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, 43 insertions, 37 deletions

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 @@ out:
  */
 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);