mm,jfs: move write_one_page/folio_write_one to jfs

The last remaining user of folio_write_one through the write_one_page
wrapper is jfs, so move the functionality there and hard code the
call to metapage_writepage.

Note that the use of the pagecache by the JFS 'metapage' buffer cache
is a bit odd, and we could probably do without VM-level dirty tracking
at all, but that's a change for another time.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/jfs/jfs_metapage.c

@@ -691,6 +691,35 @@ void grab_metapage(struct metapage * mp)
 	unlock_page(mp->page);
 }
 
+static int metapage_write_one(struct page *page)
+{
+	struct folio *folio = page_folio(page);
+	struct address_space *mapping = folio->mapping;
+	struct writeback_control wbc = {
+		.sync_mode = WB_SYNC_ALL,
+		.nr_to_write = folio_nr_pages(folio),
+	};
+	int ret = 0;
+
+	BUG_ON(!folio_test_locked(folio));
+
+	folio_wait_writeback(folio);
+
+	if (folio_clear_dirty_for_io(folio)) {
+		folio_get(folio);
+		ret = metapage_writepage(page, &wbc);
+		if (ret == 0)
+			folio_wait_writeback(folio);
+		folio_put(folio);
+	} else {
+		folio_unlock(folio);
+	}
+
+	if (!ret)
+		ret = filemap_check_errors(mapping);
+	return ret;
+}
+
 void force_metapage(struct metapage *mp)
 {
 	struct page *page = mp->page;
@@ -700,8 +729,8 @@ void force_metapage(struct metapage *mp)
 	get_page(page);
 	lock_page(page);
 	set_page_dirty(page);
-	if (write_one_page(page))
-		jfs_error(mp->sb, "write_one_page() failed\n");
+	if (metapage_write_one(page))
+		jfs_error(mp->sb, "metapage_write_one() failed\n");
 	clear_bit(META_forcewrite, &mp->flag);
 	put_page(page);
 }
@@ -746,9 +775,9 @@ void release_metapage(struct metapage * mp)
 		set_page_dirty(page);
 		if (test_bit(META_sync, &mp->flag)) {
 			clear_bit(META_sync, &mp->flag);
-			if (write_one_page(page))
-				jfs_error(mp->sb, "write_one_page() failed\n");
-			lock_page(page); /* write_one_page unlocks the page */
+			if (metapage_write_one(page))
+				jfs_error(mp->sb, "metapage_write_one() failed\n");
+			lock_page(page);
 		}
 	} else if (mp->lsn)	/* discard_metapage doesn't remove it */
 		remove_from_logsync(mp);

include/linux/pagemap.h

@@ -1066,12 +1066,6 @@ static inline void folio_cancel_dirty(struct folio *folio)
 bool folio_clear_dirty_for_io(struct folio *folio);
 bool clear_page_dirty_for_io(struct page *page);
 void folio_invalidate(struct folio *folio, size_t offset, size_t length);
-int __must_check folio_write_one(struct folio *folio);
-static inline int __must_check write_one_page(struct page *page)
-{
-	return folio_write_one(page_folio(page));
-}
-
 int __set_page_dirty_nobuffers(struct page *page);
 bool noop_dirty_folio(struct address_space *mapping, struct folio *folio);
 

mm/page-writeback.c

@@ -2583,46 +2583,6 @@ int do_writepages(struct address_space *mapping, struct writeback_control *wbc)
 	return ret;
 }
 
-/**
- * folio_write_one - write out a single folio and wait on I/O.
- * @folio: The folio to write.
- *
- * The folio must be locked by the caller and will be unlocked upon return.
- *
- * Note that the mapping's AS_EIO/AS_ENOSPC flags will be cleared when this
- * function returns.
- *
- * Return: %0 on success, negative error code otherwise
- */
-int folio_write_one(struct folio *folio)
-{
-	struct address_space *mapping = folio->mapping;
-	int ret = 0;
-	struct writeback_control wbc = {
-		.sync_mode = WB_SYNC_ALL,
-		.nr_to_write = folio_nr_pages(folio),
-	};
-
-	BUG_ON(!folio_test_locked(folio));
-
-	folio_wait_writeback(folio);
-
-	if (folio_clear_dirty_for_io(folio)) {
-		folio_get(folio);
-		ret = mapping->a_ops->writepage(&folio->page, &wbc);
-		if (ret == 0)
-			folio_wait_writeback(folio);
-		folio_put(folio);
-	} else {
-		folio_unlock(folio);
-	}
-
-	if (!ret)
-		ret = filemap_check_errors(mapping);
-	return ret;
-}
-EXPORT_SYMBOL(folio_write_one);
-
 /*
  * For address_spaces which do not use buffers nor write back.
  */