EAGAIN)
@@ -1111,28 +1112,28 @@ int netfs_write_begin(struct file *file, struct address_space *mapping,
 		}
 	}
 
-	if (PageUptodate(page))
-		goto have_page;
+	if (folio_test_uptodate(folio))
+		goto have_folio;
 
 	/* If the page is beyond the EOF, we want to clear it - unless it's
 	 * within the cache granule containing the EOF, in which case we need
 	 * to preload the granule.
 	 */
 	if (!ops->is_cache_enabled(inode) &&
-	    netfs_skip_page_read(page, pos, len)) {
+	    netfs_skip_folio_read(folio, pos, len)) {
 		netfs_stat(&netfs_n_rh_write_zskip);
-		goto have_page_no_wait;
+		goto have_folio_no_wait;
 	}
 
 	ret = -ENOMEM;
 	rreq = netfs_alloc_read_request(ops, netfs_priv, file);
 	if (!rreq)
 		goto error;
-	rreq->mapping		= page->mapping;
-	rreq->start		= page_offset(page);
-	rreq->len		= thp_size(page);
-	rreq->no_unlock_page	= page->index;
-	__set_bit(NETFS_RREQ_NO_UNLOCK_PAGE, &rreq->flags);
+	rreq->mapping		= folio_file_mapping(folio);
+	rreq->start		= folio_file_pos(folio);
+	rreq->len		= folio_size(folio);
+	rreq->no_unlock_folio	= folio_index(folio);
+	__set_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags);
 	netfs_priv = NULL;
 
 	if (ops->begin_cache_operation) {
@@ -1147,14 +1148,14 @@ int netfs_write_begin(struct file *file, struct address_space *mapping,
 	/* Expand the request to meet caching requirements and download
 	 * preferences.
 	 */
-	ractl._nr_pages = thp_nr_pages(page);
+	ractl._nr_pages = folio_nr_pages(folio);
 	netfs_rreq_expand(rreq, &ractl);
 	netfs_get_read_request(rreq);
 
-	/* We hold the page locks, so we can drop the references */
-	while ((xpage = readahead_page(&ractl)))
-		if (xpage != page)
-			put_page(xpage);
+	/* We hold the folio locks, so we can drop the references */
+	folio_get(folio);
+	while (readahead_folio(&ractl))
+		;
 
 	atomic_set(&rreq->nr_rd_ops, 1);
 	do {
@@ -1184,22 +1185,22 @@ int netfs_write_begin(struct file *file, struct address_space *mapping,
 	if (ret < 0)
 		goto error;
 
-have_page:
-	ret = wait_on_page_fscache_killable(page);
+have_folio:
+	ret = folio_wait_fscache_killable(folio);
 	if (ret < 0)
 		goto error;
-have_page_no_wait:
+have_folio_no_wait:
 	if (netfs_priv)
 		ops->cleanup(netfs_priv, mapping);
-	*_page = page;
+	*_folio = folio;
 	_leave(" = 0");
 	return 0;
 
 error_put:
 	netfs_put_read_request(rreq, false);
 error:
-	unlock_page(page);
-	put_page(page);
+	folio_unlock(folio);
+	folio_put(folio);
 	if (netfs_priv)
 		ops->cleanup(netfs_priv, mapping);
 	_leave(" = %d", ret);
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/trace/events/afs.h b/include/trace/events/afs.h
index bca73e8c8cde..499f5fabd20f 100644
--- a/include/trace/events/afs.h
+++ b/include/trace/events/afs.h
@@ -1016,31 +1016,32 @@ TRACE_EVENT(afs_dir_check_failed,
 		      __entry->vnode, __entry->off, __entry->i_size)
 	    );
 
-TRACE_EVENT(afs_page_dirty,
-	    TP_PROTO(struct afs_vnode *vnode, const char *where, struct page *page),
+TRACE_EVENT(afs_folio_dirty,
+	    TP_PROTO(struct afs_vnode *vnode, const char *where, struct folio *folio),
 
-	    TP_ARGS(vnode, where, page),
+	    TP_ARGS(vnode, where, folio),
 
 	    TP_STRUCT__entry(
 		    __field(struct afs_vnode *,		vnode		)
 		    __field(const char *,		where		)
-		    __field(pgoff_t,			page		)
+		    __field(pgoff_t,			index		)
 		    __field(unsigned long,		from		)
 		    __field(unsigned long,		to		)
 			     ),
 
 	    TP_fast_assign(
+		    unsigned long priv = (unsigned long)folio_get_private(folio);
 		    __entry->vnode = vnode;
 		    __entry->where = where;
-		    __entry->page = page->index;
-		    __entry->from = afs_page_dirty_from(page, page->private);
-		    __entry->to = afs_page_dirty_to(page, page->private);
-		    __entry->to |= (afs_is_page_dirty_mmapped(page->private) ?
-				    (1UL << (BITS_PER_LONG - 1)) : 0);
+		    __entry->index = folio_index(folio);
+		    __entry->from  = afs_folio_dirty_from(folio, priv);
+		    __entry->to    = afs_folio_dirty_to(folio, priv);
+		    __entry->to   |= (afs_is_folio_dirty_mmapped(priv) ?
+				      (1UL << (BITS_PER_LONG - 1)) : 0);
 			   ),
 
 	    TP_printk("vn=%p %lx %s %lx-%lx%s",
-		      __entry->vnode, __entry->page, __entry->where,
+		      __entry->vnode, __entry->index, __entry->where,
 		      __entry->from,
 		      __entry->to & ~(1UL << (BITS_PER_LONG - 1)),
 		      __entry->to & (1UL << (BITS_PER_LONG - 1)) ? " M" : "")

[PATCH v3 6/6] afs: Use folios in directory handling

[David Howells]

Convert the AFS directory handling code to use folios.

With these changes, afs passes -g quick xfstests.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Matthew Wilcox (Oracle) <willy@infradead.org>
cc: Jeff Layton <jlayton@kernel.org>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Ilya Dryomov <idryomov@gmail.com>
cc: linux-afs@lists.infradead.org
cc: ceph-devel@vger.kernel.org
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/162877312172.3085614.992850861791211206.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/162981154845.1901565.2078707403143240098.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/163005746215.2472992.8321380998443828308.stgit@warthog.procyon.org.uk/ # v2
---

 fs/afs/dir.c      |  229 ++++++++++++++++++++++-------------------------------
 fs/afs/dir_edit.c |  154 ++++++++++++++++++------------------
 2 files changed, 174 insertions(+), 209 deletions(-)

diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index 4579bbda4634..da9b4f8577a1 100644
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -103,13 +103,13 @@ struct afs_lookup_cookie {
 };
 
 /*
- * Drop the refs that we're holding on the pages we were reading into.  We've
+ * Drop the refs that we're holding on the folios we were reading into.  We've
  * got refs on the first nr_pages pages.
  */
 static void afs_dir_read_cleanup(struct afs_read *req)
 {
 	struct address_space *mapping = req->vnode->vfs_inode.i_mapping;
-	struct page *page;
+	struct folio *folio;
 	pgoff_t last = req->nr_pages - 1;
 
 	XA_STATE(xas, &mapping->i_pages, 0);
@@ -118,65 +118,56 @@ static void afs_dir_read_cleanup(struct afs_read *req)
 		return;
 
 	rcu_read_lock();
-	xas_for_each(&xas, page, last) {
-		if (xas_retry(&xas, page))
+	xas_for_each(&xas, folio, last) {
+		if (xas_retry(&xas, folio))
 			continue;
-		BUG_ON(xa_is_value(page));
-		BUG_ON(PageCompound(page));
-		ASSERTCMP(page->mapping, ==, mapping);
+		BUG_ON(xa_is_value(folio));
+		ASSERTCMP(folio_file_mapping(folio), ==, mapping);
 
-		put_page(page);
+		folio_put(folio);
 	}
 
 	rcu_read_unlock();
 }
 
 /*
- * check that a directory page is valid
+ * check that a directory folio is valid
  */
-static bool afs_dir_check_page(struct afs_vnode *dvnode, struct page *page,
-			       loff_t i_size)
+static bool afs_dir_check_folio(struct afs_vnode *dvnode, struct folio *folio,
+				loff_t i_size)
 {
-	struct afs_xdr_dir_page *dbuf;
-	loff_t latter, off;
-	int tmp, qty;
+	union afs_xdr_dir_block *block;
+	size_t offset, size;
+	loff_t pos;
 
-	/* Determine how many magic numbers there should be in this page, but
+	/* Determine how many magic numbers there should be in this folio, but
 	 * we must take care because the directory may change size under us.
 	 */
-	off = page_offset(page);
-	if (i_size <= off)
+	pos = folio_pos(folio);
+	if (i_size <= pos)
 		goto checked;
 
-	latter = i_size - off;
-	if (latter >= PAGE_SIZE)
-		qty = PAGE_SIZE;
-	else
-		qty = latter;
-	qty /= sizeof(union afs_xdr_dir_block);
-
-	/* check them */
-	dbuf = kmap_atomic(page);
-	for (tmp = 0; tmp < qty; tmp++) {
-		if (dbuf->blocks[tmp].hdr.magic != AFS_DIR_MAGIC) {
-			printk("kAFS: %s(%lx): bad magic %d/%d is %04hx\n",
-			       __func__, dvnode->vfs_inode.i_ino, tmp, qty,
-			       ntohs(dbuf->blocks[tmp].hdr.magic));
-			trace_afs_dir_check_failed(dvnode, off, i_size);
-			kunmap(page);
+	size = min_t(loff_t, folio_size(folio), i_size - pos);
+	for (offset = 0; offset < size; offset += sizeof(*block)) {
+		block = kmap_local_folio(folio, offset);
+		if (block->hdr.magic != AFS_DIR_MAGIC) {
+			printk("kAFS: %s(%lx): [%llx] bad magic %zx/%zx is %04hx\n",
+			       __func__, dvnode->vfs_inode.i_ino,
+			       pos, offset, size, ntohs(block->hdr.magic));
+			trace_afs_dir_check_failed(dvnode, pos + offset, i_size);
+			kunmap_local(block);
 			trace_afs_file_error(dvnode, -EIO, afs_file_error_dir_bad_magic);
 			goto error;
 		}
 
 		/* Make sure each block is NUL terminated so we can reasonably
-		 * use string functions on it.  The filenames in the page
+		 * use string functions on it.  The filenames in the folio
 		 * *should* be NUL-terminated anyway.
 		 */
-		((u8 *)&dbuf->blocks[tmp])[AFS_DIR_BLOCK_SIZE - 1] = 0;
-	}
-
-	kunmap_atomic(dbuf);
+		((u8 *)block)[AFS_DIR_BLOCK_SIZE - 1] = 0;
 
+		kunmap_local(block);
+	}
 checked:
 	afs_stat_v(dvnode, n_read_dir);
 	return true;
@@ -190,11 +181,11 @@ static bool afs_dir_check_page(struct afs_vnode *dvnode, struct page *page,
  */
 static void afs_dir_dump(struct afs_vnode *dvnode, struct afs_read *req)
 {
-	struct afs_xdr_dir_page *dbuf;
+	union afs_xdr_dir_block *block;
 	struct address_space *mapping = dvnode->vfs_inode.i_mapping;
-	struct page *page;
-	unsigned int i, qty = PAGE_SIZE / sizeof(union afs_xdr_dir_block);
+	struct folio *folio;
 	pgoff_t last = req->nr_pages - 1;
+	size_t offset, size;
 
 	XA_STATE(xas, &mapping->i_pages, 0);
 
@@ -205,30 +196,28 @@ static void afs_dir_dump(struct afs_vnode *dvnode, struct afs_read *req)
 		req->pos, req->nr_pages,
 		req->iter->iov_offset,  iov_iter_count(req->iter));
 
-	xas_for_each(&xas, page, last) {
-		if (xas_retry(&xas, page))
+	xas_for_each(&xas, folio, last) {
+		if (xas_retry(&xas, folio))
 			continue;
 
-		BUG_ON(PageCompound(page));
-		BUG_ON(page->mapping != mapping);
-
-		dbuf = kmap_atomic(page);
-		for (i = 0; i < qty; i++) {
-			union afs_xdr_dir_block *block = &dbuf->blocks[i];
+		BUG_ON(folio_file_mapping(folio) != mapping);
 
-			pr_warn("[%02lx] %32phN\n", page->index * qty + i, block);
+		size = min_t(loff_t, folio_size(folio), req->actual_len - folio_pos(folio));
+		for (offset = 0; offset < size; offset += sizeof(*block)) {
+			block = kmap_local_folio(folio, offset);
+			pr_warn("[%02lx] %32phN\n", folio_index(folio) + offset, block);
+			kunmap_local(block);
 		}
-		kunmap_atomic(dbuf);
 	}
 }
 
 /*
- * Check all the pages in a directory.  All the pages are held pinned.
+ * Check all the blocks in a directory.  All the folios are held pinned.
  */
 static int afs_dir_check(struct afs_vnode *dvnode, struct afs_read *req)
 {
 	struct address_space *mapping = dvnode->vfs_inode.i_mapping;
-	struct page *page;
+	struct folio *folio;
 	pgoff_t last = req->nr_pages - 1;
 	int ret = 0;
 
@@ -238,14 +227,13 @@ static int afs_dir_check(struct afs_vnode *dvnode, struct afs_read *req)
 		return 0;
 
 	rcu_read_lock();
-	xas_for_each(&xas, page, last) {
-		if (xas_retry(&xas, page))
+	xas_for_each(&xas, folio, last) {
+		if (xas_retry(&xas, folio))
 			continue;
 
-		BUG_ON(PageCompound(page));
-		BUG_ON(page->mapping != mapping);
+		BUG_ON(folio_file_mapping(folio) != mapping);
 
-		if (!afs_dir_check_page(dvnode, page, req->file_size)) {
+		if (!afs_dir_check_folio(dvnode, folio, req->actual_len)) {
 			afs_dir_dump(dvnode, req);
 			ret = -EIO;
 			break;
@@ -274,15 +262,16 @@ static int afs_dir_open(struct inode *inode, struct file *file)
 
 /*
  * Read the directory into the pagecache in one go, scrubbing the previous
- * contents.  The list of pages is returned, pinning them so that they don't
+ * contents.  The list of folios is returned, pinning them so that they don't
  * get reclaimed during the iteration.
  */
 static struct afs_read *afs_read_dir(struct afs_vnode *dvnode, struct key *key)
 	__acquires(&dvnode->validate_lock)
 {
+	struct address_space *mapping = dvnode->vfs_inode.i_mapping;
 	struct afs_read *req;
 	loff_t i_size;
-	int nr_pages, i, n;
+	int nr_pages, i;
 	int ret;
 
 	_enter("");
@@ -320,43 +309,30 @@ static struct afs_read *afs_read_dir(struct afs_vnode *dvnode, struct key *key)
 	req->iter = &req->def_iter;
 
 	/* Fill in any gaps that we might find where the memory reclaimer has
-	 * been at work and pin all the pages.  If there are any gaps, we will
+	 * been at work and pin all the folios.  If there are any gaps, we will
 	 * need to reread the entire directory contents.
 	 */
 	i = req->nr_pages;
 	while (i < nr_pages) {
-		struct page *pages[8], *page;
-
-		n = find_get_pages_contig(dvnode->vfs_inode.i_mapping, i,
-					  min_t(unsigned int, nr_pages - i,
-						ARRAY_SIZE(pages)),
-					  pages);
-		_debug("find %u at %u/%u", n, i, nr_pages);
-
-		if (n == 0) {
-			gfp_t gfp = dvnode->vfs_inode.i_mapping->gfp_mask;
+		struct folio *folio;
 
+		folio = filemap_get_folio(mapping, i);
+		if (!folio) {
 			if (test_and_clear_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
 				afs_stat_v(dvnode, n_inval);
 
 			ret = -ENOMEM;
-			page = __page_cache_alloc(gfp);
-			if (!page)
+			folio = __filemap_get_folio(mapping,
+						    i, FGP_LOCK | FGP_CREAT,
+						    mapping->gfp_mask);
+			if (!folio)
 				goto error;
-			ret = add_to_page_cache_lru(page,
-						    dvnode->vfs_inode.i_mapping,
-						    i, gfp);
-			if (ret < 0)
-				goto error;
-
-			attach_page_private(page, (void *)1);
-			unlock_page(page);
-			req->nr_pages++;
-			i++;
-		} else {
-			req->nr_pages += n;
-			i += n;
+			folio_attach_private(folio, (void *)1);
+			folio_unlock(folio);
 		}
+
+		req->nr_pages += folio_nr_pages(folio);
+		i += folio_nr_pages(folio);
 	}
 
 	/* If we're going to reload, we need to lock all the pages to prevent
@@ -424,7 +400,7 @@ static int afs_dir_iterate_block(struct afs_vnode *dvnode,
 	size_t nlen;
 	int tmp;
 
-	_enter("%u,%x,%p,,",(unsigned)ctx->pos,blkoff,block);
+	_enter("%llx,%x", ctx->pos, blkoff);
 
 	curr = (ctx->pos - blkoff) / sizeof(union afs_xdr_dirent);
 
@@ -513,12 +489,10 @@ static int afs_dir_iterate(struct inode *dir, struct dir_context *ctx,
 			   struct key *key, afs_dataversion_t *_dir_version)
 {
 	struct afs_vnode *dvnode = AFS_FS_I(dir);
-	struct afs_xdr_dir_page *dbuf;
 	union afs_xdr_dir_block *dblock;
 	struct afs_read *req;
-	struct page *page;
-	unsigned blkoff, limit;
-	void __rcu **slot;
+	struct folio *folio;
+	unsigned offset, size;
 	int ret;
 
 	_enter("{%lu},%u,,", dir->i_ino, (unsigned)ctx->pos);
@@ -540,43 +514,30 @@ static int afs_dir_iterate(struct inode *dir, struct dir_context *ctx,
 	/* walk through the blocks in sequence */
 	ret = 0;
 	while (ctx->pos < req->actual_len) {
-		blkoff = ctx->pos & ~(sizeof(union afs_xdr_dir_block) - 1);
-
-		/* Fetch the appropriate page from the directory and re-add it
+		/* Fetch the appropriate folio from the directory and re-add it
 		 * to the LRU.  We have all the pages pinned with an extra ref.
 		 */
-		rcu_read_lock();
-		page = NULL;
-		slot = radix_tree_lookup_slot(&dvnode->vfs_inode.i_mapping->i_pages,
-					      blkoff / PAGE_SIZE);
-		if (slot)
-			page = radix_tree_deref_slot(slot);
-		rcu_read_unlock();
-		if (!page) {
+		folio = __filemap_get_folio(dir->i_mapping, ctx->pos / PAGE_SIZE,
+					    FGP_ACCESSED, 0);
+		if (!folio) {
 			ret = afs_bad(dvnode, afs_file_error_dir_missing_page);
 			break;
 		}
-		mark_page_accessed(page);
 
-		limit = blkoff & ~(PAGE_SIZE - 1);
+		offset = round_down(ctx->pos, sizeof(*dblock)) - folio_file_pos(folio);
+		size = min_t(loff_t, folio_size(folio),
+			     req->actual_len - folio_file_pos(folio));
 
-		dbuf = kmap(page);
-
-		/* deal with the individual blocks stashed on this page */
 		do {
-			dblock = &dbuf->blocks[(blkoff % PAGE_SIZE) /
-					       sizeof(union afs_xdr_dir_block)];
-			ret = afs_dir_iterate_block(dvnode, ctx, dblock, blkoff);
-			if (ret != 1) {
-				kunmap(page);
+			dblock = kmap_local_folio(folio, offset);
+			ret = afs_dir_iterate_block(dvnode, ctx, dblock,
+						    folio_file_pos(folio) + offset);
+			kunmap_local(dblock);
+			if (ret != 1)
 				goto out;
-			}
 
-			blkoff += sizeof(union afs_xdr_dir_block);
+		} while (offset += sizeof(*dblock), offset < size);
 
-		} while (ctx->pos < dir->i_size && blkoff < limit);
-
-		kunmap(page);
 		ret = 0;
 	}
 
@@ -2037,42 +1998,42 @@ static int afs_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
 }
 
 /*
- * Release a directory page and clean up its private state if it's not busy
- * - return true if the page can now be released, false if not
+ * Release a directory folio and clean up its private state if it's not busy
+ * - return true if the folio can now be released, false if not
  */
-static int afs_dir_releasepage(struct page *page, gfp_t gfp_flags)
+static int afs_dir_releasepage(struct page *subpage, gfp_t gfp_flags)
 {
-	struct afs_vnode *dvnode = AFS_FS_I(page->mapping->host);
+	struct folio *folio = page_folio(subpage);
+	struct afs_vnode *dvnode = AFS_FS_I(folio_inode(folio));
 
-	_enter("{{%llx:%llu}[%lu]}", dvnode->fid.vid, dvnode->fid.vnode, page->index);
+	_enter("{{%llx:%llu}[%lu]}", dvnode->fid.vid, dvnode->fid.vnode, folio_index(folio));
 
-	detach_page_private(page);
+	folio_detach_private(folio);
 
 	/* The directory will need reloading. */
 	if (test_and_clear_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
 		afs_stat_v(dvnode, n_relpg);
-	return 1;
+	return true;
 }
 
 /*
- * invalidate part or all of a page
- * - release a page and clean up its private data if offset is 0 (indicating
- *   the entire page)
+ * Invalidate part or all of a folio.
  */
-static void afs_dir_invalidatepage(struct page *page, unsigned int offset,
+static void afs_dir_invalidatepage(struct page *subpage, unsigned int offset,
 				   unsigned int length)
 {
-	struct afs_vnode *dvnode = AFS_FS_I(page->mapping->host);
+	struct folio *folio = page_folio(subpage);
+	struct afs_vnode *dvnode = AFS_FS_I(folio_inode(folio));
 
-	_enter("{%lu},%u,%u", page->index, offset, length);
+	_enter("{%lu},%u,%u", folio_index(folio), offset, length);
 
-	BUG_ON(!PageLocked(page));
+	BUG_ON(!folio_test_locked(folio));
 
 	/* The directory will need reloading. */
 	if (test_and_clear_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
 		afs_stat_v(dvnode, n_inval);
 
-	/* we clean up only if the entire page is being invalidated */
-	if (offset == 0 && length == thp_size(page))
-		detach_page_private(page);
+	/* we clean up only if the entire folio is being invalidated */
+	if (offset == 0 && length == folio_size(folio))
+		folio_detach_private(folio);
 }
diff --git a/fs/afs/dir_edit.c b/fs/afs/dir_edit.c
index 540b9fc96824..d98e109ecee9 100644
--- a/fs/afs/dir_edit.c
+++ b/fs/afs/dir_edit.c
@@ -104,6 +104,25 @@ static void afs_clear_contig_bits(union afs_xdr_dir_block *block,
 	block->hdr.bitmap[7] &= ~(u8)(mask >> 7 * 8);
 }
 
+/*
+ * Get a new directory folio.
+ */
+static struct folio *afs_dir_get_folio(struct afs_vnode *vnode, pgoff_t index)
+{
+	struct address_space *mapping = vnode->vfs_inode.i_mapping;
+	struct folio *folio;
+
+	folio = __filemap_get_folio(mapping, index,
+				    FGP_LOCK | FGP_ACCESSED | FGP_CREAT,
+				    mapping->gfp_mask);
+	if (!folio)
+		clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
+	else if (folio && !folio_test_private(folio))
+		folio_attach_private(folio, (void *)1);
+
+	return folio;
+}
+
 /*
  * Scan a directory block looking for a dirent of the right name.
  */
@@ -188,13 +207,11 @@ void afs_edit_dir_add(struct afs_vnode *vnode,
 		      enum afs_edit_dir_reason why)
 {
 	union afs_xdr_dir_block *meta, *block;
-	struct afs_xdr_dir_page *meta_page, *dir_page;
 	union afs_xdr_dirent *de;
-	struct page *page0, *page;
+	struct folio *folio0, *folio;
 	unsigned int need_slots, nr_blocks, b;
 	pgoff_t index;
 	loff_t i_size;
-	gfp_t gfp;
 	int slot;
 
 	_enter(",,{%d,%s},", name->len, name->name);
@@ -206,10 +223,8 @@ void afs_edit_dir_add(struct afs_vnode *vnode,
 		return;
 	}
 
-	gfp = vnode->vfs_inode.i_mapping->gfp_mask;
-	page0 = find_or_create_page(vnode->vfs_inode.i_mapping, 0, gfp);
-	if (!page0) {
-		clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
+	folio0 = afs_dir_get_folio(vnode, 0);
+	if (!folio0) {
 		_leave(" [fgp]");
 		return;
 	}
@@ -217,42 +232,35 @@ void afs_edit_dir_add(struct afs_vnode *vnode,
 	/* Work out how many slots we're going to need. */
 	need_slots = afs_dir_calc_slots(name->len);
 
-	meta_page = kmap(page0);
-	meta = &meta_page->blocks[0];
+	meta = kmap_local_folio(folio0, 0);
 	if (i_size == 0)
 		goto new_directory;
 	nr_blocks = i_size / AFS_DIR_BLOCK_SIZE;
 
-	/* Find a block that has sufficient slots available.  Each VM page
+	/* Find a block that has sufficient slots available.  Each folio
 	 * contains two or more directory blocks.
 	 */
 	for (b = 0; b < nr_blocks + 1; b++) {
-		/* If the directory extended into a new page, then we need to
-		 * tack a new page on the end.
+		/* If the directory extended into a new folio, then we need to
+		 * tack a new folio on the end.
 		 */
 		index = b / AFS_DIR_BLOCKS_PER_PAGE;
-		if (index == 0) {
-			page = page0;
-			dir_page = meta_page;
-		} else {
-			if (nr_blocks >= AFS_DIR_MAX_BLOCKS)
-				goto error;
-			gfp = vnode->vfs_inode.i_mapping->gfp_mask;
-			page = find_or_create_page(vnode->vfs_inode.i_mapping,
-						   index, gfp);
-			if (!page)
+		if (nr_blocks >= AFS_DIR_MAX_BLOCKS)
+			goto error;
+		if (index >= folio_nr_pages(folio0)) {
+			folio = afs_dir_get_folio(vnode, index);
+			if (!folio)
 				goto error;
-			if (!PagePrivate(page))
-				attach_page_private(page, (void *)1);
-			dir_page = kmap(page);
+		} else {
+			folio = folio0;
 		}
 
+		block = kmap_local_folio(folio, b * AFS_DIR_BLOCK_SIZE - folio_file_pos(folio));
+
 		/* Abandon the edit if we got a callback break. */
 		if (!test_bit(AFS_VNODE_DIR_VALID, &vnode->flags))
 			goto invalidated;
 
-		block = &dir_page->blocks[b % AFS_DIR_BLOCKS_PER_PAGE];
-
 		_debug("block %u: %2u %3u %u",
 		       b,
 		       (b < AFS_DIR_BLOCKS_WITH_CTR) ? meta->meta.alloc_ctrs[b] : 99,
@@ -266,7 +274,7 @@ void afs_edit_dir_add(struct afs_vnode *vnode,
 			afs_set_i_size(vnode, (b + 1) * AFS_DIR_BLOCK_SIZE);
 		}
 
-		/* Only lower dir pages have a counter in the header. */
+		/* Only lower dir blocks have a counter in the header. */
 		if (b >= AFS_DIR_BLOCKS_WITH_CTR ||
 		    meta->meta.alloc_ctrs[b] >= need_slots) {
 			/* We need to try and find one or more consecutive
@@ -279,10 +287,10 @@ void afs_edit_dir_add(struct afs_vnode *vnode,
 			}
 		}
 
-		if (page != page0) {
-			unlock_page(page);
-			kunmap(page);
-			put_page(page);
+		kunmap_local(block);
+		if (folio != folio0) {
+			folio_unlock(folio);
+			folio_put(folio);
 		}
 	}
 
@@ -298,8 +306,8 @@ void afs_edit_dir_add(struct afs_vnode *vnode,
 	i_size = AFS_DIR_BLOCK_SIZE;
 	afs_set_i_size(vnode, i_size);
 	slot = AFS_DIR_RESV_BLOCKS0;
-	page = page0;
-	block = meta;
+	folio = folio0;
+	block = kmap_local_folio(folio, 0);
 	nr_blocks = 1;
 	b = 0;
 
@@ -318,10 +326,10 @@ void afs_edit_dir_add(struct afs_vnode *vnode,
 
 	/* Adjust the bitmap. */
 	afs_set_contig_bits(block, slot, need_slots);
-	if (page != page0) {
-		unlock_page(page);
-		kunmap(page);
-		put_page(page);
+	kunmap_local(block);
+	if (folio != folio0) {
+		folio_unlock(folio);
+		folio_put(folio);
 	}
 
 	/* Adjust the allocation counter. */
@@ -333,18 +341,19 @@ void afs_edit_dir_add(struct afs_vnode *vnode,
 	_debug("Insert %s in %u[%u]", name->name, b, slot);
 
 out_unmap:
-	unlock_page(page0);
-	kunmap(page0);
-	put_page(page0);
+	kunmap_local(meta);
+	folio_unlock(folio0);
+	folio_put(folio0);
 	_leave("");
 	return;
 
 invalidated:
 	trace_afs_edit_dir(vnode, why, afs_edit_dir_create_inval, 0, 0, 0, 0, name->name);
 	clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
-	if (page != page0) {
-		kunmap(page);
-		put_page(page);
+	kunmap_local(block);
+	if (folio != folio0) {
+		folio_unlock(folio);
+		folio_put(folio);
 	}
 	goto out_unmap;
 
@@ -364,10 +373,9 @@ void afs_edit_dir_add(struct afs_vnode *vnode,
 void afs_edit_dir_remove(struct afs_vnode *vnode,
 			 struct qstr *name, enum afs_edit_dir_reason why)
 {
-	struct afs_xdr_dir_page *meta_page, *dir_page;
 	union afs_xdr_dir_block *meta, *block;
 	union afs_xdr_dirent *de;
-	struct page *page0, *page;
+	struct folio *folio0, *folio;
 	unsigned int need_slots, nr_blocks, b;
 	pgoff_t index;
 	loff_t i_size;
@@ -384,9 +392,8 @@ void afs_edit_dir_remove(struct afs_vnode *vnode,
 	}
 	nr_blocks = i_size / AFS_DIR_BLOCK_SIZE;
 
-	page0 = find_lock_page(vnode->vfs_inode.i_mapping, 0);
-	if (!page0) {
-		clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
+	folio0 = afs_dir_get_folio(vnode, 0);
+	if (!folio0) {
 		_leave(" [fgp]");
 		return;
 	}
@@ -394,30 +401,27 @@ void afs_edit_dir_remove(struct afs_vnode *vnode,
 	/* Work out how many slots we're going to discard. */
 	need_slots = afs_dir_calc_slots(name->len);
 
-	meta_page = kmap(page0);
-	meta = &meta_page->blocks[0];
+	meta = kmap_local_folio(folio0, 0);
 
-	/* Find a page that has sufficient slots available.  Each VM page
+	/* Find a block that has sufficient slots available.  Each folio
 	 * contains two or more directory blocks.
 	 */
 	for (b = 0; b < nr_blocks; b++) {
 		index = b / AFS_DIR_BLOCKS_PER_PAGE;
-		if (index != 0) {
-			page = find_lock_page(vnode->vfs_inode.i_mapping, index);
-			if (!page)
+		if (index >= folio_nr_pages(folio0)) {
+			folio = afs_dir_get_folio(vnode, index);
+			if (!folio)
 				goto error;
-			dir_page = kmap(page);
 		} else {
-			page = page0;
-			dir_page = meta_page;
+			folio = folio0;
 		}
 
+		block = kmap_local_folio(folio, b * AFS_DIR_BLOCK_SIZE - folio_file_pos(folio));
+
 		/* Abandon the edit if we got a callback break. */
 		if (!test_bit(AFS_VNODE_DIR_VALID, &vnode->flags))
 			goto invalidated;
 
-		block = &dir_page->blocks[b % AFS_DIR_BLOCKS_PER_PAGE];
-
 		if (b > AFS_DIR_BLOCKS_WITH_CTR ||
 		    meta->meta.alloc_ctrs[b] <= AFS_DIR_SLOTS_PER_BLOCK - 1 - need_slots) {
 			slot = afs_dir_scan_block(block, name, b);
@@ -425,10 +429,10 @@ void afs_edit_dir_remove(struct afs_vnode *vnode,
 				goto found_dirent;
 		}
 
-		if (page != page0) {
-			unlock_page(page);
-			kunmap(page);
-			put_page(page);
+		kunmap_local(block);
+		if (folio != folio0) {
+			folio_unlock(folio);
+			folio_put(folio);
 		}
 	}
 
@@ -449,10 +453,10 @@ void afs_edit_dir_remove(struct afs_vnode *vnode,
 
 	/* Adjust the bitmap. */
 	afs_clear_contig_bits(block, slot, need_slots);
-	if (page != page0) {
-		unlock_page(page);
-		kunmap(page);
-		put_page(page);
+	kunmap_local(block);
+	if (folio != folio0) {
+		folio_unlock(folio);
+		folio_put(folio);
 	}
 
 	/* Adjust the allocation counter. */
@@ -464,9 +468,9 @@ void afs_edit_dir_remove(struct afs_vnode *vnode,
 	_debug("Remove %s from %u[%u]", name->name, b, slot);
 
 out_unmap:
-	unlock_page(page0);
-	kunmap(page0);
-	put_page(page0);
+	kunmap_local(meta);
+	folio_unlock(folio0);
+	folio_put(folio0);
 	_leave("");
 	return;
 
@@ -474,10 +478,10 @@ void afs_edit_dir_remove(struct afs_vnode *vnode,
 	trace_afs_edit_dir(vnode, why, afs_edit_dir_delete_inval,
 			   0, 0, 0, 0, name->name);
 	clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
-	if (page != page0) {
-		unlock_page(page);
-		kunmap(page);
-		put_page(page);
+	kunmap_local(block);
+	if (folio != folio0) {
+		folio_unlock(folio);
+		folio_put(folio);
 	}
 	goto out_unmap;
 

Re: [PATCH v3 4/6] folio: Add a function to get the host inode for a folio

[Matthew Wilcox]

On Tue, Nov 02, 2021 at 08:30:46AM +0000, David Howells wrote:
> Add a convenience function, folio_inode() that will get the host inode from
> a folio's mapping.

I'm not opposed, but it only saves two characters, so I'm not entirely
sure it justifies its existance.  On the other hand, folio_inode() is
clear about what it does.

> + * For folios which are in the page cache, return the inode that is hosting
> + * this folio belongs to.

This looks like an editing mistake.  Either you meant
'return the inode that hosts this folio' or
'return the inode this folio belongs to'
(and i prefer the second).

With that grammo fixed,

Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>

Re: [PATCH v3 5/6] netfs, 9p, afs, ceph: Use folios

[Matthew Wilcox]

On Tue, Nov 02, 2021 at 08:31:14AM +0000, David Howells wrote:
> -static int v9fs_vfs_writepage_locked(struct page *page)
> +static int v9fs_vfs_write_folio_locked(struct folio *folio)
>  {
> -	struct inode *inode = page->mapping->host;
> +	struct inode *inode = folio_inode(folio);
>  	struct v9fs_inode *v9inode = V9FS_I(inode);
> -	loff_t start = page_offset(page);
> +	loff_t start = folio_pos(folio);
>  	loff_t size = i_size_read(inode);
>  	struct iov_iter from;
> -	int err, len;
> +	size_t gran = folio_size(folio), len;
> +	int err;
>  
> -	if (page->index == size >> PAGE_SHIFT)
> -		len = size & ~PAGE_MASK;
> -	else
> -		len = PAGE_SIZE;
> +	len = (size >= start + gran) ? gran : size - start;

This seems like the most complicated way to write this ... how about:

        size_t len = min_t(loff_t, isize - start, folio_size(folio));

> @@ -322,23 +322,24 @@ static void afs_req_issue_op(struct netfs_read_subrequest *subreq)
>  
>  static int afs_symlink_readpage(struct file *file, struct page *page)
>  {
> -	struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
> +	struct afs_vnode *vnode = AFS_FS_I(page_mapping(page)->host);

How does swap end up calling readpage on a symlink?

>  	ret = afs_fetch_data(fsreq->vnode, fsreq);
> -	page_endio(page, false, ret);
> +	page_endio(&folio->page, false, ret);

We need a folio_endio() ...

>  int afs_write_end(struct file *file, struct address_space *mapping,
>  		  loff_t pos, unsigned len, unsigned copied,
> -		  struct page *page, void *fsdata)
> +		  struct page *subpage, void *fsdata)
>  {
> +	struct folio *folio = page_folio(subpage);
>  	struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
>  	unsigned long priv;
> -	unsigned int f, from = pos & (thp_size(page) - 1);
> +	unsigned int f, from = pos & (folio_size(folio) - 1);

Isn't that:

	size_t from = offset_in_folio(folio, pos);

(not that i think we're getting folios larger than 4GB any time soon,
but it'd be nice to be prepared for it)

Re: [PATCH v3 4/6] folio: Add a function to get the host inode for a folio

[David Howells]

Matthew Wilcox <willy@infradead.org> wrote:

> > + * For folios which are in the page cache, return the inode that is hosting
> > + * this folio belongs to.
> 
> This looks like an editing mistake.  Either you meant
> 'return the inode that hosts this folio' or
> 'return the inode this folio belongs to'
> (and i prefer the second).

Yeah - I'll go with that.

David

Re: [PATCH v3 5/6] netfs, 9p, afs, ceph: Use folios

[David Howells]

Matthew Wilcox <willy@infradead.org> wrote:

> > +	len = (size >= start + gran) ? gran : size - start;
> 
> This seems like the most complicated way to write this ... how about:
> 
>         size_t len = min_t(loff_t, isize - start, folio_size(folio));

I was trying to hedge against isize-start going negative.  Can this code race
against truncate?  truncate_setsize() changes i_size *before* invalidating the
pages.

> >  static int afs_symlink_readpage(struct file *file, struct page *page)
> >  {
> > -	struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
> > +	struct afs_vnode *vnode = AFS_FS_I(page_mapping(page)->host);
> 
> How does swap end up calling readpage on a symlink?

Um - readpage is called to read the symlink.

> > -	page_endio(page, false, ret);
> > +	page_endio(&folio->page, false, ret);
> 
> We need a folio_endio() ...

I think we mentioned this before and I think you said you had or would make a
patch for it.  I can just create a wrapper for it if that'll do.

David

[PATCH] folio: Add replacements for page_endio()

[David Howells]

Add three functions to replace page_endio():

 (1) folio_end_read().  End a read to a folio.

 (2) folio_end_write().  End a write from a folio.

 (3) folio_endio().  A switcher that does one or the other of the above.

Change page_endio() to just call folio_endio().  Note that the parameter
order is switched so that the folio_endio() stub doesn't have to shuffle
the params around, but can rather just test and jump.

Signed-off-by: David Howells <dhowells@redhat.com>
---
 include/linux/pagemap.h |    9 ++++++
 mm/filemap.c            |   64 ++++++++++++++++++++++++++++++++----------------
 2 files changed, 51 insertions(+), 22 deletions(-)


diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index e4b98714f763..29b4ee189cb8 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -845,7 +845,14 @@ static inline int __must_check write_one_page(struct page *page)
 int __set_page_dirty_nobuffers(struct page *page);
 int __set_page_dirty_no_writeback(struct page *page);
 
-void page_endio(struct page *page, bool is_write, int err);
+void folio_end_read(struct folio *folio, int err);
+void folio_end_write(struct folio *folio, int err);
+void folio_endio(struct folio *folio, int err, bool is_write);
+
+static inline void page_endio(struct page *page, bool is_write, int err)
+{
+	folio_endio(page_folio(page), err, is_write);
+}
 
 void folio_end_private_2(struct folio *folio);
 void folio_wait_private_2(struct folio *folio);
diff --git a/mm/filemap.c b/mm/filemap.c
index bfcef6ff7a27..e4e90f96bf1c 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1596,33 +1596,55 @@ void folio_end_writeback(struct folio *folio)
 }
 EXPORT_SYMBOL(folio_end_writeback);
 
-/*
- * After completing I/O on a page, call this routine to update the page
- * flags appropriately
+/**
+ * folio_end_read - Update the state of a folio after a read
+ * @folio: The folio to update
+ * @err: The error code (or 0) to apply
  */
-void page_endio(struct page *page, bool is_write, int err)
+void folio_end_read(struct folio *folio, int err)
 {
-	if (!is_write) {
-		if (!err) {
-			SetPageUptodate(page);
-		} else {
-			ClearPageUptodate(page);
-			SetPageError(page);
-		}
-		unlock_page(page);
+	if (!err) {
+		folio_mark_uptodate(folio);
 	} else {
-		if (err) {
-			struct address_space *mapping;
+		folio_clear_uptodate(folio);
+		folio_set_error(folio);
+	}
+	folio_unlock(folio);
+}
+EXPORT_SYMBOL_GPL(folio_end_read);
 
-			SetPageError(page);
-			mapping = page_mapping(page);
-			if (mapping)
-				mapping_set_error(mapping, err);
-		}
-		end_page_writeback(page);
+/**
+ * folio_end_write - Update the state of a folio after a write
+ * @folio: The folio to update
+ * @err: The error code (or 0) to apply
+ */
+void folio_end_write(struct folio *folio, int err)
+{
+	if (err) {
+		struct address_space *mapping = folio_mapping(folio);
+
+		folio_set_error(folio);
+		if (mapping)
+			mapping_set_error(mapping, err);
 	}
+	folio_end_writeback(folio);
+}
+EXPORT_SYMBOL_GPL(folio_end_write);
+
+/**
+ * folio_endio - Update the state of a folio after a read or write
+ * @folio: The folio to update
+ * @err: The error code (or 0) to apply
+ * @is_write: True if this was a write
+ */
+void folio_endio(struct folio *folio, int err, bool is_write)
+{
+	if (is_write)
+		folio_end_write(folio, err);
+	else
+		folio_end_read(folio, err);
 }
-EXPORT_SYMBOL_GPL(page_endio);
+EXPORT_SYMBOL_GPL(folio_endio);
 
 /**
  * __folio_lock - Get a lock on the folio, assuming we need to sleep to get it.

Re: [PATCH v3 5/6] netfs, 9p, afs, ceph: Use folios

[Matthew Wilcox]

On Wed, Nov 03, 2021 at 02:58:12PM +0000, David Howells wrote:
> Matthew Wilcox <willy@infradead.org> wrote:
> 
> > > +	len = (size >= start + gran) ? gran : size - start;
> > 
> > This seems like the most complicated way to write this ... how about:
> > 
> >         size_t len = min_t(loff_t, isize - start, folio_size(folio));
> 
> I was trying to hedge against isize-start going negative.  Can this code race
> against truncate?  truncate_setsize() changes i_size *before* invalidating the
> pages.

We should check for isize < start separately, and skip the writeback
entirely.

> > >  static int afs_symlink_readpage(struct file *file, struct page *page)
> > >  {
> > > -	struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
> > > +	struct afs_vnode *vnode = AFS_FS_I(page_mapping(page)->host);
> > 
> > How does swap end up calling readpage on a symlink?
> 
> Um - readpage is called to read the symlink.

But the only reason to use page_mapping() instead of page->mapping
is if you don't know that the page is in the page cache.  You know
that here, so I don't understand why you changed it.

> > > -	page_endio(page, false, ret);
> > > +	page_endio(&folio->page, false, ret);
> > 
> > We need a folio_endio() ...
> 
> I think we mentioned this before and I think you said you had or would make a
> patch for it.  I can just create a wrapper for it if that'll do.

Probably better to convert it and put a page_endio wrapper in
folio-compat.c

Re: [PATCH v3 5/6] netfs, 9p, afs, ceph: Use folios

[David Howells]

Matthew Wilcox <willy@infradead.org> wrote:

> On Wed, Nov 03, 2021 at 02:58:12PM +0000, David Howells wrote:
> > Matthew Wilcox <willy@infradead.org> wrote:
> > 
> > > > +	len = (size >= start + gran) ? gran : size - start;
> > > 
> > > This seems like the most complicated way to write this ... how about:
> > > 
> > >         size_t len = min_t(loff_t, isize - start, folio_size(folio));
> > 
> > I was trying to hedge against isize-start going negative.  Can this code race
> > against truncate?  truncate_setsize() changes i_size *before* invalidating the
> > pages.
> 
> We should check for isize < start separately, and skip the writeback
> entirely.

So, something like the following

	static int v9fs_vfs_write_folio_locked(struct folio *folio)
	{
		struct inode *inode = folio_inode(folio);
		struct v9fs_inode *v9inode = V9FS_I(inode);
		loff_t start = folio_pos(folio);
		loff_t i_size = i_size_read(inode);
		struct iov_iter from;
		size_t len = folio_size(folio);
		int err;

		if (start >= i_size)
			return 0; /* Simultaneous truncation occurred */

		len = min_t(loff_t, i_size - start, len);

		iov_iter_xarray(&from, ..., start, len);
		...
	}

David