netfs, 9p, afs, ceph: Use folios

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 #5:
 - Got rid of folio_end{io,_read,_write}() and inlined the stuff it does
   instead (Willy decided he didn't want this after all).

ver #4:
 - Fixed a bug in afs_redirty_page() whereby it didn't set the next page
   index in the loop and returned too early.
 - Simplified a check in v9fs_vfs_write_folio_locked()[1].
 - Undid a change to afs_symlink_readpage()[1].
 - Used offset_in_folio() in afs_write_end()[1].
 - Changed from using page_endio() to folio_end{io,_read,_write}()[1].

ver #2:
 - Add 9p foliation.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Tested-by: Jeff Layton <jlayton@kernel.org>
Tested-by: Dominique Martinet <asmadeus@codewreck.org>
Tested-by: kafs-testing@auristor.com
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/YYKa3bfQZxK5/wDN@casper.infradead.org/ [1]
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
Link: https://lore.kernel.org/r/163584187452.4023316.500389675405550116.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/163649328026.309189.1124218109373941936.stgit@warthog.procyon.org.uk/ # v4
Link: https://lore.kernel.org/r/163657852454.834781.9265101983152100556.stgit@warthog.procyon.org.uk/ # v5

1 files changed, 39 insertions, 31 deletions

diff --git a/fs/afs/file.c b/fs/afs/file.c
index eb11d047c0ae..cb6ad61eec3b 100644
--- a/fs/afs/file.c
+++ b/fs/afs/file.c
@@ -324,21 +324,24 @@ 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;
+	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);
+	if (ret == 0)
+		SetPageUptodate(page);
+	unlock_page(page);
 	return ret;
 }
 
@@ -362,7 +365,7 @@ 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 +388,9 @@ 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 +402,29 @@ 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 +442,17 @@ 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 +463,16 @@ full_invalidate:
 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 +482,31 @@ 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)