jfs: Change metapage->page to metapage->folio

Convert all the users to operate on a folio. Saves sixteen calls to
compound_head(). We still use sizeof(struct page) in print_hex_dump,
otherwise it will go into the second and third pages of the folio which
won't exist for jfs folios (since they are not large). This needs a
better solution, but finding it can be postponed.

Signed-off-by: Matthew Wilcox (Oracle) <[e-mail]>
Signed-off-by: Dave Kleikamp <[e-mail]>

fs/jfs/jfs_logmgr.c

···
 					       mp, sizeof(struct metapage), 0);
 				print_hex_dump(KERN_ERR, "page: ",
 					       DUMP_PREFIX_ADDRESS, 16,
-					       sizeof(long), mp->page,
+					       sizeof(long), mp->folio,
 					       sizeof(struct page), 0);
 			} else
 				print_hex_dump(KERN_ERR, "tblock:",

fs/jfs/jfs_metapage.c

···
 	do {
 		set_current_state(TASK_UNINTERRUPTIBLE);
 		if (metapage_locked(mp)) {
-			unlock_page(mp->page);
+			folio_unlock(mp->folio);
 			io_schedule();
-			lock_page(mp->page);
+			folio_lock(mp->folio);
 		}
 	} while (trylock_metapage(mp));
 	__set_current_state(TASK_RUNNING);
···
 }
 
 /*
- * Must have mp->page locked
+ * Must have mp->folio locked
  */
 static inline void lock_metapage(struct metapage *mp)
 {
···
 		mp = alloc_metapage(GFP_NOFS);
 		if (!mp)
 			goto unlock;
-		mp->page = &folio->page;
+		mp->folio = folio;
 		mp->sb = inode->i_sb;
 		mp->flag = 0;
 		mp->xflag = COMMIT_PAGE;
···
 void grab_metapage(struct metapage * mp)
 {
 	jfs_info("grab_metapage: mp = 0x%p", mp);
-	get_page(mp->page);
-	lock_page(mp->page);
+	folio_get(mp->folio);
+	folio_lock(mp->folio);
 	mp->count++;
 	lock_metapage(mp);
-	unlock_page(mp->page);
+	folio_unlock(mp->folio);
 }
 
 static int metapage_write_one(struct folio *folio)
···
 
 void force_metapage(struct metapage *mp)
 {
-	struct folio *folio = page_folio(mp->page);
+	struct folio *folio = mp->folio;
 	jfs_info("force_metapage: mp = 0x%p", mp);
 	set_bit(META_forcewrite, &mp->flag);
 	clear_bit(META_sync, &mp->flag);
···
 
 void hold_metapage(struct metapage *mp)
 {
-	lock_page(mp->page);
+	folio_lock(mp->folio);
 }
 
 void put_metapage(struct metapage *mp)
 {
 	if (mp->count || mp->nohomeok) {
 		/* Someone else will release this */
-		unlock_page(mp->page);
+		folio_unlock(mp->folio);
 		return;
 	}
-	get_page(mp->page);
+	folio_get(mp->folio);
 	mp->count++;
 	lock_metapage(mp);
-	unlock_page(mp->page);
+	folio_unlock(mp->folio);
 	release_metapage(mp);
 }
 
 void release_metapage(struct metapage * mp)
 {
-	struct folio *folio = page_folio(mp->page);
+	struct folio *folio = mp->folio;
 	jfs_info("release_metapage: mp = 0x%p, flag = 0x%lx", mp, mp->flag);
 
 	folio_lock(folio);

fs/jfs/jfs_metapage.h

···
 	wait_queue_head_t wait;
 
 	/* implementation */
-	struct page *page;
+	struct folio *folio;
 	struct super_block *sb;
 	unsigned int logical_size;
 
···
 
 static inline void metapage_nohomeok(struct metapage *mp)
 {
-	struct page *page = mp->page;
-	lock_page(page);
+	struct folio *folio = mp->folio;
+	folio_lock(folio);
 	if (!mp->nohomeok++) {
 		mark_metapage_dirty(mp);
-		get_page(page);
-		wait_on_page_writeback(page);
+		folio_get(folio);
+		folio_wait_writeback(folio);
 	}
-	unlock_page(page);
+	folio_unlock(folio);
 }
 
 /*
···
 static inline void metapage_wait_for_io(struct metapage *mp)
 {
 	if (test_bit(META_io, &mp->flag))
-		wait_on_page_writeback(mp->page);
+		folio_wait_writeback(mp->folio);
 }
 
 /*
···
 static inline void _metapage_homeok(struct metapage *mp)
 {
 	if (!--mp->nohomeok)
-		put_page(mp->page);
+		folio_put(mp->folio);
 }
 
 static inline void metapage_homeok(struct metapage *mp)