Re: [PATCH v2 5/6] netfs, afs, ceph: Use folios

[Jeff Layton]

On Fri, 2021-08-27 at 10:44 +0100, David Howells wrote:
> Convert the netfs helper library to use folios throughout, convert the afs
> filesystem to use folios in its file I/O paths and convert the ceph
> filesystem to use just enough folios to compile.
> 
> With these changes, afs passes -g quick xfstests.
> 
> Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
> cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
> cc: Jeff Layton <jlayton@xxxxxxxxxx>
> cc: Marc Dionne <marc.dionne@xxxxxxxxxxxx>
> cc: Ilya Dryomov <idryomov@xxxxxxxxx>
> cc: linux-afs@xxxxxxxxxxxxxxxxxxx
> cc: ceph-devel@xxxxxxxxxxxxxxx
> cc: linux-cachefs@xxxxxxxxxx
> Link: https://lore.kernel.org/r/2408234.1628687271@xxxxxxxxxxxxxxxxxxxxxx/ # rfc
> Link: https://lore.kernel.org/r/162877311459.3085614.10601478228012245108.stgit@xxxxxxxxxxxxxxxxxxxxxx/
> Link: https://lore.kernel.org/r/162981153551.1901565.3124454657133703341.stgit@xxxxxxxxxxxxxxxxxxxxxx/
> ---
> 
>  fs/afs/file.c              |   70 +++++----
>  fs/afs/internal.h          |   46 +++---
>  fs/afs/write.c             |  332 +++++++++++++++++++++-----------------------
>  fs/ceph/addr.c             |   80 ++++++-----
>  fs/netfs/read_helper.c     |  165 +++++++++++-----------
>  include/linux/netfs.h      |   12 +-
>  include/trace/events/afs.h |   21 +--
>  7 files changed, 363 insertions(+), 363 deletions(-)
> 
> diff --git a/fs/afs/file.c b/fs/afs/file.c
> index daa9106b9654..2c07958cde95 100644
> --- a/fs/afs/file.c
> +++ b/fs/afs/file.c
> @@ -315,23 +315,24 @@ 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_file_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;
>  }
>  
> @@ -355,7 +356,7 @@ 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));
>  
> @@ -378,7 +379,9 @@ 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)
> @@ -390,29 +393,29 @@ 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 */
> @@ -430,17 +433,17 @@ 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);
>  }
>  
>  /*
> @@ -451,14 +454,16 @@ 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("");
>  }
>  
> @@ -468,30 +473,31 @@ 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;
>  }
>  
>  /*
> diff --git a/fs/afs/internal.h b/fs/afs/internal.h
> index beaef0387e85..f16cc7d7ae1d 100644
> --- a/fs/afs/internal.h
> +++ b/fs/afs/internal.h
> @@ -867,59 +867,59 @@ 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 5c977deeeee0..4e19672e634d 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;
>  }
> @@ -109,14 +109,15 @@ int afs_write_end(struct file *file, struct address_space *mapping,
>  		  loff_t pos, unsigned len, unsigned copied,
>  		  struct page *page, void *fsdata)
>  {
> +	struct folio *folio = page_folio(page);
>  	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 (copied < len) {
> @@ -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;
> @@ -456,37 +439,37 @@ 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)))
> +			if (unlikely(folio != xas_reload(&xas)))
>  				break;
>  
> -			if (!trylock_page(page))
> +			if (!folio_trylock(folio))
>  				break;
> -			if (!PageDirty(page) || PageWriteback(page)) {
> -				unlock_page(page);
> +			if (!folio_test_dirty(folio) || folio_test_writeback(folio)) {
> +				folio_unlock(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);
> +				folio_unlock(folio);
>  				break;
>  			}
>  
> @@ -497,8 +480,8 @@ 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;
> @@ -515,16 +498,16 @@ 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);
> @@ -538,10 +521,10 @@ 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;
> @@ -552,22 +535,22 @@ 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;
> @@ -580,7 +563,7 @@ 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);
> @@ -590,7 +573,7 @@ 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);
> @@ -651,16 +634,17 @@ 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_file_mapping(folio), wbc,
> +					       folio, start, LLONG_MAX - start);
>  	if (ret < 0) {
>  		_leave(" = %zd", ret);
>  		return ret;
> @@ -677,7 +661,8 @@ 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;
>  
> @@ -687,13 +672,14 @@ 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_file_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
> @@ -701,37 +687,38 @@ 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_file_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;
> @@ -840,14 +827,13 @@ 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);
>  	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));
>  
>  	sb_start_pagefault(inode->i_sb);
>  
> @@ -855,18 +841,18 @@ 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.
>  	 */
> @@ -875,14 +861,14 @@ 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);
>  
> @@ -923,38 +909,38 @@ 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 a1e2813731d1..49aa41555baf 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);
>  
>  	/* zero the stale part of the page if we did a short copy */
> -	if (!PageUptodate(page)) {
> +	if (!folio_test_uptodate(folio)) {
>  		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 0b6cd3b8734c..2ad91f9e2a45 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 113b5fa9280c..cb2aee4258ac 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 3ccf591b2374..d3d8abf3f8df 100644
> --- a/include/trace/events/afs.h
> +++ b/include/trace/events/afs.h
> @@ -955,31 +955,32 @@ 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" : "")
> 
> 


The conversion looks fairly straightforward substituting folios for
pages in this code. You can add this for the ceph and netfs parts (I'm
less well-versed in the AFS bits):

Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>

FWIW, I've also done some testing with a pile that contained this series
and it seems to behave as expected.